U.S. patent application number 10/889032 was filed with the patent office on 2004-12-23 for fine particle of aluminum hydroxide for filling resin and resin composition using the same.
This patent application is currently assigned to SHOWA DENKO K.K.. Invention is credited to Onishi, Akira, Takahashi, Yukihiko.
Application Number | 20040259979 10/889032 |
Document ID | / |
Family ID | 29273410 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040259979 |
Kind Code |
A1 |
Onishi, Akira ; et
al. |
December 23, 2004 |
Fine particle of aluminum hydroxide for filling resin and resin
composition using the same
Abstract
A fine particle of aluminum hydroxide is disclosed, comprising a
particulae aluminum hydroxide X having a specific surface area of
1.0 m.sup.2/g or less and a secondary particle size of 35 to 150
.mu.m, a particulate aluminum hydroxide Y having a specific surface
area of 1.0 m.sup.2/g or less and a secondary particle size of 10
to 35 .mu.m and a particulate aluminum hydroxide Z having a
specific area of 3.0 m.sup.2/g or less and a secondary particle
size of 0.5 to 10 .mu.m, in a compositional mass ratio falling in
the area surrounded by four points of Point a, Point .beta., Point
.gamma. and Point .delta. including the lines in the ternary
composition diagram shown in FIG. 1. By this fine particle of
aluminum hydroxide, a fine particle of aluminum hydroxide and a
resin composition comprising the fine particle of aluminum
hydroxide, which can be reduced in the viscosity at the filling in
a resin and attain high filling and when filled in a thermosetting
resin, can be shortened in the curing time, can be provided.
Inventors: |
Onishi, Akira; (Kanagawa,
JP) ; Takahashi, Yukihiko; (Kanagawa, JP) |
Correspondence
Address: |
SUGHRUE, MION, ZINN, MACPEAK & SEAS, PLLC
2100 Pennsylvania Avenue, N.W.
Washington
DC
20037-3213
US
|
Assignee: |
SHOWA DENKO K.K.
|
Family ID: |
29273410 |
Appl. No.: |
10/889032 |
Filed: |
July 13, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10889032 |
Jul 13, 2004 |
|
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|
09904558 |
Jul 16, 2001 |
|
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|
6786964 |
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60240831 |
Oct 17, 2000 |
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Current U.S.
Class: |
523/171 ;
106/401; 524/437 |
Current CPC
Class: |
C01P 2006/12 20130101;
C08K 3/22 20130101; C04B 26/02 20130101; C08K 2003/2227 20130101;
C04B 20/008 20130101; C04B 14/303 20130101; C04B 14/303 20130101;
C04B 26/02 20130101; C04B 14/303 20130101; C04B 2111/545 20130101;
C01P 2004/61 20130101; C01P 2004/51 20130101; C01F 7/02 20130101;
C01P 2004/62 20130101 |
Class at
Publication: |
523/171 ;
106/401; 524/437 |
International
Class: |
C09D 005/29; C08K
003/10; C04B 014/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 17, 2000 |
JP |
P2000-216488 |
Claims
What is claimed is:
1. A fine particle of aluminum hydroxide for filling in a resin,
which has properties such that when 200 parts by weight of said
fine particle of aluminum hydroxide is filled into 100 parts by
weight of an unsaturated polyester resin having a viscosity of 10
poises at 20.degree. C. measured by a Brookfield viscometer, the
viscosity is less than 200 poises in the measurement at 35.degree.
C. by a Brookfield viscometer.
2. The fine particle of aluminum hydroxide for filling in a resin
according to claim 1, when 150 parts by weight of said fine
particle of aluminum hydroxide is filled into a resin composition
comprising 100 parts by weight of another unsaturate polyester
resin having a viscosity of 18 poises at 25.degree. C. measured by
a Brookfield viscometer and 2 parts by weight of methyl ethyl
ketone peroxide, the curing time until the viscosity becomes
immeasurable due to the curing of resin is less than 20 minutes in
the measurement at 35.degree. C. by a Brookfield viscometer.
3. The fine particle of aluminum hydroxide for filling in a resin
according to any one of claim 1 or 2, wherein the fine particle of
aluminum hydroxide is obtained by blending at least three
components (ternary system).
