Aqeuous polytetrafluoroethylene emulsion, fine polytetrafluoroethylene powder and porous material produced therefrom

FIELD: chemistry.

SUBSTANCE: invention relates to a novel aqueous polytetrafluoroethylene emulsion obtained using a special fluorinated emulsifying agent, and to fine polytetrafluoroethylene powder and porous material produced from said powder. Described is a porous material produced from polytetrafluoroethylene via extrusion of a paste of fine polytetrafluoroethylene powder which is obtained through coagulation of aqueous polytetrafluoroethylene emulsion obtained during emulsion polymeristion of tetrafluoroethylene in an aqueous medium using a fluorinated emulsifying agent of formula (I): CF3CF2OCF2CF2OCF2COOA, in which A is an alkali metal atom or an NH4 group taken in amount of 1500-20000 parts per million relative the final output of polytetrafluoroethylene, followed by stretching.

EFFECT: obtaining porous material with excellent various characteristics, made from polytetrafluoroethylene, having excellent processability during extrusion of the paste.

5 cl, 3 ex, 1 tbl, 1 dwg

 

The technical field to which the invention relates

The present invention relates to new aqueous PTFE emulsion obtained with the use of special fluorinated emulsifier, and to the PTFE fine powder and porous material derived from it.

Background of invention

When fluorinated polymer such as polytetrafluoroethylene (hereinafter referred to as PTFE), is obtained using the emulsion polymerization method, commonly used fluorinated emulsifier, as it does not inhibit the reaction of polymerization of fluorinated monomer to chain transfer in the aquatic environment.

The aqueous PTFE emulsion obtained by the emulsion polymerization of tetrafluoroethylene (hereinafter referred to as TPV). When koagulirovannogo water emulsion followed by drying receive the fine powder of PTFE. The fine powder is formed by extrusion of a paste and is then used for various purposes. On the other hand, aqueous dispersion of PTFE obtained by concentration or processing to make the stability of the aqueous emulsion, as required, is used for various applications, such as applying for coverage or apply for impregnation with the introduction of various additives.

For emulsion polymerization Porirua the aqueous monomer as fluorinated emulsifier is usually used moniperformance (structural formula: CF 3(CF2)6COONH4(hereinafter referred to as APFO (APFO)). In recent years, from the point of view of ecology, it has been proposed to regulate the release of APFO because APFO not present in nature and hardly decomposed. In addition, it was noted that APFO has a high capacity for bioaccumulation.

However, in the emulsion polymerization of the TPV, it is difficult to reduce the amount of fluorinated emulsifier. In addition, to remove the fluorinated emulsifier of an aqueous PTFE emulsion, aqueous dispersion of PTFE or wastewater after coagulation of emulsion polymerization, it is necessary new equipment, and the cost of obtaining PTFE will increase.

It was therefore proposed fluorinated emulsifier other than APFO, which is used for copolymerization of fluorinated monomer alone or fluorinated monomer and another monomer (patent documents 1, 2, 3 and 4).

Patent document 1 discusses examples that use fluorinated emulsifier of the formula

F-(CF2)p-O-(CF(Y)-CF2-O-)q-CF(Y)COOB,

in which Y represents a fluorine atom or performatrin group, p is 1 to 5, q is 0 to 10, and represents a hydrogen atom or a monovalent salt. Examples include a case in which tonirovany emulsifier structural formula CF 3CF2OCF2CF2OCF2COONH4used for copolymerization TPV and hexaferrite (hereinafter referred to as HFP (HFP)). In this case, it is estimated that the amount of fluorinated emulsifier is 1040 hours/million in relation to the number of the finally formed copolymer.

However, patent document 1 does not consider the case of polymerization TPV separately when using fluorinated emulsifier. In addition, when TPV polymerized separately when using fluorinated emulsifier in the amount of 1040 hours/million in relation to the number of permanently formed of PTFE (hereinafter also referred to as the final output PTFE), the rate of polymerization shows an abnormal value, and produce large quantities of the hardened product, therefore, it was found that it is difficult to carry out emulsion polymerization stable.

In addition, the standard relative density of TFE and HFP, which was obtained in example of patent document 1, is 2,200. This is the standard relative density shows that the molecular weight of the copolymer is low. Namely, it shows that there is such a problem that even if TPV and HFP copolymerizate when using fluorinated emulsifier, can be obtained only copolym the R TPV/HFP, having low molecular weight.

In addition, the TFE and HFP in water emulsion, which is obtained in example of patent document 1 has an initial average particle size 0,176 μm, i.e. the particle size is small. Generally, in the case where the paste extrusion is carried out using the fine powder obtained from particles having a small initial average particle size, there is the problem of insufficient processability in the extrusion, the extrusion pressure of the paste increases and appearance of the molded product deteriorates. In addition, in the case where, in applying for coverage used aqueous dispersion of PTFE obtained by introduction of various additives in the aqueous PTFE dispersion, there is a problem that, if the initial average particle size is small, the applied film is likely cracks.

In addition, generally it is known that in emulsion polymerization TPV, if the number of fluorinated emulsion increases, the initial average particle size of the obtained PTFE becomes small. In the case of the example of the patent document 1, it is expected that, if the amount of fluorinated emulsifier is increased, the initial average particle size will be less.

In the example of patent document 2 as a polymerization emulsifier uses the I CF 3CF2CF2C(CF3CF2OCF(CF3)COONH4and found that the emulsifier has a higher capacity for bioaccumulation than APFO.

