Article made from nitrile rubber, having natural rubber characteristics
SUBSTANCE: invention relates to a method and material for making elastomeric articles from nitrile rubber. The elastomeric article is made from carboxylated butadiene-nitrile rubber composition in latex form. The rubber composition consists of two acrylo-nitrile compositions - first and second, taken in ratio between 60:40 and 40:60. The rubber composition has glass transition temperature Tg between -15°C and -30°C. The composition contains a proportional amount of alkali metal and metal oxide, where the amount of metal hydroxide is equal to 0-1.5 parts, and the amount of the metal oxide is greater than 0.5 but less than or equal to 1.5 parts per 100 dry parts of rubber. The article has given thickness of up to 0.12 mm.
EFFECT: invention enables to obtain a nitrile rubber-based article such as elastomeric gloves, having properties which characterise force and deformation correlation, comparable with characteristics of articles made from natural rubber latex, and retaining tensile strength on the same level as nitrile rubber.
12 cl, 4 dwg, 4 tbl
This application claims priority based on application U.S. No. 60/680971, filed may 13, 2005, the contents of which are incorporated into the present application by reference.
The technical field
The present invention relates to elastomeric products, izgotovliaemye of nitrile rubber compositions. More specifically, the invention relates to articles of carboxylating butadiene-Acrylonitrile rubber, which have physical characteristics comparable with the characteristics of similar products from natural latex rubber.
The level of technology
The development of modern rubber materials has made possible the manufacture of a wide range of elastomeric products having variable properties in terms of strength and chemical resistance. The creation of synthetic latex materials have made it possible to accommodate various elastic and polymeric materials for use in the manufacture of various industrial products. One useful class of compositions based on synthetic rubber material comprises a nitrile rubber, which is widely used for the manufacture of articles such as gloves and oil resistant seals.
Elastomeric products requiring for their production of materials having a maximum elongation and exceptionally easy to grow the structure, such as surgical or examination (diagnostic) gloves, balloons and condoms, traditionally made from natural rubber latex. Although nitrile rubber products, as a rule, more difficult to stretch, one of the advantages of nitrile rubber before the substrates are made of natural rubber latex is that products made of nitrile rubber does not contain natural latex proteins that can cause severe allergies in some users. Other advantages of nitrile materials before natural rubber latex include more high chemical resistance, especially to fatty and oily substances, and higher resistance to puncturing. Therefore, gloves based on nitrile rubber steel is widely and readily be used as a substitute for products from natural rubber.
While hospitals, laboratories or other institutions, which can be used rubber gloves, often require, to better protect their staff to eliminate the use of latex, higher, as a rule, the cost of nitrile products often limits the possibility of switching to latex products. Another obstacle to this transition is that nitrile gloves are traditionally more tough, therefore it is much less convenient is when wearing in comparison with the same type of gloves, made of materials based on natural rubber latex. For example, examination gloves made of natural rubber latex (NRL) usually require a voltage of about 2.5 MPa (58 psi) for stretch to elongation of about 300% relative to the original dimensions. Often this is called a 300%modulus gloves. On the other hand, nitrile examination gloves, usually require increasing the specified voltage more than twice, about 5 MPa (116 psi)to achieve the same 300%strain. Another choice in favor of synthetic material is vinyl, but vinyl is considered as a material with a lower performance.
Currently on the market there are no proposals synthetic latex examination gloves, in which the ratio of the force - deformation would be close to the ratio of the force - deformation gloves from natural rubber, not to mention the fact that they had properties similar to or the same as the properties of the gloves on the basis of natural rubber in the same conditions. The ratio of the force - deformation related to the direct measurements in order to learn how to respond (stretchable) material in response to the applied force regardless of the thickness of the material. In contrast, the ratio is ia deformation - the effort to characterize the response to the applied force per unit cross-sectional area of the material.
Nitrile rubber, i.e. a synthetic polymer, is often used in emulsion (latex) for production of medical and industrial gloves, is a three-tier atactic copolymer of Acrylonitrile, butadiene and carboxylic acid, such as methylacrylate acid. It can be structured using two different mechanisms with the aim of improving its strength and chemical resistance. The first mechanism structuring (stitching) of the polymer is ion binding carboxyl groups with each other using ions of polyvalent metals. The presence of these ions usually provided by adding zinc oxide to the emulsion. As a rule, the strength and hardness/softness of the polymer is very sensitive to this type of cross-linking. The second mechanism structuring polymer is in the formation of covalent cross-links between the butadiene segments of the polymer with the use of sulfur and catalysts, known as accelerators of vulcanization of rubber. The formation of such cross-linking is particularly important for improving chemical resistance. Often the process of making gloves is that the first ceramic mold in the form of gloves on oat solution of coagulant, typically, calcium nitrate, and then the form is dipped in nitrile latex to cause local gilotinirovaniya nitrile rubber on the surface of the form.
Some previous attempts to mitigate the products of nitrile rubber included restrictive or even complete elimination of additives of zinc oxide and other materials that can lead to the formation in carboxypropanoyl nitrile rubber cross-linking ion mechanism (i.e. to sew it), such as that described in U.S. patent US 6031042 and 6451893. In addition to the fact that it does not provide interdependence of force and deformation, similar to that which occurs in the case of comparable products from natural rubber, this method results in a material with a lower strength, requires a higher temperature vulcanization requires extremely high consumption of other chemicals that can cause skin irritation, or it can lead to process upsets, such as thickening nitrile latex before dunking.
Other attempts to manufacture a more comfortable nitrile gloves, such as those described in US 5014362 and 6566435 based on stress relaxation over time and require constantly applied levels of deformation to cause the relaxation or softening. Such is right, it is difficult to maintain, and they can be unworkable in the real world practical application.
There is a need for the products of the polymer on the basis of nitrile, which can successfully combine the advantages of nitrile materials with greater flexibility or softness of natural rubber latex without the need to apply the conditions necessary for softening caused by relaxation of the tension. There is a need for this type of nitrile gloves, which may include polymer composition and dimensions of the product to simulate the comfort and softness inherent in the products made of natural rubber latex, but continue to be protective and not cause allergies properties of nitrile rubber. When wearing such gloves elastomeric material shows the profiles of physical strain or tension, similar to the profiles of natural rubber, but without any associated problems of natural rubber.
Brief description of the invention
The present invention relates to an elastomeric product of nitrile rubber, showing the interdependence of forces and deformations corresponding to a similar interdependence of the branch, Rubezhnoe, Ukraine rubber products, but keeping the values of ultimate tensile strength and protective properties of conventional nitrile rubber. In particular, izaberete the s describes a relatively thin elastic products such as the glove is thinner and more flexible or soft compared to conventional nitrile gloves, but designed to retain the protective properties and to maintain sufficient strength for work in industry or laboratory and to perform all medical procedures, in which the staff is usually nitrile gloves. A more subtle, soft nitrile" glove shows the characteristic response to deformation by an applied force to it, similar to the characteristics of gloves from natural (branch, Rubezhnoe, Ukraine) rubber.
The modulus nitrile material ranges from about 3 to 6 MPa, and the material can maintain the value of ultimate tensile strength in the range from about 30 or 32 MPa to 56 or 58 MPa. Although one of this range module in the standard glove thickness and sufficient to achieve the mechanical properties of natural rubber, however, reducing the thickness of the product in addition to reducing its module allows you to achieve the desired goal. While conventional nitrile examination gloves have a thickness of about 0.14±0.02 mm, nitrile gloves according to the present invention is thinner, the thickness is in the range of from about 0.05 mm to 0.10 or 0.11 mm, measured in the palm of the hand, a certain standard of American society for testing and materials (STM) D-412-98a (re-approved 2002).
According to the present invention is that by simultaneous control level fusion materials nitrile composition and the proper thickness of the product, both types of control are chosen to achieve maximum strength and minimum values of the force required to stretch the material, it is possible to obtain a material with the same characteristics of the response effort, as the thicker gloves made of natural latex. The crosslinking between the carboxyl groups is controlled by the number and types of ionic material added to a nitrile emulsion before it can be used to obtain macanova products. The thickness can be controlled by various means during the process of mikania.
