JPH0588252B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for suspension polymerization of vinyl chloride unsaturated monomers. More specifically, an organic peroxide is used as a polymerization initiator; first, an oil-in-water emulsion-forming organic peroxide containing a specific protective colloid with high water solubility is produced, and then polymerization is performed with this organic peroxide. The vinyl chloride monomer is copolymerized or copolymerized with the vinyl chloride monomer to be treated.

(Prior art) Suspension polymerization of vinyl chloride-based unsaturated monomers usually uses a protective colloid agent and/or a surfactant to obtain a polymer with a desired particle size, and a polymerization process to cause a polymerization reaction. This is done by using an initiator.

Recently, in order to improve productivity when manufacturing vinyl chloride polymers and to prevent environmental pollution due to the toxicity of residual and discarded monomers, polymerization equipment has been increased in size and production equipment has been automated and continuous. At the same time, the entire polymerization reaction system is closed.

As a polymerization initiator for vinyl chloride unsaturated monomers suitable for such purposes, organic peroxide emulsified with water is better than the conventionally used organic peroxide diluted with an organic solvent. tends to be preferred. This is because the latter is a polymerization initiator that is easier to use from the viewpoints of handling, safety, toxicity, etc.

Regarding the recently proposed water-emulsified polymerization initiators, when producing pasty vinyl chloride polymers, radical polymerization initiators, surfactants and/or surfactants that are soluble in water, vinyl chloride monomers and/or homogenizing the protective colloid agent and mixing it with vinyl chloride monomer and optionally water;
A method is disclosed in which a vinyl chloride monomer is then polymerized. The protective colloid agents used here are ordinary cellulose derivatives and partially saponified polyvinyl acetate (Japanese Patent Publication No. 58-454).

In addition, as a polymerization initiator for polymerizing and copolymerizing ethylenically unsaturated monomers, an oil-in-water emulsion organic peroxide containing an organic peroxide, a water-soluble alcohol, a surfactant, and/or a protective colloid agent is used. A method is disclosed. The protective colloid used here is also ordinary partially saponified polyvinyl acetate (with a degree of polymerization of 500 to 2500 and a degree of saponification of approx.
80 mol% or more) (Japanese Unexamined Patent Publication No. 57-28106).

(Problems to be Solved by the Invention) However, these methods have the following drawbacks. In other words, the method described in Japanese Patent Publication No. 58-454 requires an emulsifying machine with a strong shearing action to achieve homogenization, and this method also requires the emulsification machine produced by changing the method and rate of addition of each component. The stability of the product may deteriorate significantly. Such emulsions are unsafe and inconvenient to handle.

Furthermore, in the method described in JP-A-57-28106, since a common protective colloid agent is used, when dissolving it in water, the dissolution rate varies significantly depending on the addition method and addition rate. An emulsion produced in an insufficiently dissolved state has poor storage stability and also has disadvantages such as undissolved matter sticking to the walls.

(Means for Solving the Problems) As a result of intensive research in search of a method to solve the above-mentioned drawbacks, the present inventors found that by using a specific protective colloid agent, that is, having a high solubility in water,
Unlike the method shown in Japanese Patent Publication No. 58-454, it does not require an emulsifying machine with a strong shearing action, and as described in Japanese Patent Publication No. 57-28106, a special method for dissolution in water is not required. The present invention was completed based on the knowledge that a stable oil-in-water emulsion organic peroxide can be obtained easily and without any consideration.

That is, the present invention provides a method for suspension polymerizing a vinyl chloride monomer alone or a vinyl chloride monomer and an ethylenically unsaturated monomer copolymerizable with water, an organic peroxide, and a nonionic interface. An oil-in-water emulsion organic peroxide is obtained by stirring the activator and a specific protective colloid at a temperature of 5 to 30°C, and then vinyl chloride monomer or vinyl chloride monomer and the monomer are mixed. An ethylenically unsaturated monomer copolymerizable with the vinyl chloride monomer is allowed to coexist with the oil-in-water emulsified organic peroxide, and the coexisting material is polymerized or copolymerized with the vinyl chloride monomer under polymerization conditions such as heating. The present invention relates to a suspension polymerization method of vinyl chloride-based unsaturated monomers, which is characterized by polymerization.

