JPH07119340B2 - Rubber composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a chlorinated polyethylene rubber-based rubber having excellent vulcanization adhesion to brass, which is useful for rubber / metal composite products used in fields requiring heat resistance and oil resistance. More particularly, the present invention relates to a rubber composition suitable for an inner rubber tube, an outer rubber tube of a heat-resistant high-pressure hose having a brass-plated pressure-resistant steel wire layer, and an intermediate rubber used between layers of the pressure-resistant steel wire layer.

[0002]

2. Description of the Related Art Recently, tires, belts, moldings, rolls,
Many rubber products such as hoses come to be used for a long time with oil heated under high temperature and pressure, and deterioration of the rubber product in such a state is always a serious problem. This is because if the rubber product is severely deteriorated, it requires a lot of time and labor for maintenance and replacement, and the deterioration of the rubber product may cause a major accident.

Excellent oil resistance and at such high temperature (12
As a polymer that can withstand continuous use in an environment of 0 to 150 ° C., an acrylonitrile-butadiene copolymer rubber (N
BR), acrylic rubber (ACM), ethylene-acrylic rubber (AEM), ethylene-acrylic-vinyl acetate copolymer rubber (ER), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM), and acrylonitrile- A rubber in which a conjugated diene portion of an acrylonitrile-based copolymer rubber such as a butadiene copolymer rubber (NBR) is hydrogenated is known. Among these polymers, chlorinated polyethylene rubber is a rubber having an excellent balance of various properties such as heat aging resistance, weather resistance, oil resistance and chemical resistance.

By the way, since chlorinated polyethylene rubber does not contain a double bond in its main chain, it cannot be vulcanized by ordinary sulfur, and generally organic peroxides, thioureas, diamines and trithiocyanuric acid are used. A system vulcanizing agent is used.

However, vulcanized products of thioureas and diamines generally have a low modulus, and vulcanized products of organic peroxides and trithiocyanuric acid have a modulus, but are vulcanized with metals such as brass. Due to poor vulcanization adhesiveness, in industrially using the chlorinated polyethylene rubber composition,
Its use range was extremely limited.

Therefore, the applicant has a high modulus,
And, as a chlorinated polyethylene-based rubber composition having excellent vulcanization adhesion to metals such as brass, chlorinated polyethylene rubber, magnesia, epoxy resin, triallyl isocyanurate, diallyl phthalate, trithiocyanuric acid and organic peroxides. A rubber composition containing a vulcanization system containing as an essential component has been proposed (Japanese Patent Publication No. 61-26820). However, this rubber composition has six types of essential components as a vulcanization system, and therefore has a low degree of freedom in formulating a compounding formulation, and various characteristics are improved as compared with conventional ones. However, it was not completely satisfactory.

[0007]

As described above, a chlorinated polyethylene rubber composition having a high vulcanizate modulus and excellent vulcanization adhesion to a metal such as brass,
Moreover, there is no known compound having a high degree of freedom in formulation.

The present invention has been made in view of the above facts, and can easily express a high modulus, has excellent vulcanization adhesion to a metal such as brass, and has a relatively simple formulation. An object of the present invention is to provide a chlorinated polyethylene-based rubber composition.

[0009]

According to the present invention, 100 parts by weight of a chlorinated polyethylene rubber (A) and / or a maleic anhydride-modified chlorinated polyethylene rubber (B) is used in an amount of 2,
Dicyclohexylamine salt of 4,6-trimercapto-1,3,5-triazine (abbreviation: TDCA) (C) 0.
A rubber composition containing 2 to 10 parts by weight is provided.

In addition to the rubber composition, 5 parts by weight or less of 2-mercaptobenzothiazole is added to 100 parts by weight of the chlorinated polyethylene rubber (A) and / or the maleic anhydride-modified chlorinated polyethylene rubber (B). Dicyclohexylamine salt (abbreviation: MDCA) (D), or the chlorinated polyethylene rubber (A) and / or maleic anhydride-modified chlorinated polyethylene rubber (B) 10
It is preferable to add 5 parts by weight or less of sulfur (E) and / or organic sulfur-containing compound (F) other than TDCA (C) and MDCA (D) to 0 part by weight.

