# US 2019/0375952 A1 · Powder of spherical crosslinkable polyamide particles, preparation process and use with the selective laser sintering technique

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- Number: US 2019/0375952 A1
- Document ID: US20190375952A1
- Status: Published application
- Kind: A1
- Application number: 16/472,318
- Filed: 2017-12-21
- Published: 2019-12-12
- Earliest claimed: 2016-12-22
- Assignees: SETUP Performance SAS
- Applicants: SETUP Performance SAS
- Inventors: Jérome GIMENEZ
- Web page: https://patentgrep.com/patent/US20190375952A1

## CPC

- C08G 69/48: Polymers modified by chemical after-treatment
- C09D 11/101: Inks specially adapted for printing processes involving curing by wave energy or particle radiation, e.g. with UV-curing following the printing
- B29B 9/12: characterised by structure or composition
- B33Y 70/10: Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
- C08J 3/203: {Solid polymers with solid and/or liquid additives}
- C08J 3/24: Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K)
- C08L 77/02: Polyamides derived from omega-amino carboxylic acids or from lactams thereof (C08L77/10 takes precedence)
- C08L 77/06: Polyamides derived from polyamines and polycarboxylic acids (C08L77/10 takes precedence)
- C09D 11/102: containing macromolecular compounds obtained by reactions other than those only involving unsaturated carbon-to-carbon bonds
- B29C 64/153: using layers of powder being selectively joined, e.g. by selective laser sintering or melting
- B29K 2077/00: Use of {PA, i.e.} polyamides, e.g. polyesteramides {or derivatives thereof}, as moulding material
- B29K 2105/24: crosslinked or vulcanised
- B33Y 10/00: Processes of additive manufacturing
- C08J 2377/02: Polyamides derived from omega-amino carboxylic acids or from lactams thereof (C08J2377/10 takes precedence)
- C08J 2377/06: Polyamides derived from polyamines and polycarboxylic acids (C08J2377/10 takes precedence)
- C08K 5/5419: containing at least one Si—C bond
- C08L 2205/18: Spheres
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

The present invention provides a powder of spherical particles of crosslinkable polyamide suitable for the technique of selective laser sintering (SLS), and also a process for the production of such a powder of spherical particles of crosslinkable polyamide. The present invention also provides the production of articles by SLS, followed by a crosslinking step, starting from said powder of spherical particles of crosslinkable polyamide.

## Claims

### Claim 1

A powder of spherical particles of polyamide (I) functionalized by crosslinking functions Rt rendering it crosslinkable, characterized in that said crosslinking functions Rt are present at the surface and in the mass of said particles and in that said particles of crosslinkable polyamide (I) have a mean diameter d50 in the range 20 μm to 100 μm.

### Claim 2 (depends on 1)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 1, characterized in that the mean diameters d90 and d10 of said particles of crosslinkable polyamide (I) are such that (d90-d10) is in the range 10 μm to 80 μm.

### Claim 3 (depends on 1)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 1, characterized in that the polyamide is an aliphatic or semi-aromatic, semi-crystalline polyamide.

### Claim 4 (depends on 1)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 1, characterized in that the polyamide is selected from the group consisting of PA 6, PA 6.6, PA 10.10, PA 10.12, PA 11 and PA 12.

### Claim 5 (depends on 1)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 1, characterized in that the crosslinking functions Rt are selected from the group consisting of alkoxysilane, chlorosilane and acyloxysilane groups.

### Claim 6 (depends on 1)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 1, characterized in that the crosslinking functions Rt are introduced onto a polyamide (II) by grafting.

### Claim 7 (depends on 6)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 6, characterized in that the crosslinking functions Rt are supplied by grafting, directly onto the amine and/or carboxyl and/or amide functions of the polyamide (II), termed reactive functions Rr, of a crosslinking agent (III) with formula:
Rg-R1-Si(R2)3-a(R3)a (III)
in which:
a=0, 1, or 2;
Rg is a grafting function that is capable of reacting with Rr;
R1 is a divalent hydrocarbon group or a covalent bond connecting Si directly to Rg;
R2 is an alkoxy or acyl group or represents a halogen, the groups R2 being identical or different when a=0 or 1;
R3 is an alkyl group, the groups R3 being identical or different when a=2.

### Claim 8 (depends on 7)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 7, characterized in that the grafting function Rg of the crosslinking agent (III) comprises at least one group selected from:
the amino group —NH2;
groups having an ethylenic unsaturation;
epoxy groups;
the thiol function —SH;
halogen atoms;
the isocyanate group —N═C═O; and
the acylurea group —CO—NH—CO—NH2 or the alkylurea group R—NH—CO—NH2, with R representing a divalent hydrocarbon group.

