JPH072914A - Method for producing vinyl chloride polymer - Google Patents

Abstract

(57) [Summary] [Purpose] Polymerization stability is high, the amount of aggregates is small, and the particle size distribution of the resulting polymer particles is sharp.
Provided is a method for obtaining silicone-vinyl chloride block copolymer particles in a high yield in the range of 0.1 to 50 μm. [Structure] Finely disperse a vinyl chloride-based monomer in water containing an emulsifier, and use 0.8 to 5% by weight of the emulsifier with respect to the vinyl chloride-based monomer for fine suspension polymerization to start oil solubility. A method for producing a vinyl chloride polymer having an average particle diameter in the range of 0.1 to 50 μm, which comprises using a polymer initiator as an agent.

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 a fine particle size.

[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.

Recently, in order to impart weather resistance, abrasion resistance, processability, etc. to a polyvinyl chloride resin, polymerization with a vinyl chloride monomer is carried out using a polymer initiator composed of polysiloxane amide containing an azo group. A silicone-vinyl chloride block copolymer obtained in this way has been proposed (for example, JP-A-61-252230). 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.

[0004]

DISCLOSURE OF THE INVENTION The object of the present invention is that the polymerization stability is high, the amount of agglomerates is small, the particle size distribution of the polymer particles produced is sharp, and the yield is 0.1.
It is to provide a method for obtaining particles of a silicone-vinyl chloride block copolymer in the range of ˜50 μm.

[0005]

The inventors of the present invention have made extensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, the present invention relates to a vinyl chloride monomer (VC
M) is finely dispersed in water containing an emulsifier to carry out fine suspension polymerization.
% By weight, as an oil-soluble initiator, at least constituents represented by the following general formulas (1) and (2) are contained, and each constituent is bound via an ester bond, an amide bond or a urethane bond, and Mw is A method for producing a vinyl chloride polymer having an average particle size in the range of 0.1 to 50 μm, characterized in that a polymer initiator of 2000 to 300000 is used. Hereinafter, the present invention will be described in detail.

[0006]

[Chemical 5]

[0007]

[Chemical 6]

(In the 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 and represents a hydrogen atom or a lower alkyl group. Wherein 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 may be the same or different and each represents an integer of 0 to 6, q represents 0 or 1, and n represents an integer of 0 to 500). The turbid polymerization is a method in which an oil-soluble initiator and VCM are finely dispersed in water using an emulsifier to carry out polymerization. It also includes a seed fine suspension polymerization method in which seed particles are enlarged using pre-synthesized seed particles. In this case, the production method of the present invention may be used for the synthesis of seed particles, or seed fine suspension polymerization may be used. You may use the manufacturing method of this invention at the time of suspension polymerization.

In the polymer initiator used in the present invention, the constitutional unit represented by the general formula (1) and the constitutional unit represented by the general formula (2) are bonded via an ester bond, an amide bond or a urethane bond. A compound having a unit, and examples of such a compound include a polycondensation product of azobiscarboxylic acid and silicone having amino groups at both ends, a polycondensation product of azobiscarboxylic acid and silicone having hydroxyl groups at both ends. Examples thereof include a polycondensation product of an azobis alcohol and a silicone having a carboxylic acid group at both ends, or a polycondensation product of an azobis alcohol and a silicone having a hydroxyl group at both ends and a dicarboxylic acid.

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 pimelic acid. And aliphatic dicarboxylic acids such as 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 polymer initiator is as follows: the azo compound, the silicone compound, or the carboxylic acid group of a dicarboxylic acid is converted to 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 are reacted. Examples thereof include a method of reacting using a condensing agent such as tosyl chloride, carbonyldiimidazole, and methylchloropyridinium iodide.

The polymer initiator used in the present invention preferably has a silicone repeating unit of 500 or less. When the repeating unit exceeds 500, the solution viscosity becomes high when the polymer initiator is dissolved in VCM, so that it becomes difficult to disperse it in water and vinyl chloride polymer particles having a uniform particle size cannot be obtained.

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 2,000, the blocking rate of the silicone block in the vinyl chloride-based polymer decreases, and
When it exceeds 00, the viscosity of the solution when dissolved in VCM becomes high, so that it becomes difficult to disperse it in water, and vinyl chloride polymer particles having a uniform particle size cannot be obtained.

The amount of the polymeric initiator used is preferably 0.01 to 20% by weight based on the charged VCM.

