U.S. patent application number 14/197516 was filed with the patent office on 2014-07-03 for phenolic resin composition for shell molding, resin coated sand for shell molding, and shell mold formed of the same.
This patent application is currently assigned to Asahi Organic Chemicals Industry Co., Ltd.. The applicant listed for this patent is Asahi Organic Chemicals Industry Co., Ltd.. Invention is credited to Keiichi MORI, Tomohiro TAKAMA.
Application Number | 20140187667 14/197516 |
Document ID | / |
Family ID | 43499029 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140187667 |
Kind Code |
A1 |
MORI; Keiichi ; et
al. |
July 3, 2014 |
PHENOLIC RESIN COMPOSITION FOR SHELL MOLDING, RESIN COATED SAND FOR
SHELL MOLDING, AND SHELL MOLD FORMED OF THE SAME
Abstract
Provided are a phenolic resin composition for shell molding that
has low thermal expansion properties and high flexibility, a resin
coated sand for shell molding obtained by using the same, and a
shell mold formed of the same. The phenolic resin composition for
shell molding that is capable of exhibiting advantageous mold
characteristic is obtained by a combination of a phenolic resin
that is obtained by a reaction of a phenol, a naphthol, and an
aldehyde, and a fatty acid amide.
Inventors: |
MORI; Keiichi; (Kasugai-Shi,
JP) ; TAKAMA; Tomohiro; (Ichinomiya-Shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Asahi Organic Chemicals Industry Co., Ltd. |
Nobeoka-Shi |
|
JP |
|
|
Assignee: |
Asahi Organic Chemicals Industry
Co., Ltd.
Nobeoka-Shi
JP
|
Family ID: |
43499029 |
Appl. No.: |
14/197516 |
Filed: |
March 5, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13270524 |
Oct 11, 2011 |
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14197516 |
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PCT/JP2010/061591 |
Jul 8, 2010 |
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13270524 |
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Current U.S.
Class: |
523/145 |
Current CPC
Class: |
B22C 1/2233 20130101;
B22C 1/2253 20130101; C09D 161/06 20130101; B22C 1/2246
20130101 |
Class at
Publication: |
523/145 |
International
Class: |
B22C 1/22 20060101
B22C001/22 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 23, 2009 |
JP |
2009-172135 |
Claims
1. A resin coated sand for shell molding, wherein a fire-refractory
particle is coated with a phenolic resin composition comprising a
resin consisting of a phenolic resin obtained by a reaction of a
phenol, a naphthol, and an aldehyde; and a fatty acid amide.
2. The resin coated sand for shell molding according to claim 1,
wherein a ratio of the phenol to the naphthol is in a range of from
95:5 to 50:50 by mass ratio.
3. The resin coated sand for shell molding according to claim 1,
wherein a ratio of the phenol to the naphthol is in a range of from
90:10 to 60:40 by mass ratio.
4. The resin coated sand for shell molding according to claim 1,
wherein the naphthol comprises at least one of 1-naphthol and
2-naphthol.
5. The resin coated sand for shell molding according to claim 1,
wherein a reaction molar ratio among the phenol (P), the naphthol
(N), and the aldehyde (F): F/(P+N) is in a range of from 0.40 to
0.80.
6. The resin coated sand for shell molding according to claim 1,
wherein the fatty acid amide is present in a range of from 1 to 15
parts by mass based on 100 parts by mass of the phenolic resin.
7. The resin coated sand for shell molding according to claim 1,
wherein the fatty acid amide is one of a monoamide, a substituted
amide, and a bisamide.
8. The resin coated sand for shell molding according to claim 1,
wherein the fatty acid amide is a fatty acid bisamide.
9. The resin coated sand for shell molding according to claim 8,
wherein the fatty acid bisamide is a saturated fatty acid
bisamide.
10. The resin coated sand for shell molding according to claim 1,
wherein the phenolic resin composition further comprises a silane
coupling agent.
11. The resin coated sand for shell molding according to claim 1,
wherein the phenolic resin composition is present in a range of
from 0.2 to 10 parts by mass based on 100 parts by mass of the
fire-refractory particle.
12. The resin coated sand for shell molding according to claim 1,
wherein a mold produced by using the resin coated sand has a
flexibility of at least 5.4 mm.
13. The resin coated sand for shell molding according to claim 1,
wherein the phenolic resin is obtained by a reaction of phenol,
naphthol and an aldehyde in the presence of an acid catalyst.
