JPS6136345A - Ethylene-propylene based vulcanized rubber composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by incorporating hydrous or anhydrous silicic acid with a specific stabilizer, and vulcanizing the resultant mixture with a peroxide, and having improved weather resistance and bright hue. CONSTITUTION:An ethylene-propylene based vulcanized rubber composition obtained by incorporating (A) 100pts.wt. ethylene-propylene based rubber with (B) 5-100pts.wt. hydrous silicic acid and/or anhydrous silicic acid, (C) 0.01-3pts.wt. compound expressed by formula I or II (R1 is 1-3C alkyl; R2 is 6-10C alkyl; R3 is 1-3C alkyl; n is a real number 1-5) and (D) 0-3pts.wt. compound expressed by formula III or IV (R4 is 1-9C alkyl; R5 is 1-6 alkyl; m is an integer 1-6), and vulcanizing the resultant mixture with a peroxide.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ethylene-propylene vulcanized rubber composition having excellent weather resistance and a clear hue.

Ethylene-propylene rubber or ethylene-propylene-nonconjugated diene rubber (hereinafter collectively referred to as ethylene-propylene rubber) has better weather resistance than general-purpose rubbers such as natural rubber, styrene-butadiene rubber, butadiene rubber, and isoprene rubber. Due to its excellent heat resistance and heat resistance, it is used for automobile exterior comb parts, engine parts,
It is widely used in various fields such as building materials, but conventional products are black products containing carbon black.
White formulations containing reinforcing agents or fillers other than carbon black, such as hydrous silicic acid, anhydrous silicic acid, calcium carbonate, clay, etc., have superior heat resistance compared to natural rubber and general-purpose synthetic rubber; It is inferior in terms of weather resistance and heat resistance I compared to black formulations.

For this reason, in conventional white formulations, 10 to 5 parts by weight of titanium white, especially rutile type titanium white, which has an ultraviolet shielding effect, is used.
Titanium white has been added to improve weather resistance, but since titanium white has a hiding power, it is difficult to add a dull, dull hue, especially in the case of colored compositions containing pigments and/or dyes. This resulted in a sulfur rubber composition, and only a product with low commercial value could be obtained.

For these reasons, the present inventors developed an Etiμ material that has excellent weather resistance and a clear hue.

As a result of extensive research to develop an ethylene-propylene-based vulcanized rubber composition, we added specific amounts of hydrated silicic acid and/or anhydrous silicic acid, and a specific stabilizer to ethylene-propylene-based rubber. It was discovered that a rubber composition with excellent weather resistance and a clear hue could be obtained by oxidation vulcanization, and the present invention was accomplished based on this discovery.

That is, the present invention provides ethylene-propylene rubber 100
Per part by weight, 5 to 100 parts by weight of hydrated silicic acid and/or anhydrous silicic acid, and 0.01 to 100 parts by weight of at least one compound selected from the compounds represented by the following general formulas (Il, f■).
3 parts by weight and 0 to 8 parts by weight of at least one compound selected from the following general formula σ [11, (IVI). The present invention provides an ethylene-propylene-based vulcanized rubber composition.

General formula (Il (wherein, R1 represents a C1-3 alkyl group) General formula (II) (wherein, R2 is a C6-, alkyl group, R3 is a C8-3 alkyl group)
3, and n represents a real number of 1 to 5. (In the formula, R6 represents an alkyl group of C1 to 1.) General formula 〇YI (In the formula, R5 represents an alkyl group of C1 to 6, and m represents an integer of 1 to G.) The amount used is usually 5 to 100 parts by weight per 100 parts by weight of ethylene-propylene rubber in order to maintain good color clarity and physical properties of the vulcanized rubber composition.

In the present invention, the reinforcing agent and filler are not limited to hydrated silicic acid and hydrated silicic acid, but other white reinforcing agents and white fillers are used in a ratio of about 1 to hydrated silicic acid and/or anhydrous silicic acid.
It may be added in a range of 0% or less.

The present invention uses stabilizers represented by the general formulas fI) to GV) in addition to the above-mentioned hydrous silicic acid and/or anhydrous silicic acid. Among these various stabilizers,
At least one compound selected from the compounds represented by the general formula (Il, (11) is an essential component, and the amount used is 0.01 parts by weight per 100 parts by weight of ethylene-propylene rubber.
~3 parts by weight. If the amount is less than this range, the heat resistance and weather resistance will not be sufficient, and if it exceeds this range, an unnecessary amount will be used and it will be uneconomical.

In addition, in the compound represented by the general formula, the molecular terminal may be another protecting group in place of the hydrogen atom, or may be a salt of the amine, and these may be treated to improve the effect.

Although the compounds represented by general formula bait) and σ) are not essential components in the present invention and are not necessarily required, the addition of at least one selected from these compounds is effective in further improving the effect, and generally It is used in an amount of 8 parts by weight or less per 100 parts by weight of ethylene-propylene rubber.

All of the compounds represented by the general formulas (Il to α) are known as stabilizers for polyolefin plastics (for example, Japanese Patent Publication No. 47-27624, Japanese Patent Application Laid-Open No. 1983-1998).
No. 6-62885, JP-A No. 51-5849, etc.) are not known at all as stabilizers for vulcanized rubber compositions.

