JP2855780B2 - Polymerization method of vinyl monomer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a vinyl monomer alone or a mixture of a vinyl monomer and a copolymerizable vinyl monomer in the presence of a specific dye. The present invention relates to a method for polymerizing a vinyl monomer, in which a specific polymerization initiator is used at the time of polymerization to complete the polymerization without discoloring the dye.

[Conventional technology]

Colored vinyl polymers are widely used as sheet materials or molding materials in many fields such as lighting parts, automobile parts, electric equipment parts, household goods and the like.

Conventionally, two methods have been employed to produce a vinyl polymer molded article colored with a dye.

One is a method in which a vinyl polymer is produced, and then a dye is kneaded into the vinyl polymer and molded.

Another method is a method in which a vinyl monomer in which a dye has been dissolved in advance is polymerized and molded.

[Problems to be solved by the invention]

However, the former method is a generally used method because there are no other restrictions on the type of dye or the like, but the dispersion of the dye tends to be non-uniform, and particularly for the production of molded products that require transparency. Had a problem.

On the other hand, the latter method does not have such a problem, but has a problem that the dye is chemically changed by a side reaction of polymerization, and as a result, discoloration or fading occurs. In particular, anthraquinone dyes were remarkably discolored when a general organic peroxide was used as a polymerization initiator, and could not be used industrially. Therefore, conventionally, an azo-based polymerization initiator has been used.

However, there is a problem that the azo-based polymerization initiator itself tends to cause coloration, and cannot be used in certain applications in view of the toxicity of its decomposition product.

An object of the present invention is to solve the above-mentioned problems and, when polymerizing a vinyl monomer in the coexistence of an anthraquinone-based dye, can complete the polymerization without changing the color tone of the anthraquinone-based dye. To provide a method for polymerizing vinyl monomers.

[Means for solving the problem]

The present inventors have studied the problems of the above-mentioned conventional methods over a long period of time, and as a result, have found a method of completing the polymerization without discoloring the dye by using a specific polymerization initiator, and completed the present invention.

That is, in the present invention, when a vinyl monomer alone or a mixture of a vinyl monomer and a vinyl monomer copolymerizable therewith is polymerized in the presence of an anthraquinone dye, a peroxyester type organic compound is used as a polymerization initiator. The gist of the invention is a method for polymerizing a vinyl monomer, which comprises using a peroxide.

 Next, each component of the present invention will be described.

Examples of the vinyl monomer used in the present invention or a vinyl monomer copolymerizable therewith include methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, and methyl acrylate. Acrylates such as ethyl acrylate, butyl acrylate, octyl acrylate, styrene,
Methylstyrene, t-butylstyrene, divinylbenzene, acrylonitrile, methacrylonitrile, phenylmaleimide, cyclohexylmaleimide, vinyl acetate and the like are used.

Further, in addition to these monomers, various chain transfer agents may be added for the purpose of controlling the molecular weight. Examples of the chain transfer agent include mercaptans such as n-octyl mercaptan and n-dodecyl mercaptan, α-methylstyrene dimer, terpinolene and the like.

As the anthraquinone dye used in the present invention,
For example, 1-amino-2-bromo-4-p-tolylaminoanthraquinone [color index number (hereinafter C.I.
62100], 1,4-bis (isopropylamino) anthraquinone (CI61551), 1,4-diaminoanthraquinone (CI61100), 1,4-di (phenylamino)
Anthraquinone, 1,4-di (p-tolylamino) anthraquinone (CI61565), 1,4-di (pentylamino) anthraquinone (CI61555), 1-methylaminoanthraquinone (CI60505), 1.5-di (p-tolylamino)
Anthraquinone (CI61705), 1-methylamino-4
-P-tolylaminoanthraquinone (CI61525) and the like.

The amount of the dye used varies depending on the use of the polymer, but is generally about 0.001 to 0.1% by weight.

Specific examples of the peroxyester type polymerization initiator used in the present invention include t-butyl peroxypivalate, t-butylperoxyneohexanoate, t-butylperoxyisobutyrate, and t-butylperoxy-2. -Ethylhexanoate, t-butylperoxy neodecanoate, t-amyl peroxypivalate, t
-Amyl peroxy neohexanoate, t-amyl peroxyisobutyrate, t-amyl peroxy-2-
Ethyl hexanoate, t-amyl peroxy neodecanoate, t-hexyl peroxy pivalate, t-hexyl peroxy neohexanoate, t-hexyl peroxyisobutyrate, t-hexyl peroxy-2
-Ethylhexanoate, t-hexylperoxy neotecanoate, t-octylperoxypivalate, t
-Octylperoxyneohexanoate, t-octylperoxyisobutyrate, t-octylperoxy-2-ethylhexanoate, t-octylperoxyneodecanoate, and the like.

The amount of the polymerization initiator to be added varies depending on the polymerization temperature, the type of the monomer used for the polymerization or the combination thereof, but is generally 0.001 to 1 part by weight in terms of a pure product with respect to the charged amount of the monomer of 100 parts by weight. , Preferably 0.01 to 0.1 part by weight. The amount
If the amount is less than 0.001 part by weight, the polymerization rate tends to be slow,
If it exceeds 1 part by weight, it may be difficult to control the polymerization rate. The polymerization method used in the present invention is a usual bulk polymerization method or suspension polymerization method, and the polymerization temperature is generally 40 to 130 ° C, preferably 50 to 100 ° C. The polymerization is carried out at a constant temperature or at a relatively low temperature at the beginning of the polymerization, and the temperature is raised stepwise as the polymerization proceeds. Further, a method of performing polymerization in the latter half of the polymerization is used. In the latter half of the polymerization, 10
The treatment may be performed at a high temperature of 0 ° C. or more.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples. In addition, the abbreviation of the polymerization initiator used in each example means the following compounds.