In the example of patent document 3 as a polymerization emulsifier is considered CF3CF2CF2C(CF3)2CF2(CH2)2COONH4and so, fluorinated emulsifier, if the hydrogen atoms are introduced into the molecule of the fluorinated emulsifier in the polymerization of fluorinated monomer, probably, chain transfer, so there is a problem that the molecular weight of the obtained fluorinated polymer is not high enough.

In the examples of patent document 4 as for emulsion polymerization are considered F(CF2)5OCF(CF3)COONH4etc.

Patent document 1: JP-B-39-24263.

Patent document 2: JP-A-2003-119204.

Patent document 3: JP-A-2002-308914.

Patent document 4: JP-A-2002-317003.

The objectives of the invention achieved by the invention

The aim of the present invention is to provide a water emulsion of PTFE, which essentially does not contain APFO capable of PTFE having a high molecular weight, which can increase initial average particle size to a relatively large level from 0.18 to 0.50 μm, and receive, the emulsion polymerization. In addition, another objective of the present invention is to obtain fine powder of PTFE, which is obtained from a water emulsion of PTFE and which has excellent processability, extrusion of the paste, and, in addition, the creation of a porous material derived from fine powder PTFE.

Means of achieving goals

The authors of the present invention found that, in emulsion polymerization TPV when using fluorinated emulsifier of the formula (1) in an amount of from 1500 to 20000 h/m relative to the final output PTFE polymerization can be carried out smoothly, even if TPV polymerized separately or lightly copolymerized with a small amount of fluorinated co monomer. In addition, they found that it is possible to increase the initial average particle size of the obtained PTFE to a relatively large level from 0.18 to 0.50 μm; it is possible to obtain high molecular weight PTFE having a standard specific gravity from up to 2,20 2,14; and fine PTFE powder obtained from the aqueous PTFE emulsion is excellent in paste extrusion. The present invention is made on the basis of these discoveries.

Namely, the present invention provides the following:

1. The aqueous PTFE emulsion obtained by carrying out emulsion polymerization TPV separately Il is together with other copolymerizing monomer in an aqueous medium, where the fluorinated emulsifier of the formula (1):

Called XCF2CF2(O)mCF2CF2OCF2COOA,

in which X represents a hydrogen atom or a fluorine atom, And represents a hydrogen atom, alkali metal or NH4and m represents an integer of 0 or 1,

is used in an amount of from 1500 to 20000 h/m relative to the final output of PTFE.

2. The aqueous PTFE emulsion according to claim 1, in which the initial average particle size of PTFE in the aqueous PTFE emulsion is from 0.18 to 0.50 microns.

3. The aqueous PTFE emulsion according to claim 1 or 2, in which the amount of fluorinated emulsifier of the formula (1) is from 2000 to 20000 h/m relative to the final output of PTFE.

4. The aqueous PTFE emulsion according to any one of claims 1 to 3, in which the fluorinated emulsifier of the formula (1) is the connection

CF3CF2OCF2CF2OCF2COONH4.

5. Fine PTFE powder obtained by coagulation of aqueous PTFE emulsion according to any one of claims 1 to 4.

6. The fine powder of PTFE according to claim 5, which has a standard relative density of up to 2,20 2,14.

7. The porous material of PTFE obtained by extrusion of a paste of fine PTFE powder according to claim 5 or 6, followed by stretching.

The effects of the invention

Aqueous emulsion of PTFE according to the present invention has no problem with the environment,which can be made performancenow acid or its salt. In addition, an aqueous emulsion of the present invention is able to provide PTFE having a high molecular weight, and it can increase initial average size of the particles to a relatively large level from 0.18 to 0.50 μm. In addition, the fine powder of PTFE according to the present invention is excellent in various characteristics such as processability, extrusion of paste. The porous material of PTFE according to the present invention is excellent in various characteristics.

The best option of carrying out the invention

In the present invention the emulsion polymerization is carried out using TPV alone or TPV together with other copolymerizing monomer (hereinafter referred to as the co monomer).

The co monomer can be, for example, HFP, simple Perfora(alkylvinyl ether) ((PTAVE)(PFAVE), chlorotrifluoroethylene ((HTFA)(CTFE)), (performance)ethylene, vinylidenefluoride ((WDF) (VdF)), simple Perfora(alkenylphenol ether), WDF (VDF), Perfora-(2,2-dimethyl-1,3-dioxol) or Perfora-(4-alkyl-1,3-dioxol). Such comonomers may be used separately or in combination as a mixture of two or more of them.

In the present invention PTFE obtained by the emulsion polymerization include both homopolymer TPV and modified PTFE. As a homopolymer TPV and modifier the bath PTFE are polymers, processed not from the melt.

The modified PTFE is a polymer having a TPV, copolymerizable with co monomer in such an extent that the processability of the melt, they do not possess. The content of the component parts on the basis of the co monomer in the modified PTFE is, preferably, at most 0.5 wt.%, more preferably, at most 0.4 wt.%, relative to all constituent units.

The number of co monomer introduced in the beginning of polymerization upon receipt of the modified PTFE varies depending on the type of co monomer. However, the larger the amount of the co monomer, the higher is the stability of the resulting aqueous emulsion, so that the initial average particle size will decrease. In the present invention, the number of co monomer introduced in the beginning, is set such as to bring the original average particle size up to a level of from 0.18 to 0.50 microns.

The number of co monomer introduced in the beginning, is preferably from 0 to 0.5 wt.%, more preferably from 0 to 0.4 wt.%, with respect to the target output of PTFE.

