JPH101502A - Vinyl chloride polymer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a latex having a three-peal particle size distribution while dispensing with a latex mixing operation by subjecting a vinyl chloride monomer to emulsion or microsuspension polymn. to give a polymer latex having one maximum polymerizing the monomer in the presence of the above-obtd. latex, and repeating this operation. SOLUTION: A vinyl chloride monomer is subjected to emulsion or microsuspension polymn. to give a vinyl chloride polymer having one maximum in the number-size particle size distribution, In the presence of the polymer, a vinyl chloride monomer is subjected to emulsion or microsuspension polymn. to give a vinyl chloride polymer having two maxima in the number-size particle size distribution. In the presence of the polymer obtd. in the second step, a vinyl chloride monomer is subjected to emulsion or microsuspension polymn. to give a vinyl chloride polymer having three maxima in the number size particle size distribution. Thus a latex having a three-peal particle size distribution can be obtd. easily and conveniently.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride polymer latex having three maximum values in a number-based particle size distribution and a method for producing the same. The vinyl chloride-based polymer latex according to the present invention gives a polymer having a high packing density when dried, and when mixed with a plasticizer or the like, gives a plastisol with good fluidity. In particular, according to the present invention, a vinyl chloride-based polymer latex that can provide a vinyl chloride-based polymer suitable for a paste can be easily produced.

[0002]

2. Description of the Related Art A plastisol prepared by blending a plasticizer or the like with a vinyl chloride polymer for paste is manufactured by coating, dipping, spraying, or other processing methods to produce flooring or wallpaper, and rust-proof coating for automobiles (undercoat). And so on. In the production of flooring and wallpaper, a method of applying this plastisol to a substrate by a method such as knife coating is widely used, and in order to improve productivity, the viscosity of the plastisol, particularly 10 ² sec ⁻¹ or more, is used. It is desired to lower the viscosity in a so-called high shear rate region. In addition, a spray coating method is frequently used for undercoating of automobiles. In this case, too, a low viscosity in a high shear rate region is required to stabilize the spray.

[0003]

As one of the techniques for improving the fluidity of plastisol, it has been proposed to use a vinyl chloride polymer having a plurality of maximum values in a number-based particle size distribution. For example, Japanese Patent Publication No. 61-8843 discloses that a vinyl chloride polymer latex having two maximum values in particle size distribution is mixed and spray-dried. However, a plastisol obtained by blending a plasticizer with the vinyl chloride polymer obtained by this method has a drawback that the viscosity in a high shear rate region is not sufficiently reduced. JP-A-7-53627 discloses that a vinyl chloride-based polymer latex having a maximum value of 3 to 6 particles in a particle size distribution is produced by mixing vinyl chloride-based polymer latexes obtained by different production methods. Is disclosed. Further, JP-A-5-155908 discloses that a plurality of vinyl chloride-based polymer latexes are mixed to form a seed latex having a plurality of maximum values in particle size distribution, and a vinyl chloride-based monomer is added in the presence of the seed latex. It is described that a vinyl chloride-based polymer latex having a plurality of maximum values is produced by polymerizing a polymer.

[0004] However, the method of mixing a plurality of latexes employed in these methods is complicated in operation,
In addition, it is difficult to maintain the stability of the latex. Accordingly, an object of the present invention is to provide a method for easily producing a vinyl chloride polymer latex having three maximum values in the number-based particle size distribution. Another object of the present invention is to provide a vinyl chloride polymer latex which can be easily produced and gives a paste having excellent processability.

[0005]

According to the present invention, first, a vinyl chloride monomer (in the present specification, vinyl chloride monomer means vinyl chloride or other vinyl chloride copolymerizable therewith. (A ratio of vinyl chloride in the mixture is usually 80% by weight or more) by emulsion polymerization or fine suspension polymerization to produce a vinyl chloride polymer latex. Is used as a seed latex to produce a second vinyl chloride-based polymer latex by emulsion polymerization or fine suspension polymerization of a vinyl chloride-based monomer. By performing fine suspension polymerization, a vinyl chloride polymer latex having three maximum values in a number-based particle size distribution can be produced.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail. In the present invention, a vinyl chloride monomer, that is, a mixture of vinyl chloride or a mixture of vinyl chloride and another monomer copolymerizable therewith is used as a raw material. A vinyl chloride polymer having three maximum values in the particle size distribution is produced. Other copolymerizable monomers include vinyl esters such as vinyl acetate, vinyl propionate and vinyl stearate, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether and 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 mixture to be subjected to polymerization may contain two or more of these.

