JPH11106408A - Suspension polymerization of vinyl chloride monomer - Google Patents

Abstract

(57) [Summary] [Problem] There is no adhesion of resin scale on the inner wall of a polymerization vessel, and the obtained vinyl chloride resin has a sharp particle size distribution and a high bulk specific gravity. Provided is a method for suspension polymerization of a vinyl chloride monomer having excellent moldability. When a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator, a partially saponified polyvinyl acetate (a) and a cellulose derivative (b) are added to the reaction system. ), At least one emulsifier of higher fatty acid ester (c) of sorbitan (c) and anionic emulsifier (d), higher fatty acid (e), and thickener (f) are added. After the polymerization is started, when the weight ratio of the vinyl chloride monomer / aqueous medium falls within a certain range, a nitrogen-containing compound (g) is further added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suspension polymerization of vinyl chloride monomers.

[0002]

2. Description of the Related Art Conventionally, vinyl chloride resins have been used in many applications as materials having excellent mechanical strength, weather resistance and chemical resistance. However, the vinyl chloride resin is not always good in moldability, and further improvement is demanded. In general, measurement of a plasticizer absorption amount, measurement of torque and gel time by a plast mill, and the like are performed as typical scales for evaluating the moldability of a vinyl chloride resin. With respect to the amount of plasticizer absorbed, the moldability is better as the plasticizer penetrates into the vinyl chloride resin in a shorter time, and the maximum torque is lower with respect to plastmill, and the shorter the gelation time, the better the moldability. Have been.

[0003] There are several possible factors which impair the moldability, and one of the major factors is the presence of skin on the surface of vinyl chloride resin particles. The skin means a skin layer present on the surface of the vinyl chloride resin particles, the main component of which is a dispersant (for example, partially saponified polyvinyl acetate, a cellulose derivative, etc.) used for polymerization, or a material such as vinyl chloride. It is considered to be a layer firmly grafted to the base resin.

[0004] Originally, the skin is considered to have a role of protecting the surface of the monomer oil droplets in the polymerization system, regulating the splitting and coalescence of the oil droplets, and stabilizing the polymerization system. However, on the other hand, it is necessary to grind the vinyl chloride resin particles to sub-micron units (primary particles or less) at the stage of molding and processing the vinyl chloride resin. Have been.

[0005] In view of the above, in order to obtain vinyl chloride resin particles having excellent moldability, it is preferable that the skin on the surface is not present or is extremely small even if it is present. Incorporated liquid stabilizer,
It is considered that it is important that there are many primary particles between the primary particles inside the vinyl chloride resin particles because the plasticizer and the like are easily diffused and absorbed.

As a method for producing a vinyl chloride resin having excellent moldability as described above, for example, JP-B-36-22
No. 445 discloses a suspension polymerization method in which a higher fatty acid ester of sorbitan and a higher fatty acid ester of polyoxyethylene sorbitan are used in combination. However,
According to this method, the obtained vinyl chloride resin has poor porosity, a large percentage of the remaining skin, and a large amount of polymer scale adheres to the inner wall of the polymerization vessel.

Many studies have been made to solve the above problems. For example, Japanese Patent Publication No. 53-13395
JP-A No. 2000-209, use a dispersant in which a lipophilic sorbitan higher fatty acid and a hydrophilic polyoxyethylene sorbitan higher fatty acid ester are combined in the presence of a basic compound, and the polymerization conversion of vinyl chloride is reduced to 5 to 40%. A method of adding a water-soluble cellulose derivative when it is reached is disclosed.
For example, in Japanese Patent Publication No. 5-86408, a higher fatty acid ester of sorbitan is used as a dispersant, and polymerization is started under stirring by a Faudler blade, and when the polymerization conversion reaches 5 to 40%, a water-soluble polymer is obtained. A method of adding a dispersant is disclosed.

However, in the above two polymerization methods,
No resin scale adheres to the inner wall of the polymerization vessel during the polymerization reaction,
Porous vinyl chloride resin particles can be obtained, but the bulk specific gravity becomes low, the operation becomes complicated in the polymerization step to add the dispersant afterwards, and the dispersant is added to the surface of the vinyl chloride resin particles. There was a problem that a large amount of the resin remained, deteriorating the physical properties of the obtained vinyl chloride resin.

For example, in Japanese Patent Application Laid-Open No. 5-295008, a known suspending and dispersing agent, a non-ionic surfactant such as partially saponified polyvinyl acetate having a low degree of saponification and monosorbitan laurate are used at a specific ratio. And a method for carrying out polymerization. However, in this method, although the skin portion on the surface of the vinyl chloride resin is surely reduced, the operation becomes complicated due to the necessity of controlling the power required for stirring in the initial stage of polymerization, and the gel of the obtained vinyl chloride resin is gelled. The chemical properties, plasticizer absorbency, etc., were not yet satisfactory.

Further, JP-A-8-59731 discloses a method of polymerizing a suspension dispersant or a cellulose derivative having a specific cloud point, a specific thickener and a higher fatty acid having 8 to 25 carbon atoms in combination. In these methods, since the additives can be added all at once, there is no complexity in the manufacturing process,
Although the effect of removing the skin portion of the vinyl chloride resin particles was recognized, the moldability was not sufficient.

Further, in Japanese Patent Application Laid-Open No. Hei 8-3206,
Although a method using partially saponified polyvinyl alcohol and high-viscosity hydroxypropylmethylcellulose is disclosed, although the plasticizer absorbency of the obtained vinyl chloride resin is excellent, it is not satisfactory because the bulk specific gravity is low. Was.

As described above, in the prior art, a decrease in bulk specific gravity was unavoidable in the case of a vinyl chloride resin having no skin. Accordingly, there has been a demand for an improvement in productivity per volume of the polymerization tank and a measure for preventing scale while improving the bulk specific gravity.

As one of the solutions, a method of adding a water-soluble polymerization inhibitor is disclosed in, for example, JP-A-63-8310.
No. 1, JP-A-3-275704, JP-A-8-
No. 217806. JP-A-63-8
No. 3101 exemplifies, as a polymerization inhibitor, hydroxyl-containing compounds such as diethylhydroxylamine or hindered phenols represented by BHT, and nitrites such as sodium nitrite.

JP-A-3-275704 exemplifies, as a polymerization inhibitor, a nitrite such as sodium nitrite, a thiocyanate such as ammonium thiocyanate, and a water-soluble sulfur-containing organic compound such as thioethanolamine. ing. Further, nitrites such as sodium nitrite and ammonium nitrite, thiocyanates such as ammonium thiocyanate and zinc thiocyanate, and water-soluble organic compounds containing sulfur such as mercaptoethanol are exemplified.

However, the purpose of adding these polymerization inhibitors is to halt the progress of polymerization outside the oily interior where polymerization should not normally proceed, to improve bulk specific gravity and to prevent scale. It was not a satisfactory level in increasing the specific gravity.

In Japanese Patent Application Laid-Open No. 4-325506, a specific dispersant is used, and an aqueous medium is added during the polymerization to produce a vinyl chloride resin with less generation of fish eyes when a plasticizer is absorbed. A way to do that has been proposed. However, this method has not improved the bulk specific gravity or the plasticizer absorption.

