A pvdc resin composition

Abstract

The application provides a PVDC resin composition, which comprises dichloroethylene monomers, a comonomer, a hydrophilic monomer, a polymerization emulsifier, a polymerization initiator, a residual emulsifier, and a residual initiator; the comonomer comprises at least one of an acrylate monomer and an acrylonitrile monomer; the polymerization emulsifier and the residual emulsifier each independently comprises at least one of a double-bond-containing alkyl succinate salt, a double-bond-containing polyoxyethylene ether salt, and a double-bond-containing polyoxypropylene ether salt. The PVDC resin composition of the application is used for PVDC resin preparation; the polymerization emulsifier is used in a monomer polymerization stage, can guarantee that the emulsifier has a good emulsification capacity for monomers, guarantees that emulsion polymerization is smoothly carried out, and can avoid damage to a PVDC molecular chain caused by a too long chain segment; the residual emulsifier is used in a residual removal stage, can remove VDC residues, and omits a post-processing procedure; and the hydrophilic monomer can improve the stability and solid content of the emulsion.

Description

Technical Field

[0001] This application relates to the field of chlorinated polymer resin technology, and more particularly to a PVDC resin composition that can be used as a raw material to prepare polyvinylidene chloride resin (PVDC resin) in chlorinated polymer resins. Background Technology

[0002] PVDC has a good molecular structure with good symmetry and high crystallinity. In addition, the chlorine atoms are hydrophobic and do not form hydrogen bonds. Oxygen and water molecules have difficulty moving in the molecule, which makes it have excellent oxygen and moisture barrier properties. Moreover, its oxygen barrier property is not affected by the humidity of the surrounding environment, so it is widely used in food and pharmaceutical packaging, industrial products and ammunition protection, and steel corrosion protection.

[0003] However, while the high crystallinity of PVDC resin provides good barrier properties, it also creates numerous crystalline regions, making it very stable and dense. Solvent molecules have difficulty penetrating and disrupting these crystalline regions, resulting in extremely poor solubility. Furthermore, the strong polarity of the C-Cl bond generates strong cohesive forces between the molecular chains. Ordinary organic solvents cannot provide sufficient energy to overcome this attraction and disperse the PVDC molecular chains into the solvent.

[0004] The related technology discloses a method for preparing PVDC resin for reverse printing film, including the following steps: 120-145 parts by weight of deionized water, 70-85 parts by weight of vinylidene chloride monomer, 15-30 parts by weight of vinyl chloride monomer, 0.1-0.5 parts by weight of initiator, 0.05-0.3 parts by weight of pH buffer adjuster, 0.05-0.15 parts by weight of dispersant, 0.5-1.85 parts by weight of plasticizer, 0.03-0.3 parts by weight of lubricant, and 0.5-2 parts by weight of acrylic resin are subjected to a polymerization reaction. After the reaction lasts for 38-48 hours, the polymerization reaction is terminated, residual monomers are removed under vacuum, the material is cooled, discharged, centrifuged, and dried. Plasticizer and lubricant are added to the dried material, and the mixture is mixed and matured at 60-70℃ to obtain the PVDC resin product for reverse printing film. This invention features a safe and simple process, a stable polymerization reaction, and no concentrated exothermic phenomena. The reverse printing packaging film prepared using the product of this invention has strong image layering, good brightness, and vibrant color. This invention patent has defects such as large resin particle size, large differences in monomer polymerization rate, uneven molecular chains, long dissolution time, and poor barrier performance. Summary of the Invention

[0005] In view of this, this application aims to provide a PVDC resin composition containing a polymerization emulsifier and a residue-reducing emulsifier, including alkyl succinate salts containing double bonds, polyoxyethylene ether salts containing double bonds, and polyoxypropylene ether salts containing double bonds, as well as hydrophilic monomers and special comonomers. When preparing PVDC resin, the polymerization emulsifier, used in the monomer polymerization stage, ensures good emulsification ability of the emulsifier, guaranteeing smooth emulsion polymerization, while avoiding damage to the PVDC molecular chain due to excessively long chain segments. The residue-reducing emulsifier, used in the residue-reducing stage, effectively removes VDC residue, resulting in a PVDC emulsion with low residue, eliminating the need for post-processing steps. Simultaneously, the hydrophilic monomers improve the stability of the emulsion, facilitating the acquisition of PVDC emulsions with higher solid content, thereby increasing the yield of PVDC resin. In addition, controlling the mass content of dichloroethylene monomer in the PVDC resin composition to be above 45% is beneficial to improving the regularity of PVDC chains in the PVDC resin prepared from the PVDC resin composition, thereby improving the barrier properties of the PVDC resin.

[0006] To achieve the above objectives, a first aspect of this application provides a PVDC resin composition comprising a dichloroethylene monomer, a comonomer, a hydrophilic monomer, a polymerization emulsifier, a polymerization initiator, a residue-reducing emulsifier, and a residue-reducing initiator; wherein the comonomer comprises at least one of acrylate monomers and acrylonitrile monomers; and wherein the polymerization emulsifier and the residue-reducing emulsifier each independently comprise at least one of an alkyl succinate salt containing a double bond, a polyoxyethylene ether salt containing a double bond, and a polyoxypropylene ether salt containing a double bond.

[0007] In some embodiments, the double-bonded polyoxypropylene ether salt comprises at least one of the compounds shown in Formula I: Formula I, In Formula I, R1 is a C1-C6 straight-chain alkylene group or a C1-C6 branched alkylene group, R2 is one of sulfate group, sulfonate group or phosphate group; n is the degree of polymerization, and the value of n is in the range of 2-6; the sum of the number of carbon atoms in R1 and 3n is less than or equal to 21.

[0008] In some embodiments, the double-bonded alkyl succinate salt comprises at least one of the compounds shown in Formula II: Formula II, In Formula II, R1 is a C1-C6 straight-chain alkylene or a C1-C6 branched alkylene, R2 and R3 are each independently one of H atom, C2-C8 straight-chain alkyl, or C2-C8 branched alkyl, R4 is one of phosphate group, sulfonate group or sulfate group, and the total number of carbon atoms of R1, R2 and R3 is less than or equal to 18.

[0009] In some embodiments, the double-bonded polyoxyethylene ether salt comprises at least one of the compounds shown in Formula III: Formula III, In Formula III, R1 is a straight-chain alkylene group of C1-C6 or a branched alkylene group of C1-C6, R2 is one of sulfate group, sulfonate group or phosphate group; n is the degree of polymerization, and the value of n is in the range of 2-8; the sum of the number of carbon atoms in R1 and 2n is less than or equal to 18.

[0010] In some embodiments, the mass ratio of the dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residue-reducing emulsifier, and residue-reducing initiator is (50.8208-51.6494): (3.3696-4.143): (0.11048-0.2762): (0.8286-1.04956): (0.159-1.10955): (0.026-0.029): (0.2-0.264).

[0011] In some embodiments, the acrylate monomer is a short-chain acrylate monomer; the acrylonitrile monomer is a short-chain acrylonitrile monomer.

[0012] In some embodiments, the short-chain acrylate monomers include at least one of methyl acrylate, methyl methacrylate, and ethyl acrylate.

[0013] In some embodiments, the short-chain acrylonitrile monomer includes at least one of acrylonitrile and methacrylonitrile.

[0014] In some embodiments, the hydrophilic monomer includes at least one of acrylic acid, methacrylic acid, and hydroxyethyl acrylate.

[0015] In some embodiments, the polymerization initiator comprises tert-butyl hydroperoxide and sodium thiosulfate, and the mass ratio of tert-butyl hydroperoxide to sodium thiosulfate is (0.084-0.1113):(0.075-0.99825).

[0016] In some embodiments, the residue removal initiator comprises tert-butyl hydroperoxide and sodium thiosulfate, and the mass ratio of tert-butyl hydroperoxide to sodium thiosulfate is (0.11-0.144):(0.09-0.12).

[0017] In some embodiments, the PVDC resin composition further includes water, wherein the mass ratio of water to the dichloroethylene monomer is (52-54):(50.8208-51.6494).

[0018] In some embodiments, when the PVDC resin composition further includes water, the dichloroethylene monomer in the PVDC resin composition has a mass content of 45% or more.

[0019] The PVDC resin composition described in this application can bring at least the following beneficial effects: 1. Using at least one of the following—alkyl succinate salts, polyoxyethylene ether salts, and polyoxypropylene ether salts with suitable chain segments containing double bonds—as a polymerization emulsifier in the monomer polymerization stage of PVDC resin preparation can ensure that the emulsifier has a good ability to emulsify monomers and ensure the smooth progress of emulsion polymerization, while avoiding damage to the PVDC molecular chain due to excessively long chain segments.

