A functional respiratory pvdc resin composition

Abstract

This application discloses a functional breathable PVDC resin composition comprising PVDC resin and an amino acid-modified polycarboxylate; the amino acid-modified polycarboxylate comprises at least one compound represented by Formula I: Formula I, wherein: R1-N- is an amino acid group; R2 and R3 are each independently selected from C4-C12 straight-chain alkylene or C4-C12 branched alkylene, and the total number of carbon atoms in R2 and R3 is less than 18; M1 and M2 each independently comprise Na + K + or Ca 2+ The functional breathable PVDC resin composition of this application can significantly improve the interaction between carboxylate and carbon dioxide, ultimately achieving multi-site absorption of CO2 by amine and carboxylate groups in PVDC resin, increasing the solubility of carbon dioxide in PVDC membrane, and thus increasing the carbon dioxide permeability, resulting in a higher CO2 permeability / O2 permeability ratio.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a functional breathable PVDC resin composition. Background Technology

[0002] Polyvinylidene chloride (PVDC) is a high-performance polymer material renowned for its exceptional barrier properties. It possesses extremely low gas permeability and excellent moisture resistance, effectively blocking the penetration of oxygen, water vapor, and odor molecules, thus significantly extending the shelf life of packaged goods (such as food and pharmaceuticals). This characteristic makes PVDC an ideal choice for food preservation and pharmaceutical protection. It has good film-forming properties and can be processed into films, coatings, or composite materials, widely used in blister packaging, composite film structures, and paper coating processes. Furthermore, PVDC exhibits good chemical resistance and thermal stability, maintaining its structural integrity even under high-temperature sterilization conditions. As a safe and environmentally friendly material, it meets multiple international food contact standards, combining functionality and sustainability, making it an indispensable key material in the modern packaging industry.

[0003] However, conventional PVDC materials only provide solutions for high-barrier packaging in the packaging industry, and do not offer good solutions for the field of inhalable packaging.

[0004] For example, related technology 1 discloses a method for preparing a VDC / MA copolymer PVDC composition. The method involves adding mixed monomers, chelating agents, dispersants, deionized water, pH adjusters, heat-stabilizing plasticizers, and composite initiators into a polymerization reactor and cold dispersing for 30 minutes. Then, the temperature is rapidly increased to 65°C at a stirring speed of 120 rpm to initiate polymerization. The temperature is then increased to 80°C–85°C at a stirring speed of 8 rpm / h–20 rpm / h and 3°C / h–5°C / h, and the stirring speed is increased to 170 rpm–180 rpm. Finally, the temperature is increased to 90°C at a stirring speed of 170 rpm–180 rpm and the temperature is maintained at 90°C for 1–2 hours to terminate polymerization. Residual monomers are removed under vacuum, and the mixture is cooled, discharged, centrifuged, and dried. Post-processing aids are added, and the temperature is increased to 80°C at a stirring speed of 25°C / h–30°C / h for mixing and maturation to obtain the composition. This PVDC composition exhibits good thermal stability during molding and processing and can be used in low-temperature food packaging in multilayer co-extruded films or co-extruded cast films. However, the drawback of this technology is that it mainly solves the need for high barrier protection of PVDC, but cannot solve the need for cheese packaging that requires high carbon dioxide permeability.

[0005] Related technology 2 discloses a vinylidene chloride copolymer composition for barrier films, comprising (a) a vinylidene chloride / methyl acrylate interpolymer having more than 6 wt% methyl acrylate monomer units, (b) more than 6 wt% epoxy plasticizer, and (c) less than 4 wt% acrylate polymer. The composition exhibits a crystallization time of more than 25 minutes at 35°C. Films prepared from this composition show improved processability and are advantageously suited for use as permeable barrier films in food packaging, specialty food packaging, and for gas-producing cheeses. While this technology provides good carbon dioxide permeability, ensuring rapid carbon dioxide removal during Lactobacillus fermentation in cheese to prevent bag bloating, its oxygen permeability is 117.85-707.1 cm⁻¹. 3 / m 2 The oxygen permeability of the sample was too high (tested at 23°C with a PVDC layer thickness of 5µm), which is not suitable for the survival of lactobacilli. Summary of the Invention

[0006] This application aims to at least partially address one of the technical problems in the related art.

[0007] Therefore, this application proposes a functional breathable PVDC resin composition. This composition contains amino acid-modified polycarboxylate, which can significantly improve the interaction between carboxylate and carbon dioxide, ultimately achieving multi-site absorption of CO2 by amine and carboxylate groups in the PVDC resin, increasing the solubility of carbon dioxide in the PVDC membrane, and thus increasing the carbon dioxide permeability, resulting in a higher CO2 permeability / O2 permeability ratio.

[0008] The functional breathable PVDC resin composition of this application includes PVDC resin and amino acid-modified polycarboxylate.

[0009] In some embodiments, the amino acid-modified polycarboxylate is a waxy substance.

[0010] In some embodiments, the amino acid-modified polycarboxylate includes at least one of the compounds represented by Formula I: Formula I, in: R1-N- represents an amino acid group; R2 and R3 are each independently selected from C4-C12 straight-chain alkylene or C4-C12 branched alkylene, and the total number of carbon atoms in R2 and R3 is less than 18; M1 and M2 each independently include Na + K + or Ca 2+ .

[0011] In some embodiments, the amino acid group includes one of lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, alanine, aspartic acid, glutamic acid, arginine, and histidine.

[0012] In some embodiments, the mass ratio of the PVDC resin to the amino acid-modified polycarboxylate is 100:(3-5).

[0013] In some embodiments, the functional breathable PVDC resin composition further includes polyethylene wax and oxidized polyethylene wax, wherein the mass ratio of the polyethylene wax, the oxidized polyethylene wax and the PVDC resin is (0.1-0.4):(0.1-0.4):100.

[0014] In some embodiments, the functional breathable PVDC resin composition further includes at least one of a plasticizer, an ethylene-vinyl acetate copolymer, and an antioxidant.

[0015] In some embodiments, the plasticizer includes at least one of acetylated tributyl citrate and epoxidized soybean oil.

[0016] In some embodiments, the mass ratio of the plasticizer to the PVDC resin is (3-5):100.

[0017] In some embodiments, the ethylene-vinyl acetate copolymer has a melt index of 4-8 g / 10 min at a temperature of 190°C and a load of 2.16 kg, and the mass content of vinyl acetate is 25-30%.

[0018] In some embodiments, the mass ratio of the ethylene-vinyl acetate copolymer to the PVDC resin is (3-5):100.

[0019] In some embodiments, the antioxidant includes at least one of antioxidant 1010 and antioxidant 1076.

[0020] In some embodiments, the mass ratio of the antioxidant to the PVDC resin is (0.2-0.4):100.

[0021] In some embodiments, the plasticizer is tributyl acetyl citrate and epoxidized soybean oil, and the mass ratio of tributyl acetyl citrate to epoxidized soybean oil is (1-2):(2-3).

[0022] In some embodiments, the antioxidant is antioxidant 1010 and antioxidant 1076, and the mass ratio of antioxidant 1010 to antioxidant 1076 is (0.1-0.2):(0.1-0.2).

[0023] In some embodiments, the functional breathable PVDC resin composition includes PVDC resin, amino acid-modified polycarboxylate, polyethylene wax, oxidized polyethylene wax, plasticizer, ethylene-vinyl acetate copolymer, and antioxidant.

[0024] In some embodiments, the PVDC resin has a weight-average molecular weight of 91,873-97,382 Daltons (Da), a polydispersity index of 1.32-1.45, and a D50 particle size of 261-292 μm.

[0025] The functional breathable PVDC resin composition described in this application can bring at least the following beneficial effects: 1. Due to the presence of amino acid-modified polycarboxylate, especially when the amino acid-modified polycarboxylate is an amino acid-modified polycarboxylate with a suitable carbon chain length, the interaction between carboxylate and carbon dioxide can be significantly improved. This ultimately enables the multi-site absorption of CO2 by the amine and carboxylate groups in the PVDC resin, increases the solubility of carbon dioxide in the PVDC membrane, and thus increases the carbon dioxide permeability, resulting in a higher CO2 permeability / O2 permeability ratio.

