JPS61141715A - Heat-resistant copolymer resin, its production and optical element comprising the same - Google Patents

Abstract

PURPOSE:An acrylic copolymer resin being equivalent in properties to a polymethyl methacrylate resin and having excellent heat resistance and high productivity, obtained by copolymerizing methyl methacrylate with an N- arylmaleimide. CONSTITUTION:A copolymer comprising 99-70wt% methyl methacrylate and 1-30wt% N-arylmaleimide. It has an intrinsic viscosity as measured in chloroform at 25 deg.C of 0.3-1.0dl/g. The amount of methyl methacrylate remaining in the copolymer should be 1.0wt% or below, and the amount of remaining N-arylmaleimide should be 0.3wt% or below. As the N-arylmaleimide, at least one selected from the N-phenylmaleimides and N-substituted phenylmaleimides of the formula (wherein R1-R3 are each H or a 1-4C alkyl or a halogen) is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heat-resistant resin, a method for producing the same, and an optical element. More specifically, it is a copolymer of methyl methacrylate and N-aryl mireimide, which has excellent transparency and heat resistance.

This invention relates to a methacrylic copolymer resin, a method for producing the same, and an optical element made from the resin.

Conventional technologyMethacrylic resin, whose main component is methyl methacrylate, has excellent optical properties and weather resistance, and has excellent mechanical properties.
Because it has relatively well-balanced performance in terms of thermal properties and moldability, these properties can be used to make signboards, lighting covers, nameplates, automobile parts, electrical equipment parts, decorations, and miscellaneous goods. It is widely used in many fields, and further applications are being developed.

However, the heat deformation temperature of the - side is around 100℃, which is insufficient heat resistance, which limits its application in many fields, and there is a deep-rooted demand for improved heat resistance. .

Many proposals have already been made regarding methods for improving the heat resistance of methacrylic resins. For example, methods for copolymerizing methyl methacrylate and α-methylstyrene, and methods for copolymerizing methyl methacrylate, α-methylstyrene, and maleic anhydride have been made. Copolymerization method (Japanese Patent Publication No. 49-101
No. 56), a method for copolymerizing methyl methacrylate, α-methylstyrene, and maleimide, a method for copolymerizing methyl methacrylate in the presence of a crosslinked polymer using a polyfunctional monomer, and a method for copolymerizing methyl methacrylate and methacrylic acid. A method of copolymerizing methyl methacrylate, α-methylstyrene, and acrylonitrile has been proposed. However, although the above proposed method improves heat resistance to some extent, the polymerization rate is extremely low, resulting in extremely low productivity, mechanical properties,
At present, many problems remain in practical use, such as poor weather resistance and optical properties, markedly colored molded products, and poor molding processability due to the narrow molding area.

A method of copolymerizing methyl methacrylate and N-arylmaleimide (Japanese Patent Publication No. 43-9753) has also been proposed, but the resin obtained by this method has excellent mechanical properties and weather resistance inherent to methacrylic resins. Moreover, since the copolymerizability of the monomers is different, the amount of residual monomer is large, so that moldability is poor, the appearance is impaired, and only colored products are obtained. Moreover, depending on the polymerization method, the inherent transparency of the methacrylic resin is significantly impaired.

In the end, all of the previously proposed methods lack practicality,
Particularly in the case of optical applications, the current situation is that it has not yet been adopted.

Problems to be Solved by the Invention The purpose of the present invention is to provide a resin that not only has excellent optical properties, mechanical properties, weather resistance, and moldability comparable to polymethyl methacrylate resin, but also has superior heat resistance. An object of the present invention is to provide an acrylic copolymer resin having good properties and productivity, a method for producing the same, and an optical element made of the resin.

