JP2013001837A - Adhesive rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive rubber composition which can easily stick the rubbers of conveyor belts, etc. to each other without using rubber cement, and which is excellent also in adhesiveness after vulcanization.SOLUTION: The adhesive rubber composition contains (A) 100 pts.mass of a rubber component containing ≥60 mass% of at least one selected from the group consisting of natural rubber and isoprene rubber, (B) 2-4 pts.mass of sulfur containing ≥60 mass% of insoluble sulfur which is a component insoluble in carbon disulfide, (C) 5-15 pts.mass of a C5 petroleum resin, and (D) 0.05-10 pts.mass of stearic acid, and further contains (E) 0.1-1 pt.mass of a benzothiazole-based vulcanization accelerator if necessary.

Description

  The present invention relates to an adhesive rubber composition. More specifically, the present invention relates to an adhesive rubber composition having high adhesive strength and high adhesive strength without using rubber cement, and further to an adhesive rubber composition for conveyor belts.

Conventionally, in an endless operation of a conveyor belt (for example, an operation in which a conveyor belt of several hundreds of meters is joined at the end where the conveyor belt is used), when rubber is bonded, rubber cement is not added. Vulcanization adhesion has been carried out in combination with a sulfur adhesive rubber composition. There are the following two reasons for using the rubber cement together.
1. Since the adhesiveness is increased and the rubber is stabilized in a state where the rubbers are adhered to each other, the molding work is facilitated.
2. Adhesive strength at the site where the rubbers are bonded together, particularly dynamic adhesiveness, is increased, and rubber strength is maintained.
However, rubber cement usually contains an organic solvent that easily volatilizes such as toluene and xylene, and the organic solvent is scattered to the atmosphere. Therefore, it is necessary to dry after bonding, and there is a problem that work efficiency is poor. Furthermore, since organic solvents fall under the dangerous materials of the Fire Service Act, there are problems such as requiring care and troublesome transportation, storage and use. Nevertheless, the above advantages 1. And 2. For this reason, rubber cement is required for the endless operation of the conveyor belt and continues to be used.
On the other hand, in order to solve the problems of the rubber cement, a method for performing an endless operation of the conveyor belt without using the rubber cement has been developed. Specifically, it is a method in which ultra high molecular weight polyethylene having a molecular weight of 1,000,000 or more produced by a specific method is interposed in an endless joint or repair part of a conveyor belt and integrally joined (see Patent Document 1).

JP-A-6-134863

However, in the method described in Patent Document 1, it is necessary to use a special material called ultra-high molecular weight polyethylene having a molecular weight of 1 million or more produced by a scraping method as a heat vulcanization joining material, and it is difficult to perform endless work. There is a problem of becoming.
Therefore, the subject of this invention is providing the adhesive rubber composition which is easy to stick rubbers, such as a conveyor belt, without using a rubber cent, and is excellent also in the adhesiveness after vulcanization.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found an adhesive rubber composition containing a specific rubber component, a specific sulfur component, a C5 petroleum resin, and stearic acid in a specific blending amount. For example, it has been found that it is easy to stick rubbers such as conveyor belts together without using rubber cents, and the adhesiveness after vulcanization is excellent.

That is, the present invention relates to the following [1] to [3].
[1] (A) 100 parts by mass of a rubber component containing 60% by mass or more of at least one selected from the group consisting of natural rubber and isoprene rubber;
(B) 2 to 4 parts by mass of sulfur containing 60% by mass or more of insoluble sulfur which is a component insoluble in carbon disulfide,
An adhesive rubber composition comprising (C) 5 to 15 parts by mass of a C5 petroleum resin, and (D) 0.05 to 10 parts by mass of stearic acid.
[2] The adhesive rubber composition according to [1], further including 0.1 to 1 part by mass of (E) a benzothiazole vulcanization accelerator.
[3] The adhesive rubber composition according to [1] or [2], which is for a conveyor belt.

  The adhesive rubber composition of the present invention can strongly stick rubbers without using rubber cement, and has high adhesion after vulcanization without using rubber cement. Further, the adhesive rubber composition of the present invention is less likely to be vulcanized during storage, and further, when mixed with a mixer to obtain a composition, it is difficult to adhere to the mixer casing, resulting in high working efficiency. Useful.

It is a schematic diagram which shows the sample used for the adhesive test in the Example. It is a schematic diagram which shows the sample used for the dynamic adhesiveness test in the Example.