[0026] 2. Select EVA (e.g., EVA powder) with a melt index range of 4-8 g / 10 min and a VA content of 25-30%. Within this melt index range, the processing temperature is close to that of PVDC resin, resulting in better compatibility and a better internal plasticizing effect, thus improving processing stability. Controlling the VA content at 25%-30% avoids the problems of excessive melt pressure due to excessive VA content and poor compatibility between EVA and PVDC due to excessively low VA content. Furthermore, the addition of EVA helps increase the gas permeability of the PVDC membrane.

[0027] 3. Polyethylene wax, oxidized polyethylene wax, and amino acid-modified polycarboxylate can melt well at high temperatures and then be adsorbed onto the resin surface, which can ensure that the resin has good melt pressure stability.

[0028] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Detailed Implementation

[0029] The embodiments of this application are described in detail below. These embodiments are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0030] In this application, the disclosure of numerical ranges includes all values ​​throughout the range and the disclosure of further subdivisions of the range, including the endpoints and subranges given for these ranges.

[0031] Unless otherwise specified, all raw materials and equipment involved in this application are self-made through commercial means or known methods; and all methods involved are conventional methods unless otherwise specified.

[0032] The functional breathable PVDC resin composition of this application includes PVDC resin and amino acid-modified polycarboxylate.

[0033] Because this composition contains amino acid-modified polycarboxylate, it can significantly improve the interaction between carboxylate and carbon dioxide, ultimately achieving multi-site absorption of CO2 by amine and carboxylate groups in PVDC resin, increasing the solubility of carbon dioxide in PVDC membrane, and thus increasing the carbon dioxide permeability, resulting in a higher CO2 permeability / O2 permeability ratio.

[0034] In some embodiments, the amino acid-modified polycarboxylate is a waxy substance.

[0035] In some embodiments, the amino acid-modified polycarboxylate includes at least one of the compounds represented by Formula I: Formula I, in: R1-N- represents an amino acid group; R2 and R3 are each independently selected from C4-C12 straight-chain alkylene or C4-C12 branched alkylene, and the total number of carbon atoms in R2 and R3 is less than 18; M1 and M2 are each independent of, but not limited to, Na. + K + or Ca 2+ wait.

[0036] In the embodiments of this application, alkylene refers to a divalent group formed by removing one hydrogen atom from each end of an alkane.

[0037] In some embodiments, the number of carbon atoms in the C4-C12 straight-chain alkylene and the C4-C12 branched alkylene are each independently 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0038] For example, C4-C12 straight-chain alkylene groups include, but are not limited to, 1,4-butylene (-CH2CH2CH2CH2-), 1,5-pentylene (-CH2(CH2)3CH2-), 1,6-hexylene (-CH2(CH2)4CH2-), 1,7-heptylene (-CH2(CH2)5CH2-), 1,8-octylene (-CH2(CH2)6CH2-), 1,9-nonylene (-CH2(CH2)7CH2-), 1,10-decylene (-CH2(CH2)8CH2-), or 1,11-undecylene (-CH2(CH2)9CH2-).

[0039] For example, C4-C12 branched alkylene groups include, but are not limited to, 2-methyl-1,3-propylidene (-CH2-CH(CH3)-CH2-), 2,2-dimethyl-1,3-propylidene (-CH2-C(CH3)2-CH2-), 3-methyl-1,5-pentylidene (-CH2CH2-CH(CH3)-CH2CH2-), 3-ethyl-1,5-pentylidene (-CH2CH2-CH(CH2CH3)-CH2CH2-), 2,5-dimethyl-1,6-hexylidene (-CH2-CH(CH3)-CH2CH2-CH(CH3)-CH2-), or 2,4,7-trimethyl-1,8-octylidene (-CH2-CH(CH3)-CH2-CH(CH3)-CH2CH2-CH(CH3)-CH2-).

[0040] In the embodiments of this application, the compound represented by Formula I is an amino acid-modified polycarboxylate with a suitable carbon chain length. Selecting it as the amino acid-modified polycarboxylate in the composition of this application embodiment can better achieve the following effects: significantly improve the interaction between carboxylate and carbon dioxide, ultimately realize the multi-site absorption of CO2 by amine and carboxylate groups in PVDC resin, improve the solubility of carbon dioxide in PVDC membrane, and thus improve the carbon dioxide permeability, resulting in a higher CO2 permeability / O2 permeability ratio.

[0041] As an optional example, the amino acid-modified polycarboxylate is a compound represented by Formula I above. Further optionally, M1 and M2 are the same.

[0042] It is understandable that when both M1 and M2 are Na + When the amino acid-modified polycarboxylate is sodium salt; when both M1 and M2 are K... + When the amino acid-modified polycarboxylate is a potassium salt; when both M1 and M2 are Ca... 2+ In this case, the amino acid-modified polycarboxylic acid salt is a calcium salt.

[0043] In some embodiments, the amino acid group includes, but is not limited to, one of the following: lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, alanine, aspartic acid, glutamic acid, arginine, and histidine.

[0044] It should be noted that in the embodiments of this application, the above-mentioned amino acid groups can all achieve good results, but from the perspective of cost, the glutamic acid route is more mature and has a lower cost, so the glutamic acid group can be selected.

[0045] In the embodiments of this application, the compounds represented by Formula I can be obtained in-house or commercially through known methods.

[0046] In some embodiments, the mass ratio of the PVDC resin to the amino acid-modified polycarboxylate is 100:(3-5), including but not limited to 100:3.25, 100:3.5, 100:3.75, 100:4, 100:4.25, 100:4.5 or 100:4.75.

[0047] In the embodiments of this application, controlling the mass ratio of PVDC resin and amino acid-modified polycarboxylate within the above-mentioned range can achieve a balance between oxygen barrier performance and carbon dioxide permeability, thus achieving the best inventive effect; if the ratio is lower than 100:5, the oxygen permeability is too high, which is not conducive to the survival of living organisms such as lactic acid bacteria, Lactobacillus casei, and Lactobacillus plantarum; if the ratio is higher than 100:3, the solubilization effect is poor, which is not conducive to the rapid expulsion of carbon dioxide.

[0048] In some embodiments, the functional breathable PVDC resin composition further includes polyethylene wax and oxidized polyethylene wax.

[0049] In the embodiments of this application: The function of oxidized polyethylene wax is to lubricate the screw, barrel, and die, and to improve the flow properties of PVDC melt. Oxidized polyethylene wax is also known as OPE wax, and sometimes simply as oxidized wax.

[0050] The function of polyethylene wax is to lubricate the screw, barrel, and die head, and to improve the flow properties of PVDC melt.

[0051] In some embodiments, the mass ratio of the polyethylene wax, the oxidized polyethylene wax, and the PVDC resin is (0.1-0.4):(0.1-0.4):100, including but not limited to 0.1:0.25:100, 0.1:0.2:100, 0.1:0.3:100, 0.2:0.1:100, 0.2:0.25:100, 0.2:0.3:100, 0.25:0.25:100, 0.25:0.2:100, 0.25:0.3:100, 0.25:0.4:100, 0.3:0.25:100, or 0.3:0.4:100, etc.

[0052] In some embodiments, the functional breathable PVDC resin composition further includes at least one of a plasticizer, ethylene-vinyl acetate copolymer (EVA), and an antioxidant.

[0053] In the embodiments of this application: The role of plasticizers is twofold: firstly, by inserting themselves between resin molecular chains, they increase the interchain spacing, weaken intermolecular forces, and make the molecular chains easier to slide. This significantly improves the plasticity of the resin during processing and imparts good softness to the final product; secondly, they reduce the viscosity of the resin melt, improve fluidity, make injection molding, extrusion and other processes easier to operate, and lower the processing temperature.

[0054] The role of ethylene-vinyl acetate copolymer is to improve the strength and ductility of the melt, making the melt less prone to cracking and more stable in processing; it has better adhesion, improves the compatibility of PVDC with amino acid-modified polycarboxylate, plasticizers, antioxidants and other additives, and improves the adhesion strength between the PVDC layer and other adjacent layers; and it is beneficial to improve the gas permeability of PVDC membrane.

