JP6800407B2 - Manufacturing method of vinyl chloride resin seed - Google Patents

Description

The present invention relates to a method for producing a vinyl chloride resin seed containing a polymerization initiator used when producing a vinyl chloride resin for paste processing by a seed polymerization method, and more particularly, the polymerization initiator. The present invention relates to a method for producing a vinyl chloride resin seed, which enables stable polymerization by significantly shortening the polymerization time when producing a vinyl chloride resin for paste processing in an aqueous medium in the presence of the present. .. Further, the vinyl chloride resin for paste processing obtained by using the vinyl chloride resin seed may be referred to as a vinyl chloride resin sol for paste processing prepared by dispersing it in a plasticizer (hereinafter, simply referred to as a paste PVC sol). ) Is a vinyl chloride-based resin for paste processing that has little change with time, has excellent mechanical strength at low temperatures, and has excellent properties as a coating material, particularly an automobile underbody coating material and an automobile sealant material.

As a method for producing a vinyl chloride resin for paste processing (hereinafter abbreviated as paste vinyl chloride), generally, a vinyl chloride monomer or a vinyl chloride monomer and a monomer copolymerizable therewith are used in a polymerization can. In the presence of a polymerization initiator, the mixed monomer of the above is subjected to a polymerization method such as a fine suspension polymerization method, an emulsion polymerization method, a seed fine suspension polymerization method, a seed emulsion polymerization method in an aqueous medium, and the temperature inside the polymerization can is increased. The polymerization reaction is advanced while maintaining the temperature at a predetermined temperature, and as the polymerization conversion rate increases, the unreacted component of the charged monomer decreases and the pressure inside the polymerization can begins to decrease, which corresponds to the desired polymerization conversion rate. Examples thereof include a production method in which the polymerization reaction is terminated when the pressure inside the polymerization can is reached, a paste vinyl chloride latex is produced, and the latex is dried to obtain paste vinyl chloride.

In such a method for producing a paste PVC, as a method for improving the productivity of the paste PVC, a method of increasing the addition amount of the polymerization initiator and shortening the polymerization time can be mentioned. However, when the amount of the polymerization initiator added is increased, agglomeration of the paste PVC particles during the polymerization occurs, a large number of coarse particles are generated, stable polymerization becomes difficult, and productivity and quality deteriorate. there were.

Therefore, as a method for producing a vinyl chloride-based polymer in which the reaction time does not become long even if the amount of the polymerization initiator is reduced, a perester compound or a percarbonate compound is used as the polymerization initiator, and the polymerization conversion rate is 20% before polymerization. A production method of adding a water-soluble peroxide, a hydroperoxide-based oil-soluble polymerization initiator, and a water-soluble reducing agent has been proposed (see, for example, Patent Document 1).

Further, as a method for producing a paste PVC having a high reactivity ratio between a vinyl chloride monomer and a monomer copolymerizable therewith, the polymerization time is significantly shortened, and a production method in which a vinyl chloride-based monomer is added in portions Has been proposed (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 10-338701.

JP-A-2009-221335.

However, in the method of Patent Document 1, although the effect of improving the polymerization rate is discussed, it relates to a method for producing a paste PVC, particularly an automobile underbody coat material and a vinyl chloride resin for paste processing as an automobile sealant material. is not. In addition, although the effect of improving the polymerization rate has been discussed in Patent Document 2, the quality of the obtained vinyl chloride resin for paste processing, particularly the stability of the paste PVC sol against changes over time, has been investigated. It wasn't.

As described above, the methods studied so far can shorten the polymerization time, but they have not been studied at all as the obtained paste PVC, especially the automobile underbody coating material and the automobile sealant material. It was.

In addition, in the seed polymerization of paste PVC, no report has been made on vinyl chloride-based resin seeds, which can significantly shorten the polymerization time and enable stable polymerization.

Therefore, the present invention provides a vinyl chloride-based resin seed that enables a significant reduction in the polymerization time when the paste PVC is produced by seed polymerization and also enables stable polymerization. It is an object of the present invention, and further, by using the vinyl chloride resin seed, a method for efficiently producing a paste PVC which can be applied as an automobile underbody coating material and an automobile sealant material is provided. It is also the purpose.