Furthermore, Japanese Patent Application Laid-Open No. Hei 8-100004 discloses that a specific heat exchanger is used for removing heat of reaction, and an aqueous medium corresponding to the volume reduced by polymerization is added to improve productivity. Although the aim is to prevent scale, the improvement in the bulk specific gravity has been insufficiently improved.

As a solution other than the above, for example, in Japanese Patent Application Laid-Open No. 61-195101, a vinyl chloride monomer is additionally charged during a specific polymerization addition ratio to improve productivity and improve bulk specific gravity. Although a method for improving the performance is disclosed, there are problems in scale adhesion and moldability.

[0019]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vinyl chloride resin which has no resin scale adhered to the inner wall of a polymerization vessel and has a sharp particle size distribution and a high bulk specific gravity. An object of the present invention is to provide a method for suspension polymerization of a vinyl chloride monomer, which has almost no skin portion and has excellent moldability.

[0020]

The suspension polymerization method of a vinyl chloride monomer according to the first aspect of the present invention (hereinafter referred to as the first invention) is characterized in that the vinyl chloride monomer is oil-soluble. When suspension polymerization is carried out in an aqueous medium in the presence of a polymerization initiator, at least one dispersant of partially saponified polyvinyl acetate (a) and cellulose derivative (b) is added to the reaction system,
At least one emulsifier of a sorbitan higher fatty acid ester (c) having a value of 3 to 10 and an anionic emulsifier (d), a higher fatty acid having 8 to 25 carbon atoms (e), and 0.1 wt. % Of aqueous solution having a Brookfield viscosity of 10 to 200 cps to initiate polymerization, and then a vinyl chloride monomer / aqueous medium weight ratio of 1.1 to 0.3 Then, a water-soluble nitrogen-containing compound (g) having a molecular weight of 50 to 300 and having at least one nitrogen atom is added, and the nitrogen-containing compound (g) is added.
Is from 30 to 500 ppm based on the vinyl chloride monomer present at that time.

The invention according to claim 2 of the present invention (hereinafter referred to as the second
The invention is a method of suspension polymerization of a vinyl chloride monomer, the vinyl chloride monomer in the presence of an oil-soluble polymerization initiator,
At the time of suspension polymerization in an aqueous medium, a dispersant of at least one of partially saponified polyvinyl acetate (a) and a cellulose derivative (b), a sorbitan higher fatty acid having an HLB value of 3 to 10 is added to the reaction system. At least one emulsifier of ester (c) and anionic emulsifier (d), having 8 to 2 carbon atoms
And a 0.1% by weight aqueous solution having a Brookfield viscosity of 10 to 10 at room temperature and normal pressure.
After adding 200 cps of the thickener (f) to start the polymerization, the weight ratio of vinyl chloride monomer / aqueous medium is 0.1%.
At the time of 8-0.3, further aqueous medium (h) is added,
The amount of the aqueous medium (h) to be added is 0.05 to 1 in weight ratio to the vinyl chloride monomer 1 present at that time.

The invention according to claim 3 of the present invention (hereinafter referred to as "third")
The invention is a method of suspension polymerization of a vinyl chloride monomer, the vinyl chloride monomer in the presence of an oil-soluble polymerization initiator,
At the time of suspension polymerization in an aqueous medium, a dispersant of at least one of partially saponified polyvinyl acetate (a) and a cellulose derivative (b), a sorbitan higher fatty acid having an HLB value of 3 to 10 is added to the reaction system. At least one emulsifier of ester (c) and anionic emulsifier (d), having 8 to 2 carbon atoms
And a 0.1% by weight aqueous solution having a Brookfield viscosity of 10 to 10 at room temperature and normal pressure.
After adding 200 cps of the thickener (f) to start the polymerization, the weight ratio of vinyl chloride monomer / aqueous medium is 0.1%.
At the time of 8 to 0.3, an aqueous medium (i) containing an antifoaming agent is further added, and the amount of the aqueous medium (i) added to the vinyl chloride monomer 1 existing at that time is changed. On the other hand, the weight ratio is 0.05 to 1.

The invention according to claim 4 of the present invention (hereinafter referred to as the fourth
The invention is a method of suspension polymerization of a vinyl chloride monomer, the vinyl chloride monomer in the presence of an oil-soluble polymerization initiator,
At the time of suspension polymerization in an aqueous medium, a dispersant of at least one of partially saponified polyvinyl acetate (a) and a cellulose derivative (b), a sorbitan higher fatty acid having an HLB value of 3 to 10 is added to the reaction system. At least one emulsifier of ester (c) and anionic emulsifier (d), having 8 to 2 carbon atoms
And a 0.1% by weight aqueous solution having a Brookfield viscosity of 10 to 10 at room temperature and normal pressure.
After adding 200 cps of the thickener (f) to start the polymerization, the weight ratio of vinyl chloride monomer / aqueous medium is 0.1%.
At the time of 7 to 0.4, an aqueous medium (j) containing the above-mentioned thickener (f) is further added, and the amount of the aqueous medium (j) added depends on the amount of the vinyl chloride-based monomer present at that time. It is characterized in that the weight ratio with respect to the body 1 is 0.1 to 1.

The invention according to claim 5 of the present invention (hereinafter referred to as the fifth
The invention is a method of suspension polymerization of a vinyl chloride monomer, the vinyl chloride monomer in the presence of an oil-soluble polymerization initiator,
At the time of suspension polymerization in an aqueous medium, a dispersant of at least one of partially saponified polyvinyl acetate (a) and a cellulose derivative (b), a sorbitan higher fatty acid having an HLB value of 3 to 10 is added to the reaction system. At least one emulsifier of ester (c) and anionic emulsifier (d), having 8 to 2 carbon atoms
And a 0.1% by weight aqueous solution having a Brookfield viscosity of 10 to 10 at room temperature and normal pressure.
After adding 200 cps of the thickener (f) to start the polymerization, the weight ratio of vinyl chloride monomer / aqueous medium is 0.1%.
At the time of 8 to 0.3, the vinyl chloride monomer and the aqueous medium (j) containing the thickener (f) are further added, and the vinyl chloride monomer and the aqueous medium (j) are added. Is added in a weight ratio of 0.05 to 1 with respect to the vinyl chloride monomer 1 present at that time.

Hereinafter, the first invention will be described. In the suspension polymerization method of the first invention, when a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator, a partially saponified polyvinyl acetate (a) and a cellulose derivative are used. (B) at least one dispersant, sorbitan higher fatty acid ester (c) and anionic emulsifier (d), at least one emulsifier, higher fatty acid (e), and thickener (f) To initiate polymerization.

In the suspension polymerization method of the first invention, at least one of partially saponified polyvinyl acetate (a) and cellulose derivative (b) is used as a dispersant.

The partially saponified polyvinyl acetate (a) is
When the saponification degree is low, the oil solubility becomes strong, and the ability to disperse the vinyl chloride monomer is insufficient, so that the obtained vinyl chloride resin (hereinafter referred to as PVC) has a large number of coarse particles, and when it is high, the protection is high. Since a strong skin portion is formed on the surface of the obtained PVC due to an increase in the colloidal properties and the gelling property is reduced, the content is preferably 60 to 90 mol%, more preferably 70 to 85 mol%.

