JPH06107711A - Production of vinyl chloride polymer for paste processing - Google Patents

Abstract

PURPOSE:To obtain a vinyl chloride resin prevented in the generation of fine particles in the polymerization reaction, having a low viscosity, reduced in the change in the viscosity with the lapse of time, and useful for paste processing by subjecting vinyl chloride monomer to a seed microsuspension polymerization using a specific surfactant. CONSTITUTION:The method for producing a polyvinyl chloride resin by subjecting (A) vinyl chloride monomer and arbitrarily a copolymerizable to seed microsuspension polymerization in the presence of (B) approximately 0.5mum diameter seed particles containing an oil-soluble polymerization initiator and, if necessary, 0.1-0.2mum seed particles not containing the polymerization initiator in an aqueous medium at 30-80 deg.C comprises adding a surfactant composition containing 5-50wt.% (based on the total amount of the surfactant composition) of a surfactant of the formula (R1 is 6-18C alkyl, alkenyl, aralkyl; R2 is H, the same as R1;R3 is H or propenyl; A is 2-4C alkylene; (n) is an integer of 1-200: M is alkali metal, ammonium ion, or alkanolamine residue) in an amount of 0.05-5 pts.wt. based on the component A and by controlling the polymerization conversion efficiency to <=85%.

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 paste vinyl chloride resin, which gives polyvinyl chloride (hereinafter abbreviated as paste vinyl chloride) sol for paste processing.

[0002]

2. Description of the Related Art Generally, a method for producing paste vinyl chloride is carried out by stirring a vinyl chloride monomer or a vinyl monomer copolymerizable therewith in an aqueous medium in the presence of a surfactant and a polymerization initiator at a predetermined temperature. It is polymerized while being dried, and the polymer latex obtained is spray-dried. The dried resin is used as it is, or if necessary, crushed to an appropriate size, or further granulated to be used. 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 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 porous portion formed by the agglomerate. It is considered that this is a cause of the aging change of the sol due to absorption of liquid components into the sol.

Various methods have been attempted for the purpose of obtaining a sol having a reduced viscosity and a small viscosity change 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. Sho 63-3516).
6), 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 given 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, according to the present invention, a vinyl chloride monomer alone or a vinyl chloride monomer and a vinyl monomer copolymerizable therewith are used in the presence of a polymerization initiator and a surfactant. Polyvinyl chloride resin for paste processing, characterized in that, when polymerized in an aqueous medium to produce a paste vinyl chloride resin, a surfactant represented by the following general formula [I] is used for seed micro suspension polymerization. The present invention relates to a manufacturing method of.

[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, nonylpropenylphenol ethylene oxide 20 mol adduct,
Octyl dipropenylphenol ethylene oxide 10
Mol adduct, octyl dipropenylphenol ethylene oxide 100 mol adduct, dodecyl propenylphenol ethylene oxide 20 mol, propylene oxide 1
0 mol random adduct, dodecylpropenylphenol butylene oxide 4 mol, ethylene oxide 30 mol block adduct and the like can be mentioned.

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.

Vinyl monomers copolymerizable with vinyl chloride in the present invention include vinyl esters such as vinyl acetate, vinyl propionate, vinyl myristate, vinyl oleate and 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., methyl esters of methacrylic acid, ethyl, butyl, octyl, benzyl etc. Unsaturated carboxylic acid esters such as esters, maleic acid esters, fumaric acid esters, cinnamic acid esters, vinyl ethers such as vinyl methyl ether, vinyl amyl ether, vinyl phenyl ether, ethylene, propylene,
It is one or more of ordinary vinyl compounds that can be radically copolymerized with vinyl chloride, such as monoolefins such as butene and pentene, vinylidene chloride, 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. A latex containing (hereinafter abbreviated as seed 1) was obtained. -Production of seed particles containing no polymerization initiator Into a 1 m ³ autoclave, 400 l of deionized water, 350 kg of vinyl chloride monomer, 2 kg of 16 wt% potassium laurate aqueous solution, and 5 kg of 16 wt% sodium dodecylbenzenesulfonate aqueous solution were charged. The temperature was raised to 54 ° C. to proceed 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 diameter 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 mol% nonylpropenylphenol ethylene oxide 20 mol adduct aqueous solution as a surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): Aqualon RN-2
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. From the start of the polymerization until the conversion of the polymerization reaches 85%, 0.7 parts by weight of 5 parts by weight is added to 100 parts by weight of the vinyl chloride monomer.
Wt% nonylpropenylphenol ethylene oxide 1
A 0 mol aqueous solution of the adduct (hereinafter abbreviated as RN-20) was continuously added. When the polymerization pressure drops 6 kg / cm ² from the saturated vapor pressure of vinyl chloride at 64 ° C, the polymerization is stopped,
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) Solid content content 1 g of latex is dried in an oven at 115 ± 2 ° C. for 1 hour, taken out, cooled in a desiccator for 30 minutes, and solid content is calculated from the following formula.

