U.S. patent application number 14/193333 was filed with the patent office on 2014-06-26 for silicone resin composition, encapsulating layer, reflector, and optical semiconductor device.
This patent application is currently assigned to NITTO DENKO CORPORATION. The applicant listed for this patent is NITTO DENKO CORPORATION. Invention is credited to Haruka FUJII, Hiroyuki KATAYAMA.
Application Number | 20140175494 14/193333 |
Document ID | / |
Family ID | 46262001 |
Filed Date | 2014-06-26 |
United States Patent
Application |
20140175494 |
Kind Code |
A1 |
FUJII; Haruka ; et
al. |
June 26, 2014 |
SILICONE RESIN COMPOSITION, ENCAPSULATING LAYER, REFLECTOR, AND
OPTICAL SEMICONDUCTOR DEVICE
Abstract
A silicone resin composition includes a cage octasilsesquioxane;
a polysiloxane containing alkenyl groups at both ends containing an
alkenyl group having the number of moles smaller than the number of
moles of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; a hydroxyl group-containing polysiloxane,
organohydrogenpolysiloxane, or a polysiloxane containing alkenyl
groups at side chain.
Inventors: |
FUJII; Haruka; (Osaka,
JP) ; KATAYAMA; Hiroyuki; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NITTO DENKO CORPORATION |
Osaka |
|
JP |
|
|
Assignee: |
NITTO DENKO CORPORATION
Osaka
JP
|
Family ID: |
46262001 |
Appl. No.: |
14/193333 |
Filed: |
February 28, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13524236 |
Jun 15, 2012 |
8716412 |
|
|
14193333 |
|
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|
Current U.S.
Class: |
257/98 ; 252/582;
524/862 |
Current CPC
Class: |
C08G 77/045 20130101;
C08G 77/16 20130101; C08L 83/04 20130101; C08L 83/04 20130101; C08G
77/12 20130101; H01L 2924/0002 20130101; C08G 77/20 20130101; H01L
23/296 20130101; H01L 2924/0002 20130101; C08L 83/00 20130101; Y10T
428/31663 20150401; H01L 33/60 20130101; H01L 33/56 20130101; H01L
2924/00 20130101 |
Class at
Publication: |
257/98 ; 524/862;
252/582 |
International
Class: |
H01L 33/56 20060101
H01L033/56; H01L 33/60 20060101 H01L033/60 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 16, 2011 |
JP |
2011-134575 |
Jun 16, 2011 |
JP |
2011-134576 |
Jun 16, 2011 |
JP |
2011-134577 |
Claims
1. A silicone resin composition comprising: a cage
octasilsesquioxane having a group represented by formula (1) below,
a straight chain polysiloxane containing alkenyl groups at both
ends which contains, at both of its molecular ends, an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane, a
hydrosilylation catalyst, and a polysiloxane containing alkenyl
groups at side chain which contains two or more alkenyl groups at
its side chain, ##STR00036## (where R.sup.1 represents a monovalent
hydrocarbon group; R.sup.2 represents hydrogen or a monovalent
hydrocarbon group; the molar ratio of monovalent hydrocarbon
group:hydrogen in R.sup.2 in the cage octasilsesquioxane as a whole
is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).
2. The silicone resin composition according to claim 1, wherein the
cage octasilsesquioxane is represented by formula (2) below,
##STR00037## (where R.sup.1 and R.sup.2 are as defined above; and
the molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
is the same as above).
3. The silicone resin composition according to claim 1, wherein the
polysiloxane containing alkenyl groups at both ends is represented
by formula (3) below: ##STR00038## (where R.sup.3 represents a
monovalent hydrocarbon group; R.sup.4 represents an alkenyl group;
and "a" represents an integer of 1 or more).
4. The silicone resin composition according to claim 1, wherein the
polysiloxane containing alkenyl groups at side chain is represented
by formula (8) below, ##STR00039## (where A to D represent
constituent units; A and D represent terminal units; B and C
represent repeating units; R.sup.5 represents a monovalent
hydrocarbon group; R.sup.6 represents an alkenyl group; "b"
represents 0 or an integer of 1 or more; and "c" represents an
integer of 2 or more).
5. The silicone resin composition according to claim 1, wherein the
polysiloxane containing alkenyl groups at side chain is represented
by formula (9) below, ##STR00040## (where E to H represent
constituent units, E to G represent repeating units; H represents a
terminal unit; R.sup.7 represents a monovalent hydrocarbon group;
"e" represents an integer of 1 or more; "f" and "g" represent 0 or
an integer of 1 or more; "h" represents an integer of 4 or more;
and at least two R.sup.7 groups are alkenyl groups per 1
molecule).
6. The silicone resin composition according to claim 1, comprising
a silicone resin precursor and the polysiloxane containing alkenyl
groups at side chain, wherein the silicone resin precursor is
obtained by allowing the cage octasilsesquioxane to react with the
polysiloxane containing alkenyl groups at both ends in the presence
of the hydrosilylation catalyst.
7. An encapsulating layer used for encapsulating an optical
semiconductor element, wherein the encapsulating layer is formed
from a silicone resin composition, and the silicone resin
composition comprises a cage octasilsesquioxane having a group
represented by formula (1) below, a straight chain polysiloxane
containing alkenyl groups at both ends which contains, at both of
its molecular ends, an alkenyl group having the number of moles
smaller than the number of moles of the hydrosilyl group of the
cage octasilsesquioxane, a hydrosilylation catalyst, and a
polysiloxane containing alkenyl groups at side chain which contains
two or more alkenyl groups at its side chain, ##STR00041## (where
R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
8. An optical semiconductor device comprising an optical
semiconductor element and an encapsulating layer that encapsulates
the optical semiconductor element, wherein the encapsulating layer
is formed from a silicone resin composition, and the silicone resin
composition comprises a cage octasilsesquioxane having a group
represented by formula (1) below, a straight chain polysiloxane
containing alkenyl groups at both ends which contains, at both of
its molecular ends, an alkenyl group having the number of moles
smaller than the number of moles of the hydrosilyl group of the
cage octasilsesquioxane, a hydrosilylation catalyst, and a
polysiloxane containing alkenyl groups at side chain which contains
two or more alkenyl groups at its side chain, ##STR00042## (where
R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
9. A reflector used for reflecting light emitted from an optical
semiconductor element, wherein the reflector is formed from a light
reflective composition containing a silicone resin composition and
a light reflective component, and the silicone resin composition
comprises a cage octasilsesquioxane having a group represented by
formula (1) below, a straight chain polysiloxane containing alkenyl
groups at both ends which contains, at both of its molecular ends,
an alkenyl group having the number of moles smaller than the number
of moles of the hydrosilyl group of the cage octasilsesquioxane, a
hydrosilylation catalyst, and a polysiloxane containing alkenyl
groups at side chain which contains two or more alkenyl groups at
its side chain, ##STR00043## (where R.sup.1 represents a monovalent
hydrocarbon group; R.sup.2 represents hydrogen or a monovalent
hydrocarbon group; and the molar ratio of monovalent hydrocarbon
group:hydrogen in R.sup.2 in the cage octasilsesquioxane as a whole
is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).
10. An optical semiconductor device comprising an optical
semiconductor element and a reflector that reflects light emitted
from the optical semiconductor element, wherein the reflector is
formed from a light reflective composition containing a silicone
resin composition and a light reflective component, and the
silicone resin composition comprises a cage octasilsesquioxane
having a group represented by formula (1) below, a straight chain
polysiloxane containing alkenyl groups at both ends which contains,
at both of its molecular ends, an alkenyl group having the number
of moles smaller than the number of moles of the hydrosilyl group
of the cage octasilsesquioxane, a hydrosilylation catalyst, and a
polysiloxane containing alkenyl groups at side chain which contains
two or more alkenyl groups at its side chain, ##STR00044## (where
R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a divisional of application Ser. No. 13/524,236
filed Jun. 15, 2012, which claims priority from Japanese Patent
Application No. 2011-134575 filed on Jun. 16, 2011, Japanese Patent
Application No. 2011-134576 filed on Jun. 16, 2011, and Japanese
Patent Application No. 2011-134577 filed on Jun. 16, 2011, the
contents of which are hereby incorporated by reference into this
application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a silicone resin
composition, an encapsulating layer, a reflector, and an optical
semiconductor device, in particular to a silicone resin
composition, an encapsulating layer composed of the silicone resin
composition, a reflector containing the silicone resin composition,
and an optical semiconductor device including these.
[0004] 2. Description of Related Art
[0005] Conventionally, a silicone resin excellent in transparency
has been used as an encapsulating material for encapsulating
optical semiconductor elements such as a light-emitting diode
(LED). Such a silicone resin is liquid at room temperature. The
silicone resin is applied to an optical semiconductor element, and
then cured by heating, thereby encapsulating an optical
semiconductor element.
[0006] Furthermore, in view of storage stability and handleability,
a silicone resin that is solid at room temperature is also used. As
such a solid silicone resin, for example, Japanese Unexamined
Patent Publication No. 2000-154252 has proposed a
silsesquioxane-containing polymer obtained by allowing
pentacyclo[9.5.1.1.sup.3.90.1.sup.5.150.1.sup.7.13]octasiloxane to
react with 1,3-divinyltetramethyldisiloxane.
[0007] Also, Japanese Unexamined Patent Publication No. 2002-69191
has proposed a polysiloxane obtained by allowing hydrogenated
octasilsesquioxane to react with disilanol.
[0008] The encapsulating materials proposed in Japanese Unexamined
Patent Publication No. 2000-154252 and Japanese Unexamined Patent
Publication No. 2002-69191 are plasticized by heating, thereby
encapsulating optical semiconductor elements.
SUMMARY OF THE INVENTION
[0009] However, in view of improving heat resistance and
durability, it has been desired that a solid silicone resin is
plasticized by heating, and then cured. However, the encapsulating
materials of Japanese Unexamined Patent Publication No. 2000-154252
and Japanese Unexamined Patent Publication No. 2002-69191 are
disadvantageous in that they cannot be cured.
[0010] Furthermore, it has been desired that the silicone resin is
cured at a comparatively low temperature.
[0011] Meanwhile, an improvement in flexibility of encapsulating
materials is desired in order to prevent damages to optical
semiconductor elements.
[0012] An object of the present invention is to provide a silicone
resin composition that has excellent transparency and heat
resistance, has both thermoplastic and thermosetting properties,
achieves a decreased thermosetting temperature, and has excellent
flexibility; an encapsulating layer composed of the silicone resin
composition; a reflector containing the silicone resin composition;
and an optical semiconductor device including these.
[0013] The first invention group is as follows.
[0014] A silicone resin composition of the present invention
contains a cage octasilsesquioxane having a group represented by
formula (1) below; an alkenyl group-containing polysiloxane
containing an alkenyl group having the number of moles smaller than
the number of moles of the hydrosilyl group of the cage
octasilsesquioxane; a hydrosilylation catalyst; and a hydroxyl
group-containing polysiloxane,
##STR00001##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0015] In the silicone resin composition of the present invention,
it is preferable that the cage octasilsesquioxane is represented by
formula (2) below:
##STR00002##
(where R.sup.1 and R.sup.2 are as defined above; and the molar
ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 is the
same as above).
[0016] In the silicone resin composition of the present invention,
it is preferable that the alkenyl group-containing polysiloxane is
represented by formula (3) below:
##STR00003##
(where R.sup.3 represents a monovalent hydrocarbon group; R.sup.4
represents an alkenyl group; and "a" represents an integer of 1 or
more).
[0017] In the silicone resin composition of the present invention,
it is preferable that the hydroxyl group-containing polysiloxane is
represented by formula (4) below:
##STR00004##
(where R.sup.5 represents a monovalent hydrocarbon group; and "b"
represents an integer of 1 or more).
[0018] It is preferable that the silicone resin composition of the
present invention includes a silicone resin precursor and the
hydroxyl group-containing polysiloxane, wherein the silicone resin
precursor is obtained by allowing the cage octasilsesquioxane to
react with the alkenyl group-containing polysiloxane in the
presence of the hydrosilylation catalyst.
[0019] An encapsulating layer of the present invention is an
encapsulating layer used for encapsulating an optical semiconductor
element, wherein the encapsulating layer is formed from a silicone
resin composition, and the silicone resin composition contains a
cage octasilsesquioxane having a group represented by formula (1)
below; an alkenyl group-containing polysiloxane containing an
alkenyl group having the number of moles smaller than the number of
moles of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a hydroxyl group-containing
polysiloxane,
##STR00005##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0020] An optical semiconductor device of the present invention
includes an optical semiconductor element, and an encapsulating
layer that encapsulates the optical semiconductor element, wherein
the encapsulating layer is formed from a silicone resin
composition, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below;
an alkenyl group-containing polysiloxane containing an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a hydroxyl group-containing
polysiloxane,
##STR00006##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0021] A reflector of the present invention is a reflector used for
reflecting light emitted from an optical semiconductor element,
wherein the reflector is formed from a light reflective composition
containing a silicone resin composition and a light reflective
component, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below;
an alkenyl group-containing polysiloxane containing an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a hydroxyl group-containing
polysiloxane,
##STR00007##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0022] An optical semiconductor device of the present invention
includes an optical semiconductor element and a reflector that
reflects light emitted from the optical semiconductor element,
wherein the reflector is formed from a light reflective composition
containing a silicone resin composition and a light reflective
component, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below;
an alkenyl group-containing polysiloxane containing an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a hydroxyl group-containing
polysiloxane,
##STR00008##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0023] The silicone resin composition in the first invention group
of the present invention has a molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 in a specific range, and
therefore in the cage octasilsesquioxane, the proportion of the
hydrosilyl group to be reacted with the alkenyl group of the
alkenyl group-containing polysiloxane is adjusted. Moreover, the
alkenyl group-containing polysiloxane is allowed to react with the
cage octasilsesquioxane so that the number of moles of the alkenyl
group is smaller than the number of moles of the hydrosilyl group
of the cage octasilsesquioxane. Therefore, the obtained silicone
resin composition has excellent transparency and heat resistance,
and can have both thermoplastic and thermosetting properties.
[0024] Furthermore, the silicone resin composition contains a
hydroxyl group-containing polysiloxane, and therefore the hydroxyl
group in the hydroxyl group-containing polysiloxane is allowed to
react with the residual hydrosilyl group in the cage
octasilsesquioxane, thereby allowing improvement in flexibility of
the silicone resin composition.
[0025] Furthermore, the silicone resin composition achieves a
decreased thermosetting temperature.
[0026] Thus, the encapsulating layer of the present invention
composed of the above-described silicone resin composition in the
first invention group is plasticized by heating at the time of
encapsulation, and thereafter is cured at low temperature, thereby
allowing encapsulation of the optical semiconductor element while
preventing damages effectively.
[0027] In the optical semiconductor device in the first invention
group of the present invention, the optical semiconductor element
is encapsulated by the above-described encapsulating layer, and
therefore has excellent optical properties and heat resistance, and
also has excellent reliability, mechanical strength, and
durability.
[0028] The reflector of the present invention containing the
above-described silicone resin composition in the first invention
group has excellent heat resistance, flexibility, and thermoplastic
and thermosetting properties.
[0029] Thus, the optical semiconductor device of the present
invention including the above-described reflector in the first
invention group has excellent optical properties and heat
resistance, and also has excellent flexibility, mechanical
strength, and durability.
[0030] The second invention group is as follows.
[0031] A silicone resin composition of the present invention
contains a cage octasilsesquioxane having a group represented by
formula (1) below, an alkenyl group-containing polysiloxane
containing an alkenyl group having the number of moles smaller than
the number of moles of the hydrosilyl group of the cage
octasilsesquioxane, a hydrosilylation catalyst, and
organohydrogenpolysiloxane,
##STR00009##
(where R.sup.1 represents a monovalent hydrocarbon group selected
from a saturated hydrocarbon group and an aromatic hydrocarbon
group; R.sup.2 represents hydrogen or a monovalent hydrocarbon
group selected from a saturated hydrocarbon group and an aromatic
hydrocarbon group; and the molar ratio of monovalent hydrocarbon
group:hydrogen in R.sup.2 in the cage octasilsesquioxane as a whole
is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).
[0032] In the silicone resin composition of the present invention,
it is preferable that the cage octasilsesquioxane is represented by
formula (2) below,
##STR00010##
(where R.sup.1 and R.sup.2 are as defined above; and the molar
ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 is the
same as the above).
[0033] In the silicone resin composition of the present invention,
it is preferable that the alkenyl group-containing polysiloxane is
represented by formula (3) below,
##STR00011##
(where R.sup.3 represents a monovalent hydrocarbon group selected
from a saturated hydrocarbon group and an aromatic hydrocarbon
group; R.sup.4 represents an alkenyl group; and "a" represents an
integer of 1 or more).
[0034] In the silicone resin composition of the present invention,
it is preferable that the organohydrogenpolysiloxane is a
side-chain type organohydrogenpolysiloxane represented by formula
(5) below;
##STR00012##
(where A to D represent constituent units; A and D represent
terminal units; B and C represent repeating units; R.sup.5
represents a monovalent hydrocarbon group selected from a saturated
hydrocarbon group and an aromatic hydrocarbon group; "b" represents
0 or an integer of 1 or more; and "c" represents an integer of 1 or
more) and/or, a both-ends type organohydrogenpolysiloxane
represented by formula (6) below,
##STR00013##
(where E to H represent constituent units; E and H represent
terminal units; F and G represent repeating units; R.sup.6
represents a monovalent hydrocarbon group selected from a saturated
hydrocarbon group and an aromatic hydrocarbon group; "d" represents
an integer of 0 or more; and "e" represents an integer of 0 or
more).
[0035] It is preferable that the silicone resin composition of the
present invention contains a silicone resin precursor obtained by
allowing the cage octasilsesquioxane and the alkenyl
group-containing polysiloxane to react in the presence of the
hydrosilylation catalyst; and the organohydrogenpolysiloxane.
[0036] An encapsulating layer of the present invention is an
encapsulating layer used for encapsulating an optical semiconductor
element, wherein the encapsulating layer is formed from a silicone
resin composition, and the silicone resin composition contains a
cage octasilsesquioxane having a group represented by formula (1)
below, an alkenyl group-containing polysiloxane containing an
alkenyl group having the number of moles smaller than the number of
moles of the hydrosilyl group of the cage octasilsesquioxane, a
hydrosilylation catalyst, and organohydrogenpolysiloxane,
##STR00014##
(where R.sup.1 represents a monovalent hydrocarbon group selected
from a saturated hydrocarbon group and an aromatic hydrocarbon
group; R.sup.2 represents hydrogen or a monovalent hydrocarbon
group selected from a saturated hydrocarbon group and an aromatic
hydrocarbon group; and the molar ratio of monovalent hydrocarbon
group:hydrogen in R.sup.2 in the cage octasilsesquioxane as a whole
is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).
