JPH09100379A - Paste vinyl chloride resin and preparation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a paste vinyl chloride resin which can offer a foam having high whiteness and possesses excellent long-term storage stability, sol-forming property, and foamability by specifying the contents of predetermined compds. in a paste vinyl chloride resin prepd. by using a salt of an alkylbenzenesulfonic acid as a polymn. emulsifier. SOLUTION: The content of a compd. represented by the formula (wherein M represents an alkali metal or ammonium; and R1 and R2 represent a 1-8C straight-chain aliph. hydrocarbon group) is regulated to less than 500ppm. This can be achieved by using a salt of an alkylbenzenesulfonic acid having a content of the compd. of the formula of less than 6wt.%, pref. less than 3wt.%, as a polymn. emulsifier in an amt. of 0.5 to 2.0 pts.wt. based on 100 pts.wt. vinyl chloride monomer. The content of the compd. of the formula in the salt of the alkylbenzenesulfonic acid can be reduced by purification of an alkylbenzene as a raw material by distillation under reduced pressure to reduce the amount of a dialkyltetrazone as an impurity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a paste vinyl chloride resin. More specifically, when foaming the paste vinyl chloride resin, the whiteness is high, the foamability and the sol-forming property are excellent, and the change over time is suppressed so that a foam having always stable whiteness can be obtained. And a method for producing the same.

[0002]

2. Description of the Related Art A paste vinyl chloride resin (hereinafter abbreviated as paste vinyl chloride) is kneaded with a compounding agent such as a plasticizer, a stabilizer, a foaming agent, and the like to be processed as a paste vinyl chloride sol for various processing. Various molded products can be obtained depending on the processing method. Among them, building materials such as wallpaper and floor materials are one of the main uses of paste PVC. And, this foam molded product has various tones, and the foam before toning is easy to adjust the color, or the users who use the foam molded product prefer white products. A high degree of foam is desired.

The paste vinyl chloride is a vinyl chloride monomer alone or a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable with the vinyl chloride monomer (hereinafter referred to as vinyl chloride-based monomer). Body) is produced by polymerizing, generally, an emulsion polymerization method using an emulsifier and a water-soluble initiator, or
In the presence of an emulsifier, a dispersing aid such as higher alcohols, and an oil-soluble initiator, homogenization treatment is performed, and then paste vinyl chloride latex is produced by a fine suspension polymerization method in which polymerization is performed with gentle stirring, and this is sprayed. Obtained by drying.

Since the paste vinyl chloride is produced by the above-mentioned method, the paste vinyl chloride contains a lot of additives such as emulsifiers and modifiers used for the polymerization in addition to the vinyl chloride resin component. The additives and the like contained in these paste vinyl chlorides greatly affect the sol physical properties of the paste vinyl chloride typified by viscosity and the physical properties and finish of the molded product.

Alkyl sulfate, alkylbenzene sulfonate (hereinafter abbreviated as ABS) and the like are generally used as emulsifiers used in the production of paste vinyl chloride.

[0006]

However, the paste vinyl chloride produced by using an alkyl sulfate as an emulsifier is
There is a problem that the sol-forming property or the foaming property is inferior such that the viscosity becomes high at the time of producing the paste vinyl sol, and the high filling cannot be supported.

Therefore, it has a dense cell structure capable of coping with high foaming at the time of high filling and reduction of the organic solvent at the time of compounding, cost reduction by obtaining a paste viscosol having a low viscosity. In recent years, paste PVC using ABS as an emulsifier for polymerization has become mainstream because a foam can be easily obtained. However, the paste polyvinyl chloride obtained by using ABS as an emulsifying agent for polymerization is inferior in whiteness of the foam compared to the case where an alkyl sulfate ester is used as an emulsifying agent for polymerization, and it is stored for a long period of time or exposed to high temperature or direct irradiation. Foams obtained by using paste PVC after storage in an environment exposed to sunlight have problems such as significantly reduced whiteness compared to foams using paste PVC immediately after production. Was there.

An object of the present invention is to provide a paste vinyl chloride having a high whiteness when a foam is manufactured, and having excellent long-term storage stability, sol-forming property and foaming property, and a method for manufacturing the same.

[0009]

Means for Solving the Problems The inventors of the present invention have obtained a foam having a high whiteness, long-term storage stability, sol-forming property,
As a result of intensive studies on paste PVC having excellent foaming properties, the inventors have found that a specific compound contained in the paste PVC is a cause of deterioration in whiteness and long-term storage stability, and arrived at the present invention.

That is, the present invention uses AB as an emulsifying agent for polymerization.
The present invention relates to a paste vinyl chloride produced using S, in which the content of the compound represented by the following general formula (I) is less than 500 ppm, and a method for producing the paste vinyl chloride.

