MXPA99010367A - Polymers that are used as debarr coatings - Google Patents

Abstract

The use of polymers as barrier coatings for paper applications is disclosed. The polymers provide water absorption and low water vapor transmission rates, as well as the ability to be reduced back to the country.

Description

Polymers Used as Barrier Coaters The present invention relates to the use of polymers in the form of barrier coatings in paper applications. Barrier coating means a layer or coating that prevents the penetration of oil, water or moisture through paper products. Barrier coatings are typically applied on cardboard, corrugated cardboard, Kraft paper and ream wrap. Containers made of paper can be used to transport fruits, meats, vegetables, sweets and the like. There are several problems associated with the use of these containers, a problem being that the containers may get wet when the materials transported in the container are wet or when the container is exposed to rain or a humid environment. The paper with which the containers are made is usually delicate, and stains as a result of being exposed to water. This can lead to the container breaking and opening, and the content of the container to come out. To avoid this problem, containers are usually covered with a material such as wax, to prevent water from contacting the paper.

A problem with containers covered with wax is that although wax is effective in preventing water and oil from contacting paper, wax is usually applied in the form of a thick coating. Thick means that a dry coating has from 55 microns to 125 microns. The thick coating adds significant weight to the container. In fact, the wax can count from 20% to 40% by weight of the covered container. Therefore, it is desired to provide a barrier coating that is more efficient than wax so that a thinner coating can be applied without sacrificing the properties of the barrier coating. Both for economic reasons and for the conservation of natural resources, it is convenient to recycle the containers used to transport fruits, meats, vegetables, sweets and the like. However, a second problem with containers covered with wax is that the wax coating makes it difficult to recycle the paper from which the container is made. The wax adheres to the fibers of the paper, making it difficult to reduce the fibers to paste. There is a continuing need for a barrier coating that is more efficient than wax, and easier to remove from paper fibers, than wax.

Thus, it has been found that the use of a polymer as a barrier coating allows the reduction of the amount of coating used, without sacrificing the barrier coating properties, while improving the ability to recycle the coated paper. U.S. Patent No. 5,521,266 discloses a method for forming polymers from hydrophobic monomers. The disclosed method utilizes macromolecular organic compounds that have a hydrophobic cavity to complex monomers that have low water solubility. This allows the formation of polymers from monomers of low water solubility by emulsion polymerization. Monomers suitable for use in the method in which polymers are formed include lauryl methacrylate and stearyl methacrylate. The patent does not disclose the utility of polymers as barrier coatings. Patent application WO 94/26513 discloses stacks of recyclable paper covered with an emulsion containing an acrylic styrene copolymer and a wax. The copolymers tested are limited to the lower alkyl acrylic styrene copolymers. Despite these disclosures, there is a continuing need for a barrier coating that is more efficient than wax, and easier to remove from paper fibers than wax. As used in this description, the term (meth) acrylic means acrylic or methacrylic, and (meth) acrylate acrylate or methacrylate. The present invention provides a method for modifying paper substrates, comprising: applying a polymer to the paper substrate, wherein the polymer contains as polymerized units: a) from 1 to 100 parts by weight of at least one C1 to C0 alkyl ester of (meth) acrylic acid, b) 0 to 99 parts by weight of at least one ethylenically unsaturated monomer, and e) 0 to 15 parts by weight of at least one monomer containing ethylenically unsaturated acid or its salts. The polymer can be applied as it is to a paper substrate, to modify the paper substrate. The modification of the paper substrate results in good recycling properties and barrier coating. Alternatively, the polymer can be used as an additive to improve the recycling and barrier coating properties of latexes such as, but not limited to, butyl acrylate / methyl methacrylate, butyl acrylate / styrene, styrene / butadiene and vinyl acetate latex.