[0037] An optical semiconductor device of the present invention
includes an optical semiconductor element and an encapsulating
layer that encapsulates the optical semiconductor element, wherein
the encapsulating layer is formed from a silicone resin
composition, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below,
an alkenyl group-containing polysiloxane containing an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane, a
hydrosilylation catalyst, and organohydrogenpolysiloxane,
##STR00015##
(where R.sup.1 represents a monovalent hydrocarbon group selected
from a saturated hydrocarbon group and an aromatic hydrocarbon
group; R.sup.2 represents hydrogen or a monovalent hydrocarbon
group selected from a saturated hydrocarbon group and an aromatic
hydrocarbon group; the molar ratio of monovalent hydrocarbon
group:hydrogen in R.sup.2 in the cage octasilsesquioxane as a whole
is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).
[0038] A reflector of the present invention is a reflector used for
reflecting light emitted from an optical semiconductor element,
wherein the reflector is formed from a light reflective composition
containing a silicone resin composition and a light reflective
component, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below,
an alkenyl group-containing polysiloxane containing an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane, a
hydrosilylation catalyst, and organohydrogenpolysiloxane,
##STR00016##
(where R.sup.1 represents a monovalent hydrocarbon group selected
from a saturated hydrocarbon group and an aromatic hydrocarbon
group; R.sup.2 represents hydrogen or a monovalent hydrocarbon
group selected from a saturated hydrocarbon group and an aromatic
hydrocarbon group; and the molar ratio of monovalent hydrocarbon
group:hydrogen in R.sup.2 in the cage octasilsesquioxane as a whole
is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).
[0039] An optical semiconductor device of the present invention
includes an optical semiconductor element and a reflector that
reflects light emitted from the optical semiconductor element,
wherein the reflector is formed from a light reflective composition
containing a silicone resin composition and a light reflective
component, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below,
an alkenyl group-containing polysiloxane containing an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane, a
hydrosilylation catalyst, and organohydrogenpolysiloxane,
##STR00017##
(where R.sup.1 represents a monovalent hydrocarbon group selected
from a saturated hydrocarbon group and an aromatic hydrocarbon
group; R.sup.2 represents hydrogen or a monovalent hydrocarbon
group selected from a saturated hydrocarbon group and an aromatic
hydrocarbon group; and the molar ratio of monovalent hydrocarbon
group:hydrogen in R.sup.2 in the cage octasilsesquioxane as a whole
is, as an average value, in a range of 6.5:1.5 to 5.5:2.5).
[0040] The silicone resin composition of the present invention in
the second invention group has a molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 in a specific range, and
therefore in the cage octasilsesquioxane, the proportion of the
hydrosilyl group to be reacted with the alkenyl group of the
alkenyl group-containing polysiloxane is adjusted. Moreover, the
alkenyl group-containing polysiloxane is allowed to react with the
cage octasilsesquioxane so that the number of moles of the alkenyl
group is smaller than the number of moles of the hydrosilyl group
of the cage octasilsesquioxane. Therefore, the obtained silicone
resin composition has excellent transparency and heat resistance,
and can have both thermoplastic and thermosetting properties.
[0041] Furthermore, the silicone resin composition contains
organohydrogenpolysiloxane, and therefore the hydrosilyl group in
the organohydrogenpolysiloxane can be allowed to react with the
residual hydrosilyl group in the cage octasilsesquioxane, thereby
allowing improvement in flexibility of the silicone resin
composition.
[0042] Furthermore, the silicone resin composition achieves a
decreased thermosetting temperature.
[0043] Thus, the encapsulating layer of the present invention
composed of the above-described silicone resin composition in the
second invention group is plasticized by heating at the time of
encapsulation, and thereafter is cured at low temperature, thereby
allowing encapsulation of the optical semiconductor element while
preventing damages effectively.
[0044] In the optical semiconductor device of the present invention
in the second invention group, the optical semiconductor element is
encapsulated by the above-described encapsulating layer, and
therefore has excellent optical properties and heat resistance, and
also has excellent reliability, mechanical strength, and
durability.
[0045] The reflector of the present invention containing the
above-described silicone resin composition in the second invention
group has excellent heat resistance, flexibility, thermoplastic
properties, and thermosetting properties.
[0046] The optical semiconductor device of the present invention
including the above-described reflector in the second invention
group has excellent optical properties and heat resistance, and
also has excellent flexibility, mechanical strength, and
durability.
[0047] The third invention group is as follows.
[0048] A silicone resin composition of the present invention
contains a cage octasilsesquioxane having a group represented by
formula (1) below; a straight chain polysiloxane containing alkenyl
groups at both ends which contains, at both of its molecular ends,
an alkenyl group having the number of moles smaller than the number
of moles of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a polysiloxane containing alkenyl
groups at side chain which contains two or more alkenyl groups at
its side chain,
##STR00018##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0049] In the silicone resin composition of the present invention,
it is preferable that the cage octasilsesquioxane is represented by
formula (2) below,
##STR00019##
(where R.sup.1 and R.sup.2 are as defined above, and the molar
ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 is the
same as above).
[0050] In the silicone resin composition of the present invention,
it is preferable that the polysiloxane containing alkenyl groups at
both ends is represented by formula (3) below:
##STR00020##
(where R.sup.3 represents a monovalent hydrocarbon group; R.sup.4
represents an alkenyl group; and "a" represents an integer of 1 or
more).
[0051] In the silicone resin composition of the present invention,
it is preferable that the polysiloxane containing alkenyl groups at
side chain is represented by formula (8) below,
##STR00021##
(where A to D represent constituent units; A and D represent
terminal units; B and C represent repeating units; R.sup.5
represents a monovalent hydrocarbon group; R.sup.6 represents an
alkenyl group; "b" represents 0 or an integer of 1 or more; and "c"
represents an integer of 2 or more).
[0052] In the silicone resin composition of the present invention,
it is preferable that the polysiloxane containing alkenyl groups at
side chain is represented by formula (9) below,
##STR00022##
(where E to H represent constituent units; E to G represent
repeating units; H represents a terminal unit; R.sup.7 represents a
monovalent hydrocarbon group; "e" represents an integer of 1 or
more; "f" and "g" represent 0 or an integer of 1 or more; "h"
represents an integer of 4 or more; and at least two R.sup.7 groups
are alkenyl groups per 1 molecule).
[0053] It is preferable that the silicone resin composition of the
present invention contains a silicone resin precursor obtained by
allowing the cage octasilsesquioxane to react with the polysiloxane
containing alkenyl groups at both ends in the presence of the
hydrosilylation catalyst; and the polysiloxane containing alkenyl
groups at side chain.
[0054] An encapsulating layer of the present invention is an
encapsulating layer used for encapsulating an optical semiconductor
element, wherein the encapsulating layer is formed from a silicone
resin composition, and the silicone resin composition contains a
cage octasilsesquioxane having a group represented by formula (1)
below; a straight chain polysiloxane containing alkenyl groups at
both ends which contains, at both of its molecular ends an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a polysiloxane containing alkenyl
groups at side chain which contains two or more alkenyl groups at
its side chain,
##STR00023##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0055] An optical semiconductor device of the present invention
includes an optical semiconductor element and an encapsulating
layer that encapsulates the optical semiconductor element, wherein
the encapsulating layer is formed from a silicone resin
composition, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below;
a straight chain polysiloxane containing alkenyl groups at both
ends which contains, at both of its molecular ends, an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a polysiloxane containing alkenyl
groups at side chain which contains two or more alkenyl groups at
its side chain,
##STR00024##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0056] A reflector of the present invention is a reflector used for
reflecting light emitted from an optical semiconductor element,
wherein the reflector is formed from a light reflective composition
containing a silicone resin composition and a light reflective
component, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below;
a straight chain polysiloxane containing alkenyl groups at both
ends which contains, at both of its molecular ends, an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a polysiloxane containing alkenyl
groups at side chain which contains two or more alkenyl groups at
its side chain,
##STR00025##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0057] An optical semiconductor device of the present invention
includes an optical semiconductor element and a reflector that
reflects light emitted from the optical semiconductor element,
wherein the reflector is formed from a light reflective composition
containing a silicone resin composition and a light reflective
component, and the silicone resin composition contains a cage
octasilsesquioxane having a group represented by formula (1) below;
a straight chain polysiloxane containing alkenyl groups at both
ends which contains, at both of its molecular ends, an alkenyl
group having the number of moles smaller than the number of moles
of the hydrosilyl group of the cage octasilsesquioxane; a
hydrosilylation catalyst; and a polysiloxane containing alkenyl
groups at side chain which contains two or more alkenyl groups at
its side chain,
##STR00026##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0058] The silicone resin composition of the present invention in
the third invention group has a molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 in a specific range, and
therefore in the cage octasilsesquioxane, the proportion of the
hydrosilyl group to be reacted with the alkenyl group of the
polysiloxane containing alkenyl groups at both ends is adjusted.
Moreover, the polysiloxane containing alkenyl groups at both ends
is allowed to react with the cage octasilsesquioxane so that the
number of moles of the alkenyl group is smaller than the number of
moles of the hydrosilyl group of the cage octasilsesquioxane.
Therefore, the obtained silicone resin composition has excellent
transparency and heat resistance, and can have both thermoplastic
and thermosetting properties.
[0059] Furthermore, the silicone resin composition contains a
polysiloxane containing alkenyl groups at side chain, and therefore
the alkenyl group of the polysiloxane containing alkenyl groups at
side chain is allowed to react with the residual hydrosilyl group
in the cage octasilsesquioxane, thereby allowing improvement in
flexibility of the silicone resin composition.
[0060] Furthermore, the silicone resin composition achieves a
decreased thermosetting temperature.
[0061] Thus, the encapsulating layer of the present invention
formed from the above-described silicone resin composition in the
third invention group is allowed to plasticize by heating at the
time of encapsulation, and thereafter is cured at low temperature,
thereby allowing encapsulation of the optical semiconductor element
while preventing damages effectively.
[0062] In the optical semiconductor device of the present invention
in the third invention group, the optical semiconductor element is
encapsulated by the above-described encapsulating layer, and
therefore has excellent optical properties and heat resistance, and
also has excellent reliability, mechanical strength, and
durability.
[0063] The reflector of the present invention formed from the light
reflective composition containing the above-described silicone
resin composition in the third invention group has excellent heat
resistance, flexibility, thermoplastic properties, and
thermosetting properties.
[0064] Thus, the optical semiconductor device of the present
invention including the above-described reflector in the third
invention group has excellent optical properties and heat
resistance, and also has excellent flexibility, mechanical
strength, and durability.
BRIEF DESCRIPTION OF THE DRAWINGS
[0065] FIG. 1 shows a cross-sectional view of an optical
semiconductor device in an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0066] In the following, the first embodiment to the third
embodiment corresponding to the first to third invention groups,
which are related to each other, are described in sequence
respectively.
First Embodiment
[0067] A silicone resin composition of the present invention
contains a cage octasilsesquioxane, an alkenyl group-containing
polysiloxane, a hydrosilylation catalyst, and a hydroxyl
group-containing polysiloxane.
[0068] The cage octasilsesquioxane is an octamer of trifunctional
silicone monomer, and to be specific, has eight of the group
represented by formula (1) below,
##STR00027##
(where R.sup.1 represents a monovalent hydrocarbon group; R.sup.2
represents hydrogen or a monovalent hydrocarbon group; and the
molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2 in
the cage octasilsesquioxane as a whole is, as an average value, in
a range of 6.5:1.5 to 5.5:2.5).
[0069] To be more specific, the cage octasilsesquioxane is
represented by formula (2) below:
##STR00028##
(where R.sup.1 and R.sup.2 are as defined above and the molar ratio
of monovalent hydrocarbon group:hydrogen in R.sup.2 is as defined
above).
[0070] In the above-described formulas (1) and (2), a monovalent
hydrocarbon group represented by R.sup.1 is, for example, a
saturated hydrocarbon group or an aromatic hydrocarbon group.
[0071] Examples of saturated hydrocarbon groups include straight
chain saturated hydrocarbon groups (e.g., an alkyl group having 1
to 6 carbon atoms such as methyl, ethyl, propyl, butyl, pentyl, and
hexyl), branched saturated hydrocarbon groups (e.g., an alkyl group
having 3 to 6 carbon atoms such as isopropyl and isobutyl), and
cyclic saturated hydrocarbon groups (e.g., a cycloalkyl group
having 3 to 6 carbon atoms such as cyclohexyl). Examples of
aromatic hydrocarbon groups include an aryl group having 6 to 8
carbon atoms such as phenyl, benzyl, and toluoyl.
[0072] The number of carbon atoms in the monovalent hydrocarbon
group is, for example, 1 to 8, preferably 1 to 6.
[0073] R.sup.1 may be the same or different. Preferably, R.sup.1 is
the same.
[0074] Preferably, in view of easy preparation and thermal
stability, a straight chain saturated hydrocarbon group, more
preferably an alkyl group having 1 to 6 carbon atoms, and
particularly preferably methyl is used as the monovalent
hydrocarbon group.
[0075] In the above-described formulas (1) and (2), examples of a
monovalent hydrocarbon group represented by R.sup.2 include the
above-described monovalent hydrocarbon group represented by
R.sup.1. Preferably, methyl is used.
[0076] The molar ratio of monovalent hydrocarbon group:hydrogen in
R.sup.2 in formula (2) is, in the cage octasilsesquioxane as a
whole, in the range of 6.5:1.5 to 5.5:2.5, preferably 6.0:2.0 to
5.5:2.5 as an average value.
[0077] That is, in one molecule of the cage octasilsesquioxane, the
group represented by the above-described formula (1) forms 1.5 to
2.5 (to be specific, two), preferably 2 to 2.5 (to be specific,
two) of hydrosilyl groups (--SiH).
[0078] When the above-described molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 is more than 6.5/1.5
(=6.5:1.5) (for example, when the molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 is 7/1 (=7:1)), the number of
moles of the hydrosilyl group is significantly small, and therefore
the reaction degree of the cage octasilsesquioxane relative to the
alkenyl group-containing polysiloxane and/or the hydroxyl
group-containing polysiloxane is decreased significantly, causing a
low molecular weight of the obtained silicone resin composition,
and a solid silicone resin composition cannot be obtained.
[0079] On the other hand, when the above-described molar ratio of
monovalent hydrocarbon group:hydrogen in R.sup.2 is below 5.5/2.5
(=5.5:2.5) (for example, when the molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 is 5/3 (=5:3)), the number of
moles of the hydrosilyl group of the cage octasilsesquioxane is
excessively high, and therefore the reaction degree of the cage
octasilsesquioxane relative to the alkenyl group-containing
polysiloxane and/or the hydroxyl group-containing polysiloxane is
excessively increased, and the silicone resin composition does not
exhibit thermoplastic properties.
[0080] Examples of the above-described cage octasilsesquioxane
include, to be specific, a cage octasilsesquioxane having methyl in
R.sup.1 and methyl or hydrogen in R.sup.2 in the above-described
formulas (1) and (2), and having a molar ratio of methyl:hydrogen
in R.sup.2 in the cage octasilsesquioxane as a whole, as an average
value, of 5.5:2.5, 6:2, or 6.5:1.5.
[0081] The cage octasilsesquioxane represented by the
above-described formula (2) is synthesized, for example, by a known
method (in accordance with e.g., Japanese Unexamined Patent
Publication No. 2007-246880).
[0082] To be specific, tetraalkoxysilane (tetraethoxysilane, etc.)
is allowed to react with alcohol such as methanol and/or water in
the presence of a catalyst to synthesize an octa (silsesquioxane)
skeleton (portion excluding formula (1) in formula (2)), and
thereafter, dialkylchlorosilane (dimethylchlorosilane, etc.) and
trialkylchlorosilane (trimethylchlorosilane, etc.) are blended at
the mixing ratio corresponding to the above-described molar ratio
of monovalent hydrocarbon group:hydrogen in R.sup.2, allowing the
alkoxyl group (ethoxy, etc.) bonded to the silicon atom in the octa
(silsesquioxane) skeleton to react with dialkylchlorosilane and
trialkylchlorosilane. After the reaction, as necessary, the
reactant is purified. The cage octasilsesquioxane can be obtained
in this manner.
[0083] A commercially available product can also be used as the
cage octasilsesquioxane.
[0084] The alkenyl group-containing polysiloxane is a polysiloxane
containing an alkenyl group, for example, a straight chain
polysiloxane containing alkenyl groups at both of its molecular
ends (polysiloxane containing alkenyl groups at both ends), and to
be specific, is represented by formula (3) below,
##STR00029##
(where R.sup.3 represents a monovalent hydrocarbon group; R.sup.4
represents an alkenyl group; and "a" represents an integer of 1 or
more).
[0085] The monovalent hydrocarbon group represented by R.sup.3 in
formula (3) may be the same or different, and preferably the
same.
[0086] Examples of the monovalent hydrocarbon group represented by
R.sup.3 include the above-described examples of the monovalent
hydrocarbon group represented by R.sup.1 in formulas (1) and (2).
Preferable examples are methyl and phenyl, and a more preferable
example is methyl.
[0087] Examples of the alkenyl group represented by R.sup.4 in
formula (3) include substituted or unsubstituted alkenyl group. A
preferable example is an unsubstituted alkenyl group.
[0088] An example of such an alkenyl group includes an alkenyl
group having 2 to 10 carbon atoms such as vinyl, allyl, propenyl,
butenyl, and pentenyl.
[0089] The number of carbon atoms of the alkenyl group is, for
example, 2 to 10, or preferably 2 to 5.
[0090] R.sup.4 may be the same or different. Preferably, R.sup.4 is
the same.
[0091] Examples of the alkenyl group is, preferably, in view of
reactivity of the cage octasilsesquioxane with the hydrosilyl
group, an alkenyl group having 2 to 5 carbon atoms, and more
preferably vinyl.
[0092] In view of reactivity and stability, "a" is preferably an
integer of 1 to 5000, more preferably an integer of 1 to 1000.
Also, in view of reactivity and stability, "a" is preferably, an
integer of 1 to 100, more preferably an integer of 1 to 50.
[0093] The number average molecular weight of the alkenyl
group-containing polysiloxane represented by the above-described
formula (3) is, in view of safety and handleability, for example,
100 to 10000, preferably 300 to 5000. Also, the number average
molecular weight of the alkenyl group-containing polysiloxane
represented by the above-described formula (3) is, in view of
stability and handleability, for example, 100 to 8000, preferably
300 to 5000. The number average molecular weight is determined by
gel permeation chromatography (GPC: calibrated with polystyrene
standards).
[0094] The alkenyl group-containing polysiloxane represented by the
above-described formula (3) is synthesized in accordance with, for
example, a known method. Alternatively, a commercially available
product (e.g., manufactured by Gelest, Inc.) can also be used.
[0095] Examples of the hydrosilylation catalyst include platinum
catalysts such as platinum black, platinum chloride, chloroplatinic
acid, a platinum olefin complex, a platinum carbonyl complex, and
platinum acetyl acetate; palladium catalysts; and rhodium
catalysts.