[0055] The role of antioxidants is twofold: on the one hand, to block the degradation process and extend the life of materials by capturing free radicals or decomposing peroxides; on the other hand, to prevent resin from yellowing, becoming embrittled, and experiencing a decline in mechanical properties.

[0056] In some embodiments, the plasticizer includes, but is not limited to, at least one of acetylated tributyl citrate (ATBC), epoxidized soybean oil (ESO), etc.

[0057] In some embodiments, the mass ratio of the plasticizer to the PVDC resin is (3-5):100, including but not limited to 3.25:100, 3.5:100, 3.75:100, 4:100, 4.25:100 or 4.5:100, etc.

[0058] As an optional example, the plasticizer is tributyl acetyl citrate (ATBC) and epoxidized soybean oil (ESO), and the mass ratio of tributyl acetyl citrate to epoxidized soybean oil is (1-2):(2-3), including but not limited to 1:2.5, 2:2.5, 1.5:2.5, 1.5:2, 1.5:3 or 1.5:2.5, etc.

[0059] In some embodiments, the ethylene-vinyl acetate copolymer (EVA) is ethylene-vinyl acetate copolymer powder (i.e., EVA powder).

[0060] In some embodiments, the ethylene-vinyl acetate copolymer has a melt index of 4-8 g / 10 min at a temperature of 190°C and a load of 2.16 kg, and the mass content of vinyl acetate (VA) is 25-30%.

[0061] Ethylene-vinyl acetate copolymer, especially ethylene-vinyl acetate copolymer powder, with a melt index of 4-8 g / 10 min was selected under conditions of 190℃ and 2.16 kg load. Its processing temperature is close to that of PVDC resin, resulting in better compatibility and a better internal plasticizing effect, thus improving processing stability. Simultaneously, the VA content of the ethylene-vinyl acetate copolymer, especially the ethylene-vinyl acetate copolymer powder, was controlled at 25%-30%. This avoids the problem of high melt pressure due to excessive VA content, and also avoids the problem of poor compatibility between EVA and PVDC due to excessively low VA content.

[0062] For example, the melt index of the ethylene-vinyl acetate copolymer at a temperature of 190°C and a load of 2.16 kg includes, but is not limited to, 4.5 g / 10 min, 5 g / 10 min, 5.5 g / 10 min, 6 g / 10 min, 6.5 g / 10 min, 7 g / 10 min, or 7.5 g / 10 min.

[0063] For example, the mass content of vinyl acetate (VA) in the ethylene-vinyl acetate copolymer includes, but is not limited to, 26%, 27%, 28%, or 29%.

[0064] In some embodiments, the mass ratio of the ethylene-vinyl acetate copolymer to the PVDC resin is (3-5):100, including but not limited to 3.25:100, 3.5:100, 3.75:100, 4:100, 4.25:100 or 4.5:100.

[0065] In some embodiments, the antioxidant includes, but is not limited to, at least one of antioxidant 1010, antioxidant 1076, etc.

[0066] In some embodiments, the mass ratio of the antioxidant to the PVDC resin is (0.2-0.4):100, including but not limited to 0.22:100, 0.25:10, 0.27:100, 0.3:100, 0.32:100, 0.34:100, 0.36:100, or 0.38:100.

[0067] As an optional example, the antioxidant is antioxidant 1010 and antioxidant 1076, and the mass ratio of antioxidant 1010 and antioxidant 1076 is (0.1-0.2):(0.1-0.2), including but not limited to 0.1:0.15, 0.2:0.15, 0.15:0.1, 0.15:0.2, or 0.15:0.15, etc.

[0068] In some embodiments, the functional breathable PVDC resin composition includes, but is not limited to, PVDC resin, amino acid-modified polycarboxylate, polyethylene wax, oxidized polyethylene wax, plasticizer, ethylene-vinyl acetate copolymer, and antioxidant.

[0069] As an optional example, the functional breathable PVDC resin composition comprises: 100 parts by weight of PVDC resin, 3-5 parts by weight of plasticizer, 3-5 parts by weight of EVA powder, 0.1-0.4 parts by weight of oxidized polyethylene wax, 0.1-0.4 parts by weight of polyethylene wax, 0.2-0.4 parts by weight of antioxidant, and 3-5 parts by weight of amino acid-modified polycarboxylate.

[0070] Further optionally, the functional breathable PVDC resin composition comprises: 100 parts by weight of PVDC resin, 3-5 parts by weight of plasticizer (including 1-2 parts by weight of ESO and 2-3 parts by weight of ATBC), 3-5 parts by weight of EVA powder, 0.1-0.4 parts by weight of oxidized polyethylene wax, 0.1-0.4 parts by weight of polyethylene wax, 0.2-0.4 parts by weight of antioxidant (including 0.1-0.2 parts by weight of antioxidant 1010 and 0.1-0.2 parts by weight of antioxidant 1076), and 3-5 parts by weight of amino acid-modified polycarboxylate.

[0071] It should be noted that when the amount of amino acid-modified polycarboxylate is too large, the barrier properties are severely damaged, which is not conducive to the reproduction of live organisms such as lactic acid bacteria, Lactobacillus casei, and Lactobacillus plantarum. When the amount of amino acid-modified polycarboxylate is too small, the CO2 solubilization effect is poor, and the CO2 transmission rate / O2 transmission rate ratio is low. When the amount of ethylene-vinyl acetate copolymer (EVA) is too large, the melt viscosity is too high and the processing performance is poor. When the amount of ethylene-vinyl acetate copolymer (EVA) is too small, the melt strength is poor and the melt is prone to cracking.

[0072] As an alternative example, the functional breathable PVDC resin composition comprises PVDC resin, amino acid-modified polycarboxylate, polyethylene wax, oxidized polyethylene wax, plasticizer, ethylene-vinyl acetate copolymer, and antioxidant.

[0073] Further optionally, the functional breathable PVDC resin composition comprises: 100 parts by weight of PVDC resin, 2-3 parts by weight of ESO, 1-2 parts by weight of ATBC, 3-5 parts by weight of EVA powder, 0.1-0.4 parts by weight of oxidized polyethylene wax, 0.1-0.4 parts by weight of polyethylene wax, 0.1-0.2 parts by weight of antioxidant 1010, 0.1-0.2 parts by weight of antioxidant 1076, and 3-5 parts by weight of amino acid-modified polycarboxylate.

[0074] In some embodiments, the PVDC resin has a weight-average molecular weight (Mw) of 91,873-97,382 Daltons (Da), a polydispersity index (Mw / Mn) of 1.32-1.45, and a D50 particle size of 261-292 μm.

[0075] For example, the weight-average molecular weight of the PVDC resin includes, but is not limited to, 92,000 Daltons (Da), 93,000 Daltons (Da), 94,000 Daltons (Da), 95,000 Daltons (Da), or 96,000 Daltons (Da).

[0076] For example, the polydispersity index of the PVDC resin includes, but is not limited to, 1.34, 1.36, 1.38, 1.40 or 1.42.

[0077] For example, the D50 particle size of the PVDC resin includes, but is not limited to, 265μm, 270μm, 275μm, 280μm or 285μm.

[0078] In some embodiments, the method for preparing the PVDC resin includes: subjecting the reactants to a suspension polymerization reaction and then adding a reaction terminator to terminate the reaction.

[0079] In some embodiments, the reaction raw materials include vinylidene chloride monomer (VDC monomer) and comonomer, wherein the comonomer includes, but is not limited to, at least one of vinyl chloride (VC), methyl methacrylate (MMA) and acrylonitrile (AN).

[0080] In some embodiments, the mass ratio of the vinylidene chloride monomer, comonomer, and reaction terminator is (850-900):(100-150):(18-24), including but not limited to 860:125:21, 870:125:21, 880:125:21, 890:125:21, 860:110:21, 870:130:21, 880:140:21, 890:110:21, 860:135:21, 870:135:21, 880:135:21, 890:135:21, 860:125:18, 870:130:23, 880:125:24, or 890:115:22, etc.

[0081] In some embodiments, the reaction terminator includes, but is not limited to, at least one of triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate (IRG-245), diethylhydroxylamine, hydroquinone, etc., and may be selected as IRG-245.

[0082] In some embodiments, the reaction raw materials also include water, dispersant, pH buffer and initiator.