Means for Solving the Problems The heat-resistant copolymer resin according to the present invention contains 99-70% by weight of methyl methacrylate and 1% by weight of N-arylmaleimide.
~30% by weight copolymer with an intrinsic viscosity of 0.3 to 1.0 dt/g measured in chloroform at 25°C
and the amount of residual methyl methacrylate in the copolymer is 1
．． 0% by weight or less and the amount of residual N-arylmaleimide is 0
．． Chil methacrylate 99-70% by weight at 3% by weight or less
A monomer mixture consisting of 1 to 30% by weight of N-arylmaleimide and N-arylmaleimide is subjected to suspension polymerization in the presence of the following three components (4), (B) and (0), or two components (B) and (2). Line 5 is characterized by:

(4) (1) Acrylic acid alkyl ester and/or methacrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms (1) 0 to 60% by weight and lithium, sodium, and potassium acrylic acid and/or methacrylic acid and ammonium salts (IO100
A water-soluble polymer obtained by polymerizing ~40% by weight, (B) (a) an acrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms and/or a methacrylic acid alkyl ester (130 to 60% by weight) and(
b) at least one salt of acrylic acid and/or methacrylic acid selected from the group consisting of lithium, sodium, potassium and ammonium salts of acrylic acid and/or methacrylic acid (100 to 20% by weight and (c) general formula % formula % However, RIR'eR'=H or CH,, Hs x=-o-, -NH- or -N-1 M=H, Li, Nae K or NH4, n=
A water-soluble polymer obtained by polymerizing an acrylic acid conductor or a methacrylic acid conductor (IID 100 to 20% by weight) represented by an integer of 1 to 3, (electrolyte having a 0-valent cation).

In the heat-resistant copolymer resin of the present invention, in order to maintain the excellent mechanical properties and weather resistance of methacrylic resin,
It is necessary that the amount of methyl methacrylate units in the copolymer be in a predominant amount relative to the amount of N-arylmaleimide units. In addition, if we consider dissolving N-arylmaleimide in the monomer mixture and stabilizing the polymerization, a monomer consisting of 99 to 70% by weight of methyl methacrylate and 1 to 30% by weight of N-arylmaleimide may be used. It is necessary to copolymerize the polymer mixture. If the weight ratio of methyl methacrylate exceeds 99, the effect of improving heat resistance will be small. Note that it is also possible to copolymerize a small proportion of a monomer copolymerizable with methyl methacrylate and N-arylmaleimide, as long as the purpose of the present invention is not impaired.

The heat-resistant copolymer resin of the present invention needs to have an intrinsic viscosity Co measured in chloroform at 25°C in the range of 3 to 1 dt/g in order to obtain fluidity suitable for use as a molding material. , a range of 0.35 to 0.8 dt/l is preferred. In particular, in order to obtain an injection molded product with little distortion and good appearance for optical applications, it is desirable that the number is 0.35.

In order for the heat-resistant copolymer resin of the present invention to have an excellent appearance with little coloring, it is generally necessary that the residual monomer in the copolymer is 1.5% by weight or less, and preferably 1.5% by weight or less. .0% by weight or less. More specifically, the residual N-arylmaleimide is particularly likely to cause coloring, and should be kept at 0.3% by weight or less, preferably 0.2% by weight or less. Residual methyl methacrylate is the main cause of deterioration of appearance due to volatilization during heat processing such as silver and foaming], and must be kept at 1.0% by weight or less, preferably 0.9% by weight or less.

The N-arylmaleimide used in the present invention is N-
Phenylmaleimide and substituted rust conductors thereof,
The one represented by the following formula (2) is preferred, and R, , R2 and R3 may be the same or different and are selected from hydrogen, an alkyl group having 1 to 4 carbon atoms, and a halogeno group. It will be done. As the halodane substituted product, chloro and bromine substituted products are recommended from the viewpoint of easy availability.

Examples of such N-arylmaleimide monomers include N
-(2-chlorophenyl)maleimide, N-(2-bromphenyl)maleimide, N-(4-chlorophenyl)
Maleimide, N-(2゜4.6-)IJdichlororenyl)maleimir, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2-
Examples include t-butylphenyl)maleimide, N-(4-tethylphenyl)maleimide, N-(2,6-dimethylphenyl)maleimide, and N-(2-ethylphenyl)maleimide.

A copolymer consisting of methyl methacrylate and N-arylmaleimide can be produced, in principle, by bulk, solution emulsion or M-turbid polymerization, as described in Japanese Patent Publication No. 43-9753. However, in order to stably produce a resin with excellent optical properties comparable to polymethyl methacrylic 1-note resin, which is the object of the present invention, it is necessary to produce the resin by suspension polymerization. is desirable.