As a result of diligent studies to solve the above problems, the present inventors produce a vinyl chloride resin seed under specific conditions, and use the vinyl chloride resin seed in the seed polymerization. As a result, they have found that it is possible to stably produce a paste PVC that can be applied as an automobile underbody coating material and an automobile sealant material in a short time, and have completed the present invention.

That is, in the present invention, a vinyl chloride monomer, an emulsifier, a polymerization initiator, and a chain transfer agent are added to an aqueous medium, mixed, homogenized, and then polymerized to carry out a polymerization initiator-containing vinyl chloride resin seed. Is characterized by using 4 to 10 parts by weight of a polymerization initiator with respect to 100 parts by weight of a vinyl chloride monomer and further adding 0.5 to 5 parts by weight of an emulsifier after completion of the polymerization reaction. The present invention relates to a method for producing a vinyl-based resin seed, and a method for producing a paste PVC, which comprises performing seed polymerization of a vinyl chloride-based monomer in the presence of the vinyl chloride-based resin seed.

Hereinafter, the present invention will be described in detail.

In the method for producing a vinyl chloride resin seed of the present invention, a vinyl chloride monomer, an emulsifier, a polymerization initiator, and a chain transfer agent are added to an aqueous medium, mixed, homogenized, and then polymerized and polymerized. When producing a vinyl chloride resin seed containing an initiator, 4 to 10 parts by weight of the polymerization initiator is used with respect to 100 parts by weight of the vinyl chloride monomer, and 0.5 to 5 parts by weight of the emulsifier is further added after the completion of the polymerization reaction. Part is added. Then, by performing seed polymerization of the vinyl chloride-based monomer in the presence of the vinyl chloride-based resin seed, the paste PVC, which can be applied particularly as an automobile underbody coating material and an automobile sealant material, is stabilized in a short time. It is possible to manufacture the product.

The vinyl chloride-based resin seed and paste PVC obtained by the present invention are vinyl chloride-based monomers or vinyl chloride-based monomers which are mixed monomers of vinyl chloride monomers and monomers capable of copolymerizing with them. The vinyl chloride-based resin seed is a vinyl chloride-based resin containing a polymerization initiator capable of polymerizing a vinyl chloride-based monomer. As a method for producing a paste PVC using the vinyl chloride resin seed, any polymerization method can be used as long as the vinyl chloride resin seed can be used, and as a general method, it can be used. For example, a seed polymerization method by a seed emulsification polymerization method, a seed fine suspension polymerization method, or the like can be mentioned.

Examples of the monomer that can be copolymerized with the vinyl chloride monomer at that time include vinyl esters such as vinyl acetate, vinyl propionate, vinyl myristate, vinyl benzoate; acrylic acid, methacrylic acid, maleic acid, and fumal. Unsaturated carboxylic acids such as acids or their anhydrides; acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, malein Unsaturated carboxylic acid esters such as acid esters, fumaric acid esters and methacrylic acid esters; vinyl ethers such as vinyl methyl ether, vinyl amyl ether and vinyl phenyl ether; monoolefins such as ethylene, propylene, butene and penten; vinylidene chloride , Styrene and its derivatives, acrylonitrile, methacrylic acid and the like, and these can be used in two or more kinds.

In the method for producing a vinyl chloride resin seed of the present invention, a vinyl chloride monomer, an emulsifier, a polymerization initiator, and a chain transfer agent are added to an aqueous medium, mixed, homogenized, and then polymerized and polymerized. When producing a vinyl chloride resin seed containing an initiator, 4 to 10 parts by weight of the polymerization initiator is used with respect to 100 parts by weight of the vinyl chloride monomer, and 0.5 to 5 parts by weight of the emulsifier is further added after the completion of the polymerization reaction. Part is added.

