JPH06145208A - Dispersion auxiliary for suspension polymerization of vinylic compound - Google Patents

Abstract

PURPOSE:To provide a dispersion auxiliary giving uniform vinylic polymer particles having an excellent porosity on the suspension polymerization of the vinylic compound; a method for producing the vinylic polymer excellent in various physical properties; and a method for producing the vinylic polymer especially highly improved in thermal stability. CONSTITUTION:The dispersion auxiliary comprises a water-insoluble polymer composed from the units of a radically polymerizable monomer and having a SH group at its one end. The method for producing the vinylic polymer comprises suspension-polymerizing a vinylic compound in the presence of the dispersion auxiliary in an aqueous medium heated to >=40 deg.C. And the method for producing the vinylic polymer comprises adding the water-insoluble polymer having the SH group at its one end at the time when the polymerization degree is <=60%, and subsequently suspension-polymerizing the vinylic compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersion aid for suspension polymerization of vinyl compounds, and more specifically, to the vinyl polymer particles obtained by suspension polymerization of vinyl compounds such as vinyl chloride. Auxiliary agent with excellent ability to efficiently produce a vinyl polymer having excellent quality using the dispersion auxiliary agent, and a method for efficiently producing a vinyl polymer having excellent thermal stability It is about.

[0002]

2. Description of the Related Art Conventionally, when a vinyl-based polymer such as a vinyl chloride-based resin is industrially produced, a vinyl chloride monomer or the like in the presence of a dispersion stabilizer is dispersed in an aqueous medium. A suspension polymerization method in which a vinyl compound is dispersed and polymerization is performed using an oil-soluble catalyst is widely practiced. Generally, factors that control the quality of vinyl polymers include polymerization rate, water-monomer ratio, polymerization temperature, type and amount of catalyst, type of polymerization tank, stirring speed or type of dispersion stabilizer. In particular, it is known that the influence of the type of dispersion stabilizer is extremely large.

The performance required of a dispersion stabilizer for suspension polymerization of vinyl compounds is (i) that it has the function of making the particle size distribution of the resulting vinyl polymer particles as sharp as possible, and (ii) plasticity. In order to increase the absorption rate of the agent to facilitate processability, to facilitate removal of vinyl chloride monomer etc. remaining in the polymer particles, and to prevent the formation of fish eyes etc. in the molded product. Therefore, it has a function of making each polymer particle as uniform and porous as possible, (iii) having a function of forming polymer particles having a high packing specific gravity, and (iv) having no scale attached to a polymerization tank or the like. , (V) the obtained polymer particles have high thermal stability, and (vi) the obtained polymer particles have excellent gelling properties.

Conventionally, as a dispersion stabilizer for suspension polymerization of vinyl compounds, cellulose derivatives such as methyl cellulose and carboxymethyl cellulose, partially saponified polyvinyl alcohol and the like have been used singly or in combination. However, these dispersion stabilizers
There are drawbacks such as low ability to make the vinyl polymer particles porous, slow plasticizer absorption rate, or difficulty in removing residual vinyl monomer. For the purpose of improving these drawbacks, oil-soluble polyvinyl alcohol having a saponification degree of 60 mol% or less (hereinafter, polyvinyl alcohol is referred to as PVA
(Hereinafter sometimes abbreviated)), polymethylmethacrylate, polyethylene and the like are used with a conventionally known dispersion stabilizer. However, in this case, although a porous vinyl polymer is obtained,
There is a fatal drawback that the filling specific gravity is likely to decrease.
In addition, the research group of the present inventors is based on Japanese Patent Laid-Open No. 64-755.
No. 05, a block copolymer (A) of PVA and a lipophilic polymer, and a PVA (B) having a saponification degree of 70 to 95 mol% and a polymerization degree of 300 to 3000 (A) / (B). Is 30/70 to 90/10 by weight.
When the dispersion stabilizer is used, the reproducibility is almost the same and has a sharp particle size distribution, each particle is porous and excellent in uniformity, and the filling specific gravity is large.
It was found that the performance of (iii) can be satisfied. But,
The lipophilic polymer that constitutes this dispersion stabilizer has 4 carbon atoms.
The following lipophilic polymers having an alkyl group were not satisfactory in terms of (iv) adhesion of scale to polymerization tank and (v) thermal stability of polymer particles.