[0011]

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(However, M represents one selected from alkali metal or ammonium groups, and R ₁ and R ₂ each represent a linear aliphatic hydrocarbon group having 1 to 8 carbon atoms. The present invention will be described in detail below.

The paste vinyl chloride of the present invention is a paste vinyl chloride produced by using ABS as an emulsifier for polymerization.
The content of the dialkyltetraline sulfonate represented by the general formula (I) (hereinafter abbreviated as DATS) is 5
It is a paste vinyl chloride that is less than 00 ppm. DATS
It has been found by the study of the present inventors that the cause of deterioration of whiteness and long-term storage stability of the paste PVC is
The paste PVC containing 500 ppm or more of TS is
It is not preferable because the whiteness of the foam produced is low and the long-term storage stability is poor.

Even if it is contained in the paste PVC of the present invention in an amount of less than 500 ppm, the DATS represented by the above general formula (I) with which the object of the present invention is achieved is selected as M from alkali metal or ammonium groups. R ₁ and R ₂ are each a linear aliphatic hydrocarbon group having 1 to 8 carbon atoms. As M, lithium, potassium,
Examples thereof include sodium, rubidium and cesium. Examples of R and R'include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and an octyl group. If the amount of these DATS contained in the paste vinyl chloride is less than 500 ppm,
It may exist as a mixture of two or more kinds.

As the method for producing the paste vinyl chloride of the present invention, any production method can be used as long as it is possible to obtain the paste vinyl chloride of the present invention. Emulsion polymerization method in which the monomer is deionized water, ABS as an emulsifying agent for polymerization, a water-soluble polymerization initiator and polymerization with gentle stirring, and a seed emulsion weight for performing emulsion polymerization using particles obtained by the emulsion polymerization method as seeds Legitimate, after mixing vinyl chloride monomer with deionized water, emulsifier, emulsification aid such as higher alcohol, if necessary, oil-soluble polymerization initiator with homogenizer, etc., and then polymerizing under gentle stirring. At a polymerization temperature of 30 to 80 ° C., a seed microsuspension polymerization method in which a seed containing an oil-soluble polymerization initiator obtained by the suspension polymerization method or the microsuspension polymerization method is used for polymerization is used. And, after spray drying the resulting latex can be mentioned a method of manufacturing a paste PVC by grinding.

When producing the paste vinyl chloride of the present invention,
ABS, which is represented by the following general formula (II), is used as an emulsifier for polymerization because a paste vinyl chloride having excellent sol-forming property and foaming property can be obtained.

[0017]

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(Wherein M represents one selected from alkali metal or ammonium groups, R ₃ represents hydrogen or a linear aliphatic hydrocarbon group having 1 to 12 carbon atoms, R _{3 4} represents a linear aliphatic hydrocarbon group having 1 to 12 carbon atoms.) ABS, which is an emulsifier for polymerization represented by the above general formula (II) and used in producing the paste vinyl chloride of the present invention, is M
As an alkali metal or an ammonium group, R ₃ is hydrogen or a linear aliphatic hydrocarbon group having 1 to 12 carbon atoms, and R ₄ is 1 to 12 carbon atoms.
Is a linear aliphatic hydrocarbon group. Examples of M include lithium, potassium, sodium, rubidium, and cesium. When R and R ′ are linear aliphatic hydrocarbon groups having 1 to 12 carbon atoms, such groups include methyl group, ethyl group, propyl group, butyl group,
Examples thereof include a pentyl group, a hexyl group, an octyl group and a dodecyl group. Further, these ABS may be used as a mixture of two or more kinds in the production of paste PVC.

Further, the ABS used for producing the paste vinyl chloride of the present invention has high whiteness when the foam is produced, and the paste vinyl chloride excellent in long-term storage property, sol-forming property and foaming property is shown above. Since it can be easily obtained by the conventional method for producing paste PVC, DAT in ABS is used.
It is preferable that the S content is less than 6% by weight, particularly less than 3% by weight.

Further, generally available ABS is D
It contains 10 to 20% by weight of ATS. Such an A
When BS is used, it is difficult to produce the paste vinyl chloride of the present invention only by the above production method, but by adding a process such as refining the obtained paste vinyl chloride latex, It is possible to produce paste PVC.

In order to easily produce the paste vinyl chloride of the present invention by the above-mentioned production method, a method of reducing the DATS content in ABS used as an emulsifying agent for polymerization is
For example, it can be achieved by any method such as vacuum distillation, steam distillation, extraction and column separation. Further, as a result of the study, it was clarified that dialkyltetralin, which is the basic skeleton of DATS, is present as an impurity in the alkylbenzene, which is a raw material of ABS, as a cause of contamination. Therefore, it is possible to efficiently produce ABS having a low DATS content by purifying the alkylbenzene as a raw material by any of the methods described above to reduce dialkyltetralin and then sulfonation.