Suitable for use is a fluorinated emulsifier of the formula (1), as it provides a good function to stabilize the polymerization of PTFE. In the formula (1) X preferably represents a fluorine atom from the viewpoint of the stable is a major. In addition, the value of m is preferably 1 from the viewpoint of polymerization stability and mechanical stability of aqueous emulsion of PTFE.

And may constitute, for example, H, Li, Na, K or NH4. NH4it is especially preferred because it has good solubility in water, and the metal ion remains in the fine PTFE powder as an impurity.

Among the fluorinated emulsifier of the formula (1) is particularly preferred is, for example, CF3CF2CF2CF2OCF2COONH4or CF3CF2OCF2CF2OCF2COONH4(hereinafter referred EEA), and the EEA is more preferred.

Fluorinated emulsifier of the formula (1) are obtained in a known manner fluoridation, such as liquid-phase method of fluorination, which use the corresponding non-fluorinated emulsifier or an ester of partially fluorinated compounds, and it interacts with fluorine in a liquid phase, and in the method of fluorination using cobalt fluoride or use the method of electrochemical fluorination, and the resulting fluorinated ester bond is hydrolyzed, followed by purification and then neutralizing with ammonia.

When is emulsion polymerization TPV, fluorinated emulsifier of the formula (1) is used in the share of the ve from 1500 to 20000 h/m relative to the final output of PTFE, and preferably from 2000 to 20000 h/m relative to the final output of PTFE. If the amount of the fluorinated emulsifier of the formula (1) is too large, the shape of the initial particles tends to be rod-and water emulsion is unstable.

In the emulsion polymerization of the present invention in the polymerization process TPV or TPV together with another co monomer used water, fluorinated emulsifier of the formula (1), a stabilizer, a polymerization initiator, etc. in Addition, as conditions of polymerization, the polymerization temperature is preferably from 10 to 95°C, pressure of polymerization is preferably from 0.5 to 4.0 MPa, and the polymerization time is from 90 to 520 minutes

The stabilizer may be, for example, paraffin wax, fluorine oil, fluorine-containing solvent or silicone oil. Such stabilizers can be used individually or in combination as a mixture of two or more of them. As a stabilizer is preferred paraffin wax. Paraffin wax can be liquid, semi-solid or solid at room temperature, and preferred is a saturated hydrocarbon having at least 12 carbon atoms. The melting point of paraffin wax is usually preferably from 40 up to 65°C, more preferably from 50 to 65°C. the Amount of the stabilizer is preferably from 0.1 to 12 wt.%, more preferably from 0.1 to 8 wt.% in relation to the weight of water used.

As a polymerization initiator in a suitable case is used, for example, water-soluble radical initiator or a water-soluble catalyst oxidation-reduction. As a water-soluble radical initiator is preferred persulfate such as ammonium persulfate or potassium persulfate, or a water-soluble organic peroxide, such as hydrogen peroxide dinternal acid, peroxide, bis-glutaric acid or tert-butylhydroperoxide. These polymerization initiators may be used individually or in combination as a mixture of two or more of them. In addition, in the same way can also be used with oil-soluble initiator. As an initiator of polymerization is preferred peroxide dinternal acid.

The amount used of the polymerization initiator is usually preferably from 0.01 to 0.20 wt.%, more preferably from 0.01 to 0.15 wt.%, with respect to the target output of PTFE.

In the emulsion polymerization of the present invention can be used control degree of polymerization, such as an alcohol, e.g. methanol or canal, in order to regulate the molecular weight of PTFE and increase the stability of the aqueous emulsion. As the regulator of the degree of polymerization is more preferred is methanol.

The number of control degree of polymerization is usually preferably from 0 to 1·10-4wt.% and more preferably from 0 to 5·10-5wt.% with respect to the target output of PTFE.

According to the present invention the initial average particle size of the original particles of PTFE in the aqueous PTFE emulsion obtained by the emulsion polymerization may be in the range from 0.18 to 0.50 μm, in particular in the range from 0.19 to 0.40 μm. In the present invention the initial average particle size is an average size, measured by the analyzer of the distribution of particle size by laser scattering.

The concentration of PTFE in the aqueous PTFE emulsion obtained by the emulsion polymerization is preferably from 10 to 45 wt.%. If the PTFE concentration is too low, it will be difficult to coagulate the original particles of PTFE aqueous emulsion. If the PTFE concentration is too high, will remain decoagulant source of PTFE particles, and the liquid after coagulation will be muddy. The PTFE concentration is more preferably from 15 to 45 wt.%, even more preferably from 20 to me.%.

As a method of obtaining a fine powder of PTFE aqueous emulsion of PTFE can be used a known method. For example, there may be mentioned a method in which the aqueous PTFE emulsion is diluted with water to a concentration of from 8 to 20 wt.% followed by intensive stirring to coagulate the source of the PTFE particles. Can be adjusted pH, or may be a flocculating agent, such as an electrolyte or a water-soluble organic solvent. Then with proper mixing the fine powder PTFE coagulated with its original particles, is separated from water, followed by granulation, the regulation of the particle size and drying to obtain fine powder of PTFE.

Fluorinated emulsifier of the formula (1)contained in water after coagulation of the PTFE is separated, extracted using the method of adsorption is carried him ion exchange resins, or the concentration, for example by evaporation of water.

