JP2533797B2 - Process for producing vinyl chloride polymer composition for paste dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Purpose of the Invention [Field of Industrial Application] The present invention relates to a chloride for paste dispersion which can provide a vinyl chloride polymer product having improved thermal stability and whitening property by water absorption. The present invention relates to a vinyl polymer composition, particularly a vinyl chloride polymer composition for preparing a paste dispersion liquid such as plastisol or organosol.

[Conventional technology]

Vinyl chloride polymer for paste is usually an emulsion polymerization method using a water-soluble polymerization initiator, or dissolved in vinyl chloride monomer, mechanically vinyl chloride monomer using a so-called oil-soluble polymerization initiator. It is produced by a fine suspension polymerization method in which it is uniformly and finely dispersed in water (if necessary, further homogenized) and then polymerized. Vinyl chloride polymer for paste obtained by such a method,
For example, plastisol or organosol by mixing or kneading a plasticizer, a diluent, a stabilizer, etc., or a pyrolyzable organic foaming agent or a foaming aid called "Kitsuker" which lowers the decomposition temperature of the foaming agent depending on the application. It is used in a large amount for forming flooring, wallpaper, ceiling coverings, leather products, etc. by appropriately shaping and gelling by heating.

Further, such a vinyl chloride polymer for paste is required to have excellent thermal stability during molding / processing of the product or use of the product. Further, in the case of a transparent product, it is also required that there is no defect that it loses transparency due to water absorption and whitening when it is immersed in water or used under conditions where it is exposed to a large amount of water.

Heretofore, there have been many proposals for improving such thermal stability and water absorption whitening property of a vinyl chloride polymer for paste.
For example, JP-A-55-80445 and JP-A-59-15294.
JP-A-1 discloses that in order to improve the thermal stability of a halogen-containing resin such as a vinyl chloride-based polymer during molding, hydrotalcites, particularly BET specific surface area of the resin is 30 m ² / g or less, and It is described that hydrotalcites treated with decrystallized water are contained together with a tin stabilizer and stearyl alcohol. Further, JP-A-62-43447 discloses that a fatty acid-based emulsifier is contained and an alkali metal content is
It is described that by adding hydrotalcites and a specific stabilizer to a vinyl chloride resin for paste of 500 ppm or less, its thermal stability and water whitening property by absorption are improved.

In addition, the present inventors have added a low-viscosity paste (plastisol, etc.) by adding hydrotalcites before the initiation of polymerization or during the initial stage of polymerization (polymerization conversion of 50% or less) during the production of a vinyl chloride polymer. ), And a method for producing a vinyl chloride polymer which gives a product having improved thermal stability and whitening property after water absorption (Japanese Patent Application No. 62-231594 (JP-A-1-74203)). ]. Particularly, in the examples, it is described that hydrotalcites added in advance to an aqueous slurry or emulsion are added. However, since the water used in this case does not use deionized water, it has a drawback that it is inferior in water-absorption whitening property and that preparing an emulsion of hydrotalcites is complicated in the production operation.

[Problems to be solved by the invention]

The present invention further improves the above-mentioned proposed inventions of the present inventors to provide a vinyl chloride polymer composition for a paste dispersion, which can provide a product with improved thermal stability and water whitening property by absorption. An object of the present invention is to provide a method of manufacturing easily with a simple operation.

(B) Structure of the Invention [Means for Solving the Problems] The inventors of the present invention have conducted various studies to solve the above problems, and as a result, hydrotalcites were simply slurried in deionized water. It was possible to solve the above-mentioned problems by dispersing and adding to the above.

That is, the method for producing a vinyl chloride-based polymer composition for a paste dispersion of the present invention comprises emulsion polymerization or fine suspension polymerization of vinyl chloride alone or a mixture of vinyl chloride and another monomer copolymerizable therewith. In the method for producing a vinyl chloride-based polymer composition for a paste dispersion by containing hydrotalcites in the paste-formable vinyl chloride-type polymer obtained by the method, as a means for containing the hydrotalcites The method is characterized by using a method of adding hydrotalcites in the form of an aqueous slurry in which deionized water is dispersed before the initiation of polymerization, during the polymerization, or at any time after the completion of the polymerization reaction.

