U.S. patent application number 09/734734 was filed with the patent office on 2001-06-21 for process for producing phenol resin.
Invention is credited to Asami, Masakatsu, Kobayashi, Yoshikazu.
Application Number | 20010004664 09/734734 |
Document ID | / |
Family ID | 26580543 |
Filed Date | 2001-06-21 |
United States Patent
Application |
20010004664 |
Kind Code |
A1 |
Asami, Masakatsu ; et
al. |
June 21, 2001 |
Process for producing phenol resin
Abstract
A novolak-type phenol resin with less unreacted phenol and a
narrow molecular weight distribution is produced in high yield by
reaction of a phenol with an aldehyde using an organophosphonic
acid as a catalyst, while keeping a water concentration of reaction
system at not more than 30% by weight and a reaction temperature at
110.degree. C.-200.degree. C.
Inventors: |
Asami, Masakatsu;
(Yaizu-shi, JP) ; Kobayashi, Yoshikazu;
(Fujieda-shi, JP) |
Correspondence
Address: |
Beveridge, DeGrandi, Weilacher & Young
Suite 800
1850 M Street, N.W.
Washington
DC
20036
US
|
Family ID: |
26580543 |
Appl. No.: |
09/734734 |
Filed: |
December 13, 2000 |
Current U.S.
Class: |
528/141 ;
528/129; 528/137 |
Current CPC
Class: |
C08G 8/00 20130101; C08G
8/08 20130101; C08G 8/20 20130101; C08G 8/04 20130101; C08G 8/10
20130101 |
Class at
Publication: |
528/141 ;
528/137; 528/129 |
International
Class: |
C08G 008/04; C08K
005/5317 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 16, 1999 |
JP |
11-357047 |
Oct 19, 2000 |
JP |
2000-318893 |
Claims
1. A process for producing a novolak-type phenol resin, which
comprises conducting reaction of a phenol with an aldehyde by use
of an organophosphonic acid as a catalyst.
2. A process according to claim 1, wherein the reaction is
conducted while keeping a water concentration of reaction system at
not more than 30% by weight and a reaction temperature at
110.degree. C.-200.degree. C.
3. A process according to claim 1 or 2, wherein the
organophosphonic acid is represented by the following general
formula (1):R--PO(OH).sub.2 (1) where R is a group containing
carbon atoms and at least one of --COOH and --PO(OH).sub.2.
Description
[0001] The present invention relates to a process for producing a
novolak type phenol resin with less unreacted phenol and a narrow
molecular weight distribution in high yield. The novolak-type
phenol resin produced according to the present invention is used as
a suitable binder for molding materials, friction materials,
grinding materials, sealants, etc.
[0002] Heretofore, a novolak-type phenol resin has been obtained by
reaction of a phenol with an aldehyde, using an inorganic or
organic acid such as hydrochloric acid, sulfuric acid, phosphoric
acid, phosphorous acid, oxalic acid, p-toluenesulfonic acid, etc.
as a catalyst. A novolak-type phenol resin can be adjusted in the
molecular weight generally by changing a charge ratio of a phenol
to an aldehyde, etc. but has a broader molecular weight
distribution. The ordinary means for narrowing the molecular weight
distribution includes a method of conducting the reaction in an
organic solvent and a method of removing low-molecular weight
components by steam distillation or solvent washing. In the case of
the former method, no low-molecular weight novolak-type phenol
resin can be obtained, whereas in the case of the latter method,
the yield is considerably lowered.
[0003] An object of the present invention is to produce a
novolak-type phenol resin with less unreacted phenols and a narrow
molecular weight distribution in high yield.
[0004] As a result of extensive studies to attain the object, the
present inventors have found a process for producing a novolak-type
phenol resin, which comprises conducting reaction of a phenol with
an aldehyde by use of an organophosphonic acid as a catalyst and
have established the present invention.
[0005] According to a preferable mode of the present invention,
reaction of a phenol with an aldehyde is carried out by keeping a
water concentration of reaction system at not more than 30% by
weight and a reaction temperature at 110.degree. C.-200.degree.
C.
[0006] According to another preferable mode of the present
invention, an organophosphonic acid represented by the following
general formula (1) is used:
R--PO(OH).sub.2 (1)
[0007] where R is a group containing carbon atoms and at least one
of --COOH and --PO(OH).sub.2.
