U.S. patent application number 13/395396 was filed with the patent office on 2012-08-30 for binder coated refractories, casting mold using the same, and method of manufacturing casting mold using the same.
Invention is credited to Isamu Ide, Shinji Nishida, Toru Seki.
Application Number | 20120217373 13/395396 |
Document ID | / |
Family ID | 43732464 |
Filed Date | 2012-08-30 |
United States Patent
Application |
20120217373 |
Kind Code |
A1 |
Ide; Isamu ; et al. |
August 30, 2012 |
BINDER COATED REFRACTORIES, CASTING MOLD USING THE SAME, AND METHOD
OF MANUFACTURING CASTING MOLD USING THE SAME
Abstract
The binder coated refractories comprises the refractory
aggregates and the solid-form coating layer which comprises the
sugar group as the binder and which is provided to the surface of
the refractory aggregates. According to this, the sugar group is
used as the binder for bonding the refractory aggregates. Further,
even if the sugar group is thermally decomposed, the sugar group
emits the carbon dioxide and the water. Therefore, there is little
likelihood of emitting the harmful gas. Therefore, it is possible
to reduce the environmental pollution. Further, the sugar group is
thermally decomposed easily. Therefore, it is possible to
manufacture the casting mold having the good breaking property.
Inventors: |
Ide; Isamu; (Sakai-shi,
JP) ; Seki; Toru; (Sakai-shi, JP) ; Nishida;
Shinji; (Osaka, JP) |
Family ID: |
43732464 |
Appl. No.: |
13/395396 |
Filed: |
September 8, 2010 |
PCT Filed: |
September 8, 2010 |
PCT NO: |
PCT/JP2010/065428 |
371 Date: |
May 16, 2012 |
Current U.S.
Class: |
249/117 ;
164/525; 524/48 |
Current CPC
Class: |
B22C 1/2253 20130101;
B22C 1/26 20130101; C09D 103/02 20130101; B22C 9/02 20130101; B22C
9/12 20130101 |
Class at
Publication: |
249/117 ;
164/525; 524/48 |
International
Class: |
B22C 9/00 20060101
B22C009/00; C08L 3/02 20060101 C08L003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2009 |
JP |
2009-209123 |
Claims
1. Binder coated refractories each comprising: a refractory
aggregate, wherein each of said refractory aggregate is coated with
a coating layer which has a sugar group defined as a binder and
which is a solid form.
2. The binder coated refractories a set forth in claim 1, wherein
said coating layer has the binder which comprises the sugar group
in addition to a thermosetting resin.
3. The binder coated refractories as set forth in claim 2, wherein
said thermosetting resin is a phenolic resin.
4. The binder coated refractories as set forth in claim 1, wherein
said coating layer further comprises a carboxylic acid as a curing
agent of the sugar group.
5. The binder coated refractories as set forth in claim 1, wherein
said refractory aggregates are selected from at least one of silica
sand, pit sand, alumina sand, olivine sand, chromite sand, zircon
sand, mullite sand, and artificial sand.
6. The binder coated refractories as set forth in claim 2, wherein
said thermosetting resin is configured to coat a surface of each
said refractory aggregate, and said sugar group is configured to
coat a surface of each said thermosetting resin.
7. The binder coated refractories as set forth in claim 1, wherein
a proportion of the binder in the refractory aggregates is from 0.5
percents by mass or more to 5 percents by mass or less.
8. The binder coated refractories as set forth in claim 2, wherein
a proportion of said thermosetting resin in a total amount of said
binder is more than 0 percents by mass and 80 percents by mass or
less.
9. The binder coated refractories as set forth in claim 8, wherein
a proportion of said thermosetting resin in a total amount of said
binder is more than 0 percents by mass and 50 percents by mass or
less.
10. The binder coated refractories as set forth in claim 1, wherein
said sugar group is located in an outermost of said coating
layer.
11. A casting mold comprising said binder coated refractories as
set forth in claim 1, wherein said binder coated refractories are
bonded to each other with the binder in the coating layer.
12. A method of manufacturing a casting mold using the binder
coated refractories as set forth in claim 1, said method comprises:
a step of filling a mixture of the binder coated refractories and
the water in a casting flask, and a step of freezing the water in
the mixture.
