WO2000076322A1

WO2000076322A1 - Material compositions for the production of adhesion-reducing cellulose composites

Info

Publication number: WO2000076322A1
Application number: PCT/GB2000/001812
Authority: WO
Inventors: Lei Jong
Original assignee: Devro Ltd; Teepak Investments Inc
Current assignee: Devro Ltd; Teepak Investments Inc
Priority date: 1999-06-15
Filing date: 2000-05-11
Publication date: 2000-12-21
Anticipated expiration: 2001-12-15
Also published as: EP1189516A1; AU4770200A; CZ20014506A3

Abstract

A cellulose composite composition including hydrophobic wax, carboxy containing anionic polymer, and cellulose. The composite composition is formed by the coagulation, regeneration and drying of a mixture consisting of hydrophobic wax emulsion, carboxy containing anionic polymer emulsion, and viscose. The composite has a hydrophobic surface with reduced adhesion to hydrophilic surfaces when compared with regenerated cellulose alone or when compared with cellulose including paraffin wax alone or cellulose including carboxy containing anionic polymer alone. The composition is thus a synergistic cellulose containing composition having a lower adhesion to a hydrophilic surface than cellulose with or without the other individual components of the composition. The composition is prepared by precipitation (coagulation and/or regeneration) from a mixture comprising hydrophobic wax emulsion, anionic polymer emulsion and viscose. The regenerated product is then dried to obtain a composite material having a hydrophobic surface.

Description

MATERIAL COMPOSITIONS FOR THE PRODUCTION OF ADHESION-REDUCING CELLULOSE COMPOSITES

This invention is related to a material composition based on regenerated cellulose for adhesion-reducing applications, especially adhesion towards hydrophilic substances such as polyamides, meat emulsions, proteins, polyacrylic acids, polyvinyl alcohols, and so on. It is well known that cellulose comprises many hydrophilic hydroxy groups and that cellulose readily adheres to hydrophilic materials as above described. It is also known that hydrophilic substances do not wet and adhere to a hydrophobic substrate.

U.S. Patent 3,224,885 describes the incorporation of alkyl ketene dimers into cellulose. A ketene dimer content between 0.1 and 10 percent by the weight of cellulose in the viscose is effective in imparting improved peelability from the sausage meat surface. Solid alkyl ketene dimers can be added to the viscose in the form of aqueous emulsion containing emulsifying agents. The ketene dimer containing viscose compositions were all extruded onto a paper web within about 10 minutes after viscose and the ketene dimer had been mixed. The tube after impregnation and coating with the viscose was passed through a bath containing sodium sulfate, sulfuric acid, and ammonium sulfate. The resultant regenerated cellulose tubing was washed, plasticized and dried. U.S. Patent 4,163,463 and U.S. Patent 4,141,749 describe the incorporation of oxazoline wax into cellulose. The oxazoline wax is incorporated into viscose in a proportion from about 1-20% by weight of the cellulose content in the viscose, the oxazoline impregnated viscose was extruded into a tubular casing, coagulated, and the cellulose regenerated. The cellulose composite had reduced adhesion towards a sausage meat surface.

Cellulose fiber reinforced polyethylene composite has been used as a means to improve the stiffness of polyethylene. However, without surface modifications on cellulose fiber, polyethylene, or both, interfacial bonding appears to be unfavored. When the cellulose fiber surface is modified by maleated polypropylene grafts, the fiber is converted to a predominantly dispersion-force solid. Such surface modified fibers improve the elastic and storage moduli when used in polypropylene, polystyrene or chlorinated polyethylene composite.

Most current methods for modifying cellulose surfaces involve coating an emulsion onto the regenerated cellulose surface. U.S. Patent 3,106,471 and U.S. Patent 3,158,492 for example describe the coating of regenerated cellulose surfaces with alkyl ketene dimer emulsion to produce an adhesion-reducing surface for easy detachment from a sausage meat surface.

