U.S. patent application number 13/979063 was filed with the patent office on 2013-11-21 for liquid resol-type phenolic resin.
This patent application is currently assigned to SUMITOMO BAKELITE CO., LTD.. The applicant listed for this patent is Yuji Suzuki. Invention is credited to Yuji Suzuki.
Application Number | 20130310612 13/979063 |
Document ID | / |
Family ID | 46507045 |
Filed Date | 2013-11-21 |
United States Patent
Application |
20130310612 |
Kind Code |
A1 |
Suzuki; Yuji |
November 21, 2013 |
LIQUID RESOL-TYPE PHENOLIC RESIN
Abstract
A liquid resol-type phenolic resin obtained by reacting a phenol
(A), and a secondary and/or tertiary alkylamine compound (B) in the
presence of a basic catalyst. The nitrogen content relative to the
total weight of the liquid resol-type phenolic resin is preferably
from 3 to 30% by weight. Further, the secondary and/or tertiary
alkylamine compound (B) is preferably hexamethylenetetramine.
Moreover, the molar ratio between the phenol (A) and the secondary
and/or tertiary alkylamine compound (B) preferably satisfies
(B)/(A)=0.13 to 0.35.
Inventors: |
Suzuki; Yuji; (Fujieda-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Suzuki; Yuji |
Fujieda-shi |
|
JP |
|
|
Assignee: |
SUMITOMO BAKELITE CO., LTD.
Tokyo
JP
|
Family ID: |
46507045 |
Appl. No.: |
13/979063 |
Filed: |
December 28, 2011 |
PCT Filed: |
December 28, 2011 |
PCT NO: |
PCT/JP2011/080405 |
371 Date: |
July 10, 2013 |
Current U.S.
Class: |
568/720 |
Current CPC
Class: |
C08G 8/08 20130101; C08G
8/10 20130101; C08G 73/024 20130101; C07C 39/21 20130101 |
Class at
Publication: |
568/720 |
International
Class: |
C07C 39/21 20060101
C07C039/21 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 14, 2011 |
JP |
2011-005440 |
Claims
1. A liquid resol-type phenolic resin obtained by reacting a phenol
(A), and a secondary and/or tertiary alkylamine compound (B) in
presence of a basic catalyst.
2. The liquid resol-type phenolic resin according to claim 1,
wherein a nitrogen content relative to a total weight of the liquid
resol-type phenolic resin is from 3 to 30% by weight.
3. The liquid resol-type phenolic resin according to claim 1,
wherein the secondary and/or tertiary alkylamine compound (B) is
hexamethylenetetramine.
4. The liquid resol-type phenolic resin according to claim 1,
wherein the phenol (A) and the secondary and/or tertiary alkylamine
compound (B) are reacted in a molar ratio that satisfies
(B)/(A)=0.13 to 0.35.
5. The liquid resol-type phenolic resin according to claim 1, which
is used for impregnation.
Description
TECHNICAL FIELD
[0001] The present invention relates to a liquid resol-type
phenolic resin.
[0002] Priority is claimed on Japanese Patent Application No.
2011-005440, filed Jan. 14, 2011, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] Phenolic resins, which are thermosetting resins, are widely
used as binders for bonding together materials that function as
substrates, and because phenolic resins have excellent mechanical
properties, electrical properties and adhesiveness, they are used
in a wide variety of fields.
[0004] In order to obtain a molded item, a liquid phenolic resin is
typically used by impregnating a substrate containing a fiber as a
main component. Examples of this type of application include FRP,
copper clad laminates, and wet paper friction materials.
[0005] Among such applications, the amount of friction materials
using a phenolic resin as a binder is increasing in automobiles and
railway carriages and the like. In particular, liquid resol-type
phenolic resins are generally used for the friction materials used
in the automatic transmission and the like of automatic vehicles,
so-called wet friction materials. The properties demanded of these
phenolic resins used in wet friction materials continue to increase
year by year, and in particular, demands for increased flexibility
of the phenolic resin have continued to grow, with the object of
improving the coefficient of friction and the durability. However,
despite having excellent mechanical properties, the cured products
of typical phenolic resins tend to be hard and brittle, and cannot
be said to exhibit excellent flexibility.
[0006] As a method of addressing the problems outlined above, tests
are being conducted into improving the flexibility by using a
drying oil or the like as a denaturant in the reaction used when
synthesizing the phenolic resin (for example, see Patent Document
1).
