Radiation-curable composition containing mercapto-functional polyorganosiloxanes for additive-manufacturing technology

1. A radiation-curable silicone composition for additive-manufacturing technology, the radiation-curable silicone composition comprising:

mercapto-functional polyorganosiloxane(s) as Component A,

organosiloxane(s) with at least two aliphatic unsaturated carbon-carbon moieties as Component B;

photo initiator(s) as Component C for initiating a curing reaction between Component A and Component B;

dye(s) as Component D; and

surfactant(s) as Component E, wherein the selected surfactant(s) is able to dissolve the dye(s).

2. The radiation-curable silicone composition of claim 1 , wherein the dye is characterized by the following features alone or in combination:

solubility: at least 0.5 wt. % at 50° C. in polyethylene glycol with an Mn of 400 g/mol;

having a light absorption maximum in the range of 460 to 600 nm;

comprising a perylene moiety;

color: red, orange or yellow;

amount: being present from 0.001 to 1 wt. % with respect to the weight of the whole radiation-curable composition.

3. The radiation-curable silicone composition of claim 1 , wherein the mercapto-functional polyorganosiloxane is characterized by the following features alone or in combination:

fraction of (mercaptoalkyl)methylsiloxane units: 7-100 mol-%;

being characterized by the following formula:

[(CH 3 ) 2 RSiO 1/2 ] w [(CH 3 ) 3 SiO 1/2 ] x [(CH 3 ) 2 SiO] y [R(CH 3 )SiO] z ,

with w being 0 to 0.1, x being 0 to 0.1 and w+x being 0.01 to 0.1; y being 0 to 0.93, z being 0.07 to 0.99, wherein each R is independently selected from a mercapto C 1 -C 10 hydrocarbyl group;

molecular weight (Mn): 500 to 20,000 g/mol;

viscosity: 10 to 1,000 mPa*s at 23° C.;

amount: being present in the composition of 0.5 to 50 wt. % with respect to the weight of the whole radiation-curable composition.

4. The radiation-curable silicone composition according of claim 1 , the surfactant is selected from the group consisting of:

a non-ionic surface-active substance according to the formula:

R 1 —O—[CH 2 CH 2 O] n —[R 2 O] m —R 3 ,

wherein:

R 1 is an aromatic or aliphatic, linear or branched hydrocarbon group having at least 8 carbon atoms,

R 2 represents an alkylene having 3 carbon atoms,

R 3 represents hydrogen or a C1-C3 alkyl group,

n is an integer selected from 0 to 40,

m is an integer selected from 0 to 40, and

n+m is at least 2;

a Si-containing surfactant according to the formula:

wherein:

each R is independently selected from a monovalent hydrocarbyl radical with 1 to 22 C-atoms,

R 1 is a divalent hydrocarbylene radical 1 to 26 C-atoms,

each R 2 is independently hydrogen or a lower hydroxyalkyl radical,

R 3 is hydrogen or a monovalent hydrocarbyl radical with 1 to 22 C-atoms,

n and b are independently an integer greater than or equal to zero, and

m and a are independently an integer greater than or equal to one; and

a polyether carbosilane accordingly to the formula:

Q-P—(OC n H 2n ) x -OT,

wherein:

Q is for (R) 3 —Si— or (R) 3 —Si—(R′—Si(R) 2 ) a —R′—Si(R″) 2 —,

each R is independently selected from an aliphatic C 1 -C 18 , a cycloaliphatic C 6 -C 12 , and an aromatic C 6 -C 12 hydrocarbon radical, which can optionally be substituted by halogen atoms,

R′ is a C 1 -C 14 alkylene group,

R″ is R in the case of a≠0, or

R″ is R or R 3 SiR′ in the case of a=0, and

a is an integer selected from 0-2;

P is a C 2 -C 18 alkylene group or A-R″′,

wherein:

A is a C 2 -C 18 alkylene group, and

R′″ is selected from —NHC(O)—, —NHC(O)—(CH 2 ) n−1 —, —NHC(O)C(O)—, —NHC(O)(CH 2 ) v C(O)—, —OC(O)—, —OC(O)—(CH 2 ) n−1 —, —OC(O)C(O)—, —OC(O)(CH 2 ) v C(O)—, —OCH 2 CH(OH)CH 2 OC(O)(CH 2 ) n−1 —, and —OCH 2 CH(OH)CH 2 OC(O)(CH 2 ) v C(O)—;

v is an integer selected from 1-12;

T is H, a C 1 -C 4 alkyl radical, or a C 1 -C 4 acyl radical;

x is an integer selected from 1 to 200, and

n is an integer selected from 1 to 6.

5. The radiation-curable silicone composition of claim 1 , wherein the organosiloxane(s) with at least two aliphatic unsaturated carbon-carbon moieties is characterized by the following features alone or in combination:

structure:

wherein R independently represent a non-substituted or substituted, monovalent hydrocarbon group with 1 to about 6 C atoms and wherein n is in the range of 3 to 10,000

viscosity: 1 to 90,000 mPa*s at 23° C.;

amount: being present from 10 to 98 wt. % with respect to the weight of the whole radiation-curable composition.