[0008] FIG. 1 is a liquid chromatographic chart of the novolak-type
phenol resin obtained in Example 1.
[0009] FIG. 2 is a liquid chromatographic chart of the novolak-type
phenol resin obtained in Example 2.
[0010] FIG. 3 is a liquid chromatographic chart of the novolak-type
phenol resin obtained in Comparative Example 1.
[0011] The phenol for use in the present invention is not
particularly limited, and preferably includes at least one of
phenols selected from phenol, ortho-cresol, metha-cresol,
para-cresol, xylenol, para-t-butylphenol, para-octylphenol,
para-phenylphenol, bisphenol A, bisphenol F, resorcinol, etc.
[0012] The aldehyde for use in the present invention is not
particularly limited, and preferably includes formaldehyde,
acetaldehyde, butyraldehyde, acrolein, etc. or mixtures thereof.
Materials serving as a source for generating such an aldehyde or
solutions of such an aldehyde can be also used.
[0013] Molar ratio of phenol to aldehyde as reactants is
1.0:0.1-3.0, preferably 0.5-1.0. All the amounts of phenol and
aldehyde can be charged in one lump before the start of reaction,
and then the catalyst can be added thereto to start the reaction,
or in order to suppress heat generation at the initial stage of
reaction, phenol and the catalyst can be charged at first and then
aldehyde can be consecutively added thereto to start the
reaction.
[0014] The organophosphonic acid as a catalyst for use in the
present invention is an organic compound containing a phosphono
group --PO(OH).sub.2 and is not particularly limited, but the
organo-phosphonic acid represented by the following general formula
(1) is preferable from the viewpoint of producing novolak-type
phenol resin with less unreacted phenol and a narrow molecular
weight distribution in high yield:
R--PO(OH).sub.2 (1)
[0015] where R is a group containing carbon atoms and at least one
of --COOH and --PO(OH).sub.2.
[0016] The oranophosphonic acid represented by the general formula
(1) includes aminopolyphosphonic acids such as ethylenediamine
tetrakismethylenephosphonic acid,
ethylenediaminebismethylenephosphonic acid,
aminotrimethylenephosphonic acid, .beta.
-aminoethylphosphono-N,N-d- iacetic acid and
aminomethylphosphono-N,N-diacetic acid, and
1-hydroxyethylidene-1,1'-diphosphonic acid,
2-phosphonobutane-1,2,4-trica- roxylic acid, etc. From the
viewpoint of the object of the present invention,
aminotrimethylenephosphonic acid, 1-hydroxyethylidene-1,1'-dip-
hosphonic acid and 2-phosphonobutane-1,2,4-tricarboxylic acid,
which can be commercially produced in bulk at a low cost, are
preferable.
[0017] 0.001-4.0 parts by mole, preferably 0.01-0.5 parts by mole,
of organophosphonic acid is added to one part by mole of phenol.
The higher the amount of organophosphonic acid, the more remarkable
the effect of the present invention, i.e. on the production of a
novolak-type phenol resin with less unreacted phenol and a narrow
molecular weight distribution in high yield. Even if the catalyst
amount exceed 4.0 parts by mole, the effect can be no more
increased, whereas below 0.001 parts by mole, the catalyst effect
is substantially lost.
[0018] An acid usually used in the production of a novolak-type
phenol resin, such as oxalic acid, sulfuric acid, hydrochloric
acid, p-toluenesulfonic acid, etc. can be used at the same time.
Simultaneous use of such an acid is effective particularly for
reaction promotion in the higher molecular weight region such as 4-
or higher nucleus members, and thus can be regarded as an effective
means for controlling the molecular weight distribution.
[0019] In the present process for producing a novolak-type phenol
resin, reaction conditions of keeping a water concentration of
reaction system at not more than 30% by weight and a reaction
temperature at 110.degree.-200.degree. C. are effective for
selective reaction of not only unreacted phenol but also a
novolak-type phenol resin in the low molecular weight region such
as 2- and 3-nucleus members and thus are conditions for effectively
narrowing the molecular weight distribution. In other words,
reaction of unreacted phenol can be readily carried out even under
conditions outside the above-mentioned reaction conditions, i.e. at
a higher water concentration and a lower temperature, but the
selective reaction in the low molecular weight region such as 2-
and 3-nucleus members is not satisfactory and the molecular weight
distribution tends to be broadened.
