JP2000336211A - Chloroprene rubber composition and belt using the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition excellent in adhesion to fibers by blending a specific amount of at least either of a thiazole-based or a sulfenamide-based rubber accelerator with a chloroprene rubber. SOLUTION: 0.5-3 pts.wt. of at least either of a thiazole-based or a sulfenamide-based rubber accelerator is blended with 100 pts.wt. of a chloroprene rubber. 0.5-3 pts.wt. of sulfur is further blended. Non-sulfur-modified chloroprene rubbers have more significant effect of increasing adhesion. Thiazole-based or sulfenamide-based rubber accelerators include compounds of formulae I and II. In formula I, X is H, formula III, 1/2 Zn, formula IV or formula V and in formula II, R is formula VI and R' is H, R and R' are each t-Bu, R is H and R' is formula VII, or R and R' are each formula VIII. This composition can be applied for fibers generally used for reinforcement of a rubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chloroprene rubber compounding composition, and more particularly to a chloroprene rubber composition having excellent adhesion to organic and inorganic fiber materials.

[0002]

2. Description of the Related Art Conventionally, rubber has been used as a material for belts used in power transmission applications and the like, and is usually reinforced by embedding a core wire or canvas in rubber or providing it on the surface. ing.

[0003] Chloroprene rubber is a rubber typically used as a rubber for a belt material. Chloroprene rubber has excellent properties in terms of heat resistance, ozone resistance, weather resistance, oil resistance, chemical resistance and the like, and is used for a wide range of applications.

[0004] It is important to bond rubber with a fiber material such as a cord or a cover canvas. If these bonds are insufficient, the reinforcing effect of the fiber cannot be sufficiently obtained. Usually, in order to bond the rubber composition and the fiber material, the fibers are so-called RF.
A method of treating with an L (resorcinol / formalin / rubber latex) solution or treating with an epoxy compound or an isocyanate compound to further improve the adhesiveness is generally performed.

[0005] Further, HR in which diene rubber is mixed with hydrated white carbon, resorcinol or a resorcinol derivative and a methylene donor such as hexamethylenetetramine.
The H method is also used.

However, these adhesive compositions have a good initial adhesive strength, but have a disadvantage that the adhesive strength after thermal aging is greatly reduced, or the adhesive surface is hardened by heat and the adhesive function is easily lost. are doing. Furthermore, in recent years, in order to improve the heat resistance of rubber, the method of vulcanizing rubber has been changed to sulfur or a sulfur compound, and an organic peroxide has been used.

However, when cross-linked with an organic peroxide, R
When treated with the FL solution, the resorcinol resin was attacked by the organic peroxide and hardened, and the deterioration of the adhesive surface and the fiber was increased. The same applies to the case of treatment with an epoxy compound or an isocyanate compound as in the case of the RFL solution. On the other hand, HR
The method H has a disadvantage that a sufficient initial adhesive strength cannot be obtained.

It is an object of the present invention to solve the above-mentioned problems and to provide a rubber composition and a belt having excellent adhesion to fibers.

[0009]

According to the first aspect of the present invention, there is provided a rubber composition mainly composed of chloroprene rubber and having excellent adhesion to fibers.
It is characterized in that 0.5 to 3 parts by weight of a thiazole vulcanization accelerator or a sulfamide-based vulcanization accelerator and 0.5 to 3 parts by weight of sulfur are added to 0 part by weight.

[0010] By blending such a specific vulcanization accelerator and sulfur, the adhesive strength between the chloroprene rubber and the fiber becomes excellent.

[0011] In claim 2, as the chloroprene rubber,
It is said that a non-sulfur-modified type rubber is used, and in the case of a non-sulfur-modified type chloroprene rubber, the improvement in the adhesive force between the fiber and the fiber according to the present invention is large, and a remarkable remarkable effect can be exhibited. it can.

According to a third aspect of the present invention, in the belt made of a chloroprene rubber composition reinforced with fibers, 0.5 to 3 parts by weight of a thiazole vulcanization accelerator or a sulfamide vulcanization accelerator is added to 100 parts by weight of chloroprene rubber. Parts by weight and 0.5 to 3 parts by weight of sulfur.

By blending such a specific vulcanization accelerator and sulfur, the adhesive strength between the chloroprene rubber and the fiber becomes excellent.