The dried fine powder PTFE is usually held in the state, calling small for wet powder obtained usually by coagulation, preferably in the state, leaving him motionless, with the help of vacuum, high frequency waves, hot air or the like. Drying is carried out at a temperature of preferably from 10 to 250°C, particularly p is edocfile - from 100 to 230°C.

Fluorinated emulsifier of the formula (1), adsorbed on the fine PTFE powder, is removed by the introduction of air coming in the drying process, the alkaline aqueous liquid.

According to the present invention can increase the relative density of the fine powder of PTFE to range from up to 2,20 2,14, and can be obtained PTFE having a high molecular weight. In addition, by changing the conditions of emulsion polymerization can be increased relative density before the interval, the more 2.20 to 2.25.

In addition, the average particle size of the fine PTFE powder of the present invention is preferably from 350 to 650 μm, more preferably from 400 to 600 μm. In addition, the bulk density is preferably from 0.35 to 0.65 g/ml, more preferably from 0.40 to 0.60 g/ml

When the average particle size is within the specified interval, the fine powder PTFE has excellent processability, extrusion of the paste, and the molded product has excellent surface smoothness.

Fine powder PTFE can be used for paste extrusion. Extrusion of the paste is carried out so that the fine powder of PTFE mixed with a lubricant, which allows fine powder PTFE having fluidity at molding product such as plank is or pipe. The degree of mixing of sizing can be installed properly to allow fine powder PTFE to have fluidity, and it is usually from 10 to 30 wt.%, particularly preferably 15 to 20 wt.%. As lubricant is preferable to use naphtha or petroleum hydrocarbon having a point end boiling point of at least 100°C.

In addition, you can enter an additive such as a pigment for coloring or various fillers to impart strength and electrical conductivity.

PTFE of the present invention has a stress relaxation preferably at least 500, more preferably at least 530 C, particularly preferably at least 550 C.

The product form of paste extrusion fine powder PTFE may be different, such as tubular, sheet-like, blankaartia or fiber-like. Its applications can be, for example, pipe, wire coating, sealing materials, porous membranes or filters.

Product paste extrusion of fine PTFE powder then is stretched to obtain a porous PTFE material. As a condition of stretching used appropriate speed, for example 5-1000%/s, and the proper degree of tension, such as at least 500%.

The porosity of the porous Mat is the Rial is not specifically limited, but the porosity is usually preferably in the range from 50 to 99%, particularly preferably from 70 to 98%. The product, consisting of a porous material may be of various shapes, such as tubular, sheet-like, plenkoobrazovatel or fiber-like.

Examples

Now the present invention will be described in detail through examples and comparative examples, but it should be clear that the present invention is not limited to them. Methods of determining the characteristics of the fine PTFE powder are as follows:

(A)The original average particle size (unit: μm)PTFE obtained by the emulsion polymerization by using distribution analyzer particle size by laser scattering (trade mark: “LA-920”, manufacturer : HORIBA, Ltd.).

(C)Standard relative density(hereinafter referenced as the "SOP" ("SSG")): determined in accordance with ASTM D1457-91a and D4895-91a. Weighed 12.0 g of PTFE and is kept in a cylindrical mold with an inner diameter of 28.6 mm under a pressure of 34.5 MPa for 2 minutes the mold is placed in an oven at 290°C, and increase the temperature at a rate of 120°C/h It is maintained at 380°C for 30 min, then lower the temperature at 60°C/h, and maintain the mold at 294°C for 24 minutes Molded product is kept in execut the d at 23°C for 12 hours Then determine the relative density of the molded product in water at 23°C and accept as a standard relative density.

(C) Average particle size (Edinet: μm) of fine powder PTFE:determined in accordance with JIS K6891. Standard sieves of 20, 30, 40 and 60 mesh installed in the package in the order listed from top to bottom. The powder is poured on 20 mesh and sift, determine the mass of the PTFE powder remaining on each sieve. The amount of 50% of the particles, calculated on a logarithmic probability based on the above mass is taken as the average particle size.

(D) Apparent density (unit: g/ml):determined in accordance with JIS K6891. In the weighted bottle stainless steel with an internal volume of 100 ml download the sample from the hopper installed above, and the portion of the sample, protruding from the weighted bottles, scraped flat plate. Then determine the mass of the sample remaining in the suspended bottles, and a value obtained by dividing the sample mass on the internal volume weighted bottles, take as apparent density.

(E) Evaluation of pressure extrusion and compliance

100 g of fine powder of PTFE, which was maintained at room temperature for 2 h, loaded into a glass bottle having an inner capacity of 900 cm3and add to 21.7 g of sizing Isopar H (zaregistrirovannaya trade mark; manufacturer - Exxon Corporation), followed by mixing for 3 min with a production of PTFE-mixture. The obtained PTFE-mixture was kept at a constant room temperature for 2 h, ekstragiruyut through the die plate, having a diameter of 2.5 cm, a length of 1.1 cm and the angle of insertion 30°, at 25°C in terms of the degree of extraction (the ratio of the cross-section at the entrance to the cross section at the exit of the nozzle) 100 and the extruding speed of 51 cm/min with the receiving roller extrusion of paste. Determine the pressure required for extrusion at this time, and refer to it as the extrusion pressure. Received the platen dried at 230°C for 30 min to remove sizing. Then cushion cut into appropriate pieces, each end of the clamp so that the length between the clamps is 3.8 cm and 5.1 cm, and heated at 300°C in an oven with air circulation. Then stretch a given speed as long as the length between the clamps will not be equal to a given length.

