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
1994-05-31
2001-06-26
Woodward, Ana (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...
C525S436000
Reexamination Certificate
active
06252011
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to polymer blends and, more particularly, to a blend of thermoplastic polymers which form a single phase solid solution of excellent optical clarity and good flexural properties.
BACKGROUND OF THE INVENTION
Thermoplastic polymers useful for injection molding and extrusion to form molded articles and films often are deficient in one or more properties. Efforts to modify the properties of a polymer that is otherwise suitable, for example, by blending it with another polymer usually produce an opaque or cloudy blend which is not acceptable when the molded article or film must be clear and transparent. For example, U.S. Pat. No. 4,141,927 to White et al. discloses blends of polyetherimides and of polyesters based primarily on terephthalic acid and isophthalic acid. The patent discloses blends which formed multiple phase solid state solutions in the composition range from about 25 to 90 weight percent polyester. Such compositions are understood to be opaque and cloudy. Blends of polyarylates with polyetherimide are disclosed in the U.S. Pat. No. 4,250,279 to Robeson et al., and U.S. Pat. No. 4,908,419 to Holub et al. Three components blends of polyetherimide, polyester and a third polymer are also disclosed in U.S. Pat. No. 4,687,819 to Quinn et al. and U.S. Pat. No. 4,908,418 to Holub. None of these patents suggests a polymer composition having the combination of desired flexural properties, clarity and transparency.
There is a continuing need for thermoplastic polymer compositions that have high flexural moduli, high flexural strength and high heat deflection temperatures and that can be injection molded or extruded to form articles of excellent clarity and transparency.
BRIEF SUMMARY OF THE INVENTION
The composition of the invention is a visually clear blend of thermoplastic polymers comprising (A) a polyetherimide which is described in more detail hereinafter and (B) a polyester of a dicarboxylic acid component comprising 2,6-naphthalene dicarboxylic acid and a glycol component comprising at least one aliphatic or cycloaliphatic glycol selected from the group consisting of ethylene glycol, 1,3-trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, neopentyl glycol, 1,4-cyclohexanedimethanol and diethylene glycol.
The invention also includes molded articles and films formed of the novel polymer blend. In addition, the invention includes a method for improving the physical properties of a polymer composition comprising a polyester of 2,6-naphthalene dicarboxylic acid that comprises melt blending or solution blending with the polyester a polyetherimide of the type described herein to form a single phase solid solution which is clear and transparent and of higher flexural modulus than the polyester.
REFERENCES:
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patent: 3847869 (1974-11-01), Williams
patent: 3850885 (1974-11-01), Takekoshi et al.
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patent: 4141927 (1979-02-01), White et al.
patent: 4250279 (1981-02-01), Robeson et al.
patent: 4687819 (1987-08-01), Quinn et al.
patent: 4835047 (1989-05-01), Isayer et al.
patent: 4908418 (1990-03-01), Holub
patent: 4908419 (1990-03-01), Holub et al.
patent: 5284903 (1994-02-01), Minnick
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M. M. Coleman, C. J. Serman, D. E. Bhagwagar, P. C. Painter,Polymer, 31, 1187 (1990).
Boshears Betty J.
Eastman Chemical Company
Gwinnell Harry J.
Harding Karen A.
Woodward Ana
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