Products made of cardboard low density

 

Approved for use in the pulp and paper industry in the manufacture of paper and paperboard low density for the manufacture of insulating vessels, such as cups. Cardboard cardboard material contains a canvas containing wood fibers and dispersed among the fibers of expanded microspheres having a theoretical density of approximately from 0.38 to 0.64 g/cm3and the sheet thickness from 609 to 889 μm, the strength of internal coupling at least about 168×10-3kJ/m2and mostly at least about 210×10-3kJ/m2. For applications such as cups, this material has on one or both sides of the barrier coating, which is mostly low-density polyethylene, designed to limit the penetration of the liquid in a cardboard canvas. The surface of the cardboard low density has a surface finish in Sheffield about 300 SU or more compared to the clean surface from 160 to 200 SU for conventional raw materials for the manufacture of cups that were considered necessary to ensure good print quality. Cardboard low density provides good quality printing on the flexographic printing machine, though the insulation and strength properties. 6 N. and 34 C.p. f-crystals, 5 Il., 3 table.

The invention in General relates to the manufacture of articles of paper and paperboard low density and to the manufacture of insulating products, and in particular relates to the production of cups made from paper and cardboard low density.

Insulating (hereinafter insulating) cups and vessels are widely used for supply of hot and cold drinks and other foods. Such products can be made of many different materials, including papapolymerou; it can be double-walled vessels and multilayer vessels on the basis of paper, such as vessels made of cardboard, with an outer layer of foamed material. Vessels based on paper are often more desirable than vessels made of materials based on styrene, since it is usually easier to make processing of materials based on paper, which are degradable by microorganisms and have a surface that is more suitable for printing. However, multi-layered and multi-walled vessels on the basis of the paper are relatively expensive to manufacture compared to products on the basis of papapolymerou and Cytoplast, are generally less expensive to manufacture compared with double-walled vessels, but their external surface is less suitable for printing.

Already attempts have been made to improve certain properties of the paper due to the introduction of paper as an expandable and non-expandable microspheres. For example, in U.S. patent No. 3556934 described the production of paper products for books, magazines, etc. in which a non-extensible microspheres injected into the composition of the paper, which then formed the canvas paper and produce drying. Microspheres expand when drying, which allows to obtain a sheet having improved density and thickness. However, in this patent are dealing with paper with relatively low core mass, which is not suitable for the manufacture of insulating vessels; in this patent there is no mention regarding the use of the obtained material for production of cardboard vessels having insulating properties, and there is no indication on how can be made of such insulating vessels, such as cups, etc.

In connection with the above, continues to exist a need in creating materials based on paper, which have good insulating properties and which are no longer up to the network to create cardboard low density, intended for use in the manufacture of insulating vessels, such as paper cups. Usually cardboard material has a cardboard sheet (hereinafter description, the terms "canvas paper and cardboard canvas" are equivalent), which contains expanded microspheres and has the bulk, which is suitable for the manufacture of insulating vessels, such as paper cups, and in this case, the cardboard is mainly the bulk in the range from approximately 325 to 358 g/m2. Cardboard low density in accordance with the present invention contains approximately from 0.25 to 10 wt.% (in terms of dry weight) of expanded microspheres and has a relatively low theoretical (apparent) density, which lies in the range approximately from 0.38 to 0.64 g/cm3and relatively high thickness of the sheet, which lies in the range from approximately 610 to 889 microns (µm). These properties are particularly suitable for cardboard products used in the manufacture of cups, in particular cups, 16 ounces of liquid (internal major diameter 5,715 cm). However, it should be borne in mind that the cardboard low density in accordance with the present invention may knight is thermal insulation.

In the manufacture of cups, when the product is intended to contain the liquid, it is preferable coating the surface of the paperboard in contact with the liquid, protective coatings, blocking the passage of fluid into the cardboard. Preferred for this task is a coating of low density polyethylene.

For cups and vessels intended for hot liquids, it is usually necessary to use a coating only on the inner surface of the cardboard vessel, and in the case of refrigerated liquids such as drinks with ice or cold drinks), when there is condensation on the outer surface, it is necessary to use a coating on both surfaces.

Cardboard in accordance with the present invention having the specified ranges of density and thickness, and intended for the production of cups, predominantly should have an average (i.e. average MD and CD) strength of inner clutch about 210×10-3kilojoules/m2- kJ/m2). The minimum strength of the inner clutch together with other properties of cardboard I need to have in order from cardboard successfully could be received cups and other similar fittings, without FotoSlate should indicate so-called "wave", which may appear on the height of the Cup during the process of molding the Cup, when the cardboard with a plastic coating covers a small similar to the rippling deformation during wrapping the blank around a mandrel to form the walls of the Cup.

Among other factors that may influence the formation of waviness in the course of the transformation operations can be mentioned a method for coating paperboard and coating weight. Thus, under normal conditions, the plastic extrusion coating (speed and weight) for the proper conversion consider it necessary to have a minimum average bending strength of the inner clutch 210×10-3kJ/m2moreover , the decrease in the rate of extrusion by 25 percent relative to the normal speed or weight gain cover approximately 50 percent of the normal weight usually allows a corresponding reduction in the minimum average strength of the inner clutch is approximately 168×10-3kJ/m2).