4. The fine particle of aluminum hydroxide for filling in a resin
according to any one of claim 1 or 2, wherein the fine particle of
aluminum hydroxide comprises a particulate aluminum hydroxide X
having a secondary particle size of 35 to 150 .mu.m, a particulate
aluminum hydroxide Y having a secondary particle size of 10 to 35
.mu.m and a particulate aluminum hydroxide Z having a secondary
particle size of 0.5 to 10 .mu.m.
5. A resin composition comprising the fine particles of aluminum
hydroxide claimed in any one of claim 1 or 2.
6. A resin composition comprising the fine particles of aluminum
hydroxide claimed in any one of claims 1 or 2, wherein the
viscosity of the resin composition measured at 35.degree. C. by a
Brookfield type viscometer is less than 200 poises.
7. An artificial marble comprising the fine particle of aluminum
hydroxide claimed in any one of claims 1 or 2.
8. A bath tub comprising the artificial marble claimed in claim
7.
9. A kitchen counter comprising the artificial marble claimed in
claim 7.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
09/904,558 filed Jul. 16, 2001, which is an application filed under
35 U.S.C. .sctn.111(a) claiming benefit pursuant to 35 U.S.C.
.sctn.119(e)(1) of the filing date of the Provisional Application
60/240,831 filed Oct. 17, 35 U.S.C. .sctn.111(b), the disclosures
of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a fine particle of aluminum
hydroxide for filling in a resin, which is used as a flame
retardant or the like in plastic, rubber and the like, and also
relates to a resin composition comprising the fine particle of
aluminum hydroxide.
BACKGROUND OF THE INVENTION
[0003] The aluminum hydroxide has been conventionally used over the
wide range as a filler for filling in rubbers and plastics, for
example, as a flame retardant in a thermoplastic resin, a rubber
and an epoxy resin or as a toning filler in a thermosetting resin
such as unsaturated polyester resin and acrylic resin.
[0004] In the case of using the aluminum hydroxide as a flame
retardant, the flame resistance is more improved as the amount of
aluminum hydroxide filled is larger. However, if the amount filled
is increased, the moldability or kneading torque increases and in
turn the molding temperature increases, as a result, the aluminum
hydroxide disadvantageously undergoes partial dehydration and
foaming. In the case of filling the aluminum hydroxide into a
thermosetting resin, the material cost may be lowered by increasing
the amount filled, however, a problem arises, such as deterioration
in the mold-workability or reduction in the curing speed.
[0005] A resin composition obtained by filling fine particles of
aluminum hydroxide in an unsaturated polyester resin, acrylic resin
or the like is especially used as an artificial marble for the
constructive material of bath tub, kitchen counter and the like.
However, in order to bring out a texture (solemnity) close to
natural marble, a large amount of fine particles of aluminum
hydroxide must be filled into the resin.
[0006] For solving these problems, various techniques have been
heretofore disclosed, for example, (1) a method of using a mixture
with agglomerated coarse particles as a primary particle or fine
particles obtained by grinding the coarse particles (see,
JP-B-5-48782 (the term "JP-B" as used herein means an "examined
Japanese patent publication)) and (2) a method of grinding a
particulate aluminum hydroxide specified in the particle diameter
or soda content to obtain aluminum hydroxide having a small
specific surface area (see, JP-B-4-6648 and JP-B-6-49573) are
known.
[0007] The technique (1) above has a problem in that coarse
particles used alone precipitate at the molding and this causes
reduction in the surface smoothness or in the strength of the
molded article and when used in combination with fine particles,
the curing time is prolonged as the specific surface area is
increased. In the technique (2), the curing time is also prolonged
due to increase in the specific surface area after the grinding or
cracking of agglomerated particles and when these particles are
used alone, the amount filled is limited because the particles are
fine.
[0008] In order to improve the filling property into a resin, a
surface treatment with a fatty acid, a silane coupling agent or the
like is often performed.
SUMMARY OF THE INVENTION
[0009] Under these circumstances, the object of the present
invention is to improve conventional fine particles of aluminum
hydroxide for filling in a resin such as plastic and rubber and
provide a fine particle of aluminum hydroxide which can be reduced
in the viscosity at the filling into a resin to attain high filling
and when filled into a thermosetting resin, can ensure reduction in
the curing time and more increase in the productivity. The object
of the present invention includes providing a resin composition
comprising the fine particle of alumina hydroxide.
