U.S. patent application number 10/787781 was filed with the patent office on 2004-08-26 for polyphenol resin, method for producing the same, epoxy resin composition and use thereof.
Invention is credited to Akatsuka, Yasumasa, Asano, Toyofumi, Imaizumi, Masahiro, Oshimi, Katsuhiko, Tomida, Syouichi.
Application Number | 20040166326 10/787781 |
Document ID | / |
Family ID | 26601592 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040166326 |
Kind Code |
A1 |
Akatsuka, Yasumasa ; et
al. |
August 26, 2004 |
Polyphenol resin, method for producing the same, epoxy resin
composition and use thereof
Abstract
An object of the present invention is to provide an epoxy resin
composition which has high flexibility, can be molded to a thin
membrane, and can become a noninflammable cured product. The
present invention comprises a polyphenol compound obtained by
reacting to condense phenol with bischloromethyl biphenyl or
bismethoxymethyl biphenyl, removing unreacted phenol and then
reacting with BCMB again, wherein the polyphenol compound has a
weight-average molecular weight of 3,000 or more as determined by
GPC, and using the polyphenol compound as an agent for curing an
epoxy resin.
Inventors: |
Akatsuka, Yasumasa;
(Saitama, JP) ; Asano, Toyofumi; (Saitama, JP)
; Imaizumi, Masahiro; (Tokyo, JP) ; Oshimi,
Katsuhiko; (Saitama, JP) ; Tomida, Syouichi;
(Tokyo, JP) |
Correspondence
Address: |
Kevin S. Lemack
Nields & Lemack
Suite 7
176 E. Main Street
Westboro
MA
01581
US
|
Family ID: |
26601592 |
Appl. No.: |
10/787781 |
Filed: |
February 26, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10787781 |
Feb 26, 2004 |
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10148701 |
May 31, 2002 |
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6723801 |
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10148701 |
May 31, 2002 |
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PCT/JP01/08693 |
Oct 3, 2001 |
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Current U.S.
Class: |
428/413 ;
257/E23.007 |
Current CPC
Class: |
C08L 63/00 20130101;
H01L 2924/0002 20130101; H01L 23/145 20130101; Y10T 428/31511
20150401; C08G 61/02 20130101; C08L 63/00 20130101; C08L 2666/22
20130101; H01L 2924/0002 20130101; H01L 2924/00 20130101 |
Class at
Publication: |
428/413 |
International
Class: |
B32B 027/38 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 5, 2000 |
JP |
2000-305854 |
Dec 12, 2000 |
JP |
2000-377920 |
Claims
1. A polyphenol resin represented by formula (1): 9wherein, n is an
average degree of polymerization calculated from the average
molecular weight, and having a weight-average molecular weight of
3,000 or more as determined by gel permeation chromatography (GPC,
hereinafter same).
2. An epoxy resin composition comprising (a) an epoxy resin having
at least two epoxy groups in the molecule and (b) the polyphenol
resin according to claim 1.
3. The epoxy resin composition according to claim 2, wherein said
epoxy resin is represented by formula (a): 10wherein, m is an
average degree of polymerization and a positive number.
4. The epoxy resin composition according to claim 2 or 3 further
comprising a curing accelerator.
5. A varnish comprising the polyphenol resin according to claim 1
and a solvent.
6. The varnish comprising the epoxy resin composition according to
any one of claims 2-4 containing a solvent.
7. A sheet comprising a layer formed by drying the varnish
according to claim 5 or 6 on the surface of a flat supporting
substrate.
8. The sheet according to claim 7, wherein said flat supporting
substrate is a polyimide film.
9. The sheet according to claim 7, wherein said flat supporting
substrate is a metallic foil.
10. The sheet according to claim 7, wherein said flat supporting
substrate is a release film.
11. A cured product obtained by curing the epoxy resin composition
according to any one of claims 2-4.
12. A curing agent for an epoxy resin comprising the polyphenol
resin according to claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to a polyphenol resin which
can provide an excellently noninflammable cured product and has
flexibility enough to form a film; an epoxy resin; and the cured
product, though it does not contain a halogenide flame-retardant or
an antimony compound.