Bulk polymerization requires special reactors and devolatilizers, and reaction control is complicated. Solution polymerization has the same drawbacks as bulk polymerization and is inferior in productivity compared to bulk polymerization. The sheet polymerization method, in which a monomer mixture or a partially polymerized mixture is injected into opposing cells and polymerized, is also a type of bulk polymerization method, but it has low productivity and requires crushing and recycling in order to use it as a molding material. It is not adopted because it requires a process such as shaping.

Emulsion and suspension polymerization are more advantageous than the above methods in controlling equipment and polymerization conditions. However, emulsion polymerization requires a large amount of emulsifier to emulsify the monomer mixture, and as a result, the copolymer becomes wrinkled and has inferior transparency compared to suspension polymerization. In addition, there are problems with the stability of the polymerization system, and depending on the composition, [[] often solidifies during the reaction. Therefore, the heat-resistant copolymer resin of the present invention is preferably produced by suspension polymerization.

During polymerization, it is especially important on an industrial scale to stably disperse the reaction system and produce polymer beads with uniform particle diameters. It is equally important that the copolymer is not colored or contaminated by the compound used. In order to do so, the following (4), Q3) and (C) are required.
It is important to carry out the suspension polymerization in the presence of the three components (B) and (C).

(4) (&) 0 to 60% by weight of acrylic acid alkyl ester and/or methacrylic ester (1) having an alkyl group having 1 to 12 carbon atoms, and lithium, sodium, potassium and acrylic acid and/or methacrylic acid. A water-soluble polymer obtained by polymerizing 100 to 40% by weight of acrylic acid and/or methacrylic acid selected from the group consisting of ammonium salts, (B) (-) Alkyl having 1 to 12 carbon atoms; acrylic acid alkyl ester and/or methacrylic acid ester having groups (I) 0 to 60% by weight and (b) lithium, sodium, acrylic acid and/or methacrylic acid;
At least one salt of acrylic acid and/or methacrylic acid selected from the group consisting of potassium and ammonium salts (IDO~2o heavy tS and (c) general formula, where R+ 'F', R'=Ht or cH3, M=
H, Ll, Na, K or NH4, n = 1
A water-soluble polymer obtained by polymerizing an acrylic acid conductor or a methacrylic acid derivative (10100 to 20 t1) represented by an integer of ~3, (an electrolyte having a Q-valent cation).

Examples of the acrylic acid or methacrylic acid derivative (g) represented by the general formula (1), which is one component constituting the water-soluble polymer (B), include sodium salt of 2-sulfonityl methacrylate, methacrylic acid Examples include the sodium salt of 2-sulfonityl, the potassium salt of 2-acrylamido-2-methylproaminsulfonic acid, and the like.

An electrolyte having a monovalent cation (Q is, for example,
Lithium, sodium, potassium and ammonium salts of inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid; lithium, sodium, potassium and ammonium salts of lower carbenoic acids having 1 to 4 carbon atoms; and aliphatic and aromatic sulfonic acids. Examples include lithium, sodium, potassium and ammonium salts.

The proportions of the above compounds (B) and (9) are 0 to 1 part by weight (A) and 1 part by weight (B) to 100 parts by weight of the monomer to be suspension polymerized.
) 0.002 to 1.0 parts by weight, (C) 0.05 to 10
Parts by weight are preferred. Although the stability of the reaction system can be maintained even if (4) is not used in combination, it is preferable to use it in combination to reduce the amount of polymer adhering to the wall and giant particles and to make the particle size uniform. A more preferable ratio of (B) is 0.003 parts to 1,01 parts by weight; if it is less than 0.001 parts by weight, the dispersion effect will be insufficient, and even if the amount exceeds 1 part by weight, suspension polymerization will not occur. can be carried out smoothly, but the diversification effect does not increase much and it is not economically advisable to do so.
A more preferable ratio is in the range of 0.1 to 5 parts by weight; if the amount of electrolyte added is too small, the amount of undesirable amorphous powder/IJ mother particles will increase in addition to normal spherical particles. On the other hand, if it is too large, the particle size tends to be too large, which will eventually lead to solidification.

Among other known suspension methods, for example, in a method in which polymerization is carried out using an alkaline dispersion system in which the - of the reaction system exceeds 8, the dispersion system becomes unstable as the reaction progresses, and it tends to solidify and cannot be used. Systems using CMC (caloxymethylcellulose) have poor dispersibility, and even when Popal is used, they tend to solidify, and the copolymer remains cloudy, resulting in optically inferior products.

