Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1992-10-19
1994-03-08
Jagannathan, Vasu S.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C08L 6300
Patent
active
052928101
DESCRIPTION:
BRIEF SUMMARY
FIELD OF ART
This invention relates to a thermoplastic elastomer composition having high thermal resistance.
BACKGROUND ART
The thermoplastic elastomers (hereinafter abbreviated as TPE) which are industrially used at present can be roughly divided into two types: TPE comprising a block copolymer composed of soft segments and hard segments and TPE, called elastomer alloy, comprising a partially crosslinked rubber and a plastic phase-separated therefrom. As the former type, there are known, for instance, the block copolymers called polyester elastomers consisting of an aliphatic polyether portion such as polytetramethylene glycol and a polyester portion such as polyethylene terephthalate and polybutylene terephthalate, and the block copolymers called polyamide elastomers consisting of an aliphatic polyether portion and a polyamide portion such as polydodecanolactum. As the latter type, there are known, for example, the elastomer alloys comprising a dynamically vulcanized alloy of polypropylene and an ethylenepropylene-diene terpolymer.
Also, European Patent Laid-Open No. 0287233 discloses a polymer solution for coating using a copolymer having an aromatic polyester as branch polymer, namely a copolymer having an aromatic polymer covalently bonded to an acrylic resin or polyester resin, said polymer solution being characterized by being capable of forming a coat with high hardness. However, this European patent is silent on thermoplastic resins and TPE.
It is to be noted that with TPE's comprising a block copolymer composed of soft and hard segments, it is merely possible to obtain relatively hard elastomer having a Shore hardness (D scale) of about 40 or greater. Also, these TPE's take a large compression set and are not so high in thermal resistance.
On the other hand, the elastomer alloys, although capable of forming the soft elastomers having a Shore Scale A hardness of about 30, are rather poor in thermal resistance.
The object of the present invention is to provide a resin composition useful as a thermoplastic elastomer with excellent thermal resistance.
DISCLOSURE OF THE INVENTION
In view of these circumstances, the present inventors have pursued further studies on the subject matter and, as a result, found out a composition containing a thermoplastic graft copolymer comprising a polymer having a glass transition temperature of 10.degree. C. or below as main chain and a specific aromatic oligomer as side chain, and an olefinic polymer. It was further found that said composition had the excellent properties as a thermoplastic elastomer. These findings have led to the attainment of the present invention.
Thus, the present invention pertains to a thermoplastic elastomer composition containing a thermoplastic graft copolymer comprising a polymer having a glass transition temperature of 10.degree. C. or below as main chain and an aromatic oligomer having a flow temperature defined below of 100.degree. C. or above as side chain, and an olefinic polymer.
Flow temperature: the temperature at which the oligomer shows a melt viscosity of 48,000 poises when the oligomer is melted by heating at a rate of 4.degree. C./min and extruded from a nozzle of 1 mm in inner diameter and 10 mm in length under a load of 100 kg/cm.sup.2.
The main chain (backbone polymer) constituting the graft copolymer of this invention is the one having a glass transition temperature of 10.degree. C. or below, preferably 0.degree. C. or below, more preferably -10.degree. C. or below. The "glass transition temperature" referred to herein means the secondary transition point at which absorption of heat is observed at the heating rate of 10.degree. C./min in a differential scanning calorimeter (DSC). If the glass transition temperature (which may hereinafter be abbreviated at Tg) of said main chain (backbone polymer) exceeds 10.degree. C., the produced thermoplastic elastomer composition of this invention may fail to show rubber elasticity in the working temperature range above normal temperature.
As preferred examples of the main chain
REFERENCES:
patent: 5171765 (1992-12-01), Jones et al.
patent: 5187224 (1993-02-01), Hamanaka et al.
Hikasa Tadashi
Manabe Kenji
Niwano Masahiro
Jagannathan Vasu S.
Sumitomo Chemical Company Limited
LandOfFree
Thermoplastic elastomer 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 Thermoplastic elastomer composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic elastomer composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-154100