[0083] For example, the water includes, but is not limited to, deionized water, pure water, ultrapure water, distilled water, etc., and may be selected as deionized water.

[0084] For example, the dispersant includes, but is not limited to, at least one of hydroxypropyl cellulose, hydroxypropyl methylcellulose, methylcellulose, and methylcellulose ether.

[0085] For example, the pH buffer includes, but is not limited to, at least one of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium pyrophosphate, sodium carbonate, and sodium bicarbonate.

[0086] For example, the initiator includes, but is not limited to, at least one of benzoyl peroxide, tert-butyl peroxide-2-ethylhexanoate, and tert-butyl peroxide isobutyrate.

[0087] As an optional example, the reaction raw materials include: 1170-1304 parts by weight of water, 1.2-1.4 parts by weight of dispersant, 0.5-0.8 parts by weight of pH buffer, 3-3.5 parts by weight of initiator, 850-900 parts by weight of VDC monomer, and 100-150 parts by weight of comonomer.

[0088] For example, the water content in the reaction raw materials includes, but is not limited to, 1200 parts by weight, 1220 parts by weight, 1240 parts by weight, 1260 parts by weight, or 1280 parts by weight; the dispersant content includes, but is not limited to, 1.22 parts by weight, 1.25 parts by weight, 1.28 parts by weight, 1.3 parts by weight, 1.32 parts by weight, 1.35 parts by weight, or 1.38 parts by weight; the pH buffer content includes, but is not limited to, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight, 0.7 parts by weight, or 0.75 parts by weight; and the initiator content includes, but is not limited to, 3.1 parts by weight, 3.2 parts by weight, 3.3 parts by weight, or 3.4 parts by weight.

[0089] In some embodiments, the reaction temperature of the suspension polymerization reaction is controlled by a variable temperature method. As the reaction proceeds, the initiator decays, and the reactivity weakens. This application uses a variable temperature method to control the polymerization temperature, gradually increasing the polymerization temperature to ensure the reactivity in the later stages, thus obtaining a PVDC resin with a suitable molecular weight and uniform molecular weight distribution.

[0090] Optionally, the suspension polymerization reaction includes a first reaction stage, a second reaction stage, and a third reaction stage, wherein the reaction temperature of the first reaction stage, the reaction temperature of the second reaction stage, and the reaction temperature of the third stage increase sequentially.

[0091] For example, the reaction temperature of the first reaction stage is 71-74°C, including but not limited to 72°C or 73°C.

[0092] For example, the reaction temperature of the second reaction stage is 76-80°C, including but not limited to 77°C, 78°C or 79°C.

[0093] For example, the reaction temperature of the third stage is 81-85℃, including but not limited to 82℃, 83℃ or 84℃.

[0094] For example, the reaction time of the first reaction stage is 0.5-1.5 hours, such as 1 hour.

[0095] For example, the reaction time of the second reaction stage and the time of the third reaction stage are each independently 2-4 hours, such as 3 hours.

[0096] In some embodiments, the method for preparing the PVDC resin further includes: After terminating the reaction by adding a reaction terminator, purification, drying, and sieving steps are performed.

[0097] For example, the purification includes vacuum desorption. The purpose of purification is to remove residual monomers.

[0098] For example, the sieving includes a first sieving and a second sieving performed sequentially, wherein the particle size of the first sieving is larger than that of the second sieving. The purpose of the first sieving is to remove resin particles that are too large, and the purpose of the second sieving is to remove resin particles that are too small.

[0099] For example, the first screening is performed using a 40-mesh sieve, and the second screening is performed using an 80-mesh sieve.

[0100] In the embodiments of this application, a suitable sieve is used to sieve the resin, and PVDC resin with uniform particle size is obtained. This ensures the stability of melt pressure during resin processing and good basic processing performance.

[0101] As an optional example, in an embodiment of this application, the method for preparing the PVDC resin includes the following steps: (1) Prepare materials for use: Weigh 1170-1304 parts by weight of water, 1.2-1.4 parts by weight of dispersant, 0.5-0.8 parts by weight of pH buffer, 18-24 parts by weight of reaction terminator, 3-3.5 parts by weight of initiator, 850-900 parts by weight of VDC monomer, and 100-150 parts by weight of comonomer.

[0102] (2) Prepare pH buffer solution and dispersant solution for later use: Mix 0.5-0.8 parts by weight of pH buffer with 10-20 parts by weight of water to obtain pH buffer solution; mix 1.2-1.4 parts by weight of dispersant with 200-280 parts by weight of water to obtain dispersant solution.

[0103] (3) Prepare mixed monomers: Mix VDC monomers and comonomers evenly and set aside (prepare VC monomers separately if available) to obtain mixed monomers.

[0104] (4) Adding additives: First, replace with nitrogen or / and inert gas and evacuate twice to reduce the pressure of the polymerization reactor to -0.095 to -0.098 MPa. Add mixed monomers (if there is VC monomer, add VC monomer first and then add mixed monomers) and initiator and stir for 15-30 minutes. Then, under stirring at 35-50 rpm, add 1170-1304 parts by mass of deionized water, pH buffer solution, dispersant solution and rinsing water (the amount of rinsing water can be, for example, 40-60 parts by mass). Disperse cold for 15-30 minutes to obtain the reaction solution.

[0105] (5) Resin synthesis: The reaction solution is stirred at a speed of 35-50 rpm for 8 hours. The reaction temperature is 71-74℃ for the first hour, 76-80℃ for the second to fourth hours, and 81-85℃ for the fifth to eighth hours. After the reaction is completed, 18-24 parts by mass of reaction terminator (e.g., IRG-245) and 21-24 parts by mass of reaction terminator are added to terminate the reaction. The residual monomer is removed by vacuum desorption and then dried (e.g., centrifugal drying) to obtain the PVDC resin to be screened.

[0106] (6) Resin sieving: Use a 40-mesh sieve to remove resin particles that are too large from the PVDC resin to be sieved, and then use an 80-mesh sieve to remove resin particles that are too small, so as to obtain PVDC resin with uniform particle size.

[0107] In step (1) of the above-mentioned PVDC resin preparation method, the 1170-1304 parts by mass of water are only the deionized water added in step (4) under the stirring state of 35-50 rpm, and do not include the water used in step (2) to prepare the pH buffer aqueous solution and the dispersant aqueous solution, or the rinsing water in step (4). The water used in step (2) to prepare the pH buffer aqueous solution and the dispersant aqueous solution, and the rinsing water in step (4) are added separately.

[0108] In some embodiments, a method for preparing functional breathable PVDC resin using the functional breathable PVDC resin composition of the present application as a raw material includes the following steps: (a) An antioxidant is added to the PVDC resin for a first mixing to obtain a first mixture; (b) Add ethylene-vinyl acetate copolymer, oxidized polyethylene wax, polyethylene wax, antioxidant and amino acid modified polycarboxylate to the first mixture for a second mixture to obtain a second mixture; (c) The second mixture is sieved to remove agglomerated materials to obtain the finished resin.

[0109] In some embodiments, the temperatures of the first mixture and the second mixture are each independently 50-70°C, including but not limited to 55°C, 60°C, or 65°C.

[0110] In some implementations, the first mixing time is 0.5-1 hour, for example, 0.75 hours.

[0111] In some implementations, the second mixing time is 1-2 hours, for example 1.5 hours.

[0112] In some implementations, in step (c), sieving is performed using a 20-mesh sieve.

[0113] As an optional example, a method for preparing functional breathable PVDC resin using the functional breathable PVDC resin composition of the embodiments of this application as a raw material includes the following steps: Weigh 100 parts by weight of PVDC resin, add 2-3 parts by weight of ESO and 1-2 parts by weight of ATBC, and mix at 50-70℃ for 0.5-1h; then add 3-5 parts by weight of EVA powder, 0.1-0.4 parts by weight of oxidized polyethylene wax, 0.1-0.4 parts by weight of polyethylene wax, 0.1-0.2 parts by weight of antioxidant 1010, 0.1-0.2 parts by weight of antioxidant 1076, and 3-5 parts by weight of amino acid modified polycarboxylate, and mix at 50-70℃ for 1-2h; finally remove agglomerated materials with a 20-mesh sieve to obtain the finished resin.

