US 11,993,715 B2Granted

Low compression set silicon rubber composition

AssigneeMomentive Performance Materials Inc.

InventorsOliver Safarowsky, Olaf Erdmann

Life of this patent

Estimating the term…

Abstract

The present invention relates to curable silicone rubber composition which can be cured to silicone rubber composition having low compression set and the use of such a curable silicone rubber composition.

Claims22

Dependent claims

A curable silicone rubber composition, which is curable to a cured composition having a compression set value of 30 percent or less after testing at 175° C. for 144 hours, and 50 percent or less-after testing at 175° C. for 1000 hours, when measuring the compression set of the cured silicone rubber compositions in accordance with INTERNATIONAL STANDARD ISO 815-1 First edition 2008-02-01 on a cylindrical disc of diameter 29 mm±0.5 mm and thickness 12.5 mm±0.5 mm, wherein the applied compression is (25±2) % of the original thickness of the test piece, comprising:

A) 100 parts by weight of at least one polyorganosiloxane having at least one alkenyl group R1,
B) 0.01 to 100 parts by weight of at least two different organohydrogensiloxanes having at least two SiH groups, selected from polyorganohydrogensiloxanes of the general formula (2):
[MaDbTcQdZe]m (2)
wherein:
M=R3SiO1/2, and/or M*
D=R2Si2/2, and/or D*
T=RSiO3/2, and/or T*
Q=SiO4/2,
with M*=HR2SiO1/2, D*=HRSiO2/2, T*=HSiO3/2,
Z is a divalent optionally substituted hydrocarbyl bridging group with up to 14 carbon atoms between two siloxy groups, which siloxy groups are as defined before, and
R is independently selected from saturated or aromatic organic groups,
a=0.01-10
b=0-1000
c=0-50
d=0-5
e=0-3
m=1-1000,
with the proviso that there are at least two groups selected from M*, D* and T*,
and wherein:
at least a first of the at least two different organohydrogensiloxanes B) is selected from the group of B1) a resin based organohydrogensiloxane having >2 terminal SiH groups comprising at least one unit selected from T, T* and Q,
and at least a second of the at least two different organohydrogensiloxanes B) is selected from the group of B2) an organohydrogensiloxane having 2 or more SiH groups and being different from B1),
C) at least one transition metal catalyst,
D) 0.01 to 100 parts by weight of at least one reinforcing filler with a BET surface area of at least 50 m2/g based on 100 parts by weight of the total amount of the components A) and B), and
G) optionally up to 100 parts by weight one or more auxiliary additives,
wherein Component A) comprises at least one of component A1), and at least one of component A2), which are defined as follows:
A1) at least one polyorganosiloxane of the formula (Ia),
wherein each R is independently selected from saturated or aromatic organic groups, each R1 is independently selected from alkenyl groups, and x is ≥0,
A2) at least one polyorganosiloxane of the formula (Ib),
wherein x, R and R1 are as defined above;
R2 is selected from R or R1, and y is ≥1, and wherein the molar ratio of the alkenyl groups R1 in component A2) to the alkenyl groups R1 in component A1) is in the range of 0.3 to 8
and wherein the composition satisfies one or more of the following requirements a) to b):
a) the molar ratio of all SiH groups to all groups SiR1 wherein R1 is as defined above in the composition is ≤3;
and
b) the key impact factor KpSiH in mmol/g as defined below is between 2.5 to 17.5 mmol/g;
KpSiH
=
∑
i
⁢
{
[
Parts
⁢
⁢
B
i
*
SiH
⁢
⁢
of
⁢
⁢
B
i
]
*
(
1
-
P
i
⁡
(
D
*
⁢
D
*
)
)
*
(
1
-
2
SiH
⁡
(
B
i
)
*
(
1
-
P
i
⁡
(
D
*
⁢
D
*
)
)
)
}
*
1
SiH
SiR
1
wherein
“parts Bi” are the weight percentages of the i-th component B) based on the total weight of the composition,
“SiH of Bi” is the SiH-content of the i-th component B) in mmol/gram,
“SiH(Bi)” is the number of SiH-groups in the i-th component B) per molecule,
“SiH/SiR1” is as defined under item a) above,
P
i
⁡
(
D
*
⁢
D
*
)
=
[
mol
⁢
⁢
number
⁢
⁢
of
⁢
⁢
D
*
⁢
⁢
groups
mol
⁢
⁢
number
⁢
⁢
of
⁢
⁢
groups
⁢
⁢
(
D
*
+
D
+
M
+
M
*
)
]
2
wherein
D is R2SiO2/2 in component B),
M is R3SiO1/2 in component B),
D* is HRSiO2/2 in component B),
M*=HR2SiO1/2 in component B), wherein R is as defined above, and
Pi (D*D*) for each respective i-th component B), having the required units, is 0 to 1.

