JPH0770210A - Method for producing vinyl chloride polymer - Google Patents

Abstract

PURPOSE:To produce uniform polymer particles having excellent powder characteristics by subjecting a vinyl chloride-based monomer to suspension polymerization using a prescribed dispersion stabilizer and an initiator in a fixed water/monomer ratio. CONSTITUTION:In subjecting a vinyl chloride-based monomer to suspension polymerization in the presence of a dispersion stabilizer, an oil-soluble initiator, an oily initiator which comprises constituent components of formula I and formula II (R<1> is hydrogen, a lower alkyl or nitrile; R<2> is hydrogen or a lower alkyl; R<3> is hydrogen, a halogen, an alkyl or phenyl; X is O, etc.; Y is NH, etc.; (p) and (r) are 0-6; (q) is 0-l; (n) is 0-500), links the components through ester bond, amide bond and urethane bond and has 2,000-300,000 weight-average molecular weight (Mw) is used as the oily initiator. The ratio of water/the vinyl chloride-based monomer is 1.5-2.5. A partially saponified polyvinyl alcohol having 1,000-5,000 degree of polymerization and 70-95% degree of saponification is used as the dispersion stabilizer and the amount of the saponified polyvinyl alcohol used is 0.05-0.5 pt.wt. based on the vinyl chloride monomer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a silicone-vinyl chloride block copolymer having excellent powder characteristics.

[0002]

2. Description of the Related Art Polyvinyl chloride resins are inexpensive and have excellent chemical and physical properties, so that they are produced in large quantities and used in a wide range of fields. In addition, recently, in order to impart weather resistance, abrasion resistance, processability, etc. to polyvinyl chloride resins, polymer initiators made of polysiloxane amides containing azo groups are used to polymerize with vinyl chloride monomers. The obtained silicone-vinyl chloride block copolymer has been proposed (see, for example, JP-A-61-2522).
30 publication). However, when the vinyl chloride monomer is polymerized using the above-mentioned polymer initiator, the obtained polymer is coarsened or blocking occurs in the polymerization process, and a uniform particle of silicone-vinyl chloride block copolymer is obtained. It was difficult to obtain a polymer.

[0003]

An object of the present invention is to carry out suspension polymerization of vinyl chloride type monomers using a polymer initiator,
An object of the present invention is to provide a method for producing a silicone-vinyl chloride block copolymer having excellent powder characteristics.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above-mentioned problems, the present inventors have found that when a silicone-vinyl chloride block copolymer is produced using a polymer initiator, It was found that silicone-vinyl chloride copolymer particles having excellent powder characteristics can be obtained by setting the water / monomer ratio of the above and using a specific dispersion stabilizer.
The present invention has been reached.

That is, the present invention uses a vinyl chloride monomer as water,
In a method for producing a vinyl chloride-based polymer in which suspension polymerization is carried out in the presence of a dispersion stabilizer and an oil-soluble initiator, the oil-soluble initiator contains at least constituent components represented by the following general formulas (1) and (2), Each component is bonded through an ester bond, an amide bond or a urethane bond, and Mw is 2
000 to 300000 is used as the polymer stabilizer, the weight ratio of water and vinyl chloride monomer is set to water / vinyl chloride monomer = 1.5 to 2.5, and the degree of polymerization is 1000 as a dispersion stabilizer. Vinyl chloride characterized by using 0.05 to 0.5% by weight of partially saponified polyvinyl alcohol (hereinafter referred to as PVA) having a saponification degree of 5,000 to 70% and a saponification degree of 70 to 95%. It is a method for producing a polymer.

[0006]

[Chemical 5]

[0007]

[Chemical 6]

(In the above formula, each R ¹ may be the same or different and represents a hydrogen atom, a lower alkyl group or a nitrile group, and each R ² may be the same or different, a hydrogen atom or a lower alkyl group. And each R ³ may be the same or different and represents a hydrogen atom, a halogen atom-substituted or unsubstituted alkyl group or a phenyl group, and X
Is

[0009]

[Chemical 7]

And Y is

[0011]

[Chemical 8]

And p and r, which may be the same or different, each represents an integer of 0 to 6, q represents 0 or 1, and n represents an integer of 0 to 500) Hereinafter, the present invention will be described in detail. Explained.

