Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2002-06-10
2004-10-26
Mulcahy, Peter D. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S399000
Reexamination Certificate
active
06809138
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an adhesion accelerator for enhancing the adhesive strength between rubber and metal. In particular, this invention relates to an adhesion accelerator for enhancing the adhesive strength of rubber to steel cords. In addition, the present invention also relates to a rubber composition containing the above adhesion accelerator.
2. Description of the Prior Art
Heretofore, in order to improve the adhesive strength of natural or synthetic rubber to steel cords used as a reinforcement for a radial tire or a belt of a belt conveyer, there have been used, as an adhesion accelerator, cobalt-containing metal organic compounds such as cobalt stearate, cobalt naphthenate, cobalt-boron complex, etc. Although these cobalt-containing metal organic compounds have a high vulcanization accelerating ability, the presence of cobalt in rubber lowers the storage stability. Besides cobalt-containing organic compounds, some other metal organic compounds have also been investigated. In fact, many patents disclose the use of some specific metal organic compounds as adhesive strength improving agents. For instance, some organic acid cobalt salts are disclosed in the following patents. U.S. Pat. No. 1,919,718 discloses cobalt acetate and cobalt salts of low molecular fatty acids, particularly a cobalt stearate. U.S. Pat. No. 2,912,355 discloses cobalt oleate and cobalt citrate. U.K. patent 1,169,366 discloses cobalt linoleate and cobalt resinate. U.S. Pat. No. 4,076,668 discloses cobalt salts of naphthenic acid, octylic acid, tall oil acid, etc. Japanese Patent Application Laid-Open No. 61-60743 discloses cobalt propionate, calcium propionate, magnesium propionate, nickel propionate, zinc propionate, etc. Japanese Patent Application Laid-Open No. 6-65142 discloses a metallic soap having a structure of naphthalene or biphenyl. Japanese Patent Application Laid-Open No. 60-15444 and Japanese Patent Application Laid-open No. 60-158230 disclose cobalt borate and the like. Japanese Patent Application Laid-Open No. 60-199643 discloses a metal salt of thiosulfuric acid ester. Japanese Patent Application Laid-Open No. 59-207949 and Japanese Patent Application Laid-Open No. 6-329838 disclose a metallic soap having a specific ratio of cobalt to nickel, as an adhesion improving material. Japanese Patent Application Laid-Open No. 6-329840 discloses a metallic soap having a specific ratio of cobalt to zinc, as an adhesion improving material. Although the above substances have a good adhesive property in a specific aspect, they still fail to show a well-balanced adhesive strength as a whole.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved adhesion accelerator having an excellent adhesive property well comparable with or far superior to that of a cobalt organic compound and having an improved stability for storing. It is another object of the present invention to provide a rubber composition containing such an adhesion accelerator.
The present inventors have found that the purposes of the invention can be achieved by adding a nickel organic compound and a zinc organic compound, in place of cobalt organic compounds. Namely, the present inventors have found that adding a nickel organic compound and a zinc organic compound in combination can produce an excellent adhesive property as compared with the case using a cobalt organic compound alone, and that an adhesion accelerator containing the above two compounds can produce an excellent adhesive property during a process of vulcanization at a high temperature and provide an excellent storing stability to the rubber kneaded therewith.
Namely, the present invention is directed to:
(1) An adhesion accelerator for improving the bonding of vulcanized rubber to metal, in which the improvement is characterized in the adhesion accelerator comprising:
at least one nickel organic compound selected from the group consisting of Ni-containing soaps having carboxylic acid moieties each having 6 to 30 carbon atoms in its main chain, or a mixture thereof, an organic boron complex containing Ni bonded to a carboxylic acid moiety having 6 to 30 carbon atoms in its main chain, and Ni-acetyl acetonate, and
at least one zinc organic compound selected from the group consisting of Zn-containing soaps having carboxylic acid moieties each having 6 to 30 carbon atoms in its main chain, or a mixture thereof, an organic boron complex containing Zn bonded to a carboxylic acid moiety having 6 to 30 carbon atoms in its main chain, and Zn-acetyl acetonate,
the at least one nickel organic compound and the at least one zinc organic compound being blended together to have a Ni/Zn weight ratio of from 0.01 to 20 in the adhesion accelerator.
(2) The adhesion accelerator for bonding rubber to metal as described in the above (1), in which the nickel organic compound and the zinc organic compound are metallic soaps.
(3) The adhesion accelerator for bonding rubber to metal as described in the above (1), in which the weight ratio of Ni/Zn is from 0.05 to 10.
(4) A rubber composition for forming a vulcanized rubber having an improved adhesion to metal comprising a rubber component, sulfur and the adhesion accelerator as set forth in any of the above (1) to (3), the sulfur being present in an amount of 3 to 8 parts by weight and the adhesion accelerator being present in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the rubber component.
(5) A method of improving the bonding of vulcanized rubber to metal, in which the improvement is characterized in the adhesion accelerator being added to a rubber component and 3 to 8 parts by weight sulfur, based on 100 parts by weight of the rubber component, prior to the vulcanization thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As set forth above, the present invention can provide synergistic improvements in the adhesive property and storage stability of a rubber composition due to the use of a combination of a nickel organic compound and a zinc organic compound.
The nickel organic compounds used in the present invention are as mentioned above and include nickel-containing compounds such as metallic soaps of a carboxylic acid. Examples of such compounds are nickel naphthenate, nickel neodecanate, nickel stearate, nickel-containing organic boron complex and nickel acetylacetonate.
The zinc organic compounds used in the present invention are as mentioned above and include zinc-containing compounds such as metallic soaps of a carboxylic acid. Examples of such compounds are zinc naphthenate, zinc neodecanate, zinc stearate, zinc-containing organic boron complex and zinc acetylacetonate.
Carboxylic acids used to form metallic soaps are natural or synthetic saturated or unsaturated carboxylic acids having 6 to 30 carbons in their main chains, or a mixture thereof. The carbon of a carboxylic group is excluded from the above-mentioned number of carbons. More specific examples are caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, iso-stearic acid, arachic acid, behenic acid, oleic acid, linoleic acid, linolenic acid, ricinoleic acid, 12-hydroxy stearic acid, dimeric acid, tall oil acid, naphthenate, neodecanoic acid, resin acid. Alternatively, there may be exemplified natural fatty acids, such as fish oil hardened fatty acid or beef tallow hardened fatty acid containing as its main component one or more of the above-listed acids. Therefore, as the metallic soaps obtained by using these carboxylic acids, nickel naphthenate and zinc neodecanate may be mentioned as preferable examples.
Further, in the present invention, metallic soaps as mentioned above may be used in the form of a mixed soap thereof and such a mixed soap may be prepared by a conventional process, such as a double decomposition process with alkali metallic soaps as intermediate products, a direct reaction process involving a direct reaction between metallic compounds and carboxylic acids, etc.
When a nickel
Iida Kazunori
Imori Toru
Flynn ,Thiel, Boutell & Tanis, P.C.
Mulcahy Peter D.
Nikko Materials Co., Ltd.
LandOfFree
Adhesion accelerator for bonding rubber to metal and rubber... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Adhesion accelerator for bonding rubber to metal and rubber..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Adhesion accelerator for bonding rubber to metal and rubber... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3297930