Further, the research group of the present inventors, in JP-A-3-290402, discloses a block copolymer (A) of PVA and a lipophilic polymer having an alkyl group having 5 or more carbon atoms, and a saponification degree. 65-95 mol%,
Made of PVA (B) with a degree of polymerization of 300 to 3000,
It has been found that the use of a dispersion stabilizer in which (A) / (B) is in a weight ratio of 10/90 to 90/10 can solve the above-mentioned problems (iv) and (v). vi)
The problem remains that the resulting polymer particles have poor gelling properties. Furthermore, the research group of the inventors of the present invention, in PCT / JP91 / 00420, provides a dispersion aid having an amino group, an ammonium group, a sulfonic acid group, a carboxyl group or a salt thereof at a terminal and having a saponification degree of 60 mol% or less. Although the suspension polymerization method used has been disclosed, the polymer particles obtained in this case also have a drawback that the gelling property is poor.

On the other hand, suspension polymerization of vinyl compounds such as vinyl chloride is usually carried out in a batch system, and an aqueous medium, a dispersant (suspension agent), a polymerization initiator and a vinyl compound are charged in a polymerization vessel. A general method is to add the required additives and then raise the temperature to carry out the polymerization reaction. However, in order to improve productivity, it is required to shorten the time required for one batch of polymerization, and for that purpose, shortening of the charging time, reduction of reaction time, and the like as well as shortening of the temperature raising time are also performed. There is a need. Particularly in a large-sized polymerization vessel or a polymerization vessel with a condenser, the heating capacity of the jacket or the like is relatively small compared to the internal volume, so it was necessary to develop a more effective temperature raising method.
For this reason, in suspension polymerization of vinyl compounds such as vinyl chloride, a method has been used in which a preheated aqueous medium is charged to eliminate the heating time and improve the productivity. However, when such a method is used, the obtained vinyl-based polymer such as vinyl chloride-based resin has many fish eyes, and has a fatal defect that the plasticizer absorbability and the demomerization property are poor.

Generally, vinyl polymers such as vinyl chloride resin are excellent in physical properties such as mechanical strength, weather resistance, chemical resistance and self-extinguishing property, and can be used for pipes, plates, films, sheets or containers. However, it has a drawback in that it has a low softening temperature and therefore is inferior in heat distortion resistance. For example, a hard vinyl chloride resin is generally 7
Since thermal deformation occurs at 0 to 80 ° C, there is a problem that it cannot be used at temperatures higher than that.

Conventionally, various methods have been proposed to improve the heat distortion resistance, for example, vinyl chloride-N.
-Allylmaleimide copolymers and the like have been proposed. Although this copolymer has improved heat resistance and excellent fluidity, it has the drawback of being poor in thermal stability and being easily dehydrochlorinated during heat molding. In addition, vinyl chloride resin after suspension polymerization,
As a method of blending a so-called heat stabilizer, for example,
Although it has been proposed to add an organic tin stabilizer, a lead stabilizer, a violite compound, etc., the thermal stability is still insufficient and it is not practical.

Further, in Japanese Patent Laid-Open No. 2-276847, a vinyl chloride resin, a methyl methacrylate component, N
Selected from the group consisting of alkyl acrylates, methacrylic acid alkyl esters, aromatic vinyl compounds and vinyl cyanide compounds in the presence of a copolymer comprising a substituted maleimide component and an aromatic vinyl component or an elastomer containing a conjugated diene component. A method of blending a copolymer obtained by graft-polymerizing one or more kinds of monomers has been proposed. According to this method, the resin obtained is improved in impact resistance but is still insufficient in thermal stability and is not suitable for practical use.