As mentioned above, the method of the present invention is applicable not only to suspension polymerization of vinyl chloride monomer alone but also to suspension copolymerization of vinyl chloride monomer and other ethylenically unsaturated monomers. Examples of the ethylenically unsaturated monomer include vinyl ester, vinyl ether, acrylic acid or methacrylic ester, α-olefin, aromatic vinyl, vinyl halide other than vinyl chloride, vinylidene halide, maleic acid or fumaric acid ester, etc. Illustrated. These are generally used in amounts of up to 30% by weight when mixed with vinyl chloride.

In the method of the present invention, during polymerization, specific
That is, the oil-in-water emulsified organic peroxide is characterized by the presence of an oil-in-water emulsified organic peroxide produced using a protective colloid having a high dissolution rate in water, so this oil-in-water emulsified organic peroxide will be explained first.

The organic peroxide used in the method of the present invention may be an organic peroxide that is liquid at room temperature, and in the case of an organic peroxide that is solid at room temperature, it is sufficient that it can form an oil-in-water emulsion, and that they coexist with the organic solvent. You may. Specifically, examples of organic peroxides include di(n
-propyl) peroxydicarbonate, di(isopropyl)peroxydicarbonate, di(Sec-butyl)peroxydicarbonate, di(capryl)peroxydicarbonate, di(2
-ethylhexyl) peroxydicarbonate,
Peroxydicarbonates such as di(methoxyisopropyl)peroxydicarbonate, t-butylperoxyneodecanoate, t-amylperoxyneodecanoate, t-hexylperoxyneodecanoate, cumylperoxyneodecanoate, t- -butyl peroxypivalate,
t-Amylperoxypivalate, t-hexylperoxypivalate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,
Peroxy esters such as 5-trimethylhexanoate and t-butylperoxy-2-ethylhexanoate; diacyls such as diacetyl peroxide, dipropionyl peroxide, diisobutyryl peroxide, and di(3,5,5-trimethylhexanoyl peroxide); peroxide, t-
There are hydroperoxides such as butyl hydroperoxide and cumene hydroperoxide.
In the case of an organic peroxide containing an organic solvent, aromatic hydrocarbons such as toluene and xylene and aliphatic hydrocarbons such as mineral spirits are usually used as the organic solvent. Solid organic peroxides dissolved in organic solvents can be used in the same way as liquid organic peroxides.

The content of the organic peroxide in the oil-in-water emulsion is usually 5 to 80% by weight, but if it is too small, a large amount of emulsion will be required to carry out the present invention, which will increase transportation costs and be uneconomical. If it is too large, it will be difficult to obtain a product with excellent safety, so it is preferably 10 to 65% by weight.

The nonionic surfactants for producing the oil-in-water emulsified organic peroxide used in the method of the present invention include all those used in conventional oil-in-water emulsified organic peroxides. For example, mono-, di-, and tri-sucrose fatty acid esters, mono-, di-, and tri-sorbitan fatty acid esters, glycerin fatty acid esters, propylene glycol fatty acid esters, sorbitol fatty acid esters, diglycerol fatty acid esters, pentaerythritol fatty acid esters, glucose fatty acid esters. , mannitol fatty acid ester, α
- Methyl glycoside fatty acid ester, ascorbic acid fatty acid ester, maltitol fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polyoxypropylene block polymer, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerin There are fatty acid esters, polyethylene glycol fatty acid esters, etc. The type of nonionic surfactant is appropriately selected depending on the organic peroxide. They may also be used singly or in mixtures of two or more. Furthermore, nonionic surfactants that do not have polyethylene oxide groups are particularly preferred because they do not impair the electrical properties of the polymer. The amount of the nonionic surfactant in the oil-in-water emulsion is usually 0.01 to 20% by weight.
It is. If it is too small, the storage stability of the emulsion will be poor, and if it is too large, it will be economically disadvantageous, so it is preferably 0.1 to 10% by weight.

The protective colloid used in the oil-in-water emulsion used in the method of the present invention must have a high dissolution rate in water. Specifically, when the protective colloid agent is dissolved in water at room temperature, 1
It is a soluble protective colloid that dissolves more than 1% in time.

Protective colloid agents include partially or fully saponified polyvinyl acetate with a low degree of polymerization, or surface-treated water-soluble cellulose derivatives.

