JPH01190666A - Aqueous suspension of dibenzoyl peroxide - Google Patents

Abstract

PURPOSE:To obtain the title aqueous suspension containing definite amount of specific polyhydric alcohol and specific surfactant, having excellent storage stability and redispersibility and usable in polymerization of styrene, etc. CONSTITUTION:An aqueous suspension of dibenzoyl peroxide and derivative thereof containing 10-65wt.%, preferably 15-60wt.% one or more kind of polyhydric alcohols (e.g., glucose, sorbitol or trehalose) selected from a group of 6C monosaccharides, hydrogenreduced product thereof and 12C disaccharides and 0.001-10wt.% of nonionic surfactant (e.g., sorbitan oleate) having <=10 HLB value and nonionic surfactant (e.g., polyoxyethylene stearate) having >=10 HLB value or nonionic surfactant having <=10 HLB value and anionic surfactant (e.g., sodium oleate).

Description

Detailed Description of the Invention (Industrial Application Field) This invention relates to an aqueous suspension of dibenzoyl peroxide, and more specifically, it has excellent storage stability and redispersibility, and has low viscosity, making it easy to store. This invention relates to an aqueous suspension of dibenzoyl peroxide suitable for polymerizing ethylenically unsaturated monomers such as styrene, which is easy to handle and transport.

(Prior Art) Dibenzoyl peroxide easily explodes due to impact or friction, so handling it, such as transportation and storage, is dangerous. Therefore, in order to ensure safety during transportation and storage of dibenzoyl peroxide, it is handled in the form of a composition containing water and a plasticizer.

However, these cannot be transported by pump because they are in a powder or paste state. Therefore, in recent years, efforts have been made to develop aqueous suspensions of dibenzoyl peroxide that are fluid enough to be transported by pump and have excellent storage stability. ing.

For example, in JP-A-51-125:102, water, a protective colloid agent, a solid organic peroxide such as dibenzoyl peroxide, and a nonionic interface with an HLB value of 12.5 or less of at least 0.2 weight units are disclosed. a combination of an active agent and a nonionic surfactant with an HLB value of at least 0.2% by weight 2) t),
4j: (at least 0.2 I[tffiX (7) HL
A nonionic surfactant with a B value of 12.5 or less and a minimum of 0.
An aqueous suspension containing 0.1% by weight in combination with an anionic surfactant is shown.

Publication No. 57-501085 also discloses water, at least 18i of a protective colloid, one or more solid organic peroxides, such as dibenzoyl peroxide, fatty acid esters of polyhydric alcohols, and alkanolamides. Aqueous suspensions containing selected 1M1 surfactants are disclosed.

Furthermore, JP-A No. 62-51666 discloses one or more surfactants selected from the group consisting of dibenzoyl peroxide, anionic surfactants and nonionic surfactants, and one or more surfactants having 2 to 6 carbon atoms. Aqueous suspensions of dibenzoyl peroxide containing a range of polyhydric alcohols are disclosed.

Further, JP-A-61-62502 discloses an aqueous suspension containing a soothing peroxide, one or more neutral inorganic salts, and a surfactant.

Further, Japanese Patent Application Publication No. Sho [i+-87G59] discloses an aqueous suspension containing an organic peroxide, tricalcium phosphate, and a surfactant.

(Problems to be Solved by the Invention) However, the aqueous fJj suspensions described in these publications are 4. When 'i is dibenzoyl peroxide, which has a high specific gravity of organic peroxide of 1.33, there are several drawbacks as follows. Firstly, the storage stability is still insufficient and it easily separates into two layers and settles and solidifies.Secondly, it is dangerous to re-disperse what has settled and solidified because the explosive power of ID dibenzoyl oxide is strong. , and even if redispersed, it separates immediately.

As described above, aqueous suspensions according to the prior art have problems with storage stability and redispersibility, as described above.

Therefore, it is strongly desired that these properties be further improved in order to make them suitable for pumping.

