Low temperature cure silicone elastomer

Patent metadata

Field	Value
Publication number	US-10774184-B2
Application number	US-201716078267-A
Country	US
Kind code	B2
Filing date	Feb 21, 2017
Priority date	Feb 23, 2016
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A liquid curable silicone elastomer composition is disclosed. The liquid curable silicone elastomer composition comprises an organopolysiloxane (A) containing at least two silicon-bonded alkenyl groups per molecule, an organopolysiloxane (B) containing at least two silicon-bonded hydrogen atoms per molecule, a platinum based catalyst (C), an inhibitor (D), and a silica filler (E). The organopolysiloxane (B) is a branched polymer, contains M siloxy units, and the at least two silicon-bonded hydrogen atoms are present on the M siloxy units. The inhibitor (D) is selected from the group consisting of acetylenic alcohols and their derivatives. The inhibitor (D) is present in the liquid curable silicone elastomer composition in an amount to provide a molar ratio of the inhibitor (D) to platinum in the catalyst (C)—of from 150 to 900 (150:1 to 900:1).

First claim

The invention claimed is:

1. A method of forming a three-dimensional (3D) article, the method comprising:
i) printing a first heat-curable silicone composition with a 3D printer to form a layer;
ii) heating the layer to form an at least partially cured layer;
iii) printing a second heat-curable silicone composition on the at least partially cured layer with the 3D printer to form a subsequent layer; and
iv) heating the subsequent layer to form an at least partially cured subsequent layer;
v) optionally, repeating steps iii) and iv) with independently selected heat-curable silicone composition(s) for any additional layer(s) to form the 3D article;
wherein the first and second heat-curable silicone compositions are the same as or different from one another; and
wherein at least one of the first and second heat-curable silicone compositions comprises a liquid curable silicone elastomer composition comprising:
an organopolysiloxane (A) containing at least two silicon-bonded alkenyl groups per molecule;
an organopolysiloxane (B) containing M siloxy units and at least two silicon-bonded hydrogen atoms per molecule, wherein the at least two silicon-bonded hydrogen atoms are present on the M siloxy units of the organopolysiloxane (B), and the organopolysiloxane (B) is a branched polymer;
a platinum based catalyst (C);
an inhibitor (D), wherein the inhibitor (D) is selected from the group consisting of acetylenic alcohols and their derivatives, and is present in the liquid curable silicone elastomer composition in an amount to provide a molar ratio of the inhibitor (D) to platinum in the catalyst (C) of from 150 to 900 (150:1 to 900:1); and
a silica filler (E).

2. The method of claim 1 , wherein the inhibitor (D) contains at least one unsaturated bond.

3. The method of claim 2 , wherein the at least one unsaturated bond of the inhibitor (D) is in a terminal position.

4. The method of claim 1 , wherein the inhibitor (D) is selected from the group consisting of 1-ethynyl-1-cyclohexanol, 2-methyl-3-butyn-2-ol, 3-butyn-1-ol, 3-butyn-2-ol, propargylalcohol, 2-phenyl-2-propyn-1-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclopentanol, 1-phenyl-2-propynol, 3-methyl-1-penten-4-yn-3-ol, and mixtures thereof.

5. The method of claim 1 , wherein the organopolysiloxane (B) is of the general formula (II):
(R 2 HSiO 1/2 ) x (R 3 SiO 1/2 ) y (RHSiO 2/2 ) z (R 2 SiO 2/2 ) p (RSiO 3/2 ) q (HSiO 3/2 ) v (SiO 4/2 ) r   (II);

where each R is independently selected from an aliphatic hydrocarbyl, aromatic hydrocarbyl, or organyl group, H is a hydrogen atom, x≥2, y≥0, z≥0, p≥0, q≥0, v≥0, and r≥0, provided that; when q=0, r>0, when r=0, q>0, and (p+q+r)≥1.

6. The method of claim 5 , wherein x>2, y>0, r>1, and z, p, q, and v=0.

7. The method of claim 1 , wherein the ratio of silicon-bonded hydrogen atoms in organopolysiloxane (B)/alkenyl groups in organopolysiloxane (A) is from 1.1 to 3.5.

8. The method of claim 1 , wherein the silica filler (E) contains at least one alkenyl group on its surface.

9. The method of claim 1 , wherein the liquid curable silicone elastomer composition further comprises an adhesion promoter.

10. The method of claim 1 , wherein the liquid curable silicone elastomer composition is provided in at least two separate parts.

11. The method of claim 1 , wherein heating is further defined as heating at a temperature of from 80 to 140° C.

12. The method of claim 11 , wherein the heating temperature is from 90 to 130° C.

13. The method of claim 1 , comprising step v) wherein steps iii) and iv) are repeated.

14. The method of claim 1 , wherein the first and second heat-curable silicone compositions are the same.

15. The method of claim 1 , wherein the first and second heat-curable silicone compositions are different from one another.

Assignees

• Dow Silicones Corp
• Beyer Patrick
• Hankammer Ivonne
• Wolf Hans Peter

Inventors

• Beyer Patrick
• Hankammer Ivonne
• Wolf Hans Peter

Classifications

• B33Y70/10

  Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L83/04 Primary

  Polysiloxanes · CPC title

• B29C64/124

  using layers of liquid which are selectively solidified · CPC title

• C08K9/06

  with silicon-containing compounds · CPC title