JPH0559131A - Production of copolymer - Google Patents

Abstract

PURPOSE:To simply and profitably obtain in an industrial scale the subject copolymer having excellent transparency by dissolving an N-alkylmaleimide in a copolymerizable monomer consisting of an olefin and subsequently subjecting the solution to a bulk precipitation polymerization in a solvent-free state. CONSTITUTION:(A) An N-alkylmaleimide such as N-methylmaleimide is dissolved in (B) a copolymerizable monomer consisting of an olefin such as isobutene and subsequently subjected the resulting solution to a bulk precipitation polymerization in the presence of a radical polymerization initiator such as benzoylperoxide in a solvent-free state preferably at 40-150 deg.C for approximately 0.1-50hr (preferably 1-20hr) to obtain the objective copolymer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an N-alkylmaleimide-olefin copolymer having excellent transparency.

[0002]

2. Description of the Related Art Maleimide polymers have long been studied as a polymer material having high heat resistance centering on phenylmaleimide. However, when the number of maleimide units increases, the resulting polymer becomes extremely brittle, so that the heat resistance of ABS is high. It is only used for the purpose of adding about 10% or so as a modifier. Further, since the produced polymer is easily colored, it becomes a big problem depending on the application.

Recently, cyclohexylmaleimide has been investigated as a heat resistance improver for acrylic resins or vinyl chloride resins. This monomer is characterized by being less likely to be colored than phenylmaleimide, but when the number of maleimide units increases, there is a problem that the mechanical properties of the polymer deteriorate, or there is a problem such as coloring, and it is usually about 10%. Is used for.

Alkylmaleimide and a specific olefin-based copolymer have high heat resistance and practical mechanical properties and are interesting materials, but there are few studies on the manufacturing process thereof.

Conventionally, suspension polymerization, emulsion polymerization, solution polymerization, bulk polymerization and the like are known as methods for polymerizing vinyl monomers, and suspension polymerization and emulsion polymerization are often used industrially. It is used.

However, many maleimide monomers are solid at room temperature and many olefins are gaseous, so that there are many difficulties in using the usual suspension polymerization method or emulsion polymerization method. Further, in these polymerization methods, since a dispersion stabilizer and an emulsifier are used, the quality of the transparent polymer is deteriorated. Further, the solution polymerization method requires a step of separating and recovering a solvent from the polymer, which is a problem in that it is a complicated process.

[0007]

An object of the present invention is to provide a method for producing a maleimide-olefin copolymer, and further a simple and industrially advantageous method for producing a maleimide-olefin copolymer. To provide.

[0008]

DISCLOSURE OF THE INVENTION As a result of intensive studies in view of this problem, the present inventors have found that N-alkylmaleimides are dissolved in olefins and polymerization is carried out without using a medium such as a solvent. The present inventors have found that the polymerization process satisfies the above-mentioned object and completed the present invention.

That is, according to the present invention, in producing an alkylmaleimide-olefin copolymer by radically copolymerizing an alkylmaleimide with an olefin, a maleimide is dissolved in an olefin and a medium such as a solvent is used. Maleimide, characterized in that the polymerization is carried out without
The present invention relates to a method for producing an olefin-based copolymer.

More specifically, in the production method of the present invention, the monomer mixture is uniform, but the produced polymer is insoluble in the monomer mixture, and the polymer is deposited as the polymerization proceeds, so-called precipitation. Regarding the polymerization process, since the production method of the present invention does not use a polymerization medium such as a solvent, a polymer can be obtained by simply removing olefins, which are often gaseous at room temperature and pressure. It is a simple process.

Further, by using such a production method, a high-purity polymer containing no impurities such as a dispersant, an emulsifier, a solvent can be obtained.

The use ratio of the alkylmaleimides and olefins used in the present invention is 1.5 moles or more of olefins per mole of maleimides in order to make the polymerization reaction proceed stably. It is preferable to use at least a molar amount.

Here, as the N-alkylmaleimides, N-methylmaleimide, N-ethylmaleimide, N-
n-propylmaleimide, N-i-propylmaleimide, Nn-butylmaleimide, N-i-butylmaleimide, Ns-butylmaleimide, Nt-butylmaleimide, Nn-pentylmaleimide, Nn -Hexylmaleimide, N-n-heptylmaleimide, Nn-
Octyl maleimide, N-lauryl maleimide, N-stearyl maleimide, N-cyclopropyl maleimide,
Examples thereof include N-cyclobutylmaleimide and N-cyclohexylmaleimide, and these can be used alone or in combination of two or more.

As olefins, isobutene, 2-methyl-1-butene, 2-methyl-1-pentene, 2-methyl-1-hexene, 1-methyl-1-heptene, 1-
2-position substituted olefins such as isooctene, 2-methyl-1-octene, 2-ethyl-1-pentene, 2-methyl-2-butene, 2-methyl-2-pentene and 2-methyl-2-hexene are preferable, These can be used alone or in combination of two or more.

As the radical polymerization initiator used in the production method of the present invention, various initiators can be used, but usually, benzoylperoxide, laurylperoxide, octanoylperoxide, acetylperoxide,
Di-t-butylperoxide, t-butylcumylper
Oxide, dicumylper oxide, t-butylper
Oxyacetate, t-butylperoxybenzoate
, Organic peroxides such as per-butyl neodecaneate, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-butyronitrile),
2,2'-azobisisobutyronitrile, dimethyl-
Examples of the azo initiator include 2,2'-azobisisobutyrate and 1,1'-azobis (cyclohexane-1-carbonitrile). These initiators may be used alone or in combination of two or more.