In claim 4, a non-sulfur-modified type rubber is used as the chloroprene rubber. When a non-sulfur-modified type chloroprene rubber is used, the adhesive force in the present invention is greatly improved, and a remarkable effect is obtained. Can be demonstrated.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a chloroprene rubber composition having excellent adhesion to fibers. The rubber composition of the present invention comprises a thiazole-based vulcanization accelerator or 100 parts by weight of chloroprene rubber. 0.5 to 3 parts by weight of at least one of the sulfenamide-based vulcanization accelerators and 0.1% of sulfur.
It is a chloroprene rubber composition blended with 5 to 3 parts by weight and a belt using such a chloroprene rubber.

By adding the above-mentioned compounding agent to the chloroprene rubber in a predetermined amount, the adhesiveness with the fiber is improved, and in a use such as a rubber belt reinforced with a core, a canvas, or a short fiber, the core is used. The present invention can provide an excellent belt having a long life and little problems such as popping out of the canvas and peeling of the canvas.

The compounding amount of the thiazole vulcanization accelerator or the sulfenamide vulcanization accelerator is 100 parts of chloroprene rubber.
0.5 to 3 parts by weight with respect to parts by weight,
If the amount is less than 0.5 part by weight, sufficient adhesive strength cannot be obtained. If the amount exceeds 3 parts by weight, the vulcanization rate becomes too fast, and there is a problem that rubber processing cannot be performed.

Further, the compounding amount of sulfur is chloroprene rubber 1
0.5 to 3 parts by weight with respect to 00 parts by weight,
If the amount is less than 0.5 part by weight, a sufficient adhesive strength cannot be obtained. If the amount exceeds 3 parts by weight, the vulcanization rate becomes too fast or too slow, so that there is a problem that rubber cannot be processed.

The chloroprene rubber of the present invention may be either a sulfur-modified type or a non-sulfur-modified type, and the non-sulfur-modified type chloroprene rubber is more preferably a thiazole vulcanization accelerator. Alternatively, the effect of improving the adhesive force by adding a sulfenamide vulcanization accelerator is more remarkable.

The thiazole-based vulcanization accelerator is a compound represented by the following general formula: mercaptobenzothiazole, benzothiazyl sulfide, zinc salt of mercaprobenzothiazole, (dinitrophenyl) mercaptobenzothiazole, (N, N'-diethylthiocarbamoylthio) benzothiazole and the like.

[0021]

Embedded image

Next, the sulfenamide-based vulcanization accelerator is a compound represented by the general formula (2).
-Cyclohexylbenzothiazylsulfenamide, N
-T-butylbenzothiazylsulfenamide, N-oxydiethylenebenzothiazylsulfenamide,
N, N'dicyclohexylbenzothiazylsulfenamide, (morpholinodithio) benzothiazole and the like can be mentioned.

[0023]

Embedded image

The fibers which can be bonded well to the chloroprene rubber composition of the present invention are not particularly limited, and are generally used for reinforcing rubber such as glass fibers, aramid fibers, polyamide fibers and polyester fibers. Any fiber can be used.

When the chloroprene rubber composition of the present invention is bonded to a fiber, the fiber is subjected to a bonding treatment. The method of the bonding treatment is not particularly limited, and is a bonding treatment generally used for bonding with chloroprene rubber.
A method is used in which the fibers are dipped in an L (resorcinol-formalin latex) treatment liquid and dried. R
Other than the FL treatment, a pretreatment with isocyanate or epoxy, or a rubber paste obtained by dissolving rubber in a solvent may be attached by means such as soaking.

In addition to the above-mentioned thiazole vulcanization accelerator or sulfenamide vulcanization accelerator and sulfur, compounding agents such as antioxidants, reinforcing agents, fillers and plasticizers usually compounded in chloroprene rubber. Does not depart from the present invention at all.

Examples of the anti-aging agent include amine-based, phenol-based and benzimidazole-based anti-aging agents.

Examples of the filler and reinforcing agent include clay, calcium carbonate, barium sulfate, silica, hydrated silicate, titanium oxide, carbon black and the like.

As the plasticizer, naphthenic oils, aromatic oils and the like can be used.

The belt according to the third and fourth aspects of the present invention is a belt in which a rope made of fibers is spirally embedded in rubber, and a belt with a cord or a canvas is embedded in rubber or laminated and adhered to the rubber surface. By using a chloroprene rubber composition as described above as a rubber at least in a portion of the belt in contact with the fiber, the adhesion between the fiber material such as a core wire and the rubber is strong. For example, it is possible to obtain a belt with a long service life by preventing problems such as jumping of a core wire during running of the belt and peeling of canvas laminated on the belt surface.

