JPH09151218A - Raw material for preparing heat resistant resin and heat resistant resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a material composed mainly of N-cyclohexyl maleimide which enables the manufacture of a N-cyclohexyl maleimide resin excellent in transparency, heat resistance and, moreover, low tinting, and such resin obtd. from the material. SOLUTION: This material is composed mainly of N-cyclohexyl maleimide contg. 0.001-1wt.% cyclohexyl aminosuccinic anhydride. This heat resistant resin is obtd. by polymerizing the material with at least one monomer which can copolymerize therewith.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a raw material for producing a heat-resistant resin, and a heat-resistant resin obtained by using the above-mentioned raw material, which has excellent heat resistance and appearance and is less colored.

[0002]

BACKGROUND OF THE INVENTION Methacrylic resin containing methyl methacrylate as a main component has excellent weather resistance and optical properties, and has a relatively well-balanced mechanical, thermal and molding processability. Therefore, it is used in many fields such as automobile parts, electric equipment parts, nameplates, signboards, lighting covers, decorative articles, and miscellaneous goods articles by taking advantage of these properties. However, the heat resistance is not always sufficient, and the use thereof is limited in the field where shape stability at high temperature is required, so that improvement of the heat resistance is strongly demanded.

Many proposals have already been made for improving the heat resistance of methacrylic resins, for example, a method of copolymerizing methyl methacrylate and N-arylmaleic acid imide (Japanese Patent Publication No. 43-9753). A method of blending a copolymer of methyl methacrylate, α-methylstyrene and maleic anhydride with a methyl methacrylate copolymer (JP-A-59-122536).

Further, as a method for providing a methacrylic resin which is transparent and has reduced coloration while improving heat resistance, a method in which methyl methacrylate and N-cyclohexylmaleimide are copolymerized in a specific range (Japanese Patent Laid-Open Publication No. 1988-242, 1988). 62-
156115, JP-A-62-177009), a method of copolymerizing methyl methacrylate and N-cyclohexylmaleimide, and the like to reduce the amount of raw material monomers remaining in the resulting copolymer (JP-A-2006-176242). 62-1126
No. 12) are known.

By copolymerizing methyl methacrylate and N-cyclohexylmaleimide according to these methods, improvement in heat resistance, transparency and colorability of methacrylic resin can be solved to some extent.

However, in order to obtain a methacrylic resin having more excellent heat resistance, it is necessary to increase the N-cyclohexylmaleimide unit in the resin, but the methacrylic resin obtained by increasing the N-cyclohexylmaleimide unit is colored. There is a problem that (yellowing) easily occurs.

The coloring of such a resin product is generally accepted in N-cyclohexylmaleimide type resins using N-cyclohexylmaleimide as a starting material. However, since there is a strong demand for reduction of coloring depending on the application of the resin product, development of a heat-resistant N-cyclohexylmaleimide-based resin with reduced coloring (in the present invention, this is referred to as “low coloring”) Was wanted.

[0008]

DISCLOSURE OF THE INVENTION The present invention is directed to the production of a low-coloring heat-resistant resin, particularly an N-cyclohexylmaleimide heat-resistant resin which is excellent in appearance such as transparency and heat resistance and has low colorability. It is an object to provide a raw material for producing a heat-resistant resin that enables the production.

Further, the present invention is a heat-resistant resin obtained by using the above-mentioned raw materials, particularly excellent in appearance such as transparency and heat resistance,
Further, it is an object of the present invention to provide an N-cyclohexylmaleimide heat-resistant resin having a low coloring property.

[0010]

DISCLOSURE OF THE INVENTION The present inventors have studied the coloring of N-cyclohexylmaleimide heat-resistant resin, and found that cyclohexylaminosuccinic anhydride, which is an impurity present in N-cyclohexylmaleimide as a starting material. Was determined to be a coloring-causing substance, and the present invention was completed based on this finding.

That is, the raw material for producing the heat-resistant resin of the present invention contains N-cyclohexylmaleimide as a main component and has a cyclohexylaminosuccinic anhydride content of 0.001-1.
% (Vs. N-cyclohexylmaleimide).

