JP3286675B2 - Method for producing polyvinyl chloride resin for paste processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyvinyl chloride resin for paste processing, which is improved by a seed microsuspension polymerization method. More specifically, in the production of polyvinyl chloride resin for paste processing by seed microsuspension polymerization, the generation of microparticles during polymerization is suppressed, the viscosity is low, the viscosity does not change with time, and the gelation and melting properties are excellent. The present invention relates to a method for producing a polyvinyl chloride resin for paste processing, which gives a paste salt visol.

[0002]

2. Description of the Related Art Generally, a method for producing polyvinyl chloride for paste processing (hereinafter abbreviated as "paste PVC") is a method of preparing a polyvinyl chloride monomer or a vinyl monomer copolymerizable therewith in an aqueous medium. Polymerization is performed while stirring at a predetermined temperature in the presence of an activator and a polymerization initiator, and the obtained polymer latex is spray-dried. The dried resin may be used as it is, or may be pulverized to an appropriate size as needed, or subjected to a granulation treatment, or the like. The obtained paste PVC is used for processing as a paste PVC sol by kneading with a compounding agent such as a plasticizer, a stabilizer and a diluent.

[0003] The paste salt visol obtained as described above is processed by a method such as a coating method, a slush molding, an immersion molding, and a rotational molding to obtain a molded product. At that time, if the sol viscosity at the time of processing is high or the rate of gelation and melting is low, for example, the processing speed at the time of coating cannot be increased, affecting productivity, or a uniform molded product cannot be obtained, or In addition, there is a problem that processing is difficult due to a large change in viscosity over time.

[0004] These problems in the paste PVC sol are considered to be caused by the basic particle size of the paste PVC.

[0005] The seed micro-suspension polymerization method is used in the order of 0.5 μm
The seed particles containing the oil-soluble polymerization initiator are used alone or, if necessary, by using seed particles not containing the oil-soluble polymerization initiator, and growing the seed particles to about 0.1 μm to 2 μm.
This is a production method peculiar to paste PVC, which obtains particles of about m. When seed microsuspension polymerization is carried out using commonly used anionic and nonionic surfactants,
Many fine particles smaller than 0.1 μm other than the seed particles are mainly generated at the end of polymerization.

[0006] The large number of particles of less than 0.1 µm generated when the polymer latex is dried to obtain paste PVC,
When the paste salt visol is used to increase the cohesion between particles of 0.1 μm to 2 μm, the viscosity increases due to the deterioration of dispersibility in liquid components such as a plasticizer, and the porosity of the aggregates is increased. It is considered that the change of the sol with the passage of time is increased due to the absorption of the liquid component into the acidic part.

Various methods have been tried for the purpose of obtaining a sol having a low viscosity and a small change in viscosity over time. As an example, a method in which an alkali metal salt or ammonium salt of polyoxyethylene alkylphenol ether sulfate is used in microsuspension polymerization (JP-B-63-35)
166), a method of using an alkali metal salt or ammonium salt of polyoxyethylene alkylphenyl ether sulfonate in emulsion polymerization or microsuspension polymerization (Japanese Patent Application Laid-Open No. 61-44907), and the like. In particular, there is no solution by suppressing fine particles generated during the polymerization.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies on a method for producing a paste PVC having a low viscosity, a small change in viscosity over time, and an excellent gelation and melting property. As a result, the following general formula [I] was obtained. The present inventors have found that a paste PVC sufficiently satisfying the above-mentioned requirements can be obtained by performing seed microsuspension polymerization using the surfactant shown, and have reached the present invention.

[0009]

That is, the present invention relates to a method for preparing a vinyl chloride monomer alone or a vinyl chloride monomer and a vinyl monomer copolymerizable therewith with a polymerization initiator and a surfactant. When polymerization is carried out in an aqueous medium in the presence of to produce a polyvinyl chloride resin for paste processing, the following general formula [I]
The present invention relates to a method for producing a polyvinyl chloride resin for paste processing, which comprises performing seed microsuspension polymerization using a surfactant represented by the formula (1).

[0010]

Embedded image [Wherein, R ₁ is an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms, R ₂ is hydrogen or an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms, R ₃ is hydrogen or A propenyl group, A has 2 to 2 carbon atoms
An alkylene group of 4, n is an integer of 1 to 200, and M is an alkali metal, ammonium ion or alkanolamine residue. Hereinafter, the present invention will be described in detail.