When the average degree of polymerization of the partially saponified polyvinyl acetate (a) is low, the dispersing ability of the vinyl chloride monomer is lacking, so that the PVC tends to be coarse particles or blocks, and when the average polymerization degree is high, the PVC particles obtained are high. The thickness is preferably from 500 to 3,000, more preferably from 7 to 7, since the skin layer becomes thicker and the porosity becomes insufficient, and the moldability decreases.
00 to 1,500.

The partially saponified polyvinyl acetate (a) is
They may be used alone or in combination of two or more.

When the amount of the partially saponified vinyl acetate (a) is too small, the oil droplets of the vinyl chloride monomer are unstable, so that the PVC tends to be in a block shape. Since it becomes thicker and the molding processability deteriorates, it is 150 to 2.0 with respect to the vinyl chloride monomer.
00 ppm is preferred.

As the above-mentioned cellulose derivative (b),
Examples include methylcellulose, ethylcellulose, hydroxypropylmethylcellulose, and hydroxyethylcellulose, and these may be used alone or in combination of two or more.

If the amount of the above-mentioned cellulose-based derivative (b) is too small, the oil droplets become unstable, so that the PVC may become blocky. If the amount is too large, the skin layer on the PVC surface becomes thick, and sometimes the fish is added. Glass bead-shaped particles called "eye" increase and molding processability deteriorates.
ppm is preferable, and more preferably 80 to 1,500 p
pm.

In the suspension polymerization method of the first invention, at least one of sorbitan higher fatty acid ester (c) and anionic emulsifier (d) is used as an emulsifier, and both may be used in combination.

The above sorbitan higher fatty acid ester (c)
When the HLB value of the vinyl chloride monomer decreases, the dispersing ability of the vinyl chloride monomer in an aqueous medium decreases due to strong lipophilicity.
The obtained PVC has a wide particle size distribution including coarse particles, and the higher the viscosity, the stronger the hydrophilicity, so that the oil droplets of the vinyl chloride monomer during polymerization become unstable, and the aggregation of the monomer particles and Coalescence is likely to occur, and the resulting PVC will be an aggregate of block-like or coarse particles, and is therefore limited to 3 to 10, and preferably 4 to 9.

The HLB (hydrophilic-lipophilic equilibrium) is defined as WCGr
iffin [J. Soc. Cosmetic Chem., Vol. 1, p. 311;
9)] means the balance between the hydrophilic group and the hydrophobic group of the nonionic surfactant. The larger the value, the greater the hydrophilicity, and the smaller the value, the greater the hydrophobicity.

The sorbitan higher fatty acid ester (c) having the above HLB value includes sorbitan monolaurate (HLB value 8.6), sorbitan monomyristate, sorbitan monopalmitate (HLB value 5.6), sorbitan monostearate Sorbitan saturated higher fatty acid esters such as citrate (HLB value 4.7), sorbitan distearate (HLB value 4.4) and sorbitan tristearate (HLB value 2.1); and unsaturated higher fatty acid esters. May be used alone or in combination of two or more.

The above sorbitan higher fatty acid ester (c)
When the amount of addition is small, the skin of the obtained PVC particles becomes thick and the porosity is insufficient, so that the moldability is not improved. When the amount is large, the particle size distribution of the obtained PVC particles becomes wide and the polymer on the inner wall of the polymerization vessel becomes large. Since the amount of scale attached increases, the amount of the vinyl chloride monomer is 500 to 5,
000 ppm is preferred, and more preferably 800 to 2,
500 ppm.

Examples of the anionic emulsifier (d) include fatty acid salts such as sodium stearate soap; alkyl sulfate salts such as sodium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate; sodium octylnaphthalene sulfonate; Alkyl naphthalene sulfonates; alkyl sulfo succinates such as sodium didodecyl sulfosuccinate, as well as alkyl diphenyl ether disulfonates, alkyl phosphates,
Polyoxyethylene alkyl sulfates, formalin condensates of naphthalenesulfonic acid, special polycarboxylic acid type polymer surfactants, polyoxyethylene alkyl phosphates, reactive surfactants, etc., which are used alone And two or more of them may be used in combination.

The amount of the anionic emulsifier (d) added is
If the amount is small, the skin portion of the PVC is formed thick and the porosity is insufficient, so there is no effect of improving the moldability.If the amount is large, the particle size distribution of the PVC is widened and the amount of polymer scale attached to the inner wall of the polymerization vessel increases, In some cases, the PVC becomes block-shaped, so the amount is preferably 5 to 1,000 ppm, more preferably 25 to 750 ppm, based on the vinyl chloride monomer.

When the carbon number of the higher fatty acid (e) used in the first invention is reduced, the higher fatty acid (e) has a water-soluble property and is not distributed to an oil layer such as a vinyl chloride monomer during polymerization. Since the melting point of the higher fatty acid (e) increases when the content increases, it is difficult to exhibit the gelation promoting effect at the molding temperature. Therefore, it is limited to 8 to 25, and preferably 11 to 22.

The higher fatty acid having 8 to 25 carbon atoms (e) includes, for example, isostearic acid, stearic acid, n
-Heptadecanoic acid, palmitic acid, n-pentadecanoic acid, myristic acid, arginic acid, nonadecanoic acid, n-tridecanoic acid, lauric acid, undecylic acid and the like,
These may be used alone or in combination of two or more. As the higher fatty acid (e), the effect is not reduced by the degree of unsaturation and branching of the main chain, but it is particularly preferable to use a linear saturated fatty acid.

If the amount of the higher fatty acid (e) is too small, no effect can be obtained, and if it is too large, the gelation time is delayed.
00 ppm is preferred.

The thickener (f) used in the first invention is used for imparting a thickening effect to the reaction system. When the viscosity of the aqueous solution decreases, a sufficient thickening effect is exhibited during the reaction. Therefore, the particle size distribution of PVC becomes coarse, and if it becomes high, the aggregation state in the polymerization system changes, and coarse particles of 500 μm or more increase. “Η”) is limited to 10 to 200 cps (mPa), and is preferably 11 to 140 cps.

As the thickener (f) in which η is 10 to 200 cps, for example, polyethylene oxide,
Polyvinylpyrrolidone, polyacrylamide, polyacrylamide copolymer, crosslinked (meth) acrylic acid-based polymer, methylcellulose calcium, sodium starch glycolate, sodium starch phosphate, sodium alginate, propylene glycol alginate, sodium carboxymethylcellulose, carboxymethylcellulose calcium These may be used alone or in combination of two or more.

Among the above thickeners (f), the average molecular weight of polyethylene oxide is preferably 1.7 million to 5.5 million, and particularly when polyethylene oxide having an average molecular weight of 4.3 million to 4.8 million is used, η becomes 51 cps.

If the amount of the thickener (f) is too small, a sufficient thickening effect is not exhibited in the reaction system, so that the particle size distribution of PVC becomes coarse, and if it is too large, the PVC surface is covered with a strong skin layer. Since the gelation rate becomes slow, the content is preferably 5 to 2,000 ppm, more preferably 25 to 900 ppm, based on the vinyl chloride monomer.

In the suspension polymerization method of the first invention, a nitrogen-containing compound (g) is further added when the weight ratio of vinyl chloride monomer / aqueous medium is 1.1 to 0.3.

The nitrogen-containing compound (g) is a water-soluble compound having at least one nitrogen atom and having a molecular weight of 50 to 300. When the molecular weight of the nitrogen-containing compound (g) is less than 50, the action of the emulsifiers (c) and / or (d) near the oil droplet interface is hindered, and particles without skin cannot be stably present. The compound (g) has a molecular weight of 3
If it exceeds 00, the action of the thickener (f) is hindered and sufficient stirring is not performed, and the particle size of the resin increases, so that the particle size distribution also widens.

