JPS60123547A - Thermally stabilized methacrylate copolymer composition - Google Patents

Abstract

PURPOSE:The titled composition that is obtained by adding a phosphaphenanthlene to a specific methacrylate copolymer, thus showing remarkably improved thermal stability and having effect to inhibiting discoloration on forming with heat. CONSTITUTION:(A) 100pts.wt. of a methacrylate copolymer consisting of 35- 90wt% of methyl methacrylate, 5-35wt% of styrene and 5-30wt% of maleic anhydride and having a melt-flow index of 0.1-15g/10min. are combined with (B) 0.01-2, preferably 0.05-1pt.wt. of a phosphanaphthalene of the formula (R1 is H, OH, 1-4C alkyl, 1-4C alkoxy; R2, R3 are H, l-8C alkyl, 1-8C alkoxy) and (C) 0.01-1, preferably 0.05-0.5pt.wt. of at least one selected from hindered phenolic compounds, thiodipropionic acids and phosphite esters.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to thermally stabilized methacrylic copolymer compositions. More specifically, the present invention relates to a methacrylic copolymer composition comprising methyl methacrylate, styrene, and maleic anhydride that has improved thermal coloring and thermal deterioration due to oxidative decomposition during molding at high temperatures.

Methyl methacrylate-styrene-mannic anhydride copolymer maintains excellent mechanical properties, weather resistance, and transparency equivalent to conventional methacrylic resins, as well as excellent heat resistance that conventional methacrylic resins cannot have. Oz-C has recently attracted much attention as a resin with Let me give you an example: Automatic Engineering Department 5. Tojie. ;-In the case of LED lamps, higher heat resistance is required compared to conventional lamps due to the increased size of the lamp itself, increased heat generation due to increased illuminance, and thinner walls due to cost reduction. It is expected to be used in parts whose temperature rises significantly under direct sunlight, such as meter covers for two-wheeled vehicles (motorcycles) and covers for water heaters that use solar thermal energy.

However, the composition of methyl methacrylate-styrene-maleic anhydride copolymers with high heat resistance is generally methyl methacrylate/styrene/maleic anhydride = 35-901.
5-3515-30 (wt%) and has the disadvantage that it tends to gradually discolor when molded at high temperatures compared to ordinary methacrylic resins. The problem of thermal discoloration during molding due to long residence times at high temperatures has come to the fore. However, even if general-purpose phenolic compounds, amine compounds, metal soaps, phosphite compounds, phosphoric acid ester compounds, and sulfur-containing compounds are added as thermal coloring and thermal deterioration inhibitors for thermoplastic resins, the thermal stability remains. No remarkable effect was obtained, and the combined use of these compounds also did not show a sufficient effect on thermal coloring.

In view of the above-mentioned current situation, the present inventors conducted intensive studies on a highly heat-resistant methacrylic copolymer composition that has an excellent coloration prevention effect even during heat-forming processing at high temperatures. The present invention was based on the discovery that the thermal stability was significantly improved by adding and mixing a phosphorus compound.

That is, the present invention uses methyl methacrylate of 35 to 90% by weight, methacrylate of 2 to 35% by weight, and maleic anhydride of 5 to 3% by weight.
General formula (A) 1 (wherein R1 is a hydrogen atom, a hydroxyl group, a furkyl group having 4 or less carbon atoms, an alkoxy group having 4 or less carbon atoms) per 100 parts by weight of a methacrylic copolymer containing , R2 and R3 each represent a hydrogen atom, an alkyl group having 8 or less carbon atoms, or an alkoxy group having 8 or less carbon atoms.
．． This is a heat-stabilized methacrylic copolymer composition prepared by adding and mixing 01 to 2.0 parts by weight.

The methacrylic copolymer of the present invention is methyl methacrylate 3
5-90% by weight, styrene 5-3s: *mass and maleic anhydride 5-30% by weight, more preferably A
It is called STMDI 238 (1 condition). ) A specific example of the phosphaphenanthrene compound of the present invention represented by the general formula (A) is shown below as a formula 2. (
) indicates an abbreviation.

The amount of the phosphaphenanthrene compound of the present invention added is 0 to 100 parts by weight of the methacrylic copolymer (1).
．． 01 to 2.0 parts by weight, more preferably 0.05 to 1.0 parts by weight.
It is 0 parts by weight. When the amount of the fumesphaphenanthrene compound is less than 0.01 part by weight, no thermal stabilizing effect is observed,
Moreover, when the amount exceeds 2.0 parts by weight, the coloring prevention effect is good, but the heat distortion temperature decreases, which is not preferable.