[0096] Of these hydrosilylation catalysts, preferably, in view of
compatibility and transparency, a platinum catalyst, more
preferably a platinum olefin complex, to be specific, a
platinum-divinylsiloxane complex such as a
platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex is
used.
[0097] The hydrosilylation catalyst may be prepared as a solution
in a known solvent (such as toluene).
[0098] The hydroxyl group-containing polysiloxane is, for example,
a polysiloxane containing a plurality of (e.g., two) hydroxyl
groups, to be more specific, a both-ends polysiloxane which
contains hydroxyl groups at both ends of its molecule. To be
specific, the hydroxyl group-containing polysiloxane is represented
by formula (4) below,
##STR00030##
(where R.sup.5 represents a monovalent hydrocarbon group and "b"
represents an integer of 1 or more).
[0099] The monovalent hydrocarbon group represented by R.sup.5 in
formula (4) may be the same or different, and preferably the
same.
[0100] Examples of the monovalent hydrocarbon group represented by
R.sup.5 include the above-described examples of the monovalent
hydrocarbon group represented by R.sup.1 in formulas (1) and (2).
Preferable examples are methyl and phenyl, and a more preferable
example is methyl.
[0101] In view of reactivity and stability, "b" is preferably an
integer of 1 to 10000, more preferably an integer of 1 to 5000, and
in view of obtaining a silicone resin composition that is solid at
room temperature, while imparting flexibility, particularly
preferably, "b" represents an integer larger than that of "a", and
most preferably, "b" represents an integer of 100 to 3000.
[0102] The number average molecular weight of the hydroxyl
group-containing polysiloxane represented by the above-described
formula (4) is, in view of safety and handleability, for example,
100 to 100000, preferably 500 to 50000. The number average
molecular weight is determined by gel permeation chromatography
(GPC: calibrated with polystyrene standards).
[0103] The hydroxyl group-containing polysiloxane represented by
the above-described formula (4) is synthesized in accordance with,
for example, a known method. Alternatively, a commercially
available product (e.g., manufactured by Gelest, Inc.) can also be
used.
[0104] The silicone resin composition of the present invention is
prepared by blending cage octasilsesquioxane, an alkenyl
group-containing polysiloxane, a hydrosilylation catalyst, and a
hydroxyl group-containing polysiloxane.
[0105] The mixing ratio of the cage octasilsesquioxane relative to
the silicone resin composition is, for example, 10 to 80 mass %,
preferably 10 to 70 mass %.
[0106] The mixing ratio of the alkenyl group-containing
polysiloxane is prepared so that the number of moles of the alkenyl
group of the alkenyl group-containing polysiloxane is smaller than
the number of moles of the hydrosilyl group of the cage
octasilsesquioxane.
[0107] That is, the molar ratio of the alkenyl group to the
hydrosilyl group (number of moles of the alkenyl group/number of
moles of the hydrosilyl group) is below 1, for example, 0.10 to
0.99, preferably 0.20 to 0.99, more preferably 0.50 to 0.99.
[0108] When the above-described molar ratio is more than the
above-described range, the hydrosilyl group becomes fewer than the
alkenyl group, and in such a case, after the reaction, surplus
hydrosilyl groups do not remain sufficiently, and thermosetting
properties cannot be imparted to the silicone resin
composition.
[0109] On the other hand, when the above-described molar ratio is
below the above-described range, hydrosilyl groups may remain
excessively, and cage octasilsesquioxanes may be cured by
hydrolysis between each other due to moisture in the air and by
self-condensation, thus, flexibility may not be achieved.
[0110] The mixing ratio of the hydrosilylation catalyst (solid
content) relative to 100 parts by mass of the total amount of cage
octasilsesquioxane and alkenyl group-containing polysiloxane is,
for example, 1.0.times.10.sup.-10 to 3 parts by mass, or preferably
1.0.times.10.sup.-8 to 1 part by mass.
[0111] The mixing ratio of the hydroxyl group-containing
polysiloxane is adjusted so that the molar ratio (X/Y) (number of
moles (X) of the hydroxyl group relative to the number of moles (Y)
subtracting the number of moles of the alkenyl group of the alkenyl
group-containing polysiloxane from the number of moles of the
hydrosilyl group of the cage octasilsesquioxane) is, for example,
0.001 to 1000, preferably 0.01 to 100. In other words, the mixing
ratio of the hydroxyl group-containing polysiloxane relative to 100
parts by mass of the total of the cage octasilsesquioxane and the
alkenyl group-containing polysiloxane is, for example, 0.1 to 50
parts by mass, preferably 1 to 30 parts by mass.
[0112] To prepare the silicone resin composition, preferably, a
silicone resin precursor obtained by allowing the cage
octasilsesquioxane and the alkenyl group-containing polysiloxane to
react in the presence of a hydrosilylation catalyst, and a hydroxyl
group-containing polysiloxane are blended.
[0113] That is, first, a cage octasilsesquioxane is allowed to
react with the alkenyl group-containing polysiloxane in the
presence of a hydrosilylation catalyst so that the number of moles
of the hydrosilyl group of the cage octasilsesquioxane is larger
(in excess) than the number of moles of the alkenyl group of the
alkenyl group-containing polysiloxane, thereby producing a silicone
resin precursor.
[0114] To obtain the silicone resin precursor, to be more specific,
the above-described cage octasilsesquioxane and the alkenyl
group-containing polysiloxane are blended at the above-described
mixing ratio along with a hydrosilylation catalyst, and as
necessary, a solvent, and thereafter, as necessary, the mixture is
heated.
[0115] Examples of solvents include aromatic hydrocarbons such as
toluene, aliphatic hydrocarbons such as hexane, and esters such as
ethyl acetate. Preferably, in view of improving compatibility
between the components, aromatic hydrocarbon is used, more
preferably toluene is used.
[0116] The reaction temperature is, for example, 0 to 100.degree.
C., or preferably 20 to 80.degree. C., and the reaction time is,
for example, 0.5 to 96 hours.
[0117] In this manner, cage octasilsesquioxane is allowed to react
with the alkenyl group-containing polysiloxane. That is, the
hydrosilyl group of the cage octasilsesquioxane and the alkenyl
group of the alkenyl group-containing polysiloxane undergo
hydrosilylation reaction.
[0118] The degree of hydrosilylation reaction between the
hydrosilyl group of the cage octasilsesquioxane and the alkenyl
group of the alkenyl group-containing polysiloxane can be checked
by .sup.1H-NMR measurement based on the signal intensity of the
alkenyl group of the alkenyl group-containing polysiloxane, and the
hydrosilylation reaction is regarded as terminated when the signal
disappeared.
[0119] In the above-described hydrosilylation reaction, cage
octasilsesquioxane is allowed to react with the alkenyl
group-containing polysiloxane so that the number of moles of the
hydrosilyl group is in excess compared with the number of moles of
the alkenyl group, and after the reaction, the excess portion of
the hydrosilyl group remains.
[0120] The silicone resin precursor is obtained in this manner.
[0121] The silicone resin precursor is liquid or semi-solid.
[0122] Then, the obtained silicone resin precursor and the hydroxyl
group-containing polysiloxane are blended at the above-described
ratio. By heating (described later) thereafter, the silicone resin
precursor is allowed to react with the hydroxyl group-containing
polysiloxane. As necessary, the solvent was distilled off.
[0123] The silicone resin composition of the present invention can
be obtained in this manner.
[0124] To the silicone resin composition, additives such as the
following can be added at an appropriate proportion to the extent
that does not damage the excellent effects of the present
invention: for example, antioxidants, modifiers, surfactants, dyes,
pigments, discoloration inhibitors, ultraviolet absorbers, fillers,
and phosphors.
[0125] The obtained silicone resin composition is solid. Due to
steric hindrance of the cage octasilsesquioxane, the mobility of
the alkenyl group-containing polysiloxane is reduced, and therefore
a silicone resin composition in solid state can be obtained.
[0126] In the silicone resin composition of the present invention,
the molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
is in a specific range, and therefore in the cage
octasilsesquioxane, the proportion of the hydrosilyl group to be
reacted with the alkenyl group of the alkenyl group-containing
polysiloxane is adjusted. Moreover, the alkenyl group-containing
polysiloxane is allowed to react with cage octasilsesquioxane so
that the alkenyl group thereof has the number of moles that is
smaller than the number of moles of the hydrosilyl group of the
cage octasilsesquioxane. Therefore, the obtained silicone resin
composition has excellent transparency and heat resistance, and at
the same time, can have both thermoplastic and thermosetting
properties.
[0127] That is, the silicone resin composition is once plasticized
(or liquefied) by the above-described heating, and thereafter,
cured by heat.
[0128] Thermoplastic properties of the silicone resin composition
are exhibited when the cage octasilsesquioxane and the alkenyl
group-containing polysiloxane are heated and their mobility is
increased.
[0129] The thermoplastic temperature of the silicone resin
composition is, for example, 40 to 150.degree. C., preferably 50 to
100.degree. C. The thermoplastic temperature is a temperature at
which the silicone resin composition exhibits thermoplastic
properties, to be specific, a temperature at which a solid silicone
resin composition is softened by heating and becomes liquid
completely, and is substantially the same as the softening
temperature.
[0130] The once plasticized silicone resin composition exhibits
thermosetting properties, to be specific, by reaction between the
hydrosilyl group remaining in the silicone resin precursor and the
hydroxyl group in the hydroxyl group-containing polysiloxane.
[0131] To be more specific, the hydrosilyl group of the cage
octasilsesquioxane in the silicone resin precursor undergoes
condensation reaction with the hydroxyl group of the hydroxyl
group-containing polysiloxane.
[0132] The thermosetting temperature of the silicone resin
composition is relatively low, for example, 100 to 250.degree. C.,
preferably 120 to 250.degree. C. The thermosetting temperature is a
temperature at which the silicone resin composition exhibits
thermosetting properties, to be specific, a temperature at which
the plasticized silicone resin composition is cured by heating and
becomes solid completely.
[0133] The silicone resin composition contains a hydroxyl
group-containing polysiloxane, and therefore the hydroxyl group of
the hydroxyl group-containing polysiloxane is allowed to react with
the residual hydrosilyl group in the cage octasilsesquioxane, and
such reaction allows crosslinking to the cage octasilsesquioxane.
Therefore, improvement in flexibility of the silicone resin
composition can be achieved.
[0134] Furthermore, the silicone resin composition achieves a
decreased thermosetting temperature (e.g., 100 to 250.degree.
C.).
[0135] In the above-described embodiment, first, the silicone resin
precursor is obtained, and thereafter, the silicone resin precursor
and the hydroxyl group-containing polysiloxane are blended, thereby
preparing a silicone resin composition, but the preparation method
of the silicone resin composition is not limited thereto. The
silicone resin composition can also be prepared by, for example, by
blending at once cage octasilsesquioxane, an alkenyl
group-containing polysiloxane, a hydrosilylation catalyst, and a
hydroxyl group-containing polysiloxane, and as necessary, heating
the mixture.
[0136] The silicone resin composition can be used, without
limitation, for example, as an encapsulating material and a filler
material for various industrial products. The silicone resin
composition can be formed, preferably, as an encapsulating layer
for various industrial products, to be specific, as an
encapsulating layer for encapsulating an optical semiconductor
element.
[0137] The optical semiconductor element is not particularly
limited, as long as the optical semiconductor element is an element
provided in an optical semiconductor device, and examples thereof
include a light-emitting diode (LED), a photodiode, a
phototransistor, and a laser diode. A preferable example is an LED,
a more preferable example is an LED for lighting.
[0138] FIG. 1 shows a cross-sectional view for illustrating an
embodiment of the optical semiconductor device of the present
invention.
[0139] Next, an embodiment of the optical semiconductor device of
the present invention is described with reference to FIG. 1.
[0140] In FIG. 1, an optical semiconductor device 11 includes a
substrate 3; an optical semiconductor element 1 mounted on the
substrate 3; a housing 2 formed on the substrate 3; an
encapsulating layer 7 that encapsulates the optical semiconductor
element 1; and a phosphor layer 8 formed on the encapsulating layer
7.
[0141] The substrate 3 is formed into a flat plate, and is formed
from, for example, a known insulating resin such as polyimide
resin.
[0142] On the top face of the substrate 3, although not shown in
FIG. 1, a substrate-side terminal is formed for electrically
connecting with an element-side terminal of the optical
semiconductor element 1.
[0143] The optical semiconductor element 1 is mounted on the
substrate 3, and is formed from a known semiconductive
material.
[0144] The optical semiconductor element 1 is flip-chip mounted on
or wire bonded to the substrate 3 by electrically connecting the
element-side terminal and the substrate-side terminal of the
substrate 3.
[0145] The housing 2 is generally frame-shaped when viewed from the
top, and formed into a generally trapezoid tube, with its width
gradually narrowed upward. The housing 2 is disposed to be spaced
apart from the optical semiconductor element 1, so as to encircle
the optical semiconductor element 1.
[0146] The housing 2 is formed from a sintered compact of a ceramic
material containing a light reflective component, and serves as a
reflector which reflects light emitted from the optical
semiconductor element 1.
[0147] The encapsulating layer 7 fills inside the housing 2, to be
specific, covers the top face of the substrate 3 exposed from the
optical semiconductor element 1, and the top face and side face of
the optical semiconductor element 1, in the housing 2.
[0148] The encapsulating layer 7 is formed so that the top face
thereof is flush with the top face of the housing 2 in the
thickness direction (direction perpendicular to the surface
direction).
[0149] The phosphor layer 8 is formed on the entire top face of the
encapsulating layer 7. The phosphor layer 8 is formed also on the
inner end portion of the top face of the housing 2.
[0150] The phosphor layer 8 is formed from, for example, a resin
composition containing phosphor particles (e.g., YAG
(yttrium.aluminum.garnet):Ce, etc.). The phosphor layer 8 can also
be formed from a ceramic phosphor, and sintering the ceramic
phosphor.
[0151] To obtain the optical semiconductor device 11, first, a
substrate 3 is prepared, and then an optical semiconductor element
1 is mounted on the substrate 3: a housing 2 is formed separately
on the substrate 3.
[0152] Then, the housing 2 is filled with the encapsulating layer
7. To be specific, the housing 2 is filled with the above-described
silicone resin composition, and thereafter, as necessary the
solvent is distilled off, and then the provided silicone resin
composition is heated at the above-described temperature.
[0153] Then, the silicone resin composition is once plasticized (or
liquefied) by the above-described heating, thereby encapsulating
the optical semiconductor element 1, and thereafter, cured.
[0154] Thereafter, a phosphor layer 8 is formed on the
encapsulating layer 7.
[0155] An optical semiconductor device 11 is obtained in this
manner.
[0156] Then, because the encapsulating layer 7 is composed of the
above-described silicone resin composition, by being plasticized by
heating at the time of encapsulation and then being cured at low
temperature, the optical semiconductor element 1 can be
encapsulated while effectively preventing damages from impacts or
overheating.
[0157] In the above-described optical semiconductor device 11, the
optical semiconductor element 1 is encapsulated by the
above-described encapsulating layer 7, and therefore has excellent
optical properties and heat resistance, and also has excellent
reliability, mechanical strength, and durability.
[0158] Furthermore, although in the embodiment of FIG. 1, the
encapsulating layer 7 is formed from the silicone resin composition
of the present invention, the housing 2 can also be formed from the
silicone resin composition of the present invention.
[0159] In FIG. 1, the housing 2 as a reflector is formed from a
light reflective composition containing a silicone resin
composition and a light reflective component.
[0160] The light reflective component is, for example, a white
compound, and examples of such a white compound include, to be
specific, a white pigment.
[0161] Examples of white pigments include white inorganic pigments,
and examples of such white inorganic pigments include oxides such
as titanium oxide, zinc oxide, and zirconium oxide; carbonates such
as white lead (lead carbonate), and calcium carbonate; and clay
minerals such as kaolin (kaolinite).
[0162] The white inorganic pigment is preferably oxide, more
preferably titanium oxide.
[0163] With titanium oxide, characteristics such as high whiteness,
high light reflectivity, excellent hiding properties (hiding
power), excellent colorability, high dispersiveness, excellent
weather resistance, and high chemical stability can be
obtained.
[0164] Such a titanium oxide is, to be specific, TiO.sub.2
(titanium oxide (IV), titanium dioxide).
[0165] The crystal structure of titanium oxide is not particularly
limited, and examples thereof include rutile, brookite, and
anatase. Preferably, the crystal structure of titanium oxide is
rutile.
[0166] The crystal system of the titanium oxide is not particularly
limited, and examples thereof include the tetragonal system and the
rhombic system. Preferably, the crystal system of the titanium
oxide is the tetragonal system.
[0167] When the crystal structure and the crystal system of
titanium oxide is rutile and tetragonal system, respectively, even
if the housing 2 is exposed to high temperature for a long period
of time, reduction in light (to be specific, visible light, in
particular, light at wavelengths around 450 nm) reflectance can be
prevented effectively.
[0168] The light reflective component is particulate, and its shape
is not limited, including, for example, spherical, plate-like, and
needle-like shapes. The average value of the maximum length of the
light reflective component (when spherical, the average particle
size) is, for example, 1 to 1000 nm. The average value of the
maximum length of is measured by using a laser
diffraction/scattering particle size distribution analyzer.
[0169] The mixing ratio of the light reflective component relative
to 100 parts by mass of the silicone resin composition is, for
example, 0.5 to 90 parts by mass, preferably, in view of
colorability, light reflectivity, and handleability of the light
reflective composition, 1.5 to 70 parts by mass.
[0170] The above-described light reflective component is dispersed
and mixed homogeneously in the silicone resin composition.
[0171] The light reflective composition is prepared by blending the
above-described silicone resin composition and a light reflective
component, and mixing the mixture homogeneously.
[0172] The housing 2 is formed from the above-described light
reflective composition by being molded into the above-described
shape, and then heated. Also, the above-described silicone resin
composition is contained. The housing 2 has excellent heat
resistance, flexibility, thermoplastic and thermosetting
properties.
[0173] Therefore, the optical semiconductor device 11 including the
above-described housing 2 has excellent optical properties and heat
resistance, while at the same time has excellent flexibility,
mechanical strength, and durability.
[0174] Furthermore, in the optical semiconductor device 11 shown in
FIG. 1, the encapsulating layer 7 is formed from the silicone resin
composition, and at the same time, the housing 2 can also be formed
from the light reflective composition containing the silicone resin
composition.
[0175] In this embodiment, operational advantages described above
can be achieved.
Second Embodiment
[0176] The silicone resin composition of the present invention
contains a cage octasilsesquioxane, an alkenyl group-containing
polysiloxane, a hydrosilylation catalyst, and
organohydrogenpolysiloxane.
[0177] Examples of cage octasilsesquioxanes include those cage
octasilsesquioxanes given as examples in the first embodiment.