The polymerization reaction of the vinyl chloride polymer in the present invention is carried out by the emulsion polymerization method or the fine suspension polymerization method as described above. The monomer used is vinyl chloride alone or a mixture of vinyl chloride and another monomer copolymerizable therewith. Other monomers that can be used include, for example, olefins such as ethylene, propylene and n-butene, vinyl acetate, vinyl propionate, vinyl stearate and other vinyl esters, acrylic acid, methacrylic acid and itacone. Monounsaturated acids such as acids, alkyl esters of these monounsaturated acids, vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether and lauryl vinyl ether, polyunsaturated acids such as maleic acid and fumaric acid, etc. Examples thereof include, but are not limited to, anhydrides of polyunsaturated acids, esters of these polyunsaturated acids, aromatic vinyl compounds, unsaturated nitriles, and the like. These other monomers may be used alone or in combination of two or more. In the case of a vinyl chloride copolymer, the content of other monomers in the copolymer is 30% by weight or less, preferably 20% by weight or less.

In the polymerization reaction of the present invention, as a polymerization initiator, for example, persulfates (sodium salt, potassium salt, ammonium salt, etc.), water-soluble peroxides such as hydrogen peroxide, these initiator compounds and sodium sulfite, Ammonium sulfite, sodium bisulfite, ascorbic acid, water-soluble redox initiators consisting of reducing agents such as formaldehyde sodium sulfoxylate, azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, lauroyl peroxide, Monomer-soluble (oil-soluble) initiators such as t-butyl peroxybivalate, and initiators comprising a combination of these monomer-soluble initiator compounds and the above reducing agent for the redox initiator Can be given.

Depending on the type of these initiators, they may adversely affect the thermal stability, water whitening property, paste viscosity and the like, so it is necessary to pay sufficient attention to the selection of the type and the amount used. Generally speaking, organic initiators and inorganic ammonium salt initiators often give good results.

Examples of the emulsifier used in the polymerization reaction of the present invention include higher alcohol sulfuric acid ester alkali metal or ammonium salts, alkylbenzene sulfonate alkali metal or ammonium salts, and the like. These emulsifiers may be used alone or in combination of two or more. Used. In particular, when a polymer composition having improved water whitening property and thermal stability is desired, a fatty acid emulsifier is used as a main emulsifier, and the total alkali metal content in the obtained polymer is 500 ppm or less. The higher fatty acid ammonium salt is most preferable in terms of the balance of physical properties. In this case, the higher fatty acid preferably has 8 to 18 carbon atoms. The amount of the emulsifier used is 0.1 to 3.0 parts by weight, preferably 0.3 to 1.0 part by weight, based on 100 parts by weight of the charged monomer such as vinyl chloride.

The hydrotalcites used in the present invention are BET
Those having a specific surface area of 30 m ² / g or less and having been subjected to decrystallization water treatment are preferable. The amount of hydrotalcites added is 0.1 to 5.0 parts by weight, preferably 0.15 parts by weight per 100 parts by weight of the charged monomers.
~ 3.0 parts by weight. If the amount of hydrotalcites added is small, the effect of improving thermal stability is insufficient, and if too large, the transparency of the product may be reduced.

The addition of the aqueous slurry of hydrotalcites in the present invention can be performed before the initiation of polymerization, during the polymerization, or at any time after the completion of the polymerization reaction. For example, it may be added at the time of charging water or a monomer before the start of polymerization or before or after the addition, or at the same time as or before or after the addition of an emulsifier, a polymerization initiator, a polymerization aid, or the like. However, it may be added at any time during the polymerization reaction, or may be added to the produced latex at any time after the completion of the polymerization reaction and before the drying step. The addition may be batch addition, divided addition, or continuous addition.