On the other hand, in suspension polymerization of vinyl chloride monomer, polymethacrylic acid ester such as polymethylmethacrylate (PMMA) or polyacrylic acid ester, polyvinyl ester such as polyvinyl acetate (PVAc), polyester such as polystyrene, etc. Suspension polymerization methods in which an aromatic vinyl polymer is added at a ratio of 1% by weight or less with respect to a vinyl chloride monomer have been conventionally known. However, these methods are used for processing the resulting vinyl chloride resin. Although effective in improving the properties, it had no effect in improving the thermal stability. In addition, there is a fatal drawback that when these polymers are added in an amount of 5% by weight or more based on the vinyl chloride monomer during suspension polymerization, the polymerization stability is adversely affected. Further, as a dispersion aid or a dispersion stabilizer for suspension polymerization having an effect of improving thermal stability, for example, JP-A-3-290402,
There are those disclosed in JP-A-3-290403, JP-A-3-290404 and JP-A-4-93301, but none of them are sufficiently satisfactory.

[0011]

Under the above circumstances, the present invention provides a dispersion aid which simultaneously satisfies the required characteristics (i) to (vi), and a quality improvement using the dispersion aid. The object of the present invention is to provide a method for efficiently producing an excellent vinyl polymer and a method for efficiently producing a vinyl polymer having excellent thermal stability.

[0012]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have surprisingly found that it is composed of radically polymerizable monomer units and has an SH group at one end. It was found that the dispersion aid composed of a water-insoluble polymer having the above-mentioned properties satisfies all the required performances (i) to (vi). Further, when suspension-polymerizing a vinyl-based compound such as vinyl chloride, by introducing the above dispersion aid together with the heated aqueous medium into the polymerization reaction system, the polymerization time for one batch can be significantly shortened. It was found that a high-quality vinyl polymer having less fish eyes and having good plasticizer absorbability and demomerization property can be obtained. further,
During suspension polymerization of vinyl compounds such as vinyl chloride,
Suspension polymerization stability and resin processing by adding a water-insoluble polymer having an SH group at one end to the polymerization system at a specific ratio to the vinyl compound at a relatively low polymerization rate. It has been found that its thermal stability can be significantly improved without compromising its properties. The present invention has been made based on such findings.

That is, the present invention is composed of a radically polymerizable monomer unit and has a general formula Z-SH (I) having an SH group at one end (wherein Z is radically polymerizable). The present invention provides a dispersion aid for suspension polymerization of a vinyl compound consisting of a water-insoluble polymer represented by the formula (1) or a polymer component consisting of two or more kinds of monomer units. In the present invention, the vinyl compound is added at 40 ° C in the presence of a polymerization initiator and a dispersion stabilizer.
The present invention provides a method for producing a vinyl-based polymer, which comprises using the above-mentioned dispersion aid in carrying out suspension polymerization by adding the heated aqueous medium. Further, according to the present invention, when a vinyl compound is suspension-polymerized in an aqueous medium in the presence of a polymerization initiator and a dispersion stabilizer, the polymerization rate is 6%.
At 0% or less, 5 to 100 parts by weight of a water-insoluble polymer having an SH group at one end represented by the above general formula (I) was added to 100 parts by weight of the vinyl compound in the polymerization system. The present invention provides a method for producing a vinyl polymer, characterized in that

The dispersion aid of the present invention is a polymer represented by the general formula Z-SH ... (I) and having an SH group at one end and must be water-insoluble. The Z component is composed of one or more kinds of radically polymerizable monomer units and may have a graft structure. The Z component is composed of one or more kinds of radically polymerizable monomer units (co).
Although it is a polymer, various radical polymerizable monomers can be used. Specific preferred examples include (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylic acid amide, vinyl ester, vinyl ether and α-olefin, and derivatives thereof. Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, cyclohexyl (meth) acrylate,
2-Ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, (meth)
Examples thereof include stearyl acrylate and behenyl (meth) acrylate. Examples of vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatic acid, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, palmitic acid. Examples include vinyl, vinyl stearate, vinyl oleate, and the like. When the vinyl ester is saponified and used, the saponification degree is preferably adjusted to 50 mol% or less. Examples of vinyl ethers include methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether. Furthermore, examples of the α-olefin and its derivative include ethylene, propylene, isoprene, styrene, acrylonitrile, and vinyl chloride.