BACKGROUND ART
[0002] An epoxy resin can be cured by various curing agents to
provide a cured product and it is generally excellent in mechanical
properties, water proofing, chemicals resistance, heat resistance
and electric properties. Therefore it has been widely utilized in
the fields of adhesive, paint, laminate, molding material and
casting material for example. The most popular epoxy resin which
has been used includes a bisphenol A type epoxy resin. Other,
tetrabromobisphenol A and the epoxylated product thereof, or the
compound produced by reacting a bisphenol A type epoxy resin with
tetrabromobisphenol A are generally known as a flame-retardant. As
a curing agent for an epoxy resin, an acid anhydride or an amine
compound is known, but a phenol novolac has been more often used in
the field of electric and electronic parts because of the high
reliability.
[0003] However, the above bromine-containing compound, if burned to
waste, is liable to generate a substance to cause environmental
pollution, though it is excellent in non-inflammability. An
antimony compound used for the non-inflammable auxiliary agent also
is concerned to have the toxicity.
[0004] Under this circumstance, recent increasing of consideration
to environmental conservation demands to develop a halogen-free and
antimony-free epoxy resin composition. On the other hand, an epoxy
resin cured by a phenol novolac gives a cured product which is too
tough and lacking in flexibility though it has excellent
creditability. The recently developed electric/electronic parts do
not take the conventional shape of a large package or a substrate
made of glass fiber as the base material, but takes a molded shape
of sheet obtained by coating a rasin in the form of varnish on a
polyimide or PET (polyethylene glycol terephthalate) film or on a
metallic foil and then removing the solvent. Therefore, it needs to
use the resin having sufficient flexibility.
DISCLOSURE OF THE INVENTION
[0005] In view of these circumstances, the present inventors have
studied diligently to find out an epoxy resin composition that can
provide an excellently non-inflammable cured product and can be
molded to a shape of sheet without losing the flexibility. As the
result, the present invention has been completed.
[0006] Namely the present invention is as follows:
[0007] (1) A polyphenol resin represented by formula (1): 1
[0008] wherein, n is an average degree of polymerization as
specified by the average molecular weight,
[0009] and having a weight-average molecular weight of 3,000 or
more as determined by gel permeation chromatography (GPC,
hereinafter same).
[0010] (2) A method for producing a polyphenol resin having a
weight-average molecular weight of 3,000 or more as determined by
GPC, comprising reacting to condense a polyphenol compound
represented by formula (1'): 2
[0011] wherein, n' is an average degree of polymerization as
specified
[0012] by the average molecular weight,
[0013] and having a weight-average molecular weight of 1,500 or
less as determined by GPC
[0014] with a biphenyl compound represented by formula (2): 3
[0015] wherein, X is a halogen, a C1-3 alkoxy group or hydroxyl
group, in an amount of 0.01 mol or more and less than 0.5 mol
relative to 1 equivalent of the phenolic hydroxyl group of the
polyphenol compound.
[0016] (3) An epoxy resin composition comprising (a) an epoxy resin
having at least two epoxy groups in the molecule and (b) the
polyphenol resin according to (1) mentioned above.
[0017] (4) The epoxy resin composition according to the above term
(3) mentioned above, wherein the epoxy resin is represented by
formula (a): 4
[0018] wherein, m is an average degree of polymerization and a
positive number.
[0019] (5) The epoxy resin composition according to the above term
(3) or (4) further comprising a curing accelerator.
[0020] (6) A varnish comprising the polyphenol resin according to
the above term (1) and a solvent.
[0021] (7) The varnish comprising the epoxy resin composition
according to any one of the above terms (3)-(5) containing a
solvent.
[0022] (8) A sheet comprising a layer formed by drying the varnish
according to the above term (6) or (7) on the surface of a flat
supporting substrate.
[0023] (9) The sheet according to the above term (8), wherein the
flat supporting substrate is a polyimide film.
[0024] (10) The sheet according to the above term (8), wherein the
flat supporting substrate is a metallic foil.
[0025] (11) The sheet according to the above term (8), wherein the
flat supporting substrate is a release film.
[0026] (12) A cured product obtained by curing the epoxy resin
composition according to any one of the above terms (3)-(5).
[0027] (13) A curing agent for an epoxy resin comprising the
polyphenol resin according to the above term (1).