The amount of the nitrogen-containing compound (g) to be added is 30 to 5 with respect to the vinyl chloride monomer present at that time.
00 ppm, preferably 100 to 400 ppm. If the addition amount is less than 30 ppm, the polymerization cannot be sufficiently suppressed in the aqueous medium, so that the bulk specific gravity is not improved and the effect of preventing scale adhesion becomes insufficient. In addition, the addition amount is 500
When the content exceeds ppm, polymerization can be suppressed to some extent in the aqueous medium and the bulk specific gravity is improved to some extent, but the stability of the oil droplets at the interface with the aqueous medium is not sufficient, and the number of particles having a large particle size increases.

As the nitrogen-containing compound (g), for example, ammonium salt, amide, amino group-containing compound, amine, urea group-containing compound and the like are used.

Examples of the above ammonium salts include hydroxylammonium chloride, hydroxylammonium sulfate, ammonium chloride, ammonium bromide, ammonium hydrogensulfide, ammonium pentasulfide, ammonium sulfite monohydrate, ammonium bisulfite, ammonium sulfate, and hydrogen sulfate. Ammonium, ammonium thiosulfate, ammonium peroxodisulfate, ammonium amidosulfate, ammonium selenite, ammonium azide, ammonium phosphinate, ammonium phosphonate, ammonium hydrogen phosphonate, ammonium phosphate trihydrate, diammonium hydrogen phosphate, phosphoric acid Ammonium dihydrogen, ammonium cyanate, ammonium carbonate monohydrate, diammonium hydrogen carbonate, ammonium metaborate water , Ammonium sodium hydrogen phosphate tetrahydrate, ammonium formate, ammonium acetate, ammonium oxalate monohydrate, ammonium hydrogen oxalate monohydrate, ammonium tetrafluoroborate, ammonium carbamate, and the like. May be used alone or in combination of two or more.

Examples of the amide include nitroylamide, m-acetamidophenol, butylamide,
Hexamethylphosphoric acid triamide, formamide oxime, etc., may be used alone or in combination of two or more.

Examples of the amino group-containing compound include aminoguanidine, 4-amino-1,2,4-triazole, 3-aminobutyric acid, 4-aminobutyric acid, p-aminobenzyl alcohol, 2-aminopentanoic acid, Examples thereof include 2-amino-2-methyl-1-propanol and DL-2-aminobutyric acid, which may be used alone or in combination of two or more.

Examples of the above amine include isopentylamine, N-nitrodimethylamine, 3-pyridylamine, 1,4-butanediamine, 1,3-propanediamine, propylamine, 1,5-pentanediamine, pentyl Examples thereof include amines and the like, and these may be used alone or in combination of two or more.

As the urea group-containing compound, for example,
Acetylthiourea, N-acetyl-N'-methylurea, N
-Ethyl urea, N, N'-dimethyl urea, N, N'-diethyl urea, N, N-dimethyl urea, N-methyl thiourea, etc., which may be used alone or in combination of two or more. You may use together.

Examples of the nitrogen-containing compound (g) other than those described above include, for example, nitrosyl fluorosulfate, azetidine,
-Acetylcarbazide, antipyrine, 2-imidazoline, imidazole, ethylhydrazine, β-erythroidin, ethyl carbamate, methyl carbamate, carbonohydrazide, 6-quinolinol, guanidine carbonate, glycosiamidine, glutaronitrile, cyanuric acid Trimethyl, succinamic acid, piperazine, pilocarpine, pyrrolidine, folidenine, 1-methylimidazole, 4-methylpiperidine, morpholine, lycopozine,
Lupine, etc., may be used alone or in combination of two or more.

The nitrogen-containing compound (g) has a molecular weight of 70
To 150 are preferable. Examples of such a nitrogen-containing compound (g) include hydroxylammonium chloride, ammonium bromide, ammonium sulfite monohydrate, ammonium hydrogen sulfite, ammonium sulfate, ammonium hydrogen sulfate, ammonium thiosulfate, and the like. Ammonium amidosulfate, ammonium phosphinate, ammonium phosphonate, ammonium hydrogen phosphonate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium carbonate monohydrate, ammonium metaborate hydrate,
Examples thereof include ammonium ammonium hydrogen phosphate tetrahydrate, ammonium acetate, ammonium oxalate monohydrate, ammonium hydrogen oxalate monohydrate, ammonium salts such as ammonium tetrafluoroborate and ammonium carbamate.

Preferred nitrogen-containing compounds (g) other than the above ammonium salts include, for example, butylamide, aminoguanidine, 4-amino-1,2,4-triazole, 3-aminobutyric acid, 4-aminobutyric acid, p-aminobutyric acid and p-aminobutyric acid. -Aminobenzyl alcohol, 2-aminopentanoic acid, 2-amino-2-methyl-1-propanol, DL-2-aminobutyric acid, isopentylamine, N-nitrodimethylamine, 3-pyridylamine, 1,4-butane Diamine,
1,3-propanediamine, 1,5-pentanediamine, pentylamine, acetylthiourea, N-acetyl-N'-methylurea, N-ethylurea, N, N'-dimethylurea, N, N'-diethylurea , N, N-dimethylurea,
N-methylthiourea, nitrosyl fluorosulfate, 1-acetylcarbazide, 2-imidazoline, imidazole,
Ethyl hydrazine, ethyl carbamate, methyl carbamate, carbonohydrazide, 6-quinolinol, glycosiamidine, glutaronitrile, succinamic acid,
Piperazine, pyrrolidine, 1-methylimidazole, 4
-Methylpiperidine, morpholine and the like.

Next, the second invention will be described. In the suspension polymerization method of the second invention, similarly to the first invention, when a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator, a partially saponified polyvinyl acetate ( a) and at least one dispersant among the cellulose derivatives (b), at least one emulsifier among the sorbitan higher fatty acid ester (c) and the anionic emulsifier (d), a higher fatty acid (e), and a thickener The polymerization is started by adding the agent (f).

In the suspension polymerization method of the second invention, when the weight ratio of the vinyl chloride monomer / aqueous medium is 0.8 to 0.3, preferably 0.7 to 0.35, the aqueous medium (H) is added. The aqueous medium (h) is preferably deionized water, but is not particularly limited as long as it is an aqueous medium usually used for polymerization.

If the aqueous medium (h) is added when the weight ratio of the vinyl chloride monomer / aqueous medium is less than 0.3, resin particles have already been formed. And the effect of improving the bulk specific gravity is poor even when the aqueous medium (h) is added. When the aqueous medium (h) is added at the time when the above weight ratio exceeds 0.8, the amount of the vinyl chloride monomer in the resin already polymerized in the oil droplets is increased because the amount of the vinyl chloride monomer is too large. The amount of the monomer cannot be reduced, and the bulk specific gravity cannot be improved.

The amount of the aqueous medium (h) to be added is 0.1% by weight with respect to the vinyl chloride monomer 1 present at that time.
05 to 1, preferably 0.3 to 0.9. If the amount of the aqueous medium (h) is less than 0.05, the effect of the addition of the aqueous medium is not sufficient to discharge the unreacted vinyl chloride monomer in the oil droplets. Thus, although the bulk specific gravity is improved, the frequency of coalescence between oil droplets is reduced beyond an appropriate range, and the particle size distribution is widened.