In the present invention, first, in step (I), a vinyl chloride monomer is subjected to emulsion polymerization or fine suspension polymerization by a conventional method to obtain a polymer having one maximum value in the number-based particle size distribution. Produce latex. The emulsion polymerization may be performed in an aqueous medium containing an emulsifier using a water-soluble polymerization initiator.
The fine suspension polymerization may be carried out by dispersing a vinyl chloride monomer into fine droplets using a homogenizer in the presence of an emulsifier, and using an oil-soluble polymerization initiator. As the emulsifier, an alkali metal salt or an ammonium salt such as a higher alcohol sulfate, an alkylbenzene sulfonic acid, or a higher fatty acid is used. Further, an anionic surfactant can be used. These surfactants are 2
More than one species 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% by weight, based on the vinyl chloride monomer.
It is used so that it may be% by weight. Also, as an emulsifying aid,
It is also preferable to use 0.2 to 2% by weight of a higher alcohol having 10 to 18 carbon atoms. As the polymerization initiator, in the case of emulsion polymerization, for example, water-soluble peroxides such as sodium salt, potassium salt, ammonium salt and hydrogen peroxide of persulfate;
Alternatively, a water-soluble redox polymerization initiator composed of such a water-soluble peroxide and a water-soluble reducing agent such as sodium sulfite, sodium pyrosulfite, sodium bisulfite, ascorbic acid, sodium formaldehyde sulfoxylate, and the like are used. In the case of fine suspension polymerization, an oil-soluble polymerization initiator soluble in monomers such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, lauroyl peroxide, t-butylperoxypivalate, or A redox polymerization initiator comprising a combination of these oil-soluble polymerization initiators and the above-mentioned water-soluble reducing agent is used.

These polymerization initiators are used in an amount of 0.01 to 0.5% by weight, especially 0.01 to 0.5% by weight, based on the vinyl chloride monomer.
It is preferred to use an amount of about 0.2% by weight. The polymerization reaction system may further contain a polymerization degree regulator and other auxiliaries. As the polymerization degree regulator, a chain transfer agent such as trichloroethylene, carbon tetrachloride, 2-mercaptoethanol, octyl mercaptan, diallyl phthalate, triallyl isocyanurate, ethylene glycol diacrylate,
A crosslinking agent such as trimethylolpropane trimethacrylate is used.

Other auxiliaries 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 mono- or di-hydrogen phosphates. PH adjusters such as alkali metal hydrogen salts, potassium hydrogen phthalate, and sodium hydrogen carbonate. In any of emulsion polymerization and fine suspension polymerization, the degree of polymerization is usually about 40 to 70 ° C, and the polymerization time is usually 4 to 70 ° C.
It takes about 10 hours. By this polymerization reaction, the same pattern as the particle size distribution pattern of the vinyl chloride polymer latex having one local maximum in the number-based particle size distribution, that is, the polymer latex produced by ordinary emulsion polymerization or fine suspension polymerization. To form a latex. The maximum value is 0.
The particle size is preferably in the range of 3 to 0.6 μm, and the particle size distribution is preferably sharp.

In the present invention, next, in the step (II), the polymer obtained above is used as a seed to carry out emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer in the same manner as described above to obtain a particle size distribution. To produce a polymer latex having two maxima. Emulsion polymerization is preferred from the viewpoint of controlling the reaction and controlling the particle size of the obtained latex. Usually, the polymer latex obtained above is used as a seed without drying. The amount of the polymer latex used is usually 3 to 6% by weight, preferably 3.5 to 5% by weight, based on the total amount of the vinyl chloride monomer and the polymer in the latex. The conditions for the seed polymerization may be the same as the conditions for the polymerization for producing the seed. That is, the polymerization temperature is about 40 to 70 ° C., and the polymerization time is about 3 to 9 hours. Emulsifiers, polymerization initiators and other auxiliaries can be the same as those used in the production of seeds.

Preferably, as the emulsifier, sodium lauryl sulfate or sodium alkylbenzenesulfonate, which has a small amount of new polymer particles and has an action of suppressing aggregation of the polymer particles, is used. Further, as the polymerization initiator, hydrogen peroxide or other water-soluble peroxide is used. These emulsifiers and polymerization initiators are preferably added continuously to the reaction system during the emulsion polymerization reaction.