The (co) polymer used as the dispersion aid of the present invention preferably has an average degree of polymerization (Pn) of 5000 or less. This (co) polymer is not particularly limited in its production method as long as it is represented by the general formula Z-SH (Z has the same meaning as described above), and it is produced by various methods. Can be applied. However, among various methods, when radically polymerizing a monomer, thiolcarboxylic acid, 2-acetylthioethylthiol, 1
Polymerization is performed in the presence of a compound containing a thioester and a thiol group in the molecule such as 0-acetylthiodecanethiol, and the obtained polymer is treated with an alkali such as sodium hydroxide or ammonia to give a thiol at one end. The method of obtaining a polymer having a group is most preferable as a method of obtaining the (co) polymer used as the dispersion aid of the present invention simply and efficiently.

In the present invention, as a method for producing a vinyl polymer, firstly, when a vinyl compound is suspension-polymerized in the presence of a polymerization initiator and a dispersion stabilizer, an aqueous solution heated in a polymerization reaction system is used. By introducing the above-mentioned dispersion aid together with the medium, the polymerization time for one batch can be significantly shortened, and at the same time, a high quality vinyl polymer having few fish eyes and good plasticizer absorbability and demomerization property can be obtained. Secondly, when the vinyl compound is suspension-polymerized in the presence of a polymerization initiator and a dispersion stabilizer, the water represented by the general formula Z-SH is added at a time when the polymerization rate is relatively low. Provided is a method for producing a vinyl polymer having remarkably improved thermal stability by adding an insoluble polymer to a polymerization system. Next, a method for producing the first vinyl polymer will be described. In this method for producing a vinyl polymer, the amount of the dispersion aid used is not particularly limited, but the vinyl compound 1
The amount is preferably 5 parts by weight or less, more preferably 1 part by weight or less with respect to 00 parts by weight. In carrying out suspension polymerization of the vinyl compound using the dispersion aid, the production method is not particularly limited, and a conventionally known method can be used. The dispersion stabilizer to be used may be one normally used in suspension polymerization of vinyl compounds such as vinyl chloride in an aqueous medium, and examples thereof include methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropyl. Water-soluble cellulose ethers such as methyl cellulose, partially saponified polyvinyl alcohol (saponification degree 60 to 95 mol%, average polymerization degree 500 or more) and modified products of this ionic group or nonion group, low saponification degree PVA (saponification degree less than 60 mol%, average Polymerization degree of 3,000 or less) and its ionic or nonionic modified products, water-soluble polymers such as gelatin, sorbitan monolaurate, sorbitan trioleate, glycerin tristearate, ethylene oxide propylene oxide block copolymers, etc. Soluble emulsifier, polyoxyethylene sorbitan monolaurate, polyoxyethylene glycerin oleate, and water-soluble emulsifying agents such as sodium laurate and the like, which are added in one or two or more thereof. The amount added is not particularly limited, but is preferably 0.03 to 0.15 part by weight per 100 parts by weight of a vinyl compound such as vinyl chloride.

Various other additives can be added as required. As various additives that can be used, for example, acetaldehyde, butyraldehyde, trichloroethylene, perchlorethylene, mercaptans and other polymerization degree regulators, phenol compounds, sulfur compounds, N-
There are polymerization inhibitors such as oxide compounds. Also, p
It is also optional to add an H-adjusting agent, a scale inhibitor, a crosslinking agent, etc., and a plurality of the above-mentioned additives may be used in combination. It is also effective to attach a condenser such as a condenser to the polymerization device.

On the other hand, the polymerization initiator may also be the one conventionally used for the polymerization of vinyl compounds such as vinyl chloride,
This includes, for example, percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate, t-butyl peroxyneodecanate, α-cumylperoxyneodecanate. , T-
Perester compounds such as butylperoxyneodecanate, acetylcyclohexylsulfonyl peroxide, peroxides such as 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, 2,2′-azobisisobutyronitrile , Azobis-2,4-dimethylvaleronitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), and other azo compounds, and further, potassium persulfate, ammonium persulfate, hydrogen peroxide, and the like. It can also be used in combination. The amount of addition is preferably in the range of 0.02 to 0.3 parts by weight per 100 parts by weight of vinyl compound such as vinyl chloride.