The present invention also provides an article that includes a paper substrate coated with the polymer described above. Also within the scope of the present invention is an article that includes a paper substrate coated with the mixture described above. The polymer used in this invention can be prepared by means of a single-phase or multi-phase process. The process can be an emulsion polymerization. See US patent no. 5,521,266 for a detailed description of the emulsion polymerization processes. The process can also be a solution polymerization followed by an emulsion. You have to see the US patent no. 5,539,021 for the detailed description of a solution polymerization followed by a mini-emulsion polymerization or microemulsion polymerizations. The emulsion polymerization process of US Pat. 5,521,266. The morphology of the polymer used in this invention can be designed to improve certain properties of the polymer. For example, the polymer can be made with a core / shell morphology, wherein the core polymer is designed to have a lower glass transition temperature than the polymer that creates the shell. This type of morphology can improve the barrier properties, as well as the blocking properties. Alternatively, the polymer that forms the core can be designed to have a glass transition temperature greater than the polymer that forms the shell. In that case, the core can act as a filler and the cover can link together stronger cores, to aid in film formation. The core / shell polymers can be prepared by methods well known in the art. In the process used to prepare samples in this application, a first phase was prepared by adding an emulsion of monomer and sodium persulfate to a solution containing methyl-β-cyclodextrin ("CD"), deionized water and surfactant. The first phase was reacted at 85 ° C. A second phase was prepared by preparing a second monomer emulsion, and feeding the second monomer emulsion and a sodium persulfate solution to the first reacted phase. The second phase was reacted at 85 ° C. The polymer used in this invention is a composition containing as polymerized units from 1 to 100 parts by weight, preferably from 5 to 95 parts by weight, and better, from 10 to 90 parts by weight of at least one C 12 alkyl ester to C40 of (meth) acrylic acid. It is further preferred that the polymer used in this invention contain as polymerized units from 20 to 80 parts by weight, preferably 30 to 70 parts by weight, and better, from 40 to 60 parts by weight of at least one C 12 alkyl ester C40 of (meth) acrylic acid. It is preferable that the alkyl ester of (meth) acrylic acid is a C12 to C30 alkyl ester of (meth) acrylic acid. It's better than the acid alkyl ester (meth) acrylic is an alkyl ester Ci 2 to C 8 acid (met) acrylic. Suitable alkyl (meth) acrylic acid esters include, but are not limited to, (meth) lauryl acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate and Eicosyl (meth) acrylate. Charitable properties can be obtained by using more than one Ci2 to C40 alkyl ester of (meth) acrylic acid. The polymer used in this invention may also contain as polymerized units from 0 to 99 parts by weight, preferably from 4 to 94 parts by weight, and better, from 9 to 89 parts by weight of at least one ethylenically unsaturated monomer. It is better that the polymer used in this invention contain - as polymerized units of 18 to 80 parts by weight, preferably 28 to 70 parts by weight, and better, of 38 to 60 parts by weight of at least one ethylenically unsaturated monomer . Ethylenically unsaturated monomers suitable for use in the preparation of the polymer compositions of this invention include, but are not limited to, (meth) acrylic ester monomers that include methyl acrylate, ethyl acrylate, butyl acrylate, acrylate of 2-ethylhexyl, decyl acrylate, methyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate and hydroxypropyl acrylate; Acrylamide or substituted acrylamides; styrene or substituted styrene; vinyl acetate or other vinyl esters; vinyl monomers such as vinyl chloride, vinylidene chloride, N-vinyl pyrolidone; and acrylonitrile or methacrylonitrile. Preferred are butyl acrylate, methyl methacrylate and styrene. The polymer used in this invention can also contain as polymerized units from 0 to 15 parts by weight, preferably from 1 to 10 parts by weight, and better, from 1 to 5 parts by weight of monomer containing ethylenically unsaturated acid or its salts . Suitable monomers containing ethylenically unsaturated acid include, but are not limited to, acrylic acid, methacrylic acid, crotonic acid, phosphoethyl methacrylate, 2-acrylamido-2-methyl-l-propanesulfonic acid, sodium vinyl sulfonate, itaconic acid , fumaric acid, maleic acid, monomethyl itaconate, monomethyl fumarate, monobutyl fumarate and maleic anhydride. Acrylic acid and methacrylic acid are preferred. Methacrylic acid is still better. The polymer used in this invention may also contain as polymerized units from 0 to 25 parts by weight, preferably from 0 to 15 parts by weight, and better, from 0 to 10 parts by weight of an ethylenically unsaturated monomer of (meth) acrylate. fluorinated, such as Zonyl ™ products (trademark of DuPont Chemical Company). The polymer used in this invention can also contain as polymerized units from 0 to 25 parts by weight, preferably from 0 to 15 parts by weight, and better, from 0 to 10 parts by weight of an ethylenically unsaturated monomer containing silicone, such as vinyl-trimethoxy-silane and methacryloxy-propyltrimethoxysilane. The polymer used in this invention can also contain as polymerized units from 0 to 80 parts by weight, preferably from 0 to 50 parts by weight, and better, from 1 to 15 parts by weight of a monomer selected from the styrene of alkyl-alpha C3-C2o alkyl and styrene, C6-C2O alkyl dialkyl itaconate? vinyl esters C10-C2o of carboxylic acids, methacrylamide and acrylamide of N-C8-C2alkyl-hydroxymethylacrylate C?-C2o alkyl or 2,2'- (oxydimethylene) C8-C2o dialkyl diacrylate / 2,2'- ( C 8 -C 20 dialkyldimethylene) alkyl methacrylate, C 8 -C 2 N-alkylacrylamide and C 10 -C 20 alkyl vinyl ether. The compositions of this invention may also contain as polymerized units from 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and better, from 0.1 to 3 parts by weight, based on the weight of polymer of a binder selected from a binder and a binder monomer. By "binder" is meant a compound having at least two reactive groups which will react with acid groups found in the monomers of the compositions of this invention. The binding agents useful in this invention include a polyaziridine, polyisocyanate, polycarbodiimide, polyamine and a polyvalent metal. The binder is optional, and may be added after the polymerization is complete.

