JPH0286837A - Aqueous emulsified organic peroxide - Google Patents

Abstract

PURPOSE:To obtain a polymn. initiator useful for an ethylenic unsatd. monomer by incorporating a nonionic surfactant mixture, org. peroxide, a solidifying point depressing agent and protective colloid. CONSTITUTION:Aq. emulsified org. peroxide is produced by a known method with 0.1-10wt.% nonionic surfactant mixture having 60-230 hydroxyl group value and consisting of <=30wt.% 10-22C fatty acid ester of sorbitol, <=40wt.% 10-22C fatty acid ester of sorbitan and <=50wt.% 10-22C fatty acid ester of sorbite, 5-80wt.% org. peroxide, 2-30wt.% lower alcohol as a solidifying point depressing agent and 0.1-10wt.% protective colloid to obtain a polymn. initiator useful for an ethylenic unsatd. monomer and having superior stability.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to aqueous emulsified organic peroxides. More specifically, the present invention relates to an aqueous emulsified organic peroxide having good stability. This aqueous emulsified organic peroxide is useful as a polymerization initiator suitable for the polymerization and copolymerization of ethylenically unsaturated monomers, particularly vinyl halide monomers.

(Prior art) Suspension or emulsion polymerization of ethylenically 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 the polymerization reaction. This is done by using an initiator.

Recently, in order to improve productivity when polymerizing ethylenically unsaturated monomers and to prevent environmental pollution due to the toxicity of residual and discarded tlL polymers, the size of Fi synthesis equipment or automatic continuous production equipment has been increased. At the same time, the entire polymerization reaction system is closed.

As a polymerization initiator suitable for such purposes, organic peroxides emulsified with water are easier to handle than the conventionally used solvent-diluted organic peroxides, and are safer. They tend to be preferred because they are excellent.

In recent years, various aqueous emulsified organic peroxides have been proposed in response to the above-mentioned ammonium water.

For example, JP-A-57-167733 discloses organic peroxides, lower alcohols, and specific nonionic surfactants, namely, nonionic surfactants with an HLB value of 10 to 13, and nonionic surfactants with an HLB value of 2 to 5. Aqueous emulsified organic peroxides are disclosed that include aqueous emulsions in combination with nonionic surfactants.

Furthermore, JP-A No. 57-28106 discloses organic peroxides, protective colloid agents, lower alcohols, and nonionic surfactants that do not contain polyethylene oxide groups, such as aqueous surfactants containing sorbitan monolaurate and sorbitan monopalmitate. Emulsified organic peroxides are disclosed. However, the hydroxyl value of nonionic surfactants is 1. For example, sorbitan monolaurate has a value of 250 to 450, and sorbitan monopalmitate has a value of 200 to 400.1 Usually, a wide range of types are included in one name. has been done.

<Problem to be solved by the invention> These known aqueous emulsified organic peroxides include:
There are the following drawbacks 0 For example, Japanese Patent Application Laid-Open No. 57-18773
The aqueous emulsified organic peroxide described in Publication No. 3 has poor storage stability and readily separates into two layers. Moreover, the electrical properties of the polymer obtained using this are poor, that is, the volume resistivity of the polymer is small.

Also, whether the storage stability of the aqueous emulsified organic peroxide described in JP-A No. 57-28106 and the electrical properties of the polymer have been improved, or whether the manufacturing conditions are slightly different, or even if the raw materials or the same lot are used. Small changes in the emulsification conditions can significantly deteriorate the properties of the prepared product, often leading to problems of phase separation. Furthermore, if it is left under vibrating conditions for a long time, the viscosity will drop significantly and then it will separate into two layers. These phenomena become more pronounced as the proportion of oil in the emulsion increases, and becomes a serious problem when the proportion of oil in the emulsion increases.

<Means for Solving the Problem> As a result of intensive research to obtain an aqueous emulsified organic peroxide free from the above-mentioned drawbacks, the present inventors have developed a specific nonionic surfactant having a hydroxyl value within a specific range. We have completed the present invention by confirming that by containing a mixture of the following, it is possible to obtain an aqueous emulsicated organic peroxide that has good storage stability even if the manufacturing conditions are slightly changed and does not separate even when vibrated for a long time. Ta.