None of the above described methods or products resulted in a reduction of adhesion of cellulosic products to polar substances, such as sausage meats, that is as good as desired. In accordance with the invention a cellulose composite composition is provided that includes paraffin wax, carboxy containing anionic polymer, and cellulose. The composite composition is formed by the coagulation, regeneration and drying of a mixture consisting of paraffin wax emulsion, carboxy containing anionic polymer emulsion, and viscose. The composite has a hydrophobic surface with reduced adhesion to hydrophilic surfaces when compared with regenerated cellulose alone or when compared with cellulose including paraffin wax alone or cellulose including carboxy containing anionic polymer alone. The composition is thus a synergistic cellulose containing composition having a lower adhesion to a hydrophilic surface than cellulose with or without the other individual components of the composition. The composition is prepared by coagulation and regeneration of a mixture comprising a hydrophobic wax, e.g. paraffin wax, emulsion; anionic polymer emulsion; and viscose. The regenerated product is then dried to obtain a cellulose product having a hydrophobic surface. Surprisingly, in accordance with the invention, neither carboxylic acid containing polymer nor wax alone, when mixed with cellulose, can produce the same degree of hydrophobic surface as the combination of both at the same total weight fraction in the cellulose composite. For example a cellulose composite containing 30% of 2:1 mixture of poly (ethylene-acrylic acid) and wax has a more hydrophobic surface towards the polypeptide than a cellulose composite containing 30% of wax or 30% of poly (ethylene-acrylic acid) . In addition to the aforementioned hydrophobic surface, the current process is a one-step process instead of a two-step coating process first requiring regeneration of a cellulose surface followed by a coating process.

According to the current invention the cellulose composite contains carboxylic acid containing polymer (a) , wax (b) , and cellulose (c) . Polymer (a) is introduced as an emulsion in the form of an aqueous dispersion of carboxylic acid containing polymer neutralized with an alkaline material such as potassium hydroxide, sodium hydroxide, or ammonium hydroxide. The wax (b) is the aqueous dispersion of wax through the action of surfactants which can be anionic, cationic, or nonionic. Component

(c) is in the form of viscose that is the aqueous solution of cellulose in CS₂, in the presence of an aqueous alkali metal hydroxide such as sodium hydroxide. Aqueous solution of components (a) , (b) , and (c) results in a material that can be coagulated by the well known acid/salt regeneration solution process.

"Carboxy" group, as used herein means a carboxylic acid group or a carboxylic acid salt group.

"Viscose" as used herein means traditional xanthate viscose formed by dissolution of alkali cellulose in carbon disulfide as well as other solutions of cellulose that can be precipitated or regenerated, such as cupraammonium cellulose, cellulose aminomethanate, and cellulose-tertiary amine oxide solutions .

The composite compositions of the invention may be prepared by mixing together effective amounts of anionic polymer emulsion, wax emulsion, and viscose, e.g. xanthate solution in an aqueous environment to obtain a solution from which cellulose may be precipitated. Precipitated, as used herein means either precipitation of non- derivatized cellulose from a solution, e.g. cellulose in a cupraammonium solution or an amine oxide solution, or by coagulation of a derivatized cellulose, e.g. xanthate cellulose or cellulose aminomethanate; followed by regeneration to remove derivatizing groups. The precipitated cellulose encloses the anionic polymer and wax to form a solid cellulose composite. Upon the removal of water from the swollen cellulose composite, the surface of the composite becomes hydrophobic, substantially reducing wetting and adhesion by hydrophilic substances.

As used herein, unless otherwise noted, the weight percentages of the components of the composition are based on the total dry weight of the compositions.

Anionic polymers suitable for practicing this invention typically are hydrocarbon polymers containing a few percent of carboxylic acid functional groups or their salts (carboxy groups) . These hydrocarbon polymers are synthesized by free radical, anionic, cationic, or emulsion polymerization of unsaturated monomers with a few percent of carboxy containing unsaturated monomers . The carboxy functional groups may or may not be protected during the polymerization process, depending on the reaction used in polymer formation. The desired percentage of carboxy containing monomer units in terms of total monomer units in the polymer is <30%, preferably <20%. The amount of carboxy groups in the polymer is effective, upon the neutralization with alkali, to impart a certain degree of dispersability and stability to the polymer in the aqueous solution.