In accordance with the first aspect of the present invention, the surface having a coating of cardboard low density has a roughness on the scale of surface cleanliness Sheffield significantly higher than conventional raw materials for the manufacture of cha is the second printing. Thus, for a typical cardboard low density in accordance with the present invention, which is suitable for the manufacture of cups, the surface having the coating of the cardboard has a surface finish on a scale of Sheffield at least about 300SU, and surface finish PPS10 approximately 6.5 μm or less.

Cardboard low density in accordance with the present invention differs from conventional raw materials for the manufacture of cups, which calendarbut to ensure, among other things, a much higher density of about 0,704-0,769 g/cm3much lower thickness of about 508 microns, and the associated relatively smooth surface in the range from approximately 160 to 200 SU that I believe are necessary to obtain acceptable print quality. These higher density and lower the thickness of the sheet of cardboard lead to higher thermal conductivity of cardboard (that is, to decrease the desired insulation).

In accordance with another aspect of the invention, a method for manufacturing cardboard low density, suitable for use in the manufacture of insulating vessels, such as cups. This method involves the use of paper mass is 5 to 7 wt.%, in terms of dry weight, expandable microspheres, the formation of cardboard from paper pulp to the paper machine and drying and calendering the fabric to cardboard theoretical density in the range of approximately from 0.38-0.64 g/cm3and mostly about 0,416-0.64 g/cm3and thickness from approximately 610 to 889 μm, and mostly from approximately 711 to 889 microns.

In accordance with another aspect of the present invention proposes a method of manufacture of cardboard insulating vessel, such as a paper Cup. This method involves the use of paper pulp, which contains cellulose fibers and approximately from 0.25 to 10 wt.%, but mainly it is estimated that between 5 to 7 wt.%, in terms of dry weight, expandable microspheres, the formation of cardboard from paper pulp to the paper machine and drying and calendering the fabric to cardboard theoretical density in the range of approximately from 0.38 to 0.64 g/cm3and mostly about 0,416 to 0.64 g/cm3and thickness from approximately 610 to 889 μm, and mostly from approximately 711 to 889 microns, with the strength of the inner coupling at least about 169×10-3it is the Sheffield about 300 SU or higher, and then molding from a cloth cardboard vessel, such as a paper Cup that contains the canvas cardboard at least the area of the side wall of the Cup.

Cardboard web (tape), manufactured in accordance with the present invention, have high insulation properties compared with conventional single-layer cardboard canvases, and their production cost is substantially less than laminated paperboard or cardboard, having an external covering of foam. Cardboard low density can be used to manufacture cups and other insulating vessels on conventional manufacturing equipment, with minimal loss of speed equipment and with a reduced tendency to the formation of folds and other defects normal operations.

A key feature of the present invention is the use of expandable microspheres in the composition of the paper and results in a relatively low density and high thickness of a sheet of cardboard that contains extended sphere. Although previously believed that the presence of the microspheres in the composition of the paper has a deleterious effect on the physical properties of the obtained materials in some end uses, the authors of this from the tone can be easily transformed into vessels, such as insulating Cup. Not wishing to be bound by any theory, it is possible, however, to believe that suitable insulating cardboard, having a strength which is required for forming operations cups may be obtained by substantially increasing the thickness of the sheet of material and reduce its density (compared to conventional cardboard) while maintaining relatively high strength internal clutch.

These and other features and advantages of the invention will be more apparent from the subsequent detailed description of its preferred options, data as an example, do not have restrictive and described with reference to the accompanying drawings.

In Fig.1 shows the heat flow through the wall of the Cup in time for a Cup that can withstand water temperatures of 190°F.

In Fig.2 shows schematically a perspective view of the Cup of an insulating cardboard, made in accordance with the present invention.

In Fig.3 shows the cross-section area of the wall cardboard cups, made in accordance with the present invention.

In Fig.4 shows a cross section of the connection between the area of the bottom section of the side wall of the Cup in choosing the availa able scientific C with the present invention.

Insulating vessels, such as cups, are widely used for dispensing hot and cold drinks. In this case, cardboard canvases covered with an insulating layer, often provide acceptable insulating properties, however, the outer layer is usually a layer of foamed thermoplastic polymer, which increases the cost and complicates the print. Corrugated double wall cardboard vessels also usually provide sufficient insulation properties, but they are more complex and expensive to manufacture than single-layer vessels. To date failed to produce economical insulating vessel, made mainly of cardboard, which has the required strength for the operation of forming, insulating properties and has a surface for printing.

In accordance with the present invention offers an improved carton of low density, which has insulating properties, suitable for the manufacture of containers for hot and cold drinks, and which has the strength needed for the operation of molding cups.

Cardboard low density derived from paper pulp, which contains fiber solid wood, fiber soft is the first mass contains approximately 60 to 80 percent by weight, in terms of the dry weight of the fibers of the wood of firm breeds and approximately 20 to 40 percent by weight, calculated on the dry weight of soft wood fibers.

Mostly use fiber bleached Kraft pulp wood hard and soft rocks. Paper pulp also contains approximately from 0.25 to 10 percent by weight, calculated on dry weight, expandable microspheres, not primarily in the expanded state. Preferably, the microspheres comprise from approximately 5% to 7% by weight, paper weight, calculated on dry weight. In the paper composition may also include other conventional materials, such as starch, fillers, sizing chemicals and strengthening polymers. Additional fillers can be used organic and inorganic pigments, such as, for example, polymer particles such as polystyrene latex and poly (methyl methacrylate), and minerals such as calcium carbonate, kaolin and talc.