That is, the present invention consists of fatty acid esters of sorbitol, sorbitan, and sorbite each having a carbon number of 10 to 22, and the content of sorbitol fatty acid ester, sorbitan fatty acid ester, and sorbite fatty acid ester is 30% or less and 40% or more, respectively, in terms of mass percentage. 2. A nonionic surfactant mixture, an organic peroxide, which is 50% or less and has a hydroxyl value of 60 to 230! The present invention relates to an aqueous emulsified organic peroxide containing a layer-depressing agent or a protective colloid agent as a substantial main component.

Next, each component of the aqueous emulsified organic peroxide of the present invention will be explained.

(a) Nonionic Surfactants This nonionic surfactant is a mixture of primarily mono-, di-, and tri-fatty acid esters made from sorbitol derivatives such as sorbitol, sorbitan, and sorbite. Here, the fatty acid is -C,l n-3+ CnH
tn-s, n = 9-21). Specifically, the fatty acids include linear and branched saturated fatty acids such as lauric acid, myristic acid, valmitic acid, stearic acid and isostearic acid, monoene unsaturated fatty acids such as oleic acid and elaidic acid, such as linoleic acid, polyene unsaturated fatty acids such as eleostearic acid, lylunic acid, oxygenated fatty acids such as ricinoleic acid, and corn oil fatty acids, olive oil fatty acids,
There are fatty acids from natural sources such as rice bran oil fatty acids, safflower oil fatty acids, and tall oil fatty acids.

In addition, the ratio of sorbitol fatty acid ester, sorbitan fatty acid ester, and sorbite fatty acid ester is 30% or less, 40% or more, and 50% or less, preferably 1 to 50% by weight.
30%, 42-LIo%, 3-50%, and the hydroxyl value of the mixture of nonionic surfactants is 60-230.
Anything outside this range will result in poor stability. Here, the hydroxyl value is the B number of potassium hydroxide required to neutralize acetic acid bound to the acetylated product obtained from 1 g of sample oil.

The proportion of the nonionic surfactant in the aqueous emulsion-formed organic peroxide is 0.1 to 10% by weight, preferably 0.5 to 5% by weight. If it is less than 0.1%, the stability will not be sufficient, and 10, f! If the amount exceeds i%, not only will the viscosity become too high, but it will also be economically disadvantageous.

The above-mentioned nonionic surfactant may be a general nonionic surfactant, such as propylene glycol fatty acid ester, alcoholic acid, or It may also contain a nonionic surfactant containing a sugar fatty acid ester or a polyethylene oxide group.

(b) Organic peroxide The organic peroxide used in the present invention is usually one or more organic peroxides whose temperature exhibits a half-life of 10 hours or below 75°C and whose freezing point is below O'C. It is a thing. In this case, the present invention also includes a mixed organic peroxide in which the freezing point of the mixture of the organic peroxide and an organic peroxide having a freezing point of O'C or lower is 0°C or lower.

Specific examples of the organic peroxides include di(n-propyl)peroxydicarbonate, di(isopropyl)peroxydicarbonate, di(5ec-butyl)peroxydicarbonate, capriloxydicarbonate, di(2 -peroxydicarbonates such as -ethylhexyl)peroxydicarbonate, di(2-ethoxyethyl)peroxydicarbonate, di(methoxyisopropyl)peroxydicarbonate, t-butylperoxy-2-ethylhexanoate, t-butylperoxybicarbonate, etc. Peroxy esters such as ester, t-butyl peroxyneodecanoate, cumyl peroxyneodecanoate.

There are diacyl peroxides such as dipropionyl peroxide, diisobutyryl peroxide, and di(3,5,5-trimethylhexanoyl) peroxide.

Furthermore, in the present invention, in order to improve the thermal stability of the organic peroxide or to lower the freezing point, organic peroxides diluted with organic solvents may also be used. For example, benzene, toluene, aliphatic hydrocarbons, dimethyl phthalate, etc. There are 11 plasticizers such as dioctyl phthalate. When used, the content of organic solvent is 4% in the aqueous emulsion of organic peroxide.
It is within 0% by weight.

