U.S. patent application number 11/057182 was filed with the patent office on 2005-08-18 for novel cyanate ester compound, flame-retardant resin composition, and cured product thereof.
Invention is credited to Katagiri, Masayuki, Kita, Seiji, Ohno, Daisuke, Shima, Yoshikazu, Sugano, Yuuichi.
Application Number | 20050182203 11/057182 |
Document ID | / |
Family ID | 34709092 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050182203 |
Kind Code |
A1 |
Sugano, Yuuichi ; et
al. |
August 18, 2005 |
Novel cyanate ester compound, flame-retardant resin composition,
and cured product thereof
Abstract
A cyanate ester compound represented by the formula (1), 1
wherein Ar.sub.2 represents a phenylene group, a naphthylene group
or a biphenylene group, Ar.sub.1 represents a naphthylene group or
a biphenylene group when Ar.sub.2 is a phenylene group, or Ar.sub.1
represents a phenylene group, a naphthylene group or a biphenylene
group when Ar.sub.2 is a naphthylene group or a biphenylene group,
R.sub.x represents all substituents of Ar.sub.1 each R.sub.x is the
same or different and represents hydrogen, an alkyl group or an
aryl group, R.sub.y represents all substituents of Ar.sub.2, each
R.sub.y is the same or different and represents hydrogen, an alkyl
group or an aryl group, and n is an integer of 1 to 50.
Inventors: |
Sugano, Yuuichi;
(Niigata-shi, JP) ; Katagiri, Masayuki;
(Niigata-shi, JP) ; Ohno, Daisuke; (Tokyo, JP)
; Kita, Seiji; (Kurashiki-shi, JP) ; Shima,
Yoshikazu; (Niigata-shi, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
34709092 |
Appl. No.: |
11/057182 |
Filed: |
February 15, 2005 |
Current U.S.
Class: |
525/423 |
Current CPC
Class: |
C08K 5/29 20130101; H05K
3/386 20130101; C09D 5/18 20130101; H05K 1/0346 20130101; C08G
73/0655 20130101; Y10T 428/31699 20150401; G02F 1/1339 20130101;
C09K 21/14 20130101; C07C 261/02 20130101 |
Class at
Publication: |
525/423 |
International
Class: |
C08L 063/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2004 |
JP |
041055/2004 |
Claims
What is claimed is:
1. A cyanate ester compound represented by the formula (1),
13wherein Ar.sub.2 represents a phenylene group, a naphthylene
group or a biphenylene group, Ar.sub.1 represents a naphthylene
group or a biphenylene group when Ar.sub.2 is a phenylene group, or
Ar.sub.1 represents a phenylene group, a naphthylene group or a
biphenylene group when Ar.sub.2 is a naphthylene group or a
biphenylene group, R.sub.x represents all substituents of Ar.sub.1,
each R.sub.x is the same or different and represents hydrogen, an
alkyl group or an aryl group, R.sub.y represents all substituents
of Ar.sub.2, each R.sub.y is the same or different and represents
hydrogen, an alkyl group or an aryl group, and n is an integer of 1
to 50.
2. A cyanate ester compound according to claim 1, wherein the
compound of the formula (1) is a compound of the formula (2),
14wherein R.sub.1 to R.sub.4 are the same or different and
represent hydrogen or an alkyl group, n is an integer of 1 to 50,
and the position of each substituent of aromatic rings can be
arbitrarily selected.
3. A cyanate ester compound according to claim 1, wherein the
compound of the formula (1) is a compound of the formula (3),
15wherein R.sub.1 to R.sub.4 are the same or different and
represent hydrogen or an alkyl group, n is an integer of 1 to 50,
and the position of each substituent of aromatic rings can be
arbitrarily selected.
4. A cyanate ester compound according to claim 1, wherein the
compound of the formula (1) is a compound of the formula (4),
16wherein R.sub.1 and R.sub.2 are the same or different and
represent hydrogen or an alkyl group, n is an integer of 1 to 50,
and the position of each substituent of aromatic rings can be
arbitrarily selected.
5. A cyanate ester compound according to claim 2, wherein the
compound of the formula (2) is a compound of the formula (5),
17wherein n is an integer of 1 to 50.
6. A cyanate ester compound according to claim 3, wherein the
compound of the formula (3) is a compound of the formula (6).
18
7. A cyanate ester compound according to claim 4, wherein the
compound of the formula (4) is a compound of the formula (7),
19wherein n is an integer of 1 to 50.
8. A thermosetting resin composition containing the cyanate ester
compound recited in claim 1 and a curing agent.
9. A cured product obtained by curing the thermosetting resin
composition recited in claim 8.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a novel cyanate ester
compound, a thermosetting resin composition containing the above
compound and a cured product thereof. The cyanate ester compound of
the present invention can provide a polymer material excellent in
flame resistance, heat resistance and low dielectric
characteristics by polymerizing the cyanate ester compound itself
or copolymerizing the cyanate ester compound with another resin.
Such a thermosetting resin composition can be widely used for
applications such as an electrical insulating material, a resin for
a resist, a semiconductor-sealing resin, an adhesive for a printed
wiring board, a matrix resin for a laminate or a prepreg used for
electrical devices, a buildup laminate material, a resin for a
fiber-reinforced plastic, a sealing resin for a liquid crystal
display panel, a resin for a color filter of liquid crystal, a
coating composition, various coating agents and an adhesive.
