JPS62109811A - Production of highly heat-resistant methyl methacrylate resin - Google Patents

Abstract

PURPOSE:The titled resin having high heat resistance, improved transparency, etc., obtained by copolymerizing methyl methacrylate with N-cyclo hexylmaleimide and a vinyl unsaturated in a specific ratio in the presence of a radical polymerization initiator. CONSTITUTION:(A) 40-99wt%, preferably 55-98wt% methyl methacrylate is copolymerized with (B) 1-60wt%, preferably 2-45wt% cyclohexylmaleimide and (C) 0-20wt%, preferably 0-10wt% vinyl unsaturated compound (e.g., alpha- methylstyrene, etc.,) in the presence of a radical polymerization initiator, to give the aimed resin. EFFECT:Having improved heat stability and processing properties.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for producing methyl methacrylate resin,
More specifically, the present invention relates to a method for producing a highly heat-resistant methyl methacrylate resin.

<Prior art and problems> Methyl methacrylate resin is light, strong, has excellent transparency, has good weather resistance, water resistance, and processability, and is relatively inexpensive, so it can be used in various applications. Widely used for molding materials, plate materials, etc.

However, methyl methacrylate resin has the disadvantage that it cannot be used in areas subject to high heat because it does not have sufficient heat resistance6. Conventionally, α-methylstyrene has been copolymerized to improve heat resistance, but this is not always effective. Problems arise, such as insufficient hardness and deterioration of molding processability.

On the other hand, a method in which N-phenylmaleide is used as a copolymerization additive has been proposed for improving heat resistance, but this method also has drawbacks such as coloring and is not a satisfactory method.

<Object of the Invention> An object of the present invention is to provide a method for producing a methyl methacrylate resin having high heat resistance and excellent transparency.

<Means for solving the problems> According to the present invention, 40 to 99% by weight of methyl methacrylate
and 1 to 60% by weight of N-cyclohexylmaleimide,
A method for producing a highly heat-resistant methyl methacrylate resin is provided, which comprises copolymerizing O to 20% by weight of a vinyl unsaturated compound in the presence of a radical polymerization initiator.

The present invention will be explained in more detail below.

In the present invention, 40-99% by weight, preferably 55-98% by weight of methyl methacrylate and 1-60% by weight, preferably 2-45% by weight of N-cyclohexylmaleimide are copolymerized as essential monomer components. N-cyclohexylmaleimide has high polymerizability, easily copolymerizes with methyl methacrylate, imparts heat resistance to the copolymer, and has no coloring property, so it is useful for modifying methyl methacrylate-based resins. . The amount of N-cyclohexylmaleimide is 1
If it is less than 60% by weight, the effect of improving heat resistance will not be exhibited, and if it exceeds 60% by weight, the original physical properties of methyl methacrylate resin such as weather resistance, water resistance, processability, etc. will be lost.

In the present invention, 0 to 20% by weight of a vinyl unsaturated compound that can be copolymerized with methyl methacrylate and N-cyclohexylmaleimide is further used as a third component.

Preferably, 0 to 10% by weight may be added and copolymerized. Examples of such vinyl unsaturated compounds include styrene,
Aromatic vinyl compounds such as α-methylstyrene, acrylic esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, etc., and methacrylic esters other than methyl methacrylate,
For example, ethyl methacrylate, propyl methacrylate,
Examples include butyl methacrylate. By further copolymerizing the third component, it is possible to balance two properties of the resulting methyl methacrylate system, such as processability, impact resistance, and thermal stability. If the proportion of the vinyl unsaturated compound exceeds 20% by weight, the original properties of the methyl methacrylate resin will be lost, which is not preferable.

In the present invention, the above monomer components are copolymerized in the presence of a radical polymerization initiator. Examples of the radical polymerization initiator include known ones such as benzoyl peroxide, lauroyl peroxide, t-butylperoxy-2-ethylhexanoate, persulfate, hydrogen peroxide, and azobisisobutyronitrile. . Copolymerization can be carried out by known radical polymerization methods such as bulk polymerization, solution polymerization, and emulsion polymerization. Copolymerization is usually carried out at 40 to 150°C for about 4 to 24 hours.

Note that additives such as fillers, pigments, stabilizers, and plasticizers can be added as necessary.

<Effects of the Invention> The methyl methacrylate resin of the present invention has improved heat resistance and significantly improved thermal stability measured by 9 decomposition temperatures, etc., without losing transparency, which is the original characteristic of methyl methacrylate resin. , there is no change in workability or increase in brittleness, so it has great practical value.

<Example> The present invention will be explained below with reference to Examples and Comparative Examples.

Parts and percentages in the examples are by weight.

Collect 96 parts of methyl methacrylate (MMA), 4 parts of N-cyclohexylmaleimide (CHMI), 0.4 parts of azobisisobutyronitrile, and 180 parts of benzene into a polymerization tube, and connect this to a vacuum line. did. Thereafter, the polymerization tube was cooled using liquid N2 and vacuum (I
After that, the pressure was increased to I Torr with dry N2. After repeating these operations three times, Yuko's polymerization tube was sealed in a thermostat kept at 60°C while shaking and stirring. Polymerization was carried out over 24 hours6
After the polymerization was completed, the tube was opened and the contents were poured into a large amount of methanol to precipitate the polymer. The precipitate was separated in a furnace, thoroughly washed with methanol, dissolved in a small amount of tetrahydrofuran, and then poured into methanol again for precipitation. This operation was repeated three times to purify the polymer, which was then dried under reduced pressure to obtain 87 g of the polymer.6 The obtained product was a white powder, but when molded into a thin plate, it was colorless and transparent. The polymer powder was compression molded at 170° C. to form a test piece with a thickness of 3 nn, and various tests shown in Table 1 were conducted on the test piece. The results are shown in Table 1.

Example 1 except that the amount of CHMI was changed as shown in Table 1.
A polymer was obtained in the same manner as above. Table 1 shows its physical properties.

A polymer was obtained in the same manner as in Example 1 except that benzoyl peroxide was used instead of azobisisobutyronitrile. The results are shown in Table 1.

Comparative Example 1 A polymer was obtained in the same manner as in Example 1 except that 100 parts of MMA and 1 part of CHMIO were used. The results are shown in Table 1.

A polymer was obtained in the same manner as in Example 1 using 90 parts of MMA and 10 parts of N-phenylmaleimide. Table 1 shows the results.
Shown below.

85 parts of MMA, 1 part of CHMIIO, 5 parts of butyl acrylate, butylperoxy-2-ethylhexanoate (
Copolymerization was carried out according to Example 1 using 0.5 part of PO). Table 2 shows the physical properties of the obtained polymer.

Example 8 Copolymerization was carried out according to Example 1 using 35 parts of MMA, parts of CHMIIO, 5 parts of α-methylene/L/styrene, and 5 parts of POO. Table 2 shows the physical properties of the polymer.

Claims (1)

[Claims] A polymeric polymer characterized by copolymerizing 40 to 99% by weight of methyl methacrylate, 1 to 60% by weight of N-cyclohexylmaleimide, and 0 to 20% by weight of a vinyl unsaturated compound in the presence of a radical polymerization initiator. A method for producing heat-resistant methyl methacrylate resin.