Further, the method of dispersing hydrotalcites in deionized water in the present invention to prepare a slurry thereof can be easily carried out by adding powder of hydrotalcites to deionized water and stirring. However, of course, other slurry forming methods can be adopted.
In addition, it is also possible to use an appropriate amount of a surfactant in order to improve the "familiarity" of hydrotalcites with water when making it into a slurry, as long as it does not affect the water-absorption whitening property and thermal stability. It is possible within.

The greatest feature of the production method of the present invention is that hydrotalcites are dispersed in deionized water in a slurry state and added. Deionized water is water that has been deionized using an ion exchange resin or the like, and is also called ion exchange water.

The inventors of the present invention add the hydrotalcites previously prepared in a water slurry or emulsion in the examples of the above-mentioned Japanese Patent Application No. 62-231594 (JP-A-1-74203). Suggests an invention. However, the water used to make the hydrotalcites in the water slurry or emulsion in this example is not deionized water, so the effect of improving the water-absorption whitening property is not sufficient, and an emulsion was prepared. The addition method has a drawback that the manufacturing operation becomes more complicated. On the other hand, in the present invention, by simply adding the hydrotalcites to an aqueous slurry using deionized water and adding the hydrotalcites, it is possible to obtain an excellent effect of improving the water-absorption whitening property and the thermal stability. Then, in the method of the present invention, even if hydrotalcites slurried using industrial water such as ground water or tap water instead of the deionized water is added, a sufficient effect of improving the water-absorption whitening property can be obtained. It does not exist (see Comparative Example 1 and Comparative Example 3).

In the method for producing a vinyl chloride polymer composition for a paste dispersion of the present invention, various auxiliaries commonly used in the production of a vinyl chloride polymer for a paste are optionally added during the production process. A substance or the like can be added. However, among these types of auxiliaries and modifiers, there are many that adversely affect the thermal stability, water whitening property, paste viscosity, etc., so care must be taken in selecting the type. The amount added should be kept to the minimum necessary.

Then, in order to obtain a polymer composition which gives a low-viscosity paste while preventing adverse effects on heat stability and water absorption whitening property, the present inventors have emulsifiers according to the invention [JP-A-63-172769].
And Japanese Patent Application No. 62-101790 (JP-A-63-26)
8755)) is particularly effective.

The vinyl chloride-based polymer composition for a paste dispersion obtained by the production method of the present invention is a vinyl chloride-based polymer paste dispersion composition (plastisol or organosol if added with an organic liquid such as a plasticizer or a diluent). Etc.),
At that time, if necessary, stabilizers and other compounding agents (for example, antioxidants, ultraviolet absorbers, fillers, antistatic agents, coloring agents, release agents, etc.) can be compounded.

Examples of the plasticizer include di-n-butyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, diisononyl phthalate, diisodecyl phthalate, octyldecyl phthalate, and phthalic acid. Butylbenzyl, di-2-ethylhexyl isophthalate, phthalate ester-based plasticizers such as phthalate esters of higher alcohols having about 11 to 13 carbon atoms, di-n-octyl-n-decyl trimellitate, and trimellitate trimester. Trimellitic acid ester plasticizers such as 2-ethylhexyl, triisodecyl trimellitate and tri-n-octyl trimellitate, di-2-ethylhexyl adipate, di-n-decyl adipate, diisodecyl adipate, azelaic acid Di-2-ethylhexyl, dibutyl sebacate, seba Fatty acid ester-based plasticizers such as cy-2-ethylhexyl silicate, tributyl phosphate, tri-2-ethylhexyl phosphate, 2-ethylhexyl diphenyl phosphate, tricresyl phosphate-based ester plasticizers, large epoxidation Epoxy plasticizers such as soybean oil, epoxidized linseed oil, epoxidized tall oil fatty acid-2-ethylhexyl, liquid epoxy resins and the like can be mentioned.
These plasticizers may be used alone or in combination of two or more.

