Novel polyesters prepared from mixture of hydroquinone and bisphenols
AssigneeTeijin Limited
InventorsHiroo Inata, Shoji Kawase
Life of this patent
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Abstract
A linear copolyester having a reduced specific viscosity of at least 0.5 is prepared from terephthalic or isophthalic acid, a bisphenol and hydroquinone. The ester unit derived from terephthalic or isophthalic acid and hydroquinone is contained in the copolyester in a proportion of 5 to 35 mole%. The copolyester has superior crack resistance, thermal stability, transparency and chemical resistance.
Claims6
A linear copolyester having ( 1) a reduced specific viscosity of at least 0.5, measured at 35.degree. C using a mixed solvent consisting of phenol and tetrachloroethane in a weight ratio of 60:40 while maintaining a concentration of 1.2 g/deciliter for the copolyester, and (2) a light transmittance retention of at least 50% after immersion for 1 day in acetone at room temperature,
- said copolyester comprising
- a. an ester unit derived from at least one aromatic dicarboxylic acid selected from the group consisting of terephthalic acid and isophthalic acid, and hydroquinone, and
- b. an ester unit derived from at least one aromatic dicarboxylic acid selected from the group consisting of terephthalic acid and isophthalic acid, and a bisphenol of the formula ##STR2## wherein R.sub.1 and R.sub.2, independently of each other, represent alkyl containing 1 to 6 carbon atoms, and may be linked to each other,
- the proportion of said ester unit (a) being 5 to 35 mole % based on the total of ester units (a) and (b).
Dependencies are inferred from the claim text.