[0020] Water concentration of reaction system in the present
invention is a proportion of water to total amount of phenol,
aldehyde, novolak-type phenol resin, organophosphonic acid, etc.
present in the reaction system. Water includes water added at the
charging, water derived from the charged raw materials such as
water contained in the added aldehyde, water contained in the added
organophosphonic acid, and water of crystallization in the
organophosphonic acid, water of condensation formed by the
reaction, etc. A concentration of these kinds of water present in
the reaction system is not more than 30% by weight, preferably
1-20% by weight.
[0021] Water concentration of reaction system can be calculated by
dividing total amount of the water contained in the charged raw
materials and the water of condensation formed by the reaction in
the reaction system by total amount of all the charged materials.
When the reaction is carried out while removing water by
distillation, a water concentration of reaction system is
calculated on the basis of the amount of water obtained by
subtracting the amount of distilled water from the total amount of
the water in the charged raw materials and the water of
condensation formed by the reaction.
[0022] The lower the water concentration, the higher the effect on
the production of a novolak-type phenol resin with less unreacted
phenol and a narrow molecular weight distribution in high yield.
Thus, not more than 20% by weight is preferable. However, at too
low a water concentration, the organophosphonic acid becomes highly
viscous or solidified, lowering the catalytic effect. Therefore,
not less than 1% by weight, i.e. a water concentration nearly
corresponding to the content of water of crystallization, is
preferable. When the water concentration exceeds 30% by weight, the
effect will be no more increased.
[0023] In the present invention, the reaction temeprature is
preferably 110.degree.-200.degree. C. Below 110.degree. C., the
catalyst organophosphonic acid becomes highly viscous or solidified
under the above-mention condition of low water concentration,
lowering the catalytic effect, whereas above 200.degree. C.
decomposition of organophosphonic acid and novolak-type phenol
resin will take place. Decomposition of organophosphonic acid and
novolak-type phenol resin will take place less at a low
temperature, and a temperature range for obtaining the satisfactory
catalyst effect without becoming highly viscous and solidified at a
water concentration of 1-20% by weight is 130.degree.-160.degree.
C.
[0024] In the reaction under the atmospheric pressure, the reflux
temperature nearly corresponds to 110.degree.-200.degree. C. at a
water concentration of not more than 30% by weight, and thus the
reaction under the atmospheric pressure is a preferable condition
for controlling the temperature and water concentration. Other
conceivable reaction conditions include solvent reflux dehydration
reaction using a non-aqueous solvent such as butanol, propanol,
etc., high pressure reaction, etc.
[0025] Furthermore, conditions of removing formed water of
condensation by distillation, etc. while adding an aldehyde are
preferable because the water concentration of reaction system can
be kept constant, but attention must be paid to such a disadvantage
that the unreacted phenol is likely to be removed together with
water by the distillation.
[0026] To overcome such a disadvantage, the reaction is carried out
so that the unreacted phenol may not be distilled away until the
unreacted phenol reaches a predetermined amount or less, and then
after or while removing water by distillation the reaction is
continued while keeping the water concentration at not more than
30% by weight and the reaction temperature at 110.degree.
C.-200.degree. C.
[0027] After the reaction, neutralization and water washing can be
carried out for the catalyst removal. If required, atmospheric
distillation, subatmospheric distillation, steam distillation, etc.
can be also carried out for removal of water, organic solvent or
even unreacted phenol.
[0028] The reason why a novolak-type phenol resin with a narrow
molecular weight distribution can be produced in high yield by the
present invention, using an organophosphonic acid as a catalyst
seems to be based on the following facts.
[0029] The organophosphonic acid for use in the present invention
has such properties as a very high solubility in water with easy
hydration, a low solubility in phenol and a lower solubility in
novolak-type phenol resin which tends to decrease with its
increasing molecular weight. Thus, phase separation takes place
during the reaction. That is, an aqueous phase rich in the
organophosphonic acid as a catalyst is separated from an organic
phase comprising phenol and novolak-type phenol resin,
substantially free from the catalyst. Phenol and low molecular
weight components such as 2-nucleus members are more liable to
dissolve in the aqueous phase and the dissolved matters will react
with aldehyde. But no substantial dissolution in the aqueous phase
takes place in the high molecular weight region and consequently no
reaction proceeds. The reacted novolak-type phenol resin by
dissolution in the aqueous phase is quickly extracted into the
organic phase and no further reaction proceeds.