[0114] In summary, the functional breathable PVDC resin prepared using the functional breathable PVDC resin composition of the embodiments of this application as raw material has a uniform molecular weight distribution, narrow particle size distribution, low melt pressure with small fluctuations, and both low oxygen permeability and high carbon dioxide permeability, making it particularly suitable for packaging cheese and the like.

[0115] The following non-limiting embodiments further illustrate certain features of the present technology.

[0116] I. Examples and Comparative Examples In the following examples and comparative examples, the average particle size of the EVA powder is 282 μm.

[0117] In the following embodiments, the deionized water involved in the reaction raw materials in step (1) is only the deionized water added in step (4), and does not include the deionized water used in step (2) to prepare the pH buffer solution and dispersant solution, nor does it include rinsing water.

[0118] In all the following embodiments, deionized water is used for rinsing.

[0119] All amino acid-modified polycarboxylate salts involved in the following examples and comparative examples can be synthesized by conventional methods or purchased commercially. Unless otherwise specified, all other raw materials and reagents can be purchased commercially. For example, oxidized polyethylene wax can be OW-0528B produced by Nanjing Tianshi New Material Technology Co., Ltd., etc.

[0120] Example 1 This embodiment provides a functional breathable PVDC resin composition, which consists of: 100 parts by weight of PVDC resin, 2 parts by weight of ESO, 1 part by weight of ATBC, 3 parts by weight of EVA powder, 0.2 parts by weight of oxidized polyethylene wax, 0.3 parts by weight of polyethylene wax, 0.15 parts by weight of antioxidant 1010, 0.15 parts by weight of antioxidant 1076, and 3 parts by weight of amino acid modified polycarboxylate.

[0121] in: The EVA powder has a melt index of 5 g / 10 min at a temperature of 190℃ and a load of 2.16 kg, and a VA mass content of 25%.

[0122] The amino acid-modified polycarboxylate is a glutamic acid-modified carboxylate, with the following structural formula: R1 is an N-glutamic acid group, R2 and R3 are both C6 straight-chain alkylene groups (i.e., -CH2(CH2)4CH2-), and M1 and M2 are both Na groups. + .

[0123] The PVDC resin in the functional breathable PVDC resin composition is prepared in-house, and its preparation method includes the following steps: (1) Prepare materials for use: Weigh 1170 parts by weight of deionized water, 1.2 parts by weight of hydroxymethyl cellulose, 0.5 parts by weight of sodium pyrophosphate, 21 parts by weight of reaction terminator IRG-245, 3 parts by weight of benzoyl peroxide, 850 parts by weight of VDC monomer, 100 parts by weight of AN monomer and 50 parts by weight of MMA monomer.

[0124] (2) Prepare pH buffer solution and dispersant solution for later use: Weigh 1.2 parts by mass of hydroxymethyl cellulose and add 240 parts by mass of deionized water and mix well to obtain dispersant solution; Weigh 0.5 parts by mass of sodium pyrophosphate and add 10 parts by mass of deionized water and mix well to obtain pH buffer solution.

[0125] (3) Preparation of mixed monomers: Mix 850 parts by mass of VDC monomer, 100 parts by mass of AN monomer and 50 parts by mass of MMA monomer evenly to obtain mixed monomers.

[0126] (4) Adding additives: First, replace with nitrogen and evacuate twice to reduce the pressure of the polymerization reactor to -0.095 MPa. Add mixed monomers and initiator benzoyl peroxide and stir at 35 rpm for 15 minutes. Then, add 1170 parts by weight of deionized water, pH buffer solution, dispersant solution and 50 parts by weight of rinsing water while stirring at 35 rpm. Disperse cold for 15 minutes to obtain the reaction solution.

[0127] (5) Resin synthesis: The reaction solution was stirred at 35 rpm for 8 hours. The reaction temperature was 70°C for the first hour, 75°C for the second to fourth hours, and 80°C for the fifth to eighth hours. After the reaction was completed, 21 parts by mass of the reaction terminator IRG-245 were added to terminate the reaction. The residual monomer was removed by vacuum desorption, and then the product was centrifuged and dried to obtain the PVDC resin to be screened.

[0128] (6) Resin sieving: Use a 40-mesh sieve to remove resin particles that are too large from the PVDC resin to be sieved, and then use an 80-mesh sieve to remove resin particles that are too small, so as to obtain PVDC resin with uniform particle size.

[0129] The method for preparing functional breathable PVDC resin using the functional breathable PVDC resin composition of this embodiment as raw material includes the following steps: 1) Add ATBC and ESO to PVDC resin and mix at 50°C for 0.5 h to obtain the first mixture.

[0130] 2) Add EVA powder, oxidized polyethylene wax, polyethylene wax, antioxidant 1010, antioxidant 1076 and amino acid modified polycarboxylate to the first mixture, and mix at 50°C for 1 hour to obtain the second mixture.

[0131] 3) Remove the agglomerated material from the second mixture using a 20-mesh sieve to obtain the finished resin.

[0132] Example 2 This embodiment provides a functional breathable PVDC resin composition, which comprises: 100 parts by weight of PVDC resin, 2.2 parts by weight of ESO, 1.2 parts by weight of ATBC, 3.2 parts by weight of EVA powder, 0.3 parts by weight of oxidized polyethylene wax, 0.2 parts by weight of polyethylene wax, 0.1 parts by weight of antioxidant 1010, 0.1 parts by weight of antioxidant 1076, and 3.8 parts by weight of amino acid modified polycarboxylate.

[0133] in: The EVA powder has a melt index of 4 g / 10 min at a temperature of 190℃ and a load of 2.16 kg, and a VA mass content of 26%.

[0134] The amino acid-modified polycarboxylate is a glutamic acid-modified carboxylate, with the following structural formula: In this system, R1 is an N-glutamic acid group, R2 is a C5 straight-chain alkylene group (i.e., -CH2(CH2)3CH2-), R3 is a C9 straight-chain alkylene group (i.e., -CH2(CH2)7CH2-), and M1 and M2 are both K. + .

[0135] The PVDC resin in the functional breathable PVDC resin composition is prepared in-house, and its preparation method includes the following steps: (1) Prepare materials for use: Weigh 1238 parts by weight of deionized water, 1.25 parts by weight of hydroxypropyl cellulose, 0.6 parts by weight of disodium hydrogen phosphate, 22 parts by weight of reaction terminator IRG-245, 3.2 parts by weight of tert-butyl peroxide-2-ethylhexanoate, 860 parts by weight of VDC monomer, 60 parts by weight of AN monomer and 80 parts by weight of VC monomer.

[0136] (2) Prepare pH buffer solution and dispersant solution for later use: Weigh 1.25 parts by weight of hydroxypropyl cellulose and add 250 parts by weight of deionized water and mix well to obtain dispersant solution; Weigh 0.6 parts by weight of disodium hydrogen phosphate and add 12 parts by weight of deionized water and mix well to obtain pH buffer solution.

[0137] (3) Prepare the mixed monomer and VC monomer: Mix 860 parts by mass of VDC monomer and 60 parts by mass of AN monomer evenly to obtain the mixed monomer; at the same time, prepare 80 parts by mass of VC monomer.

[0138] (4) Adding additives: First, replace with nitrogen and evacuate twice to reduce the pressure of the polymerization reactor to -0.096 MPa. First, add VC monomer, then add mixed monomers and initiator tert-butyl peroxide-2-ethylhexanoate. Stir at 40 rpm for 20 minutes. Then, while stirring at 40 rpm, add 1238 parts by mass of deionized water, pH buffer solution, dispersant solution and 50 parts by mass of rinsing water. Disperse cold for 20 minutes to obtain the reaction solution.

[0139] (5) Resin synthesis: The reaction solution was stirred at 40 rpm for 8 hours. The reaction temperature was 71°C for the first hour, and then uniformly increased to 76°C for the second to fourth hours. The reaction temperature was uniformly increased to 81°C for the fifth to eighth hours. After the reaction was completed, 22 parts by mass of the reaction terminator IRG-245 were injected to terminate the reaction. The residual monomer was removed by vacuum desorption, and then the product was centrifuged and dried to obtain the PVDC resin to be screened.

