JPH04227945A - Rubber composition - Google Patents

Abstract

PURPOSE:To develop a chlorinated polyethylene rubber composition which can easily exhibit a high modulus, excels in bondability by vulcanization with a metal such as brass, and has a relatively simple compounding recipe. CONSTITUTION:A rubber composition comprising 100 pts.wt. chlorinated polyethylene rubber and/or maleic anhydride-modified chlorinated polyethylene rubber and 0.2-10 pts.wt. dicyclohexylamine salt of 2,4,6-trimercapto-1,3,5-triazine.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a chlorinated polyethylene rubber-based rubber that has excellent vulcanization adhesion to brass and is useful for rubber/metal composite products used in fields that require heat resistance and oil resistance. The present invention relates to a composition, and particularly to a rubber composition suitable for use as an intermediate rubber between the inner tube rubber, outer tube rubber, and pressure-resistant reinforcing steel wire layer of a heat-resistant high-pressure hose having a brass-plated pressure-resistant reinforcing steel wire layer.

0002

[Prior Art] Recently, tires, belts, molded products, rolls,
Many rubber products, such as hoses, are used for long periods of time with heated oil under high temperature and pressure, and the deterioration of rubber products under such conditions is always a serious problem. This is because if the rubber product deteriorates significantly, a great deal of time and effort is required for maintenance and replacement, and furthermore, the deterioration of the rubber product may cause a major accident.

[0003] It has excellent oil resistance and can withstand such high temperatures (12
Acrylonitrile-butadiene copolymer rubber (N
BR), acrylic rubber (ACM), ethylene-acrylic rubber (AEM), ethylene-acrylic-vinyl acetate copolymer rubber (ER), chlorosulfonated polyethylene rubber (
Rubbers in which the conjugated diene portion of an acrylonitrile copolymer rubber is hydrogenated, such as CSM), chlorinated polyethylene rubber (CM), and acrylonitrile-butadiene copolymer rubber (NBR), are known. Among these polymers, chlorinated polyethylene rubber is a rubber with 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 double bonds in its main chain, it cannot be vulcanized with ordinary sulfur, and is generally vulcanized with organic peroxides, thioureas, diamines, and trithiocyanuric acid. A series of vulcanizing agents are used.

However, in general, vulcanizates made from thioureas and diamines have low modulus, and vulcanizates made from organic peroxides and trithiocyanuric acid have high modulus, but are difficult to vulcanize with metals such as brass. Due to poor sulfur adhesion, chlorinated polyethylene rubber compositions are difficult to use industrially.
Its scope of use was extremely limited.

[0006] Therefore, the present applicant has developed a method that has a high modulus and
In addition, as a chlorinated polyethylene rubber composition that has excellent vulcanization adhesion to metals such as brass, magnesia, epoxy resin, triallyl isocyanurate, diallyl phthalate, trithiocyanuric acid, and organic peroxide are added to chlorinated polyethylene rubber. proposed a rubber composition containing a vulcanization system containing as an essential component (Japanese Patent Publication No. 61-26820). However, since this rubber composition has six types of essential components as a vulcanization system, there is little freedom in formulating the formulation, and the various properties have not been improved compared to the past. However, it was not completely satisfactory.

[0007]

[Problems to be Solved by the Invention] As mentioned above, it is a chlorinated polyethylene rubber composition, which has a high modulus of vulcanizate, and has excellent vulcanization adhesion to metals such as brass.
In addition, there is no known compound with a high degree of freedom in formulation.

The present invention has been made in view of the above-mentioned facts, and it is possible to easily develop a high modulus, has excellent vulcanization adhesion to metals such as brass, and has a relatively simple formulation. The object of the present invention is to provide a chlorinated polyethylene rubber composition.

[0009]

[Means for Solving the Problems] The present invention provides chlorinated polyethylene rubber (A) and/or maleic anhydride modified chlorinated polyethylene rubber (B) of 2.
Dicyclohexylamine salt of 4,6-trimercapto-1,3,5-triazine (abbreviation: TDCA) (C) 0.
The present invention provides a rubber composition characterized in that it contains 2 to 10 parts by weight.

