# US 12,179,418 B2 · Siloxane additive manufacturing composition

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- Number: US 12,179,418 B2
- Document ID: US12179418B2
- Status: Granted
- Kind: B2
- Application number: 17/438,084
- Filed: 2020-03-17
- Published: 2022-06-16
- Granted: 2024-12-31
- Earliest claimed: 2019-03-20
- Assignees: Spectroplast AG
- Applicants: Spectroplast AG
- Inventors: Manuel Schaffner
- Web page: https://patentgrep.com/patent/US12179418B2

## CPC

- B29C 64/129: characterised by the energy source therefor, e.g. by global irradiation combined with a mask
- C08L 83/04: Polysiloxanes
- B29C 64/245: Platforms or substrates (support structures intended to be sacrificed after manufacture B29C64/40)
- B29C 64/286: Optical filters, e.g. masks
- C08G 77/20: containing silicon bound to unsaturated aliphatic groups
- C08G 77/28: sulfur-containing groups
- B33Y 10/00: Processes of additive manufacturing
- B33Y 30/00: Apparatus for additive manufacturing; Details thereof or accessories therefor
- B33Y 70/00: Materials specially adapted for additive manufacturing
- B33Y 80/00: Products made by additive manufacturing
- 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)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- 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

## Abstract

Additive manufacturing compositions are disclosed that include at least one alkenyl-derivatized polysiloxane and at least one mercapto-derivatized polysiloxane crosslinking agent of formula (I): R1(R)2SIO((R3R4)SiO)xSi(R)2R2 (I), wherein R is independently C(1-12)alkyl; R1, R2, R3, R4 are independently C(1-12)alkyl, or mercapto-C(1-12)alkyl; x is 1 or more; with the proviso that at least one of R1, R2, R3, R4 is mercapto-C(1-12)alkyl, and wherein the at least one alkenyl-derivatized polysiloxane and the at least one mercapto-derivatized polysiloxane crosslinking agent form a stable emulsion; their use in additive manufacturing as well as 3D printed silicone objects obtained from these compositions.

## Claims

### Claim 1

An additive manufacturing composition comprising:
at least one alkenyl-derivatized polysiloxane and at least one mercapto-derivatized polysiloxane crosslinking agent of formula (I):
R1(R)2SiO((R3R4)SiO)xSi(R)2R2 (I),
wherein R is independently C(1-12)alkyl, preferably methyl;
R1, R2, R3, R4 are independently C(1-12)alkyl, preferably methyl, or mercapto-C(1-12)alkyl;
x is 1 or more;
with the proviso that at least one of R1, R2, R3, R4 is mercapto-C(1-12)alkyl, and wherein the alkenyl-derivatized polysiloxane and the mercapto-derivatized polysiloxane crosslinking agent form a stable emulsion;
wherein the alkenyl-derivatized polysiloxane forms a continuous phase of the emulsion and the mercapto-derivatized polysiloxane crosslinking agent forms a discontinuous phase, wherein the discontinuous phase is present as droplets having a diameter of no more than 100 micrometers.

### Claim 2 (depends on 1)

The additive manufacturing composition of claim 1 further comprising at least one photoinitiator.

### Claim 3 (depends on 1)

The additive manufacturing composition of claim 1 which is curable by UV-visible radiation.

### Claim 4 (depends on 1)

The additive manufacturing composition of claim 1 wherein the at least one alkenyl-derivatized polysiloxane is one polysiloxane or a blend of two or more polysiloxanes.

### Claim 5 (depends on 1)

The additive manufacturing composition of claim 1 wherein the at least one alkenyl-derivatized polysiloxane is selected from alkenyl-derivatized poly(dimethylsiloxane), alkenyl-derivatized poly(diphenylsiloxane), alkenyl-derivatized poly(methylphenylsiloxane), alkenyl-derivatized poly(dimethyldiphenylsiloxane), preferably Ecoflex® 00-15, Ecoflex® 00-20, Dragon Skin™ 30, Sorta-Clear® 40 (KauPo, DE), PlatSil® 73-15 (Mouldlife, GB), Sylgard® 184 (Sigma-Aldrich, CH), Zhermack 00 Zhermack 08, Zhermack 13 (Zhermack, DE), LS-8941 (NuSil, USA), KE-2061 (Shin-Etsu Chemical, JP), Vinyl Q-resin dispersion in vinyl terminated polydimethylsiloxane (Gelest Inc., DE).

### Claim 6 (depends on 1)

The additive manufacturing composition of claim 1 wherein the alkenyl group in the at least one alkenyl-derivatized polysiloxane is a vinyl, allyl, butenyl or pentenyl group, preferably a vinyl group.

### Claim 7 (depends on 1)

The additive manufacturing composition of claim 1 wherein mercapto-C(1-12)alkyl is mercapto-C(1-6)alkyl, preferably mercapto-methyl, mercapto-ethyl, mercapto-butyl, mercapto-propyl.

### Claim 8 (depends on 1)

The additive manufacturing composition of claim 1 wherein the at least one mercapto-derivatized polysiloxane crosslinking agent is of formula (I) wherein R, R1, R2, R4 are independently C(1-12)alkyl, preferably methyl; R3 is independently mercapto-C(1-12)alkyl; x is 1 or more.

### Claim 9 (depends on 1)

The additive manufacturing composition of claim 1 wherein the at least one mercapto-derivatized polysiloxane crosslinking agent is of formula (I) wherein R, R1, R2 are independently C (1-12)alkyl, preferably methyl; R3, R4 are independently mercapto-C(1-12)alkyl; x is 1 or more.

