JPH1112324A - Vinyl chloride-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vinyl chloride polymer for paste having good storage stability, high gelation and melting rate, and low production cost. SOLUTION: A vinyl chloride monomer is prepared in the presence of an emulsifier.
A plastisol, which is a vinyl chloride polymer obtained by polymerizing a water-soluble polymerization initiator in an aqueous medium and comprising 100 parts by weight of the vinyl chloride polymer and 42 parts by weight of di-2-ethylhexyl phthalate, at 3 ° C. / Temperature from room temperature in 60 minutes
Wherein the light transmittance of the plastisol having a thickness of 0.48 mm at the time when the temperature reaches 90 ° C., 90 ° C., and 120 ° C. is 3% or less, 10% or more, and 15% or more, respectively. Offer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vinyl chloride polymer for pastes. In particular, the present invention relates to a vinyl chloride polymer for pastes having good storage stability, high gelation and high melting rate. According to the present invention, it is possible to easily produce a vinyl chloride polymer latex suitable for a paste such as a wallpaper.

[0002]

2. Description of the Related Art A vinyl chloride polymer for a paste is mixed with a plasticizer, a stabilizer, various additives, and the like, to form an organosol or a plastisol (hereinafter, referred to as "sol"). The obtained sol is shaped by a method such as coating, dipping, rotational molding, and gelation by heating,
Melted into various products. The properties required of the sol include that the viscosity of the sol increases or does not gel at temperatures around room temperature from the viewpoint of storage stability, and that the sol rapidly gels and melts when heated from the viewpoint of moldability. It has been demanded. The use of a copolymerized vinyl chloride-based polymer such as a vinyl acetate-vinyl chloride copolymer can increase the gelation and melting rate, but has problems such as high production cost and poor thermal stability. there were.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vinyl chloride polymer for pastes having good storage stability, a high gelation and melting rate, and a low production cost.

[0004]

The present invention relates to a vinyl chloride polymer obtained by polymerizing a vinyl chloride monomer in an aqueous medium in the presence of an emulsifier using a water-soluble polymerization initiator. A plastisol composed of 100 parts by weight of a vinyl polymer and 42 parts by weight of di-2-ethylhexyl phthalate was heated from room temperature at a rate of 3 ° C./min to reach 60 ° C., 90 ° C. and 120 ° C. A light-transmittance having a thickness of .48 mm is 3% or less, 10% or more, and 15% or more, respectively.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The sol using the vinyl chloride polymer of the present invention has good storage stability, and has a high gelling and melting rate (ie,
Good moldability. ). A desirable gelling pattern of the sol from the viewpoint of storage stability and moldability is that, for example, when the sol is heated at a rate of 3 ° C./min, the gelation hardly progresses in the range of room temperature to 60 ° C. It is a pattern in which gelation actually starts in the temperature range of ° C, and at the same time as the gelation starts, gelation progresses at a stretch to a certain extent. At 120 ° C, gelation further progresses to form a relatively uniform gel.

The sol at room temperature is white and turbid and hardly transmits light, but becomes transparent and transmits light as gelation proceeds. Therefore, the degree of gelation can be quantitatively grasped by measuring the light transmittance. The vinyl chloride polymer of the present invention is prepared by heating a plastisol consisting of 100 parts by weight of the polymer and 42 parts by weight of di-2-ethylhexyl phthalate from room temperature at 3 ° C./min.
Vinyl chloride polymer satisfying that the light transmittance of 0.48 mm thickness of the plastisol at the time of reaching 90 ° C., 90 ° C., and 120 ° C. is 3% or less, 10% or more, and 15% or more, respectively. It is.

When the sol reaches 60 ° C., 90 ° C., and 120 ° C., the preferred ranges of the light transmittance are 1% or less, 13% or more, and 18% or more, respectively. If the light transmittance at 60 ° C. exceeds 3%, storage stability may be poor. If the light transmittance at 90 ° C. is less than 10%, energy saving and high speed If the light transmittance at the time when the temperature reaches 120 ° C. is less than 15%, moldability such as foam moldability tends to be inferior.