This method of stretching is a essentially the method discussed in U.S. patent 4576869, except different speed extrusion (51 cm/min). "Stretching" is the increase in length, and it usually represents the ratio to the original length.

(F) Determination of tensile strength

The sample for determination of bursting strength is obtained by stretching roller the same about the time, as when determining compliance, in terms of the length between the clamps of 5.1 cm, speed, stretching 100%/s and the total stretching 2400%. Tensile strength is defined as the minimum load tensile strength among the three samples obtained from the stretchable cushion, i.e. one sample from each end of the stretchable cushion (if between the clamps was the formation of a neck, it missed) and one sample from its center. The sample is firmly clamped movable clamp with the clearance of 5.0 cm, and the movable clamp is given with a speed of 300 mm/min, and determine the tensile strength at room temperature using TENSILON (A&D Co., LTD.).

G.Determination of the relaxation time voltage

The sample to determine the relaxation time of the voltage produced by stretching roller in the same manner as when determining compliance, in terms of the length between the clamps of 3.8 cm, speed, stretching 1000%/s and the total stretching 2400%. Each end of this sample of the stretchable cushion attached to the mounting bracket, and the sample is stretched to a total length of 25 cm, the relaxation Time of the voltage represents the time required for the destruction of this sample when it is aged in an oven at 390°C. This temperature corresponds to the temperature is higher than 380°C, which is the rate is Atyrau, considered in the description of U.S. patent 5470655 and in which a stretched chain form melts. The sample, mounted fixture that is installed into the furnace through the gap (closed)made in the side, so in the process of introducing the sample temperature is not reduced. So there is no need to spend time on the recovery temperature, as discussed in the description of U.S. patent 4576869.

Reference example 1

Get sample CF3CF2OCF(CF3CF2OCF(CF3)COONH4

2.58 g CsF and 13,06 g tetragona loaded into the autoclave from an alloy Hastelloy having a capacity of 200 ml, followed by degassing, and then injected 20,83 g CF3COF. Then the autoclave is cooled to a temperature of -20°C and in air-tight conditions and with stirring enter 57,5 g geksaftorpropilenom during the period of time of about 1 h, the Initial pressure is 0.6 MPa. The reaction is continued for about 1 h before until the pressure no longer decreases, and then the autoclave to return to room temperature to obtain 78,57 g of the crude reaction liquid. The liquid to be analyzed by GC method, which found that in addition to the target product 49,7% CF3CF2OCF(CF3CF2OCF(CF3)COF contains 19.1% of CF3CF2OCF(CF3)COF and 12.8% CF3CF2O(CF(CF 3CF2O)2CF(CF3)COF.

The same reaction carried out using a 32,26 g CF3COF. Distillation and purification is carried out at the join between 2 parties, the reaction crude liquid containing the obtained target product. When using 30 cm distillation column provided with reflux condenser and filled with stuffing Helipack No. 1, receive 52,47 g of the desired product having a boiling point of 71°C/400 Torr. The target product is loaded into the reactor, made of PTFE, and added dropwise 2,32 g of water with stirring to conduct hydrolysis. Then, when the bubbling of the nitrogen is removed with HF receiving 50,45 g of the crude liquid CF3CF2OCF(CF3CF2OCF(CF3)COOH. The crude liquid is subjected to simple distillation using an apparatus of simple distillation, made of glass, to obtain 40 g of CF3CF2OCF(CF3CF2OCF(CF3)COOH.

Then, using 40 g of CF3CF2OCF(CF3CF2OCF(CF3)COOH exercise its conversion into ammonium salt. Namely, when using a reactor made of glass, 40 g of the above carboxylic acid are dissolved in 150 g CClF2CF2CHClF and then 10,89 g of 28% ammonia water is added dropwise at room temperature with the formation of the ammonium salt. After that, the solvent is distilled off CClF2CF2CHClF followed with scoi under reduced pressure to get 39,4 g CF 3CF2OCF(CF3CF2OCF(CF3)COONH4in the form of a white solid.

Reference example 2

Determination of distribution coefficient of 1-octanol/water

(lg POW)

In accordance with the OECD standard test 117 allocation ratio of 1-octanol/water (lg POW) fluorinated emulsifier determined using HPLC (HPLC) (HPLC).

Terms definitions are as follows: column: column TOSOH ODS-120T (diameter of 4.6 MC mm), solvent for elution: acetonitrile/0.6% an aqueous solution of HClO4=1:1 (vol.%/vol.%), flow rate: 1.0 ml/min, sample quantity: 300 μl, column temperature: 40°C, and the light detection UV 210 nm (WO 2005-42593).

HPLC performed on a standard substance (heptane acid, octanoic acid, novanova acid and cekanova acid)with a known distribution coefficients 1-octanol/water, and the calibration curve is obtained for the respective elution times and the distribution coefficients of the respective standard substances. Based on this calibration curve to calculate the value of distribution coefficient (lg POW) between 1-octanol and water at the time of elution on HPLC fluorinated emulsifier. The results are shown in the table.

EEA has a small value lg POW compared with moreperformance (APFO), thus showing that his capacity for bioaccumulation is low. On the other hand, CF3CF2OCF(CF3CF2OCF(CF3)COONH4, which was synthesized in reference example 1 has a structure similar to the EEA, but the value is lg POW more than APFO, the ability to bioaccumulation which causes concern, thus showing that its accumulation in vivo is high.