The proposed invention allows for a more streamlined or standardized levels of chemicals and process parameters to achieve the maximum value of the strength potential of nitrile rubber and make the glove more flexible, and more comfortable to wear than conventional products made from nitrile. The proposed approach has the following advantages over the respective approaches of the prior art. The present invention allows to achieve good elasticity at all levels of crosslinking AG is new and provides a high rate of formation of covalent cross-links without the need of heating to high temperatures. The invention allows the use of traditional amount of cross-linking agents and accelerators without complications, which are often the result of too high or too low levels of these chemicals. Too low of a metal oxide, for example, can degrade the quality of the process gilotinirovaniya or may cause thickening at higher pH values (about 8.5 or higher).
This approach does not depend on the need of the stress-relaxation period of time of about 10 to 15 minutes, or from permanent deformation, so that the result of this relaxation, as it was described in other previous attempts, was more comfortable to wear a glove. Favorable deformation in response to applied force has proposed in the invention-based material nitrile rubber can be assessed directly by the user. A new type nitrile polymer can be modified to report them more flexible and provide more comfort to wear.
It is considered that the special properties proposed in the invention of "soft nitrile materials is partly due to the nature of the nitrile composition that includes a mixture of two taken in a ratio of about 50:50 Acrylonitrile compositions. On the one hand, the first nitrile composition softer or, in other words the AMI, has a lower module relative to the second nitrile composition. On the other hand, the second nitrile composition exhibits a higher molding properties in comparison with the first composition. The properties of each composition help to create the combined mixture, which improves the process of mikania and allows you to get a softer and more flexible material. Such a phenomenon rarely observed in technologies nitrile materials. The orientation or placement of carboxyl groups in the molecules nitrile polymer - either outside or inside - can influence the reactivity of carboxylic groups relative to cations such as magnesium or zinc.
In the present invention is also described in detail a cost-effective way or means for the production of such soft nitrile gloves. The method envisages preparation forms, application form coagulating the coating covering at least part of the surface form nitrile compositions, similar to the above, the vulcanization nitrile composition for formation of the substrate and removal of the nitrile substrate to form.
Additional characteristics and advantages of the present invention will be disclosed in the following detailed description. As the above summary, as well as the subsequent detailed description and examples are only on the I create a visual presentation and to facilitate the understanding of the essence of the claimed invention.
Brief description of drawings
1 shows the curves of load - deformation, showing the difference in the relative tensile strain caused by a wide range of voltages applied to the samples for gloves made from natural rubber latex, of the three conventional nitrile compositions, and chlorinated/non-chlorinated options nitrile compositions of the present invention;
figure 2 is a graph showing the relation between load and deformation for the same samples;
figure 3 on an enlarged scale graph of the load - deformation figure 2, showing the region between zero and 400% strain, and
figure 4 - illustrates the load required to fracture the specimen during testing in accordance with ASTM D-412-98a. Shows the range and average values.
Detailed description of the invention
The present invention describes the creation of the nitrile polymer compositions elastic articles, such as gloves, having physical characteristics similar to the characteristics of similar products made of natural rubber latex. A necessary property of elastomeric products worn on the body, is the softness or flexibility of the polymer material. The invention describes the use of rubber compositions based on nitrile for manufacturing products, is within high physical durability and chemical resistance and different at higher softness (that is, having a lower modulus of elasticity) from many of the previous nitrile rubber compositions. Used herein, the term "elastic" or "elastomeric" refers in General to a material which, upon application of force, can stretch to a stretched, biased length. Upon termination of stretching, displacing forces the material is restored essentially to its own form or the original size or alternatively at least about 50% deformed or stretched dimensions. Used herein, the term "tensile-elongation" refers to the total amount or percentage by which an elastomeric substance or membrane stretched or extended beyond its original size. "Interest deformation" or "percent elongation" can be determined according to the following formula:
Final size - the Initial size/Initial size × 100.
Alternative total elongation can be described in terms of comparing the stretched length of the unstretched length. Total value reduction (contraction after termination of force), however, is the ratio of pulling to the difference between the stretched and unstretched lengths. Although this approach is not consistent, but it is common. For example, only as an illustration, an elastic material having an unstretched length (i.e. the length in the relaxed state) 10 cm, can be onlineno least up to 13.5 cm by application of tensile or bias force. Upon termination of tensile or bias force of the elastic material is recovered to a length not more than about 12 see
Traditionally used two methods to create a softer, more flexible elastomer articles. One method involves making the epigastric or membrane walls of the product thinner. The second method provides for the reduction of modulus of elasticity of the elastomeric material. Each of these two approaches combines the advantages and disadvantages. Such as gloves and condoms thinner polymer membrane allows the user to experience a greater tactile sensitivity. Exactly the same often than become thinner wall elastic polymer material, the less force required for bending, stretching or deformation of the product. Subtlety, however, may often be accompanied by problems such as low tensile strength tensile or a tendency to break during use. A lower modulus of elasticity, or young's modulus, on the other hand, maintains a relatively thicker substrate and nevertheless to ensure ease of bending while wearing it. The reduction module rubber composition by reducing the degree of crosslinking in the polymer often results in lower tensile strength or the more low chemical resistance.
The behavior of the proposed invention nitrile gloves in respect of their response to the impact force, as a rule, is very different from the behavior of similar gloves from natural rubber. When both types of materials are attached equal force, the total value of the instantaneous stretching significantly greater gloves of natural rubber. Although this difference can be reduced by various techniques, of which the most typical are such techniques as reducing the degree of crosslinking occurring under the action of oxides of metals, or even complete exception, however, the reduction of oxides of metals to the extreme level needed to close a relatively large gap in the difference between the two types of polymers, often irreversibly compromise the strength properties of the material, or such a method has an undesirable impact on the manufacturing process by Makane (i.e. slows down the gelatinization, slows the formation of covalent cross-linking increases the viscosity and so on), and while still not achieved full simulation characteristics in relation to the response to the applied force, which can be observed in natural rubber.
According to the present invention, the degree or the number and types of the resulting ionic cross-linking can is about control by regulating the content of all ionic materials during mixing or compositions of nitrile latex. However, instead of striving to extreme high or low level of control, we have found a balance in the composition, which can provide a sufficiently high tensile strength to reduce the thickness of the desert products, finding such thickness that it required less effort to stretch in comparison with the currently used synthetic products. Controlling both the level of cross-linking in the composition of the material and the proper thickness of the substrate for the product to maximize the strength of the material and to minimize the amount of force needed to stretch the material, it is possible to obtain a material whose behavior in terms of response to acting on his strength will be similar to the behavior of the substrate made of natural rubber latex with similar or greater thickness. By crosslinking the carboxyl groups are managed using the number and types of ionic material added to a nitrile emulsion before it can be used to obtain machaneh products. The thickness of the product can be controlled by a variety of techniques during the process of makanya, such as the manipulation of the duration of time during which the form is dipped into the emulsion or coated with emulsion, temperature or mechanical the rotation, or turn shape after it has been removed from makatulog baths.
Gloves are manufactured using the present invention, are less bulky and more flexible in the toe, therefore, provide a greater comfort compared to conventional nitrile gloves and, in addition, they can reduce costs in the process of their production and ultimately reduce costs for the consumer. In thinner gloves on their media also has a great tactile sensitivity in the hand and the fingertips in comparison with conventional gloves. All these advantages can be realized without compromising tensile strength of gloves.
A large part of examination gloves of nitrile rubber, currently available on the market, have a thickness in the range from about 0.12 to 0.13 mm or more. In accordance with the present invention can be obtained gloves with less weight basis compared to conventional gloves. Glove made in accordance with the present invention, has a thickness in the Palmar portion within about 0.05 to 0.10 mm, it does not deteriorate the strength characteristics inherent in a thicker gloves with more weight basis. Although nitrile gloves manufactured in accordance with the present invention, on average, 30-50% thinner than other nitrile shows the e gloves, currently available on the market, gloves according to the invention are designed so that they have sufficient strength to withstand loads during industrial, laboratory or medical procedures, under which staff usually wears gloves. Browse many nitrile examination gloves, currently available on the market, shows that the thickness of the Palmar part is about 0.12 mm or more.