Carboxylic acid containing polymers can be neutralized by alkaline solutions containing lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, amine, etc. While neutralized carboxylic acid groups are required to impart substantial water solubility to the polymer, a minimum amount of such groups is preferred to retain the hydrophobicity of polymers for their intended application. Hydrocarbon monomer units in these anionic polymers can be partially unsaturated but preferably contain no unsaturation in the final polymer structure. Examples of suitable hydrocarbon monomers for the construction of anionic polymers for use in the present invention are ethylene, propylene, butadiene, hexadiene, isobutene, isoprene, 4-methyl-pentene, styrene, xylylene, methyl styrene, etc. The amount of carboxy containing polymer used in practicing the invention should be greater than 1%, preferably >5%, more preferably >10%. The emulsions used in preparing the compositions of the invention usually contain from about 10 to about 40 weight percent anionic polymer and sufficient emulsion is used to obtain from about 10 to about 75 and preferably from about 20 to about 50 weight percent of polymer in the dry composite composition of the invention. Wax used in practicing the invention is hydrophobic wax that should be a solid at room temperature (70OF) . These waxes may be paraffin wax, e.g. in the form of mixed hydrocarbon waxes containing a high proportion of C₁₆ - C₄₀ alkanes, macrocyrstalline, microcrystalline paraffin wax produced by a solvent dewaxing process, or slack wax produced by a sweating process. The wax is usually a saturated hydrocarbon wax but may be a partially or completely halogenated C₁₆ - C₄₂, e.g. with fluorine, Paraffin wax suitable to be used in the present invention may be represented, for example, by Paracol wax emulsion from Hercules. The waxes are emulsified with the aid of cationic, anionic, or nonionic surfactants to form stable emulsions. Preferably anionic or nonionic surfactant is used in the emulsification. The wax emulsions used to prepare the composite composition may contain from about 10 to about 40 weight percent wax. Sufficient wax emulsion is used to obtain a wax concentration in the finished dried cellulose composite greater than 1%, preferably greater than 5%, and more preferably greater than 10%, based on the total dry weight of the composition.

A fluoroalkyl acrylate polymer may optionally be included in the mixture. "Fluoroalkyl acrylate polymer" as used herein means a fluorinated acrylate polymer preferably containing from about 25 to about 40 weight percent flurine. Such acrylate polymers can be formed by means known to those skilled in the art, e.g. heating of a fluorinated ester of acrylic acid in the presence of an initiator such as a peroxide. Copolymers can also be formed by heating the fluorinated acrylic acid ester with other compounds reactive with acrylic unsaturation, e.g. other acrylic acid esters. A particularly suitable fluorinated acrylic acid ester is 2-propenoic acid, 2{ { (heptadecafluoro-octyl) sulfonyl}methyl amino} ethyl ester. Suitable comonomers to make fluoroalkyl acrylate copolymers are 2-propenoic acid, 2 -methyl-oxiranyl methyl ester; and 2-propenoic acid, 2-ethoxyethyl ester.

A preferred fluoroalkyl acrylate copolymer contains 35 to 40 weight percent fluorine and is made by the copolymerization of ethanaminium, N,N,N-trimethyl-2- { (2- methyl-l-oxo-2-propenyl) -oxy}- , chloride; 2-propenoic acid, 2-methyl-, oxiranylmethyl ester; 2-propenoic acid, 2- ethoxyethyl ester; and 2-propenoic acid, 2{{ (heptadecafluoro-octyl) sulfonyl }methyl amino}ethyl ester. This preferred fluoroalkyl acrylate copolymer has been assigned CAS Reg. No. 92265-81-1.

The quantity of fluropolymer, e.g. fluoroalkyl- acrylate polymer, when included, may be any suitable amount, but usually from 0.1 to 15 percent and preferably 0.1 to 5 percent by weight of mixture.

For the purpose of present invention, the term "surface tension" can be considered to have reference to a single factor consisting of such variables as intermolecular, or secondary bonding forces, such as permanent dipole forces, induced dipole forces, dispersion or non-polar Van der Waals forces, hydrogen bonding forces, and ionic bonding forces. Surface tension is theorized and experimentally confirmed to influence surface wetting and non-wetting effects and thus has an effect upon adhesive characteristics. It is an experimental fact that wetting is the first requirement for an adhesion to occur between two surfaces.

