U.S. patent application number 11/437664 was filed with the patent office on 2006-11-23 for lens-forming silicone resin composition and silicone lens.
This patent application is currently assigned to SHIN-ETSU CHEMICAL CO., LTD.. Invention is credited to Katsuyuki Imazawa, Tsutomu Kashiwagi, Toshio Shiobara.
Application Number | 20060264583 11/437664 |
Document ID | / |
Family ID | 37449107 |
Filed Date | 2006-11-23 |
United States Patent
Application |
20060264583 |
Kind Code |
A1 |
Kashiwagi; Tsutomu ; et
al. |
November 23, 2006 |
Lens-forming silicone resin composition and silicone lens
Abstract
Silicone resin compositions comprising (A) an organopolysiloxane
containing at least two aliphatic unsaturated bonds and having a
viscosity of 100-1,000,000 mPas at 25.degree. C., (B) an
organohydrogenpolysiloxane having at least three silicon-bonded
hydrogen atoms (SiH groups) in the form of HR.sup.6.sub.2SiO-, and
(C) a platinum group metal base catalyst cure into colorless
transparent parts which are useful lenses.
Inventors: |
Kashiwagi; Tsutomu;
(Annaka-shi, JP) ; Shiobara; Toshio; (Annaka-shi,
JP) ; Imazawa; Katsuyuki; (Annaka-shi, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
SHIN-ETSU CHEMICAL CO.,
LTD.
Tokyo
JP
|
Family ID: |
37449107 |
Appl. No.: |
11/437664 |
Filed: |
May 22, 2006 |
Current U.S.
Class: |
525/478 ; 528/15;
528/31; 528/32 |
Current CPC
Class: |
C08L 83/04 20130101;
C08L 83/00 20130101; C08L 83/04 20130101; G02B 1/041 20130101; C08G
77/20 20130101; G02B 1/041 20130101; C08G 77/12 20130101; C08L
83/04 20130101 |
Class at
Publication: |
525/478 ;
528/015; 528/031; 528/032 |
International
Class: |
C08L 83/04 20060101
C08L083/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 23, 2005 |
JP |
2005-149293 |
Claims
1. A lens-forming silicone resin composition comprising (A) an
organopolysiloxane containing at least two aliphatic unsaturated
bonds in a molecule and having a viscosity of at least 100 mPa s at
250C, (B) an organohydrogenpolysiloxane having in a molecule at
least three hydrogensiloxy structures of the following formula:
##STR14## wherein R is a monovalent hydrocarbon group, and (C) a
platinum group metal base catalyst, the composition becoming
colorless and transparent when cured.
2. The composition of claim 1 wherein component (A) is an
organopolysiloxane having the general formula (1): ##STR15##
wherein R.sup.1 is each independently a substituted or
unsubstituted monovalent hydrocarbon group, R.sup.2 is each
independently an aliphatic unsaturation-free, substituted or
unsubstituted monovalent hydrocarbon group, k and m each are 0 or a
positive integer, k+m is such a number that the organopolysiloxane
has a viscosity of 100 to 1,000,000 mPas at 25.degree. C.
3. The composition of claim 1 wherein component (A) is an
organopolysiloxane of resin structure having the average
compositional formula:
(R.sup.3SiO.sub.1.5).sub.x(R.sup.r.sub.2SiO).sub.y(R.sup.5.sub.3SiO.sub.0-
.5).sub.z wherein R.sup.3, R.sup.4 and R.sup.5 are each
independently a substituted or unsubstituted monovalent hydrocarbon
group, 2 to 45 mol % of the entire monovalent hydrocarbon groups
being vinyl, x, y and z representative of the molar ratio of
corresponding siloxane units are such numbers that x/(x+y+z) is 0.3
to 0.95, y/(x+y+z) is 0.05 to 0.50, and z/(x+y+z) is 0 to 0.05.
4. The composition of claim 1 wherein component (B) is an
organohydrogenpolysiloxane having the average compositional
formula: H.sub.a(R.sup.6).sub.bSiO.sub.(4-a-b)/2 (1) wherein
R.sup.6 is each independently an aliphatic unsaturation-free,
substituted or unsubstituted monovalent hydrocarbon group, a and b
are positive numbers satisfying 0.001.ltoreq.a <2,
0.7.ltoreq.b.ltoreq.2, and 0.8.ltoreq.a+b .ltoreq.3, said
organohydrogenpolysiloxane having at least three silicon-bonded
hydrogen atoms (SiH groups) in the form of HR.sup.6.sub.2SiO- in a
molecule.