Exact measurement point is a point, specified by the American society for testing and materials (ASTM) standard test D-412-98a (re-approved 2002) "Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers-Tension", published in January 2003, the content of which is incorporated into the present application by reference. These test methods provide procedures used for evaluation of tensile properties in the vulcanized rubber and thermoplastic elastomers. Determination of tensile properties begins with the selection of test pieces from the reference material and includes specimen preparation and testing of samples. Samples can be in the form of a dumbbell, ring or straight pieces with a uniform cross-sectional area. Measurement of tensile stress, tensile stress at a given relative elongation, ultimate tensile strength, limit the uchesti and relative elongation at break are performed on the samples, which have not been pre-stretched. Tensile stress, ultimate tensile strength and yield strength are determined on the basis of the original area of uniform cross-sectional sample. The set of measurements, including the elongation of the sample is performed once in accordance with the prescribed procedure pre-relaxed sample was stretched and then released, so that it again stanols.
Section I (composition)
Carboxypropanoyl nitrile, representing three polymer of the monomers butadiene, Acrylonitrile, and organic acids that has at least two properties that make it useful for the manufacture of elastomeric products. These two characteristics are high strength and impermeability to certain hydrocarbon solvents and oils. The compounding and vulcanization of rubber (which is used in the form of a latex, for example, to makanya order to obtain industrial products, such as gloves or condoms) with other ingredients, such as vulcanization agents, accelerators and activators, in the General case is to optimize these properties. The level of each monomer in the polymer and the degree of vulcanization determine the strength and chemical resistance of the finished product. Polymers with higher levels is crylonitrile, as a rule, have a higher resistance to aliphatic oils and solvents, but, on the other hand, they are more rigid than the polymer, in which the levels of Acrylonitrile below. Although the chemical stability of the polymer and is determined to some extent by the chemical nature of the monomers from which the polymer is, however, when polymer molecules undergo chemical crosslinking, its resistance to chemical swelling, permeability and dissolution increases.
Crosslinking also increases the strength and elasticity of rubber. Carboxypropanoyl nitrile latex can be chemically cross-linked at least two ways: butadiene subunit (subgroups) can be crosslinked systems sulfur/accelerator with the formation of covalent bonds and karboksilirovanie (organic acids) centers can be sewn oxides or salts of metals with the formation of ionic bonds. Sulfur cross-links often contribute to a significant improvement in oil - and chemical resistance. The result of the formation of ionic cross-linkages formed, for example, when added to the latex of zinc oxide is high tensile strength, high resistance to puncture and high resistance to abrasion and high elasticity modulus (a measure of the force required to stretch the film of rubber), but bad butter - and Himicheskaya resistance. Many of the present rubber composition, typically use a combination of the two mechanisms vulcanization. For example, manufacturers carboxylating nitrile latex is often recommended to add, in combination with sulphur and accelerators, from 1 to 10 parts of zinc oxide per 100 parts of rubber.
Unlike some of the ways of making more soft nitrile gloves, described, for example, in U.S. patents US 6031042 and 6451893, each of which includes a composition that does not contain zinc oxide, the present invention provides the composition with zinc oxide, which improves the quality of the process makanya and speed of vulcanization. If zinc oxide is not used, the vulcanization time required to achieve an optimal state of vulcanization, can be significantly longer, and vulcanization is significantly less effective. This means that the cross-ties will be longer (more sulfur atoms on one cross-link), and a greater amount of sulfur will not participate in the process of cross-linking of polymer chains. In the vulcanization of rubber may be less effective, and vulcanized so the rubber will have a lower resistance and a lower chemical resistance. Ionic cross-linking, however, often increases the rigidity of the product, made of couch is CA. This is a disadvantage in the case of applications where you want a softer rubber. For example, surgical gloves, made of soft rubber, can provide medium gloves higher tactile sensitivity, which is desirable for the surgeon's point of view probing fingers of the patient's body during surgery and prevent hand fatigue.
More comfortable nitrile glove, easier stretchable, that is, having a lower young's modulus, can be manufactured using a polymer containing less than Acrylonitrile, or polymer, structured to a lesser extent. However, these modifications often reduce the strength, chemical resistance, or both together, and the result is a product unsuitable for many applications. Conversely, highly desirable is a soft rubber having a tensile strength and chemical resistance, corresponding to those more hard rubbers.
Rubber membrane according to the present invention is more elastic; thus, it was found that individuals who usually have to wear gloves large size, can use gloves medium size, made of the proposed in the present invention compositions on the basis of nitrile, without binding or loss of comfort flexibility. Moreover, Bo is its thin rubber membrane increases tactile sensitivity to temperature and texture of the surface.
Not wishing to be bound by theory, one can assume that the matrix structure and strength proposed in the present invention products, possibly due to the interaction of all those present in the system of ions, in particular two - or polyvalent cations with carboxyl components of the polymer matrix. Divalent or multivalent cations, such as Mg, Ca, Zn, si, Ti, Cd, Al, Fe, Co, Cr, Mn and Pb, can be crosslinked with carboxylic groups are ionized carboxylic acids, forming a relatively stable cross-links. Of these preferred cations are Mg, Ca, Zn, cu or Cd. Preferably, methylacrylate monomers were located relatively close to each other in the polymer matrix structure, so that the divalent or multivalent cation could be crosslinked with two or more nearby links. The positive charge of the cation may well balance the negative charges of the electrons carboxylic acid groups. It is believed that in the absence of divalent or multivalent cations in the polymer chain in nitrile emulsions are not well fastened to each other by multiple bonds. Monovalent ions such as K, Na or H, which do not have sufficient electronic power to establish communication with the second methylacridinium link can assume b is more weak kinds of associative links. Monovalent salts, which increase the pH of the system, can also contribute to swelling of latex particles, which leads to more carboxyl groups is made available to other cross-linking agents. The positive charge of the cation may well balance the negative charges of the electrons carboxylic acid groups.
In addition to a slight decrease in, for example, the content of zinc oxide in the composition, it was found that the addition of large quantities of monovalent ions have a beneficial effect on the maintenance of a high strength material. These monovalent ions can come from alkaline agents used to adjust the pH of the composition, or from other salts, which do not destabilize nitrile latex. Included a combination of sulfur and rubber accelerator for messages required level of chemical resistance to the finished product. In some cases, add enough with the grey one dithiocarbamate accelerator; in other cases, which require higher levels of chemical resistance, the best results are obtained by the combination of diphenylguanidine, tinkertaylorsoldier and dithiocarbamate accelerator with gray.
The main polymer used in the present invention nitrile material is a three-tier polymer composition containing AK is elontril, butadiene and carboxylic components. You can put that special positive properties of soft nitrile materials according to the invention derives in part from the nature and interaction of a mixture of Acrylonitrile components in the composition. The mixture comprises two first and second compositions comprising, taken in the proportion of 60:40 to 40:60. Mix the components together has a synergistic effect, helping to give a softer and more flexible material, which also detects the higher characteristics of the process makanya. Such a phenomenon rarely observed in technologies nitrile materials. The orientation or placement of carboxyl groups in the molecules nitrile polymer - either outside or inside - can influence the reactivity of the carboxyl groups in relation to ions of zinc; therefore, it can be assumed that some of the components responsible for softer, due to the low modulus, properties, while others are responsible for a good film-forming properties.
The content of Acrylonitrile in a mixed or combined composition is from about 17 to about 45% (wt.), preferably from 20 to 40% and more preferably from 20 to 35%. Typically, the content of Acrylonitrile is in the range from about 22 to 28% (wt.), the content of methacrylic acid for example is t less than 10%, and the residue in the polymer falls in butadiene. The content of methacrylic acid should be maintained below about 15% (wt.), preferably about 10%, and the balance in the polymer falls in butadiene. The basic three-tier polymer is obtained in the emulsion polymerization process and can be used while it is in the form of an emulsion, for the manufacture of gloves or other elastomeric products.
Composition Acrylonitrile polymer suitable for use in the present invention may have a glass transition temperature (Tg) the range of about -15°C or -16°C to -29°C or -30°C under normal conditions. In some embodiments, performing the preferred Acrylonitrile polymer compositions, such as PolymerLatex X-1133 or Synthomer 6311 supplied to the market accordingly firms PolymerLatex GmbH and Synthomer Ltd., have a temperature Tgglass transition in the range from about -18°C to -26°C. More preferred are nitrile composition, such as Nantex 635t, commercially available from the company Nantex Industry Co., Ltd. (Taiwan, R.O.C.), where Tgis within about -23,4°C to -25,5°C. This nitrile composition can provide a higher tensile strength in comparison with other commercially available nitrile polymers.