As the vinyl chloride monomer constituting the vinyl chloride polymer to be used in the present invention, vinyl chloride alone is preferable, but if it is a small amount (for example, 2% by weight).
Hereinafter, a mixture of other monomers copolymerizable with vinyl chloride may be used. Other monomers that can be copolymerized include vinyl acetate, vinyl propionate, vinyl esters such as vinyl stearate, methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether, vinyl ethers such as lauryl vinyl ether, acrylic acid, methacrylic acid, Examples include unsaturated carboxylic acids such as itaconic acid and alkyl esters thereof, vinylidene chloride, unsaturated nitrile and the like. The vinyl chloride-based monomer may contain two or more of these.

The emulsifiers used in the present invention include alkali metal and ammonium salts such as higher alcohol sulfates, alkylbenzene sulfonic acids and higher fatty acids. Also, an anionic surfactant can be used. Two or more of these surfactants can be used in combination, and a nonionic surfactant can be used in combination with them. These emulsifiers are used in an amount of usually 0.1 to 3% by weight, preferably 0.3 to 1.5% by weight, based on the vinyl chloride monomer.
It is used so that it may be% by weight. Further, as an emulsifier, a higher alcohol having 10 to 18 carbon atoms is further added in an amount of 0.2 to 2% by weight.
It is also preferable to use them in combination.

As the polymerization initiator, for example, a water-soluble peroxide such as sodium salt, potassium salt, ammonium salt or hydrogen peroxide of persulfuric acid is used. Further, a water-soluble redox polymerization initiator comprising a water-soluble peroxide and a water-soluble reducing agent such as sodium sulfite, sodium pyrosulfite, sodium bisulfite, ascorbic acid, and sodium formaldehyde sulfoxylate may also be used. These polymerization initiators are preferably used in an amount of about 0.01 to 0.5% by weight, particularly about 0.01 to 0.2% by weight, based on the vinyl chloride monomer. The polymerization reaction system may further contain a polymerization degree regulator and other auxiliaries. As the polymerization degree regulator, trichloroethylene, carbon tetrachloride,
Chain transfer agents such as 2-mercaptoethanol and octylmercaptan, and crosslinking agents such as diallyl phthalate, diallyl isophthalate, diallyl terephthalate, triallyl isocyanurate, ethylene glycol diacrylate, and trimethylolpropane trimethacrylate are used. Other auxiliary agents include, for example, water-soluble transition metal salts such as cupric chloride, ferrous sulfate, and nickel nitrate, which act as activators for redox polymerization initiators, and monohydrogen phosphate or dihydrogen alkali metal salts. And pH adjusters such as potassium hydrogen phthalate and sodium hydrogen carbonate.

In order to obtain the vinyl chloride polymer of the present invention,
Although various methods are possible, a particularly preferred method is to polymerize the vinyl chloride monomer at a higher temperature than usual, when polymerizing the vinyl chloride-based monomer using a water-soluble polymerization initiator in an aqueous medium in the presence of an emulsifier. can get. In particular, the polymerization reaction temperature is 5
The temperature is preferably 7 to 80 ° C, more preferably 60 to 80 ° C.
７５75 ° C. If the polymerization reaction temperature is less than 57 ° C, 60
The light transmittance of the blastisol according to claim 1 at the time when the temperature reaches 90 ° C. or 90 ° C. is difficult to satisfy the conditions of claim 1, and the polymerization degree of the vinyl chloride polymer obtained when the polymerization reaction temperature exceeds 80 ° C. Is too low, and the mechanical properties are deteriorated.

Further, the aqueous dispersion of the vinyl chloride polymer obtained at the above-mentioned polymerization reaction temperature is rapidly frozen at a temperature of 0 ° C. or lower, and sublimation and separation of only water are carried out under reduced pressure. In this case, no thermal energy is applied to the vinyl chloride-based polymer, the vinyl chloride-based polymer particles do not fuse with each other, a pulverizing step is not required, and the obtained sol has excellent gelation and melting properties. However, this method has poor productivity and is not industrially common. As a preferable drying method, the vinyl chloride polymer is dried at a drying temperature of 110 to 160 ° C. using a known spray drying device such as a rotating disk, a pressure nozzle, and a two-fluid nozzle. Drying temperature is 1
When the temperature is lower than 10 ° C., a large amount of energy and time are required for drying. When the drying temperature is higher than 160 ° C., fusion between vinyl chloride polymers occurs, and the gelation of the sol and the melting characteristics are apt to deteriorate. .

