JPS6241210A - Heat-resistant methyl methacrylate resin - Google Patents

Abstract

PURPOSE:To obtain the titled methyl methacrylate-based resin improved in heat resistance in use and heat stability during melt molding, by copolymerizing a specified methacrylic ester with a fluoroalkyl methacrylate. CONSTITUTION:A methyl methacrylate-based resin comprising 3-5wt% methacrylate ester having an 8C or higher alicyclic hydrocarbon group in the ester moiety and 0.1-5wt% fluoroalkyl methacrylate. Examples of said methacrylic esters include bornyl methacrylate, fencyl methacrylate, l-methyl methacrylate. As the fluoroalkyl methacrylate, one which can form a homopolymer of a softening temperature >=about 70 deg.C is preferable. Preferable examples of the fluoroalkyl methacrylates include 2,2,2-trifluoroethyl methacrylate and 1,1-dimethyl-2,2,3,3-tatrafluoropropyl methacrylate.

Description

[Detailed description of the invention] The present invention relates to a methacrylic resin with excellent heat resistance.

Methacrylic resins have excellent transparency and weather resistance, and have well-balanced properties such as mechanical properties, thermal properties, and moldability, and are used in a wide variety of ways as sheet materials or molding materials. It also has very excellent optical properties, so it can be suitably used as an optical material for substrates for information recording media such as video discs, audio discs, computer information file discs, plastic lenses, and optical fibers. can.

Polymethyl methacrylate is a material commonly used industrially as a methacrylic resin, but the upper limit temperature at which it can be used is approximately 80°C, and at temperatures higher than that, thermal shrinkage increases and deformation occurs. It also has the disadvantage that it causes microstructural fluctuations, which makes it unable to function as an optical material.

In addition, in order to obtain the necessary melt viscosity during molding, approximately 200
When the temperature is higher than 0.degree. C., thermal decomposition tends to occur and coloring tends to occur.

The present invention relates to a methacrylic resin that has improved these two drawbacks, that is, has improved heat resistance during use and thermal stability during melt molding.

That is, the present invention contains 3 to 50% by weight of a methacrylic ester having an alicyclic hydrocarbon group having 8 or more carbon atoms in the ester moiety, 0.1 to 5% by weight of fluoroalkyl methacrylate;
The present invention relates to a methacrylic resin with improved heat resistance and thermal stability, which is mainly composed of less than 1% methyl methacrylate.

Examples of methacrylic acid esters having an alicyclic hydrocarbon group having 8 or more carbon atoms in the ester moiety used in the present invention include bornyl methacrylate, fentyl methacrylate,
Examples include l-menthyl methacrylate, adamantyl methacrylate, and dimethyladamantyl methacrylate.

Another important monomer used in the present invention, fluoroalkyl methacrylate, preferably has a homopolymer softening temperature of about 70°C or higher.

Preferred examples of fluoroalkyl methacrylate used in the present invention include 2,2.2-)lifluoroethyl methacrylate and 1,1,1,3,3.3 methacrylate.
-hexafluoro-2-propyl, methacrylic acid 1.1
-diethyl-2,2,3,4,4,4-hexafluoro=1-butyl, 1-propyl methacrylate-2°2.3
, 4.4.4-hexafluoro-1-butyl, 1.1-dimethyl-3-trifluoromethyl-2 methacrylate,
2,4,4,4-pentafluorobutyl, methacrylic acid 2-) +7 fluoromethyl-2.3,3,3-tetrafluoropropyl, methacrylic acid 1. Aged methyl
Examples include 2.2.3.3-tetrafluoropropyl, perfluoroisopropyl methacrylate, and methacrylic e2-trifluoromethyl-3,3,3-trifluoropropyl.

The feature of the present invention is that a small amount of fluoroalkyl methacrylate, ie, 0.1 to less than 5 times ff11, is used to improve thermal stability during melt molding.

The methacrylic acid ester having an alicyclic hydrocarbon group having 8 or more carbon atoms in the ester moiety is used in an amount of 3 to 50% by weight and 1t%.

When a small amount of fluoroalkyl methacrylate is used as an overfill, flexibility and heat resistance can be satisfied in a well-balanced range within the range of 3 to 50% by weight.

The method for producing the methyl methacrylate resin of the present invention includes:
Any polymerization method such as bulk polymerization, solution polymerization, suspension polymerization, or emulsion polymerization may be used.For optical materials, it is preferable that no foreign substances are mixed in. If necessary, foreign substances such as dust are removed by a p-filtration method or a distillation method. Polymerize.