ABS used as an emulsifying agent for polymerization when producing the paste vinyl chloride of the present invention is excellent in stability during polymerization, and the viscosity increase when the obtained paste vinyl chloride is solized is low, so vinyl chloride is used. It is preferable to use 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the system monomer.

The vinyl chloride-based monomer used in producing the paste vinyl chloride of the present invention is a vinyl chloride monomer alone,
Alternatively, it is a mixture of a vinyl chloride monomer and a vinyl monomer copolymerizable with the vinyl chloride monomer. Examples of vinyl monomers that can be copolymerized with vinyl chloride monomers include vinyl acetate, vinyl propionate, vinyl myristate,
Vinyl esters such as vinyl benzoate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid or anhydrides; esters of acrylic acid methyl, ethyl, butyl, etc., methyl methacrylate, methacrylic acid , Esters such as butyl, unsaturated carboxylic acid esters such as maleic acid ester, fumaric acid ester, cinnamic acid ester; vinyl ethers such as vinyl methyl ether, vinyl amyl ether, vinyl phenyl ether; ethylene, propylene, butene, pentene Examples thereof include monoolefins such as vinylidene chloride, styrene and its derivatives, acrylonitrile, methacrylonitrile, and other ordinary vinyl compounds that can be radically copolymerized with vinyl chloride, and two or more of these can be used.

The emulsifier for polymerization used in the production of the paste vinyl chloride of the present invention may be an alkyl benzene sulfonate, which is the main emulsifier for polymerization, and other emulsifiers as long as they do not affect the whiteness and long-term storage stability of the foam. Can be used together.
Specific examples of emulsifiers that can be used in combination include fatty acid salts such as lauryl sulfate and sodium myristyl sulfate; sorbitan esters such as sorbitan monooleate and polyoxyethylene sorbitan monostearate; nonionics such as polyoxyethylene alkylphenyl ether. Examples include system emulsifiers.

Examples of emulsification aids used as necessary include higher alcohols such as lauryl alcohol and cetyl alcohol; higher fatty acids such as lauric acid and palmitic acid, and esters thereof.

[0026]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Synthesis Example 1 (Production of Purified Sodium Alkylbenzene Sulfonate) In a 1-liter Claisen type flask equipped with a fractionating tube, 500 g of alkylbenzene mainly containing alkylbenzene (dodecylbenzene) having an alkyl chain length of 12 was placed and 1 mm.
The pressure was reduced to Hg with a vacuum pump. Next, heat the Claisen flask in an oil bath at about 80 ° C to 60 to 65 ° C.
Was collected as a distillate to purify the alkylbenzene under reduced pressure.

101 g of sulfuric acid was added to 300 g of alkylbenzene obtained by distillation purification, and sulfonation was carried out in a flask at 30 ° C. with stirring. afterwards,
46 g of sodium hydroxide and 405 g of deionized water are added,
By neutralizing, sodium alkylbenzenesulfonate having a pure content of about 48.5% (hereinafter abbreviated as ABS1) was obtained.

The DATS content in the obtained ABS1 was determined by ion exchange chromatography.
It was 8% by weight.

Synthesis Example 2 (Production of Crude Sodium Alkylbenzene Sulfonate) Synthesis of sodium alkylbenzene sulfonate (hereinafter abbreviated as ABS2) is carried out in the same manner as in Synthesis Example 1 except that distillation and purification of alkylbenzene is not carried out under reduced pressure. I went.

The content of DATS in the obtained ABS2 was determined by ion exchange chromatography to be 1
It was 1.4% by weight.

Example 1 In a 2.5 l stainless steel autoclave, 1200 g of deionized water, 800 g of vinyl chloride monomer, 0.64 g of lauroyl peroxide as a polymerization initiator, 8.1 g of ABS1 as an emulsifying agent for polymerization, and emulsification 12 g of lauryl alcohol was charged as an auxiliary agent, the polymerization solution was homogenized for 75 minutes using a homogenizer, and then the temperature was raised to 64 ° C. to initiate polymerization. The polymerization reaction was stopped when the polymerization pressure dropped 5 kg / cm ² from the saturated vapor pressure of vinyl chloride at 64 ° C. Then, collect the unreacted vinyl chloride monomer,
A vinyl chloride polymer latex was obtained. The obtained latex was spray-dried with a spray dryer at a hot air inlet of 190 ° C and an outlet temperature of 63 ° C. Then, it crushed and the paste vinyl chloride was collect | recovered.

The amount of DATS in the paste PVC is 193 p.
pm.