14. A shell mold obtained by forming and heat-curing the resin
coated sand for shell molding according to claim 1.
Description
[0001] This application is a divisional of U.S. application Ser.
No. 13/270,524, filed Oct. 11, 2011, which is a continuation of the
International Application No. PCT/JP2010/061591 filed on Jul. 8,
2010, which claims the benefit under 35 U.S.C. .sctn.119(a)-(d) of
Japanese Patent Application 2009-172135, filed on Jul. 23, 2009,
the entireties of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a phenolic resin
composition for shell molding, a resin coated sand for shell
molding, and a shell mold formed of the same. In particular, the
present invention relates to a phenolic resin composition for shell
molding that simultaneously solves problems related to thermal
expansion and flexibility, a resin coated sand obtained by using
the phenolic resin composition, and a shell mold obtained by using
the resin coated sand.
BACKGROUND OF THE INVENTION
[0003] Conventionally, in shell-mold casting, there is generally
used a shell mold that is formed by hot-forming a resin coated sand
obtained by kneading a fire-refractory particle (casting sand) and
a phenolic resin (binder), and as necessary a hardener such as
hexamethylenetetramine, into a desired shape. Hereinafter, the
resin coated sand is referred to as "RCS".
[0004] However, in casting process by using this kind of mold,
especially by using a mold which has a complex shape, e.g., a mold
for casting a molded product such as a cylinder head of an internal
combustion engine, there is a problem that a fracture or a crack
(hereinafter referred to as "crack" of the mold) is easily caused
on the mold during the casting process using the mold.
[0005] Meanwhile, it is conceivable that the crack of a mold can be
prevented by lowering coefficient of thermal expansion and
increasing the flexibility of mold. Patent document 1 discloses
that coefficient of rapid thermal expansion is lowered by using
bisphenol such as bisphenol A and bisphenol E as a component of
binder, so that low thermal expansion properties are obtained.
However, although such technique has sufficiently solved the
problem of crack of the mold, the technique has not sufficiently
solved the problem of flexibility.
[0006] Patent document 2 proposes a method in which crack of the
mold is prevented by incorporating polyethylene glycol having a
number average molecular weight of 1500 to 40000 into RCS. However,
thermal expansion properties and flexibility are not sufficiently
improved by this method, and thus further improvement is
needed.
[0007] Patent document 3 discloses that by using RCS formed by
coating surface of a casting sand with a phenolic resin excellent
in collapse resistance, which is produced by using at least
naphthol as phenol component, the improvement of regeneration rate
of the used shell sand and the stability of quality of the
regenerated sand can be obtained because collection of a mass of
shell when the mold is broken down after molding is improved. In
examples of patent document 3, a phenolic novolak resin and a
phenolic resole resin are exemplified that are obtained by a
reaction of .alpha.-naphthol, .beta.-naphthol, or a combination of
these naphthols, a phenol, and a formalin in the presence of a
catalyst such as hydrochloric acid and ammonia water. However,
particularly in the production of such resin by using the
hydrochloric acid as a catalyst, there is a safety problem caused
by vigorous reaction during the production of the resin, and also
there is a problem of corrosion of a die during the production of
the mold. Further, patent document 3 is silent about a phenolic
resin obtained by using an oxalic acid as a catalyst and RCS
obtained by using the same. Furthermore, it is also silent about a
crack of a mold which should be considered when producing a
mold.
PRIOR ART DOCUMENTS
Patent Documents
[0008] Patent Document 1: JP-A-59-178150 [0009] Patent Document 2:
JP-A-58-119433 [0010] Patent Document 3: JP-A-63-30144
SUMMARY OF INVENTION
[0011] The present invention has been made in the light of the
situations described above. It is therefore an object of the
present invention to provide: a phenolic resin composition for
shell molding that has low thermal expansion properties and high
flexibility; RCS obtained by using the phenolic resin: a process
for producing the RCS; and a shell mold obtained by using such
RCS.
[0012] The inventors of the present invention have conducted
intensive study and research about the phenolic resin composition
for shell molding in an effort to solve the above-described
problems and found that a phenolic resin composition having
effective properties can be obtained by a combination of a phenolic
resin that is obtained by a reaction of phenol components including
a phenol and a naphthol with an aldehyde, and a fatty acid amide.
Specifically, they found that in the mold produced by using RCS
formed by using the above-described phenolic resin composition, low
coefficient of thermal expansion and high flexibility are obtained.