Examples of radical polymerization initiators include 2,2'-azobis(isobutyronitrile), 1,1-azobis(cyclohexanecarbonitrile), and 2,2'-azobis(2
, 4-dimethylv7leronitrile), azobisisobutanol diacetate, and lauroyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, methyl ethyl ketone peroxide, di-tert-butyl perphthalate, di-tert-butyl Examples include organic peroxides such as peracetate and di-ert-amyl peroxide.

ξThe addition ratio of these polymerization initiators is 0.0 to the monomer.
It is 01 to 1 mole rice cake. In addition, in order to control the molecular weight, tert-butyl, n-butyl, n-octyl, n-dodecyl mercaptan, etc. may be added as a chain transfer agent to the polymerization system in order to control the molecular weight. Methyl methacrylate resin with excellent heat resistance produced by the method of the present invention can be used as a material for equipment as well as for audio discs, video discs, and information recording media for combiators. It can be suitably used for substrates, etc.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to this in any way.

In addition, among the physical property measurement methods in the examples, the total light transmittance is AS
TM D 1003, heat distortion temperature ASTM D648
Measured according to. Further, the yellowness was measured using a digital colorimeter ND-IQI DP model manufactured by Nippon Juishoku Kogyo Co., Ltd.

Example 1 In a stainless steel reactor with an internal volume of 10 mm equipped with a stirrer, 0.8% by weight of droxyethyl cellulose, 0.022% by weight of sodium polymethacrylate, and 0.3% by weight of sodium dihydrogen phosphate were added as suspension stabilizers. ! Add 5 ounces of deionized water in which 1.
0% by weight, 1,1-dimethyl-2,2,3 methacrylate
, 4% by weight of 3-tetrafluoropropyl, 76-fold flcs of methyl methacrylate, and 0.28-fold flcs of n-dodecyl mercaptan and 0.28 weight flcs of lauroyl peroxide were added to the monomer mixture. After adding and dissolving 25% by weight of ffi, the mixture was charged into a reactor and polymerized at a temperature of 83° C. and a stirrer rotation speed of 85° rpm. After about 1 hour, the reaction temperature rose to 95°C. The temperature was further raised to 105°C and maintained for 30 minutes, and then the reactor was cooled. The obtained bead-shaped copolymer was washed with water and dehydrated.

Further, volatile matter was removed by heat treatment at 140° C. for 110 hours under reduced pressure. The polymer was weighed using a thermobalance (Dr. manufactured by Shimadzu Corporation).
When heated at 260° C. for 30 minutes in a nitrogen atmosphere, the weight loss rate was 1.1%.

In addition, after pelletizing the polymer at 230°C,
Injection molded at 0℃ and mold temperature 60℃, 110 x 11
A transparent flat plate of 0 x 2 (ym) was obtained.

When the heat distortion temperature of this injection plate was measured after 7 years in accordance with ASTM D684, it was found to be 120°C. Further, the total light transmittance was 91%, and the degree of yellowness was 0.8.

Examples 2 to 6 Polymers were obtained by adding types and amounts of methacrylic ester and fluoroalkyl methacrylate in the same manner as in Example 1, and then their physical properties were measured. The results are shown in Table 1.

Comparative Example 1 The type and composition of the monomer components were changed in the same manner as in Example 1.
Experiments were conducted with the changes shown in the table. The results are shown in Table 2.

Claims (1)

[Scope of Claims] 1) Methyl methacrylate consisting of 3 to 50% by weight of a methacrylic ester having an alicyclic hydrocarbon group having 8 or more carbon atoms in the ester moiety and 0.1 to less than 5% by weight of fluoroalkyl methacrylate. A heat-resistant methyl methacrylate resin based mainly on 2) A patent in which the methacrylic acid ester having an alicyclic hydrocarbon group having 8 or more carbon atoms in the ester moiety is bornyl methacrylate, fentyl methacrylate, l-menthyl methacrylate, adamantyl methacrylate, or dimethyladamantyl methacrylate. A heat-resistant methyl methacrylate resin according to claim 1. 3) Fluoroalkyl methacrylate is methacrylic acid 2,
2,2-trifluoroethyl, methacrylic acid 1,1,1
, 3,3,3-hexafluoro-2-propyl, 1,1-diethyl-2,2,3,4,4,4-hexafluoro-1-butyl methacrylate, 2-trifluoromethyl-2 methacrylate , 3,3,3-tetrafluoropropyl, 1,1-dimethyl-2,2,3,3-tetrafluoropropyl methacrylate or 2-trifluoromethyl-3,3,3-trifluoropropyl methacrylate. A heat-resistant methyl methacrylate resin according to claim 1.