JP2001064312A - Organic peroxide emulsion formulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an organic peroxide emulsion formulation having easy handleability and improved safety and long-term storage stability by mixing an organic peroxide with a dihydric alcohol having a specified flash point, a nonionic surfactant, and water. SOLUTION: This formulation has a freezing point of -15 deg.C or lower and a mean particle diameter of 5 μm or smaller and is obtained by dissolving or dispersing 5-60 wt.% normally liquid organic peroxide, 20-50 wt.% dihydric alcohol having a flash point of at least 95 deg.C and a specific gravity of at most 1.10, and 0.02-6 wt.% nonionic surfactant having an HLB of at least 10 in water. The formulation may additionally contain 0.5-6 wt.% partially saponified polyvinyl acetate having a degree of saponification of 50-90 mol% and an average degree of polymerization of 50-1,000. The formulation is useful as a polymerization initiator for the suspension (co)polymerization or emulsion (co) polymerization of an ethylenically unsaturated monomer. The monomer that is applicable is exemplified by a vinyl halide, a vinylidene halide monomer, a vinyl ether, or a vinyl ester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to an organic peroxide emulsion formulation. More specifically, the present invention relates to an emulsion formulation in which safety is enhanced by adding a specific dihydric alcohol as an antifreezing agent. This organic peroxide emulsion formulation is:
It is useful as a suitable radical polymerization initiator for ethylenically unsaturated monomers.

[0002]

BACKGROUND OF THE INVENTION Aqueous emulsion formulations of liquid organic peroxides can be readily prepared by using surfactants as emulsifiers. To improve the storage stability of these emulsion formulations, frozen emulsions have been proposed (US Pat. No. 3,988,261).

However, most of the liquid organic peroxides usually used as polymerization initiators for vinyl chloride monomers require low-temperature storage, and the storage temperature is 0 ° C. to −25 ° C. Therefore, even if the above-mentioned emulsion formulation has good stability, it freezes at 0 ° C. or lower and loses fluidity, which makes handling difficult.

[0004] However, this was also solved by adding a lower alcohol as an antifreezing agent. In particular, methyl alcohol is convenient because it is economical because it is inexpensive and gives an antifreezing effect when added at a low concentration (JP-A-56-13).
9,509, JP-A-57-28,106).

[0005]

These emulsion formulations of liquid organic peroxides are easier to handle and more excellent in safety than conventionally used solvent-diluted organic peroxides. It has been used as a favorite.

However, these practical problems are that the safety (nonflammability) is insufficient and the long-term storage stability is lacking (Japanese Patent Application Laid-Open No. Sho 62-505).

[0007]

SUMMARY OF THE INVENTION The present inventors have found an emulsion formulation of an organic peroxide which has solved the above-mentioned disadvantages of the prior art, that is, an emulsion formulation having good safety and long-term storage stability. As a result of diligent research with the aim of obtaining a finding that the problem can be solved by blending a specific dihydric alcohol having a high flash point as an antifreezing agent and having a specific gravity of 1.10 or less. Thus, the present invention has been completed.

