JPH061903A - Polymer composition - Google Patents

Abstract

PURPOSE:To obtain a compound having excellent transparency, heat resistance, a high cloud point and characteristics of both the components by blending a specific methyl methacrylate copolymer with a polycarbonate. CONSTITUTION:(A) 75-95 pts.wt. copolymer comprising 35-98wt.%, preferably 40-95wt.% methyl methacrylate unit, 1-30wt.%, preferably 5-25wt.% methacrylic acid ester unit of formula I (R is benzyl or methylbenzyl), 1-25wt.%, preferably 5-20wt.% maleimide unit of formula II (X is cyclohexyl or methylcyclohexyl) and 0-10wt.% another copolymerizable vinyl monomer is blended with (B) 5-25 pts.wt. aromatic polycarbonate resin. Benzyl methacrylate is preferable as the unit of formula I. Cyclohexylmaleimide is preferable as the unit of formula II. The component A has an average molecular weight of preferably 0.3-1.1dl/g, especially 0.35-1.0dl/g intrinsic viscosity in solution in chloroform at 20 deg.C in terms of strength characteristics and melting properties.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polymer composition,
In particular, it relates to a polymer composition comprising a methyl methacrylate copolymer and an aromatic polycarbonate.

The polymer composition obtained by the present invention has excellent transparency and is a molding material having both properties of polymethylmethacrylate and aromatic polycarbonate.
Also used as films, sheets, and various molded products,
Particularly, it is preferably used as an optical molded product such as a lens and an optical disk substrate.

[0003]

2. Description of the Related Art Polymethylmethacrylate has excellent properties such as transparency, weather resistance and surface hardness. But,
This resin has problems such as insufficient heat resistance and mechanical properties and high water absorption depending on the application, and improvement of these problems is required. On the other hand, aromatic polycarbonate,
In particular, polycarbonate produced from bisphenol A has excellent mechanical properties, heat resistance and transparency, but has problems such as large residual strain and large orientation birefringence due to poor fluidity during molding. Have. Therefore, in order to obtain a resin having excellent characteristics of both polymethylmethacrylate and aromatic polycarbonate, it is conceivable to mix both resins. However, when a film is formed by mixing polymethyl methacrylate and bisphenol A in tetrahydrofuran, which is a common solvent, a transparent complete compatibilized product is obtained, but a cloud point of a mixture of these two resins is about 180. Since it is ℃, it separates into two phases at high temperature. Therefore, it is known that a complete compatible product cannot be obtained by the compatible kneading of poly (methyl methacrylate) and the aromatic polycarbonate, and the blended product exhibits a pearly luster and becomes opaque. (J. Pol
m. Sci. , Polm. phys. Ed. , 25, 1
459 [1987]. In order to improve the compatibility at high temperature, blending of a methyl methacrylate copolymer having various copolymer units and an aromatic polycarbonate has been attempted. For example, according to Japanese Patent Laid-Open No. 63-90551, a copolymer of methyl methacrylate and methacrylic acid amide, for example, methyl methacrylate and N-cyclohexyl amide, is a transparent blend obtained by melt-kneading bisphenol A with a polycarbonate. It is described to give. In addition, JP-A-63-
According to No. 256647, a copolymer of methyl methacrylate and maleimide, for example, a copolymer of methyl methacrylate and N-cyclohexylmaleimide, and a polycarbonate of bisphenol A is melt-kneaded to give a transparent or slightly cloudy blend. Is listed. However, the methyl methacrylate copolymers described in these publications have problems such as strong coloring and a low cloud point of the blend.

According to Japanese Patent Laid-Open No. 64-1749, in order to solve the above-mentioned problems, as a comonomer unit of a methyl methacrylate copolymer, a methacrylic acid ester unit having a carbocyclic group in the ester group and It is proposed to use a styrene unit and / or an α-methylstyrene unit in combination with an acrylate unit and / or an acrylate unit. According to JP-A-64-1745, a methyl methacrylate copolymer containing these comonomer units and a polycarbonate of bisphenol A give a transparent blend by kneading and extrusion, and the cloud point of the blend is It is higher than that of a blend of methyl methacrylate and a polycarbonate of bisphenol A. For example, in the case of a copolymer of methyl methacrylate and phenyl methacrylate, it is described that the cloud point of the blend is 250 ° C. or higher. ing.