The rubber composition further contains 5 parts by weight or less of 2-mercaptobenzothiazole based on 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 contain sulfur (E) and/or an organic sulfur-containing compound (F) other than TDCA (C) and MDCA (D) in an amount of 5 parts by weight or less per 0 parts by weight.

Alternatively, the rubber composition further contains 10 parts by weight or less of MDCA (D) per 100 parts by weight of the chlorinated polyethylene rubber (A) and/or the maleic anhydride-modified chlorinated polyethylene rubber (B). and up to 5 parts by weight 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 explained 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).

[0013] As the chlorinated polyethylene rubber (A),
Various grades are known that differ in their molecular weight, chlorine content, distribution of combined chlorine, etc. In the present invention, any grade of chlorinated polyethylene rubber may be used.

Maleic anhydride-modified chlorinated polyethylene rubber (B) refers to the chlorinated polyethylene rubber (A) that is reacted with maleic anhydride during kneading to combine the chlorinated polyethylene rubber and maleic anhydride. It is polymerized.

When the maleic anhydride-modified chlorinated polyethylene rubber (B) is used, the crosslinking efficiency is increased due to 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 preferred.

Commercially available products corresponding to the maleic anhydride-modified chlorinated polyethylene rubber (B) include Elastrene 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 in combination.

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), but depending on the type of vulcanizing agent, It can be divided into four types.

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

[0020] The second is the above-mentioned TDCA as a vulcanizing agent.
(C) in the above amount, and 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. This is a rubber composition containing 5 parts by weight or less (not including 0 parts by weight) per 100 parts by weight of modified chlorinated polyethylene rubber (B).

[0021] The third is the above-mentioned TDCA as a vulcanizing agent.
(C) in the above amount, and further contains sulfur (E) and/or an organic sulfur-containing compound (F) other than TDCA (C) or MDCA (D) in the chlorinated polyethylene rubber (A) and/or anhydrous This is 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).

[0022] The fourth is the above-mentioned TDCA as a vulcanizing agent.
(C), the MDCA (D), and the sulfur (E)
and/or an organic sulfur-containing compound (F) other than TDCA (C) or MDCA (D) per 100 parts by weight of the chlorinated polyethylene rubber (A) and/or maleic anhydride-modified chlorinated polyethylene rubber (B). , respectively,
The rubber composition contains 0.2 to 10 parts by weight, 10 parts by weight or less (excluding 0 parts by weight), and 5 parts by weight or less (excluding 0 parts by weight).

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

[0024]

[Chemical formula 1]

The present inventors have conventionally developed a compound abbreviated as TDCA in which a carbon atom having no mercapto group in a triazine ring and a nitrogen atom in a dicyclohexylamino group are covalently bonded, as shown in the following formula II. The compound (6-
dicyclohexylamino-2,4-dimercapto-1,
3,5-triazine). However, subsequent research revealed that the triazine ring has three mercapto groups, and the sulfur atom constituting one of the mercapto groups and the nitrogen atom of dicyclohexylamine form an ionic bond, forming a salt. It has been revealed that the compound is a dicyclohexylamine salt of 2,4,6-trimercapto-1,3,5-triazine represented by the above formula I.

[0026]

[Chemical 2]

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

[0028]

[C3]

The present inventors initially thought that this compound was an N,N-dicyclohexyl-benzothiazylsulfenamide represented by the following formula IV, in which a sulfur atom and a nitrogen atom are covalently bonded. However, subsequent research revealed that it is a compound in which sulfur and nitrogen atoms form a salt through ionic bonding.

[0030]

[C4]

As the sulfur (E), sulfur commonly used as a vulcanizing agent for rubber, such as powdered sulfur, highly dispersed sulfur, and insoluble sulfur, is used, but sulfur is particularly preferred.

In the present invention, the organic sulfur-containing compound (F)
means organic sulfur-containing compounds (F) other than the above TDCA (C) and the above MDCA (D), i.e., tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram Thiurams such as tetrasulfide, piperidine pentamethylene dithiocarbamate, pipecoline pipecolyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc N-ethyl-N-phenyldithiocarbamate, N- Zinc pentamethylene dithiocarbamate, zinc dibenzyldithiocarbamate, sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dibutyldithiocarbamate,
Dithiocarbamates such as copper dimethyldithiocarbamate, ferric dimethyldithiocarbamate, tellurium diethyldithiocarbamate, zinc butylxanthate,
Xanthate salts such as zinc isopropylxanthate and sodium isopropylxanthate, N-cyclohexyl-2-benzothiazolesulfenamide,
Sulfenamides such as N-t-butyl-2-benzothiazolesulfenamide, N-oxydiethylene-2-benzothiazolesulfenamide, N,N-diisopropyl-2-benzothiazolesulfenamide, 2
- Refers to thiazoles such as mercaptobenzothiazole and dibenzothiazyl disulfide.