The binder monomers are binders which are incorporated with the monomers of the compositions of this invention during the polymerization. The binder monomers useful in this invention include acetoacetate functional monomers such as acetoacetoxyethyl acrylate, allyl acetoacetate, acetoacetoxybutyl methacrylate, and 2,3-di (acetoacetoxy) propyl methacrylate; divinyl benzene, (meth) acryloyl polyesters of polyhydroxy compounds, divinyl esters of polycarboxylic acids, diallyl esters of polycarboxylic acids, diallyl dimethyl ammonium chloride, triallyl terephthalate, methylene bis-acrylamide, diallyl maleate, diallyl fumarate, hexamethylene bis-maleamide, triallyl phosphate, trivinyl trimellitate, divinyl adipate, glyceryl trimethacrylate, diallyl succinate, dinivil-ether, divinyl ethers of ethylene glycol or diethylene glycol diacrylate, methacrylates or polyethylene glycol diacrylates , 1,6-hexanediol diacrylate, pentaerythritol tetraacrylate and triacrylate, neopentyl glycol diacrylate, cyclopentadiene diacrylate, butylene glycol diacrylates or dimethacrylates, trimethylolpropane di (methacrylates), (meth) acrylamide, n-methylol (meth) acrylamide , mixtures of these, and the like. Preferred are (meth) acrylamide, (meth) acrylamide of n-methylol and mixtures thereof. The amount of binder used is chosen in such a way that the binder does not interfere with the formation of the film. The chain transfer agents can be used to control the molecular weight of the polymer composition. Suitable chain transfer agents include mercaptans, such as dodecyl mercaptan. The chain transfer agent can be used from 0.1% to 10%, based on the total weight of the polymer composition.