Alternatively, 10 parts by weight or less of MDCA (D) is added to 100 parts by weight of the chlorinated polyethylene rubber (A) and / or maleic anhydride-modified chlorinated polyethylene rubber (B) in the rubber composition. And 5 parts by weight or less of sulfur (E) and / or TDCA (C), MD
It is preferable to contain an organic sulfur-containing compound (F) other than CA (D).

The present invention will be described in detail below. The polymer of the rubber composition of the present invention is chlorinated polyethylene rubber (A) and / or maleic anhydride-modified chlorinated polyethylene rubber (B).

As the chlorinated polyethylene rubber (A),
Various grades having different molecular weight, chlorine content, distribution of bound chlorine, etc. are known. In the present invention, any grade of chlorinated polyethylene rubber may be used.

The maleic anhydride-modified chlorinated polyethylene rubber (B) is obtained by reacting the chlorinated polyethylene rubber (A) with maleic anhydride during kneading so that the chlorinated polyethylene rubber and maleic anhydride are mixed with each other. It is polymerized.

When the maleic anhydride-modified chlorinated polyethylene rubber (B) is used, the cross-linking efficiency is increased by the effect of the group consisting of dicarboxylic acid and / or its anhydride, and therefore, the degree of freedom in formulating the formulation is increased. Improved and preferable.

Commercially available products corresponding to the maleic anhydride-modified chlorinated polyethylene rubber (B) include Eraslen Super (Showa Denko KK).

In the present invention, either one of the chlorinated polyethylene rubber (A) and the maleic anhydride-modified chlorinated polyethylene rubber (B) may be used, or both may be used together.

The main components of the rubber composition of the present invention are the chlorinated polyethylene rubber (A) and / or the maleic anhydride-modified chlorinated polyethylene rubber (B), depending on the type of vulcanizing agent. It can be divided into four types.

First, as a vulcanizing agent, 2,4,6-trimercapto-1,3,5- which is an organic sulfur-containing compound.
Dicyclohexylamine salt of triazine (abbreviation: TDC)
A) is the chlorinated polyethylene rubber (A) and / or maleic anhydride-modified chlorinated polyethylene rubber (B)
The rubber composition contains 0.2 to 10 parts by weight with respect to 100 parts by weight.

Secondly, the above-mentioned TDCA is used as a vulcanizing agent.
(C) is contained in the above amount, and a dicyclohexylamine salt of 2-mercaptobenzothiazole (abbreviation: MDCA) (D), which is also an organic sulfur-containing compound, is added to the chlorinated polyethylene rubber (A) and / or maleic acid. A rubber composition containing 5 parts by weight or less (not including 0 parts by weight) per 100 parts by weight of the modified chlorinated polyethylene rubber (B).

Thirdly, the TDCA is used as a vulcanizing agent.
(C) is contained in the above amount, and further, sulfur (E) and / or organic sulfur-containing compound (F) other than TDCA (C) and MDCA (D) is added to the chlorinated polyethylene rubber (A) and / or anhydrous. A rubber composition containing 5 parts by weight or less (not including 0 parts by weight) per 100 parts by weight of maleic acid-modified chlorinated polyethylene rubber (B).

Fourthly, the above-mentioned TDCA is used as a vulcanizing agent.
(C), the MDCA (D), and the sulfur (E)
And / or organic sulfur-containing compound (F) other than TDCA (C) and MDCA (D), relative to 100 parts by weight of the chlorinated polyethylene rubber (A) and / or maleic anhydride-modified chlorinated polyethylene rubber (B). Each,
The rubber composition contains 0.2 to 10 parts by weight, 10 parts by weight or less (not including 0 parts by weight), and 5 parts by weight or less (not including 0 parts by weight).

2,4,6-Trimercapto-1,3,5 used as a vulcanizing agent in the rubber composition of the present invention
-The dicyclohexylamine salt of triazine (C) is T
It is a compound abbreviated as DCA and represented by the following formula I.