The heat-resistant resin of the present invention is characterized by being obtained by copolymerizing the above-mentioned raw material and at least one monomer copolymerizable therewith, and the above-mentioned heat-resistant resin The yellowness (YI) in 2 or less, or the yellowness (YIsol.) In the solution is 3 or less, preferably 2 or less.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A raw material for producing a heat-resistant resin of the present invention contains N-cyclohexylmaleimide as a main component and has a cyclohexylaminosuccinic anhydride content of 0.001 to 1% by weight (vs. N-cyclohexylmaleimide). There is something.

N-cyclohexylmaleimide is a known substance, and its production method is also well known. Specifically, for example, it can be easily obtained by ring closure of N-cyclohexylmaleamic acid obtained by reacting maleic anhydride with cyclohexylamine.

However, it has not been known so far that cyclohexylaminosuccinic anhydride is contained as an impurity in the N-cyclohexylmaleimide thus obtained, and this cyclohexylaminosuccinic anhydride is N-cyclohexylaminosuccinic anhydride. It was discovered by the present inventors for the first time that it is a substance causing coloration of a cyclohexylmaleimide heat-resistant resin. This cyclohexylamino succinic anhydride has the following structural formula and is considered to be a by-product in the production process of N-cyclohexylmaleimide.

[0016]

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The raw material for producing the heat-resistant resin of the present invention is N-
Cyclohexylmaleimide as the main component, and the cyclohexylaminosuccinic anhydride content (vs. N-cyclohexylmaleimide, the same hereinafter) is adjusted to 0.001 to 1% by weight, more preferably 0.001 to 0.5% by weight. It will be.

If the cyclohexylaminosuccinic anhydride content exceeds 1% by weight, the obtained N-cyclohexylmaleimide heat-resistant resin is colored (see Comparative Examples 1 and 2). On the other hand, even if the cyclohexylaminosuccinic anhydride content is less than 0.001% by weight, no further reduction in coloration corresponding to it is observed, and considering the costs associated with operations such as distillation to remove cyclohexylaminosuccinic anhydride. A cyclohexylaminosuccinic anhydride content of at least 0.001% by weight is sufficient.

The raw material having a cyclohexylamino succinic anhydride content of 0.001 to 1% by weight is a crude N after the reaction.
-A method such as distillation of a raw material mainly containing cyclohexylmaleimide, recrystallization using a solvent such as acetone,
It is easily obtained by repeating those operations.

The cyclohexylamino succinic anhydride content in the present invention was measured by the following method. Cyclohexylamino succinic anhydride content was measured using high performance chromatography (LC-10A) manufactured by Shimadzu Corporation according to the method described in the section of Examples below.

The heat resistant resin referred to in the present invention means a glass transition temperature of 120 ° C. or higher and a yellowness index (YI) of 2 or less measured by the following method, or a yellowness index (YIsol. ) Is 3 or less, preferably 2 or less, and more preferably 1 or less.

Yellowness (YI, YIsol.) A polymer plate made of the heat-resistant resin of the present invention and having a thickness of 3.0 mm, which is obtained according to the cast polymerization method described in Example 1 below, and Example 3 described below. A 3.0 mm-thick copolymer molded article made of the heat-resistant resin of the present invention obtained according to the method described above, using a color difference meter (Σ80 manufactured by Nippon Denshoku Industries Co., Ltd.) and having a yellowness degree according to JIS-K-7103. (Y
I) was measured.

A 15 wt% chloroform solution of a copolymer pellet of the heat-resistant resin of the present invention obtained according to the method described in Example 3 below was prepared, and the chloroform solution was placed in a glass cell having a thickness of 10 mm. JIS-K-
7103, the transmitted light was used to measure the tristimulus values, and the yellowness in the solution (YI
sol. ) Was measured.