Specifically, the degree of saponification of polyvinyl acetate is
The content is 60 mol% or more, and the average degree of polymerization is 600 or less. Surface-treated water-soluble cellulose derivatives include methylcellulose and hydroxypropylmethylcellulose, which have been surface-treated with glyoxal to increase their dissolution rate in cold water. The type and amount of the protective colloid agent to be used are appropriately selected depending on the type of organic peroxide, desired viscosity, and the like. Moreover, it may be one type or a mixture of two or more types.
Usually the amount used is 0.01 to 20% by weight of the oil-in-water emulsified organic peroxide. If it is too small, the effect of stabilizing the emulsion will be small, and if it is too large, it will be economically disadvantageous, so it is preferably in the range of 0.1 to 10% by weight.

In addition, water-soluble low-molecular-weight alcohols such as methyl alcohol, ethyl alcohol, n-
propyl alcohol, isopropyl alcohol,
It may also contain ethylene glycol.

Its content is up to 50% in the emulsion,
An emulsion containing this will not freeze even in cold regions where the room temperature is 0° C. or lower, resulting in improved storage stability.

In carrying out the method of the present invention, the amount of oil-in-water emulsified organic peroxide relative to the monomer to be polymerized is the same as in the usual suspension polymerization of vinyl chloride monomer, and generally the monomer is 0.001~1 for
It is used in a range of % by weight.

A well-known apparatus can be used to produce the oil-in-water emulsion organic peroxide used in the suspension polymerization of the present invention. For example, a paddle-type, propeller-type, or turbine-type mechanically rotating stirrer can be used. At that time, the stirring temperature is
The temperature is 5-30°C.

The method of the present invention can be carried out in accordance with the conventional method of polymerizing vinyl chloride in an aqueous medium, except for using the above-mentioned oil-in-water emulsion organic peroxide as a polymerization initiator. As the protective colloid agent (separate from the protective colloid agent for oil-in-water emulsion production) used in the process, conventionally known ones may be used in appropriate amounts without any particular limitations.

(Effects of the Invention) Since the method of the present invention is configured as described above, it has several advantages as shown below.

First, when dissolving a protective colloid in water to produce an oil-in-water emulsion organic peroxide, it is possible to easily and quickly dissolve the protective colloid agent without being restricted by the addition method or addition rate. can.

Second, when producing an oil-in-water emulsion organic peroxide, a stable homogeneous dispersion can be obtained with a conventional stirrer without the need for an emulsification machine with strong shearing action.

Thirdly, the oil-in-water emulsified organic peroxide used in the method of the present invention is emulsified in a physically stable manner, and therefore has excellent safety. There is no severe self-accelerating decomposition or violent combustion upon ignition, which occurs with ordinary radical polymerization initiators, and it can be stored, handled and transported very safely.

Fourth, the oil-in-water emulsion organic peroxide is a low viscosity liquid and is suitable for pump transportation.
Moreover, if it adheres or remains inside the container or piping, it can be easily washed away with water.

(Example) Next, an example and a comparative example will be given and explained, but all are for illustrative purposes and the present invention is not limited to them only.

Example 1 172 g of water and 8 g of partially saponified polyvinyl acetate (average degree of polymerization 400 or less, degree of saponification 70-95 Mol%, product name:
UMR-10H (manufactured by Unitika Kasei Co., Ltd.) was added and stirred for 60 minutes while adjusting the liquid temperature to 5°C, resulting in a uniform transparent liquid. Add 160g of di(2-
ethylhexyl) peroxydicarbonate,
48g methyl alcohol, 6g sorbitan laurate (product name: Nonion LP-20R, NOF Corporation)
) and 6g of sorbitan oleate (product name:
A mixed solution consisting of Nonion OP-80R (manufactured by NOF Corporation) was added dropwise while stirring. Stirring was continued for 30 minutes after the dropwise addition, and a stable oil-in-water emulsion of di(2-ethylhexyl) peroxydicarbonate was obtained.