The production of paper containing expandable microspheres described generally, for example, in U.S. patent No. 3556934. Suitable expandable microspheres are of a synthetic polymeric particles, which typically have a spherical liquid-containing center. Such polymersaccharide, Acrylonitrile, vinylidenechloride, para-tert-butylstyrene, vinyl acetate, butyl acetate, styrene, methacrylic acid, vinylbenzoic, and combinations of two or more of these substances. Preferred particles are a polymer which contains approximately 65 to 90 percent by weight of vinylidenechloride, and mostly from approximately 65 to 75 percent by weight of vinylidenechloride, and approximately 35 to 10 percent by weight of Acrylonitrile, and mostly from approximately 25 to 35 percent by weight of Acrylonitrile.

The center of the expandable microspheres may contain a volatile liquid foaming agent, which mostly is not a solvent for the polymer resin. A particularly preferred foaming agent is isobutane, which can be present in an amount of approximately from 10 to 25 percent by weight of polymer particles. After heating to a temperature in the range of approximately from 80 to 190°C in the paper machine dryer polymer particles are expanded to a diameter in the range of approximately from 0.5 to 50 μm.

Conventional processes for the preparation of paper pulp (boiling, bleaching, finishing, etc) and paper production can be used the CIO is the canvas paper low density, containing expanded microspheres, mostly made in such a way that it has minimum average strength of the inner clutch (average CD and MD strength internal clutch), in combination with a reduced density and increased thickness of the sheet as compared with the conventional cardboard, which is used for the manufacture of insulating vessels, such as paper cups. This can be made known to the specialists of different measures, in isolation or in combination, allowing to increase the strength of the inner clutch cardboard canvases for a given core mass. Such measures include (but without limitation) the increase of the additive in the paper mass of wet and/or dry hardeners, such as melamineformaldehyde, polyamideimides and polyamideimide as wet hardeners, and starch, dextrins and polyacrylamides as dry hardeners, improving refining pulp and increase compression canvas paper in the press section of the papermaking machine. In addition to increasing the strength of the inner clutch increase compression canvas paper also reduces the moisture in the wet paper and allows projetoes invention taken mostly sufficient to maintain a minimum average strength of the inner clutch component of at least about 210×10-3kJ/m2). These measures are preferred at least with respect to raw materials for the manufacture of cups, which is the normal weight of the barrier coating, which is applied in the usual manner on one or both surfaces of the cups. However, the minimum strength of the inner clutch may be somewhat reduced for heavier weight of the barrier coating, which is applied in the middle and upper parts of the ordinary of 12.7-88,9 μm thickness range of the coating. For example, for a barrier coating with a thickness of more than approximately 38,1 microns minimum strength of the inner clutch about 168×10-3kJ/m2considered sufficient for acceptable quality conversion. In addition, the decrease in the rate of extrusion to approximately 25 percent also reduces the strength of the internal clutch to the same minimum level.

Among the various possibilities to increase the average strength of the inner clutch are preferred improvement of refining pulp, increasing the internal content of starch and dry hardeners and wet compression canvas paper during its production to a level below the crushing of the sheet, and HC the sizing press.

Introduction to pulp expandable microspheres are unexpanded condition leads to a reduction of theoretical density of the obtained dry cardboard. However, found that the decrease in the density of cardboard due to the introduction of expanded microspheres have a deleterious effect on the possibility of forming cardboard cups and other vessels. In accordance with the present invention has determined that the cardboard low density, which contains expanded microspheres obtained in a relatively narrow range of densities and thicknesses of the sheets, in combination with the above high strength internal clutch, has the physical properties required for treatment at various converting operations. This cardboard has significantly improved insulating properties compared to conventional raw materials for the manufacture of cups and double wall vessels, and has insulating properties comparable to vessels having an outer layer of foam, but at a much lower cost. For example, cardboard low density in accordance with the present invention has an R value of about 0,0132 m2K/W, compared with an R value of about 0,0132 m2K/W for conventional raw materials for the manufacture of cups, however, is, the accordance with the first embodiment of the present invention cardboard canvas, which contains expandable microspheres, dried and calendarbut on the paper machine to achieve theoretical density in the range of approximately from 0.38 to 0.64 g/cm3andthickness in the range of approximately from 609 to 889 microns. As has been described here previously, the fabric is paper, which contains expanded microspheres introduced between the fibers, mainly derived from the pulp and/or paper pulp thus treated so that the sheet of paper had an average strength of the inner coupling at least about 168×10-3kJ/m2for cardboard with a heavier coating (i.e. over approximately 38,1 mm to a maximum of approximately 88,9 mm) and at least about 210×10-3kJ/m2on average for the cardboard with a lighter coating (that is, approximately from 12.7 to 38.1 microns). Cardboard canvas, which contains expanded microspheres and has a density and thickness outside of these ranges, or in which of these bands has the strength of internal clutch below 168×10-3kJ/m2) I think not suitable for mass forming what was to mould Cup on the existing equipment for the production of cups, with minimal alterations to the equipment or no.

As for the other physical properties required for the manufacture of cups, cloth cardboard low density in accordance with the present invention will generally have a minimum tensile strength, which is determined in accordance with test Tappi Standard Test T, which is about 5.25 kN and the minimum value of the average CD stretching of the substrate, which is determined in accordance with Tappi test Standard Test T494 of about 3.3 percent.

