Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-06-19
2004-10-26
Lipman, Bernard (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S376000
Reexamination Certificate
active
06809157
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermoplastic polymer capable of repeatedly reformation of crosslinking and dissociation of crosslinkage with temperature, a method for producing the same, and a composition using the same.
The present invention also relates to a thermoplastic elastomer composition capable of repeatedly reformation of crosslinking and dissociation of crosslinking with temperature.
2. Description of the Related Arts
In recent years, reusage of waste materials is desired in view of environmental protection and resource saving. Vulcanized rubbers have stable three-dimensional networks in which polymer chain and vulcanizing agent are covalently bonded, and therefore show very strong strength, but are difficult to re-mold due to strongly covalent bond crosslinking. On the other hand, thermoplastic elastomers utilizing physical crosslinking state do not require complicated vulcanization and molding steps including pre-molding and the like, and therefore can easily be molded by heat melting.
Thermoplastic elastomer comprising a resin component and a rubber component, in which a crystal resin component forms a hard segment which serves as crosslinking point of a three-dimensional structure at room temperature to thereby prevent thermoplastic deformation of a rubber component (soft segment) whereby the thermoplastic elastomer plastically deforms by softening or fusion of the resin component with rising a temperature, is known as the representative example of such thermoplastic elastomers. However, such type of thermoplastic elastomers are liable to decrease rubber elasticity because of containing a resin component. For this reason, materials that do not contain a resin component and can impart thermoplasticity are demanded.
To solve the above problem, the present inventors previously proposed that an elastomer composition comprising an elastomer having a reaction site capable of forming hydrogen bonds and a compound having a reaction site capable of forming hydrogen bond together with the reaction site of the elastomer can repeats formation of crosslinking and dissociation of crosslinking by temperature difference utilizing hydrogen bond (JP-A-11-209524). Further, the same applicant as the present application proposed a hydrogen-bonding thermoplastic elastomer comprising an elastomeric polymer having a carbonyl-containing group and a heterocyclic amine-containing group in side chains, which is expected to have the similar effect in JP-A-2000-169527 (publication date: Jun. 20, 2000). JP-A-8-239583 describes organic polymers having a carbonyl-containing group and a nitrogen-containing heterocycle-containing group in side chains, wherein the nitrogen-containing heterocycle-containing ring-containing group is bonded to the main chain directly or through an organic group at a 2-position counted from nitrogen atom. Those elastomer compositions or organic polymers can sufficiently show melt flowability at a molding temperature of a thermoplastic resin such as olefin-based resin without modification, have excellent mechanical strength (breaking strength) at low temperature by the formation of crosslinking, and can repeatedly reformation of crosslinking and dissociation of crosslinking (softening).
Thermoplastic elastomers having such properties have very high value on industrial utilization and also very high value on environmental protection are expected for use as a material having further high crosslinking strength and having excellent recycle property, showing no change in physical properties even if formation of crosslinking and dissociation of crosslinking are repeated.
SUMMARY OF THE INVENTION
A first object of the present invention is to provide a thermoplastic polymer that sufficiently shows melt flowability at a molding temperature of ordinary thermoplastic resins, forms a stable crosslinking structure at room temperature, has rubber elasticity, and is capable of repeatedly rehardening and fluidization by altering the temperature, a method for producing the same, and a composition using the same.
By the way, the conventional thermoplastic elastomers described above have not been sufficient in shape retention when load is applied thereto in physical properties. Further, organic polymers described in JP-A-8-239583 have had the problems such that when a thermoplastic elastomer is used as a main chain, hardness is very small, and the properties are insufficient in using as an elastic material, such as using as a rubber material.
Accordingly, a second object of the present invention is to provide a thermoplastic elastomer composition which has a sufficient hardness in using as an elastic material and improved shape retention rate (compression set) without losing excellent recycle property and is capable of repeatedly rehardening and fluidization by altering the temperature.
As a result of extensive investigations to achieve the first object, the present inventors have found that when an elastomeric polymer is used as a main chain and a carbonyl-containing group and a nitrogen-containing five-membered heterocycle-containing group are contained in side chains, tensile strength under crosslinking is very high, further having the rubber elasticity, and capable of being easily softened approximately at 120° C. and even when formation of crossliking and dissociation of crosslinking are repeatedly conducted, physical properties do not decrease, making it possible to impart recycle property. The present invention has been completed based on this finding. It has also found that when an elastomeric polymer having a diene moiety of 5 mol % or less, such as EPM, EBM or EPDM; and a butyl rubber or a halogenated butyl rubber is used as the elastomeric polymer forming the main chain, and an elastomeric polymer having a carbonyl-containing group and a nitrogen-containing heterocycle-containing group in a specific proportion in side chains is used, excellent mechanical strength and recycle property can be imparted even if the nitrogen-containing heterocycle-containing group is not a five-membered ring regardless of the number of ring member of the heterocycle-containing group. The present invention has also be completed based on this finding. The term “mol %” used herein means a value on the basis of a monomer unit forming a polymer.
That is, a first aspect of the present invention provides a thermoplastic polymer having a carbonyl-containing group and a nitrogen-containing five-membered heterocycle-containing group in side chains.
A second aspect of the present invention provides a thermoplastic polymer having an elastomer as a main chain, in which a diene moiety is 5mol % or less, and a carbonyl-containing group and a nitrogen-containing heterocycle-containing group in side chains, wherein the proportion of side chain moiety is 0.1 to 50 mol % with respect to 100 mol % of the main chain moiety.
A third aspect of the present invention provides a thermoplastic polymer having an ethylene-propylene copolymer (EPM), an ethylene-butene copolymer (EBM) or an ethylene-propylene-diene copolymer (EPDM) as a main chain, and a carbonyl-containing group and a nitrogen-containing heterocycle-containing group in side chains, wherein the proportion of the side chain moiety is 0.1 to 50 mol % with respect to 100 mol % of the main chain moiety.
A fourth aspect of the present invention provides a thermoplastic polymer having a butyl rubber or a halogenated butyl rubber as a main chain, and a carbonyl-containing group and a nitrogen-containing heterocycle-containing group in side chains, wherein the proportion of the side chain moiety is 0.1 to 50 mol % with respect to 100 mol % of the main chain moiety.
In the second, third and fourth aspects, the nitrogen-containing heterocycle is preferably a five-membered ring or a six-membered ring.
In the first, second, third and fourth aspects, the carbonyl-containing group is preferably at least one member selected from the group consisting of amide, ester, imide and carboxy groups.
Further, the side chain pre
Ashiura Makoto
Chino Keisuke
Ikawa Masahiro
Kawazura Tetsuji
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Lipman Bernard
The Yokohama Rubber Co. Ltd.
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