In the suspension polymerization of the present invention, the weight ratio of water and vinyl chloride monomer is water / vinyl chloride monomer =
It is 1.5 to 2.5. If this ratio is less than 1.5, the vinyl chloride-based monomer in which the polymer initiator used is dissolved cannot be uniformly dispersed in water, and as a result, blocking occurs during polymerization and stirring becomes impossible. On the other hand, when it exceeds 2.5, the obtained particles of the vinyl chloride polymer are pulverized to make it difficult to dehydrate or reduce the productivity.

In the present invention, PVA is used as the dispersion stabilizer, and the degree of polymerization of this PVA is 1000 to 500.
0 is good. When PVA having a degree of polymerization of less than 1000 is used, the resulting vinyl chloride polymer has a large particle size and a wide particle size distribution. In addition, the reproducibility of the blocking rate of the obtained polymer may be lost, and there may be variations among particles. On the other hand, when PVA having a degree of polymerization of more than 5,000 is used, PVA is easily dissolved in the monomer, and the protective colloid property is lowered in the water dispersion system. Further, the saponification degree of PVA used is in the range of 70 to 95%, and when the saponification degree is out of this range, the obtained vinyl chloride polymer particles become coarse, or uniform polymer particles are formed. I can't get it.

The dispersion stabilizer may be used in combination with other dispersion stabilizers in addition to the above PVA. Examples of the other dispersion stabilizers include PVA other than the above, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester. , Gelatin, methyl cellulose, high-molecular dispersion stabilizers such as ethyl cellulose, polyoxyethylene fatty acid esters, polyoxyethylene aromatic esters, polyoxyethylene aliphatic and aromatic ethers, polyoxyethylene sorbitan fatty acid esters, Nonionic surfactants such as polyoxyethylene sorbitol fatty acid ester, block copolymers of polyoxyethylene and polyoxypropylene, sodium alkylsulfate, sodium alkylbenzenesulfonate, sodium dioctylsulfosuccinate Anionic surface active agent is used for.

The amount of the dispersion stabilizer used in the present invention is 0.05 to 0.05 with respect to the vinyl chloride monomer used.
It is in the range of 0.5% by weight, and the amount of the dispersion stabilizer is 0.05.
If less than 0.5% by weight, the vinyl chloride polymer cannot be obtained as a powder, and if more than 0.5% by weight, the yield is reduced due to foaming at the time of monomer recovery, or the dispersion stabilizer is added to the vinyl chloride polymer. It remains and deteriorates the physical properties. Furthermore, when the vinyl chloride polymer of the present invention is used for applications such as a film, the amount of the dispersion stabilizer used is preferably as small as possible in order to improve the transparency of the film, and is preferably in the range of 0.05 to 0.25% by weight. Preference is given to using.

The polymer initiator used as the oil-soluble initiator in the present invention is a compound having a unit in which the constitutional unit represented by the general formula (1) and the constitutional unit represented by the general formula (2) are bonded. As such a compound, for example, a polycondensate of azobiscarboxylic acid and silicone having amino groups at both ends, a polycondensate of azobiscarboxylic acid and silicone having hydroxyl groups at both ends, and azobis alcohol Examples thereof include polycondensates of silicones having carboxylic acid groups at both ends, or azobis alcohols and polycondensates of silicones having hydroxyl groups at both ends and dicarboxylic acids.

Examples of the azobiscarboxylic acid include azobiscyanopropanoic acid, azobiscyanobutanoic acid, azobiscyanopentanoic acid, azobiscyanohexanoic acid and azobiscyanoheptanoic acid. Examples of alcohols include azobiscyanoethanol, azobiscyanopropanol, azobiscyanobutanol, and azobiscyanopentanol, and examples of dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, and pimeline. Examples thereof include aliphatic dicarboxylic acids such as acid, suberic acid, azelaic acid and sebacic acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid.

The method for synthesizing the above-mentioned polymer initiator is, for example, a method in which the carboxylic acid group of the azo compound, silicone compound or dicarboxylic acid is converted into an acid halide and then reacted with a hydroxyl group or an amino group, or a carboxylic acid group and a hydroxyl group or an amino group. Examples thereof include a method of reacting the group with a condensing agent such as tosyl chloride, carbonyldiimidazole, and methylchloropyridinium iodide.

