KR20020057422A - A process for the preparation of high-impact graft copolymer of vinyl chloride - Google Patents

Abstract

PURPOSE: Provided is a process for producing a vinyl chloride resin excellent in impact-resistance by graft-copolymerizing an acryl elastic latex and vinyl chloride monomers without using special additives for reinforcing the impact. CONSTITUTION: The process comprises the steps of: preparing the acryl copolymer latex by using acrylate monomers and a multi-functional crosslinking agent, wherein the acryl copolymer latex has a glass transition temperature of -140 to 30deg.C, the gel content of more than 30wt%, and a size of 10-1000nm and the acrylate monomer is selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, or a mixture thereof and the multi-functional crosslinking agent is selected from the group consisting of ethylene glycol (meth)acrylate, diethylene glycol (meth)acrylate, 1,6-hexanediol(meth)acrylate, and etc.; graft-copolymerizing the acryl copolymer latex and the vinyl chloride monomers.

Description

A method for producing a vinyl chloride-based resin having excellent impact resistance {A PROCESS FOR THE PREPARATION OF HIGH-IMPACT GRAFT COPOLYMER OF VINYL CHLORIDE}

The present invention relates to a method for producing a vinyl chloride resin having excellent impact resistance. More specifically, the present invention provides a vinyl chloride-based graft copolymer resin having excellent impact strength while minimizing adhesive formation without using an additive to improve processability and weatherability of the vinyl chloride-based graft copolymer resin. It is about a method.

Vinyl chloride-based resin is a resin excellent in mechanical tensile strength and chemical resistance has been used in various applications. However, when used for hard use, the impact strength is weak, there is a disadvantage that the molded product is easily broken even in the slight impact of daily life. Conventionally, in order to compensate for these disadvantages, Japanese Patent 11,228,772 (1999) of Japan's Integral Chemistry, European Patent 0,713,892 (1996) of Solvay, and US Patent (1993) of Hules, Germany, disclose that unsaturated double bonds with acrylate monomers A method for producing a vinyl chloride-based graft copolymer resin by graft copolymerization of vinyl chloride on an acrylic copolymer composed of multiple polyfunctional monomers has been proposed. However, the vinyl chloride-based graft copolymer resin prepared according to the above method improves impact resistance as the content of the acrylic elastomer component increases, but it is difficult to process, resulting in a lot of unmelted protrusions on the surface of the molded article, and weather resistance is weak, so discoloration may occur during long-term use. There was a problem that occurred. In addition, in the conventional method, the acrylic elastomer latex and the suspension stabilizer are collectively added at the beginning of the graft copolymerization reaction to prepare a vinyl chloride-based resin, resulting in unstable particle formation, and thus have problems in implementation. In the case of preparing the graft copolymer resin, a large amount of resin adhesive is formed around the reactor wall and the stirrer when the resin is manufactured, and there is a problem of inhibiting the trouble of having to wash the reactor every time the preparation and the stability of the process. In order to solve such weak processability and weather resistance, using a large amount of processing aids or additives for improving weather resistance can improve the effect. However, since the processing aid and the additives for improving weather resistance of vinyl chloride resins are very expensive, they are economically efficient. There is a limit to the industrial utilization is reduced, there is also a problem in that the formation of the resin adhesive in terms of stability of the resin manufacturing process.

Therefore, there is a demand for a method for producing a vinyl chloride-based copolymer resin having excellent impact strength without using an additional impact reinforcing additive.

The present invention has been made to solve the above problems, the present inventors by producing a vinyl chloride-based copolymer resin by a method of manufacturing a vinyl chloride-based graft copolymer resin composed of two steps without using a separate impact reinforcing additives A vinyl chloride-based graft copolymer resin having excellent impact properties can be prepared. Particularly, in the case of the graft suspension copolymerization reaction, a suspension stabilizer is added in the middle of the reaction instead of a batch at the beginning of the reaction to improve particle stability and impact resistance and processability of the final resin. It has been found that the present invention can be completed.

Accordingly, an object of the present invention is to provide a method for producing a vinyl chloride-based graft copolymer resin having excellent impact strength without using an additional impact reinforcing additive.

In order to achieve the above object, the present invention (a) preparing an acrylic elastomer latex using an acrylate monomer and a multifunctional crosslinking agent, and (b) a vinyl chloride-based to the acrylic elastomer latex prepared in step (a) It provides a method for producing a vinyl chloride-based resin having excellent impact resistance comprising graft copolymerization of a monomer.