In the sheet polymerization, a seed enlargement reaction and a new polymer particle formation reaction are caused at the same time, and a polymer latex having two maximum values in a number-based particle size distribution is generated. That is, this seed polymerization
If no seed is present, it is done to give a latex with one maximum, preferably a latex with one maximum and a sharp particle size distribution. The two maxima are 0.2-0.5 μm and 0.7
Preferably it is in the particle size range of ~ 1.6 [mu] m.

In the present invention, as the step (III), the latex having two maximum values in the particle size distribution obtained above is used as a seed, and emulsion polymerization of a vinyl chloride monomer is carried out in the same manner as described above. Fine suspension polymerization is performed to produce a polymer latex having three maximum values in the particle size distribution. Also in this case, it is preferable to carry out emulsion polymerization in view of easy control of the reaction and control of the particle size of the obtained latex. The seed polymer latex is preferably used as it is without drying. The amount of the polymer latex to be used is usually 4 to 12% by weight, preferably 6 to 10% by weight, based on the total amount of the vinyl chloride monomer and the polymer in the polymer latex.

This seed polymerization can be carried out under the same conditions as those for the above-mentioned seed polymerization. Polymerization temperature is 40-70 ° C
And the polymerization time is about 3 to 8 hours. Emulsifiers, polymerization initiators and other auxiliaries may be the same as those used for the seed polymerization. Also in this seed polymerization, it is necessary to continuously add an emulsifier such as sodium lauryl sulfate and sodium alkylbenzene sulfonate and a polymerization initiator such as hydrogen peroxide and other water-soluble peroxide to the reaction system during the polymerization reaction. preferable. Also in this seed polymerization, a seed enlargement reaction and a new polymer particle formation reaction occur simultaneously, and a polymer latex having three maximum values in the number-based particle size distribution is generated. That is, the seed polymerization is also performed so as to provide a latex having one local maximum if no seed is present.

The three maximum values of the vinyl chloride polymer latex obtained in the present invention are 0.1 to 0.4 μm, 0.6
It is preferable that the particle diameter is in the range of from 1.0 μm to more than 1.0 μm to 2.0 μm. Particularly preferred polymer latexes have maxima from 0.1 to 0.4 μm, 0.6 to 1.0 μm and more than 1.0 μm to 2.0 μm, and lie between these three maxima. Of the two minimum values, the weight of the particles smaller than the smaller minimum value of the particle size is 10 to 50% by weight of the whole polymer, and the weight of the particles larger than the minimum value of the larger particle size is the whole polymer. Latex accounts for 30 to 40% by weight. Latex having such a particle composition shows a low viscosity in a high shear rate region,
Gives plastisol with good workability.

The vinyl chloride polymer latex having three maximum values produced by the method of the present invention is subjected to a commercialization process such as drying and pulverization by a conventional method to obtain a vinyl chloride polymer of the product. At that time, if necessary, a usual adjusting emulsifier, an antioxidant and other auxiliaries, a modifier, and the like may be added. In addition, the vinyl chloride polymer thus obtained is used as a compounding agent such as a plasticizer, an organic solvent, a stabilizer, a filler, an antioxidant, an ultraviolet absorber, an antistatic agent, a colorant, and a release agent. Is appropriately blended and used as a plastisol or organosol. In the present invention, the particle size distribution of the vinyl chloride polymer is measured by a MATEC APPLIED which is a capillary type submicron particle size distribution analyzer.
It shall be measured using CHDF-1100 manufactured by SCIENCES.

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited by the following Examples as long as the gist of the present invention is not exceeded. In the examples, "%" represents "% by weight" unless otherwise specified. Example 1 The following steps (I), (II) and (III) were performed to obtain a vinyl chloride polymer latex.

Step (I): 90 kg of deionized water at a temperature of 54 ° C. was placed in a polymerization vessel having a capacity of 300 liters equipped with a stirrer.
10 g of potassium persulfate, 50 g of sodium pyrosulfite and 22 g of sodium lauryl sulfate as an initial emulsifier were charged, degassed, and dissolved by stirring for about 20 minutes. Then, 60 kg of vinyl chloride was charged into the polymerization can, stirred and emulsified, and the temperature in the can was adjusted to 50 ° C. Fifteen minutes after the completion of the charging of vinyl chloride, a total of 10 g of potassium persulfate was converted into a 0.2% potassium persulfate aqueous solution until the polymerization reaction was completed while controlling the polymerization reaction rate to be constant. Was added. Further, when the polymerization rate reaches about 15%, a 10% aqueous solution of sodium lauryl sulfate is added for about 80 m.
The addition was performed at a rate of 1/10 minutes, and the addition was continued until the total amount of sodium lauryl sulfate added reached 360 g. The pressure in the can is 1960 hPa from the saturation pressure of vinyl chloride at 50 ° C.
(2 kg / cm ² ) The reaction was stopped at the time of dropping, and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. This latex was composed of particles having a sharp particle size distribution having a maximum value of the particle size distribution at a position where the particle size was 0.35 μm, and the stability was good.