As the stabilizer, those for vinyl chloride-based resin stabilizers can be used, but liquid composite stabilizers and organic tin-based stabilizers give particularly good results.

In this case, the "composite stabilizer" is a salt of at least two kinds of organic acids of metals (for example, ricinoleic acid, 2-ethylhexoic acid, naphthenic acid, benzoic acid, salicylic acid, etc.), which are usually commercially available in liquid form. Has been done. Among these, in the case of a sol using the polymer composition of the present invention, barium-zinc type, calcium-zinc type, magnesium-zinc type, calcium-barium type, cadmium-
Particularly preferred are barium, barium-zinc-tin, and cadmium-barium-zinc.

Examples of organic tin stabilizers include dibutyltin dilaurate, dibutyltin malate, dibutyltin mercaptide and the like.

The amount of these stabilizers used is 0.1 to 5.0 with respect to 100 parts by weight of the vinyl chloride polymer in the vinyl chloride polymer composition.
Parts by weight, preferably 0.15 to 3.0 parts by weight. If the proportion used is too small, the thermal stability of the product will deteriorate, and if it is too large, the whitening property with water absorption will deteriorate.

[Examples, etc.]

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to the examples. In addition,
The “parts” and “%” described in these examples are based on weight.

Moreover, the following formulations were used as the formulations of plastisol in the tests described in these examples.

Vinyl chloride polymer composition 70 parts Blending resin * 1 30 parts Di-2-ethylhexyl phthalate 50 parts Ba-Zn stabilizer * 2 3 parts Epoxy stabilizer * 3 2 parts Note) * 1 ... Vinika 75BX (registered trademark of Mitsubishi Kasei Vinyl Co., Ltd.) * 2 ... AC-118 (trade name of ADEKA ARGUS CHEMICAL CO., LTD.) * 3 ... FEP-13 (trade name of ADEKA ARGUS CHEMICAL CO., LTD.) The thermal stability test was as follows.

Water Absorption Whitening Test Using each polymer composition (polymer) produced in each Example and Comparative Example, each plastisol obtained by the above plastisol blending, a glass plate having a thickness of 1 mm after heating. The sheet was applied on the surface, gelled and melted at 200 ℃ for 5 minutes, cut out, and pressed at 30 ℃ / cm ² for 5 minutes at 160 ℃ to a thickness of 0.35mm.
Immerse in warm water at ℃, take out every predetermined time, transmit the light of wavelength 550nm using a spectrophotometer, measure the amount of transmitted light, calculate the light transmittance (%), and absorb the value Use it as a measure of whiteness.

Thermal stability test Each of the same plastisols used in the water absorption whitening test on an aluminum foil, the sheet thickness after heating 1m
m so that the coating film is heat-treated at 195 ° C. for 5 minutes and then cut out, and the cut out sheet is continued to 195
After heating for 5 minutes, 8 minutes, and 10 minutes each, the sample is taken out every 1 minute thereafter, and the time until coloring red to (black) brown is visually inspected to determine the thermal stability. Use as a guide.

Example 1 A polymerization tank having a volume of 200, equipped with a stirrer, was heated at a temperature of
C. deionized water, 12 g ammonium persulfate, and 75 g ammonium sulfite were added and stirred for about 20 minutes to dissolve. Then, reduce the pressure in the polymerization tank to -610 mmHg, and
Hold at 4 ° C.

