JPH0656915A - Production of polyvinyl chloride resin for paste processing - Google Patents

Abstract

PURPOSE:To prevent minute particles from being produced and obtain the polyvinyl chloride resin having a low viscosity and hardly undergoing change in viscosity during aging by subjecting vinyl chloride to a seed microsuspension polymn. in an aq. medium in the presence of a specific surfactant. CONSTITUTION:The resin is produced by subjecting vinyl chloride alone or together with another copolymerizable vinyl monomer to a seed microsuspension polymn. in an aq. medium in the presence of a surfactant of the formula (wherein R1 is 6-18C alkyl, alkenyl, or aralkyl; R2 is H, 6-18C alkyl, alkenyl, or aralkyl; R3 is H or propenyl; A is 2-4C alkylene; n is 1-200; and M is an alkali metal, an ammonium ion, or an alkanolamine) (e.g. an ammonium salt of a sulfuric ester of an adduct of 10mol of ethylene oxide to 1mol of nonylpropenylphenol).

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 improved by a seed microsuspension polymerization method. More specifically, in the production of a polyvinyl chloride resin for paste processing by seed microsuspension polymerization, the generation of fine particles during polymerization is suppressed, the viscosity is low and the viscosity does not change over time, and the gelling meltability is excellent. The present invention relates to a method for producing a polyvinyl chloride resin for paste processing, which gives a paste PVC sol.

[0002]

2. Description of the Related Art Generally, a method for producing polyvinyl chloride for paste processing (hereinafter, abbreviated as paste vinyl chloride) is a process for producing an interface between a vinyl chloride monomer and a vinyl monomer copolymerizable therewith in an aqueous medium. Polymerization is performed in the presence of an activator and a polymerization initiator while stirring at a predetermined temperature, and the obtained polymer latex is spray-dried. The dried resin is used as it is, or if necessary, crushed to an appropriate size, or further granulated, etc. before use. The obtained paste vinyl chloride is kneaded with a compounding agent such as a plasticizer, a stabilizer and a diluent, and used as a paste vinyl chloride sol for processing.

The paste polyvinyl chloride sol obtained as described above is processed by a coating method, slush molding, dip molding, rotational molding or the like to obtain a molded product. At that time, if the sol viscosity at the time of processing is high or the speed of gelling and melting is slow, for example, the processing speed at the time of coating cannot be increased and the productivity is affected, or a uniform molded product cannot be obtained, or However, there is a problem that the processing becomes difficult because the viscosity changes with time.

It is considered that these problems in the paste vinyl chloride sol are caused by the basic particle size of the paste vinyl chloride sol.

The seed microsuspension polymerization method is about 0.5 μm
The seed particles containing the oil-soluble polymerization initiator of 1. are used alone or, if necessary, the seed particles containing no oil-soluble polymerization initiator are used, and the seed particles are grown to about 0.1 μm to 2 μm.
It is a manufacturing method peculiar to paste PVC that obtains particles of about m. When seed microsuspension polymerization is carried out using commonly used anionic and nonionic surfactants,
A large number of fine particles of less than 0.1 μm other than the charged seed particles are generated mainly at the final stage of polymerization.

[0006] A large number of these particles having a size of less than 0.1 µm are generated when the polymer latex is dried to obtain paste PVC.
When this is used as a paste vinyl chloride sol in order to enhance the cohesive force between particles of 0.1 μm to 2 μm, the viscosity increases due to the deterioration of dispersibility in a liquid component such as a plasticizer and the porosity formed by the agglomerates. It is considered that this is the cause of the change over time in the sol becoming large due to absorption of liquid components into the sexual portion.

Various methods have been tried for the purpose of obtaining a sol in which the viscosity is reduced and the viscosity is little changed with time. As an example, a method of using an alkali metal salt or ammonium salt of polyoxyethylene alkylphenol ether sulfate in microsuspension polymerization (Japanese Patent Publication No. 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 Laid-Open No. 61-44907) and the like. In particular, no solution has been made by suppressing fine particles generated during polymerization.

[0008]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The inventors of the present invention have earnestly studied a method for producing a paste vinyl chloride having a low viscosity, a small change in viscosity with time, and an excellent gelling meltability. The present invention has been reached by the finding that paste PVC that sufficiently satisfies the above requirements can be obtained by performing seed microsuspension polymerization using the surfactant shown.

[0009]

[Means for Solving the Problems] That is, the present invention uses a vinyl chloride monomer alone or a vinyl chloride monomer and a vinyl monomer copolymerizable therewith as a polymerization initiator and a surfactant. When a polyvinyl chloride resin for paste processing is polymerized in an aqueous medium in the presence of 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

[0010]

[Chemical 2] [In the formula, 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 Propenyl group, A has 2 to 2 carbon atoms
4 is an alkylene group, n is an integer of 1 to 200, and M is an alkali metal, ammonium ion or alkanolamine residue. The present invention will be described in detail below.