Examples of the emulsifier at that time include alkyl sulfates such as sodium lauryl sulfate and sodium myristyl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate and potassium dodecylbenzenesulfonate, sodium dioctyl sulfosuccinate and dihexyl sulfosuccinic acid. Anionic surfactants such as sulfosuccinates such as sodium, fatty acid salts such as ammonium laurate, potassium stearate, polyoxyethylene alkyl sulfates, polyoxyethylene alkylaryl sulfates; sorbitan monooleate, polyoxyethylene Use one or more of conventionally known substances such as sorbitan esters such as sorbitan monostearate, nonionic surfactants such as polyoxyethylene alkylphenyl ethers and polyoxyethylene alkyl esters; Alkylbenzenesulfonate is preferable because it makes it possible to produce a vinyl chloride resin seed capable of producing a paste vinyl chloride having excellent quality, and as a specific example of the alkylbenzenesulfonate. Can be mentioned as sodium dodecylbenzenesulfonic acid salt, potassium dodecylbenzenesulfonic acid salt, ammonium dodecylbenzenesulfonic acid salt, triethanolammonium dodecylbenzenesulfonic acid salt and the like. Then, in the method for producing a vinyl chloride resin seed of the present invention, an emulsifier typified by alkylbenzene sulfonate is further added after the polymerization reaction of the vinyl chloride resin seed is completed, and the emulsifier is added to the vinyl chloride resin seed. By adding after the completion of the polymerization reaction of, the aggregation of vinyl chloride resin seeds and the formation of coarse particles can be suppressed. Further, the amount of the emulsifier added at that time is 0.5 to 5 parts by weight with respect to 100 parts by weight of the vinyl chloride monomer. When the amount of the emulsifier to be additionally added is less than 0.5 parts by weight, the vinyl chloride resin seeds are aggregated. On the other hand, when the amount of emulsifier exceeds 5 parts by weight, the amount of emulsifier contained in the paste vinyl chloride obtained in the presence of the vinyl chloride resin seed is large, and the stability of the paste PVC sol with respect to the change in viscosity with time deteriorates. It becomes PVC.

The polymerization initiator may be any one called a polymerization initiator, and vinyl chloride resin seeds applied to the seed emulsion polymerization method are usually water-soluble typified by potassium persulfate, ammonium persulfate and the like. Initiators can be mentioned, and if it is a vinyl chloride resin seed applied to the seed microsuspension polymerization method, it is usually an azo compound typified by azobisisobutyronitrile, lauroyl peroxide, t-butylperoxypivalate. , Diacyl peroxide, peroxyester, peroxide typified by peroxydicarbonate, etc., oil-soluble initiators and the like can be mentioned. In particular, an oil-soluble polymerization initiator is preferable because it enables the production of vinyl chloride-based resin seeds that can be applied to the seed fine suspension polymerization method, which is an efficient method for producing paste vinyl chloride. In particular, an oil-soluble polymerization initiator that is soluble in vinyl chloride-based monomers and has a 10-hour half-life temperature of 30 to 70 ° C., such as isobutyryl peroxide, 3,3,5-trimethylhexanoyl peroxide, and octanoyl peroxide. , Lauryl peroxide, stearoyl peroxide, succinic acid peroxide and other diacyl-based polymers are preferable, and lauryl peroxide is further preferable. The polymerization initiator is one in which 4 to 10 parts by weight is added to 100 parts by weight of the vinyl chloride monomer. Here, if it is less than 4 parts by weight, the production efficiency when the paste PVC is produced in the presence of the obtained seed becomes poor. On the other hand, if it exceeds 10 parts by weight, agglomeration or the like is likely to occur during the production of the paste PVC, and the method for producing the paste PVC is inferior in quality.

Examples of the chain transfer agent include halogen-based hydrocarbons such as trichloroethylene and carbon tetrachloride, mercaptones such as 2-mercaptoethanol, octyl 3-mercaptopropionate, and dodecyl mercaptan, and aldehydes such as acetone and n-butyraldehyde. These may be used alone or in combination of two or more. The amount added is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the vinyl chloride monomer.