(Another Means to Solve the Problem) In response to the above-mentioned request, the present inventors have conducted intensive research to develop an aqueous suspension of dibenzoyl peroxide that has excellent storage stability and redispersibility. It has been found that an aqueous suspension of dibenzoyl peroxide containing a specific amount of a specific polyhydric alcohol and a specific surfactant significantly improves the above-mentioned properties.

This invention was completed based on the above knowledge,
The gist is that in an aqueous suspension of dibenzoyl peroxide and its derivatives, (a) one or more types selected from the group consisting of 6-carbon monomers, their hydrogen reduction products, and 12-carbon dihydrogens; Polyhydric alcohol 10~65i1ji! ,
and (b) a nonionic surfactant with an HLB value of 10 or less and a nonionic surfactant with an HLB value of 10 or more, or a nonionic surfactant with an HLB value of 10 or less and an anionic surfactant. surfactant consisting of 0.001 to 10
The present invention relates to an aqueous suspension of dibenzoyl peroxide, characterized in that it contains fiiX.

In addition to dibenzoyl peroxide, peroxides to which this invention can be applied include nuclear-substituted dimethyl or monomethyl dibenzoyl peroxide such as p, p'-dimethyl dibenzoyl peroxide, and nuclear substituted dibenzoyl peroxide such as p, p'-dimethoxy dibenzoyl peroxide. Dimethoxy or monomethoxy dibenzoyl peroxide, p.

There are derivatives of dibenzoyl peroxide such as nuclear substituted dichloro such as p'-dichloro dibenzoyl peroxide or monomethyl dibenzoyl peroxide. Mixtures of these can also be used.

The amount of dibenzoyl peroxide and its derivatives used is usually 5 to 60 parts per liter of the entire aqueous suspension, preferably In to SO.
i [l l % There is.

If the amount used is too less than 5 weight X, it will be economically disadvantageous, and if it is too much more than 60 mHzN, the viscosity will become high and it will be inconvenient to handle.

The polyhydric alcohols used in this invention are monosaccharides with 6 carbon atoms, hydrogen-reduced products thereof, and bisaccharides with 12 carbon atoms. Examples include glucose and its hydrogen reduced products such as sorbitol, sorbitan, sorbose, dulcit, galactose, mannitol, fructose, mannose, and gulose. In addition, the disaccharides of J & prime number 12 include non-reducing disaccharides such as trehalose, intrehalose, sucrose, and isosaccharose, maltose,
Examples include reducing biaxes such as cellobiose, gentiobiose, melibiose, lactose, turanose, and sophorose.

Note that polyhydric alcohols with a small number of carbon atoms such as glycerin do not have sufficient redispersibility, and polyhydric alcohols with high molecular weight such as polysaccharides 1 such as starch have too high a viscosity to be practical.

Furthermore, among the polyhydric alcohols, sorbitol and sucrose are particularly preferred because they form highly concentrated aqueous solutions and are non-reducing. In addition, in the present invention, a mixture of two or more of the above polyhydric alcohols can also be used.

In this invention, the amount of polyhydric alcohol used is 10! [i
More than H 65mff1X or less, preferably 1
5 wounds ■ more than 60 frXmX or less.

In addition, if the amount of polyhydric alcohol used is less than 10mg, the storage stability will be insufficient, and 65fffiii:X
If it is more than that, it will be economically disadvantageous.

Next, we will explain the surfactant used in this invention.
I do it.

In this invention, in order to obtain an aqueous suspension having storage stability, low viscosity, and good redispersibility, a nonionic surfactant having an HLB value of 10 or less is added to the aqueous suspension containing the polyhydric alcohol. An ionic surfactant with an HLB value of 10 or more is added, and a surfactant consisting of a nonionic surfactant and an anionic surfactant with an HLB value of 1 or less is added to IO.