Specific examples of the surfactant represented by the above general formula [I] used in the present invention include ammonium salt of a nonylpropenylphenol ethylene oxide 10 mol adduct adduct and sulfate of a nonylpropenylphenol ethylene oxide 20 mol adduct adduct. Ammonium salt, octyldipropenylphenol ethylene oxide 10 mol adduct sulfate ammonium salt, octyldipropenylphenol ethylene oxide 100 mol adduct sulfate ammonium salt, dodecylpropenylphenol ethylene oxide 20 mol, propylene oxide 10 mol random adduct sulfate sodium salt, Dodecylpropenylphenol butylene oxide 4
Mol, ethylene oxide 30 mol block adduct sulfate ester sodium salt and the like.

In the present invention, the above-mentioned surfactants may be used alone or in combination with other surfactants. Specific examples of common surfactants used in combination include:
Alkyl sulfates such as sodium lauryl sulfate, myristyl sulfate, alkylaryl sulfonates such as sodium dodecylbenzenesulfonate and potassium dodecylbenzenesulfonate, sulfosuccinates such as sodium dioctylsulfosuccinate, sodium dihexylsulfosuccinate,
Fatty acid salts such as ammonium laurate and potassium stearate; anionic surfactants such as polyoxyethylene alkyl sulfate salts; polyoxyethylene alkyl aryl sulfate salts; sorbitan esters such as sorbitan monooleate and polyoxyethylene sorbitan monostearate And nonionic surfactants such as polyoxyethylene alkyl phenyl ethers and polyoxyethylene alkyl esters can be used.

In the present invention, the amount of the surfactant used is
The amount is 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the monomer. Preferably it is 5 to 50% by weight of the activator.

The method of adding the surfactant may be a method of batch charging before the start of polymerization, a method of batch charging at a polymerization conversion rate of 85%, and the like. It is preferable to add it because the fine particles can be efficiently suppressed.

In the present invention, the monomers copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate, vinyl propionate, vinyl myristate, vinyl oleate and vinyl benzoate, acrylic acid, methacrylic acid, and the like. Unsaturated carboxylic acids or anhydrides such as maleic acid, fumaric acid, and cinnamic acid, esters of acrylic acid such as methyl, ethyl, butyl, octyl and benzyl, and esters of methacrylic acid such as methyl, ethyl, butyl, octyl and benzyl Unsaturated carboxylic acid esters such as maleic acid ester, fumaric acid ester and cinnamic acid ester; vinyl ethers such as vinyl methyl ether, vinyl amyl ether and vinyl phenyl ether; monoolefins such as ethylene, propylene, butene and pentene; Vinylidene,
It is one or more types of ordinary vinyl compounds that can be radically copolymerized with vinyl chloride, such as styrene and its derivatives, acrylonitrile, and methacrylonitrile.

The production method used in the present invention comprises the steps of: about 0.5 μm seed particles containing an oil-soluble polymerization initiator, and 0.1 to 0.2 μm seed particles containing no initiator, if necessary; In the presence of a monomer and a surfactant, at a temperature of 30 to 80
This is a seed microsuspension polymerization method in which polymerization is carried out at ℃.

In the present specification, the seed particles containing no initiator are added to obtain a paste salt visol having a desired viscosity by changing the particle size distribution of the vinyl chloride polymer latex. It is characterized in that the number of particles of the vinyl chloride polymer latex, particularly particles having a particle size of 0.45 μm or less, increases as the amount of the seed particles increases.

[0018]

The present invention will be described below in more detail with reference to examples.

The production of the seed particles used in each of the following examples was carried out as follows.

Preparation of seed particles containing oil-soluble polymerization initiator 360 kg of deionized water, 300 kg of vinyl chloride monomer and 5.7 kg of lauroyl peroxide were placed in a 1 m ³ autoclave.
And 30 kg of a 15% by weight aqueous solution of sodium dodecylbenzenesulfonate were charged, and the polymerization solution was circulated using a homogenizer for 3 hours.
And proceeded with polymerization. After the pressure has dropped, the unreacted vinyl chloride monomer is recovered and the solids content 35% by weight of the particles have an average particle size of 0.55 μm and 2% by weight of the polymer based lauroyl peroxide. (Hereinafter abbreviated as Seed 1) was obtained.

Preparation of seed particles containing no polymerization initiator In a 1 m ³ autoclave, 400 l of deionized water, 350 kg of vinyl chloride monomer, 2 kg of 16 wt% aqueous solution of potassium laurate, 5 kg of 16 wt% aqueous solution of sodium dodecylbenzenesulfonate And the temperature was increased to 54 ° C. to proceed with the polymerization. After the pressure was reduced, unreacted vinyl chloride monomer was recovered to obtain a latex (hereinafter abbreviated as seed 2) having a solid content of 40% by weight and particles having an average particle size of 0.15 μm. .

