DESCRIPTION
Title of Invention: POLYOL COMPOSITION FOR PRODUCING POLYURETHANE
RESIN COMPOSITION
5 Technical Field
[0001]
The present invention relates to a polyol composition
for producing a polyurethane resin composition, a polyurethane
resin composition containing the polyol composition, an
10 electrical or electronic component resin-sealed with the resin
composition, and the like.
Background Art
[0002]
15 Recent years have seen progress in the development of
highly dense and highly integrated electrical or electronic
components, and thus there is strong demand for increased
reliability for the components. In response to the demand,
attempts have been made to prevent electrical or electronic
20 components, such as printed boards, from being affected by
external environmental factors (physical factors, such as drops
and vibrations; ultraviolet rays; chemical factors, such as
moisture and salts; etc.) by sealing the electrical or electronic
1 components with resin. For example, polyurethane-based resin has
25 been used as an electric insulating sealing material for
I
I
I electrical or electronic components because of its excellent
i 1 properties, such as flexibility, abrasion resistance, cold
curability, and electrical characteristics.
1 [00031
I 3 0 Polyurethane-based resin has been used not only as an
11
electric insulating sealing material, but also as a coating agent,
an adhesive, or the like, in broader fields such . a. s electric,
electronics, automobile, civil engineering, and architecture.
35 Cltatlon List
Patent Literature
[0004]
PTL I.: JP2010-150474A
PTL 2: JP2010-180384A
5 PTL 3: JP2000-219806A
PTL 4: JP2005-132093A
Smary of Invention
Technical Problem
10 [00051
In the preparation of polyurethane-based resin for use
in electrical or electronic components, an inorganic filler,
typically a metal hydroxide, may be added in order to impart
thermal radiation properties or flame retardancy. However, adding
15 an inorganic filler leads to a smaller proportion of the polyol
and polyisocyanate, thereby increasing the likelihood of foaming
or poor curing when even a slight amount of water is present. In
polyurethane-based resin, foaming reduces the waterproofing
properties, electrical insulation, and thermal radiation
20 properties; thus, foaming is particularly not desirable in the
use of such resin in electric insulating sealing materials.
[0006]
Patent Literature 1 uses a metal hydroxide having
specific properties to address the poor curing problem. However,
25 Patent Literature 1 does not cover other inorganic fillers.
Patent Literature 2 to 4 teach technigues for dehydrating polyols
(Patent Literature 2: dehydrating agent; Patent Literature 3 and
4: pressure reduction with heating). However, Patent Literature 2
to 4 do not examine the aforementioned problem attributed to the
30 addition of an inorganic filler (in particular, metal hydroxides).
Moreover, none of Patent Literature 1 to 4 addresses their own
problem by suppressing foaming.
[00071
An object of the present invention is to provide a
35 polyurethane resin composition in which foaming is more
suppressed, despite the presence of an inorganic filler. further^,
an object of the invention is to provi.de a polyurethane resin
composition excellent in heat conductance and curing stability
i.., the curing rate is appropriate, foaming or poor curing is
5 unlikely to occur, and the curing rate is less changeable).
Solution to Problem
[0008]
The present inventor conducted extensive research to
10 achieve the objects, and found that they can be achieved by
producing a polyurethane resin composition using a polyol
composition for producing a polyurethane resin composition
(hereinafter, may sometimes be referred to as "polyol composition
of the present invention"), wherein the polyol composition
15 comprises a polyol, an inorganic filler, and a catalyst; and the
polyol composition has a moisture content adjusted to 0.2% or
less by a heating treatment and/or a depressurization treatment.
The inventors conducted further research based on these findings,
and completed the present invention. Specifically, the present
20 invention encompasses the following subject matter.
[0009] ~ Item 1. A polyol composition for producing a polyurethane resin
I
I
I composition, the polyol composition comprising a polyol, an
inorganic filler, and a polymerization catalyst, the polyol
25 composition having a moisture content adjusted to 0.2% or less by
a heating treatment and/or a depressurization treatment.
[OOlO]
Item 2. The polyol composition according to Item 1, wherein the
inorganic filler is a metal hydroxide.
30 [OOll]
Item 3. The polyol composition according to Item 1 or 2, wherei-n
the inorganic filler is present in an amount of 50 to 85% by mass
based on the polyol composition taken as 100% by mass.
[0012]
35 Item 4. The polyol composition according to any one of Items I to
3, wherein the polyol is a polybutadiene polyol and/or a castor
oil-based polyol.
