JP2006328335A - Rubber composition for directly vulcanizing and bonding rubber to metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for directly vulcanizing and bonding a peroxide-crosslinkable rubber to a metal. <P>SOLUTION: The bonding of the rubber to the metal is carried out simultaneously with a crosslinking reaction by bringing a rubber composition containing 1-30 pts.wt. peroxide, 0.1-5 pts.wt. 2,4,6-trimercapto-s-triazine and 0.5-30 pts.wt. 1,3,5-triacryloylhexahydro-s-triazine based on 100 pts.wt. rubber crosslinkable by the peroxide into contact with the metal of a bonding object. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to adhesion between rubber and metal. More specifically, the present invention relates to direct vulcanization adhesion in which rubber is subjected to a crosslinking reaction while rubber and metal are brought into contact with each other, and at the same time, rubber and metal are bonded.

Direct vulcanization bonding between rubber and metal has been put to practical use with unsaturated rubber capable of sulfur vulcanization. For example, in the case of tire steel belts, a brass-plated steel cord and a rubber composition containing sulfur are contacted. At the same time as vulcanization, copper sulfide is formed on the metal surface, and rubber and metal are bonded via sulfur (see, for example, Non-Patent Document 1). Further, the direct vulcanization adhesion between unsaturated rubber and metal in a peroxide crosslinking system is achieved by internally adding a peroxide and triazine thiol with a nitrile butadiene rubber (see, for example, Non-Patent Document 2). ). Peroxide-cured rubber-to-metal direct vulcanization bonds do not generate or reduce volatile gases that can corrode the deposit metal or other nearby metals during or after the vulcanization reaction. There are advantages over direct vulcanization adhesion using sulfur vulcanization systems.
"Direct adhesion between rubber and metal-Focusing on the brass plating method-Industrial Chemical Journal, Vol. 73, No. 1, 1970, p.50" “Cross-bonding of metal and unsaturated rubber in peroxide cross-linking system, Journal of Japan Rubber Association, Vol. 65, No. 3, 1992, p.181”

Direct vulcanization adhesion between unsaturated rubber and metal in peroxide crosslinking system is achieved by adding triazine thiol internally, but rubber with relatively low unsaturation, for example ethylene propylene non-conjugated diene terpolymer With (EPDM) or the like, sufficient adhesive force cannot be obtained. In addition, when a rubber is crosslinked with a peroxide crosslinking system, a compound having a thiol group such as triazine thiol inhibits peroxide crosslinking and lowers the physical properties of the crosslinked rubber.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention. That is, 1 to 30 parts by weight of peroxide, 0.3 to 5.0 parts by weight of 2,4,6-trimercapto-s-triazine and 1,3 parts per 100 parts by weight of rubber that can be crosslinked with peroxide. , 5-triacryloylhexahydro-s-triazine A rubber composition containing 0.5 to 20 parts by weight is used to solve the above problems and complete the present invention by performing direct vulcanization adhesion with a metal. It came.

1,3,5-triacryloylhexahydro-s-triazine (hereinafter referred to as TAF) functions as a so-called crosslinking aid that improves the physical properties of the crosslinked rubber bonded to the rubber by peroxide. On the other hand, it easily reacts and binds to a compound having a thiol group such as 2,4,6-trimercapto-s-triazine (hereinafter referred to as TSH). When three specific substances consisting of peroxide, TAF and TSH are present in the rubber, the rubber cross-linking and the rubber and metal are not affected even if the rubber has a relatively low degree of unsaturation. It was possible to perform bonding at the same time.

Hereinafter, the present invention will be described in more detail with specific embodiments. In the present invention, the peroxide-crosslinkable rubber is a rubber containing a general diene component, such as natural isoprene rubber (NR), synthetic isoprene rubber (IR), butadiene rubber (BR), and styrene-butadiene copolymer rubber. (SBR), acrylonitrile butadiene copolymer rubber (NBR), ethylene propylene non-conjugated diene terpolymer (EPDM), and the like may be mentioned, and these may be single or mixed. The peroxide involved in crosslinking in the present invention is not particularly limited as long as it is a peroxide that is generally used as a rubber crosslinking agent, and the optimum peroxide for the rubber should be selected. Can do. Preferably, a peroxide having a half-life of 10 hours and a temperature of 80 ° C. or higher is ideal for simultaneous rubber cross-linking and rubber-metal adhesion. For example, 1,1-di-t-butyl Peroxy-3,3,5-trimethylcyclohexane, 2,5-di-methyl-2,5-di-benzoylperoxyhexane, n-butyl-4,4-di-t-butylperoxyvalerate, dicumylper Oxide, t-butylperoxybenzoate, di-t-butylperoxy-diisopropylbenzene, t-butylcumyl peroxide, 2,5-di-methyl-2,5-di-t-butylperoxyhexane, di- Examples thereof include t-butyl peroxide and 2,5-di-methyl-2,5-di-t-butylperoxyhexyne-3. The amount of the peroxide added may be arbitrarily selected within the range of 1 to 15 parts by weight with respect to 100 parts by weight of the rubber crosslinkable with peroxide, that is, the crosslinking efficiency of the peroxide with respect to each rubber. . For this purpose, among the triazine compounds having a plurality of thiol groups, TSH is specified as TSH, and the addition amount is preferably 0.3 to 5.0 parts by weight with respect to 100 parts by weight of rubber that can be crosslinked with peroxide. If the amount is less than parts by weight, the adhesive strength is insufficient. If the amount exceeds 5.0 parts by weight, the crosslinking is significantly inhibited. The amount of TAF added is preferably in the range of 0.5 to 20 parts by weight with respect to 100 parts by weight of the rubber crosslinkable with peroxide, and is preferably added at least twice the amount of TSH. In addition, metal oxides that react with TSH to form metal salts, for example, metal oxides such as zinc oxide, tend to inhibit the adhesion between rubber and metal, and are therefore limited in use. In addition, substances having a thiol group other than TSH may react with TAF and tend to inhibit the adhesion between rubber and metal, so that its use is limited. With respect to the other compounding agents, there are no limitations as long as they are general in obtaining a peroxide-crosslinked rubber.