PRIOR ARTS OF THE INVENTION
[0002] Cyanate ester resins generate a triazine ring by curing and
have been widely used as raw materials for a variety of functional
polymer materials such as structural composite materials,
adhesives, electrical insulating materials or electrical and
electric parts due to their high heat resistance and excellent
electric characteristics. However, in recent years, as higher
performances are required in their application fields, physical
properties required as a functional polymer material become severer
increasingly. As such physical properties, for example, there are
required flame resistance, heat resistance, low dielectric
constant, low dielectric loss tangent, weather resistance, chemical
resistance, low moisture absorptivity, high fracture toughness,
etc. So far, these required properties have not completely
satisfied.
[0003] In a printed wiring board material field, for example, as a
communication frequency and a clock frequency are increasing, a
material having a low dielectric constant and a low dielectric loss
tangent becomes required. For this reason, cyanate resins excellent
in dielectric characteristics come to be used. In this case, it is
necessary to impart flame resistance in view of safety from fire
and bromine compounds having high flame resistance are used. For
example, brominated bisphenol A (JP-B-4-24370), a glycidyl ether of
brominated phenol novolak (JP-A-2-286723), brominated maleimides
(JP-A-7-207022), halogen-containing monofunctional cyanates
(JP-A-6-122763) and an additive type bromine compound having no
reactivity with a cyanate ester compound (JP-A-2000-95938) are
known.
[0004] Such bromine compounds have high flame resistance, while
corrosive bromine and hydrogen bromide are separated therefrom by
thermal decomposition. Therefore, materials which do not contain a
bromine type flame retardant are desired.
[0005] Then, phosphorus-containing compounds, nitrogen-containing
compounds and sulfur-containing compounds have been studied as a
flame retardant instead of bromine. For example, triphenyl
phosphate, resorcinol bis(diphenylphosphate), etc., are studied as
a phosphorus compound which is often incorporated into an epoxy
resin. However, when such a compound is incorporated in a large
amount, heat resistance, moisture resistance, water absorptivity,
etc., decrease in many cases.
[0006] For overcoming the above problem, a method in which a
phosphorus compound having a phenolic hydroxyl group is added to a
cyanate compound (for example, JP-A-2003-128928, JP-A-2003-128753
and JP-A-2003-128784) is known. However, the phosphorus compounds
also have a toxic problem. Furthermore, melamine, guanidine, etc.,
are used as a nitrogen compound. However, the nitrogen compound is
insufficient in flame resistance when it is used alone.
[0007] On the other hand, metal hydroxides such as aluminum
hydroxide and magnesium hydroxide are known as a flame retardant.
However, there is apprehension that the incorporation of the metal
hydroxide causes a decrease in dielectric characteristics, heat
resistance, impact resistance or moldability. Further, when an
inorganic filler such as a spherical fused silica is used in a
large amount for decreasing a combustible component and securing
flame retardancy, as is used for an epoxy resin, the melt viscosity
of a molding material rises, a deterioration in moldability occurs,
a decrease in adhesive strength occurs because of a decrease in
wettability to a base material, or a deterioration in dielectric
characteristics occurs, in some cases.
[0008] Further, antimony type flame retardants such as antimony
trioxide, which are widely used in combination with a brominated
epoxy resin, have a problem such as an apprehension of chronic
toxicity since they are toxic substances. From the above
viewpoints, thermosetting resins themselves are desired to have
higher flame retardancy than ever.
[0009] Moreover, a lot of attempts have been made for improving
heat resistance, low dielectric constant, low dielectric loss
tangent, weather resistance, chemical resistance, low absorption,
high fracture resistance, moldability, adhesion, etc., in addition
to flame retardancy. For example, JP-A-6-228308 discloses a method
for producing a cured product excellent in thermal stability by
combining a monocyanate with a dicyanate and JP-A-6-49238 discloses
a method which aims at a low dielectric constant and a low
dielectric loss tangent by combining a monofunctional cyanate ester
compound with a polyfunctional cyanate ester compound.
[0010] Further, JP-A-6-122763 discloses a method for producing a
low-absorptive, flame-retardant cyanate ester curable resin
composition by incorporating a halogen-containing monofunctional
cyanate ester in order to achieve a low dielectric constant and a
low dielectric loss tangent. JP-A-6-122763 have a description about
the cyanate ester in a wide range. However, an aromatic
monofunctional cyanate ester having bromine as a functional group
is essential for the maintenance of flame retardancy, so that
JP-A-6-122763 does not succeeds in improving the flame retardancy
with the cyanate ester resin alone.
[0011] Further, Japanese Kohyo No. 2002-531989 provides an aromatic
cyanate ester compound containing at least two rings each of which
is bonded with a group containing an unsaturated group.
JP-A-63-250359 provides a fluorine-containing dicyanate ester.
JP-A-2002-206048 provides a method for attaining flame retardancy
by using a phenol novolak type cyanate ester. However, none of them
teach a cured product formed of a cyanate ester compound alone
which product practically has all of low dielectric
characteristics, flame retardancy and heat resistance.
SUMMARY OF THE INVENTION
[0012] It is an object of the present invention to provide a novel
cyanate ester compound capable of giving a cured product not only
having excellent flame retardancy but also having a low dielectric
constant, a low dielectric loss tangent and high heat resistance, a
curable resin composition containing the above compound and a cured
product obtained by curing the above resin composition.