5. A silicone lens obtained by molding and curing the composition
of claim 1.
6. The silicone lens of claim 5 for use in an LED device.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This non-provisional application claims priority under 35
U.S.C. .sctn.119(a) on Patent Application No. 2005-149293 filed in
Japan on May 23, 2005, the entire contents of which are hereby
incorporated by reference.
TECHNICAL FIELD
[0002] This invention relates to a silicone resin composition of
the addition cure type for forming lenses, and more particularly,
to a silicone resin composition with ease of molding for forming
substantially surface tack-free silicone lenses having improved
transparency. It also relates to a silicone lens obtained by
molding and curing the silicone resin composition and suited for
use in LED devices.
BACKGROUND ART
[0003] Lenses for use in light-emitting diode (LED) devices are
mass manufactured by mechanical forming such as injection molding.
Although prior art lenses are molded using thermoplastic resins
such as acrylic resins and polycarbonate resins, the currently
increasing power of LED devices invites the problem that
thermoplastic resins' heat resistance and discoloration resistance
are short.
[0004] Also, lead-free solders are often used nowadays. Since the
lead-free solders have a higher melting temperature than
conventional solders, optical devices are usually soldered to
substrates while heating at a temperature of 260.degree. C. or
higher. When soldering at such high temperature, lenses of prior
art thermoplastic resins can no longer be used because the lenses
will deform or yellow due to the heat.
[0005] Under the circumstances, a number of studies have been made
on the use of silicone resins in the lenses associated with LED or
the like. However, when lenses are manufactured from silicone
resins by forming techniques such as injection molding, the
silicone resins which are thermosetting resins need a long molding
time as compared with prior art thermoplastic resins. Slow curing
leaves a possibility of weld-line formation. There is a need to
eliminate these deficiencies.
[0006] The references pertinent to the present invention include
JP-A 2000-231002 corresponding to U.S. Pat. No. 6,285,513, JP-A
2000-17176, and JP-A 2004-221308.
DISCLOSURE OF THE INVENTION
[0007] An object of the invention is to provide a lens-forming
silicone resin composition that has overcome the drawbacks of the
prior art and offers a satisfactory cured lens within a brief
molding time; and a silicone lens obtained by molding and curing
the composition.
[0008] The inventors have found that a lens-forming silicone resin
composition comprising the following components attains the above
and other objects while reducing the molding time.
[0009] The present invention provides a lens-forming silicone resin
composition comprising as essential components,
[0010] (A) an organopolysiloxane containing at least two aliphatic
unsaturated bonds in a molecule and having a viscosity of at least
100 mPas at 25.degree. C.,
[0011] (B) an organohydrogenpolysiloxane having in a molecule at
least three hydrogensiloxy structures of the following formula:
##STR1## wherein R is a monovalent hydrocarbon group, and
[0012] (C) a platinum group metal base catalyst, the composition
becoming colorless and transparent when cured.
[0013] Also contemplated herein is a silicone lens obtained by
molding and curing the silicone resin composition.
BENEFITS OF THE INVENTION
[0014] By molding and curing the silicone resin composition of the
invention, silicone lenses can be manufactured within a brief
time.
BRIEF DESCRIPTION OF THE DRAWING
[0015] FIG. 1 schematically illustrates the shape of a lens molded
from the compositions of Examples and Comparative Examples, FIG.
1(1) being a plane view and FIG. 1(2) being a side view.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Component A
[0016] Corponent (A) is any of organopolysiloxanes containing in a
molecule at least two aliphatic unsaturated bonds, typically
alkenyl groups of 2 to 8 carbon atoms, preferably 2 to 6 carbon
atoms, such as vinyl and allyl. They should also have a viscosity
of at least 100 mPas at 25.degree. C., preferably at least 1,000
mPa s at 25.degree. C. Of these, linear organopolysiloxanes,
represented by the following formula (1), containing at least one
alkenyl group on the silicon atom at either end of the molecular
chain and having a viscosity of at least 100 mPas at 25.degree. C.
are desired for efficient working and curing.
