JPH09176211A - Production of vinyl chloride polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vinyl chloride polymer having a high degree of polymerization and a high gel fraction at good efficiency by subjecting a vinyl chloride monomer (A) to emulsion polymerization or fine suspension polymerization in such a manner that an emulsion of a polyfunctional monomer (B) copolymerizable with component A is added to the system. SOLUTION: Component A is a vinyl chloride monomer itself or a mixture thereof with a monomer (e.g. vinylidene chloride) copolymerizable therewith. The content of the comonomer should be 20wt.% or below, based on component A. Component B has two or more ethylenically unsaturated bonds copolymerizable with component A and is exemplified by diallyl phthalate. The amount of component B used should be 0.01-1.0wt.% based on component A. To prepare the dispersion of component B, an anionic emulsifier (e.g. sodium laurylsulfate) is used. The amount of the emulsifier used is 10-500wt.% based on the weight of component B, and the amount of the water used in this preparation is about 3-50 times as high as that of component B.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the production of vinyl chloride-based polymers by emulsion polymerization or fine suspension polymerization, and more specifically, vinyl chloride-based polymers having a high average degree of polymerization and tetrahydrofuran (hereinafter , "THF" may be abbreviated as "THF").

[0002]

2. Description of the Related Art Emulsion polymerization or fine suspension of vinyl chloride monomer or a mixture of vinyl chloride monomer and a monomer copolymerizable therewith (hereinafter referred to as "vinyl chloride monomer"). When a vinyl chloride polymer is polymerized to increase the average degree of polymerization of the vinyl chloride polymer or to generate a THF insoluble component (hereinafter, referred to as “gel component”), conventionally, A polyfunctional monomer having two or more ethylenic double bonds copolymerizable with a vinyl chloride-based monomer, an emulsifier and a vinyl chloride-based monomer in an aqueous medium (hereinafter, referred to as “polyfunctional monomer”). ]) Are collectively added before the polymerization or divided or continuously added during the polymerization. However, in this method, probably because the dispersion of the polyfunctional monomer in the polymerization system is not good, the supply of the polyfunctional monomer into the micelle is insufficient, and therefore the average degree of polymerization cannot be sufficiently increased. However, there was a problem that a sufficient gel content was not generated.

Further, in suspension polymerization, a method for improving fish eye and processability by adding a polyfunctional monomer as a dispersion in which polyvinyl alcohol is dispersed is disclosed in JP-A-3-47808. However, in emulsion polymerization or fine suspension polymerization, since the stirring is weaker than in suspension polymerization, the dispersed state of the polyfunctional monomer is not good just by dispersing with polyvinyl alcohol, and the above-mentioned problems Could not be resolved.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a vinyl chloride polymer having a high average degree of polymerization when a vinyl chloride polymer is produced by emulsion polymerization or fine suspension polymerization of a vinyl chloride monomer. Another object of the present invention is to provide a method for producing a vinyl chloride polymer having a high gel content in the polymer.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, by using the polyfunctional monomer after emulsifying it, it is possible to obtain a chloride having a high average degree of polymerization. The present invention was completed by finding that a vinyl polymer and a vinyl chloride polymer having a high gel content can be efficiently obtained. That is, the gist of the present invention is that a vinyl chloride monomer or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith (a vinyl chloride monomer) can be copolymerized with a vinyl chloride monomer. When an emulsion polymerization or a fine suspension polymerization is performed in the presence of a polyfunctional monomer having two or more ethylenic double bonds (polyfunctional monomer), the polyfunctional monomer is anionic in advance. In a method for producing a vinyl chloride-based polymer, which is characterized by adding to a polymerization system as an emulsion dispersed in water using a system emulsifier. As a monomer, diallyl phthalate, diallyl isophthalate,
The above method for producing a vinyl chloride polymer using at least one selected from diallyl terephthalate and triallyl isocyanurate, and the addition amount of the polyfunctional monomer is 0.01 to 1 with respect to the vinyl chloride monomer. It exists in the above-mentioned method for producing a vinyl chloride-based polymer, which is 0.0% by weight.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The vinyl chloride monomer used in the present invention is usually a vinyl chloride monomer alone, or a mixture of a vinyl chloride monomer and another monomer copolymerizable therewith. Other monomers copolymerizable with the vinyl chloride monomer include halogenated unsaturated monomers such as vinylidene chloride, vinyl acetates such as vinyl acetate, vinyl propionate and vinyl stearate, methyl vinyl ether, ethyl vinyl ether, etc. Vinyl ethers, mono-unsaturated acids such as acrylic acid, methacrylic acid, itaconic acid or alkyl esters such as methyl ester and ethyl ester of these mono-unsaturated acids,
Examples thereof include diunsaturated acids such as maleic acid and fumaric acid, acid anhydrides of maleic acid, alkyl esters such as methyl esters and ethyl esters thereof, unsaturated nitriles such as acrylonitrile. You may use these monomers in mixture of 2 or more types.