[0007] However, this type of modified phenolic resin suffers a
number of problems, including a marked deterioration in the
strength after a heat history, and a short cycle life.
DOCUMENTS OF RELATED ART
Patent Document
[0008] [Patent Document 1] Japanese Unexamined Patent Application,
First Publication No. Hei 9-59599
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0009] The present invention provides a liquid resol-type phenolic
resin that can be used to obtain a molded item having the excellent
properties of a phenolic resin, such as superior heat resistance
and curability, as well as excellent flexibility.
Means to Solve the Problems
[0010] This type of object is achieved by the following aspects [1]
to [5] of the present invention.
[1] A liquid resol-type phenolic resin obtained by reacting a
phenol (A), and a secondary and/or tertiary alkylamine compound (B)
in the presence of a basic catalyst. [2] The liquid resol-type
phenolic resin disclosed above in [1], wherein the nitrogen content
relative to the total weight of the liquid resol-type phenolic
resin is from 3 to 30% by weight. [3] The liquid resol-type
phenolic resin disclosed above in [1] of [2], wherein the secondary
and/or tertiary alkylamine compound (B) is hexamethylenetetramine.
[4] The liquid resol-type phenolic resin disclosed above in any one
of [1] to [3], wherein the phenol (A) and the secondary and/or
tertiary alkylamine compound (B) are reacted in a molar ratio that
satisfies (B)/(A) =0.13 to 0.35. The liquid resol-type phenolic
resin disclosed above in any one of [1] to [4], which is used for
impregnation.
Effects of the Invention
[0011] When the liquid resol-type phenolic resin of the present
invention is used as a binder, a molded item having excellent heat
resistance, curability and flexibility can be obtained.
MODES FOR CARRYING OUT THE INVENTION
[0012] A more detailed description of the liquid resol-type
phenolic resin of the present invention is presented below, but the
invention is in no way limited by these examples. Additions,
omissions, substitutions, and other modifications can be made
without departing from the spirit or scope of the present
invention.
[0013] The liquid resol-type phenolic resin of the present
invention is obtained by reacting a phenol (A), and a secondary
and/or tertiary alkylamine compound (B) in the presence of a basic
catalyst.
[0014] Various methods can be used to obtain the liquid resol-type
phenolic resin used in the present invention, and although there
are no particular limitations on the method used, the liquid
resol-type phenolic resin can be synthesized, for example, by
reacting a typical phenol and a hexamine in the presence of a basic
catalyst.
(A) Phenol
[0015] Examples of the phenol used in the liquid resol-type
phenolic resin of the present invention include phenol, cresols
such as o-cresol, m-cresol and p-cresol, xylenols such as
2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol and
3,5-xylenol, ethylphenols such as o-ethylphenol, m-ethylphenol and
p-ethylphenol, isopropylphenol, butylphenols such as butylphenol
and p-tert-butylphenol, alkylphenols such as p-tert-amylphenol,
p-octylphenol, p-nonylphenol and p-cumylphenol, halogenated phenols
such as fluorophenol, chlorophenol, bromophenol and iodophenol,
monohydric phenol substituted compounds such as p-phenylphenol,
aminophenol, nitrophenol, dinitrophenol and trinitrophenol, as well
as monohydric phenols such as 1-naphthol and 2-naphthol, and
polyhydric phenols such as resorcinol, alkylresorcinols,
pyrogallol, catechol, alkylcatechols, hydroquinone,
alkylhydroquinones, phloroglucinol, bisphenol A, bisphenol F,
bisphenol S and dihydroxynaphthalene. These compounds may be used
individually, or two or more compounds may be used as a mixture.
The phenol used in the present invention is preferably soluble in
the organic solvent described below.
[0016] Among these phenols, a compound selected from among phenol,
the cresols and bisphenol A is preferable. This enables an
improvement in the mechanical strength of a molded item obtained
using the liquid resol-type phenolic resin of the present
invention.
(B) Secondary and/or Tertiary Alkylamine Compound
[0017] Examples of the secondary and/or tertiary alkylamine
compound (B) used in the liquid resol-type phenolic resin of the
present invention include secondary alkylamine compounds such as
dimethylamine and diethylamine, and tertiary alkylamines compounds
such as triethylamine, tetramethylethylenediamine and
hexamethylenetetramine. These compounds may be used individually,
or two or more compounds may be combined.