[0013]
Item 5. The polyol composition according to any one of Items I to
5 4 obtained by a method comprising
step a of subjecting a composition comprising a polyol
and an inorganic filler to a heating treatment and/or a
depressurization treatment to reduce the moisture content of the
composition,
10 step b of adding a polymerization catalyst to the
composition that has undergone step a, and
step c of subjecting the composition that has undergone
step b to a heating treatment and/or a depressurization treatment
to reduce the moisture content of the composition.
15 [0014]
Item 6. The polyol composition according to Item 5, wherein
the heating treatment in step a is conducted at a
temperature of 40°C to 130°C,
the heating treatment in step c is conducted at a
20 temperature of 40'~ to 70°C, and
the depressurization treatment in steps a and c is
conducted at a pressure of 2.7 kPa or less.
[0015]
Item 7. The polyol composition according to any one ot Items 1 to
25 6 for use in the production of a polyurethane resin composition
for sealing an electrical or electronic component.
[00161
Item 8. A polyurethane resin composition comprising a
polyisocyanate and the polyol composition according to any one of
30 Items 1 to 7.
[0017]
Item 9. An electrical or electronic component resin-sealed with
the polyurethane resin composition according to Item 8.
[00181
35 Item 10. Use of a polyol composition for producing a polyurethane
resin composition, the polyol composition comprising a polyol, an
inorganic filler, and a polymerization catalyst, the polyol
composition having a moisture content adjusted to 0.2% or less by
a heating treatment and/or a depressurization treatment.
5 [0019]
Item 11. The use according to Item 10, for producing a
polyurethane resin composition for sealing an electrical or
electronic component.
[0020]
10 Item 12. A method for producing the polyol composition according
to any one of Items 1 to 4, the method comprising
sLep a of subjecting a composition comprising a polyol
and an inorganic filler to a heating treatment and/or a
depressurization treatment to reduce the moisture content of the
15 composition,
step b of adding a polymerization catalyst to the
composition that has undergone step a, and
step c of subjecting the composition that has undergone
step b to a heating treatment and/or a depressurization treatment
20 to reduce the moisture content of the composition.
[OO21]
Item 13. The method according' to Item 12, wherein
the heating treatment in step a is conducted at a
temperature of 40°C to 130°C,
2 5 the heating treatment in step c is conducted at a
temperature of 40°C to 70°C, and
the depressurization treatment in steps a and c is
conducted at a pressure of 2.7 kPa or less.
! 30 Advantageous Effects of Invention
4
i 9 [0022]
I
,I The use of the polyol composition of the present
invention in the production of a polyurethane resin composition
can provide a polyurethane resin composition (hereinafter, may
35 sometimes be referred to as "polyurethane resin composition of
the present invention") in which foaming is more suppressed,
despite the presence of an inorganic filler, exhibiting excellent
heat conductance and curing stability. Because of these
characteristics, the polyurethane resin composition of the
5 present invention is particularly suitable for sealing electrical
or electronic components, which are required to have
waterproofing properties or thermal radiation properties.
Description of Embodiments
10 LOO231
The term "comprising" as used herein encompasses the
terms "including," "containing," "consisting essentially of," and
"consisting of ." The term "hydrogenated" indicates "hydrogen
adduct. "
15 LOO241
1. Polyol Composition
The polyol composition of the present invention is a
polyol composition for producing a polyurethane resin composition,
and comprises a polyol, an inorganic filler, and a catalyst, with
20 the moisture content of the polyol composition being adjusted to
0.2% or less by a heating treatment and/or a depressurization
treatment. The following describes the polyol composition.
The polyol is not particularly limited as long as the
25 polyol has two or more hydroxyl groups, and various polyols used
for polyurethane resin compositions can be used. Examples of
polyols include ethylene glycol, 1,3-propanediol, 1,2-
propanediol, 2-methyl-l,3-propanediol, 1,4-butanediol, 1,3-
butanediol, 1,4-pentanediol, 1,s-pentanediol, 1,6-hexanediol,
30 1,5-hexanediol, 1, 2-hexanediol, 2,5-hexanediol, octanediol,
nonanediol, decanediol, diethylene glycol, triethylene glycol,
dipropylene glycol, cyclohexane diol, trimethylolpropane,
glycerol, 2-methylpropane-l,2,3-triol, 1,2,6-hexanetriol,
pentaerythritol, polylactone diol, polylactone triol, ester
35 glycol, polyester polyol, polyether polyol, polycarbonate polyol,
polybutadiene polyol., acrylic polyol, silicone polyol, fluorine
polyol, polytetramethylene glycol, polypropylene glycol,
polyethylene glycol, polycaprolactone polyol, castor oil-based
polyol, and dimer acid-based polyol. Of these, castor oil-based
5 polyols and/or polybutadiene polyol are preferably used.