The obtained paste PVC is paste PVC 1
To 00 parts, 50 parts of dioctyl phthalate as a plasticizer, 55 parts of CaCO _3, 5 parts of stabilizer (manufactured by Kyodo Chemical Co., Ltd., trade name KF65-J2), 5 parts of foaming agent (manufactured by Eiwa Kasei, trade name AC1C), After adjusting the sol by mixing 15 parts of pigment (titanium toner) and 5 parts of diluent (mineral spirit),
Foaming was performed under the following processing conditions and the foaming hue was measured. Further, the foam cell structure was visually evaluated. The results are shown in Table 1-Foam processing conditions-The paste PVC sol prepared by the above formulation is coated on flame-retardant paper to a thickness of 0.25 mm and heated in an oven heated to 140 ° C for 40 seconds. As a result, a semi-gel sheet was prepared. The sheet was cooled to room temperature and then heated in an oven heated to 210 ° C. for 60 seconds to obtain a foam.

-Measurement of Foamed Hue- The yellow index value (YI) was measured with a color difference meter (Nippon Denshoku, trade name MODEL-9463).

YI is an index showing yellowishness, and the smaller the value of YI, the whiter the foam is.

If the difference in YI value is 0.5 or more, it is possible to judge the difference in foaming hue change by visual observation.

-Foam Cell Structure- The foam cell structure was visually evaluated.

(◯): Dense cell (×): Rough cell Example 2 Synthesis of paste polyvinyl chloride was carried out in the same manner as in Example 1 except that the charged amount of ABS1 which was an emulsifying agent for polymerization was 6.5 g. And evaluated. Table 1 shows the evaluation results.

Example 3 A paste vinyl chloride was synthesized and evaluated in the same manner as in Example 1 except that the charged amount of the emulsifying agent ABS1 was 12.2 g. Table 1 shows the evaluation results.

Comparative Example 1 Paste vinyl chloride was synthesized and evaluated in the same manner as in Example 1 except that the polymerization emulsifying agent was ABS2 and the charged amount was 8.1 g. Table 1 shows the evaluation results.

The foam produced from the obtained paste vinyl chloride had a low degree of whiteness, and the degree of whiteness was greatly reduced when processed after long-term storage.

Comparative Example 2 Synthesis and evaluation of paste vinyl chloride was carried out in the same manner as in Example 1 except that ABS2 was used as the emulsifying agent for polymerization and the charged amount was 6.5 g. Table 1 shows the evaluation results.

The foam produced from the obtained paste vinyl chloride had a low whiteness, and the whiteness was greatly reduced when processed after long-term storage.

Comparative Example 3 The emulsifying agent for polymerization was ABS2, and the charged amount was 12.2 g.
Paste vinyl chloride was synthesized and evaluated by the same method as in Example 1 except for the above. Table 1 shows the evaluation results.

The foam produced from the obtained paste vinyl chloride had a low whiteness, and the whiteness was greatly reduced when processed after long-term storage.

Comparative Example 4 ABS1 was used as a polymerization emulsifier, and the charged amount was 24.8 g.
Paste vinyl chloride was synthesized and evaluated by the same method as in Example 1 except for the above. Table 1 shows the evaluation results.

The foam produced from the obtained paste vinyl chloride had a low whiteness, and the whiteness was greatly reduced when processed after long-term storage.

Comparative Example 5 Sodium lauryl sulfate (hereinafter referred to as S) as an emulsifying agent for polymerization.
Abbreviated as LS. ) Was used, and paste vinyl chloride was synthesized and evaluated in the same manner as in Example. Table 1 shows the evaluation results.

Regarding the foamed cell structure of the obtained foam, the paste polyvinyl chloride sol obtained because the cells were coarse had a high viscosity and inferior foamability.

[0051]

[Table 1]

[0052]

INDUSTRIAL APPLICABILITY The paste vinyl chloride obtained according to the present invention has a high whiteness when a foam is produced and is excellent in long-term storage property, sol-forming property and foaming property, and therefore has an extremely high industrial value. Is.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Tadashi Okada 1-7-2 Tomita, Shinnanyo-shi, Yamaguchi Prefecture

Claims (2)

[Claims] 1. A paste vinyl chloride resin produced by using an alkylbenzene sulfonate as an emulsifier for polymerization, wherein the content of the compound represented by the following general formula (I) is less than 500 ppm. Embedded image (However, M represents one selected from alkali metal or ammonium groups, and R ₁ and R ₂ are each a carbon number of 1 to 1.
Represents eight linear aliphatic hydrocarbon groups. ) 2. A method for producing a paste vinyl chloride resin, wherein the addition amount of alkylbenzene sulfonate is
0.5 to 2.0 parts by weight based on 100 parts by weight of vinyl chloride monomer alone or a mixture of vinyl chloride monomer and vinyl monomer copolymerizable with vinyl chloride monomer. The method for producing the paste vinyl chloride resin according to claim 1, characterized in that.