Polymerization using a sparingly soluble inorganic salt (for example, calcium hydrogen phosphate, tertiary calcium phosphate, etc.) and an anionic surfactant as a dispersant is also a promising suspension polymerization method, but the stability of the dispersion system is Depending on the composition, it may be bad.
Furthermore, since it is necessary to perform acid washing, copolymers have the disadvantage that it is difficult to avoid staining and coloring caused by dispersants.

(A), (B) and (C) in the method of the present invention
Suspension polymerization using a dispersant consisting of the three components (B) and (C) or two components (B) and (C) may be carried out according to a conventional method.

For example, in one reactor, water, monomers, a dispersant consisting of components ω) and (C), a polymerization initiator, a chain transfer agent, and if desired, auxiliary agents such as dyes and pigments are dissolved (mixed) and monomers are charged. ,
Polymerize in a dispersed state while stirring. The monomer and polymerization initiator may be charged in their entirety into the reactor before polymerization, or a portion may be added at the beginning and the monomer or polymerization initiator may be added continuously or intermittently as the polymerization progresses. Good too.

Furthermore, when producing the resin of the present invention, a chain transfer agent such as mercaptan can be used for the purpose of controlling the molecular weight. Examples of mercaptans used are primary, secondary, tertiary mercaptans with alkyl or substituted alkyl groups; for example n-butylmercaptan, inbutylmercaptan, n-octylmercaptan, n-dodecylmercaptan. , S@a-butylmercaptan, sea-dodecylmercaptan, tsrt, -butylmercaptan, tart, -dodecylmercaptan;
Aromatic mercaptans, e.g. phenylmercaptan,
Examples include mercaptans having 3 to 180 carbon atoms, such as thiocresol, 4-tart, -butyl-0-thiocresol; thioglycolic acid and its ester; and ethylene glycol. These can be used alone or in combination of two or more. Among these mercaptans,
Preference is given to tert,-butylmercaptan, n-butylmercaptan, n-octylmercaptan, n-dodecylmercaptan and t@rt,-dodecylmercaptan. When using mercaptan, the amount used is 1
The molar ratio is less than 1 molar relative to ft', 4. 1 mole eII
If it exceeds t, the molecular weight is small and the physical properties are deteriorated.

As the polymerization initiator added to the monomer, known oil-soluble ones can be used, such as acetyl peroxide, glopionyl peroxide, butyryl peroxide, cagrilyl peroxide,
Diacyl groups such as octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, stearoyl peroxide, benzoyl peroxide, and 2,4-dichlorohensoyl peroxide; t-butyl/4'-acetate, t- Butyl perpivalate, t-butylno J? -Octanoate, t-
Ester such as butyl/4-benzoate; 2.2
Examples include azobis compounds such as '-7zobisinbuteronitrile and 2,2'-azobis-2,4-dimethylvaleronitrile.

The polymerization temperature during suspension polymerization varies depending on the type and amount of the polymerization initiator used, the type of monomer, etc., but in the case of the present invention, it is within the range of 50 to 150°C.

Furthermore, the weight ratio of the oil phase to the aqueous phase during suspension polymerization is within the range of oil phase/aqueous phase = 1/10 to 1/1, preferably 1/1.2 to 1/3. Within range.

The polymer beads obtained by the production method of the present invention are devolatilized and extruded by a known method, shaped, and made into pellets.

It can be made into a flat shape. In this case, it is particularly important to keep the residual N-arylmaleimide in the polymer beads at 1 weight or less in order to suppress coloring of the resin. This residual monomer removal is carried out at 100 parts by weight per 100 parts by weight of polymer beads.
This is accomplished by washing with at least parts by weight of a solvent that does not dissolve the polymer beads. If the solvent is less than 100 parts by weight, the cleaning effect will be small, and if it exceeds 1000 parts by weight, cleaning is possible, but the cleaning effect will not be improved and it is economically disadvantageous. The cleaning temperature used is in the range of room temperature to 100°C, particularly preferably in the range of 35 to 70°C. Examples of the solvent include methanol, ethanol, hexane, etc. In particular, it is preferable to use methanol.

