TOUGHENED BRANCHED POLY(HYDROXYACID) COMPOSITION

1 . A composition comprising: a branched poly(hydroxyacid) polymer, polymer (HAP), obtained from the polycondensation reaction of a monomer mixture comprising:

(i) at least one hydroxyacid having only one hydroxyl group and only one carboxylic acid group, hydroxyacid (A);

(ii) optionally at least one carboxylic acid having one or two carboxylic acid groups and being free from hydroxyl group, acid (C), and (iii) at least one polyfunctional reactant different from hydroxyacid (A) and acid (C), reactant (F), selected from the group consisting of:

compounds containing at least one epoxy functional group; and

mixtures comprising at least one polyol comprising at least three hydroxyl groups and being free from carboxylic acid group, polyol (H), and at least one polyacid comprising at least two carboxylic acid groups and being free from hydroxyl groups, polyacid (O); and

mixtures comprising at least one polyol comprising at least three hydroxyl groups and being free from carboxylic acid group, polyol (H), and at least one alcohol comprising one or two hydroxyl groups and being free from carboxylic acid group, alcohol (AQ),

and a chain extending agent comprising epoxy functional groups and having a number average functionality ≥2, agent (CE), in an amount of from 0.01 to less than 1.00 wt % with respect to the combined weight of polymer (HAP) and agent (CE).

2 . The composition according to claim 1 wherein polymer (HAP) is obtained from the polycondensation reaction of a monomer mixture comprising at least one hydroxyacid (A) which is glycolic acid and a reactant (F) which is a mixture comprising at least one polyol (H) comprising at least three hydroxyl groups and at least one polyacid (O) comprising at least three carboxylic acid groups.

3 . The composition according to claim 1 wherein polymer (HAP) is obtained from the polycondensation reaction of a monomer mixture comprising at least one hydroxyacid (A) which is glycolic acid; optionally at least one acid (C); and at least one reactant (F) selected from mixtures comprising at least one polyol (H) comprising at least three hydroxyl groups, at least one polyacid (O) comprising at least three carboxylic acid groups, and wherein the amount of acid (C), when present, is such that the number of carboxylic acid groups thereof is comprised between 0.0001 to 0.010% with respect to the number of hydroxyl groups of hydroxyacid (A).

4 . The composition according to claim 1 wherein polymer (HAP) is obtained from the polycondensation reaction of a monomer mixture comprising glycolic acid; optionally, at least one hydroxy acid (A) different from glycolic acid, in an amount of at most 5% moles, with respect to the sum of moles of glycolic acid and hydroxy acid (A); optionally at least one carboxylic acid (C) having one carboxylic acid group; and at least one reactant (F) selected from mixtures comprising at least one polyol (H) comprising at least three hydroxyl groups and at least one polyacid (O) selected from the aromatic acids comprising two aromatic carboxylic acid groups and wherein: the amount of polyol (H) is such that the number of hydroxyl groups thereof is comprised between 0.050 to 1.200% with respect to the overall number of carboxyl groups of glycolic acid and the hydroxyacid (A), if present; the amount of polyacid (O) is such that the number of carboxylic acid groups thereof is comprised between 0.050 to 0.750% with respect to the overall number of hydroxyl groups of glycolic acid and of the hydroxy acid (A), if present; and the amount of acid (C), when present, is such that the number of carboxylic acid groups thereof is comprised between 0.0001 to 0.010% with respect to the overall number of hydroxyl groups of glycolic acid and of the hydroxy acid (A), if present.

5 . The composition according to claim 1 wherein polymer (HAP) is obtained from the polycondensation reaction of glycolic acid; optionally, at least one hydroxyacid (A) different from glycolic acid, wherein the molar amount of hydroxyacid (A) is of at most 5% moles with respect to the sum of moles of glycolic acid and hydroxyacid (A); optionally at least one carboxylic acid (C); optionally at least one polyacid (O); and at least one reactant (F) selected from mixtures comprising at least one polyol (H) and at least one alcohol (AO) wherein the amount of polyacid (O) is such that the number of carboxylic acid groups thereof is comprised between 0.025 and 1.200% with respect to the overall number of hydroxyl groups of glycolid acid and of the hydroxyacid (A), if present.

6 . The composition of anyone of claim 1 wherein agent (CE) is selected from the group consisting of di- or polyglycidyl esters of di- or polycarboxylic acids, di- or polyglycidyl ethers of di- or polyols, poly(ethylene-co-glycidylmethacrylate) copolymers, poly(ethylene-co-methyl (meth)acrylate-co-glycidyl acrylate) copolymers, poly(ethylene-co-n-butyl acrylate-co-glycidyl acrylate) copolymers,copolymers of styrene and glycidyl (meth)acrylates.

7 . The composition of claim 1 wherein agent (CE) is selected from the group consisting of the polymerization products of (i) at least one epoxy-functional (meth) acrylic monomer; and (ii) at least one styrenic and/or (meth) acrylic monomer.

8 . The composition of claim 1 comprising from 0.05 to 0.95 wt % of agent (CE) with respect to the combined weight of polymer (HAP) and agent (CE).

9 . A chain extended polymer, polymer (CEHAP), comprising a backbone comprising polymer (HAP) covalently bonded to units deriving from agent (CE), according to claim 1 , wherein the amount of units deriving from agent (CE) is from 0.01 to less than 1.00 wt % based on the weight of polymer (CEHAP).

10 . A process for the preparation of polymer (CEHAP) according to claim 9 , comprising reacting in the melt polymer (HAP) and from 0.01 to less than 1.00 wt % of agent (CE) with respect to the combined weight of polymer (HAP) and agent (CE).

11 . The process of claim 10 which is performed in an extruder and comprises either feeding the composition to said extruder or feeding polymer (HAP) and agent (CE) separately to said extruder.

12 . A process for the preparation of polymer (CEHAP) comprising a first step of polycondensing (i) at least one hydroxyacid (A), (ii) optionally at least one acid (C), and (iii) at least one polyfunctional reactant (F), as defined in claim 1 , in the molten state to form a pre-polymer, and a second step of solid state polymerization (SSP) wherein agent (CE) is added in an amount of from 0.01 to less than 1.0 wt % with respect to the combined weight of polymer (HAP) and agent (CE) either during the first polycondensing step or during the second solid state polymerization step.

13 . An article comprising the composition of claim 1 .

14 . The article of claim 13 which is a bottle, an article for hydrocarbon resource recovery, a downhole tool or a downhole tool member, a film for packaging, a feminine hygiene product, a disposable pod, a structural component for electronic applications or a biomedical article.

15 . A process for the manufacture of the article of claim 13 , said method comprising melt processing and injection molding or extruding the composition.

16 . The composition according to claim 1 wherein the compounds containing at least one epoxy functional group are selected from the group consisting of epoxysilanes and polyepoxides.

17 . An article comprising the polymer (CEHAP) of claim 9 .

18 . The article of claim 17 which is a bottle, an article for hydrocarbon resource recovery, a downhole tool or a downhole tool member, a film for packaging, a feminine hygiene product, a disposable pod, a structural component for electronic applications or a biomedical article.

19 . A process for the manufacture of the article of claim 17 , said method comprising melt processing and injection molding or extruding the polymer (CEHAP).