An emulsifier is used in the polymerization of the present invention, and examples of the emulsifier having good polymerization stability for obtaining a target particle size include an amphoteric surfactant, an anionic surfactant or a nonionic surfactant. used. Here, examples of the amphoteric surfactant include those having a carboxylate salt, a sulfate ester salt, a sulfonate salt, a phosphate ester salt in the anion portion and an amine salt or a quaternary ammonium salt in the cation portion. The salts of alkyl betaines include lauryl betaine, stearyl betaine, and 2-undecyl-hydroxyethyl imidazolium betaine, and the amino acid type lauryl-β.
-Alanine, stearyl-β-alanine, lauryldi (aminoethyl) glycine, and dioctyldi (aminoethyl) glycine salts can be mentioned. Examples of the anionic surfactant include sulfuric acid esters of higher alcohols, alkylbenzene sulfonates, aliphatic sulfonates, dialkylsulfosuccinates, alkylnaphthalene sulfonates, and the like. Further, examples of the nonionic surfactant include a conventional polyethylene glycol alkyl ester type, alkyl ether type, and alkyl phenyl ether type surfactant. In addition, these emulsifiers can be used in combination of two or more kinds, and further, a polymeric dispersant such as partially saponified polyvinyl alcohol, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, gelatin, ethyl cellulose and methyl cellulose can be used together. can do.

The amount of emulsifier used was 0.
It is in the range of 8 to 5% by weight. If the amount is out of this range, the desired vinyl chloride polymer particle size may not be obtained. For example, when sodium dodecylbenzenesulfonate is used as the emulsifier, if it is less than 0.8% by weight, the stability of the polymerization is poor due to poor dispersion of the polymer initiator and it tends to aggregate, while if it exceeds 5% by weight. However, the stability of polymerization is not a problem, but when the VCM is collected, it foams, takes a long time to collect, and agglomerates.

In the present invention, the method of finely dispersing VCM in water is not particularly specified, but there are the following methods, for example.
That is, a polymer initiator, an emulsifier, water and VCM are put in a dispersion tank and finely dispersed while stirring at high speed with a homogenizer. After that, while stirring slowly, raise to a predetermined temperature,
Initiate polymerization. The emulsifier may be added to the dispersion tank in the whole amount, or a part of the emulsifier may be added after the initiation of the polymerization.

The polymerization temperature can be selected according to the temperature at the time of ordinary VCM polymerization, and is preferably 30 to 80 ° C.

In the polymerization, the above-mentioned polymer initiator may be used in combination with other polymerization initiators. Examples of the other polymerization initiator include acyl peroxides such as lauroyl peroxide and benzoyl peroxide; tertiary. Examples thereof include peroxyesters of organic acids such as butylperoxypivalate; dioxycarbonates such as diisopropylperoxydicarbonate; azo compounds such as azobisdimethylvaleronitrile or acetylcyclohexylsulfonyl peroxide.

The VCM in the present invention means, in addition to vinyl chloride monomers, vinyl chloride monomers and monomers copolymerizable therewith, such as ethylene, propylene, butene, pentene-1, butadiene and styrene. , Α-methylstyrene, acrylonitrile, vinylidene chloride, vinylidene cyanide, alkyl vinyl ethers, dialkyl maleic acids, carboxylic acid vinyl esters, aryl ethers, fumaric acid esters, N-vinyl pyrrolidone, vinyl pyridine, vinyl silanes, acrylic It may be a mixture of acid alkyl esters, methacrylic acid alkyl esters and the like.

The vinyl chloride polymer thus obtained does not have pores inside the particle and has a single particle shape, unlike particles having an average particle diameter of 70 to several 100 μm produced by a usual suspension polymerization method. Becomes Furthermore, since the blocking rate of the silicone unit is significantly higher than that of the suspension polymerized product, the copolymer obtained by the present invention can be applied to PVC for paste processing alone or as a mixture.

[0026]

EXAMPLES 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 Reference Example 1 (Synthesis Example of Polymer Initiator) 4,4′-Azobis (4-cyanopentanoic acid) 42.0
g was dispersed in 800 ml of dichloromethane, and 1,
A solution prepared by dissolving 53.5 g of 1′-carbonyldiimidazole in 200 ml of dichloromethane was added, and the mixture was stirred at room temperature for reaction. After 1 hour, 670 g of amino-modified polydimethylsiloxane (X-22-161C, manufactured by Shin-Etsu Chemical Co., Ltd., number average molecular weight 4500) was added and reacted at room temperature for 7 hours with stirring.