The present invention also provides 0.01 to 2.0 parts by weight of at least one phosphaphenanthrene compound represented by the general formula (A) and a hinderer to 100 parts by weight of the methacrylic copolymer (1). At least one of dophenol compounds, thiodipropionic acid compounds, and phosphite compounds. This is a thermally stabilized methacrylic copolymer composition prepared by adding and mixing ONN Gunbe.

At least one of these phosphaphenanthrene compounds of the present invention and at least one of a hindered phenol compound, a thiodipropionic acid compound, and a phosphite compound? ', it has been found that by combining one type of phosphaphenanthrene compound, an effect equal to or greater than that of the phosphaphenanthrene compound alone can be exhibited. This means that if a hindered phenol compound, thiodipropionic acid compound, or phosphite compound is used alone, all (
This is a surprising phenomenon considering that it had no effect.

Specific examples of hindered phenol compounds include 2,6-di-t-butyl-4-methylphenol, 2,
4.6-) So-t-butylphenol, 2.2'-methylenebis-(4-methyl-6-t-butylphenol)
, 1,3.5-)dimethyl-2,4,,6-)lis-(
3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1,1-bis-(2-hydroxy-3,5-dimethylphenyl)3,5.5-)! J methylhexane,
Tetrakis-[methylene-(3,5-di-t-butyl-
4-hydroxyhydrocinnamate)] methane, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenol) flobionate, 4゜4'-methylenebis-(2-t-butyl-6-methyl phenol), 4
．． 4'-Thiobis-(3-methyl-6-t-butylphenol), 4,4'-Thiohis-(3-methyl-s, -
t-7' tylphenol) and the like.

Specific examples of the thiodipropionic acid-based compounds include dioxin thiodibu-bionate, dilaurylthiodibu-bionate, distearylthiodibu-bionate, and the like.

Specific examples of phosphite compounds include triphenyl phosphite, tris(nonylphenyl) phosphite, tristearyl phosphite, diphenyl nonylph, 1-nyl phosphite, diphenylisodecyl phosphite, etc. .

These hindered phenol compounds, thiodipropionic acid compounds and phosphite ester compounds satisfy the present invention only when used in combination with a phosphaphenanthrene compound. □When used together, methacrylic copolymer (1
) 100 parts by weight, 0 phosphaphenanthrene compounds
．． 01 to 2.0 parts by weight, more preferably 0.05 to 1.0 parts by weight.
0 parts by weight, one or a combination of two or more of hindered phenol compounds, thiodibourbione compounds, and phosphite compounds from 0.01 to 0.01 parts by weight.
The amount is 1.0 parts by weight, more preferably 0.05 to 0.5 parts by weight. If the amount exceeds 1.0 parts by weight, the heat distortion temperature decreases and the effect on thermal coloring and sheet deterioration of the methacrylic copolymer (1) is maintained, but coloring due to the additive itself increases, which is not preferable. Although not limited, the amount of the phosphaphenanthrene compound added is preferably greater than the amount of the hindered phenol compound, thiodipropionic acid compound, or phosphite compound.

The composition of the present invention may contain known plasticizers, lubricants,
It can contain dyes and pigments, stabilizers, ultraviolet absorbers, etc.

Further, the method for obtaining the composition of the present invention is not particularly limited, and for example, a Henschel mixer may be used to obtain the methacrylic copolymer (
By any method, such as mixing 1) and additives and melt-kneading them using an extruder to form pellets, or sprinkling the additives onto pellets of methacrylic copolymer (1) using a spreading agent, etc. It is also possible to mix

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to the scope of these Examples. Parts and parts in the examples represent parts and weight, respectively. As a measure of thermal coloring, the b value measured with a Hunter colorimeter was used. The total light transmittance and haze are ASTM D1003, and the heat distortion temperature is ASTM D648 (load: 264 p).

s, i,), melt flow index is ASTM D1
238 (one condition).

Example 1 Comprised of 75% methyl methacrylate, 15% styrene, and 10% maleic anhydride, with a melt flow index of 2.
0. ! After mixing 100 parts of methacrylic copolymer with a ratio of i'/10 minutes and 0.5 parts of a phosphaphenanthrene compound represented by (A-1) in a Henschel mixer, the cylinder temperature was increased using a 400 extruder. The mixture was melt-kneaded at 230°C to obtain pellets. This pellet was injection molded using an injection molding machine at a cylinder temperature of 260°C. The heat deformation temperature of the obtained molded piece was 111° C., the total light transmittance of the 6-dragon plate was 90.5%, the haze was 0.7%, and the colorimetric b value was 2.7.

Furthermore, the heat distortion temperature of a molded piece obtained in exactly the same manner except that the phosphaphenanthrene compound (A-1) was removed was 110°C, and the total light transmittance haze and b value of the 6u plate were 89.5. %, 0.7%, and 6.2.

