Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1992-06-05
1994-12-27
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...
5253303, 5253306, 5253308, 5253317, 5253328, 5253329, 5253331, 5253332, 5253337, 5253339, 525343, 525386, C08F 800
Patent
active
053767306
DESCRIPTION:
BRIEF SUMMARY
FIELD OF ART
This invention relates to a thermoplastic graft copolymer that can be used as a thermoplastic elastomer, especially the one required to have high thermal resistance for specific uses such as heat-resisting hoses, sealants and automobile materials, and a process for preparing such copolymer.
BACKGROUND ART
Presently, the industrially used thermoplastic elastomers (hereinafter abbreviated as TPE) are roughly divided in two types: TPE comprising a block copolymer consisting of soft segments and hard segments and TPE comprising a partially crosslinked rubber called elastomer alloy and a plastic phase-separated therefrom. As the former type of TPE, there are known a block copolymer consisting of segments of an aliphatic polyether such as polytetramethylene glycol and segments of a polyester such as polyethylene terephthalate and polybutylene terephthalate, which is called polyester elastomer, and a block copolymer consisting of segments of aliphatic polyether and segments of a polyamide such as polydodecanolactum, which is called polyamide elastomer. As the latter type of TPE, there is known, for instance, an elastomer alloy yielded from dynamic vulcanization of an alloy of polypropylene and ethylene-propylene-diene terpolymer.
European Patent laid-Open Specification 0287233 discloses preparation of a polymer solution for coating by using a copolymer having an aromatic polyester in the side chain, namely a copolymer having an aromatic polyester covalently bonded to an acrylic or polyester resin, and it is claimed that this polymer solution is capable of forming a coating film with high hardness. This patent specification, however, is silent on thermoplastic resin and TPE.
The TPE's comprising the block copolymers consisting of soft and hard segments are the relatively hard elastomers which are over 40 in D scale of Shore hardness. Also, these TPE's are subject to large compression set and not so high in thermal resistance.
On the other hand, the elastomer alloys are capable of forming soft elastomers of down to about 30 in A scale of Shore hardness, but they are poor in thermal resistance.
DISCLOSURE OF THE INVENTION
In view of these circumstances, the present inventors have pursued further studies and, as a result, discovered a thermoplastic graft copolymer comprising, as main chain, a polymer having a glass transition temperature of 10.degree. C. or below and, as side chain, an aromatic oligomer having a flow temperature of 100.degree. C. or above, and a process for preparing such graft copolymer. It was further found that said graft copolymer has the excellent properties as a thermoplastic elastomer, and these findings have led to the attainment of the present invention.
Further, as a result of strenuous studies, the present inventors unveiled a graft copolymer comprising as backbone a polymer having a glass transition temperature of 10.degree. C. or below and as side chain an aromatic oligomer with a flow temperature of 100.degree. C. or above, characterized in that the polymer having a glass transition temperature of 10.degree. C. or below is partially crosslinked and that the obtained graft copolymer is capable of melt flow. It was also found that said graft copolymer has the excellent properties as a thermoplastic elastomer, and based on these findings, the present invention was completed.
The thermoplastic graft copolymer according to this invention is defined to be the one whose compression set after 22 hours at 70.degree. C. (JIS K 6301) is less than 90%, Shore D hardness is below 50 and permanent set at 23.degree. C. is less than 50%. It is especially preferred that ultimate elongation at 23.degree. C. is greater than 100%.
The thermoplastic graft copolymer of this invention is further characterized in that it is insoluble in the good solvents of the polymer having a glass transition temperature of 10.degree. C. or below constituting said graft copolymer.
Also, in the thermoplastic graft copolymer of this invention, the polymer having a glass transition temperature of 10.degree. C
REFERENCES:
patent: 4217430 (1980-08-01), Starkweather, Jr. et al.
Manabe Kenji
Murase Ichiki
Nakayama Nobuko
Namioka Makoto
Niwano Masahiro
Lipman Bernard
Sumitomo Chemical Company Limited
LandOfFree
Thermoplastic graft copolymer and process for preparing the same 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 graft copolymer and process for preparing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic graft copolymer and process for preparing the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-920354