Examples of the aqueous medium include those belonging to the category called aqueous medium, water, deionized water, distilled water, clean water and the like, and organic as long as they belong to the category called aqueous medium. It may contain a solvent or the like. The amount added is preferably 50 to 200 parts by weight with respect to 100 parts by weight of the vinyl chloride monomer.

The method for producing a vinyl chloride resin seed of the present invention may contain a polymerization aid such as a surfactant and a buffer, and an emulsification aid, and the emulsification aid may be, for example, cetyl alcohol or lauric acid. Examples thereof include higher alcohols such as alcohols, higher fatty acids such as lauric acid, palmitic acid and stearic acid or esters thereof, aromatic hydrocarbons, higher fatty acid hydrocarbons, halogenated hydrocarbons such as chlorinated paraffins, and the like.

Then, in the presence of the obtained vinyl chloride-based resin seed, the vinyl chloride-based monomer is subjected to a seed polymerization method typified by a seed emulsification polymerization method and a seed fine suspension polymerization method to carry out paste vinyl chloride or paste vinyl chloride latex. Can be manufactured.

The seed polymerization method represented by the seed emulsification polymerization method and the seed fine suspension polymerization method at that time is not particularly limited, and a method generally called a seed polymerization method can be mentioned, and chloride at that time can be mentioned. Examples of vinyl-based monomers, emulsifiers, chain transfer agents, aqueous media, polymerization aids, and emulsification aids similar to those described above can be exemplified.

Any method may be used as a method for obtaining the paste PVC from the paste PVC latex which is the aqueous medium dispersion liquid (suspension, emulsion) of the produced paste PVC, and among them, water content from the latex is efficiently used. The method by spray drying is preferable because it can remove. The dryer used for spray drying may be a commonly used dryer, for example, "SPRAY DAYING HANDBOOK" (K. Masters, 3rd edition, 1979, published by George goodwin Limited), p. 121, p. 4. Examples thereof include various spray dryers (for example, Standard chamber, Tall-form nozzle chamber, etc.) shown in FIG. The drying temperature at that time is generally 80 to 200 ° C. at the inlet of the dryer, and 40 to 70 ° C., preferably 45 ° C. to 65 ° C. at the outlet. After drying, the obtained paste PVC is an agglomerate of particles constituting the vinyl chloride resin latex, and is usually in the form of granules having a size of 10 to 150 μm. When the drying outlet temperature exceeds 52 ° C, it is preferable to pulverize the obtained granular paste PVC from the viewpoint of dispersibility in the plasticizer, and when the drying outlet temperature is 52 ° C or less, it remains granular. However, it may be crushed and used.

The vinyl chloride-based resin seed obtained by the present invention can significantly shorten the polymerization time when producing a paste PVC, and the obtained paste PVC is a paste PVC sol prepared by dispersing it in a plasticizer. It is possible to provide a coating material, particularly an automobile underbody coating material and an automobile sealant material, which has little change in viscosity with time, has excellent mechanical strength during low-temperature processing, and has excellent characteristics.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not construed as being limited by these examples.

<Measurement method of thickening rate>
100 parts by weight of diisononyl phthalate (manufactured by J-PLUS Co., Ltd.) and calcium carbonate surface-treated calcium carbonate ((trade name) Viscolite-OS Shiraishi Kogyo Co., Ltd.) with respect to 100 parts by weight of paste vinyl chloride (vinyl chloride-vinyl acetate copolymer) 70 parts by weight and 15 parts by weight of a naphthenic hydrocarbon solvent ((trade name) Exsol D40 manufactured by Tonen General Petroleum Co., Ltd.) were kneaded to obtain a paste vinyl chloride solution. The obtained paste PVC sol was stored at 23 ° C. for 2 hours, and then the viscosity measured with a B8H type rotational viscometer at 23 ° C. and 20 rpm was defined as viscosity A, and the sol was further stored at 40 ° C. for 7 days. After that, the viscosity measured with a B8H type rotational viscometer under the conditions of 40 ° C. and 20 rpm was defined as viscosity B. The viscosity A and the viscosity B were determined by the following formulas to determine the thickening rate of the obtained paste vinyl chloride sol. The thickening rate of 75% or less at that time was evaluated as excellent.