[0010] As a result of extensive investigations to develop an
aluminum hydroxide having the above-described preferred properties,
the present inventors have found that when a fine particle of
aluminum hydroxide is obtained by blending at least two components
(binary system), preferably three components (ternary system), the
object of the present invention can be attained. The present
invention has been accomplished based on this finding. More
specifically, the present invention provides the following
inventions.
[0011] 8 1] A fine particle of aluminum hydroxide for filling in a
resin, which has properties such that when 200 parts by weight of
the fine particle of aluminum hydroxide is filled into 100 parts by
weight of an unsaturated polyester resin (Rigolac 2004WM-2,
produced by Showa Highpolymer Co., Ltd.), the viscosity can be less
than 200 poises in the measurement at 35.degree. C. by a Brookfield
viscometer and that when 150 parts by weight of the fine particle
of aluminum hydroxide is filled into a resin composition comprising
100 parts by weight of another unsaturated polyester resin
(Polylite TP-123, produced by Dai-Nippon Ink & Chemicals, Inc.)
and 2 parts by weight of methyl ethyl ketone peroxide, the curing
time until the viscosity becomes immeasurable due to the curing of
resin can be less than 20 minutes in the measurement at 35.degree.
C. by a Brookfield viscometer.
[0012] [2] A fine particle of aluminum hydroxide comprising a
particulate aluminum hydroxide X having a BET specific surface area
of 1.0 m.sup.2/g or less and a secondary particle size of 35 to 150
.mu.m, a particulate aluminum hydroxide Y having a BET specific
surface area of 1.0 m.sup.2/g or less and a secondary particle size
of 10 to 35 .mu.m, and a particulate aluminum hydroxide Z having a
BET specific area of 3.0 m.sup.2/g or less and a secondary particle
size of 0.5 to 10 .mu.m, in a compositional mass ratio falling in
the area surrounded by four points of Point .alpha.
(X:Y:Z=47.5:25.0:27.5), Point .beta. (X:Y:Z=47.5:50.0:2.5), Point
.gamma. (X:Y:Z=82.5:0.0:17.5) and Point .delta.
(X:Y:Z=72.5:0.0:27.5) including the lines in the ternary
composition diagram shown in FIG. 1 where the entire is assumed to
be 100% by mass.
[0013] [3] A fine particle of aluminum hydroxide comprising a
particulate aluminum hydroxide X having a BET specific surface area
of 1.0 m.sup.2/g or less and a secondary particle size of 35 to 150
.mu.m, a particulate aluminum hydroxide Y having a BET specific
surface area of 1.0 m.sup.2/g or less and a secondary particle size
of 10 to 35 .mu.m, and a particulate aluminum hydroxide Z having a
BET specific area of 3.0 m.sup.2/g or less and a secondary particle
size of 0.5 to 10 .mu.m, in a compositional mass ratio falling in
the area surrounded by four points of Point A
(X:Y:Z=50.0:25.0:25.0), Point B (X:Y:Z=50.0:45.0:5.0), Point C
(X:Y:Z=80.0:0.0:20.0) and Point D (X:Y:Z=75.0:0.0:25.0) including
the lines in the ternary composition diagram shown in FIG. 2 where
the entire is assumed to be 100% by mass.
[0014] [4] The fine particle of aluminum hydroxide as described in
[2] or [3], wherein the particulate aluminum hydroxide X has a
secondary particle size of 50 to 150 .mu.m, the particulate
aluminum hydroxide Y has a secondary particle size of 10 to 25
.mu.m and the particulate aluminum hydroxide Z has a secondary
particle size of 0.5 to 8 .mu.m.
[0015] [5] A resin composition comprising the fine particle of
aluminum hydroxide described in any one of [1] to [4].
[0016] [6] A resin composition comprising the fine particle of
aluminum hydroxide described in any one of [1] to [4], wherein the
viscosity measured at 35.degree. C. by a Brookfield type viscometer
is less than 200 poises.
[0017] [7] A resin composition comprising the fine particle of
aluminum hydroxide described in any one of [1] to [4], which is a
resin composition for forming an artificial marble.
[0018] [8] A resin composition comprising the fine particle of
aluminum hydroxide described in any one of [1] to [4], which
comprises at least one resin selected from the group consisting of
an unsaturated polyester resin, an acrylic resin, a vinyl ester
resin and an epoxy resin.
[0019] [9] A resin composition comprising the fine particle of
aluminum hydroxide described in any one of [1] to [4], which is a
cured resin composition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows a ternary composition diagram relating to a
fine particle of aluminum hydroxide according to one example of the
present invention.