LOO261
The castor oil-based polyols are not particularly
limited, and examples include castor oil and castor oil
derivatives.
10 LO0271
The castor oil derivatives are not particularly limited,
and examples include castor oil fatty acids; hydrogenated castor
oils obtained by adding hydrogen to castor oil or a castor oil
fatty acid; transesterification products of castor oil with other
15 oil; reaction products of castor oil with a polyhydric alcohol;
esterification reaction products of a castor oil fatty acid with
a polyhydric alcohol; and products obtained by addition
polymerization of these with an alkylene oxide. Of these castor
oil-based polyols, castor oil is preferably used.
20 [00281
The castor oil-based polyols have a molecular weight of
typically 100 to 4000, and preferably 300 to 2,500.
[0029]
The castor oil-based polyols have a hydroxyl group
25 content of typically 30 to 500 mg KOH/g, and preferably 100 to
200 mg KOH/g in hydroxy value.
[00301
Examples of comercially available products for use as
a castor oil-based polyol include products produced by Itoh Oil
30 Chemicals Co., Ltd. such as URIC H-30 (hydroxy value: 160, number
of functional groups: 3), URIC H-57 (hydroxy value: 100, number
of functional groups: 3), and URIC H-52 (hydroxy value: 200,
number of functional groups: 3).
[00311
3 5 The polybutadlene polyols are not particularly limited
as 1.ong as the polybutadiene polyols have a polybutadiene
structure with two hydroxyl groups in the molecule. Of these,
those having a hydroxyl group at each end of the linear
polybutadiene structure are preferable. Examples of polybutadiene
5 polyols include poly(l,4-butanediene)polyol, poly(1,2-
butadiene)polyol, and poly(l,2-/1,4-butadiene)polyol. Examples of
poly(l,2-/1,4-butadiene)polyol include a polyol having
polybutadiene repeating units containing 60 to 90 mol% of
butadiene joined together by 1,4-linakge, and 10 to 40 mol% of
10 butadiene joined together by 1,2-linkage, wherein the number of
the repeating units is 10 to 14, with one hydroxyl group at both
terminal ends of the polyol. More specifically, the polybutadiene
polyols may have a polybutadiene structure in which 1,3-butadiene
is trans- and 1,4-linked, a polybutadiene structure in which 1,3-
15 butadiene is cis- and l,4-linked, or a polybutadiene structure in
which 1,3-butadiene is 1,2-linked. Additionally, the
polybutadiene polyols may have a polybu-tadiene structure in which
these linkages are mixed.
[0032]
20 The polybutadiene polyols have a molecular weight of
preferably 800 to 4,800, and more preferably 1,200 to 3,000.
[0033]
The polybutadiene polypls may be hydrogenated
polybutadiene polyols, and examples of hydrogenated polybutadiene
25 polyols include those disclosed in JPH02-298574A. The
hydrogenated polybutadiene polyols are obtained through hydrogen
addition to the polybutadiene polyols stated above.
[00341
The polybutadiene polyols have an average hydroxy value
30 determined in accordance with JIS K1557-1 of preferably 20 to 250
mg KOH/g, and more preferabl~y 50 to 120 mg KOH/g.
[0035]
The polybutadiene polyols (A2) have a number average
molecular weight of preferably 500 to 5,000, and more preferably
35 1,000 to 3,500.
[0036]
The number average molecular weight can be measured by
gel permeation chromatography (GPC) (polystyrene conversion).
Specifically, the number average molecular weight by GPC can be
5 determined by measurement using Shodex GPC System-21 (produced by
Showa Denko K.K.) as a measuring apparatus, Shodex LF-804/KF-
803/KF-804 (produced by Showa Denko K.K.) as a column, and NMP as
a mobile phase at a column temperature of 40°C with the
calibration curve of standard polystyrene.
10 [00371
Examples of commercially available products for use as
a non-hydrogenaLed polybutadiene polyol include polybutadiene
diols largely containing l,4-linked repeating units (e.g., Poly
bd R-15HT (trademark) and Poly bd R-45HT (trademark) (both
15 produced by Idemitsu Kosan Co., Ltd.) ) , and poly(l,2-
butadiene)glycols largely containing 1,2-linked repeating units
(e.g., G-1000, G-2000, and G-3000 (all produced by Nippon Soda
Co., Ltd.)). Examples of commercially available products for use
as a hydrogenated polybutadiene diol include hydrogenated
20 polybutadiene diols largely containing 1,4-linked repeating units
(e.g., Polytail H and Polytail HA (both produced by Mitsubishi
Chemical Corporation) ) , and hydrogenated polybutadiene diols
largely containing 1,2-linked reneating units (e.g., GI-1000, GI-
2000, and GI-3000 (trade names; all produced by Nippori Soda Co.,
25 Ltd.)). Of these commercially available products, R-15HT and R-
45HT are preferably used.
