JPH01203731A - Belt - Google Patents

Abstract

PURPOSE:To improve oil proof, heat resistance or the like by mixing copolymeric rubber made up of copolymerizing an unsaturated carboxylic acid monomer, a filler and a vulcanizing agent in a rubber ingredient consisting of butadiene and acrylonitrile, in an automobile engine timing belt or the like. CONSTITUTION:A copolymeric unsaturated carboxylic acid monomer is copolymerized as much as 0.1-15wt.% with 100wt.% of a rubber ingredient consisting of butadiene 45-80wt.% and acrylonitrile 20-55wt.%, composing a polyphyletic copolymer. Then, such partial hydro-polyphyletic copolymeric rubber as made up of hydrogenizing a carbon-carbon double bond part as much as at least more than 70% is secured. A filler and a vulcanizing agent are mixed in this polyphyletic copolymeric rubber and a vulcanized rubber constituent is prepared, forming a belt with this constituent. In this connection, as for this copolymeric unsaturated carboxylic acid monomer, acrylic acid, methacrylic acid, crotonic acid, oleic acid or the like are suitable for it.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an oil-resistant belt with improved heat resistance and abrasion resistance. It is substantially formed of a vulcanized rubber composition made by adding a filler such as carbon black and a vulcanizing agent to a chemically bonded acrylonitrile-butadiene rubber in which a certain amount or more of the butadiene portion is hydrogenated. The present invention relates to a belt having heat resistance, abrasion resistance, and oil resistance, and is suitable as a timing belt for an automobile engine.

(Prior Art and Problems) In recent years, in the automobile industry, engine timing belts are required to have excellent oil resistance and heat resistance due to the demand for more compact engine compartments. In addition, due to the demand for maintenance belts for automobiles, the demand for belts with excellent wear resistance is increasing.

Acrylonitrile-butadiene copolymer rubber (hereinafter referred to as “N”)
BRJ (abbreviated as BRJ) is widely used for oil-resistant belts, but it generally has poor heat resistance and weather resistance. proposed to improve heat resistance and weather resistance by hydrogenating the butadiene moiety of NBR. However, timing belts using this hydrogenated NBR still do not have sufficient wear resistance and cannot completely meet the demand for maintenance-free belts.

(Means for Solving the Problems) As a result of intensive studies to improve the above problems, the present inventors have developed a copolymerizable unsaturated carboxylic acid monomer as a third component for a rubber component consisting of butadiene and acrylonitrile. The carbon-carbon double bond portion of the multi-component copolymer obtained by copolymerizing a specific amount of at least one type of polymer is at least 7
If you use a vulcanized rubber composition made by blending a filler such as carbon black and a vulcanizing agent with a partially hydrogenated multi-component copolymer rubber that has been hydrogenated at least 0%, it will have excellent oil resistance, weather resistance, and heat resistance. The inventors have discovered that an excellent belt with excellent wear resistance and significantly improved wear resistance can be obtained, leading to the present invention.

That is, the present invention provides butadiene 4tj~? Rubber component 1 consisting of θ heavy weight % and acrylonitrile 2O-jJ-% by weight
0.00% by weight, the amount of copolymerizable unsaturated carboxylic acid monomer is 0.00% by weight. Filler and vulcanizing agent to a partially hydrogenated multi-component copolymer rubber in which at least 70% or more of the carbon-carbon double bonds of the multi-component copolymer obtained by copolymerizing /~/Yu weight% are hydrogenated. The object of the present invention is to provide a belt having excellent oil resistance, weather resistance, heat resistance, and abrasion resistance, which is substantially formed from a vulcanized rubber composition containing the following.

The belt of the present invention will be described in detail below.

Is the ratio of butadiene to acrylonitrile in the hydrogenated partially hydrogenated multicomponent copolymer rubber used in the present invention to butadiene data? θwt% and acrylonitrile 2O−
tj% by weight, more preferably butadiene! Q~
70% by weight and acrylic, ronitrile jO-J-0% by weight
It is. If the amount of acrylonitrile is too large, the cold resistance and rubbery properties will be insufficient, and if the amount is too small, the oil resistance will be insufficient. selected as a suitable range. In the present invention, 0.0% of the copolymerizable unsaturated carboxylic acid monomer is added to 100% by weight of the rubber component consisting of butadiene and acrylonitrile. /~/j% by weight is copolymerized to obtain a multicomponent copolymer.

This multicomponent copolymer is prepared by emulsion polymerization of butadiene, acrylonitrile, and a copolymerizable unsaturated carboxylic acid monomer in the presence of a redox initiator or the like. In addition, the amount of copolymerizable unsaturated carboxylic acid monomer is 0.7% by weight.
If it is less than 15% by weight, the effect of improving wear resistance will be diminished, and if it exceeds 15% by weight, there will be a marked tendency for the cold resistance performance to deteriorate, which is not preferable.

The unsaturated carboxylic acid monomer to be copolymerized with butadiene and acrylonitrile used in the present invention is preferably a compound selected from at least one of acrylic acid, methacrylic acid, crotonic acid, and oleic acid.