BEST MODE FOR CARRYING OUT THE INVENTION
[0028] The present invention will be described in details
below.
[0029] In the below description, "part(s)" and "%" are "part(s) by
mass" and "% by mass" respectively, unless otherwise stated.
[0030] In the present invention, a halogen includes chlorine,
bromine and iodine; and a C1-3 alkoxy group includes methoxy group,
ethoxy group, n-propoxy group and i-propoxy group. In the formula
(2), the substituent XCH.sub.2--on each phenyl group substitutes at
any position of the positions 2, 3, and 4 or the positions 2', 3'
and 4'. In the formula (1), the bridging group (--CH.sub.2--)
corresponding to this substituent is also same as mentioned
above.
[0031] The polyphenol resin of the present invention having a
structure represented by the formula (1) and having a
weight-average molecular weight of 3,000 or more as determined by
GPC can be obtained for example by reacting to condense a
polyphenol compound represented by the above formula (1') with a
biphenyl compound represented by the formula (2) in the absence or
presence of a solvent generally in amount of 0.01 mol or more and
less than 0.5 mol, preferably 0.01-0.45 mol, and more preferably
0.05-0.4 mol relative to 1 equivalent of phenolic hydroxyl group of
the polyphenol compound.
[0032] In the condensation reaction, an acid catalyst may be used
if necessary. An acid catalyst, if the X is a halogen in the
biphenyl compound of the formula (2), is not necessary, but if the
X is an alkoxy group or hydroxyl group, it is necessary.
[0033] The polyphenol resin of the present invention may be
obtained by synthesizing a polyphenol compound represented by the
formula (1') by a method as described later (the first condensation
reaction) and then without isolation of the polyphenol compound
reacting to condense the polyphenol compound with a biphenyl
compound of the formula (2) (the second condensation reaction).
[0034] The biphenyl compound of the formula (2) includes 2,2'-,
3,3'- or 4,4'-bismethoxymethyl biphenyl, 2,2'-, 3,3'- or
4,4'-bisethoxymethyl biphenyl, 2,2'-, 3,3'- or
4,4'-bispropoxymethyl biphenyl, 2,2'-, 3,3'- or
4,4'-bischloromethyl biphenyl, 2,2'-, 3,3'- or 4,4'-bisbromomethyl
biphenyl, and 2,2'-, 3,3'- or 4,4'-bihydroxymethyl biphenyl.
[0035] The preferable compound of the formula (2) includes a
compound where X is a halogen, preferably chlorine or an alkoxy
group, preferably methoxy group. For a compound of the formula (2),
a mixture of 2,2' product, 3,3'product, 4,4' product and the others
is available on the market. A mixture containing 4,4'product as the
main component is preferable.
[0036] The preferable biphenyl compound represented by the formula
(2) to use in the condensation reaction of the present invention
includes a compound where X is a halogen, preferably chlorine.
[0037] The biphenyl compound of the above formula (2) in the
condensation reaction of the present invention is used generally in
an amount of 0.01 mol or more and less than 0.5 mol, preferably
0.01-0.45 mol, and more preferably 0.05-0.4 mol relative to 1
equivalent of phenolic hydroxyl group of the compound of the
formula (1').
[0038] The condensation reaction of the present invention can be
carried out in the absence or presence of a solvent, but it is
preferable to use the solvent in the reaction because the viscosity
of the reaction solution increases with increasing the molecular
weight. Any solvent may be used if it has no bad influence on the
reaction. The preferable solvent includes a lower alkylene glycol
mono- or di-lower alkyl ether. The preferable carbon number in the
lower alkylene and the lower alkyl is 1-5. The preferable solvent
includes propylene glycol monomethyl ether, propylene glycol
monobutyl ether, propylene glycol dimethyl ether, methyl cellosolve
and ethyl cellosolve. The amount of the solvent to use is generally
5-500%, preferably 10-400% relative to the mass of a reaction
product.
[0039] If the compound where X is an alkoxy group, preferably
methoxy group is used as a biphenyl compound represented by the
formula (2), it is preferable to use an acid catalyst such as
hydrochloric acid, sulfuric acid and para-toluene sulfonic acid in
the condensation reaction of the present invention. Of these acid
catalysts, para-toluene sulfonic acid is the most preferable.