The fillers can be added to the polymers that are to be used in this invention. Fillers can improve the properties of the barrier coating, such as water resistance, oil resistance and blocking resistance of the polymer. Blocking means the stickiness of the coated surface. Blocking is not convenient since the covered paper is often rolled up, and blocking makes it difficult for the coated paper to unwind. Suitable fillers include talc (magnesium silicate), calcium carbonate, titanium dioxide, clay (aluminum silicate) and plastic pigments such as polystyrene. The fillers can be mixed with the polymer to be used in this invention, at levels ranging from 10% to 150% by weight, based on the dry weight of the polymer. The polymer used in this invention is typically used to modify paper substrates when applying the polymer to a paper substrate. The paper substrate can be selected from paperboard, corrugated cardboard, Kraft paper, ream wrap and the like. The polymer can be applied to the paper substrate with a blade, knife, bar or roller, or by spraying, dipping, gravure, flexo or rubbing. Other coating methods known in the art may also be used. The polymer can be applied from lgr / m2 to 50gr / m2, preferably 5gr / m2 to 25gr / m2, to give a dry thickness from 1 micron to 50 microns, preferably 5 microns to 25 microns. Then the polymer is dried. The polymer can be dried under ambient conditions. Pressurized air can be used to aid in polymer drying. The pressurized air can be heated or the substrate covered with polymer can be placed in a heated oven. The temperature of the heat can vary from 35 ° C to 200 ° C. Other drying methods known in the art may also be used, such as the use of ultra violet or infrared rays, a steam heated cylinder or an electrically heated bar. The polymer can also be mixed with latex in barrier coating applications, to improve the properties of recycling and water impermeability. Any latex can be used. Suitable latexes include, but are not limited to,, but not limiting, butyl acrylate / methyl methacrylate, butyl acrylate / styrene, styrene / butadiene, and vinyl acetate latex. The amount of polymer mixed with the latex is typically from 1 to 50 parts by weight, preferably from 5 to 45 parts by weight, and better, from 10 to 40 parts by weight. The mixture is typically applied to the substrates as described above.

Through this patent application, the following abbreviations are used: MAL = lauryl methacrylate MAS = stearyl methacrylate Est = styrene MAM = methyl methacrylate AB = butyl acrylate AMA = methacrylic acid CD = methyl-β-cyclodextrin The following examples are intended to demonstrate the polymers that are useful in this invention, and the benefits obtained by using polymers in barrier coating applications. The examples should not be construed as limiting the scope of the invention.

Example 1 In phase 1, l, 400gr were introduced. of deionized water, anionic surfactant Triton® XN-45S (trademark of Union Carbide Chemical Company) and 28.6gr. of CD in a round bottom flask, with four liters capacity, with four necks, equipped with a mechanical stirrer, temperature control device, condenser, initiator and monomer feed lines, and a nitrogen inlet at room temperature. The contents were heated to 85 ° C while stirring under a nitrogen purge. Separately, a monomer emulsion was prepared.

In the reaction vessel, solutions of 0.35% by weight of sodium carbonate (based on the weight of the total monomer in phases 1 and 2) were introduced in 25gr. of deionized water, and 0.35% by weight of sodium persulfate (based on the weight of the total monomer in phases 1 and 2) in 30gr. of deionized water. The monomer emulsion was fed for a period of 20 minutes together with a 0.05% sodium persulfate initiator solution (based on the weight of the total monomer in phases 1 and 2) at 210 g. of deionized water. In phase 2, a second monomer emulsion was prepared using 625gr. deionized water, 7.8gr. of anionic surfactant Triton® XN-45S and monomers. Immediately after finishing the monomer emulsion feed of phase 1, the monomer emulsion of phase 2 was fed for a period of three hours together with the sodium persulfate initiator solution. The monomers of the first and second monomer emulsions were selected such that the polymers of Table 1 were obtained (based on the percentage by weight of monomer).