[0020] 2. Using at least one of the following—alkyl succinate salts, polyoxyethylene ether salts, and polyoxypropylene ether salts with suitable chain segments containing double bonds—as a residue-removing emulsifier, and applying it in a small amount during the residue removal stage of PVDC resin preparation, can effectively remove VDC residues, resulting in a PVDC emulsion with low residue, thus eliminating the need for post-treatment steps.

[0021] 3. The use of hydrophilic monomers in the PVDC resin composition for PVDC resin preparation can improve the stability of the emulsion, which is beneficial for obtaining PVDC emulsions with higher solid content, and thus can improve the yield of PVDC resin.

[0022] 4. Controlling the mass content of dichloroethylene monomer in the PVDC resin composition to above 45% is beneficial to improving the regularity of PVDC chains in the PVDC resin prepared from the PVDC resin composition, thereby improving the barrier properties of the PVDC resin.

[0023] 5. Using acrylate monomers and / or acrylonitrile monomers with suitable chain segments as comonomers for PVDC resin preparation can avoid the damage to the PVDC molecular chain caused by monomers with excessively long chain segments, resulting in PVDC polymers with good oxygen and moisture barrier properties, and an oxygen permeability of less than 6 cm⁻¹. 3 / m 2 .day, water vapor transmission rate less than 5g / m 2 .day.

[0024] 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

[0025] 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.

[0026] 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.

[0027] 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.

[0028] In this application, when the term "and / or" is used in a list containing two or more items, it means that any of the listed items can be used alone or in combination with any one or more of the listed items. For example, the expression "A and / or B" is intended to mean A or B or A and B, that is, to mean only A, only B, or a combination of A and B.

[0029] In this application, the term "sulfate base" refers to the formula -OSO3. - M + Group, wherein M + Metal ions or NH4 + Metal ions include, but are not limited to, Na+ + K + Or Li + wait.

[0030] In this application, the term "sulfonate group" is -SO3. - M + M + Metal ions or NH4 + Metal ions include, but are not limited to, Na+ + K + Or Li + wait.

[0031] In this application, the term "phosphate group" is -PO4³. - or -PO3² - M2 + M is a metallic element or NH4, and the metallic element includes, but is not limited to, Na, K or Li.

[0032] In this application, alkylene refers to a divalent group formed by removing one hydrogen atom from each end of an alkane.

[0033] The PVDC resin composition of this application includes dichloroethylene monomer (i.e., VDC monomer), comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residue-reducing emulsifier, and residue-reducing initiator; the comonomer includes at least one of acrylate monomers and acrylonitrile monomers; the polymerization emulsifier and the residue-reducing emulsifier each independently include at least one of alkyl succinate salt containing double bonds, polyoxyethylene ether salt containing double bonds, and polyoxypropylene ether salt containing double bonds.

[0034] This PVDC resin composition contains polymeric emulsifiers and residue-reducing emulsifiers, including double-bonded alkyl succinate salts, double-bonded polyoxyethylene ether salts, and double-bonded polyoxypropylene ether salts, as well as hydrophilic monomers and special comonomers. During the preparation of PVDC resin, the polymeric emulsifiers, used in the monomer polymerization stage, ensure good emulsification ability of the emulsifiers, guaranteeing smooth emulsion polymerization, while avoiding damage to the PVDC molecular chains due to excessively long chain segments. The residue-reducing emulsifiers, used in the residue-reduction stage, effectively remove residual VDC, resulting in a PVDC emulsion with low residue, eliminating the need for post-processing steps. Simultaneously, the hydrophilic monomers improve the stability of the emulsion, facilitating the acquisition of PVDC emulsions with higher solid content, thereby increasing the yield of PVDC resin. Furthermore, controlling the mass content of dichloroethylene monomer in the PVDC resin composition to be above 45% helps improve the regularity of the PVDC chains in the PVDC resin prepared from the PVDC resin composition, thus enhancing the barrier properties of the PVDC resin.

[0035] In some embodiments, the double-bonded polyoxypropylene ether salt includes, but is not limited to, at least one of the compounds represented by Formula I: Formula I, In Formula I, R1 is a C1-C6 straight-chain alkylene group or a C1-C6 branched alkylene group, R2 is one of sulfate group, sulfonate group or phosphate group; n is the degree of polymerization, and the value of n is in the range of 2-6; the sum of the number of carbon atoms in R1 and 3n is less than or equal to 21.

[0036] For example, in Formula I, the number of carbon atoms in R1 is 1, 2, 3, 4, 5, or 6. R1 includes, but is not limited to, -CH2-, -CH2CH2-, -CHCH3-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -C(CH3)2-, -C(CH3)CH2CH3-, -CH3CHCHCH3-, -CHCH(CH3)2-, -CHCH2CH(CH3)2-, -CHC(CH3)3-, -CHCH2CH2CH(CH3)2-, or -CHCH2C(CH3)3-, etc.

[0037] For example, the values ​​of n in Equation I include, but are not limited to, 3, 4, or 5.

[0038] In some embodiments, the double-bonded alkyl succinate salt includes, but is not limited to, at least one of the compounds represented by Formula II: Formula II, In Formula II, R1 is a C1-C6 straight-chain alkylene or a C1-C6 branched alkylene, R2 and R3 are each independently one of H atom, C2-C8 straight-chain alkyl, or C2-C8 branched alkyl, R4 is one of phosphate group, sulfonate group or sulfate group, and the total number of carbon atoms of R1, R2 and R3 is less than or equal to 18.

[0039] For example, in Formula II, R1 has 1, 2, 3, 4, 5 or 6 carbon atoms, R2 has 0, 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms, and R3 has 0, 1, 2, 3, 4, 5, 6, 7 or 8 carbon atoms.

[0040] For example, R1 in Formula II includes, but is not limited to, -CH2-, -CH2CH2-, -CHCH3-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -C(CH3)2-, -C(CH3)CH2CH3-, -CH3CHCHCH3-, -CHCH(CH3)2-, -CHCH2CH(CH3)2-, -CHC(CH3)3-, -CHCH2CH2CH(CH3)2-, or -CHCH2C(CH3)3-, etc.

[0041] For example, in R2 and R3 of Formula II, the C2-C8 straight-chain alkyl groups include, but are not limited to, methyl (-CH3), ethyl (-CH2CH3 or -C2H5), propyl (-CH2CH2CH3), butyl (-CH2CH2CH2CH3), pentyl (-CH2CH2CH2CH2CH3), or hexyl (-CH2CH2CH2CH2CH2CH3), etc., and the C2-C8 branched alkyl groups include, but are not limited to, isopropyl... Butyl (-CH(CH3)2), sec-butyl (-CH(CH3)CH2CH3 or CH3CH2CH(CH3)), isobutyl (-CH2CH(CH3)2), tert-butyl (-C(CH3)3), isopentyl (-CH2CH2CH(CH3)2), neopentyl (-CH2C(CH3)3), isohexyl (-CH2CH2CH2CH(CH3)2) or neohexyl (-CH2CH2C(CH3)3), etc.

[0042] In some embodiments, the double-bonded polyoxyethylene ether salt includes, but is not limited to, at least one of the compounds represented by Formula III: Formula III, In Formula III, R1 is a straight-chain alkylene group of C1-C6 or a branched alkylene group of C1-C6, R2 is one of sulfate group, sulfonate group or phosphate group; n is the degree of polymerization, and the value of n is in the range of 2-8; the sum of the number of carbon atoms in R1 and 2n is less than or equal to 18.

[0043] For example, in Formula III, R1 has 1, 2, 3, 4, 5 or 6 carbon atoms, and R1 includes, but is not limited to, -CH2-, -CH2CH2-, -CHCH3-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -C(CH3)2-, -C(CH3)CH2CH3-, -CH3CHCHCH3-, -CHCH(CH3)2-, -CHCH2CH(CH3)2-, -CHC(CH3)3-, -CHCH2CH2CH(CH3)2- or -CHCH2C(CH3)3-, etc.

[0044] For example, the values ​​of n in Equation III include, but are not limited to, 3, 4, 5, 6, or 7.

[0045] It should be noted that, in the embodiments of this application, the compounds shown in Formula I, Formula II and Formula III can all be prepared by existing organic synthesis methods or obtained commercially.

[0046] In some embodiments, the mass ratio of the dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residue-reducing emulsifier, and residue-reducing initiator is (50.8208-51.6494): (3.3696-4.143): (0.11048-0.2762): (0.8286-1.04956): (0.159-1.10955): (0.026-0.029): (0.2-0.264).

