BRANCHED HARD- AND SOFT-BLOCK COPOLYMERS
The invention relates to a branched copolymer containing rigid blocks and flexible blocks, wherein the branchings are made by a polyol residue binding rigid blocks of the copolymer, said polyol being a polyol comprising at least three hydroxyl groups, said copolymer having a weight-average molar mass Mw of greater than or equal to 80 000 g/mol, and wherein the ratio of the weight-average molar mass Mw of the copolymer to the number-average molar mass Mn of the copolymer is greater than or equal to 2.2. The invention also relates to a process for manufacturing such a copolymer and also to a foam of such a copolymer, to a process for manufacturing such a foam and articles made from such a foam.
1 . A branched copolymer containing rigid blocks and flexible blocks, wherein the branchings are made by a polyol residue binding rigid blocks of the copolymer,
said polyol being a polyol comprising at least three hydroxyl groups,
said copolymer having a weight-average molar mass Mw of greater than or equal to 80 000 g/mol, and wherein the ratio of the weight-average molar mass Mw of the copolymer to the number-average molar mass Mn of the copolymer is greater than or equal to 2.2.
2 . The copolymer as claimed in claim 1 , having a weight-average molar mass Mw ranging from 80 000 to 300 000 g/mol.
3 . The copolymer as claimed in claim 1 , wherein the ratio of the weight-average molar mass Mw of the copolymer to the number-average molar mass Mn of the copolymer is greater than or equal to 2.4.
4 . The copolymer as claimed in claim 1 , wherein the ratio of the z-average molar mass Mz of the copolymer to the weight-average molar mass Mw of the copolymer is greater than or equal to 1.8.
5 . The copolymer as claimed in claim 1 , wherein the rigid blocks are chosen from polyamide blocks, polyester blocks, polyurethane blocks and a combination thereof.
6 . The copolymer as claimed in claim 1 , wherein the flexible blocks are chosen from polyether blocks, polyester blocks, and a combination thereof.
7 . The copolymer as claimed in claim 1 , being a copolymer containing polyamide blocks and polyether blocks.
8 . The copolymer as claimed in claim 5 , wherein the polyamide blocks are blocks of polyamide 6, of polyamide 11, of polyamide 12, of polyamide 5.4, of polyamide 5.9, of polyamide 5.10, of polyamide 5.12, of polyamide 5.13, of polyamide 5.14, of polyamide 5.16, of polyamide 5.18, of polyamide 5.36, of polyamide 6.4, of polyamide 6.9, of polyamide 6.10, of polyamide 6.12, of polyamide 6.13, of polyamide 6.14, of polyamide 6.16, of polyamide 6.18, of polyamide 6.36, of polyamide 10.4, of polyamide 10.9, of polyamide 10.10, of polyamide 10.12, of polyamide 10.13, of polyamide 10.14, of polyamide 10.16, of polyamide 10.18, of polyamide 10.36, of polyamide 10.T, of polyamide 12.4, of polyamide 12.9, of polyamide 12.10, of polyamide 12.12, of polyamide 12.13, of polyamide 12.14, of polyamide 12.16, of polyamide 12.18, of polyamide 12.36, of polyamide 12.T or mixtures thereof, or copolymers thereof.
9 . The copolymer as claimed in to claim 6 , wherein the polyether blocks are blocks of polyethylene glycol, of propylene glycol, of polytrimethylene glycol, of polytetrahydrofuran, or mixtures thereof, or copolymers thereof.
10 . The copolymer as claimed in claim 1 , wherein:
the rigid blocks of the copolymer have a number-average molar mass of from 400 to 20 000 g/mol; and/or
the flexible blocks of the copolymer have a number-average molar mass of from 100 to 6000 g/mol.
11 . The copolymer as claimed in claim 1 , wherein the mass ratio of the rigid blocks relative to the flexible blocks of the copolymer is from 0.1 to 20.
12 . The copolymer as claimed in claim 1 , wherein the polyol has a weight-average molar mass of less than or equal to 3000 g/mol.
13 . The copolymer as claimed in claim 1 , wherein the polyol is chosen from: pentaerythritol, trimethylolpropane, trimethylolethane, hexanetriol, diglycerol, methylglucoside, tetraethanol, sorbitol, dipentaerythritol, cyclodextrin, polyether polyols comprising at least three hydroxyl groups, and mixtures thereof.
14 . A foam of a copolymer containing rigid blocks and flexible blocks as claimed in claim 1 .
15 . The foam as claimed in claim 14 , having a density of less than or equal to 800 kg/m3.
16 . The foam as claimed in claim 14 , having a compression set after 30 minutes of less than or equal to 35%.
17 . A process of manufacturing a copolymer containing rigid blocks and flexible blocks as claimed in claim 1 , comprising the following steps:
the mixing of the polyol with precursors of the rigid blocks;
the synthesis of the rigid blocks;
the addition of the flexible blocks;
the condensation of the rigid blocks and of the flexible blocks.
18 . The process as claimed in claim 17 , wherein the polyol is mixed in an amount ranging from 0.01% to 10% by weight, relative to the total weight of the polyol, of the precursors of the rigid blocks and of the flexible blocks.
19 . A process for manufacturing a foam as claimed in claim 14 , comprising the following steps:
the mixing of the copolymer in the melt state, optionally with one or more additives, and with a blowing agent; and
the foaming of the mixture of copolymer and blowing agent.
20 . An article consisting of a foam as claimed in claim 14 .
21 . An article comprising at least one element consisting of a foam as claimed in claim 14 .
22 . The article as claimed in claim 20 , which is chosen from sports shoe soles, large or small balls, gloves, personal protective equipment, rail tie pads, motor vehicle parts, construction parts and electrical and electronic equipment parts.