Example 2 Consisting of 72% methyl methacrylate, 17% styrene, and 11% maleic anhydride, with a melt flow index of s,
After mixing 100 parts of the methacrylic copolymer (OyZio) and 1.0 part of the phosphaphenanthrene compound represented by (A-4) in a Henschel mixer,
The mixture was melt-mixed using a DA extruder at a cylinder temperature of 225° C. to obtain pellets. This pellet was injection molded using an injection molding machine at a cylinder temperature of 260°C. The heat deformation temperature of the obtained molded piece was 113° C., the total light transmittance J of the 6 mm plate was 89.8%, the haze was 0.8%, and the b value was 2.9.

Furthermore, the heat deformation temperature of a molded piece obtained in exactly the same manner except that the phosphaphenanthrene compound (A-4) was removed was 114°C, and the total light transmittance, haze, and b of the 6 rnyn plate were
The values were 87.3, 1.1, and 7.1, respectively.

Example 3 Made of 83% methyl meccrylate, 10% styrene, 7% maleic anhydride, and has a melt flow index of 1.5.
Is it g/10 minutes? 100 parts of tacryl copolymer and (
After mixing 0.2 f'J5 of the phosphaphenanthrene compound represented by A'-8) in a Henschel mixer, a 40 Da extruder was used to prepare the cylinder at a temperature of 240°C.
The mixture was melted and kneaded to obtain a pellet. This pellet was injection molded using an injection molding machine at a cylinder temperature of 270°C. The heat deformation temperature of the obtained molded piece was 107° C., the total light transmittance of the 6u plate was 191.2%, the haze was 0.5 cm, and the b value was 2.4.

In addition, the heat distortion temperature of a molded piece obtained in exactly the same manner except that the phosphaphenanthrene compound (A-8) was removed was 107°C, and the total light transmittance, haze, and b of the 6 nm plate were as follows.
The values were 90.2%, 0.9%, and 4.5, respectively.

Examples 4 to 21 The type and amount of phosphaphenanthrene compound added to 100 parts of the same methacrylic copolymer as in Example 1,
The types and addition 11 of the hindered phenol compound, thiodipropionic acid compound, and phosphite compound were mixed in a Henschel mixer, and then pelletized and injected in the same manner as in Example 1. Molding was performed to obtain a molded piece. These results are shown in Table 1. .

Comparative Examples 1 to 10 A hindered phenol compound, a thiodipropionic acid compound, a phosphite compound, and its geothermal plastic resin as a heat stabilizer were added to 100 parts of the same methacrylic copolymer as in the example. A molded piece was obtained by pelletizing and injection molding in the same manner as in Example 1 using general-purpose additives. These results are shown in Table 2.

The saturating agents used in Tables 1 and 2 are each represented by the following abbreviations.

(B-1) 2.6-di-t-butyl-4-methylphenol (B-2) 2.2'-methylenebis-(4-methyl-
6-t-butylphenol) (B-3) Tetrakis-[methylene-(3゜5-di-L-butyl-4-hydroxyhydrocinnamate)]methane (B-4) 4.4'-Thiobis-(2- -Butyl-
6-methylphenol) (C-1) dilaurylthiodipropionate (C-2
) Distearyl thiodipropionate (D-1)) Riphenyl phosphite (D-2) Diphenylindecyl phosphite (E-1)
) Di-t-dodecyl disulfide (E-2) Dioctyltin dilaurate (E-3) Calcium stearate Table 1

Claims (1)

Scope of Claims (General formula for 2 parts per 100 parts of methacrylic copolymer consisting of 35-90% by weight of 11 methyl methacrylate, 5-35% by weight of Step 2, and 5-30% by weight of maleic anhydride) (A) 1 (However, in the formula, R1 is a hydrogen atom, a hydroxyl group, an alkyl group having up to a4 carbon atoms, an alkoxy group having up to 4 carbon atoms, and R2 and R3 are each a hydrogen atom, a furkyl group having up to 8 carbon atoms, or a carbon A thermally stabilized methacrylic copolymer composition prepared by adding and mixing 0.01 to 2.0 parts by weight of at least one phosphaphenanthrene compound represented by the number 8 or less. (2) Methyl methacrylate 35-90% by weight, styrene 5-35% by weight and maninic anhydride 5-30% by weight
0.01 to 2.0 parts by weight of at least one type of fumesphaphenanthrene compound represented by the general formula (A) and a hindered phenol compound to 100 parts by weight of the methacrylic copolymer consisting of , at least one of thiodipropionic acid compounds and phosphite compounds
．． A thermally stabilized methacrylic copolymer composition prepared by adding and mixing 01 to 1.0 parts by weight.