[0140] (6) Resin sieving: Use a 40-mesh sieve to remove resin particles that are too large from the PVDC resin to be sieved, and then use an 80-mesh sieve to remove resin particles that are too small, so as to obtain PVDC resin with uniform particle size.

[0141] The method for preparing functional breathable PVDC resin using the functional breathable PVDC resin composition of this embodiment as raw material includes the following steps: 1) Add ATBC and ESO to PVDC resin and mix at 55°C for 1 hour to obtain the first mixture.

[0142] 2) Add EVA powder, oxidized polyethylene wax, polyethylene wax, antioxidant 1010, antioxidant 1076 and amino acid modified polycarboxylate to the first mixture, and mix at 55°C for 1.5 h to obtain the second mixture.

[0143] 3) Remove the agglomerated material from the second mixture using a 20-mesh sieve to obtain the finished resin.

[0144] Example 3 This embodiment provides a functional breathable PVDC resin composition, which comprises: 100 parts by weight of PVDC resin, 2.4 parts by weight of ESO, 1.5 parts by weight of ATBC, 3.5 parts by weight of EVA powder, 0.4 parts by weight of oxidized polyethylene wax, 0.1 parts by weight of polyethylene wax, 0.1 parts by weight of antioxidant 1010, 0.2 parts by weight of antioxidant 1076, and 4.5 parts by weight of amino acid modified polycarboxylate.

[0145] in: The EVA powder has a melt index of 6 g / 10 min at a temperature of 190℃ and a load of 2.16 kg, and a VA mass content of 28%.

[0146] The amino acid-modified polycarboxylate is a glutamic acid-modified carboxylate, with the following structural formula: R1 is an N-glutamic acid group, R2 and R3 are both C7 straight-chain alkylene groups (i.e., -CH2(CH2)5CH2-), and M1 and M2 are both Na groups. + .

[0147] The PVDC resin in the functional breathable PVDC resin composition is prepared in-house, and its preparation method includes the following steps: (1) Prepare materials for use: Weigh 1266 parts by weight of deionized water, 1.35 parts by weight of hydroxypropyl methylcellulose, 0.7 parts by weight of sodium dihydrogen phosphate, 24 parts by weight of reaction terminator IRG-245, 3.4 parts by weight of tert-butyl peroxide, 870 parts by weight of VDC monomer, 70 parts by weight of AN monomer and 60 parts by weight of MMA monomer.

[0148] (2) Prepare pH buffer solution and dispersant solution for later use: Weigh 1.35 parts by mass of hydroxypropyl methylcellulose and add 270 parts by mass of deionized water and mix well to obtain dispersant solution; Weigh 0.7 parts by mass of sodium dihydrogen phosphate and add 14 parts by mass of deionized water and mix well to obtain pH buffer solution.

[0149] (3) Preparation of mixed monomers: Mix 870 parts by mass of VDC monomer, 70 parts by mass of AN monomer and 60 parts by mass of MMA monomer evenly to obtain mixed monomers.

[0150] (4) Adding additives: First, replace with nitrogen and evacuate twice to reduce the pressure of the polymerization reactor to -0.097 MPa. Add mixed monomers and initiator tert-butyl peroxide and stir at 45 rpm for 25 minutes. Then, add 1266 parts by mass of deionized water, pH buffer solution, dispersant solution and 50 parts by mass of rinsing water while stirring at 45 rpm. Disperse cold for 25 minutes to obtain the reaction solution.

[0151] (5) Resin synthesis: The reaction solution was stirred at 45 rpm for 8 hours. The reaction temperature was 75℃ for the first hour, and the reaction temperature was uniformly raised to 80℃ from the second to the fourth hour. The reaction temperature was uniformly raised to 84℃ from the fifth to the eighth hour. After the reaction was completed, 24 parts by mass of the reaction terminator IRG-245 was injected to terminate the reaction. The residual monomer was removed by vacuum desorption, and then the product was centrifuged and dried to obtain the PVDC resin to be screened.

[0152] (6) Resin sieving: Use a 40-mesh sieve to remove resin particles that are too large from the PVDC resin to be sieved, and then use an 80-mesh sieve to remove resin particles that are too small, so as to obtain PVDC resin with uniform particle size.

[0153] The method for preparing functional breathable PVDC resin using the functional breathable PVDC resin composition of this embodiment as raw material includes the following steps: 1) Add ATBC and ESO to PVDC resin and mix at 65°C for 1 hour to obtain the first mixture.

[0154] 2) Add EVA powder, oxidized polyethylene wax, polyethylene wax, antioxidant 1010, antioxidant 1076 and amino acid modified polycarboxylate to the first mixture, and mix at 65°C for 2 hours to obtain the second mixture.

[0155] 3) Remove the agglomerated material from the second mixture using a 20-mesh sieve to obtain the finished resin.

[0156] Example 4 This embodiment provides a functional breathable PVDC resin composition, which consists of: 100 parts by weight of PVDC resin, 3 parts by weight of ESO, 2 parts by weight of ATBC, 4 parts by weight of EVA powder, 0.1 parts by weight of oxidized polyethylene wax, 0.4 parts by weight of polyethylene wax, 0.2 parts by weight of antioxidant 1010, 0.1 parts by weight of antioxidant 1076, and 5 parts by weight of amino acid modified polycarboxylate.

[0157] in: The EVA powder has a melt index of 8 g / 10 min at a temperature of 190℃ and a load of 2.16 kg, and a VA mass content of 30%.

[0158] The amino acid-modified polycarboxylate is a glutamic acid-modified carboxylate, with the following structural formula: In this system, R1 is an N-glutamic acid group, R2 is a C4 straight-chain alkylene group (i.e., -CH2CH2CH2CH2-), R3 is a C8 straight-chain alkylene group (i.e., -CH2(CH2)6CH2-), and M1 and M2 are both Ca. 2+ .

[0159] The PVDC resin in the functional breathable PVDC resin composition is prepared in-house, and its preparation method includes the following steps: (1) Prepare materials for use: Weigh 1304 parts by weight of deionized water, 1.4 parts by weight of hydroxypropyl cellulose, 0.8 parts by weight of sodium bicarbonate, 24 parts by weight of reaction terminator IRG-245, 3.5 parts by weight of tert-butyl peroxide, 900 parts by weight of VDC monomer, 30 parts by weight of AN monomer and 70 parts by weight of VC monomer.

[0160] (2) Prepare pH buffer solution and dispersant solution for later use: Weigh 1.4 parts by mass of hydroxypropyl cellulose and add 280 parts by mass of deionized water and mix well to obtain dispersant solution; Weigh 0.7 parts by mass of sodium bicarbonate and add 14 parts by mass of deionized water and mix well to obtain pH buffer solution.

[0161] (3) Prepare the mixed monomer and VC monomer: Mix 900 parts by mass of VDC monomer and 30 parts by mass of AN monomer evenly to obtain the mixed monomer; at the same time, prepare 70 parts by mass of VC monomer.

[0162] (4) Adding additives: First, replace with nitrogen and evacuate twice to reduce the pressure of the polymerization reactor to -0.098 MPa. Add VC monomer, then add mixed monomers and initiator tert-butyl peroxide. Stir at 50 rpm for 30 minutes. Then, add 1304 parts by mass of deionized water, pH buffer solution, dispersant solution and 50 parts by mass of rinsing water while stirring at 50 rpm. Disperse cold for 30 minutes to obtain the reaction solution.

[0163] (5) Resin synthesis: The reaction solution was stirred at 50 rpm for 8 hours. The reaction temperature was 74°C for the first hour, 79°C for the second to fourth hours, and 85°C for the fifth to eighth hours. After the reaction was completed, 24 parts by mass of the reaction terminator IRG-245 were added to terminate the reaction. The residual monomer was removed by vacuum desorption, and then the product was centrifuged and dried to obtain the PVDC resin to be screened.

[0164] (6) Resin sieving: Use a 40-mesh sieve to remove resin particles that are too large from the PVDC resin to be sieved, and then use an 80-mesh sieve to remove resin particles that are too small, so as to obtain PVDC resin with uniform particle size.

[0165] The method for preparing functional breathable PVDC resin using the functional breathable PVDC resin composition of this embodiment as raw material includes the following steps: 1) Add ATBC and ESO to PVDC resin and mix at 70°C for 1 hour to obtain the first mixture.