These monomers are 2% of vinyl chloride type monomers.
It is preferably used in an amount of 0% by weight or less, particularly 10% by weight or less. In the present invention, when the vinyl chloride-based monomer is polymerized, the polymerization is performed in the presence of a polyfunctional monomer which is previously dispersed (emulsified) in water using an anionic emulsifier. The emulsion of the polyfunctional monomer can be added all at once in the polymerization tank before the start of the polymerization, or divided or continuously before the polymerization to during the polymerization,
It is particularly preferable to add it when the polymerization conversion rate is 0 to 70%.

The polyfunctional monomers used in the present invention include diallyl esters of aromatic divalent carboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, triallyl esters such as trimellitic acid and cyanuric acid. , Diallyl or divinyl esters of aliphatic divalent carboxylic acids such as succinic acid, adipic acid, maleic acid, fumaric acid and itaconic acid, vinyl (meth) acrylate, (meth) acrylic acid such as allyl (meth) acrylate Vinyl and allyl esters of acid, diallyl ether, ethylene glycol,
Vinyl ethers of polyhydric alcohols such as n-butanediol, ethylene glycol, propylene glycol,
Examples thereof include di- or tri (meth) acrylic acid esters of polyhydric alcohols such as 1,4 butanediol, glycerin, trimethylolethane, trimethylolpropane and tetramethylolmethane.

Among them, diallyl phthalate, diallyl isophthalate, diallyl terephthalate and triallyl isocyanurate are suitable for use in the present invention because they are easily available and have good reactivity. These polyfunctional monomers may be used alone or in combination of two or more. The amount of the polyfunctional monomer used is preferably 0.01 to 1.0% by weight based on the vinyl chloride monomer. If the amount of the polyfunctional monomer is less than 0.01% by weight, the crosslinking does not proceed sufficiently and the vinyl chloride polymer having a high average degree of polymerization may not be obtained.

On the other hand, if the amount is more than 1.0% by weight, it becomes difficult for the vinyl chloride polymer particles to absorb the plasticizer during molding. Examples of anionic emulsifiers used when preparing emulsions of polyfunctional monomers include alkali metal salts and ammonium salts of higher alcohol sulfates such as sodium lauryl sulfate, and alkylbenzene sulfonic acids such as sodium dodecylbenzenesulfonate. Alkali metal salts and ammonium salts, polyoxyethylene alkyl ether sulfonic acid alkali metal salts and ammonium salts, higher fatty acid alkali metal salts and ammonium salts, sulfosuccinic acid dialkyl ester alkali metal salts, and other anionic surfactants. Can be mentioned. These emulsifiers may be used alone or in combination of two or more kinds. The amount of these emulsifiers used is about 10 to 500% by weight based on the weight of the polyfunctional monomer. Further, the amount of water used when preparing the emulsion of the polyfunctional monomer is
The amount is about 3 to 50 times the weight of the polyfunctional monomer.
The emulsion is obtained by mixing a polyfunctional monomer, an anionic emulsifier and water with an emulsifying mixer such as a high speed homogenizer.