[0021] FIG. 2 shows a ternary composition diagram relating to a
fine particle of aluminum hydroxide according to one example of the
present invention.
[0022] FIG. 3 shows a ternary composition diagram relating to a
fine particle of aluminum hydroxide prepared in one of the
Examples.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention is described in detail below.
[0024] The fine particle of aluminum hydroxide of the present
invention is a fine particle of aluminum hydroxide for filling in a
resin, which has properties such that when 200 parts by weight of
the fine particle of aluminum hydroxide is filled into 100 parts by
weight of an unsaturated polyester resin having a viscosity of 10
poises at 20.degree. C. measured by a Brookfield viscometer
(Rigolac 2004WM-2, produced by Showa Highpolymer Co., Ltd.), the
viscosity of the resulting resin composition can be less than 200
poises in the measurement at 35.degree. C. by a Brookfield
viscometer and that when 150 parts by weight of the fine particle
of aluminum hydroxide and 2 parts by weight of methyl ethyl ketone
peroxide are filled into 100 parts by weight of another unsaturated
polyester resin having a viscosity of 18 poises at 25.degree. C.
measured by a Brookfield viscometer (Polylite TP-123, produced by
Dai-Nippo Ink & Chemicals, Inc.), the curing time of the
resulting resin composition until the viscosity becomes
immeasurable due to the curing of resin can be less than 20 minutes
in the measurement at 35.degree. C. by a Brookfield viscometer.
[0025] The present inventors have found that the surface of a fine
particle of aluminum hydroxide is covered with many OH groups,
therefore, when incorporated into a curable resin or the like, the
fine particle of aluminum hydroxide inhibits the curing reaction of
the curable resin and prolongs the curing reaction. Based on this
knowledge, the fine particle of aluminum hydroxide having the
above-described properties has been found out.
[0026] The present inventors further studied on the BET specific
area and secondary particle size of the fine particle of aluminum
oxide, the filling composition, the amount filled and the like so
as to find out a fine particle of aluminum hydroxide which does not
inhibit the curing reaction of a resin, as a result, a specific
preferred fine particle of aluminum hydroxide and the composition
blending ratio thereof have been found out.
[0027] More specifically, the fine particle of aluminum hydroxide
of the present invention is characterized in that when a coarse
particulate aluminum hydroxide X having a secondary particle size
of 35 to 150 .mu.m, preferably from 50 to 150 .mu.m, and a specific
surface area measured by the nitrogen adsorption method (BET), of
1.0 m.sup.2/g or less, preferably 0.5 m.sup.2/g or less, a medium
particulate aluminum hydroxide Y having a secondary particle size
of 10 to 35 .mu.m, preferably from 10 to 25 .mu.m, and a specific
surface area of 1.0 m.sup.2/g or less, preferably 0.8 m.sup.2/g or
less, and a fine particulate aluminum hydroxide Z having a
secondary particle size of 0.5 to 10 .mu.m, preferably from 0.5 to
8 .mu.m, and a specific area of 3.0 m.sup.2/g or less, preferably
2.0 m.sup.2/g or less, are blended in a predetermined compositional
mass ratio, the viscosity at the filling in a resin can be reduced
and the curing time at the filling into a thermosetting resin can
be shortened.
[0028] In the present invention, the measurement of viscosity at
35.degree. C. by a Brookfield viscometer is performed according to
JIS K6901, 4.4.1. That is, a rotor is rotated in a sample using a
synchronous generator and the viscous resistance torque thereof is
measured by the spring balance. More specifically, 500 ml of a
sample is charged into a beaker and when the sample temperature
reached 35.+-.0.5.degree. C., the rotor of the viscometer is dipped
to the marked line. After allowing to stand for about 5 minutes,
the rotor is rotated for 3 minutes and the value is read. The
measured value is multiplied by a multiplier decided according to
the rotor used and the rotational frequency, whereby the viscosity
is determined.
[0029] The "curing time until the viscosity becomes immeasurable
due to curing of the resin" as used in the present invention means
a time period until the rotor stops rotating and the viscosity
cannot be measured when 100 parts by weight of the unsaturated
polyester resin for use in the present invention and 2 parts by
weight of methyl ethyl ketone peroxide are mixed and the viscosity
is measured by the above-described method.
