JP3240196B2 - Method for producing vinyl polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to suspension polymerization of vinyl compounds such as vinyl chloride and the like, and uses a dispersing agent having excellent ability to make the obtained vinyl polymer particles uniform and porous. And a method for efficiently producing a vinyl polymer having excellent thermal stability.

[0002]

2. Description of the Related Art Conventionally, when a vinyl polymer such as a vinyl chloride resin is industrially produced, a vinyl polymer such as a vinyl chloride monomer is prepared in an aqueous medium in the presence of a dispersion stabilizer. A suspension polymerization method in which a vinyl compound is dispersed and polymerization is performed using an oil-soluble catalyst has been widely practiced. In general, factors governing the quality of a vinyl polymer include a polymerization rate, a water-monomer ratio, a polymerization temperature, a type and amount of a catalyst, a type of a polymerization tank, a stirring speed, and a type of a dispersion stabilizer. It is known that the effect of the type of dispersion stabilizer is extremely large.

The performance required of a dispersion stabilizer for suspension polymerization of a vinyl compound is as follows: (i) a function of sharpening the particle size distribution of the obtained vinyl polymer particles as much as possible; In order to increase processability by increasing the absorption rate of the agent, to facilitate removal of vinyl chloride monomer remaining in the polymer particles, and to prevent the formation of fish eyes and the like in molded articles Therefore, it has the function of making each polymer particle as uniform and porous as possible, (iii) has the function of forming polymer particles having a large filling specific gravity, and (iv) has no adhesion of scale to the polymerization tank. (V) that the obtained polymer particles have high thermal stability, and (vi) that the obtained polymer particles have excellent gelation properties.

Heretofore, as a dispersion stabilizer for suspension polymerization of a vinyl compound, a cellulose derivative such as methylcellulose, carboxymethylcellulose, or partially saponified polyvinyl alcohol has been used alone or in combination. However, these dispersion stabilizers
There are drawbacks in that the ability to make the vinyl polymer particles porous is low, the plasticizer absorption rate is low, or it is difficult to remove the residual vinyl monomer. In order to improve these disadvantages, an oil-soluble polyvinyl alcohol having a saponification degree of 60 mol% or less (hereinafter, polyvinyl alcohol is referred to as PVA).
), And polymethyl methacrylate, polyethylene, and the like, together with conventionally known dispersion stabilizers. However, in this case, although a porous vinyl polymer is obtained,
There was a fatal drawback that the filling specific gravity was easily reduced.
Further, the research group of the present inventors is disclosed in Japanese Unexamined Patent Publication No.
JP-A-05-2005, comprising a block copolymer (A) of PVA and a lipophilic polymer, and PVA (B) having a saponification degree of 70 to 95 mol% and a polymerization degree of 300 to 3000, wherein (A) / (B) Is 30/70 to 90/10 by weight
When the dispersion stabilizer is used, the above-mentioned (i) such that the dispersion stability is almost the same, the particle size distribution is almost the same, and each particle is porous and excellent in uniformity, and the packing specific gravity is large.
To (iii) were found to be satisfactory. But,
The lipophilic polymer constituting the dispersion stabilizer has 4 carbon atoms.
In the case of a lipophilic polymer having the following alkyl group, it was not satisfactory in terms of (iv) adhesion of scale to the polymerization tank and (v) thermal stability of the polymer particles.

Further, the research group of the present inventors disclosed in JP-A-3-290402 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%,
It consists of PVA (B) having a degree of polymerization of 300 to 3000,
It has been found that the use of a dispersion stabilizer having a weight ratio (A) / (B) of 10/90 to 90/10 can solve the above-mentioned problems (iv) and (v). vi)
There remains a problem that the obtained polymer particles have poor gelling properties. Still further, the research group of the present inventors has disclosed in PCT / JP91 / 00420 a dispersing aid having an amino group, an ammonium group, a sulfonic acid group, a carboxyl group or a salt thereof at a terminal having a degree of saponification of 60 mol% or less. The suspension polymerization method used is disclosed, but in this case also, there is a disadvantage that the gelling properties of the obtained polymer particles are 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 into a polymerization vessel. In general, a method of adding a necessary additive and then raising the temperature to cause a polymerization reaction is carried out. However, in order to improve the productivity, it is required to reduce the time required for one batch of polymerization, and for that purpose, the heating time is shortened along with the shortening of the charging time and the reaction time. There is a need. In particular, in the case of a large-sized polymerization vessel or a polymerization vessel with a condenser, the heating capacity of the jacket or the like is relatively small as compared with the internal volume, and therefore, it is necessary to develop a more effective heating method.
For this reason, in the suspension polymerization of a vinyl compound such as vinyl chloride, a method is used in which a heated aqueous medium is charged in advance to improve the productivity by eliminating the temperature rise time. However, when such a method is used, the obtained vinyl polymer such as a vinyl chloride resin has many fish eyes and has a fatal defect such as poor plasticizer absorption and demonomerization.