That is, the present invention relates to the following 1 to 8. 1. An emulsion formulation of an organic peroxide, comprising an organic peroxide, a dihydric alcohol having a flash point of 95 ° C. or higher and a specific gravity of 1.10 or lower, a nonionic surfactant, and water. 2. 2. The emulsion formulation according to claim 1, wherein the organic peroxide is a room temperature liquid and the freezing point of the emulsion formulation is lower than -15 [deg.] C. 3. 3. The emulsion formulation according to the above item 1 or 2, comprising a partially saponified polyvinyl acetate. 4. The emulsion formulation according to any one of the above items 1 to 3, wherein the dihydric alcohol is propylene glycol. 5. The HLB value of the nonionic surfactant is a liquid at room temperature, and the HLB value of the nonionic surfactant is 10 or more in the case of one kind, and 10 or more in the case of two or more kinds. An emulsion formulation according to any one of the preceding clauses. 6. 6. The emulsion blend according to any one of items 3 to 5, wherein the partially saponified polyvinyl acetate has a saponification degree of 50 to 85 mol% and an average degree of polymerization of 1,000 or less. object. 7. 7. The emulsion formulation according to any one of the above items 1 to 6, wherein the organic peroxide is t-butylperoxy 2-ethylhexanoate. 8. A radical polymerization initiator for an ethylenically unsaturated monomer, comprising the emulsion compound according to any one of the above items 1 to 7.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The dihydric alcohol having a flash point of 95 ° C. or higher and a specific gravity of 1.10 or lower used in the present invention is preferably a dihydric alcohol having about 3 to 6 carbon atoms. Preferably, the alcohol is water-soluble.
Further, the specific gravity is preferably in the range of 0.9 to 1.1. This corresponds to, for example, propylene glycol (1,2-propanediol), trimethylene glycol (1,3-propanediol), tetramethylene glycol (1,4-butanediol), pentamethylene glycol (1,5 -Pentanediol), hexylene glycol (2-methyl-2,4-pentanediol)
And so on. More preferable dihydric alcohol is dihydric alcohol having 3 carbon atoms, and propylene glycol is preferable. In the present invention, these dihydric alcohols act as antifreezing agents.

The dihydric alcohol is preferably added so that the freezing point of the emulsion composition is at least -15 ° C. or less, and usually accounts for 20% by weight or more, preferably 30% by weight of the aqueous phase in the emulsion composition. It is preferable to add so that the content is not less than 50% by weight, preferably not more than 45% by weight. On this occasion,
Mixing two or more dihydric alcohols may be used. By blending a dihydric alcohol having a specific low specific gravity value as described above, a specific gravity difference from an organic peroxide having a specific gravity of usually 1.00 or less can be corrected, and it can significantly contribute to improvement of long-term storage stability.

The organic peroxide which can be used in the present invention is preferably one or more organic peroxides which are liquid at room temperature. When these examples are specifically shown, for example, t-butylperoxy 3,5,5-trimethylhexanoate, t-butylperoxy
Butyl peroxyisobutyrate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy pivalate, t-butyl peroxy neoheptanoate, t-butyl peroxy neodecanoate, α- Cumyl peroxy neodecanoate, t-amyl peroxy 3,5,5-trimethylhexisanoate, t-amyl peroxy-2-ethylhexanoate, t-amyl peroxy pivalate, t-hexyl peroxy Pivalate, t-octyl peroxy-2-ethylhexanoate, t-octyl peroxy neodecanoate, 1, 1
Peroxyesters such as -dimethyl-3-hydroxybutylperoxyneodecanoate, diacyl peroxides such as di (3,5,5-trimethylhexanoyl) peroxide and diisobutyryl peroxide;
-Ethylhexyl) peroxydicarbonate, di (3
Peroxydicarbonate such as (-methoxybutyl) peroxydicarbonate; and peroxyketal such as 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane.

In the present invention, in order to improve the thermal stability of the organic peroxide, an organic peroxide diluted with an inert organic solvent in advance can be used. For example, a high-boiling aliphatic hydrocarbon, a plasticizer such as DOP, or a chlorinated paraffin may be used or added.

The content of the organic peroxide in the organic peroxide emulsion composition of the present invention is usually at least 5% by weight, preferably 20% by weight, based on the whole emulsion composition.
%, More preferably 30% by weight or more and 65% by weight or less, usually about 60% by weight or less. If the amount is too small, the transportation cost increases, which is not preferable. Practically, about 50% is advantageous.

The nonionic surfactant used in the present invention acts as an emulsifier, and is preferably a liquid at normal temperature.
When more than one species are used in combination, those having an HLB value of 10 or more for the mixture are preferred. H when used alone
Those having an LB value of 10 or more can be used as they are. Also 2
When two or more kinds are used in combination, usually, one having an HLB value of 9 or less and one having an HLB value in a range of 10 to 20 may be selected, and both may be used as a mixture or the like. Although there is no particular upper limit for the HLB value, it is usually about 20. The addition amount is usually 0.02% by weight or more, preferably 0.05% by weight or more, and about 6% by weight or less, preferably about 4% by weight or less based on the whole emulsion composition.