Examples of the monomer copolymerizable with the raw material containing N-cyclohexylmaleimide as a main component used in the production of the low-coloring heat-resistant resin of the present invention include methacrylic acid esters such as methyl methacrylate and methacrylic acid. ethyl,
Propyl methacrylate, cyclohexyl methacrylate and isobornyl methacrylate; acrylic acid esters,
Mention may be made of, for example, methyl acrylate, ethyl acrylate, propyl acrylate and butyl acrylate; aromatic vinyl compounds such as styrene and α-methylstyrene. Of these, methyl methacrylate, methyl acrylate, styrene, α-methylstyrene, and the like are preferably used because a resin having excellent reactivity and heat resistance can be obtained.

One of the low-coloring heat-resistant resins of the present invention is
It is a binary copolymer of the raw material and the copolymerizable monomer, and representative examples thereof include the raw material-methyl methacrylate copolymer, the raw material-cyclohexyl methacrylate copolymer, and the raw material- An isobornyl methacrylate copolymer etc. can be mentioned.

Polymerization of these binary copolymers is not particularly limited in the method, and can be carried out by a conventionally known method. For example, when the above raw material and methyl methacrylate are copolymerized, 5 to 50 parts by weight of the above raw material and 95 to 50 parts by weight of methyl methacrylate (total 100 parts by weight) are radically prepared by a conventional method using a radical polymerization initiator. It may be polymerized.

As another low-coloring heat-resistant resin of the present invention, at least one kind of monomer selected from the above-mentioned raw materials, methacrylic acid ester (particularly methyl methacrylate) and the above-mentioned copolymerizable monomer is used. Examples thereof include a terpolymer or a multi-component copolymer obtained by copolymerizing a monomer.

As typical examples thereof, the above raw material-methyl methacrylate-α-methylstyrene copolymer, the above raw material-
Examples thereof include a methyl methacrylate-styrene copolymer and the above raw material-methyl methacrylate-methyl acrylate copolymer.

The method of polymerizing these ternary or multi-component copolymers is not particularly limited in the same manner as the above-mentioned binary copolymer, and can be carried out according to a conventionally known method. For example, in the case of the above raw material-methyl methacrylate-styrene copolymer, 5 to 50 parts by weight of the above raw material and 95 to 50 parts by weight of methyl methacrylate, and a total of these 1
30 parts by weight or less of styrene with respect to 00 parts by weight may be radically polymerized by a conventional method using a radical polymerization initiator.

The radical polymerization initiator used in the production of the binary or multi-component copolymer is benzoyl peroxide,
Lauryl peroxide, tert-butyl peroxy-2-ethylhexanoate, persulfate, hydrogen peroxide,
Azobisisobutyronitrile or the like is used. The radical copolymerization reaction is usually performed at a temperature in the range of 40 to 150 ° C. for about 4 to 24 hours. The radical copolymerization reaction can be carried out by solution polymerization, suspension polymerization, bulk polymerization, emulsion polymerization or a combination thereof.

The N-cyclohexylmaleimide type heat-resistant resin of low coloration of the present invention is blended with various additives, for example, known additives such as ultraviolet absorbers and stabilizers, depending on the purpose of use. Then, it can be used as a thermoplastic resin composition. It can also be used by blending with other synthetic resins such as polymethylmethacrylate resin and methylmethacrylate-styrene resin.

[0032]

EXAMPLES The present invention will be specifically described below with reference to examples. In the following description, parts and% mean parts by weight and% by weight, respectively. The raw material for producing the heat-resistant resin of the present invention contains N-cyclohexylmaleimide as a main component, and cyclohexylaminosuccinic anhydride of 0.001
.About.1% (vs. N-cyclohexylmaleimide).

The structure of the cyclohexylaminosuccinic anhydride was identified and quantified by the following method.