The emulsifier used in the polymerization is not particularly limited, and examples thereof include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, sorbitan fatty acid ester, and polyoxyethylene alkyl ether in addition to the above-mentioned anionic surfactant. Examples thereof include nonionic surfactants such as oxyethylene higher fatty acid ester, and these may be used alone or in combination of two or more kinds. The amount of these emulsifiers used is 0.1 with respect to the vinyl chloride monomer.
Is about 3 to 3% by weight, preferably about 0.3 to 1% by weight.

As the polymerization initiator, in the case of emulsion polymerization,
For example, persulfates such as sodium persulfate, potassium persulfate, ammonium persulfate, and water-soluble peroxides such as hydrogen peroxide, or these peroxides with sodium sulfite, sodium pyrosulfite, ammonium sulfite, sodium hydrogen sulfite, and ascorbine. A redox initiator comprising an acid and a water-soluble reducing agent such as sodium formaldehyde sulfoxylate is used, and in the case of fine suspension polymerization, for example, azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, lauroyl. Peroxide, t-
A monomer-soluble (oil-soluble) initiator such as butyl peroxypivalate or a redox initiator composed of these oil-soluble initiators and the above water-soluble reducing agent is used. The amount of these polymerization initiators used is about 0.005 to 0.05% by weight based on the vinyl chloride monomer.

Further, during the polymerization, auxiliary agents such as a chain transfer agent may be used for the purpose of adjusting the molecular weight distribution of the vinyl chloride polymer. Examples of the chain transfer agent include trichloroethylene, carbon tetrachloride, 2-mercaptoethanol, octyl mercaptan and the like. These emulsifiers, polymerization initiators, etc. used in the polymerization reaction may be added to the polymerization reaction system all at once, or may be added in portions or continuously during the polymerization reaction. In the present invention, a vinyl chloride-based polymer separately prepared in advance during polymerization is charged as a seed polymer in a polymerization tank, and then the vinyl chloride-based monomer and the emulsifier described above are added to carry out the polymerization. Good.

In the present invention, the polymerization temperature is not particularly limited, but is usually 40 to 70 ° C., and the reaction pressure at that time is 5 to 1
It is about ² kg / cm ² G. The polymerization time is generally about 5 to 10 hours. In the present invention, the vinyl chloride monomer is emulsified and dispersed in the aqueous medium to carry out the polymerization reaction. The amount of the aqueous medium used in this case is 0.8 to the weight of the vinyl chloride monomer. It is about 1.3 times the amount.

After removing unreacted monomers from the dispersion liquid (hereinafter referred to as "latex") of the vinyl chloride polymer obtained by the above method, a method using a rotary disk, a two-fluid nozzle or the like is used. Spray-dry to obtain a vinyl chloride polymer. Further, the obtained vinyl chloride polymer may contain various compounding agents such as a plasticizer, an organic solvent, a stabilizer, a filler, an antioxidant, an ultraviolet absorber, an antistatic agent, a colorant, and a release agent. It is blended and used as a plastisol or an organosol.

[0016]

EXAMPLES Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to the description of the following examples unless it exceeds the gist. The evaluations in Examples and Comparative Examples were performed by the following methods. <Evaluation method> Measurement of THF insoluble content (gel content) About 1 g of a vinyl chloride polymer was placed in 80 ml of THF, stirred for 1 hour, and then sonicated for 5 minutes. After centrifugal sedimentation with a centrifugal separator at 10000 G (gravitational acceleration) for 35 minutes, the supernatant was removed, 25 ml of THF was added again, and ultrasonic waves were irradiated for 5 minutes. Centrifuge again at 10000 G for 30 minutes in a centrifuge,
The supernatant was removed, and the residue was dried in a vacuum dryer at 40 ° C and -700m.
After drying under conditions of mHg and 12 hours, the residue is precisely weighed.
The gel content is calculated by the following formula.