FIG. 1 is a sectional perspective view of an essential part showing an example in which the present invention is applied to a toothed belt 1. As shown in FIG. The toothed belt 1 includes a back portion 2 and a tooth portion 3, and a core wire 4 is embedded in the back portion 2 in a spiral shape. The surface of the tooth portion 3 is covered with a tooth cloth 5.

Here, the rubber forming the back portion 2 in which the core wire 4 is embedded is a chloroprene rubber composition, and 100 parts by weight of chloroprene rubber contains at least a thiazole vulcanization accelerator or a sulfenamide vulcanization accelerator. 0.5 for one
Chloroprene rubber composition containing 0.5 to 3 parts by weight of sulfur and 0.5 to 3 parts by weight of sulfur. The adhesion between the back part 2 and the core wire 4 is very strong. In this case, a failure due to jumping out of the core wire is less likely to occur, and the belt can have a long life.

As the core wire 4, general fibers such as glass fiber, aramid fiber, polyamide fiber, polyester fiber and the like can be used.

The chloroprene rubber is preferably a non-sulfur-modified chloroprene rubber.
The effect of the present invention is more remarkable than when sulfur-modified chloroprene rubber is used.

Further, in the toothed belt 1, the rubber forming the tooth portion 2 is added to 100 parts by weight of the same chloroprene rubber as the back portion 3 with at least one of a thiazole vulcanization accelerator or a sulfenamide vulcanization accelerator. By forming the chloroprene rubber composition containing 5 to 3 parts by weight of sulfur and 0.5 to 3 parts by weight of sulfur, the adhesive strength between the tooth portion 2 and the tooth cloth 5 can be increased.

Although the example of the toothed belt is given, the type of belt in the belt of the present invention is not limited, and a flat belt, a low edge belt, a wrapped belt,
The present invention can be applied to a belt of a type such as a ribbed belt, and can increase not only the adhesive strength between a core wire and a canvas but also the fiber and other short fibers blended in rubber.

[0037]

EXAMPLES Next, the effects of the present invention were confirmed with reference to Examples and Comparative Examples.

Example 1 The belt was a toothed belt 1 as shown in FIG. 1. The rubber forming the teeth 2 and the back 3 was a thiazole-based vulcanization accelerator based on 100 parts by weight of chloroprene rubber. A rubber composition containing 0.5 part by weight, 0.5 part by weight of sulfur, and other components as shown in Table 1 was used. Non-sulfur-modified chloroprene rubber S-40 manufactured by Denki Kagaku was used, and dibenzothiazyl disulfide (MBTS) was used as a thiazole vulcanization accelerator.

A core made of glass fiber (ECG-150)
-3/0) were dip-treated with vinylpyridine latex to form a strip having a width of 25 mm and the chloroprene rubber composition.
90 ° using a sample obtained by vulcanization under the conditions of
Was subjected to a peel test. Table 1 shows the results.

Further, a toothed belt for light-conveyance use was prepared using a cord made of the same chloroprene rubber composition and glass fiber as the sample of the peeling test, and two belts as shown in the layout of FIG. A running test was conducted in which the card was pinched and transported on the back of the device. The number of card transports until a belt failure occurred was measured, and the failure phenomenon was observed. Table 1 shows the results.

The light-conveying belt has a plurality of teeth along the longitudinal direction of the belt, and has a back in which the cord is buried. A tooth cloth is adhered to the surface of the teeth. I have. The pitch of the teeth was 2 mm, the number of teeth was 66, the belt width was 250 mm, and a satin canvas having elasticity was used as the tooth cloth.

Example 2 A peel test was carried out using the same rubber composition as in Example 1 except that 1 part by weight of a thiazole vulcanization accelerator and 1 part by weight of sulfur were mixed with 100 parts by weight of chloroprene rubber. A running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Blending of chloroprene rubber composition,
Table 1 shows the results of the peeling test and the results of the running test.

Example 3 A peel test was conducted using the same rubber composition as in Example 1 except that 3 parts by weight of a thiazole vulcanization accelerator and 3 parts by weight of sulfur were mixed with 100 parts by weight of chloroprene rubber. A running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Blending of chloroprene rubber composition,
Table 1 shows the results of the peeling test and the results of the running test.