Thus, the present invention has been completed.
[0013] It is therefore a gist of the present invention to provide a
phenolic resin composition for shell molding, comprising as
essential components: a phenolic resin obtained by a reaction of a
phenol, a naphthol, and an aldehyde; and a fatty acid amide.
[0014] According to a preferable aspect of the phenolic resin
composition for shell molding of the present invention, a ratio of
the phenol to the naphthol is in a range of from 95:5 to 50:50 by
mass ratio.
[0015] According to another preferable aspect of the present
invention, the naphthol comprises 1-naphthol and/or 2-naphthol.
[0016] According to a further preferable aspect of the present
invention, a reaction molar ratio among the phenol (P), the
naphthol (N), and the aldehyde (F): F/(P+N) is in a range of from
0.40 to 0.80.
[0017] According to a preferable aspect of the present invention,
the fatty acid amide is present in a range of from 1 to 15 parts by
mass based on 100 parts by mass of the phenolic resin.
[0018] According to a favorable aspect of the present invention,
the fatty acid amide is one of a monoamide, a substituted amide,
and a bisamide.
[0019] According to a still further preferable aspect of the
present invention, the fatty acid amide is a fatty acid bisamide,
more preferably, a saturated fatty acid bisamide.
[0020] According to another favorable aspect of the present
invention, the phenolic resin composition further comprises a
silane coupling agent.
[0021] It is another gist of the present invention to provide RCS
(resin coated sand) for shell molding characterized in that a
fire-refractory particle is coated with the phenolic resin
composition for shell molding according to the above aspects.
[0022] According to a preferable aspect of the RCS for shell
molding of the present invention, the phenolic resin composition is
present in a range of from 0.2 to 10 parts by mass based on 100
parts by mass of the fire-refractory particle.
[0023] It is a still further gist of the present invention to
provide a shell mold obtained by forming and heat-curing the resin
coated sand for shell molding according to the above aspects.
[0024] It is still further gist of the present invention to provide
a process for producing a resin coated sand, comprising the steps
of: (a) reacting a phenol, a naphthol, and an aldehyde in the
presence of a catalyst to obtain a phenolic resin; and (b) coating
a fire-refractory particle with the phenolic resin and a fatty acid
amide, which are mixed by melting, or coating a fire refractory
particle with the phenolic resin and a fatty acid amide, which are
used independently.
[0025] According to a preferable aspect of the present invention,
the catalyst comprises a divalent metal salt and/or an oxalic
acid.
[0026] The phenolic resin composition for shell molding according
to the present invention includes a phenolic resin that is obtained
by a reaction of a phenol, a naphthol, and an aldehyde, and a fatty
acid amide. Therefore, when a coating layer including the phenolic
resin composition is formed on a surface of a predetermined
fire-refractory particle so as to constitute RCS for shell molding
and such RCS is used to produce a shell mold, the obtained mold has
low thermal expansion properties and the flexibility of the mold
can be sufficiently improved. Accordingly, a problem of casting
defect of veining caused by a crack of the mold can be solved at
the same time. In addition, since the phenolic resin can be
produced without a corrosive component such as hydrochloric acid, a
problem of corrosion of a die during mold-forming may not be
caused. Thus, the present invention can have industrial advantages
that the intended shell mold can be easily and safely produced.
BRIEF DESCRIPTION OF DRAWING
[0027] FIG. 1 is an explanatory view showing how the "flexibility"
of mold is measured in examples.
DETAILED DESCRIPTION OF THE INVENTION
[0028] The phenolic resin constituting the phenolic resin
composition for shell molding of the present invention is obtained
by a reaction of a phenol, a naphthol, and an aldehyde in the
presence of a predetermined catalyst.
[0029] Here, examples of the phenol which is one of reaction
components of a phenolic resin include conventionally known phenol,
for example, phenol, alkylphenols such as cresol, xylenol,
p-tert-butylphenol and nonylphenol, polyhydric phenols such as
resorcinol, bisphenol F and bisphenol A, and a mixture thereof. Any
one of, or any combination thereof may be used.