13. The method of manufacturing a casting mold using binder coated
refractories each comprising a refractory aggregate and a coating
layer, each said refractory aggregate having fire resistance, each
said coating layer being configured to coat a surface of each the
refractory aggregates, said coating layer having a binder which has
a sugar group, each said coating layer having a solid form, said
method comprising: a filling step of filling the binder coated
refractories in a casting flask; a solidifying-hardening step of
supplying water vapor to an inside of said casting flask to change
said sugar groups into said sugar groups having sticky paste
condition, then, heating said binder coated refractories to
solidify-harden said binders in said coating layers, whereby said
binder coated refractories are bonded with each other.
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. The method of manufacturing the casting mold as set forth in
claim 13, wherein said water vapor is a saturated water vapor, said
method comprising steps of: supplying moisture into the casting
flask filled with said binder coated refractories to provide wet to
the binder, then, supplying the superheated steam into the casting
flask to heat the binder coated refractories and to remove the
moisture of said binder and increase the temperature of the binder
coated refractories by the latent heat of the condensation of the
superheated steam, whereby the binders of the coating layers are
solidified-hardened and the binder coated refractories are bonded
with each other.
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. (canceled)
29. (canceled)
30. A method of manufacturing a casting mold using binder coated
refractories which comprises refractory aggregates and coating
layers, said refractory aggregates having fire resistance, each
said coating layer coating a surface of each said refractory
aggregate, each said coating layer comprising a binder having a
sugar group, each said coating layer having a solid form, said
method comprising: a filling step of filling said binder coated
refractories to a casting flask, a solidifying-hardening step of
supplying moisture into the casting flask to provide a wet to said
binder and to provide said sugar group with sticky paste condition,
then, supplying a superheated steam into said casting flask cause
increasing of the temperature of said binder coated refractories,
drying said binder coated refractories and solidifying-hardening
said binder of said coating layer by increasing the temperature of
said binder coated refractories to bond said binder coated
refractories with each other.
Description
TECHNICAL FIELD
[0001] This invention relates to binder coated refractories used
for manufacturing of a casting mold, a casting mold using the
binder coated refractories, and a method of manufacturing the
casting mold using the binder coated refractories.
BACKGROUND ART
[0002] Conventionally, there are a plurality of methods of
manufacturing the casting mold. As to one of the method of
manufacturing the casting mold, the shell molding method is well
known. The shell molding method is a method for manufacturing the
casting mold by bonding the refractory aggregates by the binder.
The refractory aggregates are exemplified by silica sand. The shell
molding method is realized as an effective method for producing the
casting mold having a good dimensional accuracy. According to this
reason, the shell molding method is frequently used when producing
the casting mold.
[0003] As to the binder for the shell molding method, the
thermosetting resin such as phenol resin is generally used. The
refractory aggregates are mixed with the thermosetting resin to
produce the resin coated sand. The resin coated sand comprises the
refractory aggregates each are coated at its surface with the
thermosetting resin. According to filling the metallic mold with
the resin coated sand and then melting-curing the thermosetting
resin, the casting mold is produced.
[0004] The resin coated sand is granulated substance which itself
is dry. In addition, the resin coated sand has a good flowability.
Therefore, it is possible to easily fill the metallic mold with the
resin coated sand. In addition, the resin coated sand has a good
deterioration resistance when handling is made under air
atmosphere. According to this, the shell molding method using the
resin coated sand is well-used for manufacturing the mold for the
automobile.
[0005] In the resin coated sand, as to the thermosetting resin
binder which coats the surface of the refractory aggregate, as
explained above, the phenol resin is conventionally used.
Especially, a novolac-type phenolic resin is well-used as the
thermosetting resin binder. The novolac-type phenolic resin has a
thermoplastic property. The novolac-type phenolic resin is not
cured when heated. Therefore, in using the novolac-type phenolic
resin, a curing agent is typically mixed with the novolac-type
phenolic resin. The curing agent is exemplified by the
hexamethylenetetramine. (Refer to Patent Literature 1 hereinafter
explained)
[0006] When the resin coated sand having the novolac-type phenolic
resin as the binder is filled in the heated metallic mold having a
temperature of, for example, 250 degrees Celsius to 350 degrees
Celsius, the heat in the metallic mold is transferred to the
hexamethylenetetramine. Then, the hexamethylenetetramine is
decomposed into the formaldehyde and the ammonia. A most part of
the formaldehyde reacts with the novolac-type phenolic resin.