[0013]

The present invention will be specifically described below with reference to examples. The evaluation method performed here is as follows. (1) Light transmittance Two glass plates provided with a space of 0.48 mm were placed on a sample table equipped with a hot plate, and a thermocouple was set at the bottom. He-Ne gas laser (wavelength 633)
nm, manufactured by NEC Corporation GLS-536
0) and a polarizing filter for adjusting the amount of light, a pin photodiode (S1190-03, manufactured by Hamamatsu Photonics KK) is set at the bottom of the sample stage, and the output of the thermocouple and the output of the pin photodiode can be taken into a personal computer. , Amplifier and other interfaces were connected.
The sample stage is covered with a light-shielding film, the laser light source switch is turned on, and the pin photodiode output via the amplifier is 15 V
After adjusting the light amount by rotating the polarizing filter so as to obtain a sol (100 parts by weight of a vinyl chloride polymer, phthalic acid di-phthalate) mixed and degassed at room temperature between two glass plates at a room temperature. (42 parts by weight of 2-ethylhexyl) was set so as to prevent air bubbles from entering. The film was covered again with a light-shielding film, and the temperature was increased at 3 ° C./min. (2) Average degree of polymerization Measured according to the method of JIS K-6721. (3) Evaluation of gelling property of plastisol 100 parts by weight of a vinyl chloride polymer and 70 parts by weight of di-2-ethylhexyl phthalate were blended, and stirred and mixed using a chemister to obtain a plastisol. This plastisol was degassed under vacuum and left at 25 ° C. in an atmosphere of 50% RH for 2 hours. A predetermined amount of this plastisol was collected in a glass tube having a diameter of 20 mm, and heated in an oil bath at 100 ° C. for a certain period of time using a B8R type viscometer manufactured by Tokimec Co., Ltd. (using a # 7 rotor). Rotation speed 10r per interval
The viscosity in pm was measured. As the gelation progresses, a significant increase in viscosity occurs, making it impossible to measure the viscosity.
800 poises or more were gelled.

Example 1 Seed Emulsion Polymerization A 200-liter internal volume polymerization tank equipped with a stirrer was charged with 90 kg of deionized water at a temperature of 70 ° C., 10 g of potassium persulfate and 75 g of anhydrous sodium bisulfite, and stirred for 20 minutes. To dissolve. Next, the inside of the polymerization tank was 250 mmHg.
And kept at 70 ° C. for 20 minutes. Next, 60 kg of a vinyl chloride monomer was charged into the polymerization tank, and the temperature in the tank was set at 67 ° C.
Adjusted to ° C. 15 minutes after charging the vinyl chloride monomer, when a 0.2% aqueous potassium persulfate solution previously dissolved is added at a rate of 10 cc / min, and the polymerization conversion reaches 15%. Then, the addition of a separately dissolved 8% aqueous solution of sodium lauryl sulfate was started, and the aqueous solution was added at a rate of about 20 cc / min until the total amount of sodium lauryl sulfate added reached 300 g. Tank pressure is 67
2.0 kg / c from saturation pressure of vinyl chloride monomer at ℃
When the m2 dropped, the addition of the aqueous potassium persulfate solution was stopped to terminate the polymerization reaction, and the unreacted monomer was recovered to obtain a polymer dispersion. The average particle size of the polymer particles in the resulting dispersion was monodisperse particles of 0.48 μm.