[0040] The reaction is made until a biphenyl compound represented
by the formula (2) disappears completely. The reaction temperature
is generally 60-140.degree. C. The reaction time is generally 1-20
hours.
[0041] A polyphenol compound represented by the formula (1') can be
obtained by reacting to condense a biphenyl compound represented by
the formula (2) with a phenol at such a rate that amount of the
phenol is generally 1.5-10 mol, preferably 2-8 mol relative to 1
mol of the biphenyl compound and then removing an unreacted
phenol.
[0042] In the synthesis of a polyphenol compound of the formula
(1') (the above first condensation reaction), an acid catalyst is
used if necessary. The acid catalyst, if X is a halogen atom in the
biphenyl compound of the formula (2), is not necessary, but if X is
an alkoxy group or hydroxyl group, the acid catalyst is used. The
preferable biphenyl compound of the formula (2) used in this
reaction includes a compound where X is an alkoxy group, preferably
methoxy group. The acid catalyst in the first condensation reaction
includes hydrochloric acid, sulfuric acid and para-toluene sulfonic
acid. Para-toluene sulfonic acid is especially preferable. An
amount of the acid catalyst is 0.001-0.1 parts, preferably
0.005-0.05 parts relative to 1 mol of a compound represented by the
formula (2). The first condensation reaction can be carried out in
the absence or presence of a solvent. When the solvent is used, any
solvent may be used if it has no bad influence on the reaction. The
preferable solvent includes a lower alcohol such as methanol,
ethanol and isopropanol and a lower alkyl lower alkyl ketone such
as methyl ethyl ketone and methyl isobutyl ketone. The solvent is
used generally in an amount of 10-300%, preferably 20-250% relative
to the total mass of a compound represented by the formula (2) and
the phenol. The reaction is made until the compound represented by
the formula (2) disappears completely. The reaction temperature is
generally 40-150.degree. C. The reaction time is generally 1-10
hours. After the condensation reaction terminates, the acid
catalyst is removed by neutralizing and washing, and then the
solvent and the unreacted phenol are removed by heating under
reduced pressure. The condensate thus obtained is represented by
the formula (1'), and has a structure that a biphenyl molecule is
bonded with a phenol molecule through the methylene bond. The
weight-average molecular weight thereof is about 500-1,500. The
softening point is about 50-100.degree. C., though it cannot be
specified because it varies according to the average molecular
weight.
[0043] If a compound where X is a halogen in the formula (2) is
used in the condensation reaction of the present invention or in
the first condensation reaction, it is preferable that the hydrogen
halogenide generated as the side reaction product is removed from
the reaction system. The method is not limited to a particular one,
as long as it can remove the hydrogen halogenide from the system.
For example, nitrogen gas is blown into through the one side of a
reaction vessel while the hydrogen chloride gas generated as the
side reaction product is removed through another side by a tube and
then bubbled to trap into an aqueous alkaline solution such as an
aqueous sodium hydrogen solution.
[0044] The condensation reaction of the present invention is
preferably carried out in the presence of a solvent. Sometimes, a
couple of thousands ppm of hydrogen chloride which cannot be
removed even by the above removing method remain in the solvent.
The remaining hydrogen chloride is undesirable when the polyphenol
resin solution as obtained above is directly used for a varnish of
the present invention as described later. In such a case, the
hydrogen chloride is removed as follows. After the reaction
terminates, the solution is cooled down to 100' or less. Water is
added to the solution followed by stirring to make a suspension in
order to transfer the hydrogen chloride into water and heating to
distill the hydrogen chloride-containing water and the solvent
simultaneously by an azeotropic dehydration process. The distilled
solvent is then returned back to the system. The hydrogen chloride
dissolved in the solvent can be almost removed by repeating the
above method.
[0045] The condensation reaction of the present invention, if the X
is hydroxyl group or an alkoxy group, needs an acid catalyst. The
acid catalyst may be same kind and amount as in the first
condensation reaction. Water and the alcohol generated as the
reaction by-product are removed from the system by a fractionating
column.
[0046] After the reaction terminates, the by-product or the solvent
used can be removed to get a solid polyphenol resin. The polyphenol
resin of the present invention has a high molecular weight.