In general, vinyl polymers such as vinyl chloride resins are excellent in physical properties such as mechanical strength, weather resistance, chemical resistance and self-extinguishing properties, and are used for pipes, plates, films, sheets, containers and the like. However, it has a drawback that it has a low softening temperature and is therefore inferior in heat-resistant deformation. For example, rigid 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 a higher temperature.

Conventionally, various methods have been proposed for improving the heat-resistant deformation resistance. For example, vinyl chloride-N
-Allyl maleimide copolymers and the like have been proposed. This copolymer has improved heat resistance and excellent fluidity, but has poor thermal stability and has a drawback that it is 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,
It has been proposed to add an organotin-based stabilizer, a lead-based stabilizer or a biolite-based compound, but the thermal stability is still insufficient and is not practical.

Japanese Patent Application Laid-Open No. 2-276847 discloses that a vinyl methacrylate resin contains a methyl methacrylate component,
Selected from the group consisting of alkyl acrylates, alkyl methacrylates, 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 comprising a conjugated diene component. A method of blending a copolymer obtained by graft polymerization of one or more monomers has been proposed. According to this method, the obtained resin is improved in terms of impact resistance, but is still insufficient in thermal stability and is unsuitable for practical use.

On the other hand, in the suspension polymerization of a vinyl chloride monomer, a polymethacrylic acid ester such as polymethyl methacrylate (PMMA), a polyacrylic acid ester, a polyvinyl ester such as polyvinyl acetate (PVAc), and a polystyrene such as polystyrene. Suspension polymerization methods in which an aromatic vinyl polymer is added at a ratio of 1% by weight or less based on a vinyl chloride monomer have been conventionally known, but these methods involve processing of a vinyl chloride resin obtained. Although effective in improving the properties, there was no effect of improving the thermal stability. In addition, when these polymers are added in an amount of 5% by weight or more based on a vinyl chloride monomer during suspension polymerization, there is a fatal defect that polymerization stability is adversely affected. Further, as a dispersion aid or dispersion stabilizer for suspension polymerization having an effect of improving thermal stability, for example, JP-A-3-290402,
JP-A-3-290403, JP-A-3-290404, and JP-A-4-93301 have not been satisfactory.

[0011]

Under such circumstances, the present invention provides a vinyl-based polymer having excellent quality by using a dispersing agent which simultaneously satisfies the above-mentioned requirements (i) to (vi). An object of the present invention is to provide a method for efficiently producing a coalesced product and a method for efficiently producing a vinyl polymer having remarkably excellent thermal stability.

[0012]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, surprisingly, they are composed of monomer units capable of radical polymerization and have an SH group at one end. It meets all the performance requirements of the (i) ~ (vi) dispersing aid composed of a polymer of water-insoluble with, when the suspension polymerization of vinyl compounds such as vinyl chloride, is heated to the polymerization reaction system By introducing the above-mentioned dispersing aid together with the aqueous medium, the polymerization time of one batch is greatly reduced, and at the same time, a high-quality vinyl-based polymer having less fish eyes, good plasticizer absorption and demonomerization properties is obtained. It was found that coalescence was obtained. Furthermore, when a vinyl compound such as vinyl chloride is subjected to suspension polymerization, the water-insoluble polymer having an SH group at one end at a specific point in time at a relatively low polymerization rate at a specific ratio to the vinyl compound. It has been found that the thermal stability can be remarkably improved without impairing the stability of suspension polymerization and the processing characteristics of the resin by adding it to the polymerization system. The present invention has been made based on such findings.

That is, the present invention relates to a polymerization initiator and a polymerization initiator.
Heat vinyl compound to 40 ° C or higher in the presence of powder stabilizer
When suspension polymerization is carried out by adding a prepared aqueous medium, it is composed of radically polymerizable monomer units, and SH is provided at one end.
A water-insoluble compound represented by the general formula Z-SH (I) wherein Z represents a polymer component composed of one or more monomer units capable of radical polymerization. An object of the present invention is to provide a method for producing a vinyl polymer, which comprises using a dispersion aid for suspension polymerization of a vinyl compound composed of a polymer. Further, the present invention provides a method for suspension-polymerizing a vinyl compound in an aqueous medium in the presence of a polymerization initiator and a dispersion stabilizer. And 20 to 100 parts by weight of a water-insoluble polymer having an SH group at one end represented by the general formula (I) is added to the polymerization system. Things.