In the resin of the present invention, depending on the product type and quality requirements, small amounts of other comonomers may be used in combination, plasticizers,
A crosslinking agent, a heat stabilizer, a coloring agent, an ultraviolet absorber, a building release agent, etc. can also be added.

EXAMPLES Hereinafter, the present invention will be further explained in detail with reference to examples. In the examples, parts indicate parts by weight, and 忤 indicates weight %, respectively. In addition, both the dispersant and ω) were synthesized as follows.

Synthesis example of the dispersant component (A-1) Methyl methacrylate 30I, methacrylic acid strength I77011, deionized water 400JiF in internal volume 2
7 while stirring under a nitrogen atmosphere in a 000- flask.
The temperature was raised to 0°C, 0.111% of ammonium persulfate dissolved in 10 ml of deionized water was added, and the temperature was raised to 80°C. 6
Add 490 liters of water for an hour to dilute and cool/+7
A cloudy solution with a concentration of about 1 (1) and a viscosity of about 370 ep (25° C.) was obtained.

(A-2) A cloudy white bath liquid with a viscosity of about 260 ap was obtained in the same manner as in (A-1) except that 35 g of ethyl acrylate and 651 g of ammonium methacrylate were used.

(A-3) A cloudy white solution with a viscosity of about 190 ep was obtained in the same manner as in (A-1) except that butyl acrylate 25II and potassium methacrylate 7511 were used.

Synthesis example (B-1) of dispersing agent component (B-1) 100 J' of sodium salt of 2-sulfonityl methacrylate and 9001 J of deionized water were mixed into an internal volume of 20
5 with stirring under nitrogen atmosphere in a flask of 0Qx/
Raise the temperature to 0℃, add 0.1# of ammonium persulfate, and
The temperature was raised to 0°C. After 6 hours of cooling, the viscosity is approximately 840 op.
A clear solution was obtained with .

(B-2) Sodium salt of 2-sulfonityl methacrylate 8011. A slightly cloudy solution with a viscosity of about 670 ep was obtained in the same manner as in (B-1) except that methyl methacrylate 201 was used. (B-3) Sodium salt of 2-sulfonyl methacrylate 6011 Potassium methacrylate 101. The viscosity was approximately 800 ap in the same manner as in (B-1) except that ethyl methacrylate 30I was used.
A cloudy solution was obtained.

The evaluation of the properties in the Examples was carried out in accordance with the following standards.

VSr (Pikar) Softening degree) ABTM D1
525HDT (Heat Distortion Temperature) ASTM
0648 Total light transmittance ASTM D1
003 Parallel light full transmittance A8TM D1003 Haze value
ASTM D1003 MFR (flowability, 230℃, load 10kIP) ABT
M D1238 tensile strength ABT
M D638 Tensile Elongation ASTM
D638 Izot impact strength ABTM
D-256 Example 1 Dispersant components of 270ON (D deionized water, B-1,0,541 and sulfuric acid) + 7um 9I were charged in a flask with an internal volume of 5000, and methyl methacrylate 80
parts, 20 parts of N-(2-chlorophenyl)maleimide, n
- 1800.9 parts of a monomer solution consisting of 0.23 parts of octyl mercaptan and 0.1 parts of azopisintuthyronitrile
and heated to 35 Orpm with substantially no oxygen.
Suspension polymerization was carried out by heating at 80° C. for 2 hours while stirring.

The polymerization system remains stable until the end of polymerization, and adheres to large particles, flask walls, and stirring blades/IJ polymers or floats on the top of the water surface/IJ Marbees is rarely observed and has an average diameter of 0. Polymer beads with a uniform particle size of 29 mm were obtained. In the polymer beads after dehydration and drying,
Methyl methacrylate 1.4es as residual mono i-,
and N-(2-chlorophenyl)maleimide 1.11 were measured by gas chromatography in a conventional manner.

500 parts of methanol was added to 100 parts of the polymer beads, stirred, heated at 40°C for 1 hour, filtered, and dried. No particular secondary aggregation was observed. The residual monomer amount was 0.2# or less in all cases. The polymer beads were extruded at 250° C. using a twin-screw extruder with a two-vent shed, shaped, and used for physical property evaluation. The intrinsic viscosity of this pellet measured in chloroform at 25°C is 0.53 dl.
/i and pressure molded product o vsp and HDT are each 13
The temperatures were 7°C and 120°C. Fluidity MF″R is 3.5g/
It was molded at 250° C. for 10 minutes, and the optical properties and mechanical properties were measured, and the following values were obtained.