[0030] The predetermined compositional mass ratio of the fine
particle of aluminum hydroxide is, for example, in the case of a
fine particle by a ternary system blending, a ratio such that in
the ternary composition diagram shown in FIG. 1, assuming that the
entire is 100% by mass, a coarse particulate aluminum hydroxide X,
a medium particulate aluminum hydroxide Y and a fine particulate
aluminum particle Z are blended to fall in the area surrounded by
four points of Point .alpha. (X:Y:Z=47.5:25.0:27.5), Point .beta.
(X:Y:Z=47.5:50.0:2.5), Point .gamma. (X:Y:Z=82.5:0.0:17.5) and
Point .delta. (X:Y:Z=72.5:0.0:27.5) including the lines
(hereinafter, the blending ratio is shown in the order of X:Y:Z).
In FIG. 1, Y can be present in an amount of 5% mass, and the
particulate aluminum hydroxide particles are blended to fall in the
area surrounded by four points of Point .alpha., Point .beta.,
Point .epsilon. (X:Y:Z=79:5:16) and Point .phi.
(X:Y:Z=67.5:5:27.5). The blending ratio by mass preferably falls,
in the ternary composition diagram shown in FIG. 2 attached hereto,
in the area surrounded by four points of Point A (50.0:25.0:25.0),
Point B (50.0:45.0:5.0), Point C (80.0:0.0:20.0) and Point D
(75.0:0.0:25.0) including the lines. In FIG. 2, Y can be present in
an amount of 5% by mass, and the particulate aluminum hydroxide
particles are blended to fall in the area surrounded by four points
of Point A, Point B, Point R (X:Y:Z=76.7:5:18.3) and Point S
(X:Y:Z=70:5:25).
[0031] The viscosity as used herein is a viscosity (unit: poises)
determined when a resin composition is prepared by filling 200
parts by mass of the above-described fine particle of aluminum
hydroxide into 100 parts by mass of a resin (for example, a curable
resin such as unsaturated polyester resin) and measured at
35.degree. C. by a Brookfield viscometer.
[0032] The curing time can be evaluated by the time period until
the viscosity becomes immeasurable due to curing of the resin when
150 parts by mass of the fine particle of aluminum hydroxide and 2
parts by mass of a radical generator such as methyl ehtyl ketone
peroxide compound are filled into 100 parts by mass of a curable
resin (for example, unsaturated polyester resin) and the viscosity
of the resulting resin composition is measured at 35.degree. C. by
a Brookfield viscometer.
[0033] The aluminum hydroxide for use in the present invention is
an alumina trihydrate represented by the formula:
Al.sub.2O.sub.3.3H.sub.2O, and the purity thereof is not
particularly limited.
[0034] The coarse particulate aluminum hydroxide X for use in the
present invention is an agglomerated particle precipitated by the
Bayer's process and has a secondary particle size of 35 to 150
.mu.m, preferably from 50 to 150 .mu.m, and a specific surface area
measured by the nitrogen adsorption method (BET), of 1.0 m.sup.2/g
or less, preferably 0.5 m.sup.2/g or less. If the secondary
particle size is less than 35 .mu.m, since this is close to the
particle size of the medium particulate aluminum hydroxide Y
described later, the effect of reducing the viscosity when the
particles are blended is low, whereas if the second particle size
exceeds 150 .mu.m, when the particles are filled in a resin, the
strength disadvantageously decreases to an extreme extent. If the
specific surface area exceeds 1.0 m.sup.2/g, the curing after the
filling into a resin takes a long time and this is not
preferred.
[0035] The secondary particle size indicates a particle size of an
agglomerate, an aggregate or a combined body formed by the
aggregation of aluminum hydroxide fine particles. The measurement
of the secondary particle size is performed in an ordinary manner
using sieving, optical microscope, Coulter counter or laser
scattering diffraction method. Among these, the laser scattering
diffraction method is preferably used.