[0030] The present invention is characterized by that the naphthol
is used as a phenol component together with the phenol. Due to this
characteristic, the properties of the phenolic resin to be obtained
are effectively improved. In terms of its ready availability and a
reduction of cost, for example, 1-naphthol, 2-naphthol, and a
mixture thereof may be used as the naphthol. Preferably, 1-naphthol
is employed because of its excellent reactivity with aldehyde, for
example. The phenol and naphthol are employed such that the ratio
of phenol to naphthol (1-naphthol and/or 2-naphthol) is in a range
of from 95:5 to 50:50 by mass. In other words, the naphthol is
employed so as to be present in an amount of 50% by mass or less,
based on the total phenol component. When the amount of the
naphthol is more than 50% by mass, an amount of generation of tar
during casting may be increased. On the other hand, when the amount
of the naphthol is less than 5% by mass, flexibility may not be
sufficiently exhibited. The ratio of phenol to naphthol is
preferably in a range of from 90:10 to 60:40, more preferably from
90:10 to 70:30, in view of the strength of the mold.
[0031] Examples of the aldehyde, which is reacted with the above
described phenol and naphthol to obtain the phenolic resin of the
present invention, include formalin, paraformaldehyde, trioxan,
acetaldehyde, paraldehyde, and propionaldehyde. It is to be
understood that the aldehyde is not limited to the above examples,
and other well-known materials may be suitably used. Any one of, or
any combination of the aldehyde may be used.
[0032] In the present invention, in order to obtain the intended
phenolic resin by reacting the phenol (P) and the naphthol (N) with
the above-described aldehyde (F), it is recommended that the phenol
and the naphthol are reacted with the aldehyde such that the
blending molar ratio: F/(P+N) is in a range of 0.40 to 0.80. By
controlling the blending molar ratio: F/(P+N) so as to be 0.75 or
less, more preferably 0.70 or less, the flexibility can be further
improved. In addition, by controlling the value of F/(P+N) so as to
be 0.40 or more, the intended phenolic resin can be produced with a
sufficient yield, and by controlling the value of F/(P+N) so as to
be 0.80 or less, the strength of the mold which is obtained by
using RCS for shell molding produced by using thus obtained
phenolic resin can be advantageously improved.
[0033] In the present invention, any conventionally known catalyst
such as an acid catalyst is suitably used in the reaction of the
phenol and the naphthol with the aldehyde. Especially, it is
recommended that at least one of a divalent metal salt and an
oxalic acid be used as the catalyst. By using such a specific
catalyst, coefficient of thermal expansion and flexibility can be
further improved, and problems of metal corrosion and the like can
be advantageously solved. Examples of the divalent metal salt
include lead naphthenate, zinc naphthenate, lead acetate, zinc
acetate, zinc borate, lead oxide, and zinc oxide, which are metal
salts having divalent metal element, and a combination of an acidic
catalyst, which is capable of forming the metal salt, and a basic
catalyst. Among the specific catalysts, oxalic acid is preferably
used. Generally, the catalyst including at least one selected from
a group consisting of the divalent metal salts and the oxalic acid
is present in an amount of 0.01 to 5 parts by mass, preferably 0.05
to 3 parts by mass, based on 100 parts by mass of the total of
phenol and naphthol.
[0034] The reaction of phenol, naphthol, and aldehyde in the
presence of the above-described catalyst is conducted in the same
manner as a conventional production method of phenolic resin. Thus
obtained phenolic resin is in a solid or a liquid (for example,
varnish or emulsion) form, and expresses a heat-curing or
-hardening effect when it is heated in the presence or absence of a
hardener or curing catalyst such as hexamethylene tetramine. In the
present invention, a phenolic resin having a number average
molecular weight as measured by gel permeation chromatography (GPC)
in a range of from 400 to 1300 is preferably used. When the number
average molecular weight of the phenolic resin is too small, a mold
to be obtained may not have sufficient strength, because RCS for
shell molding which is coated with the resin composition including
the phenolic resin has poor filling properties in mold-forming. On
the other hand, when the number average molecular weight of the
phenolic resin is too big, a mold to be obtained may not have
sufficient strength, because flowability of resin during heating is
deteriorated.
[0035] In the present invention, the fatty acid amide is added as
an essential component to the above phenolic resin to obtain the
phenolic resin composition for shell molding. Due to the
combination of the phenolic resin and the fatty acid amide, low
thermal expansion properties and improved flexibility can be
advantageously achieved. The ratio of the phenolic resin to the
fatty acid amid is suitably determined depending on required
properties for a mold to be obtained. Generally, 1 to 15 parts by
mass of the fatty acid amide is added based on 100 parts by mass of
the phenolic resin. This is because, when the amount of the fatty
acid amide is too small, advantages and effects to be obtained by
using the fatty acid amide may not be sufficiently exhibited. On
the other hand, when the amount of the fatty acid amide is too big,
the advantages and effects that are of equal worth to the amount of
the fatty acid amide may not be obtained.