Reducing the thickness of the membrane or membranes of the substrate tends to decrease durable the particular elastomeric gloves. To offer in the invention, the glove was thinner and have high strength properties, was developed nitrile polymer having a higher own strength in comparison with other nitrile latexes available on the market. These are associated with the strength benefits were optimized using the present compositions and methods of compounding. To optimize the strength properties of the gloves is preferable that pH had a relatively high value, for example in the range from about 9 to 12.5 or 13. Especially preferable that the pH value was in the range of from about 10 to 11.5. The pH value of the emulsion containing Acrylonitrile polymer, can be brought to the optimum values by conventional means, for example by adding potassium hydroxide or ammonium hydroxide in a concentration of from 5 to 10%.
Nitrile emulsion compounding or combined with other chemical products, performing a supporting role in the formation gloves and reporting gloves of sufficient strength and durability for use in accordance with their intended purpose. Compounding thinner gloves is performed by combining the following materials. Below is a generalized formula for this approach, including all components, given in approximate parts per 100 parts of the su is rubber:
|Carboxypropanoyl nitrile latex||100 dry parts|
|The hydroxide of alkaline metal||0÷1,5|
|Zinc oxide or the oxide of another metal||0,5÷1,5|
Can be used any carboxypropanoyl "nitrile", i.e. butadiene-nitrile rubber, available in the form of latex, which can be suitable for makanya. This formula can be adjusted within some of the values to compensate for different private properties inherent in many of the available nitrile latexes. As some suitable examples nitrile latex Synthomer 6311, manufactured by Synthomer Sdn Bhd., or Perbunan N Latex X-1133, manufactured by PolymerLatex GmbH. Titanium dioxide is used only for message to the desired level of whiteness is whether opacity.
In some examples of embodiments of the present invention, a commercial solution of nitrile latex, as it was received, had a total solids content of (CTV) is about to 43.5%. Proposed in the present invention nitrile emulsion mixture can be prepared with CTV about 15 or 16 to 25%. In some preferred versions of the value properties may be about 19 to 22%. Stay glove form into a latex bath is determined depending on the strength of coagulant; however, this time can be changed while making a thin gloves. The finished glove is STV equal to 100%, because the substrate must not contain appreciable or significant quantities of water.
It is believed, however, that the properties of butadiene-nitrile polymer is not due to material components, but depend on the structure of the polymer, which, in turn, is determined by the conditions of polymerization. The properties of the polymer exposed to the strong influence of the polymer structure. The molecular structure of the polymers can be very complex, with the possibility of changing the molecular weight, molecular weight distribution, branching, degree of structure during the polymerization, with the possibility of many types of chemical compounds for diene monomers, etc. When several types of monomers are combined in the floor of the measures such as carboxypropanoyl butadiene-Acrylonitrile polymer used in glove manufacture, the structure becomes even more complex. The total content of each type of monomer and the sequence of monomer units also contribute to the properties of the obtained polymer. When repetitive structure of monomer units randomly, as is the case in the nitrile rubber used for gloves, on the physical properties of the polymer have a greater impact linearity (as opposed to branching of the polymer and the molecular weight and less influenced by the properties of homopolymer. This is because the properties expected from a regularly repeating structure of the polymer obtained only from a single monomer, change every time when there is a break repetitive patterns or any other change in the result of adding other types of monomer units. The high content of each monomer is likely to increase the likelihood that the properties expected from homopolymer derived from this monomer, will contribute to a General characterization of the properties of the polymer due to the increased affinity of repeating structures.
In carboxypropanoyl nitrile polymer used in the manufacture of thin gloves, Acrylonitrile and carboxylic acids is, which generally account for about 35% polymer add the polymer to a degree of plasticity in relation to the properties of elasticity, residual stresses and stress relaxation. They also prevent regular recurring CIS-1,4-structure, which would convey the polybutadiene its high elasticity and lowest residual strain/stress relaxation.
In the most General description of such carboxypropanoyl nitrile rubber is a long chain of randomly distributed therein three Monomeric components with branching and cross-stitching. These branched, random three polymers are molded into tiny discrete particles, which are emulsified in water. In addition, the polymer structure, in the final shaping properties of the glove also plays a role and its structure in the form of particles. Parameters such as particle size, distribution of particle size, the level of agglomeration of the particles, the density of the particles, etc. have an impact on how the molded product, and also ultimately affect the properties.
In the present invention the polymeric structure includes three random polymer (as opposed to block or alternating three-tier polymer) of Acrylonitrile, butadiene and carboxylic acid. Properties depend on the average molecular weight, molecular-mA the spot distribution, linearity or degree of branching, the content of the gel (crosslinking during polymerization) and microstructure (which monomer units are next to each other in short periods of polymer chain).
Fine tuning proposed in the present invention composition can be lowered by 300 percent modulus nitrile gloves to about 3.5 MPa, but the result of this configuration will only nitrile glove, requiring more force to stretch (strain) of the material in comparison with a glove made of natural rubber latex. To stretch nitrile gloves to about 400% of its original size, you may need a relatively small force, up to about 3.5 Newton (N). Preferred is a force less than or equal to about 2.5 N.
As the ultimate tensile stress (i.e. the stress required to fracture a material for gloves, manufactured using the above composition, substantially higher than the tensile strength of conventional gloves from natural rubber, reducing the thickness of the gloves in combination with low module will allow you to obtain a nitrile glove with a ratio of force-deformation, very close to that of gloves from natural rubber latex (NRL). The combination of low-modulus vulcanizing system properly with the m selection of the thickness of the gloves allowed to obtain nitrile elastomeric glove having the same characteristics by the ratio of the force-deformation as substrates made of natural rubber latex. In other words, when the same force is applied to the glove according to the invention and to the glove made of natural rubber latex, each glove demonstrates a similar elongation; therefore, both types of gloves would have similar characteristics of comfort while wearing them.
Section II (strength)
While the proposed nitrile gloves manufactured in accordance with the present invention, on average, 30-40% thinner gloves made of other compositions nitrile material currently available on the market, we offer gloves have sufficient strength for use in industry and in the laboratory or during all medical procedures, usually performed in such gloves. Browse many nitrile examination gloves, currently available on the market, shows that the thickness of the palm area is about 0.12 mm or more. Settings and measurement protocols defined by the standard American society for testing and materials (ASTM) D-412-98a. In the present invention the ASTM Protocol used without any changes.
The tests were performed on the Instron strain gauge®, model 5564, with a static load cell capacity of about +/-100 N and extension the PoE XL. For testing can also be used in other similar types of equipment, provided that the machine meets the requirements of ASTM standard.
As already mentioned, the thickness of many of nitrile examination gloves, currently available on the market, is about 0.12 mm or more. In accordance with the present invention can be manufactured nitrile gloves, having a lower basis weight than conventional gloves. Glove according to the present invention has a thickness in the Palmar part within the limits of from about 0.06 to 0.10 mm, without compromising strength characteristics, which usually have thicker gloves with more weight basis. Used in this description, the term "strength" can be defined as a function of total effort required to fracture a specimen of prescribed shape and size, such as the samples used for the test standard D-412 ASTM. When testing the glove according to the invention with a thickness of from about 0.08 to 0.10 mm in the palm of the hand showed the average breaking strength in the range of about 8.7 to 10.2 Newton (N), preferably from 9.1 to 9.85 H and more preferably from 9,18 to 9.5 H. Gloves offered currently on the market have values in the range of about 6.7 to 14.3 H, most of the values from 7.5 to 10.5 N.
Nitrile material elastic pen is ADI may have a tensile strength at break in the range from about 30 MPa to 55 MPa, preferably about 40 MPa. Usually the elongation at break is in the range from about 550 to 750%, preferably approximately 650%. At 300% elongation-the elongation modulus nitrile material is in the range from about 3 MPa to 6 MPa, preferably of approximately 4 MPa.