Specific examples of the surfactant represented by the above general formula [I] used in the present invention include nonylpropenylphenol ethylene oxide 10 mol adduct sulfate ammonium salt, nonylpropenylphenol ethylene oxide 20 mol adduct sulfate ester. Ammonium salt, octyl dipropenylphenol 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 sulfuric acid ester sodium salt and the like.

In the present invention, the above surfactant may be used alone or in combination with another surfactant. Specific examples of general surfactants used in combination include
Sodium lauryl sulfate, alkyl sulfate salts such as myristyl sulfate, sodium dodecylbenzenesulfonate, alkylarylsulfonates such as potassium dodecylbenzenesulfonate, sodium dioctylsulfosuccinate, sulfosuccinate salts such as sodium dihexylsulfosuccinate,
Anionic surfactants such as fatty acid salts such as ammonium laurate and potassium stearate, polyoxyethylene alkyl sulfate ester salts, polyoxyethylene alkylaryl sulfate ester salts, sorbitan esters such as sorbitan monooleate and polyoxyethylene sorbitan monostearate Conventionally known compounds such as nonionic surfactants such as compounds, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters and the like can be used.

In the present invention, the amount of the surfactant used is
The amount of the surfactant 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, and the surfactant represented by the general formula [I] is used in terms of polymerization stability. It is preferably 5 to 50% by weight of the amount of the activator.

The surfactant may be added all at once before the start of the polymerization, or at a polymerization conversion rate of 85% at once, but it may be continuously added between the initial stage and the polymerization conversion rate of 85% or less. Addition is preferable from the viewpoint that fine particles can be efficiently suppressed.

The monomers copolymerizable with vinyl chloride in the present invention include vinyl esters such as vinyl acetate, vinyl propionate, vinyl myristate, vinyl oleate, vinyl benzoate, acrylic acid, methacrylic acid, Unsaturated carboxylic acids such as maleic acid, fumaric acid and cinnamic acid or anhydrides thereof, esters of acrylic acid methyl, ethyl, butyl, octyl, benzyl, etc., esters of methacrylic acid methyl, ethyl, butyl, octyl, benzyl, etc. 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, etc. Monoolefins such as ethylene, propylene, butene, pentene, chloride Vinylidene,
It is one or more 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 seed particles of about 0.5 μm containing an oil-soluble polymerization initiator and, if necessary, an initiator-free seed particle of 0.1 to 0.2 μm, vinyl chloride. Temperature of 30 to 80 in the presence of monomer and surfactant
It is a seed microsuspension polymerization method in which the polymerization is carried out at ℃.

In the present specification, the seed particles containing no initiator are those added in order to obtain a paste viscosol 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, especially the particles having a particle size of 0.45 μm or less, increases as the charged amount of the seed particles increases.

[0018]

Embodiments will be described in more detail below with reference to embodiments.

The seed particles used in each of the following examples were manufactured as follows.

Production of seed particles containing oil-soluble polymerization initiator 360 kg of deionized water, 300 kg of vinyl chloride monomer, 5.7 kg of lauroyl peroxide in 1 m ³ autoclave
And 30 kg of a 15 wt% sodium dodecylbenzenesulfonate aqueous solution were charged, and this polymerization solution was circulated for 3 hours using a homogenizer, and after homogenization treatment, the temperature was changed to 45 ° C.
To proceed with the polymerization. After the pressure has dropped, the unreacted vinyl chloride monomer is recovered, particles with a solids content of 35% by weight have an average particle size of 0.55 μm and 2% by weight of polymer based lauroyl peroxide. Was obtained (hereinafter abbreviated as Seed 1).

Preparation of seed particles containing no polymerization initiator 400 l of deionized water, 350 kg of vinyl chloride monomer, 2 kg of 16% by weight potassium laurate aqueous solution, 5% by weight 16% by weight sodium dodecylbenzenesulfonate aqueous solution in 1 m ³ autoclave Was charged and the temperature was raised to 54 ° C. to proceed with 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 diameter of 0.15 μm. .

[Example 1] 500 g of deionized water, 800 g of vinyl chloride monomer and 5% by weight of nonylpropenylphenol ethylene oxide 10 mol adduct sulfate ammonium salt aqueous solution as a surfactant (Daiichi Kogyo) Pharmaceutical Co., Ltd .: Aqualon HS-1
0) 16 g, seed 1 90 g, and seed 2 110 g were charged, and the temperature of this reaction mixture was raised to 64 ° C. to initiate polymerization. Between the start of polymerization and the conversion of polymerization up to 85%,
0.7 parts by weight of a 5% by weight nonylpropenylphenolethylene oxide 10 mol adduct sulfate ammonium salt aqueous solution (hereinafter abbreviated as HS-10) was continuously added to 100 parts by weight of the vinyl chloride monomer. Polymerization pressure at 64 ° C from saturated vapor pressure of vinyl chloride to 6 kg /
Polymerization was stopped when the pressure dropped by cm ² , and unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex. The latex physical properties are shown in Table 1.

The latex physical properties were measured by the following methods.

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

(2) Average particle size Laser diffraction type particle size distribution measuring device (manufactured by Horiba Ltd .: LA-
700).