Surface tension is theorized to consist of two types of interactions, one is polar interaction and another one is non-polar interaction. The fraction of polar interaction within the total interaction is defined as "polarity" . Many polymer solids have been experimentally found to have a good correlation between the polarity determined by contact angle measurement and their chemical structures. For example, polyethylene has a polarity of 0-3% because the majority of the polymer structure comprises alkyl chains and does not contain any significant amount of polar functional groups such as ether, hydroxyl, sulfone, imine, halogen, carbonate, amide, or carboxylic acid. In contrast, polyamide contains amide functional groups and has a polarity of 20-40%, depending on the fraction of other non-polar structure in the polymers . Due to the good correlation between the polarity of a material surface and the chemical structure of the material, polarity is considered a characteristic parameter of a particular surface and has influence on the wetting and non-wetting behaviour of the surface.

Interfacial tension between two surfaces is another characteristic parameter which measures the compatability between two surfaces . A zero interfacial tension indicates a complete wetting between two surfaces, whereas a positive interfacial tension indicates partial wetting.

Another characteristic parameter is the spreading coefficient which measures how easy a surface can be wetted by a substance, a positive spreading coefficient indicates good wetting and a negative value indicates poor wetting.

The fundamental concept of wetting is Young's equation γ_LVcosθ=γ_sv-γ_SL, which describes the contact angle θ of a liquid drop on a solid is influenced by the surface tension of liquid, γ_LV, surface tension of solid, γ_sv, and the interfacial tension between the liquid and the solid, y_SL. The work of adhesion, W_a is defined as W_a=y_I+y₂-y_I2, which describes the work required to separate two surfaces as being equal to the difference between the sum of individual surface tensions, γ₁ t-γ₂ι and the interfacial tension between two surfaces, γ₁₂. The combination of these two equations gives the work of adhesion between a liquid and a solid, which can be experimentally obtained from the contact angle measurement. The combined equation is VS_a= y_LV(l+cosθ) , which can be used to experimentally determine the surface tension and polarity of the surface of a particular solid material when combined with the fractional theory of surface tension. In the following examples, illustrating the present invention, surface properties including surface tension, polarity, interfacial tension between cellulose composite and polypeptide, work of adhesion between cellulose composite and polypeptide, and polypeptide spreading coefficient are measured and calculated from contact angle measurements by using a series of organic liquids of varying polarities. The physical characterization method used here is not intended as an absolute measurement of surface properties, but instead it is used consistently for all surfaces to demonstrate the difference between different surfaces for the purpose of comparison.

In addition to forming a cellulose composite film, the composition of the current invention can also be used to produce hydrophobic fibers which can then be used to increase the compatability between the cellulose fiber and polyethylene in the application of increasing the stiffness of polyethylene composite. These hydrophobic fibres can also be used in the manu acturing of papers and textiles to produce articles possessing at least some moisture-barrier characteristics. The composite materials of the present invention may be used for the formation of cellulose containing hydrophobic products such as films, coatings, laminates, fibres, sheets, fiber-reinforced cellulose casing, cellulose casings, etc.

The following examples are provided to illustrate preferred embodiments of the invention and are not intended to restrict the scope thereof. Unless otherwise indicated, all percentages are expressed as weight percentages . Example 1

A 10% aqueous dispersion of sodium salt of poly (ethylene-acrylic acid), {PEA}, 80/20 ethylene/acrylic acid was mixed with 10% of paraffin wax emulsion at 4:1 ratio. 23.8 gm of 10% emulsion mixture prepared as described were then mixed with 29.5 grams of xanthate viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was spread on a cellulose fiber paper web with a Vz" diameter #90 wire-wound rod and subsequently coagulated and regenerated in a conventional sulfuric acid/sodium sulfate bath as previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 15 minutes at 103°C The surface tension was measured to be 35 dyne/cm with a polypeptide spreading coefficient of -31 dyne/cm, a polarity of 0%, and a polypeptide-composite interfacial tension of 21 dyne/cm. This sample was designated as sample A.