The partially hydrogenated copolymer rubber used in the present invention has 70% or more of the carbon-carbon double bond portion of the above multi-component polymer,
It is preferably obtained by hydrogenating 20% or more, more preferably 0% or more. Such hydrogenation treatment removes the carbon-carbon of the butadiene moiety while retaining the nitrile group of the acrylonitrile moiety forming the multicomponent polymer of the present invention.
selectively hydrogenating a carbon double bond,
U.S. Patent No. 3100-37, Special Publication No. 4tj-j
Wako 7! This is carried out by a commonly known method disclosed in Japanese Patent Application Laid-open No. 10-7/1<r1, etc.

Next, the belt which is the object of the present invention is manufactured by adding a filler such as carbon black or silica, a vulcanizing agent such as sulfur or an organic peroxide, and a tetramethylthiuram disulfide to the multi-component partially hydrogenated copolymer rubber. A vulcanization accelerator and, if necessary, additives such as plasticizers and anti-aging agents used in ordinary rubber compositions are added, and the mixture is mixed, cross-wired, and mixed according to conventional methods.
It is prepared by vulcanization. In addition, when cross-talking, use polyvinyl chloride (PVC), ethylene propylene terpolymer (EPDM), fluororubber (FKM), fluorosilicone rubber (FQM), epichlorohydrin rubber (E
CO), liquid NBR and other polymer compounds may be used in combination.

There are no particular restrictions on the structure of the belt of the present invention, as long as the entire belt or the rubber layer on the back or inner side of the belt is substantially formed of the vulcanized rubber composition. Specifically, as shown in Figure 1, the rubber layer on the back side ■ and the inside side of the belt is made of a tensile material ■ made of fibers such as nylon fiber, polyester fiber, glass fiber, carbon fiber, etc. as a core. It is formed from such a vulcanized rubber composition, and furthermore, the inner rubber layer has teeth parts (■) and groove parts (■) alternately at a constant pitch in the longitudinal direction of the belt, as necessary, and the surfaces of the teeth and groove parts. Examples include toothed belts to which a cover layer (1) made of canvas coated with such a vulcanized rubber composition adheres.

There are no particular restrictions on the type of belt used in the present invention (such as power transmission belts such as timing belts or conveyor belts that are repeatedly deformed in high-temperature air or oil for long periods of time, etc.). There are no restrictions as long as the belt requires properties such as durability and weather resistance.

Hereinafter, the present invention will be explained in detail with reference to examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

Examples/- 3 and Comparative Examples 7-5 A multi-component copolymer consisting of butadiene-acrylonitrile-unsaturated carboxylic acid was prepared according to the polymerization recipe shown in Table 1. After dissolving these copolymers in tetrahydrofuran, a hydrogenation catalyst (Pd-carbon) was added, the mixture was pressurized with hydrogen to 5θ/cd, and a hydrogenation reaction was carried out at 15° C. for an hour. In the recovered polymer, no reduction of the nitrile groups was observed, and only the carbon-carbon double bonds were each 90% hydrogenated. Note that the hydrogenation rate was determined based on the iodine value.

Next, these polymers were kneaded in a Banbury mixer according to the formulation shown in Table 2. The resulting mixture was heated to iqo℃,
Press vulcanization was carried out for 20 minutes to prepare test vulcanizates, and Table 3 shows the results of measuring their physical properties.

For comparison, in Comparative Examples/and Co, a copolymer containing no unsaturated carboxylic acid of the present invention was used, and a copolymer that was not hydrogenated and a copolymer that was hydrogenated were prepared in the same manner as in the example. A vulcanizate was obtained. Furthermore, comparative example 3~! In this case, a vulcanizate was obtained in the same manner as in the example without hydrogenating the terpolymer used in Examples/--3. Table 3 shows the results of these physical property measurements. In addition, in Table 3, TB: tensile strength;
ΔTB: rate of change in tensile strength, EB: elongation, ΔEB: rate of change in elongation, H8: hardness, ΔH8: rate of change in hardness.

In addition, in the ozone resistance in the same table, "NC" means no cracks, "B or C-/~g" means J'ISK/,
The deterioration state described in Table t of No. 30/ is shown.

(Effects of the Invention) According to the present invention, a belt having excellent oil resistance, weather resistance, and fatigue resistance can be obtained, and particularly when used in a timing belt for an automobile, etc., a remarkable effect is exhibited.

[Brief explanation of the drawing]

FIG. 1 shows a specific example of the belt of the present invention. ■: Tensile body, ■: Back part of belt, ■: Inner part of the belt, ■Two cover layers Sender: Mitsubishi Chemical Industries, Ltd. Representative Patent Attorney Hase - 7 others Akira 1 Ward 4 Φ b

Claims (2)

[Claims] (1) Obtained by copolymerizing 0.1 to 15% by weight of a copolymerizable unsaturated carboxylic acid monomer to 100% by weight of a rubber component consisting of 45 to 80% by weight of butadiene and 20 to 55% by weight of acrylonitrile. Formed from a vulcanized rubber composition obtained by blending a filler and a vulcanizing agent with a partially hydrogenated multicomponent copolymer rubber in which at least 70% or more of the carbon-carbon double bonds of the multicomponent copolymer are hydrogenated. A belt characterized by: (2) The belt according to claim 1, wherein the copolymerizable unsaturated carboxylic acid monomer is a compound selected from at least one of acrylic acid, methacrylic acid, crotonic acid, and oleic acid.