In order to achieve the specified module content of ionic materials in the composition regulate. If you want to make a very fine product, for example a thickness of 0.05 mm, the allowable is higher modulus, because the small thickness of the material is still relatively less force is required to stretch the product. In this case, the metal oxide could be used in an amount corresponding to the upper value of the specified interval, together with low to medium level (0-0,5 parts per 100 parts of rubber) of a hydroxide of an alkali metal or another monovalent salt. This would provide the finest products of sufficiently high tensile strength and high breaking stress values.
If you want to produce products with the upper value of the thickness of interval (from 0.10 to 0.12 mm), discussed in connection with the present invention, it is possible to choose lower levels of the metal oxide together with low to medium levels (0.5 to 1.5 parts per 100 parts of rubber) of a hydroxide of alkaline is on metal. The specific examples of such compositions are given in table 1.
|Carboxypropanoyl nitrile latex||100||100||100||100|
|The ammonium hydroxide||0,4||0,0||0,0||0,78|
|The potassium hydroxide||0,0||1,45||1,0||0,0|
|The zinc diethyldithiocarbamate||1,0||1,0||1,0||1,0|
|The obtained properties|
|300%modulus (MPa)||6,2||3,6||the 4.7||6,3|
|Tensile strength (MPa)||to 43.1||35,0||50,0||50,3|
|Destructive force at a thickness of 0.05 mm (H)||6,5||5,2||7,5||7,5|
|Destructive force at a thickness of 0.10 mm (H)||13,0||10,4||15,0||15,0|
|Effort for education 300%deformation (thickness 0.05 mm) (N)||0,9||0,5||07||0,9|
|Effort for education 300%strain (at a thickness of 0.10 mm (H)||1,8||1,0||1,4||1,8|
Similar properties for samples cut from commercially available gloves made of natural rubber latex of normal thickness (0.15 mm) and commercially available nitrile examination gloves with a thickness of 0.12 mm (both gloves are manufactured by Kimberly-Clark Corporation), are shown in table 2.
|Breaking force (N)||the 10.1||9,6|
|Effort for education|
If any of the above examples, the compositions will be required thickness is above 0.05 mm so that the force required to fracture gloves made of them corresponded to the force required to fracture natural latex examination gloves, manufactured at the present time the company is Kimberly-Clark. Although the amount of metal oxide as a crosslinking agent in the composition can be slightly adjusted downward, in order to have a lower module, however, strongly reduce this number it is not necessary nor desirable, since high strength, which is achieved with the help of these cross-linking agents, allows to obtain a product with sufficient strength when the thickness is smaller. Given that the desired force is directly proportional to the thickness of the gloves, the thickness, which is necessary for these compositions to be destructive force, equal to 10.1 N would be 0,078, 0,097, 0,067 and 0,067 mm, respectively, for examples a, b, C and D. the Corresponding force required to stretch these materials up to 300%elongation, based on these thicknesses would be 1,4; 1,0; 0,9 and 1,2 Newton. Although the examination glove made from the composition at a thickness 0,067 mm, would give the property is extremely close to the properties of a typical examination gloves made from natural latex, you can see that all these compositions can be used for the manufacture of gloves with properties similar to the properties of gloves from natural rubber.
It is believed that the combination of a lesser thickness of the substrate material used nitrile composition, higher pH (≥8.5 or 9) and change the procedures for compounding and makagiansar contribute in significant differences between the production of gloves according to the present invention and the production of other currently available nitrile examination gloves.
The accompanying drawings are graphs and charts comparing 1) gloves made in accordance with the present invention, 2) commercially available nitrile gloves at the base, made of Kimberly-Clark Safeskin®, and 3) other comparative examples. The graphs in figure 1 and 2 show the range of values for tension and destructive efforts. The present invention differs from other products on nitrile basis to those that read directly from the instrument readings effort similar to the testimony of the same parameters for gloves made from natural rubber. It can be assumed that this phenomenon is derived from the combination of modifications module with a relative thickness of the products of the present invention. In the General case, soft nitrile products have a much lower modulus than the modulus of competing with them modern powder-free nitrile gloves. This synergistic effect of reduction in thickness and maintaining a high tensile strength is an additional sign, which gives the uniqueness of the present invention.
Figure 1 presents a graph which compares the characteristics of different examples glove membranes made according to the present invention, nitrile rubber materials basis, currently available on the market, and natural the CSOs rubber latex. Experimental examples according to the present invention is indicated by EXP 1 and EXP 2, and comparative examples are symbols of the OMRS and OMRS Century Standard nitrile designated as a SUFFIX, and natural rubber latex - like LATEX. The graph illustrates that the voltage required to deform (module) gloves made of the composition proposed in the present invention, compared with the stresses of modern examination gloves to nitrile basis. However, for full playback examination gloves made of natural rubber latex such as the interdependence of stress and strain, it is necessary to further decrease the voltage level of the material according to the invention.
Figure 2 shows that reducing the relative thickness nitrile gloves, made according to the invention, without the risk of reducing their barrier properties or properties elongation, response to the applied force (elastic-plastic behavior) such gloves can closely approximate or simulate the characteristics of natural rubber gloves, particularly when strains up to 300% or 400%, which is the normal tensile strain, which would be expected in donning and wearing examination gloves. To stretch up to 500%relative elongation gloves, izgotovlenie of the compositions, proposed in the present invention, can be stretched when the force is less than 2-3 Newtons (N), while comparative examples require to do this about 4 Newtons or greater. In order more clearly to illustrate the advantages of the invention, figure 3 presents a magnified nizkotemperaturnyi curves force - deformation at a relative elongation of 400%.
The thickness nitrile gloves according to the invention ranged from about 0.07 to 0.10 mm, preferably comprised of about 0.08 mm in the Palmar region. The thickness of the samples of natural rubber was about 0.15 mm, the thickness of the comparative nitrile gloves from Kimberly-Clark and two other manufacturers was from 0.12 to 0.13 mm
To illustrate the unique properties obtained through the present invention, in the drawings included data on two different soft-nitrile experimental products, one - chlorinated (EXP 1) and other chlorine-free sample (EXP 2). Non-chlorinated glove had characteristics typical of powdered gloves or gloves, polymer coated. Chlorination and floor are standard methods to eliminate the need for dusting gloves. Label NR and SUFFIX refer to the gloves of the PTF (natural rubber latex) and PFN (NBR latex), produced at present is W hen a Corporation Kimberly-Clark. For comparison, also included two other nitrile gloves from competitors (comparative examples a and b).
Figure 4 shows the force required to fracture the samples shown in the previous graphs. Given the range and average values for the efforts. As explained above, the force required to fracture the samples fabricated using the present invention can be adjusted by adjusting the content of ingredients in the composition or by the exact determination of the thickness of the gloves. Usually the membranes made of natural rubber polymers, have a point of destruction about 10 N. In contrast, value-destroying efforts from various iterations of the composition according to the present invention, can be 15 N or higher while maintaining the thickness of the gloves less than about 0,10 mm
Other advantages of the present invention, in comparison with traditional nitrile or gently-nitrile compositions, include, for example, their suitability to create a substrate that is thinner than other nitrile examination gloves, while maintaining high strength and chemical resistance, comparable with the resistance of thicker gloves. Subtlety gloves can enhance tactile sensitivity, increase comfort (thin glove with low module). GP the wasps value can also be resolved in favor of the consumer. Thinner glove conducive to lower costs for its production due to lower demand in the material in comparison with thicker gloves. In addition, for example, in the standard wydanie the device can be Packed around 150 gloves instead of 100 with less packaging material.
Section III (processing).
It was found that the order in which chemical reagents are introduced into the composition, may be of great importance. The correct order and add proper quantity of reacting materials can provide higher technological and physical properties of nitrile material. The strength of nitrile examination gloves is usually achieved by ionic crosslinking of organic acid groups contained in the polymer structure. These chemical groups can interact with a variety of cations in the system. Some cations are already in nitrile emulsion at the time of its receipt is counterions for anionic surfactants used for the preparation of the emulsion, and the cations introduced to regulate the pH during production to ensure product stability during transport. Other cations can pass through the system with material added to a nitrile emulsion, for example, zinc ions get into it and the zinc oxide, and potassium ions or ammonium fall during the procedures regulating the pH to the desired value.