[0047] Based on the above mass ratios of dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residue-reducing emulsifier, and residue-reducing initiator, it can be understood that: The PVDC resin composition contains: 50.8208-51.6494 parts by weight of dichloroethylene monomer, 3.3696-4.143 parts by weight of comonomer, 0.11048-0.2762 parts by weight of hydrophilic monomer, 0.8286-1.04956 parts by weight of polymerization emulsifier, 0.159-1.10955 parts by weight of polymerization initiator, 0.026-0.029 parts by weight of residue-reducing emulsifier, and 0.2-0.264 parts by weight of residue-reducing initiator.

[0048] For example, in the PVDC resin composition: the content of dichloroethylene monomer includes, but is not limited to, 50.9 parts by weight, 51 parts by weight, 51.1 parts by weight, 51.2 parts by weight, 51.3 parts by weight, 51.4 parts by weight, 51.5 parts by weight, or 51.6 parts by weight; the content of comonomer includes, but is not limited to, 3.7 parts by weight, 3.8 parts by weight, 3.9 parts by weight, or 4 parts by weight; the content of hydrophilic monomer includes, but is not limited to, 0.13 parts by weight, 0.15 parts by weight, 0.17 parts by weight, 0.19 parts by weight, 0.21 parts by weight, 0.23 parts by weight, or 0.25 parts by weight; and the content of polymerization emulsifier includes, but is not limited to, […]. The amounts of polymerization initiator are included in the following quantities: 0.84 parts by weight, 0.86 parts by weight, 0.88 parts by weight, 1 part by weight, 1.12 parts by weight, 1.14 parts by weight, 1.16 parts by weight, or 1.18 parts by weight, etc. The amounts of polymerization initiator are included in the following quantities: 0.2 parts by weight, 0.4 parts by weight, 0.6 parts by weight, 0.8 parts by weight, or 1 part by weight, etc. The amounts of residual emulsifier are included in the following quantities: 0.0265 parts by weight, 0.027 parts by weight, 0.0275 parts by weight, or 0.028 parts by weight, etc. The amounts of residual initiator are included in the following quantities: 0.21 parts by weight, 0.22 parts by weight, 0.23 parts by weight, 0.24 parts by weight, or 0.25 parts by weight, etc.

[0049] At this point, the ratio of the contents of the above-mentioned dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residual emulsifier, and residual initiator in the PVDC resin composition is the mass ratio of dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residual emulsifier, and residual initiator.

[0050] In some embodiments, the polymerization initiator includes, but is not limited to, tert-butyl hydroperoxide (TBHP) and sodium formaldehyde sulfoxylate (SFS). Sodium formaldehyde sulfoxylate is also known as sodium formaldehyde sulfoxylate.

[0051] In some embodiments, the mass ratio of tert-butyl hydroperoxide to sodium thiosulfate in the polymerization initiator is (0.084-0.1113):(0.075-0.99825), including but not limited to 0.9:0.8, 0.9:0.9, 0.9:0.95, 1:0.8, 1:0.9, 1:0.95, 0.11:0.8, 0.11:0.9, or 0.11:0.95.

[0052] In some embodiments, the residue-eliminating initiator includes tert-butyl hydroperoxide (TBHP) and sodium thiosulfate (SFS).

[0053] In some embodiments, the mass ratio of tert-butyl hydroperoxide to sodium thiosulfate in the residue-removing initiator is (0.11-0.144):(0.09-0.12), including but not limited to 0.12:0.1, 0.12:0.11, 0.13:0.1, 0.13:0.11, 0.14:0.1, or 0.14:0.11.

[0054] As an optional example, the PVDC resin composition contains: 50.8208-51.6494 parts by weight of dichloroethylene monomer, 3.3696-4.143 parts by weight of comonomer, 0.11048-0.2762 parts by weight of hydrophilic monomer, 0.8286-1.04956 parts by weight of polymerization emulsifier, 0.159-1.10955 parts by weight of polymerization initiator (of which, 0.084-0.1113 parts by weight of TBHP and 0.075-0.99825 parts by weight of SFS), 0.026-0.029 parts by weight of residue-reducing emulsifier, and 0.2-0.264 parts by weight of residue-reducing initiator (of which, 0.11-0.144 parts by weight of TBHP and 0.09-0.12 parts by weight of SFS).

[0055] In some embodiments, the PVDC resin composition further includes water, wherein the mass ratio of water to the dichloroethylene monomer is (52-54):(50.8208-51.6494). The water includes, but is not limited to, deionized water, pure water, and ultrapure water.

[0056] In some embodiments, when the PVDC resin composition further includes water, the dichloroethylene monomer in the PVDC resin composition has a mass content of 45% or more.

[0057] In some embodiments, when the PVDC resin composition further includes water, the mass content of the dichloroethylene monomer in the PVDC resin composition includes, but is not limited to, 46% or more, 47% or more, 48% or more, 49% or more, or 50% or more, and may be 45-48%.

[0058] Based on the above mass ratios of dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residue-reducing emulsifier, and residue-reducing initiator, it can be understood that: The PVDC resin composition contains: 50.8208-51.6494 parts by weight of dichloroethylene monomer, 3.3696-4.143 parts by weight of comonomer, 0.11048-0.2762 parts by weight of hydrophilic monomer, 0.8286-1.04956 parts by weight of polymerization emulsifier, 0.159-1.10955 parts by weight of polymerization initiator, 0.026-0.029 parts by weight of residue-reducing emulsifier, 0.2-0.264 parts by weight of residue-reducing initiator, and 52-54 parts by weight of water.

[0059] For example, in the PVDC resin composition, the water content includes, but is not limited to, 52.5 parts by weight, 53 parts by weight, or 53.5 parts by weight. In this case, the ratio of any water content to the dichloroethylene monomer content in the aforementioned PVDC resin composition is the mass ratio of water to dichloroethylene monomer.

[0060] As an optional example, the PVDC resin composition comprises: 50.8208-51.6494 parts by weight of dichloroethylene monomer, 3.3696-4.143 parts by weight of comonomer, 0.11048-0.2762 parts by weight of hydrophilic monomer, 0.8286-1.04956 parts by weight of polymerization emulsifier, 0.159-1.10955 parts by weight of polymerization initiator (including 0.084-0.1113 parts by weight of TBHP and 0.075-0.99825 parts by weight of SFS), 0.026-0.029 parts by weight of residual emulsifier, 0.2-0.264 parts by weight of residual initiator (including 0.11-0.144 parts by weight of TBHP and 0.09-0.12 parts by weight of SFS), and 52-54 parts by weight of water.

[0061] In the embodiments of this application, 0.026-0.029 parts by weight of residual emulsifier are used in the residual removal stage of PVDC resin preparation, which can better improve the stability of the emulsion, prepare PVDC emulsion with higher solid content, and thus improve the yield of PVDC resin.

[0062] In some embodiments, the acrylate monomer is a short-chain acrylate monomer; the acrylonitrile monomer is a short-chain acrylonitrile monomer.

[0063] In the embodiments of this application, the comonomers are selected from acrylate monomers and / or acrylonitrile monomers with short carbon chains. When the PVDC resin composition is used in the preparation of PVDC resin, the damage to the PVDC molecular chain caused by monomers with excessively long chains can be avoided, resulting in a PVDC polymer with good oxygen and moisture barrier properties, and an oxygen permeability of less than 6 cm⁻¹. 3 / m 2 .day, water vapor transmission rate less than 5g / m 2 .day.

[0064] For example, the short-chain acrylate monomers include, but are not limited to, at least one of methyl acrylate (MA), methyl methacrylate (MMA), ethyl acrylate (EA), etc.

[0065] For example, the short-chain acrylonitrile monomer includes, but is not limited to, at least one of acrylonitrile (AN), methacrylonitrile (MAN), etc.

[0066] In some embodiments, the hydrophilic monomer includes, but is not limited to, at least one of acrylic acid (AA), methacrylic acid (MAA), and hydroxyethyl acrylate (HEA).

[0067] It should be noted that the PVDC resin composition of this application contains 0.11048-0.2762 parts by mass of hydrophilic monomers, which are used in the preparation of PVDC resin. This can improve the stability of the emulsion, which is beneficial to obtaining a PVDC emulsion with a higher solid content, and thus can improve the yield of PVDC resin.

[0068] In some embodiments, the method for preparing PVDC resin using the PVDC resin composition of the present application as a reactant includes the following steps: 1. Prepare the reaction raw materials for later use. The composition of the reaction raw materials is as follows: VDC monomer: 50.8208-51.6494 parts by weight Comonomer: 3.3696-4.143 parts by weight Hydrophilic monomer: 0.11048-0.2762 parts by weight Polymerizing emulsifier: 0.8286-1.04956 parts by weight Polymerization initiator TBHP: 0.084-0.1113 parts by weight Polymerization initiator SFS: 0.075-0.99825 parts by weight Residue-removing initiator TBHP: 0.11-0.144 parts by weight SFS (Sterile Initiator for Residue Elimination): 0.09-0.12 parts by weight Residual emulsifier: 0.026-0.029 parts by weight 52-54 parts by weight of water.