An additional feature of the present invention is that the carton of low density has a roughness of at least about 300 on the scale of surface cleanliness Sheffield, but provides comparable print quality during the operation of flexographic printing. The opportunity for a good print on the cardboard is quite unexpected, as usual cardboard, such as those used as raw materials for the manufacture of cups, usually calendarbut to a thickness of about 508 μm to obtain a surface finish (uncoated) from approximately 125 to 200 SU (and clean the surface before calendering is over 400 SU), which is considered necessary for acceptable print quality.

That is antervasna only from 609 to 889 microns (and mostly from approximately 711 to 889 μm) and at a density of approximately from 0.38 to 0.64 g/cm3(mostly approximately from 0.41 to 0.64 g/cm3when remains relatively rough surface with a surface finish in Sheffield (uncoated) approximately 300 SU or higher (usually approximately from 320 to 350 SU) and surface cleanliness PPS10 less than approximately 6.5 microns has a surprisingly beneficial effect on the print quality and the process of making cups from a cardboard. Not wishing to be bound by any theory, it is possible, however, to believe that the quality of the printing on the cardboard because of its higher ability to undergo compression, which allows to obtain better printing options on the flexographic machine.

As mentioned here previously, cardboard, made in accordance with the present invention is particularly well suited for molding cups with good insulation properties. These cups are usually made of blanks for the manufacture of cups, which has a barrier coating on one or both sides. Cups that are designed for hot beverages such as coffee, soup and other hot products usually are coated only on the inside, so that the workpiece for the manufacture of such cups in accordance with the present invention may have a defence the information or picture. In the finished Cup coated side is on the inside.

Cups designed for cold drinks, are typically made blanks for the manufacture of cups coated on both sides, and a seal put on one of the layers of the coating. Thus, the blanks for the manufacture of such cups in accordance with the present invention may have a barrier coating on both sides, and the side without print is on the inside. In the cups, intended for cold drinks, external barrier coating prevents formed on the outer surface of the condensate in a substrate made of cardboard and its possible weakening.

Any suitable barrier coating can be used for thermal insulation of vessels, such as cups. Despite the fact that the plastic coating of low density in accordance with the present invention are preferred for use in such products can also be used natural and synthetic chemical systems, such as coatings on the basis of starch and coatings based on polyvinyl alcohol, and stained with pigment coatings that contain organic and inorganic pigments (dyes), which are necessary for this application. Coatings can be applied using conventional means, and in the case of polyethylene, they can be deposited on the surface of the cardboard low density by means of extrusion lamination, or by laminating a pre-formed film. The coating thickness typically ranges approximately from 12.7 to 88.9 μm, and is preferably about 38,1 μm for the inner surface of the vessel or Cup and about 25.4 μm for the outer surface.

Specific and particularly preferred cardboard low density in accordance with the present invention is a carton of low density, which contains a cardboard canvas containing expanded microspheres having a theoretical density 0,448 g/cm3the thickness of the sheet 711,2, μm surface finish in Sheffield at least 300 SU, PPS10 surface finish 6.5 μm or less, the tensile strength (transverse direction) of 5.25 kN/m and the strength of the inner clutch (in transverse direction) 189×10-3kJ/m2. This cardboard has a basic weight of 325 g/m2and the content of the microspheres from 5 to 6 wt.% in terms of dry weight linen paper. Low-density polyethylene by means of extrusion lamination applied to any molded cups and get the R value of about 0,0123 m2K/W.

Note again that the cardboard low density in accordance with the present invention can successfully be used for the manufacture of various products, including (but not limited to, cardboard cups and other vessels that may contain warm, hot or cold foods or drinks, when there is a need in isolation and at least in the short-term barrier properties. When used to manufacture cups (priority given application) section of the bottom is usually a flat single item and may not be formed of an insulating cardboard low density, obtained in accordance with the present invention, which depends on economic and other factors.

Note that if the serial molded cups some conventional packaging machines are designed to work only in a narrow range of thicknesses of cardboard sheets. As the insulating Board in accordance with the present invention may be thicker than the standard workpiece for the manufacture of cups (for a given core mass), increasing the thickness of the sheet may require the use of new or modified equipment. In such situations, the present invention allows proizvoditeli cutting for education procurement), that allows the use of conventional equipment.

An example is the horizontal seam of the package or Cup. Given the bulk of the insulating Board in accordance with the present invention has the sheet thickness is much larger than the standard cardboard, so the horizontal seam may be too thick for some common transformation operations. Due to the compression of the horizontal seam under high pressure, the thickness can be reduced to almost the thickness of a sheet of ordinary cardboard (usually to a thickness of about 508 microns). This process is commonly referred to as "compression", and it can be considered as a preliminary processing of the finished carton low density (i.e. cardboard and coated), which facilitates its use for shaping cardboard cups and other vessels having one or more invoices seams.

Some types of compression operation can be carried out at the site of the workpiece, which is used for the manufacture of the rim of the Cup or vessel in the form of baths to reduce the final thickness of the rim. This improves the aesthetic appearance due to the smaller diameter of the rim or allows the use of existing cover for cups or vessels in view of the same cylinder. Usually use a folding cardboard 360 degrees.