Example 4 Exfoliation was performed using the same rubber composition as in Example 2 except that 1 part by weight of a thiazole vulcanization accelerator different from those in Examples 1 to 3 was added to 100 parts by weight of chloroprene rubber. A test was performed, and a running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the tooth portions 2 and the back portion 3. Table 1 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

The thiazole vulcanization accelerator used in this example is mercaptobenzothiazole (MBT).

Example 5 Example 2 was repeated except that 1 part by weight of a sulfenamide-based vulcanization accelerator was used instead of the thiazole-based vulcanization accelerator per 100 parts by weight of chloroprene rubber.
A peeling test was performed using the same rubber composition as that described above, and a running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Table 1 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

The sulfenamide vulcanization accelerator used in this example is N-cyclohexyl-2-benzothiazylsulfenamide (CBS).

Example 6 A peeling test was conducted using the same rubber composition as in Example 1 except that 3 parts by weight of a thiazole vulcanization accelerator and 1 part by weight of sulfur were mixed with 100 parts by weight of chloroprene rubber. A running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Blending of chloroprene rubber composition,
Table 1 shows the results of the peeling test and the results of the running test.

Example 7 Example 2 was repeated except that 100 parts by weight of chloroprene rubber and 3 parts by weight of a sulfenamide-based vulcanization accelerator were used instead of the thiazole-based vulcanization accelerator.
A peeling test was performed using the same rubber composition as that described above, and a running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Table 1 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

The sulfenamide vulcanization accelerator used in this example is N-cyclohexyl-2-benzothiazylsulfenamide (CBS).

Example 8 A peel test was conducted using the same rubber composition as in Example 1 except that 1 part by weight of a thiazole vulcanization accelerator and 3 parts by weight of sulfur were mixed with 100 parts by weight of chloroprene rubber. A running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Blending of chloroprene rubber composition,
Table 1 shows the results of the peeling test and the results of the running test.

Comparative Example 1 A peeling test was conducted using the same rubber composition as in Example 1 except that no vulcanization accelerator and no sulfur were blended with respect to 100 parts by weight of chloroprene rubber.
A running test was conducted with a toothed belt using the same chloroprene rubber composition as the rubber forming the tooth portions 2 and the back portion 3.
Table 2 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

Comparative Example 2 A peel test was conducted using the same rubber composition as in Example 1 except that 1 part by weight of a thiazole vulcanization accelerator was added to 100 parts by weight of chloroprene rubber and no sulfur was added. A running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Table 2 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

[Comparative Example 3] A peeling test was conducted using the same rubber composition as in Example 1 except that 100 parts by weight of chloroprene rubber and 1 part by weight of sulfur were not mixed with the thiazole vulcanization accelerator. A running test was conducted with a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Table 2 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

Comparative Example 4 The same rubber composition as in Example 1 was used except that 0.2 part by weight of a thiazole-based vulcanization accelerator and 0.2 part by weight of sulfur were added to 100 parts by weight of chloroprene rubber. A peeling test was conducted by using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3, and a running test was conducted. Table 2 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

Comparative Example 5 A peeling test was conducted using the same rubber composition as in Example 1 except that 5 parts by weight of a thiazole-based vulcanization accelerator and 1 part by weight of sulfur were added to 100 parts by weight of chloroprene rubber. A running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Blending of chloroprene rubber composition,
Table 2 shows the results of the peeling test and the results of the running test.

Comparative Example 6 The same rubber composition as in Example 1 except that 100 parts by weight of chloroprene rubber was replaced with 5 parts by weight of a sulfenamide-based vulcanization accelerator and 1 part by weight of sulfur instead of the thiazole-based one. A peel test was performed using the material, and a running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Table 2 shows the blending of the chloroprene rubber composition, the results of the peeling test, and the results of the running test.

Comparative Example 7 A peeling test was conducted using the same rubber composition as in Example 1 except that 1 part by weight of a thiazole-based vulcanization accelerator and 5 parts by weight of sulfur were added to 100 parts by weight of chloroprene rubber. A running test was performed using a toothed belt using the same chloroprene rubber composition as the rubber forming the teeth 2 and the back 3. Blending of chloroprene rubber composition,
Table 2 shows the results of the peeling test and the results of the running test.