Example 1 In a 2.5 l autoclave, 500 g of deionized water, 800 g of vinyl chloride monomer, and a 5% by weight nonylpropenylphenol ethylene oxide 10 mol adduct sulfate ammonium salt aqueous solution (Daiichi Kogyo Co., Ltd.) Pharmaceutical Co., Ltd .: Aqualon HS-1
0) 16 g, 90 g of seed 1 and 110 g of seed 2 were charged, and the temperature of the reaction mixture was raised to 64 ° C. to initiate polymerization. From the start of polymerization to the polymerization conversion rate of 85%,
To 100 parts by weight of the vinyl chloride monomer, 0.7 part by weight of a 5% by weight nonylpropenylphenol ethylene oxide 10 mol adduct sulfate aqueous solution of ammonium salt (hereinafter abbreviated as HS-10) was continuously added. The polymerization pressure is 6 kg /
When the cm ² dropped, the polymerization was stopped, and the unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex. Table 1 shows the physical properties of the latex.

Incidentally, the physical properties of the latex were measured by the following methods.

(1) Solid content 1 g of latex was dried in an oven at 115 ± 2 ° C. for 1 hour, taken out, cooled in a desiccator for 30 minutes, and the solid content was calculated by the following formula: solid content (%) = ｛after drying Weight (g) / latex weight (g)｝ × 100.

(2) Average particle size Laser diffraction type particle size distribution analyzer (LA-
700).

(3) Composition of Small Particles Particles having a particle size of 0.45 μm or less were measured using a laser diffraction particle size distribution analyzer (manufactured by Hiac / Leico, Nicom Model 370).

Example 2 5% by weight of H as a surfactant
The same procedure as in Example 1 was carried out except that a mixture of an aqueous solution of S-10 and a 5% by weight aqueous solution of sodium dodecylbenzenesulfonate was used so that the ratio of the aqueous solution of HS-10 was 25% by weight of the total aqueous solution of surfactants. Thus, a vinyl chloride polymer latex was obtained.

Comparative Example 1 A vinyl chloride polymer latex was obtained in the same manner as in Example 1, except that a 5% by weight aqueous solution of sodium dodecylbenzenesulfonate was used as a surfactant.

Comparative Example 2 A vinyl chloride polymer was prepared in the same manner as in Example 1 except that the amount of seed 2 was 65 g and a 5% by weight aqueous solution of sodium trioxyethylene dodecylphenol ether sulfonate was used as a surfactant. Latex was obtained.

Table 1 shows the physical properties of the latex of Example 2 and Comparative Examples 1 and 2.

[0031]

[Table 1] Example 3 Deionized water 5 in a 2.5 l autoclave
00 g, 800 g of vinyl chloride monomer, and a 5 wt% aqueous solution of HS-10 and a 5 wt% aqueous solution of sodium lauryl sulfate as surfactants so that the ratio of the HS-10 aqueous solution is 12.5 wt% of the surfactant. 16 g of the mixture,
95 g of seed 1 and 4 g of a 0.1 wt% aqueous solution of copper sulfate were charged, and the temperature of the reaction mixture was raised to 48 ° C.
150 g of a 5% by weight aqueous solution of ascorbic acid was continuously added throughout the entire polymerization time. Further, from the initiation of the polymerization to the polymerization conversion of 85%, 0.7 parts by weight of the above mixed surfactant aqueous solution was continuously added to 100 parts by weight of the vinyl chloride monomer. When the polymerization pressure dropped ² kg / cm ² from the saturated vapor pressure of vinyl chloride at 48 ° C., the polymerization was stopped, and the unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex.

Example 4 400 kg of deionized water, 400 kg of vinyl chloride monomer, a 10% by weight aqueous solution of HS-10 and a 25% by weight aqueous solution of sodium lauryl sulfate were used as a surfactant in a 1 m ³ autoclave. 2 kg of a mixture obtained by mixing so that the ratio becomes 12.5% by weight of the surfactant, 50 kg of seed 1 and 0.1% by weight
A 1 kg aqueous solution of copper sulfate was charged and the temperature of the reaction mixture was set to 48 ° C.
And 0.1% by weight ascorbic acid aqueous solution 3
0 kg was added continuously throughout the entire polymerization time. Furthermore,
Between the start of the polymerization and the polymerization conversion of 85%, 0.7 parts by weight of the above mixed surfactant aqueous solution was continuously added to 100 parts by weight of the vinyl chloride monomer. Polymerization pressure of 48
The polymerization was stopped when the pressure dropped by ² kg / cm ² from the saturated vapor pressure of vinyl chloride at ° C, and the unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex.

Comparative Example 3 Example 3 was repeated except that a 5% by weight aqueous solution of sodium lauryl sulfate was used as a surfactant.
In the same manner as in the above, a vinyl chloride polymer latex was obtained.

Comparative Example 4 25% by weight of surfactant
A vinyl chloride polymer latex was obtained in the same manner as in Example 5, except that an aqueous solution of sodium lauryl sulfate was used.