The vulcanized rubber composition has various additives such as reinforcing agents, vulcanizing agents, and vulcanization accelerators, and then undergoes a vulcanization process, which makes it different from ordinary polyolefin resins not only in the type of polymer but also in composition and composition. Considering the large differences in processing steps,
It is surprising that the present invention exhibits excellent effects on a rubber composition specified as ethylene-propylene rubber containing hydrous silicic acid and/or anhydrous silicic acid.

An ethylene/propylene unvulcanized rubber composition containing hydrated silicic acid and/or anhydrous silicic acid and the above-mentioned stabilizer is:
Next, it is vulcanized, but in the present invention, peroxide vulcanization is performed because a vulcanized rubber composition with a clear hue cannot be obtained by a vulcanization method such as sulfur vulcanization. The peroxide used for this purpose is not particularly limited as long as it is an organic peroxide, and one or more organic peroxides such as diacyl peroxide, dialkyl peroxide, peroxy ester, and perketal can be used. can. Further, if necessary, ethylene dimethacrylate, trimethylpropane trimethacrylate, triallyl isocyanate, etc. can be added as an auxiliary agent for peroxide vulcanization.

The vulcanization method itself in this peroxide vulcanization is not related to the present invention 1.
This is not specified, and conventionally known methods are applied.

In the present invention, the organic pigment and/or organic dye used for coloring the vulcanized rubber composition are not particularly limited as long as they are commonly used. Furthermore, if necessary, known auxiliary materials for rubber such as softeners, plasticizers, processing aids, zinc oxide, stearic acid, etc. can be added, but it is preferable to use materials that do not color the vulcanized rubber composition. .

Furthermore, in the present invention, the rubber component does not necessarily have to be ethylene-propylene rubber alone; it may be used as a main component, and other natural rubbers and various synthetic rubbers may be mixed as needed.

The present invention will be described in detail below based on Examples, but the present invention is not limited thereto.

Example 1 Based on the formulation shown in Table 1, ethylene-propylene rubber and various compounding agents were kneaded using oven rolls. The obtained unvulcanized rubber compositions were vulcanized using a steam press at 170°C for M1 to 12 and 150°C for A18 for 10 minutes to obtain vulcanized rubber sheets each having a length of 2 m.

This sheet was heated to 68℃ with a sunshine weather meter for 1
A weather resistance test was conducted by exposing the sheet to a rainfall cycle of 1 s in 20 minutes for 400 hours, 700 hours, and 1000 hours. The occurrence of cracks in the folded portion when unfolded after being folded in half was evaluated according to the criteria shown in the table below. The results are shown in Table 2.

*l Ethylene-propylene-dicyclopentadiene copolymer rubber manufactured by Sumitomo Chemical *2 Ethylene cyclopyrene ψ ethylidene norbornene copolymer rubber *8 Hydrous silica manufactured by Nippon Silica *4 Anhydrous silica manufactured by Degussa *5 R,
T, Vanderfilt fine powder aluminum silicate *6 Cyprus Ind, Minerals
Fine powder magnesium silicate *7 manufactured by Idemitsu Kosan Co., Ltd. Paraffin-based process oil *8 Dicumyl peroxide *1O manufactured by Nihon Yushi Co., Ltd. G-color pigment represented by the following structural formula *11 Red pigment represented by the following structural formula *12 Japan Manufactured by Ciba Kaigy Co., Ltd. Bis(2,2,6,6-tetramethyl-4-piperidine) sepatate *I3 Compound represented by the following structure *14 Nippon Chirugai manufactured by Iggy Co., Ltd. n,n bis IJ
-(8,5-di-t-butyl-4-hydroxyphenyl)propionyl]hydrazine *15 Pentaerythryl-tetrakis(8-(3,5-di-t-butyl-4-hydroxyphenyl)propionate) *16 2-hydroxy-
4-Octoxybenzophenone *17 & 2-(2-hydroxy-5-t-butyl-5-
methylphenyl)-5-chloropenzotriazole

Claims (1)

[Claims] 5 to 1 hydrated silicic acid and/or anhydrous silicic acid per 100 parts by weight of ethylene-propylene rubber.
00 parts by weight, 0.01 to 3 parts by weight of at least one compound selected from the following general formulas (I) and (II), and a compound selected from the following general formulas (III) and (IV). An ethylene-propylene-based vulcanized rubber composition having excellent weather resistance, obtained by peroxide vulcanization of an unvulcanized rubber composition containing 0 to 3 parts by weight of at least one type. General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 represents an alkyl group of C_1_-_3.)General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼( II) (wherein, R_2 is an alkyl group of C_6_ to_1_0, R
_3 represents an alkyl group of C_1_ to _3, and n represents a real number of 1 to 5. ) General formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) (In the formula, R_4 represents an alkyl group of C_1_-_9.) General formula (IV) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IV) (In the formula, R_5 represents an alkyl group of C_1_ to_6, and m represents an integer of 1 to 6.)