[0178] When the above-described molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 in formulas (1) and (2) is
more than 6.5/1.5 (=6.5:1.5) (for example, when the molar ratio of
monovalent hydrocarbon group:hydrogen in R.sup.2 in formulas (1)
and (2) is 7/1 (=7:1)), the number of moles of the hydrosilyl group
is significantly small, and therefore the reaction degree of the
cage octasilsesquioxane relative to the alkenyl group-containing
polysiloxane (and organohydrogenpolysiloxane) is decreased
significantly, leading to a low molecular weight of the obtained
silicone resin composition, and a failure to obtain a solid
silicone resin composition.
[0179] On the other hand, when the above-described molar ratio of
monovalent hydrocarbon group:hydrogen in R.sup.2 is below 5.5/2.5
(=5.5:2.5) (for example, when the molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 is 5/3 (=5:3)), the number of
moles of the hydrosilyl group of the cage octasilsesquioxane is
excessively high, and therefore, the reaction degree of the cage
octasilsesquioxane relative to the alkenyl group-containing
polysiloxane (and organohydrogenpolysiloxane) is increased
excessively, and therefore the silicone resin composition does not
exhibit thermoplastic properties.
[0180] Examples of alkenyl group-containing polysiloxanes include
those alkenyl group-containing polysiloxanes given as examples in
the first embodiment.
[0181] Examples of hydrosilylation catalysts include those
hydrosilylation catalysts given as examples in the first
embodiment.
[0182] Organohydrogenpolysiloxane is a polysiloxane containing a
hydrosilyl group (--SiH). To be more specific,
organohydrogenpolysiloxane is a side-chain type
organohydrogenpolysiloxane which has a straight chain and contains
a hydrosilyl group at a side chain bonded to a main chain; and/or a
both-ends type organohydrogenpolysiloxane which contains hydrosilyl
groups at both of its molecular ends.
[0183] The side-chain type organohydrogenpolysiloxane is, for
example, represented by formula (5) below:
##STR00031##
(where A to D represent constituent units, A and D represent
terminal units; B and C represent repeating units; R.sup.5
represents a monovalent hydrocarbon group selected from a saturated
hydrocarbon group and an aromatic hydrocarbon group; "b" represents
an integer of 0 or more; and "c" represents an integer of 1 or
more).
[0184] A to D constitute a side-chain type
organohydrogenpolysiloxane.
[0185] The monovalent hydrocarbon group represented by R.sup.5 in
formula (5) may be the same or different, and preferably the
same.
[0186] Examples of the monovalent hydrocarbon group represented by
R.sup.5 include the above-described examples of the monovalent
hydrocarbon group represented by R.sup.1 in formulas (1) and (2).
Preferable examples are methyl and phenyl, and a more preferable
example is methyl.
[0187] In view of reactivity and stability, "b" is preferably an
integer of 1 to 10000, more preferably an integer of 1 to 5000. "c"
is preferably 2 or more, and also is, in view of reactivity and
stability, preferably an integer of 1 to 10000, more preferably an
integer of 1 to 1000, and in view of obtaining a silicone resin
composition that is solid at room temperature, while imparting
flexibility, particularly preferably, an integer larger than "a",
most preferably an integer of 100 to 1000.
[0188] Examples of side-chain type organohydrogenpolysiloxanes
include methylhydrogensiloxane,
dimethylsiloxane-CO-methylhydrogensiloxane, ethylhydrogensiloxane,
and methylhydrogensiloxane-CO-methylphenylsiloxane.
[0189] The number average molecular weight of the side-chain type
organohydrogenpolysiloxane is, in view of stability and
handleability, for example, 200 to 100000, preferably 200 to 80000.
The number average molecular weight is determined by gel permeation
chromatography (GPC: calibrated with polystyrene standards).
[0190] The both-ends type organohydrogenpolysiloxane is, for
example, represented by formula (6) below,
##STR00032##
(where E to H represent constituent units; E and H represent
terminal units; F and G represent repeating units; R.sup.6
represents a monovalent hydrocarbon group selected from a saturated
hydrocarbon group and an aromatic hydrocarbon group; "d" represents
an integer of 0 or more; and "e" represents an integer of 0 or
more).
[0191] E to H constitute a both-ends type
organohydrogenpolysiloxane.
[0192] The monovalent hydrocarbon group represented by R.sup.6 in
formula (6) may be the same or different, and preferably the
same.
[0193] Examples of the monovalent hydrocarbon group represented by
R.sup.6 include the above-described examples of the monovalent
hydrocarbon group represented by R.sup.1 in formulas (1) and (2).
Preferable examples of monovalent hydrocarbon groups are a methyl
group, a phenyl group, and a more preferable is a methyl group.
[0194] In view of reactivity and stability, "d" is, preferably, an
integer of 0 or more, more preferably an integer of 1 to 10000,
particularly preferably an integer of 1 to 5000.
[0195] In view of reactivity and stability, "e" is preferably, an
integer of 0 or more, more preferably an integer of 1 to 10000,
particularly preferably an integer of 1 to 5000.
[0196] The both-ends type organohydrogenpolysiloxane is, for
example, when "e" is 1 or more, a hydrogen side chain-both ends
coexisting organopolysiloxane which contains hydrogen atoms at its
side chain branched from the main chain and at both ends of the
main chain; to be specific, examples thereof include hydrosilyl
group-terminated (both ends) methylhydrogenpolysiloxane, hydrosilyl
group-terminated (both ends)
(dimethylpolysiloxane-co-methylhydrogenpolysiloxane), hydrosilyl
group-terminated (both ends) ethylhydrogenpolysiloxane, and
hydrosilyl group-terminated (both ends)
(methylhydrogenpolysiloxane-co-methylphenylpolysiloxane).
[0197] The both-ends type organohydrogenpolysiloxane is, for
example, when "e" is 0, a non-side chain
hydrogen/hydrogen-terminated (both ends) organopolysiloxane which
does not contain hydrogen atoms at its side chain branched from the
main chain but contains hydrogen atoms at both ends of the main
chain; to be specific, examples thereof include hydrosilyl
group-terminated (both ends) polydimethylsiloxane, hydrosilyl
group-terminated (both ends) polymethylphenylsiloxane, and
hydrosilyl group-terminated (both ends) polydiphenylsiloxane.
[0198] Examples of both-ends type organohydrogenpolysiloxanes
include, preferably, a non-side chain hydrogen/hydrogen-terminated
(both ends) organopolysiloxane represented by formula (7):
##STR00033##
(where R.sup.6 represents a monovalent hydrocarbon group selected
from a saturated hydrocarbon group and an aromatic hydrocarbon
group; and "d" represents an integer of 1 or more).
[0199] In formula (7), R.sup.6 is as defined above, and "d" is an
integer of 1 to 10000, preferably an integer of 1 to 5000.
[0200] The number average molecular weight of the both-ends type
organohydrogenpolysiloxane is, in view of stability and/or
handleability, for example, 100 to 1,000,000, more preferably 100
to 100,000. The number average molecular weight is determined by
gel permeation chromatography (GPC: calibrated with polystyrene
standards).
[0201] Such organo hydrogen siloxanes may be used singly, or can be
used in combination.
[0202] The viscosity (25.degree. C.) of organo hydrogen siloxane
is, for example, 10 to 100,000 mPas, preferably 20 to 50,000 mPas.
The viscosity can be measured by using a type B viscometer.
[0203] In organohydrogenpolysiloxane, the hydrosilyl group content
is, to be specific, for example, 0.01 to 20 mmol/g, preferably 0.05
to 15 mmol/g. The hydrosilyl group content is calculated from the
integrated values of the hydrosilyl group and the methyl group
using .sup.1H-NMR.
[0204] Organohydrogenpolysiloxane is synthesized in accordance
with, for example, a known method. Alternatively, a commercially
available product (e.g., manufactured by Gelest, Inc., Shin-Etsu
Chemical Co., Ltd.) can also be used.
[0205] The silicone resin composition of the present invention is
prepared by blending a cage octasilsesquioxane, an alkenyl
group-containing polysiloxane, a hydrosilylation catalyst, and
organohydrogenpolysiloxane.
[0206] The mixing ratio of the cage octasilsesquioxane relative to
the silicone resin composition is, for example, 10 to 80 mass %,
preferably 10 to 70 mass %.
[0207] The mixing ratio of the alkenyl group-containing
polysiloxane is adjusted so that the number of moles of the alkenyl
group of the alkenyl group-containing polysiloxane is smaller than
the number of moles of the hydrosilyl group of the cage
octasilsesquioxane.
[0208] That is, the molar ratio of the alkenyl group to the
hydrosilyl group (number of moles of the alkenyl group/number of
moles of the hydrosilyl group) is below 1, for example, 0.10 to
0.99, preferably 0.20 to 0.99, more preferably 0.50 to 0.99.
[0209] When the above-described molar ratio is more than the
above-described range, the hydrosilyl group is fewer than the
alkenyl group, and in such a case, after the reaction, surplus
hydrosilyl groups do not remain sufficiently, and thermosetting
properties cannot be imparted to the silicone resin
composition.
[0210] On the other hand, when the above-described molar ratio is
below the above-described range, hydrosilyl groups may remain
excessively, and cage octasilsesquioxanes may be cured by
hydrolysis between each other due to moisture in the air and by
self-condensation, thus, flexibility may not be achieved.
[0211] The mixing ratio of the hydrosilylation catalyst (solid
content) relative to 100 parts by mass of the total amount of cage
octasilsesquioxane and alkenyl group-containing polysiloxane is,
for example, 1.0.times.10.sup.-10 to 3 parts by mass, or preferably
1.0.times.10.sup.-8 to 1 part by mass.
[0212] The mixing ratio of organohydrogenpolysiloxane is adjusted
so that a molar ratio (X/Y) (number of moles (X) of the hydrosilyl
group relative to the number of moles (Y) subtracting the number of
moles of the alkenyl group of the alkenyl group-containing
polysiloxane from the number of moles of the hydrosilyl group of
the cage octasilsesquioxane) is, for example, 0.001 to 1000,
preferably 0.01 to 100. In other words, the mixing ratio of
organohydrogenpolysiloxane relative to 100 parts by mass of a total
amount of cage octasilsesquioxane and the alkenyl group-containing
polysiloxane is, for example, 0.01 to 100 parts by mass, preferably
0.01 to 50 parts by mass.
[0213] The mixing ratio of organohydrogenpolysiloxane relative to
the silicone resin composition as a whole is, for example, 0.01 to
50 mass %, preferably 0.01 to 30 mass %.
[0214] To prepare the silicone resin composition, preferably, a
silicone resin precursor obtained by allowing a cage
octasilsesquioxane and an alkenyl group-containing polysiloxane to
react in the presence of a hydrosilylation catalyst, and
organohydrogenpolysiloxane are blended.
[0215] That is, first, a cage octasilsesquioxane is allowed to
react with an alkenyl group-containing polysiloxane in the presence
of a hydrosilylation catalyst at a mixing ratio such that the
number of moles of the hydrosilyl group of the cage
octasilsesquioxane is larger (in excess) than the number of moles
of the alkenyl group of the alkenyl group-containing polysiloxane,
thereby producing a silicone resin precursor.
[0216] To obtain the silicone resin precursor, to be more specific,
the above-described cage octasilsesquioxane and the alkenyl
group-containing polysiloxane are blended at the above-described
mixing ratio along with a hydrosilylation catalyst, and as
necessary, a solvent, and thereafter, as necessary, the mixture is
heated.
[0217] Examples of solvents include aromatic hydrocarbons such as
toluene, aliphatic hydrocarbons such as hexane, and esters such as
ethyl acetate. Preferably, in view of compatibility among
components, aromatic hydrocarbon, more preferably, toluene is
used.
[0218] The reaction temperature is, for example, 0 to 100.degree.
C., or preferably 20 to 80.degree. C., and the reaction time is,
for example, 0.5 to 96 hours.
[0219] In this manner, cage octasilsesquioxane is allowed to react
with the alkenyl group-containing polysiloxane. That is, the
hydrosilyl group of the cage octasilsesquioxane and the alkenyl
group of the alkenyl group-containing polysiloxane undergo
hydrosilylation reaction.
[0220] The degree of hydrosilylation reaction between the
hydrosilyl group of the cage octasilsesquioxane and the alkenyl
group of the alkenyl group-containing polysiloxane can be checked
by .sup.1H-NMR measurement based on the signal intensity of the
alkenyl group of the alkenyl group-containing polysiloxane, and the
hydrosilylation reaction is regarded as terminated when the signal
disappeared.
[0221] In the above-described hydrosilylation reaction, cage
octasilsesquioxane is allowed to react with the alkenyl
group-containing polysiloxane so that the number of moles of the
hydrosilyl group is in excess compared with the number of moles of
the alkenyl group, and after the reaction, the excess portion of
the hydrosilyl group remains.
[0222] The silicone resin precursor is obtained in this manner.
[0223] The silicone resin precursor is liquid or semi-solid.
[0224] Then, the obtained silicone resin precursor and
organohydrogenpolysiloxane are blended at the above-described
ratio. By heating (described later) thereafter, the silicone resin
precursor is allowed to react with the organohydrogenpolysiloxane.
As necessary, the solvent was distilled off.
[0225] The silicone resin composition of the present invention can
be obtained in this manner.
[0226] To the silicone resin composition, for example, those
additives given as examples in the first embodiment can be added at
an appropriate proportion to the extent that does not damage the
excellent effects of the present invention.
[0227] The obtained silicone resin composition is solid. Due to
steric hindrance of the cage octasilsesquioxane, the mobility of
the alkenyl group-containing polysiloxane is reduced, and therefore
a silicone resin composition in solid state can be obtained.
[0228] In the silicone resin composition of the present invention,
the molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
is in a specific range, and therefore in the cage
octasilsesquioxane, the proportion of the hydrosilyl group to be
reacted with the alkenyl group of the alkenyl group-containing
polysiloxane is adjusted. Moreover, the alkenyl group-containing
polysiloxane is allowed to react with the cage octasilsesquioxane
so that the alkenyl group thereof has the number of moles that is
smaller than the number of moles of the hydrosilyl group of the
cage octasilsesquioxane. Therefore, the obtained silicone resin
composition has excellent transparency and heat resistance, and at
the same time, can have both thermoplastic and thermosetting
properties.
[0229] That is, the silicone resin composition is once plasticized
(or liquefied) by the above-described heating, and thereafter,
cured by heat.
[0230] Thermoplastic properties of the silicone resin composition
are exhibited when the cage octasilsesquioxane and the alkenyl
group-containing polysiloxane are heated and their mobility is
increased.
[0231] The thermoplastic temperature of the silicone resin
composition is, for example, 40 to 150.degree. C., preferably 50 to
100.degree. C. The thermoplastic temperature is a temperature at
which the silicone resin composition exhibits thermoplastic
properties, to be specific, a temperature at which a solid silicone
resin composition is softened by heating and becomes liquid
completely, and is substantially the same as the softening
temperature.
[0232] The once plasticized silicone resin composition exhibits
thermosetting properties, to be specific, by reaction of the
hydrosilyl group remained in the silicone resin precursor and the
hydrosilyl group in the organohydrogenpolysiloxane.
[0233] To be more specific, the hydrosilyl group of the cage
octasilsesquioxane in the silicone resin precursor and the
hydrosilyl group in the organohydrogenpolysiloxane are allowed to
react with atmospheric moisture (hydrolysis), and subjected to
dehydration (intermolecule dehydration) condensation reaction.
[0234] The thermosetting temperature of the silicone resin
composition is relatively low, for example, 100 to 250.degree. C.,
preferably 120 to 250.degree. C. Thermal curing temperature is a
temperature at which the silicone resin composition exhibits
thermosetting properties, to be specific, a temperature at which
the plasticized silicone resin composition is cured by heating and
becomes solid completely.
[0235] In the silicone resin composition, the hydrosilyl group in
the organohydrogenpolysiloxane is allowed to react with the
residual hydrosilyl group in the cage octasilsesquioxane. That is,
the dehydration (intermolecule dehydration) condensation reaction
allows crosslinking to cage octasilsesquioxane. Therefore,
improvement in flexibility of the silicone resin composition can be
achieved.
[0236] Furthermore, the silicone resin composition achieves a
decreased thermosetting temperature (e.g., 100 to 250.degree.
C.).
[0237] In the above-described embodiment, first, the silicone resin
precursor is obtained, and thereafter, the silicone resin precursor
and organohydrogenpolysiloxane are blended, thereby preparing a
silicone resin composition, but the preparation method of the
silicone resin composition is not limited thereto. The silicone
resin composition can also be prepared by, for example, by blending
at once cage octasilsesquioxane, the alkenyl group-containing
polysiloxane, the hydrosilylation catalyst, and
organohydrogenpolysiloxane; and as necessary, heating the
mixture.
[0238] The silicone resin composition can be used, without
limitation, for example, as an encapsulating material and a filler
material for various industrial products. The silicone resin
composition can be formed, preferably, as an encapsulating layer
for various industrial products, to be specific, as an
encapsulating layer for encapsulating an optical semiconductor
element.
[0239] The optical semiconductor element is not particularly
limited, as long as the optical semiconductor element is an element
provided in an optical semiconductor device, and examples thereof
include a light-emitting diode (LED), a photodiode, a
phototransistor, and a laser diode. A preferable example is an LED,
a more preferable example is an LED for lighting.
[0240] Next, an embodiment of the optical semiconductor device of
the present invention is described with reference to FIG. 1.
[0241] In FIG. 1, an optical semiconductor device 11 includes a
substrate 3, an optical semiconductor element 1 mounted on the
substrate 3, a housing 2 formed on the substrate 3, an
encapsulating layer 7 that encapsulates the optical semiconductor
element 1, and a phosphor layer 8 formed on the encapsulating layer
7.
[0242] The substrate 3, the optical semiconductor element 1, the
housing 2, the encapsulating layer 7, and the phosphor layer 8 in
the optical semiconductor device 11 are shaped and disposed in the
same manner as in the first embodiment, and the substrate 3, the
optical semiconductor element 1, the housing 2, and the phosphor
layer 8 are formed from the same materials used in the first
embodiment.
[0243] To obtain the optical semiconductor device 11, first, a
substrate 3 is prepared, and then the optical semiconductor element
1 is mounted on the substrate 3: a housing 2 is formed separately
on the substrate 3.
[0244] Then, the housing 2 is filled with the encapsulating layer
7. To be specific, the housing 2 is filled with the above-described
silicone resin composition, and thereafter, as necessary the
solvent is distilled off, and then the provided silicone resin
composition is heated at the above-described temperature.
[0245] Then, the silicone resin composition is once plasticized (or
liquefied) by the above-described heating and encapsulates the
optical semiconductor element 1, and thereafter cured.
[0246] Thereafter, the phosphor layer 8 is formed on the
encapsulating layer 7.
[0247] The optical semiconductor device 11 is obtained in this
manner.
[0248] The encapsulating layer 7 is composed of the above-described
silicone resin composition, and therefore by being plasticized by
heating at the time of encapsulation and then being cured at low
temperature, the optical semiconductor element 1 can be
encapsulated while effectively preventing damages from impacts or
overheating.