It should also be borne in mind that the minimum diameter of the cylinder rim usually depends on the thickness of the cardboard. For example, during the normal manufacturing process, the diameter of the rim (diameter cylinder, which is obtained by coagulation of a portion of the workpiece with the formation of the bezel, which is the upper edge of the Cup) is usually 7 times greater than the thickness of the sheet of cardboard. If the upper portion of the rim compress to reduce the thickness of the sheet, the diameter of the cylinder's rim may also be reduced. The preparation section, which is formed by the bezel, can be compressed to reduce the whole of its diameter or can be compressed by means of a number of parallel passages, which contributes to subsequent deformation.

Under some compression technologies can be applied to horizontal seam after its formation to reduce its full thickness.

Additional aspects, advantages and features of the present invention can be ascertained from the following examples, which are not restrictive. In these examples was used cardboard with LDPE coating for molding the preform side wall for cups, manufactured on a machine for the production of cups, being the ment, which is typically approximately 5-20 percent of the total weight of the cardboard, when, for example, material LDPE put through extrusion laminating on one surface of the cardboard with a thickness of about 38,1 mm.

Example 1. In the following examples were obtained samples of cardboard of low density, containing microspheres, and the results of their comparison with a control sample that does not contain microspheres. Expandable microspheres that are injected into the pulp obtained from the company Expancel, Inc. of Duluth, USA, GA (trade name EXPANCEL). The specified thickness of the sheet samples were 483 microns to simulate the thickness of a sheet of conventional raw materials for the manufacture of cups. After receiving the cardboard it was sent to the extruder for extrusion coating low density polyethylene with a speed of 239 g/m2to obtain barrier coating on one side, having a thickness of about 25.4 μm. All samples, except for sample D, contain a polyethylene coating. Sample D has insufficient strength and is too fragile for extrusion coating with polyethylene. Polyethylene coated samples were used for molding 16-uncivic cups for serial installation for the production of cups. Isolatio is, is filled with hot water with a temperature of 190°F. the Appropriate properties of the samples made of cardboard low density are shown in Table 1.

Of the samples allocated Sample G, which has a very high insulating properties. The average time during which people can keep hot Cup made from sample G is 29 seconds, while it takes 11 seconds for the control sample. While Sample G has excellent insulating properties, low basic weight cardboard leads to a low rigidity, so made from such a cardboard Cup has low rigidity (structural stability). However, rigidity is an essential characteristic for a Cup, so you need to improve the rigidity of the raw materials for the manufacture of cups. Sample M, which has a density 0,429 g/cm3and the average strength of the inner clutch 191×10-3kJ/m2may be subject to processing by extrusion lines and converted into cups. Board stiffness of this sample was slightly improved compared with the hardness of Sample G. Sample of M also has better insulating properties than the control sample, which has a density of 0.66 g/cm3.

Durable is a component of at least about 210×10-3kJ/m2but it still allows the conversion if the lesser strength of the inner clutch, as has been mentioned here before, is acceptable at somewhat reduced speed of the extruder and/or by increasing the weight of the barrier coating.

The density of the Sample D was too low for carrying out processing of the canvas paper. The density of the Sample D was 0,147 g/cm3and the average strength of the inner clutch was 103×10-3kJ/m2. Found that the strength of the inner clutch is too low for processing cloth paper in extrusion installation for coating or for the operation of the molding Cup.

Apparent thermal conductivity of cardboard low density was measured using methods Guarded Heat Flow Method (ASTM C177). The results show mainly a linear relationship between density and thermal conductivity, and cardboard with a higher density has a higher conductivity (i.e. provides the worst insulation).

Example 2. In this example, two different source cardboard low density in the range of approximately from 0.38 to 0.64 g/cm3were made from paper pulp, the cat who their properties in the original cardboard are shown in Table 2. All samples in Table 2 contain printed on the extrusion line coating of low density polyethylene and have a print made on water flexo press. The coating thickness of 508 μm was deposited on one side of the cardboard, and the printing was done on the other side.

Paperboard coated, specified as Sample 19 was used for the manufacture of cups for serial installation with an existing snap-in. Cardboard, specified as a Sample of 32 was used for the manufacture of cups for serial installation with experimental snap. Using experimental snap managed to get only partially molded rim of the Cup. Modification of the snap-in allows you to get fully molded cups.

Of the samples allocated Sample 32, which has a very high insulating properties. The average time during which people can keep hot Cup made from the sample 32 is 37 seconds, while it takes 11 seconds for the control sample. Moreover, the relatively high stiffness of the cardboard Pattern 32 shown in the table, results in a corresponding (higher stiffness compared to the standard cardboard. The stiffness of a sample of 32 su the C source cardboard, were determined by measuring the temperature of the side wall of the Cup containing hot liquid. Note that the maximum value of the temperature of the side wall of the Cup containing hot liquid, is a typical characteristic for insulating Cup. Sensory perception of heat determines the time during which the tissue is human skin can tolerate touching the side wall hot cups. Skin temperature is a function of the heat flow in the tissue of the Cup and the internal dissipation of heat (heat sink) in the tissue. Heat flow in the tissue is a combination of many factors, including thermal properties of the cardboard, the temperature of the liquid and the contact resistance between the fabric and the outer wall of the Cup. I believe that the rigidity of the Cup and the surface roughness (i.e. texture) also affect the perception of warmth, acting on the effective area of contact between the side walls of the Cup and cloth.