Adding a base, such as potassium hydroxide or ammonium hydroxide, after all other reagents sequentially introduced into the mixture, increases the strength of the substrate material, allowing the zinc from zinc oxide more vigorously react with the acid groups of the nitrile polymer, before the level of other cations in the system will increase significantly while regulating the pH. Also the result of this procedure is a glove that is able to more easily stretch that can be seen on the readings, measuring force for a specific, prescribed values of tension or measuring module, which represents the force per unit cross-sectional area at exactly a certain level of tension.
Table 3 contains a summary and comparison of certain physical properties for a number of examples of gloves. In particular, the properties include the force (Newtons)required to stretch the elastic shell gloves to about 400% of its original size, force (Newtons)required to stretch before breaking gloves, and relative thickness of each sample. Values of physical quantities for typical gloves made of natural rubber latex described in the quality control. In examples 112 presents butadiene-Acrylonitrile samples of gloves according to the present invention. Comparative examples 1-8 are typical examples of commercially available gloves to nitrile basis.
|Example gloves #||Force (N) at 400%elongation||Breaking force (N)||Thickness (mm)|
|Natural rubber latex (NRL) control||1,3||the 10.1||0,155|
|Example 2||1,7||which 9.22||0,09|
|Example 4||1,9||9.28 are||0,08|
|Example 5||2,0||to 9.32||0,08|
|Example 7||2,1||at 11.25||0,12|
|Example 10||1,8||a 9.25||0,09|
|Comparative example (powder-free polymer) 1||6,0||8,2||0,12|
|Comparative example 2||6,8||8,9||0,13|
|Comparative example 3||6,6||9,5||0,15|
|Comparative example 4||7,6||at 7.55||0,14|
|Comparative example 5||8,0||10,3||0,12|
|Comparative example 6||5,3||14,3||0,12|
|Comparative example 7||8,4||13,5||0,12|
|Comparative example 8||4,2||6,7||0,13|
As you can see, for examples according to the present invention it is necessary to apply only a part (for example, about from1/2to1/4the efforts at 400%elongation, which is required to make in eight comparative examples to achieve the same level of tension. This suggests that the present invention allows to obtain a softer and more elastic shell with stretch, more closely resembling the elongation characteristic of natural rubber latex.
The present invention may be useful in the technological process of manufacturing elastomer the x products composed of polyacrylonitrile materials. The invention enables to manufacture products on nitrile-based, closely reproducing the physical properties of elastomeric products derived from natural rubber latex. The invention can be successfully used in the production of a wide range of products such as medical examination and surgical gloves, condoms, caps for probes, thin protective dental strip, rubber fingertips, catheters and the like.
The present invention is described, both in General and in detail by examples. Specialists in this field will understand that the invention is not limited to only the disclosed specific variants of its implementation. It allows various modifications and variations, without going beyond the scope of the claims stated in the following claims, or their equivalents, including components equivalents that are currently known or that may be developed in the future and which could be used within the scope of the present invention. Thus, if in other respects, the changes are not beyond the scope of the present invention, these changes should be understood as included therein.
A. Forming gloves
In the production process nitrile gloves the content of solid substances is in nitrile emulsion reduced from 40-45% to about 23% for the thickness control gloves. To further reduce the thickness of the gloves, the solids content of even lower to about 20%. Thinner glove in accordance with the present invention can be manufactured by coating a coagulant in the process of mikania. This process or method provides for the preparation of pure glove form or mandrel, which is pre-heated to about 55-60°C., preferably up to 58°C. the Prepared form was dipping in an aqueous solution of calcium nitrate. The form, with the coagulant on the surface, dried, and again heated to 70±5°C, and then immersed in a bath with a compounded nitrile emulsion, forming gelatinizing glove. Top cuff can be rolled up edges. Form gelatinizing the glove substrate is soaked in water to remove all soluble components of the material. Form gelatinizing glove is dried in ovens at a temperature in the range from about 80°C. to less than 100°C. then When the form gelatinizing the glove substrate is heated to a higher temperature, the sulfur reacts with other chemicals and produces stitching links methylacrylate acid nitrile polymer. After the glove is removed from the form and surface of the glove is treated with chlorinated water to reduce stickiness. Finally, the glove is dried and otomat for packing.
Faster introduction of the glove form in nitrile emulsion and faster removing it from the emulsion can provide a more uniform thickness profile gloves, by reducing the difference in time finger and lip zones glove form compounded nitrile emulsion. Glove shape can be extracted from makatulog baths in the initial vertical, or near vertical position and raised for a short period of time from several seconds to about 40 seconds so that the fingertips were placed horizontally or were above the horizontal (for example, would be located above the horizontal with a slope to it about 20 to 45°). Then quickly lowered the tips of the fingers to the position or angle between the horizontal and the initial vertical turning shape along its longitudinal axis. Steps for raising and lowering can be repeated in a sinusoidal or wave-like movement. This process allows the nitrile to be distributed more evenly in form, resulting in a product with a thinner substrate.
Another symptom of thinner gloves of the present invention is chemical resistance, equal chemical resistance available on the market thicker nitrile examination gloves. This chemical resistant gloves are available which is a result of the use for the manufacture of a particular combination of vulcanization accelerators. This combination includes connection dithiocarbamate, Tizol and guanidine, which are present in the composition in an optimal ratio of about 1:1:2 respectively. In particular, according to one example embodiment of the invention, these compounds are diphenylguanidine (FGD), cancerchemotherapy (ZMBT) and zinc diethyldithiocarbamate (ZDEC), when the content of FGD about 0.5 parts per 100 parts of polymer, CMBT about 0.25 part per 100 parts of polymer and CDAC about 0.25 part per 100 parts of polymer.
This combination of accelerators is very similar to the combination described in U.S. patent US 6828387, which is included in the present description by reference, although the content of these chemical compounds are reduced by about 50%. Specified prior patent relates to the vulcanization of the composition of polyisoprene rubber. It is believed that unlike patent 6828387, in the present invention is a process of double stitching. In other words, in the case polyisoprenoid materials stitching is carried out using covalent double bond in the molecule of isoprene, while in the system on nitrile basis in accordance with the present invention, the stitching includes covalent interaction with the butadiene component and ion interaction with zinc oxide and a carboxyl group methylacrylate acid.
The present invention can be Polenov technological process of manufacture of elastomeric products, composed of polyacrylonitrile materials. The invention enables to manufacture products on nitrile-based, closely reproducing the physical properties of elastomeric products derived from natural rubber latex without due to latex protein-related problems allergic reactions. The invention can be successfully used in the production of a wide range of products such as medical examination and surgical gloves, condoms, caps for probes, thin protective dental strip, rubber fingertips, catheters and the like.
The present invention is described, both in General and in detail by examples. A person having the necessary qualifications and experience in this field will understand that the invention is not limited to only the disclosed specific examples of its embodiment. It allows various modifications and variations, without going beyond the scope of the claims stated in the following claims, or their equivalents, including components equivalents that are currently known or that may be developed in the future and which could be used within the scope of the present invention. Thus, if in other respects, the changes are not beyond the scope of the present invention, these changes should be understood as included therein.p> 1. An elastomeric article formed from carboxypropanoyl butadiene-nitrile rubber composition in latex form, which includes two first and second acrylic-nitrile composition comprising, taken in the proportion of 60:40 to 40:60, and has a glass transition temperature Tgin the range from -15 to -30°C, and a proportionate amount of alkali metal hydroxide and a metal oxide, where the number of alkali metal hydroxide is 0-1,5 parts per 100 dry parts of rubber, and the amount of metal oxide is greater than 0.5 but less than or equal to 1.5 parts per 100 dry parts of rubber, and the product has a given thickness of up to 0.12 mm
2. The elastomeric article according to claim 1, where this rubber composition has a content of Acrylonitrile in the range from 17 to 45 wt.%, and the content of the carboxylic acid of up to 15 wt.%, and the remainder of the rubber composition is butadiene.
3. The elastomeric article according to claim 1, where the alkali metal hydroxide is present in such quantity that the rubber composition has a pH of 8.5 or more in the process of formation of the product.
4. The elastomeric article according to claim 2, where this rubber composition also includes a stabilizer and one or more accelerators from the group comprising guanidine, dithiocarbamate and, if necessary, the connection of the thiazole.
5. The elastomeric article according to claim 4,where the specified composition accelerators includes: zinc diethyldithiocarbamate (ZDEC), zinc-2-mercaptobenzothiazoles(ZMBT), diphenylguanidine (FGD).