[00381
The polyols may be used singly, or in a combination of
two or more.
30 [00391
The polyol content is not particularly limited, but is
preferably 0.5 to 30% by mass, and more preferably 1 to 25% by
mass based on the polyol composition of the present invention
taken as 100% by mass.
35 [00401
The inorganic filler is not particularly limited, and
various inorganic fillers used for polyurethane resin
compositions can be used. Examples of inorganic fillers include
aluminium hydroxide, alumina, aluminium nitride, boron nitride,
5 magnesium hydroxide, magnesium oxide, and zeolite. Of these,
metal hydroxides are preferable because of their excellent heat
conductance and flame retardancy, as well as suitability for
sealing electrical or electronic components. Of metal hydroxides,
aluminium hydroxide and magnesium hydroxide are preferable, and
10 aluminium hydroxide is more preferable.
[00411
The inorganic fillers may have either a spherical shape
or an irregular shape.
LO0421
15 The inorganic fillers may be used singly, or in a
combination of two or more.
[0043]
The inorganic filler content is preferably 50 to 85% by
mass, more preferably 55 to 85% by mass, still more preferably 60
20 to 80% by mass, and still yet more preferably 65 to 75% by mass
based on the polyol composition of the present invention taken as
100% by mass, from the standpoint of the heat conductance and
ease in processing of the ultimately obtained polyurethane resin
composition.
25 [0044]
The polymerization catalyst is not particularly limited,
and various polymerization catalysts used for polyurethane resin
compositions can be used. Examples of polymerization catalysts
include metal catalysts, such as organotin catalysts, organolead
30 catalysts, and organobismuth catalysts; and amine catalysts.
Examples of organotin catalysts include dioctyltin dilaurate,
dibutyltin diacetate, dibutyltin dilaurate, and dioctyltin
diacetate. Examples of organolead catalysts include lead octylate,
lead octenoate, and lead naphthenate. Examples of organobismuth
35 catalysts include bismuth octylate and bismuth neodecanoate.
Examples of amine catalysts include diethylenetriamine,
triethylamine, N,N-dimethylcyclohexylarnine, N,N,N',N1-tetramethyl
ethylene diamine, N,N,Nf ,Nr'N"-pentamethyl diethylenetriamine,
trimethylene diamine, dimethylaminoethanol, and bis(2-
5 dimethy1aminoethyl)ether. Additionally, organic metal compounds,
metal complex compounds, or the like may be used as a
polymerization catalyst.
[0045]
The polymerization catalysts may be used singly, or in
10 a combination of two or more.
[00461
The polymerization catalyst content is preferably
0.00001 to 10% by mass, and more preferably 0.0001 to 5% by mass
based on the polyol composition of the present invention taken as
15 100% by mass.
[0047]
The polyol composition of the present invention may
optionally contain a plasticizer.
[0048]
20 The plasticizer is not particularly limited, and
various plasticizers used for polyurethane resin compositions can
be used. Examples of plasticizers include phthalate esters, such
as dioctyl phthalate, diisononyl,phthalate, and diundecyl
phthalate; adipate esters, such as dioctyl adipate and diisononyl
25 adipate; castor oil-based esters, such as methyl acetyl
ricinoleate, butyl acetyl ricinoleate, acetylricinoleic
triglyceride, and acetylpolyricinoleic triglyceride; trimellitic
acid esters, such as trioctyl trimellitate and triisononyl
trimellitate; and pyromellitic acid esters, such as tetraoctyl
30 pyromellitate and tetraisononyl pyromellitate. Of these,
diisononyl phthalate is preferable.
[0049]
The plasticizers can be used singly, or in a
combination of two or more.
35 [00501
The plasticizer content is preferably 0.01 to 30% by
mass, and more preferably 1 to 20% by mass, based on the polyol
composition of the present invention taken as 100% by mass.
Setting the plasticizer content within these ranges can reduce
5 the viscosity of the mixture in the production of a polyurethane
resin composition without greatly decreasing the heat resistance
of the polyurethane resin composition.
[00511
The polyurethane resin composition of the present
10 invention may optionally contain additives, such as tackifiers,
curing accelerators, colorants, chain extenders, crossl~inkers,
fillers, pigments, bulking agents, flame retardants,
urethanization catalysts, ultraviolet ray absorbents,
antioxidants, moisture absorbents, antifoaming agents, fungicides,
15 and silane coupling agents.