Next, 60 kg of vinyl chloride monomer was charged into this polymerization tank, and the temperature inside the tank was raised to 50 ° C. 15 minutes after charging the monomer, gradually add 0.2% ammonium persulfate aqueous solution dissolved in advance at a rate of about 10 cc / min, and then add ammonium persulfate aqueous solution so as to keep a constant polymerization rate. The reaction was performed while controlling the speed. When the rate of polymerization reached about 15%, start adding about 10% aqueous solution of ammonium myristate that had been separately dissolved, and add 80 cc / 1 of this aqueous solution.
The total amount of ammonium myristate added was 3 at a speed of around 0 minutes.
Added to 60 g. The reaction was stopped when the pressure in the tank was reduced to 2.0 kg / cm ² from the saturation pressure of the vinyl chloride monomer at 50 ° C., and the unreacted monomer was recovered to obtain a polymer latex.

The obtained latex was a single dispersion particle having a particle size of about 0.44μ, and the stability of the latex was good.

In a polymerization tank with a volume of 200 equipped with a stirrer, the latex obtained as above was used as a seed latex of 4.5 kg.
(In terms of solid content), deionized water 80 kg, hydrotalcite deionized water 10% water slurry 10 kg, and ammonium sulfite 90 g were charged respectively, and after degassing, charged with vinyl chloride monomer 75.5 kg, The temperature was raised to 50 ° C. Then, a total amount of 15 g of a 0.1% aqueous solution of ammonium persulfate 10 was initially added at a rate of 10 cc / min for about 15 minutes, and then,
The addition rate was controlled so as to maintain a constant polymerization rate, and the addition was continuously performed. From when the polymerization rate reached about 10%, add about 10% aqueous solution of ammonium myristate to about 0.7 /
A total of 0.5 kg of myristic acid was continuously added at the rate of hr. From the saturation pressure of vinyl chloride monomer at 50 ℃ in the tank
The polymerization was stopped when 1.0 kg / cm ^{2 was} dropped, and unreacted monomers were recovered.

The average particle size of the obtained latex was 1.0 μm. This latex was spray-dried and pulverized according to a conventional method to obtain a vinyl chloride polymer composition.

Comparative Example 1 Comparative Example 2 An aqueous slurry of hydrotalcite was prepared using industrial water (ground water), otherwise the reaction was carried out in the same manner as in Example 1, followed by dry pulverization to obtain a vinyl chloride polymer composition. (Comparative example 1).

Further, the reaction was carried out in the same manner as in Example 1 except that hydrotalcite was not used, and the mixture was dried and pulverized to obtain a vinyl chloride polymer (Comparative Example 2).

Example 2 Comparative Example 3 To the vinyl chloride polymer latex obtained in Comparative Example 2 was added 12 kg of a water slurry (concentration 10%) of deionized water of hydrotalcite before drying (Example 2), or Same as before drying polyvinyl chloride latex, water slurry of tap water of hydrotalcite (concentration 10
%) Was added (Comparative Example 3), and thereafter, each vinyl chloride polymer composition was prepared by spray drying and pulverizing in accordance with a conventional method.

Example 3 Comparative Example 4 100 k of deionized water in 200 premixing tanks equipped with stirrer
g, lauroyl peroxide 600 g, sodium lauryl sulfate 400 g, and lauryl alcohol 200 g were added, and then the premixing tank was degassed, vinyl chloride monomer 60 kg was added, and the mixture was maintained at 35 ° C. with stirring. After uniform stirring, the mixture was transferred to a 200-volume reaction tank equipped with a stirrer that had been degassed in advance while further dispersing the droplet size to 0.4 to 0.5 μ using an emulsifier. After the completion of the transfer, the temperature inside the reaction tank was raised to 47 ° C. and polymerization was performed. The average diameter of the polymer particles in the obtained latex was 0.46μ. Polymerization was carried out using this latex as a seed polymer latex.