According to this reaction, the phenol resin is cured to have a
non-solubility.
[0007] However, "a part of the formaldehyde which is not reacted"
and "most of ammonia" are volatilized into the atmosphere during
and after producing the casting mold. The formaldehyde and the
ammonia cause the environmental pollution. When the resol-type
phenolic resin is used as the phenol resin, it is possible to
reduce the above problem. However, also in using the resol-type
phenolic resin, the some formaldehyde is unreacted and is
volatilized into the atmosphere. Therefore, the resol-type phenolic
resin has the above problem, too.
[0008] In addition, when the resin coated sand with the phenol
resin as the binder is used in manufacturing of the molding, the
molten metal is poured into the casting mold. However, when pouring
the molten metal into the casting mold, the heat in the molten
metal degrades the phenol resin. Consequently, the gases such as
phenol, xylenol, toluene, benzene, and methane are released. This
also causes the problem of pollution.
[0009] Furthermore, the phenol resin has a good heat resistance
property. In addition, the phenol resin has a large amount of
residual carbon. Therefore, even if pouring the molten metal into
the casting mold to form the cast metal is performed, it is
difficult to break the casting mold by the heat of the molten
metal. Owing to this, in order to demold the cast metal from the
casting mold, there is a need to apply the force to the casting
mold. In addition, there is a need to apply the high-temperature
heat over a long period to decompose the phenol resin. That is,
demolding the cast metal from the casting mold requires the
additional work.
CITATION LIST
[0010] PATENT LITERATURE JAPANESE PATENT APPLICATION PUBLICATION
No. 2002-346691A
SUMMARY OF INVENTION
Technical Problem
[0011] This invention is produced in view of the above. An object
of this invention is to produce the binder coated refractories for
reduce the generation of the gas which pollute the environment. In
addition, an object of this invention is to produce the casting
mold being easily broken when demolding the cast metal. In
addition, an object of this invention is to produce the method of
manufacturing the casting mold which is reduced the generation of
the gas which pollutes the environment and which has a good
breakage property.
Problem to Solve
[0012] This invention discloses the binder coated refractories each
comprises the refractory aggregate. Further, each the refractory
aggregate is coated at its surface with the coating layer. The
coating layer comprises the binder having the sugar group. The
coating layer has a solid form.
[0013] According to this invention, the sugar group acts as the
binder to bond the refractory aggregates with each other. In
addition, if the sugar group is thermally decomposed, the sugar
group emits the carbon dioxide gas and the water. Therefore, it is
possible to reduce the emission of the harmful gas and reduce the
environmental pollution. Further, the sugar group has a property of
being thermally decomposed easily. Therefore, it is possible to
produce the casting mold having a good breaking property with using
the binder coated refractories.
[0014] Further, the coating layer preferably comprises the binder
which has a thermosetting resin in addition to the sugar group.
[0015] According to this, in addition to the bonding of the sugar
group, the bonding between the refractory aggregates is also
established by the thermosetting resin. Therefore, this
configuration makes it possible to improve the strength of the
bonding of the refractory aggregates.
[0016] Furthermore, the thermosetting resin preferably comprises
the phenol resin.
[0017] According to the phenol resin, the bonding strength of the
refractory aggregates is improved.
[0018] In addition, the coating layer preferably comprise the
carboxylic acid as a curing agent of the sugar group.
[0019] Furthermore, an amount of the carboxylic acid with respect
to 100 part by mass of the sugar group is from 0.1 parts by mass or
more to 10 parts by mass or less.
[0020] According to this, the carboxylic acid cross-links and cures
the sugar group. Therefore, it is possible to improve the bonding
strength of the refractory aggregates.
[0021] Furthermore, the casting mold of this invention is made of
the binder coated refractories which are bonded with each other by
the binder of the coating layer.