[00521
The amount of these components for use can be suitably
determined, depending on the intended use, so that the desired
characteristics of the ultimately obtained polyurethane resin
20 composition are not impaired.
[0053]
The polyol composition of the present invention is
adjusted such that the polyol composition has a moisture content
of 0.2% or less by a heating treatment and/or a depressurization
25 treatment. Because of this adjustment, foaming of the ultimately
obtained polyurethane resin composition can be suppressed.
LO0541
The method for measuring the moisture content is not
particularly limited. Examples include the volumetric method and
30 the coulometric method. Of these, the volumetric method is
preferable. The measuring apparatus is also not particularly
limited; however, a Karl Fischer moisture meter is preferable.
[OO55]
The lower limit of the moisture content is not
35 particularly limited; however, it can be 0.01%, for example.
[0056]
The method of the heating treatment and/or
depressurization treatment is not particularly limited as long as
the moisture content can be adjusted to 0.2% or less. Examples
5 include a method comprising the following steps a to c.
[0057]
Step a: subjecting a composition comprising a polyol and an
inorganic filler to a heating treatment and/or a depressurization
treatment to reduce the moisture content of the composition
10 Step b: adding a polymerization catalyst to the composition that
has undergone step a
Step c: subjecting the composition that has undergone step b to a
heating treatment and/or a depressurization treatment to reduce
the moisture content of the composition
15 [0058]
In step a, the "composition comprising a polyol and an
inorganic filler" may optionally contain other components, such
as a plasticizer and additives, as long as the composition does
not contain a polymerization catalyst.
20 [00591
The temperature for the heating treatment in step a is
preferably 40°C to 130°c, more preferably 70 to 130°c, and still
more preferably 90 to 130°C from.the standpoint of the effect of
the present invention. Setting the temperature within these
25 ranges can suppress the volatilization of the plasticizer, while
removing the moisture adsorbed to the inorganic filler in a short
period of time. The pressure for the depressurization treatment
in step a is preferably 2.7 kPa or less, more preferably 2.0 kPa
or less, and still more preferably 1.5 kPa or less from the
30 standpoint of the effect of the present invention. Setting the
pressure within these ranges can remove moisture and bubbles more
efficiently, thus decreasing foaming at the time of curing and
shortening the defoaming time before use. It is preferable to
simultaneously conduct the heating treatment and the
35 depressurization treatment in step a.
[0060]
The time period of the heating treatment and/or
depressurization treatment in step a is, for example, about 0.25
to 4 hours, preferably about 0.5 to 2 hours, and more preferably
about 0.75 to 1.5 hours.
[0061]
In step b, not only the polymerization catalyst, but
also other components, such as a plasticizer and additives, can
optionally be added.
[0062]
The temperature for the heating treatment in step c is
preferably 40'~ to 70°c, and more preferably 50 to 70"~,fr om the
standpoint of the effect of the present invention. Setting the
temperature within these ranges can suppress the volatilization
of the catalyst while removing the moisture in a short period of
time. The pressure for the depressurization treatment in step c
is preferably 2.7 kPa or less, more preferably 2.0 kPa or less,
and still more preferably 1.5 kPa or less. It is preferable to
simultaneously conduct the heating treatment and the
depressurization treatment in step c.
[0063]
The time period of the heating treatment and/or a
depressurization treatment in step c is, for example, about 0.25
to 4 hours, arid preferably about 0.5 to 2 hours, and itlore
preferably about 0.75 to 1.5 hours.
[0064]
The polyol composition of the present invention is
used in the production of a polyurethane resin composition. The
foaming of the obtained polyurethane resin composition is more
suppressed, and the polyurethane resin composition exhibits
excellent heat conductance and curing stability; thus, the
polyurethane resin composition is particularly suitable for
sealing electrical or electronic components.
roo651
2. Polyurethane Resin Composit~ion -
The polyurethane resiin compositiorl of the present
inventi.on comprises a polyisocyanate and the polyol composition
of the present invention described above.
[00661
5 The polyisocyanate is not particularly limited as
long as the polyisocyanate is a compound containing two or more
isocyanate groups. Various polyisocyanates used for polyurethane
resin compositions can be used.
[00671
10 The polyisocyanate for use is preferably an
isocyanurate form. The use of an isocyanurate form provides a
polyurethane resin composition exhibiting excellent heat
resistance.
[0068]
15 Examples of such isocyanurate forms include
compounds obtained by converting aliphatic polyisocyanate
compounds, alicyclic polyisocyanate compounds, aromatic
polyisocyanate compounds, or aliphatic-aromatic polyisocyanate
compounds into their isocyanurate forms.