It has been reported that it is possible to improve the compatibility with an aromatic polycarbonate by copolymerizing and modifying poly (methyl methacrylate) as described above. It cannot be said that the cloud point with the group polycarbonate is at a sufficiently high level. That is, when compared with polymethylmethacrylate, the blend has an increase in melt viscosity due to blending with polycarbonate, and therefore the molding temperature moves to a high temperature side. And those having a sufficiently high cloud point are not yet known. At present, the blend having the highest cloud point is a blend consisting of the above-mentioned methyl methacrylate copolymer containing phenyl phenyl methacrylate and an aromatic polycarbonate, but according to the study by the present inventors, this blend The cloud point of the product is about 250 ° C. at most, which is insufficient for properly selecting the molding conditions. Further, in the blend, the physical properties of the blend obtained together with the compatibility between the resin used and the resin have extremely important meanings. The blend using the copolymer prepared from methyl methacrylate and phenyl methacrylate in Example 48 of JP-A-64-1749 has a low glass transition temperature of 117 ° C. It has been reported that the introduction of other comonomer units into poly (methyl methacrylate) in this way can improve the compatibility with aromatic polycarbonates, especially at high temperatures, but so far it has not been possible to cause coloration during blending. At the present time, however, a blend of polymethylmethacrylate and aromatic polycarbonate having excellent transparency and heat resistance has not yet been obtained.

[0006]

Therefore, an object of the present invention is to provide a methyl methacrylate copolymer and an aromatic polycarbonate which have a cloud point higher than the molding temperature and are excellent in both transparency and heat resistance. Another object of the present invention is to provide a polymer composition.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention have conducted earnest studies on the copolymerization component of a methyl methacrylate copolymer, and as a result, have found that methyl methacrylate and methacrylic acid having a benzyl group. The inventors have found that a blend of an aromatic polycarbonate and a copolymer of an ester and cyclohexylmaleimide has a high cloud point, is excellent in transparency and heat resistance, and has completed the present invention.

That is, the gist of the present invention is that the methyl methacrylate unit is 35 to 98% by weight and the following general formula (1)

[0009]

[Chemical 3] (In the formula, R is a benzyl group or a methylbenzyl group) Methacrylic acid ester unit 1 to 30% by weight,
The following general formula (2)

[0010]

[Chemical 4] (In the formula, X represents a cyclohexyl group or a methylcyclohexyl group), 1 to 25% by weight of a maleimide unit, and 0 to 10 other copolymerizable vinyl monomer units.
It is achieved by a polymer composition comprising 75 to 95 parts by weight of a copolymer (A) composed of 5% by weight and 5 to 25 parts by weight of an aromatic polycarbonate resin (B).

The present invention will be described in detail below. The copolymer (A) of the present invention comprises a methyl methacrylate unit and the following general formula (1).

[0012]

[Chemical 5] (In the formula, R is a benzyl group or a 4-methylbenzyl group), and a methacrylic acid ester unit represented by the following general formula (2)

[0013]

[Chemical 6] (In the formula, X represents a cyclohexyl group or a methylcyclohexyl group) and a maleimide unit represented by the formula, and another copolymerizable vinyl monomer position are contained as essential components.

Examples of the monomer represented by the above general formula (1) include benzyl methacrylate and 4-methylbenzyl methacrylate, and benzyl methacrylate is particularly preferable.

Examples of the monomer represented by the above general formula (2) include cyclohexylmaleimide and methylcyclohexylmaleimide, and cyclohexylmaleimide is particularly preferable.

The content of the methyl methacrylate unit in the copolymer (A) of the present invention is 3 in order to maintain good weather resistance and transparency which are characteristics of polymethyl methacrylate.
It is 5 to 98% by weight, preferably 40 to 95% by weight.

The content of the monomer unit represented by the general formula (1) in the copolymer (A) of the present invention is 1 to 30% by weight, preferably 5 to 25% by weight. 1% by weight
If it is less than 1, the compatibility with the polycarbonate is lowered, which is not preferable. On the other hand, if the content exceeds 30% by weight, the compatibility with the polycarbonate is drastically lowered and the glass transition point of the copolymer is lowered, which is not preferable because the practical use is lost.

The content of the monomer unit represented by the general formula (2) in the copolymer (A) of the present invention is 1 to 25% by weight.
And preferably 5 to 20% by weight. If it is less than 1% by weight, there is a problem that the compatibility with the polycarbonate is lowered or the heat resistance of the copolymer cannot be maintained, and if it exceeds 25% by weight, the compatibility with the polycarbonate is low and it is transparent. However, there are problems such as not being able to obtain good properties and having low weather resistance.