In the organic peroxide aqueous emulsion of the present invention, the content of the organic peroxide is usually 5 to 80! fL is 1%, and if it is too small, transportation costs will increase, which is economically unfavorable. Practically preferred is 10 to 5% by weight of G.

(C) Freezing point depressant The freezing point depressant used in the present invention may be any of those previously used for the purpose of freezing point depressants in aqueous emulsions of organic peroxides. Lower alcohols are particularly preferred. For example, methyl alcohol, ethyl alcohol, ethylene glycol, diethylene glycol,
The content of triedylene glycol and glycerin is usually 2% to 30% by weight.

(d) Protective colloid agent The protective colloid agent used in the present invention is 1. For example, water-soluble cellulose derivatives such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose, and hydroxyethyl cellulose, partially or completely saponified polyvinyl acetate,
It is polyvinylpyrrolidone. The type and amount of the protective colloid agent are appropriately selected depending on the type of organic peroxide and the desired viscosity of the aqueous emulsion of the organic peroxide to be obtained.
Its content is substantially in the range 0.1-10% by weight.

Moreover, it may be one type or a mixture of two or more types.

The protective colloid agent is used for the purpose of increasing the storage stability of the aqueous emulsified organic peroxide. However, if a low viscosity is preferred for easy transfer, no protective colloid is added.

The aqueous emulsified organic peroxide of the present invention is produced by a known method. Specifically, all conventional methods for producing aqueous emulsions can be used, but usually the partially saponified polyvinyl acetate and freezing point depressant are dissolved or dispersed in the aqueous phase, while the organic peroxide is mixed with the organic peroxide as an oil phase. Dissolve or disperse the active agent. Mix the oil phase with the water phase by stirring. Furthermore, it is made into an emulsion using a homogeneous dispersion machine. The product thus obtained exhibits excellent properties in terms of stability and safety because it uses water as a continuous phase.

In addition to the above-mentioned components, the aqueous emulsion of an organic peroxide of the present invention may contain an inorganic salt such as sodium chloride to an extent that does not affect storage stability.

The aqueous emulsified organic peroxide of the present invention can be produced using conventional methods such as paddle-type, propeller-type, or turbine-type mechanical stirrers, colloid mills, homogenizers, high-speed shearing devices, line mixers, and ultrasonic homogenizers. The equipment listed can be used. By using these devices to form an emulsion with an average particle size of 10 gm or less, it is possible to make it extremely stable.

The aqueous emulsified organic peroxides of the present invention are useful as suspension polymerization or copolymerization initiators for ethylenically unsaturated monomers. Applicable monomers include vinyl halides such as vinyl chloride, vinyl halide monomers such as vinylidene halide, vinyl ethers, esters of acrylic acid or methacrylic acid, aromatic vinyls such as styrene, maleic acid or fumaric acid. Examples include acid esters, ethylene, and vinyl acetate. And particularly preferred is vinyl chloride.

When carrying out suspension fR polymerization, for example, water, dispersion aid and the above monomer are charged in a mixing vessel, then an aqueous emulsion organic peroxide is charged, and polymerization is performed by stirring and heating to obtain one quality product. A high quality polymer is obtained. Methods for charging the aqueous emulsified organic peroxide include diluting it with water to an appropriate viscosity and charging it by pumping. At that time, the amount of the aqueous emulsified organic peroxide used is within the usual usage range.

<Effects of the Invention> The aqueous emulsified organic peroxide of the present invention has various advantages. First, even if the manufacturing conditions and emulsification conditions of the raw materials vary somewhat, the stability of the prepared product is always excellent. One of the reasons for this is that the particle size distribution in the emulsion is narrower than before. Secondly, if it is left under conditions where slight vibrations are applied for a long period of time, the viscosity will not drop significantly and then separate into two layers, so it can be handled and transported extremely easily during use. Third, even if separated, it can easily return to its original uniform state when redispersed. These effects are greater than conventional ones, especially when the oil content in the aqueous emulsion is as high as 50% by weight or more. When used as a polymerization initiator, it is easier to handle and can be carried out safely than conventional polymerization initiators.

