Stock material or miscellaneous articles – Composite – Of polyamide
Reexamination Certificate
1998-04-21
2001-12-04
Gallagher, John J. (Department: 1733)
Stock material or miscellaneous articles
Composite
Of polyamide
C156S273700, C525S093000, C525S179000, C525S184000
Reexamination Certificate
active
06326084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for high frequency welding of non-polar thermoplastic elastomer compositions comprising a suitable modifier. Furthermore, the present invention relates to shaped articles obtainable by the method according to the present invention.
Conventional non-polar thermoplastic elastomer compositions comprising a thermoplastic polyolefin homopolymer or copolymer and an olefinic rubber which is fully crosslinked, partially crosslinked or not crosslinked and/or block-copolymer of styrene/conjugated diene/styrene and/or its hydrogenated derivative, optionally in the presence of common additives can only be adhered together by using adhesives or must be heat welded by the hot air or hot plate method. These conventional methods present several disadvantages such as, in the adhesive method, the need to modify the adhering surface, (for instance, by priming, corona treatment, etching, etc.), selection of the suitable adhesive, etc., and in the hot air and hot plate method, the relatively slow speed, the difficulty to control the temperature to obtain adequate welding without burning the surface.
High frequency welding is, however, not feasible with those thermoplastic elastomers. However, there is a need in the industry to make those thermoplastic elastomers accessible to the high frequency welding method.
The high frequency welding method is a well-known, well-established method of heat-sealing materials together, which method can easily be carried out. Said method is used in many sections of the industry such as inflatables (boats, containers, life-rafts, oil-booms, etc.), automotive, automotive ancillaries, office and school equipment, tenting, tarpaulins, packaging and for many other purposes, wherever proper adhesion is desired.
2. Description of the Related Art
U.S. Pat. No.4,728,566 pertains to a composite article comprising a polymer foam having HF-bonded thereto at least one surface layer, wherein the HF-bonding is effected by a layer of HF-bondable polymer film between said foam and said surface layer, said HF-bondable polymer film comprising a carbon monoxide-containing olefin interpolymer and said polymer foam being selected from the group consisting of various foamed polymers. The surface layer is selected from the group comprising polymers, fabrics, leather, cellulosic products, wood, vitreous materials, metal foils, paper and foams and the HF-bondable polymer film comprises at least one of ECO, ECOAA, ECOMAA and ECOVA.
U.S. Pat. No.2,667,437 discloses a method to heat-weld two non-polar, unmodified thermoplastics by exposing them to a pair of hot electrodes which are covered with a fixed conductive polymer.
U.S. Pat. No.4,268,388 pertains to almost the same welding-method as disclosed in U.S. Pat. No.2,667,437.
U.S. Pat. No.3,336,173 discloses the addition of a polyamide to non-polar thermoplastics in order to obtain a HF-weldable product without taking into consideration the very poor properties of such a blend due to the lack of compatibility between the non-polar thermoplastic and the polar polyamide.
EP-A-0,028,106 discloses the use of a special bituminous petroleum derivative as a HF-welding promotor in chlorinated PE/chlorosulfonated PE.
The available prior art does not suggest how non-polar thermoplastic elastomers could be welded by the high frequency welding method.
SUMMARY OF THE INVENTION
It has now surprisingly been found that non-polar thermo-plastic elastomers can be welded together by conventional high frequency welding methods after adding to said non-polar thermoplastic elastomer composition an effective amount of a compatible, polar modifier.
The term “compatible” means that the modifier has certain interactions with the polymer-matrix in order to maintain the overall physical properties of the polymer, i.e., the thermoplastic elastomer.
The thermoplastic elastomer may be in the form of any shaped article, such as films, sheets, boards, extruded articles injection or blow-molded parts, etc.
In detail, the present invention pertains to a method of high frequency welding of non-polar thermoplastic elastomers characterized in that the non-polar thermoplastic elastomer comprises as the polar modifier
(i) a copolymer obtainable by condensation reaction of
about 10 to about 90 weight % of a functionalized polymer with
about 90 to about 10 weight % of a polyamide, based on the total weight of functionalized polymer and polyamide, or
(ii) a functionalized polymer and a polyamide in the amounts defined under (i) or
(iii) a mixture of (i) and (ii).
It is preferred that the functionalized polymer contains no less than about 0.3 weight %, based on the total weight of the functionalized polymer, of at least one functional group-containing monomer.
It is preferred to add as an effective amount at least 3 weight parts of (i), (ii) or (iii), per 100 weight parts of the non-polar thermoplastic elastomer composition. More preferably at least 7 weight parts of (i), (ii) or (iii) are added. For most purposes the addition of up to 60 weight parts, more preferably up to 40 weight parts of (i), (ii) or (iii), per 100 weight parts of the non-polar thermoplastic elastomer is sufficient.
The non-polar thermoplastic elastomer is preferably selected from
(A)
(a) a thermoplastic polyolefin homopolymer or copolymer, and
(b) an olefinic rubber which is fully cross-linked, partially crosslinked or not crosslinked, and optionally
(c) common additives;
(B)
(a) a block-copolymer of styrene/conjugated diene/styrene and/or its hydrogenated derivative, optionally compounded with
(b) a thermoplastic polyolefin homopolymer or copolymer and/or
(c) common additives and
(C) any blend of (A) and (B).
In terms of the present invention the terms “non-polar thermoplastic elastomer” or “non-polar thermoplastic elastomer composition” means the thermoplastic elastomeric polymeric composition including optional additives.
Specifically, the present invention relates to a method of high frequency welding of an article or articles of a non-polar thermoplastic elastomer composition comprising
(A)
(a) a thermoplastic polyolefin homopolymer or copolymer, and
(b) an olefinic rubber which is fully cross-linked, partially crosslinked or not crosslinked, and optionally
(c) common additives;
(B)
(a) a block-copolymer of styrene/conjugated diene/styrene and/or its hydrogenated derivative, optionally compounded with
(b) a thermoplastic polyolefin homopolymer or copolymer and/or
(c) common additives and
(C) any blend of (A) and (B)
characterized in that at least 3 parts by weight of a polar compatible additive selected from
(i) a copolymer obtainable by condensation reaction of
about 10 to about 90 weight % of a functionalized polymer with
about 90 to about 10 weight % of a polyamide, based on the total weight of functionalized polymer and polyamide, or
(ii) a functionalized polymer and a polyamide in the amounts defined under (i) or
(iii) a mixture of (i) and (ii),
are added to 100 weight parts of (A), (B) or (C), under the proviso that the functionalized polymer contains no less than about 0.3 weight %, based on the total weight of the functionalized polymer, of at least one functional group-containing monomer.
The preferred amounts of (i), (ii) and (iii) in the nonpolar thermoplastic elastomer (A), (B) or (C) are mentioned above.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
I. Thermoplastic Elastomers
(i) Thermoplastic Elastomer (A)
Polyolefin:
Polyolefins suitable for use in the compositions (A), (B) or (C) of the invention include thermoplastic, crystalline polyolefin homopolymers and copolymers. They are desirably prepared from monoolefin monomers having 2 to 7 carbon atoms, such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-pentene, 4-methyl1-pentene, 5-methyl-1-hexene, mixtures thereof and copolymers thereof with (meth)acrylates and/or vinyl acetates. Preferred, however, are monomers having 3 to 6 carbon atoms, with propylene being preferred. As used in the specification and claims t
Horrion Jacques
Issum Ernst Van
Ouhadi Trazollah
Advanced Elastomer Systems L.P.
Gallagher John J.
Skinner William A.
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