There are various vinyl compounds which can be suspension-polymerized by using the dispersion aid of the present invention. Specifically, vinyl chloride alone and a monomer mainly containing vinyl chloride are available. As a comonomer that includes a mixture (50% by weight or more of vinyl chloride) and is copolymerized with this vinyl chloride, vinyl acetate, vinyl ester such as vinyl propionate, methyl (meth) acrylate, ethyl (meth) acrylate, etc. (Meth) acrylic acid ester of ethylene,
Olefin such as propylene, maleic anhydride, acrylonitrile, itaconic acid, styrene, vinylidene chloride,
Examples include vinyl ether and other monomers copolymerizable with vinyl chloride. Further, the dispersion aid of the present invention can be used even in homopolymerization or copolymerization of the above vinyl compound containing no vinyl chloride. In carrying out suspension polymerization using the dispersion aid of the present invention, the charging ratio of each component, the polymerization temperature, etc. may be determined according to the conditions conventionally used in suspension polymerization of vinyl compounds such as vinyl chloride. Well, there is nothing to limit.

By the way, the above-mentioned method for producing a vinyl polymer of the present invention uses an aqueous medium heated to 40 ° C. or higher at the time of charging, and the above-mentioned Z-SH type of the present invention is used as a dispersion aid. A dispersion aid composed of a (co) polymer is used. The heating aqueous medium used here has a temperature of 40 ° C. or higher, and the upper limit thereof is not particularly limited, and hot water of 95 ° C. or higher may be used. The medium constituting the heated aqueous medium is not limited to pure water, and may be an aqueous solution containing various additive components, or an aqueous medium containing other organic solvent, or any medium that does not interfere with suspension polymerization of vinyl compounds. For example, various aqueous media can be mentioned. Also,
The amount of the heating aqueous medium to be fed when charging the polymerization reaction system may be appropriately determined according to various situations as long as the polymerization reaction system can be sufficiently heated. The type of vinyl compound to be polymerized, the type of polymerization initiator used, and the type of dispersion stabilizer are not particularly limited and may be appropriately selected from those already described above. In addition, vinyl compounds, polymerization initiators,
The order and ratio of the dispersion stabilizer, the heating aqueous medium and the other additives are not limited. The vinyl-based polymer thus obtained has a sharp particle size distribution, few fish eyes, good plasticizer absorbability and demomerization properties, and a large packing specific gravity and thermal stability. And excellent gelling properties. Further, according to the above-mentioned polymerization method, the scale does not adhere to the polymerization tank or the like, and the polymerization time for one batch can be greatly shortened.

Next, the method for producing the second vinyl polymer will be described. In this method for producing a vinyl-based polymer, SH at one end represented by the above general formula Z-SH is used.
It is necessary to add a water-insoluble polymer having a group to the polymerization system when the polymerization rate (conversion rate) of the monomer is 60% or less. The addition time is preferably 30% or less, more preferably 10% or less, and particularly preferably at the time of initiation of polymerization or before initiation. If it is added after the conversion of the monomer exceeds 60%, the mixing with the vinyl compound becomes insufficient and the effect is not exhibited. The Z-SH type polymer is added in an amount of 5 to 100 parts by weight, preferably 20 to 80 parts by weight, and more preferably 40 to 70 parts by weight, based on 100 parts by weight of the vinyl compound. In this method for producing a vinyl-based polymer, the dispersion stabilizer used in suspension polymerization, various additives used as necessary, and the polymerization initiator are those exemplified in the description of the first production method. The same can be mentioned. Further, as the vinyl compound, the same monomers as those exemplified in the explanation of the first method can be used. In addition, the water-insoluble polymer represented by the general formula Z-SH is added to the vinyl-based monomer 10 at the time when the polymerization rate of the monomer is 60% or less.
If 5 to 100 parts by weight is added to 0 parts by weight, the charging ratio of each component, the charging sequence, the polymerization temperature, etc. are in accordance with the conditions conventionally used in suspension polymerization of vinyl compounds such as vinyl chloride. It may be set, and there is no particular limitation. The charging temperature of water used for polymerization is also not particularly limited, and so-called hot charging method in which warm water of 40 to 95 ° C is charged can be used. According to such a method, a vinyl polymer having remarkably improved thermal stability can be obtained without impairing suspension polymerization stability and resin processing characteristics.