[0069] 2. Prepare the mixed monomers: Mix the prepared VDC monomers, comonomers and hydrophilic monomers evenly to obtain the mixed monomers.

[0070] 3. Prepare the polymer emulsifier aqueous solution: Mix the prepared polymer emulsifier with 5 parts by mass of water to obtain the polymer emulsifier aqueous solution.

[0071] 4. Prepare the polymerization initiator aqueous solution: Mix the polymerization initiator TBHP with 5 parts by mass of water to obtain polymerization initiator aqueous solution A; mix the polymerization initiator SFS with 5 parts by mass of water to obtain polymerization initiator aqueous solution B.

[0072] 5. Prepare the residue removal agent aqueous solution: Mix the residue removal initiator TBHP with 2 parts by mass of water to obtain residue removal agent aqueous solution A; mix the residue removal initiator SFS and residue removal emulsifier with 2 parts by mass of water to obtain residue removal agent aqueous solution B.

[0073] 6. Seed polymerization: Add 33-35 parts by weight of water and part of the polymerization emulsifier aqueous solution to the polymerization reactor, evacuate to -0.095 to -0.098 MPa, quickly pump in part of the mixed monomers using a monomer pump, rapidly heat to 50-65℃, then pump in part of the initiator aqueous solution A and part of the polymerization initiator aqueous solution B, maintain the temperature at 50-65℃ and the stirring speed at 50-80 rpm, and complete the polymerization within 0.5-1.5 hours.

[0074] 7. Addition polymerization: The remaining aqueous solution of polymerization emulsifier, the remaining mixed monomers, the remaining aqueous solution of polymerization initiator A and the remaining aqueous solution of polymerization initiator B are fed into the polymerization reactor at a constant speed over 8-12 hours, maintaining a rotation speed of 50-80 rpm and a reaction temperature of 50-65℃.

[0075] 8. Residue Removal: Quickly add the residue removal agent aqueous solution A and residue removal agent aqueous solution B prepared in step 5 into the polymerization reactor, keep warm for 0.5-1h, and obtain the emulsion.

[0076] 9. Spray drying: Cool the emulsion obtained in step 8 to 20-30℃, filter it with a 300-mesh filter, and dry it by spray drying to obtain the finished resin.

[0077] The inlet air temperature of the spray dryer is controlled at 180-220℃, including but not limited to 190℃, 200℃ or 210℃; the outlet air temperature of the spray dryer is controlled at 70-95℃, including but not limited to 75℃, 80℃, 85℃ or 90℃.

[0078] It should be noted that in step 6 above, the mass ratio of partial polymerization initiator aqueous solution A to polymerization initiator aqueous solution A and the mass ratio of partial polymerization initiator aqueous solution B to polymerization initiator aqueous solution B can be the same or different, but it is preferred that they are the same.

[0079] The above-described method for preparing PVDC resin employs emulsion copolymerization, which allows for relatively uniform polymerization of the PVDC polymer. This avoids overly dense local crystalline regions caused by differences in monomer reactivity ratios. Furthermore, through formulation optimization, the molecular weight is appropriately moderate, ensuring good resin solubility. Simultaneously, this method utilizes soap-free polymerization combined with spray drying, eliminating the need for demulsification and washing. This simplifies the preparation process and makes it environmentally friendly. The resulting PVDC resin exhibits small particle size, high specific surface area, and rapid dissolution rate.

[0080] In summary, the PVDC resin prepared by the above method using the PVDC resin composition of the present application as the reaction raw material has at least excellent solubility and barrier properties, and good adhesion.

[0081] The following non-limiting embodiments further illustrate certain features of the present technology.

[0082] I. Examples and Comparative Examples In the following examples and comparative examples, parts by mass are used, where 1 part by mass represents 1 kg.

[0083] Unless otherwise specified, all reagents used in the following examples and comparative examples can be synthesized by conventional methods or obtained commercially.

[0084] Example 1 This embodiment provides a PVDC resin composition, the composition of which is as follows: VDC monomer: 50.8208 parts by weight Comonomer: 4.143 parts by weight Hydrophilic monomer: 0.2762 parts by weight Polymerizing emulsifier: 0.8286 parts by weight Polymerization initiator: 0.159 parts by weight Residue-removing initiator: 0.22 parts by weight Eliminating emulsifier: 0.026 parts by weight Water: 53 parts by weight; in, The comonomer consists of 1.6572 parts by mass of methacrylic acid (MAA) and 2.4858 parts by mass of acrylonitrile (AN); The hydrophilic monomer is acrylic acid (AA); Both the polymerization emulsifier and the residue-eliminating emulsifier are alkyl succinate salts containing double bonds, specifically ammonium sulfate alkyl succinate containing double bond groups, with the following structural formula: Where R1 is a C4 straight-chain alkylene group -CH2CH2CH2CH2-, R2 is a C6 straight-chain alkyl group -CH2CH2CH2CH2CH2CH3, R3 is a C3 straight-chain alkyl group -CH2CH2CH3, and R4 is -OSO3. - NH4 + ; The polymerization initiator consists of 0.084 parts by mass of tert-butyl hydroperoxide (TBHP) and 0.075 parts by mass of sodium thiosulfate (SFS); The residue-eliminating initiator consists of 0.12 parts by weight of tert-butyl hydroperoxide (TBHP) and 0.1 parts by weight of sodium thiosulfate (SFS); The water is deionized.

[0085] A method for preparing PVDC resin using the PVDC resin composition as a reactant includes the following steps: (1) Preparation of mixed monomers: Mix VDC monomers, comonomers and hydrophilic monomers evenly to obtain mixed monomers.

[0086] (2) Prepare an aqueous solution of polymer emulsifier: Mix the polymer emulsifier with 5 parts by mass of water to obtain an aqueous solution of polymer emulsifier.

[0087] (3) Prepare the polymerization initiator aqueous solution: Mix TBHP in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution A; mix SFS in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution B.

[0088] (4) Prepare the residue removal agent aqueous solution: Mix TBHP in the residue removal initiator with 2 parts by mass of water to obtain residue removal agent aqueous solution A; mix SFS in the residue removal initiator and residue removal emulsifier with 2 parts by mass of water to obtain residue removal agent aqueous solution B.

[0089] (5) Seed polymerization: Add 34 parts by mass of water and 10% by mass of polymerization emulsifier aqueous solution to the polymerization reactor, evacuate to -0.095 MPa, and quickly pump in 10% by mass of mixed monomers using a monomer pump. After rapidly heating to 50°C, pump in 20% by mass of polymerization initiator aqueous solution A and 20% by mass of polymerization initiator aqueous solution B. Maintain the temperature at 50°C and the stirring speed at 50 rpm, and complete the polymerization within 0.5 h.

[0090] (6) Addition polymerization: The remaining 90% of the total mass of the polymerization emulsifier aqueous solution, the remaining 90% of the total mass of the mixed monomers, the remaining 80% of the total mass of the polymerization initiator aqueous solution A, and the remaining 80% of the total mass of the polymerization initiator aqueous solution B are fed into the polymerization reactor at a constant speed over 8 hours, maintaining a rotation speed of 50 rpm and a reaction temperature of 50℃.

[0091] (7) Residue removal: Quickly add the residue removal agent aqueous solution A and residue removal agent aqueous solution B prepared in step (4) into the polymerization kettle, keep warm for 0.5h, and obtain emulsion.

[0092] (8) Spray drying: Cool the emulsion obtained in step (7) to 20°C, filter it with a 300-mesh filter, and dry it by spray drying to obtain the finished resin.

[0093] The inlet air temperature of the spray dryer is controlled at 180℃, and the outlet air temperature of the spray dryer is controlled at 70℃.

[0094] Example 2 This embodiment provides a PVDC resin composition, the composition of which is as follows: VDC monomer: 51.097 parts by weight Comonomer: 4.0325 parts by weight Hydrophilic monomer: 0.11048 parts by weight Polymerizing emulsifier: 0.8838 parts by weight Polymerization initiator: 0.1745 parts by weight Residue-removing initiator: 0.242 parts by weight Residual emulsifier: 0.027 parts by weight Water: 54 parts by weight; in, The comonomer consists of 1.6572 parts by mass of methyl acrylate (MA) and 2.3753 parts by mass of acrylonitrile (AN); The hydrophilic monomer is acrylic acid (AA); Both the polymerization emulsifier and the residue-eliminating emulsifier are polyoxyethylene ether salts containing double bonds, specifically sodium polyoxyethylene ether sulfate containing double bonds, with the structural formula as follows: R1 is a C3 straight-chain alkylene group -CH2CH2CH2-, and R2 is -OSO3. - Na + n is the degree of aggregation, n=5; The polymerization initiator consists of 0.092 parts by mass of tert-butyl hydroperoxide (TBHP) and 0.0825 parts by mass of sodium thiosulfate (SFS); The residue-eliminating initiator consists of 0.132 parts by weight of tert-butyl hydroperoxide (TBHP) and 0.11 parts by weight of sodium thiosulfate (SFS); The water is deionized.