[0022] According to this, the sugar group acts as the binder
between the refractory aggregates to form the casting mold. In
addition, if the sugar group is thermally decomposed, the sugar
group emits the carbon dioxide and the water. In other words, the
sugar group does not emit the harmful gas. Therefore, there is
little likelihood that the sugar group emits something to pollute
the environment. In addition, the sugar group is thermally
decomposed by the sugar group, easily. Therefore, using the binder
coated refractories of the above makes it possible to produce the
casting mold having the good breaking property.
[0023] In addition, the method of manufacturing the casting mold
comprises the filling step and the solidifying-hardening step. In
the filling step, filling the binder coated refractories in the
casting flask is performed. In the solidifying-hardening step,
supplying the water vapor into the casting flask and heating the
binder coated refractories to solidify-harden the binder of the
coating layer are performed.
[0024] The water vapor has a latent heat of the condensation.
Therefore, according to supplying the water vapor into the casting
flask filled with the binder coated refractories, the latent heat
is transferred from the water vapor to the binder coated refractory
when the binder coated refractories are exposed to the water vapor.
In other words, there is no need to preheat the casting flask to
high temperature. Therefore, this method makes it possible to
manufacture the casting mold stably at short times. Further, even
if the harmful gas is generated, the harmful gas is absorbed to the
condensation water of the water vapor. Therefore, it is possible to
decrease the environmental pollution.
[0025] Furthermore, this invention comprises the step of supplying
the water vapor into the casting flask to "provide the sugar group
in the binder of the coating layer with the sticky paste condition"
and to "increase the temperature of the binder by the latent heat
of the condensation of the water vapor to solidify-harden the
binder".
[0026] When the water vapor is supplied into the casting flask, the
binder coated refractories are exposed to the water vapor.
Consequently, the heat of the water vapor is transmitted to the
binder coated refractory. Then, the condensation water is
developed. According to the condensation water, the sugar group is
swelled to have the sticky paste condition. The sugar group having
the sticky paste condition bonds the refractory aggregates with
each other. Further, by the latent heat of the condensation of the
water vapor, the binder coated refractories is increased their
temperature or more for solidify-harden the binder. Therefore, it
is possible to manufacture the casting mold having a high
strength.
[0027] In addition, this invention comprises the step of supplying
the water vapor into the casting flask to increase the temperature
of the binder coated refractory by the latent heat of the
condensation of the water vapor and supplying the heated gas into
the casting flask to evaporate the condensation water in the
casting flask and to solidify-harden the binder of the binder
coated refractories.
[0028] By supplying the water vapor into the casting flask filled
with the binder coated refractories, the latent heat of the
condensation of the water vapor rapidly increase the temperature of
the binder coated refractory to about 100 degrees C. Then, by
supplying the heated gas into the casting flask, the condensation
water is rapidly evaporated by the gas having a little moisture. In
addition, supplying the heated gas makes it possible to increase
the condensation water to 100 degrees C. or more at short times.
Therefore, this configuration makes it possible to raise the rate
of increase of the temperature in the casting flask to the
temperature or more for solidifying-hardening the binder of the
binder coated refractories. Therefore, this configuration makes it
possible to manufacture the casting mold having the high strength
at short times.
[0029] Furthermore, the method of manufacturing the casting mold of
this invention comprises a step of adding the water to the binder
coated refractories to prepare the mixture of them, filling the
mixture in the casting flask, and freezing the water.
[0030] With this method, by the water freezing, the refractory
aggregates are bonded. Furthermore, the water changes the sugar
group of the coating layer of the binder coated refractory into the
sticky paste condition. The refractory aggregates are bonded with
the sugar group having the sticky paste condition. Therefore, this
configuration makes it possible to manufacture the casting mold
having the high strength.
[0031] In addition, this invention discloses another method of
manufacturing the casting mold. The method of manufacturing the
casting mold disclosed in this invention uses the binder coated
refractories. Each the binder coated refractory comprises the
refractory aggregate and the coating layer. The refractory
aggregate has the fire resistance. The coating layer coats the
surface of the refractory aggregate. The coating layer has a solid
form. The coating layer has a sugar group as a binder. The method
of manufacturing the casting mold comprises a filling step and a
solidifying-hardening step. In the filling step, filling the binder
coated refractories into the casting flask is performed. In the
solidifying-hardening step, supplying the water vapor into the
casting flask to change the solid form of the sugar group into the
sticky paste condition of the sugar group is performed. Subsequent
to the step of supplying the water vapor, heating the binder coated
refractories to solidify-harden the binders of the coating layers.