[0013] The present inventors have made diligent studies and as a
result found that a cyanate ester compound represented by the
formula (1), preferably compounds represented by the formulae
(2)-(4), more preferably compounds represented by the formulae
(5)-(7), gives a cured product which is excellent in flame
resistance and has a low dielectric constant, a low dielectric loss
tangent and high heat resistance. Accordingly, the present
inventors have completed the present invention.
[0014] The present invention provides a cyanate ester compound
represented by the formula (1), preferably a cyanate ester compound
represented by any one of the formulae (2) to (4), more preferably
a compound represented by any one of the formulae (5) to (7), 2
[0015] wherein Ar.sub.2 represents a phenylene group, a naphthylene
group or a biphenylene group, Ar.sub.1 represents a naphthylene
group or a biphenylene group when Ar.sub.2 is a phenylene group, or
Ar.sub.1 represents a phenylene group, a naphthylene group or a
biphenylene group when Ar.sub.2 is a naphthylene group or a
biphenylene group, R.sub.x represents all substituents of Ar.sub.1,
each R.sub.x is the same or different and represents hydrogen, an
alkyl group or an aryl group, R.sub.y represents all substituents
of Ar.sub.2, each R.sub.y is the same or different and represents
hydrogen, an alkyl group or an aryl group, and n is an integer of 1
to 50, 3
[0016] wherein R.sub.1 to R.sub.4 are the same or different and
represent hydrogen or an alkyl group, n is an integer of 1 to 50,
and the position of each substituent of aromatic rings can be
arbitrarily selected, 4
[0017] wherein R.sub.1 to R.sub.4 are the same or different and
represent hydrogen or an alkyl group, n is an integer of 1 to 50,
and the position of each substituent of aromatic rings can be
arbitrarily selected, 5
[0018] wherein R.sub.1 and R.sub.2 are the same or different and
represent hydrogen or an alkyl group, n is an integer of 1 to 50,
and the position of each substituent of aromatic rings can be
arbitrarily selected, 6
[0019] wherein n is an integer of 1 to 50, 7
[0020] wherein n is an integer of 1 to 50.
[0021] The present invention further provides a curable resin
composition containing the above cyanate ester compound represented
by the formula (1), preferably a curable resin composition
containing the cyanate ester compound represented by anyone of the
formulae (2) to (4), more preferably a curable resin composition
containing the cyanate ester compound represented by any one of the
formulae (5) to (7), and a cured product obtained by curing the
above resin composition.
EFFECT OF THE INVENTION
[0022] The cyanate ester of the present invention is capable of
giving a cured product excellent in flame retardancy and has a low
dielectric constant, a low dielectric loss tangent and a high glass
transition temperature. For this reason, it is remarkably useful as
a high function polymer material and can be used as a thermally and
electrically excellent material for wide applications such as an
electrical insulating material, an adhesive, a laminating material,
a resist and a buildup laminate material.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention will be explained in detail
hereinafter. In the cyanate ester compound represented by the
formula (1), Ar.sub.2 represents a phenylene group, a naphthylene
group or a biphenylene group, and Ar.sub.1 represents a naphthylene
group or a biphenylene group when Ar.sub.2 is a phenylene group or
Ar.sub.1 represents a phenylene group, a naphthylene group or a
biphenylene group when Ar.sub.2 is a naphthylene group or a
biphenylene group. Specific examples of Ar.sub.1 and Ar.sub.2
include 1,4-phenylene group, 1,3-phenylene group, 4,4'-biphenylene
group, 2,4'-biphenylene group, 2,2'-biphenylene group,
2,3'-biphenylene group, 3,3'-biphenylene group, 3,4'-biphenylene
group, 2,6-naphthylene group, 1,5-naphthylene group,
1,6-naphthylene group, 1,8-naphthylene group, 1,3-naphthylene group
and 1,4-naphthylene group.
[0024] In the cyanate ester compound represented by the formula
(1), R.sub.x represents all substituents of Ar.sub.1 and each
R.sub.x is the same or different and represents hydrogen, an alkyl
group or an aryl group. Specific examples of R.sub.x include a
methyl group, an ethyl group, an isopropyl group, a n-butyl group,
an i-butyl group, a tert-butyl group and an isomer pentyl group as
the alkyl group and a phenyl group, an alkyl phenyl group, a
naphthyl group, an alkyl naphthyl group, a biphenyl group and an
alkyl biphenyl group as the aryl group.
[0025] In the cyanate ester compound represented by the formula
(1), R.sub.y represents all substituents of Ar.sub.2 and each
R.sub.y is the same or different and represents hydrogen, an alkyl
group or an aryl group. Specific examples of R.sub.y include a
methyl group, an ethyl group, an isopropyl group, an n-butyl group,
an i-butyl group, a tert-butyl group and an isomer pentyl group as
the alkyl group and a phenyl group, an alkyl phenyl group, a
naphthyl group, an alkyl naphthyl group, a biphenyl group and an
alkyl biphenyl group as the aryl group.
[0026] In the cyanate ester compound represented by the formula
(1), n is an integer of from 1 to 50.
[0027] The cyanate ester compound represented by the formula (1) is
preferably a cyanate ester compound represented by any one of the
formulae (2) to (4), more preferably a cyanate ester compound
represented by any one of the formulae (5) to (7). In the cyanate
ester compound represented by the formula (2), R.sub.1 to R.sub.4
are the same or different and represent hydrogen or an alkyl group,
preferably an alkyl group having 1 to 4 carbon atoms, n is an
integer of 1 to 50, and the position of each substituent of
aromatic rings can be arbitrarily selected.