[0095] A method for preparing PVDC resin using the PVDC resin composition as a reactant includes the following steps: (1) Preparation of mixed monomers: Mix VDC monomers, comonomers and hydrophilic monomers evenly to obtain mixed monomers.

[0096] (2) Prepare an aqueous solution of polymer emulsifier: Mix the polymer emulsifier with 5 parts by mass of water to obtain an aqueous solution of polymer emulsifier.

[0097] (3) Prepare the polymerization initiator aqueous solution: Mix TBHP in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution A; mix SFS in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution B.

[0098] (4) Prepare the residue removal agent aqueous solution: Mix TBHP in the residue removal initiator with 2 parts by mass of water to obtain residue removal agent aqueous solution A; mix SFS in the residue removal initiator and residue removal emulsifier with 2 parts by mass of water to obtain residue removal agent aqueous solution B.

[0099] (5) Seed polymerization: Add 35 parts by mass of water and 10% by mass of polymerization emulsifier aqueous solution to the polymerization reactor, evacuate to -0.096 MPa, and quickly pump in 10% by mass of mixed monomers using a monomer pump. After rapidly heating to 55°C, pump in 20% by mass of polymerization initiator aqueous solution A and 20% by mass of polymerization initiator aqueous solution B. Maintain the temperature at 55°C and the stirring speed at 55 rpm, and complete the polymerization within 1 hour.

[0100] (6) Addition polymerization: The remaining 90% of the total mass of the polymerization emulsifier aqueous solution, the remaining 90% of the total mass of the mixed monomers, the remaining 80% of the total mass of the polymerization initiator aqueous solution A, and the remaining 80% of the total mass of the polymerization initiator aqueous solution B are fed into the polymerization reactor at a constant speed over 8 hours, maintaining a rotation speed of 55 rpm and a reaction temperature of 55℃.

[0101] (7) Residue removal: Quickly add the residue removal agent aqueous solution A and residue removal agent aqueous solution B prepared in step (4) into the polymerization kettle, keep warm for 1 hour, and obtain emulsion.

[0102] (8) Spray drying: Cool the emulsion obtained in step (7) to 25°C, filter it with a 300-mesh filter, and dry it by spray drying to obtain the finished resin.

[0103] The inlet air temperature of the spray dryer is controlled at 185℃, and the outlet air temperature of the spray dryer is controlled at 75℃.

[0104] Example 3 This embodiment provides a PVDC resin composition, the composition of which is as follows: VDC monomer: 51.3732 parts by weight Comonomer: 3.701 parts by weight Hydrophilic monomer: 0.16572 parts by weight Polymerizing emulsifier: 0.9391 parts by weight Polymerization initiator: 1.0087 parts by weight Residue-removing initiator: 0.20 parts by weight Residual emulsifier: 0.027 parts by weight Water: 52 parts by weight; in, The comonomer consists of 1.9334 parts by mass of methyl acrylate (MA) and 1.7676 parts by mass of acrylonitrile (AN); The hydrophilic monomer is acrylic acid (AA); Both the polymerization emulsifier and the residue-eliminating emulsifier are polyoxyethylene ether salts containing double bonds, specifically ammonium polyoxyethylene ether sulfonate containing double bonds, with the structural formula as follows: R1 is a C3 straight-chain alkylene group -CH2CH2CH2-, and R2 is -SO3 - NH4 + n is the degree of aggregation, n=6; The polymerization initiator consists of 0.1012 parts by mass of tert-butyl hydroperoxide (TBHP) and 0.9075 parts by mass of sodium silicate (SFS); The residue-eliminating initiator consists of 0.11 parts by weight of tert-butyl hydroperoxide (TBHP) and 0.09 parts by weight of sodium thiosulfate (SFS); The water is deionized.

[0105] A method for preparing PVDC resin using the PVDC resin composition as a reactant includes the following steps: (1) Preparation of mixed monomers: Mix VDC monomers, comonomers and hydrophilic monomers evenly to obtain mixed monomers.

[0106] (2) Prepare an aqueous solution of polymer emulsifier: Mix the polymer emulsifier with 5 parts by mass of water to obtain an aqueous solution of polymer emulsifier.

[0107] (3) Prepare the polymerization initiator aqueous solution: Mix TBHP in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution A; mix SFS in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution B.

[0108] (4) Prepare the residue removal agent aqueous solution: Mix TBHP in the residue removal initiator with 2 parts by mass of water to obtain residue removal agent aqueous solution A; mix SFS in the residue removal initiator and residue removal emulsifier with 2 parts by mass of water to obtain residue removal agent aqueous solution B.

[0109] (5) Seed polymerization: Add 33 parts by mass of water and 10% by mass of polymerization emulsifier aqueous solution to the polymerization reactor, evacuate to -0.097 MPa, and quickly pump in 10% by mass of mixed monomers using a monomer pump. After rapidly heating to 60°C, pump in 20% by mass of polymerization initiator aqueous solution A and 20% by mass of polymerization initiator aqueous solution B. Maintain the temperature at 60°C and the stirring speed at 60 rpm, and complete the polymerization within 1 hour.

[0110] (6) Addition polymerization: The remaining 90% of the total mass of the polymerization emulsifier aqueous solution, the remaining 90% of the total mass of the mixed monomers, the remaining 80% of the total mass of the polymerization initiator aqueous solution A, and the remaining 80% of the total mass of the polymerization initiator aqueous solution B are fed into the polymerization reactor at a constant speed within 10 hours, maintaining a rotation speed of 60 rpm and a reaction temperature of 60℃.

[0111] (7) Residue removal: Quickly add the residue removal agent aqueous solution A and residue removal agent aqueous solution B prepared in step (4) into the polymerization kettle, keep warm for 1 hour, and obtain emulsion.

[0112] (8) Spray drying: Cool the emulsion obtained in step (7) to 30°C, filter it with a 300-mesh filter, and dry it by spray drying to obtain the finished resin.

[0113] The inlet air temperature of the spray dryer is controlled at 190℃, and the outlet air temperature of the spray dryer is controlled at 80℃.

[0114] Example 4 This embodiment provides a PVDC resin composition, the composition of which is as follows: VDC monomer: 51.6494 parts by weight Comonomer: 3.3696 parts by weight Hydrophilic monomer: 0.22096 parts by weight Polymerizing emulsifier: 0.9943 parts by weight Polymerization initiator: 1.1095 parts by weight Residue-removing initiator: 0.264 parts by weight Eliminating emulsifier: 0.028 parts by weight Water: 52.5 parts by weight; in, The comonomer consists of 1.6572 parts by mass of methyl acrylate (MA) and 1.7124 parts by mass of acrylonitrile (AN); The hydrophilic monomer is methacrylic acid (MAA); Both the polymerization emulsifier and the residue-eliminating emulsifier are polyoxyethylene ether salts containing double bonds, specifically sodium polyoxyethylene ether sulfonate containing double bonds, with the structural formula as follows: R1 is a C4 straight-chain alkylene group -CH2CH2CH2CH2-, and R2 is -SO3 - Na + n is the degree of aggregation, n=5; The polymerization initiator consists of 0.1113 parts by mass of tert-butyl hydroperoxide (TBHP) and 0.9982 parts by mass of sodium silicate (SFS); The residue-eliminating initiator consists of 0.144 parts by weight of tert-butyl hydroperoxide (TBHP) and 0.12 parts by weight of sodium thiosulfate (SFS); The water is deionized.

[0115] A method for preparing PVDC resin using the PVDC resin composition as a reactant includes the following steps: (1) Preparation of mixed monomers: Mix VDC monomers, comonomers and hydrophilic monomers evenly to obtain mixed monomers.

[0116] (2) Prepare an aqueous solution of polymer emulsifier: Mix the polymer emulsifier with 5 parts by mass of water to obtain an aqueous solution of polymer emulsifier.

[0117] (3) Prepare the polymerization initiator aqueous solution: Mix TBHP in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution A; mix SFS in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution B.

[0118] (4) Prepare the residue removal agent aqueous solution: Mix TBHP in the residue removal initiator with 2 parts by mass of water to obtain residue removal agent aqueous solution A; mix SFS in the residue removal initiator and residue removal emulsifier with 2 parts by mass of water to obtain residue removal agent aqueous solution B.

