Toyo Boseki Kabushiki Kaisha

Takao Kashihara

Tatsuhiko Shizuki

Tadashi Ikegami

Akitada Osako

Seiji Endo

Ken Murayama

Ohguchi Masakatsu

Copolyesters of improved dyeability are formed from dicarboxylic acid components and glycol components. The new polyesters are characterized in that more than 80 mol percent of the dicarboxylic acids is terephthalic acid or its ester-forming derivative and that more than 80 mol percent of the glycols is a glycol or two or more glycols selected from ethylene glycol, tetramethylene glycol and 1,4-cyclohexane dimethanol and 1 to 10 weight percent thereof, based on the resulting polyester is a glycol represented by the following formula (I):

Copolyesters

The present invention relates to a flame retardant polyester having a phosphorus atom content of 500-50,000 ppm, which polyester contains a flame-retarding amount of a phosphorus containing compound represented by the following general formula: ##STR1## wherein each of R.sup.1 is a hydrogen atom or hydrocarbon group having 1-10 carbon atoms which may contain a hydroxyl group, and both R.sup.1 's may together form a dehydrated ring when both of R.sup.1 's represent hydrogen atoms, each of R.sup.2 and R.sup.3 is a member selected from the group consisting of halogen atoms and hydrocarbon groups having 1-10 carbon atoms, and each of n2 and n3 is an integer of 0-4. Polyesters containing the claimed phosphorus containing compounds are characterized by exhibiting excellent flame retardancy and at the same time, the physical properties of the polyesters are not impaired by incorporation of the phosphorus compound therein.

Phosphorus-containing polyesters

The present invention relates to a phosphorus-containing compound of the formula ##STR1## wherein each of R.sup.1 is a hydrogen atom or hydrocarbon group having 1-10 carbon atoms which may contain a hydroxyl group, and both R.sup.1 's may together form a dehydrated ring when both of R.sup.1 's represent hydrogen atoms, each of R.sup.2 and R.sup.3 is a member selected from the group consisting of halogen atoms and hydrocarbon groups having 1-10 carbon atoms, and each of n2 and n3 is an integer of 0-4. These compounds are especially useful for incorporation into polymers, such as polyesters, as flame-retardants. Further, such phosphorus-containing compound imparts excellent flame-retardant properties to such polyesters, while at the same time does not deleteriously affect the physical properties of the polyester.

Phosphorus-containing compounds

Novel flame resistant polyesters provided with improved moldability. The polyester comprising a combination of an aromatic dicarboxylic acid or an ester-forming derivative thereof, a diol or an ester-forming derivative thereof, and a particular phosphorus compound having at least two ester-forming functional groups. The content of phosphorus in the polyester is about 500-50,000 ppm.

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Otsu, Japan

Takao Kashihara