[0028] In the cyanate ester compound represented by the formula
(3), R.sub.1 to R.sub.4 are the same or different and represent
hydrogen or an alkyl group, preferably an alkyl group having 1 to 4
carbon atoms, n is an integer of 1 to 50, and the position of each
substituent of aromatic rings can be arbitrarily selected.
[0029] In the cyanate ester compound represented by the formula
(4), R.sub.1 and R.sub.2 are the same or different and represent
hydrogen or an alkyl group, preferably an alkyl group having 1 to 4
carbon atoms, n is an integer of 1 to 50, and the position of each
substituent of aromatic rings can be arbitrarily selected.
[0030] The process for the production of the compound of the
formula (1), including the compounds of the formulae (2) to (7), is
not specially limited and may be selected from all processes which
are present as a cyanate synthesis.
[0031] For example, IAN HAMERTON, "Chemistry and Technology of
Cyanate Ester Resins", BLACKIE ACADEMIC & PROFESSIONAL,
discloses a synthesis process for general cyanate ester compounds.
U.S. Pat. No. 3,553,244 provides a method in which a reaction is
carried out in a solvent in the presence of a base such that
cyanogen halide is always present in an excessive amount based on
the base. JP-A-7-53497 discloses a method in which a synthesis is
carried out with using a tertiary amine as a base in an excessive
amount based on cyanogen chloride. Japanese Kohyo No. 2000-501138
discloses a method which carries out a reaction between
trialkylamine and cyanogen halide according to a continuous plug
flow method. Japanese Kohyo No. 2001-504835 discloses a method in
which tert-ammonium halide, which is a by-product obtained in a
reaction between phenol and a cyanogen halide in a nonaqueous
solution in the presence of a tert-amine, is treated with a cation
and anion exchange-couple. Further, Japanese Patent No. 2991054
discloses a method in which a tertiary amine and cyanogen halide
are concurrently added to a phenol compound in the presence of a
solvent separable from water to allow them to react, washing with
water and liquid separation are carried out, and purification by
precipitation from the thus-obtained solution is carried out by
using a poor solvent such as a secondary or tertiary alcohol or a
hydrocarbon.
[0032] The compound of the formula (1) can be obtained by reacting
a phenol compound represented by the formula (8) with cyanogen
chloride in a solvent in the presence of a basic compound. Further,
there can be adopted a synthesis method in which a salt of the
phenol compound of the formula (8) and a basic compound is formed
in a solution containing water and then the salt is reacted with
cyanogen chloride by a two-phase interface reaction to synthesize
the compound of the formula (1). 8
[0033] wherein Ar.sub.1, Ar.sub.2, R.sub.x, R.sub.y and n are as
defined in the formula (1).
[0034] As a general synthesis procedure of cyanate ester, the
phenol compound of the formula (8) is dissolved in an organic
solvent, a basic compound such as a tertiary amine is added and
then the resultant mixture is reacted with an excessive amount of a
cyanogen halide. In this system, since the cyanogen halide is
always present in an excessive amount, it is said to be possible to
inhibit imidocarbonate, which is to be generated by a reaction
between phenolate anion and cyanate ester. However, since the
excessive cyanogen halide reacts with the tertiary amine to
generate dialkylcyanamide, it is necessary to keep the reaction
temperature at 10.degree. C. or less, preferably 0.degree. C. or
less, more preferably -10.degree. C. or less.
[0035] Other than the above method, the order of addition in the
reaction, etc., may be arbitrarily selected. For example, after the
phenol compound is dissolved in solvent, a basic compound such as a
tertiary amine and cyanogen halide or its solution may be
alternately dropwise added or may be currently supplied. Further, a
mixture solution of the phenol compound and a basic compound such
as a tertiary amine and cyanogen halide or its solution may be
concurrently supplied. In each case, the reaction is a large
exothermic reaction, while it is necessary to keep the reaction
temperature at 10.degree. C. or less, preferably 0.degree. C. or
less, more preferably -10.degree. C. or less, for the purpose of
inhibiting a side reaction, etc.
[0036] The reaction may be carried out in any form. It may be a
batch reaction, a semibatch reaction or a continuous flow
reaction.
[0037] The basic compound such as a tertiary amine and the cyanogen
halide are added in a total amount of 0.1 to 8 mole, preferably 1
to 3 mol, per 1.0 mol of a phenolic hydroxyl group of the phenol
compound. In particular, when the phenol compound has a substituent
having a steric hindrance at the ortho position of hydroxyl group,
the total amount of the basic compound such as a tertiary amine and
the cyanogen halide needed is increased as compared with a case
where such a substituent is not present.
[0038] The cyanogen halide to be used is typically cyanogen
chloride, cyanogen bromide, etc.
