KR101676087B1 - Method for preparing PVC comprising control heat aids of reflux condenser - Google Patents

Abstract

The present invention relates to a process for producing a vinyl chloride resin comprising a reflux condenser heat-releasing auxiliary, wherein the specific carboxylic acid-modified vinyl alcohol polymer is contained as a heat-releasing auxiliary according to the amount of heat of the reflux condenser, Provided is a method for producing a vinyl chloride resin having a high particle size distribution and a reduced scale formation and a large particle size while providing excellent surface activity and dry foam inhibiting effect by including the vinyl alcohol polymer as a heat release aid according to the amount of heat of the reflux condenser Can,

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a vinyl chloride resin including a reflux condenser heat-

The present invention relates to a process for producing a vinyl chloride resin comprising a reflux condenser heat-releasing auxiliary, and more particularly, to a process for producing a vinyl chloride resin, which comprises a specific carboxylic acid-modified vinyl alcohol polymer as a heat- The present invention relates to a method for producing a vinyl chloride resin having a high particle size distribution while reducing scale and large particle generation while providing a dry foam inhibiting effect.

Since polyvinyl chloride has proven to be soft or hard as well as chemically resistant or electrically insulating, it has been used as a wide range of molding materials throughout the range.

PVC resins are prepared on a plant basis by suspension polymerization from vinyl chloride monomers, the vinyl chloride monomers being polymerized in the presence of a dispersant in a liquid phase using an initiator. Factors that affect the physical properties (quality) of PVC resin when it is polymerized by suspension polymerization include the rate of polymerization, the ratio of water to monomer (vinyl chloride), the type and amount of polymerization temperature initiator, the type of reactor, , And dispersant types. Among them, the effect depending on the kind of the dispersant has a large weight.

In general, polyvinyl alcohol polymers are widely used as dispersants for suspension polymerization and emulsion polymerization of vinyl compounds, and have been particularly useful for suspension polymerization of polyvinyl chloride.

However, the degree of saponification may also cause scale formation on the reflux condenser due to foam generation depending on the amount of injection and the time of injection, which may result in non-uniform particle formation due to incorporation during polymerization and quality of product due to the occurrence of fish eyes. If a reflux condenser is not used to prevent this, the scale due to the foam generation can be prevented, but the polymerization time may be prolonged and the productivity may be lowered.

The following prior art has been proposed as a method for preventing the quality deterioration described above.

Patent Document 1: JP-A-7-179507

Patent Document 2: JP-A-7-18007

Patent Document 3: JP-A-8-73512

Patent Document 4: JP-A-10-1503

Patent Document 5: JP-A-2001-122910

Patent Document 6: Japanese Laid-Open Patent Publication No. 11-116630

Patent Document 7: JP-A-55-137105

Patent Document 8: Korean Patent Laid-Open Publication No. 2009-0018051

Patent Document 9: Korean Patent Publication No. 0808327

In the methods disclosed in the above-mentioned prior art documents 1, 2, 3, 4 and 5, the polyvinyl alcohol polymer having no upper limit of 25% or more in the degree of saponification is introduced at a polymerization conversion rate of 5% to 90% There was a problem of productivity because it tried to reduce the foam generation but the effect was not great and the reflux condenser was not used.

In order to improve this, Patent Documents 6 and 7 propose a polyvinyl alcohol-based polymer partly, sequentially or sequentially, at a polymerization conversion rate of 5% to 90%, but the foam inhibiting effect is not remarkable and the scale generation amount is increased .

In Patent Documents 8 and 9, a modified polyvinyl alcohol polymer containing a double bond or a carbonyl group in its side chain was prepared and used in place of the polymer in order to increase the effect of the dispersing agent. However, It was not enough to effectively cope with the occurrence of scale.

Accordingly, the present invention provides a method for producing a vinyl chloride resin having a high particle size distribution by reducing a scale and generation of large particles while providing a specific surface heat activator and a dry foam inhibiting effect by including a specific heat assistant in accordance with an amount of heat of a reflux condenser .

According to the present invention, in the production of a vinyl chloride resin under the preparation of a vinyl chloride monomer, an initiator and a protective colloid in a suspension polymerization reactor equipped with a reflux condenser,

Wherein the heat removal auxiliary agent of the reflux condenser is charged at a point of time when the amount of heat generated by the reflux condenser is 5% or more of the total amount of heat of polymerization.

