JPS6346110B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a synthetic resin composition having excellent stability against heat and oxidation. Synthetic resins have excellent physical, chemical, and electrical properties, so they can be processed into molded products, pipes, sheets, films, etc. by various methods such as blow molding, extrusion molding, injection molding, or calendar processing. , used in many fields. It is well known that when synthetic resins are used alone, they deteriorate due to the effects of heat and oxygen during processing or use, and their physical properties deteriorate significantly with phenomena such as softening, embrittlement, and discoloration. . In order to prevent such a phenomenon, various phenol-based, phosphorus-based, sulfur-based, and other antioxidants have been added singly or in combination during the production and processing steps of synthetic resins. For example, 2,6-di-t-butyl-4-methylphenol, n-octadecyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, pentaerythritol-tetrakis [β-(3 , 5-di-t-butyl-4-hydroxyphenyl)propionate], 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-
butyl-4-hydroxybenzyl)benzene,
Using antioxidants such as 1,1,3-tris(2-methyl-4-hydroxy-5-t-butyl)butane or combining these antioxidants with dilaurylthiodipropionate or dimyristylthiodipropionate. Methods such as combinations with pionate or distearylthiodipropionate or those shown in Japanese Patent Publication No. 14703/1983 are known. However, these methods are still not fully satisfactory in terms of thermal and oxidative stability, compatibility and evaporability. As a result of various studies in order to solve these problems, the present inventors have found that by blending a specific phenol compound and a specific sulfur compound into a synthetic resin, we can overcome the conventional combination technology of antioxidants. It has been discovered that a surprising and unexpected synergistic effect can be obtained, and what is even more surprising is that it has extremely superior thermal and oxidative stability compared to conventional technology, and has excellent compatibility with resins, such as bleeding and whitening phenomena. They have found that this is a significant improvement and have arrived at the present invention. That is, the present invention provides a synthetic resin with a compound of the following general formula () and a compound of the general formula () ():()
The present invention provides a stabilized synthetic resin composition which is blended in a ratio of 1:1 to 10 (weight ratio). (In the formula, R represents a branched alkyl group having 4 to 9 carbon atoms, A represents an alkylene group having 1 to 4 carbon atoms,
n represents an integer from 1 to 4. ) (In the formula, X represents an alkyl group having 4 to 20 carbon atoms, and n represents an integer of 1 to 4.) In the compound of general formula () used in the present invention,
In view of its performance as an antioxidant, the substituent R is preferably a tertiary alkyl group branched at the α-position, such as a t-butyl group, a t-amyl group, a t-octyl group, or an α-methyl-cyclohexyl group. Further, the substituent A is preferably an alkylene group having 1 to 3 carbon atoms. Further, n is preferably an integer of 3 to 4, particularly preferably 4. Further, in the compound of general formula (), when n is an integer of 2 or more, X may be the same or different within the same molecule, but it is more advantageous for the synthesis to be the same. Further, n is preferably an integer of 3 to 4, particularly preferably 4, in view of its performance as an antioxidant. Next, Table 1 and Table 2 show typical examples of compounds of general formula () and compounds of general formula () used in the present invention.