Since all of the rubber compositions of the present invention contain TDCA (C) as a vulcanizing agent, both the physical properties of vulcanized rubber and the vulcanization adhesion to metals such as brass are improved. Excellent. However, when it further contains MDCA (D), sulfur (E) and/or an organic sulfur-containing compound (F) like the second to fourth rubber compositions, MDCA (D) and sulfur (E) and/or the organic sulfur-containing compound (F) is TD
Since it exhibits a synergistic effect with CA(C), it becomes a rubber composition with even better physical properties of vulcanized rubber and vulcanization adhesion to metals such as brass. In addition, MDCA (D) and sulfur (E) are used as vulcanizing agents.
and/or a rubber composition that also contains an organic sulfur-containing compound (F), the rubber composition can exhibit desired vulcanized rubber physical properties and vulcanization adhesion to metals even if the vulcanizing agent content is smaller. Therefore, there is a greater degree of freedom in formulating combination formulations.

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

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

[0036] MDCA (D) is contained in the second and fourth rubber compositions, and the content ratio is as follows:
The amount is 5 parts by weight or less (excluding 0 parts by weight) per 100 parts by weight of the chlorinated polyethylene rubber (A) and/or maleic anhydride-modified chlorinated polyethylene rubber (B). If it exceeds 5 parts by weight, vulcanization adhesion to metals such as brass will be insufficient. In the fourth case, said chlorinated polyethylene rubber (
A) and/or maleic anhydride modified chlorinated polyethylene rubber (B) 10 parts by weight or less (
(excluding 0 parts by weight). If it exceeds 10 parts by weight, vulcanization adhesion to metals such as brass will be insufficient.

The sulfur (E) and/or the organic sulfur-containing compound (F) are contained in the third and fourth rubber compositions, and the content ratio is the same as that of the chlorinated polyethylene rubber (A).
) and/or 5 parts by weight or less (excluding 0 parts by weight) per 100 parts by weight of maleic anhydride-modified chlorinated polyethylene rubber (B). If it exceeds 5 parts by weight, the heat resistance of the vulcanized rubber decreases, which is not preferable.

Note that sulfur (E) and organic sulfur-containing compound (F
) may use one type of compound, or may use two or more types of compounds in combination as appropriate.

The above are the essential components and their content ratios of the rubber composition of the present invention, but if necessary, commonly used acid acceptors such as magnesia, fillers, and reinforcing agents may be added to this rubber composition. , plasticizers, anti-aging agents, processing aids, and other additives may be mixed and kneaded.

The rubber composition of the present invention can be used for tires, belts,
It can be applied to many rubber products such as molds, rolls, and hoses that are used for long periods in high temperature and high pressure environments and require oil resistance.

Since the rubber composition of the present invention has excellent adhesion to brass, it is useful in the field of products that are vulcanized and integrated with brass bodies.

[0042] Here, the brass body is used as a reinforcing material in ordinary rubber products, and refers to wire rods, pipe materials, plate materials, steel materials, etc., and may be brass-plated.

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

[0044] The vulcanization method may be a commonly used method,
Vulcanization may be performed at a temperature of about 130 to 200° C. by press vulcanization, steam vulcanization, hot water vulcanization, or the like.

[0045]

[Examples] The present invention will be specifically explained below based on Examples. First, we will describe the method of the performance evaluation test conducted here.

1. Measurement of elastic modulus (100% modulus) A rubber composition was prepared, mixed for 15 minutes at 60°C using a mixing roll, and then mixed using a small laboratory roll.
The sheet was produced to a thickness of 0 mm. This sheet-like rubber was pressure-vulcanized at 165° C. for 30 minutes at a surface pressure of 30 kgf/cm 2 using a laboratory press molding machine. This is JIS
Using a tensile tester specified in K6301, it was pulled at a tensile speed of 500 mm/min, and the 100% modulus was measured and calculated. All measurement methods and calculations are in accordance with JIS K6301 3. The tensile test was conducted in accordance with the method described in the section. Among the physical properties of vulcanized rubber, stress is 50 kgf/c when expressed as 100% modulus.
m2 or more, preferably 70 kgf/cm2 or more depending on the application.