[0119] (5) Seed polymerization: Add 33.5 parts by mass of water and 10% by mass of polymerization emulsifier aqueous solution to the polymerization reactor, evacuate to -0.097 MPa, quickly pump in 10% by mass of mixed monomers using a monomer pump, rapidly heat to 65°C, then pump in 20% by mass of polymerization initiator aqueous solution A and 20% by mass of polymerization initiator aqueous solution B, maintain the temperature at 65°C and the stirring speed at 70 rpm, and complete the polymerization within 1 hour.

[0120] (6) Addition polymerization: The remaining 90% of the total mass of the polymerization emulsifier aqueous solution, the remaining 90% of the total mass of the mixed monomers, the remaining 80% of the total mass of the polymerization initiator aqueous solution A, and the remaining 80% of the total mass of the polymerization initiator aqueous solution B are fed into the polymerization reactor at a constant speed within 10 hours, maintaining a rotation speed of 70 rpm and a reaction temperature of 65℃.

[0121] (7) Residue removal: Quickly add the residue removal agent aqueous solution A and residue removal agent aqueous solution B prepared in step (4) into the polymerization kettle, keep warm for 1 hour, and obtain emulsion.

[0122] (8) Spray drying: Cool the emulsion obtained in step (7) to 28°C, filter it with a 300-mesh filter, and dry it by spray drying to obtain the finished resin.

[0123] The inlet air temperature of the spray dryer is controlled at 200℃, and the outlet air temperature of the spray dryer is controlled at 90℃.

[0124] Example 5 This embodiment provides a PVDC resin composition, the composition of which is as follows: VDC monomer: 51.4836 parts by weight Comonomer: 3.5906 parts by weight Hydrophilic monomer: 0.1657 parts by weight Polymerizing emulsifier: 1.04956 parts by weight Polymerization initiator: 0.1776 parts by weight Residue-removing initiator: 0.245 parts by weight Eliminating emulsifier: 0.029 parts by weight Water: 52.5 parts by weight; in, The comonomer consists of 1.1048 parts by weight of methyl methacrylate (MMA) and 2.4858 parts by weight of acrylonitrile (AN); The hydrophilic monomer is methacrylic acid (MAA); The polymeric emulsifier is a polyoxyethylene ether salt containing double bonds, specifically a polyoxyethylene ether phosphate containing double bonds, with the structural formula as follows: Where R1 is a C3 straight-chain alkylene group -CH2CH2CH2-, and R2 is -PO3² - Na2 + n is the degree of aggregation, n=6; The residual emulsifier is an alkyl succinate salt containing a double bond, specifically an alkyl sulfonyl succinate salt containing a double bond group, with the structural formula as follows: Where R1 is a C4 straight-chain alkylene group -CH2CH2CH2CH2-, R2 is a C6 straight-chain alkyl group -CH2CH2CH2CH2CH2CH3, R3 is a C3 straight-chain alkyl group -CH2CH2CH3, and R4 is -SO3. - Na + .

[0125] The polymerization initiator consists of 0.096 parts by mass of tert-butyl hydroperoxide (TBHP) and 0.0816 parts by mass of sodium thiosulfate (SFS); The residue-eliminating initiator consists of 0.137 parts by weight of tert-butyl hydroperoxide (TBHP) and 0.108 parts by weight of sodium thiosulfate (SFS); The water is deionized.

[0126] A method for preparing PVDC resin using the PVDC resin composition as a reactant includes the following steps: (1) Preparation of mixed monomers: Mix VDC monomers, comonomers and hydrophilic monomers evenly to obtain mixed monomers.

[0127] (2) Prepare an aqueous solution of polymer emulsifier: Mix the polymer emulsifier with 5 parts by mass of water to obtain an aqueous solution of polymer emulsifier.

[0128] (3) Prepare the polymerization initiator aqueous solution: Mix TBHP in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution A; mix SFS in the polymerization initiator with 5 parts by mass of water to obtain polymerization initiator aqueous solution B.

[0129] (4) Prepare the residue removal agent aqueous solution: Mix TBHP in the residue removal initiator with 2 parts by mass of water to obtain residue removal agent aqueous solution A; mix SFS in the residue removal initiator and residue removal emulsifier with 2 parts by mass of water to obtain residue removal agent aqueous solution B.

[0130] (5) Seed polymerization: Add 33.5 parts by mass of water and 10% by mass of polymerization emulsifier aqueous solution to the polymerization reactor, evacuate to -0.097 MPa, and quickly pump in 10% by mass of mixed monomers using a monomer pump. After rapidly heating to 62°C, pump in 20% by mass of polymerization initiator aqueous solution A and 20% by mass of polymerization initiator aqueous solution B. Maintain the temperature at 62°C and the stirring speed at 80 rpm, and complete the polymerization within 1 hour.

[0131] (6) Addition polymerization: The remaining 90% of the total mass of the polymerization emulsifier aqueous solution, the remaining 90% of the total mass of the mixed monomers, the remaining 80% of the total mass of the polymerization initiator aqueous solution A, and the remaining 80% of the total mass of the polymerization initiator aqueous solution B are fed into the polymerization reactor at a constant speed within 10 hours, maintaining a rotation speed of 80 rpm and a reaction temperature of 62℃.

[0132] (7) Residue removal: Quickly add the residue removal agent aqueous solution A and residue removal agent aqueous solution B prepared in step (4) into the polymerization kettle, keep warm for 0.5h, and obtain emulsion.

[0133] (8) Spray drying: Cool the emulsion obtained in step (7) to 28°C, filter it with a 300-mesh filter, and dry it by spray drying to obtain the finished resin.

[0134] The inlet air temperature of the spray dryer is controlled at 220℃, and the outlet air temperature of the spray dryer is controlled at 95℃.

[0135] Example 6 This embodiment is basically the same as embodiment 2, except that: In the PVDC resin composition, both the polymerization emulsifier and the residue-eliminating emulsifier are polyoxypropylene ether salts containing double bonds. The structural formula of the polyoxypropylene ether salt containing double bonds is as follows: Where R1 is -CH2- and R2 is -PO3² - Na2 + , where n is the degree of aggregation, n=4.

[0136] Example 7 This embodiment is basically the same as embodiment 2, except that: In the PVDC resin composition: The polymeric emulsifier is a polyoxypropylene ether salt containing double bonds, and the structural formula of this polyoxypropylene ether salt containing double bonds is as follows: Where R1 is -CH2- and R2 is -PO3² - Na2 + , where n is the degree of aggregation, n=4.

[0137] The residual emulsifier is an alkyl succinate salt containing double bonds, and the structural formula of the alkyl succinate salt containing double bonds is as follows: R1 is -CH2-, R2 and R3 are both H atoms, and R4 is -PO3². - Na2 + .

[0138] Example 8 This embodiment is basically the same as embodiment 2, except that: In the PVDC resin composition, the polymerization emulsifier and the residue-reducing emulsifier are different. The polymerization emulsifier is the same as in Example 2, and the residue-reducing emulsifier is a mixture of polyoxypropylene ether salt containing double bonds, alkyl succinate salt containing double bonds, and polyoxyethylene ether salt containing double bonds in a mass ratio of 1:1:1.

[0139] in: The structural formula of polyoxypropylene ether salts containing double bonds is: Where R1 is -(C(CH3)CH2CH3)- and R2 is -SO3 - NH4 + , where n is the degree of aggregation, n=2.

[0140] The structural formula of alkyl succinate salts containing double bonds is: R1 is -CH2-, R2 and R3 are both H atoms, and R4 is -PO3². - Na2 + .

[0141] The structural formula of polyoxyethylene ether salts containing double bonds is: Where R1 is -CH2CH2- and R2 is -OSO3 - K + , where n is the degree of aggregation, n=8.

[0142] Example 9 This embodiment is basically the same as embodiment 2, except that: In the PVDC resin composition, the polymerization emulsifier and the residual emulsifier are the same, which are a mixture of polyoxypropylene ether salt containing double bonds, alkyl succinate salt containing double bonds, and polyoxyethylene ether salt containing double bonds in a mass ratio of 1:1:1.

[0143] in: The structural formula of polyoxypropylene ether salts containing double bonds is: Where R1 is -(C(CH3)CH2CH3)- and R2 is -SO3 - NH4 + , where n is the degree of aggregation, n=2.

[0144] The structural formula of alkyl succinate salts containing double bonds is: R1 is -CH2-, R2 and R3 are both H atoms, and R4 is -PO3². - Na2 + .

[0145] The structural formula of polyoxyethylene ether salts containing double bonds is: Where R1 is -CH2CH2- and R2 is -OSO3 - K + , where n is the degree of aggregation, n=8.

[0146] Example 10 This embodiment is basically the same as embodiment 2, except that: In the PVDC resin composition, the comonomer is methyl acrylate (MA), and the content of the comonomer is 4.0325 parts by weight.

