JPS58104939A - Methacrylic resin composition - Google Patents

Abstract

PURPOSE:To prepare a composition having excellent optical properties and impact resistance as well as remarkably reduced moisture absorption, by compounding a copolymer composed of methyl methacrylate and cyclohexyl methacrylate with an impact-resistant acrylic resin. CONSTITUTION:The objective composition is prepared by compounding (A) 70- 98pts.wt., preferably 80-95pts.wt. of a copolymer composed of (a) 50-85wt% (in terms of monomer) methyl methacrylate, (b) 15-50wt% cyclohexyl methacrylate and (c) 0-10% other vinyl monomer copolymerizable therewith with (B) 2-30pts.wt., preferably 5-20pts.wt. of an impact-resistant acrylic resin containing a crosslinked acrylic acid ester polymer as the rubber component. The heat decomposition resistance of the composition can be improved by using a vinyl compound, preferably a compound containing 0.2-10% alkyl acrylate having 1-8C alkyl, as a component of the component (A).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a methacrylic resin composition □Methacrylic resin whose main component is methyl methacrylate has extremely excellent properties in terms of transparency and weather resistance.
mechanical iit.

It has well-balanced properties such as thermal properties and moldability, and by taking advantage of these characteristics, it can be used as a sheet material or molding material for signboards, lighting equipment parts, electrical equipment parts, automobile parts, and maintenance materials. It is used in many ways as currency.

Recently, methacrylic resin has begun to be used as a material for information recording media such as video discs, audio discs, computer information, file discs, etc., taking advantage of its transparency and other excellent properties.In particular, methacrylic resin has been used as a material for information recording media, such as substrates for information recording media. The use of sheets and films made of vinyl chloride resin, polystyrene, methacrylic resin, etc. has been proposed because they are easy to handle with equipment, but methacrylic on the other side has excellent light transmittance and is less susceptible to scratches than vinyl chloride resin. Methacrylic resin is particularly suitable for information recording media that are optically reproduced using laser light because it has characteristics such as being resistant to flaking, having a low birefringence, and having good surface precision and a beautiful finish.

However, methacrylic resin is polyolefin thread resin,
It has relatively high hygroscopicity compared to polystyrene resins, and may cause dimensional changes due to moisture absorption, warpage of molded products, or cracks due to long repeated cycles of moisture absorption and drying, which limits the use of ordinary methacrylic resins. There are some fields where In particular, information such as video discs, audio discs, large-capacity image files, large-capacity computer disk memories, etc. □ As recording material, molded products should not warp, etc.
A high degree of dimensional stability is required, and there is a demand for the provision of methacrylic resins with reduced hygroscopicity.◎ The hygroscopicity problem of methacrylic resins is to some extent an inherent property caused by the chemical structure of the polymer. So far, there have been few proposals regarding the reforming method, and of course, the current situation is that it has not been commercialized.

In view of the current situation, the present inventors conducted intensive research to improve the hygroscopicity of methacrylic resin, and to develop a methacrylic resin with excellent mechanical strength and optical properties.Methyl methacrylate By co-merging cyclohexyl methacrylate and other copolymerizable vinyl monomers with methyl methacrylate, the hygroscopicity of methyl methacrylate polymer, which has completely different optical properties than previously known, has been significantly reduced. In addition, we discovered a completely new function and effect in which methyl methacrylate, cyclohexyl methacrylate, and other copolymerizable vinyls are used as specific components of copolymer (1) and impact-resistant acrylic resin (II). In the blends within the range of two direct materials and shaped materials, "i (6 brightness, 1:
1 It has the excellent properties inherent to methacrylic resin, such as weather resistance, mechanical properties, thermal properties, and molding DII properties, and its hygroscopicity is significantly lower than that of ordinary methacrylic resin, making it suitable for information recording media. The present invention was achieved by discovering that a composition most suitable for the material can be obtained□ That is, the present invention is based on methyl methacrylate (5oNzj weight), cyclohexyl methacrylate (Jl)/! in terms of monomer components. 70 to 10 parts by weight in a co-enriched polymer consisting of other vinyl monomers (C) copolymerizable with 0 to 10% by weight and 0 to 10% by weight and a crosslinked acrylic acid ester polymer. It is a methacrylic resin composition consisting of 2 to 30 parts by weight (total 100 parts by weight) of impact-resistant acrylic 1 resin (II) containing as a rubber component cyclohexyl methacrylate used as a copolymerization component of the methacrylic resin of the present invention. It has been known for some time that homopolymers have a higher refractive index than other methacrylate polymers and excellent light dispersion properties, so they have excellent basic performance as plastic lens materials. ,
Homopolymers of cyclohexyl methacrylate are very
However, the general molding process is also difficult, and there are extremely serious problems in putting it into practical use. The present invention is based on the discovery that a blend of a yarn copolymer and an acrylic yarn impact-resistant resin provides a methacrylic resin with excellent optical properties, low moisture absorption, and improved impact resistance. In the copolymer (l), the ratio of methyl metata-11) phosphate (4) to 30~gs1 @%G)? This is the composition range necessary for imparting the optical properties, weather resistance, mechanical properties, thermal properties, or moldability inherent to methacrylic resin to the copolymer prepared in 1, and more preferably SS.
~tS wt%.

If the usage ratio of methyl methacrylate component is less than SO content%, the above properties will be impaired, and conversely, if it exceeds ZS content%, the effect of improving hygroscopicity will be reduced. 1. Cyclohexyl methacrylate Usage rate of (B)/! r-jO weight% is the amount of component necessary to improve the hygroscopicity of the resulting copolymer σ), and more preferably 10-13% by weight in the 073 overlapping groove, the hygroscopicity improvement is This is because if the quality effect is not sufficient and the weight exceeds the SO type weight, the mechanical strength will be greatly reduced.In addition, other vinyl monomers that can be copolymerized with Examples of different isomers of the polymer (Q) include methyl acrylate, ethyl acrylate, butyl acrylate, styrene, acrylonitrile, etc., and the proportion used is preferably 10% or less.