The amount of the initiator used was 0.
0001-0.1 mol%, preferably 0.001-0.
It is 05 mol%, and the catalyst may be added all at the initial stage of the polymerization, or may be dividedly added during the polymerization.

The polymerization temperature can be appropriately set according to the decomposition temperature of the initiator, but it is generally from 40 ° C to 150 ° C.
It is preferable to carry out in the range of. The polymerization temperature may be constant throughout the reaction, or the temperature may be raised or lowered continuously or stepwise.

The polymerization time is not particularly limited, but is 0.1-5.
It is 0 hours, preferably 1 to 20 hours.

If necessary, a chain transfer agent such as alkyl mercaptan may be added. Further, a hindered phenol type or phosphorus type antioxidant may be added at the beginning of the polymerization, during the polymerization or after the polymerization.

If necessary, other vinyl type monomers may be copolymerized within the range not impairing the object of the present invention. Other vinyl monomers include styrene,
α-methylstyrene, vinyltoluene, 1,3-butadiene, isoprene and their halogen-substituted derivatives,
Methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, etc. Acrylic acid esters, vinyl acetate, vinyl benzoate and other vinyl esters, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether,
One or more compounds selected from vinyl ethers such as butyl vinyl ether, vinyl chloride, vinylidene chloride, maleic anhydride, N-phenylmaleimide, N-carboxyphenylmaleimide and acrylonitrile.

The production method of the present invention can be carried out batchwise or continuously. The material of the reactor is not particularly limited, but it can be selected in consideration of the influence of the residual metal in the polymer, the scale and the like. Further, the reactor can be subjected to a scale preventive treatment such as glass lining.

The stirring is also not particularly limited, and a usual anchor type, spiral type, blur-margin type stirring blade or the like can be used. The stirring speed is usually 50 to 2000 rpm.

The maleimide-olefin copolymer obtained by the production method of the present invention comprises a maleimide repeating unit and an olefin repeating unit, and the maleimide unit is 30 to 98 mol%, preferably 50 to 75 mol% of the whole. Yes, gel permeation chromatography
The weight average molecular weight determined by (GPC) in terms of polystyrene is 1 × 10 ³ to 1 × 10 ⁷ , preferably 1 × 10 ^4.
It is desirable that it is ˜1 × 10 ⁶ .

Further, the maleimide-olefin copolymer obtained by the production method of the present invention precipitates as powder as the polymerization proceeds, but the average particle size of the precipitate is 1000 μm. Or less, preferably 100 to
It is 700 μm, and more preferably 200 to 500 μm.

The maleimide-olefin copolymer thus obtained has excellent transparency and can be used for various optical materials, sheets, films and the like.

[0026]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the examples.

The molecular weight of the produced polymer is GPC (Tosoh
It was determined by polystyrene conversion using HLC-802A manufactured by Co., Ltd.

The light transmittance was measured according to ASTM 1746.

The average particle size of the produced polymer (powder) is
The measurement was performed using a tap type shaker (manufactured by Tanaka Chemical Machinery Co., Ltd.).

Example 1 33.3 g of N-methylmaleimide was added to a 1-liter autoclave equipped with an anchor type stirrer, a nitrogen introducing tube, a thermometer and a degassing tube.
And 2,2′-azobisisobutyronitrile (AIB
N) 0.5 g was charged and after nitrogen substitution was performed, 380 g of isobutene was charged and the reaction was carried out at a stirring speed of 500 rpm and 60 ° C. for 10 hours. After the reaction was completed, the excess charged isobutene was discharged to the outside of the autoclave, and polymer powder 5
0.1 g was obtained.

Elemental analysis results of the obtained polymer (C; 6
4.7 wt%, H; 7.8 wt%, N; 8.4 wt%)
Therefore, the maleimide unit in the produced polymer was 50 mol%. The obtained polymer has a molecular weight (Mw) of 3.0 × 1.
0 ⁵ , glass transition temperature (Tg) = 154 ° C., decomposition temperature (Td) = 397 ° C., light transmittance 92%.

Example 2 Polymerization was carried out in the same manner as in Example 1 except that 37.5 g of N-ethylmaleimide was used to obtain 54.3 g of a polymer.

From the results of elemental analysis of the obtained polymer, the amount of maleimide units in the produced polymer was 50 mol%. The obtained polymer has a molecular weight (Mw) of 3.2 × 1.
0 ⁵ , Tg = 126 ° C., Td = 397 ° C., light transmittance 9
It was 2%.

[0034]

According to the production method of the present invention, a maleimide-olefin copolymer excellent in optical properties such as transparency can be efficiently produced by simple reaction and post-treatment. In particular, it can be used in a wide range of applications such as various optical elements and lighting parts.

Claims (1)

[Claims] 1. When radically copolymerizing N-alkylmaleimides and olefins to produce an N-alkylmaleimide-olefin-based copolymer, N-alkylmaleimides are dissolved in olefins as a copolymerization monomer. And a bulk precipitation polymerization process in which the polymerization is carried out without using a medium such as a solvent. A method for producing a maleimide-olefin copolymer.