[0030] In this manner, there is a difference in reaction rate
between the low molecular weight region and the high molecular
weight region, resulting in production of a novolak-type phenol
resin with less unreacted phenol and a narrow molecular weight
distribution in high yield.
[0031] The present invention is characterized by using an
organophosphonic acid as a catalyst and preferably by keeping a
water concentration of reaction system at not more than 30% by
weight and a reaction temperature at 110.degree.-200.degree. C. as
reaction conditions. Reason why a novolak-type phenol resin with
less unreacted phenol and a narrow molecular weight distribution
can be produced in high yield in the preferable mode of the present
invention seems to be based on the following facts.
[0032] Low water concentration of reaction system, i.e. not more
than 30% by weight, and high reaction temperature, i.e. not less
than 110.degree. C., can give rise to the following effects.
[0033] First, the high reaction temperature makes even the low
molecular weight region of 2- and 3-nucleus members easily dissolve
into the aqueous phase, enabling the reaction to easily proceed in
the aqueous phase. The water concentration of reaction system is
kept low and the ionic concentration of the aqueous phase is kept
high. Thus, the boundary between the aqueous phase and the organic
phase can be maintained to distinctly separate the phases from each
other, thereby preventing reaction in the organic phase.
organophosphonic acid at a high concentration has an increased
viscosity and a solidifying tendency, but the high reaction
temperature can keep the organophosphonic acid in a molten state,
thereby preventing loss of catalytic function. Due to these
effects, a novolak-type phenol resin with less unreacted phenol and
a narrow molecular weight distribution can be effectively produced
in high yield.
[0034] The present invention will be described in detail below, by
means of Examples and Comparative Examples, where "parts" and "%"
are all by weight.
EXAMPLE 1
[0035] 1,000 parts of phenol and 200 parts of an aqueous 60%
1-hydroxyethylidene-1,1'-diphosphonic acid solution (Feliox 115,
product manufactured by Lion Corp.) were added to a 3-l
three-necked flask, followed by heating up to 100.degree. C. Then,
700 parts of an aqueous 35% formaldehyde solution was consecutively
added thereto over 30 minutes, and the resultant mixture was
subjected to reaction at 100.degree. C. for one hour with
refluxing. Then, the reaction mixture was subjected to atmospheric
distillation followed by heating up to 130.degree. C. and then to
subatmospheric distillation under reduced pressure of 5,000 Pa
followed by heating up to 150.degree. C., whereby 1,192 parts of
phenol resin A was obtained.
EXAMPLE 2
[0036] 1,000 parts of phenol and 240 parts of an aqueous 50%
aminotrimethylenephosphonic acid solution (Diquest 2000, product
manufactured by Solucia Japan K.K.) were added to a 3-l three
three-necked flask, followed by heating up to 100.degree. C. Then,
700 parts of an aqueous 35% formaldehyde solution was consecutively
added thereto over 30 minutes and the resultant mixture was
subjected to reaction at 100.degree. C. for one hour with
refluxing. Then, the reaction mixture was subjected to atmospheric
distillation followed by heating up to 130.degree. C. and then to
subatmospheric distillation under reduced pressure of 5,000 Pa
followed by heating up to 150.degree. C., whereby 1,178 parts of
phenol resin B was obtained.
Comparative Example 1
[0037] 1,000 parts of phenol and 10 parts of oxalic acid were added
to a 3-l three-necked flask, followed by heating up to 100.degree.
C. Then, 700 parts of an aqueous 35% formaldehyde solution was
consecutively added thereto over 30 minutes, and the resultant
mixture was subjected to reaction at 100.degree. C. for one hour
with refluxing. Then, the reaction mixture was subjected to
atmospheric distillation followed by heating up to 130.degree. C.
and then to subatmospheric distillation under reduced pressure of
5,000 Pa followed by heating up to 190.degree. C., whereby 957
parts of phenol resin I was obtained.
