JPS6234954A - Vulcanizable epichlorohydrin rubber composition - Google Patents

Abstract

PURPOSE:The titled composition having improved thermal aging resistance and processing properties, obtained by blending epichlorohydrin rubber with a specific amount of a specific liquid modified ethylene.alpha-olefin copolymer. CONSTITUTION:(A) Epichlorohydrin rubber is blended with (B) a liquid modified ethylene.alpha-olefin copolymer which is obtained by subjecting 100pts.wt. ethylene.alpha-olefin copolymer and 0.2-5pts.wt. one or more unsaturated carboxylic acid compounds to graft copolymerization and has 0.01-0.3dl/g intrinsic viscosity [eta], in a weight ratio of the component A/B=98/2-50/50, preferably 90/10-70/30.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to vulcanizable epichlorohydrin rubber compositions, and more particularly to vulcanizable epichlorohydrin rubber compositions with improved heat aging resistance and processability.

BACKGROUND OF THE INVENTION Epichlorohydrin rubber has excellent properties such as oil resistance, ozone resistance, cold resistance, and heat resistance, and is used in various fields such as sealing materials for cylinders, O-rings, and automobile fuel hoses.

However, although this epichlorohydrin rubber has these excellent properties, it has the disadvantage that heat resistance is significantly impaired when a plasticizer is used in combination to improve its processability.

Summary of the Invention As a result of extensive studies, the present inventors have discovered that when blending a specific liquid modified ethylene/α-olefin copolymer with epichlorohydrin rubber, it is possible to improve the heat resistance and other excellent properties of epichlorohydrin rubber. It has been found that the processability can be significantly improved without any loss.

An object of the present invention is to provide a vulcanizable epichlorohydrin rubber composition that has excellent combinations of properties such as heat resistance, oil resistance, ozone resistance, and cold resistance, and moldability.

Structure of the Invention According to the present invention, the shrimp chlorhydrinococonil has an intrinsic viscosity [η) (135°C, decalin) of 0.01 to 0.
3. Mainly composed of liquid modified ethylene/α-olefin copolymer (2) in the range of 3 dt/El.

The liquid modified ethylene/α-olefin copolymer (2)
is an ethylene/α-olefin copolymer obtained by graft copolymerizing at least one compound selected from unsaturated carboxylic acid compounds, and epichlorohydrin rubber (
6) and liquid modified ethylene/α-olefin copolymer (2
) means A/B=98/2 to 5015 on a weight basis
There is provided a vulcanizable epichlorohydrin rubber composition comprising:

The epichlorohydrin rubber used in the present invention is
A synthetic rubber consisting of an epichlorohydrin homopolymer, a copolymer of epichlorohydrin and ethylene oxide, or a copolymer of these polymers or copolymers and allyl glycidyl ether, and has a chlorine content of 20 to 40% by weight. % and Mooney viscosity ML, +4 (100°C) are in the range of 20 to 150.

Although this epichlorohydrin rubber has excellent properties such as oil resistance, ozone resistance, heat resistance, and cold resistance, its heat resistance is particularly impaired when a plasticizer is used together to improve processability. The problem is that

To this end, in the present invention, by combining the liquid modified ethylene/α-olefin copolymer described below, it is possible to improve not only the heat resistance but also the moldability of epichlorohydrin rubber without impairing its other properties. It was a success.

In the present invention, the liquid modified copolymer used in combination with the epichlorohydrin rubber (A) has an intrinsic viscosity [η] (135°C
, measured with decahydronaphthalene solution) is 0.01 to 0.
．． 3 di/El, preferably 0.03 to 0.25 t
It is important that it is in the range of zt/i. When the intrinsic viscosity is smaller than the above range, the desired heat aging resistance cannot be obtained, and when it is larger, the processability is impaired.

Further, this liquid modified copolymer is a modified ethylene/α-olefin copolymer that has been digraft modified by grafting an unsaturated carboxylic acid compound.

The α-olefin constituting such a modified copolymer is usually an α-olefin having 3 to 20 carbon atoms, such as ethyl pyrene, 1-butene, 1-pentene, 1-hexene, 4
-Methyl-1--27tene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, -hexadecene, 1-octadecene, 1-eicosene, etc. are used.

In addition, the ethylene and α-olefin constituting this modified copolymer are contained in the copolymer on a molar basis from '30/70 to 7.
It is preferably contained in a ratio of 5/25, particularly 40/60 to 70/30.