[0039] In the phenol compound represented by the formula (8), as
the phenol compound to be used, Ar.sub.2 represents a phenylene
group, a naphthylene group or a biphenylene group, and Ar.sub.1
represents a naphthylene group or a biphenylene group when Ar.sub.2
is a phenylene group, or Ar.sub.1 represents a phenylene group, a
naphthylene group or a biphenylene group when Ar.sub.2 is a
naphthylene group or a biphenylene group. Specific examples of
Ar.sub.1 and Ar.sub.2 include 1,4-phenylene group, 1,3-phenylene
group, 4,4'-biphenylene group, 2,4'-biphenylene group,
2,2'-biphenylene group, 2,3'-biphenylene group, 3,3'-biphenylene
group, 3,4'-biphenylene group, 2,6-naphthylene group,
1,5-naphthylene group, 1,6-naphthylene group, 1,8-naphthylene
group, 1,3-naphthylene group and 1,4-naphthylene group. R.sub.x
represents all substituents of Ar.sub.1, and each R.sub.x is the
same or different and represents hydrogen, an alkyl group or an
aryl group. Specific examples of R.sub.x include a methyl group, an
ethyl group, an isopropyl group, a n-butyl group, an i-butyl group,
a tert-butyl group and an isomer pentyl group as the alkyl group
and a phenyl group, an alkyl phenyl group, a naphthyl group, an
alkyl naphthyl group, a biphenyl group and an alkyl biphenyl group
as the aryl group. R.sub.y represents all substituents of Ar.sub.2,
and each R.sub.y is the same or different and represents hydrogen,
an alkyl group or an aryl group. Specific examples of R.sub.y
include a methyl group, an ethyl group, an isopropyl group, an
n-butyl group, an i-butyl group, a tert-butyl group and an isomer
pentyl group as the alkyl group and a phenyl group, an alkyl phenyl
group, a naphthyl group, an alkyl naphthyl group, a biphenyl group
and an alkyl biphenyl group as the aryl group. Further, n is an
integer of from 1 to 50.
[0040] The compound of the formula (8) can be obtained by, for
example, the methods disclosed in Japanese Patent No. 3122834 and
Japanese Patent No. 2866747. Concretely, there are a method in
which a bishalogenomethyl compound such as a compound represented
by Ar.sub.2--(CH.sub.2--X).sub.2 is reacted with a phenol compound
in the presence of an acid catalyst or in the absence of a
catalyst, and a method in which a bis(alkoxymethyl) compound such
as Ar.sub.2--(CH.sub.2OR).sub.2 or a bis(hydroxymethyl) compound
such as Ar.sub.2--(CH.sub.2OH).sub.2 is reacted with a phenol
compound in the presence of an acid catalyst.
[0041] The basic compound to be used is not specially limited and
is selected from organic and inorganic bases. The organic base is
preferably an organic base having a high solubility. Particularly,
a tertiary amine with less side reaction is preferable. The
tertiary amine is freely selected from alkyl amines, aryl amines
and cycloalkyl amines. Specific examples thereof include
trimethylamine, triethylamine, methyldiethylamine, tripropylamine,
tributylamine, methyldibutylamine, dinonylmethylamine,
dimethylstearylamine, dimethylcyclohexylamine, diethylaniline,
pyridine and quinoline.
[0042] The solvent to be used for the reaction includes ketone
solvents such as acetone, methyl ethyl ketone and methyl isobutyl
ketone, aromatic solvents such as benzene, toluene and xylene,
ether solvents such as diethyl ether, dimethylcellosolve, diglyme,
tetrahydrofuran, methyltetrahydrofuran, dioxane and
tetraethyleneglycoldimethylether, halogenated hydrocarbon solvents
such as methylene chloride, chloroform, carbon tetrachloride and
chlorobenzene, alcohol solvents such as methanol, ethanol,
isopropanol, methylcellosolve and propyleneglycolmonomethylether,
aprotic polar solvents such as N,N-dimethylformamide,
N-methylpyrrolidone, 1,3-dimehtyl-2-imidazolidone and dimethyl
sulfoxide, nitrile solvents such as acetonitrile and benzonitrile,
nitro solvents such as nitromethane and nitrobenzene, ester
solvents such as ethyl acetate and ethyl benzoate, hydrocarbon
solvents such as cyclohexane. These solvents may be used alone or
in combination in accordance with a reactant.
[0043] As a post-treatment after the reaction, generally, a
hydrochloric salt of the basic compound such as a tertiary amine,
which is a byproduct, is removed by filtration or washing with
water. Taking the washing with water into consideration, it is
preferable to use a solvent which is not miscible with water in the
reaction. Further, there is adopted a method using an acidic
aqueous solution such as a dilute hydrochloric acid for removing
excess amines in the washing step. For removing a water content
from a sufficiently-washed reaction liquid, it is possible to carry
out a drying operation by a general method such as sodium sulfate
or magnesium sulfate.
[0044] After these operations, a concentration operation, a
precipitation operation or a crystallization operation is carried
out. For the concentration, since the cyanate ester compound has an
unstable structure, a pressure reduction is carried out with
keeping 150.degree. C. or lower. For the precipitation or the
crystallization, a solvent having a low solubility can be used. For
example, an ether solvent, a hydrocarbon solvent such as hexane or
an alcohol solvent may be dropwise added to the reaction solution.
Otherwise, the reaction solution may be inversely dropwise
added.
[0045] For washing a crude product obtained, there can be adopted a
method in which a concentrate of the reaction solution or a
precipitated crystal is washed with an ether solvent, a hydrocarbon
solvent such as hexane or an alcohol solvent. Further, a crystal
obtained by concentrating the reaction solution may be again
dissolved and then recrystallized. Further, when crystallization is
carried out, the reaction solution may be simply concentrated or
cooled. By removing volatile contents from the thus-obtained
product according to a method such as drying under reduced
pressure, there can be obtained a high-purity cyanate ester
compound.