20 [00691
Examples of aliphatic polyisocyanate compounds
include tetramethylene diisocyanate, dodeca methylene
diisocyanate, hexamethylene diisqcyanate, 2,2,4-trimethyl
hexamethylene diisocyanate, 2,4,4-trimethyl hexamethylene
25 diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-
diisocyanate, and 3-methylpentane 1,5-diisocyanate.
[00701
Examples of alicyclic polyisocyanate compounds include
isophorone diisocyanate, hydrogenated xylylene diisocyanate,
30 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane
diisocyanate, methyl cyclohexylene diisocyanate, and 1,3-
bis(isocyanatemethyl)cyclohexane.
[00711
Examples of aromatic polyisocyanate compounds include
35 tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-
diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate
(MDI), 4,4'-dibenzyl diisocyanate, l,5-naphthylene diisocyanate,
xylylene diisocyanate, 1,3-phenylene diisocyanate, and 1,4-
phenylene diisocyanate.
5 to0721
Examples of aliphatic-aromatic polyisocyanate compounds
include dialkyl diphenylmethane diisocyanates, tetra-alkyl
diphenylmethane diisocyanates, and cx,a,a,a-tetramethyl xylylene
diisocyanate.
lo LOO731
As an isocyanurate form, isocyanurate forms of
aliphatic polyisocyanate compounds, alicyclic polyisocyanate
compounds, or aromatic polyisocyanate compounds are preferable.
Of these, isocyanurate forms of hexamethylene diisocyanate or
15 diphenylmethane diisocyanate are more preferable.
[0074]
Examples of polyisocyanates include, in addition to the
isocyanurate forms, the aforementioned aliphatic polyisocyanate
compounds, alicyclic polyisocyanate compounds, aromatic
20 polyisocyanate compounds, and aliphatic-aromatic polyisocyanate
compounds, as well as their allophanate-modified forms,
carbodiimide-modified forms, and adducts. Of these, isocyanurate
forms of aliphatic polyisocyanate compounds, alicyclic
polyisocyanate compounds, or aromatic polyisocyanate compounds
25 are preferable. In particular, isocyanurate forms of
hexamethylene diisocyanate or diphenylmethane diisocyanate are
preferable.
LO0751
Examples of commercially available products of
30 polyisocyanates include Millionate MTL (produced by Tosoh
Corporation), Duranate TLA-100 (HDI-based isocyanurate, produced
by Asahi Kasei Chemicals Corporation), and Coronate HX (HDI-based
isocyanurate, produced by Nippon Polyurethane Industry Co., Ltd.)
LO0761
3 5 The polyisocyanates can be used singly, or in a
combination of two or more.
LOO771
The polyisocyanate content in the polyurethane resin
composition of the present invention is not particularly limited,
5 but is preferably 1 to 50% by mass, and more preferably 5 to 40%
by mass based on the polyol taken as 100% by mass.
[0078]
In the polyurethane resin composition of the present
invention, the ratio of NCO in the polyisocyanate to OH in the
10 polyol is preferably 0.6 to 2.0, and more preferably 0.7 to 1.5.
[0079]
The method for producing the polyurethane resin
composition of the present invention is not particularly limited,
and the composition can be produced by a known method
15 conventionally used in the production of polyurethane resin
compositions.
[00801
Examples of such production methods include a method
comprising mixing the polyol composition of the present invention
20 (part B) with part A containing a polyisocyanate compound.
[008l]
Either part A or part B can comprise other components
such as a plasticizer and additiyes as long as part B comprises a
polyol, an inorganic filler, and a polymerization catalyst, and
25 part A comprises a polyisocyanate.
[0082]
The polyurethane resin composition may be in an uncured
liquid form, or in a cured form. Examples of methods for curing
polyurethane resin compositions include a method comprising
30 mixing part A with part B to react a polyol with a polyisocyanate,
and allowing the polyurethane resin composition to be cured over
time. When being cured, the composition may be heated. The
heating temperature is preferably about 40 to 120°C, and the
heating time is preferably about 0.5 to 24 hours.
35 [0083]
When the polyurethane resin composition of the
present invention is in an uncured liquid form, the viscosity
thereof is preferably 600 Pa's or less, and more preferably 400
Pa.s or less. In particular, the initial viscosity at the time of
5 mixing (the viscosity 2 minutes after the start of mixing of part
A and Part B) is preferably 100 Pa,s or less. Setting the
viscosity within these ranges can impart higher workability to
the polyurethane resin composition of the present invention. As
used herein, the viscosity of the uncured polyurethane resin
10 composition is the value determined by a Brookfield viscometer at
23°C.