Examples of nonionic surfactants with an HLB value of 10 or more used in this invention include polyoxyethylene fatty acid esters such as polyoxyethylene stearate, polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, polyoxyethylene Examples include polyoxyethylene alkylphenol ethers such as nonylphenol ether, polyoxyethylene glycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan oleate, and shea fatty acid esters. Among these, polyoxyethylene alkylphenol ether is particularly preferred.

Examples of nonionic surfactants with HLB values of IO or less include sorbitan fatty acid esters containing mono-, sesqui-, and tri-isomers such as sorbitan oleate, glycerin fatty acid esters such as glycerin oleate, and propylene oleate. There are propylene glycol fatty acid esters such as. Among these, sorbitan fatty acid ester is preferred because it does not adversely affect the polymerization properties when polymerizing ethylenically unsaturated monomers.

Examples of anionic surfactants include sodium oleate, fatty acid salts such as castor oil, N-acylamino compounds, alkyl ether carboxylates, acylated peptides, alkyl sulfonates, and dodecylbenzenesulfonic acid. Alkylaryl sulfonates such as sodium, alkylnaphthalene sulfonates, derivatives of naphthalene sulfonates, sodium salts of β-naphthalene sulfonic acid formalin condensates, dialkyl sulfosuccinates, α-olefin sulfonates, N-acylsulfones acid salts, higher alcohol sulfate ester salts such as sodium 2-ethylhexyl sulfate and sodium cetyl sulfate, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylphenol ether sulfates, alkylamide sulfates, alkyl phosphate, alkyl ether phosphate,
Examples include polymeric surfactants such as alkyl allyl ether phosphoric acid and polycarboxylic acid. Among these, fatty acid salts and alcohol sulfate ester salts are preferred because they do not adversely affect the polymerization properties when polymerizing ethylenically unsaturated monomers.

In this invention, a nonionic surfactant with an HLB value of 10 or less, a nonionic surfactant with an HLB value of 10 or more,
Alternatively, a combination of a nonionic surfactant and an anionic surfactant with an HLB value of 10 or less may be used, and the proportion thereof varies depending on the type and purpose of the organic compound. As an example of the mixing ratio, a nonionic surfactant with an HLB value of 10 or less and an anionic surfactant are used at a ratio of 3:1.

The type of surfactant used in this invention is appropriately selected depending on desired viscosity and storage stability.

In addition, the amount of surfactant used in this invention is HLB
The combined amount of a nonionic surfactant with a value of 10 or less and a nonionic surfactant with an HLB value of 10 or less, or a nonionic surfactant with an HLB value of 10 or less and an anionic surfactant, or an aqueous suspension. The amount is 0.001 to 10% by weight in the suspension.

If the amount used in the aqueous suspension is less than 0.001 weight 2, there may be disadvantages such as insufficient improvement in storage stability;
If the amount is more than 01■, the effect of adding more than that will not improve. In other words, there are disadvantages such as being economically disadvantageous.

In addition, for the purpose of improving the storage stability of the aqueous suspension, a low molecular weight alcohol such as methyl alcohol or ethyl glycol may be used in addition to the polyhydric alcohol and surfactant.

Further, for the purpose of improving storage stability, a colloidal agent may be included in the aqueous suspension together with water.

Examples of the colloidal agent include commonly used water-soluble cellulose derivatives such as methylcellose and carboxymethylcellulose, and partially or completely latched polyvinyl.

The aqueous suspension of dibenzoyl peroxide of the present invention can be produced, for example, as follows. First, water and a polyhydric alcohol are added to a container, then a surfactant is added, and dibenzoyl peroxide is added after /Il, followed by thorough dispersion.

The equipment used to produce the aqueous suspension of dibenzoyl peroxide of this invention can be any known equipment, such as a paddle stirrer, a colloid mill, a high speed shear!
Equipment such as an ultrasonic homogenizer or a three-roll mill can be used.

In addition, the aqueous fJj p% of dibenzoyl peroxide of this invention
Examples of ethylenically unsaturated monomers that can be polymerized or copolymerized with a liquid include vinyl chloride, styrene, vinyl acetate, methacrylate, and acrylonitrile.