The unsaturated carboxylic acid compound used as a modifier is one or more selected from the group consisting of unsaturated carboxylic acids containing 3 to 10 carbon atoms, their acid anhydrides, their amides, their imides, and their esters. For example, acrylic acid, 6-(meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, norporene dicarboxylic acid, tetrahydrophthalic acid, bicyclo[2°2.1]heguto3
-Unsaturated carboxylic acids such as ene-5,6-dicarboxylic acid,
maleic anhydride, itaconic anhydride, citraconic anhydride,
Tetrahydrophthalic anhydride, bicyclo[2,2,1)
(7') unsaturated carboxylic acid anhydrides such as -2-ene-5,6-dicarginic anhydride; amides or imides such as maleic acid monoamide, maleic acid diamide, maleimide;
Methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl maleate,
Diethyl 7marate, dimethyl itaconate, diethyl cytodiconate, dimethyl tetrahydrophthalic anhydride, dimethyl bicyclo(2,2゜1)hept-2-ene-5,6-dicarboxylate, glycidyl (meth)acrylate, etc. Examples include unsaturated carboxylic acid esters.

Among these, preferred are maleic anhydride, maleic monoamide, maleic diamide, maleimide, monomethyl maleate, diethyl maleate, glycidyl (meth)acrylate, and the like.

The grafting ratio of the graft copolymer component is 0.2 parts by weight per 100 parts by weight of the ethylene/α-olefin copolymer.
A range of from 0.5 to 30 parts by weight is preferred, particularly from 0.5 to 30 parts by weight. If the grafting ratio is too small, the resulting liquid modified copolymer will not be compatible with the epichlorohydrin rubber and will bleed out onto the surface of the composition, and if the grafting ratio is too large, the resulting rubber composition will be unsatisfactory in cold resistance. Become something.

The liquid modified copolymer described above is easily produced by reacting a liquid ethylene/α-olefin copolymer with one or more of the above unsaturated carboxylic acid compounds, for example, in the presence of a radical initiator. be able to.

The reaction can be carried out in the presence of a solvent or in the absence of a solvent. As for the reaction method,
For example, a method may be exemplified in which the unsaturated urgonic acid compound and a radical initiator are continuously or intermittently supplied to a heated liquid ethylene/α-olefin copolymer under stirring to cause a reaction. . The proportion of the unsaturated carboxylic acid compound supplied to the graft reaction is usually 0.2 to 50 parts by weight, preferably 0.5 to 30 parts by weight, per 100Ji parts of the liquid ethylene α-olefin copolymer. The proportion of the radical initiator is usually 0.04 to 15 parts by weight, preferably 0.
．． It ranges from 1 to 10 parts by weight. The temperature during the reaction is usually in the range of 120 to 200°C, preferably 130 to 180°C, and the time required for the reaction is usually 3.
The time period is from 0 minutes to 60 hours, preferably from 10 minutes to 50 hours.

Organic peroxides are usually used as radical initiators for the grafting reaction, and those whose decomposition temperature is in the range of 150 to 270°C at which their half-life is 1 minute are particularly preferred. , organic peresters such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl ester, di-tart
-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate) hexyne-3, 5-dimethyl-2,5-di(tert-
butylperoxy)hexyne-3,2,5-dimethyl-
2,5-di(tert-butylperoxy)hexane,
Mention may be made of tert-butyl perbenzoate, tert-bunalber phenyl acetate, tert-butyl perisobutyrate, tert-butyl perusea-octoate, tert-butyl pervivalate, cumyl pervivalate and tert-butyl perdiethyl acetate. .

The rubber composition of the present invention comprises the above-mentioned epichlorohydrin rubber (A) and liquid modified ethylene/α-olefin copolymer (2), A/B=98/2 to 50150 on a weight basis, preferably 90/10. Blend at a ratio of 70/30.

If the amount of the liquid modified ethylene/α-olefin copolymer (2) is less than the above range, it will be difficult to achieve the objective of improving the processability of the rubber composition, and if it is too much. However, since it reduces the strength of the rubber composition, it becomes difficult to put it into practical use.

In addition, in the composition of the present invention, depending on its use etc.,
Compounds known per se, such as SRF, GPF, FE
F, HAF, TSAF, SAF, FT, M
Rubber reinforcing agents such as Carpin 7" rack such as T and finely powdered silicic acid, fillers such as light calcium carbonate, heavy calcium carbonate, Merck, clay, softeners, vulcanizing agents, vulcanization accelerators or vulcanization aids. etc. can be blended.

These compounding agents usually contain a total amount of epichlorohydrin rubber (A) and liquid modified ethylene/α-olefin copolymer (2) in the final composition of 30% by weight or more, preferably 40% by weight or more. It should be used within a certain range.