[0036] Examples of the fatty acid amide, which is used in
combination with the phenolic resin, include: monoamides such as
saturated fatty acid monoamide and unsaturated fatty acid
monoamide; substituted amides; and bisamides such as saturated
fatty acid bisamide, unsaturated fatty acid bisamide, and aromatic
bisamide. Of those fatty acid amides, the fatty acid bisamide,
especially, the saturated fatty acid bisamide is favorably
used.
[0037] Of the above fatty acid amide, examples of the saturated
fatty acid monoamide include lauramide, myristamide, palmitamide,
stearamide, and behenamide. Examples of the unsaturated fatty acid
monoamide include oleamide, and erucamide. Examples of the
substituted amides include N-stearyl(stearamide),
N-oleyl(stearamide), N-stearyl(erucamide), methylol(stearamide),
and methylol(behenamide). In addition, examples of the saturated
fatty acid bisamide include methylenebis(stearamide),
ethylenebis(stearamide), methylenebis(lauramide),
methylenebis(behenamide), hexamethylenebis(stearamide),
hexamethylenebishydroxyl(stearamide), N,N'-distearyl(adipamide) and
ethylenebis(behenamide). Examples of the unsaturated fatty acid
bisamide include ethylenebis(oleamide), ethylenbis(erucamide),
hexamethylenbis(oleamide), and N,N'-dioleyl(adipamide). Further,
examples of the aromatic bisamide include xylylenebis(stearamide),
xylylenebishydroxy(stearamide), and
N,N'-distearyl(isophthalamide).
[0038] In the present invention, in order to use the phenolic resin
and the fatty acid amide in combination for shell molding, various
conventionally known additives can be added for the purpose of
improving the physical characteristics of the mold, for example.
Examples of the additives include silane coupling agent such as
.gamma.-aminopropyltriethoxysilane and
.gamma.-glycidoxypropyltrimethoxysilane. Generally, such a silane
coupling agent is added in a range of from about 0.01 to about 5
parts by mass, preferably 0.05 to 2.5 parts by mass, based on 100
parts by mass of the phenolic resin.
[0039] In the production of RCS for shell molding according to the
present invention, the above-described phenolic resin composition
for shell molding are kneaded into a fire-refractory particle.
Because an amount of the phenolic resin composition for shell
molding in RCS of the present invention is determined depending on
a kind of resin to be used and strength of the intended mold, for
example, the amount thereof is not necessarily limited. However,
the phenolic resin composition is generally present in a range of
from about 0.2 to about 10 parts by mass, preferably 0.5 to 8 parts
by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts
by mass of the fire-refractory particle.
[0040] In the present invention, the kind of fire-refractory
particle kneaded into the phenolic resin composition for shell
molding is not particularly limited. As the fire-refractory
particle is a basic material for a mold, any known inorganic
particles conventionally used in the shell mold casting may be used
as long as they have fire resistance suitable for casting and
particle diameter suitable for forming a mold (mold-forming). In
addition to a silica sand which is commonly used, examples of the
fire-refractory particle include, special sands such as an olivine
sand, a zircon sand, a chromite sand and an alumina sand, slag
particles such as a ferrochromium slag, a ferronickel slag and a
converter slag, mullite-based sand particles such as Naigai
Cerabeads (commercial name, available from ITOCHU CERATECH CORP.,
JAPAN), and regenerated particles which are obtainable by
recovering and regenerating the above particles after casting. Any
one of, or any combination of the particles may be used.
[0041] In the production of RCS for shell molding, examples of the
production method include, but are not limited to, any conventional
methods such as a dry-hot-coating, a semi-hot-coating, a cold
coating, and a powder-solvent-coating. In the present invention, a
so-called dry-hot-coating is preferably recommended that includes
the steps of kneading a preheated fire-refractory particle and a
resin composition for shell molding in a mixer such as a whirl
mixer or a speed mixer, adding aqueous hexamethylenetetramine
(hardener) solution, converting an aggregated content into
particles by being collapsed by cooling with an air blow, and
adding a calcium stearate (lubricant). The predetermined phenolic
resin and fatty acid amide included in the resin composition for
shell molding of the present invention can not only be melted and
mixed with each other to coat the fire-refractory particle, but
also can independently be used to coat the fire-refractory
particle.