[0046] Then, the curable resin composition of the present invention
will be explained. The above curable resin composition is
characterized by containing the aforementioned cyanate ester
compound of the present invention. The curable resin composition of
the present invention may contain a cyanate ester compound other
than the cyanate ester compound of the present invention, an epoxy
resin, an oxetane resin and/or a compound having a polymerizable
unsaturated group.
[0047] The cyanate ester compound other than the cyanate ester
compound of the present invention can be selected from known
cyanate ester compounds. Examples of thereof include bisphenol A
dicyanate, bisphenol F dicyanate, bisphenol M dicyanate, bisphenol
P dicyanate, bisphenol E dicyanate, phenol novolak type cyanate,
cresol novolak type cyanate, dicyclopentadiene novolak type
cyanate, tetramethyl bisphenol F dicyanate and biphenol dicyanate.
These cyanate ester compounds may be used alone or in
combination.
[0048] When the cyanate ester compound is cured, a known curing
catalyst may be used. Examples thereof include metal salts such as
zinc octylate, zinc naphthenate, cobalt naphthenate, copper
naphthenate and acetylacetone iron, and compounds having an active
hydroxyl group such as phenol, an alcohol and an amine.
[0049] The epoxy resin can be selected from known epoxy resins.
Examples thereof include a bisphenol A type epoxy resin, a
bisphenol F type epoxy resin, a biphenyl type epoxy resin, a phenol
novolak type epoxy resin, a cresol novolak type epoxy resin, a
xylene novolak type epoxy resin, triglycidyl isocyanurate, an
alicyclic epoxy resin, a dicyclopentadiene novolak type epoxy
resin, a biphenyl novolak type epoxy resin, a phenol aralkyl
novolak type epoxy resin and a naphthol aralkyl novolak type epoxy
resin. These epoxy resins may be used alone or in combination.
[0050] The oxetane resin can be selected from generally known
oxetane resins. Examples thereof include alkyl oxetanes such as
oxetane, 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane and
3,3-dimethyloxetane, 3-methyl-3-methoxymethyloxetane,
3,3'-di(trifluoromethyl)perfluoxetane, 2-chloromethyloxetane,
3,3-bis(chrolomethyl)oxetane, OXT-101 (tradename, supplied by
TOAGOSEI Co., Ltd.) and OXT-121 (trade name, supplied by TOAGOSEI
Co., Ltd.). These oxetane resins may be used alone or in
combination.
[0051] When the curable resin composition of the present invention
contains the epoxy resin and/or the oxetane resin, an epoxy resin
curing agent and/or an oxetane resin curing agent may be used. The
above epoxy resin curing agent can be selected from generally known
epoxy resin curing agents. Examples thereof include imidazole
derivatives such as 2-methylimidazole, 2-ethyl-4-methylimidazole,
2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole,
1-cyanoethyl-2-ethyl-4-methylimidazole,
2-phenyl-4,5-dihydroxymethylimidazole and
2-phenyl-4-methyl-5-hydroxymeth- ylimidazole; amine compounds such
as dicyandiamide, benzyldimethylamine and
4-methyl-N,N-dimethylbenzylamine; and phosphine compounds such as
phosphonium compounds. The oxetane resin curing agent can be
selected from known cationic polymerization initiators.
Commercially available examples include SAN-AID SI-60L, SAN-AID
SI-80L, SAN-AID SI-100L (supplied by Sanshin Chemical Industry Co.,
Ltd.), CI-2064 (supplied by Nippon Soda Co., Ltd.), IRGACURE261
(supplied by Ciba Specialty Chemicals), ADEKAOPTMER SP-170,
ADEKAOPTMER SP-150, (supplied by Asahi Denka Kogyo K.K.), and
CYRACURE UVI-6990 (supplied by Union Carbide Corporation). The
cationic polymerization initiators can be used as the epoxy resin
curing agent. These curing agents may be used alone or in
combination.
[0052] The compound having a polymerizable unsaturated group can be
selected from generally known compounds having a polymerizable
unsaturated group. Examples thereof include vinyl compounds such as
ethylene, propylene, styrene, divinyl benzene and divinyl biphenyl;
(meth)acrylates of monohydric and polyhydric alcohols such as
methyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate,
2-hydroxypropyl(meth)acrylate, polypropylene glycol
di(meth)acrylate, trimethylol propane di(meth)acrylate, trimethylol
propane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate and
dipentaerythritol hexa (meth)acrylate; epoxy(meth)acrylates such as
a bisphenol A type epoxy(meth)acrylate and a bisphenol F type epoxy
(meth)acrylate; a benzocyclobutene resin and a (bis)maleimide
resin. These compounds having an unsaturated group may be used
alone or in combination.
[0053] When the compound having an unsaturated group is used, a
known polymerization initiator may be used as required. The
polymerization initiator can be selected from known polymerization
initiators. Examples thereof include peroxides such as benzoyl
peroxide, p-chlorobenzoyl peroxide, di-t-butylperoxide, diisopropyl
peroxycarbonate and di-2-ethylhexylperoxycarbonate, and azo
compounds such as azobisisobutylonitrile.