[0059]

[Table 1]

[0060]

[Table 2]

As can be seen from Tables 1 and 2, Comparative Example 1 in which no thiazole-based vulcanization accelerator or sulfenamide-based vulcanization accelerator was blended with sulfur, or only either vulcanization accelerator or sulfur was used. In Comparative Examples 2 and 3, in which no adhesive force was exerted between the rubber and the fiber in the peeling test, failure occurred early in the result of the running test.

Further, even in the case where both the vulcanization accelerator and the sulfur were blended, the adhesive strength was small even in Comparative Example 4 in which the blending amount was smaller than the predetermined amount. Has failed.

Next, in Comparative Examples 5 and 6 in which the blending amount of the vulcanization accelerator was too large than the predetermined amount, although sufficient adhesion was exhibited in the peeling test, a problem occurred in the running test. In Comparative Example 5, the core wire was exposed at an early stage due to wear of the back surface. This is because the addition of a large amount of a thiazole-based vulcanization accelerator that acts as a vulcanization retarder (retarder) delays vulcanization, resulting in insufficient vulcanization, resulting in a decrease in hardness and rapid wear on the back surface. .

In Comparative Example 6, the tooth pattern of the belt was not sufficiently formed and the tooth pattern was defective. This is because the addition of a large amount of a sulfenamide-based vulcanization accelerator acting as a vulcanization accelerator speeds up vulcanization, and vulcanization proceeds before the rubber at the tooth portion forms a tooth shape.

[0065]

As described above, according to the first aspect of the present invention, in a rubber composition mainly composed of chloroprene rubber and having excellent adhesion to fibers, thiazole vulcanization is performed with respect to 100 parts by weight of chloroprene rubber. 0.5 to 3 parts by weight of an accelerator or a sulfamide vulcanization accelerator and 0.5 to 3 parts by weight of sulfur
-3 parts by weight.

By blending such a specific vulcanization accelerator and sulfur, the adhesive strength between the chloroprene rubber and the fiber becomes excellent.

In claim 5, as the chloroprene rubber,
It is said that a non-sulfur-modified type rubber is used, and in the case of a non-sulfur-modified type chloroprene rubber, the improvement in the adhesive force between the fiber and the fiber according to the present invention is large, and a remarkable remarkable effect can be exhibited. it can.

According to a third aspect of the present invention, in the belt made of a chloroprene rubber composition reinforced with fibers, 0.5 to 3 parts by weight of a thiazole vulcanization accelerator or a sulfamide vulcanization accelerator is added to 100 parts by weight of chloroprene rubber. Parts by weight and 0.5 to 3 parts by weight of sulfur.

By blending such a specific vulcanization accelerator and sulfur, the adhesion between the chloroprene rubber and the fiber becomes excellent.

In claim 4, a non-sulfur-modified type rubber is used as the chloroprene rubber. When a non-sulfur-modified type chloroprene rubber is used, the adhesive force in the present invention is greatly improved, and a remarkable effect is obtained. Can be demonstrated.

[Brief description of the drawings]

FIG. 1 is a sectional perspective view of a main part of a toothed belt as an example of the present invention.

FIG. 2 is a schematic diagram showing a layout of a running test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Tooth part 3 Back part 4 Core wire 5 Tooth cloth

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16G 1/06 F16G 1/06 // B29K 9:00 F term (reference) 3F049 BA12 LA15 4F213 AA45A AB03 AB16 AD16 AD18 AE10 AG03 AG17 AH12 WA15 WA41 WA53 WA87 WB01 WB11 4J002 AC091 CF002 CL002 CL062 DA047 DL008 EV276 EV326 FA042 FA048 FD010 FD020 FD070 FD147 FD147 FD156 GM01

Claims (4)

[Claims] 1. A rubber composition mainly comprising chloroprene rubber, wherein 0.5 to 3 parts by weight of at least one of a thiazole vulcanization accelerator and a sulfamide vulcanization accelerator is blended with respect to 100 parts by weight of chloroprene rubber. A chloroprene rubber composition having excellent adhesion to fibers. 2. The chloroprene rubber composition according to claim 1, wherein a non-sulfur-modified rubber is used as the chloroprene rubber. 3. A belt comprising a chloroprene rubber composition reinforced with fibers, wherein at least one of a thiazole vulcanization accelerator or a sulfamide vulcanization accelerator is 0.5 to 3 parts by weight based on 100 parts by weight of chloroprene rubber. A belt characterized by being blended in parts. 4. The belt according to claim 1, wherein a non-sulfur-modified rubber is used as the chloroprene rubber.