[0017] When lenses are manufactured by a molding machine such as an
injection molding machine, a resin with too low a viscosity will
penetrate into ejector pin-mold junctures and parting lines, giving
rise to the trouble that lenses are formed with burrs or the
ejector pins become inoperable even when the mold is opened. For
this reason, a viscosity of at least 100 mPa-s is necessary. If the
viscosity exceeds 1,000,000 mPa s during mixing, thorough mixing by
a static mixer may be impeded. Thus the viscosity should preferably
be less than or equal to 1,000,000 mPas.
[0018] It is noted that the linear organopolysiloxane may contain a
small proportion of branched structure (trifunctional siloxane
units) in the molecular chain. ##STR2##
[0019] Herein R.sup.1 is each independently a substituted or
unsubstituted monovalent hydrocarbon group, R.sup.2 is each
independently an aliphatic unsaturation-free, substituted or
unsubstituted monovalent hydrocarbon group, k and m each are 0 or a
positive integer, k+m is such a number that the organopolysiloxane
has a viscosity of 100 to 1,000,000 mPas at 25.degree. C.
[0020] The monovalent hydrocarbon groups represented by R.sup.1 are
preferably those of 1 to 10 carbon atoms, more preferably of 1 to 6
carbon atoms, for example, alkyl groups such as methyl, ethyl,
propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl,
hexyl, cyclohexyl, octyl, nonyl and decyl; aryl groups such as
phenyl, tolyl, xylyl and naphthyl; aralkyl groups such as benzyl,
phenylethyl and phenylpropyl; alkenyl groups such as vinyl, allyl,
propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl and octenyl;
and substituted forms of the foregoing in which some or all
hydrogen atoms are substituted by halogen atoms (fluoro, bromo,
chloro) or cyano groups, including halogenated alkyl groups such as
chloromethyl, chloropropyl, bromoethyl and trifluoropropyl, and
cyanoethyl.
[0021] The monovalent hydrocarbon groups represented by R.sup.2 are
also preferably those of 1 to 10 carbon atoms, more preferably of 1
to 6 carbon atoms, examples of which are the same as exemplified
above for R.sup.1; with the proviso that alkenyl groups are
excluded.
[0022] The subscripts k and m each are 0 or a positive integer,
typically satisfying 5.ltoreq.k+m.ltoreq.10,000. Preferably k and m
are positive integers satisfying 10.ltoreq.k+m.ltoreq.2,000 and 0
<k/(k+m).ltoreq.0.2.
[0023] Illustrative, non-limiting examples of the
organopolysiloxane (A) are given below. ##STR3##
[0024] In these formulae, t is an integer of 8-2000. ##STR4##
[0025] In these formulae, k and m are as defined above.
[0026] Also employable as component (A) are organopolysiloxanes of
resin structure. The preferred organopolysiloxanes of resin
structure are vinyl-containing organopolysiloxanes having the
average compositional formula:
(R.sup.3SiO.sub.1.5).sup.x(R.sup.4.sub.2SiO).sub.y(R.sup.5.sub.-
3SiO.sub.0.5).sup.z wherein R.sup.3, R.sup.4 and R.sup.5 are each
independently a substituted or unsubstituted monovalent hydrocarbon
group, 2 to 45 molt of the entire monovalent hydrocarbon groups
being vinyl, x, y and z representative of the molar ratio of
corresponding siloxane units are such numbers that x/(x+y+z) is
from 0.3 to 0.95, y/(x+y+z) is from 0.05 to 0.50, and z/(x+y+z) is
from 0 to 0.05.
[0027] The monovalent hydrocarbon groups represented by R.sup.3,
R.sup.4 and R.sup.5 include those of 1 to 10 carbon atoms,
preferably 1 to 8 carbon atoms, for example, alkyl groups such as
methyl, ethyl and propyl, alkenyl groups such as vinyl, and aryl
groups such as phenyl. Halogenated forms of these hydrocarbon
groups are also included. It is requisite that 2 to 45 mol %,
especially 5 to 30 mol % of the entire monovalent hydrocarbon
groups be vinyl. If the number of vinyl groups is less than 2 mol
%, the addition reaction with component (B) to be described later
results in a low crosslinking density, failing to form molded parts
with improved mechanical strength. If the number of vinyl groups is
more than 45 mol %, molded parts may become brittle.