The dispersing aid of the present invention is a polymer having an SH group at one terminal represented by the general formula Z-SH (I) and must be water-insoluble. The Z component is composed of one or more monomer units capable of radical polymerization, and may have a graft structure. The Z component is composed of one or more monomer units capable of radical polymerization (co).
Although it is a polymer, various monomers can be used as the radical polymerizable monomer. Preferred examples include (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylic acid amide, vinyl ester, vinyl ether, α-olefin, and derivatives thereof. Examples of the (meth) acrylate 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)
And stearyl acrylate and behenyl (meth) acrylate. Examples of the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, and palmitic acid. Vinyl, vinyl stearate, vinyl oleate and the like. When this vinyl ester is used after being saponified, the saponification degree is desirably adjusted to 50 mol% or less. Examples of the vinyl ether include methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether. Further, examples of the α-olefin and derivatives thereof include ethylene, propylene, isoprene, styrene, acrylonitrile, and vinyl chloride.

The (co) polymer used as the dispersing aid of the present invention preferably has an average degree of polymerization (Pn) of 5000 or less. The production method of this (co) polymer is not particularly limited 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 allocated. However, in various methods, when radical-polymerizing a monomer, thiolcarboxylic acid or 2-acetylthioethylthiol,
Polymerization is carried out in the presence of a compound containing a thioester and a thiol group in a molecule such as 0-acetylthiodecanethiol, and the obtained polymer is treated with an alkali such as sodium hydroxide or ammonia to form a thiol at one end. The method for obtaining a polymer having a group is most preferable as a method for obtaining a (co) polymer used as a dispersing aid of the present invention simply and efficiently.

In the present invention, as a method for producing a vinyl polymer, first, when a vinyl compound is subjected to suspension polymerization in the presence of a polymerization initiator and a dispersion stabilizer, an aqueous solution heated to a polymerization reaction system is used. By introducing the above-mentioned dispersing aid together with the medium, the polymerization time of one batch can be significantly reduced, and at the same time, a high-quality vinyl polymer having few fish eyes and good plasticizer absorption and demonomerization properties can be obtained. In the method for producing, when the polymerization rate is relatively low when the vinyl compound is suspension-polymerized in the presence of the polymerization initiator and the dispersion stabilizer, the water represented by the above general formula Z-SH A method for producing a vinyl polymer having significantly 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 dispersing aid used is not particularly limited.
It is preferably at most 5 parts by weight, more preferably at most 1 part by weight, based on 00 parts by weight. In suspension polymerization of a vinyl compound using the dispersing aid, the production method is not particularly limited, and a conventionally known method can be used. As the dispersion stabilizer to be used, those which are usually used when suspension-polymerizing a vinyl compound such as vinyl chloride in an aqueous medium may be used, and examples thereof include methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and hydroxypropyl. Water-soluble cellulose ethers such as methylcellulose, partially saponified polyvinyl alcohol (degree of saponification 60 to 95 mol%, average polymerization degree 500 or more) and modified products of this ionic group or nonionic group, low saponification degree PVA (less than 60 mol% saponification, average Polymerization degree of 3,000 or less) and modified products of ionic or nonionic groups, water-soluble polymers such as gelatin, sorbitan monolaurate, sorbitan triolate, glycerin tristearate, ethylene oxide propylene oxide block copolymer, 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 parts by weight per 100 parts by weight of a vinyl compound such as vinyl chloride.

Other various additives can be added as needed. Examples of various additives that can be used include polymerization degree regulators such as acetaldehyde, butyraldehyde, trichloroethylene, perchloroethylene and mercaptans, phenol compounds, sulfur compounds, N-
There are polymerization inhibitors such as oxide compounds. Also, p
It is optional to add an H regulator, a scale inhibitor, a crosslinking agent, and the like, and a plurality of the above additives may be used in combination. It is also effective to attach a condenser such as a condenser to the polymerization apparatus.