The physical properties of the vinyl chloride polymer latexes of Examples 3 to 6 and Comparative Examples 3 and 4 are shown in Table 2.

[0036]

[Table 2] The composition of the fine particles in Table 2 is indicated by a laser diffraction particle size distribution analyzer (manufactured by Hiac / Leuco: Nicomp Model 3).
In 70), measurement of fine particles of 0.15 μm or less was performed.

From Tables 1 and 2, it can be seen that by using HS-10 alone or in combination with other surfactants for polymerization,
It can be seen that small particles and fine particles can be reduced.

Reference Example 1 The vinyl chloride polymer latex obtained in Example 1 was spray-dried to obtain paste PVC.
A paste salt visol was prepared using the following composition, and the sol physical properties were measured. Table 3 shows the physical properties of the sol.

The methods of blending and measuring the paste salt visol used in each test shown in Table 3 are as follows.

Formulation 1 (for measuring viscosity and viscosity change over time) Paste PVC 100 parts Dioctyl phthalate 60 parts Formulation 2 (for measuring gelation start temperature) Paste PVC 100 parts Dioctyl phthalate 60 parts Ca / Zn stabilizer 2 parts .

(1) Viscosity measurement The paste PVC of Formulation 1 was measured with a B8H type viscometer. Measurement conditions Rotor: No. 4 spindle rotation speed: 20 rpm Measurement temperature: 25 ° C.

(2) Change with time in viscosity The viscosity is defined by a value represented by the following equation. Change in viscosity over time = sol viscosity at 40 ° C. after 24 hours after sol adjustment / sol viscosity at 40 ° C. after 2 hours after sol adjustment.

(3) Gelation onset temperature The paste salt visol of Formulation 2 was mixed with a torque rheometer (Ha).
Rheocord Sy made by ake Buckler
The kneading torque vs. kneading obtained by kneading under the following conditions according to step 40). It refers to the resin temperature determined by extrapolating the rising portion of the resin temperature curve to the torque as a straight line. Measurement conditions Mixer: Rheomix 600 type rotor: Sigma rotor Mixer set temperature: 190 ° C. Rotor rotation speed: 60 rpm.

Reference Example 2 The sol physical properties were measured in the same manner as in Reference Example 1, except that the vinyl chloride polymer latex obtained in Comparative Example 1 was used.

Reference Example 3 The sol physical properties were measured in the same manner as in Reference Example 1, except that the vinyl chloride polymer latex obtained in Example 3 was used.

Reference Example 4 The sol physical properties were measured in the same manner as in Reference Example 1, except that the vinyl chloride polymer latex obtained in Example 4 was used.

Reference Example 5 The sol physical properties were measured in the same manner as in Reference Example 1, except that the vinyl chloride polymer latex obtained in Comparative Example 3 was used.

Reference Example 6 The sol properties were measured in the same manner as in Reference Example 1, except that the vinyl chloride polymer latex obtained in Comparative Example 4 was used.

Table 3 shows the sol properties of Reference Examples 2 to 6.

[0050]

[Table 3] Table 3 shows that the paste PVC sol prepared from the paste PVC obtained from the latex polymerized using HS-10 has a low viscosity, a small change in viscosity with time, and a low starting temperature under gel.

[0051]

According to the present invention, in the production of polyvinyl chloride resin for paste processing by seed microsuspension polymerization, the generation of fine particles during polymerization is suppressed, the viscosity is low, the viscosity does not change with time, and the gelation is achieved. A polyvinyl chloride resin for paste processing, which gives a paste vissol having excellent meltability, is obtained.

Claims (3)

(57) [Claims] 1. A method of polymerizing a vinyl chloride monomer alone or a vinyl chloride monomer and a vinyl monomer copolymerizable therewith in an aqueous medium in the presence of a polymerization initiator and a surfactant. A method for producing a polyvinyl chloride resin for paste processing, comprising using a surfactant represented by the following general formula [I] to perform seed microsuspension polymerization when producing a polyvinyl chloride resin for paste processing. Embedded image [Wherein, R ₁ is an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms, R ₂ is hydrogen or an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms, R ₃ is hydrogen or A propenyl group, A has 2 to 2 carbon atoms
An alkylene group of 4, n is an integer of 1 to 200, and M is an alkali metal, ammonium ion or alkanolamine residue. ] 2. The method according to claim 1, wherein the surfactant represented by the general formula [I] is added during a polymerization conversion of 85% or less. 3. The amount of a surfactant used in the polymerization is 0.01 to 5 parts by weight based on 100 parts by weight of a vinyl chloride monomer or a vinyl monomer copolymerizable with the vinyl chloride monomer. The method of claim 1.