Further, according to the present invention,

The bubble phenomenon is suppressed by the above-described method, and high-quality vinyl chloride resin obtained by non-uniform particle generation due to scale incorporation and reduction in the amount of fish eye is provided.

Industrial Applicability According to the present invention, it is possible to provide a production method which is effective for suspension polymerization or emulsion polymerization used in polymerization of vinyl chloride or the like, but has a great effect particularly when used in suspension polymerization, It is possible to achieve an effect of improving a wide particle size distribution, a non-uniform particle shape, and a decrease in workpiece property due to scale, which are caused by the shortage of time and productivity.

Hereinafter, the present invention will be described in more detail.

More specifically, the present invention relates to a method for producing a vinyl chloride resin in a suspension polymerization reactor equipped with a reflux condenser, wherein the heat release aid of the reflux condenser is a copolymer of vinyl chloride monomer, initiator and protective colloid, By weight based on the total weight of the vinyl chloride resin.

The term " heat removal aid " used in the present invention refers to a polymer that assists the heat-generating ability of a reflux condenser provided in a suspension polymerization reactor unless otherwise specified.

The heat removal aid of the reflux condenser may be, for example, one or more times at a time when the amount of heat generated by the reflux condenser is 5 to 90%, 10 to 50%, or 15 to 35% of the total heat of polymerization.

The heat removal aid of the reflux condenser may be added in an amount of 0.005 to 1 part by weight, 0.005 to 0.5 part by weight, or 0.01 to 0.1 part by weight based on 100 parts by weight of the vinyl chloride monomer. The higher the amount of heat generated by the reflux condenser, the greater the amount of foam generated.

The heat removal aid for the reflux condenser may be one prepared by ester bonding a raw polymer to a carboxylic acid or a carboxylic anhydride having an unsaturated double bond.

As a specific example of the raw material polymer, the degree of saponification may be 50 mol% or more and the degree of polymerization may be within a range of 200 to 4,000.

As another example, the starting polymer may have a degree of saponification of 60 to 90 mol%, or 72 to 88 mol%, and the degree of polymerization may be in the range of 500 to 3,000.

The raw material polymer may be, for example, a cellulose derivative such as methyl cellulose, carboxymethyl cellulose hydroxypropyl cellulose, or a water-soluble polymer such as polyvinyl alcohol.

Examples of the carboxylic acid or carboxylic acid anhydride having an unsaturated double bond include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, propinic acid, 2-pentenoic acid, 4-pentenoic acid, 2-heptenoic acid, , Myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, bacosenic acid, valoleic acid, erucic acid, norbornic acid, linoleic acid, eleostearic acid, stearidonic acid, arachidonic acid, eicosapentaenoic acid, Unsaturated monocarboxylic acids such as dodecanoic acid, docosahexaenoic acid and sorbic acid; Unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid; Unsaturated carboxylic anhydrides such as maleic anhydride, fumaric anhydride, itaconic anhydride, citraconic anhydride; Unsaturated carboxylic acid alkyl esters such as acrylic acid alkyl esters, methacrylic acid alkyl esters, and crotonic acid alkyl esters; Unsaturated dicarboxylic acid monoesters such as maleic acid monoalkyl esters, fumaric acid monoalkyl esters, itaconic acid monoalkyl esters; Unsaturated dicarboxylic acid diesters such as maleic acid dialkyl ester, fumaric acid dialkyl ester, and itaconic acid dialkyl ester. Such a carboxylic acid can be used as a salt. The carboxylic acid or the above-mentioned salts may be used singly or in combination of two or more.

The unsaturated double bond-containing carboxylic acid or carboxylic acid anhydride may be used by swelling in a solvent such as methanol or water.

As a specific example, 1 to 10 parts by weight of a carboxylic acid or carboxylic acid anhydride having an unsaturated double bond, based on 100 parts by weight of the raw material polymer, is mixed with 100 to 300 parts by weight The solvent is swelled for about 1 to 3 hours and then dried under reduced pressure at a temperature ranging from room temperature to 40 ° C. for 12 to 24 hours to remove the solvent. The solvent is removed under an inert (nitrogen or the like) atmosphere at 100 to 150 ° C. or 110 to 130 ° C. for 4 hours or less Heat treatment is performed for 1 to 4 hours to obtain a heat-generating auxiliary which is denatured by ester bonding.