If necessary, various rubber components may be added to the vinyl polymer such as vinyl chloride resin obtained by the method of the present invention. Examples of the rubber component that can be added here include polybutadiene, styrene-butadiene block polymer, nitrile rubber, maleated rubber, polyisoprene rubber, butadiene-acrylonitrile rubber, ethylene-propylene-diene terpolymer, butadiene-styrene-butadiene. Examples thereof include terpolymers and butadiene-isoprene-butadiene terpolymers. Similarly, metal soaps such as calcium stearate, zinc stearate, barium stearate, cadmium stearate and lead stearate, which have been conventionally used as stabilizers for vinyl chloride resins, dibasic sulfates, dibasic stearin. Lead acid,
Inorganic stabilizers such as calcium hydroxide and calcium silicate, as well as lubricants, pigments, fillers, impact modifiers, processing aids and ultraviolet absorbers may be added later.

[0023]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, "%" and "part" are "% by weight" unless otherwise specified.
And "parts by weight". Production Example 1 [Production of polymethylmethacrylate having a mercapto group at the end] Methylmethacrylate (hereinafter abbreviated as MMA)
After 290 parts and 4.6 parts of thioacetic acid were placed in a reaction vessel and the inside was thoroughly replaced with nitrogen, the outer temperature was raised to 85 ° C., and 2.
MMA containing 0.3 parts of 2'-azobisisobutyronitrile
Polymerization was carried out by adding 10 parts. The polymerization rate after 1.5 hours is 7
It was 8.8%. After the polymerization, the content was diluted with acetone and poured into n-hexane to precipitate and precipitate the polymer, and the precipitation and precipitation were repeated three times with acetone and water.
A was removed. Next, 200 g of this polymer was added to acetone 3
Dissolve in a mixed solvent of 20g and 80g of methanol,
Add 12 g of 0% NaOH in methanol and add 40 ° C.
And reacted for 2.5 hours. Then, the mixture was poured into 5 liters of water containing 50 ml of 1N H ₂ SO ₄ , and the precipitated polymer was separated by filtration, washed thoroughly with water and dried to give polymethylmethacrylate (having a mercapto group at one end ( Below P
(Sometimes abbreviated as MMA). When the intrinsic viscosity [η] of this PMMA was measured at 30 ° C. in acetone, it was [η] = 0.06 (dl / g), and the mercapto group content was the result of titration with iodine in an acetone-water system. 9.9
It was 9 × 10 ⁻⁵ equivalent / g.

Production Example 2 [Production of polystyrene having a mercapto group at the end] 9.8 g of a toluene solution of thioacetic acid having a concentration of 10% was added to 1200 g of styrene, and 2,2'-azobisisobutyrate was used as a polymerization initiator. 0.35 g of ronitrile was added, and the temperature was 70 ° C.
Polymerized in. The polymer obtained at a conversion of 25% was reprecipitated and purified in methanol, and then unreacted styrene monomer was removed with methanol Soxhlet. Dissolve 30 g of the obtained polymer in 90 g of toluene,
0.16 g of 10% concentration NaOH methanol solution was added at 0 ° C. and reacted for 2 hours. After being neutralized with acetic acid, it was thoroughly washed with water and dried to obtain polystyrene having a mercapto group at one end (hereinafter abbreviated as PSt).