On the other hand, the polymerization initiator may be any of those conventionally used for the polymerization of vinyl compounds such as vinyl chloride.
For example, percarbonate compounds such as diisopropylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, diethoxyethylperoxydicarbonate, t-butylperoxyneodecanate, α-cumylperoxyneodecanate , T-
Perester compounds such as butylperoxyneodecanate, peroxides such as acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, and 2,2'-azobisisobutyronitrile And azo compounds such as azobis-2,4-dimethylvaleronitrile, azobis (4-methoxy-2,4-dimethylvaleronitrile), and potassium persulfate, ammonium persulfate, hydrogen peroxide and the like. They can be used in combination. This amount is preferably in the range of 0.02 to 0.3 parts by weight per 100 parts by weight of a vinyl compound such as vinyl chloride.

There are various types of vinyl compounds which can be subjected to suspension polymerization using the dispersing aid of the present invention. Specifically, in addition to vinyl chloride alone, a vinyl chloride-based monomer The mixture includes a mixture (50% by weight or more of vinyl chloride). Examples of the comonomer copolymerized with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate, methyl (meth) acrylate, and ethyl (meth) acrylate. (Meth) acrylate, ethylene,
Olefins such as propylene, maleic anhydride, acrylonitrile, itaconic acid, styrene, vinylidene chloride,
Examples thereof include vinyl ether and other monomers copolymerizable with vinyl chloride. Further, the dispersing aid of the present invention can be used for homopolymerization or copolymerization of the above-mentioned vinyl compound containing no vinyl chloride. In the suspension polymerization using the dispersing agent of the present invention, the charge ratio of each component, the polymerization temperature and the like are determined according to the conditions conventionally used in the suspension polymerization of vinyl compounds such as vinyl chloride. Well, there is no particular limitation.

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 uses the above-described Z-SH type of the present invention as a dispersing aid. A dispersing aid composed of a (co) polymer is used. The heating aqueous medium used here has a temperature of 40 ° C. or higher, and there is no particular upper limit, and hot water of 95 ° C. or higher may be used. The medium constituting the heated aqueous medium is not limited to pure water, but may be any aqueous solution containing various additive components, an aqueous medium containing other organic solvents, or any medium that does not hinder suspension polymerization of vinyl compounds. For example, various aqueous media can be mentioned. Also,
The supply amount when the heated aqueous medium is charged into 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 the vinyl compound to be polymerized, the type of the polymerization initiator to be used, and the type of the dispersion stabilizer are not particularly limited, and are appropriately selected from those already described above. Also, vinyl compounds, polymerization initiators,
The order and ratio of the dispersion stabilizer, the heated aqueous medium and the other additives are not limited at all. The vinyl polymer obtained in this way has a sharp particle size distribution of particles, little fisheye, good plasticizer absorption and demonomerization properties, a large filling specific gravity, and thermal stability. And excellent gelling properties. Further, according to the above-mentioned polymerization method, there is no adhesion of scale to a polymerization tank or the like, and the polymerization time of one batch can be greatly reduced.

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

Various rubber components can be added to a vinyl polymer such as a vinyl chloride resin obtained by the method of the present invention, if necessary. 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. Terpolymer, butadiene-isoprene-butadiene terpolymer and the like. 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 stearins Lead acid,
Inorganic stabilizers such as calcium hydroxide and calcium silicate, as well as lubricants, pigments, fillers, impact modifiers, processing aids, ultraviolet absorbers and the like may be added later.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In the following examples, “%” and “parts” are “% by weight” unless otherwise specified.
And "parts by weight". Production Example 1 [Production of polymethyl methacrylate having a mercapto group at a terminal] Methyl methacrylate (hereinafter abbreviated as MMA)
290 parts and 4.6 parts of thioacetic acid were placed in a reaction vessel, and the inside was sufficiently purged with nitrogen.
MMA containing 0.3 part of 2'-azobisisobutyronitrile
Polymerization was carried out by adding 10 parts. The polymerization rate after 1.5 hours is 7
8.8%. After the polymerization, the content was diluted with acetone and poured into n-hexane to precipitate and precipitate the polymer. The precipitate was reprecipitated three times with acetone and water, and the unreacted MM was obtained.
A was removed. Next, 200 g of this polymer was added to acetone 3
Dissolved in a mixed solvent of 20 g and 80 g of methanol to give a concentration of 1
12 g of 0% methanol solution of NaOH was added,
For 2.5 hours. Subsequently, it 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 sufficiently with water and dried, and poly (methyl methacrylate) having a mercapto group at one end was obtained. Below P
MMA). When this PMMA was measured for intrinsic viscosity number [η] at 30 ° C. in acetone, [η] = 0.06 (dl / g), and the amount of mercapto group was determined by titration with iodine in an acetone-water system. 9.9
It was 9 × 10 ⁻⁵ eq / g.