Consequently, the binder coated refractories are bonded with each
other.
[0032] The coating layer preferably comprises the thermosetting
resin. In addition, the thermosetting resin preferably comprises
the phenol resin.
[0033] In this case, the casting mold made of the binder coated
refractories is capable of keeping its form under high
temperature.
[0034] The coating layer preferably comprises the carboxylic
acid.
[0035] In heating step, heating the binder coated refractories
preferably comprises the step of increasing the temperature of the
sticky-paste-condition sugar group by the latent heat of the water
vapor to solidify-harden the binder having the sticky paste
condition.
[0036] Further, the step of heating the binder coated refractories
preferably comprises a first heating step and evaporating step. In
the first heating step, increasing the temperature of the sugar
group having the sticky paste condition by the latent heat of the
condensation of the water vapor is performed. In the evaporating
step, supplying the heated gas into the casting flask to evaporate
the condensation water in the casting flask and to heat the binder
to the temperature or more which is sufficient to solidify-harden
the binder.
[0037] The heated gas is preferably the heated air.
[0038] The heated gas is also preferably the mixture gas comprises
the water vapor and the gas mixed with each other.
[0039] Furthermore, the water vapor is preferably a superheated
steam.
[0040] The refractory aggregates is preferably selected from at
least one of silica sand, pit sand, alumina sand, olivine sand,
chromite sand, zircon sand, mullite sand, and the artificial
sand.
[0041] It is preferred that the sugar group is at east one of
monomeric sugar, oligosaccharides and polysaccharides.
[0042] The thermosetting resin preferably coats the surface of the
refractory aggregates. In addition, the sugar group preferably
coats the surface of the thermosetting resin.
[0043] The method of manufacturing the casting mold preferably
comprises the coating step. The coating step is performed before
the filling step of filling the binder coated refractory to the
casting flask. The coating step comprises "a step of heating the
refractory aggregates", "a step of adding the thermosetting resin
to the heated refractory aggregates", "a step of mixing the
thermosetting resin and the heated refractory aggregates to obtain
the mixture of the refractory aggregates and the thermosetting
resin", "a step of adding the sugar group dissolved in or dispersed
into the water to the mixture", "a step of mixing the mixture with
the sugar group", and "a step of drying the mixture and the sugar
group".
[0044] Preferably, the proportion of an amount of the binder with
respect to total weight of the refractory aggregates is from "0.5
percents by mass or more" to "5.0 percents by mass or less".
[0045] Preferably, the proportion of an amount of the thermosetting
resin with respect to total amount of the binder is from "0
percents by mass or more" to "80 percents by mass or less". More
preferably, the proportion of an amount of the thermosetting resin
with respect to total amount of the binder is from "0 percents by
mass or more" to "50 percents by mass or less".
[0046] Further, this invention discloses the method of
manufacturing the casting mold. The method of manufacturing the
casting mold uses the binder coated refractories. Each the binder
coated refractories comprises the refractory aggregate and the
coating layer. Each the refractory aggregate has the fire
resistance. Each the refractory aggregate is coated with the
coating layer. The coating layer comprises the binder having the
sugar group. The coating layer has the solid form. The method of
manufacturing the casting mold comprises a filling step and a
solidifying-hardening step. In the filling step, filling the binder
coated refractories into the casting flask is performed. In the
solidifying-hardening step, supplying the wet into the casting
flask to "provide the wet to the binder" and "change the solid-form
sugar group into sticky-paste-condition sugar group" is performed.
The, the step of supplying the superheated steam into the casting
flask to heat the binder coated refractories is performed.
Consequently, the temperature of the binder coated refractories is
increased. According to increasing the temperature of the binder
coated refractories, "drying the binder coated refractories" and
"solidifying-hardening--the binders in the coating layers" are
performed. Consequently, the binder coated refractories are bonded
with each other.