Next, the third invention will be described. In the suspension polymerization method of the third invention, similarly to the first invention, when a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator, a partially saponified polyvinyl acetate ( a) and at least one dispersant among the cellulose derivatives (b), at least one emulsifier among the sorbitan higher fatty acid ester (c) and the anionic emulsifier (d), a higher fatty acid (e), and a thickener The polymerization is started by adding the agent (f).

In the suspension polymerization method of the third invention, for the same reason as in the second invention, the weight ratio of vinyl chloride monomer / aqueous medium is 0.8 to 0.3, preferably 0.7 to 0. .3
At point 5, an aqueous medium (i) further containing an antifoam is added. The amount of the aqueous medium (i) to be added is 0.05 to 1 in weight ratio to the vinyl chloride monomer 1 present at that time, for the same reason as in the second invention, and is preferably 0.3 to 0.9.

Examples of the antifoaming agent contained in the aqueous medium (i) include known antifoaming agents disclosed in JP-B-57-17003, JP-A-2-180908, and JP-A-3-212409. Those which can be used include, for example, silicone oils such as polysiloxane, dimethylpolysiloxane and diphenylpolysiloxane; polyvinyl alcohol having a low saponification degree (particularly 20 to 60 mol%); sodium hydroxide, ammonia and the like. And the like. Among the above antifoaming agents, the use of dimethylpolysiloxane commercially available as an antifoaming agent (especially, one having a siloxane having a Si bond of 5 to 40 is preferable, more preferably one having an Si bond of 8 to 20) is preferable. .

When the amount of the defoaming agent is small, the effect of the defoaming agent is poor and the bulk specific gravity cannot be improved, and when the amount is large, the thermal stability of the resin is lowered or the particle size distribution is widened. 5 to 1,0 relative to the aqueous medium present at the time
00 ppm is preferable, and more preferably 10 to 200 p
pm.

The aqueous medium is preferably deionized water, but is not particularly limited as long as it is an aqueous medium usually used for polymerization.

Next, the fourth invention will be described. In the suspension polymerization method of the fourth invention, as in the first invention, when the vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator, the reaction system is partially saponified. At least one dispersant of polyvinyl acetate (a) and cellulose derivative (b); at least one emulsifier of sorbitan higher fatty acid ester (c) having an HLB value of 3 to 10 and anionic emulsifier (d) , A higher fatty acid (e) having 8 to 25 carbon atoms and a thickener (f) are added to initiate polymerization.

In the suspension polymerization method of the fourth invention, when the weight ratio of vinyl chloride monomer / aqueous medium is 0.7 to 0.4, preferably 0.6 to 0.45, the viscosity is further increased. An aqueous medium containing the agent (f) is added. When the weight ratio is 0.
If it exceeds 7, the amount of the vinyl chloride monomer itself is too large, so that even if water is added, the amount of the monomer in the resin already polymerized in the oil droplets cannot be reduced, and the bulk specific gravity is improved. Can not expect. In addition, when the weight ratio is less than 0.4, the vinyl chloride monomer itself is small, and since the resin particles formed by the already polymerized resin are mostly completed, the effect of improving the bulk specific gravity by adding water is obtained. It becomes difficult.

The amount of the aqueous medium (j) containing the thickener (f) is 0.1 to 1 by weight, preferably 0 to 1 based on the vinyl chloride monomer 1 present at that time. .2
0.6. When the amount of the aqueous medium (j) added to the vinyl chloride-based monomer is less than 0.1, the effect of adding water to release the unreacted vinyl chloride-based monomer present in the oil droplets is reduced. The effect of improving the bulk specific gravity is poor. Also,
When the amount of the aqueous medium (j) added to the vinyl chloride monomer exceeds 1, the amount of the aqueous medium becomes excessive and the bulk specific gravity is improved, but the coalescence frequency between the oil droplets exceeds the appropriate range. Because of the decrease, the particle size distribution is widened.

The aqueous medium is preferably deionized water, but is not particularly limited as long as it is an aqueous medium usually used for polymerization. As the thickener (f), the same thickener as in the third invention is used.

Next, the fifth invention will be described. In the suspension polymerization method of the fifth invention, as in the first invention, when the vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator, the reaction system is partially saponified. At least one dispersant of polyvinyl acetate (a) and cellulose derivative (b); at least one emulsifier of sorbitan higher fatty acid ester (c) having an HLB value of 3 to 10 and anionic emulsifier (d) , A higher fatty acid (e) having 8 to 25 carbon atoms and a thickener (f) are added to initiate polymerization.

In the suspension polymerization method of the fifth invention, when the weight ratio of the vinyl chloride monomer / aqueous medium is 0.8 to 0.3, preferably 0.7 to 0.35, An aqueous medium (j) containing a vinyl monomer and a thickener (f) is added.

When the weight ratio of the vinyl chloride monomer is 0.8
If it exceeds, the vinyl chloride monomer itself is too much,
Almost no progress has been made in the formation of the resin particle diameter by the already polymerized resin, and an improvement in the bulk specific gravity cannot be expected. When the weight ratio is less than 0.3, the amount of the vinyl chloride-based monomer itself is small, and the formation of the resin particles by the already polymerized resin is mostly completed. In addition, the production efficiency is reduced due to a large delay in the polymerization time.

The amount of the vinyl chloride monomer added is based on the amount of the vinyl chloride monomer 1 present in the polymerization tank at that time.
The weight ratio is limited to 0.05 to 1, preferably 0.3 to 0.9 by weight.

If the weight ratio of the vinyl chloride monomer exceeds 1, the amount of the vinyl chloride monomer itself is too large, so that the bulk specific gravity can be improved, but the viscosity of the polymerization system is significantly increased. The polymerization reaction becomes unstable. On the other hand, if the weight ratio is less than 0.05, it is not possible to improve the production amount or the bulk specific gravity.

Further, the amount of the vinyl chloride-based monomer to be added is preferably not so much as to exceed the initially charged amount in view of the internal volume of the polymerization tank. Even if safety considerations should be taken into account,
There is no particular limitation on the purpose of the present application.

If the weight ratio of the aqueous medium (j) containing the thickener (f) exceeds 0.8, the formation of the resin particle size hardly progresses. Drops are formed and bulk specific gravity cannot be improved. If the weight ratio is less than 0.3, the vinyl chloride monomer itself is small,
Since the formation of the resin particles by the already polymerized resin is mostly completed, the effect of improving the bulk specific gravity is poor.

The amount of the aqueous medium (j) to be added is limited to 0.05 to 1 by weight, preferably 0 to 0, in weight ratio with respect to the vinyl chloride monomer 1 present in the polymerization tank at that time. .
3 to 0.9. When the weight ratio of the aqueous medium (j) exceeds 1, the amount of the aqueous medium (j) itself is too large, so that the coalescence frequency between the oil droplets is reduced beyond an appropriate range, and the particle size distribution is widened. On the other hand, if the weight ratio is less than 0.05, the effects of preventing the resin from "floating" near the liquid surface and preventing scale will not be obtained.