[0018] Among these compounds, the use of hexamethylenetetramine is
preferable. By using hexamethylenetetramine, the reaction can be
conducted without using an aldehyde source such as formalin.
[0019] Examples of the basic catalyst used in preparing the liquid
resol-type phenolic resin of the present invention include alkali
metal hydroxides such as sodium hydroxide, lithium hydroxide and
potassium hydroxide, ammonia water, tertiary amines such as
triethylamine, oxides and hydroxides of alkaline earth metals such
as calcium, magnesium and barium, and other alkaline substances
such as sodium carbonate. These compounds may be used individually,
or two or more compounds may be combined. There are no particular
limitations on the amount used of the basic catalyst, but the
amount is typically within a range from 0.01 to 0.1 mol per 1 mol
of the aforementioned phenol (A).
[0020] The proportions of the various components of the liquid
resol-type phenolic resin of the present invention, relative to
1,000 parts by weight of the liquid resol-type phenolic resin, are
from 0 to 100 parts by weight, and preferably from 0 to 50 parts by
weight, of the phenol, from 0 to 80 parts by weight, and preferably
from 0 to 40 parts by weight, of the secondary and/or tertiary
alkylamine compound, and from 0 to 20 parts by weight, and
preferably from 0 to 10 parts by weight, of the basic catalyst.
[0021] In the liquid resol-type phenolic resin of the present
invention, the nitrogen content relative to the total weight of the
liquid resol-type phenolic resin is preferably from 3 to 30% by
weight. This nitrogen content is more preferably from 5 to 10% by
weight.
[0022] If the nitrogen content is higher than this range, then the
viscosity increases and it becomes difficult to take out the liquid
resol-type phenolic resin from a vessel. Further, if the nitrogen
content is less than this range, then the effect of the invention
in improving the flexibility and the heat resistance
diminishes.
[0023] In the liquid resol-type phenolic resin of the present
invention, for each 1 mol of the phenol (A), the number of moles of
the secondary and/or tertiary alkylamine compound (B) is preferably
from 0.13 to 0.35 mol. This amount is more preferably from 0.18 to
0.30 mol.
[0024] This ensures that when the liquid resol-type phenolic resin
of the present invention is used for impregnation, the resin
exhibits good impregnation properties, and can also improve the
flexibility of the molded item.
[0025] The liquid resol-type phenolic resin of the present
invention is obtained by reacting the phenol (A) and the secondary
and/or tertiary alkylamine compound (B) described above in the
presence of the aforementioned basic catalyst. The reaction
temperature is preferably from 50 to 110.degree. C., and more
preferably from 80 to 100.degree. C.
[0026] In the liquid resol-type phenolic resin of the present
invention, an organic solvent can be used to dilute the resin.
There are no particular limitations on the organic solvent used for
this dilution, and examples include alcohol-based organic solvents
such as methanol, ethanol, isopropanol and butanol, ketone-based
organic solvents such as acetone, methyl ethyl ketone and methyl
isobutyl ketone, aromatic hydrocarbon solvents such as toluene and
ethylbenzene, and mixtures of these solvents.
[0027] The liquid resol-type phenolic resin of the present
invention can be used for impregnation. Impregnation refers to
permeation of the resin into gaps within the texture or the
structure of a substrate or the like. Examples of the substrate
subjected to the impregnation include substrates formed using metal
fiber, glass fiber, carbon fiber or chemical fiber or the like. The
present invention can be used particularly favorably for wet paper
friction material applications, and when used for a wet paper
friction material application, a paper substrate containing not
only the types of fiber components mentioned above, but also filled
with a friction modifier such as cashew dust or diatomaceous earth
or the like can be used.
[0028] The obtained molded item has the excellent properties of a
phenolic resin such as superior heat resistance and curability, and
also exhibits excellent flexibility.
EXAMPLES
[0029] The present invention is described below in further detail
using a series of examples.
[0030] In the examples described below, "parts" refers to "parts by
weight", and "%" refers to "% by weight".
Example 1
1. Production of Liquid Resol-Type Phenolic Resins
[0031] A reaction apparatus fitted with a stirrer, a reflux
condenser and a thermometer was charged with 1,000 parts by weight
of phenol, 370 parts by weight of hexamethylenetetramine (0.25 mol
per 1 mol of phenol), 100 parts by weight of methanol, 100 parts by
weight of acetone and 20 parts by weight of a 50% aqueous solution
of sodium hydroxide, and the resulting mixture was heated to
95.degree. C. and held at that temperature for 3 hours.