[0036] The medium particulate aluminum hydroxide Y for use in the
present invention can be obtained by grinding the agglomerate of
the coarse particulate aluminum hydroxide X using a known dry or
wet grinder of which kind is not particularly limited or by adding
the above-described agglomerate to an alkali solution of aluminic
acid to form a slurry and heating the slurry to a temperature of 60
to 90.degree. C., thereby partially dissolving and separating at
their grain boundaries to primary particles. The secondary particle
size thereof is from 10 to 35 .mu.m, preferably from 10 to 25
.mu.m, and the specific surface area is 1.0 m.sup.2/g or less,
preferably 0.8 m.sup.2/g or less. If the secondary particle size is
less than 10 .mu.m, the particle size is close to that of the fine
particulate aluminum hydroxide Z described later and therefore, the
effect of reducing the viscosity when the particles are blended is
low, whereas if the secondary particle size exceeds 35 .mu.m, the
particle size is close to that of the coarse particulate aluminum
hydroxide X described above and therefore, the effect of reducing
the viscosity when the particles are blended is low. If the
specific surface area exceeds 1.0 m.sup.2/g, the curing after the
filling into a resin takes a long time and this is not
preferred.
[0037] The fine particulate aluminum hydroxide Z for use in the
present invention can be obtained by grinding the agglomerate of
agglomerated particles having a secondary particle size smaller
than that of the coarse particulate aluminum hydroxide X obtained
by the Bayer's process, using a conventionally known dry or wet
grinder of which kind is not particularly limited or by adding the
above-described agglomerate to an alkali solution of aluminic acid
to form a slurry and heating the slurry to a temperature of 60 to
90.degree. C., thereby partially dissolving and separating at their
grain boundaries to primary particles. The secondary particle size
thereof is from 0.5 to 10 .mu.m, preferably from 0.5 to 8 .mu.m,
and the specific surface area is 3.0 m.sup.2/g or less, preferably
2.0 m.sup.2/g or less. If the secondary particle size exceeds 10
.mu.m, the particle size is close to that of the medium particulate
aluminum hydroxide (Y) described above and therefore, the effect of
reducing the viscosity when the particles are blended is low,
whereas if the secondary particle size is less than 0.5 .mu.m, the
handleability disadvantageously deteriorates to an extreme extent.
If the specific surface area exceeds 3.0 m.sup.2/g, the curing
after the filling into a resin takes a long time and this is not
preferred.
[0038] The present invention further provides a resin composition
comprising the fine particle of aluminum hydroxide having the
above-described properties. The resin composition comprising the
fine particle of aluminum hydroxide of the present invention is not
limited in the composition thereof as long as the viscosity
measured at 35.degree. C. by a Brookfield viscometer is less than
200 poises. The resins capable of satisfying this viscosity
requirement can be used without limit.
[0039] In the present invention, when, for example, a ternary
system fine particle of aluminum hydroxide (fine particles each
containing three components of X, Y and Z) is filled into a resin,
the resin is not limited as described above, however, examples of
the resin include unsaturated polyester resin, acrylic resin, vinyl
ester resin, epoxy resin, xylene formaldehyde resin, guanamine
resin, diallyl phthalate resin, phenol resin, furan resin,
polyimide resin, melamine resin and urea resin. Among these,
preferred are unsaturated polyester resin, acrylic resin, vinyl
ester resin and epoxy resin.
[0040] The resin composition of the present invention is preferably
a resin composition for forming an artificial marble and for
example, the resin for forming an artificial marble is at least one
selected from unsaturated polyester resin, acrylic resin, vinyl
ester resin and epoxy resin.
[0041] The method for blending the fine particle of aluminum oxide
is not particularly limited and a conventionally known method may
be used therefor, such as air blender, V-shape blender, rocking
blender and Henschel mixer.
[0042] The fine particle of aluminum hydroxide of the present
invention may be surface-treated by a conventionally known method
and the method is not limited.
[0043] The present invention also provides a cured product of the
above-described curable resin composition comprising the fine
particle of aluminum hydroxide.
BEST MODE FOR CARRYING OUT THE INVENTION
[0044] The present invention is described in greater detail below
by referring to the Examples, however, the present invention should
not be construed as being limited to these Examples.
EXAMPLE 1 to 5
[0045] At least two components of a coarse particulate aluminum
hydroxide X having a secondary particle size of 84 .mu.m and a
specific surface area of 0.2 m.sup.2/g, a medium particulate
aluminum hydroxide Y having a secondary particle size of 16.5 .mu.m
and a specific surface area of 0.5 m.sup.2/g and a fine particulate
aluminum hydroxide Z having a secondary particle size of 5.9 .mu.m
and a specific surface area of 1.6 m.sup.2/g were blended at a
compositional ratio shown in Table 1 by a V-shape blender for 10
minutes to obtain fine particles each comprising a blend of
particulate aluminum hydroxides.