When the amount of the thickener (f) added to the aqueous medium (j) is too small, the effect of the thickener is not exhibited, so that the bulk specific gravity is not improved. Since the distribution is wide, the amount of the aqueous medium existing in the polymerization tank at the completion of addition of all the aqueous medium is 10 to 1,000.
0 ppm is preferable, and more preferably, 20 to 500 pp.
m.

Further, the amount of the aqueous medium (j) to be added is preferably not so much as to exceed the initial charge in view of the internal volume of the polymerization tank. Although it should be considered in terms of aspects, it is not particularly limited for the purposes of the present application.

The aqueous medium is preferably deionized water, but is not particularly limited as long as it is an aqueous medium usually used for polymerization. As the thickener (f), the same thickener as in the third invention is used.

In the fifth aspect of the present invention, the batch production is improved by adding a vinyl chloride monomer. Further, by adding an aqueous medium containing a thickener, the viscosity of the polymerization system is increased and the stirring action is improved. By the improvement of the stirring action, the "floating phenomenon" of the resin near the liquid level in the polymerization process is suppressed, and the scale adhesion is suppressed.

Examples of the vinyl chloride monomer used in the present invention include a vinyl chloride monomer and a mixture of a vinyl chloride monomer and a monomer other than vinyl chloride. Examples of the monomer other than vinyl chloride include those which can be copolymerized with a vinyl chloride monomer, and include, for example, alkyl vinyl esters such as vinyl acetate; α-monoolefins such as ethylene and propylene; methyl ( In addition to alkyl (meth) acrylates such as meth) acrylate, ethyl (meth) acrylate, and octyl acrylate, alkyl vinyl ether, maleimide, vinylidene chloride, styrene, and the like may be used, and these may be used alone or in combination of two or more. May be used in combination. In the mixture of the vinyl chloride monomer and a monomer other than vinyl chloride, the proportion of the vinyl chloride monomer is preferably 50% by weight or more.

The polymerization initiator used in the present invention includes:
Known radical polymerization initiators generally used for the polymerization of vinyl chloride resins can be used. For example, t-butyl peroxy neodecanoate, t-hexyl peroxy pivalate, α-cumyl peroxy neo Perester compounds such as decanoate, t-hexyl neohexanoate, 2,4,4-trimethylpentyl-2-peroxy-2-neodecanoate; diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate; Percarbonate compounds such as di-2-ethoxyethylperoxydicarbonate and dimethoxyisopropylperoxydicarbonate; decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, cumene hydroperoxide, cyclohexanone peroxide 2,4-dichlorobenzoyl peroxide, p- menthane hydroperoxide, 3,5,
Peroxide compounds such as 5-trimethylhexanoyl peroxide and isobutyl peroxide; α, α′-azobisisobutyronitrile, α, α′-azobis (dimethylvaleronitrile), α, α′-azobis (4-methoxy −
2,4-dimethylvaleronitrile) and the like, and these may be used alone or in combination of two or more.

The structure of the polymerization vessel (pressure-resistant autoclave) used in the suspension polymerization method of the present invention is not particularly limited, and a known structure conventionally used for polymerization of vinyl chloride is used. Further, the stirring blade may be a general-purpose one such as a faudler blade, a paddle blade, a turbine blade, a fan turbine blade, a bull margin blade, or the like, and the combination with a baffle plate is not particularly limited.

In the above polymerization reaction, a method of adding deionized water, a dispersant, an emulsifier, a higher fatty acid, a thickener, a nitrogen-containing compound, a vinyl chloride monomer and the like is carried out by a conventionally known method. Depending on the conditions, a polymerization regulator, a chain transfer agent, an antistatic agent, a crosslinking agent, a stabilizer, a filler, a scale inhibitor, a pH regulator and the like may be added. The addition method may be any of batch addition, intermittent addition, and continuous addition.

[0088]

Embodiments of the present invention will be described below. (Example 1) 45 kg of deionized water was put into a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and further partially saponified polyvinyl acetate (saponification degree: 72 mol%, average polymerization) with respect to a vinyl chloride monomer. Degree 700) 500 ppm,
Sorbitan monolaurate (HLB = 8.6) 1600
ppm, lauric acid 1500 ppm, polyethylene oxide (average molecular weight = 4.3 million to 4.8 million, η = 12c
ps) 100 ppm, and 500 ppm of t-butyl peroxy neodecanoate. Next, after the inside of the polymerization vessel was degassed to 40 mmHg, 45 kg of a vinyl chloride monomer was charged and stirring was started. Thereafter, the temperature inside the polymerization vessel was raised to 57 ° C. to start polymerization, and this temperature was maintained until the polymerization reaction was completed. After the polymerization temperature reaches a constant temperature, when about 5 kg of vinyl chloride monomer is consumed (vinyl chloride monomer / aqueous medium = about 0.5), 230 ppm of ammonium amidosulfate (molecular weight 114) is added, and the polymerization is started. Continued. The reaction was terminated when the polymerization conversion reached 90%,
After recovering the unreacted monomer in the polymerization vessel, the polymer was taken out in a slurry state, and dehydrated and dried to obtain a vinyl chloride resin.

(Examples 2 to 4, Comparative Examples 1 to 6) Except that the dispersant, emulsifier, higher fatty acid, thickener and nitrogen-containing compound in the amounts shown in Tables 1 and 2 were added. 1
In the same manner as in the above, a vinyl chloride resin was obtained.

[0090]

[Table 1]

[0091]

[Table 2]

The vinyl chloride resins obtained in the above Examples and Comparative Examples were subjected to the following performance evaluations.
And 2. (1) Porosity Using a plasticizer absorbency as an index of porosity, 5 g of a vinyl chloride resin is weighed into a centrifuge tube (grain size: G2) with a glass filter, and an excess amount of DOP (dioctyl phthalate) relative to the resin is measured. About 20 cc of a plasticizer was added and mixed well. Next, excess DOP was separated by a centrifugal separator (“H-200N” manufactured by Domestic Centrifuge Co., Ltd., rotation number: 6000 rpm), and the DOP absorption amount (phr) relative to 100 parts by weight of the resin was determined.

(2) Particle size distribution According to JIS Z8801, 60, 100 and 15
The mixture was sieved using three types of sieves of 0 mesh and the passing amount (% by weight) was calculated. When the weight% was concentrated on one mesh, the particle size distribution was determined to be sharp, and when the weight% was dispersed in each mesh, the particle size distribution was determined to be poor.

(3) Bulk specific gravity Measured according to JIS Z6721.

(4) Workability The gelation time (min) and the maximum torque (mk) during the gelation of the vinyl chloride resin composition were determined under the following conditions using "Haakereo Code 90" manufactured by Toyo Seiki Co., Ltd.
g · min) was measured. After charging 60 g of the above resin composition into the Haakereo cord 90, the temperature was raised at a rate of 5 ° C./min from 120 ° C. at a rotation speed of 50 rpm to 200 ° C.
The measurement was performed until. The vinyl chloride resin composition was prepared by using a montanic acid ester ("WAX O" manufactured by Hoechst) as a lubricant with respect to 100 parts by weight of the vinyl chloride resin.
P)) 0.5 parts by weight and 2 parts by weight of dibutyltin mercapto ("JF-10B" manufactured by Sankyokisei Co., Ltd.) as a stabilizer were added, and the mixture was heated to 120 ° C with a super mixer (manufactured by Mitsui Miike) and mixed. After that, the one cooled to 40 ° C. was used.