The amount of modification of the starting polymer by the carboxylic acid per monomer unit is, for example, in the range of 0.3 to 50 mol%, 0.8 to 25 mol%, or 1.0 to 10 mol%, and the amount of modification is determined by FT- Can be calculated by measurement.

Examples of the vinyl compound to be subjected to the suspension polymerization include vinyl halides such as vinyl chloride; Vinyl esters such as vinyl acetate and vinyl propionate; Acrylic acid, methacrylic acid, esters and salts thereof; Maleic acid, fumaric acid, esters and anhydrides thereof; Styrene, acrylonitrile, vinylidene chloride, vinyl ether, and the like. Of these, particularly preferred is vinyl chloride. It is possible to copolymerize not only vinyl chloride but also vinyl chloride. Examples of the copolymerizable monomer include vinyl esters such as vinyl acetate and vinyl propionate; Olefins such as ethylene and propylene; Vinyl ethers such as lauryl vinyl ether and isobutyl vinyl ether; Maleic anhydride; Acrylonitrile; Styrene; Vinylidene chloride; And other monomers copolymerizable with vinyl chloride.

The polymerization temperature is generally determined by the degree of polymerization of the resin. In the present invention, the polymerization temperature may be 30 to 80 ° C. Specific examples thereof include 61 to 65 ° C for a number average degree of polymerization of 800, In the range of 55 to 60 ° C, and in the case of the number average degree of polymerization of 700 products, in the range of 66 to 70 ° C.

As the polymerization initiator, usability or water solubility can be used. Examples of the oil-soluble initiator include α, α'-bis (neotecanoylperoxy) diisopropylbenzene, cumene peroxyneotecanoate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, , 1,3,3-tetramethylbutyl peroxyneodecanoate, bis (4-t-butylcyclohexyl) peroxy dicarbonate, 1-cyclohexyl-1-methylethyl peroxyneodecanoate, 2-ethylhexyl peroxy dicarbonate, t-hexyl peroxyneodecanoate, dimethoxy butyl peroxy dicarbonate, bis (3-methyl-3-methoxybutyl ) Peroxydicarbonate, t-butyl peroxyneodecanoate, and t-hexyl peroxypivalate, and 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis Azo compounds such as azobis (isobutyronitrile) and dimethyl 2,2'-azobis (isobutyrate). Examples of the water-soluble initiator include potassium persulfate, ammonium persulfate, hydrogen peroxide, cumene hydroperoxide, and the like. Such an oil-soluble or water-soluble initiator may be used alone or in combination of two or more.

The initiator is appropriately selected under the polymerization temperature determined according to the degree of polymerization of the resin, and used at the beginning of the polymerization. The content of the initiator may be the same as that of the initiator used in the conventional polymerization. For example, it may be within the range of 0.02 to 0.3 parts by weight based on 100 parts by weight of the vinyl chloride monomer.

The protective colloid assistant to be added at the start of the reaction is used to obtain stable particles while stably maintaining the process of suspension polymerization of the vinyl chloride monomer. For example, a protective colloid aid having a hydration degree of 31 to 98% by weight and a 4% A vinyl alcohol resin having a viscosity of 10 to 60 cps, a cellulose and an unsaturated organic acid having a methoxy group content of 15 to 40% by weight, a hydroxyl group content of 3 to 20% by weight and a 2% aqueous solution viscosity measured at room temperature of 10 to 20,000 cps May be used in an amount of 0.03 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer.

For reference, liquid droplet stability is lowered below the lower limit value, and when the upper limit value is exceeded, the fish eye characteristic can be remarkably reduced by forming the beads.

As a specific example, the protective colloid preparation may be a polyvinyl alcohol resin having a degree of hydration of 85 to 98% (high water-solubility resin), a vinyl alcohol resin having a water-solubility of 62 to 82% (water-insolubility resin) % Of a polyvinyl alcohol resin (low hydration resin), and a cellulose suspension stabilizer.

The blending ratio of the high-, middle-, and low-hydration resins is adjusted according to the target physical properties. In the present invention, it may be preferable to mix and use three kinds of high-, medium- and low-hydration resins.

As another example, the protective colloid preparation may contain 0.04 parts by weight of a polyvinyl alcohol resin having a degree of hydration of 85 to 98% (high water-solubility resin), 0.05 parts by weight of a vinyl alcohol resin having a degree of hydration of 62 to 82% And 0.02 parts by weight of a vinyl alcohol resin (low hydration resin) having a hydration degree of 50 to 60% and 0.01 part by weight of a cellulose suspension stabilizer.