163 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/979,609Filed 11 Mar 2019
Priority: EP 1816123612 Mar 2018
Published: US 2021/0040322 A111 Feb 2021
Granted: 28 May 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification17 codes

C08L 83/04
Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with…
C08G 77/12
Polysiloxanes: containing silicon bound to hydrogen
C08G 77/20
Polysiloxanes: containing silicon bound to unsaturated aliphatic groups
C08K 3/013
Characterized by their specific function: fillers, pigments or reinforcing additives

Family

US 2021/0040322 A1Pre-grant publication · published 11 Feb 2021
US 11,993,715 B2This patent

From the US filing history. Foreign family members aren’t listed.

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Abstract

A) 100 parts by weight of at least one polyorganosiloxane having at least one alkenyl group R1,
B) 0.01 to 100 parts by weight of at least two different organohydrogensiloxanes having at least two SiH groups, selected from polyorganohydrogensiloxanes of the general formula (2):
[MaDbTcQdZe]m (2)
wherein:
M=R3SiO1/2, and/or M*
D=R2Si2/2, and/or D*
T=RSiO3/2, and/or T*
Q=SiO4/2,
with M*=HR2SiO1/2, D*=HRSiO2/2, T*=HSiO3/2,
Z is a divalent optionally substituted hydrocarbyl bridging group with up to 14 carbon atoms between two siloxy groups, which siloxy groups are as defined before, and
R is independently selected from saturated or aromatic organic groups,
a=0.01-10
b=0-1000
c=0-50
d=0-5
e=0-3
m=1-1000,
with the proviso that there are at least two groups selected from M*, D* and T*,
and wherein:
at least a first of the at least two different organohydrogensiloxanes B) is selected from the group of B1) a resin based organohydrogensiloxane having >2 terminal SiH groups comprising at least one unit selected from T, T* and Q,
and at least a second of the at least two different organohydrogensiloxanes B) is selected from the group of B2) an organohydrogensiloxane having 2 or more SiH groups and being different from B1),
C) at least one transition metal catalyst,
D) 0.01 to 100 parts by weight of at least one reinforcing filler with a BET surface area of at least 50 m2/g based on 100 parts by weight of the total amount of the components A) and B), and
G) optionally up to 100 parts by weight one or more auxiliary additives,
wherein Component A) comprises at least one of component A1), and at least one of component A2), which are defined as follows:
A1) at least one polyorganosiloxane of the formula (Ia),
wherein each R is independently selected from saturated or aromatic organic groups, each R1 is independently selected from alkenyl groups, and x is ≥0,
A2) at least one polyorganosiloxane of the formula (Ib),
wherein x, R and R1 are as defined above;
R2 is selected from R or R1, and y is ≥1, and wherein the molar ratio of the alkenyl groups R1 in component A2) to the alkenyl groups R1 in component A1) is in the range of 0.3 to 8
and wherein the composition satisfies one or more of the following requirements a) to b):
a) the molar ratio of all SiH groups to all groups SiR1 wherein R1 is as defined above in the composition is ≤3;
and
b) the key impact factor KpSiH in mmol/g as defined below is between 2.5 to 17.5 mmol/g;
KpSiH
=
∑
i
⁢
{
[
Parts
⁢
⁢
B
i
*
SiH
⁢
⁢
of
⁢
⁢
B
i
]
*
(
1
-
P
i
⁡
(
D
*
⁢
D
*
)
)
*
(
1
-
2
SiH
⁡
(
B
i
)
*
(
1
-
P
i
⁡
(
D
*
⁢
D
*
)
)
)
}
*
1
SiH
SiR
1
wherein
“parts Bi” are the weight percentages of the i-th component B) based on the total weight of the composition,
“SiH of Bi” is the SiH-content of the i-th component B) in mmol/gram,
“SiH(Bi)” is the number of SiH-groups in the i-th component B) per molecule,
“SiH/SiR1” is as defined under item a) above,
P
i
⁡
(
D
*
⁢
D
*
)
=
[
mol
⁢
⁢
number
⁢
⁢
of
⁢
⁢
D
*
⁢
⁢
groups
mol
⁢
⁢
number
⁢
⁢
of
⁢
⁢
groups
⁢
⁢
(
D
*
+
D
+
M
+
M
*
)
]
2
wherein
D is R2SiO2/2 in component B),
M is R3SiO1/2 in component B),
D* is HRSiO2/2 in component B),
M*=HR2SiO1/2 in component B), wherein R is as defined above, and
Pi (D*D*) for each respective i-th component B), having the required units, is 0 to 1.

163 more elements

Facts

Application

16/979,609Filed 11 Mar 2019

Priority

EP 1816123612 Mar 2018

Published

US 2021/0040322 A111 Feb 2021

Granted

28 May 2024

Term ends

Not estimatedThe source records don’t support an estimate.

Classification17 codes

C08L 83/04
Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with…
C08G 77/12
Polysiloxanes: containing silicon bound to hydrogen
C08G 77/20
Polysiloxanes: containing silicon bound to unsaturated aliphatic groups
C08K 3/013
Characterized by their specific function: fillers, pigments or reinforcing additives