(3) Small particle composition A particle size distribution of 0.45 μm or less was measured by a laser diffraction type particle size distribution analyzer (manufactured by Hiac / Leuco: Nicomp model 370).

[Example 2] 5 wt% H as a surfactant
Same as Example 1 except that an S-10 aqueous solution and a 5 wt% sodium dodecylbenzenesulfonate aqueous solution were mixed so that the ratio of the HS-10 aqueous solution was 25 wt% of the total surfactant aqueous solution. 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 5% by weight aqueous sodium dodecylbenzenesulfonate solution was used as the surfactant.

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

Physical properties of the latexes of Example 2 and Comparative Examples 1 and 2 are shown in Table 1.

[0031]

[Table 1] Example 3 Deionized water 5 in 2.5 l autoclave
00 g, vinyl chloride monomer 800 g, 5 wt% HS-10 aqueous solution as a surfactant and 5 wt% sodium lauryl sulfate aqueous solution so that the ratio of the HS-10 aqueous solution becomes 12.5 wt% of the surfactant. 16g of the mixture,
95 g of seed 1 and 4 g of 0.1% by weight copper sulfate aqueous solution were charged, and the temperature of the reaction mixture was raised to 48 ° C.
150 g of a 5 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time. Further, 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 from the start of the polymerization until the conversion of the polymerization reached 85%. When the polymerization pressure dropped from the saturated vapor pressure of vinyl chloride at 48 ° C. by 2 Kg / cm ² , the polymerization was stopped and 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, and 10 wt% HS-10 aqueous solution and 25 wt% sodium lauryl sulfate aqueous solution as a surfactant were added to an HS-10 aqueous solution in a 1 m ³ autoclave. 2 kg of a mixture in which the ratio of 1% by weight of the surfactant is 12.5% by weight, 50 kg of seed 1 by 0.1% by weight
Charge 1 kg of aqueous copper sulfate solution and raise the temperature of the reaction mixture to 48 ° C.
To 0.1 wt% ascorbic acid aqueous solution 3
0 kg was added continuously throughout the polymerization time. Furthermore,
From the start of the polymerization until the conversion of the polymerization reached 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 is 48
Polymerization was stopped when the vinyl chloride saturation vapor pressure at 2 ° C. dropped by ² Kg / cm ² , and unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex.

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

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

Physical properties of the vinyl chloride polymer latices of Examples 3 to 6 and Comparative Examples 3 to 4 are shown in Table 2.

[0036]

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

From Tables 1 and 2, 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 vinyl chloride.
The paste vinyl chloride sol was prepared using the following formulation and the sol physical properties were measured. The physical properties of the sol are shown in Table 3.

The formulation and measuring method of the paste vinyl chloride sol used in each test shown in Table 3 are as follows.

Formulation 1 (for measuring viscosity and aging of viscosity) Paste PVC 100 parts Dioctylphthalate 60 parts Formulation 2 (for gelation start temperature measurement) Paste PVC 100 parts Dioctylphthalate 60 parts Ca / Zn stabilizer 2 parts .

(1) Viscosity Measurement Paste PVC of the formulation 1 was measured by a B8H type viscometer. Measurement conditions Rotor: No. 4 spindle rotation speed: 20 rpm Measurement temperature: 25 ° C.

(2) Change with time of viscosity Defined by the value represented by the following equation. Change with time of viscosity = 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 vinyl chloride sol of formulation 2 was mixed with a torque rheometer (Ha
ake Buckler Rheocord Sy
kneading torque vs. The resin temperature is obtained by extrapolating the rising portion of the resin temperature curve to the torque by a straight line. Measurement conditions Mixer: Rheomix 600 type Rotor: Sigma rotor Mixer setting temperature: 190 ° C Rotor 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 physical 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.

Physical properties of the sol of Reference Examples 2 to 6 are shown in Table 3.

[0050]

[Table 3] From Table 3, it can be seen that the paste vinyl chloride sol prepared from the paste vinyl chloride obtained from the latex polymerized by using HS-10 has a low viscosity, a small change in viscosity with time, and a low gel starting temperature.

[0051]

EFFECTS OF THE INVENTION According to the present invention, in the production of a polyvinyl chloride resin for paste processing by seed microsuspension polymerization, generation of fine particles during the polymerization is suppressed, and the viscosity is low and the viscosity does not change with time, and gelation occurs. To obtain a polyvinyl chloride resin for paste processing, which gives a paste vinyl sol having excellent meltability.

Claims (3)

[Claims] 1. A vinyl chloride monomer alone or a vinyl chloride monomer and a vinyl monomer copolymerizable therewith are polymerized 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, which comprises subjecting a polyvinyl chloride resin for paste processing to a seed microsuspension polymerization using a surfactant represented by the following general formula [I]. [Chemical 1] [In the formula, 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 Propenyl group, A has 2 to 2 carbon atoms
4 is an alkylene group, 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 the polymerization conversion of 85% or less. 3. The amount of the surfactant used for polymerization is 0.01 to 5 parts by weight based on 100 parts by weight of vinyl chloride monomer or vinyl chloride monomer and vinyl monomer copolymerizable therewith. The method of claim 1.