In Fig.1 shows a graph of heat flow wall in time for a Cup of water having a temperature of 190°F. Shown in Fig.1 the data were obtained through the application of pressure to the flow sensor. In Fig.1 curve a corresponds to the Cup, made from the Sample 32 (Tablewise layer, curve C corresponds to the usual double-walled Cup, and the control curve corresponds to the usual single-walled Cup without isolation.

It can be assumed that shown in Fig, 1 the data relatively accurately reflect the results of measurement of heat flowing into the fabric, for a Cup, which is held in the hand at normal pressure retention. The measurements were stopped at the point of detection of excessive warmth.

As shown in the curves of Fig.1, Cup, made of cardboard Sample 32 (curve A), has insulating properties comparable to a Cup made in accordance with U.S. patent No. 4435344 (curve B). In this regard, we note that the Cup in accordance with curve b was obtained by covering the outer wall of thermoplastic resin, which was then foamed. However, the process of manufacture of cups in accordance with the curve In requires additional equipment for treatment, and a thermoplastic coating adversely affects the print quality and pleasantness of the surface of the Cup for hands to the touch. In contrast, cups, made of cardboard Sample 32, have no external thermoplastic cover (cover only available on the internal surface and the user has the feeling that the traditional properties than conventional double-walled Cup according to the curve C.

Example 3. In this example, there were prepared 8 original cartons low density, which have a density in the range of approximately from 0.38 to 0.64 g/cm3and paper pulp contains expandable microspheres. Then, from these original cartoons did 16-oz can Cup. Physical properties of the original cardboard are shown in Table 3. All samples in Table 3 contain printed on the extrusion line coating of low density polyethylene and have a print made on water flexo press. A coating thickness of about 38,1 mm was deposited on one side of the cardboard, and the seal was applied directly to another surface.

Samples PI and P2 were made on the pilot paper machine and subjected to extrusion at the experimental extruder, while the samples C1-C5 were made on the paper machine serial. In either case, paper pulp, which is used for manufacturing these samples contain a mixture of wood pulp from hardwood and soft wood, as well as moisturizing (wet-end, "wet end") chemicals, such as starch, dry reinforcers and a corresponding number of extensible mi the sequence of chemicals varied to achieve a given range of the strengths of the internal clutch. After extrusion of polyethylene and transformation in Cup, was made an external examination and classification of cups on MD waviness or the presence of folds (wrinkles), that allows to judge about the potential conversion of cardboard coated. Samples with a high degree of waviness cannot be used as a commercial product.

Samples PI and S1 correspond to the condition in which the strength of the inner clutch lies below the minimum 168×10-3kJ/m2. Under this condition, these samples have a strong MD waviness and may not be used as a commercial product. Sample P2 corresponds to the condition in which the density cardboard significantly lower than the density of ordinary cardboard, which is used for the production of cups, however, due to its high strength inner clutch this product does not have MD waviness. Sample S2 has some degree of waviness, because its strength inner clutch component 170×10-3kJ/m2is the lower limit of the preferable range of the strengths of the internal clutch. Samples C3, C4, and C5 have preferred levels of density and strength of the inner clutch.

Samples PI and S1 soot lies below the minimum 168×10-3kJ/m2. Under these conditions, these samples have a strong MD waviness and may not be used as a commercial product. Sample P2 corresponds to the condition in which the density cardboard significantly lower than the density of ordinary cardboard, which is used for the production of cups, however, due to the high strength inner clutch this product does not have MD waviness. Sample S2 has some degree of waviness, because its strength inner clutch component 170×10-3kJ/m2is the lower limit of the preferable range of the strengths of the internal clutch. Samples C3, C4, and C5 have preferred levels of density and strength of the inner clutch.

The preceding examples show that in the range of theoretical density of approximately from 0.38 to 0.64 g/cm3and the thickness of the sheets in the range of approximately from 609 to 889 mil, in combination with relatively high strength internal clutch, over at least about 168×10-3kJ/m2physical properties of cardboard low density suitable for the processing of raw materials for the manufacture of cups, allowing you to do an insulating Cup.

Cups usually ship is so the outer edge of the bottom of one Cup abuts the inner base of the other Cup, which is under it. This requirement, together with the desired internal volume of the Cup and aesthetic requirements, creates additional restrictions on the permissible thickness of the cardboard. For example, the thickness of the sheet workpiece 16-Unaway Cup predominantly should not exceed approximately 889 microns. In this regard, the upper limit of the thickness of the workpiece 16-Unaway Cup is preferably about 813 mm.

In the process of forming cloth paper cloth paper that contains expandable microspheres, mostly pressed for higher solids content than the canvas paper, which does not contain microspheres.

After pressing and drying the wet paper calendarbut to a thickness that provides the desired density and thickness of the sheet within the ranges shown above for cardboard low density in accordance with the present invention. For the calender of iarovaia can be used Multiroll calender, but mainly use the device for calendarlivonia with the extended heated zone of capture, with long capture zone or Shoe with grip, which provide the so use the installation for calendarlivonia with one or more elongated zones of capture, which is the exposure time in the range of approximately from 2 to 10 µs and a peak pressure of capturing less than approximately 1200 psi.

With reference to Fig.2-5 shows the embodiment of the Cup 10 made of an insulating cardboard low density in accordance with the present invention, having the form of an inverted truncated cone.