Hereinafter, the present invention will be described in detail.

(A) A method for producing an acrylic elastomer.

Step (a) is a step of preparing an acrylic elastomer latex using an alkylacrylate monomer and a multifunctional crosslinking agent.

In order to manufacture the vinyl chloride-based graft copolymer resin having excellent impact strength, the glass transition temperature, the gel content and the size of the acrylic elastomer in the step (a) must be appropriately controlled.

In order to exhibit the impact strength of the final vinyl chloride-based graft copolymer resin, the glass transition temperature of the acrylic elastomer prepared in step (a) is preferably -140 to 30 ° C. The glass transition temperature of the elastomer is determined by the type of monomer constituting the elastomer, and suitable acrylic monomers are methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, and n-butyl (meth). Acrylate, sec-butyl acrylate, isobutyl acrylate, cumyl acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl ( Meth) acrylate, 2-methylheptyl (meth) acrylate, 2-methylheptyl (meth) acrylate, n-decyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, Myristyl (meth) acrylate, n-nonyl (meth) acrylate, palmityl methacrylate, stearyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and this It can be used selected from the group consisting of a mixture of these. Preferably, monomers selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate or mixtures thereof are used.

In addition, in order to produce a vinyl chloride-based graft copolymer resin having excellent impact strength, the gel content of the acrylic elastomer is preferably 30% by weight or more. The gel content of the elastomer is a physical property determined by the degree of crosslinking of the elastomer, and the crosslinking degree is a physical property determined by the type and amount of the multifunctional crosslinking agent used to prepare the acrylic elastomer in step (a). Di (meth) acrylate and tri (meth) acrylates can be used as a suitable polyfunctional crosslinking agent. Specific examples of the di (meth) acrylate-based polyfunctional monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, and 1,6-hexanediol. (Meth) acrylate etc. are mentioned, The specific example of a tri (meth) acrylate type polyfunctional monomer is a trimethylol propane tri (meth) acrylate, an ethylene oxide modified trimethylol propane tri (meth) acrylate, penta Erysdol tree (meth) acrylate, etc. are mentioned. Moreover, as a polyfunctional crosslinking agent which can be used other than the above, divinyl compounds, such as pentaerythol tetra (meth) acrylate, dipentaerythol hexa (meth) acrylate, diallyl phthalate, diallyl maleate, divinylbenzene, butadiene, etc. There is this. The crosslinking agent may be used alone or in combination of two or more. When the polyfunctional monomer is excessively used, the crosslinking degree in the acrylic elastomer is excessively increased, the gel content is 90% by weight or more, and the impact strength and tensile strength are lowered. The amount thereof is preferably 0.1 to 30 parts by weight, more preferably 0.3 to 5 parts by weight with respect to 100 parts by weight of the acrylic monomer.

In order to produce a vinyl chloride-based graft copolymer resin having excellent impact strength, the size of the acrylic elastomer is preferably 10 to 1,000 nm, more preferably 50 to 500 nm. In order to appropriately control the size of the acrylic elastomer in order to exhibit excellent impact strength, the emulsion dropping emulsion polymerization method of growing the size of the acrylic elastomer latex while continuously adding an emulsion reaction solution consisting of monomer, polymerization initiator, emulsifier and water during the reaction. Alternatively, the step (a) may be performed by using a deep emulsion emulsion polymerization method in which an emulsion reaction solution is added together with an acrylic elastomer latex seed particle in a continuous or semi-batch manner to grow the size of the acrylic elastomer latex.

In order to demonstrate the impact strength of the acrylic elastomer in step (a), the reaction water, the acrylic monomer and the crosslinking agent are introduced into the reactor, and the vacuum is added by adding an emulsifier, a polymerization initiator and a hydrogen ion concentration regulator. After the addition, the mixture was heated with stirring to prepare an acrylic elastomer latex. The polymerization initiator used to prepare the acrylic elastomer latex may be both water-soluble and oil-soluble initiators. As the water-soluble initiator, sulfate salts of potassium persulfate or ammonium persulfate and water-soluble peroxides of t-butyl hydroperoxide or hydrogen peroxide can be used. Weight part is preferable. If the amount of the initiator is less than 0.1 part by weight in step (a), the reaction is severely delayed. If the amount is more than 1 part by weight, the unreacted initiator remains, which results in a problem of deterioration of color change, weather resistance and thermal stability. In addition, redox catalysts of sodium formaldehyde sulfoxide, ferrous sulfate, and ethylene sodium diamine tetra acetate can be used together to control the polymerization activity. As the oil-soluble initiator, propionyl peroxide, lauryl peroxide, organic peroxides of acetyl peroxide, etc. may be used, and a redox catalyst of copper sulfate and ascorbic acid may be used together to control the polymerization activity. In order to control the polymerization activity, the redox catalyst used together with the polymerization initiator affects the color and weather resistance of the final resin, so the amount of the redox catalyst should be maintained at an appropriate level. The amount of monomer used in step (a) The range of 0.2 to 0.6 parts by weight is preferred.