[0028] The subscripts x, y and z representative of the molar ratio
of corresponding siloxane units are numbers as defined above, and
preferably such numbers that x/(x+y+z) is from 0.4 to 0.8,
y/(x+y+z) is from 0.1 to 0.5, and z/(x+y+z) is from 0 to 0.04.
[0029] These vinyl-containing organopolysiloxanes can be obtained
by co-hydrolytic condensation of a mixture of two or more
halosilanes or alkoxysilanes corresponding to the respective
siloxane units.
[0030] Illustrative examples of the respective siloxane units in
the above average compositional formula include monovinylsiloxane,
monomethylsiloxane, monoethylsiloxane, monophenylsiloxane,
divinylsiloxane, phenylvinylsiloxane, methylphenylsiloxane,
diphenylsiloxane, dimethylsiloxane, trivinylsiloxane,
divinylmethylsiloxane, divinylphenylsiloxane,
vinyldimethylsiloxane, vinylphenylmethylsiloxane,
trimethylsiloxane, dimethylphenylsiloxane, methyldiphenylsiloxane,
triphenylsiloxane, etc., and substituted siloxanes in which
hydrogen atoms of organic groups are substituted by halogen or the
like.
[0031] It is noted that the inclusion of SiO.sub.2 units is
acceptable as long as this does not compromise the objects of the
invention.
Component B
[0032] Component (B) is an organohydrogenpolysiloxane which serves
as a crosslinking agent such that addition reaction takes place
between SiH groups in component (B) and vinyl groups in component
(A) to form a cured product. It may be any of
organohydrogenpolysiloxanes having in a molecule at least three
hydrogen atoms each of which is bonded to the silicon atom present
at the terminal of the molecular chain, i.e., at least three
hydrogensiloxy structures of the following formula: ##STR5##
wherein R is a monovalent hydrocarbon group which is as defined
below for R.sup.6.
[0033] Preferred are organohydrogenpolysiloxanes having the average
compositional formula: H.sub.a(R.sup.6).sub.bSiO.sub.(4-a-b)/2 (2)
wherein R.sup.6 is each independently an aliphatic
unsaturation-free, substituted or unsubstituted monovalent
hydrocarbon group, a and b are positive numbers satisfying 0.001
5.ltoreq.a<2, 0.7.ltoreq.b.ltoreq.2, and 0.8s a+b s 3. The
organohydrogenpolysiloxanes should have at least three, typically 3
to about 100, preferably 3 to about 30, silicon-bonded hydrogen
atoms (SiH groups) in the form of HR.sup.6.sub.2SiO- in a
molecule.
[0034] More particularly, R.sup.6 in formula (2) may be the same or
different and is a substituted or unsubstituted monovalent
hydrocarbon group free of aliphatic unsaturation, preferably having
1 to 10 carbon atoms, more preferably 1 to 7 carbon atoms, for
example, lower alkyl groups such as methyl, aryl groups such as
phenyl, and the like, as exemplified above for R.sup.2 in formula
(1). The subscripts a and b are positive numbers satisfying
0.001.ltoreq.a<2, 0.7.ltoreq.b .ltoreq.2, and 0.8.ltoreq.a+b
.ltoreq.3, and preferably 0.05.ltoreq.a.ltoreq.1,
0.8.ltoreq.b.ltoreq.2, and 1.ltoreq.a+b.ltoreq.2.7. The location of
silicon-bonded hydrogen atoms is not particularly limited, and may
be either an end or an intermediate of the molecular chain. The
inclusion of at least three silicon-bonded hydrogen atoms at ends
of the molecular chain is typical.
[0035] Examples of the organohydrogenpolysiloxane include
tris(dimethylhydrogensiloxy)methylsilane,
tris(dimethylhydrogensiloxy)phenylsilane, copolymers of
(CH.sub.3).sub.2HSiO.sub.1/2 units and SiO.sub.4/2 units, and
copolymers of (CH.sub.3).sub.2HSiO.sub.1/2 units, SiO.sub.4/2
units, and (C.sub.6H.sub.5)SiO.sub.3/2 units.
[0036] Compounds of the structure shown below are also useful.
##STR6##
[0037] The molecular structure of the organohydrogenpolysiloxane
may be linear, cyclic, branched or three-dimensional network.