The Cup 10 has a mainly cylindrical wall section 12 having a vertical seam lap 14 connecting the end edges 16 and 18 of cardboard canvas, forming a wall section 12. End edges 16 and 18 can be attached to each other using conventional means, such as adhesives, termokleevuyu coating and other known means. The Cup 10 also has an annular curled rim 20 and a separate main circular area of the bottom 22, which connect and fasten to the wall section 12 around the perimeter. In Fig.4 shows the method of attaching area of the bottom 22 to the wall section, and Fig.5 shows twisted (folded) rim 20 of the Cup in accordance with the present invention.

As shown in Fig.3, the wall section 12 of the Cup 10 is made of insulating the, dispergirovaniya in the fibrous matrix of cardboard. Microspheres 24 mostly are mostly hollow and impart insulating properties to the areas of the walls and the bottom 12, 22 of the Cup 10. However, the bottom 22 may be made of plain cardboard with a coating to reduce the cost of the product, since heat generation is not of great importance, because the user usually does not touch the bottom when holding the Cup.

Due to the increased thickness of the cardboard used for the formation wall sections and a bottom 12, 22 of the Cup 10 may require modifications to conventional equipment and/or cardboard to perform folds and rolls needed to build sections of the cups together. Previously there have already been described operations pre-processing for changing the thickness of the sheet sections of cardboard ("compression"), which allow for ease of molding and assembling of cups.

As shown in Fig.4, the lower end 26 of the wall section 12 is bent along the seam groove 28 in order to create a mainly V-shaped pocket 30. The end 22 of the section of the bottom of the bend along the junction 34 to create a running mainly at right angle valve 36 (which may be compressed during operation pre-processing), which is included in the pocket 30. Valve is litsevoy the upper end 38 of the wall section 12 (which may be compressed during operation pre-treatment), mostly collapsed, as shown in Fig.5, to receive the ring rolled rim 20. Tooling required for forming a folded rim 20, you may also need to be changed due to the increased thickness of the cardboard used to make the wall section 12, in particular, if the region of the upper end 33 of which do the bezel 20 is not compressed during the operation of pre-processing. Rolled rim 20 has a strengthening of the upper section of the Cup, allowing you to keep it fluid and limit the formation of drops, and it provides a more comfortable edge for engagement by the lips.

Again it should be emphasized that the internal and possibly external surface of the Cup 10 may be of conventional barrier coatings to reduce the porosity of the Cup, so that the fluid is not leaked to a cardboard substrate wall sections and a bottom 12, 22. As the coatings can be used one or more layers of such polymeric materials such as polyethylene (mainly low density polyethylene), EVOH, polyethylene terephthalate, etc. which are usually used in such applications.

Despite the fact that there were described some exemplary embodiments of the invention, it is clear that in n the framework of the following claims.

Claims

1. Cardboard material for the manufacture of cardboard receptacles, such as paper cups, which contains a cardboard canvas containing wood fibers and dispersed among the fibers of expanded microspheres having a theoretical density of approximately from 0.38 to 0.64 g/cm3and the sheet thickness from 609 to 889 μm, the strength of internal coupling at least about 168·10-3kJ/m2.

2. Cardboard material under item 1, in which the density of the cardboard blade is at least about 0,416 g/cm3and the thickness of the cardboard sheet of fabric is at least about 711 microns.

3. Cardboard material under item 2, characterized in that the average strength of the inner clutch cardboard blade is at least about 210·10-3kJ/m2.

4. Cardboard material under item 1, characterized in that the average strength of the inner clutch cardboard blade is at least about 210·10-3kJ/m

5. Cardboard of matcha least about 168·10-3kJ/m2.

6. Cardboard material under item 1, characterized in that it further comprises a barrier coating on at least one surface of the cardboard canvas.

7. Cardboard material under item 6, wherein the barrier coating is present only on the surface of the cardboard canvases, located inside the Cup.

8. Cardboard material under item 6, wherein the barrier coating has an average thickness of approximately from 12.7 to 88.9 microns.

9. Cardboard material under item 6, wherein the barrier coating includes a coating material selected from the group comprising polyethylene, EVON and polyethylene terephthalate, and has an average thickness in the range of approximately from 12.7 to 88.9 microns.

10. Cardboard material under item 6, wherein the barrier coating includes a low-density polyethylene and has an average thickness of approximately from 25.4 to 88.9 microns.

11. Cardboard material under item 6, wherein the barrier coating is present on both surfaces of the cardboard canvas.

12. Cardboard material under item 1, characterized in that the cardboard surface has a surface finish in Sheffield at least about 300 SU.

13. Cardboard material under item 1, characterized in that the cardboard Polo is specified material has printed information, applied directly to the surface.

14. Cardboard material under item 1, characterized in that the cardboard canvas has one surface with a surface finish in Sheffield at least about 300 SU and PPS purity of about 6.5 μm or less, and this material has printed information printed directly on the surface.

15. Cardboard material under item 1, characterized in that the cellulose fibres in a cardboard canvas contain approximately 20 to 40% by weight, calculated on the dry weight of soft wood fibers and approximately 60 to 80% by weight, calculated on the dry weight of the fibers of solid wood.

16. Cardboard material under item 1, wherein the expanded microspheres in a cardboard canvas are synthetic polymeric microspheres that comprise approximately from 0.25 to 10 wt.% of the total weight cardboard canvases, in terms of dry weight.

17. Cardboard material under item 1, wherein the expanded microspheres in a cardboard canvas are synthetic polymeric microspheres, which constitute approximately 5 to 7 wt.% of the total weight cardboard canvases, in terms of dry weight.