In the copolymer (A) of the present invention, the content of the other copolymerizable monomer optionally used is within the range not impairing the effects of the present invention. ) Can be used if necessary for improving the fluidity, and the content is 0 to 10% by weight. If it exceeds 10% by weight, the glass transition point of the copolymer becomes low, and the practicality is lowered, or the compatibility with the polycarbonate is lowered.

Other copolymerizable vinyl monomers include, for example, acrylic acid esters such as methyl acrylate, ethyl acrylate and butyl acrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, Methacrylic acid esters other than methyl methacrylate and benzyl methacrylate, such as cyclodecyl methacrylate, are monomers such as styrene, vinyltoluene, acrylonitrile, methacrylonitrile, and the like.

The average molecular weight of the copolymer (A) of the present invention is not particularly limited, but from the viewpoint of strength characteristics and meltability, the intrinsic viscosity in a chloroform solution at 20 ° C. is preferably 0.3 to.
1.1 dl / g, more preferably 0.35-1.0 dl /
Those having a range of g are used.

The method for polymerizing the copolymer (A) of the present invention may be any of the generally known polymerization methods such as suspension polymerization method, solution polymerization method, bulk polymerization method and emulsion polymerization method. Examples of the polymerization initiator used in these polymerizations include azo compounds such as azobisisobutyronitrile and azobis (γ-dimethylvaleronitrile), or lauroyl peroxide, tert. Examples include organic peroxides such as -butylperoxy 2-ethylhexanoate and 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate.

Further, as a chain transfer agent used for controlling the molecular weight of the copolymer (A), n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-butyl mercaptan, t-dodecyl mercaptan, etc. Is.

Examples of the aromatic polycarbonate (B) used in the present invention include bisphenol A polycarbonate and 4,4-dihydroxydiphenylalkane polycarbonate, and bisphenol A polycarbonate is particularly preferable.

The polymer composition of the present invention is a copolymer (A).
Is 75 to 95 parts by weight and aromatic polycarbonate (B) 5
It is obtained by mixing ~ 25 parts by weight. When the proportion of the copolymer (A) is less than 75 parts by weight, transparency is lost, which is not preferable. Further, if the proportion of the copolymer (A) is less than 5 parts by weight, there is almost no effect of improving the strength, which is not preferable.

The method of mixing the copolymer (A) and the aromatic polycarbonate (B) is not particularly limited, and a conventional method can be used. For example, after mixing with a Brabender type mixer, a Henschel type mixer, etc. A molded product can be obtained by injection molding or compression molding after pelletizing using an extruder, or may be formed into a sheet by using an extruder.

In carrying out the present invention, additives such as an ultraviolet absorber, a heat stabilizer, an antioxidant, a lubricant, a release agent and a face wash can be added, if necessary, and polymerization, mixing and melting can be carried out. Any mixing step may be used.

[0028]

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The evaluation methods in the examples are as follows (1) to
It carried out by the method of (4).

(1) Total Light Transmittance and Haze After injection molding an N70A injection molding machine (Japan Steel Works) into an injection molded product of 50 length × 50 width × 3.2 thickness (mm), AS
It was measured according to the method of TM D1003.

(2) Glass transition point (Tg) DSC (SHIMAZU DSC-50) in nitrogen stream, heating rate 1
0 ° C./min. It was measured at.

(3) Intrinsic viscosity of copolymer (A) (dl /
g) A resin having a constant concentration was dissolved in chloroform using an automatic viscometer, and then measured at 20 ° C.

(4) Cloud Point (° C.) A THF solution in which the blended product was dissolved was spread on a cover glass using a glass rod to form a solvent film, which was then heated at 120 ° C.
After vacuum drying for 24 hours or more, the obtained thin film transparent blend was allowed to stand at each temperature for 15 minutes or more.