The unsaturated organic acid may be at least one selected from acrylic acid polymer, methacrylic acid polymer, itaconic acid polymer, fumaric acid polymer, maleic acid polymer, succinic acid polymer and gelatin.

Further, a plurality of additives such as a reactive agent, a pH adjuster, a crosslinking agent, an antistatic agent, a stabilizer, a buffer and the like may be added as needed. The total amount of the antistatic agent may be 1 part by weight or less based on 100 parts by weight of the vinyl chloride monomer.

According to the production method of the present invention, the productivity of the vinyl resin can be improved because the foam reducing effect and the dispersant surface activity generated throughout the polymerization are increased, and the generation of scale is reduced, It is possible to provide a high-quality vinyl-based resin.

The following examples illustrate the present invention and are not intended to limit the scope thereof.

Production Example 1 (Heat-generating auxiliary agent production 1)

100 parts of polyvinyl alcohol polymer powder having a degree of polymerization of 2400 and a degree of saponification of 88 mol% and 5 parts of maleic acid were dissolved in 200 parts of methanol and swollen for 2 hours, followed by further drying at 40 DEG C under reduced pressure for 24 hours to sufficiently remove the solvent. And the mixture was heated at 130 캜 under a nitrogen atmosphere for 2 hours to prepare a modified polyvinyl alcohol polymer as a heat removal aid.

Manufacturing example  2 to 11

The same procedure as in Preparation Example 1 was repeated except that the maleic acid and heating conditions were changed to the conditions shown in Table 1 below.

Example  One( suspension  Polymerization of vinyl chloride Manufacturing 1 )

100 parts by weight of a vinyl chloride monomer, 130 parts by weight of deionized water, 0.04 parts by weight of a polyvinyl alcohol having a degree of saponification of 72% as a protective colloid preparation, and 0.02 parts by weight of 55% polyvinyl alcohol were added to a suspension polymerization reactor equipped with a reflux condenser having a capacity of 100 L Respectively.

Then 0.05 part by weight of t-butyl peroxyneodecanoate (BND) was added as an initiator and the reactor was depressurized and air and nitrogen were removed while stirring.

Thereafter, the reaction was carried out while maintaining the target polymerization temperature at 64 ° C. At the time when the amount of heat generated in the reflux condenser in the initial stage of the reaction was 5% of the total amount of the polymerized heat, 0.02 part of the heat assistant of Production Example 1 was added.

When the pressure reached 8.7 Kgf / cm < 2 >, the reactor was cooled and 0.04 part by weight of an antioxidant was added to stop the reaction, and the unreacted vinyl chloride monomer was recovered through deaeration to recover the vinyl chloride resin slurry. The polymer slurry was washed and dried overnight to obtain vinyl chloride polymer particles having a degree of polymerization of 800.

Vinyl chloride polymer particles were obtained in the same manner as in Example 1 except that the heat-generating auxiliary agent of Production Example 1 was replaced with the heat-generating auxiliary agent of Production Examples 2 to 11, and physical properties were measured by the following method, Are summarized together in Table 1 below.

≪ Evaluation of physical properties &

1. Volumetric density : The time from initiation of the initiator to the end of the reaction was measured

2. Processing Whiteness : 1 part by weight of a complex stabilizer (WPS-60, a binder stabilizer, Songwon Industries) and 1.5 parts by weight of a processing aid (PA-822, acrylic processing aid, LG Chem) were added to 100 parts by weight of the vinyl chloride resin 1 part by weight of titanium oxide and 0.3 part by weight of a blowing agent were put and rolled at 180 캜 for 5 minutes to obtain a sheet having a thickness of 0.5 mm.

Then, the whiteness (W.I) value was measured using NR-3000 manufactured by Nippon Denshoku Co., Ltd. The results are summarized in Tables 1 and 2. The thermal stability can be measured from the whiteness value. The higher the value, the better the thermal stability.

3. Fish eye (fish - eye) can be vinyl-based resin 100 parts by weight, using a DOP 45 parts by weight of barium stearate, 0.1 part by weight of tin based stabilizer, 0.2 parts by weight of 6-inch roll of carbon black 0.1 parts by weight of 140 ℃ chloride by kneading a mixture of 4 minutes, and making a sheet having a thickness of 0.3 mm, 400 cm ² of the sheet The number of white transparent particles in the sample.