Example 2

A 10% aqueous dispersion of sodium salt of poly (ethylene-acrylic acid), as previously described, was mixed with 10% of wax emulsion at 3:1 ratio. 20.4 grams of the resulting 20% emulsion mixture were then mixed with 37.9 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a fibrous cellulose paper web with a V∑" diameter #90 wire-wound rod and subsequently coagulated and regenerated in the conventional acid/salt bath as previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 20 minutes at 104°c. The surface tension was measured to be 34 dyne/cm with a polypeptide spreading coefficient of -33 dyne/cm, a polarity of 1%, and a polypeptide-composite interfacial tension of 20 dyne/cm. This sample is designated as sample B.

Example 3

A 10% aqueous dispersion of sodium salt of poly (ethylene-acrylic acid), as previously described, was mixed with 10% of wax emulsion at 2:1 ratio. 13.5 grams of the resulting 10% emulsion mixture were then mixed with 39.3 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a fibrous cellulose paper web with a V2" diameter #90 wire-wound rod and subsequently coagulated and regenerated in a conventional acid/salt bath as previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 20 minutes at 102°C The surface tension was measured to be 35 dyne/cm with a polypeptide spreading coefficient of -30 dyne/cm, a polarity of 3%, and a polypeptide-composite interfacial tension of 18 dyne/cm. This sample is designated as sample C.

Example 4

A 9.9% aqueous dispersion of sodium salt of poly (ethylene-acrylic acid), as previously described, was mixed with 9.3% of wax emulsion at 1:1 ratio. 8.5 grams of the resulting 9.6% emulsion mixture were then mixed with 43.0 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a fibrous cellulose paper web with a Vz" diameter #90 wire-wound rod and subsequently coagulated and regenerated in a conventional acid/salt bath as previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 20 minutes at 100°C. The surface tension was measured to be 31 dyne/cm with a polypeptide spreading coefficient of -28 dyne/cm, a polarity of 9%, and a polypeptide-composite interfacial tension of 13 dyne/cm. This sample is designated as sample D.

Example 5

This example is for a blend of cellulose and wax only without poly (ethylene-acrylic acid). The surface properties were measured and compared with that of the foregoing examples illustrating the present invention. 14.6 grams 9.9% wax emulsion were mixed with 27.1 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a fibrous cellulose paper web with a V-." diameter #90 wire-wound rod and subsequently coagulated and regenerated in a conventional sulfuric acid/sodium sulfate bath as previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 15 minutes at 100°C. This sample is designated as sample E.

Example 6

This example is for a blend of cellulose and wax without poly (ethylene-acrylic acid) . The surface properties were measured and compared with that of the current invention. 10.1 grams 9.6% wax emulsion were mixed with 28.3 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a cellulose paper web with a Vfe" diameter #90 wire-wound rod and subsequently coagulated and regenerated in a conventional acid/salt bath as previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 15 minutes at 100°C. This sample is designated as sample F.

Example 7

This example is for a blend of cellulose and wax only without poly (ethylene-acrylic acid). The surface properties were measured and compared with that of the current invention. 6.5 grams of 10% wax emulsion were mixed with 30.9 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a cellulose paper web with a Vz" diameter #90 wire-wound rod and subsequently coagulated and regenerated in the conventional acid/salt bath previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 20 minutes at 102°C. This sample is designated as sample G.

Example 8

This example is for a blend of cellulose and poly (ethylene-acrylic acid) without wax. The surface properties were measured and compared with that of the current invention. 17.8 grams of 10% aqueous emulsion of poly (ethylene-acrylic acid) were mixed with 33.4 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a cellulose paper web with a V2¹' diameter #90 wire-wound rod and subsequently coagulated and regenerated in the conventional acid/salt bath as previously described.

The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 35 minutes at 100°C. This sample is designated as sample H.

Example 9

This is another example for a blend of cellulose and poly (ethylene-acrylic acid) without wax. The surface properties are measured and compared with that of the current invention. 12.7 grams of 10% aqueous emulsion of poly (ethylene-acrylic acid) are mixed with 36.9 grams of viscose containing of 8% of cellulose. After homogenization, the viscose containing the emulsion mixture was cast on a cellulose paper web with a V2" diameter #90 wire-wound rod and subsequently coagulated and regenerated in the conventional acid/salt bath previously described. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 20 minutes at 100°c. This sample is designated as sample I.

