JP3261724B2 - Method for producing vinyl chloride polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a vinyl chloride resin. More specifically, the present invention relates to a method for producing a vinyl chloride resin by a fine suspension polymerization method using a specific dispersant system.

[0002]

2. Description of the Related Art A fine suspension polymerization method of a vinyl chloride resin is as follows.
After homogenizing a monomer mainly composed of vinyl chloride, water, an emulsifier, a polymerization initiator soluble in the monomer and other polymerization aids under high shear, polymerize the mixture under stirring, and average the resin. This is a method for producing fine vinyl chloride polymer particles having a diameter of about 0.2 to 3 μm. Therefore, in this method, many methods have been proposed for stabilizing the fine suspension emulsion.

For example, GB 696359 proposes to use a surfactant comprising sodium lauryl sulfate and cetyl alcohol. Tokiko 40-19
No. 591 proposes fine suspension polymerization in the presence of a known emulsifier and a higher alcohol. Japanese Patent Publication No. 56-5243 proposes a method in which an alkyl sulfate and a higher alcohol are used to prepare a dispersion at a temperature higher than the melting point of the higher alcohol. Tokiko Sho 60-59
No. 922 proposes a method in which polymerization is started with a combined system of an emulsifier and a higher alcohol, and then the emulsifier is added during the polymerization. JP-A-3-153712 proposes a method in which a higher alcohol is added before performing the homogenization treatment.

[0004]

However, in the above proposal, the stability of the fine suspension until the completion of the polymerization is insufficient, and the generation of agglomerates and the adhesion to the inner wall of the polymerization apparatus are not small. Therefore, a fine suspension polymerization method in which the stability of the fine suspension is high from the homogenization treatment to the end of the polymerization is provided.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a method for producing a vinyl chloride polymer by finely suspending and polymerizing vinyl chloride or a vinyl monomer mainly composed of vinyl chloride. An aqueous medium containing 0.1 to 10 parts by weight per 100 parts by weight of the monomer of a dispersant system comprising a metal salt and a linear aliphatic higher alcohol, wherein the higher alcohol / alkyl sulfate in the dispersant system is used; The alkali metal salt has a molar ratio of 1.05 to 5, and the higher alcohol is at least one selected from the group consisting of alcohols having 14 to 18 carbon atoms,
At least one selected from the group consisting of 14 alcohols;
05 or more, but not including an alcohol having 14 carbon atoms alone , and aromatic diacyl peroxide,
Aliphatic diacyl peroxide, organic acid peroxyes
Polymerization selected from ter and peroxydicarbonate
A method for producing a vinyl chloride polymer, characterized by using an initiator.

The monomer used in the present invention is vinyl chloride or a vinyl monomer mainly composed of vinyl chloride.

Other monomers other than vinyl chloride include olefins such as ethylene, propylene and α-butene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl laurate and vinyl stearate;
Unsaturated acids such as acrylic acid, methacrylic acid and itaconic acid and their esters, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether and lauryl vinyl ether, maleic acid, fumaric acid and their anhydrides or esters, aromatics Group vinyl, unsaturated nitrile and the like.

[0008] The fine suspension polymerization method used in the present invention includes vinyl chloride or a vinyl monomer mainly composed of vinyl chloride, an aqueous medium containing a dispersant, a polymerization initiator soluble in the monomer, A method of homogenizing with other polymerization aids under high shear and then polymerizing at 20 to 80 ° C. with stirring to produce fine vinyl chloride polymer particles having an average resin diameter of about 0.2 to 3 μm. Is a method of finely suspending and subsequently polymerizing, the method itself may not be even more specific,
Well-known and conventional ones may be used.

The alkali metal salt of the alkyl sulfate and the higher alcohol form a so-called dispersant system.
The amount used is 0.1 to 1 per 100 parts by weight of the monomer.
0 parts by weight. In this range, the amount is appropriately adjusted depending on the amount of water forming the aqueous medium.

The higher straight-chain aliphatic alcohol used in the present invention is a straight-chain aliphatic alcohol having 10 to 18 carbon atoms, and specifically includes decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol. , Cetyl alcohol and stearyl alcohol.