In order to proceed smoothly in step (a) it is effective to maintain the hydrogen ion concentration in the pH range of 6 to 8, for this purpose it is possible to use a hydrogen ion regulator, it is preferable to use sodium bicarbonate or sodium hydroxide solution. The reaction temperature for preparing the acrylic elastomer in step (a) is preferably 60 to 80 ° C.

In addition, in order to improve the mechanical stability of the acrylic elastomer latex, it is preferable to add a small amount of protective colloidal agent after the type of latex polymerization reaction.

(B) vinyl chloride graft copolymerization step

Step (b) is a step of graft copolymerization of the vinyl chloride monomer on the acrylic elastomer latex prepared in step (a).

In the step (b), a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, a bulk polymerization method, etc. may be used.

In the graft suspension polymerization of step (b), water and a vinyl chloride monomer, a polymerization initiator and a suspension stabilizer are added to the acrylic elastomer latex prepared in step (a), and the graft polymerization is performed at a predetermined reaction temperature. To prepare a vinyl chloride-based graft copolymer resin having excellent chargeability.

The vinyl chloride monomer refers to a monomer having a vinyl chloride content of 50% by weight or more.

Other monomers may be used together with vinyl chloride in order to improve physical properties such as processability, weather resistance or thermal stability of the vinyl chloride resin. Examples of monomers that can be used with vinyl chloride include anionic surfactants, nonionic surfactants, partially saponified vinyl acetate, cellulose dispersants, gelatin, and the like, which are used to efficiently perform polymerization by improving dispersion stability. Used for the purpose. The monomers usable in admixture with the vinyl chloride are preferably vinyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, ethylene, propylene and mixtures thereof.

The suspending stabilizer is a partially saponified vinyl acetate polymer having a saponification degree of 70 to 90 mol% and a viscosity of 4 wt% aqueous solution of 30 to 60 cP, a propyl cellulose cellulose having a viscosity of 50 to 1,000 cP of 2 wt% aqueous solution and 2 wt% Preferably, the aqueous solution is selected from the group consisting of carboxylated cellulose having a viscosity of 50 to 1,000 cP, the amount of which is preferably used in an amount of 0.2 to 5 parts by weight based on 100 parts by weight of the total monomers used in step (b). Do. In addition, the suspension stabilizer is preferably introduced into the reactor when the reaction conversion rate of the graft copolymerization reaction of step (b) is 5 to 50%.

Examples of the polymerization initiator include water-soluble initiators such as potassium persulfate, ammonium persulfate and hydrogen peroxide, benzoyl peroxide, lauryl peroxide, acetylcyclohexanolsulfonyl peroxide, 2,4,4-trimethylpentyl-2- Peroxy neodecanoate, α-cumyl peroxy neodecanoate, dibutyl peroxydicarbonate, diisopropylperoxydicarbonate, 2-ethylhexyl peroxydicarbonate, tert-butylperoxy neodecanoate, cumenehydr Organic peroxides such as loperoxide, tert-butylhydroxy peroxide and the like, and azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile and the like.

In the suspension polymerization method, a dispersant and an oil-soluble initiator can be used.

The dispersant is used to improve the dispersion stability of the acrylic copolymer latex and to efficiently perform graft copolymerization of vinyl chloride, and examples thereof include poly (meth) acrylate and acrylate-alkyl (meth) acrylate copolymers. , Methyl cellulose, ethyl cellulose, hydroxypropyl methyl cellulose, polyethylene glycol, partial saponification of vinyl acetate polymer, gelatin, polyvinylpyrrolidone, maleic anhydride-styrene copolymer, and the like. Can be used in combination.