[0017]

[Equation 1]

Average degree of polymerization According to JIS K6721, the viscosity is measured with an Ubbelohde viscometer to calculate the average degree of polymerization.

Example 1 Volume 200 L equipped with a stirrer
90 kg of deionized water at a temperature of 54 ° C., 12 g of ammonium persulfate and 75 g of ammonium sulfite were placed in the polymerization tank of 1) and stirred for about 20 minutes to dissolve. Next, the inside of the polymerization tank was depressurized to -610 mmHg and kept at 54 ° C for 50 minutes. 60 kg of vinyl chloride monomer was charged into the polymerization tank, and the temperature inside the tank was adjusted to 50 ° C. After 15 minutes from the charging of the monomer, a 0.2% aqueous solution of ammonium persulfate was gradually added at a rate of about 10 ml / min, and then the reaction was performed while controlling the polymerization rate to a constant value, and then the polymerization rate was increased. 8% of sodium lauryl sulphate when it reaches about 15%
Start adding the aqueous solution and add 80 ml /
It was added at a rate of about 10 minutes until the total amount of sodium lauryl sulfate added reached 300 g. The tank pressure is 50 ° C
From the saturation pressure of vinyl chloride monomer at 2.0 kg / cm
^{When 2} G was dropped, the reaction was stopped and unreacted monomers were recovered to obtain a polymer latex. The obtained latex was a monodisperse particle having a particle size of about 0.52 μm ^{* 1} . Then
In a polymerization tank having a volume of 200 L equipped with a stirrer, 4.5 kg (as vinyl chloride resin) of the latex obtained in the previous period, 80 kg of deionized water and 90 g of ammonium sulfite were charged, and then the inside of the polymerization tank was-
Reduced pressure to 610 mmHg, vinyl chloride monomer 75.5
kg was charged and the temperature was adjusted to 47 ° C. Then, 10 L of a 0.1% aqueous solution of ammonium persulfate was initially added at a rate of 10 ml / min for about 15 minutes, and then continuously added while controlling the addition rate so as to maintain a constant polymerization rate. Then, the previously prepared emulsion of diallyl phthalate ^{* 2} was added all at once. Polymerization rate is 10
% Of ammonium myristate was continuously added at a rate of about 0.7 L / hour from the time when the amount reached 100% to the end of the polymerization so that 0.5 kg of ammonium myristate was added. Polymerization was stopped when the pressure in the tank dropped 1.0 kg / cm ² G from the saturation pressure of the vinyl chloride monomer at 47 ° C., and unreacted monomer was recovered to obtain a latex. Further, the latex was heated and stirred under reduced pressure at 80 ° C. for 3 hours to collect and remove residual monomers. Rotating disk type spray dryer with inlet temperature 165 ° C and outlet temperature 5
It was dried at 5 ° C. and pulverized to obtain a vinyl chloride polymer.

The above evaluations were carried out using this vinyl chloride polymer, and the results are summarized in Table 1. * 1: Laser diffraction particle size analyzer LA- manufactured by Horiba Ltd.
Measured at 910 * 2: 40 g of diallyl phthalate (0.05% by weight relative to vinyl chloride monomer) was added to 1 L of a 4% aqueous solution of sodium lauryl sulfate, and a high-speed homogenizer (manufactured by Terraoka: Hiscotron NS-50 ( Generator shaft NS-20MG)) for 10 minutes, 10000r
emulsion of diallyl phthalate obtained by mixing at pm

Example 2 The amount of diallyl phthalate used in Example 1 was 80 g.
A vinyl chloride-based polymer was obtained in the same manner as above, except that (0.1% by weight based on the vinyl chloride-based monomer), and was evaluated. The results are summarized in Table 1. Example 3 In Example 1, the amount of diallyl phthalate used was 240
A vinyl chloride polymer was obtained and evaluated in the same manner except that the amount was changed to g (0.3% by weight based on the vinyl chloride monomer). The results are summarized in Table 1.