The alkali metal salts of alkyl sulfates used in the present invention include sodium and potassium salts of alkyl sulfates having 8 to 16 carbon atoms such as decyl sulfate, lauryl sulfate and myristyl sulfate.

The ratio of the alkali metal salt of alkyl sulfate to the higher alcohol is such that the mole of the higher alcohol is 1.0 mole per mole of the alkali metal salt of alkyl sulfate.
5 to 5 mol. If the ratio of the higher alcohol is 1.05 mol or less, the stability of the fine suspension is not sufficient, and if it is more than 5 mol, the effect is not so high.

The higher alcohol has 14 to 14 carbon atoms.
At least one selected from the group consisting of 18 alcohols is added to 1 mole of the alkali metal salt of alkyl sulfate.
It is also desirable for the stability of the fine suspension to be at least one mole selected from the group consisting of alcohols having 10 to 14 carbon atoms and at least 0.05 mole.

Although both alcohol groups have 14 carbon atoms, they may belong to any one of the two groups or may be distributed to both groups if the above conditions are met. However, if the alcohol having 14 carbon atoms alone is used as the higher alcohol, the stability of the fine suspension is not sufficient.

The water forming the aqueous medium is not particularly unique, but is about 60-300 per 100 parts by weight of monomer.
Parts by weight.

As the polymerization initiator used in the present invention, those usually used for polymerization of vinyl chloride monomer can be used. For example, benzoyl peroxide, p-
Aromatic diacyl peroxides such as chlorobenzoyl peroxide and 2,4-dichlorobenzoyl peroxide; 5 to 17 carbon atoms such as caproyl peroxide, lauroyl peroxide and 3,5,5-trimethylhexanoyl peroxide Aliphatic diacyl peroxides having an alkyl group of the formula: peroxyesters of organic acids such as t-butylperoxypivalate; peroxydicarbonates such as diisopropylperoxydicarbonate and di-2-ethylhexylperoxydicarbonate; and acetyl Known oil-soluble initiators such as cyclohexylsulfonyl peroxide can be used. These are used alone or in combination of two or more. The amount is about 0.01 to 2 parts by weight based on 100 parts by weight of the monomer.

In the present invention, other polymerization aids include:
Particle size regulators such as sodium sulfate and sodium bicarbonate, chain transfer agents, polymerization inhibitors and the like can be used.

In the homogenization treatment, a homogenizer,
A known device such as a one-stage or two-stage pressurized high-pressure pump, a colloid mill, a centrifugal pump, a homomixer, a vibrating stirrer, a high-pressure jet from a nozzle or an orifice, and ultrasonic waves may be used.

In the polymerization of the present invention, the temperature condition is 20 to 8
It is about 0 ° C., and is performed according to a usual method as described above. Then, the obtained fine suspension of the polymer may be subsequently dried and used as a paste resin, or may be produced so that the oil-soluble polymerization initiator remains in the polymer particles of the fine suspension. The obtained polymer is used as a seed polymer, and a monomer is added in an aqueous medium containing an emulsifier to perform a second-stage polymerization reaction, so-called seeding polymerization.

[0020]

According to the present invention, the obtained fine suspension is stable at the end of polymerization and thereafter. Therefore, generation of aggregates during polymerization can be further reduced. Furthermore, it is stable in the post-treatment after the termination of the polymerization reaction, for example, in the step of recovering the unreacted monomer. Generally, when a fine suspension or emulsion is processed into a paste resin, an emulsifier is further added to stabilize the paste resin. The fine suspension of the present invention has high stability also in this processing. Therefore, a uniform and good paste resin can be obtained.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Evaluation items in the examples are based on the following methods. Polymerization stability: The obtained fine suspension of the polymer is filtered through a 60-mesh wire gauze to obtain an agglomerate on the wire gauze. The amount was expressed in terms of the amount of the aggregated polymer in the amount per 100 parts by weight of the charged monomer. Polymer particle size: Measured using a laser scattering particle size distribution analyzer.・ Stability of fine suspension: Length d of stirring blade and inner diameter D of container
1.3 L of latex was placed in a 5 L flask equipped with a stirrer having a ratio of d / D = 0.5, and a shear force was applied to the latex by stirring at 65 ° C. and 1,000 rpm to completely coagulate from the start of stirring until complete coagulation. The time (minutes) was measured. In addition, what added the 15% solution of the emulsifier sodium lauryl sulfate was also performed. The additional amount is the amount of polymer 1
It is the amount of the emulsifier itself per 100 parts by weight.