Preferably, the number of silicon atoms per molecule or the degree
of polymerization is about 3 to about 1,000, preferably about 3 to
about 300.
[0038] Such an organohydrogenpolysiloxane is generally prepared
through hydrolysis of chlorosilanes such as R.sup.6SiHCl.sub.2,
(R.sup.6).sub.3SiCl, (R.sup.6).sub.2SiCl.sub.2 and
(R.sup.6).sub.2SiHCl, wherein R.sup.6 is as defined above, or
hydrolysis of chlorosilanes and subsequent equilibration of the
resultant siloxane.
[0039] The organohydrogenpolysiloxane may be compounded in an
effective amount for component (A) to cure, preferably in such
amounts that the molar ratio of SiH groups to the total of alkenyl
groups (e.g., vinyl) in component (A) is 0.1-4.0:1, more preferably
1.0-3.0:1, and most preferably 1.2-2.8:1. A molar ratio of less
than 0.1 may allow curing reaction to proceed little and make it
difficult to produce cured silicone. If the molar ratio is more
than 4.0, more SiH groups may be left unreacted in the cured
composition which will change its physical properties with
time.
Component C
[0040] The platinum group metal-based catalyst is compounded for
inducing addition cure reaction to the inventive composition.
Platinum, palladium and rhodium base catalysts are included. Of
these, platinum base catalysts are preferred from the economical
standpoint. Examples include platinum, platinum black and
chloroplatinic acid, and more specifically
H.sub.2PtCl.sub.6mH.sub.2O, K.sub.2PtCl.sub.6,
KHPtCl.sub.6mH.sub.2O, K.sub.2PtCl.sub.4,
K.sub.2PtCl.sub.4mH.sub.2O, and PtO.sub.2mH.sub.2O wherein m is a
positive integer, and complexes thereof with hydrocarbons (e.g.,
olefins), alcohols and vinyl-containing organopolysiloxanes. They
may be used alone or in admixture. The catalyst (C) may be used in
a catalytic amount, specifically in an amount to give about 0.1 to
1,000 ppm, more preferably about 0.5 to 200 ppm of platinum group
metal based on the weight of components (A) and (B) combined.
[0041] The silicone resin composition of the invention is prepared
by intimately mixing the above-mentioned components. Most often,
the composition is stored in two packages so that no cure occurs.
On use, the two packages are combined, allowing the composition to
cure. The composition may, of course, be of one-package type if a
small amount of a cure inhibitor such as acetylene alcohol is
added.
[0042] Optionally, well-known additives including antioxidants,
ultrafine silica such as Aerosil.RTM., and inorganic fillers having
a matching refractive index with the silicone resin may be
compounded for the purposes of improving mechanical strength,
adjusting a coefficient of expansion or the like as long as this is
not detrimental to transparency.
[0043] When lenses are manufactured by injection molding or
otherwise forming the silicone resin composition, the composition
of two-package type is more productive because rapid reaction
occurs after mixing of the two packages. For mixing, an ordinary
mixing device such as a static mixer is used. The mixture is
directly fed to an injection molding machine and pressure molded in
the mold. The molding conditions are not particularly limited and
include a temperature of 120 to 180.degree. C. and a time of about
30 to 90 seconds although exact molding conditions depend on the
curability of the silicone resin composition. The composition may
be post-cured at 100 to 200.degree. C. for 30 minutes to 20 hours
if desired.
[0044] The silicone resin composition of the invention cures into
colorless transparent parts and is thus suitable for the
manufacture of lenses including lenses for LED devices, laser
pickup lenses and high-temperature resin lenses.
EXAMPLE
[0045] Examples and Comparative Examples are given below for
further illustrating the invention, but the invention is not
limited thereto. In Examples, all parts are by weight, and the
viscosity is as measured at 25.degree. C. by a rotational
viscometer. Abbreviations Me, Vi, and Ph stand for methyl, vinyl,
and phenyl, respectively.
Reference Example 1
[0046] With vigorous stirring, a mixture of 698 parts of
phenyltrichlorosilane, 169 parts of methylvinyldichlorosilane, 194
parts of dimethyldichlorosilane and 530 parts of toluene was added
dropwise to 2,500 parts of water over 60 minutes. Stirring was
continued for a further 60 minutes, after which the toluene
solution was washed with water until neutral. After water washing,
the toluene solution was adjusted to a siloxane concentration of
25%. 0.42 part of potassium hydroxide was added to the toluene
solution which was heated under reflux for 5 hours for
polymerization. Then 13.8 parts of trimethylchlorosilane was added
to the solution, followed by stirring for 60 minutes at room
temperature, neutralization of the alkali, and removal of residual
silanol groups. This was filtered and heated under vacuum for
distilling off the toluene, leaving a transparent vinyl-bearing
organopolysiloxane.
