Stock material or miscellaneous articles – Structurally defined web or sheet – Continuous and nonuniform or irregular surface on layer or...
Reexamination Certificate
1998-10-08
2001-04-17
Dawson, Robert (Department: 1712)
Stock material or miscellaneous articles
Structurally defined web or sheet
Continuous and nonuniform or irregular surface on layer or...
C428S521000, C428S522000, C428S904000, C264S175000, C525S095000, C525S097000, C525S098000, C525S055000, C525S191000, C525S208000, C525S221000, C525S222000
Reexamination Certificate
active
06217982
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to thermoplastic polymer alloy compositions which exhibit excellent low temperature properties coupled with heat and scuff resistance and furthermore can be processed by calendering.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 5,206,294, which is incorporated herein by reference, describes thermoplastic polymer alloy compositions (hereinafter referred to as “ETP-TPO's”) that fulfilled a need in the art, especially in the automotive field, for a material which combines the low and high temperature resistance properties of plasticized PVC, can be recycled easily, and exhibits scuff resistance and softness equal or superior to that of plasticized PVC. These ETP-TPO's have particular utility in automobile instrument panel skins since they provide excellent definition and grain retention on thermoforming, which is the most common method of forming such skins. These compositions also work very well in extrusion, typically used to prepare the embossed films used in the thermoforming step.
It is desirable to have an ETP-TPO that processes well by calendering because many commercial films used to prepare instrument panel skins are prepared by calendering. The ETP-TPO of U.S. Pat. No. 5,206,294, however, does not calender well exhibiting, for example, behavior such as sticking to the rolls or splitting between two rolls.
SUMMARY OF THE INVENTION
The present invention provides a calenderable ETP-TPO film (one that processes well by calendering), calendered sheet made therefrom and uses for such calenderable film and calendered sheet. The film and sheet may be a free-standing material or part of a laminated structure. It may be filled or unfilled. It may be embossed or non-embossed. It is useful in automotive and non-automotive applications including essentially all applications where flexible vinyl sheet has been or can be used.
The calenderable ETP-TPO of the present invention comprises
(a) thermoplastic alloy composition comprising a melt blend of
i) 10-40 wt. % polypropylene,
ii) 15-55 wt. % uncrosslinked ethylene propylene copolymer rubber,
iii) 20-60 wt. % of an ionomeric copolymer of ethylene, an alpha,beta-unsaturated C
3
-C
8
carboxylic acid, and optionally one or more softening comonomers copolymerizable with ethylene, and
iv) 1-5 wt. % of a copolymer of ethylene and glycidyl acrylate or glycidyl methacrylate, and
(b) 1-15 parts by weight per hundred parts of the thermoplastic alloy composition of an ethylene/alkyl (meth)acrylate copolymer.
DETAILED DESCRIPTION OF THE INVENTION
To provide an ETP-TPO with desired processing behavior on a mill or calender, about 1 to about 15 parts of an ethylene/alkyl (meth)acrylate copolymer is added to 100 parts by weight of a thermoplastic alloy composition comprising a melt blend of the following components (weight percents based on the total of the four components):
i) about 10 to about 40 percent by weight (wt. %), preferably about 15 to about 30 wt. %, polypropylene,
ii) about 15 to about 55 wt. %, preferably about 35 to about 50 wt. %, uncrosslinked ethylene propylene copolymer rubber,
iii) about 20 to about 60 wt. %, preferably about 25 to about 35 wt. %, ionomeric copolymer of ethylene and an alpha,beta-unsaturated C
3
-C
8
carboxylic acid, and optionally one or more softening comonomers copolymerizable with ethylene, and
iv) about 1 to about 5 wt. %, preferably about 2 to about 3 wt. %, copolymer of ethylene and glycidyl acrylate or glycidyl methacrylate.
The thermoplastic alloy compositions are generally prepared by melt blending the polymeric components under high shear conditions, for example in an extruder. The various ingredients may first be combined with one another e.g., in a pellet blend, or they may be combined with one another via simultaneous or separate metering of the various components. They may also be divided and blended in one or more passes into separate sections of the mixing equipment.