Examples of the oil-soluble initiator include lauryl peroxide, t-butylperoxypivalate, diisopropyl neodecanoate, t-butylperoxy neodecanoate, α-cumylperoxy neodecanoate, dibutyl Azobisiso and organic peroxides such as peroxydacarbonate, diisopropylperoxydicarbonate, 2-ethylhexylperoxydicarbonate, tert-butylperoxy neodecanoate, cumene hydroperoxide, tert-butylhydroxy peroxide and the like Organic compounds such as butyronitrile, azobis-2,4-dimethylvaleronitrile and the like.

In addition, in the said suspension polymerization method, a pH adjuster and antioxidant can be used as needed.

The process of the suspension polymerization method will be described in more detail. After adding pure water, the acrylic copolymer latex, a dispersant, an oil-soluble polymerization initiator, a water-soluble thickener, and a polymerization degree regulator if necessary, a vacuum is added to a reactor equipped with a stirrer and a cooling jacket. The mixture was heated to a predetermined polymerization reaction temperature with vigorous stirring, and the graft suspension polymerization reaction was carried out while maintaining the reaction temperature. After the reaction was completed, unreacted residual vinyl chloride was recovered from the final slurry, dehydrated and dried to prepare a powdered vinyl chloride resin. The vinyl chloride-based resin prepared as described above may be molded by adding a heat stabilizer, a lubricant, a processing aid, an antioxidant, a light stabilizer, etc. as necessary.

The content of the acrylic copolymer latex in the vinyl chloride resin is preferably 30% by weight or less. This is because the higher the content of the acrylic copolymer latex is improved impact resistance but accompanied by a decrease in tensile strength and flexural strength. In addition, the balance of the impact resistance and mechanical strength such as tensile and flexural strength is more preferably 4 to 20% by weight of the acrylic copolymer latex.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but these examples are only for illustrating the present invention, and the present invention is not limited thereto.

Example 1-9

Step 1: Preparation of Acrylic Copolymer Latex

According to the composition of Table 1, a predetermined amount of deionized water, an emulsifier, an acrylic polymerization monomer, a crosslinking agent, and a water soluble initiator were added to potassium persulfate in a reactor in a batch, vacuum was applied, and the temperature was raised to 70 ° C with stirring to prepare an acrylic latex.

Step 2: vinyl chloride graft suspension polymerization

Acryl-based latex, n-butyl acrylate, methyl methacrylate, α-cumyl peroxy neodecanoate and t-butyl peroxy neodecanoate prepared by a one-step polymerization reaction with deionized water are collectively added to the reactor. Then, vacuum was added, vinyl chloride was added with vigorous stirring, and the temperature was raised to 62 ° C. to carry out the graft reaction. During the reaction, a 5 wt% aqueous solution of a partially acetic acid of vinyl acetate polymer was introduced into the reactor. When the reactor pressure reached 2KG / cm ² , the reactor was cooled, and unreacted vinyl chloride monomer was recovered and removed, followed by dehydration and drying to prepare a vinyl chloride resin composition.

Comparative Example 1

Implementation of the prior art

Step 1: Preparation of Acrylic Copolymer Latex

According to the composition of Table 1, a predetermined amount of deionized water, an emulsifier, an acrylic polymerization monomer, a crosslinking agent, and a water soluble initiator were added to the potassium persulfate into the reactor in a batch, vacuum was applied, and the temperature was raised to 70 ° C with stirring to prepare a one-step acrylic latex. It was.

Step 2: vinyl chloride graft suspension polymerization

Acryl-based latex prepared by one-step polymerization with deionized water, 5% aqueous solution of partial acetate of vinyl acetate polymer, α-cumyl peroxy neodecanoate, t-butyl peroxy neodecanoate was added to hanhu vacuum in the vinyl chloride with vigorous stirring and while performing the graft reaction and the temperature was then increased to 62 ℃, the reactor pressure is 2KG / cm ² is reached when the reactor was cooled to recover the unreacted vinyl chloride monomer removed, and then dehydrated And it dried and manufactured the vinyl chloride type resin composition.

Comparative Example 2

Preparation of Vinyl Chloride Resin

According to the composition of Table 1, 5% aqueous saponified part of vinyl acetate polymer, α-cumylperoxy neodecanoate, t-butylperoxy neodecanoate together with deionized water were added to the reactor, and vacuum was added thereto. Vinyl chloride was added with vigorous stirring and the reaction was carried out by raising the temperature to 62 ° C. When the reactor pressure reached 6KG / cm ² , the reactor was cooled, and unreacted vinyl chloride monomer was recovered and removed. It was.