2. Test for vulcanization adhesion to brass A rubber composition was prepared and mixed for 15 minutes at 60° C. using a mixing roll, and then formed into a sheet with a thickness of 2.5 mm using a small laboratory roll. As shown in FIG. 1, 2.
A sheet of rubber 1 with a thickness of 5 mm was pressed onto a brass plate 2. However, cellophane paper 3 was placed on the part to be gripped by the chuck during peeling to prevent the upper and lower layers from adhering. This was pressure-vulcanized at 165° C. for 30 minutes at a surface pressure of 30 kgf/cm 2 using a laboratory press molding machine, and was integrally molded. After being left at room temperature for 24 hours, the molded and integrated sample was heated to 2.
It was cut out to a width of 54 cm and subjected to an adhesion test. The peel force was measured in accordance with the method described in JIS K6301 8.3 Test for peeling rubber adhered to a metal piece in a 90 degree direction, using a tensile tester specified in JIS K6301 at a tensile speed of 50 mm. /min. Vulcanized adhesion with brass is peel force 7 kgf/25 mm or more,
Depending on the application, 10 kgf/25 mm or more is preferable.

(Example 1) Effect of blending TDCA Using the rubber composition shown in Table A, the performance evaluation test was conducted. The results are shown in Table A. As is clear from Table A, when conventional vulcanizing agents were used (Comparative Examples 1 and 2), both the stress of the vulcanized rubber and the vulcanization adhesion to brass could not be satisfied. , using TDCA as a vulcanizing agent (Example 1~
3) This makes it possible to satisfy both parties.

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

(Example 2) The performance evaluation test described above was conducted using the rubber compositions shown in Table B with TDCA content. The results are shown in Table B. As is clear from Table B, when 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 when it exceeds 10 parts by weight (Comparative Example 5), the stress Vulcanization adhesion is insufficient.

[0051]

[Table 1]

(Example 3) The performance evaluation test described above was conducted using the rubber composition shown in Table C to examine the effects of sulfur and organic sulfur-containing compounds. The results are shown in Table C. As is clear from Table C, the elastic modulus of vulcanized rubber and vulcanization adhesion to brass are independent of the type of sulfur and organic sulfur-containing compounds.
Both were at almost the same level.

[0053]

[Table 2]

[0054]

The present invention provides a chlorinated polyethylene rubber composition that has excellent vulcanization adhesion to metals such as brass and physical properties of vulcanized rubber, particularly modulus, and has a relatively simple compounding system. Therefore, by applying the chlorinated polyethylene rubber-based rubber composition of the present invention to the rubber parts of various products composed of metal/rubber composites such as tires, belts, molds, rolls, and hoses, the rubber parts can be improved. Products with better physical properties, durability, etc. will be provided.

[Brief explanation of the drawing]

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

[Explanation of symbols]

1 Rubber 2 Brass plate 3 Cellophane paper

Claims (4)

[Claims] Claim 1: Chlorinated polyethylene rubber (A) and/or maleic anhydride modified chlorinated polyethylene rubber (
B) Contains 0.2 to 10 parts by weight of dicyclohexylamine salt of 2,4,6-trimercapto-1,3,5-triazine (abbreviation: TDCA) (C) per 100 parts by weight. rubber composition. 2. Further, 5 parts by weight or less of dicyclohexylamine salt of 2-mercaptobenzothiazole ( The rubber composition according to claim 1, containing (abbreviation: MDCA) (D). 3. Furthermore, 5 parts by weight or less of sulfur (E) and/or TDCA (C ), MDCA (
Claim 1 containing an organic sulfur-containing compound (F) other than D)
The rubber composition described in . 4. The rubber composition further contains 10 parts by weight or less of MDCA (D) based on 100 parts by weight of the chlorinated polyethylene rubber (A) and/or the maleic anhydride-modified chlorinated polyethylene rubber (B). The rubber composition described in .