Curable organopolysiloxane composition for transducers and applications of such curable silicone composition for transducers
View Patent ↗The present invention provides a curable organopolysiloxane composition capable of producing a cured article that can be used as a transducer and provided with excellent mechanical characteristics and/or electrical characteristics. The present invention also relates to a novel curable organopolysiloxane composition for transducer use comprising a curable organopolysiloxane composition and a compound having a highly dielectric functional group.
1. A member for a transducer, the member being formed by at least partial curing of a curable composition comprising:
a curable organopolysiloxane composition (A+B) and
a compound having a highly dielectric functional group, such compound selected from the group consisting of a silicon compound (Z), an organic compound (Z1) having at least one curable functional group, and an organic compound (Z2) miscible with the composition (A+B),
further optionally comprising one or more of
(E) at least one type of inorganic particle selected from the group consisting of electrically conductive inorganic particles, insulating inorganic particles, and reinforcing inorganic particles; and
(F) an additive for improvement of mold releasability or insulation breakdown characteristics.
2. The member according to claim 1 , wherein the curable composition is curable by condensation curing reaction, addition curing reaction, peroxide curing reaction, photo-curing reaction or drying with solvent removal.
3. The member according to claim 1 , wherein the curable composition cure to provide a structure wherein the highly dielectric functional group is bonded to silicon atom via a covalent bond.
4. The member according to claim 1 , wherein the content of the highly dielectric functional group is in a range of 1 to 80 mass % to the entire siloxane component of the curable composition.
5. The member according to claim 1 , wherein the highly dielectric functional group is at least one selected from a) Halogen Atoms, a1) Halogen Atom-containing Groups, b) Nitrogen Atom-containing Groups, c) Oxygen Atom-containing Groups, d) Heterocyclic Groups, e) Boron-containing Groups, f) Phosphorous-containing Groups, and g) Sulfur-containing Groups.
6. The member according to claim 1 , wherein at least one part of main chain of curable organopolysiloxane includes at least one selected from Boron atom and Phosphorous atom.
7. The member according to claim 1 , wherein
the curable composition comprises the curable organopolysiloxane composition (A+B) comprising a) a reactive organopolysiloxane represented by general formula M a M R b D c D R d T e T R f Q g , wherein (a+c)/(b+d+e+f+g) is less than or equal to 3, R represents a reactive group capable of condensation reaction, addition reaction, peroxide reaction, or photoreaction, in an amount range greater than or equal to 0.1% by weight and less than or equal to 25% by weight, relative to the entire organopolysiloxane component in the curable composition;
b) a reactive organopolysiloxane having only at each molecular terminal a group capable of condensation reaction, addition reaction, peroxide reaction, or photoreaction, in an amount greater than or equal to 75% by weight and less than or equal to 99.9% by weight, relative to a total siloxane component in the curable composition
a reactive organopolysiloxane (S)
having in a single molecule at least two groups capable of reacting with each other through condensation reaction, addition reaction, peroxide reaction, or photoreaction to cure the curable composition, wherein the average molecular weight between the 2 groups capable of the curing reaction is less than 10,000; and
d), a reactive organopolysiloxane (L) having in a single molecule at least two groups capable of reacting with each other through a condensation reaction, addition reaction, peroxide reaction, or photoreaction to cure the curable composition, wherein the average molecular weight between the 2 groups capable of the curing reaction is greater than or equal to 10,000 and less than or equal to 150,000; and the weight ratio of the component (S) to the component (L) being in the range of 1:99 to 40:60; and further comprising
(C) a curing agent; and
(D) dielectric inorganic fine particles having a specific dielectric constant at 1 kHz of greater than or equal to 10, at room temperature.
8. The member according to claim 2 , wherein the curing reaction is addition reaction.
9. The member according to claim 2 , wherein the curing reaction is a hydrosilylation reaction.
10. The member according to claim 1 , wherein the ratio of the silicon-bonded hydrogen atoms to silicon-bonded unsaturated hydrocarbon groups in the curable composition is in a range of 0.5:1.0 to 3.0:1.0.