6. The elastomeric article according to claim 1 in the form of gloves, which is at least 20% thinner than other comparable gloves made of natural rubber or nitrile rubber and designed for similar use.
7. The elastomeric article according to claim 6, and this glove has a palm region with a thickness ranging from about 0.05 to 0.12 mm
8. Elastomeric glove formed from carboxypropanoyl butadiene-nitrile rubber composition, which includes two first and second acrylic-nitrile composition comprising, taken in the proportion of 60:40 to 40:60, and has a glass transition temperature Tgin the range from -15 to -30°C, and a proportionate amount of alkali metal hydroxide and a metal oxide, where the number of alkali metal hydroxide is 0-1,5 parts per 100 dry parts of rubber, and the amount of metal oxide is greater than 0.5 but less than or equal to 1.5 parts per 100 dry parts of rubber, and the glove has a given thickness of from 0.05 to 0.12 mm in the Palmar region.
9. The elastomeric glove of claim 8, where this glove is formed from carboxypropanoyl butadiene-nitrile rubber composition having a content of Acrylonitrile in the range from 17 to 45 wt.%, and the content of the carboxylic acid of up to 15 wt.%, and the OST is Sousa part of the rubber composition is butadiene.
10. The method of manufacture of elastomeric products, providing: (a) preparation of compounded carboxypropanoyl composition of butadiene-nitrile rubber containing more than 0.5 but less than or equal to 1.5 parts of zinc oxide per 100 dry parts of rubber, alkali to bring the pH to about 8.5 or above, stabilizer, and one or more accelerators from the group comprising guanidine, dithiocarbamate and, if necessary, the connection of the thiazole; b) a dunking form in the specified compounded carboxypropanoyl composition nitrile latex rubber; and C) curing the specified compounded nitrile butadiene rubber for the formation of elastomeric products.
11. The method according to claim 10, the composition of the accelerator includes: zinc diethyldithiocarbamate (ZDEC), zinc-2-mercaptobenzothiazoles (ZMBT), diphenylguanidine (FGD).
12. The method according to claim 11, and guanidine, dithiocarbamate and thiazole are present in a ratio of about 2:1:1 respectively.
FIELD: rubber industry.
SUBSTANCE: invention relates to technology of manufacturing rubber reinforcement cord. Cord coating composition comprises first rubber latex, phenol resin, and water-soluble resorcinol-formaldehyde condensation product. Weight percentages of first rubber, phenol resin, and condensation product based on solid components of composition lie in ranges: 30 to 95, 0.01 to 30, and 2 to 15, respectively. First rubber is a nitrile group-containing high-saturated polymer rubber characterized by iodine number 120 or lower. Water-soluble condensation product belongs to novolak type.
EFFECT: increased bend resistance and size stability at room temperature and high temperatures.
10 cl, 1 dwg, 6 tbl, 5 ex
FIELD: polymer materials.
SUBSTANCE: invention relates to a method for preparing friction material, which can be used for making friction unit parts for a variety of mechanisms and machines such as brake members of drum and disk brakes, motor car couplings, etc. Material contains, wt %: powderlike polyamine-imine resin (PAIS-104) 10-15, butadiene-nitrile rubber latex 2-5 (for solids), fibrous filler 15-25, carbon filler 2-7, alumina 10-15, bronze chippings 3-5, graphite 0.5-2.0, calcium hydroxide 0.5-1.0, and barite concentrate - the balance. Fibrous filler is a mixture of polyoxadiazole fiber (Oksalon), basalt fibers, and glass fibers at their ratio (1-2):(3-5):(1-2). Carbon filler is a product obtained by heat treatment of non-stoichiometric titanium carbide TiCx (0.5≤x≤1) impregnated with industrial machine oil, diesel fuel, exhausted oil, or mixture thereof, said heat treatment being carried out at 700-900°C under an inert atmosphere.
EFFECT: enhanced corrosion resistance of material and suppressed release of phenol during manufacture and use of material.
3 tbl, 3 ex
SUBSTANCE: invention relates to processing polyvinyl chloride through dispersion, particularly to production of highly filled adhesive plastisols used in making protective coatings in motor-car construction, as anticorrosion protection of inner surfaces of metal structures. The method of producing highly filled plastisol based on polyvinyl chloride involves successive addition and mixture in a mixer of di(2-ethylhexyl)phthalate, triethylene glycol dimethacrylate, isopropylbenzene hydroperoxide, half of the given amount of kaolin, calcium strearate, polyvinyl chloride and the remaining amount of kaolin. Aliphatic silicon acrylate, diatomite and NGZ-4 phosphate hydraulic fluid are added before adding polyvinyl chloride, and after adding the remaining amount of kaolin, a polysulphide oligomer - liquid thiocol II with weight ratio of SH groups of 1.7-2.6% and molecular weight of 2100 is added.
EFFECT: high degree of restoration of the thixotropic structure, extrusion, fire resistance and tensile strength of the polyvinyl chloride plastisol and the hardened material.
SUBSTANCE: invention relates to processing polyvinyl chloride through dispersion, particularly to production of highly filled adhesive plastisols used in making protective coatings in motor-car construction, as anticorrosion protection of inner surfaces of metal structures. The method of producing highly filled plastisol based on polyvinyl chloride involves successive addition and mixture in a mixer of di(2-ethylhexyl)phthalate, triethylene glycol dimethacrylate, isopropylbenzene hydroperoxide, half of the given amount of kaolin, calcium strearate, polyvinyl chloride and the remaining amount of kaolin. Hexafunctional oligourethane acrylate, diatomite and NGZ-4 phosphate hydraulic fluid are added before adding polyvinyl chloride, and after adding the remaining amount of kaolin, a polysulphide oligomer - liquid thiocol II with weight ratio of SH groups of 1.7-2.6% and molecular weight of 2100 is added.
EFFECT: high degree of restoration of the thixotropic structure, extrusion, fire resistance and tensile strength of the polyvinyl chloride plastisol and the hardened material.
SUBSTANCE: method of producing compound synthetic polyisoprene latex which is suitable for making latex films involves (a) compounding synthetic polyisoprene latex with suitable compounding ingredients, (b) maturating the latex and optionally (c) storing the latex. Steps (a), (b) and (c), if included, are carried out at temperature lower than 20°C in order to minimise latex precuring.
EFFECT: article with improved physical properties.
28 cl, 3 tbl, 3 ex
SUBSTANCE: invention relate to moulded elastomer articles obtained from a vulcanised composition of synthetic elastomer latex with an accelerator composition. The accelerator composition for synthetic rubber latex obtained from conjugated diene and optionally vinyl aromatic comonomer contains: (i) diisopropyl xanthogen polysulphide 0.25-1.0, (ii) alkyldithiocarbamate 0.25-1.0, where the alkyl chain contains 5-20 carbon atoms, and (iii) diphenyl guanidine 0.25-1.0 per 100 parts of dry synthetic rubber. The vulcanised aqueous composition of synthetic rubber latex contains the said accelerator composition.
EFFECT: higher stability of the latex composition, higher technological effectiveness of the method due to reduction of toxicity of the components used.
7 cl,1 tbl, 1 ex
SUBSTANCE: invention relates to compositions for making elastomer films used in making synthetic gloves, and a method of making elastomer films and gloves. The composition contains a synthetic polymer, sulphur, a metal oxide cross-linking agent and water. Sulphur is in amount of 0.01-0.5 parts per 100 parts of the polymer (phr). Total concentration of solid substances in the composition is 5-20% of the mass of the composition and the said composition does not contain an accelerator. The method of making a multilayer elastomer film involves the following steps: (i) dipping a mould into the composition, (ii) drying the composition and (iii) dipping the mould into the composition in order to deposit an additional layer of the elastomer film composition onto the mould, (iv) optional repetition of steps (ii) and (iii) and (v) drying and curing the elastomer film. The average thickness of the layer is 6-90% of the average overall thickness of the multilayer film. The average overall thickness of the elastomer film is approximately 0.01-0.3 mm.
EFFECT: increased strength of the multilayer elastomer film, reduced amount of composition for making an ariticle and reduced allergic reactions during contact with the elastomer films.