[0046] To 100 parts by mass of commercially available unsaturated
polyester resin (Rigolac 2004WM-2, Showa Highpolymer Co., Ltd.),
200 parts by mass of the thus-obtained fine particle comprising a
blend of particulate aluminum hydroxides was filled and the
viscosity thereof was measured at 35.degree. C. by a Brookfield
viscometer. Separately, 150 parts by mass of the fine particle
comprising a blend of particulate aluminum hydroxides was filled
into 100 parts by mass of a commercially available unsaturated
polyester resin (Polylite TP-123, produced by Dainippon Ink &
Chemicals, Inc.) and as a curing catalyst, 2 parts by mass of a
methyl ethyl ketone compound (Trigonox 63, produced by Kayaku Akzo
Co.) was added thereto. The viscosity of the resulting composition
was continuously measured at 35.degree. C. by a Brookfield
viscometer and the time period from the initiation of the
measurement until the viscosity became immeasurable due to the
curing of resin, namely, the curing time was measured.
COMPARATIVE EXAMPLES 1 to 12
[0047] At least two of the same components as those used in
Examples 1 to 5 were mixed at the compositional ratio shown in
Table 1 and then evaluation was performed in the same manner as in
Examples 1 to 5.
COMPARATIVE EXAMPLE 13
[0048] A fine particle comprising a blend of particulate aluminum
hydroxides was prepared using the same compositional ratio and the
same components as in Example 1 except that a medium particulate
aluminum hydroxide Y2 having a secondary particle size of 16.4
.mu.m and a specific surface area of 1.4 m.sup.2/g was used, and
the evaluation thereof was performed in the same manner as in
Example 1.
COMPARATIVE EXAMPLE 14
[0049] A fine particle comprising a blend of particulate aluminum
hydroxides was prepared using the same compositional ratio and the
same components as in Example 1 except that a medium particulate
aluminum hydroxide Z2 having a secondary particle size of 6.4 .mu.m
and a specific surface area of 3.2 m.sup.2/g was used, and the
evaluation thereof was performed in the same manner as in Example
1.
[0050] FIG. 3 shows compositional mass ratios of the particulate
aluminum hydroxides (X, Y, Z) used in the Examples and Comparative
Examples.
1 TABLE 1 Secondary Particle Size [.mu.m] and Specific Surface Area
[m.sup.2/g] of Each Component Compositional Ratio [mass %]
Evaluation Results Abbreviation Coarse Medium Fine Coarse Medium
Fine Viscosity Curing Time in FIGURE Particle Particle Particle
Particle Particle Particle [poises] [min] Example 1 A 84.0 .mu.m,
16.5 .mu.m, 5.9 .mu.m, 50 25 25 130 15 0.2 m.sup.2/g 0.5 m.sup.2/g
1.6 m.sup.2/g Example 2 B 50 45 5 170 11 Example 3 C 80 0 20 170 15
Example 4 D 75 0 25 140 18 Example 5 E 60 20 20 150 15 Comparative
F 45 25 30 150 65 Example 1 Comparative G 45 40 15 190 43 Example 2
Comparative H 45 55 0 200 10 Example 3 Comparative I 50 50 0 200 10
Example 4 Comparative J 60 35 5 200 9 Example 5 Comparative K 70 20
10 210 10 Example 6 Comparative L 85 0 15 200 14 Example 7
Comparative M 70 0 30 140 25 Example 8 Comparative N 60 10 30 140
25 Example 9 Comparative O 50 10 40 140 37 Example 10 Comparative P
30 50 20 280 98 Example 11 Comparative Q 90 10 0 470 8 Example 12
Comparative -- 16.4 .mu.m, 50 25 25 240 44 Example 13 1.4 m.sup.2/g
Comparative -- 16.5 .mu.m, 6.4 .mu.m, 50 25 25 260 44 Example 14
0.5 m.sup.2/g 3.2 m.sup.2/g
Industrial Applicability
[0051] As apparent from Table 1, by blending particulate aluminum
hydroxides having specific secondary particle sizes and specific
surface areas at a specific ratio, when the fine particle of
aluminum hydroxide is filled in plastic, rubber or the like, the
viscosity is reduced and high filling can be attained. At the same
time, in the case of filling the fine particle into a thermosetting
resin, the curing time is very short and the productivity can be
more increased. Thus, the fine particle of aluminum hydroxide
according to the present invention can improve the properties
required for the filling in a resin and accordingly, the industrial
effect thereof is very high.
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