Thickening rate (%) = 100 x (BA) / A
<Method for measuring vinyl acetate monomer residue content>
The vinyl acetate monomer residue (% by weight) (VAc content) contained in the vinyl chloride-vinyl acetate copolymer is a measurement sample formed by mixing 100 mg of paste PVC and 10 mg of potassium bromide and grinding them, and red. It was calculated from the following formula using an external spectrophotometer (manufactured by Shimadzu Corporation, (trade name) FTIR-8100A).

VAc content = (3.73 x B / A + 0.024) x 1.04
A: Abs at the top of the absorption peak due to the in-plane variation of CH near 1430 cm- ¹ . value.
B: Abs at the top of the absorption peak due to C = O expansion and contraction near 1740 cm ^-1 . value.

<Measurement method of average particle size of paste bilatex chloride>
The average particle size of the paste PVC latex is the particle size distribution of the paste PVC obtained under the condition of a refractive index of 1.16 by a laser diffraction / scattering type particle size distribution measuring device (manufactured by HORIBA, Ltd. (trade name) LA-920). The measurement was performed, and the average particle size was measured from the result.

Example 1
990 g of deionized water, 700 g of vinyl chloride monomer, 52.5 g of lauryl peroxide, 2 g of dodecyl mercaptan, and 100 g of 10 wt% sodium dodecylbenzene sulfonate aqueous solution were charged in a 2.5 L autoclave, and the polymerization solution was charged with a homogenizer. After 90 minutes of circulation and homogenization treatment, the temperature was raised to 40 ° C. to proceed with polymerization. The polymerization reaction was stopped when the pressure of the autoclave dropped to 0.3 MPa, 50 g of 10 wt% sodium dodecylbenzenesulfonate was added, and the unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride resin seed. .. The results are shown in Table 1. The obtained latex containing the vinyl chloride resin seed had an average particle size of 0.52 μm.

Then, 500 g of deionized water, 715 g of vinyl chloride monomer and 48 g of vinyl acetate monomer and 8.6 g of 5% aqueous sodium lauryl sulfate in a 2.5 liter autoclave, and the vinyl chloride resin seed obtained as described above. 80 g of latex and 4 g of 0.1% aqueous solution copper sulfate were charged, and then the temperature of this reaction mixture was raised to 35 ° C. to proceed with seed fine suspension polymerization. From the start of the polymerization to the end of the polymerization, 120 g of 5% aqueous sodium lauryl sulfate and 0.05% aqueous ascorbic acid were continuously added, and the polymerization reaction was stopped when the pressure of the autoclave decreased to 0.22 MPa.

The polymerization time at that time was 791 minutes.

Then, the unreacted monomer was recovered to obtain a paste PVC latex. The obtained paste PVC latex was spray-dried with a spray dryer at a hot air inlet temperature of 160 ° C. and an outlet temperature of 55 ° C. to obtain a paste PVC which is a vinyl chloride-vinyl acetate copolymer.

A paste PVC sol was prepared using the obtained paste PVC, and its physical properties were evaluated. The results are shown in Table 2.

Example 2
990 g of deionized water, 700 g of vinyl chloride monomer, 38.5 g of lauryl peroxide, 2 g of dodecyl mercaptan, and 100 g of 10 wt% sodium dodecylbenzene sulfonate aqueous solution were charged in a 2.5 L autoclave, and the polymerization solution was charged with a homogenizer. After 90 minutes of circulation and homogenization treatment, the temperature was raised to 40 ° C. to proceed with the polymerization reaction. The polymerization reaction was stopped when the pressure of the autoclave dropped to 0.3 MPa, and 50 g of 10 wt% sodium dodecylbenzenesulfonate was added to recover the unreacted vinyl chloride monomer to obtain a vinyl chloride resin seed. Obtained. The results are shown in Table 1. The obtained latex containing the vinyl chloride resin seed had an average particle size of 0.53 μm.