6. The radiation-curable silicone composition of claim 1 , the organosiloxane(s) with at least two aliphatic unsaturated carbon-carbon moieties comprising a QM resin containing vinyl groups, which is further characterized by the following features alone or in combination:

concentration of unsaturated moieties: at least 0.15 mmol/g;

viscosity: 500 to 90,000 mPa*s at 23° C.;

amount: being present from 10 to 98 wt. % with respect to the weight of the whole radiation-curable composition.

7. The radiation-curable silicone composition of claim 1 , comprising:

an organosiloxane(s) with at least two aliphatic unsaturated carbon-carbon moieties characterized by the following features alone or in combination:

structure:

wherein R independently represent a non-substituted or substituted, monovalent hydrocarbon group with 1 to about 6 C atoms and wherein n is in the range of 3 to 10,000;

viscosity: 1 to 90,000 mPa*s at 23° C.;

amount: being present from 10 to 98 wt. % with respect to the weight of the whole radiation-curable composition; and

an organosiloxane(s) with at least two aliphatic unsaturated carbon-carbon moieties comprising a QM resin containing vinyl groups characterized by the following features alone or in combination:

concentration of unsaturated moieties: at least 0.15 mmol/g;

viscosity: 500 to 90,000 mPa*s at 23° C.;

amount: being present from 10 to 98 wt. % with respect to the weight of the whole radiation-curable composition.

8. The radiation-curable silicone composition of claim 1 , comprising in addition either of the following components alone or in combination:

filler(s) as Component F in an amount of 0.5 to 60 wt. %,

stabilizer(s) as Component G in an amount of 0.001 to 1 wt. %,

wt. % with respect to the whole radiation-curable composition.

9. The radiation-curable silicone composition of claim 1 , wherein:

Component A:

being present in an amount of 0.5 to 50 wt. %,

comprising 7 to 100 mol-% (mercaptoalkyl)methylsiloxane units;

organosiloxane(s) with at least two aliphatic unsaturated carbon-carbon moieties as Component B:

being present in an amount of 10 to 98 wt. %,

having a viscosity of 1 to 90,000 mPa*s,

Component C:

being present in an amount of 0.01 to 5 wt. %,

having a light absorption band in the range of 300 to 450 nm,

Component D:

being present in an amount of 0.001 to 1 wt. %,

having a light absorption maximum in the range of 460 to 600 nm,

having a solubility of less than 1 g in 100 g water at 23° C.,

Component E:

being present in an amount of 0.1 to 15 wt. %,

wt. % with respect to the weight of the whole composition.

10. A process for producing a cured 3-dim article, the process comprising:

providing a radiation-curable silicone composition of claim 1 , and

curing the radiation-curable silicone composition with radiation as part of an additive-manufacturing technique.

11. The process of claim 10 , wherein the radiation curing is carried out within a wavelength range of 350 to 420 nm.

12. A cured 3-dim article obtained by curing the radiation-curable silicone composition of claim 1 with radiation.

13. The cured 3-dim article of claim 12 , being characterized by the following features alone or in combination:

being rubber-elastic;

having a Shore hardness A of 30 to 90 according to DIN/EN 53505 (2000-08);

having a tensile strength of 0.5 to 50 MPa according to DIN/EN 53504 (2017-03);

having an elongation at break of 10 to 1,000% according to DIN/EN 53504 (2017-03).

14. The cured 3-dim article of claim 12 , having the shape of a protection mask, inhaler mask, night guard, mouth guard, respirator, hearing protection, fitting, shock absorber, seal, orthodontic or dental appliances, or part thereof.

15. A kit of parts comprising:

the radiation-curable silicone composition of claim 1 ,

a stereolithographic printer, and

a set of instructions directing a user to process the radiation-curable silicone composition to form a cured 3-dim article.

16. The radiation-curable silicone composition of claim 1 , the dye(s) comprising a perylene moiety.

17. The radiation-curable silicone composition of claim 1 , the dye(s) being selected from:

N,N′-bis (2,6-diisopropylphenyl)-1,6,7,12-tetraphenoxyperylene-3,4:9,10-tetracarboxdiimide; and

anthra[2,1,9-def:6,5,10-d′e′f′]diisoquinoline-1,3,8,10(2H,9H)-tetrone-2,9-bis[2,6-bis(1-methylethyl)phenyl].

18. The radiation-curable silicone composition of claim 1 , the surfactant being selected according to the formula:

wherein:

each R is —CH 3 ,

R 1 is —C 3 H 6 —,

each R 2 is —H,

R 3 is —CH 3 ,

n is an integer selected from 0-1,

m is an integer selected from 0-5,

a is an integer selected from 5-20, and

b is an integer of 0.

19. The radiation-curable silicone composition of claim 18 , the dye(s) comprising a perylene moiety.

20. The radiation-curable silicone composition of claim 19 , comprising:

Component A comprising:

a poly(mercaptopropyl)methylsiloxane characterized by a viscosity of 75-100 mPa*s; and

Component B comprising one or more of:

a VQM resin characterized by:

a concentration of unsaturated moieties: 0.2-0.5 mmol/g, and

a viscosity of 10-12 mPa*s; and

vinyl-terminated polydimethylsiloxane characterized by:

a concentration of unsaturated moieties: 0.07 mmol/g, and

a viscosity of 100 Pa*s.