Hereinafter, although an example is given and it explains still more concretely, of course, the present invention is not limited at all by the example. Table 1 shows the contents of Comparative Examples 1 to 7 and Example 1. The rubber compound shown in Table 1 is obtained by processing with a processing machine generally used for kneading rubber, such as a Banbury mixer, a kneader, an open roll, and the like.
Table 1 shows the rheometer measurement results of Comparative Examples 1 to 7 and Example 1. Compared to Comparative Example-1, the maximum elastic torque (MH) of Comparative Example-5 to which TSH was added was decreased, indicating that TSH inhibited peroxide crosslinking. In Comparative Examples 6 and 7, although TAC and TAIC, which are crosslinking aids, are added to suppress a decrease in maximum elastic torque (MH) due to TSH, it cannot be said to be sufficient. On the other hand, compared to Comparative Example 1, Example 1 has an improved maximum elastic torque (MH) despite the addition of TSH that inhibits peroxide crosslinking, and TAF crosslinking in the presence of TSH. The effect as an auxiliary agent is seen.
Table 1 shows the results of physical properties of general vulcanized rubbers of Comparative Examples 1 to 7 and Example 1. The rubber hardness (Hs) and stress at 100% elongation (M100) of Comparative Example-5 to which TSH is added are lower than those of Comparative Example-1, and TSH inhibits peroxide crosslinking. I understand. In Comparative Example-6 and Comparative Example-7, TAC and TAIC, which are crosslinking assistants, were added to suppress the decrease in stress (M100) at 100% elongation due to TSH, but it was not sufficient. Almost no improvement is seen in the hardness (Hs). On the other hand, compared with Comparative Example 1, Example 1 has improved rubber hardness (Hs) despite the addition of TSH that inhibits peroxide crosslinking, and stress at 100% elongation (M100). ) Is small, and the effect of TAF as a crosslinking aid in the presence of TSH is observed. Furthermore, it is a preferable result that the heat aging resistance of Example 1 is superior to any of Comparative Examples 1 to 6.
Table 1 shows the results of the adhesion / peeling test for rubber and metal of Comparative Examples 1 to 7 and Example 1. Direct vulcanization adhesion between rubber and metal uses brass plate C2801 (copper content: 59-62%) as a target metal, and laminates each rubber compound and brass plate of Comparative Examples 1-7 and Example 1, Using a predetermined mold, press vulcanization was performed at 170 ° C. for 10 minutes to prepare a sample for a peel test. The peel test was based on a 90 degree peel test for metal pieces and rubber according to JISK6256. In Comparative Examples 1 to 4, since TSH is not present in the compounding, adhesion between rubber and metal hardly occurs. On the other hand, in Comparative Example 5 in which TSH was added, adhesion between rubber and metal occurred, and Comparative Example 6 in which TAC as a crosslinking aid was used in combination and Comparative Example 7 in which TAIC was used together were in adhesion between rubber and metal. There is an improvement in sex. However, in any case, peeling occurs at the interface between the rubber and the metal, and it cannot be said that the adhesive strength is sufficient. On the other hand, in Example 1, peeling did not occur at the interface between the rubber and the metal, and the rubber layer was destroyed first. Therefore, it was confirmed that the adhesive strength is at least 17 times that of Comparative Example 5.

Claims (1)

1 to 30 parts by weight of peroxide, 0.1 to 5 parts by weight of 2,4,6-trimercapto-s-triazine and 1,3,5-tril to 100 parts by weight of rubber crosslinkable with peroxide A rubber composition containing 0.5 to 30 parts by weight of acryloylhexahydro-s-triazine.