Step (II): A 300 liter polymerization tank equipped with a stirrer is charged with 80 kg of deionized water and 3.0 kg of the vinyl chloride polymer latex prepared in the above step (I) in solid content. Thereafter, the mixture was degassed, and 77.0 kg of vinyl chloride was added to emulsify. After the temperature in the can was raised to 55 ° C., a redox polymerization initiator of hydrogen peroxide-sodium formaldehyde sulfoxylate was continuously added so that the total addition amount was 0.05% based on vinyl chloride. Further, when the polymerization rate reaches 10% with respect to the total amount of the seed polymer and vinyl chloride, the total amount is 500 g.
Of sodium lauryl sulfate was continuously added as a 10% aqueous solution at a rate of about 0.08% per hour with respect to vinyl chloride.

The reaction was stopped when the pressure in the vessel dropped 980 hPa (1 kg / cm ² ) from the saturation pressure of vinyl chloride at 55 ° C., and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. Was. The particle composition of the vinyl chloride polymer in the latex has a particle size of 0.30 μm and 0.95 μm.
A maximum value was shown at two points of μm, and two peaks were independent of each other in the particle size distribution curve. The weight of particles larger than the minimum existing between the maximums was 78% of the polymer weight, and the weight of particles smaller than the minimum was 22% of the polymer weight.

Step (III): A polymerization vessel having a capacity of 300 liters equipped with a stirrer is charged with 80 kg of deionized water and 8 kg of a solid content of the vinyl chloride polymer latex prepared in the above step (II). Degas to 72k vinyl chloride
g was added and emulsified. After raising the temperature inside the can to 55 ° C,
A redox polymerization initiator of hydrogen peroxide-sodium formaldehyde sulfoxylate was continuously added so that the total amount was 0.05% based on vinyl chloride. Further, when the polymerization rate reaches 15% with respect to the total amount of the seed polymer and vinyl chloride, a total of 500 g of sodium lauryl sulfate is added to a 10% aqueous solution at a rate of about 0.10% per hour with respect to vinyl chloride. Was added continuously.

The reaction was stopped when the pressure in the vessel dropped 980 hPa (1 kg / cm ² ) from the saturation pressure of vinyl chloride at 55 ° C., and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. Was. The particle composition of the vinyl chloride polymer in the latex is 0.13 μm, 0.65 μm in particle size.
The maximum value was shown at three points of m and 1.46 μm, and the three peaks in the particle size distribution curve showed a so-called independent three-peak particle size distribution. The weight of the particles larger than the minimum between 0.65 μm and 1.46 μm is 33% of the total polymer.
%, The weight of the particles smaller than the minimum between 0.13 μm and 0.65 μm was 31% of the total polymer. Example 2 The following steps (I), (II) and (III) were performed to obtain a vinyl chloride polymer latex.

Step (I): 75 kg of deionized water, 100 g of lauroyl peroxide, 5 g of sodium lauryl sulfate were placed in a 300-liter premixing tank equipped with a stirrer and an emulsifier (Manton-Gaulin type high-pressure homogenizer).
After adding 58 g and 400 g of lauryl alcohol and then degassing the premixing tank, 60 kg of vinyl chloride was added, and the mixture was kept at 35 ° C. with uniform stirring. Next, using an emulsifier, a primary pressure of 14.8 MPa and a secondary pressure of 5.0 MPa.
While dispersing into fine droplets under the conditions described above, the dispersion was transferred to a 300-liter polymerization can equipped with a stirrer that had been previously degassed. After the transfer of the dispersion is completed, the temperature of the
C., and the polymerization was started under stirring. The pressure inside the can is 5
980 hPa (1 kg) from the saturated pressure of vinyl chloride at 5 ° C.
/ Cm ² ), the reaction was stopped when it was lowered, and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. This latex consisted of a polymer with a sharp particle size distribution with a maximum at 0.48 μm.