Next, 0.45 g of partially saponified polyvinyl acetate (average degree of polymerization 1500, degree of saponification 90 mol%), 300 g of water,
100 g of vinyl chloride monomer and 0.1 g of the above oil-in-water emulsion di(2-ethylhexyl) peroxydicarbonate were placed in an autoclave and heated to 58°C with stirring for 8 hours until the polymerization reaction was completed. The reaction continued. When the resulting polymer was dried, a white powder of polyvinyl chloride was obtained with a yield of 87%.

Example 2 Polyvinyl chloride was produced in the same manner as in Example 1, except that t-butyl peroxyoctoate was used instead of di(2-ethylhexyl) peroxydicarbonate and the polymerization temperature was changed from 58°C to 75°C. I got it.

Example 3 Methylcellulose surface-treated with glyoxal (trade name: hi-65SH-4000, manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of partially saponified polyvinyl acetate (average degree of polymerization 400 or less, degree of saponification 70 to 95 mol%). ), raise the liquid temperature from 5℃ to 15℃, and stir for 60℃.
Polyvinyl chloride was obtained in the same manner as in Example 1, except that the concentration was changed from 120 min to 120 mol.

Example 4 Instead of vinyl chloride, 90g of vinyl chloride and
Example 1 except that 10 g of vinylidene chloride was used.
Suspension polymerization was carried out according to . As a result, a vinyl chloride-vinylidene chloride copolymer was obtained with a yield of 85%.

Example 5 Partially saponified polyvinyl acetate (average degree of polymerization 400,
Saponification degree 70-95 mol%, product name: UMR-10H,
Partially saponified polyvinyl acetate (average degree of polymerization 400, degree of saponification 100 mol%,
Polyvinyl chloride was obtained by processing in the same manner as in Example 1, except that the liquid temperature was raised from 5°C to 30°C using product name: UMR-10HH (manufactured by Unitika Kasei Co., Ltd.) and methyl alcohol was not used. .

Comparative Example 1 Instead of partially saponified polyvinyl acetate (average degree of polymerization 400 or less, degree of saponification 70 to 95 mol%), ordinary partially saponified polyvinyl acetate (average degree of polymerization 1500, saponification degree 70 to 95 mol%) was used.
Saponification degree of 90 mol %) was put into a three-necked flask similar to that in Example 1 along with water, and stirred while adjusting the liquid temperature to 5° C. in the same manner as in Example 1. But 60
Even after stirring for a minute, the liquid does not become uniform and transparent.
Since most of the partially saponified polyvinyl acetate was dispersed in an undissolved state, subsequent experiments were discontinued.

Comparative Example 2 Instead of partially saponified polyvinyl acetate (average degree of polymerization 400 or less, degree of saponification 70 to 95 mol%), ordinary methyl cellulose (manufactured by Wako Pure Chemical Industries, Ltd.) was used in three mouths in the same manner as in Example 1. The mixture was poured into a flask together with water, and stirred while adjusting the liquid temperature to 5° C. in the same manner as in Example 1. However, even after stirring for 60 minutes, a homogeneous transparent liquid could not be obtained, so subsequent experiments were discontinued.

It is clear that the method of the present invention is superior to the Examples and Comparative Examples.

Claims (1)

[Claims] 1. A method of suspension polymerizing vinyl chloride monomer alone or an ethylenically unsaturated monomer copolymerizable with vinyl chloride monomer, in which water, an organic peroxide and a polyethylene chloride monomer are copolymerized. Nonionic surfactant without ethylene oxide group and average degree of polymerization as a protective colloid agent
600 or less and a water-soluble cellulose derivative surface-treated with polyvinyl acetate or glyoxal with a saponification degree of 60 mol% or more, is stirred at a temperature of 5 to 30°C to obtain an oil-in-water emulsion organic peroxide, and then chlorinated. A vinyl monomer or a vinyl chloride monomer and an ethylenically unsaturated monomer copolymerizable with the monomer are allowed to coexist with the oil-in-water emulsified organic peroxide, and the coexistence is controlled under polymerization conditions. 1. A method for suspension polymerization of vinyl chloride-based unsaturated monomers, which comprises polymerizing or copolymerizing vinyl chloride monomers by placing the vinyl chloride monomers therein. 2. The method for suspension polymerization of vinyl chloride unsaturated monomers according to claim 1, wherein the protective colloid agent is contained in the oil-in-water emulsion organic peroxide in an amount of 0.01 to 20% by weight.