[Adhesive rubber composition]
The adhesive rubber composition of the present invention comprises (A) 100 parts by mass of a rubber component containing 60% by mass or more of at least one selected from the group consisting of natural rubber and isoprene rubber, and (B) insoluble in carbon disulfide. 2 to 4 parts by mass of sulfur containing 60% by mass or more of insoluble sulfur which is a major component, (C) 5 to 15 parts by mass of C5 petroleum resin, and (D) 0.05 to 10 parts by mass of stearic acid.
Hereinafter, each component contained in the adhesive rubber composition of the present invention will be described in detail.

[(A) Rubber component containing 60% by mass or more of at least one selected from the group consisting of natural rubber and isoprene rubber]
The component (A) is a rubber component containing at least 60% by mass (preferably natural rubber or isoprene rubber) selected from the group consisting of natural rubber and isoprene rubber from the viewpoint of tackiness and adhesiveness. There must be. From this viewpoint, the rubber component has a content of natural rubber and / or isoprene rubber of preferably 65% by mass or more, more preferably 70% by mass or more, further preferably 75% by mass or more, and particularly preferably 78% by mass. That's it.
The component (A) may contain a diene rubber other than natural rubber or isoprene rubber. Examples of the diene rubber include butadiene rubber, isoprene rubber, butadiene / isoprene rubber, styrene / butadiene rubber, Examples thereof include styrene / isoprene rubber, styrene / isoprene / butadiene rubber, ethylene / propylene / diene rubber, butyl rubber, and halogenated butyl rubber. Among these, as the diene rubber, butadiene rubber, isoprene rubber, and styrene / butadiene rubber are preferable, and styrene / butadiene rubber is more preferable from the viewpoint of the effect of the present invention.

((B) Sulfur containing 60% by mass or more of insoluble sulfur which is a component insoluble in carbon disulfide)
The component (B) is sulfur containing 60% by mass or more of sulfur which is insoluble in carbon disulfide, so-called insoluble sulfur. By containing the component (B) in the adhesive rubber composition, the adhesiveness after vulcanization is increased.
Normally, sulfur itself is not highly compatible with various rubber components, but insoluble sulfur is more soluble (compatible) with component (A) than soluble sulfur (sulfur soluble in carbon disulfide). However, when the component (B) is blended in order to improve the adhesiveness, it has been found that the “stickiness” suddenly decreases when the amount exceeds a certain amount. From these viewpoints, the content of the component (B) is 2 to 4 parts by mass, preferably 2.5 to 4 parts by mass, more preferably 3 to 4 parts by mass with respect to 100 parts by mass of the component (A). It is.

((C) C5 petroleum resin)
The C5 petroleum resin as component (C) is a petroleum resin mainly composed of a C5 fraction obtained by cracking naphtha, and the content of the C5 fraction is 70% by mass or more (preferably 80% by mass or more, more 90% by mass or more) petroleum resin. The C5 petroleum resin may contain a C4 petroleum resin that can be usually contained.
By containing (C) component, the adhesiveness and adhesiveness of an adhesive rubber composition become high. However, it has been found that the “adhesiveness” suddenly decreases when a certain amount is exceeded. Moreover, when (C) component was contained too much, when preparing an adhesive rubber composition, the problem of becoming easy to adhere to a mixer casing also arose. From these viewpoints, the content of the component (C) is 5 to 15 parts by mass, preferably 5 to 13 parts by mass, more preferably 5 to 11 parts by mass with respect to 100 parts by mass of the component (A). .

((D) stearic acid)
The adhesive rubber composition of the present invention further contains 0.05 to 10 parts by mass of stearic acid as component (D) with respect to 100 parts by mass of component (A). When the content of the component (D) is less than 0.05 parts by mass, the adhesive rubber composition is easily attached to the mixer casing. On the other hand, when it exceeds 10 parts by mass, the tackiness and dynamic adhesiveness are lowered. From these viewpoints, the content of the component (D) is preferably 0.1 to 6 parts by mass, more preferably 0.1 to 3 parts by mass, and still more preferably 0 with respect to 100 parts by mass of the component (A). 0.5 to 3 parts by mass.
In addition, since it becomes easy to form a complex by adding the component (D), it tends to bleed out and the adhesiveness tends to decrease. However, this tendency can be reduced by using the component (E) later. It has been found that it can be reduced. From this viewpoint, when the component (E) is contained in the adhesive rubber composition of the present invention, the content of the component (C) with respect to 1 part by mass of the component (E) is preferably 0.05 to 10 parts by mass, More preferably, it is 0.1-7 mass parts, More preferably, it is good to set it as 0.5-7 mass parts.