Preferred nonionic surfactants used in the present invention include sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene fatty acid esters. Specifically, there are the Leo Doll SP (trade name) series, the Leo Doll TW (trade name) series, and the Emanon (trade name) series manufactured by Kao Corporation.

The partially saponified polyvinyl acetate used in the present invention acts as a protective colloid agent.
Usually, the degree of saponification is at least 50 mol%, preferably at least 60 mol%, at most 90 mol%, preferably at most 85 mol%, and the average degree of polymerization is at least 50, preferably at least 100, more preferably at least 150, It is 1000 or less, preferably 800 or less. The amount of the additive cannot be unconditionally determined depending on the kind of the partially saponified polyvinyl acetate used, but is usually 0.5% by weight or more based on the whole emulsion composition.
It is preferably at least 1% by weight and at most 6% by weight, preferably at most 5% by weight. Specifically, Unitika Resin UMR (trade name) series manufactured by Unitika Kasei Co., Ltd.
KL series of Nippon Synthetic Chemical Co., Ltd. and the like.

The organic peroxide emulsion composition of the present invention can be produced by a known method. Specifically, all methods for producing ordinary emulsion formulations can be used, but usually, an aqueous phase in which a nonionic surfactant, a dihydric alcohol, and optionally a partially saponified polyvinyl acetate are dissolved or dispersed in water. Is prepared, and an organic peroxide is charged as an oil phase therein, and emulsification is carried out with a homogenizer.

Equipment that can be used to produce the organic peroxide emulsion formulations of the present invention include, for example, paddle molds,
Propeller type and turbine type mechanical rotary stirrers, colloid mills, homogenizers, high-speed shearing devices, line mixers, ultrasonic homogenizers, etc., are conventionally known. Using these devices, an emulsion formulation of an organic peroxide having an average particle size of 5 μm or less and having good stability can be produced.

The organic peroxide emulsion formulation of the present invention is a polymerization initiator for ethylenically unsaturated monomers. That is, it is useful as a polymerization initiator for a suspension (co) polymerization or emulsion (co) polymerization reaction of an ethylenically unsaturated monomer. Suitable monomers include vinyl halides such as vinyl chloride,
Vinylidene halide type monomer such as vinylidene chloride, vinyl ether, vinyl ester, acrylic acid or methacrylic acid and its ester, a-olefin, aromatic vinyl such as styrene, maleic acid or fumaric acid ester, ethylene, vinyl acetate Can be illustrated. Moreover,
In connection with the production of a superabsorbent polymer, it is also suitable as a polymerization initiator for aqueous (co) polymerization of acrylic acid or acrylate.

[0020]

EXAMPLES The present invention will be described below with reference to examples and comparative examples, but these are for illustration only and do not limit the present invention. All percentages in each example are by weight unless otherwise specified.

Examples 1-3 and Comparative Examples 1-2 Aqueous emulsion formulations shown in Table 1 were prepared by the following method. As an ordinary stirring device, a predetermined amount of pure water is placed in a 1-L glass tall beaker equipped with a homogenizer and a thermometer, and a partially saponified polyvinyl acetate as a protective colloid is charged and dissolved therein with stirring. Next, after a nonionic surfactant and a dihydric alcohol as an antifreezing agent were added and dissolved, the internal temperature was cooled to 10 ° C. or lower. An organic peroxide is charged therein and stirred at a high speed for a predetermined time (50
(00 revolutions, 15 minutes) to obtain an aqueous emulsion formulation of an organic peroxide.