[0024]

[Chemical 1]

The present inventors have heretofore referred to this TDCA compound by covalently bonding a carbon atom having no mercapto group of a triazine ring and a nitrogen atom of a dicyclohexylamino group, as shown in the following formula II. Compound (6-dicyclohexylamino-2,4-dimercapto-1,
3,5-triazine). However, in the subsequent research, the triazine ring had three mercapto groups, and the sulfur atom constituting one of the mercapto groups was ionically bonded to the nitrogen atom of dicyclohexylamine to form a salt. Of the compound (dicyclohexylamine salt of 2,4,6-trimercapto-1,3,5-triazine represented by the above formula I).

[0026]

[Chemical 2]

The dicyclohexylamine salt of 2-mercaptobenzothiazole (D), which is also used as a vulcanizing agent in the rubber composition of the present invention, is a compound abbreviated as MDCA and represented by the following formula III.

[0028]

[Chemical 3]

The present inventors initially considered this compound to be N, N-dicyclohexyl-benzothiazylsulfenamide represented by the following formula IV in which a sulfur atom and a nitrogen atom were covalently bonded. However, after that,
It was revealed that the compound was a compound in which a sulfur atom and a nitrogen atom formed a salt by an ionic bond.

[0030]

[Chemical 4]

As the sulfur (E), sulfur that is generally used as a vulcanizing agent for rubber, such as powdered sulfur, highly dispersible sulfur and insoluble sulfur, is used, and sulfur is particularly preferable.

In the present invention, the organic sulfur-containing compound (F)
Is an organic sulfur-containing compound (F) other than the TDCA (C) and the MDCA (D), that is, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram. Thiurams such as tetrasulfide, pentamethylenedithiocarbamic acid piperidine salt, pipecolyl dithiocarbamic acid pipecoline salt, dimethyldithiocarbamate zinc,
Zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, zinc N-pentamethylenedithiocarbamate, zinc dibenzyldithiocarbamate, sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate, Dithiocarbamates such as copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, tellurium diethyldithiocarbamate, etc., xanthates such as zinc butylxanthate, zinc isopropylxanthate, sodium isopropylxanthate, N-
Cyclohexyl-2-benzothiazole sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, N-oxydiethylene-2-benzothiazole sulfenamide, N, N-diisopropyl-2-benzothiazole sulfenamide And the like, and thiazoles such as 2-mercaptobenzothiazole and dibenzothiazyl disulfide.

Since each of the rubber compositions of the present invention contains TDCA (C) as a vulcanizing agent, it has both physical properties of vulcanized rubber and vulcanization adhesiveness to metals such as brass. Excel. However, like the second to fourth rubber compositions, when MDCA (D) and sulfur (E) and / or organic sulfur-containing compound (F) are further contained, MDCA (D) and sulfur (E) are contained. And / or the organic sulfur-containing compound (F) is TD
Since it has a synergistic effect with CA (C), it becomes a rubber composition having further excellent vulcanized rubber physical properties and vulcanized adhesiveness to metals such as brass. In addition, MDCA (D) and sulfur (E) as vulcanizing agents
A rubber composition containing an organic sulfur-containing compound (F) and / or a vulcanizing agent in a smaller amount can be a rubber composition exhibiting desired vulcanized rubber physical properties and vulcanization adhesiveness with metal. Therefore, the degree of freedom in formulating a combination prescription is increased.

The vulcanizing agent contained in the rubber composition of the present invention is as described above, and the content ratio thereof is as follows.

TDCA (C) is contained in any of the first to fourth rubber compositions, and the content ratio thereof is the above chlorinated polyethylene rubber (A) and / or maleic anhydride-modified chlorinated polyethylene rubber ( B) 0.2 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight. If it is less than 0.2 parts by weight, the vulcanization will not be sufficiently carried out, while if it is more than 10 parts by weight, the heat resistance of the vulcanized rubber will decrease, which is not preferable.