Within this range, epichlorohydrin rubber (6
) and liquid modified ethylene/α-olefin copolymer (2)
For a total of 100 parts by weight, rubber reinforcing agents and fillers usually contain up to 200 parts by weight, preferably up to 150 parts by weight, and softeners usually contain up to 70 parts by weight, preferably up to 40 parts by weight.
Used in parts by weight.

The vulcanizing agents used are 1) thioureas, 2) polyvalent amines, 3) alkali metal salts, 4) lead cyanate/polyol, 5) thiuram polysulfide, and 6) triazine derivatives, which are commonly used for epichlorohydrin rubber. obtain. The amount of these vulcanizing agents used is epichlorohydrin rubber (A).
The amount is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the total amount of the liquid modified ethylene/α-olefin copolymer (2).

Furthermore, it is well known that lead compounds, magnesia, calcium carbonate, etc. are added as acid acceptors.

Further, by using an anti-aging agent, it is possible to extend the material life of the vulcanizate obtained from the composition of the present invention, as in the case of ordinary rubber. Antioxidants used in this case include, for example, aromatic secondary amines such as phenylnaphthylamine, N,N'-di-2-7-p-phenylenediamine, dibutylhydroxytoluene, tetrakis[methylene(3, Sterically hindered phenolic stabilizers such as 5-di-t-butyl-4-hydroxy)hydrocinnamate comethane are used.

The amount of such anti-aging agent used is usually 0.1 to 5 parts by weight per 100 parts by weight of the total amount of epichlorohydrin rubber (2) and liquid modified ethylene/α-olefin copolymer (2).
The proportion is selected to be 0.5 to 3 parts by weight, preferably 0.5 to 3 parts by weight.

Unvulcanized compounded rubber is usually prepared by the following method.

That is, after kneading epichlorohydrin rubber, liquid ethylene-α-olefin copolymer filler and softening agent 1 into a medium such as pant 4 reamer for 3 to 10 minutes at a temperature of 80°C to 150°C, the mixture is opened. Using rolls such as a roll, the vulcanizing agent is further mixed and kneaded for 5 to 30 minutes at a roll temperature of 40 to 80°C, and then separated and prepared into a liquid or sheet form. .

Vulcanization The compounded rubber thus prepared is molded into the desired shape using an extruder, calender roll, press, etc., and at the same time as the molding or the molded product is introduced into a vulcanization tank, usually 1
A vulcanizate can be obtained by heating at a temperature of 30 to 230°C for usually 1 to 30 minutes.

This vulcanization step may be performed using a mold or without a mold.

The vulcanized products produced in the above manner can be used, for example, in automobile parts such as fuel hoses, emission control hoses, and diaphragms, oil-resistant hoses, hoses for liquid or gaseous full-hollow carbon, and diaphragms for city gas or LPG. Suitable for use in industrial parts, vehicle connecting tops, coating fabrics for firefighting suits, special electric wires, printing rolls, blankets, etc.

The invention will be illustrated by the following example.

Reference Example 1 Into a 21-piece glass reactor equipped with a stirrer and equipped with a nitrogen blowing tube, a water-cooled condenser, a thermometer, and two dropping funnels, ethylene composition was 50 molar and number average molecular weight was 810. (η)
0.04dl111. Kinematic viscosity at 100℃: 22
．． 8 eat ethylene propylene copolymer 5ooI
I'l was added, and nitrogen substitution was performed for 2 hours to expel dissolved oxygen. Thereafter, the internal temperature of the flask was raised to 160°C, and maleic anhydride 40Ii (heated to 60°C and kept in a liquid state), which had been charged in advance to each of the two dropping funnels, and di-tertiary - Butyl peroxide 8I is added dropwise over 4 hours. After completing the dropwise reaction, the reaction was carried out for 4 hours, and then the temperature inside the flask was raised to 180°C.
Unreacted maleic anhydride and di-
Decomposition products of tertiary glutyl peroxide are removed.

The modified ethylene-propylene copolymer product is (η)
0.04 dl/1/, 100℃Niokel kinematic viscosity 33
．． It was a yellow transparent liquid with a weight of 8 oat, and the grafting ratio of the oleic anhydride component was 4.51 parts by weight per 100 parts by weight of the ethylene propylene copolymer.

Reference example 2 Ethylene composition 49 mol%, kinematic viscosity at 100°C 14
5est, number average molecular weight 1500, [η] 0,05 d
t/11 ethylene-propylene copolymer 595I
The mixture was charged into a glass reactor No. 1, and the temperature was raised to 140°C. Then, 105 g of n-butyl methacrylate and
9.0 g of art-butyl peroxide was added thereto, and the mixture was heated and reacted for 4 hours. Next, while keeping the temperature at 140℃,
After removing volatile components by degassing under a vacuum of 0 mHH for 1 hour, a liquid modified ethylene random copolymer was obtained by cooling. The liquid modified ethylene random copolymer has a number average molecular weight of 1500 and [η) 0.06 dt.
/F/.