[0166] 2) Add EVA powder, oxidized polyethylene wax, polyethylene wax, antioxidant 1010, antioxidant 1076 and amino acid modified polycarboxylate to the first mixture, and mix at 70℃ for 2 hours to obtain the second mixture.

[0167] 3) Remove the agglomerated material from the second mixture using a 20-mesh sieve to obtain the finished resin.

[0168] Example 5 This embodiment provides a functional breathable PVDC resin composition, which comprises: 100 parts by weight of PVDC resin, 2.6 parts by weight of ESO, 1.6 parts by weight of ATBC, 3.5 parts by weight of EVA powder, 0.2 parts by weight of oxidized polyethylene wax, 0.3 parts by weight of polyethylene wax, 0.1 parts by weight of antioxidant 1010, 0.2 parts by weight of antioxidant 1076, and 4.8 parts by weight of amino acid modified polycarboxylate.

[0169] in: The EVA powder has a melt index of 7 g / 10 min and a VA content of 29% under the conditions of 190℃ and a load of 2.16 kg.

[0170] The amino acid-modified polycarboxylate is a glutamic acid-modified carboxylate, with the following structural formula: In this group, R1 is an N-glutamate group, R2 and R3 are both C8 straight-chain alkylene groups (i.e., -CH2(CH2)6CH2-), and M1 and M2 are both K-type alkylene groups. + .

[0171] The PVDC resin in the functional breathable PVDC resin composition is prepared in-house, and its preparation method includes the following steps: (1) Prepare materials for use: Weigh 1266 parts by weight of deionized water, 1.35 parts by weight of methyl cellulose ether, 0.7 parts by weight of sodium dihydrogen phosphate, 24 parts by weight of reaction terminator IRG-245, 3.4 parts by weight of tert-butyl peroxide-2-ethylhexanoate, 880 parts by weight of VDC monomer, 60 parts by weight of AN monomer and 60 parts by weight of MMA monomer.

[0172] (2) Prepare pH buffer solution and dispersant solution for later use: Weigh 1.35 parts by mass of methylcellulose ether and add 270 parts by mass of deionized water and mix well to obtain dispersant solution; Weigh 0.7 parts by mass of sodium pyrophosphate and add 14 parts by mass of deionized water and mix well to obtain pH buffer solution.

[0173] (3) Preparation of mixed monomers: Mix 880 parts by mass of VDC monomer, 60 parts by mass of AN monomer and 60 parts by mass of MMA monomer evenly to obtain mixed monomers.

[0174] (4) Adding additives: First, replace with nitrogen and evacuate twice to reduce the pressure of the polymerization reactor to -0.096 MPa. Add mixed monomers and initiator tert-butyl peroxide-2-ethylhexanoate and stir at 43 rpm for 26 minutes. Then, while stirring at 43 rpm, add 1266 parts by mass of deionized water, pH buffer solution, dispersant solution and 50 parts by mass of rinsing water. Disperse cold for 26 minutes to obtain the reaction solution.

[0175] (5) Resin synthesis: The reaction solution was stirred at 43 rpm for 8 hours. The reaction temperature was 74°C for the first hour, 78°C for the second to fourth hours, and 83°C for the fifth to eighth hours. After the reaction was completed, 24 parts by mass of the reaction terminator IRG-245 were added to terminate the reaction. The residual monomer was removed by vacuum desorption, and then the product was centrifuged and dried to obtain the PVDC resin to be screened.

[0176] (6) Resin sieving: Use a 40-mesh sieve to remove resin particles that are too large from the PVDC resin to be sieved, and then use an 80-mesh sieve to remove resin particles that are too small, so as to obtain PVDC resin with uniform particle size.

[0177] The method for preparing functional breathable PVDC resin using the functional breathable PVDC resin composition of this embodiment as raw material includes the following steps: 1) Add ATBC and ESO to PVDC resin and mix at 65°C for 1 hour to obtain the first mixture.

[0178] 2) Add EVA powder, oxidized polyethylene wax, polyethylene wax, antioxidant 1010, antioxidant 1076 and amino acid modified polycarboxylate to the first mixture, and mix at 65℃ for 2 hours to obtain the second mixture.

[0179] 3) Remove the agglomerated material from the second mixture using a 20-mesh sieve to obtain the finished resin.

[0180] Example 6 This embodiment is basically the same as embodiment 2, except that: In the functional breathable PVDC resin composition, the amino acid-modified polycarboxylate is a methionine-modified carboxylate with the following structural formula: In this compound, R1 is an N-methionine group, R2 is a C5 straight-chain alkylene group (i.e., -CH2(CH2)3CH2-), R3 is a C9 straight-chain alkylene group (i.e., -CH2(CH2)7CH2-), and M1 and M2 are both K. + .

[0181] Example 7 This embodiment is basically the same as embodiment 2, except that: In the functional breathable PVDC resin composition, the amino acid modified polycarboxylate is a mixture of phenylalanine modified carboxylate and lysine modified carboxylate in a mass ratio of 1:1.

[0182] in, The structural formula of phenylalanine modified carboxylate is: In this compound, R1 is an N-phenylalanine group, R2 is a C5 straight-chain alkylene group (i.e., -CH2(CH2)3CH2-), R3 is a C9 straight-chain alkylene group (i.e., -CH2(CH2)7CH2-), and M1 and M2 are both K. + ; The structural formula of lysine modified carboxylate is: In this system, R1 is an N-lysine group, R2 is a C5 straight-chain alkylene group (i.e., -CH2(CH2)3CH2-), R3 is a C9 straight-chain alkylene group (i.e., -CH2(CH2)7CH2-), and M1 and M2 are Ca... 2+ .

[0183] Example 8 This embodiment is basically the same as embodiment 2, except that: In the functional breathable PVDC resin composition, the content of EVA powder is 5 parts by weight.

[0184] Comparative Example 1 This comparative example is basically the same as Example 2, except that: The functional breathable PVDC resin composition does not contain amino acid-modified polycarboxylate.

[0185] In the method for preparing modified PVDC resin using the functional breathable PVDC resin composition of this comparative example as raw material, step 2) does not add amino acid modified polycarboxylate.

[0186] Comparative Example 2 This comparative example is basically the same as Example 2, except that: In the functional breathable PVDC resin composition: In the structural formula of glutamic acid modified carboxylates: R2 is a C12 straight-chain alkylene group (i.e., -CH2(CH2)). 10 CH2-), R3 is a C12 straight-chain alkylene group (i.e., -CH2(CH2)). 10 CH2-); The content of amino acid-modified carboxylates is 4.8 parts by weight (i.e., -CH2(CH2)). 10 CH2-).

[0187] Comparative Example 3 This comparative example is basically the same as Example 2, except that: In the functional breathable PVDC resin composition: the EVA powder contains 35% VA by mass, and the melt index is 4 g / 10 min under the conditions of 190℃ and 2.16 kg load.

[0188] Comparative Example 4 The preparation method of the PVDC resin in this comparative example includes the following steps: (1) In a 100L stainless steel polymerization reactor (length-to-diameter ratio of 2:1, double-layer two-blade 45° inclined paddle), add 55kg deionized water, 4g disodium ethylenediaminetetraacetate, 55g methyl cellulose ether, 25g sodium pyrophosphate, 180g epoxidized linseed oil, 90g tert-butyl peroxide-2-ethylhexanoate, 15g dodecyl peroxide, 32.55kg vinylidene chloride, and 3.5kg methyl acrylate. After cold dispersion for 30 minutes, the temperature is rapidly increased to 65℃ under a stirring speed of 120rpm to start polymerization. (2) Stir and heat to 80℃ and 170 rpm at a speed of 12.5 rpm / h and 3.75℃ / h, then heat to 90℃ at a speed of 5℃ / h under a stirring speed of 170 rpm and keep the temperature constant for 7.5 h to terminate polymerization. Remove residual monomers under vacuum, cool to 55℃ to discharge, centrifuge and dry. (3) Add 50g stearamide, 50g oleamide, 0.62kg epoxy linseed oil and 3kg chlorinated polyethylene, and heat to 80℃ at a rate of 25℃ / h to mix and mature.