In particular, when the copolymer of the present invention is put to practical use as a molding material, in order to improve the thermal decomposition resistance of the copolymer in consideration of molding in a relatively high temperature range, 0.2 to 10 g% of a vinyl compound is added. It is preferable to use (C). If the proportion of □O)) used is less than the weight of a, the heat decomposition resistance will be insufficient, and IO, :':.

If it exceeds % by weight, there will be an interlayer that will reduce transparency, hygroscopicity, and heat deformation resistance.◎The vinyl compound (C) contains an alkyl group with carbon number/-g. It is preferable to use an alkyl acrylate such as ethyl acrylate, butyl acrylate, 1-ethylhexyl for acrylic acid, etc. from the viewpoint of heat decomposition resistance, hygroscopicity, and heat deformation resistance.

The proportion of 70-9g weight used in the copolymer of the present invention is g
& for modifying wettability, more preferably g
O~95 fits. This is because if the proportion of copolymer (IJ) used is less than 70 parts by weight, the effect of improving hygroscopicity is small, and if it is more than 9 g weight, no improvement in mechanical strength can be expected.

The proportion of 1 to 30 parts by weight of the impact-resistant resin (n) containing the crosslinked acrylic acid ester main composite of the present invention as a rubber component is for improving mechanical strength, and is less than - It is better than □ that no improvement in mechanical strength can be expected, and if it is more than 3q parts, the effect of modifying hygroscopicity is small and J optical properties are poor.

Preferably, the amount is j-10 parts. As a specific method for producing an impact-resistant resin containing a crosslinked acrylic acid ester-based polymer as a rubber component, for example, first, ethyl acrylate, n-
Acrylic acid esters such as butyl acrylate, -monoethylhexyl acrylate, etc. 70~/DO polyester, methyl methacrylate copolymerizable with this, acrylonitrile,
Monomers such as styrene θ~30* weight ratio and crosslinkable monomers a/~SJ containing at least 0 return element-carbon bonds in 7 molecules! A monomer mixture consisting of a different amount is emulsion polymerized to produce a frame 11 rubber latex having a particle size of 1203 to ajμ. Next, in the presence of this latex, monomers such as acrylonitrile, styrene, and methyl methacrylate are graft-polymerized to obtain a latte-like impact-resistant resin containing a crosslinked acrylic acid ester polymer as a rubber component.1 This is solidified. ＼The resin of the component used in the present invention can be obtained by drying. □ Commercially available resins of this type include [Dialac-A] manufactured by Mitsubishi Rayon Co., Ltd.
J and "Acrivet IR", "Plexiglas DR" by Rohm and Haas Oboro, "
"Pytarakuzu" etc.

The above are the essential ingredients and blending ratio of the present invention, but in order to specifically obtain the composition of the present invention, after weighing the above-mentioned resin within the scope of the present invention, use a Henschel mixer or After mixing in a mold blender, it may be pelletized using an extruder, or after dissolving the 1-crosslinked acrylic acid ester yarn body in an impact-resistant resin monomer mixture containing a rubber component,
It can also be obtained by bulk Togane or suspension polymerization.Dyeing and pigments, ultraviolet absorbers, oxidation stabilizers, etc. can be added to the composition of the present invention as required. More specifically, Example 7 to Comparative Example 1 Into a separable flask equipped with a condenser, a stirrer, and a thermometer, methyl methacrylate, nitrate, and obrovil methacrylate were added as a dispersant. Copolymer Q! Add dissolved water 30009 and separate! Ill-ordered methyl methacrylate! A mixture obtained by dissolving 3 g of n-octyl mercaptan and 119 azobisisobutyonitrile in a monomer mixture of 30 g of cyclohexylda metatallylate and 7j9 of butyl acrylate was charged into a separable flask and heated at a temperature of gOC at a rotational speed of J. j Or
After polymerization for 1 hour while stirring at 100 pm, polymerization was carried out at 91C for 3 hours, and Beasts) IR-H-70 was blended in the ratio shown in Table 1, mixed in a Henschel mixer, and then heated in one cylinder at one temperature. ,l! Extruded with rC and pelletized ◎
The extruded pellet was then dried in a vacuum cleaner for 4' hours. The results are shown in Table 2.

□.

Example 3 In exactly the same manner as in Example 1, methyl methacrylate voo
g, cyclohexyl methacrylate j-s9, methacrylic! ! --Blending 920 g of the obtained polymer with a monomer mixture of ethylhexyl Sg and Mitsubishi Rayon Co., Ltd. Group Acrybet IR-H-RI0 109 in a ■ type blender, and then using a cylinder Shimadoko 1IOC. Extruded into pellets. The physical properties of this reamer were measured and the results are shown in Table 3.

Claims (1)

[Claims] l Methyl methacrylate s0~ in terms of monomer components
Sj weight, citalyhexyl methacrylate)/jt-
70 to 98 parts by weight of a copolymer consisting of On-10 and other vinyl monomers (2) and A methacrylic resin composition consisting of impact-resistant acrylic resin as a rubber component 1) 2 to 30 parts by weight (total 100 parts by weight) The vinyl monomer (C) constituting the copolymer (1) is the prime number / A/I is a copolymer containing an alkyl acrylate a having an alkyl group of ~70% by weight, and is suitable for molding information recording bodies.
# Scope of fraud-seeking methacrylic resin composition according to item 1.