Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1995-06-02
2001-10-30
Russel, Jeffrey E. (Department: 1653)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C428S625000, C525S332700, C525S347000, C525S375000
Reexamination Certificate
active
06310144
ABSTRACT:
The present invention relates to a rubber article which is reinforced with a reinforcing material such as an organic fiber cord or a steel cord and can be used for automobile tires, conveyor belts, hoses and the like. The invention also relates to the production of the rubber article and further to a rubber composition suitable for coating an organic fiber cord as well as to another rubber composition suitable for coating a steel cord.
Organic fiber cords such as polyester, polyamide and aramid, or steel cords, particularly plated steel cords, such as brass-plated ones and zinc-plated ones are generally and widely used as a reinforcing material for rubber articles including automobile tires, conveyor belts, hoses and the like in order to improve and maintain strength and durability characteristics of the articles.
Of the organic fiber cords, polyester fibers are excellent in thermal resistance and fatigue resistance as well as in dimensional stability, and rubber tires formed by using the polyester fibers have such characteristics as large transverse stiffness and good steering stability. Thus, the polyester fibers are widely used in many rubber articles including rubber tires for automobiles.
Nevertheless, the polyester fibers have a problem in that the adhesion thereof to a coating rubber composition is poor. Accordingly there have been adopted some measures including a method of pretreating the polyester fibers with an adhesive such as resorcin or a resorcinolic resin, a method of incorporating such an adhesive into rubber during processing, and others. Although the use of the adhesive increases initial adhesiveness between the rubber and the polyester fibers, it causes the polyester cord itself to be thermally degraded, and further causes the rubber to be poor in thermal resistance and flex cracking resistance.
Besides, in order to improve the adhesiveness between a steel cord and coating rubber comprising natural rubber or synthetic rubber, there has hitherto been known a method of incorporating sulfur and an organic acid cobalt salt such as cobalt naphthenate into the rubber. Although the use of such a rubber composition for coating the steel cord increases the initial adhesiveness between the rubber and the steel cord, it deteriorates thermal resistance and flex cracking resistance of the rubber due to the incorporation of the organic acid cobalt salt.
On the other hand, there is known a method for improving the thermal resistance and flex cracking resistance of the rubber by incorporating any of various amine type antidegradants. The amine type antidegradants known for that purpose include, for example, N-isopropyl-N′-phenyl-p-diaminobenzene, N-(1,3-dimethylbutyl)-N′-phenyl-p-diaminobenzene, N,N′-diphenyl-p-diaminobenzene, N,N′-ditolyl-p-diaminobenzene, a condensation product of acetone and diphenylamine, a 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and the like.
However, when rubber is blended with such a conventional antidegradant and subjected to adhesion to organic fibers, the resulting rubber articles have some problems in that they are insufficient in antidegradation properties such as thermal resistance, and also in that the incorporation of the antidegradant adversely affects the adhesion properties to cause insufficiency in initial adhesiveness between the rubber and the organic fibers and cause deterioration of adhesiveness after thermal aging. Due to such problems, the antidegradants are much restricted in their kinds and loading amounts, and hence it is not able to fully satisfy both the requirements, i.e. the adhesion properties of the rubber to the polyester cord and the thermal resistance of the rubber.
When rubber is blended with the conventional antidegradant and subjected to adhesion to a steel cord, the resulting rubber articles have some problems in that they are insufficient in antidegradation properties such as thermal resistance and flex cracking resistance, and also in that the incorporation of the antidegradant adversely affects adhesiveness between the rubber and the steel cord, especially adhesion properties after thermal aging in the moist state.
Under such circumstances, the present inventors have made intensive research to solve the defects in the conventionally known antidegradants, and resultantly have found that blending a certain base rubber with a specific amount of a 2,2,4-trimethyl-1,2-dihydroquinoline polymer having particular formation improves adhesiveness between the rubber and a reinforcing material and further improves the thermal resistance of the rubber, thereby accomplishing the present invention.
Thus the invention provides a reinforced rubber article which comprises a rubber composition comprising 100 parts by weight of a base rubber selected from natural rubber and diene rubber, and 0.5 to 5 parts by weight of a 2,2,4-trimethyl-1,2-dihydroquinoline polymer having a primary amine content of not more than 1% by weight, a monomer content of not more than 3% by weight and a dimer content of at least 30% by weight; and a reinforcing material present in contact with the rubber composition; wherein the rubber composition is vulcanized in contact with the reinforcing material.
The invention also provides a method for producing a reinforced rubber article by blending 100 parts by weight of a base rubber selected from natural rubber and diene rubber with 0.5 to 5 parts by weight of a 2,2,4-trimethyl-1,2-dihydroquinoline polymer having a primary amine content of not more than 1% by weight, a monomer content of not more than 3% by weight and a dimer content of at least 30% by weight, and vulcanizing the resulting rubber composition in contact with a reinforcing material.
Incorporation of such a 2,2,4-trimethyl-1,2-dihydroquinoline polymer having particular formation into the rubber in a specific amount improves the adhesiveness of the rubber not only to polyester fibers but also to other organic fibers such as polyamide fibers and aramid fibers, and resultantly produces rubber articles having excellent thermal resistance with holding high adhesion properties between the rubber and the organic fibers.
When the 2,2,4-trimethyl-1,2-dihydroquinoline polymer is applied to a system for adhering rubber to an organic fiber cord, it is preferred to treat the organic fiber cord with a resorcinolic adhesive before embedding the cord into rubber or to additionally incorporate a resorcinolic adhesive into the rubber.
Thus the invention further provides a rubber composition comprising a base rubber selected from natural rubber and diene rubber and, based on 100 parts by weight of the base rubber, 0.5 to 8 parts by weight of a resorcinolic adhesive, and 0.5 to 5 parts by weight of a 2,2,4-trimethyl-1,2-dihydroquinoline polymer having a primary amine content of not more than 1% by weight, a monomer content of not more than 3% by weight and a dimer content of at least 30% by weight.
When the 2,2,4-trimethyl-1,2-dihydroquinoline polymer is applied to a system for adhering rubber to a steel cord, it is preferred to additionally use an organic acid cobalt salt and sulfur in combination. Incorporation of the organic acid cobalt salt, the sulfur and the 2,2,4-trimethyl-1,2-dihydroquinoline polymer having particular formation into the rubber each in specific amounts achieves improvements in adhesion properties between the rubber and the steel cord, especially inhibits deterioration in adhesiveness after thermal aging in the moist state, and further improves thermal resistance and flex cracking resistance of the rubber.
Thus the invention still further provides a rubber composition comprising a base rubber selected from natural rubber and diene rubber and, based on 100 parts by weight of the base rubber, 0.1 to 1 part by weight, as cobalt, of an organic acid cobalt salt, 2 to 10 parts by weight of sulfur, and 0.5 to 5 parts by weight of a 2,2,4-trimethyl-1,2-dihydroquinoline polymer having a primary amine content of not more than 1% by weight, a monomer content of not more than 3% by weight and a dimer content of at least 30% by
Inui Naoki
Nagasaki Hideo
Yamaguchi Tetsuo
Russel Jeffrey E.
Stevens Davis Miller & Mosher
Sumitomo Chemical Company Limited
LandOfFree
Reinforced rubber article, production thereof 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 Reinforced rubber article, production thereof and rubber..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reinforced rubber article, production thereof and rubber... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2606451