EXAMPLE 3
[0038] 1,000 parts of phenol and 200 parts of an aqueous 60%
1-hydroxyethylidene-1,1'-diphosphonic acid solution (Feliox 115,
product manufactured by Lion Corp.) were added to a 3-l
three-necked flask, followed by heating up to 100.degree. C. Then,
690 parts of an aqueous 37% formaldehyde solution was consecutively
added thereto over 30 minutes and the resultant mixture was
subjected to reaction at 100.degree. C. for one hour with
refluxing. After the reaction, the reaction mixture was sampled to
quantitatively determine unreacted phenol by gas chromatography.
Then, 500 parts of pure water was added thereto, and the aqueous
phase separated from the resin was removed. This water washing
process was carried out three times. Then, the washed reaction
mixture was subjected to atmospheric distillation followed by
heating up to 130.degree. C. and then to subatmospheric
distillation under reduced pressure of 5,000 Pa followed by heating
up to 150.degree. C., whereby 1,056 parts of phenol resin C was
obtained.
EXAMPLE 4
[0039] 1,000 parts of phenol and 240 parts of an aqueous 50%
aminotrimethylenephosphonic acid solution (Diquest 2000, product
manufactured by Solucia Japan K.K.) were added to a 3-l
three-necked flask, followed by heating up to 100.degree. C. Then,
690 parts of an aqueous 37% formaldehyde solution was consecutively
added thereto over 30 minutes, and the resultant mixture was
subjected to reaction at 100.degree. C. for one hour with
refluxing. After the reaction, the reaction mixture was sampled to
quantitatively determine unreacted phenol by gas chromatography.
Then, 500 parts of pure water was added thereto, and the aqueous
phase separated from the resin was removed. This water washing
process was carried out three times. Then, the washed reaction
mixture was subjected to atmospheric distillation followed by
heating up to 130.degree. C. and then to subatmospheric
distillation under reduced pressure of 5,000 Pa followed by heating
up to 150.degree. C., whereby 1,052 parts of phenol resin D was
obtained.
EXAMPLE 5
[0040] 1,000 parts of phenol and 240 parts of an aqueous 50%
2-phosphonobutane-1,2,4-tricarboxylic acid solution (PBTC, product
manufactured by Johoku Kagaku K.K.) were added to a 3-l
three-necked flask, followed by heating up to 100.degree. C. Then,
690 parts of an aqueous 37% formaldehyde solution was consecutively
added thereto over 30 minutes and the resultant mixture was
subjected to reaction at 100.degree. C. for one hour with
refluxing. After the reaction, the reaction mixture was sampled to
quantitatively determine unreacted phenol by gas chromatography.
Then, 500 parts of pure water was added thereto, and the aqueous
phase separated from the resin was removed. This water washing
process was carried out three times. Then, the washed reaction
mixture was subjected to atmospheric distillation followed by
heating up to 130.degree. C. and then to subatmospheric
distillation under reduced pressure of 5,000 Pa followed by heating
up to 150.degree. C., whereby 1,047 parts of phenol resin E was
obtained.
EXAMPLE 6
[0041] 1,000 parts of an aqueous 60%
1-hydroxyethylidene-1,1'-diphosphonic acid solution (Feliox 115,
product manufactured by Lion Corp) and 1,000 parts of phenol were
added to a 3-l three-necked flask, followed by heating up to
100.degree. C. Then, 690 parts of an aqueous 37% formaldehyde
solution was consecutively added thereto over one hour and the
resultant mixture was subjected to reaction at 100.degree. C. for
one hour with refluxing. After the reaction, the reaction mixture
was sampled to quantitatively determine unreacted phenol by gas
chromatography. Then, 500 parts of pure water was added thereto,
and the aqueous phase separated from the resin was removed. This
water washing process was carried out three times. Then, the washed
reaction mixture was subjected to atmospheric distillation followed
by heating up to 130.degree. C. and then to subatmospheric
distillation under reduced pressure of 5,000 Pa followed by heating
up to 150.degree. C., whereby 1,065 parts of phenol resin F was
obtained.