4. Measurement of particle size and particle size distribution : The obtained resin was measured for particle size using a HELOS particle size analyzer manufactured by Sumpatec, and the value of the span at that time was defined as a particle size distribution. The lower the value of the span, the smaller the deviation.

division Type of carboxylic acid Heating temperature
(° C) Heating time
(h) Volume Density (g / cm3) Process Whiteness (Ea) Particle size
(탆) Particle size distribution
(span) Production Example 1 Maleic acid 130 2 0.58 68 6 142 0.57 Production Example 2 Maleic acid 100 2 0.59 68 5 144 0.64 Production Example 3 Maleic acid 130 One 0.59 68 5 143 0.61 Production Example 4 Maleic acid 130 4 0.57 67 7 146 0.57 Production Example 5 Maleic acid 150 2 0.56 67 11 148 0.58 Production Example 6 Fumaric acid 110 2 0.58 66 6 134 0.61 Production Example 7 Fumaric acid 130 2 0.57 67 7 136 0.59 Production Example 8 Acrylic acid 110 2 0.59 67 7 142 0.62 Production Example 9 Acrylic acid 130 2 0.58 68 5 140 0.59 Production Example 10 Chromic acid 110 2 0.56 66 9 139 0.57 Production Example 11 Chromic acid 130 2 0.57 67 8 134 0.61

Example  2 to 9

The same steps as in Example 1 were repeated except that the injection timing and the amount of the heat-transfer auxiliary agent were changed in the same manner as in Table 1 below.

division Feeding time (% heat of reflux cooler) input
(Parts by weight) Volume Density (g / cm3) Process Whiteness (Ea) Particle size
(탆) Particle size distribution
(span) Example 1 5 0.02 0.58 68 6 142 0.57 Example 2 20 0.005 0.57 68 8 141 0.59 Example 3 20 0.05 0.58 69 6 142 0.57 Example 4 20 0.2 0.58 68 7 135 0.61 Example 5 20 0.6 0.58 67 7 139 0.62 Example 6 40 0.4 0.59 68 6 134 0.59 Example 7 60 0.4 0.59 67 8 136 0.59 Example 8 70 0.5 0.58 67 8 134 0.60 Example 9 80 0.5 0.58 67 9 136 0.64

As shown in Tables 1 and 2, it was confirmed that the produced vinyl chloride polymer maintained a whiteness degree while maintaining a high bulk density. In addition, it was confirmed that the amount of foams was reduced by injecting the heat releasing auxiliary of the reflux condenser at the time of foam generation, and it was confirmed that the fishy eye was improved and by increasing the surface activity, coarse particles could be reduced and particles having a high particle size distribution could be obtained.

Comparative Example  One

The same procedure as in Example 1 was repeated except that the raw material polymer was used without modification in place of the heat removal aid in Example 1, and the measurement results are summarized in Table 3 below.

Comparative Example  2 to 5

The same procedure as in Example 1 was repeated except that the raw material polymer was used in the same manner as in Example 1 without modifying the raw material polymer and the reaction was carried out under the heating conditions shown in Table 3. The measurement results are summarized in Table 3 below.

Comparative Example  6 to 10

The same procedure as in Example 1 was repeated except that suspension polymerization was carried out under the heating conditions shown in Table 3 in Example 1, and the measurement results are summarized in Table 3 below.

division Whether carboxylic acid is injected Heat treatment temperature (캜) Heat treatment time (h) Volume Density (g / cm3) Process Whiteness (Ea) Particle size
(탆) Particle size distribution
(span) Comparative Example 1 No entry 0 0 0.57 68 10 149 0.68 Comparative Example 2 100 One 0.52 62 22 158 0.65 Comparative Example 3 130 One 0.52 61 19 156 0.71 Comparative Example 4 130 2 0.51 61 21 158 0.69 Comparative Example 5 150 2 0.50 61 28 162 0.74 Comparative Example 6 input 0 0 0.49 61 52 171 0.93 Comparative Example 7 80 2 0.50 63 42 168 0.88 Comparative Example 8 100 6 0.52 64 44 159 0.73 Comparative Example 9 130 5 0.52 64 38 162 0.81 Comparative Example 10 160 2 0.53 63 33 166 0.79

As shown in Table 3, in Comparative Examples 2 to 5, when the heat treatment is performed without the addition of carboxylic acid, the function as a dispersant is lowered, so that the volume density, process whiteness, Uniform particles could not be obtained. In addition, in Comparative Examples 6 to 10, in which the heat treatment was performed at a temperature of 100 ° C or lower or more than 4 hours at a temperature of 150 ° C or higher, even when a carboxylic acid was added, no esterification reaction proceeded and no change in physical properties was observed. And it was confirmed that the dispersion degree with respect to the solvent was lowered. .