Table 1 MAS polymer MAL AB MAM Est AMA AN Zonyl 1 40 0 10 0 49 1 0 0 2 0 40 10 0 49 1 0 0 31 40 0 10 0 47 1 0 0 41 0 40 10 0 47 1 0 0 51 40 0 0 0 57 1 0 0 61 0 40 0 0 57 1 0 0 7 * 0 0 50 0 49 1 0 0 Shows MORE BAD AB MAM Est AMA AN Zonilo 8 * 1 0 0 50 0 47 1 0 0 92 40 0 0 0 57 1 0 0 10 93 0 0 5 0 2 0 0 11 4-6 47 0 5 0 2 0 0 121 40 0 5 42 0 1 10 0 131 0 40 10 0 47 1 0 0 131 40 0 5 42 0 1 0 10 15 * 2 0 0 50 0 47 1 0 0 161 30 0 0 5 61 2 0 0 171 0 30 0 5 61 2 0 0 184 0 40 0 0 58 1 0 0 193 0 40 0 0 58 1 0 0 201 ' 5 40 0 0 0 57 1 0 0 21?, 5 0 40 0 0 57 1 0 0 22 10 0 40 0 49 1 0 0 23 20 0 30 0 49 1 0 0 24 35 0 15 0 49 1 0 0 25 50 0 0 0 49 1 0 0 26 65 0 0 0 34 1 0 0 27 80 0 0 0 19 1 0 0 28 0 35 15 0 49 1 0 0 29 0 50 0 0 49 1 0 0 30 0 65 0 0 34 1 0 0 * the polymer that can typically be used as a barrier coating. 1 = contains 2% MOA (50% acrylamide / 50% n-methylol-acrylamide) 2 = contains 2% MAM (90% meacrylamide / 10% acrylamide) 3 = contains 1% MOA (50% of acrylamide / 50% n-methylol-acrylamide) 4 = contains 1% MAM (90% methacrylamide / 10% acrylamide) 5 = contains 0.2% n-dodecyl mercaptan. Standard tests, to establish the usefulness of polymer compositions in barrier coating applications, include the Cobb test with which the absorption of water in a polymer film is measured over a given time, the Transmission Index test of Water Vapor (ITVA) with which the amount of water vapor that penetrates a polymer film during a given time is measured, and a test of capacity of reduction back to paste that indicates whether the polymer film can be or not easily remove from the paper substrate, thus allowing the paper to be recycled. The polymers of Table 1 were tested by means of some of these tests, to determine their usefulness in barrier coating applications.

Test Cob. For most of the samples that were to be tested, a single wet coating was applied on the uncovered side (back side) of a bleached cardboard sheet of 224gr./m2, on a weight basis, using a bar rolled cable selected to give a dry coating weight of 10 to 15 gr./m2 when the coating was dried for 20 minutes at the drying temperature indicated in Table 2. For samples 22 to 30, a dry coating weight was applied from 15 to 19gr./m2 to reduce the possibility of holes, and the coating was dried at 150 ° C for one minute. The specimens were prepared at 25 ° C and 50% relative humidity, before the test. Coated samples were tested in accordance with SCAN P 12:64, water absorption of the paper (non-absorbent) and cardboard (Cobb test), testing only the coated side of the cardboard and using an exposure period of 30 minutes. minutes instead of 120 seconds. For examples 1 to 21, four specimens were tested per coating composition. For samples 22 to 30, two specimens were tested per coating composition. For samples 1 to 22, non-binding polymers were tested on films dried at 60 ° C, 90 ° C, 120 ° C and 150 ° C, and binder polymers were tested on films dried at 90 ° C, 120 ° C, 150 ° C and 180 ° C. The results of the tests are shown in Table 2. For the results of this test, the lower the number the better the development.