(5) Surface Condition The vinyl chloride resin particles were photographed with a scanning electron microscope (“FE-SEM S-4200” manufactured by Hitachi, Ltd.) at an acceleration voltage of 2 kV and a magnification of 130 times, and the contours and skin portions of the particles were used. (The part where the skin remains), the skin part, and the part where the skin does not exist (the part where the primary particles are exposed, hereinafter referred to as a skin-free part) were copied on a tracing paper (or an OHP sheet). Next, the tracing paper (or OHP sheet) is introduced into an image analyzer (“PIAS-III” manufactured by Pierce) to perform image analysis, and the total area of the particles and the remaining area of the skin-free portion are calculated by the following equation. The remaining skin ratio was determined. The average value of the measured values of 50 particles is shown in the table. Skin-free ratio (%) = (skin-free area / total particle area) x 100

[0097]

[Table 3]

[0098]

[Table 4]

(Example 6) 45 kg of deionized water was put into a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and a partially saponified polyvinyl acetate (with a saponification degree of 72 mol%) was added to the vinyl chloride monomer. , Average degree of polymerization 700)
500 ppm, sorbitan monolaurate (HLB =
8.6) 1600 ppm, lauric acid 1500 ppm,
Polyethylene oxide (average molecular weight = 4.3 million to 48
100,000, η = 12 cps) 100 ppm, and t-
500 ppm of butyl peroxy neodecanoate was charged. Next, after the inside of the polymerization vessel was degassed to 40 mmHg, 45 kg of a vinyl chloride monomer was charged and stirring was started. Thereafter, the temperature inside the polymerization vessel was raised to 57 ° C. to start polymerization, and this temperature was maintained until the polymerization reaction was completed. After the polymerization temperature reaches a constant temperature, when about 19 kg of vinyl chloride monomer is consumed (vinyl chloride monomer / aqueous medium = about 0.6), 10 kg of deionized water (based on the vinyl chloride monomer) (Weight ratio of about 0.4) was added in 10 minutes, and the polymerization was continued. When the polymerization conversion reached 90%, the reaction was terminated. After the unreacted monomer in the polymerization vessel was recovered, the polymer was taken out in the form of slurry, and dehydrated and dried to obtain a vinyl chloride resin.

(Examples 7 to 9, Comparative Examples 7 to 11) Except for adding the dispersants, emulsifiers, higher fatty acids, thickeners and nitrogen-containing compounds in the amounts shown in Tables 5 and 6, In the same manner as in 6, a vinyl chloride resin was obtained.

[0101]

[Table 5]

[0102]

[Table 6]

With respect to the vinyl chloride resins obtained in Examples 6 to 9 and Comparative Examples 7 to 11, the same as in Example 1,
Performance evaluations (1) to (5) were performed, and the results are shown in Table 7.
And 8.

[0104]

[Table 7]

[0105]

[Table 8]

Example 10 45 kg of deionized water was charged into a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and a partially saponified polyvinyl acetate (a saponification degree of 72 mol%) was added to the vinyl chloride monomer. , Average degree of polymerization 700)
500 ppm, sorbitan monolaurate (HLB =
8.6) 1600 ppm, lauric acid 1500 ppm,
Polyethylene oxide (average molecular weight = 4.3 million to 48
100,000, η = 12 cps) 100 ppm, and t-
500 ppm of butyl peroxy neodecanoate was charged. Next, after the inside of the polymerization vessel was degassed to 40 mmHg, 45 kg of a vinyl chloride monomer was charged and stirring was started. Thereafter, the temperature inside the polymerization vessel was raised to 57 ° C. to start polymerization, and this temperature was maintained until the polymerization reaction was completed. After the polymerization temperature reaches a constant temperature, when about 19 kg of vinyl chloride monomer is consumed (vinyl chloride monomer / aqueous medium = about 0.6), 10 kg of deionized water containing an antifoaming agent (vinyl chloride) is used. A total of about 0.4) (weight ratio to monomer) was added over 20 minutes, and polymerization was continued. When the polymerization conversion reached 90%, the reaction was terminated. After the unreacted monomer in the polymerization vessel was recovered, the polymer was taken out in the form of slurry, and dehydrated and dried to obtain a vinyl chloride resin. The addition amount of the defoaming agent was calculated and added in advance so that the total amount of the aqueous medium present in the polymerization vessel at the time of completion of the addition of water was 50 ppm. As the defoaming agent, a commercially available polysiloxane having a Si main chain of about 15 to 20 was used as a mixture.

(Examples 11 to 13, Comparative Examples 12 to 14)
Except for adding the dispersant, emulsifier, higher fatty acid, thickener and nitrogen-containing compound in the amounts shown in Tables 9 and 10,
A vinyl chloride resin was obtained in the same manner as in Example 10.

[0108]

[Table 9]

[0109]

[Table 10]

Examples 10 to 13 and Comparative Examples 12 to 1
With respect to the vinyl chloride resin obtained in No. 4, performance evaluations (1) to (5) were performed as in Example 1, and the results are shown in Table 11.

[0111]

[Table 11]

(Example 14) 45 kg of deionized water was put into a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and a partially saponified polyvinyl acetate (a saponification degree of 72 mol%) was added to the vinyl chloride monomer. , Average degree of polymerization 700)
500 ppm, sorbitan monolaurate (HLB =
8.6) 1600 ppm, lauric acid 1500 ppm,
Polyethylene oxide (average molecular weight = 4.3 million to 48
100,000, η = 12 cps) 100 ppm, and t-
500 ppm of butyl peroxy neodecanoate was charged. Next, after the inside of the polymerization vessel was degassed to 40 mmHg, 45 kg of a vinyl chloride monomer was charged and stirring was started. Thereafter, the temperature inside the polymerization vessel was raised to 57 ° C. to start polymerization, and this temperature was maintained until the polymerization reaction was completed. After the polymerization temperature reached a constant temperature, when about 25 kg of vinyl chloride monomer was consumed (vinyl chloride monomer / aqueous medium = 0.55),
Deionized water containing a thickener (the same polyethylene oxide as above) was added in a total amount of 8 kg (weight ratio of about 0.4 with respect to the vinyl chloride monomer) in 40 minutes, and polymerization was continued. When the polymerization conversion reached 90%, the reaction was terminated. After the unreacted monomer in the polymerization vessel was recovered, the polymer was taken out in the form of slurry, and dehydrated and dried to obtain a vinyl chloride resin. still,
The amount of the thickener added later was calculated so as to be 300 ppm with respect to the total amount of the aqueous medium in the polymerization vessel at the completion of the water addition, and the thickener added beforehand to the aqueous medium was used.

(Examples 15 to 17, Comparative Examples 15 to 19)
A vinyl chloride-based resin was obtained in the same manner as in Example 14, except that the aqueous medium containing the dispersant, the emulsifier, the higher fatty acid, the thickener and the thickener in the amounts shown in Tables 12 and 13 was added. Was. The amount of the thickener added later was calculated to be 300 ppm for polyethylene oxide and 200 ppm for polyacrylamide, based on the total amount of the aqueous medium in the polymerization vessel at the completion of water addition. What was previously added to the aqueous medium was used.