Comparative Example  11

The same procedure as in Example 1 was repeated except that the heat removal aid was added at a point of 0% of the total amount of heat of polymerization after the amount of heat of the reflux condenser at the beginning of the polymerization in Example 1, Respectively.

Comparative Example  12 to 17

The same procedure as in Example 1 was repeated except that the heat removal auxiliary agent was added in accordance with the polymerization conversion rate shown in Table 4 instead of the heat amount of the reflux condenser in Example 1, Respectively.

division Time of input
(% Conversion of polymerization) input
(Parts by weight) Volume Density (g / cm3) Process Whiteness (Ea) Particle size
(탆) Particle size distribution
(span) Comparative Example 11 0 0.04 0.58 67 12 139 0.59 Comparative Example 12 5 0.02 0.57 66 9 142 0.62 Comparative Example 13 20 0.02 0.54 68 7 144 0.59 Comparative Example 14 20 0.04 0.58 67 6 144 0.61 Comparative Example 15 40 0.04 0.56 67 8 138 0.55 Comparative Example 16 60 0.04 0.54 67 11 142 0.59 Comparative Example 17 80 0.1 0.57 66 9 139 0.57

As shown in Table 4, the volume density, the processed whiteness, the fineness, the particle diameter, and the particle size distribution were improved to standard or higher when the injection timing of the heat removal auxiliary agent was changed according to the polymerization conversion time point. There is a difficulty in standardization because there is a variation in each polymerization reactor such as a heat-removing ability, a size and a shape of a polymerization reactor, and a performance of a heating system. In particular, according to Comparative Example 11 put in before the initiation of the polymerization conversion, it was difficult to obtain the effect of suppressing foam generation, and it was confirmed that the amount of fishy eye was increased.

Therefore, according to the present invention, it is possible to improve the productivity of the vinyl resin by obtaining a high volume density and uniform particles by increasing the foam reducing effect and the dispersant surface activity generated throughout the polymerization, and by reducing the generation of scale, It is possible to provide a high-quality vinyl-based resin.

Claims (11)

In the production of vinyl chloride resin under the preparation of vinyl chloride monomer, initiator and protective colloid in a suspension polymerization reactor equipped with a reflux condenser,
The heat removal aid of the reflux condenser is charged at a time point when the amount of heat generated by the reflux condenser is 20 to 80% of the total amount of heat of polymerization, and 0.2 to 1 part by weight based on 100 parts by weight of the vinyl chloride monomer, Wherein the ester bond is carried out at 100 to 150 ° C for not more than 4 hours, the raw polymer being selected from the group consisting of methylcellulose, carboxymethylcellulose hydroxypropylcellulose and poly Vinyl alcohol. ≪ RTI ID = 0.0 > 11. < / RTI >
delete delete delete The method according to claim 1,
Wherein the raw material polymer has a degree of saponification of 50 mol% or more and a polymerization degree of 200 to 4,000.
delete The method according to claim 1,
The carboxylic acid or carboxylic acid anhydride having an unsaturated double bond is an unsaturated monocarboxylic acid; Unsaturated dicarboxylic acids; Unsaturated carboxylic acid anhydrides; Unsaturated carboxylic acid alkyl esters; Unsaturated dicarboxylic acid monoesters; And unsaturated dicarboxylic acid diesters; Wherein the vinyl chloride resin is a vinyl chloride resin.
The method according to claim 1,
Wherein the unsaturated double bond-containing carboxylic acid or carboxylic acid anhydride is used by swelling in a solvent.
delete The method according to claim 1,
Wherein the raw material polymer has an amount of modification by a carboxylic acid per monomer unit of 0.3 to 50 mol%.
A high quality vinyl chloride resin obtained by the method of any one of claims 1, 5, 7, 8 or 10.