MDCA (D) is contained in the second and fourth rubber compositions, and the content ratio of MDCA (D) in the second case is
It is 5 parts by weight or less (not including 0 parts by weight) based on 100 parts by weight of the chlorinated polyethylene rubber (A) and / or the maleic anhydride-modified chlorinated polyethylene rubber (B). If it exceeds 5 parts by weight, the vulcanization adhesion to metal such as brass will be insufficient. In the fourth case, the amount is 10 parts by weight or less (not including 0 parts by weight) with respect to 100 parts by weight of the chlorinated polyethylene rubber (A) and / or the maleic anhydride-modified chlorinated polyethylene rubber (B). If it is more than 10 parts by weight,
Lack of vulcanization adhesion to metals such as brass.

Sulfur (E) and / or organic sulfur-containing compound (F) is contained in the third and fourth rubber compositions, and the content ratio thereof is the chlorinated polyethylene rubber (A) and / or anhydrous. It is 5 parts by weight or less (not including 0 parts by weight) with respect to 100 parts by weight of the maleic acid-modified chlorinated polyethylene rubber (B). If it exceeds 5 parts by weight, the heat resistance of the vulcanized rubber is lowered, which is not preferable.

As the sulfur (E) and the organic sulfur-containing compound (F), one kind of compound may be used, or two or more kinds of compounds may be appropriately used in combination.

The above is the essential components of the rubber composition of the present invention and their content ratios. If necessary, an acid acceptor such as magnesia, a filler, and a reinforcing agent which are usually used in this rubber composition. , Plasticizers, antiaging agents, processing aids and the like may be compounded and kneaded.

The rubber composition of the present invention is used for tires, belts,
It can be applied to many rubber products such as molds, rolls and hoses, which are used for a long time under high temperature and high pressure environment and require oil resistance.

The rubber composition of the present invention has excellent adhesiveness to brass and is therefore useful in a field where it is vulcanized and integrated with a brass body to be a product.

Here, the brass body is used as a reinforcing material for ordinary rubber products, and means a wire material, a pipe material, a plate material, a steel material or the like, and may be brass-plated.

In particular, the rubber composition of the present invention is suitable for an inner rubber, an outer rubber of a heat-resistant high-pressure hose having a pressure-resistant steel wire layer plated with brass, and an intermediate rubber used between layers of the pressure-resistant steel wire layer. Is.

The vulcanization method may be a commonly used method,
It may be vulcanized by a method such as press vulcanization, steam vulcanization, and hot water vulcanization at a temperature of about 130 to 200 ° C.

[0045]

EXAMPLES The present invention will be specifically described below based on examples. First, the method of the performance evaluation test performed here will be described.

1. 1. Measurement of elastic modulus (100% modulus) A rubber composition is prepared and mixed with a mixing roll at 60 ° C for 15 minutes, and then with a small lab roll.
Sheets were taken out to a thickness of 0 mm. This sheet-shaped rubber was pressure-vulcanized at a surface pressure of 30 kgf / cm ² at 165 ° C. for 30 minutes with a lab press molding machine. This is JIS K6
Using a tensile tester specified in No. 301, pulling speed 500
100% modulus was measured and calculated by pulling at mm / min. All measurement methods and calculations are in accordance with JIS K6.
301 3. It was conducted according to the method described in the tensile test. Regarding the physical properties of the vulcanized rubber, the stress is preferably 50 kgf / cm ² or more when expressed by 100% modulus, and 70 kgf / cm ² or more depending on the application.

2. 1. Vulcanization adhesion test with brass Prepare a rubber composition and mix it with a mixing roll at 60 ° C for 15 minutes, and then with a small lab roll.
The sheet was taken out to a thickness of 5 mm. Then, as shown in FIG. 1, a rubber sheet 1 having a thickness of 2.5 mm was pressed onto a brass plate 2. However, the cellophane paper 3 was placed on the portion to be gripped by the chuck during peeling so that the upper and lower layers were not adhered. This is 3 at 165 ℃ with a lab press molding machine.
It was pressure-vulcanized at a surface pressure of 30 kgf / cm ² for 0 minutes, and was integrally molded. After standing at room temperature for 24 hours, the integrally molded sample was cut out into a width of 2.54 cm and subjected to an adhesion test. The peeling force was measured in accordance with the method described in JIS K6301 8.3, which peels rubber adhered to a metal piece in the direction of 90 degrees, using a tensile tester specified in JIS K6301 and a pulling speed of 50 mm. / min. Vulcanization adhesion with brass has a peeling force of 7kgf / 25mm or more, depending on the application it is 1
It is preferably 0 kgf / 25 mm or more.