Therefore, no or a part of solvent may be removed from the resin so
that the resin have a suitable viscosity and have good workability
according to an using object.
[0047] The polyphenol resin represented by the formula (1) thus
obtained has generally an average degree of polymerization (n) of 4
or more, preferably 4-20, and more preferably 4.5-15. The average
degree of polymerization is a value calculated from the
number-average molecular weight as determined by GPC. The
weight-average molecular weight (GPC) is 3,000 or more and
preferably 3,000-20,000. The softening point is generally
110-150.degree. C. and, in the preferable embodiment, about
115-145.degree. C. The hydroxyl equivalent is 210-300 g/eq,
preferably 215-290 g/eq.
[0048] The polyphenol resin composition of the present invention
thus obtained can be used suitably as a curing agent for an epoxy
resin and a membrane-forming component of a varnish.
[0049] The epoxy resin composition of the present invention is
characterized by comprising a polyphenol resin composition of the
present invention and an epoxy resin having two or more epoxy
groups in the molecule, and can be obtained generally by mixing
homogeneously the above both and the other ingredients to add if
necessary.
[0050] The epoxy resin is not limited to a particular one, as long
as it has two or more epoxy groups in the molecule. It concretely
includes a novolac type epoxy resin or a triphenylmethane type
epoxy resin, a dicyclopentadiene phenol condensation type epoxy
resin, a xylylene structure-containing phenol novolac type epoxy
resin, a biphenyl structure--containing novolac type epoxy resin, a
bisphenol A type epoxy resin, a bisphenol F type epoxy resin and a
tetramethyl biphenol type epoxy resin, though not limited to these
epoxy resins. These epoxy resins may be used alone or in
combination of the two or more.
[0051] In these epoxy resins, it is preferable that a resin
represented by the following formula (a) 5
[0052] wherein m is an average value and is generally a positive
number of 1.0-5, preferably 1.1-4, is used because it can provide a
cured product having excellent heat resistance.
[0053] As a curing agent in the epoxy resin composition of the
present invention, other curing agents may be used in combination
with a polyphenol resin of the present invention. Any other curing
agent may be used as long as it can be used as an curing agent for
an epoxy resin. The other curing agents include diamino diphenyl
methane, diethylene triamine, triethylene tetramine, diamino
diphenyl sulfone, isophorone diamine, dicyan diamide, a polyamide
resin synthesized from linolenic acid dimer and ethylene diamine,
phthalic anhydride, trimellitic anhydride, pyromellitic anhydride,
maleic anhydride, tetrahydrophthalic anhydride,
methyltetrahydrophthalic anhydride, methylnadic anhydride,
hexahydrophthalic anhydride, methylhexahydrophthalic anhydride,
phenol novolac, triphenylmethane and these denatured products,
imidazole, BF.sub.3-amine complex, and a guanidine derivative,
though not limited to these substances. A polyphenol resin of the
present invention, if used in combination with these other curing
agents, is contained generally in rate of 0.2 equivalent weight or
more, preferably 0.3 equivalent rate or more in all the curing
agents.
[0054] The curing agent in an epoxy resin composition of the
present invention is used preferably in an amount of 0.7-1.2
equivalent relative to 1 equivalent of epoxy group of the epoxy
resin.
[0055] A curing accelerator may be used in combination with the
above curing agent in an epoxy resin composition of the present
invention. The curing accelerator includes, for example, an
imidazole such as 2-methylimidazole, 2-ethylimidazole, and
2-ethyl-4-methylimidazole; a tertiary amine such as
2-(dimethylaminomethyl)phenol, and 1,8-diaza-bicyclo(5,4,0)
undecene-7; a phosphine such as triphenylphosphine; and a metal
compound such as stannum octylate. The curing accelerator is used
if necessary in an amount of 0.1-5.0 parts relative to 100 parts of
an epoxy resin and may have been mixed as one component in the
epoxy resin composition of the present invention or may be mixed
when the epoxy resin is used.
[0056] An epoxy resin composition of the present invention may
contain an inorganic filler if necessary. The inorganic filler
includes, for example, silica, alumina and talc. The inorganic
filler to use has a share of 0-90% in the epoxy resin composition
of the present invention.