Total light transmittance 91.0chi Haze value 1.1chi Plate thickness 2m Tensile strength 548yu/cry? Tensile elongation
1.6cs Izotsu bond 1 steepness 1.2kecm/c
m (mild notch) It is clear that the physical properties as a diacrylic molding material are maintained and the heat resistance is significantly improved. In addition, the water absorption rate was lower than that of the acrylic molding material Acrybella VH (manufactured by Mitsubishi Rayon ■), and there was less deformation due to water absorption, so it could be advantageously used as an optical element.

Using this pellet, a lens with a center thickness of 311,111 mm was molded. Refractive index = 1.517, dispersion D = 47.8
It is solid and transparent, shows no coloration, has almost no optical distortion, has good mold reversibility, and can be used satisfactorily even at 100°C.

Example 2 and Comparative Examples 1 to 4 Using the same equipment as in Example 1, the dispersant components shown in Table 1 were charged, and the monomer phase contained 80 parts of methyl methacrylate, 20 parts of N-7-enylmaleimide, and n-octyl. Mercadeta yO, 22 parts, azobisin butyronitrile 0.1
Table 1: Suspension polymerization was carried out in the same manner as in Example 1 except that
The results were obtained. The industrial production advantages of the process according to the invention are clear.

The polymers of Margin Example 2 and Comparative Example 4 were evaluated in the same manner as in Example 1, and the results shown in Table 2 were obtained.

Table-2 MFR (1710 minutes) 5.6 6.0
Intrinsic viscosity (dt/, 9) 0.57 0
．． 57VSP(C) 138
136HDT(6) 120
120 tensile strength (k17/I:rR”)
521 494 Tensile elongation (%)
1.5 1.4 Also, using this pellet 2
A specimen measuring 110 m (t) x 110 m was injection molded, and its grindability was evaluated using a Takume Seiki 1HD-30W handrail machine. No polymer adhesion was observed, good grindability was obtained, and lens processing was also possible by grinding.

Incidentally, polymer deposits were observed on the acrylic resin (Acriped VH manufactured by Mitsubishi Rayon ■) used for comparison.

In addition, at the time of extrusion shaping in Examples 1 to 2 and Comparative Examples 1 to 4, 0.1 part of stearic acid monoglyceride was blended as a mold release agent with respect to 100 parts of poly-1 beads.

Examples 3 to 5 and Comparative Example 5 Using a pressure-resistant polymerization pot with an internal volume of 50 tons, 30 kli of deionized water and various dispersion components shown in Table 3 were charged, and
The monomer phase composition was also prepared in the ratio shown in Table 2, and 15 liters of nitrogen was added to it, and while stirring at 180 rpm, 10 liters of nitrogen was added.
→ After bubbling for 20 minutes at a flow rate of 200℃, heating at 80℃ for 2 hours to cause suspension polymerization, and further raising the temperature to 105℃,
It was held for 5 minutes, post-treated, cooled and dried. The obtained polymy pieces were washed with methanol in the same manner as in Example 1, filtered and dried, and then extruded and shaped in the same manner as in Example 1 to obtain pellets. In Comparative Example 5, the post-polymerization heat treatment and methanol washing were omitted, and the rest of the process was exactly the same as in Example 5 to obtain pellets.

The results of evaluating the physical properties of the obtained polymer are shown in Table 4. Comparing with Example 5, Comparative Example 5 was significantly inferior in heat resistance, mechanical properties, and optical properties.

2W of Example 3 was subjected to an accelerated exposure test for 1000 hours using an injection molded specimen using a Suga weather tester under the conditions of a temperature of 60°C, Kagen arc lamp, and 12 minutes of rain per hour. However, there is almost no change in the appearance and it has excellent weather resistance.9.

An injection molded specimen of Example 3 3 was placed in pure water at 100°C.
As a result of immersion for a period of time and visual judgment of the degree of whitening, no particular change was observed, and the boiling resistance was also good.

From the above, it can be confirmed that the resin composition of the present invention sufficiently retains the characteristics as an acrylic resin.

