Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1995-12-11
1999-02-16
Henderson, Christopher
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525189, 5253326, C08L 8100, C08L 1900
Patent
active
058721886
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a vulcanized rubber composition having improved physical and mechanical properties. More particularly, it relates to a rubber composition which is vulcanized in the presence of an anti-reversion coagent and a sulfide resin. The invention also relates to a vulcanization process which is carried out in the presence of an anti-reversion coagent and a sulfide resin and the use of an anti-reversion coagent in combination with a sulfide resin in the vulcanization of rubber. Finally, the invention also relates to rubber products comprising rubber vulcanized in the presence of an anti-reversion coagent and a sulfide resin.
In the tire and belt industries, among others, a better resistance to reversion is being demanded. This curing characteristic results in improved mechanical and heat resistance properties.
It has been observed that the sulfur-vulcanization of a composition comprising a rubber and an anti-reversion coagent comprising at least two groups selected from citraconimide and/or itaconimide groups results in a substantial reduction in the reversion of sulfur-vulcanized rubber compositions. This concept is generally disclosed in PCT patent applications WO 92/07904 and 92/07828.
However, these sulfur-vulcanized rubber products still require improvement in physical and mechanical properties, such as tensile properties, heat resistance, and dynamic properties.
It is therefore the primary object of the present invention to improve upon the compositions disclosed by WO 92/07904 and 92/07828 by providing a sulfide resin which will solve the problems associated with these compositions. It has been found that the presence of a sulfide resin during vulcanization of rubber with an anti-reversion coagent results in improved physical and mechanical properties.
For example, the heat resistance of the rubber is improved by the presence of sulfide resin during vulcanization. Also, a decrease of loss compliance (J") is established. This property leads to tires with a reduced rolling resistance. No detrimental effects on the properties have been observed as a result of the use of a sulfide resin in rubber compositions.
Accordingly, the present invention relates to a vulcanized rubber composition which comprises the vulcanization reaction product of a composition containing at least: donor to provide the equivalent of 0 to 25 parts by weight of sulfur; comprising at least two groups selected from citraconimide and/or itaconimide groups; and wherein Z.sub.1, Z.sub.2, and Z.sub.3 are independently selected from linear or branched C.sub.1-18 alkylene groups, C.sub.2-18 alkenylene groups, C.sub.2-18 alkynylene groups, C.sub.6-18 arylene groups, C.sub.7-30 alkarylene groups, C.sub.7-30 aralkylene groups, C.sub.3-18 cycloalkylene groups, optionally containing one or more hetero atoms; optionally substituted with hydroxy, amino, thiol, and halogen groups; each x is independently selected from an integer of 1 to 10; and n is an integer from 1 to 100.
Each sulfide link S.sub.x in the above-mentioned general formula may be a linear linkage of sulfur atoms, such as --S--, --S--S--, --S--S--S--, etc., but also ##STR1## etc.
In a preferred embodiment the sulfide resin is of the following formula (I) ##STR2## wherein R1, R2, and R3 are independently selected from linear or branched C.sub.1-10 alkyl groups, each x is independently selected from an integer of 1 to 10, and n is an integer from 1 to 100. R.sub.1, R.sub.2, and R.sub.3 are preferably tertiary alkyl groups, meta- or para-substituted on the aromatic group with respect to the hydroxy group. More preferably, R.sub.1, R.sub.2, and R.sub.3 are para-substituted with respect to the hydroxy group. The sulfide resin is then a para-tertiary alkyl phenol sulfide.
In U.S. Pat. No. 2,422,156 the preparation of para-tertiary alkyl phenol sulfides is described starting from para-tertiary alkyl phenol and a sulfide compound, such as sulfur dichloride or sulfur monochloride. The symbol x in formula (I) depends upon how much sulfur is introduced in the reaction. Using
REFERENCES:
patent: 2422156 (1947-06-01), Wolf et al.
patent: 3968062 (1976-07-01), Ecsedy
patent: 3974163 (1976-08-01), Yaucher et al.
patent: 3992362 (1976-11-01), Martin
patent: 4308180 (1981-12-01), Okamura
patent: 4873290 (1989-10-01), Allen et al.
Alkylphenol Sulfides as Vulcanizing Agents, G. M. Wolf, et al. Sharles Chemicals, Inc., Wyandote, Michigan, pp. 1157-1166 Nov. 1946.
Hoffman Rubber Technology Handbook, Hanser Publishers, pp. 136-138, 1989.
Hoffman Rubber Technology Handbook, Chapter 4, Rubber Chemicals and Additives pp. 217-353, Hanser Publishers, 1989.
The Synthesis of Bisitaconamic Acids and Isomeric Bisimide Monomers, Journal of Polymer Science: Polymer Chemistry Edition, vol. 20, 233-239 (1982).
The Synthesis of Biscitraconimides and Polybiscitraconimides, Anthony V. Galanti, Journal of Polymer Science: Polymer Chemistry Edition, vol. 19, 451-475 (1981).
Synthesis of N-Substitued Bisitaconimide Monomers for Use as Thermosetting Polyimide Resins, S.L. Hartford, et al., Journal of Polymer Science: Polymer Chemistry Edition, vol. 16 137-153 (1978).
Datta Rabindra Nath
de Hoog Arie Jacob
Wilbrink Johannes Hermanus
Akzo Nobel nv
Henderson Christopher
Mancini Ralph J.
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