Identification High Performance Liquid Chromatography (Shimadzu LC-10
The compound in N-cyclohexylmaleimide was fractionated using A), and the fractionated liquid was further vacuum dried at 30 ° C. The obtained solid content is chloroform: hexane = 1: 1.
It was recrystallized with the mixed solvent of and then dried. Then, the obtained solid content was analyzed by an infrared spectrophotometer (Nippon Biorat F
TS-7 / SPC-3200), superconducting Fourier transform nuclear magnetic resonance apparatus (Varian VXR-300S), gas chromatograph mass spectrometer (JEOL JMS-AX50).
5WA) and a melting point measuring device (501K, manufactured by Bich). The spectral and analytical values were as follows:

IR (KBr): ν (cm ^-1 ) = 3400
s, 2930s, 1695vs, 1390s, 1195
^{s, 1120s, 735m, 590m 1} H-NMR (300MHz, DMSO-d 6): δ
(Ppm) = 6.05 (1H, J = 6.0 Hz, d),
4.40 (1H, m), 3.80 (1H, m), 2.9
5 (1H, J = 18, J = 7.2, dd), 2.40
(1H, J = 18, J = 5, dd), 2.00 (2H,
J = 12.7, g), 1.80 (2H, J = 15,
d), 1.6 (3H, m), 1.20 (3H, m) ¹³ C-NMR (300 MHz, DMSO-d ⁶ ): δ
(Ppm) = 178.13 (1C), 174.8 (1
C), 65.8 (1C), 50.4 (1C), 37.6.
(1C), 28.6 (1C), 28.3 (1C), 2
5.4 (2C), 24.9 (1C) GC-MS = 197 ⁺ melting point = 155.5-156.5 ° C. quantitative high-performance liquid chromatography (Shimadzu LC-10
A) was used to prepare a calibration curve for cyclohexylaminosuccinic anhydride, and then the content of cyclohexylaminosuccinic anhydride in N-cyclohexylmaleimide was measured under the following conditions.

Column: Shimadzu Zorbax-ODS (4.
6 mmΦ × 25 cm) Mobile phase: 0.005 mol / liter mixed solution of potassium dihydrogen phosphate aqueous solution and methanol at 1: 0.818 (weight ratio) Column temperature: 45 ° C. Flow rate: 0.8 ml / min Detector : Hitachi, Ltd. 6.55A, UV220nm Sample preparation: Sample 0.4 in a 50 ml volumetric flask.
g was precisely weighed, dissolved and weighed in the mobile phase, and 20 μl was injected for analysis.

Reference Example 1 A flask equipped with a thermometer, a cooling tube equipped with a water separator, a dropping funnel, and a stirrer was charged with maleic anhydride and 5 parts by weight of ortho-xylene per unit weight of maleic anhydride. A uniform ortho-xylene solution of maleic anhydride was prepared by dissolving at 0 ° C. Then, to this maleic anhydride solution, a solution containing cyclohexylamine in an amount equivalent to that of maleic anhydride in a molar ratio and an equivalent weight of orthoxylene to the maleic anhydride solution was added dropwise over 0.5 hour under stirring at the same temperature, and N- A slurry of ortho-xylene of cyclohexylmaleamic acid was synthesized.

Next, in the above slurry solution, 20 parts by weight of orthophosphoric acid as an acid catalyst and cyclohexylamine and 20 parts by weight of N-cyclohexylmaleamic acid as a polymerization inhibitor are added.
0 ppm of copper dibutyldithiocarbamate was added, and the mixture was heated and kept at 140 ° C. under stirring, and the reaction was carried out for 7 hours while distilling out water produced by the reaction together with orthoxylene out of the reaction system. After completion of the reaction, the acid catalyst layer separated into the lower layer from the reaction solution was separated and removed at 140 ° C.

Subsequently, the reaction solution was heated to 60 ° C., water in an amount equal to that of the organic layer was added, and the mixture was stirred and washed with water for 30 minutes to separate the aqueous layer, and then the orthoxylene was removed from the organic layer under a reduced pressure of 10 mmHg. Under reduced pressure of 5 mmHg, internal temperature 130-15
By simple distillation at 0 ° C., a white raw material containing N-cyclohexylmaleimide as a main component was obtained.