[0249] In the above-described optical semiconductor device 11, the
optical semiconductor element 1 is encapsulated by the
above-described encapsulating layer 7, and therefore has excellent
optical properties and heat resistance, and also has excellent
reliability, mechanical strength, and durability.
[0250] Furthermore, although in the embodiment of FIG. 1, the
encapsulating layer 7 is formed from the silicone resin composition
of the present invention, the housing 2 can also be formed from the
silicone resin composition of the present invention.
[0251] In FIG. 1, the housing 2 as a reflector is formed from a
light reflective composition containing a silicone resin
composition and a light reflective component.
[0252] Examples of light reflective components include those given
as examples of the light reflective component in the first
embodiment, and the mixing ratio is also the same as the mixing
ratio in the first embodiment.
[0253] The light reflective component is homogeneously dispersed
and mixed in the silicone resin composition.
[0254] The light reflective composition is prepared by blending the
above-described silicone resin composition and a light reflective
component, and mixing the mixture homogenously.
[0255] The housing 2 is formed from the above-described light
reflective composition by being molded into the above-described
shape, and then heated. Also, the above-described silicone resin
composition is contained, and therefore the housing 2 has excellent
heat resistance, flexibility, thermoplastic properties, and
thermosetting properties.
[0256] Therefore, the optical semiconductor device 11 including the
above-described housing 2 has excellent optical properties and heat
resistance, while at the same time has excellent flexibility,
mechanical strength and durability.
[0257] Furthermore, in the optical semiconductor device 11 shown in
FIG. 1, the encapsulating layer 7 is formed from the silicone resin
composition, and at the same time, the housing 2 can be formed from
the light reflective composition containing the silicone resin
composition.
[0258] In this embodiment, operational advantages described above
can be achieved.
Third Embodiment
[0259] The silicone resin composition of the present invention
contains a cage octasilsesquioxane, a polysiloxane containing
alkenyl groups at both ends, a hydrosilylation catalyst, a
polysiloxane containing alkenyl groups at side chain.
[0260] Examples of cage octasilsesquioxanes include those cage
octasilsesquioxanes given as examples in the first embodiment.
[0261] When the above-described molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 in formulas (1) and (2) is
more than 6.5/1.5 (=6.5:1.5) (for example, when molar ratio of
monovalent hydrocarbon group:hydrogen in R.sup.2 in formulas (1)
and (2) is 7/1 (=7:1)), the number of moles of the hydrosilyl group
is significantly small, and therefore the reaction degree of the
cage octasilsesquioxane relative to the polysiloxane containing
alkenyl groups at both ends (and polysiloxane containing alkenyl
groups at side chain) is decreased significantly, leading to a low
molecular weight of the obtained silicone resin composition, and a
failure to obtain a solid silicone resin composition.
[0262] On the other hand, when the above-described molar ratio of
monovalent hydrocarbon group:hydrogen in R.sup.2 is below 5.5/2.5
(=5.5:2.5) (for example, when the molar ratio of monovalent
hydrocarbon group:hydrogen in R.sup.2 is 5/3 (=5:3)), the number of
moles of the hydrosilyl group of the cage octasilsesquioxane is
excessively high, and therefore the reaction degree of the cage
octasilsesquioxane relative to the polysiloxane containing alkenyl
groups at both ends (and the polysiloxane containing alkenyl groups
at side chain) is increased excessively, and the silicone resin
composition does not exhibit thermoplastic properties.
[0263] The polysiloxane containing alkenyl groups at both ends is a
straight chain polysiloxane containing alkenyl groups at both ends
of its molecule; to be specific, examples thereof include those
polysiloxanes containing alkenyl groups at both ends given as
examples in the first embodiment and the represented by the
above-described formula (3).
[0264] Examples of hydrosilylation catalysts include those
hydrosilylation catalysts given as examples in the first
embodiment.
[0265] The polysiloxane containing alkenyl groups at side chain is
a polysiloxane containing two or more alkenyl groups at its side
chain. Examples of such polysiloxanes containing alkenyl groups at
side chain include a straight chain siloxane-containing
polysiloxane (straight chain polysiloxane) which contains alkenyl
groups in its side chain bonded to the (silicon atom of) main chain
containing a straight chain siloxane portion (--Si--O--), and/or a
branched siloxane-containing polysiloxane (branched polysiloxane)
which contains alkenyl groups bonded to the silicon atom of the
branched siloxane portion.
[0266] The straight chain siloxane-containing polysiloxane is, to
be specific, represented by formula (8) below:
##STR00034##
(where A to D represent constituent units; A and D represent
terminal units; B and C represent repeating units; R.sup.5
represents a monovalent hydrocarbon group; R.sup.6 represents an
alkenyl group; "b" represents 0 or an integer of 1 or more; and "c"
represents an integer of 2 or more).
[0267] A to D constitute a straight chain siloxane-containing
polysiloxane.
[0268] The monovalent hydrocarbon group represented by R.sup.5 in
formula (8) may be the same or different, and preferably the
same.
[0269] Examples of the monovalent hydrocarbon group represented by
R.sup.5 include the above-described examples of the monovalent
hydrocarbon group represented by R.sup.1 in formulas (1) and (2).
Preferable examples are methyl and phenyl, and a more preferable
example is methyl.
[0270] In view of reactivity and stability, "b" is preferably an
integer of 1 to 10000, more preferably an integer of 1 to 5000.
[0271] In view of reactivity and stability, "c" is preferably an
integer of 2 to 500, more preferably an integer of 2 to 100.
[0272] The number average molecular weight of the straight chain
siloxane-containing polysiloxane is, in view of stability and
handleability, for example, 200 to 1000000, preferably 200 to
80000. The number average molecular weight of the straight chain
siloxane-containing polysiloxane is determined by gel permeation
chromatography (GPC: calibrated with polystyrene standards).
[0273] The alkenyl group content of the straight chain
siloxane-containing polysiloxane is, for example, 0.01 to 10
mmol/g, preferably 0.1 to 5 mmol/g. The alkenyl group content of
the straight chain siloxane-containing polysiloxane is measured
using .sup.1H-NMR based on the area ratio of the alkenyl group to
the methyl group.
[0274] The straight chain siloxane-containing polysiloxane is
synthesized in accordance with, for example, a known method.
Alternatively, a commercially available product (e.g., manufactured
by Gelest, Inc.) can also be used.
[0275] The branched siloxane-containing polysiloxane is, to be
specific, represented by formula (9) below:
##STR00035##
(where E to H represent constituent units; E to G represent
repeating units; H represents a terminal unit; R.sup.7 represents a
monovalent hydrocarbon group; "e" represents an integer of 1 or
more; "f" and "g" represent 0 or an integer of 1 or more; "h"
represents an integer of 4 or more; and at least two R.sup.7 groups
are alkenyl groups per 1 molecule).
[0276] E to H constitute a branched siloxane-containing
polysiloxane.
[0277] The monovalent hydrocarbon group represented by R.sup.7 is,
for example, a saturated hydrocarbon group, an aromatic hydrocarbon
group, or an unsaturated hydrocarbon group (excluding aromatic
hydrocarbon groups).
[0278] Examples of saturated hydrocarbon groups and aromatic
hydrocarbon groups include the above-described examples of the
monovalent hydrocarbon group represented by R.sup.1 in formulas (1)
and (2). Preferable examples are methyl and phenyl, and a more
preferable example is methyl.
[0279] Examples of unsaturated hydrocarbon groups (excluding
aromatic hydrocarbon groups) include the above-described examples
of the alkenyl group represented by R.sup.4 in formula (3), and a
preferable example is vinyl.
[0280] The monovalent hydrocarbon group represented by R.sup.7 in
formula (9) includes at least an alkenyl group, preferably an alkyl
group and an alkenyl group, more preferably a methyl group and a
vinyl group.
[0281] The number of alkenyl groups in the branched
siloxane-containing polysiloxane is 2 or more, preferably 3 or
more, and usually 30 or less.
"e" is preferably an integer of 1 to 100, more preferably an
integer of 1 to 50. "f" is preferably an integer of 1 to 100, more
preferably an integer of 1 to 50. "g" is preferably an integer of 1
to 100, more preferably an integer of 1 to 50. "h" is preferably an
integer of 4 to 100, more preferably an integer of 4 to 30.
[0282] The number average molecular weight of the branched
siloxane-containing polysiloxane is, in view of stability and
handleability, for example, 100 to 10000, preferably 200 to 8000.
The number average molecular weight of the branched
siloxane-containing polysiloxane is determined by gel permeation
chromatography (GPC: calibrated with polystyrene standards).
[0283] The alkenyl group content of the branched
siloxane-containing polysiloxane is, for example, 0.01 to 100
mmol/g, preferably 0.1 to 10 mmol/g. The alkenyl group content of
the branched siloxane-containing polysiloxane is measured using
.sup.1H-NMR based on the area ratio of the alkenyl group to the
methyl group.
[0284] The branched siloxane-containing polysiloxane is synthesized
in accordance with, for example, a known method. Alternatively, a
commercially available product (e.g., manufactured by Gelest, Inc.)
can also be used.
[0285] The silicone resin composition of the present invention is
prepared by blending cage octasilsesquioxane, a polysiloxane
containing alkenyl groups at both ends, a hydrosilylation catalyst,
and a polysiloxane containing alkenyl groups at side chain.
[0286] The mixing ratio of the cage octasilsesquioxane relative to
the silicone resin composition is, for example, 10 to 80 mass %,
preferably 10 to 70 mass %.
[0287] The mixing ratio of the polysiloxane containing alkenyl
groups at both ends is adjusted so that the number of moles of the
alkenyl group of the polysiloxane containing alkenyl groups at both
ends is smaller than the number of moles of the hydrosilyl group of
the cage octasilsesquioxane.
[0288] That is, the molar ratio of the alkenyl group to the
hydrosilyl group (number of moles of the alkenyl group/number of
moles of the hydrosilyl group) is below 1, for example, 0.10 to
0.99, preferably 0.20 to 0.99, more preferably 0.50 to 0.99. In
other words, the mixing ratio of the polysiloxane containing
alkenyl groups at side chain relative to 100 parts by mass of the
total amount of cage octasilsesquioxane and the polysiloxane
containing alkenyl groups at both ends is, for example, 0.001 to 30
parts by mass, preferably 0.01 to 20 parts by mass. The mixing
ratio of the polysiloxane containing alkenyl groups at side chain
relative to 100 parts by mass of the total amount of cage
octasilsesquioxane and polysiloxane containing alkenyl groups at
both ends is, for example, 0.01 to 100 parts by mass, preferably
0.1 to 50 parts by mass.
[0289] When the above-described molar ratio is more than the
above-described range, the hydrosilyl group becomes fewer than the
alkenyl group, and in such a case, after the reaction, surplus
hydrosilyl groups do not remain sufficiently, and thermosetting
properties cannot be imparted to the silicone resin
composition.
[0290] On the other hand, when the above-described molar ratio is
below the above-described range, hydrosilyl groups may remain
excessively, and cage octasilsesquioxanes may be cured by
hydrolysis between each other due to moisture in the air and by
self-condensation, thus, flexibility may not be achieved.
[0291] The mixing ratio of the hydrosilylation catalyst (solid
content) relative to 100 parts by mass of the total amount of cage
octasilsesquioxane and the polysiloxane containing alkenyl groups
at both ends is, for example, 1.0.times.10.sup.-10 to 3 parts by
mass, preferably 1.0.times.10.sup.-8 to 1 part by mass.
[0292] The mixing ratio of the polysiloxane containing alkenyl
groups at side chain is adjusted so that the molar ratio (X/Y) (the
number of moles (X) of the alkenyl group relative to the number of
moles (Y) subtracting the number of moles of the alkenyl group of
the polysiloxane containing alkenyl groups at both ends from the
number of moles of the hydrosilyl group of the cage
octasilsesquioxane) is, for example, 0.001 to 1000, preferably 0.01
to 100.
[0293] To prepare the silicone resin composition, preferably, a
silicone resin precursor obtained by allowing cage
octasilsesquioxane to react with a polysiloxane containing alkenyl
groups at both ends in the presence of a hydrosilylation catalyst;
and a polysiloxane containing alkenyl groups at side chain are
blended.
[0294] That is, first, cage octasilsesquioxane is allowed to react
with the polysiloxane containing alkenyl groups at both ends in the
presence of a hydrosilylation catalyst at a mixing ratio such that
the number of moles of the hydrosilyl group of the cage
octasilsesquioxane is larger than (in excess of) the number of
moles of the alkenyl group of the polysiloxane containing alkenyl
groups at both ends, thereby producing a silicone resin
precursor.
[0295] To obtain the silicone resin precursor, to be more specific,
the above-described cage octasilsesquioxane and the polysiloxane
containing alkenyl groups at both ends are blended at the
above-described mixing ratio along with a hydrosilylation catalyst,
and as necessary, a solvent, and thereafter, as necessary, the
mixture is heated.
[0296] Examples of solvents include aromatic hydrocarbons such as
toluene, aliphatic hydrocarbons such as hexane, and esters such as
ethyl acetate. Preferably, in view of compatibility among
components, aromatic hydrocarbon is used, more preferably toluene
is used.
[0297] The reaction temperature is, for example, 0 to 100.degree.
C., or preferably 20 to 80.degree. C., and the reaction time is,
for example, 0.5 to 96 hours.
[0298] In this manner, cage octasilsesquioxane is allowed to react
with the polysiloxane containing alkenyl groups at both ends. That
is, the hydrosilyl group of the cage octasilsesquioxane and the
alkenyl group of the polysiloxane containing alkenyl groups at both
ends undergo hydrosilylation reaction.
[0299] The degree of hydrosilylation reaction between the
hydrosilyl group of the cage octasilsesquioxane and the alkenyl
group of the polysiloxane containing alkenyl groups at both ends
can be checked by .sup.1H-NMR measurement based on the signal
intensity of the alkenyl group of the polysiloxane containing
alkenyl groups at both ends, and the hydrosilylation reaction is
regarded as terminated when the signal disappeared.
[0300] In the above-described hydrosilylation reaction, cage
octasilsesquioxane is allowed to react with the polysiloxane
containing alkenyl groups at both ends so that the number of moles
of the hydrosilyl group is in excess compared with the number of
moles of the alkenyl group, and after the reaction, the excess
portion of the hydrosilyl group remains.
[0301] The silicone resin precursor is obtained in this manner.
[0302] The silicone resin precursor is liquid or semi-solid.
[0303] Then, the obtained silicone resin precursor and the
polysiloxane containing alkenyl groups at side chain are blended at
the above-described ratio. By heating (described later) thereafter,
the silicone resin precursor is allowed to react with the
polysiloxane containing alkenyl groups at side chain. As necessary,
the solvent was distilled off.
[0304] The silicone resin composition of the present invention can
be obtained in this manner.
[0305] To the silicone resin composition, additives such as the
ones given as examples in the first embodiment can be added at an
appropriate proportion to the extent that does not damage the
excellent effects of the present invention.
[0306] The obtained silicone resin composition is solid. Due to
steric hindrance of the cage octasilsesquioxane, the mobility of
the polysiloxane containing alkenyl groups at both ends is reduced,
and therefore a silicone resin composition in solid state can be
obtained.
[0307] In the silicone resin composition of the present invention,
the molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
is in a specific range, and therefore in the cage
octasilsesquioxane, the proportion of the hydrosilyl group to be
reacted with the alkenyl group of the polysiloxane containing
alkenyl groups at both ends is adjusted. Moreover, the polysiloxane
containing alkenyl groups at both ends is allowed to react with
cage octasilsesquioxane so that the alkenyl group thereof has the
number of moles that is smaller than the number of moles of the
hydrosilyl group of the cage octasilsesquioxane. Therefore, the
obtained silicone resin composition has excellent transparency and
heat resistance, and at the same time, can have both thermoplastic
and thermosetting properties.
[0308] That is, the silicone resin composition is once plasticized
(or liquefied) by the above-described heating, and thereafter,
cured by heat.
[0309] Thermoplastic properties of the silicone resin composition
are exhibited when cage octasilsesquioxane and the polysiloxane
containing alkenyl groups at both ends are heated, which causes
increase in their mobility.
[0310] The thermoplastic temperature of the silicone resin
composition is, for example, 40 to 150.degree. C., preferably 50 to
100.degree. C. The thermoplastic temperature is a temperature at
which the silicone resin composition exhibits thermoplastic
properties, to be specific, a temperature at which a solid silicone
resin composition is softened by heating and becomes liquid
completely, and is substantially the same as the softening
temperature.
[0311] The once plasticized silicone resin composition exhibits
thermosetting properties, to be specific, by reaction between the
hydrosilyl group remaining in the silicone resin precursor and the
alkenyl group of the polysiloxane containing alkenyl groups at side
chain.
[0312] To be more specific, the hydrosilyl group of the cage
octasilsesquioxane in the silicone resin precursor and the alkenyl
group of the polysiloxane containing alkenyl groups at side chain
undergo hydrosilylation reaction.
[0313] The thermosetting temperature of the silicone resin
composition is relatively low, for example, 100 to 250.degree. C.,
preferably 120 to 250.degree. C. The thermosetting temperature is a
temperature at which the silicone resin composition exhibits
thermosetting properties, to be specific, a temperature at which
the plasticized silicone resin composition is cured by heating and
becomes solid completely.
[0314] In the silicone resin composition, the alkenyl group of the
polysiloxane containing alkenyl groups at side chain is allowed to
react with the residual hydrosilyl group in the cage
octasilsesquioxane, and such reaction allows crosslinking to the
cage octasilsesquioxane. Therefore, improvement in flexibility of
the silicone resin composition can be achieved.
[0315] Furthermore, the silicone resin composition achieves a
decreased thermosetting temperature (e.g., 100 to 250.degree.
C.).
[0316] In the above-described embodiment, first, the silicone resin
precursor is obtained, and thereafter, the silicone resin precursor
and polysiloxane containing alkenyl groups at side chain are
blended, thereby preparing a silicone resin composition, but the
preparation method of the silicone resin composition is not limited
thereto. The silicone resin composition can also be prepared by,
for example, by blending at once cage octasilsesquioxane, a
polysiloxane containing alkenyl groups at both ends, a
hydrosilylation catalyst, and a polysiloxane containing alkenyl
groups at side chain, and as necessary, heating the mixture.
[0317] The silicone resin composition can be used, without
limitation, for example, as an encapsulating material and a filler
material for various industrial products. The silicone resin
composition can be formed, preferably, as an encapsulating layer
for various industrial products, to be specific, as an
encapsulating layer for encapsulating an optical semiconductor
element.
[0318] The optical semiconductor element is not particularly
limited, as long as the optical semiconductor element is an element
provided in an optical semiconductor device, and examples thereof
include a light-emitting diode (LED), a photodiode, a
phototransistor, and a laser diode. A preferable example is an LED,
a more preferable example is an LED for lighting.
[0319] Next, an embodiment of the optical semiconductor device of
the present invention is described with reference to FIG. 1.