[0057] An epoxy resin composition of the present invention may
contain various ingredients including a silane coupling agent, a
releasing agent such as stearic acid, palmitic acid, zinc stearate
and calcium stearate and a pigment if necessary.
[0058] An epoxy resin composition of the present invention can be
obtained by mixing homogeneously the above components in their
respective rates and can be used in various fields as a
conventional epoxy resin composition has been used. A polyphenol
resin of the present invention, which has a structure of the
biphenyl group bonded with phenol through methylene group, has a
high refractive index. The epoxy resin composition of the present
invention, which contains the polyphenol resin, has also a high
refractive index and hence can be suitably used as an optical
material for optical lens, lens for spectacles, a substrate for
optical disc and plastic optical fiber. In this case, a biphenyl
structure-containing novolac type epoxy resin (for example,
NC-3000S or NC-3000S-H made by NIPPON KAYAKY), which has same
structure as a polyphenol resin of the present invention does, is
used as the epoxy resin component, resulting in an excellent
effect.
[0059] An epoxy resin composition of the present invention may
contain a solvent in some cases. The epoxy resin composition
containing the solvent can be infiltrated into a base material such
as glass fiber, carbon fiber, polyester fiber, polyamide fiber,
alumina fiber and paper, followed by heating to dry to get a
prepreg. The prepreg can then be pressed and molded under heating
to obtain the cured product of an epoxy resin composition of the
present invention. The content of solvent in the epoxy resin
composition is generally 10-70%, preferably 15-70% relative to the
total amount of the epoxy resin composition of the present
invention and the solvent. The epoxy resin composition containing
the solvent can be used as a varnish as described below. The
solvent includes toluene, xylene, acetone, methyl ethyl ketone and
methyl isobuthyl ketone, as will be shown in the below paragraph of
varnish.
[0060] As long as a varnish of the present invention comprises a
polyphenol resin of the present invention and a solvent, the other
components are not limited. Provided that the varnish of the
present invention is a liquid composition in which the polyphenol
resin, the solvent and if necessary additional optional components
are mixed homogeneously, a method for producing the liquid
composition is not limited to any particular one. For example, the
reaction solution as obtained in the process for producing the
polyphenol resin of the present invention, which contains the
polyphenol resin and the solvent, can be used directly as a varnish
of the present invention. One or more selected from the group
consisting of the other optional component, the polyphenol resin
and a solvent, if necessary, can be added to the reaction solution
to get a varnish of the present invention. Alternatively, the
reaction solution may be concentrated to make a concentrate, to
which the other optional component and/or the polyphenol resin are
added if necessary to get a varnish of the present invention. An
isolated polyphenol resin may be mixed homogeneously with the other
optional component if necessary in a solvent to get a varnish of
the present invention.
[0061] The optional component added into a varnish of the present
invention is not limited to any particular one as long as it does
not block the membrane formation or the adhesive property of a
polyphenol resin of the present invention. The preferable one,
however, includes a polymer, an epoxy compound and their
accompanying additive that are able to form a membrane together
with the polyphenol resin. The polymer is preferably soluble in a
solvent used in a varnish of the present invention. One of the
preferable varnishes includes a varnish containing the epoxy
compound. The varnish containing both an epoxy resin composition of
the present invention and a polyphenol resin of the present
invention is specifically preferable.
[0062] A solvent used in a varnish of the present invention
includes .gamma.-butyrolactones, an amide solvent such as N-methyl
pyrrolidone(NMP), N,N-dimethyl formamide(DMF), N,N-dimethyl
acetamide and N,N-dimethyl imidazolidinone; a solfone such as
tetramethylene sulfone; an ether solvent such as diethylene glycol
dimethyl ether, diethylene glycol diethyl ether, propylene glycol,
propylene glycol monomethyl ether, propylene glycol monomethyl
ether monoacetate, propylene glycol monobutyl ether, preferably a
lower alkylene glycol mono or di-lower alkyl ether; a ketone
solvent such as methyl ethyl ketone and methyl isobutyl ketone,
preferably a di-lower alkyl ketone where the two alkyl groups may
be same or not; and an aromatic solvent such as toluene and xylene.