(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.

Examples 1 to 8 and Comparative Examples 1 to 2 Aqueous emulsified organic peroxides having the formulations shown in Table 1 were manufactured as follows.

First, the 500 was equipped with a propeller blade type stirring device and a thermometer.
Water, freezing point depressant, and protective colloid were added to the third flask of sJ2. After dissolving, approximately 1O
An aqueous solution at °C was obtained. On the other hand, when a solution obtained by mixing a nonionic surfactant and an organic peroxide was added dropwise into an aqueous solution while stirring, the stirring was continued for 30 minutes, resulting in a milky white aqueous emulsion. We were able to obtain organic peroxide.

The symbols in the table have the following meanings.

STO: sorbitol fatty acid ester, ST8: sorbitan fatty acid ester, SR: sorbite fatty acid ester.

Furthermore, the types of fatty acids in the table indicate the names of the fatty acids that are the main components. For example, the nonionic surfactant number a is made from a fatty acid containing 70% by weight of oleic acid.

Using this as a sample, the following stability tests, viscosity measurements,
A vibration test and a polymerization test were conducted.

[Stability test] Place the sample in a glass container maintained at -15°C, sample small amounts from the upper and lower layers of the glass container over time, and measure the content of organic peroxide using the iodometry method. did. The period of stability was defined as the number of days until the difference in the content of organic peroxide between the layer and the lower layer became 10% or more. The results are shown in Table 2.

[Viscosity measurement] Viscosity was measured immediately after manufacture and after vibration testing.

That is, immediately after production, the viscosity of the sample at O''C was measured using a B-type viscometer (Tokyo Keiki Seisakusho Department, rotation speed: zonpM). , sampled at Taiyo Kagaku Kogyo Co., Ltd.: 1O
After vibrating Og for 5 hours, the viscosity was measured. The results are shown in Table 2.

Table 2 shows that the aqueous emulsified organic intoxicant of the present invention has excellent standing stability, and there is little difference in viscosity between immediately after production and after the vibration test, and the comparative example shows that it has excellent standing stability. This shows that it has poor stability and is vulnerable to vibration.

[Polymerization Test] Polymerization tests of vinyl chloride were conducted as follows using the aqueous emulsified organic peroxides of the present invention shown in Examples 1 to 8 as polymerization initiators. That is, 0.45 parts by weight of polyvinyl alcohol, 300 parts by weight of water, 100 parts by weight of vinyl chloride, and the amount of aqueous emulsified organic peroxide shown in Table 3 were placed in an autoclave and heated with stirring until the temperature reached 58°C. The reaction was continued by heating until one polymerization reaction was completed.

The resulting polymer was filtered and dried to obtain white powdery polyvinyl chloride. The yield is shown in Table 3.

] Knee-nose-2L Table 3 shows that polyvinyl chloride can be synthesized safely and in high yield by carrying out a polymerization reaction using the polymerization initiator according to the present invention.

Claims (4)

[Claims] (1) Sorbitol, sorbitan, and sorbite are composed of fatty acid esters with carbon numbers of 10 to 22, and the content of sorbitol fatty acid ester, sorbitan fatty acid ester, and sorbite fatty acid ester is 30% by weight each.
% or less, 40% or more, and 50% or less, and whose hydroxyl value is 60 to 230, the substantial main component is a nonionic surfactant mixture, an organic peroxide, a freezing point depressant, or further a protective colloid agent. Aqueous emulsion containing organic peroxide. (2) The content of the nonionic surfactant mixture is 0.1~
10% by weight, the content of organic peroxide is 5-80% by weight,
Claim 1: The content of the freezing point depressant is 2 to 30% by weight.
aqueous emulsion of organic peroxides. (3) The aqueous emulsified organic peroxide according to claim 1, wherein the content of the protective colloid agent is 0.1 to 10% by weight. (4) A polymerization initiator for suspension polymerization or copolymerization of ethylenically unsaturated monomers comprising the aqueous emulsified organic peroxide according to claim 1.