[0320] In FIG. 1, an optical semiconductor device 11 includes a
substrate 3, an optical semiconductor element 1 mounted on the
substrate 3, a housing 2 formed on the substrate 3, an
encapsulating layer 7 that encapsulates the optical semiconductor
element 1, and a phosphor layer 8 formed on the encapsulating layer
7.
[0321] The substrate 3, the optical semiconductor element 1, the
housing 2, the encapsulating layer 7, and the phosphor layer 8 in
the optical semiconductor device 11 are shaped and disposed in the
same manner as in the first embodiment, and the substrate 3, the
optical semiconductor element 1, the housing 2, and the phosphor
layer 8 are formed from the same materials used in the first
embodiment.
[0322] To obtain the optical semiconductor device 11, first, a
substrate 3 is prepared, and then the optical semiconductor element
1 is mounted on the substrate 3: a housing 2 is formed separately
on the substrate 3.
[0323] Then, the housing 2 is filled with the encapsulating layer
7. To be specific, the housing 2 is filled with the above-described
silicone resin composition, and thereafter, as necessary the
solvent is distilled off, and then the provided silicone resin
composition is heated at the above-described temperature.
[0324] Then, the silicone resin composition is once plasticized (or
liquefied) by the above-described heating and encapsulates the
optical semiconductor element 1, and thereafter cured.
[0325] Thereafter, the phosphor layer 8 is formed on the
encapsulating layer 7.
[0326] The optical semiconductor device 11 is obtained in this
manner.
[0327] The encapsulating layer 7 is composed of the above-described
silicone resin composition, and therefore by being plasticized by
heating at the time of encapsulation and then being cured at low
temperature, the optical semiconductor element 1 can be
encapsulated while effectively preventing damages from impacts or
overheating.
[0328] In the above-described optical semiconductor device 11, the
optical semiconductor element 1 is encapsulated by the
above-described encapsulating layer 7, and therefore has excellent
optical properties and heat resistance, and also has excellent
reliability, mechanical strength, and durability.
[0329] Furthermore, although in the embodiment of FIG. 1, the
encapsulating layer 7 is formed from the silicone resin composition
of the present invention, the housing 2 can also be formed from the
silicone resin composition of the present invention.
[0330] In FIG. 1, the housing 2 as a reflector is formed from a
light reflective composition containing a silicone resin
composition and a light reflective component.
[0331] Examples of light reflective components include those given
as examples of the light reflective component in the first
embodiment, and the mixing ratio is also the same as the mixing
ratio in the first embodiment.
[0332] The light reflective component is homogeneously dispersed
and mixed in the silicone resin composition.
[0333] The light reflective composition is prepared by blending the
above-described silicone resin composition and a light reflective
component, and mixing the mixture homogenously.
[0334] The housing 2 is formed from the above-described light
reflective composition by being molded into the above-described
shape, and then heated. Also, the above-described silicone resin
composition is contained, and therefore the housing 2 has excellent
heat resistance, flexibility, thermoplastic properties, and
thermosetting properties.
[0335] Therefore, the optical semiconductor device 11 including the
above-described housing 2 has excellent optical properties and heat
resistance, while at the same time has excellent flexibility,
mechanical strength, and durability.
[0336] Furthermore, in the optical semiconductor device 11 shown in
FIG. 1, the encapsulating layer 7 is formed from the silicone resin
composition, and at the same time, the housing 2 can also be formed
from the light reflective composition containing the silicone resin
composition.
[0337] In this embodiment, operational advantages described above
can be achieved.
EXAMPLES
[0338] While the present invention is described in further detail
with reference to Synthesis Examples, Comparative Synthesis
Examples, Examples, and Comparative Examples in the following, the
present invention is not limited to any of them by no means.
Synthesis Example 1
Synthesis of Cage Octasilsesquioxane
[0339] 35.8 mL (160.6 mol) of tetraethoxysilane was gradually added
dropwise to a liquid mixture of 66.8 mL (158.6 mol) of tetramethyl
ammonium hydroxide (25% methanol solution), 32.8 mL of methanol,
and 24.6 mL of distilled water. The mixture was stirred for a whole
day, thereby allowing the mixture to react.
[0340] Then, the reaction liquid was filtered, and the filtrate was
added dropwise to a liquid mixture of 428 mL of hexane, 7.1 g (75
mmol) of dimethylchlorosilane, and 24.4 g (225 mmol) of
trimethylchlorosilane, and the mixture was stirred for a whole day.
Thereafter, the reactant was extracted with hexane; and magnesium
sulfate was added to the extract and dried. Thereafter, hexane was
removed once, and then hexane was further added for
recrystallization, thereby producing a white solid cage
octasilsesquioxane.
[0341] It was confirmed that, by using .sup.1H-NMR, the obtained
cage octasilsesquioxane had the structure of formula (2); and that
R.sup.1 was a methyl group and R.sup.2 was hydrogen and a methyl
group in formula (2). The molar ratio of methyl group to hydrogen
in R.sup.2 (average value of cage octasilsesquioxane as a whole)
was calculated and determined to be methyl group:hydrogen=6:2.
Synthesis Example 2 and Comparative Synthesis Examples 1 and 2
[0342] Cage octasilsesquioxanes of Synthesis Example 2, and
Comparative Synthesis Examples 1 and 2 were obtained in the same
manner as in Synthesis Example 1, except that the mixing ratios of
dimethylchlorosilane and trimethylchlorosilane were changed in
accordance with Table 1.
[0343] It was confirmed that, by using .sup.1H-NMR, the obtained
cage octasilsesquioxane had the structure of formula (2), and
groups of R.sup.1 and R.sup.2 in formula (2) were identified. The
molar ratio of methyl group to hydrogen in R.sup.2 (average value
of cage octasilsesquioxane as a whole) was calculated. The results
are shown in Table 1.
TABLE-US-00001 TABLE 1 Synthesis Example .cndot. Comparative
Synthesis Example Comparative Comparative Synthesis Synthesis
Synthesis Synthesis Example 1 Example 2 Example 1 Example 2
Tetraethoxysilane Blending (g) 35.8 35.8 35.8 35.8 Amount (mmol)
160.6 160.6 160.6 160.6 Dimethylchlorosilane Blending (g) 7.1 8.9
3.5 10.6 Amount (mmol) 75 93.8 37.5 112.5 Trimethylchlorosilane
Blending (g) 24.4 22.4 28.5 20.4 Amount (mmol) 225 206.5 262.5
187.5 Formulas (1) and (2) R.sup.1 Methyl Methyl Methyl Methyl
Group Group Group Group R.sup.2 Methyl Group:Hydrogen 6:2 5.5:2.5
7:1 5:3 (Molar Ratio)
1 Examples and Comparative Examples corresponding to the First
Invention Group
Examples 1 to 4 and Comparative Examples 1 to 5
Example 1
[0344] 0.36 g of cage octasilsesquioxane (in formula (2), R.sup.2
ratio=methyl group:hydrogen (molar ratio)=6:2) of Synthesis Example
1, 0.24 g of an alkenyl group-containing polysiloxane (in formula
(3), R.sup.3 is methyl group, R.sup.4 is vinyl group, "a" was 8,
number average molecular weight 800, manufactured by Gelest, Inc.),
1 g of toluene, and 0.5 .mu.L of a solution of
platinum-divinylsiloxane complex (hydrosilylation catalyst, toluene
solution, platinum concentration 2 mass %) were blended, and the
mixture was stirred at 50.degree. C. for 15 hours. The silicone
resin precursor was obtained in this manner. The molar ratio
(=vinyl group/hydrosilyl group) of the vinyl group of the alkenyl
group-containing polysiloxane to the hydrosilyl group of the cage
octasilsesquioxane was 0.91.
[0345] Thereafter, to the obtained silicone resin precursor, 0.06 g
of a hydroxyl group-containing polysiloxane (in formula (4),
R.sup.5 was methyl group, "b" was 38, number average molecular
weight 3000, manufactured by Gelest, Inc.) was blended, and the
mixture was stirred. The ratio of the hydroxyl group of the
hydroxyl group-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.67.
[0346] Thereafter, toluene was distilled off, thereby producing a
transparent solid silicone resin composition.
Example 2
[0347] A silicone resin precursor was obtained in the same manner
as in Example 1, except that instead of 0.06 g of hydroxyl
group-containing polysiloxane (in formula (3), R.sup.5 was methyl
group, "b" was 38, number average molecular weight 3000,
manufactured by Gelest, Inc.), 0.06 g of hydroxyl group-containing
polysiloxane (in formula (3), R.sup.5 was methyl group, "b" was
1615, number average molecular weight 12000, manufactured by
Gelest, Inc.) was blended, and then a transparent solid silicone
resin composition was obtained.
[0348] The ratio of the hydroxyl group of the hydroxyl
group-containing polysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio,
0.67.
Example 3
[0349] A silicone resin precursor was obtained in the same manner
as in Example 1, except that instead of 0.36 g of the cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.29 g of
cage octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=5.5:2.5) of Synthesis Example 2 was
blended, and then a transparent solid silicone resin composition
was obtained.
[0350] The ratio of the hydroxyl group of the hydroxyl
group-containing polysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio,
0.67.
Example 4
[0351] A silicone resin precursor was obtained in the same manner
as in Example 1, except that instead of 0.24 g of alkenyl
group-containing polysiloxane (in formula (3), R.sup.3 was methyl
group, R.sup.4 was vinyl group, "a" was 8, number average molecular
weight 800, manufactured by Gelest, Inc.), 0.6 g of alkenyl
group-containing polysiloxane (in formula (3), R.sup.3 was methyl
group, R.sup.4 was vinyl group, "a" was 25, number average
molecular weight 2000, manufactured by Gelest, Inc.) was blended,
and then a transparent solid silicone resin composition was
obtained.
[0352] The ratio of the hydroxyl group of the hydroxyl
group-containing polysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio,
0.67.
Comparative Example 1
[0353] A silicone resin precursor was obtained in the same manner
as in Example 1, except that instead of 0.24 g of alkenyl
group-containing polysiloxane (in formula (3), R.sup.3 was methyl
group, R.sup.4 was vinyl group, "a" was 8, number average molecular
weight 800, manufactured by Gelest, Inc.), 0.24 g of polysiloxane
(in formula (3), both of R.sup.3 and R.sup.4 were methyl groups,
"a" was 25, number average molecular weight 800, manufactured by
Gelest, Inc.) containing no alkenyl group was blended, and then a
cloudy oil silicone resin composition was obtained.
Comparative Example 2
[0354] A silicone resin precursor was obtained in the same manner
as in Example 1, except that instead of 0.36 g of cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.72 g of
cage octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=7:1) of Comparative Synthesis Example
1 was blended, and then a transparent oil silicone resin
composition was obtained. The ratio of the hydroxyl group of the
hydroxyl group-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.67.
Comparative Example 3
[0355] A silicone resin precursor was obtained in the same manner
as in Example 1, except that instead of 0.36 g of cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.24 g of
cage octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=5:3) of Comparative Synthesis Example
2 was blended, and then a transparent solid (gel) silicone resin
composition was obtained. The ratio of the hydroxyl group of the
hydroxyl group-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.67.
Comparative Example 4
[0356] The same operation as in Example 1 was performed, except
that a solution of platinum-divinylsiloxane complex
(hydrosilylation catalyst, toluene solution, platinum concentration
2 mass %) was not blended; and a silicone resin composition was
obtained without obtaining a silicone resin precursor. That is, to
the cage octasilsesquioxane and alkenyl group-containing
polysiloxane, a hydroxyl group-containing polysiloxane was blended,
and a cloudy oil silicone resin composition was obtained.
Comparative Example 5
[0357] A silicone resin precursor was obtained in the same manner
as in Example 1, except that the hydroxyl group-containing
polysiloxane (in formula (4), R.sup.5 was methyl group, "b" was 38,
number average molecular weight 3000, manufactured by Gelest, Inc.)
was not blended, and this was regarded as a silicone resin
composition. The silicone resin composition was in cloudy oil
state.
Evaluation
1. Thermoplastic and Thermosetting Properties
[0358] Behaviors when heated of the silicone resin compositions of
Examples 1 to 4 and Comparative Examples 1 to 5 were evaluated.
[0359] To be specific, samples having a size of 1 cm square were
made from the silicone resin compositions of Examples 1 to 4, and
Comparative Examples 3 and 5. The samples were placed on a hot
plate and heated to 30 to 200.degree. C., and their thermoplastic
temperature and thermosetting temperature were measured with visual
observation. The results are shown in Table 2.
[0360] The sample of Comparative Example 3 was solid, but did not
soften by heat, and therefore its thermoplastic temperature could
not be evaluated. The sample of Comparative Example 3 was solid,
and therefore its thermosetting temperature could not be
evaluated.
[0361] On the other hand, the samples of Comparative Examples 1, 2,
and 4 were liquid, and therefore their thermoplastic temperatures
could not be evaluated. Also, a predetermined amount (about 1 mL)
of the samples of Comparative Examples 1, 2 and 4 were applied on a
hot plate, and heated to 30 to 200.degree. C. The samples were
observed, but because the samples were not cured by heating, their
thermosetting temperatures could not be evaluated.
2. Heat Resistance (Reduction Rate of Light Transmittance)
[0362] Transmittance of light at a wavelength of 450 nm of samples
made as described above of Examples 1 to 4 was measured by a
spectrophotometer (U4100, manufactured by Hitachi High-Technologies
Corporation).
[0363] Thereafter, the samples were placed in a hot air dryer of
200.degree. C. for a predetermined period. Then, after elapses of
24 hours and 168 hours, the samples were taken out from the hot air
dryer, and transmittance of the taken samples of light at a
wavelength of 450 nm was measured.
[0364] Then, the reduction rates (=(light transmittance after
placement in the dryer/light transmittance before placement in the
dryer).times.100) of the light transmittance of the samples were
calculated. The results are shown in Table 2.
3. Flexibility (Tensile Modulus and Elongation Percentage)
[0365] Samples having a thickness of 600 .mu.m were made, and then
placed in a hot air dryer of 200.degree. C. The samples were taken
out after an elapse of 24 hours, and their tensile modulus at
25.degree. C., and elongation percentage at 25.degree. C. were
measured using a universal testing machine (autograph, manufactured
by Shimadzu Corporation). The results are shown in Table 2.
TABLE-US-00002 TABLE 2 Example .cndot. Comparative Example
Comparative Comparative Comparative Comparative Comparative Example
1 Example 2 Example 3 Example 4 Example 1 Example 2 Example 3
Example 4 Example 5 Cage Synthesis Example .cndot. Comparative
Synthesis Synthesis Synthesis Synthesis Synthesis Comparative
Comparative Synthesis Synthesis Octasilsesquioxane Synthesis
Example Example 1 Example 1 Example 2 Example 1 Example 1 Synthesis
Synthesis Example 1 Example 1 Example 1 Example 2 R.sup.2/Methyl
Group:Hydrogen 6:2 6:2 5.5:2.5 6:2 6:2 7:1 5:3 6:2 6:2 (Molar
Ratio) Blending Amount (g) 0.36 0.36 0.29 0.36 0.36 0.72 0.24 0.36
0.36 Alkenyl R.sup.3 Methyl Group Methyl Group Methyl Group Methyl
Group Methyl Group Methyl Group Methyl Group Methyl Group Methyl
Group group- R.sup.4 Vinyl Group Vinyl Group Vinyl Group Vinyl
Group Methyl Group Vinyl Group Vinyl Group Vinyl Group Vinyl Group
containing Number average molecular weight 800 800 800 2000 800 800
800 800 800 polysiloxane Blending Amount (g) 0.24 0.24 0.24 0.6
0.24 0.24 0.24 0.24 0.24 Vinyl Group/Hydrosilyl Group (Molar Ratio)
0.91 0.91 0.91 0.91 -- 0.90 0.91 0.91 0.91 Hydrosilylation Catalyst
Solution of Solution of Solution of Solution of Solution of
Solution of Solution of -- Solution of Platinum- Platinum-
Platinum- Platinum- Platinum- Platinum- Platinum- Platinum-
Divinylsiloxane Divinylsiloxane Divinylsiloxane Divinylsiloxane
Divinylsiloxane Divinylsiloxane Divinylsiloxane Divinylsiloxane
Complex Complex Complex Complex Complex Complex Complex Complex
Hydroxyl Group- R.sup.5 Methyl Group Methyl Group Methyl Group
Methyl Group Methyl Group Methyl Group Methyl Group Methyl Group --
containing Number average molecular weight 3000 12000 3000 3000
3000 3000 3000 3000 -- Polysiloxane Blending Amount (g) 0.06 0.06
0.06 0.06 0.06 0.06 0.06 0.06 -- Ratio (X/Y)[Molar Ratio] of
Hydroxyl Group 0.67 0.67 0.67 0.67 0.12 0.67 0.67 -- -- Relative to
residual hydrosilyl group Evaluation on State at Room Temperature
Transparent Transparent Transparent Transparent Cloudy Oil
Transparent Oil Transparent Cloudy Oil Transparent Silicone Resin
Solid Solid Solid Solid Solid Solid Composition Thermoplastic
Temperature (.degree. C.) 65 60 70 60 --*.sup.1 --*.sup.1 --*.sup.2
--*.sup.1 70 Thermosetting Temperature (.degree. C.) 180 180 180
180 --*.sup.3 --*.sup.3 -- --*.sup.3 200 Heat Reduction Rate 24 h
99 99 99 99 -- -- -- -- 99 Resistance (%) of Light 168 h 98 99 98
98 -- -- -- -- 98 Transmittance Flexibility Tensile Modulus (MPa)
0.02 0.01 0.03 0.01 -- -- -- -- 0.06 Elongation Percentage (%) 150
160 120 130 -- -- -- -- 110 *.sup.1Not Evaluated Because of Oil
State *.sup.2Not Plasticized *.sup.3Not Cured
[0366] As is clear from Table 2, the silicone resin compositions of
Examples 1 to 4 and Comparative Example 5 have both thermoplastic
and thermosetting properties. Moreover, the silicone resin
compositions of Examples 1 to 4 have a low thermosetting
temperature, i.e., 180.degree. C., and have excellent
elongation.
[0367] On the other hand, the silicone resin compositions of
Comparative Examples 1 to 4 do not have both thermoplastic and
thermosetting properties.
[0368] To be specific, the silicone resin composition of
Comparative Example 1 does not contain an alkenyl group-containing
polysiloxane, and therefore hydrosilylation reaction did not occur,
and the obtained silicone resin composition did not become solid at
room temperature, but became liquid at room temperature. That is,
the silicone resin composition of Comparative Example 1 does not
have thermoplastic properties.
[0369] In the silicone resin composition of Comparative Example 2,
a molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
in the cage octasilsesquioxane as a whole, as an average value, was
7:1, and the number of moles of the hydrosilyl group was small, and
therefore the reaction degree of cage octasilsesquioxane and the
alkenyl group-containing polysiloxane was reduced, causing a low
molecular weight of the silicone resin composition, and the
obtained silicone resin composition did not become solid at room
temperature, but became liquid at room temperature. That is, the
silicone resin composition of Comparative Example 2 did not have
thermoplastic properties.