[0147] Example 11 This embodiment is basically the same as embodiment 2, except that: In the PVDC resin composition, the comonomer is acrylonitrile (AN), and the content of the comonomer is 4.0325 parts by mass.

[0148] Comparative Example 1 This comparative example is basically the same as Example 2, except that: In the PVDC resin composition, the "methyl acrylate (MA)" in the comonomer is replaced with "butyl acrylate (BA)".

[0149] Comparative Example 2 This comparative example is basically the same as Example 2, except that: In the PVDC resin composition: Both the polymerization emulsifier and the residue-eliminating emulsifier are polyoxyethylene ether salts containing double bonds, specifically sodium polyoxyethylene ether sulfate containing double bonds, with the structural formula as follows: R1 is a C8 straight-chain alkylene group -CH2(CH2)6CH2-, and R2 is -OSO3. - Na + , where n is the degree of aggregation, n=10.

[0150] Comparative Example 3 The PVDC resin composition of this comparative example has the following composition: 40kg of deionized water Sodium pyrophosphate 22g 20g of methylcellulose ether VDC monomer 21kg 9 kg of vinyl chloride (VCM) monomer 500g of butyl methacrylate and methyl methacrylate copolymer resin 75g of diisopropyl peroxide dicarbonate Epoxidized soybean oil 61.3g Dibutyl subebrate 166.7g Stearamide 7.6g Oleamide 7.6g; Sodium pyrophosphate is a pH buffer regulator, methyl cellulose ether is a dispersant, diisopropyl peroxide dicarbonate is an initiator, epoxidized soybean oil and dibutyl sebate are plasticizers, and stearamide and oleamide are lubricants.

[0151] A method for preparing PVDC resin using the PVDC resin composition as a reactant includes the following steps: (1) Preparation of pH buffer solution and dispersant solution: 22g of sodium pyrophosphate was prepared into pH buffer solution with 2kg of deionized water; 20g of methyl cellulose ether was prepared into dispersant solution with 5kg of deionized water; (2) Add 5 kg of deionized water to a 100 L polymerization reactor (a stainless steel polymerization reactor with a stirring device, a length-to-diameter ratio of 2:1, and a double-layered, two-bladed, 45° inclined paddle), seal the reactor, test for pressure and leaks, and after evacuation, add VDC monomer, VCM monomer, diisopropyl peroxide, butyl methacrylate and methyl methacrylate copolymer resin. After dispersing at 90 rpm / min for 30 minutes, add the dispersant aqueous solution, pH buffer adjustment aqueous solution and the remaining deionized water. After cold dispersion for 35 minutes, pass hot water through the jacket of the polymerization reactor at a stirring speed of 120 rpm / min to quickly raise the temperature to 39°C to start the polymerization reaction. At the same time, increase the reaction temperature at a rate of 0.6°C / h. After reacting for 1000 min, increase the stirring speed at a rate of 2 rpm / h to continue the reaction. (3) After 40 hours of reaction, a significant pressure drop occurs in the reactor, the polymerization reaction is terminated, the residual monomer is removed under vacuum, and the product is cooled, centrifuged, and dried. (4) Add 61.3g of epoxidized soybean oil, 166.7g of dibutyl sebacate, 7.6g of stearamide, and 7.6g of oleamide to the dried material, heat it to 65°C in a mixer, mix and mature to obtain the product resin.

[0152] Comparative Example 4 The PVDC resin composition of this comparative example has the following composition: 10 kg of vinylidene chloride (VDC) monomer 15kg of acrylonitrile (AN) monomer Sodium allyl sulfonate 0.75 kg 0.25 kg of methyl acrylate Allyl didodecyl sulfosuccinic acid 0.25 kg Polymerization initiator: tert-butyl hydroperoxide (TBHP) 30g Sculpting powder (SFS) 30g Residue-reducing initiator: 150g tert-butyl hydroperoxide 150g of sculpting powder 70kg of deionized water.

[0153] A method for preparing PVDC resin using the PVDC resin composition as a reactant includes the following steps: (1) Preparation of emulsifier aqueous solution: Weigh 0.25 kg of allyl bis(dodecyl)sulfosuccinic acid and prepare an emulsifier aqueous solution with 3 kg of deionized water for later use; (2) Preparation of polymerization initiator aqueous solution: Weigh 30g of TBHP and prepare TBHP aqueous solution with 5Kg of deionized water for later use; Weigh 30g of SFS and prepare SFS aqueous solution with 5Kg of deionized water for later use. (3) Prepare the aqueous solution of the residue removal initiator: Weigh 150g of TBHP and prepare an aqueous solution of TBHP with 2Kg of deionized water for later use; Weigh 150g of SFS and prepare an aqueous solution of SFS with 2Kg of deionized water for later use. (4) Seed emulsion polymerization: First, put the remaining deionized water into the polymerization kettle, evacuate the polymerization kettle to -0.095Mpa, and keep the vacuum at this level. Pump 1Kg vinylidene chloride monomer, 1.5Kg acrylonitrile monomer, 75g sodium allyl sulfonate, 25g methyl acrylate and 10% of the emulsifier aqueous solution prepared in step (2) into the polymerization kettle. Disperse cold at 100rpm for 20 minutes, keep the speed at this level and raise the temperature to 50℃. Then, add 10% of the TBHP aqueous solution prepared in step (3) and 10% of the SFS aqueous solution prepared in step (3) at a uniform rate within 1h to react. The reaction time is 1h to obtain the seed emulsion. (5) Addition polymerization: Keep the temperature of the polymerization kettle at 50°C and the stirring speed at 100 rpm. Add the remaining emulsifier aqueous solution, the remaining vinylidene chloride monomer, the remaining acrylonitrile monomer, the remaining sodium allyl sulfonate, the remaining methyl acrylate, the remaining TBHP aqueous solution and SFS aqueous solution prepared in step (3) to the seed emulsion obtained in step (5) and react for 8 hours to end the reaction and obtain the reaction product. (6) Post-processing: Under the condition of maintaining the polymerization reactor temperature at 50℃ and stirring speed at 100rpm, the TBHP aqueous solution and SFS aqueous solution prepared in step (4) are uniformly fed into the polymerization reactor within 30 minutes. After the feeding is completed, the temperature is lowered to 30℃ and the material is discharged. After mechanical demulsification, the obtained material is put into a flash tank for drying. The flash temperature is 60℃ and the flash pressure is -0.07MPa. After flash drying, it is put into a fluidized bed for drying at 45℃, and finally the finished resin is obtained.

[0154] Comparative Example 5 This comparative example is basically the same as Example 2, except that: The PVDC resin composition does not contain residual emulsifiers.

[0155] In the method for preparing PVDC resin using the PVDC resin composition as a reactant: In step (4), no residue-removing emulsifier is added when preparing the aqueous solution B of the residue-removing agent; Comparative Example 6 This comparative example is basically the same as Example 2, except that: The PVDC resin composition does not contain the hydrophilic monomer acrylic acid (AA).

[0156] In the method for preparing PVDC resin using the PVDC resin composition as a reactant: The process of preparing the mixed monomers in step (1) does not involve adding the hydrophilic monomer acrylic acid (AA).

[0157] Comparative Example 7 This comparative example is basically the same as Example 2, except that: In the PVDC resin composition, the content of VDC monomer is 45 parts by weight.

[0158] II. Performance Testing 1. Emulsion performance testing The solid content, viscosity, surface tension, and residual vinylidene chloride content of the PVDC emulsions after residual removal during the preparation of PVDC resin in each example and comparative example (except for comparative examples 3-4), and the PVDC emulsion before mechanical demulsification in comparative example 4, were tested respectively. The test methods are as follows: Determination of solid content in emulsion: The determination shall be carried out in accordance with the method specified in SH / T 1154 "Determination of total solid content in synthetic rubber latex".

[0159] Determination of emulsion viscosity: The viscosity shall be determined in accordance with the method specified in SH / T 1152 "Determination of apparent viscosity of synthetic rubber latex".

[0160] Determination of surface tension of emulsion: The determination shall be carried out in accordance with the method specified in SH / T 1156 "Determination of surface tension of synthetic rubber latex".

[0161] Determination of residual vinylidene chloride content in emulsion: The determination was performed according to section 6.7 of T / ZZB 0285-2017. The chromatographic column used was a DB-WAX, 60 m long, 0.53 mm inner diameter, and 1.0 μm film thickness.

[0162] The results of the emulsion performance test are shown in Table 1.

[0163] 2. Resin performance testing The weight-average molecular weight (Mw), D50 particle size, specific surface area, solubility, and adhesion of the PVDC resin products prepared in each example and comparative example were tested respectively. The test methods are as follows: Resin weight-average molecular weight: Tested using a WaterS ACQUITY ultra-high performance gel permeation chromatograph.