### Claim 10 (depends on 1)

The additive manufacturing composition of claim 1 wherein x is 1 to 100,000.

### Claim 11 (depends on 1)

The additive manufacturing composition of claim 1 wherein the at least one mercapto-derivatized polysiloxane is (mercaptopropyl)methylsiloxane homopolymer having 1 or more mercaptopropyl units.

### Claim 12 (depends on 1)

The additive manufacturing composition of claim 1 having a viscosity of 100 Pa*s or below.

### Claim 13 (depends on 1)

Use of the additive manufacturing composition of claim 1 for forming a 3-dimensional object using one of stereolithography, laser based stereolithography (SLA) and digital light processing (DLP), material jetting, drop on demand, volumetric 3D printing, holographic laser 3D printing, material extrusion, fused deposition modeling, and DLP in a top-down orientation.

### Claim 14 (depends on 1)

A method of preparing an additive manufacturing composition according to claim 1 comprising the steps of combining the at least one alkenyl-derivatized polysiloxane and at least one mercapto-derivatized polysiloxane crosslinking agent of formula (I) under shearing to obtain the composition in form of an emulsion.

### Claim 15 (depends on 1)

A cured composition prepared from the additive manufacturing composition of claim 1.

### Claim 16 (depends on 15)

The cured composition of claim 15 having a transparency of >80%.

### Claim 17 (depends on 1)

A method of preparing a cured composition, in particular a 3D printed silicone, the method comprising:
a) preparing a 3D model of a preproduct;
b) additive manufacturing of the preproduct according to the 3D model of the preproduct using an additive manufacturing composition according to claim 1 and an additive manufacturing device;
c) curing the preproduct thereby providing the cured composition.

### Claim 18 (depends on 17)

The method according to claim 17, wherein the additive manufacturing device comprises a radiation source for irradiating at least a portion of the additive manufacturing composition.

### Claim 19 (depends on 18)

The method according to claim 18, wherein in step b) additive manufacturing is performed by light polymerization, wherein additive manufacturing is performed by VAT photopolymerization, volumetric 3D printing or holographic laser 3D printing.

### Claim 20 (depends on 17)

The method according to claim 17, wherein the additive manufacturing device comprises a chamber containing the additive manufacturing composition and a platform within the chamber which is moved in the z-direction during step b).

### Claim 21 (depends on 20)

The method according to claim 20, wherein in step a) the 3D model of the preproduct is prepared such that the stability of the preproduct is maximized.

### Claim 22 (depends on 20)

The method according to claim 20, wherein in step a) the center of mass of the preproduct is determined and that the 3D model of the preproduct is prepared such that a distance between the center of mass of the preproduct and the platform is minimized.

### Claim 23 (depends on 20)

The method according to claim 20, wherein in step a), the 3D model of the preproduct is prepared such that the surface area of the preproduct being in contact with the platform and/or the projected surface area from the preproduct to the build platform is maximized.

### Claim 24 (depends on 18)

The method according to claim 18, wherein the additive manufacturing device comprises a recoater and wherein step b) comprises the steps:
i) dipping the platform into the additive manufacturing composition at a predefined height;
ii) moving the platform such that at least the applied layer of additive manufacturing composition is above the additive manufacturing composition;
iii) providing a film of the additive manufacturing composition with a predefined thickness by wiping the applied layer of the additive manufacturing composition with the recoater;
iv) irradiating the applied film of the additive manufacturing composition with the radiation source;
v) moving the platform in the z-direction;
vi) repeating steps ii), iii) iv) and/or v).

### Claim 25 (depends on 24)

The method according to claim 24, wherein the radiation source is moved into a predefined focal distance before step iv).

### Claim 26 (depends on 24)

The method according to claim 24, wherein in step iv) illuminating the applied film is performed for more than 1 ms.

### Claim 27 (depends on 17)

The method according to claim 17, wherein the additive manufacturing device comprises a sealable housing and wherein the housing is free of oxygen and filled or pressurized with an inert gas.

### Claim 28 (depends on 17)

The method according to claim 17, wherein the additive manufacturing composition is maintained at a predefined printing temperature during step b).

### Claim 29 (depends on 18)

The method according to claim 18, wherein the intensity of irradiation is reduced by 0-99%.

### Claim 30 (depends on 29)

The method according to claim 29, wherein the intensity is reduced by digitally changing the grey scale of the projector and/or by providing a physical filter between the radiation source and additive manufacturing composition.

### Claim 31 (depends on 17)

The method according to claim 17, wherein in step c) curing comprises prewashing the preproduct, preferably with a solvent, and/or post-curing under UV irradiation and/or swelling the preproduct with a solvent, preferably an alkane, and/or drying the preproduct at a curing temperature.

### Claim 32 (depends on 17)

A cured composition prepared by the method according to claim 17.

### Claim 33 (depends on 8)

An additive manufacturing composition according to claim 8, wherein x is 1 to 10,000,000.

### Claim 34 (depends on 9)

An additive manufacturing composition according to claim 9, wherein x is 1 to 10,000,000.

### Claim 35 (depends on 11)

An additive manufacturing composition according to claim 11, wherein the at least one mercapto-derivatized polysiloxane is (mercaptopropyl)methylsiloxane homopolymer having 2 to 100,000 mercaptopropyl units.

### Claim 36 (depends on 16)

The cured composition of claim 16 having a transparency of >90%.

### Claim 37 (depends on 26)

The method according to claim 26, wherein in step iv) illuminating the applied film is performed for more than 50 ms.