((E) benzothiazole vulcanization accelerator)
The adhesive rubber composition of the present invention may further contain a benzothiazole vulcanization accelerator as the component (E). By including the component (E), the tackiness and adhesiveness can be enhanced. Specific examples of the benzothiazole vulcanization accelerator are shown below, but are not particularly limited thereto.

As the benzothiazole vulcanization accelerator, 2-mercaptobenzothiazole (MBT) is preferable from the viewpoints of tackiness and adhesiveness.
When the adhesive rubber composition of this invention contains (E) component, Preferably content of (E) component is 0.1-1 mass part with respect to 100 mass parts of (A) component, More preferably 0.3-1 mass part, More preferably, it is 0.3-0.7 mass part. If the content of the component (E) is 0.1 parts by mass or more with respect to 100 parts by mass of the component (A), the effect of improving tackiness and adhesiveness is sufficient, and if the content is 1 part by mass or less, storage There is little risk of vulcanization at times.

(Other ingredients)
The adhesive rubber composition of the present invention may contain (F) a reinforcing filler in addition to the components (A) to (E). Reinforcing fillers include carbon black, silica and inorganic fillers. Carbon black, silica, and inorganic filler may be used in combination, but it is usually preferable to use carbon black alone. When the adhesive rubber composition of the present invention contains the component (F), the content of the component (F) is preferably 60 parts by mass or less, more preferably 10 to 10 parts by mass with respect to 100 parts by mass of the component (A). 60 mass parts, More preferably, it is 20-60 mass parts.
Examples of the carbon black include channel black, furnace black, acetylene black, and thermal black depending on the production method, and any of them can be used. Furnace black is particularly preferable, and for example, SRF, GPF, FEF, HAF, ISAF, and SAF can be preferably used.

Examples of other components further include (G) an anti-aging agent. Examples of the anti-aging agent include amine-based anti-aging agents and phenol-based anti-aging agents. Examples of the amine anti-aging agent include 2,2,4-trimethyl-1,2-dihydroquinoline polymer, 6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline, diphenylamine and acetone. Amine-ketone-based anti-aging agents such as reactants; phenyl-1-naphthylamine, alkylated diphenylamine, octylated diphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, p- (p-toluenesulfonyl) Amido) diphenylamine, N, N′-di-2-naphthyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N- (1 , 3-Dimethylbutyl) -N′-phenyl-p-phenylenediamine, N-phenyl-N ′-(3 -Aromatic secondary amine type anti-aging agent such as -methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine. Examples of the phenolic antioxidant include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, mono (or di or tri) (α -Monophenol type anti-aging agents such as -methylbenzyl) phenol.
When the adhesive rubber composition of the present invention contains the component (G), the content of the component (G) is preferably 20 parts by mass or less, more preferably 10 parts by mass with respect to 100 parts by mass of the component (A). Or less.
In addition, the adhesive rubber composition of the present invention may contain zinc oxide, plasticizer, wax and the like. These contents are preferably 0.1 to 20 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the component (A).

The adhesive rubber composition of the present invention can be obtained by kneading the above components using a kneader such as a roll, an internal mixer, a Banbury mixer or the like.
The adhesive rubber composition of the present invention thus obtained has a Mooney viscosity at 130 ° C. of about 35 to 70, a curast t ₁₀ of about 1 to 5 minutes, and a t ₉₀ of about 3 to 10 minutes. The Mooney viscosity is a value measured in accordance with JIS K6300-1, preheated at 130 ° C. for 1 minute, and then measured for 4 minutes. Curast is defined in JIS K6300 “Physical test method for unvulcanized rubber”. A sample is pressurized with a measuring die of 155 ° C. and two sets of upper and lower circular dies, and continuously heated at an amplitude angle of ± 1 ° 100 cpm cycle. The torque generated on the shaft was measured, and the times t ₁₀ and t ₉₀ to reach 10% and 90% vulcanization amounts were measured.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited at all by these examples.
In addition, about the adhesive rubber composition obtained in each case, the adhesiveness test, the dynamic adhesiveness test, and the Mooney scorch test were done according to the following method, and also the adhesion degree to the mixer casing was investigated.