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【table】

[Table] The above compounds of general formula () are pentaerythritol and general formula () (In the formula, R and A have the same meanings as above.) It can be produced by reacting the compound represented by the formula or its lower alkyl ester or its acid chloride by a known method. In the synthetic resin composition of the present invention, the total amount of the compound of formula () and the compound of formula () added is usually 0.001 to 5 parts by weight, preferably 0.01 to 2 parts by weight, based on 100 parts by weight of the synthetic resin. The weight ratio of the compound of formula () to the compound of formula () is usually 1 to 10 to 1 of the compound of formula (), but 2 to 1.
6 is particularly preferred. In the present invention, in order to blend the compounds of the formulas () and () with the synthetic resin, the known equipment and operation methods for mixing and blending stabilizers, pigments, fillers, etc. into thermoplastic resins can be applied almost as they are. The synthetic resin composition of the present invention may contain other additives such as ultraviolet absorbers, light stabilizers, antioxidants, metal soaps, pigments, and fillers. In particular, by adding an ultraviolet absorber, a hindered amine light stabilizer, etc., better light resistance can be imparted. The synthetic resins stabilized by the present invention include:
Polyolefin resin, ABS resin, polystyrene resin, high impact polystyrene resin, polyamide resin, polyester resin, polycarbonate resin,
There are polyacetal resins, etc., and it is particularly effective for polyolefin resins. Next, the present invention will be explained in detail with reference to Reference Examples and Examples, but the present invention is not limited thereto. Reference Example 1 Synthesis of tetrakis[2-(2-methyl-4-t-butyl-5-hydroxyphenyl)acetyloxymethyl]-methane (-1 compound) 2-methyl-4- t
-butyl-5-hydroxyphenyl-methyl acetate
Add 128.6g and 16.5g of pentaerythritol,
The air in the reaction vessel is replaced with dry nitrogen, and 0.5 g of sodium methoxide is added. The reaction is carried out at 130°C for 2 hours, and then at 140-150°C for 10 hours under a reduced pressure of 20 mmHg. During this reaction, 1.5 g of sodium methoxide is added in three equal portions as the reaction progresses. After the reaction is completed, the internal temperature is cooled to 80°C and neutralized with glacial acetic acid. Add toluene to this, wash with water, and dehydrate with anhydrous sodium sulfate. Then, removing the solvent under reduced pressure gives 101.4
g (yield: 88%) to obtain tetrakis[2-(2-methyl-4-t-butyl-5-hydroxyphenyl)acetyloxymethyl]-methane as a pale yellow viscous liquid. When this is recrystallized from n-heptane,
White crystals with a mp of 89-91°C are obtained. Elemental analysis value (as C ₅₇ H ₇₆ O ₁₂ ) C (%) H (%) Calculated value 71.8 8.0 Measured value 71.7 8.2 'H-NMR CDCl ₃ δ (ppm) 1.33 (36H, S), 2.80 (12H, S ), 3.45 (8H,
S), 3.79 (8H, S), 5.47 (4H, S), 6.25 (4H,
S), 6.99 (4H, S) Example 1 After mixing the following formulation with a mixer for 5 minutes,
The compound obtained by melt-kneading with a mixing roll at 180°C was molded into a sheet with a thickness of 1 mm using a hot press at 210°C, and a test piece of 40 x 40 x 1 mm was prepared. 30 of the specimen area in a gear oven at 150 °C
The thermal and oxidative stability was evaluated by measuring the time until % embrittlement. The results are shown in Table-3. <Formulation> Unstabilized polypropylene resin 100 parts by weight Calcium stearate 0.1 Test compound Variables In the table, AO-1 to AO-8 indicate the following compounds. AO-1 2,6-di-t-butyl-4-methylphenol AO-2 n-octadecyl-β-(3,5-
Di-t-butyl-4-hydroxyphenyl)propionate AO-3 Pentaerythritol-tetrakis [β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] AO-4 1,1,3 -Tris(2-methyl-
4-Hydroxy-5-t-butylphenyl)butane AO-5 Dilaurylthiodipropionate AO-6 Distearylthiodipropionate AO-7 Distearylpentaerythritol diphosphite AO-8 Tris(2,4-di- t-butylphenyl) phosphite

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【table】

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[Table] Example 2 Put 100 parts by weight of unstabilized ABS resin powder into a crusher and disperse with an appropriate amount of methanol. A test compound was added thereto, and methanol was evaporated while mixing, and the resulting ABS resin powder was used as a test sample. Thermal and oxidative stability was evaluated by the degree of discoloration of ABS resin powder after aging in a gear oven at 180°C. The results are shown in Table 4.

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Claims (1)

[Claims] 1. Compounds of the following general formula () and compounds of the general formula () are blended in a synthetic resin in a ratio of ():()=1:1 to 10 (weight ratio). A stabilized synthetic resin composition. (In the formula, R represents a branched alkyl group having 4 to 9 carbon atoms, A represents an alkylene group having 1 to 4 carbon atoms,
n represents an integer from 1 to 4. ) (In the formula, X represents an alkyl group having 4 to 20 carbon atoms, and n represents an integer of 1 to 4.)