The preferable solvent includes a lower alkylene glycol mono or
di-lower alkyl ether and the above di-lower alkyl ketone. These
solvents may be used alone or in combination of the two or
more.
[0063] The solid part in the varnish thus obtained is generally a
concentration of 10-90%, preferably 20-80%, more preferably 25-70%.
The remainder is the solvent.
[0064] The content of the polyphenol resin of the present invention
in the varnish is generally content of 10-60%, preferably 20-50%
relative to the total amount of the varnish. The content of the
epoxy resin is content of 10-40%, preferably 15-35%. The other
additive is content of 0-20%.
[0065] A sheet of the present invention can be obtained by coating
the above varnish on a base material, preferably on the surface of
a flat supporting substrate by a known coating method such as
gravure coating, screen process printing, metal masking and spin
coating followed by drying. The sheet thus obtained has a thickness
(a thickness after drying) of 5-300 .mu.m, preferably 5-200 .mu.m,
more preferably 10-160 .mu.m. The varnish may be coated on the one
side surface, the both side surfaces or the partial surface of a
flat supporting substrate if necessary. The coating method to use
is suitably chosen according to the kind, shape, scale of a base
material and the thickness of a membrane. The base material
includes a film made of polymer and/or copolymer such as polyamide,
polyamidimide, polyarylate, polyethylene terephthalate,
polybutylene terephthalate, poly(ether ether ketone),
poly(etherimide), poly(ether ketone), polyketone, polyethylene and
polypropylene; and a metal foil such as a copper foil. A film made
of polyimide or a metal foil is preferable.
[0066] The sheet having a membrane formed with the varnish of the
present invention thus obtained is useful as a substrate for
electric/electronic parts.
[0067] A sheet shape of adhesive agent can be produced by coating
the varnish of the present invention on a release film and then
heating to remove the solvent and to bring the resin into the B
stage. The sheet shape of adhesive agent thus obtained can be used
for the interlayer dielectric layer in a multiplayer board.
EXAMPLE
[0068] The present invention is described below in details by
examples and comparative examples. In the examples, the measurement
conditions of GPC are as follows:
[0069] Apparatus: Shodex SYSTEM-21
[0070] Column: KF-804L+KF-803L (.times.2 columns) connected
[0071] Eluate: THF(tetrahydrofurane); 1 ml/min., 40'
[0072] Detector: RI(RI-71S), UV(254 nm, UV-41)
[0073] Sample: about 0.4% THF solution (100 al inject)
[0074] Calibration curve: Shodex standard polystyrene used
Example 1
[0075] 121 parts of the compound (bismethoxymethyl biphenyl)
represented by the following formula (3): 6
[0076] and 188 parts of phenol were put in a flask equipped with a
thermometer, a cooler, a fractionating column and a stirrer in the
presence of purging nitrogen gas and were dissolved by raising the
temperature up to 130% under stirring. 0.5 parts of para-toluene
sulfonic acid was added, followed by reacting for 3 hours under the
removal of the arising methanol from the system through the
fractionating column. After the reaction terminated, 260 parts of
methyl isobutyl ketone was added. The mixture was washed thrice
with water. The oil layer was distilled by heating under reduced
pressure using evaporator to remove methyl isobutyl ketone and the
unreacted phenol, and 170 parts of the compound (n'=2.2, average)
(called Compound A) represented by the formula (1') was obtained.
Compound A thus obtained had a softening point of 6.degree. C., a
melt viscosity of 0.08 Pa.multidot.s at 150.degree. C., a hydroxyl
equivalent of 204 g/eq, and a weight-average molecular weight of
940 as determined by GPC.