Table 2 Absorption of water for 30 minutes Cobb (crr./m2 Polymer 60 ° C 90 ° C 120 ° C 150 ° C 180 ° C None1 250 250 250 250 NP 1 4.4 3.7 3 3.5 NP 2 4.7 3.9 4.1 4.1 NP 3 NP 3.8 3.8 3.4 3.3 4 NP 6 4.1 4.1 3.7 5 NP 15.1 4.8 4.4 3.9 6 NP 43.7 11.5 5.3 3.4 7 * 76.8 33 21 20 NP 8 * NP 7.1 7.5 7.2 7.7 9 NP NP NP NP NP 10 NP NP NP NP NP 11 4.6 4.9 5.3 5.4 NP 12 NP 74.8 47.0 13.2 9.7 13 NP 7.1 7.5 7.2 7.7 14 NP 12.3 12.3 10.9 11.4 15 * NP 6.5 6.2 6.4 6.1 16 NP NP NP 87.9 83.0 17 NP NP NP 84.0 83.8 18 NP 36.5 10.4 4.6 3.5 19 NP 45.7 26.2 7.9 3.1 20 NP 4.3 3.7 3.1 3.9 21 NP 6.0 3.9 3.3 3.7 22 NP NP NP NP NP NP 23 PN NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP NP 2.3 NP 28 NP NP NP 2.1 NP 29 NP NP NP 1.1 NP 30 NP NP NP NP 1.9 NP * polymer that can be used as a barrier coating, 1 carried out for five minutes, and extrapolated to 30 minutes. = not tested. The previous results show that The non-binding polymers have very little water absorption at all drying temperatures tested. The binder polymers have a lower water absorption while increasing the drying temperature. It is understood that sometimes the coatings have cracks considered as holes. The presence of holes will allow the water to penetrate the coating, and therefore, increase both the water absorption and the ITVA. The inventors inspected the coatings made from the polymers 16 and 17 by means of a spotting technique where a quantity of dye was contacted with the covered copy for 5 minutes, and the holes counted. A lot of holes were discovered.

ITVA test. The ITVA test was carried out in accordance with a modified SCAN P 22:68. The conditions of the test were 25 ° C and 75% relative humidity. The non-binding polymers were tested on films dried at 60 ° C, 90 ° C, 120 ° C and 150 ° C. The binder polymers were tested on films dried at 90 ° C, 120 ° C, 150 ° C and 180 ° C. For samples 22 to 30, a dry coating weight of -15 to 19 gr./m2 was applied to reduce the possibility of holes. For samples 1 to 21, six specimens were tested per coating composition. For samples 22 to 30, two specimens were tested per coating composition. The results are shown in Table 3. For the results of this test, the lower the number the better the development.

Table 3 ITVA (g / m2 / 24 hours! Polymer 60 ° C 9Q ° C 120 ° C 150 ° C 180 ° C None 600 600 600 600 NP 1 180.3 152.6 145.7 140.3 NP 2 157.6 138.3 133.5 142.4 NP 3 NP 133.8 130.9 123.4 123.8 4 NP 145.9 133.6 131.6 122.7 5 NP 374.4 130.1 101.2 93.7 6 NP 348.8 142.5 120.5 108 7 * 505.8 393.7 353.7 346.8 NP 8 * NP 238.6 235.1 230.2 229.9 9 NP NP NP NP NP 10 568.3 550.2 543.3 502.5 NP 11 157.5 161.6 164.8 167.4 NP 12 NP 454.0 350.6 184.7 145.6 13 NP 238.6 235.1 230.2 229.9 14 NP 194.5 176.2 165.7 156.6 15 * NP 219.3 218.4 216.4 204.0 16 NP NP NP 536.8 545.7 17 NP NP NP 564.8 563.9 18 NP 434.3 284.1 135.6 104.3 19 NP 438.7 229.7 152.7 122.7 20 NP 98.5 95.7 93.1 106.1 21 NP 134.5 111.4 105.3 109.2 22 NP NP NP 114 NP 23 NP NP NP 101 NP 24 NP NP NP 78 PN 25 NP NP NP 64 NP 26 NP NP NP 74 NP 27 NP NP NP 88 NP 28 NP NP NP 90 NP 29 NP NP NP 64 NP 30 NP NP NP 73 NP * polymer that can typically be used as a barrier coating. The above results show that the non-binding polymers have very low ITVA at all drying temperatures tested, as compared to samples 7 and 8. The binder polymers have lower ITVAs while increasing the drying temperature. As discussed in the Cobb test results, the presence of holes will allow water to penetrate the coating, and therefore, increase both water absorption and ITVA. The inventors inspected the coatings made from the polymers 16 and 17 by means of a staining technique where an excess amount of dye was contacted with the covered specimen for 5 minutes, and the holes were counted. A large amount of needles was discovered.