Example 1A PVA with a degree of saponification of 85 mol% and an average degree of polymerization of 2500
Suspension polymerization of vinyl chloride was carried out using 0.06 part of a dispersant (dispersion stabilizer) consisting of and a dispersion aid of 0.03 part consisting of the PMMA-SH polymer obtained according to the above-mentioned production example. The procedure was as follows. The amount of dispersant used, the amount of dispersion aid used, and the amount of Z-SH type polymer used in the following Examples and Comparative Examples are based on 100 parts by weight of vinyl chloride.
That is, 40 parts of deionized water, 0.06 part of the dispersant, 0.03 part of the dispersant and 50 parts of diisopropyl peroxydicarbonate were placed in a glass-lined autoclave.
% Toluene solution 0.009 parts was charged, and the inside of the autoclave was degassed to 50 mmHg to remove oxygen.
30 parts of vinyl chloride was charged and the temperature was raised to 57 ° C. with stirring to carry out polymerization. At the start of polymerization, the pressure inside the autoclave is
It was 8.0 kg / cm ² G, but it was 5.
Since it reached 0 kg / cm ² G, the polymerization was stopped at this point, unreacted vinyl chloride monomer was purged, and the contents were taken out and dehydrated and dried. Table 1 shows the types and amounts of the dispersants (dispersion stabilizers) and dispersion aids used in the suspension polymerization, and Table 2 shows the performance of the obtained vinyl chloride resin. The vinyl chloride resin has a polymerization yield of 85% and an average degree of polymerization of 1100.
Met.

Examples 2A-20A and Comparative Examples 1A-7
A Suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1A except that the types and amounts of the dispersant (dispersion stabilizer) and the dispersion aid were changed as shown in Table 1. The performance of the obtained vinyl chloride resin is shown in Table 2.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Table 4]

MMA: methyl methacrylate EA: ethyl acrylate 2EHA: 2-ethylhexyl acrylate MBA: butyl methacrylate MA: methacrylic acid VAc: vinyl acetate Et: ethylene St: styrene PVi: vinyl pivalate BA: acrylic acid n- Butyl IA: Itaconic acid

[0032]

[Table 5]

[0033]

[Table 6]

[0034]

[Table 7]

[0035]

[Table 8]

[0036]

[Table 9]

[0037]

[Table 10]

(1) Particle size distribution The particle size distribution was measured by dry sieve analysis using a wire mesh based on Tyler mesh. (2) Fisheye measurement method 100 parts vinyl chloride resin obtained by polymerization, 1 part tribasic lead sulfate, 1.5 parts lead stearate, 0.2 parts titanium dioxide.
Part, carbon black 0.1 part, dioctyl phthalate 5
25 g of the composition obtained by mixing 0 parts was kneaded with a roll at 145 ° C. for 5 minutes and separated as a 0.2 mm thick sheet. The number of transparent particles in 100 cm ² of this sheet was shown. (3) Absorption of plasticizer In a planetary mixer connected to a plastograph,
Add 400 g of vinyl chloride resin powder obtained by polymerization, preheat (4 minutes) while stirring at 60 rpm, and heat at 80 ° C.
After that, 200 g of dioctyl phthalate was added thereto, and the time until the time when the torque decreased due to the addition was defined as the plasticizer absorbability (minutes). (4) Residual vinyl chloride monomer The vinyl chloride monomer content in the vinyl chloride resin was quantified by headspace gas chromatography. (5) Thermal stability (colorability) test: Vinyl chloride resin 100
Part, 2.5 parts of dibutyltin maleate and 80 parts of dioctyl phthalate as a plasticizer were mixed and kneaded on a roll at 160 ° C. for 10 minutes, a 1 mm thick sheet was taken out, and the degree of coloring of the sheet was visually observed. . (6) Gelation property 65 g of the same composition as in the fish eye measurement
In a plastograph (type 50 kneader) and the temperature was 19
The time (minutes) from when stirring was started under the condition of 0 ° C. and 60 rpm to the maximum torque was shown.

Examples 1B to 20B and Comparative Examples 1B to 7B In the above Examples 1A to 20A or Comparative Examples 1A to 7A, 45 parts of deionized water heated to 63 ° C. was charged, and the internal temperature after charging was 57 ° C. Suspension polymerization of vinyl chloride was carried out under the same conditions except the above. The performance of the obtained vinyl chloride resin is shown in Table 3. The same example numbers A and B correspond to each other, and the same comparative example numbers A and B correspond to each other.