The polymeric initiator used in the present invention is
The repeating unit of silicone is preferably 1 or more and 500 or less. When the repeating unit exceeds 500, the solution viscosity becomes high when dissolved in a vinyl chloride-based monomer, which makes it difficult to disperse in water, and uniform vinyl chloride-based polymer particles may not be obtained. On the other hand, when the number of repeating units is less than 1, the polymerization stability is good, but the blocking rate is lowered, and improvement in the properties of the vinyl chloride polymer cannot be expected.

The molecular weight of the polymer initiator can be controlled by the charging ratio of the raw materials, and those having a polystyrene-equivalent weight average molecular weight of 2000 to 300,000 by gel permeation chromatography (GPC) are used. If it does not reach 2000, the blocking rate will decrease and
When it exceeds 0000, the viscosity of the solution when it is dissolved in the monomer becomes high, so that it becomes difficult to disperse it in water and uniform polymer particles cannot be obtained.

The amount of the polymeric initiator used is preferably 0.01 to 20% by weight based on the vinyl chloride monomer used.

The polymerization temperature can be selected according to the usual polymerization temperature of vinyl chloride. In particular, 30-80 degreeC is preferable.

In polymerization, a polymer initiator and another polymerization initiator can be used in combination. Other polymerization initiators include, for example, acyl peroxides such as lauroyl peroxide and benzoyl peroxide; peroxy esters of organic acids such as tertiary butyl peroxypivalate; dioxy carbonates such as diisopropyl peroxydicarbonate; Examples thereof include azo compounds such as azobisdimethylvaleronitrile, acetylcyclohexylsulfonyl peroxide, and the like.

In the present invention, a vinyl chloride type monomer is used. Here, the vinyl chloride-based monomer means a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith, and as the copolymerizable monomer, for example, Ethylene, propylene, butene, pentene-1, butadiene, styrene, α-methylstyrene, acrylonitrile, vinylidene chloride, vinylidene cyanide, alkyl vinyl ethers, dialkyl maleic acids, carboxylic acid vinyl esters, aryl ethers, fumaric acid esters, Examples thereof include N-vinylpyrrolidone, vinylpyridine, vinylsilanes, acrylic acid alkyl esters, and methacrylic acid alkyl esters.

[0026]

The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto. The evaluation methods used in the examples are shown below.

(1) Particle size / particle size distribution: Measured with a particle size analyzer (Microtrac II, manufactured by Nikkiso Co., Ltd.).

(2) Molecular Weight / Molecular Weight Distribution Determined by GPC (HLC-802A manufactured by Tosoh Corporation) in terms of standard polystyrene.

(3) The infrared absorption spectrum (IR) is
It was measured by the KBr tablet method using IR-460 (manufactured by Shimadzu Corporation).

(4) The NMR spectrum is JNM-GX
400 (manufactured by JEOL Ltd.), CDCl ₃ as a solvent
Was measured using.

(5) Blocking rate (B%) = [Si
(%) (NMR measurement value) -hexane extraction amount (wt%)]
/ Si (%) × 100 (6) Silicone content was calculated by NMR.

Reference Example 1 (Synthesis Example of Polymer Initiator) 4,4′-azobis (4-cyanopentanoic acid) 42.
0 g was dispersed in 800 ml of dichloromethane, to which a solution of 53.5 g of 1,1′-carbonyldiimidazole in 200 ml of dichloromethane was added, and the mixture was stirred at room temperature for reaction. After 1 hour, amino-modified polydimethylsiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-161)
C, number average molecular weight 4500) 670 g was added, and the mixture was stirred at room temperature for 7
Stir for a reaction to react.

After the reaction, the reaction solution was washed several times with methanol, and then the solvent was distilled off at room temperature under reduced pressure to give a rubber-like product 63.
0 g (yield 89%) was obtained. The IR and NMR spectra of the product are shown in FIG. 1 and FIG. 2.

[0034]

[Chemical 9]

It was confirmed to be a compound having the repeating unit shown in: The molecular weight of this compound by GPC is Mw = 84000 and Mn = 3 in terms of polystyrene.
It was 4000.