Example 4 The amount of diallyl phthalate used in Example 1 was 80 g.
Then, a vinyl chloride polymer was obtained in the same manner except that the emulsion of diallyl phthalate was continuously added at a rate of 0.25 L / hour from the time when the polymerization rate reached 10% for 4 hours, and evaluated. did. The results are summarized in Table 1.

Example 5 A vinyl chloride polymer was obtained and evaluated in the same manner as in Example 3 except that diallyl terephthalate was used instead of diallyl phthalate. The results are summarized in Table 1. Example 6 A vinyl chloride polymer was obtained in the same manner as in Example 1 except that triallyl isocyanurate was used instead of diallyl phthalate, and this was evaluated. The results are summarized in Table 1.

Comparative Example 1 A vinyl chloride polymer was obtained and evaluated in the same manner as in Example 1 except that diallyl phthalate was not added as an emulsion but added as it was. The results are summarized in Table 1. Comparative Example 2 A vinyl chloride polymer was obtained and evaluated in the same manner as in Example 2 except that diallyl phthalate was added as it was without forming an emulsion. The results are summarized in Table 1.

Comparative Example 3 A vinyl chloride polymer was obtained and evaluated in the same manner as in Example 3 except that diallyl phthalate was added as it was without forming an emulsion. The results are summarized in Table 1. Comparative Example 4 A vinyl chloride polymer was obtained in the same manner as in Example 5, except that diallyl terephthalate was added as it was without forming an emulsion, and this was evaluated. The results are summarized in Table 1.

Comparative Example 5 A vinyl chloride polymer was obtained and evaluated in the same manner as in Example 6 except that triallyl isocyanurate was not added as an emulsion but added as it was. Table 1 shows the results.
Summarized in Comparative Example 6 A vinyl chloride polymer was obtained in the same manner as in Example 1 except that diallyl phthalate was not added, and this was evaluated. The results are summarized in Table 1.

Comparative Example 7 A vinyl chloride polymer was obtained in the same manner as in Example 1 except that partially saponified polyvinyl alcohol (PVA) having a saponification degree of 80 mol% was used instead of sodium lauryl sulfate. evaluated. The results are summarized in Table 1. Comparative Example 8 A vinyl chloride polymer was obtained and evaluated in the same manner as in Example 2, except that partially saponified polyvinyl alcohol (PVA) having a saponification degree of 80 mol% was used instead of sodium lauryl sulfate. The results are summarized in Table 1.

[0028]

[Table 1]

According to the present invention, when the same amount of the polyfunctional monomer is used, it is compared with the case where the polyfunctional monomer is added as it is without being made into an emulsion or when it is dispersed by a dispersant and added. A vinyl chloride polymer having a high average degree of polymerization or a vinyl chloride polymer having a high gel content can be obtained (the addition efficiency of the polyfunctional monomer is high).

[0030]

According to the present invention, a vinyl chloride polymer having a high average degree of polymerization or a vinyl chloride polymer having a high gel content in the polymer can be efficiently obtained.

Claims (3)

[Claims] 1. A vinyl chloride monomer comprising a vinyl chloride monomer or a mixture of a vinyl chloride monomer and a monomer copolymerizable therewith (hereinafter referred to as "vinyl chloride monomer"). During emulsion polymerization or fine suspension polymerization in the presence of a polyfunctional monomer having two or more ethylenic double bonds copolymerizable with (hereinafter, referred to as “polyfunctional monomer”), A method for producing a vinyl chloride polymer, comprising adding the polyfunctional monomer to a polymerization system as an emulsion in which an anionic emulsifier is previously dispersed in water. 2. The method for producing a vinyl chloride polymer according to claim 1, wherein at least one selected from diallyl phthalate, diallyl isophthalate, diallyl terephthalate and triallyl isocyanurate is used as the polyfunctional monomer. 3. The addition amount of the polyfunctional monomer is 0.01 to 1.0% by weight with respect to the vinyl chloride-based monomer.
Alternatively, the method for producing a vinyl chloride polymer according to the item 2 above.