The content of cyclohexylaminosuccinic anhydride in the raw material thus obtained was measured.
5%. The content of cyclohexylaminosuccinic anhydride in the raw materials containing N-cyclohexylmaleimide as a main component used in the following Examples and Comparative Examples according to the present invention was adjusted by changing the degree of purification by distillation and recrystallization. .

[Example 1] 20 parts of a raw material made of N-cyclohexylmaleimide containing 0.9% of cyclohexylaminosuccinic anhydride and 80 parts of methyl methacrylate were mixed and deaerated under a reduced pressure of 200 mmHg for 10 minutes. 0.4 part of lauryl peroxide as a polymerization initiator was dissolved in the monomer mixture, and the mixture was molded by the following cast polymerization.

Cast polymerized solution was blown with nitrogen gas to be sufficiently saturated, and the resulting solution was placed on a glass plate (240 × 180 × 5 mm) with a soft vinyl chloride tube (7 × 4 mm) so that the distance between both glass plates was 4 mm.
Gently inject it into the frame fixed so that it becomes 5 in the water bath.
After heating at 5 ° C. for 20 hours, a transparent polymer plate having a thickness of 3.0 mm was obtained.

The polymer plate obtained by the above-mentioned cast polymerization was measured with a color difference meter (Σ80 manufactured by Nippon Denshoku Industries Co., Ltd.) using a JI
The yellowness index (YI) measured by transmitted light in accordance with SK-7103 was 0.8. Further, the glass transition temperature was measured according to JIS-K-7121 using a thermal analyzer (DSC-8230 / TAS-100 manufactured by Rigaku), and was 137 ° C.

Example 2 20 parts of a raw material made of N-cyclohexylmaleimide containing 0.01% of cyclohexylaminosuccinic anhydride and 80 parts of methyl methacrylate were mixed and deaerated under reduced pressure of 200 mmHg for 10 minutes. 0.4 part of lauryl peroxide as a polymerization initiator was dissolved in the monomer mixture, and cast polymerization was performed under the same conditions as in Example 1 to obtain a transparent polymer plate having a thickness of 3.0 mm. When the yellowness index (YI) and the glass transition temperature of this polymer plate were measured in the same manner as in Example 1, they were 0.8 and 137 ° C., respectively.

From the results of Examples 1 and 2, the N-cyclohexylmaleimide-methylmethacrylate copolymer obtained by using the raw material consisting of N-cyclohexylmaleimide having a cyclohexylaminosuccinic anhydride content of 1% or less was transparent. Also, it can be seen that the yellowness index (YI) is 1 or less, the coloration is low, and the glass transition temperature is 120 ° C. or more, which is excellent in heat resistance.

Comparative Example 1 20 parts of a comparative raw material consisting of N-cyclohexylmaleimide containing 1.8% of cyclohexylaminosuccinic anhydride and 80 parts of methyl methacrylate were mixed and deaerated under reduced pressure of 200 mmHg for 10 minutes. 0.4 part of lauryl peroxide as a polymerization initiator was dissolved in the monomer mixture, and cast polymerization was performed under the same conditions as in Example 1 to obtain a transparent polymer plate having a thickness of 3.0 mm. When the yellowness index (YI) and the glass transition temperature of this polymer plate were measured in the same manner as in Example 1, they were 2.4 and 138 ° C., respectively.

Comparative Example 2 20 parts of a comparative raw material made of N-cyclohexylmaleimide containing 2.5% of cyclohexylaminosuccinic anhydride and 80 parts of methyl methacrylate were mixed and deaerated under reduced pressure of 200 mmHg for 10 minutes. 0.4 part of lauryl peroxide as a polymerization initiator was dissolved in the monomer mixture, and cast polymerization was performed under the same conditions as in Example 1 to obtain a transparent polymer plate having a thickness of 3.0 mm. When the yellowness index (YI) and the glass transition temperature of this polymer plate were measured in the same manner as in Example 1, they were 4.0 and 137 ° C., respectively.

From the results of Comparative Examples 1 and 2, the N-cyclohexylmaleimide-methylmethacrylate copolymer obtained using the comparative raw material consisting of N-cyclohexylmaleimide having a cyclohexylaminosuccinic anhydride content of more than 1% was transparent. It can be seen that although it is excellent and has excellent heat resistance, it is markedly colored (yellowing).