11. The member according to claim 1 , wherein the curable organopolysiloxane composition (A+B) comprises:
(A) an organohydrogenpolysiloxane comprising one or multiple components, represented by general formula M ai M H bi D ci D H di T ei T H fi Q gi , having a number average molecular weight (Mw) in a range of 300 to 15,000, and having at least 2 silicon-bonded hydrogen atoms on average in a single molecule; and
(B) an organopolysiloxane comprising one or multiple components, represented by general formula M aj M Vi bi D ci D Vi dj T ej T Vi fj Q gj , having a number average molecular weight (Mw) in a range of 300 to 100,000, and having at least 2 alkenyl groups on average in a single molecule;
wherein
bonded hydrogen atom; M Vi , D Vi , and T Vi are each a siloxane unit in which one of the R groups of the siloxane units represented by M, D, and T, respectively, is replaced by an alkenyl group of 2 to 20 carbon atoms;
a, b, c, d, e, f, and g is each an average number per single molecule;
i represents an i-th component in the component (A);
j represents a j-th component in the component (B);
and the organopolysiloxane composition (A+B), after curing, contains a crosslinking point count per unit weight in a range of 0.5 to 20 μmol/g, such crosslinking point per unit weight calculated by the following formula:
(
Number
of
cross
link
points
per
unit
weight
)
=
(
The
index
of
number
of
cross
link
points
of
the
reaction
composition
)
(
The
index
of
raw
material
mole
count
in
the
reaction
composition
)
×
(
The
index
of
molecular
weight
of
the
reaction
composition
)
in which:
(i)
(
The
index
of
probability
of
inter
terminal
group
reaction
)
=
(
Σ
i
=
1
p
α
i
Mw
i
b
i
Σ
i
=
1
p
α
i
Mw
i
(
b
i
+
d
i
+
f
i
)
)
×
(
Σ
j
=
1
r
β
j
Mw
j
b
j
Σ
j
=
1
r
β
j
Mw
j
(
b
j
+
d
j
+
f
j
)
)
;
(
The
index
of
number
of
cross
link
points
of
the
reaction
composition
)
=
1
2
×
(
∑
i
=
1
p
α
i
Mw
i
(
b
i
+
d
i
)
+
∑
j
=
1
r
β
j
Mw
j
(
b
j
+
d
j
)
)
+
∑
i
=
1
p
α
i
Mw
i
(
e
i
+
f
i
+
g
i
)
+
∑
j
=
1
r
β
j
Mw
j
(
e
j
+
f
j
+
g
j
)
-
1
2
×
(
The
index
of
probability
of
inter
terminal
group
reaction
)
×
(
∑
i
=
1
p
α
i
Mw
i
(
b
i
+
d
i
+
f
i
)
+
∑
j
=
1
r
β
j
Mw
j
(
b
j
+
d
j
+
f
j
)
)
.
provided that, in a calculation of the index of number of crosslink points of the reaction composition, a component for which a value of (a+c)/(b+d+e+f+g) representing average number of organosiloxane units between reactive groups in a molecular chain is less than 3, is taken to act as a single crosslink point, and calculation for such a component assumes (b+d)=0 and (e+f+g)=1;
(ii)
(
The
index
of
raw
material
mole
count
in
the
reaction
composition
)
=
∑
i
=
1
p
α
i
Mw
i
+
∑
j
=
1
r
β
j
Mw
j
(
The
index
of
molecular
weight
in
the
reaction
composition
)
=
(
Σ
i
=
1
p
α
i
Mw
i
Σ
i
=
1
p
α
i
)
+
(
Σ
j
=
1
r
β
j
Mw
j
Σ
j
=
1
r
β
j
)
where, in each of the formulae,
α i =α w i /γ, wherein α w i is the amount by weight of the i-th component of the component (A) γ=(moles of silicon-bonded hydrogen atoms (H) included in the component (A))/(moles of alkenyl groups (V) included in the component (B));
β j is the amount by weight of the j-th component of the component (B);
M wi is the number average molecular weight of the i-th component of the component (A); and
M wj is the number average molecular weight of the j-th component of the component (B).