[0042] Further, when making a predetermined shell mold by using the
above-described RCS for shell molding, the process for making or
forming a mold by heating is not particularly limited. Any known
process may be advantageously employed. For example, a casting mold
can be obtained by the steps of: filling a forming die, which has a
cavity corresponding to a shape of an intended shell mold and is
heated to 150 to 300.degree. C., with the above-described RCS by a
gravity-driven method or blowing method; curing the RCS; and
removing the cured (hardened) mold from the forming die. The mold
obtained as above advantageously has the above-mentioned excellent
effect.
EXAMPLES
[0043] To further clarify the present invention, some examples of
the invention will be described. It is to be understood that the
invention is not limited to the details of the illustrated examples
and the foregoing description, but may be embodied with various
changes, modifications and improvements, which may occur to those
skilled in the art without departing from the scope of the
invention.
[0044] Here, "parts" and "%" in the following description refer to
"parts by mass" and "% by mass", respectively, unless otherwise
defined. In addition, characteristics of the produced RCS for shell
molding are measured in accordance with the following test
methods.
[0045] --Evaluation of Flexibility of Mold--
[0046] Initially, for the evaluation of flexibility of mold, a
piece of mold (120 mm.times.40 mm.times.5 mm) made of each kind of
RCS was prepared under a cure condition: at 250.degree. C. for 40
seconds. Then, the piece of mold was left until it was cooled to a
room temperature.
[0047] Subsequently, thus obtained piece of mold was set on a
support as shown in FIG. 1, and an exothermic stick (Erema
exothermic stick) was gradually heated from 200.degree. C. to
800.degree. C. Meanwhile, a laser displacement gauge was positioned
10 mm away from an end portion of the piece of mold, and data
thereof was directly entered into a computer. Behaviors with
respect to the displacement were as follows: at first the piece of
mold was warped due to an expansion behavior caused by the heating
of the piece of mold; then the piece was started to be bent; and
finally, the piece of mold was fractured almost at the center
thereof, i.e., at the position heated by the exothermic stick. The
term "flexibility" used herein is expressed by the maximum
deflection obtained before the piece of mold was fractured. The
higher value of the flexibility indicates that the mold is more
easily deformed, which means that the mold is flexible. This
measurement was conducted in consideration of measurement cycle
such that the next measurement of a piece of mold starts when the
temperature of the exothermic stick is reached around 200.degree.
C.
[0048] --Evaluation of Coefficient of Thermal Expansion--
[0049] Evaluation of coefficient of thermal expansion was conducted
in accordance with a test method of rapid coefficient of thermal
expansion specified in JACT test method M-2, test method of
coefficient of thermal expansion. A test piece (diameter of 28.3
mm.times.length of 51 mm, cut into about 1/4 of circumference)
produced by heating a piece of mold at a temperature of 280.degree.
C. for 120 seconds was placed in a high-temperature casting sand
tester controlled at 1000.degree. C. and was taken out from it
after 1 minute. A coefficient of thermal expansion was calculated
by the lengths of the test piece before the heating and after the
heating according to the following formula.
A coefficient of thermal expansion(%)={length of test piece(after
heating-before heating).times.100}/(length of test piece before
heating)
Resin Production Example 1
[0050] To a reaction vessel provided with a thermometer, a stirring
device, and a condenser, 8000 parts of phenol, 2000 parts of
1-naphthol, 4106 parts of 47% formalin, and 30 parts of oxalic acid
were charged. Subsequently, a temperature in the reaction vessel
was gradually raised to a reflux temperature and the mixture was
subjected to a reaction under reflux condition for 90 minutes.
Further, the mixture was dehydrated under ordinary pressure and
heated under reduced pressure until the temperature reached
180.degree. C. Accordingly, unreacted phenol was removed and
phenolic resin A was obtained.
Resin Production Example 2
[0051] Phenolic resin B was obtained in the same way as Resin
Production Example 1 with the exception that 8000 parts of phenol,
2000 parts of 1-naphthol, 4865 parts of 47% formalin and 30 parts
of oxalic acid were charged.
Resin Production Example 3
[0052] Phenolic resin C was obtained in the same way as Resin
Production Example 1 with the exception that 8000 parts of phenol,
2000 parts of 1-naphthol, 3159 parts of 47% formalin and 30 parts
of oxalic acid were charged.