Effects of the Invention The resin of the present invention maintains excellent optical properties, mechanical properties, weather resistance, and moldability almost comparable to polymethyl methacrylate, and has excellent heat resistance and productivity.

Since the resin of the present invention has the above-mentioned properties, it is useful for the following uses.

It can be used in fields where acrylic resin is used, such as signboards, lighting covers, nameplates, automobile parts, electrical equipment parts, decorations, and miscellaneous goods.

It can be used in fields that require particularly high heat resistance.

Also, in the field of optical elements, especially for lenses,
It has a high refractive index, high heat resistance, low moisture absorption, and has excellent surface properties and processability necessary for lenses, so it is stable in form and can be used widely and advantageously even in environments other than acrylic resin. (Examples include pickup lenses, lenses for glasses, lenses for cameras, Fresnel lenses for projectors, etc.)

In addition, substrates for optical disks and cores of optically transmitting fibers are also used.
i is also used as a sheath material.

Claims (1)

[Claims] 1. 99 to 70% by weight of methyl methacrylate and N-
A copolymer consisting of 1 to 30% by weight of arylmaleimide, with an intrinsic viscosity of 0 when measured in chloroform at 25°C.
．． 3 to 1.0 dl/g, and the amount of residual methyl methacrylate in the copolymer is 1.0% by weight or less and the amount of residual N-arylmaleimide is 0.3% by weight or less. Polymer resin. 2 N-arylmaleimide is represented by the following formula (2)
The heat-resistant copolymer resin according to claim 1, which is at least one selected from the group consisting of -phenylmaleimide and N-substituted phenylmaleimide. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (2) In the formula, R_1, R_2, and R_3 represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a halogen. 3 A monomer mixture consisting of 90 to 70% by weight of methyl methacrylate and 1 to 30% by weight of N-arylmaleimide is combined with the following three components (A), (B) and (C), or (B) and (C). Suspension polymerization was carried out in the presence of two components, and the intrinsic viscosity measured in chloroform at 25°C was 0.3 to
1.0 dl/g, the amount of residual methyl methacrylate in the copolymer is 1.0% by weight or less, and the amount of residual N-arylmaleimide is 0.3% by weight or less. Method for producing heat-resistant copolymer resin. (A) (a) 0 to 60% by weight of an acrylic acid alkyl ester and/or methacrylic acid alkyl ester (I) having an alkyl group having 1 to 12 carbon atoms, and lithium and sodium acrylic acid and/or methacrylic acid;
Salt of acrylic acid and/or methacrylic acid selected from the group consisting of potassium and ammonium salts (II) 10
Water-soluble polymer obtained by polymerizing 0 to 40% by weight, (B) (a) Acrylic acid alkyl ester and/or methacrylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms (I) 0 to 60 (b) at least one salt of acrylic acid and/or methacrylic acid selected from the group consisting of lithium, sodium, potassium and ammonium salts of acrylic acid and/or methacrylic acid (II) 0 to 20% by weight; and (c) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(1) However, R, R', R″=H or CH_3, X=-O
-, -NH- or ▲Mathematical formulas, chemical formulas, tables, etc.▼
, M=H, Li, Na, K or NH_4, a water-soluble polymer obtained by polymerizing 100 to 20% by weight of an acrylic acid derivative or methacrylic acid derivative (III) represented by an integer of n=1 to 3. , (C) an electrolyte having a monovalent cation. 4. The method for producing a heat-resistant copolymer resin according to claim 3, wherein 100 parts by weight of polymer beads obtained by suspension polymerization are washed with 100 parts by weight or more of a polymer-insoluble solvent. 5 99-70% by weight of methyl methacrylate and N-
A copolymer consisting of 1 to 30% by weight of arylmaleimide, which has an intrinsic viscosity of 0 when measured in chloroform at 25°C.
．． 3 to 1.0 dl/g, and the amount of residual methyl methacrylate in the copolymer is 1.0% by weight or less and the amount of residual N-arylmaleimide is 0.3% by weight or less. An optical element characterized by: 6 N-arylmaleimide is represented by the following formula (2)
The optical element according to claim 5, which is at least one selected from the group consisting of -phenylmaleimide and N-substituted phenylmaleimide. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (2) In the formula, R_1, R_2, and R_3 represent hydrogen, an alkyl group having 1 to 4 carbon atoms, or a halogen.