Example 10

This is a further example of a blend of cellulose and poly (ethylene-acrylic acid) without wax. The surface properties are measured and compared with that of the current invention. 10.4 grams of 10% aqueous emulsion of poly (ethylene-acrylic acid) are mixed with 52.1 grams of viscose containing about 8% of cellulose. After homogenization, the viscose containing the emulsion mixture is cast on the cellulose paper web with a V2" diameter #90 wire-wound rod and subsequently coagulated and regenerated in the previously described conventional acid/salt bath. The resultant regenerated cellulose fiber reinforced composite was then dried in an oven for 30 minutes at 100°c. This sample is designated as sample J.

Example 11 Comparison of Surface Properties

The surface properties including surface tension, polarity, interfacial tension, work of adhesion, and protein spreading coefficient of the foregoing samples were measured and calculated from the contact angle data obtained by using a series of solvents with varying surface tension and polarity. The contact angle measurements were carried out by using a Contact Angle Viewer manufactured by Kayeness, Inc. in Honey Brook, PA. The work of adhesion, interfacial tension, and spreading coefficient are calculated from the surface tension and polarity of composite surface and polypeptide (mixed poly ( -methyl-L- glutamate) β sheet) surface. The polypeptide surface had a surface tension of 42 dyne/cm and a polarity of 36%. The polypeptide was used as a standard to evaluate the adhesion on different surfaces. The physical characterization method used here is not intended as an absolute measurement of surface properties, but instead it is used consistently for all surfaces to demonstrate the difference between different surfaces for the purpose of comparison. The surface properties of Examples 1 through 10 are tabulated in Table 1 for easy comparison.

It is apparent from table 1 that the current invention of cellulose composite produce surface properties similar to that of polyethylene. It also shows that the composition of the current invention gives a much lower surface tension than using poly (ethylene-acrylic acid) , [PEA] or paraffin alone in the cellulose composite at the same weight fraction.

Example 12 Comparison of Surface Properties

The method of measuring the surface properties is the same in this example as that described in Example 11. The current example gives the surface properties of an alkyl ketene dimer coated cellulose surface, which has been known to give minimum adhesion to the hydrophilic surface such as sausage meat surface (for example, U.S. Patent 3,158,492 and U.S. Patent 3,106,471). The surface properties including surface tension, polarity, interfacial tension, work of adhesion, and polypeptide spreading coefficient are listed in Table II.

Comparing Table II and Table I, one can easily see that the current invention gives a surface that is incompatible with hydrophilic substance such as sausage meat surfaces.

Example 13

0.25 kg of 32% Perfluoroalkyl acrylate copolymer emulsion (CAS 92265-81-1), 5.18 kg of 32% paraffin wax (M.P. = 1270F) emulsion, 6.8 kg of 17.9% poly (ethylene- acrylic acid) (PEA) emulsion, and 16.5 kg of 7.7% cellulose solution were mixed together. The mixture was added onto the inside of a paper tube impregnated with cellulose solution from the outside, coagulated, regenerated, washed, and dried so that the final dry weight of the inside film was 14 gm/m². The dry film consisted of about 2% Perfluoroalkyl acrylate copolymer, 39% paraffin wax, 29%

PEA, and 30% cellulose. The tube was then stuffed with brine injected, salted, de-boned and de-fatted pork lion.

The stuffed product was dried, smoked, cooked, cooled, and frozen. After freezing, the tube was peeled. The casing could be easily peeled without adhesion spots. The surface properties were measured, indicating a polarity equal to 0.4% and surface tension equal to 39 dyne/cm.

Example 14

0.25 kg of 32% Perfluoroalkyl acrylate copolymer emulsion (CAS 92265-81-1), 3.83 kg of 32% paraffin wax (M.P. = 14loF) emulsion, 8.54 kg of 20.4% poly (ethylene- acrylic acid) (PEA) emulsion, and 17 kg of 7.7% cellulose solution were mixed together. The mixture was added onto the inside of a paper tube impregnated with cellulose solution from the outside, coagulated, regenerated, washed, and dried so that the final dry weight of the inside film was 14 gm/m². The dry film consisted of about 2% Perfluoroalkyl acrylate copolymer, 28% paraffin wax, 40% PEA, and 30% cellulose. The tube was then stuffed with de-fatted pork loin, as described in Example 13. The stuffed product was dried, smoked, cooked, cooled, and frozen. After freezing, the tube was peeled. The casing could be easily peeled without adhesion spots. The surface properties were measured, indicating a polarity equal to 0.4% and surface tension equal to 34 dyne/cm.