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. Further, it was confirmed by IR measurement and NMR measurement that this product was the target product (3). Moreover, the molecular weight by GPC was Mw = 84000 and Mn = 34000 in terms of polystyrene.

[0033]

[Chemical 9]

Example 1 In a 2 l pressure-resistant stainless steel container, 1010 g of water, 1.5 parts by weight of sodium dodecylbenzenesulfonate (based on 100 parts by weight of vinyl chloride monomer), and 3 parts by weight of the polymer initiator of Reference Example 1 ( (100 parts by weight of vinyl chloride monomer) was charged, the pressure reduction and nitrogen substitution were repeated several times, 400 g of vinyl chloride monomer was introduced, and this was finely dispersed by a homogenizer at 6200 rpm for 120 minutes. Then, the finely dispersed solution was transferred to a 2 liter stainless steel autoclave, heated to 65 ° C. with stirring at 150 rpm to start polymerization, and cooled when the polymerization pressure dropped to 7.5 kg / cm ² to carry out polymerization. Stopped. As a result, 1420 g of a latex having a solid content concentration of 20% was obtained (yield 71
%). The particle size of the latex was 1.3 μm. Then, the obtained latex was dried with a spray dryer, and the average particle size as shown in Table 1 was 13
A powder of μm was obtained.

Example 2 Instead of sodium dodecylbenzene sulfonate as an emulsifier, partially saponified polyvinyl alcohol (degree of polymerization: 60) was used.
0, saponification degree 80%) 3 parts by weight (vinyl chloride monomer 1
Polymerization was carried out in the same manner as in Example 1 except that the homogenizer conditions were 5000 rpm and 120 minutes, and 1300 g of a latex having a solid content of 15% was obtained (yield). 70%). The latex particle size was 10 μm. Then, the obtained latex was dried with a spray drier to obtain a powder having an average particle diameter of 38 μm as shown in Table 1.

Comparative Example 1 The procedure was carried out except that 0.5 parts by weight of sodium laurylsulfonate (based on 100 parts by weight of vinyl chloride monomer) was used in place of sodium dodecylbenzenesulfonate, and the homogenizer conditions were 6200 rpm and 75 minutes. Example 1
Polymerization was carried out in the same manner as in. As a result, stirring was stopped 4 hours after the polymerization due to an overload due to aggregation.

Comparative Example 2 In a 3 l autoclave made of stainless steel, 46.3 g of the polymer initiator of Reference Example 1, 1505 g of water, and a 3% aqueous solution of partially saponified polyvinyl alcohol (polymerization degree 2600, saponification degree 80%) 38. After charging 6 g and repeating depressurization and nitrogen substitution several times, the depressurization was finally applied to the vinyl chloride monomer 7
70 g were introduced. 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 collecting the unreacted vinyl chloride monomer, the polymer slurry was thoroughly washed with water and dehydrated. Then, this slurry was dried under reduced pressure at 60 ° C. overnight to obtain 575 g of particles. The obtained particles have an average particle size of 165 μm as shown in Table 1 and a bulk specific gravity of 0.55.
It was g / cc.

[0038]

[Table 1]

[0039]

EFFECT OF THE INVENTION According to the fine suspension polymerization method of the present invention, the polymerization stability is high, the number of aggregates is small, and the silicone-vinyl chloride block copolymer, which is a fine particle of 0.1 to 50 μm, is produced in a high yield. And a high blocking rate.

[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 (2)

[Claims] 1. A vinyl chloride monomer is finely dispersed in water containing an emulsifier to carry out fine suspension polymerization, and the emulsifier is used in an amount of 0.8 to 5% by weight based on the vinyl chloride monomer. At least the following general formulas (1) and (2) are used as the solubility initiator.
And a weight average molecular weight (Mw) of 2000 to 300,000, in which each of the constituents is bonded via an ester bond, an amide bond or a urethane bond.
The method for producing a vinyl chloride polymer having an average particle diameter in the range of 0.1 to 50 μm, characterized in that the polymer initiator is used. [Chemical 1] [Chemical 2] (In the 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 and each represents 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, a substituted or unsubstituted alkyl group or a phenyl group, and X represents [Chemical 3] 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) 2. The method for producing a vinyl chloride polymer according to claim 1, wherein another polymerization initiator is used in combination as the polymerization initiator.