[Comparative Example 3] 10 under reduced pressure of 200 mmHg
For 100 parts of methyl methacrylate degassed for a minute,
0.4 part of lauryl peroxide was dissolved as a polymerization initiator and cast polymerization was carried out under the same conditions as in Example 1 to obtain a transparent polymer plate having a thickness of 3.0 mm. The yellowness index (YI) and the glass transition temperature of this polymer plate were measured in the same manner as in Example 1 and found to be 0.8 and 11, respectively.
4 ° C.

From the results of Comparative Example 3, the methyl methacrylate polymer obtained by polymerizing methyl methacrylate alone without using N-cyclohexylmaleimide is transparent and has a low coloration but a glass transition. Temperature is 1
It can be seen that the heat resistance is inferior at 14 ° C.

[Example 3] In a stainless steel polymerization tank having a stirrer with an internal capacity of 20 liters, each having three first dropping tanks, second dropping tanks, and third dropping tanks, 15.75 parts of methyl methacrylate was added. , 6.25 parts of a raw material composed of N-cyclohexylmaleimide containing 0.01% of cyclohexylaminosuccinic anhydride, 25 parts of toluene, and pentaerythrityl-tetrakis [3- (3,5-di-
tert-Butyl-4-hydroxyphenyl) propionate] 0.0025 parts.

On the other hand, 15.75 parts of methyl methacrylate,
A first mixed solution of 6 parts of styrene and 10 parts of toluene was charged into the first dropping tank, and nitrogen gas was bubbled in advance to remove dissolved oxygen from the first mixed solution tank. In addition, a second mixed solution of 6.25 parts of a raw material made of N-cyclohexylmaleimide containing 0.01% of cyclohexylaminosuccinic anhydride and 10 parts of toluene was charged in a second dropping tank, and nitrogen gas was bubbled in advance to dissolve oxygen. It was removed from the second mixed solution. Further, a third mixed solution of 0.108 parts of tert-butyl peroxyisopropyl carbonate and 5 parts of toluene was charged into the third dropping tank, and nitrogen gas was bubbled in advance to remove dissolved oxygen from the third mixed solution.

While stirring the solution in the polymerization tank at 300 rpm, nitrogen gas was bubbled through the solution for 10 minutes to remove dissolved oxygen from the solution by replacing the gas with nitrogen gas. The temperature of the solution was started to rise, and when it reached 110 ° C, tert as a polymerization initiator
-Butyl peroxyisopropyl carbonate 0.0
2 parts were added to the above solution.

Then, the first mixed solution, the second mixed solution, and the third mixed solution were added to the first dropping tank for 3.5 hours.
The solution was added dropwise from the second dropping tank and the third dropping tank to the above solution in the polymerization tank, and the polymerization reaction was carried out for 7 hours under reflux at a polymerization temperature of 110 ° C. Then, the above-mentioned stabilizer was further added to 0.
0475 parts was added to the solution in the polymerization tank.

The polymerization liquid containing the copolymer in the polymerization tank was
The mixture was supplied to a 30 mm twin-screw extruder equipped with a vent controlled to a cylinder temperature of 240 ° C., vacuum devolatilized from the vent port, and the strand that came out was pelletized to obtain a copolymer pellet (1) as a heat-resistant resin of the present invention. It was The yellowness (YIso) of the solution of the copolymerized pellet (1)
l. ) Was 0.8.

Further, this copolymer pellet (1) was molded using an injection molding machine controlled at a cylinder temperature of 250 to 260 ° C., a mold temperature of 100 ° C. and an injection pressure of 950 kg / cm ^2, and was transparent with a thickness of 3 mm. I got a molded product.

When the yellowness index (YI) and the glass transition temperature of this molded product were measured in the same manner as in Example 1, they were 1.6 and 136 ° C., respectively.