[0054] Further, when the curable resin composition of the present
invention is produced, there may be added a known additive such as
a thermoplastic resin, an inorganic filler, a color pigment, an
antifoamer, a surface conditioner, a flame retardant, an
ultraviolet absorber, an antioxidant and a flow regulator, as
required. Examples of the inorganic filler include silicas such as
natural silica, fused silica and amorphous silica, white carbon,
titanium white, aerosil, alumina, talc, natural mica, synthetic
mica, kaolin, clay, aluminum hydroxide, barium sulfate, E-glass,
A-glass, NE-glass, C-glass, L-glass, D-glass, S-glass and M-glass
G20. The so-obtained curable resin composition is suitable for
various applications such as an electrical insulating material, a
resin for a resist, a semiconductor-sealing material, an adhesive
for a printed wiring board, a buildup laminate material, a resin
for fiber-reinforced plastics, a sealing resin for a liquid crystal
display panel, a resin for a color filter of liquid crystal, a
coating composition, various coating agents and an adhesive.
[0055] The cured product of the present invention can be obtained
by curing the curable resin composition of the present invention,
obtained by the above process, under heat. When the curing
temperature is too low, the curable resin composition does not
undergo curing. When it is too high, the cured product
deteriorates. Therefore, the curing temperature is preferably in
the range of from 150.degree. C. to 300.degree. C.
[0056] The present invention will be explained more concretely with
reference to Examples hereinafter, while the present invention
shall not be specially limited to these Examples.
EXAMPLES
Example A1
Synthesis of Cyanate Ester of Biphenyl Novolak (Formula (9): to be
Referred to as "G65C")
[0057] 9
[0058] Biphenyl novolak having 1.1 mol of OH groups (supplied by
Nippon Kayaku Co., Ltd., KAYAHARD-GPHG65) and 1.6 mol of
triethylamine were dissolved in 900 ml of 3-methyltetrahydrofuran,
to obtain a solution 1. The solution 1 was dropwise added to 2,500
g of a methylene chloride solution of 2.2 mol of cyanogen chloride
at -10.degree. C. over 1.5 hours. The mixture was stirred for 30
minutes. Then, a mixed solution of 0.4 mol of triethylamine and 100
g of methylene chloride was dropwise added, and the resultant
mixture was further stirred for 30 minutes to complete the
reaction. A hydrochloride of triethylamine was separated by
filtration. The thus-obtained filtrate was washed with 1,000 ml of
0.1 N hydrochloric acid, and then washing with 1,000 ml of water
was repeated four times. After drying with sodium sulfate,
evaporation was carried out at 75.degree. C., to obtain a crystal
of a yellow solid. The crystal was washed with diethyl ether and
hexane and then dried under a reduced pressure, to obtain a cyanate
ester G65C of biphenyl novolak. Identification was carried out by
an infrared absorption spectrum measurement.
Example B1-1
Production of Cured Product
[0059] The cyanate ester G65C of biphenyl novolak obtained in
Example 1 in an amount shown in Table 1 was added in a short-neck
flask. The cyanate ester G65C was molten under heat at 150.degree.
C. and degassed with a vacuum pump. Then, zinc octylate was added
and the resultant mixture was stirred for 1 minute. The stirred
mixture was casted in a mold composed of a glass plate (120
mm.times.120 mm.times.5 mmt), a polyimide film (Kapton 200H: DU
PONT-TORAY CO., LTD.) and an O-ring made of fluoro rubber (S-100:
MORISEI Co., Ltd.), and it was cured by heating in an oven at
170.degree. C. for 1 hour and at 230.degree. C. for 9 hours. After
cooling, the polyimide film was removed by polishing to obtain a
cured product of cyanate ester compound.
[0060] The obtained cured product was evaluated for properties by
the following methods.
[0061] Glass transition temperature (Tg): Obtained according to a
dynamic viscoelasticity measurement (DMA). The measurement was
carried out at an oscillation frequency of 10 GHz.
[0062] Dielectric constant and dielectric loss tangent: Obtained
according to a cavity resonant oscillation method.
[0063] Flame resistance: Aflame resistance test was carried out
according to UL94. The size of a sample was 10 mm.times.70
mm.times.1.5 mm.
[0064] Table 1 shows the evaluation results of physical
properties.
Example B1-2
[0065] A cured product was obtained in the same manner as in
Example B1-1 except that 50 parts by weight of the G65C obtained in
Example 1 and 50 parts by weight of bisphenol A dicyanate Skylex,
supplied by Mitsubishi Gas Chemical Company, Inc., were used.
[0066] Table 1 shows the evaluation results of physical properties
of the cured product.
Comparative Example B1
[0067] A cured product was obtained in the same manner as in
Example B1-1 except that the G65C was replaced with bisphenol A
dicyanate Skylex, supplied by Mitsubishi Gas Chemical Company,
Inc., alone.
[0068] Table 1 shows the evaluation results of physical properties
of the cured product.
Comparative Example B2
[0069] A cured product was obtained in the same manner as in
Example B1-1 except that the G65C was replaced with phenol novolak
cyanate PT 30 supplied by LONZA.
[0070] Table 1 shows the evaluation results of physical properties
of the cured product.