Production Example 2 [Production of polystyrene having a mercapto group at the end] 9.8 g of a 10% thioacetic acid toluene solution was added to 1200 g of styrene, and 2,2'-azobisisobutyi was used as a polymerization initiator. 0.35 g of lonitrile was added, and the temperature was 70 ° C.
Was polymerized. After the polymer obtained at a conversion rate of 25% was purified by reprecipitation in methanol, unreacted styrene monomer was removed by methanol soxhlet. 30 g of the obtained polymer was dissolved in 90 g of toluene, and 70 g of
At 16 ° C., 0.16 g of a 10% NaOH methanol solution was added and reacted for 2 hours. After neutralization with acetic acid, it was sufficiently washed with water and dried to obtain polystyrene having a mercapto group at one end (hereinafter abbreviated as PSt).

Reference Example 1A PVA having a saponification degree of 85 mol% and an average degree of polymerization of 2500
The suspension polymerization of vinyl chloride was carried out using 0.06 parts of a dispersing agent (dispersion stabilizer) consisting of and 0.03 parts of a dispersing aid consisting of a polymer of PMMA-SH obtained according to the above Production Example. The procedure was as follows. In the following Examples and Comparative Examples, the amounts of the dispersing agent, the dispersing aid, and the Z-SH polymer used are based on 100 parts by weight of vinyl chloride. That is, in a glass-lined autoclave, 40 parts of deionized water, 0.06 part of the above dispersant, and 0.1 part of the above dispersing aid were added.
03 parts and 0.009 part of a 50% toluene solution of diisopropyl peroxydicarbonate were charged, and the inside of the autoclave was degassed until the pressure became 50 mmHg to remove oxygen. Then, 30 parts of vinyl chloride was charged, and the mixture was heated to 57 ° C under stirring. The temperature was raised to perform polymerization. At the start of polymerization, the pressure in the autoclave was 8.0 kg / cm ² G, because after polymerization initiation 6 hours became 5.0 kg / cm ² G to stop the polymerization 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 dispersant (dispersion stabilizer) and the dispersion aid used in the suspension polymerization, and Table 2 shows the performance of the obtained vinyl chloride resin. The polymerization yield of the vinyl chloride resin was 85%, and the average degree of polymerization was 1,100.

Reference Examples 2A to 20A and Comparative Examples 1A to 7A In the same manner as in Example 1A except that the types and amounts of the dispersant (dispersion stabilizer) and the dispersing aid were changed as shown in Table 1, Suspension polymerization of vinyl chloride was performed. Table 2 shows the performance of the obtained vinyl chloride resin.

[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: n-acrylic acid 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 metal mesh based on Tyler mesh. (2) Fisheye measurement method 100 parts of vinyl chloride resin obtained by polymerization, 1 part of tribasic lead sulfate, 1.5 parts of lead stearate, 0.2 parts of titanium dioxide
Part, carbon black 0.1 part, dioctyl phthalate 5
0 composition was mixed parts 25g were kneaded for 5 minutes at 145 ° C. rolls, aliquoted as a 0.2mm thick sheet, indicated with the number of transparent particles of the seat 100 cm ^2. (3) Plasticizer absorptivity In a planetary mixer connected to a plastograph,
400 g of the vinyl chloride resin powder obtained by the polymerization is added, and the mixture is preheated (4 minutes) while stirring at 60 rpm, and is heated to 80 ° C.
After that, 200 g of dioctyl phthalate was added thereto, and the time until the torque decreased due to the addition was defined as plasticizer absorbency (minutes). (4) Residual vinyl chloride monomer The content of the vinyl chloride monomer in the vinyl chloride resin was determined by head space gas chromatography. (5) Thermal stability (colorability) test: vinyl chloride resin 100
Parts, 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) Gelling properties 65 g of the same composition as in the above fisheye measurement
Into a plastograph (50-type kneader) at a temperature of 19
The stirring was started under the condition of the rotation speed of 0 ° C. and the rotation speed of 60 rpm, and the time (min) until the maximum torque was shown was set.

Examples 1B to 20B and Comparative Examples 1B to 7B In the above Reference 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 the charging was 57 ° C. The suspension polymerization of vinyl chloride was carried out under the same conditions except for the above. Table 3 shows the performance of the obtained vinyl chloride resin. It should be noted that A and B of the same embodiment and reference example correspond to each other, and A and B of the same comparative example correspond to each other.