Example 15

26.79 kg of 32% paraffin wax (M.P. = 141°F) emulsion, 55.94 kg of 20.4% poly (ethylene-acrylic acid) (PEA) emulsion were mixed together. 10 kg of the above mixture and 13.46 kg of 7.7% cellulose solution were mixed, and added onto the inside of a paper tube impregnated with cellulose solution from the outside, coagulated, regenerated, washed, and dried so that the final dry weight of the inside film was 8 gm/m². The dry film consisted of about 30% paraffin wax, 40% PEA, and 30% cellulose. The tube was then stuffed with meat to make pepperoni dry sausage. After cooking and drying, the tube is peeled. The casing could be easily peeled without adhesion spots.

Example 16

26.79 kg of 32% paraffin wax (M.P. = 141°F) emulsion, 55.94 kg of 20.4% poly (ethylene-acrylic acid) (PEA) emulsion were mixed together. 10 kg of the above mixture and 11.61 kg of 7.7% cellulose solution were mixed, and added onto the inside of a paper tube impregnated with cellulose solution from the outside, coagulated, regenerated, washed, and dried so that the final dry weight of the inside film was 14.8 gm/m². The dry film consisted of about 31% paraffin wax, 42% PEA, and 27% cellulose. The tube was then stuffed with meat to make pepperoni dry sausage. After cooking and drying, the tube was peeled. The casing could be easily peeled without adhesion spots. The surface properties were measured, indicating a polarity equal to 2.8% and surface tension equal to 34 dyne/cm.

Example 17

26.79 kg of 32% paraffin wax (M.P. = 141°F) emulsion, 55.94 kg of 20.4% poly (ethylene-acrylic acid) (PEA) emulsion were mixed together. 10 kg of the above mixture and 11.61 kg of 7.7% cellulose solution were mixed, and added onto the inside of a paper tube impregnated with cellulose solution from the outside, coagulated, regenerated, washed, and dried so that the final dry weight of the inside film was 14.8 gm/m². The dry film consisted of about 31% paraffin wax, 42% PEA, and 27% cellulose. The tube was then stuffed with pork shoulder meat and cooked. After cooking the tube was peeled. The casing could be easily peeled without adhesion spots. The surface properties were measured, indicating a polarity equal to 0.3% and surface tension equal to 34 dyne/cm.

Example 18

26.79 kg of 32% paraffin wax (M.P. = 141op) emulsion,

55.94 kg of 20.4% poly (ethylene-acrylic acid) (PEA) emulsion were mixed together. 10 kg of the above mixture and 13.46 kg of 7.7% cellulose solution were mixed, and added onto the inside of a paper tube impregnated with cellulose solution from the outside, coagulated, regenerated, washed, and dried so that the final dry weight of the inside film was 13.3 gm/m². The dry film consisted of about 30% paraffin wax, 40% PEA, and 30% cellulose. The tube was then stuffed with salted, lean pork, dried, smoked, and blast-frozen to make dry pork filet. After cooking, the tube was peeled. The casing could be easily peeled without adhesion spots.

The same casing was also stuffed with salted, lean pork back meat, smoked, cooked, and cooled to ~2°C. The casing was peeled the next day. The casing could be peeled easily without any adhesion spots.

The same casing was also stuffed with lean skinned pork bellies, which had been salted and rolled through spices and gelatin. The product was cooked, and then cooled to ~2°C . The casing was peeled the next day. The casing could again be peeled easily without any adhesion spots .

Example 19

3.54 kg of 32% paraffin wax (M.P. = 141OF) emulsion,

12.84 kg of 22.1% poly (ethylene-acrylic acid) (PEA) emulsion were mixed together. 10 kg of the above mixture and 13.49 kg of 7.7% cellulose solution were mixed, and were added onto the inside of a paper tube impregnated with cellulose solution from the outside The whole tube was then coagulated, regenerated, washed, and dried so that the final dry weight of the inside film was 3 gm/m². The dry film consisted of about 20% paraffin wax, 50% PEA, and 30% cellulose. The casing was then impregnated with liquid smoke solution. The tube was then stuffed with ham-type meat, cooked, and cooked to make ham product. After cooling the case could be easily peeled without adhesion spots .