Resin Production Example 4
[0053] Phenolic resin D was obtained in the same way as Resin
Production Example 1 with the exception that 9000 parts of phenol,
1000 parts of 1-naphthol, 4260 parts of 47% formalin and 30 parts
of oxalic acid were charged.
Resin Production Example 5
[0054] Phenolic resin E was obtained in the same way as Resin
Production Example 1 with the exception that 6000 parts of phenol,
4000 parts of 1-naphthol, 3799 parts of 47% formalin and 15 parts
of oxalic acid were charged.
Resin Production Example 6
[0055] Phenolic resin F was obtained in the same way as Resin
Production Example 1 with the exception that 8000 parts of phenol,
2000 parts of 2-naphthol, 4106 parts of 47% formalin and 30 parts
of oxalic acid were charged.
Resin Production Example 7
[0056] Phenolic resin G was obtained in the same way as Resin
Production Example 1 with the exception that 2000 parts of phenol,
8000 parts of bisphenol A (BPA), 2339 parts of 47% formalin and 30
parts of oxalic acid were charged.
Example 1
[0057] 50 parts of ethylenebis(stearamide) and 10 parts of silane
coupling agent (3-aminopropyltriethoxysilane) were mixed into 1000
parts of phenolic resin A by heating and melting to obtain Resin
composition 1.
Example 2
[0058] Resin composition 2 was obtained in the same way as Example
1 with the exception that the amount of ethylenebis(stearamide) was
changed to 120 parts.
Example 3
[0059] Resin composition 3 was obtained in the same way as Example
1 with the exception that the amount of ethylenebis(stearamide) was
changed to 15 parts.
Example 4
[0060] Resin composition 4 was obtained in the same way as Example
1 with the exception that methylenebis(stearamide) was used instead
of ethylenebis(stearamide).
Example 5
[0061] Resin composition 5 was obtained in the same way as Example
1 with the exception that ethylenebis(behenamide) was used instead
of ethylenebis(stearamide).
Example 6
[0062] Resin composition 6 was obtained in the same way as Example
1 with the exception that ethylenbis(erucamide) was used instead of
ethylenebis(stearamide)
Example 7
[0063] Resin composition 7 was obtained in the same way as Example
1 with the exception that stearamide was used instead of
ethylenebis(stearamide).
Example 8
[0064] Resin composition 8 was obtained in the same way as Example
1 with the exception that phenolic resin B was used instead of
phenolic resin A.
Example 9
[0065] Resin composition 9 was obtained in the same way as Example
1 with the exception that phenolic resin C was used instead of
phenolic resin A.
Example 10
[0066] Resin composition 10 was obtained in the same way as Example
1 with the exception that phenolic resin D was used instead of
phenolic resin A.
Example 11
[0067] Resin composition 11 was obtained in the same way as Example
1 with the exception that phenolic resin E was used instead of
phenolic resin A.
Example 12
[0068] Resin composition 12 was obtained in the same way as Example
1 with the exception that phenolic resin F was used instead of
phenolic resin A.
Comparative Example 1
[0069] Resin composition 13 was obtained in the same way as Example
1 with the exception that phenolic resin G was used instead of
phenolic resin A.
Comparative Example 2
[0070] Resin composition 14 was obtained in the same way as Example
1 with the exception that no fatty acid amide was added to the
phenolic resin A.
Comparative Example 3
[0071] Resin composition 15 was obtained in the same way as Example
1 with the exception that no fatty acid amide was added to the
phenolic resin D.
Comparative Example 4
[0072] Resin composition 16 was obtained in the same way as Example
1 with the exception that no fatty acid amide was added to the
phenolic resin E.
Comparative Example 5
[0073] Resin composition 17 was obtained in the same way as Example
1 with the exception that no fatty acid amide was added to the
phenolic resin F.
Production Example 1 of RCS
[0074] To a laboratory whirl mixer, 7000 parts of fire-refractory
particle (regenerated silica sand) heated to 130 to 140.degree. C.
and 105 parts of the phenolic resin composition obtained in each of
the above Examples 1 to 12 and Comparative Examples 1 to 5, were
added and kneaded for 60 seconds. Then, after 23 parts of
hexamethylenetetramine dissolved in 105 parts of water was added
thereto and cooled by an air blow, 7 parts of calcium stearate was
added. As a result, RCS for shell molding (Samples 1 to 17)
produced by using each of the resin compositions of the above
Examples and Comparative Examples were obtained.