Example 1
[0047] To 50 parts of a polysiloxane (VF) having the formula (i)
were added 50 parts of a vinylmethylsiloxane (VMQ) of resin
structure consisting of 50 mol % SiO.sub.2 units, 42.5 mol %
(CH.sub.3).sub.3SiO.sub.0.5 units and 7.5 mol % Vi.sub.3SiO.sub.0.5
units, an amount to give a 1.5-fold molar amount of SiH groups
relative to the total of vinyl groups in the VF and VMQ components
of an organohydrogenpolysiloxane having the formula (ii) and 0.05
part of an octyl alcohol-modified chloroplatinic acid solution. By
thoroughly mixing the ingredients, a silicone resin composition was
prepared. ##STR7##
Example 2
[0048] A silicone resin composition was prepared by mixing 100
parts of the vinyl-bearing organopolysiloxane obtained in Reference
Example 1 with 30 parts of an organohydrogenpolysiloxane having the
following formula and 0.05 part of a 1% octyl alcohol-modified
chloroplatinic acid solution. ##STR8##
Example 3
[0049] A silicone resin composition was prepared as in Example 2
except that the crosslinking agent was replaced by 25 parts of a
crosslinking agent of the following formula. ##STR9##
Example 4
[0050] A silicone resin composition was prepared as in Example 2
except that the crosslinking agent was replaced by 24.9 parts of a
crosslinking agent of the following formula. ##STR10##
Comparative Example 1
[0051] A silicone resin composition was prepared as in Example 2
except that the crosslinking agent was replaced by 33 parts of a
crosslinking agent of the following formula. ##STR11##
Comparative Example 2
[0052] A silicone resin composition was prepared as in Example 2
except that the crosslinking agent was replaced by 40 parts of a
crosslinking agent of the following formula. ##STR12##
Comparative Example 3
[0053] A silicone resin composition was prepared as in Example 2
except that the crosslinking agent was replaced by 30 parts of a
crosslinking agent of the following formula. ##STR13##
[0054] From the silicone resin compositions of Examples 1-4 and
Comparative Examples 1-3, lenses were molded using a 20-ton
injection molding machine equipped with a multiple-cavity mold
capable of forming 16 parts in one shot. The lens has a dome shape
as shown in FIG. 1. The resin composition was molded under
conditions: an injection pressure of 20 MPas, a curing temperature
of 150.degree. C., and a curing time of 90 seconds, after which the
cured-resin or lenses were taken out of the mold cavities. It was
observed how hard the cured resin was when taken out of the mold
cavity and how smoothly the cured resin could be released from the
mold cavity. Additionally, the hardness of the cured resin or lens
as taken out was measured at room temperature according to JIS 6253
using a Type D durometer. The lenses were post-cured at 150.degree.
C. for 4 hours, after which the hardness was measured again.
[0055] The test methods and criteria are shown below.
Cure
[0056] Full: strength (or resin hardness) enough to withstand
practical handling [0057] Under: strength (or resin hardness)
insufficient to withstand practical handling Mold release
[0058] Good: smooth release from the mold
[0059] Poor: non-smooth release from the mold TABLE-US-00001 TABLE
1 Example 1 2 3 4 Cure Full Full Full Full Mold release Good Good
Good Good Resin hardness, Type D 15 50 50 50 Post-cured resin
hardness, Type D 30 75 75 75
[0060] TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 Cure Under
Under Under Mold release Poor Poor Poor Resin hardness, Type D UM
UM UM Post-cured resin hardness, Type D 30 75 75 * UM:
unmeasurable
[0061] Japanese Patent Application No. 2005-149293 is incorporated
herein by reference.
[0062] Although some preferred embodiments have been described,
many modifications and variations may be made thereto in light of
the above teachings. It is therefore to be understood that the
invention may be practiced otherwise than as specifically described
without departing from the scope of the appended claims.
* * * * *