Having thus described the invention, numerous changes and modifications thereof will be readily apparent to those having ordinary skill in the art without departing from the spirit or scope of the invention. For example, the compositions of the present invention also can contain fillers, colorants, stabilizers, and the like.

Table I

Table II

Claims

Claims :

A cellulose composite composition, comprising hydrophobic wax, an aqueous dispersible carboxy containing anionic polymer, and cellulose formed by the coagulation, regeneration and drying of a mixture comprising paraffin wax emulsion, carboxy containing anionic polymer emulsion, and viscose, said composite having a hydrophobic surface with reduced adhesion to hydrophilic surfaces when compared with regenerated cellulose alone.

The cellulose composite composition of Claim 1, wherein the mixture further comprises a fluoralkyl-acrylate polymer.

3. The composition according to Claim 1, comprising from about 1 to about 60 weight percent of aqueous dispersible carboxy containing polymer.

4. The composition according to Claim 1, where the aqueous dispersible carboxyl containing polymer comprises polymerized monomer units, less than 30 numerical percent of which contain carboxy groups .

5. The composition according to Claim 1, where the aqueous dispersible anionic polymer comprises at least 70% by weight of hydrocarbon monomer units in addition to the carboxy containing monomer units .

6. The composition of Claim 4 wherein aqueous dispersible anionic polymer is selected from the group consisting of poly (ethylene-acrylic acid), poly (propylene-acrylic acid) , poly (ethylene- propylene-acrylic acid) copolymers, and mixtures thereof .

7. The composition according to Claim 1, where the anionic polymer emulsion comprises carboxy containing groups that are at least partially neutralized carboxylic acid functional groups.

8. The composition according to Claim 7, where the carboxy containing groups are carboxylic acid functional groups in the aqueous dispersible anionic polymer that are at least or partially neutralized by alkaline solution to form carboxylic acid salt.

9. The composition of Claim 8 wherein the alkaline solution for neutralization is selected from the group consisting of solutions of lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide, and mixtures thereof.

10. The composition according to Claim 1, comprising greater than 1% of paraffin wax.

11. The composition of Claim 1 comprising from about 10 to about 50 weight percent anionic polymer, from about 5 to about 40 weight percent paraffin wax and from about 25 to about 85 weight percent cellulose .

12. The composition of Claim 2, wherein the mixture further comprises from about 0.1 to about 5 weight percent of perfluoro-acrylate polymer.

13. The composition according to Claim 1, where the paraffin wax has a melting point greater than

14. The composition according to Claim 1, where the paraffin wax emulsions comprise a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants and mixtures thereof .

15. A shaped material comprising the composition of Claim 1.

16. A shaped material comprising the composition of Claim 2.

17. The shaped material of Claim 15 comprising a coating.

18. The shaped material of Claim 15 comprising a laminate.

19. The shaped material of Claim 15 comprising a fiber.

20. The shaped material of Claim 15 comprising a food casing.

21. The food casing of Claim 20 comprising a fiber reinforcement .

22. The shaped material of Claim 15 comprising a sheet material.

23. The shaped material of Claim 15 comprising a film.

24. A method for making a composite composition of Claim 1 which comprises: a) mixing an anionic polymer emulsion and a wax emulsion into viscose to obtain a solution from which cellulose may be precipitated; b) precipitating the cellulose; and c) removing residual water from the precipitated cellulose by drying.

25. The method of Claim 24 wherein the cellulose is precipitated from a xanthate viscose solution by coagulation in an acid-salt bath followed by regeneration.

26. The method of Claim 24 wherein the composite composition is in the form of a tubular food casing film.

27. The method of Claim 24 wherein fluoroalkyl- acrylate emulsion is also mixed with the anionic polymer and wax emulsions.

28. The method of Claim 24 wherein the wax emulsion is a paraffin wax emulsion.