[0164] Resin D50 particle size: measured using a Mastersizer 3000+ Ultra laser particle size analyzer.

[0165] Specific surface area: Specific surface area = surface area / volume = (4πR) 2 ) / 4 / 3ΠR3)=3 / R(The resin particles are estimated based on complete spherical resin particles).

[0166] Solubility test: The prepared resin was dissolved in N,N-dimethylacetamide at a solid content of 20%, and the time required for it to dissolve in a 60°C water bath was measured.

[0167] Adhesion: Refer to GB / T 9286 The test was conducted according to the 2021 standard "Cross-cut test for paints and varnishes".

[0168] The results of the resin performance test are shown in Table 2.

[0169] 3. Barrier performance test The PVDC resins obtained in each embodiment and comparative example were used to prepare barrier membranes, and the oxygen permeability and water vapor permeability of each barrier membrane were then tested. Wherein: Preparation of the barrier membrane: The prepared PVDC resin was dissolved in N,N-dimethylacetamide to obtain a PVDC solution. Subsequently, a 0.5 g / m² substrate was first applied to a PET film. 2 Apply polyurethane adhesive, then top coat with 3.2g / m². 2 A PVDC solution was used to obtain a barrier membrane.

[0170] Oxygen permeability test: The test shall be conducted in accordance with the method specified in GB / T 1038.2-2022 "Test method for gas permeability of plastic films and sheets - Part 2: Isobaric method".

[0171] Water vapor transmission rate test: The test shall be conducted in accordance with the method specified in GB / T 1037-2021 "Determination of water vapor transmission performance of plastic films and sheets by cup weight gain and weight loss method".

[0172] The results of the barrier performance test are shown in Table 3.

[0173] Table 1. Results of emulsion performance tests

[0174] As can be seen from Table 1: The solid content of Examples 1-11, Comparative Examples 1-2, and Comparative Examples 5-7 can reach more than 50 wt%, while Comparative Example 4 has only 23.2 wt% and Comparative Example 6 has only 45.1 wt%. This is because a small amount of hydrophilic monomers were introduced into Examples 1-11, Comparative Examples 1-2, and Comparative Examples 5-7, which makes the emulsion have better stability and can prepare PVDC emulsions with higher solid content.

[0175] Furthermore, the VDC residue levels in Examples 1-11, Comparative Examples 1-2, and Comparative Examples 6-7 were all below 150 ppm, while the VDC residue level in Comparative Example 4 was 367 ppm and the VDC residue level in Comparative Example 5 was 424 ppm. This is because a small amount of residue-reducing emulsifier was introduced in Examples 1-11, Comparative Examples 1-2, and Comparative Examples 6-7 during the residue reduction stage. These free residue-reducing emulsifiers can better emulsify monomers that did not participate in the reaction and, under the action of the residue-reducing initiator, can better participate in the reaction.

[0176] Table 2 Resin Performance Tests

[0177] As can be seen from Table 2: Compared to Comparative Examples 3-4, Examples 1-11 and Comparative Examples 1-2 and 5-7 exhibited shorter dissolution times. This is because the D50 particle size of Examples 1-11 and Comparative Examples 1-2 and 5-7 was below 40 µm, and their specific surface area was 1.667 × 10⁻⁶. 5 The molecular weights in these examples are between 60,000 and 80,000. This is because the molecular chains are short, making them easy to open under the action of the solvent. Furthermore, the smaller particle size ensures a larger contact area between the resin and the solvent. In Comparative Example 3, compared to Examples 1-11, both the D50 particle size and molecular weight are increased. In Comparative Example 4, compared to Examples 1-11, both the D50 particle size and molecular weight are significantly increased, resulting in a substantial increase in dissolution time.

[0178] The adhesion grades of Examples 1-11 and Comparative Examples 1-2, 5 and 7 are all less than or equal to grade 1, while the adhesion grades of Comparative Examples 3-4 and 6 are 2. This is because a small amount of hydrophilic monomers were introduced in Examples 1-11 and Comparative Examples 1-2, 5 and 7 to increase the polarity of PVDC, which significantly improves its adhesion to the substrate film.

[0179] Table 3 Barrier performance test results

[0180] As can be seen from Table 3: Examples 1-11 and Comparative Examples 5-6 clearly exhibited lower oxygen and water vapor permeability. The slightly poorer barrier properties of Comparative Example 1 were due to the introduction of long-chain acrylate monomers, which disrupted the regularity of the molecular chains. Similarly, the slightly poorer barrier properties of Comparative Example 2 were due to the introduction of long-chain polymerizing emulsifiers, which also disrupted the regularity of the molecular chains. The poor barrier properties of Comparative Examples 3, 4, and 7 were because the mass ratio of VDC monomers in the PVDC resin compositions used as reactants was too low, resulting in insufficiently regular PVDC chains.

[0181] 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.

[0182] 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 PVDC resin composition, characterized in that, It includes dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residue-reducing emulsifier, and residue-reducing initiator; the comonomer includes at least one of acrylate monomers and acrylonitrile monomers; the polymerization emulsifier and the residue-reducing emulsifier each independently include at least one of alkyl succinate salt containing double bonds, polyoxyethylene ether salt containing double bonds, and polyoxypropylene ether salt containing double bonds.

2. The PVDC resin composition according to claim 1, characterized in that, The polyoxypropylene ether salt containing double bonds includes at least one of the compounds represented by Formula I: Formula I, In Formula I, R1 is a C1-C6 straight-chain alkylene group or a C1-C6 branched alkylene group, R2 is one of sulfate group, sulfonate group or phosphate group; n is the degree of polymerization, and the value of n is in the range of 2-6; the sum of the number of carbon atoms in R1 and 3n is less than or equal to 21.

3. The PVDC resin composition according to claim 1, characterized in that, The alkyl succinate salt containing double bonds includes at least one of the compounds represented by Formula II: Formula II, In Formula II, R1 is a C1-C6 straight-chain alkylene or a C1-C6 branched alkylene, R2 and R3 are each independently one of H atom, C2-C8 straight-chain alkyl, or C2-C8 branched alkyl, R4 is one of phosphate group, sulfonate group or sulfate group, and the total number of carbon atoms of R1, R2 and R3 is less than or equal to 18.

4. The PVDC resin composition according to claim 1, characterized in that, The polyoxyethylene ether salt containing double bonds includes at least one of the compounds represented by Formula III: Formula III, In Formula III, R1 is a straight-chain alkylene group of C1-C6 or a branched alkylene group of C1-C6, R2 is one of sulfate group, sulfonate group or phosphate group; n is the degree of polymerization, and the value of n is in the range of 2-8; the sum of the number of carbon atoms in R1 and 2n is less than or equal to 18.

5. The PVDC resin composition according to claim 1, characterized in that, The mass ratio of the dichloroethylene monomer, comonomer, hydrophilic monomer, polymerization emulsifier, polymerization initiator, residue-reducing emulsifier, and residue-reducing initiator is (50.8208-51.6494): (3.3696-4.143): (0.11048-0.2762): (0.8286-1.04956): (0.159-1.10955): (0.026-0.029): (0.2-0.264).

6. The PVDC resin composition according to any one of claims 1 to 5, characterized in that, The acrylate monomers are short-chain acrylate monomers; the acrylonitrile monomers are short-chain acrylonitrile monomers.

7. The PVDC resin composition according to claim 6, characterized in that, The short-chain acrylate monomers include at least one of methyl acrylate, methyl methacrylate, and ethyl acrylate; And / or, the short-chain acrylonitrile monomer includes at least one of acrylonitrile and methacrylonitrile.

8. The PVDC resin composition according to any one of claims 1 to 5, characterized in that, The hydrophilic monomer includes at least one of acrylic acid, methacrylic acid, and hydroxyethyl acrylate.

9. The PVDC resin composition according to any one of claims 1 to 5, characterized in that, The polymerization initiator comprises tert-butyl hydroperoxide and sodium chloroform, and the mass ratio of tert-butyl hydroperoxide to sodium chloroform is (0.084-0.1113):(0.075-0.99825). And / or, the residue removal initiator comprises tert-butyl hydroperoxide and sodium styrax, and the mass ratio of tert-butyl hydroperoxide to sodium styrax is (0.11-0.144):(0.09-0.12).

10. The PVDC resin composition according to any one of claims 1 to 5, characterized in that, The PVDC resin composition further includes water, wherein the mass ratio of water to the dichloroethylene monomer is (52-54):(50.8208-51.6494). Preferably, when the PVDC resin composition further includes water, the dichloroethylene monomer in the PVDC resin composition has a mass content of 45% or more.

Images