EXAMPLE 7
[0042] 1,000 parts of phenol and 600 parts of
1-hydroxyethylidene-1,1'-dip- hosphonic acid
(1-hydroxyethylidene-1,1'-diphosphonic acid (monohydrate) purity:
95% or higher; product manufactured by Kishida Kagaku K.K.) were
added to a 3-l three-necked flask, followed by heating up to
140.degree. C. Then, 277.5 parts of 92% paraformaldehyde was
consecutively added thereto over 30 minutes and the resultant
mixture was subjected to reaction at 126.degree. C. for one hour
with refluxing. Water concentration of reaction system was 2% at
the initial reaction stage and 12% at the end of reaction. After
the reaction, the reaction mixture was sampled to quantitatively
determine unreacted phenol by gas chromatography. Then, 500 parts
of pure water was added thereto, and the aqueous phase separated
from the resin was removed. This water washing process was carried
out three times. Then, the washed reaction mixture was subjected to
atmospheric distillation followed by heating up to 130.degree. C.
and to subatmospheric distillation under reduced pressure of 5,000
Pa followed by heating up to 150.degree. C., whereby 1,076 parts of
phenol resin G was obtained.
EXAMPLE 8
[0043] 1,000 parts of an aqueous 60%
1-hydroxyethylidene-1,1'-diphosphonic acid solution (Feliox 115,
product manufactured by Lion Corp.) was added to a 3-l three-necked
flask and subjected to atmospheric distillation to increase the
concentration to 80%. Then, 1,000 parts of phenol was added
thereto, followed by heating up to 100.degree. C. and consecutive
addition of 550 parts of an aqueous 37% formaldehyde solution
thereto over 30 minutes. Then, the mixture was subjected to
atmospheric distillation followed by heating up to 130.degree. C.
to adjust a water concentration of reaction system at 6%. Then, 140
parts of an aqueous 37% formaldehyde solution was added thereto
over 30 minutes during atmospheric distillation while keeping the
temperature at 130.degree. C. and the water concentration of
reaction system constantly at about 6%. Phenol loss by distillation
was found to be 0.3% on the basis of the charged phenol. Then, the
reaction was carried out at 140.degree. C. for one hour with
refluxing. After the reaction, the reaction mixture was sampled to
quantitatively determine unreacted phenol by gas chromatography.
Then, 500 parts of pure water was added thereto, and the aqueous
phase separated from the resin was removed. This water washing
process was carried out three times. The washed reaction mixture
was subjected to atmospheric distillation followed by heating up to
130.degree. C. and then to subatmospheric distillation under
reduced pressure of 5,000 Pa followed by heating up to 150.degree.
C., whereby 1,074 parts of phenol resin H was obtained.
Comparative Example 2
[0044] 1,000 parts of phenol and 10 parts of oxalic acid were added
to a 3-l three-necked flask, followed by heating up to 100.degree.
C. Then, 690 parts of an aqueous 37% formaldehyde solution was
consecutively added thereto and the reductant mixture was subjected
to reaction at 100.degree. C. for one hour with refluxing. After
the reaction, the reaction mixture was sampled to quantitatively
determine unreacted phenol by gas chromatography. Then, the
reaction mixture was subjected to atmospheric distillation followed
by heating up to 130.degree. C. and then to subatmospheric
distillation under reduced pressure of 5,000 Pa followed by heating
up to 190.degree. C., whereby 957 parts of phenol resin J was
obtained.
Comparative Example 3
[0045] 1,000 parts of phenol and 10 parts of oxalic acid were added
to a 3-l three-necked flask, followed by heating up to 100.degree.
C. Then, 690 parts of an aqueous 37% formaldehyde solution was
consecutively added thereto over 30 minutes and the resultant
mixture was subjected to reaction at 100.degree. C. for one hour
with refluxing. After the reaction, the reaction mixture was
sampled to quantitatively determine unreacted phenol by gas
chromatography. Then, 500 parts of pure water was added thereto,
and the aqueous phase separated from the resin was removed. This
water washing process was carried out three times. Then, the washed
reaction mixture was subjected to atmospheric distillation followed
by heating up to 130.degree. C. and then to subatmospheric
distillation under reduced pressure of 5,000 Pa followed by heating
up to 150.degree. C., whereby 972 parts of phenol resin K was
obtained.
