Method for making branched polyesters reproducibly

Claim 2

In a method of preparing a branched polyester comprising: (1) forming a condensation polymer by reacting together (a) a diol; (b) a diacid; and (c) a polyfunctional modifier having at least three functional radicals; and (2) polycondensing said polymer in the presence of a transesterification catalyst at a reaction temperature and reaction pressure effective to form a polyester by linear extension and branching, the improvement comprising polycondensing said polymer while correlating the activity of said catalyst, said temperature and said pressure to restrain the extent of reaction for said linear extension to within about 0.1 percent of the extent of reaction for said branching.

Claim 3

The method of claim 1 wherein said polycondensing is in melt phase.

Claim 4

The method of claim 1 wherein said polycondensing is in solid phase.

Claim 5

The method of claim 1 wherein said reaction temperature is lowered and maintained at about 180° to about 240° C. during at least a part of said polycondensing.

Claim 6

The method of claim 1 wherein said reaction pressure is raised and maintained at about 5 to about 100 mmHg during at least a part of said polycondensing.

Claim 7

The method of claim 1 wherein the activity of said catalyst is decreased prior to completing said polycondensing.

Claim 8

In a method of preparing a branched polyester comprising: (1) forming a condensation polymer by reacting together (a) a diol of the formula RO--R 1 --OR 2 wherein each of R and R 2 is hydrogen or alkylcarbonyl and R 1 is an aliphatic, alicyclic or aromatic radical; (b) a diacid of the formula ##STR3## wherein n is 0 or 1, each of R 3 and R 5 is hydroxy, halogen or alkoxy or R 3 and R 5 together form an oxy linkage, and R 4 is an aliphatic, alicyclic or aromatic radical; and (c) a polyfunctional modifier having at least three functional radicals; and (2) polycondensing said polymer in the presence of a transesterification catalyst at a reaction temperature and a reaction pressure effective to form a polyester by linear extension and branching, the improvement comprising polycondensing said polymer while correlating the activity of said catalyst, said temperature and said pressure to restrain the extent of reaction for said linear extension to within about 0.1 percent of the extent of reaction for said branching.

Claim 9

In a method of preparing a branched polyester comprising: (1) forming a condensation polymer by reacting together (a) a diol of the formula RO--R 1 --OR 2 wherein each of R and R 2 is hydrogen or alkylcarbonyl and R 1 is an aliphatic, alicyclic or aromatic radical; (b) a diacid of the formula ##STR3## wherein n is 0 or 1, each of R 3 and R 5 is hydroxy, halogen or alkoxy or R 3 and R 5 together form an oxy linkage, and R 4 is an aliphatic, alicyclic or aromatic radical; and (c) a polyfunctional modifier having at least three functional radicals; and (2) polycondensing said polymer in the presence of a transesterification catalyst at a reaction temperature and a reaction pressure effective to form a polyester by linear extension and branching, the improvement comprising polycondensing said polymer while correlating the activity of said catalyst, said temperature and said pressure to restrain the extent of reaction for said linear extension to within about 0.1 percent of the extent of reaction for said branching.

Claim 10

The method of claim 7 wherein said reaction temperature is lowered and maintained at about 180° to about 240° C. during at least a part of said polycondensing.

Claim 11

The method of claim 7 wherein said reaction pressure is raised and maintained at about 5 to 100 mmHg during at least a part of said polycondensing.

Claim 12

The method of claim 7 wherein the activity of said catalyst is decreased prior to completing said polycondensing.

Claim 13

The method of claim 7 wherein said catalyst is a highly reactive transesterification catalyst.

Claim 14

The method of claim 7 wherein said catalyst is a poorly reactive transesterification catalyst.

Claim 15

The method of claim 7 wherein R 1 is hydrocarbon.

Claim 16

The method of claim 13 wherein R 1 is alkylene, cycloalkylene, cycloalkylenebisalkylene or arylene and each of R and R 2 is hydrogen.

Claim 17

The method of claim 7 wherein R 4 is hydrocarbon.

Claim 18

The method of claim 15 wherein R 4 is alkylene, cycloalkylene or arylene and each of R 3 and R 5 is hydroxy or alkoxy.

Claim 19

The method of claim 7 wherein said polyfunctional modifier is a polyol, polycarboxylic acid or hydroxy acid.

Claim 20

The method of claim 7 wherein said polyfunctional modifier has three or four functional radicals.

Claim 21

The method of claim 18 wherein said polyfunctional modifier is trimellitic anhydride or pentaerythritol.

Claim 22

The method of claim 7 wherein aid polyol, polycarboxylic acid or hydroxy acid is present in a concentration in the range of from about 0.1 to about 10 molar percent based on diacid.