[0370] In the silicone resin composition of Comparative Example 3,
the molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
in the cage octasilsesquioxane as a whole, as an average value, was
5:3, and the number of moles of the hydrosilyl group of the cage
octasilsesquioxane was large, and the obtained silicone resin
composition did not exhibit thermoplastic properties.
[0371] In the silicone resin composition of Comparative Example 4,
the hydrosilylation catalyst was not blended, and therefore
hydrosilylation reaction did not occur, and the silicone resin
precursor could not be obtained. Moreover, the silicone resin
composition did not become solid at room temperature, but became
liquid at room temperature. That is, the silicone resin composition
of Comparative Example 4 did not have thermoplastic properties.
[0372] The silicone resin composition of Comparative Example 5 had
both thermoplastic and thermosetting properties, but compared with
the silicone resin compositions of Examples 1 to 4, the
thermosetting temperature was high, i.e., 200.degree. C., and had a
high modulus of elasticity and a low elongation percentage.
[0373] This is probably because the hydroxyl group-containing
polysiloxane was not blended therein, and therefore cage
octasilsesquioxane were cured by hydrolysis between each other due
to moisture in the air and self-condensation, which caused a short
crosslinking distance.
2 Examples and Comparative Examples Corresponding to the Second
Invention Group
Examples 5 to 10 and Comparative Examples 6 to 10
Example 5
[0374] 0.36 g of cage octasilsesquioxane (in formula (2), R.sup.2
ratio=methyl group:hydrogen (molar ratio)=6:2) of Synthesis Example
1, 0.24 g of an alkenyl group-containing polysiloxane (in formula
(3), R.sup.3 was methyl group, R.sup.4 was vinyl group, "a" was 8,
number average molecular weight 800), 1 g of toluene, and 0.1 .mu.L
of a solution of platinum-divinylsiloxane complex (hydrosilylation
catalyst, toluene solution, platinum concentration 2 mass %) were
blended, and the mixture was stirred at 50.degree. C. for 15 hours.
The silicone resin precursor was obtained in this manner. The molar
ratio (=vinyl group/hydrosilyl group) of the vinyl group of the
alkenyl group-containing polysiloxane to the hydrosilyl group of
the cage octasilsesquioxane was 0.91.
[0375] Thereafter, to the obtained silicone resin precursor, 0.03 g
(5 parts by mass relative to 100 parts by mass of silicone resin
precursor) of a side-chain type organohydrogenpolysiloxane (in
formula (5), R.sup.5 was methyl group, b=510, c=200; number average
molecular weight 50000, SiH group-containing amount 4 mmol/g) was
blended, and the mixture was stirred.
[0376] The ratio (X/Y) of the hydrosilyl group in the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 4.
[0377] Thereafter, toluene was distilled off, thereby producing a
cloudy solid silicone resin composition. The side-chain type
organohydrogenpolysiloxane content in the silicone resin
composition was 4.7 mass %.
Example 6
[0378] A silicone resin precursor was obtained in the same manner
as in Example 5, except that the blending amount of the side-chain
type organohydrogenpolysiloxane (in formula (5), R.sup.5 was methyl
group, b=510, c=200; number average molecular weight 50000, SiH
group-content 4 mmol/g) was changed from 0.03 g to 0.14 g (23.3
parts by mass relative to 100 parts by mass of silicone resin
precursor), and then a cloudy solid silicone resin composition was
obtained.
[0379] The ratio (X/Y) of the hydrosilyl group of the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 18.7,
and the side-chain type organohydrogenpolysiloxane content in the
silicone resin composition was 18.8 mass %.
Example 7
[0380] A silicone resin precursor was obtained in the same manner
as in Example 5, except that instead of 0.03 g of the side-chain
type organohydrogenpolysiloxane (in formula (5), R.sup.5 was methyl
group, b=510, c=200; number average molecular weight 50000, SiH
group-content 4 mmol/g), 0.03 g (5 parts by mass relative to 100
parts by mass of the silicone resin precursor) of a side-chain type
organohydrogenpolysiloxane (in formula (5), R.sup.5 was methyl
group, b=510, c=200; number average molecular weight 1000, SiH
group-content 7 mmol/g) was blended; and then a cloudy solid
silicone resin composition was obtained.
[0381] The ratio (X/Y) of the hydrosilyl group of the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 7, and
the side-chain type organohydrogenpolysiloxane content in the
silicone resin composition was 4.7 mass %.
Example 8
[0382] A silicone resin precursor was obtained in the same manner
as in Example 5, except that instead of 0.03 g of the side-chain
type organohydrogenpolysiloxane (in formula (5), R.sup.5 was methyl
group, b=510, c=200; number average molecular weight 50000, SiH
group-content 4 mmol/g), 0.03 g (5 parts by mass relative to 100
parts by mass of silicone resin precursor) of both-ends type
organohydrogenpolysiloxane (non-side chain
hydrogen/hydrogen-terminated (both ends) organopolysiloxane, in
formula (7), R.sup.6 was methyl group, d=4; number average
molecular weight 450, SiH group-content 4.4 mmol/g) was blended;
and then a cloudy solid silicone resin composition was
obtained.
[0383] The ratio (X/Y) of the hydrosilyl group of the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 4.4,
and the both-ends type organohydrogenpolysiloxane content in the
silicone resin composition was 4.7 mass %.
Example 9
[0384] A silicone resin precursor was obtained in the same manner
as in Example 5, except that instead of 0.36 g of the cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.29 g of
the cage octasilsesquioxane (methyl group:hydrogen (molar
ratio)=5.5:2.5) of Synthesis Example 2 was blended; and then a
cloudy solid silicone resin composition was obtained.
[0385] The ratio (X/Y) of the hydrosilyl group of the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 4, and
the side-chain type organohydrogenpolysiloxane content in the
silicone resin composition was 5.4 mass %.
Example 10
[0386] A silicone resin precursor was obtained in the same manner
as in Example 5, except that instead of 0.24 g of the alkenyl
group-containing polysiloxane (in formula (3), R.sup.3 was methyl
group, R.sup.4 was vinyl group, a=8; number average molecular
weight 800), 0.6 g of the alkenyl group-containing polysiloxane (in
formula (3), R.sup.3 was methyl group, R.sup.4 was vinyl group,
a=25; number average molecular weight 2000) was blended, and then a
cloudy solid silicone resin composition was obtained.
[0387] The ratio (X/Y) of the hydrosilyl group of the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 4, and
the side-chain type organohydrogenpolysiloxane content in the
silicone resin composition was 3.0 mass %.
Comparative Example 6
[0388] A silicone resin precursor was obtained in the same manner
as in Example 5, except that instead of 0.24 g of the alkenyl
group-containing polysiloxane (in formula (3), R.sup.3 was methyl
group, R.sup.4 was vinyl group, a=8; number average molecular
weight 800), 0.24 g of a polysiloxane (in formula (3), R.sup.3 and
R.sup.4 were both methyl groups, a=8; number average molecular
weight 800) that does not contain an alkenyl group was blended, and
then a cloudy oil silicone resin composition was obtained.
Comparative Example 7
[0389] A silicone resin precursor was obtained in the same manner
as in Example 5, except that instead of 0.36 g of the cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.72 g of
the cage octasilsesquioxane (methyl group:hydrogen (molar
ratio)=7:1) of Comparative Synthesis Example 1 was blended, and
then a cloudy oil silicone resin composition was obtained.
[0390] The ratio (X/Y) of the hydrosilyl group of the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 4. The
side-chain type organohydrogenpolysiloxane content in the silicone
resin composition was 3.0 mass %.
Comparative Example 8
[0391] A silicone resin precursor was obtained in the same manner
as in Example 5, except that instead of 0.36 g of the cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.24 g of
the cage octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=5:3) of Comparative Synthesis Example
2 was blended; and then a transparent solid (gel) silicone resin
composition was obtained.
[0392] The ratio (X/Y) of the hydrosilyl group of the
organohydrogenpolysiloxane relative to the residual hydrosilyl
group in the silicone resin precursor was, in a molar ratio, 4. The
side-chain type organohydrogenpolysiloxane content in the silicone
resin composition was 5.9 mass %.
Comparative Example 9
[0393] The same operation as in Example 5 was performed, except
that a solution of platinum-divinylsiloxane complex
(hydrosilylation catalyst, toluene solution, platinum concentration
2 mass %) was not blended. A silicone resin composition was
obtained without obtaining the silicone resin precursor. That is,
organohydrogenpolysiloxane was blended to cage octasilsesquioxane
and the alkenyl group-containing polysiloxane, thereby producing a
cloudy oil silicone resin composition.
Comparative Example 10
[0394] A silicone resin precursor was obtained in the same manner
as in Example 5, except that organohydrogenpolysiloxane (in formula
(5), R.sup.5 was methyl group, b=510, c=200; number average
molecular weight 50000, SiH group-content 4 mmol/g) was not
blended, and the silicone resin precursor was obtained as a
silicone resin composition. The silicone resin composition was
cloudy solid state.
Evaluation
1. Thermoplastic and Thermosetting Properties
[0395] Behaviors when heated of the silicone resin compositions of
Examples 5 to 10 and Comparative Examples 6 to 10 were
evaluated.
[0396] To be specific, samples having a size of 1 cm square were
made from the silicone resin compositions of Examples 5 to 10 and
Comparative Examples 8 and 10. The samples were placed on a hot
plate and heated to 30 to 200.degree. C., and their thermoplastic
temperature and thermosetting temperature were measured with visual
observation. The results are shown in Table 3.
[0397] The sample of Comparative Example 8 was solid, but did not
soften by heat, and therefore its thermoplastic temperature could
not be evaluated. Also, the sample of Comparative Example 8 was
solid, and therefore its thermosetting temperature could not be
evaluated.
[0398] On the other hand, the samples of Comparative Examples 6, 7,
and 9 were liquid, and therefore their thermoplastic temperatures
could not be evaluated. Also, a predetermined amount (about 1 mL)
of the samples of Comparative Examples 6, 7, and 9 were applied on
a hot plate, and heated to 30 to 200.degree. C. The samples were
observed, but because the samples were not cured by heating, their
thermosetting temperatures could not be evaluated.
2. Heat Resistance (Reduction Rate of Light Transmittance)
[0399] Transmittance of light at a wavelength of 450 nm of the
samples made as described above of Examples 5 to 10 and Comparative
Example 10 was measured by a spectrophotometer (U4100, manufactured
by Hitachi High-Technologies Corporation).
[0400] Thereafter, the samples were placed in a hot air dryer of
200.degree. C. for a predetermined period. Then, after elapses of
24 hours and 168 hours, the samples were taken out from the hot air
dryer, and transmittance of the taken samples of light at a
wavelength of 450 nm was measured.
[0401] Then, the reduction rates (=(light transmittance after
placement in the dryer/light transmittance before placement in the
dryer).times.100) of the light transmittance of the samples were
calculated. The results are shown in Table 3.
3. Flexibility (Tensile Modulus and Elongation Percentage)
[0402] The tensile modulus and elongation percentage of the
silicone resin compositions of Examples 5 to 10 and Comparative
Example 10 were evaluated.
[0403] To be specific, samples having a thickness of 600 .mu.m were
made from the silicone resin compositions of Examples 5 to 10 and
Comparative Example 10, and then placed in a hot air dryer of
200.degree. C. The samples were taken out after an elapse of 24
hours, and their tensile modulus at 25.degree. C., and elongation
percentage at 25.degree. C. were measured using a universal testing
machine (autograph, manufactured by Shimadzu Corporation). The
results are shown in Table 3.
TABLE-US-00003 TABLE 3 Example .cndot. Comparative Example
Comparative Comparative Comparative Comparative Comparative Example
5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 6
Example 7 Example 8 Example 9 Example 10 Cage Synthesis Example
.cndot. Comparative Synthesis Synthesis Synthesis Synthesis
Synthesis Synthesis Synthesis Comparative Comparative Synthesis
Synthesis octasilsesquioxane Synthesis Example Example 1 Example 1
Example 1 Example 1 Example 2 Example 1 Example 1 Synthesis
Synthesis Example 1 Example 1 Example 1 Example 2 R.sup.2/Methyl
Group:Hydrogen (Molar 6:2 6:2 6:2 6:2 5.5:2.5 6:2 6:2 7:1 5:3 6:2
6:2 Ratio) Blending Amount (g) 0.36 0.36 0.36 0.36 0.29 0.36 0.36
0.72 0.24 0.36 0.36 Alkenyl R.sup.3 Methyl Methyl Methyl Methyl
Methyl Methyl Methyl Methyl Methyl Methyl Methyl group- Group Group
Group Group Group Group Group Group Group Group Group containing
R.sup.4 Vinyl Group Vinyl Group Vinyl Group Vinyl Group Vinyl Group
Vinyl Group Methyl Vinyl Group Vinyl Group Vinyl Group Vinyl Group
polysiloxane Group Number average molecular weight 800 800 800 800
800 2000 800 800 800 800 800 Blending Amount (g) 0.24 0.24 0.24
0.24 0.24 0.6 0.24 0.24 0.24 0.24 0.24 Vinyl Group/Hydrosilyl Group
(Molar Ratio) 0.91 0.91 0.91 0.91 0.91 0.91 -- 0.90 0.91 0.91 0.91
Hydrosilylation Catalyst Solution of Solution of Solution of
Solution of Solution of Solution of Solution of Solution of
Solution of -- Solution of Platinum- Platinum- Platinum- Platinum-
Platinum- Platinum- Platinum- Platinum- Platinum- Platinum-
Divinyl- Divinyl- Divinyl- Divinyl- Divinyl- Divinyl- Divinyl-
Divinyl- Divinyl- Divinyl- siloxane siloxane siloxane siloxane
siloxane siloxane siloxane siloxane siloxane siloxane Complex
Complex Complex Complex Complex Complex Complex Complex Complex
Complex Organohydro- Side-Chain Type R.sup.5 Methyl Methyl Methyl
-- Methyl Methyl Methyl Methyl Methyl Methyl -- genpolysiloxane
Group Group Group Group Group Group Group Group Group Number
average 50000 50000 1000 -- 50000 50000 50000 50000 50000 50000
molecular weight Both-Ends Type R.sup.6 -- -- -- Methyl -- -- -- --
-- -- Group Number average -- -- -- 450 -- -- -- -- -- -- molecular
weight Blending Amount(g) 0.03 0.14 0.03 0.03 0.03 0.03 0.03 0.03
0.03 0.03 Ratio of 4.7 18.8 4.7 4.7 5.4 3.0 4.7 3.0 5.9 4.7
Organohydrogenpolysiloxane relative to Silicone Resin Composition
(mass %) Ratio of Hydrosilyl Group(X/Y)*.sup.4 4 18.7 7 4.4 4 4
0.36 4 4 -- Evaluation on State at Room Temperature Transparent
Transparent Transparent Transparent Transparent Transparent Cloudy
Oil Transparent Transparent Cloudy Oil Transparent Silicone Resin
Solid Solid Solid Solid Solid Solid Oil Solid Solid Composition
Thermoplastic Temperature(.degree. C.) 70 60 68 60 70 60 --*.sup.1
--*.sup.1 --*.sup.2 --*.sup.1 70 Thermosetting Temperature(.degree.
C.) 180 180 180 180 180 180 --*.sup.3 --*.sup.3 -- --*.sup.3 200
Heat Reduction 24 h 99 97 98 98 99 99 -- -- -- -- 99 Resistance
Rate(%) of 168 h 98 97 98 99 98 98 -- -- -- -- 98 Light
Transmittance Flexibility Tensile Modulus (MPa) 0.08 1.32 -- 0.01
0.1 0.01 -- -- -- -- 0.06 Elongation Percentage 110 20 -- 160 100
130 -- -- -- -- 110 (%) *.sup.1Not Evaluated Because of Oil State
*.sup.2Not Plasticized *.sup.3Not Cured *.sup.4Ratio of Hydrosilyl
Group of organohydrogenpolysiloxane relative to the residual
hydrosilyl group in Silicone Resin Precursor (X/Y) [Molar
Ratio]
[0404] As is clear from Table 3, the silicone resin compositions of
Examples 5 to 10 and Comparative Example 10 have both thermoplastic
and thermosetting properties. Moreover, the silicone resin
compositions of Examples 5 to 10 have a low thermosetting
temperature, i.e., 180.degree. C. Furthermore, the silicone resin
compositions of Examples 5 and 8 to 10 have excellent elongation,
and the silicone resin composition of Example 6 has excellent
tensile modulus.
[0405] On the other hand, the silicone resin compositions of
Comparative Examples 6 to 9 do not have both thermoplastic and
thermosetting properties.
[0406] To be specific, the silicone resin composition of
Comparative Example 6 does not contain an alkenyl group-containing
polysiloxane, and therefore hydrosilylation reaction did not occur,
and the obtained silicone resin composition did not become solid at
room temperature, but became liquid at room temperature. That is,
the silicone resin composition of Comparative Example 6 does not
have thermoplastic properties.
[0407] In the silicone resin composition of Comparative Example 7,
a molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
in the cage octasilsesquioxane as a whole, as an average value, was
7:1, and the number of moles of the hydrosilyl group was small, and
therefore the reaction degree of the cage octasilsesquioxane and
the alkenyl group-containing polysiloxane was reduced, causing a
low molecular weight of the obtained silicone resin composition,
and the obtained silicone resin composition did not become solid at
room temperature, but became liquid at room temperature. That is,
the silicone resin composition of Comparative Example 7 did not
have thermoplastic properties.
[0408] In the silicone resin composition of Comparative Example 8,
the molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
in the cage octasilsesquioxane as a whole, as an average value, was
5:3, and the number of moles of the hydrosilyl group of the cage
octasilsesquioxane was large, and the obtained silicone resin
composition did not exhibit thermoplastic properties.
[0409] In the silicone resin composition of Comparative Example 9,
the hydrosilylation catalyst was not blended, and therefore
hydrosilylation reaction did not occur, and the silicone resin
precursor could not be obtained. Moreover, the silicone resin
composition did not become solid at room temperature, but became
liquid at room temperature. That is, the silicone resin composition
of Comparative Example 9 did not have thermoplastic properties.
[0410] The sample of Comparative Example 10 had both thermoplastic
and thermosetting properties, but compared with the samples of
Examples 5 to 10, its thermosetting temperature was high, i.e.,
200.degree. C.
[0411] This is probably because the organohydrogenpolysiloxane was
not blended therein, and therefore cage octasilsesquioxane were
cured by hydrolysis between each other due to moisture in the air
and self-condensation, which caused a short crosslinking
distance.
3 Examples and Comparative Examples Corresponding to the Third
Invention Group
Examples 11 to 16 and Comparative Examples 11 to 15
Example 11
[0412] 0.36 g of cage octasilsesquioxane (in formula (2), R.sup.2
ratio=methyl group:hydrogen (molar ratio)=6:2) of Synthesis Example
1, 0.24 g of a polysiloxane containing alkenyl groups at both ends
(in formula (3), R.sup.3 was methyl group, R.sup.4 was vinyl group,
"a" was 8; number average molecular weight 800), 1 g of toluene,
and 0.1 .mu.L of a solution of platinum-divinylsiloxane complex
(hydrosilylation catalyst, toluene solution, platinum concentration
2 mass %) were blended, and the mixture was stirred at 50.degree.