Then, 500 g of deionized water, 715 g of vinyl chloride monomer and 48 g of vinyl acetate monomer and 8.6 g of 5% aqueous sodium lauryl sulfate in a 2.5 liter autoclave, and the vinyl chloride resin seed obtained as described above. 80 g of latex and 4 g of 0.1% aqueous solution copper sulfate were charged, and then the temperature of this reaction mixture was raised to 35 ° C. to proceed with seed fine suspension polymerization. From the start of the polymerization to the end of the polymerization, 120 g of 5% aqueous sodium lauryl sulfate and 0.05% aqueous ascorbic acid were continuously added, and the polymerization reaction was stopped when the pressure of the autoclave decreased to 0.22 MPa.

The polymerization time at that time was 797 minutes.

Then, the unreacted monomer was recovered to obtain a paste PVC latex. The obtained paste PVC latex was spray-dried with a spray dryer at a hot air inlet temperature of 160 ° C. and an outlet temperature of 55 ° C. to obtain a paste PVC which is a vinyl chloride-vinyl acetate copolymer.

A paste PVC sol was prepared using the obtained paste PVC, and its physical properties were evaluated. The results are shown in Table 2.

Example 3
990 g of deionized water, 700 g of vinyl chloride monomer, 52.5 g of lauryl peroxide, 2 g of dodecyl mercaptan, and 100 g of 10 wt% sodium dodecylbenzene sulfonate aqueous solution were charged in a 2.5 L autoclave, and the polymerization solution was charged with a homogenizer. After 90 minutes of circulation and homogenization treatment, the temperature was raised to 40 ° C. to proceed with the polymerization reaction. When the pressure of the autoclave dropped to 0.3 MPa, the polymerization reaction was stopped, 100 g of 10 wt% sodium dodecylbenzenesulfonate was added, the unreacted vinyl chloride monomer was recovered, and the vinyl chloride resin seed was obtained. Obtained. The results are shown in Table 1. The obtained latex containing the vinyl chloride resin seed had an average particle size of 0.52 μm.

Then, 500 g of deionized water, 715 g of vinyl chloride monomer and 48 g of vinyl acetate monomer and 8.6 g of 5% aqueous sodium lauryl sulfate in a 2.5 liter autoclave, and the vinyl chloride resin seed obtained as described above. 80 g of latex and 4 g of 0.1% aqueous solution copper sulfate were charged, and then the temperature of this reaction mixture was raised to 35 ° C. to proceed with seed fine suspension polymerization. From the start of the polymerization to the end of the polymerization, 120 g of 5% aqueous sodium lauryl sulfate and 0.05% aqueous ascorbic acid were continuously added, and the polymerization reaction was stopped when the pressure of the autoclave decreased to 0.22 MPa.

The polymerization time at that time was 780 minutes.

Then, the unreacted monomer was recovered to obtain a paste PVC latex. The obtained paste PVC latex was spray-dried with a spray dryer at a hot air inlet temperature of 160 ° C. and an outlet temperature of 55 ° C. to obtain a paste PVC which is a vinyl chloride-vinyl acetate copolymer.

A paste PVC sol was prepared using the obtained paste PVC, and its physical properties were evaluated. The results are shown in Table 2.

Example 4
990 g of deionized water, 700 g of vinyl chloride monomer, 38.5 g of lauryl peroxide, 2 g of dodecyl mercaptan, and 100 g of 10 wt% sodium dodecylbenzene sulfonate aqueous solution were charged in a 2.5 L autoclave, and the polymerization solution was charged with a homogenizer. After 90 minutes of circulation and homogenization treatment, the temperature was raised to 40 ° C. and the polymerization reaction proceeded. When the autoclave pressure reached 0.3 MPa, the polymerization reaction was stopped, and 100 g of 10 wt% sodium dodecylbenzenesulfonate was further added to recover the unreacted vinyl chloride monomer to obtain a vinyl chloride resin seed. .. The results are shown in Table 1. The obtained latex containing the vinyl chloride resin seed had an average particle size of 0.52 μm.