[00841
The polyurethane resin composition of the present
invention can be used as a sealing material. Because of the well-
15 suppressed foaming, as well as excellent heat conductance and
curing stability, the polyurethane resin composition is
particularly suitable for sealing electrical or electronic
components. Examples of such electrical or electronic components
include transformers, such as transformer coils, choke coils, and
20 reactor coils, apparatus control boards, and various sensors. The
scope of the present invention also encompasses these electrical
or electronic components. The electrical or electronic components
of the present invention can be used in electric washing machines,
toilet seats, water heaters, water purifiers, baths, dishwashers,
25 electric power tools, automobiles, motorcycles, and the like.
Examples
[0085]
The following describes the present invention in detail
30 based on the Examples. However, the present invention is not
limited to these Examples.
[0086]
(1) Starting Materials
Polyisocyanatc: MDI-based isocyanate (trade name: Millionate MTL,
35 produced by Tosoh Corporation)
Plasticizer: diisononyl phthalate (trade name: DINP, produced by
J-PLUS Co., Ltd.)
Polyol 1: polybutadiene polyol having an average hydroxy value of
103 mg KOH/g (trade name: R-15HT, produced by Idemitsu Kosan Co.,
Ltd.)
Polyol 2: castor oil (trade name: castor oil, produced by Itoh
Oil Chemicals Co., Ltd.)
Polyol 3: polypropylene glycol (trade name: 0-1000, produced by
Mitsui Chemicals, Inc.)
Inorganic Filler: aluminium hydroxide (trade name: H-32 Higilite,
produced by Showa Denko K.K.)
Polymerization Catalyst: dibutyltin dilaurate (trade name: TN-12,
produced by Sakai Chemical Industry Co., Ltd.).
[00871
(2) Preparation of Part B
(2-1) Examples 1 to 5 and Comparative Examples 1 to 4
A polyol, a plasticizer, and an inorganic filler were
placed in a mixer (trade name: Awatori Rentaro, produced by
Thinky) and mixed at 2,000 rpm for 3 minutes. The obtained
composition was placed in a reaction furnace, and dehydrated at
100 to 120°C under 1.3 kPa or less over 1 hour. A polymerization
catalyst was then added thereto, and mixed. The mixture was
dehydrated at 55 to 65°C under 1-3 kPa or less over 1 hour,
thereby obtaining a composition as part B. The moisture content
of part B was measured with a Karl Fischer moisture meter (MKA-
610, produced by Kyoto Electronics Manufacturing Co., Ltd.),
using dehydration solvent CM (produced by Mitsubishi Chemical
Corporation, solvent) and Titrant SS-Z (produced by Mitsubishi
Chemical Corporation, titrant). Table 1 shows the measurement
results.
[0088]
(2-2) Examples 6 to - 8
The procedure for Examples 1 to 5 and Comparative Examples 1 to 4
was repeated except that a polynerization catalyst was added
simultaneously when a polyol, a plasticizer, and an inorganic
filler were placed in a mixer.
[0089]
Table 1
Note: The formulations 1% by m a s s ) are indicated on the basis of the total mass of all starting
materials (part A + part B) taken as 100%.
5
(3) Preparation of Polyurethane Resin Composition
Part A was added to part B in accordance with the
formulations shown in Table 1, and the mixture was mixed at 2,000
5 rpm for 60 seconds with a mixer (trade name: Awatori Rentaro,
produced by Thinky). The viscosity of the mixture at 2 3 " ~2
minutes after the start of mixing (initial viscosity at the time
of mixing) was measured with a Brookfield viscometer (Table 1)
The obtained mixture was a polyurethane resin composition. The
10 number of equivalents of isocyanate groups in part A per
equivalent of active hydrogen (OH) in part B (NCO/OH) was "1.00,"
as shown in Table 1.
(4) Preparation of Test Specimen
15 The prepared polyurethane resin composition was poured
into a mold (130x60~20m ). The composition was then heated at
8 0 " ~fo r 16 hours, and allowed to stand at room temperature for 1
day to be cured, thereby obtaining a test specimen.
100921
20 (5) Evaluation Test
In accordance with the following procedure and
evaluation criteria, the initial viscosity at the time of mixing,
foaming, hardness, heat conductiyity, and curability were
evaluated. Table 1 shows the evaluation results.
25 [00931
(5-1) Initial Viscosity at the Time of Mixing
0: less than 600 Pa.s
x: 600 Pa.s or more
(5-2) Foaming
3 0 The surface of the test specimen was visually observed
to confirm whether foaming occurred, and foaming was evaluated in
accordance with the following evaluation criteria.