C. for 15 hours. The silicone resin precursor was obtained in this
manner. The molar ratio (=vinyl group/hydrosilyl group) of the
vinyl group of the polysiloxane containing alkenyl groups at both
ends to the hydrosilyl group of the cage octasilsesquioxane was
0.91.
[0413] Thereafter, to the obtained silicone resin precursor, 0.03 g
(5.0 parts by mass relative to 100 parts by mass of a total amount
of cage octasilsesquioxane and polysiloxane containing alkenyl
groups at both ends) of a straight chain siloxane-containing
polysiloxane (in formula (8), R.sup.5 was methyl group, R.sup.6 was
vinyl group, b=120, c=10; number average molecular weight 10000,
vinyl group content 0.98 mmol/g) was blended, and the mixture was
stirred.
[0414] The ratio (X/Y) of the vinyl group of the straight chain
siloxane-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.49.
[0415] Thereafter, toluene was distilled off, thereby producing a
cloudy solid silicone resin composition.
[0416] The straight chain siloxane-containing polysiloxane content
in the silicone resin composition was 4.8 mass %.
Example 12
[0417] A silicone resin precursor was obtained in the same manner
as in Example 11, except that the blending amount of the straight
chain siloxane-containing polysiloxane (in formula (8), R.sup.5 was
methyl group, R.sup.6 was vinyl group, b=120, c=10; number average
molecular weight 10000, vinyl group content 0.98 mmol/g) was
changed from 0.03 g to 0.14 g (23.2 parts by mass relative to 100
parts by mass of a total amount of cage octasilsesquioxane and the
polysiloxane containing alkenyl groups at both ends), and then a
cloudy solid silicone resin composition was obtained.
[0418] The ratio (X/Y) of the vinyl group of the straight chain
siloxane-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 2.29, and the straight chain siloxane-containing
polysiloxane content in the silicone resin composition was 18.8
mass %.
Example 13
[0419] A silicone resin precursor was obtained in the same manner
as in Example 11, except that instead of 0.03 g of the straight
chain siloxane-containing polysiloxane (in formula (8), R.sup.5 was
methyl group, R.sup.6 was vinyl group, b=120, c=10; number average
molecular weight 10000, vinyl group content 0.98 mmol/g), 0.03 g
(5.0 parts by mass relative to 100 parts by mass of a total amount
of cage octasilsesquioxane and polysiloxane containing alkenyl
groups at both ends) of the straight chain siloxane-containing
polysiloxane (in formula (8), R.sup.5 was methyl group, R.sup.6 was
vinyl group, b=131, c=2; number average molecular weight 10000,
vinyl group content 0.13 mmol/g) was blended, and then a cloudy
solid silicone resin composition was obtained.
[0420] The ratio (X/Y) of the vinyl group of the straight chain
siloxane-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.065, and the straight chain siloxane-containing
polysiloxane content was 4.8 mass %.
Example 14
[0421] A silicone resin precursor was obtained in the same manner
as in Example 11, except that instead of 0.36 g of cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.3 g of
cage octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=5.5:2.5) of Synthesis Example 2 was
blended, and then a cloudy solid silicone resin composition was
obtained.
[0422] The ratio (X/Y) of the vinyl group of the straight chain
siloxane-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.39, and the straight chain siloxane-containing
polysiloxane content in silicone resin composition was 5.2 mass
%.
Example 15
[0423] A silicone resin precursor was obtained in the same manner
as in Example 11, except that instead of 0.24 g of the polysiloxane
containing alkenyl groups at both ends (in formula (3), R.sup.3 was
methyl group, R.sup.4 was vinyl group, a=8; number average
molecular weight 800), 0.6 g of the polysiloxane containing alkenyl
groups at both ends (in formula (3), R.sup.3 was methyl group,
R.sup.4 was vinyl group, a=25; number average molecular weight
2000) was blended, and then a cloudy solid silicone resin
composition was obtained.
[0424] The ratio (X/Y) of the vinyl group of the straight chain
siloxane-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.49, and the straight chain siloxane-containing
polysiloxane content in the silicone resin composition was 3.0 mass
%.
Example 16
[0425] A silicone resin precursor was obtained in the same manner
as in Example 11, except that instead of 0.03 g of the straight
chain siloxane-containing polysiloxane (in formula (8), R.sup.5 was
methyl group, R.sup.6 was vinyl group, b=120, c=10; number average
molecular weight 10000, vinyl group content 0.98 mmol/g), 0.03 g (5
parts by mass relative to 100 parts by mass of a total amount of
cage octasilsesquioxane and polysiloxane containing alkenyl groups
at both ends) of the branched siloxane-containing polysiloxane (in
formula (9), R.sup.7 was methyl group and vinyl group; number
average molecular weight 2400, vinyl group content 0.4 to 0.6
mmol/g) was blended, and then a cloudy solid silicone resin
composition was obtained.
[0426] The ratio (X/Y) of the vinyl group in the branched
siloxane-containing polysiloxane relative to the residual
hydrosilyl group in the silicone resin precursor was, in a molar
ratio, 0.25, and the branched siloxane-containing polysiloxane
content in the silicone resin composition was 4.8 mass %.
Comparative Example 11
[0427] A silicone resin precursor was obtained in the same manner
as in Example 11, except that instead of 0.24 g of the polysiloxane
containing alkenyl groups at both ends (in formula (3), R.sup.3 was
methyl group, R.sup.4 was vinyl group, a=8; number average
molecular weight 800), 0.24 g of a polysiloxane (in formula (3),
R.sup.3 and R.sup.4 were both methyl groups, a=8; number average
molecular weight 800) that does not contain alkenyl groups was
blended, and then a cloudy oil silicone resin composition was
obtained.
[0428] The ratio (X/Y) of the alkenyl group (X) of the polysiloxane
containing alkenyl groups at side chain relative to the residual
hydrosilyl group (Y) in the silicone resin precursor was, in a
molar ratio, 0.04, and the polysiloxane containing alkenyl groups
at side chain content in the silicone resin composition was 4.8
mass %.
Comparative Example 12
[0429] A silicone resin precursor was obtained in the same manner
as in Example 11, except that instead of 0.36 g of the cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.72 g of
the cage octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=7:1) of Comparative Synthesis Example
1 was blended, and then a cloudy oil silicone resin composition was
obtained.
[0430] The ratio (X/Y) of the alkenyl group (X) of the polysiloxane
containing alkenyl groups at side chain relative to the residual
hydrosilyl group (Y) in the silicone resin precursor was, in a
molar ratio, 0.49, and the polysiloxane containing alkenyl groups
at side chain content in the silicone resin composition was 3.0
mass %.
Comparative Example 13
[0431] A silicone resin precursor was obtained in the same manner
as in Example 11, except that instead of 0.36 g of the cage
octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=6:2) of Synthesis Example 1, 0.24 g of
the cage octasilsesquioxane (in formula (2), R.sup.2 ratio=methyl
group:hydrogen (molar ratio)=5:3) of Comparative Synthesis Example
2 was blended, and then a transparent solid (gel) silicone resin
composition was obtained.
[0432] The ratio (X/Y) of the alkenyl group (X) of the polysiloxane
containing alkenyl groups at side chain relative to the residual
hydrosilyl group (Y) in the silicone resin precursor was, in a
molar ratio, 0.49, and the polysiloxane containing alkenyl groups
at side chain content in the silicone resin composition was 5.9
mass %.
Comparative Example 14
[0433] The same operation as in Example 11 was performed, except
that a solution of platinum-divinylsiloxane complex
(hydrosilylation catalyst, toluene solution, platinum concentration
2 mass %) was not blended; and a silicone resin composition was
obtained without obtaining a silicone resin precursor. That is, to
the cage octasilsesquioxane and the polysiloxane containing alkenyl
groups at both ends, a straight chain siloxane-containing
polysiloxane was blended, and a cloudy oil silicone resin
composition was obtained.
Comparative Example 15
[0434] A silicone resin precursor was obtained in the same manner
as in Example 11, except that the straight chain
siloxane-containing polysiloxane (in formula (8), R.sup.5 was
methyl group, R.sup.6 was vinyl group, b=120, c=10; number average
molecular weight 10000, vinyl group content 0.98 mmol/g) was not
blended, and this was regarded as a silicone resin composition. The
silicone resin composition was cloudy solid state.
Evaluation
1. Thermoplastic and Thermosetting Properties
[0435] Behaviors when heated of the silicone resin compositions of
Examples 11 to 16 and Comparative Examples 11 to 15 were
evaluated.
[0436] To be specific, samples having a size of 1 cm square were
made from the silicone resin compositions of Examples 11 to 16, and
Comparative Examples 13 and 15. The samples were placed on a hot
plate and heated to 30 to 200.degree. C., and their thermoplastic
temperature and thermosetting temperature were measured with visual
observation. The results are shown in Table 4.
[0437] The samples of Comparative Example 13 was solid, but did not
soften by heat, and therefore its thermoplastic temperature could
not be evaluated. The sample of Comparative Example 13 was solid,
and therefore its thermosetting temperature could not be
evaluated.
[0438] On the other hand, the samples of Comparative Examples 11,
12, and 14 were liquid, and therefore their thermoplastic
temperatures could not be evaluated. Also, a predetermined amount
of (about 1 mL) the samples of Comparative Examples 11, 12, and 14
were applied on a hot plate, and heated to 30 to 200.degree. C. The
samples were observed, but because the samples were not cured by
heating, their thermosetting temperatures could not be
evaluated.
2. Heat Resistance (Reduction Rate of Light Transmittance)
[0439] Transmittance of light at a wavelength of 450 nm of samples
made as described above of Examples 11 to 16 and Comparative
Example 15 was measured by a spectrophotometer (U4100, manufactured
by Hitachi High-Technologies Corporation).
[0440] Thereafter, the samples were placed in a hot air dryer of
200.degree. C. for a predetermined period. Then, after elapses of
24 hours and 168 hours, the samples were taken out from the hot air
dryer, and transmittance of the taken samples of light at a
wavelength of 450 nm was measured.
[0441] Then, the reduction rates (=(light transmittance after
placement in the dryer/light transmittance before placement in the
dryer).times.100) of the light transmittance of the samples were
calculated. The results are shown in Table 4.
3. Flexibility (Tensile Modulus and Elongation Percentage)
[0442] Samples made as described above of Examples 11 to 16 and
Comparative Example 15 were evaluated for their (silicone resin
composition) tensile modulus and elongation percentage.
[0443] To be specific, samples having a thickness of 600 .mu.m were
made from the silicone resin compositions of Examples 11 to 16 and
Comparative Example 15, and then placed in a hot air dryer of
200.degree. C. The samples were taken out after an elapse of 24
hours, and their tensile modulus at 25.degree. C., and elongation
percentage at 25.degree. C. were measured using a universal testing
machine (autograph, manufactured by Shimadzu Corporation). The
results are shown in Table 4.
TABLE-US-00004 TABLE 4 Example .cndot. Comparative Example
Comparative Comparative Comparative Comparative Comparative Example
11 Example 12 Example 13 Example 14 Example 15 Example 16 Example
11 Example 12 Example 13 Example 14 Example 15 Cage Synthesis
Example .cndot. Synthesis Synthesis Synthesis Synthesis Synthesis
Synthesis Synthesis Comparative Comparative Synthesis Synthesis
octasilsesquioxane Comparative Synthesis Example 1 Example 1
Example 1 Example 2 Example 1 Example 1 Example 1 Synthesis
Synthesis Example 1 Example 1 Example Example 1 Example 2
R.sup.2/Methyl 6:2 6:2 6:2 5.5:2.5 6:2 6:2 6:2 7:1 5:3 6:2 6:2
Group:Hydrogen(Molar Ratio) Blending Amount(g) 0.36 0.36 0.36 0.3
0.36 0.36 0.36 0.15 0.45 0.36 0.36 Polysiloxane R.sup.3 Methyl
Methyl Methyl Methyl Methyl Methyl Methyl Methyl Methyl Methyl
Methyl containing Group Group Group Group Group Group Group Group
Group Group Group alkenyl R.sup.4 Vinyl Group Vinyl Group Vinyl
Group Vinyl Group Vinyl Group Vinyl Group Methyl Vinyl Group Vinyl
Group Vinyl Group Vinyl Group groups at Group both ends Number
average molecular 800 800 800 800 2000 800 800 800 800 800 800
weight Blending Amount(g) 0.24 0.24 0.24 0.24 0.6 0.24 0.24 0.24
0.24 0.24 0.24 Vinyl Group/Hydrosilyl Group(Molar Ratio) 0.91 0.91
0.91 0.91 0.91 0.91 -- 0.90 0.91 0.91 0.91 Hydrosilylation Catalyst
Solution of Solution of Solution of Solution of Solution of
Solution of Solution of Solution of Solution of -- Solution of
Platinum- Platinum- Platinum- Platinum- Platinum- Platinum-
Platinum- Platinum- Platinum- Platinum- Divinyl- Divinyl- Divinyl-
Divinyl- Divinyl- Divinyl- Divinyl- Divinyl- Divinyl- Divinyl-
siloxane siloxane siloxane siloxane siloxane siloxane siloxane
siloxane siloxane siloxane Complex Complex Complex Complex Complex
Complex Complex Complex Complex Complex Polysiloxane Straight chain
R.sup.5 Methyl Methyl Methyl Methyl Methyl -- Methyl Methyl Methyl
Methyl -- containing siloxane Group Group Group Group Group Group
Group Group Group alkenyl R.sup.6 Vinyl Group Vinyl Group Vinyl
Group Vinyl Group Vinyl Group -- Vinyl Group Vinyl Group Vinyl
Group Vinyl Group groups at Branched siloxane R.sup.7 -- -- -- --
-- Methyl -- -- -- -- side chain Group/ Vinyl Group Vinyl Group
Content (mmol/g) 0.98 0.98 0.13 0.98 0.98 -- 0.98 0.98 0.98 0.98
Vinyl Equivalent (Eq/kg) -- -- -- -- -- 0.4~0.6 -- -- -- -- Number
average molecular 10000 10000 10000 10000 10000 2400 10000 10000
10000 10000 weight Blending Amount(g) 0.03 0.14 0.03 0.03 0.03 0.03
0.03 0.03 0.03 0.03 Side chain alkenyl group 4.8 18.8 4.8 5.2 3.0
4.8 4.8 3.0 5.9 5.2 containing polysiloxane content relative to
Silicone Resin Composition (mass %) Ratio of alkenyl group
(X/Y)*.sup.4 0.49 2.29 0.065 0.39 0.49 0.25 0.04 0.49 0.49 --
Evaluation on State at Room Temperature Transparent Transparent
Transparent Transparent Transparent Transparent Cloudy Transparent
Transparent Cloudy Oil Transparent Silicone Resin Solid Solid Solid
Solid Solid Solid Oil Oil Solid Solid Composition Thermoplastic
Temperature(.degree. C.) 60 60 60 65 60 60 --*.sup.1 --*.sup.1
--*.sup.2 --*.sup.1 70 Thermosetting Temperature(.degree. C.) 160
160 165 160 170 150 --*.sup.3 --*.sup.3 -- --*.sup.3 200 Heat
Reduction 24 h 98 98 98 98 99 99 -- -- -- -- 99 Resistance Rate (%)
of 168 h 98 97 98 97 98 98 -- -- -- -- 98 Light Transmittance
Flexibility Tensile Modulus (MPa) 0.37 0.42 0.19 0.41 0.32 0.24 --
-- -- -- 0.06 Elongation Percentage 53 47 60 43 59 38 -- -- -- --
110 (%) *.sup.1Not Evaluated Because of Oil State *.sup.2Not
Plasticized *.sup.3Not Cured *.sup.4Ratio of alkenyl group in side
chain alkenyl group containing polysiloxane relative to residual
hydrosilyl group in silicone resin precursor (X/Y)[Molar Ratio]
[0444] As is clear from Table 4, the silicone resin compositions of
Examples 11 to 16 and Comparative Example 15 have both
thermoplastic and thermosetting properties. Moreover, the silicone
resin compositions of Examples 11 to 16 have a low thermosetting
temperature, i.e., 150 to 170.degree. C., and have excellent
tensile modulus and elongation.
[0445] On the other hand, the silicone resin compositions of
Comparative Examples 11 to 14 do not have both thermoplastic and
thermosetting properties.
[0446] To be specific, the silicone resin composition of
Comparative Example 11 does not contain the polysiloxane containing
alkenyl groups at both ends, and therefore hydrosilylation reaction
did not occur, and the obtained silicone resin composition did not
become solid at room temperature, but became liquid at room
temperature. That is, the silicone resin composition of Comparative
Example 11 did not have thermoplastic properties.
[0447] In the silicone resin composition of Comparative Example 12,
a molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
in the cage octasilsesquioxane as a whole, as an average value, was
7:1, and the number of moles of the hydrosilyl group was small, and
therefore the reaction degree of the cage octasilsesquioxane and
the polysiloxane containing alkenyl groups at both ends was
reduced, causing a low molecular weight of the obtained silicone
resin composition, and the obtained silicone resin composition did
not become solid at room temperature, but became liquid at room
temperature. That is, the silicone resin composition of Comparative
Example 12 did not have thermoplastic properties.
[0448] In the silicone resin composition of Comparative Example 13,
the molar ratio of monovalent hydrocarbon group:hydrogen in R.sup.2
in the cage octasilsesquioxane as a whole, as an average value, was
5:3, and the number of moles of the hydrosilyl group of the cage
octasilsesquioxane was large, and the obtained silicone resin
composition did not exhibit thermoplastic properties.
[0449] In the silicone resin composition of Comparative Example 14,
the hydrosilylation catalyst was not blended, and therefore
hydrosilylation reaction did not occur, and the silicone resin
precursor could not be obtained. Moreover, the silicone resin
composition did not become solid at room temperature, but became
liquid at room temperature. That is, the silicone resin composition
of Comparative Example 14 did not have thermoplastic
properties.
[0450] The silicone resin composition of Comparative Example 15 had
both thermoplastic and thermosetting properties, but compared with
the silicone resin compositions of Examples 11 to 16, the
thermosetting temperature was high, i.e., 200.degree. C., and the
tensile modulus was low.
[0451] This is probably because the polysiloxane containing alkenyl
groups at side chain was not blended therein, and therefore cage
octasilsesquioxane were cured by hydrolysis between each other due
to moisture in the air and self-condensation, which caused a short
crosslinking distance.
[0452] While the illustrative embodiments of the present invention
are provided in the above description, such is for illustrative
purpose only and it is not to be construed as limiting in any
manner. Modifications and variations of the present invention that
will be obvious to those skilled in the art are to be covered by
the following claims.
* * * * *