Bu-PV; t-butylperoxypivalate Bu-NH; t-butylperoxyneohexanoate Bu-IB; t-butylperoxyisobutyrate Bu-O; t-butylperoxy-2-ethylhexanoate Bu- ND; t-butyl peroxy neodecanoate Am-PV; t-amyl peroxy neodecanoate Am-ND; t-amyl peroxy neodecanoate Hx-PV; t-hexyl peroxypivalate Hx-O; t-hexyl peroxy -2-Ethylhexanoate Hx-ND; t-hexylperoxyneodecanoate Oc-PV; t-octylperoxypivalate Oc-O; t-octylperoxy-2-ethylhexanoate Oc-ND; Octyl peroxy neodecanoate BPO; benzoyl peroxide LPD; lauroyl peroxide OPP; di (2-ethylhexyl) peroxydi Boneto The dye used was expressed in all CI.

(Examples 1 to 13 and Comparative Examples 1 to 5) 10 g of methyl methacrylate in a glass ampoule having a capacity of 20 ml
And the polymerization initiator shown in Table 1 with respect to 1 kg of vinyl monomer.
0.002 mol and 0.1 g (0.01% by weight) of the dye were added.
The ampoule was degassed under vacuum, melted and sealed. It was polymerized in a constant temperature oil bath at 70 ° C. for 5 hours. The color before and after the polymerization was visually observed. Each result is
The results are shown in Table 3.

As apparent from Tables 1 to 3, in the polymerization of methyl methacrylate, for Examples 1 to 13 using a peroxyester type polymerization initiator, there was no discoloration of the dye after the polymerization, whereas the polymerization initiator When using bezoyl peroxide (Comparative Examples 1 and 2), when using lauroyl peroxide (Comparative Examples 3 and 4) and di (2-ethylhexyl)
In the case where peroxydicarbonate was used (Comparative Example 5), it was found that the dye changed color after polymerization in all cases. Therefore, the colored polymers obtained in Examples 1 to 13 are suitable as sheet materials and molding materials used for automobile parts, electric equipment parts and the like.

(Examples 14 to 21 and Comparative Examples 6 to 10) Using the same ampoule as in Example 1, 10 g of styrene and
The polymerization initiators shown in Tables and Table 5 were added at a ratio of 0.005 mol and 0.1 g (0.01% by weight) of the dye to 1 kg of the vinyl monomer. Thereafter, polymerization was performed under the same conditions as in Examples 1 to 13. Then, the color before and after the polymerization was observed. The results are shown in Tables 4 and 5.

As is clear from Tables 4 and 5, in Examples 14 to 21 using a peroxyester type polymerization initiator in the polymerization of styrene, there was no discoloration of the dye after the polymerization. In the case of using benzoyl peroxide as an agent (Comparative Examples 6 and 7), the case of using lauroyl peroxide (Comparative Examples 8 and 9) and the case of using di (2-ethylhexylperoxy) dicarbonate (Comparative Example 10), In each case, it is found that the color of the dye changes after polymerization.

(Example 22) In Example 1, instead of 10 g of methyl methacrylate, 9.5 g of methyl methacrylate and 0.5 g of methyl acrylate were used.
Polymerization was carried out in the same manner as in Example 1 except that 5 g was used. As a result, the blue color before the polymerization did not change at all even after the polymerization.

(Comparative Example 11) Polymerization was carried out in the same manner as in Example 22, except that 0.048% by weight of BPO was used instead of Bu-PV as the polymerization initiator. As a result, it was blue before polymerization,
After the polymerization, the color changed to dark blue.

Example 23 Polymerization was carried out in the same manner as in Example 8, except that 7 g of methyl methacrylate and 3 g of N-cyclohexylmaleimide were used instead of 10 g of methyl methacrylate. As a result, the green color before the polymerization did not change color even after the polymerization.

(Comparative Example 12) Polymerization was carried out in the same manner as in Example 23, except that 0.080% by weight of LPO was used instead of Hx-PV as the polymerization starter. As a result, the color was green before the polymerization, but changed to dark green after the polymerization.

As is clear from the results of Example 22 and Comparative Example 11 and Example 23 and Comparative Example 12, even in the case of the mixture of the vinyl monomers, only the one using the peroxyester type polymerization initiator, the anthraquinone dye was used. It turns out that there is no discoloration.

〔The invention's effect〕

According to the method for polymerizing a vinyl monomer of the present invention, by using a specific polymerization initiator, the polymerization can be completed without changing the color tone of the anthraquinone dye, and there is no toxicity problem. To play.

Claims (1)

(57) [Claims] When a vinyl monomer alone or a mixture of a vinyl monomer and a vinyl monomer copolymerizable therewith is polymerized in the presence of an anthraquinone dye, a peroxyester type organic compound is used as a polymerization initiator. A method for polymerizing a vinyl monomer, comprising using a peroxide.