In addition, in the General case, in order to judge whether accumulated or not a chemical substance in a living organism, agreed test method for determination of distribution coefficient (lg POW) between 1-octanol and water. In addition to the "Method of determination of distribution coefficient (1-octanol/ water) shake flask", as specified in the normative document OECD test 107 and in the Japanese industrial standards Z 7260-107 (2000)method is HPLC (high performance liquid chromatography), as defined and published in the normative document OECD test 117. Connection with a large value of the distribution coefficient has a greater tendency to bioaccumulation, and a connection having a small value of the distribution coefficient, has a low tendency to bioaccumulation. In the case when the value of lg POW is less than 3.5, it is considered the W as sufficient magnitude to to resolve, that this is not a high concentration, and it is also believed that bioaccumulation is small.

TABLE 1
Fluorinated emulsifierlg PO
CF3CF2OCF2CF2OCF2COONH43,13
CF3(CF2)6COONH4to 3.67
CF3CF2OCF(CF3CF2OCF(CF3)COONH44,03

Example 1

100 l stainless steel autoclave equipped with reflective wall and stirrer, load 38 g EEA, 776 g of paraffin wax and 68 l of deionized water. The air in the autoclave was replaced with nitrogen, and then reduce the pressure and load 0.6 g of methanol. Then increase the pressure by introduction of the TPV, and the temperature rises to 66°C under stirring. Then the introduction of the TPV increase the pressure up to 1.765 MPa, of 29.4 g of peroxide dinternal acid (concentration: 80 wt.%, the rest is water) dissolved in 1 l of warm water at about 70°C and injected into the autoclave. The internal pressure is reduced to 1,746 MPa approximately 1.5 min.

Polymerization Prov is implemented with the introduction of the TPV with maintaining the internal pressure of the autoclave at 1,765 MPa. The reaction ends at the moment when the number entered TPV reaches of 16.66 kg, and TPV of the autoclave is discharged into the atmosphere. Curing time is 98 minutes the resulting aqueous PTFE emulsion is cooled and ejected paraffin wax removed. The aqueous emulsion has a concentration of solids 19 wt.%. Used EEA is 2270 h/m relative to the final output of PTFE. In addition, the original average particle size of PTFE is 0,239 μm. Units in the reactor were determined approximately in trace quantities.

The specified water emulsion is diluted with pure water to a concentration of 10 wt.% and bring up to 20°C with subsequent mixing and coagulation, which results in fine powder PTFE. Then the specified fine PTFE powder is dried at 120°C. the Average particle size is 560 μm, apparent density is 0.49 g/ml, and the standard relative density is 2,219.

Comparative example 1

The polymerization is carried out in the same manner as in example 1, with the introduction of the TPV with maintaining the internal pressure of the autoclave at 1,765 MPa, except that 19 g of EEA. The polymerization rate is estimated at about 20% slower than in example 1, and when the number is entered TPV reaches 15,7 kg, abnormal reaction, i.e. Skachko brasno greater than the number entered PTFE. Therefore, the reaction is stopped after a period of polymerization 119 minutes When TPV from the autoclave discharge into the atmosphere and the autoclave is opened, remove about 4 kg units. It is believed that in the reaction with abnormal responsiveness and retrieve a large number of units of a stable emulsion polymerization is broken and it turns out water emulsion with the destruction of coagulation, resulting in polymerization shifted to suspension polymerization, having the units as a kernel.

The aqueous emulsion has a concentration of solids 14 wt.%. Used EEA is 1210 h/m relative to the total number of entered TPV. In addition, the original average particle size is 0,268 μm. The specified water emulsion is diluted with pure water to a concentration of 10 wt.% and bring up to 20°C with subsequent mixing and coagulation, which results in fine powder PTFE. Then the specified fine PTFE powder is dried at 120°C. Standard relative density is 2,219.

Example 2

100 l stainless steel autoclave equipped with reflective wall and stirrer, load 36 g EEA, 555 g of paraffin wax and 60 l of deionized water. The air in the autoclave was replaced with nitrogen, and then the pressure reduced. Increase the pressure by introduction of the TPV, and the temperature rises to°C under stirring. Then the introduction of the TPV increase the pressure up to 1.765 MPa, 26,3 g peroxide dinternal acid (concentration: 80 wt.%, the rest is water) dissolved in warm water at about 70°C and injected into the autoclave. The internal pressure is reduced to 1,746 MPa approximately for about 3 minutes

The polymerization is carried out with the introduction of the TPV with maintaining the internal pressure of the autoclave at 1,765 MPa. EEA dissolved in warm water, and only 53 of the EEA is introduced into the polymerization process. The temperature rises to 72°C halfway. The reaction is complete at the moment when the number entered TPV is 22 kg, and TPV of the autoclave is discharged into the atmosphere. Curing time is 103 minutes the resulting aqueous PTFE emulsion is cooled and ejected paraffin wax removed. The aqueous emulsion has a concentration of solids of 25 wt.%. Used EEA is 4050 h/m relative to the final output of PTFE. In addition, the original average particle size of PTFE is 0,262 μm. Units in the reactor were determined approximately in trace quantities.

The specified water emulsion is diluted with pure water to a concentration of 10 wt.% and bring up to 20°C with subsequent mixing and coagulation, which results in fine powder PTFE. Then the specified fine PTFE powder is dried at 120°C. the Average particle size is 560 μm, apparent p is otnesti is 0.48 g/ml, and the standard relative density is 2,213.