Example 1 In a 3 liter stainless steel autoclave, 46.3 g of the polymer initiator synthesized in Reference Example 1, 1505 g of water and PVA were added.
38.6 g of a 3% aqueous solution of KH-20 (Nippon Gosei Kagaku Co., Ltd., degree of polymerization 2600, degree of saponification 80%).
15% by weight), and after depressurization and nitrogen substitution were repeated several times, 771 g of vinyl chloride was introduced (water / monomer ratio of 2.0). Pre-dissolved at room temperature for 30 minutes. The rotation speed was increased to 1100 rpm and the temperature was raised to 67 ° C. to start polymerization. When the polymerization pressure reached 8 kg / cm ² , cooling was started and the polymerization was stopped. After recovering unreacted monomer,
The polymer slurry was thoroughly washed with water, dehydrated, and then dried under reduced pressure at 60 ° C. for one day to obtain 575 g of vinyl chloride polymer particles (yield 75%). The obtained particles have an average particle size of 165 μm and a bulk specific gravity of 0.5 as shown in Table 1.
It was 5 g / cc.

Example 2 Polymerization was carried out in the same manner as in Example 1 except that PVA having a polymerization degree of 2400 and a saponification degree of 88% was used. As a result, as shown in Table 1, a vinyl chloride polymer powder having an average particle diameter of 180 μm and a bulk specific gravity of 0.58 g / cc was obtained.

Example 3 Polymerization was carried out in the same manner as in Example 1 except that 1813 g of water (water / monomer ratio of 2.4) was used. As a result, Table 1
Mean particle size 143 μm and bulk density 0.60
A vinyl chloride polymer powder having a g / cc was obtained.

Example 4 Polymerization was carried out in the same manner as in Example 1 except that 1123 g of water (water / monomer ratio of 1.5) was used. As a result, Table 1
Mean particle size 210 μm and bulk density 0.55
A vinyl chloride polymer powder having a g / cc was obtained.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that PVA having a polymerization degree of 600 and a saponification degree of 80% was used. As a result, a vinyl chloride polymer powder as shown in Table 1 was obtained, but it was coarsened. The average particle size of this powder is 1
It was 000 μm or more.

Comparative Example 2 PVA was polymerized in the same manner as in Example 1 except that 10 g of a 3% aqueous solution having a polymerization degree of 2600 and a saponification degree of 80% was used (0.04% by weight based on the monomer). Blocking along the way, stirring stopped due to overload.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that the amount of water was adjusted so that the ratio of water to the monomer was 1.2. Therefore, the stirring was stopped.

Comparative Example 4 Using 2235 g of water, 771 g of vinyl chloride and 77 g of a 3% aqueous solution having a polymerization degree of 1700 and a saponification degree of 88% as PVA (0.3% by weight of monomer), polymerization was carried out at 50 ° C. for 48 hours. As a result, the average particle diameter is 45 μm and the bulk density is 0.45.
A vinyl chloride polymer powder having a g / cc was obtained.

[0044]

[Table 1]

[0045]

INDUSTRIAL APPLICABILITY As described above, when suspension polymerization is carried out using a polymer initiator as in the present invention, a specific dispersant and water / water are used.
By selecting the ratio of the monomers, the average particle size of 100-
Uniform particles of about 250 μm can be obtained.

[Brief description of drawings]

FIG. 1 shows an IR spectrum of a polymer initiator obtained in Reference Example 1.

FIG. 2 shows an NMR spectrum of the polymer initiator obtained in Reference Example 1.

Claims (1)

[Claims] 1. A method for producing a vinyl chloride polymer in which a vinyl chloride monomer is suspension-polymerized in the presence of water, a dispersion stabilizer and an oil-soluble initiator, wherein at least the following general formula (1) is used as the oil-soluble initiator. ) And (2) are included,
Using a polymer initiator in which each component is bonded through an ester bond, an amide bond or a urethane bond and having a weight average molecular weight (Mw) of 2000 to 300,000, the weight of water and vinyl chloride monomer charged The ratio of water / vinyl chloride monomer is 1.5 to 2.5, and partially saponified polyvinyl alcohol having a polymerization degree of 1000 to 5000 and a saponification degree of 70 to 95% is used as a dispersion stabilizer. The method for producing a vinyl chloride polymer is characterized in that 0.05 to 0.5% by weight is used. [Chemical 1] [Chemical 2] (In the above formula, each R ¹ may be the same or different,
A hydrogen atom, a lower alkyl group or a nitrile group, each R ² may be the same or different, a hydrogen atom or a lower alkyl group, each R ³ may be the same or different, a hydrogen atom or a halogen atom A substituted or unsubstituted alkyl group or a phenyl group, and X is And Y is And p and r may be the same or different,
Represents an integer of 0 to 6, q represents 0 or 1, and n represents 0 to
Indicates an integer of 500)