[0046] Characteristics of the phenol resins obtained in Examples 1
and 2 and Comparative Example 1 are shown in Table 1 and their
liquid chromatographic charts are shown in FIGS. 1-3,
respectively.
[0047] Characteristics of the phenol resins obtained in Examples
3-8 and Comparative Examples 2 and 3 are shown in Table 2.
[0048] Characteristics shown in Tables 1 and 2 were determined in
the following manner:
[0049] 1. Resin yield: Parts of phenol resin produced on the basis
of 1,000 parts of charged phenol.
[0050] 2. Number average molecular weight (Mn) and weight average
molecular weight (Mw): determined by liquid chromatography.
[0051] 3. Unreacted phenol content: determined by gas
chromatography.
[0052] Gas chromatography: internal standard method according to
JIS K0114, using 2,5-xylenol as an internal standard substance.
[0053] 4. Softening point: determined according to JIS K-2531.
[0054] 5. Kinetic viscosity in 50% ethanol solution: determined in
50% ethanol solution at 25.degree. C., using a Cannon-Fenske
viscometer.
[0055] 6. 2-nucleus member content: determined from chart area
ratio obtained by liquid chromatography.
[0056] Liquid chromatography: determined by GPC, using GPC columns
(one G1000HXL column, two G2000HXL columns and one G3000HXL column)
manufactured by Tosoh Corp. with tetrahydrofuran as an eluent
solvent at a flow rate of 1.0 ml/min. and a column temperature of
40.degree. C. and with a differential refractometer as a
detector.
[0057] In Examples 1 and 2 and Comparative Example 1, molecular
weights were determined by means of an approximation straight line
plotted along peak 3 (peak position of 7-nucleus member), peak 7
(peak position of 3-nucleus member) and peak 10 (peak position of
phenol) in FIG. 2 showing a liquid chromatographic chart according
to Example 2, on the assumption that their molecular weights are
730, 306 and 94, respectively. In Examples 3-8 and Comparative
Examples 2 and 3, molecular weights were determined in terms of
standard polystyrene.
1 TABLE 1 Resin A B I (Ex. 1) (Ex. 2) (Comp. Ex. 1) Resin yield
(parts) 1192 1178 957 Number average 530 520 590 molecular weight
(Mn) Weight average 1097 1083 1424 molecular weight (Mw) Molecular
weight 2.1 2.1 2.4 distribution (Mw/Mn) Unreacted phenol (%) 1.2
1.4 2.3
[0058]
2 TABLE 2 J K C D E F G H (Comp. (Comp. (Ex. 3) (Ex. 4) (Ex. 5)
(Ex. 6) (Ex. 7) (Ex. 8) Ex. 2) Ex. 3) Resin yield (parts) 1056 1052
1047 1065 1076 1074 957 972 Unreacted phenol after 1.5 2.5 2.9 0.7
0.0 0.0 7.6 7.5 reflux reaction (%) Number average 583 572 496 550
600 616 1264 1203 molecular weight (Mn) Weight average 1547 1516
1325 1163 930 790 8263 8125 molecular weight (Mw) Molecular weight
2.65 2.65 2.67 2.12 1.55 1.28 6.51 6.75 distribution (Mw/Mn)
Softening point (.degree. C.) 100 99 98 98 93 96 103 99 Kinetic
viscosity in 68 67 63 66 43 43 122 108 50% ethanol solution
(25.degree. C., .mu.m.sup.2/s) Unreacted phenol (%) 1.1 1.9 2.0 0.5
0.0 0.0 1.8 4.7 2-nucleus member 12.1 12.1 10.5 9.9 6.0 2.5 13.1
13.0 content (%)
[0059] As evident from the results shown in Tables 1 and 2,
novolak-type phenol resins obtained in Examples 1-8 have narrower
molecular weight distributions, less unreacted phenol and higher
yields than those of Comparative Examples 1-3. Furthermore, as
evident from the results shown in Table 2, phenol resins obtained
in Examples 7 and 8 have narrower molecular weight distributions,
less unreacted phenol and higher yields than that obtained in
Example 6.
[0060] As described in the foregoing, a novolak-type phenol resin
with less unreacted phenol and a narrow molecular weight
distribution can be obtained in high yield in the present
invention.
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