Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1988-08-26
1992-05-05
Teskin, Fred
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525191, 525211, C08C 4500, C08L 900
Patent
active
051108720
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to rubber compositions comprising rubbery polymers made up of ethylene and .alpha.-olefins and/or unconjugated dienes hereunder referred to typically as "EP" type rubbers, and selected cyclopentadiene resins. Such type of composition has improved roll retention and tack strength characteristics in an unvulcanized state, thus ensuring adequate processability and excellent quality of the EP rubber prior to and after vulcanization.
BACKGROUND ART
EP type rubbers, because of their superior resistance to ozone, to weathering and to heat, find extensive application to automotive parts, building components, industrial rubber products and the like. However, these rubbers tend to suffer from reduced roll retention and decreased tackiness prior to vulcanization, giving rise to processing problems.
By the term roll retention is meant the ability of an EP type rubber to adhere to the surface of a roll mill while being blended with additives. Insufficient roll retention contributes to laborious, time-consuming blending operation.
Tackiness is an adhesive property by which a rubber is bonded under mild pressure to a mating rubber or to a different material. Automobile tires and tubes are generally formed for instance by bonding rubber/rubber laminates into a desired shape which is subsequently vulcanized. Rubber laminates of poor tack strength are difficult to vulcanize while retaining the desired shape, and the resulting vulcanizate is susceptible to delamination.
To cope with these problems, a variety of tackifiers and processing aids have been proposed but with little success. Cumarone resins, terpene resins and aliphatic petroleum resins in common use as tackifiers would show no appreciable rise in tack strength. Extender oils if added in large amounts may improve tackiness to some extent, but would result in a vulcanizate being physically weak. Still much thus remains to be desired despite many attempts made with other tackifiers as disclosed for instance in Japanese Patent Publication No. 46-21897 and Japanese Patent Laid-Open Publication No. 51-87555.
The present invention seeks to provide an improved rubber composition which excels in roll retention and tack strength.
DISCLOSURE OF THE INVENTION
Through extensive research leading to the invention, the present inventors have discovered that rubber compositions of enhanced roll retention and tack strength characteristics can be obtained by the use of EP type rubbers combined with a selected class of cyclopentadiene resins.
According to the invention, there is provided a rubber composition comprising 100 parts by weight of a rubber made up of ethylene and an .alpha.-olefin and/or an unconjugated diene, and 0.5-30 parts by weight of at least one of the following polycyclopentadienes: (a) a cyclopentadiene resin derived by copolymerizing 100 parts by weight of a first component with 5-200 parts by weight of a second component, the first component being either one or both of a 5-membered, conjugated double bond-containing compound and its Diels-Alder adduct and represented by the formula ##STR2## where H is a hydrogen atom, R is a C.sub.1-3 alkyl group, m and n each are 0-6, and the sum of m and n is 6, and the second component being an unsaturated aromatic component having in the molecule a carbon double bond and a benzene nucleus; (b) a polar group-containing cyclopentadiene resin formed by copolymerizing 100 parts by weight of the first component with 1-200 parts by weight of a third component which is a compound having a polar group and a carbon double bond, the polar group being a hydroxyl, carboxyl, carboxylic anhydride, ester, nitrile or amide group; (c) a polar group-containing cyclopentadiene resin obtained by reacting 100 parts by weight of a polymer resulting from the homopolymerization of the first component with 1-200 parts by weight of the third component; and (d) a phenolic hydroxyl group-containing cyclopentadiene resin prepared by copolymerizing 100 parts by weight of the first component with 2-200 parts b
REFERENCES:
patent: 4129557 (1978-12-01), Kudo et al.
patent: 4785071 (1988-11-01), Kondo et al.
Hackh's Chemical Dictionary, 4th ed., J. Grant (ed.), McGraw-Hill Inc. N.Y., 248 (1969).
Kobayashi Yukio
Sasaki Makoto
Tsuchiya Shozo
Adams Bruce L.
Nippon Oil Co. Ltd.
Teskin Fred
Wilks Van C.
LandOfFree
Rubber composition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rubber composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rubber composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1412932