Kinematic viscosity at 100°C 200 ast, n −1
The grafting ratio of tyl methacrylate was 16 parts by weight (the content of n-butyl methacrylate component was 14 parts by weight) based on 100 parts by weight of the ethylene/nolopyrene copolymer, and the resulting product was a colorless and transparent liquid.

Example 1 The liquid modified ethylene/α-olefin copolymer synthesized in Reference Example 1 was kneaded for 20 minutes using an 8-inch roll mill with a surface temperature of 40±5° C. at the following blending ratio. At that time, the windability around the roll was visually judged.

Zeku oil 1001) 90.0 parts by weight liquid modified ethylene/α-olefin copolymer 10
．． 0 11 Stearic acid 1.
0〃FEF・Car $72) 7
r), 0.

Red lead 7. OON Suncellar 2: l”C1,20p Tsukrac 224 1.50 N) Epic tetrahydrin: Nippon Zeon Co., Ltd. 2) Asahi 60: Asahi Carbon Co., Ltd. 3) 2-Mercazotoimidazoline: Sanshin Kagaku Co., Ltd. Made by 4) Powa (2,
2,4-4 rimethyl ν-1,2-dihytoyaquinoline): methane blend was mixed at 160°C for 10 min.
The vulcanized rubber sheet was press-cured for 300 minutes under a pressure of 0 k19/crn to produce a 2-day thick vulcanized rubber sheet.The obtained vulcanized rubber sheet was left in a constant temperature room at 25°C for 1 day and then used for measurement. did.

First, tensile strength, elongation, permanent set spring hardness were measured based on JTB K6301, and heat aging resistance (135℃
The retention rate of the vulcanized physical properties was examined after being left for 70 hours. The results are shown in Table 1.

Example 2 In Example 1, the blending ratio was changed to the following. Others are Example 1
I did exactly the same thing. The results are shown in Table 1.

Zekron 1100 60.0 parts by weight Liquid modified dilucyl-alpha-o44one copolymer 40. Ott
Tin Stearate 2.0IFEF-Carbon 70. Ott lead red
7.0Ott sun cellar 22-
C1,20# TSURAKU 224 1.50 //Comparative Example 1 In Example 1, the liquid modified ethylene/α-olefin copolymer was not blended. The rest was carried out in exactly the same manner as in Example 1.

Comparative Example 2 In Example 1, aromatic process oil *) was used as a base for the liquid modified ethylene α-olefin copolymer. The rest was carried out in exactly the same manner as in Example 1.

*Diana Process Oil AH-16: Comparative Example 3, manufactured by Idemitsu Kosan Co., Ltd. In Example 2, DOP* was used as the base of the liquid modified ethylene/α-olefin copolymer. The rest was carried out in exactly the same manner as in Example 2.

*Dioctylphthalate Comparative Example 4 Except for using the solid modified ethylene/propylene copolymer synthesized in Reference Example 3 in place of the liquid modified ethylene/α-olefin copolymer synthesized in Reference Example 1 in Example 1. The same procedure as in Example 1 was carried out. The results are shown in Table 1.

Example 3 In this example, the liquid ethylene/α-olefin copolymer synthesized in Reference Example 2 was used as a base for the liquid ethylene/α-olefin copolymer synthesized in Reference Example 1. The rest was carried out in exactly the same manner as in Example 1.

Claims (3)

[Claims] (1) Epichlorohydrin rubber (A) and intrinsic viscosity [η
] (measured at 135℃ with decahydronaphthalene solution) is 0
．． and the liquid modified ethylene/α-olefin copolymer (B) in a range of 0.01 to 0.3 dl/g, the liquid modified ethylene/α-olefin copolymer (2)
is an ethylene/α-olefin copolymer obtained by graft copolymerizing at least one type of unsaturated carboxylic acid compound, and the epichlorohydrin rubber (A) and the liquid modified ethylene/α-olefin copolymer (B) are A vulcanizable epichlorohydrin rubber composition, characterized in that it contains A/B in a ratio of 98/2 to 50/50 on a weight basis. (2) The epichlorohydrin according to claim 1, wherein the unsaturated carboxylic acid compound is one or more selected from the group consisting of unsaturated carboxylic acids, their anhydrides, their amides, their imides, and their esters. Rubber composition. (3) The grafting ratio of the unsaturated carboxylic acid compound is in the range of 0.2 to 50 parts by weight based on 100 parts by weight of the ethylene/α-olefin copolymer.
The epichlorohydrin rubber composition described in Section 1.