(Example 1) Compounding effect of TDCA Using the rubber compositions shown in Table A, the performance evaluation test was conducted. The results are shown in Table A. As is clear from Table A, when the conventional vulcanizing agent was used (Comparative Examples 1 and 2), both the stress of the vulcanized rubber and the vulcanization adhesiveness with brass could not be satisfied. , TDCA is used as a vulcanizing agent (Examples 1 to 1
By 3), both can be satisfied.

Table A * 1 Showa Denko Co., Ltd. Maleic anhydride modified chlorinated polyethylene rubber * 2 Sankyo Kasei Co., Ltd. trithiocyanuric acid * 3 Asahi Carbon Co., Ltd. SRF grade carbon black * 4 Adeka Argus Chemical Co., Ltd. trimellitic acid ester

Example 2 Content of TDCA Using the rubber compositions shown in Table B, the performance evaluation test was conducted. The results are shown in Table B. As is clear from Table B,
If the TDCA content is less than 0.2 parts by weight (Comparative Examples 3 and 4), the stress of the vulcanized rubber is insufficient, while if it exceeds 10 parts by weight (Comparative Example 5), the vulcanization adhesion with brass is insufficient. To do.

[0051]

[Table 1]

Example 3 With respect to the effects of sulfur and an organic sulfur-containing compound, the performance evaluation test was conducted using the rubber compositions shown in Table C. The results are shown in Table C. As is clear from Table C, regarding the elastic modulus of the vulcanized rubber and the vulcanization adhesiveness with brass, regardless of the types of sulfur and organic sulfur-containing compounds,
All were at the same level.

[0053]

[Table 2]

[0054]

According to the present invention, there is provided a chlorinated polyethylene rubber composition having a relatively simple blending system, which is excellent in vulcanization adhesion to a metal such as brass and vulcanized rubber physical properties, particularly modulus. Therefore, by applying the chlorinated polyethylene rubber-based rubber composition of the present invention to the rubber portion of various products composed of metal / rubber composites such as tires, belts, molds, rolls, hoses, etc. Products with more excellent physical properties and durability will be provided.

[Brief description of drawings]

FIG. 1 is a front view showing a sample for vulcanization adhesion test of rubber and brass.

[Explanation of symbols]

 1 rubber 2 brass plate 3 cellophane paper

Claims (4)

[Claims] 1. A chlorinated polyethylene rubber (A) and / or
Or, with respect to 100 parts by weight of maleic anhydride-modified chlorinated polyethylene rubber (B), dicyclohexylamine salt of 2,4,6-trimercapto-1,3,5-triazine (abbreviation: TDCA) (C) 0.2- A rubber composition containing 10 parts by weight. 2. Further, 5 parts by weight or less of a dicyclohexylamine salt of 2-mercaptobenzothiazole (100 parts by weight of the chlorinated polyethylene rubber (A) and / or maleic anhydride-modified chlorinated polyethylene rubber (B) ( The rubber composition according to claim 1, containing an abbreviation: MDCA) (D). 3. Further, 5 parts by weight or less of sulfur (E) and / or TDCA (C) is added to 100 parts by weight of the chlorinated polyethylene rubber (A) and / or the maleic anhydride-modified chlorinated polyethylene rubber (B). ), MDCA
The rubber composition according to claim 1, which contains an organic sulfur-containing compound (F) other than (D). 4. Further, 10 parts by weight or less of MDCA (D) is contained with respect to 100 parts by weight of the chlorinated polyethylene rubber (A) and / or the maleic anhydride-modified chlorinated polyethylene rubber (B). The rubber composition according to.