Example 3

100 l stainless steel autoclave equipped with reflective wall and stirrer, load 70 g EEA, 872 g of paraffin wax and 59 l of deionized water. The air in the autoclave was replaced with nitrogen, and then the pressure reduced. Increase the pressure by introduction of the TPV, and the temperature rises to 70°C under stirring. Then the introduction of the TPV increase the pressure up to 1.765 MPa, 5.0 g of peroxide dinternal acid (concentration: 80 wt.%, the rest is water) dissolved in 1 l of warm water at about 70°C and injected into the autoclave. The internal pressure is reduced to 1,746 MPa for about 3 minutes

The polymerization is carried out with the introduction of the TPV with maintaining the internal pressure of the autoclave at 1,765 MPa. EEA dissolved in warm water, and just in the process of polymerization is injected 125 g EEA. In addition, the ammonium sulfite is dissolved in water, and only in the polymerization process is administered 4 g of ammonium sulfite. The temperature is reduced to 64°C in the middle of the process, and it increased to 80°C at the end of the polymerization. The reaction is complete at the moment when the number entered TPV up to 23 kg, and TPV of the autoclave is discharged into the atmosphere. The polymerization is 155 minutes the resulting aqueous PTFE emulsion is cooled and ejected paraffin wax removed. The aqueous emulsion has a concentration of cordialement 26 wt.%. Used EEA is 8555 h/m relative to the final output of PTFE. In addition, the original average particle size of PTFE comprising 0.275 μm. Units in the reactor were determined approximately in trace quantities.

The specified water emulsion is diluted with pure water to a concentration of 10 wt.% and bring up to 20°C with subsequent mixing and coagulation with the obtained fine powder of PTFE. Then the specified fine PTFE powder is dried at 220°C. the Average particle size is 580 μm, apparent density is 0.49 g/ml, and the standard relative density is 2,151. In addition, in accordance with the method of measurement (E) receive extruded pasta roller. The extrusion pressure $ 21.3 MPa. Specified stretched roller is a porous material, having formed gaps and voids, and tensile strength is of 29.4 N. The relaxation time of the voltage is 564 S.

Method for producing a porous material

The porous material of PTFE according to the present invention receives through the following stages.

Pasta get by mixing fine powder of PTFE polymer with a lubricating agent such as purified (deodorized) white spirits, and then carry out the molding, in which the polymer is subjected to impacts the view of the high effort shift, thereby giving the particles of the material cohesive capability.

Next, carry out the extrusion of pastes with different cross-sectional shape, as for example in the form of a rod or tape, to the obtainment of the extrudates. For molding pastes are used, and other operations such as calendering.

Lubricating agent is removed from the obtained extrudates drying.

Not obtained sintered product is subjected to heating at a temperature of about 300°C and increase in volume by stretching in one or more directions, so that it becomes stronger, and its porosity is significantly increased.

The use upon receipt of a porous material of the modified PTFE powder according to the present invention provides excellent extrusion properties with a high degree of grinding of the powder, in particular high strength molding.

The drawing shows the structure of the thus obtained porous material. The drawing also illustrates a water-repellent properties of the material, not allowing a drop of liquid inside, however, ignores the water vapor out.

Applicability in industry.

The present invention provides aqueous emulsion of PTFE, which essentially does not contain performancenow acid or its salts and not and EET environmental problems; the fine powder of PTFE, which has excellent processability, extrusion of the paste; and a porous material. Applications can be, for example, various pipes, wire coating, sealing materials, porous membranes or filters. In addition, the product of extrusion of the paste may be, for example, the product in various forms, such as tubular, sheet-like, blankaartia, fiber-like or block.

A full description of Japanese patent application No. 2005-302340 from October 17, 2005, including the description, claims and abstract, is given here as reference in its entirety.

1. The porous material of polytetrafluoroethylene obtained by paste extrusion PTFE fine powder obtained by coagulation of aqueous PTFE emulsion obtained by carrying out emulsion polymerization of tetrafluoroethylene in aqueous medium using fluorinated emulsifier of the formula (I):
CF3CF2OCF2CF2OCF2COOA,
in which a represents an alkali metal atom or a group NH4in the amount of from 1500 to 20000 h/m relative to the final output of polytetrafluoroethylene, followed by stretching.

2. The porous material according to claim 1, in which the primary average particle size of the polytetrafluoroethylene in water polytetrafluorethylene the second emulsion is from 0.18 to 0.50 microns.

3. The porous material of claim 1, wherein the amount of fluorinated emulsifier of the formula (1) is from 2000 to 20000 h/m relative to the final output of polytetrafluoroethylene.

4. The porous material according to claim 1 in which the fluorinated emulsifier of the formula (1) is the connection CF3CF2OCF2CF2OCF2COONH4.

5. The porous material according to claim 1, in which the PTFE fine powder has a standard relative density from and 2.14 to 2.25.



 

Same patents:

FIELD: process engineering.

SUBSTANCE: invention relates to production of microporous polyolefin membranes to be sued in storage battery separators. Membrane is made from polyethylene resin, the main component, and features (a) cutout temperature of 135°C or lower whereat air permeability measured at heating at temperature rise rate of 5°C/minute reaches 1×105 s/100 cm3, (b) air permeability variation degree of 1×104 a/100 cm3/°C or higher that makes gradient of curve describing dependence of said air permeability upon temperature at air permeability of 1×104 s/100 cm3, and (c) fusion temperature of 150°C or higher whereat air permeability measured at further increase of temperature after reaching cutout temperature, again, equals 1×105 s/100 cm3.