The higher alcohols used in the examples are lauryl alcohol (C ₁₂ ), myristyl alcohol (C ₁₄ ), cetyl alcohol (C ₁₆ ), and stearyl alcohol (C ₁₈ ). The amount was represented by a molar ratio with the alkali metal salt of the alkyl sulfate.

Examples 1 and 2 and Comparative Examples 1 and 2 40 kg of deionized water were placed in a tank with a stirrer having an internal volume of 100 L.
100 g of sodium lauryl sulfate, 9.5 g of the higher alcohol and di-2-ethylhexyl peroxydicarbonate of the type and amount shown in Table 1 were charged and degassed, and 25 kg of vinyl chloride monomer was charged. (MA
NTON-GAURIN 150M3-5-TBS manufactured by Menton Gaulin Co., Ltd.) and homogenized. Next, this dispersion is degassed with an internal volume of 10%.
0 L glass-lined polymerization tank (1.5 g / m ² of 1-naphthol sulfide compound as a scale adhesion inhibitor)
And the temperature was raised to 49 ° C. to initiate polymerization.
After about 11 hours, the pressure decreased by 0.5 kg / cm ^2, and the polymerization was terminated, and the unreacted monomers were removed and the contents were taken out. Table 1 shows the evaluation results.

Examples 3 to 6 Comparative Example 3 40 K of deionized water was placed in a dispersion tank having an internal volume of 100 L and equipped with a stirrer.
g, 150 g of sodium lauryl sulfate, 6.3 g of higher alcohol and di-2-ethylhexyl peroxydicarbonate of the type and amount shown in Table 2, and then degassed. The dispersion was homogenized with a high-pressure pump. Next, this dispersion was added to a degassed polymerization tank made of glass lining having an internal volume of 100 L (a 1-naphthol sulfide compound 0.15
g / m ² ), and the temperature was raised to 49 ° C. to initiate polymerization. After about 15 hours, the pressure decreased by 0.5 kg / cm ^2, and the polymerization was terminated, and the unreacted monomers were removed and the contents were taken out. Table 2 shows the evaluation results.

Examples 7 to 10 and Comparative Examples 4 to 9 40 K of deionized water was placed in a dispersion tank having an internal volume of 100 L and equipped with a stirrer.
g, 150 g of sodium lauryl sulfate, 6.5 g of a higher alcohol, di-2-ethylhexyl peroxydicarbonate of the type and amount shown in Table 3, were degassed, and 25 kg of a vinyl chloride monomer was charged. The dispersion was homogenized with a high-pressure pump. Next, this dispersion was put into a degassed 100 L stainless steel polymerization tank (pyrogallol sulfide compound 0.15 g / m ² as a scale adhesion inhibitor).
(Coating), and the temperature was raised to 53 ° C. to initiate polymerization.
After about 15 hours, the pressure decreased by 0.5 kg / cm ^2, and the polymerization was terminated, and the unreacted monomers were removed and the contents were taken out. Table 3 shows the evaluation results.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

Claims (1)

(57) [Claims] In producing a vinyl chloride polymer by subjecting vinyl chloride or a vinyl monomer mainly composed of vinyl chloride to fine suspension polymerization, an alkali metal salt of an alkyl sulfate and a linear aliphatic higher An aqueous medium containing 0.1 to 10 parts by weight per 100 parts by weight of the monomer is used as a dispersant system comprising alcohol and the molar ratio of the higher alcohol to the alkali metal salt of alkyl sulfate in the dispersant system is , 1.05 to 5, and the higher alcohol is at least one selected from alcohol groups having 14 to 18 carbon atoms, and at least one selected from alcohol groups having 10 to 14 carbon atoms. Not less than 0.05, but not including alcohol having 14 carbon atoms , and aromatic
Diacyl peroxide, aliphatic diacyl peroxide
, Organic acid peroxyesters and peroxydicals
A method for producing a vinyl chloride-based polymer, comprising using a polymerization initiator selected from the group consisting of carbonates .