Then, 500 g of deionized water, 715 g of vinyl chloride monomer and 48 g of vinyl acetate monomer and 8.6 g of 5% aqueous sodium lauryl sulfate in a 2.5 liter autoclave, and the vinyl chloride resin seed obtained as described above. 80 g of latex and 4 g of 0.1% aqueous solution copper sulfate were charged, and then the temperature of this reaction mixture was raised to 35 ° C. to proceed with seed fine suspension polymerization. From the start of the polymerization to the end of the polymerization, 120 g of 5% aqueous sodium lauryl sulfate and 0.05% aqueous ascorbic acid were continuously added, and the polymerization reaction was stopped when the pressure of the autoclave decreased to 0.22 MPa.

The polymerization time at that time was 756 minutes.

Then, the unreacted monomer was recovered to obtain a paste PVC latex. The obtained paste PVC latex was spray-dried with a spray dryer at a hot air inlet temperature of 160 ° C. and an outlet temperature of 55 ° C. to obtain a paste PVC which is a vinyl chloride-vinyl acetate copolymer.

A paste PVC sol was prepared using the obtained paste PVC, and its physical properties were evaluated. The results are shown in Table 2.

Comparative Example 1
990 g of deionized water, 700 g of vinyl chloride monomer, 63 g of lauryl peroxide, and 100 g of a 10 wt% sodium dodecylbenzene sulfonate aqueous solution were charged in a 2.5 L autoclave, and the polymer solution was circulated for 90 minutes using a homogenizer. After the homogenization treatment, the temperature was raised to 35 ° C. to proceed with the polymerization reaction. The polymerization reaction was stopped when the pressure of the autoclave dropped to 0.3 MPa, the unreacted vinyl chloride monomer was recovered, and an attempt was made to produce a vinyl chloride resin seed, but aggregation occurred and the vinyl chloride resin seed Could not be obtained. The results are shown in Table 3.

Comparative Example 2
990 g of deionized water, 700 g of vinyl chloride monomer, 9 g of t-butylperoxyneodecanoate, and 280 g of a 5 wt% sodium dodecylbenzene sulfonate aqueous solution were charged in a 2.5 L autoclave, and the polymerization solution was used as a homogenizer. After 90 minutes of circulation and homogenization treatment, the temperature was raised to 35 ° C. to proceed with polymerization. The polymerization reaction was stopped when the pressure of the autoclave dropped to 0.3 MPa, the unreacted vinyl chloride monomer was recovered, and an attempt was made to produce a vinyl chloride resin seed, but aggregation occurred and the vinyl chloride resin seed Could not be obtained. The results are shown in Table 3.

Comparative Example 3
1 m ³ stainless steel autoclave in deionized water 360 kg, vinyl monomers 300kg chloride were charged lauryl peroxide 5.7kg and 15 wt% aqueous solution of sodium dodecylbenzenesulfonate 30kg, 3 hours circulated by a homogenizer the polymerization solution, After the homogenization treatment, the temperature of the reaction system was raised to 45 ° C. to start the polymerization reaction. The polymerization reaction was stopped when the pressure of the polymerization system began to decrease, and the unreacted vinyl chloride monomer was recovered to obtain a latex containing a vinyl chloride resin containing a lauryl peroxide as a polymerization initiator. The obtained latex had a solid content of 35% by weight and an average particle size of 0.55 μm, and a latex containing 2% by weight of lauroyl peroxide with a vinyl chloride resin as a trunk was obtained. The results are shown in Table 3.

Then, in a 2.5 liter autoclave, 500 g of deionized water, 715 g of vinyl chloride monomer and 48 g of vinyl acetate monomer, 8.6 g of 5% aqueous sodium lauryl sulfate, and 80 g of latex obtained as described above. 4 g of 0.1% aqueous solution of copper sulfate was charged, and then the temperature of this reaction mixture was raised to 35 ° C. to proceed with seed microsuspension polymerization. From the start of the polymerization to the end of the polymerization, 120 g of 5% aqueous sodium lauryl sulfate and 0.05% aqueous ascorbic acid were continuously added, and the polymerization reaction was stopped when the pressure of the autoclave decreased to 0.22 MPa.

The polymerization time at that time was 1213 minutes.