Seed Emulsion Polymerization A 200-liter internal volume polymerization tank equipped with a stirrer was charged with 4.5 kg of the above-mentioned polymer (in terms of solid content), 80 kg of deionized water and 50 g of anhydrous sodium bisulfite as a seed polymer. . The pressure in the polymerization vessel was reduced to 250 mmHg, 75.5 kg of vinyl chloride monomer was charged, and the temperature in the vessel was adjusted to 67 ° C. Then 0.2% of potassium persulfate
% Aqueous solution was added at a rate of 40 cc / min for 15 minutes, and thereafter added continuously while controlling the addition rate so as to maintain a constant polymerization rate. 8% of sodium lauryl sulfate from the time the polymerization conversion reaches 10% to the end of polymerization
The aqueous solution was continuously added at a rate of 0.7 liter / hour (the total amount of sodium lauryl sulfate added was 400 g). When the pressure in the tank dropped 1.0 kg / cm 2 from the saturation pressure of the vinyl chloride monomer at 67 ° C., the polymerization was stopped, and the unreacted monomer was recovered. The average particle size of the vinyl chloride polymer particles in the obtained dispersion was 1.2 μm. This dispersion was dried and pulverized with a rotating disk type spray dryer under the conditions of an inlet temperature of 120 ° C. and an outlet temperature of 52 ° C. to obtain a vinyl chloride polymer, which was evaluated. Table 1 shows the evaluation results.

Example 2 Seed emulsion polymerization was carried out in the same manner as in Example 1 except that the amount of potassium persulfate initially added was 1 g, and a monodispersed vinyl chloride polymer dispersion having an average particle diameter of 0.7 μm was obtained. I got This was dried and pulverized in the same manner as in Example 1 to obtain a vinyl chloride polymer, which was evaluated. Table 1 shows the evaluation results.

<Example 3> Stirrer and emulsifier (Manton-Gaulin type high-pressure homogenizer: pressure 130 kg / cm)
50 kg of deionized water, 70 g of lauroyl peroxide and 100 g of lauryl alcohol were placed in a 200 liter prepolymerization tank equipped with 2G), and dissolved by stirring for 20 minutes. Next, after the pressure in the polymerization tank was reduced to 250 mmHg, 20 kg of a vinyl chloride monomer was charged and maintained at 35 ° C. with uniform stirring. Next, while dispersing the content liquid in this pre-polymerization tank into fine droplets using an emulsifier,
After adding 50 kg of deionized water in advance, the mixture was transferred to a 200-liter polymerization tank equipped with a stirrer that had been degassed. After the transfer of the content liquid, the temperature of the polymerization tank was raised to 67 ° C., and polymerization was started with stirring. When the polymerization conversion reached 10%, 50 kg of vinyl chloride monomer was added at a rate of 15 kg / hour. When the polymerization conversion reaches 15%, the addition of a separately dissolved 8% aqueous solution of sodium lauryl sulfate is started, and the aqueous solution is added at a rate of about 10 cc / min until the total sodium lauryl sulfate reaches 300 g. Was added. Thereafter, a vinyl chloride polymer was obtained in the same manner as in Example 1, and evaluation was performed using this. Table 1 shows the evaluation results. The polymer particles in the dispersion had an average particle size of 1.0 μm
Were continuously distributed particles.

<Comparative Examples 1 to 3> The following commercially available products were evaluated. Table 1 shows the evaluation results. Comparative Example 1: "PSL684" manufactured by Kanebuchi Kogyo Co., Ltd. Comparative Example 2: "R241" manufactured by Tosoh Corporation Comparative Example 3: "P452" manufactured by Mitsubishi Chemical Corporation

[0019]

[Table 1]

[0020]

The vinyl chloride polymer of the present invention has good storage stability of the sol, and has a high gelation and melting speed.
It can be suitably used for other paste sols for foaming.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiya Watanabe 1 Toho-cho, Yokkaichi-shi, Mie Inside of Yokkaichi Research Institute, Mitsubishi Chemical Corporation

Claims (2)

[Claims] 1. A method for producing a vinyl chloride monomer in the presence of an emulsifier,
A plastisol, which is a vinyl chloride polymer obtained by polymerizing a water-soluble polymerization initiator in an aqueous medium and comprising 100 parts by weight of the vinyl chloride polymer and 42 parts by weight of di-2-ethylhexyl phthalate, at 3 ° C. / Temperature from room temperature in 60 minutes
The plastisol has a light transmittance of 0.48 mm thick at the time of reaching 90 ° C., 90 ° C., and 120 ° C., respectively, being 3% or less, 10% or more, and 15% or more. Coalescing. 2. The vinyl chloride polymer according to claim 1, wherein the polymerization temperature is 60 to 75 ° C.