Solid content (%) = {weight after drying (g) / weight of latex (g)} × 100 (2) Average particle size Laser diffraction type particle size distribution measuring instrument (manufactured by Horiba Ltd .: LA-70)
It was measured at 0). (3) Small particle composition A small particle of 0.45 μm or less was measured with a laser diffraction type particle size distribution measuring device (manufactured by Hiac / Leuco: Nicomp model 370).

Example 2 5 wt% RN-20 aqueous solution and 5 wt% as a surfactant
RN with sodium dodecylbenzene sulfonate solution
A vinyl chloride polymer latex was obtained in the same manner as in Example 1 except that the mixture was used such that the ratio of the -20 aqueous solution was 12.5% by weight of the surfactant.

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

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

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

Example 3 500 g of deionized water, 800 g of vinyl chloride monomer and 5 wt% RN as a surfactant in a 2.5 l autoclave.
-20 aqueous solution and 5 wt% sodium lauryl sulfate aqueous solution were mixed so that the ratio of the RN-20 aqueous solution was 12.5 wt% of the surfactant, and 16 g of seed 1 was used.
5 g and 4 g of a 0.1 wt% copper sulfate aqueous solution were charged and the temperature of the reaction mixture was raised to 48 ° C., and 150 g of a 0.05 wt% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time. Furthermore, the polymerization conversion rate is 85% after the start of polymerization.
Until then, 0.7 parts by weight of the above mixed surfactant aqueous solution was continuously added to 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 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% by weight as a surfactant in a 1 m ³ autoclave.
An RN-20 aqueous solution and a 25 wt% sodium lauryl sulfate aqueous solution are added, and the ratio of the RN-20 aqueous solution is 1% of the surfactant.
2 kg of a mixture of 2.5% by weight, 50 kg of seed 1 and 1 kg of 0.1% by weight copper sulfate aqueous solution were charged and the temperature of the reaction mixture was raised to 48 ° C.
30 kg of a weight% ascorbic acid aqueous solution was continuously added throughout the entire polymerization time. Further, 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 the vinyl chloride monomer.
Polymerization pressure is 48kg from vinyl chloride saturated vapor pressure 2kg
Polymerization was stopped when the pressure dropped by / cm ² and unreacted vinyl chloride monomer was recovered to obtain a vinyl chloride polymer latex.

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

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

The physical properties of the vinyl chloride polymer latices of Examples 3-4 and Comparative Examples 3-4 are shown in Table 2.

The composition of the fine particles in Table 2 was measured with a laser diffraction type particle size distribution measuring device (manufactured by Hiac / Leuco: Nicomp model 370) to measure fine particles of 0.15 μm or less.

From Tables 1 and 2, by using RN-20 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, and 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 Dioctyl phthalate 60 parts Formulation 2 (for gelation start temperature measurement) Paste PVC 100 parts Dioctyl phthalate 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 in viscosity with time It is defined by the value represented by the following formula. Viscosity change with time = sol adjustment, sol viscosity at 40 ° C. after 24 hours / sol viscosity at 40 ° C. after 2 hours after sol adjustment (3) gelation onset temperature Rheometer (Haak
e Buckler Rheocord System 40), and 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 Physical properties of the sol 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 Physical properties of the sol 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 Physical properties of the sol 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 Physical properties of the sol 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 physical properties of Reference Examples 2 to 6. It can be seen from Table 3 that the paste vinyl chloride sol prepared from the paste vinyl chloride obtained from the latex polymerized using RN-20 has a low viscosity, a small change in viscosity with time, and a low gel starting temperature.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

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. A paste vinyl chloride resin that gives a paste vinyl chloride sol having excellent meltability is obtained.

Claims (3)

[Claims] 1. A paste obtained by 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, which comprises performing a seed microsuspension polymerization using a surfactant represented by the following general formula [I] when producing a polyvinyl chloride resin for processing. [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, and R ₃ is hydrogen. Or a 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 the polymerization is 0.01 to 5 parts by weight with respect to the vinyl chloride monomer or the vinyl chloride monomer and the vinyl monomer copolymerizable therewith.
The method described in.