[0032] Subsequently, 1,200 parts by weight of acetone was added,
and the temperature was cooled to 40.degree. C. or lower, yielding
2,700 parts by weight of a liquid resol-type phenolic resin.
Example 2
[0033] With the exception of altering the amount of
hexamethylenetetramine to 450 parts by weight (0.30 mol per 1 mol
of phenol), preparation was performed using the same method as
Example 1, yielding 2,780 parts by weight of a liquid resol-type
phenolic resin.
Example 3
[0034] With the exception of altering the amount of
hexamethylenetetramine to 270 parts by weight (0.18 mol per 1 mol
of phenol), preparation was performed using the same method as
Example 1, yielding 2,600 parts by weight of a liquid resol-type
phenolic resin.
Example 4
[0035] With the exceptions of replacing the phenol from Example 1
with a mixed cresol containing 63% of meta-cresol and 27% of
para-cresol, and altering the amount of hexamethylenetetramine to
320 parts by weight (0.25 mol per 1 mol of the phenol), preparation
was performed using the same method as Example 1, yielding 2,650
parts by weight of a liquid resol-type phenolic resin.
Comparative Example 1
[0036] In Example 1, the 370 parts by weight of
hexamethylenetetramine was replaced with 1,600 parts by weight of a
37% aqueous solution of formalin, and the reaction was conducted.
The resultant was dewatered under reduced pressure at 80.degree. C.
for 30 minutes, 1,800 parts by weight of acetone was added, and the
temperature was cooled to 40.degree. C. or lower, yielding 4,100
parts by weight of a liquid resol-type phenolic resin.
2. Evaluation of Liquid Resol-Type Phenolic Resins
[0037] Using the liquid resol-type phenolic resins obtained in the
examples and the comparative example, impregnated papers were
prepared. Commercially available filter paper (120 mm.times.10
mm.times.thickness 1 mm) was used as the substrate.
[0038] The liquid resol-type phenolic resins obtained in the
examples and the comparative example were each diluted with acetone
to prepare a solution having a resin concentration of 30%, a sample
of the aforementioned filter paper was impregnated with the
solution, and the impregnated filter paper was then dried and cured
in an oven at 190.degree. C. for 30 minutes to obtain a test piece.
The tensile strength of the thus obtained test piece was measured
in accordance with JIS P 8113 "Paper and Board--Determination of
Tensile Properties", under normal conditions and following
treatment at 240.degree. C. for 1 hour. Further, the Rockwell
hardness of each test piece was measured in accordance with JIS K
7202 "Method of Rockwell Hardness Test for Plastics". The tensile
strength was measured as an indicator of the mechanical strength of
the cured product (molded item), and in the present invention, a
higher numerical value is preferable. Further, the Rockwell
hardness was measured as an indicator of the hardness of the cured
product (molded item), and in the present invention, a lower
numerical value is preferable.
[0039] The results of the above evaluations are summarized in Table
1.
TABLE-US-00001 TABLE 1 Exam- Exam- Exam- Comparative ple 1 ple 2
ple 3 Example 4 Example 1 Tensile strength 13.1 13.9 14.0 13.0 12.3
under normal conditions (MPa) Tensile strength 8.9 8.7 8.5 8.4 8.1
following heat treatment at 240.degree. C. (MPa) Rockwell 75.5 74.0
74.0 76.0 83.3 hardness
[0040] Examples 1 to 4 are liquid resol-type phenolic resins of the
present invention. It was found that the cured products of the
obtained resins had superior flexibility as indicated by a low
Rockwell hardness, and excellent heat resistance as indicated by a
high degree of strength retention (tensile strength) following the
heat treatment at 240.degree. C.
[0041] In contrast, Comparative Example 1 is a resol-type resin
obtained using phenol and formaldehyde, and the flexibility was
poor as indicated by a high Rockwell hardness, and the reduction in
the tensile strength following the heat treatment at 240.degree. C.
was large, indicating that a resin having excellent heat resistance
could not be obtained.
INDUSTRIAL APPLICABILITY
[0042] The present invention can provide a liquid resol-type
phenolic resin that can be used to obtain a molded item having the
excellent properties of a phenolic resin, such as superior heat
resistance and curability, as well as excellent flexibility.
Accordingly, the present invention is extremely useful
industrially.
* * * * *