### Claim 9 (depends on 7)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 7, characterized in that the crosslinking agent (III) is such that a=0, R1 is a divalent hydrocarbon group, R2 is an alkoxy group, Rg is an epoxy group.

### Claim 10 (depends on 1)

A powder of spherical particles of crosslinkable polyamide (I) according to claim 1, characterized in that the crosslinkable polyamide (I) has a proportion of crosslinking functions Rt in the range 0.3% to 9% by weight relative to the total weight of crosslinkable polyamide.

### Claim 11 (depends on 1)

A process for the preparation of a powder of particles of crosslinkable polyamide (I) according to claim 1, characterized in that it comprises the following steps:
a) providing a powder of spherical particles of a polyamide (II), said particles having a mean diameter d50 in the range 20 μm to 100 μm;
b) providing a crosslinking agent (III) comprising both at least one crosslinking function Rt and also at least one grafting function Rg that is capable of reacting with the amine and/or carboxyl and/or amide functions of the polyamide (II), termed reactive functions Rr;
c) mixing the powder of spherical particles of polyamide (II) with the crosslinking agent (III) in order to obtain a mixture (II+III);
d) heating the mixture (II+III) obtained from step c) to a temperature T1 that is in the range from the glass transition temperature of the polyamide (II) Tg(II)+5° C. to the glass transition temperature of the polyamide (II) Tg(II)+70° C. if Tg(II)+70° C.≤Tcryst(II)−35° C., or in the range from Tg(II)+5° C. to the crystallization temperature of the polyamide (II) Tcryst(II)−35° C. if Tg(II)+70° C.≤Tcryst(II)−35° C., in order to obtain a powder of spherical particles of polyamide impregnated with crosslinking agent (IV); and
e) heating the polyamide powder impregnated with crosslinking agent (IV) to a temperature T2 that is higher than T1 and lower than the crystallization temperature Tcryst(II) of the polyamide (II), in order to obtain a powder of crosslinkable polyamide (I).

### Claim 12 (depends on 11)

A process for the preparation of a powder of spherical particles of crosslinkable polyamide (I) according to claim 11, characterized in that the crosslinking agent (III) has the following formula:
Rg-R1-Si(R2)3-a(R3)a (III)
in which:
a=0, 1, or 2;
Rg is a grafting function that is capable of reacting with the reactive functions Rr of the polyamide (II);
R1 is a divalent hydrocarbon group or a covalent bond connecting Si directly to Rg;
R2 is an alkoxy or acyl group or a halogen, the groups R2 being identical or different when a=0 or 1;
R3 is an alkyl group, preferably a C1-C6 alkyl group, the groups R3 being identical or different when a=2.

### Claim 13 (depends on 11)

A process for the preparation of a powder of spherical particles of crosslinkable polyamide (I) according to claim 11, characterized in that the mixture in step c) is produced with a proportion of crosslinking agent (III) in the range 1% to 10% by weight, relative to the total weight of crosslinking agent (III) and of polyamide (II).

### Claim 14 (depends on 1)

A process for the preparation of a powder of spherical particles of crosslinkable polyamide (I) according to claim 1, characterized in that it comprises a step f) subsequent to step e) for adding a flow agent, a reinforcing filler, a flame retardant, a thermal stabilizer, an antistatic or conductive agent, or a colorant.

### Claim 15 (depends on 1)

Use of a powder of spherical particles of crosslinkable polyamide (I) according to claim 1, for the preparation of intermediate articles by the selective laser sintering technique.

### Claim 16 (depends on 1)

A process for the preparation of an intermediate article from a powder of spherical particles of crosslinkable polyamide (I) according to claim 1, using the selective laser sintering technique.

### Claim 17 (depends on 16)

A process for the preparation of an article, comprising:
i. forming an intermediate article using the selective laser sintering technique, starting from a powder of spherical particles of crosslinkable polyamide (I) according to the process of claim 16; and
ii. crosslinking at least a portion of the crosslinkable functions Rt of said crosslinkable polyamide (I) of the intermediate article.

### Claim 18 (depends on 17)

The process according to claim 17, characterized in that the crosslinking is carried out by hydrolysis, in particular in ambient air.

### Claim 19 (depends on 17)

An article produced from a powder of spherical particles of crosslinkable polyamide (I) in accordance with the process of claim 17.