[0077] 204 parts of Compound A, 50.1 parts of the compound
(bischlormethyl biphenyl) represented by the following formula (4):
7
[0078] and 24.0 parts of propylene glycol monobutyl ether were put
in a flask equipped with a thermometer, a fractionating column, a
stirrer and a cooler to the top end of which a silicone tube was
connected so that inside-arising hydrochloric acid gas is able to
expel from the system under purging nitrogen gas. Another open end
of the silicone tube was fixed to another vessel containing an
aqueous sodium hydroxide solution to immerse in. The solution was
heated up to 150.degree. C. under stirring to carry out the
dehydrochlorination reaction. Generated hydrochloric acid gas was
trapped in the aqueous sodium hydroxide solution. The reaction was
carried out for 6 hours followed by cooling the reaction system
down to 140.degree. C., adding further 72.0 parts of another
propylene glycol monobutyl ether and then cooling furthermore down
to 80.degree. C. 120 parts of 80.degree. C. hot water was added to
make a suspension, which was stirred for 30 minutes and heated to
distill water and propylene glycol monobutyl ether away from the
system with an azeotropic dehydration. Only the propylene glycol
monobutyl ether was returned back in the system by the
fractionating column. The procedure, starting with adding hot water
and ending with returning only propylene glycol monobutyl ether
back in the system by the fractionating column, was repeated
thrice. The solution was cooled to 70.degree. C., and 144 parts of
methyl ethyl ketone was added to obtain 480 parts of a 50% varnish
of the polyphenol resin of the present invention. The polyphenol
resin thus obtained had a weight-average molecular weight of 12,800
as determined by GPC, a hydroxyl equivalent of 248 g/eq and n in
the formula (1) was 7(averaged).
Example 2
[0079] 27 parts of the compound NC-3000P as an epoxy resin(made by
NIPPON KAYAKU KK, epoxy equivalent 270 g/eq, softening point
58.degree. C., n=2.5 (averaged)) represented by the formula (5):
8
[0080] , 73.8 parts of 50 wt % propylene glycol monomethyl
ether/methyl ethyl ketone solution (propylene glycol monomethyl
ether: methyl ethyl ketone=96:144) of the polyphenol resin obtained
in Example 1 as a curing agent, and 0.27 parts of triphenyl
phosphine as a curing accelerator were mixed and stirred for 3
hours at 100% to make a solution. The solution was cooled down to
room temperature to get a varnish of the present invention. The
varnish was coated on a polyimide film by an applicator so that a
membrane after drying could have a thickness of 25 .mu.m. The test
piece obtained was heated for 3 hours at 150% to get a cured
product. The cured product obtained on the polyimide had
satisfactory film-forming performance, because it was free from
cracking while the polyimide was rounded to bend. The cured product
was tested in respect to noninflammability according to UL94-VTM.
It was confirmed to clear VTM-0.
Example 3
[0081] The epoxy resin (EPPN-502H, made by NIPPON KAYAKU KK, epoxy
equivalent: 170 g/eq, softening point: 70.2.degree. C., m=1.9 in
the formula (1)) represented by the above formula (a), the 50%
solution of polyphenol resin obtained in Example 1 as a curing
agent, and triphenyl phosphine as a curing accelerator were mixed
at a mass ratio as shown in Table 1 and dissolved homogeneously to
make a varnish. The solution was cooled down to room temperature to
get a varnish of the present invention.
1 TABLE 1 Composition of mixture Example 1 EPPN-502H 100 50%
solution of polyphenol resin 291 triphenyl phosphine 1
[0082] The varnish thus obtained was coated on a polyimide film by
an applicator so that a membrane after drying could have a
thickness of 25 .mu.m. The test piece obtained was heated for 3
hours at 180.degree. C. to get a cured product. The cured product
thus obtained on the polyimide film had satisfactory film-forming
performance, because it was free from cracking while the polyimide
film was rounded to bend. The cured product was tested in respect
to noninflammability according to UL94-VTM. It was confirmed to
clear VTM-0.
[0083] The varnish was coated on a 30 .mu.m thick copper foil by an
applicator so that a membrane could have a thickness of 150 g m
after drying. The test piece thus obtained was heated for 3 hours
at 180% followed by dissolving the copper foil in an etching
solution to get a cured product. The cured product had a glass
transition point of 208.degree. C. as determined by DMA (Dynamic
viscoelasticity measurement apparatus).
INDUSTRIAL APPLICABILITY
[0084] A polyphenol resin of the present invention, if used as a
curing agent for an epoxy resin, can provide a cured product which
has high flexibility, can be molded to a thin membrane and has
excellent noninflammability, compared with a conventionally used
epoxy resin composition. An epoxy resin composition of the present
invention is very useful for the wide application to molding
material, casting material, laminating material, paint, adhesive
and resist.
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