Step (II): The procedure of Example 1 was repeated except that the vinyl chloride polymer latex obtained in the above step (I) was used in an amount of 4.0 kg in solid content and the amount of vinyl chloride added was changed to 76 kg. Seed polymerization was carried out in the same manner as in step (II) to obtain a vinyl chloride polymer latex. The particle composition of the vinyl chloride polymer in the latex is 0.35 μm in diameter.
The maximum value was shown at two points, m and 1.19 μm, and the particle size distribution curve showed a so-called two-peak particle size distribution in which two peaks were independent. The weight of particles larger than the minimum existing between the two maximums was 70% of the polymer weight, and the weight of particles smaller than the minimum was 30%.

Step (III): A polymerization vessel having a capacity of 300 liters equipped with a stirrer is charged with 80 kg of deionized water and 8 kg of a solid content of the vinyl chloride polymer latex prepared in the above step (II). Degas to 72k vinyl chloride
g was added and emulsified. After raising the temperature inside the can to 55 ° C,
A redox polymerization initiator of hydrogen peroxide-sodium formaldehyde sulfoxylate was continuously added so that the total amount was 0.05% based on vinyl chloride. Further, when the polymerization rate reaches 15% with respect to the total amount of the seed polymer and vinyl chloride, a total of 500 g of sodium lauryl sulfate is added to a 10% aqueous solution at a rate of about 0.10% per hour with respect to vinyl chloride. Was added continuously.

The reaction was stopped when the pressure in the vessel dropped 980 hPa (1 kg / cm ² ) from the saturation pressure of vinyl chloride at 55 ° C., and unreacted vinyl chloride was recovered to obtain a vinyl chloride polymer latex. Was. The particle composition of the vinyl chloride polymer in the latex is 0.19 μm, 0.71 μm in diameter.
And a maximum value at three points of 1.68 μm, and the particle size distribution curve showed a so-called three-peak particle size distribution in which three peaks were independent. The weight of particles larger than the minimum between 0.71 μm and 1.68 μm is 38% of the total polymer,
The weight of particles smaller than the minimum between 0.19 μm and 0.71 μm was 25% of the total polymer.

[0028]

According to the present invention, it is possible to easily produce a latex with three-particle size distribution without performing the mixing operation of the latex.

Continued on the front page (51) Int.Cl. ⁶ Identification code Reference number in the agency FI Technical display location C08F 285/00 MQX C08F 285/00 MQX

Claims (6)

[Claims] 1. A method for producing a vinyl chloride polymer latex by emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer, comprising the following steps (I), (II) and (III): Passing through the process to produce a vinyl chloride polymer latex having three maximum values in the number-based particle size distribution. Step (I): Emulsion polymerization or fine suspension polymerization of a vinyl chloride-based monomer to produce a vinyl chloride-based polymer having one maximum value in a number-based particle size distribution. Step (II): Emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer in the presence of the vinyl chloride polymer obtained in Step (I) to obtain two peaks in the number-based particle size distribution. A vinyl chloride polymer having a specific value is produced. Step (III): Emulsion polymerization or fine suspension polymerization of a vinyl chloride-based monomer in the presence of the vinyl chloride-based polymer obtained in Step (II) to obtain three peaks in a number-based particle size distribution. A vinyl chloride polymer having a specific value is produced. 2. The method according to claim 1, wherein the amount of the vinyl chloride polymer in the step (II) is 3 to 6% by weight based on the total amount of the vinyl chloride polymer and the vinyl chloride monomer. The method of claim 1. 3. The method according to claim 1, wherein the amount of the vinyl chloride polymer in the step (III) is 4 to 12% by weight based on the total amount of the vinyl chloride polymer and the vinyl chloride monomer. The method according to claim 1. 4. The three maximum values each have a particle size of 0.1 to 0.1.
2. The method according to claim 1, wherein the thickness is in a range from 0.4 μm, 0.6 to 1.0 μm and more than 1.0 μm to 2.0 μm.
A method according to any one of claims 1 to 3. 5. The weight of particles having a particle size smaller than the smaller one of the two local minimums existing between the three local maximums is 10 to 50% by weight of the whole polymer, 5. The method according to claim 1, wherein the weight of the particles having a particle size larger than the minimum value accounts for 30 to 40% by weight of the whole polymer. 6. A vinyl chloride-based polymer latex, wherein the polymer has three maximum values in a number-based particle size distribution, each of which has a maximum value of 0.1 to 0.4 μm.
m, exceeding 0.6 to 1.0 μm and 1.0 μm to 2.0 μm
m, and the weight of particles having a particle size smaller than the smaller one of the two local minimums existing between these local maximums is 10 to 50% by weight of the whole polymer, A vinyl chloride polymer latex, wherein the weight of particles having a particle size larger than the larger minimum value accounts for 30 to 40% by weight of the whole polymer.