[0189] Comparative Example 5 The preparation method of the PVDC resin in this comparative example includes the following steps: A vinylidene chloride / methyl acrylate interpolymer resin containing 7.7 wt% methyl acrylate and 10 wt% epoxidized soybean oil (plasticizer) was blended with 2 wt% PLASTISTRENGTHTML1000 (acrylate polymer).

[0190] II. Performance Testing 1. Molecular weight and particle size The molecular weight and D50 particle size of the PVDC resins prepared in Examples 1-8 and Comparative Examples 1-4 (Examples 1-8 and Comparative Examples 1-3 are PVDC resins in functional breathable PVDC resin compositions, i.e., PVDC resins prepared in step (6)) were tested respectively, wherein: Molecular weight: Tested using a WaterS ACQUITY ultra-high performance gel permeation chromatograph (gel chromatography).

[0191] D50 particle size: measured using a Mastersizer 3000+ Ultra laser particle size analyzer (wet method).

[0192] The test results are shown in Table 1.

[0193] 2. Oxygen transmission rate and carbon dioxide transmission rate The functional breathable PVDC resins obtained in Examples 1-8 and Comparative Examples 1-3, and the PVDC resins prepared in Comparative Examples 4-5, were respectively fabricated into 5-layer co-extruded films with a PE / EVA / PVDC / EVA / PE structure using a multi-layer co-extrusion equipment (wherein, PE is polyethylene, and the 5-layer co-extruded film consists of a PE film with a thickness of 12 μm, an EVA film with a thickness of 13 μm, a PVDC film with a thickness of 5 μm, an EVA film with a thickness of 13 μm, and a PE film with a thickness of 12 μm stacked sequentially, with a total thickness of 55 μm). The processing temperature of the PVDC extruder was 125°C in the feeding zone, 145°C in the compression zone, 150°C in the homogenization zone, 150°C in the connector, 150°C in the flange, and 150°C in the PVDC layer die.

[0194] The oxygen and carbon dioxide permeability of each of the prepared 5-layer co-extruded membranes were tested separately. The test method was as follows: Oxygen permeability: Tested according to the method specified in GB / T 1038-2000 "Gas permeability test method for plastic films and sheets - differential pressure method".

[0195] Carbon dioxide permeability: Tested according to the method specified in GB / T 1038-2000 "Gas permeability test of plastic films and sheets - differential pressure method".

[0196] The test results are shown in Table 2.

[0197] Table 1. Particle size and molecular weight test

[0198] As shown in Table 1, the Mw / Mn values ​​of Examples 1-8 fluctuated within the range of 1.32-1.45, indicating a relatively uniform molecular weight distribution of the resin, with Mw / Mn significantly lower than that of Comparative Example 4 (2.39). The particle size distribution of Examples 1-8 ranged from 0.60-0.67, much lower than that of Comparative Example 4 (0.84), indicating a uniform resin particle distribution. This relatively uniform molecular weight and particle size distribution ensured good processing performance of the resin.

[0199] Table 2 Comparison of Gas Transmission Rate and Processing Performance

[0200] Note: In Table 2, the melt pressure test data is the data detected by the pressure sensor built into the blown film unit, and the pressure fluctuation value is the highest value measured during the blown film process minus the lowest value.

[0201] As can be seen from Table 2, the carbon dioxide transmission rate of Examples 1-8 is around 860 cm⁻¹. 3 / m 2 For samples with a CO2 / O2 transmission rate greater than 6, a low O2 transmission rate ratio was maintained while ensuring a high CO2 level, which is beneficial for the growth of anaerobic bacteria such as lactic acid bacteria. Simultaneously, it allows for the rapid removal of CO2 produced during fermentation, and the melt pressure fluctuation is relatively small. Comparative Examples 1 and 5 did not use amino acid-modified carboxylates, and their CO2 / O2 transmission rate ratios were 4.8 and 4.4, respectively. Comparative Example 2 used an amino acid-modified carboxylate with a longer carbon chain, resulting in a CO2 / O2 transmission rate ratio of 5.3, lower than the ratio of 6 or more in Examples 1-8. This is because Comparative Examples 1 and 5 did not add amino acid-modified carboxylates, resulting in poor solubilization. The amino acid-modified carboxylate added in Comparative Example 2 had an excessively long carbon chain, leading to excessive steric hindrance of the carboxyl and amino groups, and a weaker synergistic effect between the carboxyl and amino groups. Comparative Example 3 used EVA powder with a higher VA content, resulting in higher melt viscosity and excessively high melt pressure, which is not conducive to continuous resin processing. The CO2 permeability of Example 4 is too low to meet the application requirements of functional breathing; in addition, the CO2 permeability / O2 permeability ratio is 4.5, which is too small. This is because Comparative Example 4 is a high-barrier packaging resin solution and does not contain amino acid modified carboxylates.

[0202] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0203] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0204] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A functional breathable PVDC resin composition, characterized in that, Including PVDC resin and amino acid-modified polycarboxylate.

2. The functional breathable PVDC resin composition according to claim 1, characterized in that, The amino acid-modified polycarboxylate is a waxy substance; And / or, the amino acid-modified polycarboxylate comprises at least one of the compounds shown in Formula I: Formula I, in: R1-N- represents an amino acid group; R2 and R3 are each independently selected from C4-C12 straight-chain alkylene or C4-C12 branched alkylene, and the total number of carbon atoms in R2 and R3 is less than 18; M1 and M2 each independently include Na + K + or Ca 2+ .

3. The functional breathable PVDC resin composition according to claim 2, characterized in that, The amino acid group includes one of the following: lysine, tryptophan, phenylalanine, methionine, threonine, isoleucine, leucine, valine, alanine, aspartic acid, glutamic acid, arginine, and histidine.

4. The functional breathable PVDC resin composition according to any one of claims 1 to 3, characterized in that, The mass ratio of the PVDC resin to the amino acid-modified polycarboxylate is 100:(3-5).

5. The functional breathable PVDC resin composition according to any one of claims 1 to 3, characterized in that, The functional breathable PVDC resin composition further includes polyethylene wax and oxidized polyethylene wax, wherein the mass ratio of the polyethylene wax, the oxidized polyethylene wax and the PVDC resin is (0.1-0.4):(0.1-0.4):

100.

6. The functional breathable PVDC resin composition according to any one of claims 1 to 3, characterized in that, The functional breathable PVDC resin composition further includes at least one of a plasticizer, an ethylene-vinyl acetate copolymer, and an antioxidant.

7. The functional breathable PVDC resin composition according to claim 6, characterized in that, The plasticizer includes at least one of acetylated tributyl citrate and epoxidized soybean oil; And / or, the mass ratio of the plasticizer to the PVDC resin is (3-5):100; And / or, the ethylene-vinyl acetate copolymer has a melt index of 4-8 g / 10 min at a temperature of 190°C and a load of 2.16 kg, and the vinyl acetate content is 25-30% by mass; And / or, the mass ratio of the ethylene-vinyl acetate copolymer to the PVDC resin is (3-5):100; And / or, the antioxidant includes at least one of antioxidant 1010 and antioxidant 1076; And / or, the mass ratio of the antioxidant to the PVDC resin is (0.2-0.4):

100.

8. The functional breathable PVDC resin composition according to claim 7, characterized in that, The plasticizer is tributyl acetyl citrate and epoxidized soybean oil, and the mass ratio of tributyl acetyl citrate to epoxidized soybean oil is (1-2):(2-3). And / or, the antioxidant is antioxidant 1010 and antioxidant 1076, and the mass ratio of antioxidant 1010 to antioxidant 1076 is (0.1-0.2):(0.1-0.2).

9. The functional breathable PVDC resin composition according to any one of claims 1 to 3, characterized in that, The functional breathable PVDC resin composition includes PVDC resin, amino acid-modified polycarboxylate, polyethylene wax, oxidized polyethylene wax, plasticizer, ethylene-vinyl acetate copolymer, and antioxidant.

10. The functional breathable PVDC resin composition according to claim 1, characterized in that, The PVDC resin has a weight-average molecular weight (Mw) of 91,873-97,382 Daltons, a polydispersity index (Mw / Mn) of 1.32-1.45, and a D50 particle size of 261-292 μm.

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