(1. Tackiness test)
An unvulcanized rubber sample shown in FIG. 1 was produced using the adhesive rubber composition produced in each example. The prepared sample was subjected to pressure at 25 ° C. with a press at a pressure of ² kg / cm ² for 5 seconds. The sample was subjected to a peel test in accordance with the “peeling test of cloth and vulcanized rubber” method of JIS-K6256, and the peel force was set to 100 in Example 3 to obtain a relative value.
As Reference Example 1, an unvulcanized rubber sample was prepared in the same manner as described above using the adhesive rubber composition shown in Table 1 below. On the side where the unvulcanized rubbers shown in FIG. 1 are in contact with each other, a “rubber cement” in which 80 parts by mass of toluene is mixed with 20 parts by mass of the compound shown in Table 1 below is naturally dried, and then unadded A test was conducted in the same manner using a sample obtained by pasting vulcanized rubber as a sample. The results are shown in Table 5.

＊１：天然ゴム、グレード；ＲＳＳ−３号
＊２：「ＳＢＲ１５００」、スチレン−ブタジエンゴム、ＪＳＲ株式会社製
＊３：「旭♯６０」、旭カーボン株式会社製
＊４：「ＭＸＳＴ１００」、ミヨシ油脂株式会社製
＊５：「ＡＮＴＩＧＥＮＥ（登録商標）６Ｃ」、住友化学株式会社製
＊６：３号亜鉛華、ハクスイテック株式会社製
＊７：「セイミサルファー」、日本乾留工業株式会社製
＊８：「ダイアナプロセスオイル ＡＨ−５８」、出光興産株式会社製
＊９：「ノクセラー（登録商標）ＣＺ」、大内新興化学工業株式会社製

* 1: Natural rubber, grade; RSS-3 * 2: "SBR1500", styrene-butadiene rubber, manufactured by JSR Corporation * 3: "Asahi # 60", manufactured by Asahi Carbon Corporation * 4: "MXST100", Miyoshi * 5: “ANTIGENE (registered trademark) 6C”, manufactured by Sumitomo Chemical Co., Ltd. * 6: No. 3 Zinc Hana, manufactured by Hakusui Tech Co., Ltd. * 7: “Seimi Sulfer”, manufactured by Nippon Kiln Kogyo Co., Ltd. * 8: “Diana Process Oil AH-58”, manufactured by Idemitsu Kosan Co., Ltd. * 9: “Noxeller (registered trademark) CZ”, manufactured by Ouchi Shinsei Chemical Co., Ltd.

(2. Dynamic adhesion test)
The blending of A rubber and B rubber shown in FIG. 2 is as shown in Table 2 below. A rubber is a rubber that has been vulcanized at 160 ° C. for 20 minutes, B rubber is an unvulcanized rubber, and an adhesive rubber is 0.5 mm thick made of the adhesive rubber composition produced in each example. After combining the unvulcanized rubber, a sample vulcanized at 140 ° C. for 30 minutes and punched into a dumbbell shape shown in FIG. 2 was used. The dumbbell-shaped sample is JIS K 6251 dumbbell-shaped No. 3 and has a thickness of 2.0 mm. Using this sample, a test was conducted in accordance with JIS K 6270 at a strain of 100% and a frequency of 5 Hz, and the number of times until breakage was determined with the value of Example 1 as 100, and a relative value was obtained.
In Reference Example 1, the adhesive rubber composition shown in Table 1 above was used as the adhesive rubber, and rubber cement (similar to that used in the adhesion test) was used for the surfaces of both A rubber and B rubber in contact with the adhesive rubber. ) And air-dried, and then dumbbell-shaped samples were produced in the same manner as above except that A rubber, adhesive rubber and B rubber were bonded together and vulcanized. The results are shown in Table 5.

＊１〜６、＊８、＊９：表１中のものと同じである。
＊７’：「金華印微粉硫黄」、１５０メッシュ、鶴見化学工業株式会社製

* 1-6, * 8, * 9: Same as those in Table 1.
* 7 ': "Jinhua stamp fine powder sulfur", 150 mesh, manufactured by Tsurumi Chemical Co., Ltd.

(3. Mooney scorch test)
Mooney scorch test in unvulcanized rubber physical testing method of JIS K 6300 the (t ₅ measured) were carried out at 125 ° C.. The relative value of the obtained t ₅ value was determined with the value of Example 3 as 100.
Further, as Reference Example 1, the Mooney scorch test was performed using a mixture of the same adhesive rubber composition and rubber cement used in the tack test. The results are shown in Table 5.