Production Example 2 of RCS
[0075] To a laboratory whirl mixer, 7000 parts of fire-refractory
particle (regenerated silica sand) heated to 130 to 140.degree. C.,
and 105 parts of the above phenolic resin A and 5.25 parts of
ethylenebis(stearamide), which constitute Resin composition 18,
were each independently added and kneaded for 60 seconds. Then,
after 23 parts of hexamethylenetetramine dissolved in 105 parts of
water was added thereto and cooled by an air blow, 7 parts of
calcium stearate was added. As a result, RCS for shell molding
(Sample 18) was obtained.
EVALUATION
[0076] In accordance with the test method described above, each RCS
(Samples 1 to 18) obtained as above was subjected to the
measurement of flexibility and coefficient of thermal expansion of
mold. The results thereof are shown in the following Table 1 and
Table 2, together with the production condition of phenolic
resin.
TABLE-US-00001 TABLE 1 RCS Sample 1 Sample 2 Sample 3 Sample 4
Sample 5 Sample 6 Sample 7 Sample 8 Sample 9 Resin composition 1 2
3 4 5 6 7 8 9 Components Phenolic resin A A A A A A A B C Phenol
[%] 80 80 80 80 80 80 80 80 80 1-naphthol [%] 20 20 20 20 20 20 20
20 20 2-naphthol [%] -- -- -- -- -- -- -- -- -- BPA [%] -- -- -- --
-- -- -- -- -- Molar Ratio 0.65 0.65 0.65 0.65 0.65 0.65 0.65 0.77
0.50 F/(P + N) Fatty acid amide Ethylenebis Methyl- Ethylenebis
Ethylenebis Stearamide Ethylenebis (stearamide) enebis (behen-
(erucamide) (stearamide) (stearamide) amide) Amount [part] 5 12 1.5
5 5 5 5 5 5 (based on 100 parts by mass of resin) Mold coefficient
0.73 0.72 0.75 0.74 0.72 0.72 0.71 0.69 0.77 characteristics of
thermal expansion [%] flexibility 7.2 10.0 5.8 7.5 7.1 7.4 7.8 5.4
9.8 [mm]
TABLE-US-00002 TABLE 2 RCS Sample 10 Sample 11 Sample 12 Sample 13
Sample 14 Sample 15 Sample 16 Sample 17 Sample 18 Resin Composition
10 11 12 13 14 15 16 17 18 Components Phenolic resin D E F G A D E
F A Phenol [%] 90 60 80 20 80 90 60 80 80 1-naphthol [%] 10 40 --
-- 20 10 40 -- 20 2-naphthol [%] -- -- 20 -- -- -- -- 20 -- BPA [%]
-- -- -- 80 -- -- -- -- -- Molar Ratio 0.65 0.65 0.65 0.65 0.65
0.65 0.65 0.65 0.65 F/(P + N) Fatty acid amide Ethylenebis
(stearamide) -- Ethylenebis (stearamide) Amount [parts] 5 5 5 5 0 0
0 0 5 (based on 100 parts by mass of resin) Mold coefficient of
thermal 0.75 0.71 0.76 0.73 0.76 0.77 0.74 0.78 0.74
characteristics expansion [%] flexibility [mm] 6.3 10.5 8.4 3.9 4
2.9 3.4 3.1 7.0
[0077] As apparent from the results shown in Table 1 and Table 2,
every RCS (Samples 1 to 12) obtained by using the resin
compositions 1 to 12 which include phenolic resins A to F of Resin
production examples 1 to 6 and a predetermined fatty acid amide,
which are in accordance with the present invention, has low
coefficient of thermal expansion and high flexibility. On the other
hand, RCS (Sample 13) obtained by using the phenolic resin G of
Resin production example 7, in which phenol and bisphenol A was
used as the phenol components, has low flexibility. Further, RCS
(Samples 14 to 17) obtained by using the resin compositions 14 to
17, in which no fatty acid amide was added to phenolic resin A, D,
E and F, have low flexibility. Furthermore, RCS (Sample 18)
obtained by independently adding the phenolic resin A and the fatty
acid amide, which constitute a resin composition, into a
fire-refractory particle has excellent low coefficient of thermal
expansion and excellent flexibility.
* * * * *