Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1987-06-03
1991-03-12
Lipman, Bernard
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
524556, 5253306, 525369, C08F 844
Patent
active
049994042
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to an ionomer resin which is modified by additionally neutralizing with magnesium free carboxyl groups in an ionomer resin which has been neutralized with sodium.
2. Background Art
Ionomer resins are polymers having ion crosslinking in their chemical constitution. The ionomer resins are generally used for cover material for rubber articles, wrapping material, the sole of ski boots, car bumpers and the like, because of the excellent toughness and high resilience exhibited thereby.
The ionomer resins may be industrially prepared by a solution method (see Japanese Patent Publication (examined) Nos. 6810/1964 and 31556/1974). Japanese Patent Publication (examined) Nos. 15769/1967 and 38441/1983 also disclose a method using an extruder. In the above mentioned methods for preparing the ionomer resins, a copolymer of an .alpha.-olefin with an .alpha.,.beta.-ethylenically unsaturated carboxylic acid or an ester thereof is neutralized with a metal ion, such as sodium ion, zinc ion and the like.
The ionomer resin neutralized with a sodium ion (hereinafter referred to as "sodium neutralized ionomer resin") is superior to the zinc or magnesium neutralized ionomer resin in rebound properties, but has poor durability at a low temperature, which brings about cracking at a temperature of less than -5 .degree. C. In order to avoid the above defects, a method is proposed wherein the sodium neutralized ionomer resin is blended with the zinc neutralized ionomer resin. However, since the type of the ionomer resin to be blended is very limited, it is difficult to apply the product to a wide variety of products. Another ionomer resin containing both zinc ion and magnesium ion is proposed in Japanese Patent Publication (examined) No. 38441/1983. This ionomer resin has excellent durability at a low temperature, but has poor rebound properties. This ionomer resin is prepared by using a combination of a water-insoluble metal compound, such as zinc oxide, magnesium oxide, magnesium hydroxide and the like, with a volatile organic acid salt, such as zinc acetate, magnesium formate and the like. The volatile organic acid salt, however, corrodes the screw of an extruder and therefore the method is not preferred in an industrial application.
U.S. Pat. No. 4,526,375 discloses a method in which a sodium neutralized ionomer resin is further neutralized with magnesium oxide. The ionomer resin prepared by this method has fairly good physical properties, such as durability at a low temperature. In the process of preparing the ionomer resin, magnesium oxide remains in the obtained ionomer resin without participating in the neutralizing reaction. The nonreacted magnesium oxide is reacted with the ionomer resin when the resin is heated to an elevated temperature in the preparation of the final product. Reaction water is also evolved during the reaction and results in the poor durability of the final product. In order to avoid the defects, it is required to complete the reaction in the preparation of the ionomer resin and it takes a long time.
DISCLOSURE OF INVENTION
The inventors of the present invention have found a new preparation of an ionomer resin. The preparing process is easily carried out using a screw-type extruder and provides an ionomer resin having excellent durability at low temperature.
Thus, the present invention provides an ionomer resin prepared by additionally neutralizing 2 to 30% of the free carboxyl groups of a sodium neutralized ionomer resin with magnesium hydroxide.
The sodium neutralized ionomer resin employed in the present invention can be a thermoplastic resin prepared by copolymerizing 96 to 70% by weight of a monoolefin with 4 to 30% by weight of an unsaturated mono or dicarboxylic acid having 3 to 8 carbon atoms or an ester thereof (% is based on total weight of monomer), and neutralizing with sodium.
The sodium neutralized ionomer resins are available from Mitsui Du Pont Polychemical Company as HI-MILAN, for example, HI-MILAN 1601, 1605 and 1707.
Neutr
REFERENCES:
patent: 4526375 (1985-07-01), Nakade
"Fibres, Films, Plastics and Rubber", p. 19, Butterworth, 1975.
"Encyclopedia of Polymer Science and Technology", pp. 384 and 413, published by Interscience, 1968.
Lipman Bernard
Sumitomo Rubber Industries Ltd.
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