From the results of Example 3, the N-cyclohexylmaleimide-methylmethacrylate copolymer obtained by using the raw material consisting of N-cyclohexylmaleimide having a cyclohexylaminosuccinic anhydride content of 1% or less was a yellow product of a molded product. The degree (YI) is 1.6, which is a low coloring property,
Further, it can be seen that the glass transition temperature is 120 ° C. or higher, which is excellent in heat resistance.

Comparative Example 4 Instead of the raw material made of N-cyclohexylmaleimide containing 0.01% of cyclohexylaminosuccinic anhydride in Example 3, it was made of N-cyclohexylmaleimide containing 1.8% of cyclohexylaminosuccinic anhydride. A comparative copolymer pellet (1) was obtained in the same manner as in Example 3 except that the comparative raw materials were used.
Yellowness (Y) in the solution of this comparative copolymer pellet (1)
Isol. ) Was 4.1.

Further, this comparative copolymer pellet (1)
Was molded in the same manner as in Example 3 to obtain a transparent molded product having a thickness of 3 mm. When the yellowness index (YI) and the glass transition temperature of this molded product were measured in the same manner as in Example 1, they were 6.4 and 136 ° C., respectively.

From the results of Comparative Example 4, the N-cyclohexylmaleimide-methylmethacrylate copolymer obtained by using the comparative raw material consisting of N-cyclohexylmaleimide having a cyclohexylaminosuccinic anhydride content of more than 1% is transparent and heat resistant. Although it is excellent, it can be seen that it is markedly colored (yellowing).

[0062]

The raw material for producing the heat-resistant resin of the present invention is N
-Based on cyclohexylmaleimide, cyclohexylamino succinic anhydride content of 0.001-1% by weight
(To N-cyclohexylmaleimide). The heat resistant resin of the present invention is obtained by copolymerizing the above raw material and at least one monomer copolymerizable with the raw material.

Since the above heat-resistant resin contains an N-cyclohexylmaleimide unit as a heat resistance-imparting component, with respect to heat resistance, an N-cyclohexylmaleimide-based resin having a glass transition temperature of 120 ° C. or higher is obtained. It has excellent properties.

In addition, the above heat-resistant resin of the present invention is obtained by using a raw material composed of N-cyclohexylmaleimide having a cyclohexylaminosuccinic anhydride content of 0.001 to 1% by weight, and therefore has a low coloring property. With respect to the yellowness index (YI) of 2 or less, or the yellowness index (YI) in solution (YI).
sol. ) Is 3 or less, preferably 2 or less. Further, in order to obtain a resin having high heat resistance, specifically, a glass transition temperature of 120 ° C. or higher, the coloring of the obtained heat resistant resin is reduced even if the ratio of N-cyclohexylmaleimide units is increased. And can be made highly transparent.

Therefore, the above-mentioned raw material contains N-cyclohexylmaleimide as a main component, and the amount of cyclohexylaminosuccinic anhydride is in the range of 0.001 to 1% by weight (vs. N-cyclohexylmaleimide). It is possible to reduce the coloring of the heat-resistant resin obtained from the above.

The above heat-resistant resin is excellent in transparency and heat resistance due to the use of the above-mentioned raw materials, and has low coloring property. Therefore, it is used for automobile parts, electric equipment parts, nameplates, signboards,
It has the effect of being suitably used in many fields such as lighting covers, decorative articles, and sundries.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Kishino 1 992 Nishikioki, Kamahama, Aboshi-ku, Himeji City, Hyogo Prefecture Nihon Shokubai Co., Ltd.

Claims (3)

[Claims] 1. A main component of N-cyclohexylmaleimide having a cyclohexylaminosuccinic anhydride content of 0.00.
A raw material for producing a heat resistant resin, which is 1 to 1% by weight (vs. N-cyclohexylmaleimide). 2. A heat-resistant resin obtained by copolymerizing the raw material according to claim 1 and at least one monomer copolymerizable therewith. 3. The heat resistant resin according to claim 2, wherein the yellowness index (YI) is 2 or less, or the yellowness index (YIsol.) In the solution is 3 or less.