That is, 80 kg of deionized water, 6 kg of the seed polymer latex (as solid content), and 20 kg of sodium hydrogen carbonate were charged in a polymerization tank having a volume of 200 and equipped with a stirrer, and then deaerated, and then vinyl chloride monomer was added. After 74 kg was charged and the temperature was raised to 47 ° C., a 0.3% aqueous solution of sodium pyrosulfite previously dissolved was continuously added little by little to the polymerization tank to start the polymerization. The amount of sodium pyrosulfite aqueous solution added was adjusted to obtain a constant reaction rate. About 10% of ammonium laurate prepared separately as an emulsifier from the time the polymerization rate reached 10% to the end of the polymerization.
% Aqueous solution (total 0.4 kg of lauric acid) was continuously added at a rate of 1000 cc per hour. When the pressure in the polymerization tank dropped by 1.5 kg / cm ² from the saturated pressure of vinyl chloride at 47 ° C, the polymerization was stopped, and an aqueous slurry (concentration 10%) prepared by deionized water of hydrotalcite was prepared in advance. After press-fitting 7 kg, unreacted monomer was recovered.

The obtained latex had an average particle size of 1.0 μ, and the stability of the latex was good. This latex was spray-dried and then pulverized to obtain a vinyl chloride polymer composition (Example 3).

Further, a vinyl chloride polymer composition was obtained in the same manner as in Example 3 except that industrial water (ground water) was used for slurrying hydrotalcite (Comparative Example 4).

Using the vinyl chloride polymer compositions (polymers) obtained in Examples 1 to 3 and Comparative Examples 1 to 4 described above, each plastisol was prepared according to the above-mentioned formulation, and each plastisol obtained was used. A water absorption whitening test and a thermal stability test were carried out by the above test method.

Comparative Example 5 The following experiment was conducted in order to evaluate the case where hydrotalcite was added as a powder at the time of compounding instead of the method of the present invention.

69 parts of the dry vinyl chloride polymer obtained in Comparative Example 2, 30 parts of blending resin, 1 part of powdered hydrotalcite (Alkamizer II, manufactured by Kyowa Chemical Co., Ltd.), 50 parts of di-2-ethylhexyl phthalate. , 3 parts of Ba-Zn stabilizer,
And 2 parts of the epoxy-based stabilizer were mixed and dispersed to prepare a plastisol. All the compounds other than the vinyl chloride polymer and powdered hydrotalcite were the same as those in the other examples.

Using this plastisol, a water absorption whitening test and a thermal stability test were conducted in the same manner as described above.

The results of the above tests are shown in Table 1. Also, the attached drawings are graphs showing the results of the water-absorption whitening test shown in Table 1 (excluding the results of Comparative Example 5). As is clear from Table 1 and the accompanying drawings, the sheet obtained from the plastisol using the polymer composition obtained in each example is more than the sheet obtained from the plastisol using the polymer (composition) obtained in the comparative example. Compared with the obtained sheet, it is remarkably excellent in water absorption whitening property and also has good thermal stability.

(C) Effect of the Invention The vinyl chloride-based polymer composition for a paste dispersion obtained by the production method of the present invention is remarkably improved in water absorption whitening property,
Further, since it can be used as a vinyl chloride polymer paste dispersion which gives a product having good thermal stability, it is advantageously used particularly for producing transparent products such as floor surface layers.

[Brief description of drawings]

The accompanying drawings are graphs showing the results of water-absorption whitening test of gelled coatings of plastisol using the vinyl chloride polymer compositions obtained in Examples and Comparative Examples (excluding Comparative Example 5).

Claims (1)

(57) [Claims] 1. A vinyl chloride polymer capable of forming a paste obtained by emulsion polymerization or fine suspension polymerization of vinyl chloride alone or a mixture of vinyl chloride and another monomer copolymerizable with vinyl chloride, and hydrotal. In the method for producing a vinyl chloride-based polymer composition for a paste dispersion containing sites, as the means for containing the hydrotalcites, before the initiation of the polymerization, during the polymerization or at any time after the completion of the polymerization reaction. A method for producing a vinyl chloride-based polymer composition for a paste dispersion, characterized in that a method of adding hydrotalcites in the form of an aqueous slurry in which deionized water is dispersed is used.