Comparative Example 3

Acrylic impact modifier

7 parts by weight of stabilizer, 5 parts by weight of coal, 1 part by weight of processing aid and 6 parts by weight of acrylic impact modifier were mixed at 120 ° C. for 8 minutes with respect to 100 parts by weight of the vinyl chloride resin prepared in Comparative Example 2, and then cooled. According to the physical properties was evaluated.

[Comparative Example 4]

Butadiene-based impact modifier formulation

7 parts by weight of a stabilizer, 5 parts by weight of coal, 1 part by weight of a processing aid and 7 parts by weight of butadiene-based impact modifier for 8 minutes at 120 ° C., and then cooled to 100 parts by weight of the vinyl chloride resin prepared in Comparative Example 2 The physical properties were evaluated according to the method.

[Comparative Example 5]

Chlorinated Ethylene Polymer Blend

7 parts by weight of a stabilizer, 5 parts by weight of coal, 1 part by weight of a processing aid and 12 parts by weight of chlorinated ethylene polymer were mixed at 120 ° C. for 8 minutes with respect to 100 parts by weight of the vinyl chloride resin prepared in Comparative Example 2, and then cooled. According to the physical properties was evaluated.

[Property evaluation method]

1. Extrusion

7 parts by weight of a stabilizer, 5 parts by weight of coal, and 1 part by weight of a processing aid based on 100 parts by weight of the vinyl chloride resins prepared in Examples 1-9 and Comparative Examples 1 and 2 were mixed and cooled at 120 ° C. for 8 minutes. The extrusion amount and the surface condition of the extrudate were evaluated while extruding at 190 ° C. using a 45 φ extruder.

2. Impact strength

100 parts by weight of the vinyl chloride resin prepared by Examples 1-9 and Comparative Examples 1 and 2, 3 parts by weight of the organic stone stabilizer, 0.5 parts by weight of stearic acid in a 190 ° C roll kneader for 3 minutes after kneading at 190 ° C, pressure 80 The impact strength was evaluated by the Izod impact strength test method of KS M 3055 after fabrication of plate specimens having a thickness of 3 mm by press molding at a pressure of kg / cm ² for 6 minutes.

3. Tensile Strength

Tensile strength evaluation specimens were prepared by the tensile strength test method of KS M 3001 from specimens prepared for impact strength evaluation, and tensile strength was evaluated using a tensile tester.

4. Heat Deflection Temperature

From the specimens prepared for the evaluation of impact strength, specimens for thermal deformation temperature evaluation of KS M 3065 were prepared, and the thermal deformation temperature was evaluated using a thermal deformation temperature gauge.

5. Weather resistance

5 × 3 cm specimens were taken from the specimens prepared for impact strength evaluation and the degree of discoloration was measured using a colorimeter after 20 days of exposure in outdoor daylight.

The physical property evaluation results are shown in Table 2 below.

TABLE 1

division Step 1: preparing acrylic elastomer Deionized Water (parts by weight) n-butyl acrylate (parts by weight) 2-ethylhexyl acrylate (parts by weight) Diallyl phthalate (parts by weight) Allyl methacrylate (parts by weight) Butanediol methacrylate (parts by weight) Medium tank (part by weight) Reaction temperature (℃) Example 1 200 100 - 2 - - 0.2 60 Example 2 200 100 - - 1.5 - 0.2 60 Example 3 200 100 - - - 1.7 0.2 60 Example 4 200 100 - 2 - - 0.2 60 Example 5 200 100 - - 1.5 - 0.2 60 Example 6 200 90 10 - - 1.7 0.2 60 Example 7 200 90 10 2 - - 0.2 60 Example 8 200 90 10 - 1.5 - 0.2 60 Example 9 200 90 10 - - 1.7 0.2 60 Comparative Example 1 200 100 - 2 - - 0.2 60

Table 1-continued

division Step 2: preparing vinyl chloride graft suspension copolymer resin Deionized Water (parts by weight) Acrylic elastomer latex (parts by weight) Vinyl chloride (part by weight) Partial amount of vinyl acetate resin (parts by weight) Particular point of vinyl acetate resin injection (reaction start) Medium tank (part by weight) Reaction temperature (℃) Example 1 180 8 100 0.1 After 0.5 hour 0.2 58 Example 2 180 8 100 0.2 After 1 hour 0.2 58 Example 3 180 8 100 0.4 3 hours later 0.2 58 Example 4 180 8 100 0.2 3 hours later 0.2 58 Example 5 180 8 100 0.4 After 0.5 hour 0.2 58 Example 6 180 8 100 0.1 After 1 hour 0.2 58 Example 7 180 8 100 0.4 After 1 hour 0.2 58 Example 8 180 8 100 0.1 3 hours later 0.2 58 Example 9 180 8 100 0.2 After 0.5 hour 0.2 58 Comparative Example 1 180 8 100 0.1 Initial reaction 0.2 58 Comparative Example 2 180 8 100 0.1 Initial reaction 0.2 58

