Water-soluble block copolymer and use thereof as a support material for 3D printing

1. A support material for an additive system for a digital manufacture of objects, said support material comprising a block copolymer wherein the block copolymer comprises:

at least one partially or totally hydrophilic elastomeric block, wherein the elastomeric block has a Tg of less than 30° C. and comprises at least one hydrophilic monomer, and

at least one water-soluble thermoplastic block, wherein the thermoplastic block has a Tg of greater than 30° C. and comprises at least one monomer bearing a carboxyl groups;

wherein the copolymer is partially or totally soluble in water or in aqueous medium, and a mass proportion of the thermoplastic block is greater than 50% of a weight of the block copolymer.

2. The support material according to claim 1 , wherein the hydrophilic monomer is selected from the group consisting of:

acrylic acid; methacrylic acid;

hydroxyalkyl (meth)acrylates in which the alkyl group comprises 2 to 4 carbon atoms; (meth)acrylamides in which the alkyl group comprises 2 to 4 carbon atoms; polyethylene glycol and glycol acrylates optionally substituted on their terminal function with alkyl, phosphate, phosphonate or sulfonate groups; polyethylene glycol and glycol methacrylates optionally substituted on their terminal function with alkyl, phosphate, phosphonate or sulfonate groups; and mixtures thereof.

3. The support material according to claims 1 , wherein the monomer bearing a carboxyl group is selected from the group consisting of: acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, vinylbenzoic acid, the acrylamidoglycolic acid of formula CH 2 ═CH—CONHCH(OH)COOH, carboxylic anhydrides bearing a vinyl bond, salts thereof, and mixtures thereof.

4. The support material according to claims 1 , wherein the block copolymer consists of an elastomeric block and a thermoplastic block.

5. The support material according to claim 1 , wherein a mass content of the carboxyl functions in the block copolymer ranges from 10 to 40 relative to the weight of said the block copolymer.

6. The support material according to claim 1 , wherein the block copolymer is extrudable and granulable.

7. The support material according to claim 1 , wherein the mass proportion of the thermoplastic block is greater than or equal to 60% of the weight of said copolymer.

8. The support material according to claim 1 , wherein a Tg of said thermoplastic block of said block copolymer is between 50° C. and 250° C.

9. The support material according to claims 1 , wherein the block copolymer has the structure: P(BA-MPEGMA)-b-P(BA-S-MAA).

10. A process for preparing a block copolymer used as support material according to claim 1 , wherein the process comprises carrying out controlled radical polymerization in the presence of a nitroxide mediator.

11. The process according to claim 10 , wherein the controlled radical polymerization uses an alkoxyamine of formula II:

12. A process for manufacturing objects via a digital manufacturing additive system which uses as support material the block copolymer according to claim 1 .

13. The process according to claim 12 , wherein the digital manufacturing additive system is fused deposition modeling.

14. The process according to claim 12 , wherein the digital manufacturing additive system is laser sintering.

15. The support material according to claim 1 , wherein the hydrophilic monomer is selected from the group consisting of: 2-hydroxyethyl methacrylate, 2 hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, dimethylacrylamide, and N-(2-hydroxypropyl)(meth)acrylamide, and mixtures thereof.

16. The support material according to claim 2 , wherein the monomer bearing a carboxyl group is selected from the group consisting of: acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, vinylbenzoic acid, the acrylamidoglycolic acid of formula CH 2 ═CH—CONHCH(OH)COOH, carboxylic anhydrides bearing a vinyl bond, salts thereof, and mixtures thereof.

17. The support material according to claim 15 , wherein the monomer bearing a carboxyl group is selected from the group consisting of: acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, vinylbenzoic acid, the acrylamidoglycolic acid of formula CH 2 ═CH—CONHCH(OH)COOH, carboxylic anhydrides bearing a vinyl bond, salts thereof, and mixtures thereof.