24 cl, 10 tbl, 2 ex
FIELD: articles of personal use.
SUBSTANCE: rubber glove with hand protective covering relates to surgical gloves and can be applied in medicine. Glove contains part of cuff and internal part. Glove contains dry covering from emulsified hand protective mixture. Mixture contains at least one water-soluble hygroscopic substance - humidifier, at least one water-soluble lubricant, at least one water-soluble SAS and at least one water non-soluble occlusive humidifier, which is evenly and completely dispersed in mixture. Mixture, which is applied on skin in process of glove putting on, is activated by moisture, produced by skin. Said glove is obtained by following method. Preliminarily heated form is submerged in water coagulant. After that form is submerged in water dispersion of rubber for formation of gel-like rubber layer and in water dispersive system for formation of smooth polymer covering. Rotation in dryer of glove with hand protective mixture of said composition with following drying.
EFFECT: increase of hand protection degree and simplification of glove putting on dry or wet hands and one glove on another.
31 cl, 19 tbl, 17 ex
FIELD: process engineering.
SUBSTANCE: proposed invention relates to surface processing of certain areas in composite material structure. Processing is conducted by, at least, one plasma beam at atmospheric pressure, said beam being produced by plasma generator furnished with emission nozzle to facilitate adhesion binding with the other structure. Plasma beam sent through the nozzle comprises active gas projected onto composite material structure from the distance varying from 0.2 to 10 cm and at incidence angle varying from 75° to 105°. Note here that plasma beam is directed so that the angle of contact with composite material structure makes less than 90°. Note here that composite material structure wets the surface of another structure. Note also that the angle of contact represents an indicator of efficiency of structures adhesion binding.
EFFECT: higher reproducibility and reliability, lower costs.
11 cl, 6 dwg
SUBSTANCE: antiallergic natural or artificial latex or polyvinylchloride product, for gloves or condom producing, containing in matrix of natural or artificial latex or polyvinylchloride one or more natural antiallergic medicine, selected from baikalin, matrin, liquorice saponin, tea polyphenol, arctigenin, aleanolic acid, tetrandrin, sodium ferulat, general alkaloid of Asian moonseed root, extract of dittany root bark, ginkgo biloba A, general glycoside of anemone flaccida Fr. Schmidt root, extract of engelhardtia chrysolepis, magnoline, osthol and catechine, that are produced by mixing natural antiallergic medicine and natural or artificial latex or polyvinylchloride, charging of obtained admixture into the mould, extraction from the mould, treatment at high temperature with subsequent rinsing and drying.
EFFECT: invention solves a problem of idiosyncrasy to the condom or glove in their previous design by adding natural antiallergic medicine into the latex or polyvinylchloride product.
8 cl, 8 ex
FIELD: personal use items.
SUBSTANCE: invention relates to medical gloves and other latex items, in the production of which is used a powderless coagulant, and to a sequenced-flow mode method of making powderless latex gloves from synthetic and natural rubber and other items from latex. The powderless elastomer item contains elastomer material, chosen from natural and synthetic latex, and has a first and second surface. The first surface forms the outer surface of the item, covered by a layer of powderless coagulant. The powderless coagulant composition contains one or more calcium salts, fine polyethylene with high density, amino silicon microemulsion, dimeticone emulsion, non-ionic surfactant based on acetylene diol and water. The second surface of the elastomer material forms the inner surface of the item, covered by a layer of polyurethane or acrylic polymer for making wearing easier. The elastomer item, particularly medical gloves, is produced using a process for making latex items in sequenced-flow mode, which involves immersion of hand-shaped moulds into the coagulant before immersing them in latex. The gloves are covered with a polymer for making wearing easier before removing the gloves from moulds.
EFFECT: easier removal of items from moulds, easier double wearing of gloves and exclusion of the need for using an automatic process.
1 tbl, 9 ex
SUBSTANCE: invention concerns elastomer item with polymer fiber coating including elastomer or elastomer mix, fiber or fiber mix, surfactant and dine wax lubricant. Thin or foamed coating layer can be applied to domestic or industrial gloves. Elastomer item is produced by mould dipping in salt-based coagulant with further dipping in elastomer dispersion and then in medium for composite polymer fiber coating forming. Elastomer item includes first layer with natural or synthetic polymer, second layer including foamed natural or synthetic polymer, and third layer linked to second layer and including composite polymer fiber coating. Coating can be foamed.
EFFECT: improved antiperspiration properties and exfoliation resistance.
11 cl, 4 dwg, 17 ex
SUBSTANCE: polychloroprene article contains polymer easily (in comparison with polychloroprene) chlorinated. The method of fabrication includes the article forming from water dispersion or polychloroprene solution. The method comprises including to dispersion or to polychloroprene solution one or more polymers easily (in comparison with polychloroprene) chlorinated. Preferentially the article represents the glove made of polychloroprene and containing carboxylated butadiene-acrylonitrile rubber, carboxylated styrene-butadiene rubber or polyisoprene.
EFFECT: decreasing of surface layer facilitates putting on gloves one pair to another.
13 cl, 5 ex
SUBSTANCE: scope of invention covers stabilized water dispersions of curing agent suitable for coating preparation. Dispersion dispersed in water contains the following components: A1) at least one organic polyisocyanate with isocyanate groups connected in aliphatic, cycloaliphatic, araliphatic and/or aromatic manner, A2) ionic or potentially ionic and/or non-ionic substance, A3) blocking agent, B) stabilizer containing a) at least one amine with structural element of common formula (I) without any hydrazide group, b) substance with formula (IV) .
EFFECT: resistance to thermal yellowing increases.
6 cl, 5 tbl, 11 ex
FIELD: personal use articles.
SUBSTANCE: glove includes a knitted lining, having multiple stitches, made of a thread with a number of 221 denier or less, and the polymer latex coating glued to the knitted lining. The polymer latex coating penetrates by a half or more into the thickness of the knitted lining, but does not penetrate for the whole thickness of the knitted lining, at least on a part of the knitted lining. The polymer latex coating has a thickness in the range of 0.75-1.25 of the knitted lining thickness. The surface of the knitted lining in contact with skin is substantially free of the polymer latex coating. There is a method provided to manufacture a glove.
EFFECT: invention ensures more convenience of use.
15 cl, 5 dwg
FIELD: personal use articles.
SUBSTANCE: protective glove is made at least partially of multi-layer material. Multi-layer material includes multiple elastic strands arranged between the first and second non-woven fabrics. Elastic strands are fixed to specified non-woven fabrics in extended condition so that in weakened condition of specified elastic strands the first and second non-woven fabrics are assembled and form creases. Specified multi-layer material is extensible and steam permeable and maintains desired shape of glove, at least partially by means of seams formed by ultrasonic connection. At the same time seams are less than 2 mm in height and function as fixtures for elastic strands. Invention relates also to method for manufacturing of protective glove.
EFFECT: improved design of glove is soft, breathing and flexible, at the same time discomfort of any seam is eliminated in wearing of glove, and easy putting on and removal of glove from user's hand is provided.
14 cl, 10 dwg
FIELD: personal use articles.
SUBSTANCE: invention relates to a leather-haberdashery industry and can be used for manufacturing of gloves from natural and artificial leather. Method of measurement of a hand for making gloves includes location of the right hand to the set measuring position with the fixation of the hand position using the fixing element located on the level of the second web space, measurement of length of the third finger using a measuring scale and a hand circumference with a measuring tape, and a subsequent averaging of the obtained values of the third finger length and a hand circumference. Right hand is set on the measuring position with the palm side up and the flexor length of the third finger, the length of decorative edge of nail, the actual value of a hand circumference at the level of the fifth metacarpophalangeal joint are consistently measured, as well as a hand length from the fixing element which is located in the second web space to the middle of the hand baseline with a preliminary determination of the hand baseline by bending the latter in wrist until it stops. Then the rotation angle of the first metacarpal is determined relative to the longitudinal hand axis with radiography. Based on the obtained dimensional characteristics of the hand taking into account the proportionality coefficient of the width and length a model of a glove is made.
EFFECT: improvement of the glove nicety and its contact with the hand due to measurement the additional dimensional characteristics on the palm of the hand and the definition of angle of rotation of the first metacarpal bone relative to the longitudinal axis of the hand with radiography.