TABLE 2

division Average particle size (㎛) Formation of adhesive in the reactor (neck side) Extrusion amount (g / min) Extruded Surface (Neck Side) Izod impact strength (kg.cm/c) Tensile Strength (kg / cm ² ) Heat deflection temperature (℃) Weather resistance (yellowness) Example 1 200 X 185 △ 102 516 57.7 13 Example 2 160 O 194 O 108 520 57.1 11 Example 3 160 △ 195 O 102 512 58 13 Example 4 165 △ 193 O 103 511 58.1 12 Example 5 130 O 193 O 103 515 57.5 13 Example 6 180 O 194 O 104 517 57.8 11 Example 7 140 O 192 O 110 523 58.3 13 Example 8 220 X 186 △ 101 510 58.3 12 Example 9 188 O 184 O 113 528 58.4 12 Comparative Example 1 210 X 182 X 98 513 58.3 13 Comparative Example 2 150 O 190 O 4 600 60.5 20.1 Comparative Example 3 O 85 540 58.5 13 Comparative Example 4 O 95 527 59.1 16.4 Comparative Example 5 △ 70 350 58.8 18 Evaluation criteria: 0 excellent, △ normal, X poor

As described above, according to the method of the present invention, it is possible to prepare a vinyl chloride-based graft copolymer having excellent impact strength without using any additives.

Claims (12)

(a) preparing an acrylic copolymer latex using an acrylate monomer and a multifunctional crosslinker; And (b) graft copolymerizing a vinyl chloride monomer on the acrylic copolymer latex prepared in step (a) Method of producing a vinyl chloride-based resin excellent in impact resistance comprising a. The method of claim 1, wherein the acrylic copolymer latex prepared in step (a) has a glass transition temperature of -140 to 30 ° C, a gel content of at least 30% by weight and a size of 10 to 1000 nm. The method according to claim 1 or 2, characterized in that the acrylate monomer used in step (a) is selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate or mixtures thereof. . The polyfunctional crosslinking agent according to claim 1 or 2, wherein the multifunctional crosslinking agent used in step (a) is ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate. , 1,6-hexanediol (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethylene oxide modified trimethylolpropane tri (meth) acrylate, pentaerythritol tree From the group consisting of (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythrole hexa (meth) acrylate, diallyl phthalate, diallyl maleate, divinylbenzene, butadiene and mixtures thereof Selected method. The method according to claim 1 or 2, wherein in the step (a), the multifunctional crosslinking agent is used in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the acrylate monomer. The process according to claim 1 or 2, wherein step (a) is carried out by an emulsion polymerization method. The method according to claim 1 or 2, wherein in step (b), as the monomer, vinyl chloride alone, or vinyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth). ) A method comprising using a mixture of vinyl chloride and a monomer selected from the group consisting of acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethylene, propylene, and mixtures thereof. . The method of claim 1 or 2, wherein the content of the acrylic copolymer in the vinyl chloride-based resin is 4 to 20% by weight of the vinyl chloride-based resin. A process according to claim 1 or 2, wherein step (b) is carried out by suspension polymerization. 3. The partially saponified vinyl acetate polymer according to claim 1 or 2, wherein the saponification degree is 70 to 90 mol% and the viscosity of the 4 wt% aqueous solution is 30 to 60 cP, the viscosity of the 2 wt% aqueous solution. A suspension stabilizer selected from the group consisting of propyl cellulose having a weight of 50 to 1,000 cP and carboxylated cellulose having a viscosity of 50 to 1,000 cP in a 2% by weight aqueous solution. A process according to claim 10, wherein the suspension stabilizer is used in an amount of 0.2 to 5 parts by weight relative to 100 parts by weight of the total monomers used in step (b). The method according to claim 10, wherein the suspension stabilizer is introduced into the reactor when the reaction conversion rate is 5 to 50% after initiation of the graft copolymerization reaction of step (b).