18. Cardboard material for the manufacture sorowako from 5 to 10 wt.% of the total weight of cardboard canvas in terms of dry weight, expanded synthetic polymeric microspheres dispersed among the fibers having a theoretical density of approximately from 0.38 to 0.64 g/cm3, the sheet thickness is approximately from 609 to 889 μm, the average strength of the inner coupling at least about 168·10-3kJ/m, the surface finish on the Sheffield about 300 SU or higher, and barrier coating, having a thickness of approximately from 12.7 to 88.9 μm at least on one surface of the cardboard canvas.

19. Cardboard material under item 18, characterized in that it further has printed information printed directly on at least one surface of the cardboard canvas.

20. Collected paper vessel, which has a side wall and a bottom, tightly connected to each other, in which the side wall is made of cardboard material, which contains a cardboard canvas containing wood fibers and approximately 5 to 10 wt.% of the total weight cardboard canvases, in terms of dry weight, expanded synthetic polymeric microspheres dispersed among the fibers having a theoretical density of approximately from 0.38 to 0.64 g/cm3, the sheet thickness is approximately from 609 to 889 μm, average to about Sheffield SU 300 or more and barrier coating, having a thickness of approximately from 12.7 to 88.9 μm at least on one surface of the cardboard canvas.

21. Collected paper Cup, which has a side wall and a bottom, tightly connected to each other, in which the side wall is made of cardboard material, which contains a cardboard canvas containing wood fibers and approximately 5 to 10 wt.% of the total weight cardboard canvases, in terms of dry weight, expanded synthetic polymeric microspheres dispersed among the fibers having a theoretical density of approximately from 0.38 to 0.64 g/cm3, the sheet thickness is approximately from 609 to 889 μm, the average strength of the inner coupling at least about 168·10-3kJ/m2clean the surface by about Sheffield SU 300 or more, and barrier coating, having a thickness of approximately from 12.7 to 88.9 μm at least on one surface of the cardboard canvas.

22. A method of manufacturing a carton of low density for the manufacture of insulating vessel such as a Cup, which involves the use of paper pulp containing cellulose fibers and approximately 0.25 to 10% by weight, calculated on dry weight, extensible microga cloth to a thickness of approximately from 609 to 889 microns and a density in the range of approximately from 0.38 to 0.64 g/cm3.

23. The method according to p. 22, characterized in that the density of the cardboard blade is at least about 0,416 g/cm3and the thickness of the cardboard sheet of fabric is at least about 711 microns.

24. The method according to p. 23, characterized in that the strength of the inner clutch cardboard blade is at least about 210·10-3kJ/m2.

25. The method according to p. 22, characterized in that the strength of the inner clutch cardboard blade is at least about 210·10-3kJ/m2.

26. The method according to p. 22, characterized in that the strength of the inner clutch cardboard blade is at least about 168·10-3kJ/m2.

27. The method according to p. 22, characterized in that it further involves the application of a barrier coating on at least one surface of the calendered cardboard canvas.

28. The method according to p. 27, wherein the barrier coating is present only on the surface of the cardboard canvases, located inside the vessel.

29. The method according to p. 27, wherein the barrier coating has an average thickness of approximately from 12.7 to 88.9 microns.

30. The method according to p. 27, wherein the barrier coating includes coating the area roughly from 12.7 to 88.9 microns.

31. The method according to p. 30, wherein the barrier coating includes a low-density polyethylene and has an average thickness of approximately from 25.4 to 76,2 mm.

32. The method according to p. 27, wherein the barrier coating is present on both surfaces of the cardboard canvas.

33. The method according to p. 22, characterized in that the cardboard surface has a surface finish in Sheffield at least about 300 SU.

34. The method according to p. 22, characterized in that the cardboard canvas calendarbut so it had a clean surface to Sheffield at least about 300 SU, and the method further involves the application of printed information directly on the cardboard surface of the canvas.

35. The method according to p. 22, characterized in that it further involves the application of printed information directly on the surface of the cardboard canvases, located on the outer side of the vessel, the surface of which bears printed information has a surface finish in Sheffield at least about 300 SU PPS10 and the cleanliness of the surface is about 6.5 μm or less.

36. The method according to p. 22, characterized in that the pulp contains approximately 5 to 7 wt.%, in terms of dry weight, expandable microspheres.

37. SPO is the use of cardboard material, having a cardboard canvas containing approximately from 0.25 to 10% by weight, calculated on the dry weight of expanded polymeric microspheres having a sheet thickness of approximately from 609 to 889 μm, theoretical density of approximately from 0,416 to 0,649 g/cm3the inner strength of adhesion of at least about 168·10-3kJ/m2and surface finish in Sheffield at least about 300 SU, and having a barrier coating on at least one surface of the cardboard cloth having a thickness of approximately from 12.7 to 88.9 microns, forming at least a side wall of the Cup from a cardboard canvas, the surface of the cardboard canvases with a barrier, facing the inside of the Cup, and the other surface of the cardboard blade facing outwards, and sealing compounds of the side wall with the bottom.

38. The method according to p. 37, characterized in that the cardboard surface has a barrier coating on both surfaces facing the inside of the Cup and out.

39. The method according to p. 38, characterized in that the cardboard canvas has a seal on the barrier coating, on the surface located on the outside of the Cup.

40. The method according to p. 37, characterized in that the cardboard surface has a barrier coating only on the surface the side of the Cup.



 

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