12. The member for a transducer according to claim 1 ,
wherein the molecular weight between crosslink points of the reactive polysiloxane after the curing reaction is in a range of 100,000 to 2,000,000, where
(
Molecular
weight
between
cross
link
points
)
=
(
The
index
of
molecular
weight
of
the
reaction
composition
)
×
(
The
index
of
raw
material
mole
count
in
the
reaction
composition
)
(
The
index
of
organosiloxane
chain
count
of
the
reaction
composition
)
;
wherein
(
The
index
of
probability
of
inter
terminal
group
reaction
)
=
(
Σ
i
=
1
p
α
i
Mw
i
b
i
Σ
i
=
1
p
α
i
Mw
i
(
b
i
+
d
i
+
f
i
)
)
×
(
Σ
j
=
1
r
β
j
Mw
j
b
j
Σ
j
=
1
r
β
j
Mw
j
(
b
j
+
d
j
+
f
j
)
)
;
(
The
index
of
organosiloxane
chain
count
of
the
reaction
composition
)
=
∑
i
=
1
p
(
α
i
Mw
i
(
d
i
+
2
e
i
+
2
f
i
+
3
g
i
+
1
)
)
+
∑
j
=
1
r
(
β
j
Mw
j
(
d
j
+
2
e
j
+
2
f
j
+
3
g
j
+
1
)
)
-
1
2
×
(
The
index
of
probability
of
inter
terminal
group
reaction
)
×
(
∑
i
=
1
p
α
i
Mw
i
(
b
i
+
d
i
+
f
i
)
+
∑
j
=
1
r
β
j
Mw
j
(
b
j
+
d
j
+
f
j
)
)
;
provided that, in the calculation of the index of number of crosslink points of the reaction composition, a component for which the value of (a+c)/(b+d+e+f+g) representing average number of organosiloxane units between reactive groups in the molecular chain is less than 3 is taken to act as a single crosslink point, and calculation for such a component assumes (d+2e+2f+3g+1)=0;
(
The
index
of
raw
material
mole
count
in
the
reaction
composition
)
=
∑
i
=
1
p
α
i
Mw
i
+
∑
j
=
1
r
β
j
Mw
j
;
and
(
The
index
of
molecular
weight
in
the
reaction
composition
)
=
(
Σ
i
=
1
p
α
i
Mw
i
Σ
i
=
1
p
α
i
)
+
(
Σ
j
=
1
r
β
j
Mw
j
Σ
j
=
1
r
β
j
)
,
the terms as defined above.
13. The member according to claim 1 ,
wherein the curable organopolysiloxane composition (A+B) comprises:
(A1) at least one type of organohydrogenpolysiloxane having silicon atom-bonded hydrogen atoms at both molecular terminals, a weight fraction of hydrogen atoms being 0.1 to 1.0% by weight;
(A2) at least one type of organohydrogenpolysiloxane having at least 3 silicon atom-bonded hydrogen atoms in a single molecule, a weight fraction of hydrogen atoms being 0.03 to 2.0% by weight; and
(B) at least one type of organopolysiloxane having at least 2 alkenyl groups in a single molecule, a weight fraction of the alkenyl groups being 0.05 to 0.5% by weight; and further comprising
a hydrosilylation reaction catalyst; and
(D) dielectric inorganic fine particles having a specific dielectric constant at 1 kHz greater than or equal to 10 at room temperature.
14. The member according to claim 7 , wherein
the dielectric inorganic fine particles (D) are one or more types of inorganic fine particles selected from the group consisting of titanium oxide, barium titanate, strontium titanate, lead titanate zirconate, and barium titanate, and composite metal oxides in which the barium and titanium positions of barium titanate are partially replaced by an alkaline earth metal.
15. The member according to claim 14 , wherein a part or the entire amount of the components (D) and (E) is surface treated by one or more types of surface treatment agent.
16. A method for production of the curable organopolysiloxane composition for manufacturing the member according to claim 1 , the method comprising a step of blending at least two components constituting the curable organopolysiloxane composition using at least one mechanical means selected from the group consisting of twin screw extruders, twin screw kneaders, and single screw blade-type extruders.
17. The member according to claim 1 , wherein the member is a silicone elastomer intermediate layer.
18. A transducer comprising:
a pair of electrodes;
the silicone elastomer intermediate layer of claim 17 disposed between the electrodes.
19. The transducer of claim 18 having two or more silicone elastomer intermediate layers, wherein at least two of the silicone elastomer intermediate layers are stacked.