(4. Investigation of the degree of adhesion to the mixer casing)
Each component for the adhesive rubber composition was mixed and kneaded at a rotation speed of 50 rpm using a Banbury type kneader “MIXTRON BB-2 MIXER” manufactured by Kobe Steel Co., Ltd. When the display temperature reached 110 ° C., the adhesive rubber composition was discharged and evaluated according to the following evaluation criteria.
○: All the adhesive rubber composition was discharged within 1 minute.
Δ: It took more than 1 minute, but all the adhesive rubber composition was discharged.
X: Even if it took 3 minutes, the adhesive rubber composition adhered to the casing, and all was not discharged.
In addition, as Reference Example 1, a mixture of the same adhesive rubber composition and rubber cement as used in the tack test was used to investigate the degree of adhesion to the mixer casing. The results are shown in Table 5.

Examples 1 to 19, Comparative Examples 1 to 6 and Reference Example 1
Using the components and blending amounts described in Tables 3 and 4, kneaded at 130 ° C. using a Banbury type kneader “MIXTRON BB-2 MIXER” manufactured by Kobe Steel Co., Ltd. to prepare an adhesive rubber composition did. Tables 3 and 4 show the results of investigation on the degree of adhesion to the obtained adhesive rubber composition, tackiness test, dynamic adhesion test, Mooney scorch test, and mixer casing.
Further, as Reference Example 1, each test was performed as described above by using a conventional method in which an adhesive rubber composition and a rubber cement were used in combination. The results are shown in Table 5.

The annotations in Table 3 and Table 4 will be described below.
* 11: Natural rubber, grade; RSS-3 * 12: "SBR1500", styrene-butadiene rubber, manufactured by JSR Corporation * 13: "IR2200", isoprene rubber, manufactured by JSR Corporation * 14: "BR01", butadiene Rubber, manufactured by JSR Co., Ltd. * 15: “Seimi Sulfer”, manufactured by Nihon Kirin Kogyo Co., Ltd. * 16: “Kinka Stamp Fine Sulfur”, 150 mesh, manufactured by Tsurumi Chemical Co., Ltd. * 17: “ESCOREZ 1102”, Exxon Chemical Co., Ltd. * 18: "Accel M", 2-mercaptobenzothiazole, manufactured by Kawaguchi Chemical Co., Ltd. * 19: "Diana Process Oil AH-58", manufactured by Idemitsu Kosan Co., Ltd. * 20: "MXST100", manufactured by Miyoshi Oil & Fats Co., Ltd.

From Tables 3 and 4, the adhesive rubber composition of the present invention can strongly stick rubbers without using rubber cement, and has high adhesion after vulcanization without using rubber cement. became. Moreover, it turns out that it is hard to adhere to a mixer casing.
On the other hand, in Comparative Example 1 which did not contain the component (B), the dynamic adhesiveness was greatly reduced. In Comparative Example 1 in which soluble sulfur was used instead of the component (B), the dynamic adhesiveness was significantly lowered along with the tackiness. In Comparative Example 3 in which the content of the component (B) was small, the dynamic adhesiveness was lowered. In Comparative Example 4 in which the content of the component (B) was large, the tackiness decreased and the Mooney scorch time decreased. In Comparative Example 5 in which the content of natural rubber and / or isoprene rubber in the rubber component was less than 60% by mass, the tackiness and dynamic adhesiveness were greatly reduced. Further, in Comparative Example 6 in which the content of the component (C) was large, the dynamic adhesiveness was lowered, the Mooney scorch time was reduced, and the adhesion to the mixer casing was severe.

  The adhesive rubber composition of the present invention can strongly stick rubbers without using rubber cement, and has high adhesion after vulcanization without using rubber cement. Further, the adhesive rubber composition of the present invention is less likely to be vulcanized during storage, and further, when mixed with a mixer to obtain a composition, it is difficult to adhere to the mixer casing, resulting in high working efficiency. Useful. Such an adhesive rubber composition of the present invention can be used for endless joining and repair of various rubbers, and is particularly useful for endless joining and repair of conveyor belts.

Claims (3)

(A) 100 parts by mass of a rubber component containing 60% by mass or more of at least one selected from the group consisting of natural rubber and isoprene rubber;
(B) 2 to 4 parts by mass of sulfur containing 60% by mass or more of insoluble sulfur which is a component insoluble in carbon disulfide,
An adhesive rubber composition comprising (C) 5 to 15 parts by mass of a C5 petroleum resin, and (D) 0.05 to 10 parts by mass of stearic acid.   The adhesive rubber composition according to claim 1, further comprising (E) 0.1 to 1 part by mass of a benzothiazole vulcanization accelerator.   The adhesive rubber composition according to claim 1 or 2, which is used for a conveyor belt.

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