Stock material or miscellaneous articles – Composite – Of polycarbonate
Reexamination Certificate
2002-02-08
2003-11-04
Boykin, Terressa M. (Department: 1711)
Stock material or miscellaneous articles
Composite
Of polycarbonate
C525S146000, C525S148000, C525S439000, C528S196000, C528S198000, C528S271000, C528S272000
Reexamination Certificate
active
06641920
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to multi-layer structures comprising a film, sheet or profile produced from specific blends of polycarbonates and polyesters, that is provided with an outer layer, on one or more sides, with a surface cap layer comprising a polycarbonate and an ultraviolet (UV) absorbing component.
BACKGROUND OF THE INVENTION
Certain blends of polycarbonates and copolyesters can be formed into films that are thermoformable without the necessity of drying the films prior to thermoforming. However, the films are subject to the effects of ultraviolet (UV) radiation.
It is accordingly an object of this invention to provide UV radiation protection to the film, sheet or profile formed from the blends of polycarbonates and copolyesters.
It is a further object of this invention to provide a surface functionality of a polycarbonate to the film, sheet or structure formed from the blends of polycarbonates and copolyesters.
It is a further object of this invention to provide a UV protected multi-layer structure that may be used as regrind.
It is a further object of this invention to provide a UV protected multi-layer structure that may be thermoformed without the need for pre-drying the structure and that will not result in the formation of blisters.
It is a further object of this invention to provide a UV protected multi-layer structure that has increased heat deflection temperature (HDT).
SUMMARY OF THE INVENTION
In accordance with the present invention, a multi-layered structure is prepared as follows. A film, sheet or profile is prepared from a blend or composition defined as follows:
The blend or composition comprises from about 15 to about 40 weight percent (%) polycarbonate and from about 60 to about 85 weight % copolyester. Any polycarbonate may be used. The specific copolyesters used are based on an acid component comprising terephthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, or mixtures thereof containing from 15 to about 35 mol percent (%) isophthalic acid and a glycol component comprising from about 80 to 100 mol % 1,4-cyclohexanedimethanol.
A UV protective layer, comprising at least one, or more, polycarbonate and at least one, or more, UV absorbing compound, is typically coextruded or laminated onto at least one side of the film, sheet or profile formed from the blend of polycarbonate and copolyester.
The UV protected multi-layer structures herein may be used for many applications, such as for skylights, signs, glazing, laminates, packaging food, clothing, pharmaceutical products, multi-wall sheets, and the like. Accordingly, the present invention is directed to articles of manufacture incorporating the multi-layered structures of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, a multi-layered structure is prepared as follows. A film, sheet or profile is prepared from a blend or composition defined as follows:
The blend or composition comprises from about 15 to about 40 weight percent (%) polycarbonate and from about 60 to about 85 weight % copolyester. Any polycarbonate may be used. The specific copolyesters used are based on an acid component comprising terephthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, or mixtures thereof containing from about 15 to about 35 mol (%) isophthalic acid and a glycol component comprising from about 80 to 100 mol % 1,4-cyclohexanedimethanol.
A UV protective layer, comprising at least one, or more, polycarbonate and at least one, or more, UV absorbing compound, is typically coextruded or laminated onto at least one side of the film, sheet or profile formed from the blend of polycarbonate and copolyester.
The UV protected multi-layer structures herein may be used for many applications, such as for skylights, signs, glazing, laminates, packaging food, clothing, pharmaceutical products, multi-wall sheets, and the like. Accordingly, the present invention is directed to articles of manufacture incorporating the multi-layered structures of the present invention.
In more detail, the blend or composition comprises at least one, or more, polycarbonate(s) and at least one, or more, of the specified copolyester(s). The amounts of components of all blends or compositions herein are provided in weight percent (%), based on the weight of the blend or composition.
The polycarbonate component of the blend or composition may be any polycarbonate. The polycarbonates suitable for use in the present invention are well known and are generally commercially available. The polycarbonates may be branched or linear. Suitable polycarbonates are exemplified, but not limited to, those described in U.S. Pat. Nos. 3,028,365; 3,334,154; 3,915,926; 4,897,453; 5,674,928; and 5,681,905, all of which are incorporated herein by reference. The polycarbonates may be prepared by a variety of conventional and well known processes which include trans-esterification, melt polymerization, interfacial polymerization, and the like. The polycarbonates are generally prepared by reacting a dihydric phenol with a carbonate precursor, such as phosgene. Suitable processes for preparing the polycarbonates of the present invention are described, for example, in U.S. Pat. Nos. 4,018,750; 4,123,436; and 3,153,008. Preferred polycarbonates for use in the present invention are aromatic polycarbonates, with aromatic polycarbonates based on bisphenol-A [2,2-bis(4-hydroxyphenyl)propane], such as are obtained by reacting bisphenol-A with phosgene, being more preferred. Diphenyl carbonate or dibutyl carbonate may be utilized in place of phosgene.
In the blend or composition, the polycarbonate is present in an amount ranging from about 15 to about 40 weight %, based on the weight of the total blend or composition, and the copolyester is present in an amount ranging from about 60 to about 85 weight %, both based on the weight of the total blend or composition. The polycarbonate is preferably present in an amount of about 20 to 28 weight percent and the copolyester is preferably present in an amount of about 80 to 72 weight percent, based on the weight of the total blend or composition.
The copolyester component of the blend or composition of the present invention is at least one, or more of poly(1,4-cyclohexylene-dimethylene terephthalate) (PCT), poly(1,4-cyclohexylenedimethylene naphthalenedicarboxylate) (PCN), poly(1,4-cyclohexylenedimethylene 1,4-cyclohexanedicarboxylate) (PCC) copolyesters, or mixtures thereof, containing about 15 to about 35 mol % isophthalic acid with a preferred amount being from 20 to about 30 mol % isophthalic acid. The copolyester comprises an acid component comprising from about 65 to about 85 mol percent of a dicarboxylic acid selected from terephthalic acid, naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid or mixtures thereof; from about 15 to about 35 mol percent isophthalic acid; and from 0 to about 20 mol percent of other dicarboxylic acid units. The copolyester comprises a glycol component of about 80 to 100 mol percent 1,4-cyclohexanedimethanol (CHDM) and from 0 to about 20 mol percent other glycol units. The total dicarboxylic acid units is equal to 100 mol percent, the total glycol units is equal to 100 mol percent and the total polyester units is equal to 200 mol percent.
The CHDM and 1,4-cyclohexanedicarboxylic acid moieties used to prepare the copolyesters can be trans, cis or trans/cis mixtures of isomers. Any of the naphthalenedicarboxylic acid isomers or mixtures of isomers can be used with the 1,4-, 1,5-, 2,6-, and 2,7-isomers being preferred.
The other dicarboxylic acid(s) that can be used herein in amounts of from 0 to about 20 mol percent have from about 4 to about 40 carbon atoms. Exemplary of the other dicarboxylic acids suitable for use herein are sulfoisophthalic, sulfodibenzoic, succinic, glutaric, adipic, sebacic, suberic, dimer, dodecanedioic, and the like, or mixtures thereof.
The other glycol unit(s) that can be used herein in amounts of from 0 to about 20 mol percent contain from about 3 to a
Conn Roy Lee
Willham John Edward Christopher
Williams James Carl
Boshears B. J.
Boykin Terressa M.
Eastman Chemical Company
Graves Bernie
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