The effect of coating weight on the absorption of water and ITVA. The effect of the coating weight on water absorption and ITVA was tested by coating cardboard with different coating weights of sample 5. The aliquots of sample 5 were applied to the cardboard, to provide coating weights of 8gr./m2 , 10gr./m2 and I5gr./m2. A sample of each coated paperboard was dried at 90 ° C, 120 ° C, 150 ° C and 180 ° C. Each sample was tested for 30 minutes Cobb and ITVA as described above. The results are shown in Table 4.

Table 4 Polymer 30 minutes Cobb ITVA (gr./m/24hours) (qr Vm2) 5 8ar / m2 90 ° C 75.4 587.1 120 ° C 76.4 548.6 150 ° C 66 511.7 180 ° C 77.2 550.6 5 10ar./m2 90 ° C 15.1 374.4 120 ° C 4.8 130.1 150 ° C 4.4 101.2 180 ° C 3.9 93.7 5 15ar./m2 90 ° C 4.2 101.1 120 ° C 3.3 79.3 150 ° C 3.3 77.5 180 ° C 2.5 77.8 none NP 599.6 The above results show that the polymers dramatically improve the ITVA when applied at a coating weight of 10gr./m2 or more. The polymers also dramatically improve water absorption resistance when applied at a coating weight of 10gr./m2 or more.

The effect of fillers on the absorption of water and ITVA. The effect of the fillers on water absorption and ITVA was tested by coating cardboard with talc mixtures and the polymers used in this invention. Talc was added on a weight basis based on the dry weight of the polymer. The samples were applied to the cardboard, and dried at 150 ° C for 20 seconds. Each sample was tested for 30 minutes Cobb and the ITVA as described above. The results are shown in Table 5.

Table 5 Polymer 30 minutes Cobb ITVA (ar./m2 / 24.) (Gr.m2) 5 4.4 101.2 5 + 20% talc 2.6 68.2 5 + 40% talc 3.3 46.6 6 5.3 120.5 6 + 20% talc 2.3 80.4 6 + 40% talc 2.7 53.5 12 13.2 184.7 12 + 20% talcum 9.6 139.6 12 + 40% talc 7.0 97.7 14 11.8 165.7 14 + 20% talc 8.3 135.5 14 + 40% talcum 7.4 103.9 The above results indicate that the addition of fillers to the polymers, used in this invention, improves both the water resistance and the water permeability of the barrier coating. An increase in the added amount of filler also improved the water resistance and water permeability of the barrier coating.

Ability to reduce back to pasta. The tests of pulp reduction capacity were carried out in a non-coated kraft type paper and a kraft-type paper coated with the sample 9. The average coating weight was 10 gr./m2, and the coating was applied to the side more smooth of the paper. The coated paper was dried at 150 ° C for 20 seconds. Approximately 30 grams of each paper were cut in 1.5cm. x 1.5cm. Two liters (lt.) Of water were added to each set of pieces to reach a consistency of 15gr./lt. The pH was adjusted in neutral using hydrochloric acid and sodium hydroxide. The paper was reduced again to paste in a British Moisture Disintegration device. The number of revolutions was 30,000. The paste was diluted with water until obtaining a resistance of 3gr./lt. The drainage capacity of the diluted paste was measured according to the Canadian Freeness method. Two measurements were carried out in parallel, and the results were expressed in milliliters. The small pieces of the coatings in the paste were observed under a microscope, looking for the magnitude of the coating pieces, and whether or not they had added pulp fibers to the coating pieces. The paste was again diluted to a consistency of 1.63 g / l. to make laboratory sheets of approximately 60gr./m2. The leaves were made with a special mold for leaves, and then dried in an oven for two hours in a way that they could not shrink. The tensile strength and elongation of the leaves were measured using ten parallel samples. The results of the tests described above are shown in Table 6. bla 6 Test Not covered Coverage Energy consumption (KWH) 1.7 1.7 Freenéss "Canadian (mi.) 890 900 Grams (gr '. / M2) 68.1 68.6 Elongation ( %) 3.4 3.9 Traction force (kN / m) 2.3 2.5 The above data shows that polymer-coated paper develops in the same way as paper not covered in tests designed to show the ability to be reduced back to pulp. The small pieces, observed under the microscope, showed traces of fibers, but the fibers were not added to the coating. These results indicate that the paper covered with polymer can be reduced back to paste.