[0040]

[Table 11]

[0041]

[Table 12]

[0042]

[Table 13]

[0043]

[Table 14]

Examples 21 to 30 and Reference Example 21 The suspension polymerization of vinyl chloride was carried out by the following method. That is, 50 g of deionized water is added to the glass lining autoclave.
Parts, a dispersant and 0.009 part of a 50% toluene solution of diisopropyl peroxydicarbonate were charged, and the inside of the autoclave was degassed until the pressure became 50 mmHg to remove oxygen.
The temperature was raised to ° C. to perform 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 is 8.0 kg / cm ²
G, but 5.0 kg / cm ² 6 hours after the start of polymerization.
At this point, the polymerization was stopped, the unreacted vinyl chloride monomer was purged, and the contents were taken out and dehydrated and dried. Dispersant (dispersion stabilizer) used for suspension polymerization and Z-
Table 4 shows the type and amount of the SH type polymer and the timing of addition of the Z-SH type polymer, and Table 5 shows the performance of the vinyl chloride resin.

[0045]

[Table 15]

[0046]

[Table 16]

EVA: ethylene-vinyl acetate The symbols for the other monomer components are the same as those in Table 1 footnotes.

[0048]

[Table 17]

[0049]

[Table 18]

(1) Average Particle Size The average particle size was measured by dry knot analysis using a metal rope based on Tyler mesh. (2) Thermal stability After the vinyl chloride resin obtained by the suspension polymerization was dried at 65 ° C. for 8 hours, the resin particles were heated in a hot block bath at 185 ° C., and the degree of coloring was visually determined as follows. The evaluation was made according to criteria. ◎: no coloring ○: slightly colored △: colored pink ×: colored red to brown

[0051] Instead of Comparative Example 8 to 10 Z-SH-type polymer, or using a polymer having no SH groups as shown in Table 6, or without using a polymer, Example 21-30 The suspension polymerization of vinyl chloride was carried out in the same manner as described above. Table 6 shows the types and amounts of the dispersant (dispersion stabilizer) and the added polymer used in the suspension polymerization, and the timing of addition 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 thermal stability is the same as the footnote in Table 5.

[0052]

[Table 19]

[0053]

[Table 20]

[0054]

The dispersing aid of the present invention has a very high ability to make the vinyl polymer particles formed porous compared to conventional dispersing aids, has a high plasticizer absorption rate, and remains. Excellent performance, such as providing a vinyl polymer from which unreacted vinyl monomers can be easily removed. In addition, the obtained vinyl polymer particles are excellent in various points, such as a large particle size, a sharp distribution, small scattering during handling, and good penetration into molding machines. is there. In addition, according to the method for producing a vinyl polymer of the present invention using the dispersing agent, the polymerization time of one batch can be significantly reduced, and, over a wide variety of grades, the number of fish eyes is small and the plasticizer is reduced. It is possible to obtain a high quality vinyl polymer having good absorbability and good demonomerization properties. Furthermore, by adding a polymer having an SH group at one end to the polymerization system at a relatively low polymerization rate in a relatively large amount, a vinyl polymer having extremely excellent thermal stability can be produced.

────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference European Patent Application Publication No. 483051 (EP, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/18-2/20

Claims (2)

(57) [Claims] (1) In the presence of a polymerization initiator and a dispersion stabilizer,
In suspension polymerization of a vinyl compound by adding an aqueous medium heated to 40 ° C. or higher, a monomer unit capable of radical polymerization is used.
Consists position, and in the general formula Z-SH (formula having SH group at one terminal, Z also one radical polymerizable monomer unit
Represents a polymer component composed of two or more kinds. ) Of a vinyl compound composed of a water-insoluble polymer
A method for producing a vinyl polymer, comprising using a dispersing aid for suspension polymerization . 2. In the presence of a polymerization initiator and a dispersion stabilizer,
In suspension polymerization of a vinyl compound in an aqueous medium,
When the polymerization rate is 60% or less, the vinyl compound 100
The general formula Z-SH (wherein Z is one or more radical-polymerizable monomer units, which is composed of a radical-polymerizable monomer unit and has an SH group at one end with respect to parts by weight) A method for producing a vinyl polymer, comprising adding 20 to 100 parts by weight of a water-insoluble polymer represented by the following formula (1) to a polymerization system.