The compounds used in the examples and comparative examples are as follows. Antifreeze propylene glycol: 1,2-propanediol (flash point: 99 ° C, specific gravity: 1.04), hexylene glycol: 2-methyl-2,4-pentanediol (flash point: 102 ° C, specific gravity: 0.92), glycerin: flash point: 177 ° C., specific gravity: 1.
26, Methyl alcohol: Flash point: 12 ° C, specific gravity: 0.7
9

Protective Colloid UMR-20M: Unitika Resin UMR-20M (trade name) (partially saponified polyvinyl acetate), manufactured by Unitika Kasei Co., Ltd., saponification degree: 65 mol%, polymerization degree: 200, KL-05 : Partially saponified polyvinyl acetate, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., having a saponification degree of 80 mol% and a polymerization degree of 500

Emulsifier (nonionic surfactant) Emanone 4110 (trade name) (HLB: 11.6),
REODOL SP-O10 (trade name) (HLB: 4.
3), Rheodol TW-O120 (trade name) (HLB:
15.0) are all manufactured by Kao Corporation.

Organic peroxide Kayaester O (trade name): t-butylperoxy 2-
Ethyl hexanoate (pure), Trigonox 36 (trade name): di (3,5,5-trimethylhexanoyl) peroxide (pure), Kayacarbone EH (trade name): di (2-ethylhexyl) peroxy Dicarbonate (pure) All products are manufactured by Kayaku Akzo.

Further, a safety test (flash point test), a viscosity measurement, a 0 ° C. accelerated stability test, and a -15 ° C. freezing confirmation test of the obtained aqueous emulsion formulation were carried out as follows. Table 1 shows the results together with the composition.

Safety Test (Flash Point Test) Evaluation was carried out using a Cleveland open-type flash point tester specified in JIS-K2274-62. Those not ignited are indicated by ○, those ignited are indicated by x, and the temperature in parentheses after x indicates the ignition temperature. Viscosity measurement The viscosity at -5 ° C was measured using an E-type viscometer (manufactured by Tokyo Keiki). Immediately after the preparation and one month after storage in a static state (−5 ° C.), the measurement was carried out to confirm whether or not the viscosity had changed over time. 0 ° C Accelerated Stability Test The obtained aqueous emulsion formulation was placed in a glass container and stored at 0 ° C. One month later, the presence or absence of layer separation was observed. If there was no generation of a transparent liquid based on the organic peroxide in the upper layer and there was no transparent aqueous layer in the lower layer, the stability was determined to be good. When either one or both had a transparent separation layer, the stability was poor. −15 ° C. freezing confirmation test The obtained aqueous emulsion formulation was placed in a test tube, and −1
It was stored in a thermostat at 5 ° C. One week later, the contents were visually checked for freezing.

Table 1 shows that the examples are superior to the comparative examples in any of the tests.

[0029]

[Table 1]

[0030]

EFFECTS OF THE INVENTION The organic peroxide emulsion formulation of the present invention to which a specific dihydric alcohol having a high flash point is added does not show a flash point and is nonflammable, so that it is highly safe and can be handled remarkably. It became easier. In addition, by incorporating the dihydric alcohol, the long-term storage stability of the emulsion was remarkably improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C07C 409/38 C07C 409/38

Claims (8)

[Claims] An organic peroxide comprising a dihydric alcohol having a flash point of 95 ° C. or higher and a specific gravity of 1.10 or lower, a nonionic surfactant and water. Emulsion formulation. 2. The emulsion formulation according to claim 1, wherein the organic peroxide is a room temperature liquid and the freezing point of the emulsion formulation is lower than -15.degree. 3. The emulsion formulation according to claim 1, which comprises a partially saponified polyvinyl acetate. 4. The emulsion formulation according to claim 1, wherein the dihydric alcohol is propylene glycol. 5. The nonionic surfactant is a liquid at room temperature, and has an HLB value of 10 or more for one kind or a mixture of two or more kinds. The emulsion formulation according to any one of items 1 to 4. 6. The degree of saponification of a partially saponified polyvinyl acetate product.
The emulsion formulation according to any one of claims 3 to 5, wherein the amount is 50 to 85 mol% and the average degree of polymerization is 1000 or less. 7. An organic peroxide comprising t-butylperoxy 2
The emulsion formulation according to any one of claims 1 to 6, wherein the emulsion formulation is -ethylhexanoate. 8. A radical polymerization initiator for an ethylenically unsaturated monomer, comprising the emulsion blend according to any one of claims 1 to 7.