[0040]

[Table 11]

[0041]

[Table 12]

[0042]

[Table 13]

[0043]

[Table 14]

Examples 21 to 31 Suspension polymerization of vinyl chloride was carried out by the following method. That is, deionized water 50 in a glass lined autoclave.
Parts, a dispersant, and 0.009 parts of a 50% toluene solution of diisopropyl peroxydicarbonate were charged, the interior of the autoclave was degassed to 50 mmHg to remove oxygen, and then 30 parts of vinyl chloride were charged, and the mixture was stirred under agitation of 57 parts. ℃
The temperature was raised to 0 to carry out polymerization. At this time, the Z-SH type polymer was added to the polymerization system before or after the initiation of the polymerization. At the start of the polymerization, the pressure in the autoclave was 8.0 kg / cm ² G, but it reached 5.0 kg / cm ² G 6 hours after the start of the polymerization, so the polymerization was stopped at this point and the unreacted vinyl chloride monomer Was purged, the contents were taken out and dehydrated and dried. Table 4 shows the types and amounts of the dispersant (dispersion stabilizer) and Z-SH type polymer used in the suspension polymerization, the time of addition of the Z-SH type polymer, and the performance of the vinyl chloride resin in Table 5. Shown in.

[0045]

[Table 15]

[0046]

[Table 16]

EVA: Ethylene-vinyl acetate The symbols of other monomer components are the same as in the footnotes in Table 1.

[0048]

[Table 17]

[0049]

[Table 18]

(1) Average particle diameter Using a steel rope based on Tyler mesh, it was measured by dry node analysis. (2) Thermal stability The vinyl chloride resin obtained by suspension polymerization was dried at 65 ° C for 8 hours, and then the resin particles were heated in a hot block bath at 185 ° C to visually check the degree of coloring as follows. It evaluated according to the criteria. ◎: No coloration ○: Slightly coloration △: Colored pink ×: Colored red to brown

Comparative Examples 8 to 10 Instead of the Z-SH type polymer, a polymer having no SH group was used as shown in Table 6, or no polymer was used, and Examples 21 to 31 were used. Suspension polymerization of vinyl chloride was carried out in the same manner as in. Table 6 shows the type and amount of the dispersant (dispersion stabilizer) and the added polymer used in the suspension polymerization, and the addition timing of the polymer, and Table 7 shows the performance of the vinyl chloride resin. In addition,
The method of measuring the average particle size and the thermal stability is the same as the footnote in Table 5.

[0052]

[Table 19]

[0053]

[Table 20]

[0054]

INDUSTRIAL APPLICABILITY The dispersion aid of the present invention has a very high ability to make the formed vinyl polymer particles porous as compared with conventional dispersion aids, has a high plasticizer absorption rate, and remains. It shows excellent performance such as giving a vinyl polymer that can easily remove unreacted vinyl monomer. Further, the resulting vinyl-based polymer particles are excellent in various points such as a large particle size, a sharp distribution, little scattering during handling, and good biteability into a molding machine. is there. Further, according to the method for producing a vinyl polymer of the present invention using the above-mentioned dispersion aid, the polymerization time for one batch can be significantly shortened, and moreover, various types of grades have few fish eyes and a plasticizer. It is possible to obtain a high-quality vinyl polymer having good absorption and demomerization properties. Furthermore, by adding a relatively large amount of a polymer having an SH group at one end to the polymerization system when the polymerization rate is relatively low, it is possible to produce a vinyl polymer having remarkably excellent thermal stability.

Claims (3)

[Claims] 1. A general formula Z-SH comprising a radical-polymerizable monomer unit and having an SH group at one end, wherein Z is one or more radical-polymerizable monomer units. A dispersion aid for suspension polymerization of a vinyl compound consisting of a water-insoluble polymer represented by the formula (1). 2. In the presence of a polymerization initiator and a dispersion stabilizer,
2. The method for producing a vinyl polymer, wherein the dispersion aid according to claim 1 is used in suspension polymerization by adding an aqueous medium of a vinyl compound heated to 40 ° C. or higher. 3. In the presence of a polymerization initiator and a dispersion stabilizer,
In suspension-polymerizing a vinyl compound in an aqueous medium,
When the polymerization rate is 60% or less, the vinyl compound 100
Based on parts by weight, a general formula Z-SH, which is composed of radically polymerizable monomer units and has an SH group at one terminal, wherein Z is one or more radically polymerizable monomer units. The method for producing a vinyl polymer is characterized in that 5 to 100 parts by weight of a water-insoluble polymer represented by the formula (1) is added to the polymerization system.