1 TABLE 1 Example Example Comparative Comparative B1-1 B1-2 Example
B1 Example B2 Mixing G65C 100 50 -- -- amount Bisphenol A -- 50 100
-- (Part by dicyanate weight) Phenol -- -- -- 100 novolak cyanate
Zinc octylate 0.05 0.05 0.05 0.05 Properties Tg (.degree. C.: DMA)
259 283 304 286 Dielectric constant 2.79 2.76 2.73 3.02 (10 GHz)
Dielectric loss tangent 0.005 0.007 0.011 0.015 (10 GHz) Flame
resistance (UL94) V-0 V-1 Entirely Entirely burned burned
Example A2
Synthesis of Cyanate Ester of Biphenyl Novolak Monomer (Formula
(10): to be Referred to as "BPN-CN")
[0071] 10
[0072] A biphenyl novolak monomer having 0.4 mol of OH groups and
0.4 mol of triethylamine were dissolved in 600 ml of
3-methyltetrahydrofuran, to obtain a solution 1. The solution 1 was
dropwise added to a mixed solution of 220 g of a methylene chloride
solution of 0.8 mol of cyanogen chloride and 400 g of
3-methyltetrahydrofuran at -10.degree. C. over 1.5 hours. The
mixture was stirred for 30 minutes. Then, a mixed solution of 0.32
mol of triethylamine and 80 g of 3-methyltetrahydrofuran was
dropwise added, and the resultant mixture was further stirred for
30 minutes to complete the reaction. A hydrochloride of
triethylamine was separated by filtration. The thus-obtained
filtrate was washed with 1,000 ml of 0.1 N hydrochloric acid, and
then washing with 1,000 ml of water was repeated four times. After
drying with sodium sulfate, evaporation was carried out at
75.degree. C., to obtain a crystal of a yellow solid. The crystal
was washed with diethyl ether and hexane and then dried under a
reduced pressure, to obtain a cyanate ester BPN-CN of biphenyl
novolak monomer. Identification was carried out by an infrared
absorption spectrum measurement.
Example A3
2,6-bis(4-cyanate-3,5-dimethylphenylmethyl) naphthalene (Formula
(11): to be Referred to as "26XNDC")
[0073] 11
[0074] 0.4 mol of
2,6-bis(4-phenoxy-3,5-dimethylphenylmethyl)naphthalene and 1.3 mol
of triethylamine were dissolved in 600 ml of
3-methyltetrahydrofuran, to obtain a solution 1. The solution 1 was
dropwise added to a mixed liquid of 2,500 g of a methylene chloride
solution of 2 mol of cyanogen chloride and 1,000 g of chloroform at
-10.degree. C. over 1.5 hours. The mixture was stirred for 30
minutes. Then, a mixed solution of 0.6 mol of triethylamine and 100
g of methylene chloride was dropwise added, and the resultant
mixture was further stirred for 30 minutes to complete the
reaction. The reaction liquid was filtered. Then, the thus-obtained
filtrate was washed with 1,000 ml of 0.1 N hydrochloric acid, and
then washing with 1,000 ml of water was repeated four times. After
drying with sodium sulfate, a concentration operation was carried
out at 75.degree. C. As the concentration operation advanced, a
white crystal precipitated. The white crystal was washed with
diethyl ether and hexane and then dried under a reduced pressure,
to obtain a white crystal,
2,6-bis(4-cyanate-3,5-dimethylphenylmethyl)naphth- alene (26XNDC).
Identification was carried out by an infrared absorption spectrum
measurement.
Example A4
Synthesis of Cyanate Ester of Naphthol Aralkyl (Formula (12): to be
Referred to as "SN485CN")
[0075] 12
[0076] Naphthol aralkyl having 0.47 mol of OH groups (supplied by
Nippon Steel Chemical Co., Ltd., SN485N) and 0.7 mol of
triethylamine were dissolved in 500 ml of chloroform, to obtain a
solution 1. The solution 1 was dropwise added to 300 g of a
chloroform solution of 0.93 mol of cyanogen chloride at -10.degree.
C. over 1.5 hours. The mixture was stirred for 30 minutes. Then, a
mixed solution of 0.1 mol of triethylamine and 30 g of chloroform
was dropwise added, and the resultant mixture was further stirred
for 30 minutes to complete the reaction. The thus-obtained reaction
liquid was washed with 500 ml of 0.1 N hydrochloric acid, and then
washing with 500 ml of water was repeated four times. After drying
with sodium sulfate, evaporation was carried out at 75.degree. C.,
to obtain a brown solid. The solid was washed with diethyl ether
and hexane and then dried under a reduced pressure, to obtain a
cyanate ester of naphthol aralkyl. Identification was carried out
by an infrared absorption spectrum measurement.
Example B2
[0077] A cured product was obtained in the same manner as in
Example B1-1 except that the G65C was replaced with BPN-CN obtained
in Example A2.
[0078] Table 2 shows the evaluation results of physical properties
of the cured product.
Example B3
[0079] A cured product was obtained in the same manner as in
Example B1-1 except that the G65C was replaced with a mixture of 50
parts by weight of 26XNDC obtained in Example A3 and 50 parts by
weight of bisphenol A dicyanate Skylex, supplied by Mitsubishi Gas
Chemical Company, Inc.
[0080] Table 2 shows the evaluation results of physical properties
of the cured product.
Example B4
[0081] A cured product was obtained in the same manner as in
Example B1-1 except that the G65C was replaced with SN485CN
obtained in Example A4.
[0082] Table 2 shows the evaluation results of physical properties
of the cured product.
2 TABLE 2 Example B2 Example B3 Example B4 Mixing BPN-CN 100 -- --
amount 26XNDC -- 50 -- (Part by SN485CN -- -- 100 weight) Bisphenol
A -- 50 -- dicyanate Zinc octylate 0.05 0.05 0.05 Properties Tg
(.degree. C.: DMA) 231 276 274 Dielectric 2.77 2.7 2.86 constant
(10 GHz) Dielectric 0.004 0.007 0.004 loss tangent (10 GHz) Flame
V-0 V-0 V-0 resistance (UL94)
* * * * *