Then, the unreacted monomer was recovered to obtain a paste PVC latex. The obtained paste PVC latex was spray-dried with a spray dryer at a hot air inlet temperature of 160 ° C. and an outlet temperature of 55 ° C. to obtain a paste PVC which is a vinyl chloride-vinyl acetate copolymer.

A paste PVC sol was prepared using the obtained paste PVC, and its physical properties were evaluated. The results are shown in Table 4.

Comparative Example 4
1 m ³ into the autoclave deionized water 360 kg, vinyl monomers 300kg chloride, lauryl peroxide 10kg and 15 wt% aqueous solution of sodium dodecylbenzenesulfonate 30kg, were charged dodecyl mercaptan 1.5 kg, 2 hours circulated by a homogenizer The polymer solution After the homogenization treatment, the temperature was raised to 45 ° C. to start the polymerization reaction. The polymerization reaction was stopped when the pressure of the polymerization system began to decrease, and the unreacted vinyl chloride monomer was recovered to obtain a latex containing a vinyl chloride resin containing a lauryl peroxide as a polymerization initiator. The results are shown in Table 3.

Then, in a 2.5 liter autoclave, 500 g of deionized water, 715 g of vinyl chloride monomer and 48 g of vinyl acetate monomer, 8.6 g of 5% aqueous sodium lauryl sulfate, and 80 g of latex obtained as described above. 4 g of 0.1% aqueous solution of copper sulfate was charged, and then the temperature of this reaction mixture was raised to 35 ° C. to proceed with seed microsuspension polymerization. From the start of the polymerization to the end of the polymerization, 120 g of 5% aqueous sodium lauryl sulfate and 0.05% aqueous ascorbic acid were continuously added, and the polymerization reaction was stopped when the pressure of the autoclave decreased to 0.22 MPa.

The polymerization time at that time was 950 minutes.

Then, the unreacted monomer was recovered to obtain a paste PVC latex. The obtained paste PVC latex was spray-dried with a spray dryer at a hot air inlet temperature of 160 ° C. and an outlet temperature of 55 ° C. to obtain a paste PVC which is a vinyl chloride-vinyl acetate copolymer.

A paste PVC sol was prepared using the obtained paste PVC, and its physical properties were evaluated. The results are shown in Table 4.

The vinyl chloride-based resin seed obtained by the present invention can significantly shorten the polymerization time when producing a paste vinyl chloride, and the obtained paste vinyl chloride is a paste vinyl chloride sol prepared by dispersing it in a plasticizer. It has become possible to provide a coating material, particularly an automobile underbody coating material and an automobile sealant material, which has little change in viscosity with time and has excellent mechanical strength during low-temperature processing, and its industrial use. The possibility is extremely high.

Claims (6)

When a vinyl chloride monomer, an emulsifier, a polymerization initiator, and a chain transfer agent are added to an aqueous medium, mixed, homogenized, and then polymerized to produce a vinyl chloride resin seed containing the polymerization initiator. to, vinyl chloride resin, characterized in that using a polymerization initiator 4-10 parts by weight based on the vinyl chloride monomer 100 parts by weight, and further adding 0.5 to 5 parts by weight of an emulsifier after the completion of the polymerization reaction How to make seeds . The method for producing a vinyl chloride resin seed according to claim 1, wherein the polymerization initiator is an oil-soluble polymerization initiator. The method for producing a vinyl chloride resin seed according to claim 1 or 2, wherein the emulsifier is an alkylbenzene sulfonate . The invention according to any one of claims 1 to 3, wherein 50 to 200 parts by weight of the aqueous medium and 0.5 to 5 parts by weight of the chain transfer agent are used with respect to 100 parts by weight of the vinyl chloride monomer. Method for producing vinyl chloride resin seeds. A method for producing a vinyl chloride resin for paste processing, which comprises performing seed polymerization of a vinyl chloride monomer in the presence of a vinyl chloride resin seed by the production method according to any one of claims 1 to 4. The method for producing a vinyl chloride resin for paste processing according to claim 5, wherein the seed polymerization is seed fine suspension polymerization.