Claims (15)

Claims

1. A method for modifying paper substrates, comprising: applying a polymer to the paper substrate, wherein the polymer comprises as polymerized units: a) from 1 to 100 parts by weight of at least one C 12 to C 0 alkyl ester of acid ( met) acrylic, b) from 0 to 90 parts by weight of at least one ethylenically unsaturated monomers, and e) from 0 to 15 parts by weight of at least one monomer containing ethylenically unsaturated acid or its salts.

2. The method according to claim 1, wherein the polymer comprises as polymerized units: a) from 5 to 95 parts by weight of at least one C1 to C40 alkyl ester of (meth) acrylic acid, b) from 4 to 94 parts by weight of at least one ethylenically unsaturated monomer and e) from 1 to 10 parts by weight of at least one monomer containing ethylenically unsaturated acid or its salts.

3. The method according to claim 1, wherein the polymer comprises as polymerized units: a) from 10 to 90 parts by weight of at least one alkyl ester Ci2 to C0 of (meth) acrylic acid, b) from 9 to 89 parts by weight of at least one ethylenically unsaturated monomer, and e) from 1 to 5 parts by weight of at least one monomer containing ethylenically unsaturated acid or its salts.

4. The method according to claim 1, wherein the polymer further comprises a binder.

5. The method according to claim 1, wherein the polymer further comprises a filler.

6. The method according to claim 1, wherein the paper substrate is selected from paperboard, corrugated cardboard, kraft paper and ream wrap.

7. The method according to claim 1, wherein the polymer is mixed with 50 to 99 parts by weight of a latex, and the mixture is applied to the paper substrate.

8. The method according to claim 7, wherein the polymer comprises as polymerized units: a) from 5 to 95 parts by weight of at least one ester of C12 to C40 alkyl of (meth) acrylic acid, b) from 4 to 94 parts by weight of at least one ethylenically unsaturated monomer, and e) from 1 to 10 parts by weight of at least a monomer containing ethylenically unsaturated acid and its salts.

9. The method according to claim 7, wherein the polymer comprises as polymerized units: a) from 10 to 90 parts by weight of at least one C1 to C40 alkyl ester of (meth) acrylic acid, b) from 9 to 89 parts by weight of at least one ethylenically unsaturated monomer, and e) from 1 to 5 parts by weight of at least one monomer containing ethylenically unsaturated acid or its salts.

10. The method according to claim 7, wherein the polymer further comprises a binder.

11. The method according to claim 7, wherein the polymer further comprises a filler.

12. The method according to claim 7, wherein the latex is selected from the group consisting of butyl acrylate / methyl methacrylate, butyl acrylate / styrene, styrene / butadiene and vinyl acetate latex.

13. The method according to claim 7, wherein the paper substrate is selected from paperboard, corrugated cardboard, kraft paper and ream wrap.

14. An article comprising: a paper substrate covered with the polymer of claim 1.

15. An article comprising: a paper substrate covered with the mixture of claim 7. Reminder The use of polymers in the form of barrier coatings for paper applications is revealed. The polymers provide water absorption and low water vapor transmission rates, as well as the ability to be reduced back to pulp.