0: no foaming is observed
A: one or two bubbles or cracks caused by foaming are observed
35 x : foaming is observed
(5-3) Hardness
The hardness of the test specimen was measured with an
Asker Type A rubber hardness tester, produced by Kobunshi Keiki
Co., Ltd., and the hardness was evaluated in accordance with the
5 following evaluation criteria.
0: the value is A 80 or less
A: the value is A 81 to A 90
x : the value is A 91 or more
(5-4) Heat Conductivity
10 The heat conductivity of the test specimen was measured
with a QTM-500, produced by Kyoto Electronics Manufacturing Co.,
Ltd., and the heat conductivity was evaluated in accordance with
the following evaluation criteria.
0: heat conductivity is 0.5 W/m.K or more
15 x: heat conductivity is less than 0.5 W/m.K
(5-5) Curability
The viscosity of the polyurethane resin compositions at
23'~ was measured with a BH-type rotational viscometer (produced
by Toki Sangyo Co., Ltd.). The time period over which the
20 viscosity becomes twice the initial viscosity at the time of
mixing was the assumed usable life. In Examples 6 to 8, an
increase in usable life of 10% or less is rated o, and 10% or
more is rated x, as compared with the usable life of the Examples
having the sane formulations as those of Examples 6 to 8 in which
25 part B was prepared following the procedure described in (2-1)
Examples 1 to 5 and Comparative Examples 1 to 4.
CLAIMS
[Claim 1]
A polyol composition for producing a polyurethane resin
composition, the polyol composition comprising a polyol, an
5 inorganic filler, and a polymerization catalyst, the polyol
composition having a moisture content adjusted to 0.2% or less by
a heating treatment and/or a depressurization treatment.
[Claim 2]
10 The polyol composition according to Claim 1, wherein
the inorganic filler is a metal hydroxide.
[Claim 3]
The polyol composition according to Claim 1 or 2,
wherein the inorganic filler is present in an amount of 50 to 85%
by mass based on the polyol composition taken as 100% by mass.
[Claim 4]
20 The polyol composition according to any one of Claims 1
to 3, wherein the polyol is a polybutadiene polyol and/or a
castor oil-based polyol.
[Claim 5]
25 The polyol composition according to any one of Claims 1
to 4 obtained by a method comprising
step a of subjecting a composition comprising a polyol
and an inorganic filler to a heating treatment and/or a
depressurization treatment to reduce the moisture content of the
30 composition,
step b of adding a polymerization catalyst to the
composition that has undergone step a, and
step c of subjecting the composition that has undergone
step b to a heating treatment and/or a depressurization treatment
35 to reduce the moisture cantent ot the composition.
[Claim 6]
The polyol composition according to Claim 5, wherein
the heating treatment in step a is conducted at a
5 temperature of 40°C to 130°C,
the heating treatment in step c is conducted at a
temperature of 40°C to 70°C, and
the depressurization treatment in steps a and c is
conducted at a pressure of 2.7 kPa or less.
10
[Claim 7]
The polyol composition according to any one of Claims 1
to 6 for use in the production of a polyurethane resin
composition for sealing an electrical or electronic component.
15
[Claim 8]
A polyurethane resin composition comprising a
polyisocyanate and the polyol composition according to any one of
Claims 1 to 7.
20
[Claim 9]
An electrical or electronic component resin-sealed with
the polyurethane resin compositi~n according to Claim 8.
[Claim 10]
Use of a polyol composition for producing a
polyurethane resin composition, the polyol composition comprising
a polyol, an inorganic filler, and a polymerization catalyst, the
polyol composition having a moisture content adjusted to 0.2% or
less by a heating treatment and/or a depressurization treatment.
[Claim 11]
The use according to Claim 10, for producing a
polyurethane resin composition for sealing an electrical or
electronic component.
[Claim 12]
A method for producing the polyol composition according
to any one of Claims 1 to 4, the method comprising
5 step a of subjecting a composition comprising a polyol
and an inorganic filler to a heating treatment and/or a
depressurization treatment to reduce the moisture content of the
composition,
step b of adding a polymerization catalyst to the
10 composition that has undergone step a, and
step c of subjecting the composition that has undergone
step b to a heating treatment and/or a depressurization treatment
to reduce the moisture content of the composition.
15 [Claim 13]
The method according to Claim 12, wherein
the heating treatment in step a is conducted at a
temperature of 40°C to 130°C,
the heating treatment in step c is conducted at a
20 temperature of 40°C to lO0C, and
the depressurization treatment in steps a and c is
conducted at a pressure of 2.7 kPa or less.