4. Most preferably styrene is used. In this case, the amount of the aqueous suspension of dibenzoyl peroxide used is within the usual usage range. The polymerization can be carried out by conventional methods.

(Effects of the Invention) According to the present invention, an aqueous suspension of dibenzoyl peroxide having excellent storage stability and redispersibility and low viscosity can be obtained.

Therefore, the aqueous suspension of dibenzoyl peroxide according to the present invention is first of all stable and therefore extremely easy to handle and transport; it does not become a hard cake even if it is separated into two layers by sedimentation; It has the advantage that it can be easily redispersed to form a stable aqueous suspension when redispersing substances.

(Example) Next, the present invention will be described with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1 to 6 and Comparative Examples 1 to 5 The compositions shown in Table 1 were manufactured by the following method.

A surfactant was added and dispersed in a homogeneous solution of ice, polyhydric alcohol, and protective colloid. Dibenzoyl peroxide or its derivative was added thereto with stirring. 15 more
After stirring for a minute, the mixture was homogenized using a homomixer to obtain an aqueous suspension of each dibenzoyl peroxide. The proportion of each component in Table 1 is double star %.

Comparative Example 1 is disclosed in Japanese Unexamined Patent Publication No. 51-125:102.

Comparative Example-2 is an aqueous suspension of dibenzoyl peroxide prepared according to the method described in Publication No. 57-5OIO85, and Comparative Example-3 is an aqueous suspension of dibenzoyl peroxide prepared according to the method described in JP-A No. 12-516 [i6]. .

Next, the following viscosity measurement, storage stability test, and redispersibility test were conducted using the aqueous suspensions of dibenzoyl peroxide obtained in Examples and Comparative Examples.

(Viscosity: 411 constant) The viscosity of the sample at 20° C. was determined at 311 constant (the unit is voids) using a B-type packing intensifier (manufactured by Tokyo Keiki Seisaku Pyr, rotation speed: 2011 PM).

(Storage Stability Test) The sample was stored in a glass container maintained at 20° C., and the change in appearance (the period until the water layer was divided into 5% or more) was used as a measure of storage stability.

(Redispersibility test) The sample that had been prepared for one month was redispersed using a paddle stirrer (temperature 25°C, rotation speed 80011PM, stirring time 1
0 minutes). After storing it in a static dish for 24 hours, the concentration of per-drunken dibenzoyl at 10% from the top layer and at 102 from the bottom layer is measured by iodometry. Next, we classified the quantity dispersion as good or bad based on the method.

◎ mark There is a difference of less than 1% between the upper and lower layers ○ mark there is a difference of 1 to 1 lot between the upper and lower parts × mark The above test results solidify at the bottom of the container and cannot be easily and uniformly dispersed. It is shown in Table-2. Although the storage stability of the aqueous suspension of Comparative Example 3 is relatively good, it is difficult to handle due to the viscosity of 14%. From the results of more than 6 experiments, the aqueous suspension of the present invention shown in the Examples was shown as a Comparative Example. When comparing the viscosity, storage stability, and redispersibility in a comprehensive manner, it is clear that it has far superior properties in practical terms.

In addition, suspension polymerization of styrene was carried out using both the aqueous suspension of dibenzoyl peroxide prepared in Example 141 immediately after dispersion and that after redispersion. The results were also the same as when dibenzoyl was used alone.

Table-2

Claims (1)

[Scope of Claims] An aqueous suspension of dibenzoyl peroxide and its derivatives, comprising: (a) a monosaccharide having 6 carbon atoms, a hydrogen reduction product thereof, and a 1-carbon monosaccharide;
(b) a nonionic surfactant with an HLB value of 10 or less and a nonionic surfactant with an HLB value of 10 or more; surfactant or HL
An aqueous suspension of dibenzoyl peroxide, characterized in that it contains 0.001 to 10% by weight of a surfactant consisting of a nonionic surfactant and an anionic surfactant having a B value of 10 or less.