The ethylene/alkyl (meth)acrylate copolymer can be added to thermoplastic alloy composition either in the mixing step used to prepare the thermoplastic alloy composition or in a later melt-mixing step in an extruder, Banbury mixer, mill, or other mixing device.
The resultant compositions may be formed into calenderable films and calendered to make calendered sheets. The film and sheet is useful as free-standing material or as part of a laminated structure. The sheet may be embossed with a grain pattern. Such embossed sheet has excellent grain retention and thus has particular use in simulated leather applications and in instrument panel skins and door skins for automobiles. Fillers useful in filed applications include flame-retardant fillers such as calcium carbonate, mica, talc and glass. Filler levels can range from 0 to 80%. Due to its improved damage and penetration resistance, it has utility in roofing membranes and geomembranes.
Automotive uses include skins for instrument panels and for other locations such as door panels, simulated leather coverings, headliners, mats, and other grained and non-grained applications where flexible vinyl sheet has been used. Non-automotive uses include flooring systems and tiles, simulated leather coverings and other grained covering materials for furniture for example, geomembranes, and single-ply roofing material. The film and sheet are particularly useful in the form of a soft bottom layer of non-automotive flooring systems and tile. In those cases where the formulation is used as a layer in a multilayer structure, it would normally be adhered to the other layers by a tie layer except in those cases where the other layers are polypropylene based and an adhesion could be achieved by coextrusion or co-lamination. Thickness of the sheet can range from 0.1 to 2 mm.
The components employed in the present invention are as follows:
Polypropylene
The polypropylene component preferably employed is crystalline polypropylene and is intended to include, in addition to the homopolymer, those polymers that also contain minor amounts, usually not greater than 15 weight percent, of other alpha-olefins, e.g. those containing 2-8 carbon atoms, such as ethylene, butene, octene, etc. The polypropylene polymers useful in this invention have melt indices in the range of from about 0.07-80 dg/minute.
Uncrosslinked Ethylene Propylene Copolymer
The uncrosslinked ethylene/propylene copolymer rubber may be a polymer with two or more monomers but preferably is a terpolymer such as an ethylene/propylene
onconjugated diene copolymer or ethylene/propylene/ethylidene norbornene (EPDM). The nonconjugated dienes can contain from 6-22 carbon atoms having at least one readily polymerizable double bond. The uncrosslinked ethylene/propylene copolymer rubber contains about 60-80 weight percent, usually about 65-75 weight percent ethylene. The amount of nonconjugated diene is generally from about 1-7 weight percent, usually 2-5 weight percent.
EPDM copolymers that are especially preferred are ethylene/propylene/1,4-hexadiene, ethylene/propylene/dicyclopentadiene, ethylene/propylene
orbornene, ethylene/propylene/methylene-2-norbornene, and ethylene/propylene/1,4-hexadiene
orbornadiene copolymers. It is important that the ethylene propylene copolymer rubber be non-crosslinked because this imparts enhanced scuff resistance to the polymer alloys.
The EPDM copolymers (copolymers being polymers with two or more monomers) can be made using metallocene technology or non-metallocene processes well known in the art.
Ionomeric Copolymer
The ionomeric copolymer preferably employed is of ethylene, an unsaturated C
3
-C
8
carboxylic acid, and optionally one or more softening comonomers copolymerizable with ethylene. Acrylic and methacrylic acids are preferred acid comonomers. The softening comonomer can be an alkyl acrylate selected from the group consisting of n-propyl-, iso-butyl-, n-butyl-, n-octyl-, 2-ethylhexyl-, and 2-methoxyethyl-acrylates. The preferred alkyl acrylates are isobutyl-, n-butyl-, 2-ethylhexyl-, and 2-methoxyethyl-acrylates. The softening comonomer can also be an a
Dawson Robert
E. I. Du Pont de Nemours and Company
Peng Kuo-Liang
LandOfFree
Thermoplastic polymer alloy 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 polymer alloy composition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic polymer alloy composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2477638