US 4,902,758 AGranted

Preparation of segmented block copolycarbonates

AssigneeThe Dow Chemical Company

InventorMaurice J. Marks

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Abstract

Segmented block copolycarbonates from diphenols and tetrahalogenated diphenols are prepared by phosgenation, under interfacial reaction conditions, initially at a higher pH during which diphenol polycarbonate oligomers are formed, and thereafter at a lower pH during which tetrahalogenated diphenol bischloroformates are formed, followed by copolymerization utilizing an activated pyridine catalyst. Alternatively, diphenol polycarbonate oligomers and tetrahalogenated diphenol chloroformates may be coupled, utilizing an activated pyridine catalyst, to prepare segmented block copolycarbonates.

Claims44

Dependent claims

A purpose for the preparation of a high molecular weight segmented block copolymer from a diphenol and a tetrahalogenated diphenol, comprising the steps of sequentially:

(A) contacting together a diphenol, a tetrahalogenated diphenol, an organic solvent, and an aqueous metal hydroxide to form a mixture, wherein the diphenol and tetrahalogenated diphenol are in the bisalkali metal phenolate form, and the pH of the aqueous phase of the mixture is within about 10% of the pH of an equilibrium composition consisting solely of an aqueous solution of a molar amount of the diphenol in two normal alkali metal hydroxide;
(B) next, continuously agitating the mixture, and adding to the agitated mixture phosgene, and an amount of additional alkali metal hydroxide sufficient to maintain the pH of the mixture within the about 10% range recited in step A, whereby diphenol polycarbonate oligomers having chloroformate end groups are prepared;
(C) thereafter, adding to the agitated mixture additional phosgene sufficient to attain a decreased pH of the aqueous phase to within about 10% of the pH of an equilibrium composition consisting solely of an aqueous solution of a molar amount of the tetrahalogenated diphenol in two normal alkali metal hydroxide;
(D) then, adding to the agitated mixture additional phosgene, while maintaining the pH of the aqueous phase of the mixture within the about 10% range recited in step C, whereby tetrahalogenated diphenol chloroformates are prepared;
and
(E) finally, adding to the mixture an amount of additional alkali metal hydroxide sufficient to attain and maintain an increased pH of the aqueous phase of the mixture within the about 10% range recited in step A,
and an amount of an activated pyridine selected from the group consisting of
4-aminopyridines of the general formula:
##STR11## wherein R.sub.1 and R.sub.2, together with N, form a cyclic alkyl structure, or are each independently a monovalent alkyl radical, or are each independently a polymer chain such that the formula weight of the catalyst is less than 50,000, and R.sub.3 is independently hydrogen or a monovalent alkyl radical, or
2-substituted pyridines of the general formula:
##STR12## wherein R is a monovalent alkyl radical, a cycloalkyl radical, or a polymer chain such that the formula weight of the catalyst is less than 50,000, and R.sub.3 is as previously defined,
sufficient to catalyze the coupling of the diphenol polycarbonate oligomers having chloroformate end groups and the tetrahalogenated diphenol chloroformates,
whereby a high molecular weight segmented block copolycarbonate is prepared.

10 more elements

A process for the preparation of a high molecular weight segmented block copolymer, comprising the steps of:

(A.sub.1) contacting together a diphenol polycarbonate oligomer having chloroformate end groups, a tetrahalogenated diphenol chloroformate, an organic solvent and an aqueous metal hydroxide to form a mixture, wherein the pH of the aqueous phase of the mixture is within about 10% of the pH of an equilibrium composition consisting solely of an aqueous solution of a molar amount of the diphenol polycarbonate in two normal alkali metal hydroxide;
and
(B.sub.1) thereafter, adding to the mixture an amount of an activated pyridine selected from the group consisting of
4-aminopyridines of the general formula:
##STR15## wherein R.sub.1 and R.sub.2, together with N, form a cyclic alkyl structure, or are each independently a monovalent alkyl radical, or are each independently a polymer chain such that the formula weight of the catalyst is less than 50,000, and R.sub.3 is independently hydrogen or a monovalent alkyl radical, or
2-substituted pyridines of the general formula:
##STR16## wherein R is a monovalent alkyl radical, a cycloalkyl radical, or a polymer chain such that the formula weight of the catalyst is less than 50,000, and R.sub.3 is as previously defined,
sufficient to catalyze the coupling of the diphenol polycarbonate oligomers having chloroformate end groups and the tetrahalogenated diphenol chloroformates,
whereby a high molecular weight segmented block copolycarbonate is prepared.

6 more elements

Dependencies are inferred from the claim text.

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Abstract

A purpose for the preparation of a high molecular weight segmented block copolymer from a diphenol and a tetrahalogenated diphenol, comprising the steps of sequentially:

(A) contacting together a diphenol, a tetrahalogenated diphenol, an organic solvent, and an aqueous metal hydroxide to form a mixture, wherein the diphenol and tetrahalogenated diphenol are in the bisalkali metal phenolate form, and the pH of the aqueous phase of the mixture is within about 10% of the pH of an equilibrium composition consisting solely of an aqueous solution of a molar amount of the diphenol in two normal alkali metal hydroxide;
(B) next, continuously agitating the mixture, and adding to the agitated mixture phosgene, and an amount of additional alkali metal hydroxide sufficient to maintain the pH of the mixture within the about 10% range recited in step A, whereby diphenol polycarbonate oligomers having chloroformate end groups are prepared;
(C) thereafter, adding to the agitated mixture additional phosgene sufficient to attain a decreased pH of the aqueous phase to within about 10% of the pH of an equilibrium composition consisting solely of an aqueous solution of a molar amount of the tetrahalogenated diphenol in two normal alkali metal hydroxide;
(D) then, adding to the agitated mixture additional phosgene, while maintaining the pH of the aqueous phase of the mixture within the about 10% range recited in step C, whereby tetrahalogenated diphenol chloroformates are prepared;
and
(E) finally, adding to the mixture an amount of additional alkali metal hydroxide sufficient to attain and maintain an increased pH of the aqueous phase of the mixture within the about 10% range recited in step A,
and an amount of an activated pyridine selected from the group consisting of
4-aminopyridines of the general formula:
##STR11## wherein R.sub.1 and R.sub.2, together with N, form a cyclic alkyl structure, or are each independently a monovalent alkyl radical, or are each independently a polymer chain such that the formula weight of the catalyst is less than 50,000, and R.sub.3 is independently hydrogen or a monovalent alkyl radical, or
2-substituted pyridines of the general formula:
##STR12## wherein R is a monovalent alkyl radical, a cycloalkyl radical, or a polymer chain such that the formula weight of the catalyst is less than 50,000, and R.sub.3 is as previously defined,
sufficient to catalyze the coupling of the diphenol polycarbonate oligomers having chloroformate end groups and the tetrahalogenated diphenol chloroformates,
whereby a high molecular weight segmented block copolycarbonate is prepared.

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