[0114]

[Table 12]

[0115]

[Table 13]

Examples 14 to 17 and Comparative Examples 15 to 1
With respect to the vinyl chloride resin obtained in No. 9, performance evaluations (1) to (5) were performed in the same manner as in Example 1, and the results are shown in Table 14.

[0117]

[Table 14]

Example 18 45 kg of deionized water was charged into a polymerization vessel (pressure-resistant autoclave) having an internal volume of 100 liters, and a partially saponified polyvinyl acetate (degree of saponification: 72 mol%) was added to the vinyl chloride monomer. , Average degree of polymerization 700)
500 ppm, sorbitan monolaurate (HLB =
8.6) 1600 ppm, lauric acid 1500 ppm,
Polyethylene oxide (average molecular weight = 4.3 million to 48
100,000, η = 12 cps) 100 ppm, and t-
500 ppm of butyl peroxy neodecanoate was charged. Next, after the inside of the polymerization vessel was degassed to 40 mmHg, 45 kg of a vinyl chloride monomer was charged and stirring was started. Thereafter, the temperature inside the polymerization vessel was raised to 57 ° C. to start polymerization, and this temperature was maintained until the polymerization reaction was completed. After the polymerization temperature reaches a constant temperature, when about 19 kg of vinyl chloride monomer is consumed (vinyl chloride monomer / aqueous medium = about 0.6), 10 kg of vinyl chloride monomer (vinyl chloride in the polymerization vessel) 20 kg of deionized water containing the thickener (polyethylene oxide similar to the above) and 10 wt. The whole amount was added in one minute, and the polymerization was continued. When the polymerization conversion reached 90%, the reaction was terminated. After the unreacted monomer in the polymerization vessel was recovered, the polymer was taken out in the form of slurry, and dehydrated and dried to obtain a vinyl chloride resin. The amount of the thickener added later was calculated so as to be 300 ppm with respect to the total amount of the aqueous medium in the polymerization vessel at the completion of the addition of water, and the one added in advance to the aqueous medium was used.

(Examples 19 to 26, Comparative Examples 20 to 28)
A vinyl chloride-based resin was obtained in the same manner as in Example 18 except that the aqueous medium containing the dispersant, the emulsifier, the higher fatty acid, the thickener and the thickener in the amounts shown in Tables 15 to 18 was added. Was. The amount of the thickener added later was calculated to be 300 ppm for polyethylene oxide and 200 ppm for polyacrylamide, based on the total amount of the aqueous medium in the polymerization vessel at the completion of water addition. What was previously added to the aqueous medium was used.

[0120]

[Table 15]

[0121]

[Table 16]

[0122]

[Table 17]

[0123]

[Table 18]

Examples 18 to 26 and Comparative Examples 20 to 2
With respect to the vinyl chloride resin obtained in No. 8, performance evaluations (1) to (5) were performed in the same manner as in Example 1, and the results are shown in Tables 19 and 20.

[0125]

[Table 19]

[0126]

[Table 20]

[0127]

The method of the present invention for suspending and polymerizing a vinyl chloride monomer has the above-mentioned constitution. In the production process, polymer scale adheres little to the inner wall of the polymerization vessel, and the obtained vinyl chloride resin is sharp. It has an excellent particle size distribution and a high bulk specific gravity, has almost no skin portion in the particles, and has excellent moldability.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuki Goto 4560 Kaiseicho, Shinnanyo-shi, Yamaguchi Prefecture Sekisui Chemical Co., Ltd.

Claims (5)

[Claims] When a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator,
At least one dispersant of partially saponified polyvinyl acetate (a) and cellulosic derivative (b) having an HLB value of 3
At least one of sorbitan higher fatty acid ester (c) and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and 0.1% by weight aqueous solution at normal temperature and pressure. After adding a thickener (f) having a Brookfield viscosity of 10 to 200 cps to initiate polymerization, when the weight ratio of vinyl chloride monomer / aqueous medium is 1.1 to 0.3, A water-soluble nitrogen-containing compound (g) having a molecular weight of 50 to 300 and having at least one nitrogen atom is added, and the amount of the nitrogen-containing compound (g) added to the vinyl chloride monomer present at that time 3 for
A method for suspension polymerization of a vinyl chloride-based monomer, which is from 0 to 500 ppm. 2. When a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator,
At least one dispersant of partially saponified polyvinyl acetate (a) and cellulosic derivative (b) having an HLB value of 3
At least one of sorbitan higher fatty acid ester (c) and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and 0.1% by weight aqueous solution at normal temperature and pressure. After adding a thickener (f) having a Brookfield viscosity of 10 to 200 cps to initiate polymerization, when the weight ratio of vinyl chloride monomer / aqueous medium is 0.8 to 0.3, An aqueous medium (h) is added, and the amount of the aqueous medium (h) added is 0.05 to 1 in a weight ratio to the vinyl chloride monomer 1 present at that time.
A suspension polymerization method for a vinyl chloride monomer. 3. A suspension system of a vinyl chloride monomer in an aqueous medium in the presence of an oil-soluble polymerization initiator,
At least one dispersant of partially saponified polyvinyl acetate (a) and cellulosic derivative (b) having an HLB value of 3
At least one of sorbitan higher fatty acid ester (c) and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and 0.1% by weight aqueous solution at normal temperature and pressure. After adding a thickener (f) having a Brookfield viscosity of 10 to 200 cps to initiate polymerization, when the weight ratio of vinyl chloride monomer / aqueous medium is 0.8 to 0.3, An aqueous medium (i) containing an antifoaming agent is added, and the amount of the aqueous medium (i) added is 0.05 to 1 in a weight ratio to the vinyl chloride monomer 1 present at that time. A suspension polymerization method for a vinyl chloride monomer. 4. When suspension polymerization of a vinyl chloride monomer in an aqueous medium in the presence of an oil-soluble polymerization initiator,
At least one dispersant of partially saponified polyvinyl acetate (a) and cellulosic derivative (b) having an HLB value of 3
At least one of sorbitan higher fatty acid ester (c) and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and 0.1% by weight aqueous solution at normal temperature and pressure. After adding a thickener (f) having a Brookfield viscosity of 10 to 200 cps to initiate polymerization, when the weight ratio of the vinyl chloride monomer / aqueous medium is 0.7 to 0.4, The thickener (f)
Is added, and the aqueous medium (j) is added.
Of the vinyl chloride monomer 1 present at that time
A suspension polymerization method of a vinyl chloride monomer, wherein the weight ratio is 0.1 to 1. 5. When a vinyl chloride monomer is subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization initiator,
At least one dispersant of partially saponified polyvinyl acetate (a) and cellulosic derivative (b) having an HLB value of 3
At least one of sorbitan higher fatty acid ester (c) and anionic emulsifier (d), higher fatty acid (e) having 8 to 25 carbon atoms, and 0.1% by weight aqueous solution at normal temperature and pressure. After adding a thickener (f) having a Brookfield viscosity of 10 to 200 cps to initiate polymerization, when the weight ratio of vinyl chloride monomer / aqueous medium is 0.8 to 0.3, The vinyl chloride monomer and the aqueous medium (j) containing the thickener (f) are added, and the amounts of the vinyl chloride monomer and the aqueous medium (j) are present at that time. A suspension polymerization method for a vinyl chloride-based monomer, wherein the weight ratio of the vinyl chloride-based monomer to the vinyl chloride-based monomer 1 is 0.05 to 1.