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
2000-05-08
2003-08-19
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S239000, C525S240000
Reexamination Certificate
active
06608142
ABSTRACT:
TECHNICAL FIELD
This invention relates to compositions of polyvinyl chloride resins and polyolefins that are essentially free of liquid plasticizers.
BACKGROUND
Various blends of polyvinyl chloride (PVC) resin are known. These blends, which are useful in numerous applications including wire and cable, medical devices, and automotive and appliance parts, often incorporate elastomers, e.g., nitrile rubber or flexible thermoplastics, e.g., polyurethane. Although blends containing these elastomers and thermoplastics exhibit enhanced physical properties, they also suffer from poor low temperature flexibility, inadequate heat resistance, poor weathering characteristics, mediocre processibility, and relative high cost of production.
SUMMARY
In general, the invention relates to compositions of polyvinyl chloride (PVC) resins and thermoplastic elastomer polyolefins that are essentially free of liquid plasticizers. These compositions possess good physical properties, including high degree of elongation, favorable low temperature properties, and good thermal resistance and oxygen barrier properties. Such compositions can be used in numerous applications such as components of wire and cable, medical devices, and parts for automotive and other appliances.
In one aspect, the invention features a composition containing a PVC resin, a thermoplastic elastomer polyolefin which is a metallocene-catalyzed reaction product of ethylene and an alpha-olefin monomer (i.e., an ethylene-alpha-olefin copolymer such as ethylene-1-octene copolymer or ethylene-1-butene copolymer), and a component selected from the group consisting of chlorinated polyethylene, polycaprolactone, and combinations thereof. The PVC composition is essentially free of liquid plasticizers (for example, less than about 0.01 parts, e.g., less than about 0.001 parts, based upon 100 parts of the PVC resin).
In another aspect, the invention features a composition containing a PVC resin, a polyolefin which is a metallocene-catalyzed reaction product of ethylene and an alpha-olefin monomer, and a component selected from the group consisting of chlorinated polyethylene, polycaprolactone, and combinations thereof. The composition is essentially free of liquid plasticizers, and has an unaged (or original) brittle point no greater than −30° C. and/or an elongation of at least 100%.
As used herein, a liquid plasticizer refers to a compound which, when added to a polymer, serves to soften the polymer. The compound is in the form of a liquid at ambient temperature. Examples of a liquid plasticizer include compounds such as phthalates (e.g., dioctyl, diisooctyl, or diheptylnonyl), and aliphatic ester adipates and sebacates (e.g., dioctyl adipate or sebacate).
Other features and advantages of the invention will be apparent from the following description of the preferred embodiments thereof, and from the claims.
DETAILED DESCRIPTION
A composition is provided that is essentially free of liquid plasticizers, and contains a PVC resin, a polyolefin which is a metallocene-catalyzed reaction product of ethylene and an alpha-olefin monomer, and a component selected from the group consisting of chlorinated polyethylene, polycaprolactone, and combinations thereof. The composition further optionally contains resins such as butyl rubber, ethylene-propylene-diene monomer rubber (EPDM), ethylene-propylene rubber (EPR), or combinations thereof, and/or additives such as lubricants, stabilizers, antioxidants, and fillers.
“Polyvinyl chloride” or “PVC,” as used herein, includes homopolymers of vinyl chloride, as well as polymerization products of vinyl chloride and one or more co-monomers. For example, the PVC resin can be a copolymer of vinyl chloride and ethylene, or a copolymer of vinyl chloride and propylene. The PVC resin can also be the polymerization product of vinyl chloride and an ester monomer having the formula H
2
C═C(R
1
)C(═O)OR
2
, where R
1
and R
2
are, independently, C
1-12
alkyl. An example of such a resin is a copolymer of a vinyl chloride monomer and a methyl methacrylate monomer. These resins may be used alone or in combination.
The compositions are essentially free of liquid plasticizers, e.g., phthalates, trimelletates, pyromelletates, azelates, adipates, and the like.
The compositions contain a thermoplastic elastomer polyolefin which is a metallocene-catalyzed reaction product of ethylene and an alpha-olefin monomer. Preferred polyolefins include a copolymer of ethylene and 1-octene that is a metallocene-catalyzed reaction product of these two monomers, available from DuPont-Dow Elastomers under the trade name ENGAGE (e.g., ENGAGE 8150, ENGAGE 8440, and ENGAGE 8452). Another example of such a thermoplastic elastomer polyolefin is a copolymer of ethylene and 1-butene, available from Exxon Chemicals under the trade name EXACT 3035.
Preferably, the compositions contain at least about 5 parts, and more preferably from about 15 parts to about 65 parts, of the polyolefin that is a metallocene-catalyzed reaction product of ethylene and an alpha-olefin monomer (based on 100 parts by weight of the PVC resin).
The compositions also contain a component selected from the group consisting of chlorinated polyethylene (CPE), polycaprolactone, and any combinations thereof. The component improves the compatibility of the PVC resin and the polyolefin, thereby imparting desired mechanical properties to the resulting compositions.
Preferably, the compositions contain at least 20 parts, and more preferably from about 50 parts to about 150 parts, of the just-mentioned component (based on 100 parts by weight of the PVC resin).
When CPE is present in the compositions, it is preferred that the compositions contain at least 10 parts, more preferably from about 20 parts to about 60 parts, of CPE (based on 100 parts by weight of the PVC resin), and that the CPE has a chlorine content of about 5% to about 50% by weight. It is also preferred that the CPE is the chlorinated product of a slurry process. The chlorination process generally decreases the crystallinity of the material; it is preferred that the CPE has a residual polyethylene crystallinity of at least about 0.5% (measured by differential scanning calorimetry). Preferred CPE are commercially available, for example, from Dow Chemical under the trade name TYRIN 3623A.
When polycaprolactone is present in the compositions, it is preferred that the compositions contain at least 10 parts, more preferably from about 20 parts to about 100 parts, of polycaprolactone (based on 100 parts by weight of the PVC resin). Preferably, polycaprolactone present in the compositions has a molecular weight ranging from about 10,000 to about 60,000. An example of a preferred polycaprolactone is commercially available from Solvay under the trade name CAPA 640.
The PVC compositions may further contain one or more elastomers other than the just-described metallocene-catalyzed reaction products of ethylene and an alpha-olefin monomer. Examples of such elastomers include homopolymers (e.g., polyethylene or polypropylene) and copolymers (e.g., a copolymer of ethylene and propylene (EP rubber), a copolymer of ethylene, propylene, and a non-conjugated diene monomer (EPDM), a copolymer of ethylene and an alpha-olefin having at least 4 carbons, ethylene-propylene rubber (EPR), and butyl rubber (i.e., polyisobutene copolymer)). The elastomers may be used alone or in combination.
Preferably, the PVC compositions contain butyl rubber. When butyl rubber is present in the compositions, it is preferred that the compositions contain at least 5 parts, more preferably from about 20 parts to about 75 parts, of butyl rubber (based on 100 parts by weight of the PVC resin). Butyl rubber, which can be chlorinated or brominated, are commercially available, for example, from Exxon Chemical under the trade name BUTYL 065.
The PVC compositions may also contain ingredients such as lubricants, stabilizers, antioxidants, and fillers. Examples of suitable lubricants include stearic acid, metal salts of stearic acid, wax, and polyethylene glycols.
Andries John
Brookman Robert S.
Saunders Keith G.
Weng Dexi
Bissett Melanie
Teknor Apex Company
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