EFFECT: well-balances air permeability variation after cutout start, low cutout temperature and better fusion properties.

11 cl, 7 dwg, 2 tbl, 13 ex

FIELD: process engineering.

SUBSTANCE: invention relates to production of microporous polyolefin membranes to be sued in storage battery separators. Membrane is made from polyethylene resin, the main component, and features (a) cutout temperature of 135°C or lower whereat air permeability measured at heating at temperature rise rate of 5°C/minute reaches 1×105 s/100 cm3, (b) air permeability variation degree of 1×104 a/100 cm3/°C or higher that makes gradient of curve describing dependence of said air permeability upon temperature at air permeability of 1×104 s/100 cm3, and (c) fusion temperature of 150°C or higher whereat air permeability measured at further increase of temperature after reaching cutout temperature, again, equals 1×105 s/100 cm3.

EFFECT: well-balances air permeability variation after cutout start, low cutout temperature and better fusion properties.

11 cl, 7 dwg, 2 tbl, 13 ex

FIELD: chemistry.

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5 cl, 3 ex, 1 tbl

FIELD: construction.

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1 dwg, 1 tbl, 2 ex

FIELD: chemistry.

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35 cl, 6 dwg, 3 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: overall, the invention relates to production of foamed thermoplastic from an aqueous dispersion for use in absorbent materials. The method involves adding at least one foam-stabilising surfactant to an aqueous dispersion which contains a thermoplastic resin, water and a stabilising agent for dispersion systems to form a mixture. Fibre is then added to the mixture which is then foamed. Further, at least a portion of water is removed from the foam to obtain foamed material with a non-cellular fibrillated morphology. The foamed material with average density between approximately 0.02 g/cm3 and approximately 0.07 g/cm3 may be used in absorbent articles.

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35 cl, 6 dwg, 3 tbl, 3 ex

FIELD: chemistry.

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20 cl, 4 dwg, 1 ex

FIELD: chemistry.

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6 cl, 1 tbl, 17 ex

FIELD: chemistry.

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20 cl, 5 ex, 5 tbl

FIELD: metallurgy.

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25 cl, 1 dwg, 1 tbl, 3 ex

FIELD: chemistry.

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12 cl, 1 tbl, 5 ex

FIELD: chemistry.

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FIELD: chemistry.

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EFFECT: fluoropolymer is useful as material with excellent heat resistance, oil resistance, chemical resistance, weather resistance, non-stickiness, anti-overgrowth properties, water-repellent properties, oil-repellent properties, solvent-repellent properties.

7 cl, 2 tbl, 14 ex

FIELD: chemistry.

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6 cl, 5 tbl, 11 ex

FIELD: polymer production.

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2 cl, 1 tbl, 4 ex

FIELD: polymers, chemical technology.

SUBSTANCE: invention relates to the continuous method for preparing polytetrafluoroethylene (PTFE) or modified PTFE finely divided powders. The continuous method for preparing PTFE or modified PTFE finely divided powders involves the following steps: (a1) dilution of PTFE-latex of modified PTFE-latex prepared in polymerization in the dispersion-emulsion to the concentration from 5 to 25 wt.-% of PTFE or modified PTFE with possible filtration of the prepared diluted latex; (b1) molding latex with inert gas to the relative pressure with respect to atmosphere pressure in the range 3-40 kg/cm2 (0.3-4 MPa); (c1) addition of acid electrolyte solution to latex in the line-flow mixer at pH value 1-4; (d1) feeding the latex flow from the mixer through capillary tube under condition of turbulent current with the Reynolds number above 3000; (e1) gel prepared at step (d1) is coagulated onto granules at mechanical stirring with the specific power 1.5-10 kWt/m3 and stirring is maintained up to flotation of finely divided powder; (f1) below water is separated from the finely divided powder. PTFE of modified PTFE finely divided powders that can't be processed by thermal method prepared by abovementioned method show the following indices: apparent density is ≥ 470 g/l; average diameter of particles (D50) is above 200 mcm; distribution of particles by diameter determined as ratio between particles mass with diameter from 0.7 to 1.3 times with respect to average particles diameter and the total particles mass above 50%. Invention provides preparing powders without using the complex and expensive equipment, and powders possess the improved fluidity and show the apparent density and narrow distribution of particles by the diameter index.

EFFECT: improved preparing method.

9 cl, 1 tbl, 1 dwg, 6 ex

The invention relates to powder rubbers containing other components to obtain vulcanizate rubber compound and method of production thereof

The invention relates to the production of emulsion rubbers in powdered form and can be used in the synthetic rubber industry
The invention relates to a method for selection of polymer coagulation

The invention relates to a method of modifying aqueous cationic dispersions of polyetherurethane (PES) used for impregnation of fabrics, fibrous bases, carpet materials, for finishing of fiberglass, as sealants, coating, etc

FIELD: chemistry.

SUBSTANCE: method involves preparation of a reactor to a polymerisation reaction, wherein said method comprises the following steps: (a) loading an inoculation layer into the reactor, (b) preliminary loading of at least one homogeneity additive, where the homogeneity additive contains a metal stearate or salt which is a metal carboxylate, and (c) carrying out a polymerisation reaction in the reactor after steps (a) and (b), including at least the initial step of the reaction in the presence of the homogeneity additive. The invention also discloses olefin polymerisation methods.

EFFECT: invention prevents stratification or formation of a precipitate during the initial polymerisation step.

38 cl, 7 dwg

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