Synthesis Example 1 100 parts by weight of a monomer mixture of 80% by weight of methyl methacrylate, 10% by weight of benzyl methacrylate, and 10% by weight of cyclohexylmaleimide was added to 1,1,3,3-.
15 kg of a mixture of 0.15 parts by weight of tetramethylbutylperoxy 2-ethylhexanoate, 0.2 parts by weight of n-octyl mercaptan, and Exel T-95 (manufactured by Kao Corporation) and 0.5 parts of potassium polymethacrylate. Pure water in which 400 g of a weight% aqueous solution, 7 g of sodium dihydrogen phosphate and 22 g of disodium hydrogen phosphate were previously dissolved
g was charged into a 50 liter pressure resistant reactor equipped with a stirrer. Then, the inside of the tank was sufficiently replaced with nitrogen, and then polymerization was carried out at 80 ° C. After the exothermic peak, polymerization was further carried out at 120 ° C. for 1 hour.
After cooling this, washing, dehydration, and drying steps were performed to obtain a bead-shaped copolymer. The intrinsic viscosity of this copolymer (A) was 0.52 dl / g. This copolymer is 40φ (m
m) Pelletization was performed using an extruder (manufactured by Nakatani Kikai) to obtain colorless and transparent pellets.

Synthetic Examples 2 to 5 Polymerization was carried out under the same conditions as in Synthetic Example 1 except that the ratio of the monomer mixture shown in Table 1 was changed to the ratio shown in Table 1, and the same steps were carried out. After that, pellets having different compositions were obtained.

[0035]

[Table 1] The abbreviations in the table are as follows. CHMI: Cyclohexylmaleimide MCHMI: Methylcyclohexylmaleimide MA: Methyl acrylate EA: Ethyl acrylate Example 1 88 parts by weight of the copolymer (A) obtained in Synthesis Example 1 and an aromatic polycarbonate (Panlite AD550 manufactured by Teijin Chemicals Ltd.)
3) 12 parts by weight of (B) was pelletized with a 40φ (mm) extruder, molded with an injection molding machine, and evaluated by the above-mentioned method. As a result of measuring the glass transition point of this pellet, it was 122 ° C., and good heat resistance was maintained. The light transmittance is maintained at 90% or more, the haze is 0.7%, and the transparency is excellent at 1% or less. The cloud point of this resin was 280 ° C., which was a high cloud point exceeding the molding region.

Comparative Example 1 65 parts by weight of the copolymer (A) obtained in Synthesis Example 1 and an aromatic polycarbonate (manufactured by Teijin Kasei: Panlite AD550)
3) 35 parts by weight of (B) was pelletized with a 40φ (mm) extruder, molded with an injection molding machine, and evaluated in the same manner as in Example 1. As a result of evaluating the transparency of this resin, the entire surface was milky white, the haze was 48%, the light transmittance was 72%, and no transparency was obtained.

Examples 2 to 7 Copolymer (A) produced by Synthesis Examples 1 to 4 and aromatic polycarbonate (manufactured by Teijin Kasei: Panlite AD550)
3) was blended in the proportions shown in Table 2, pelletized,
Evaluation was made in the same manner as in Example 1. As shown in Table 2, the blended resin has a high light transmittance, almost no increase in haze, good transparency, and a cloud point at a high temperature exceeding the molding range.

[0038]

[Table 2] Comparative Examples 2 to 5 Copolymers (A) produced by Synthesis Examples 6 to 7 and an aromatic polycarbonate (manufactured by Teijin Chemicals: Panlite AD55)
03) (B) was blended in the proportions shown in Table 3, and then evaluated in the same manner as in Example 1. The results are shown in Table 3,
All had high haze, and transparency was not obtained. Further, as a result of using the copolymers (A) WO of Synthesis Examples 2 to 3 and changing the blending ratio outside the range of Claim 1, the haze was similarly high and transparency was not obtained.

[0039]

[Table 3]

[0040]

The polymer composition of the present invention has a high glass transition point, excellent transparency, and good compatibility, so that a wide range of molding conditions can be selected. The polymer composition of the present invention can be suitably used for a film, a sheet material, and a molded article such as a lens and an optical disk by utilizing the above characteristics.

Claims (1)

[Claims] 1. A methyl methacrylate unit of 35 to 98% by weight and the following general formula (1): (In the formula, R is a benzyl group or a methylbenzyl group) Methacrylic acid ester unit 1 to 30% by weight,
The following general formula (2): (In the formula, X represents a cyclohexyl group or a methylcyclohexyl group), 1 to 25% by weight of a maleimide unit, and 0 to 10 other copolymerizable vinyl monomer units.
A polymer composition comprising 75 to 95 parts by weight of a copolymer (A) composed of 5% by weight and 5 to 25 parts by weight of an aromatic polycarbonate resin (B).