Advantageous Effect of the Invention
[0047] The binder coated refractories of this invention have the
sugar group as the binder to bond the refractory aggregates with
each other. Even if the sugar group is thermally decomposed, the
sugar group emits the carbon dioxide and the water. In other words,
the sugar group emits little harmful gas. Therefore, there is
little likelihood of causing the environmental pollution. Further,
the sugar group is thermally decomposed, easily. Therefore, it is
possible to produce the casting mold having a good breaking
property with using the binder coated refractories.
[0048] Furthermore, according to the method of manufacturing the
casting mold of this invention, it is possible to manufacture the
casting mold with little environmental pollution.
BRIEF EXPLANATION OF DRAWINGS
[0049] FIG. 1 A shows a cross sectional view of one example of the
manufacturing of the casting mold of this invention.
[0050] FIG. 1 B shows a cross sectional view of one example of the
manufacturing of the casting mold of this invention.
DESCRIPTION OF EMBODIMENTS
[0051] Hereinafter an explanation of this embodiment is made.
[0052] The refractory aggregates in this invention are not limited,
in particular. However, the refractory aggregates are exemplified
by silica sand, pit sand, alumina sand, olivine sand, chromite
sand, zircon sand, mullite sand, and artificial sand. In addition,
it is possible to use only one kind of them as the refractory
aggregates. In addition, it is also possible to use a plurality
kinds of them which are mixed with each other as the refractory
aggregates. In addition, the artificial sand is exemplified by the
sand which is artificially produced and which has calcia, magnesia,
and alumina. In addition, the artificial sand is exemplified by the
sand which is artificially produced by blasting the rocks. That is,
the artificial sand may be realized by the sand which is
artificially produced and which is typically used.
[0053] The binder coated refractories in this invention is produced
by coating the surface of each one of the grains of the refractory
aggregates with the coating layer having the binder. In addition,
in this invention, the sugar group is used as the binder. The sugar
group is exemplified by the monomeric sugar, oligosaccharides and
polysaccharides. In addition, it is possible to use only one kind
of them as the binder. In addition, it is possible to use a
plurality kinds of them as the binder, parallely.
[0054] In this invention, the monomeric sugar used in this
invention is not limited especially. However, the monomeric sugar
is exemplified by the glucose (grape sugar), fructose (fruit
sugar), and galactose.
[0055] In addition, the oligosaccharides are exemplified by
two-sugar such as maltose (malt sugar), sucrose, lactose (milk
sugar), and cellobiose.
[0056] Furthermore, the polysaccharides is exemplified by starch
sugar, dextrin, xanthan gum, curdlan, pullulan, cycloamylose,
chitin, cellulose, and starch. It is possible to use only one kind
of them. In addition, it is possible to use a plurality kinds of
them in parallel. In addition, the starch is exemplified by raw
starch and modified starch. Specifically, the starch is exemplified
by the raw starch such as potato starch, cornstarch, sweet potato
starch, tapioca starch, sago starch, rice starch, amaranth starch.
The starch is exemplified by the modified starch that the raw
starch explained above is modified. (roasted dextrin, enzyme
denaturation dextrin, acid treating starch, oxidized starch,
dialdehyde starch, etherified starch (carboxymethyl starch,
hydroxyalkyl starch, cation starch, methylol starch), esterified
starch, (acetic acid starch, starch phosphate, succinic acid
starch, octenyl succinic acid starch, maleic acid starch, highly
fatty acid starch), bridge starch, craft starch, and heat and
humidity treating starch. Especially, the starch having low
molecular compound such as roasted dextrin, enzyme denaturation
dextrin, acid treating starch, oxidized starch is preferred. In
addition, the starch having low viscosity such as bridge starch is
also preferred.
[0057] In addition, it is possible to use the seed powder of the
grain having the sugar group as the binder. The seed powder of the
grain having the sugar group is exemplified by the wheat flower,
the rice flour, and the corn flour.
[0058] The coating layer may have a carboxylic acid as the curing
agent for the sugar group, especially for polysaccharide. Although
the carboxylic acid is not limited, the carboxylic acid is
exemplified by the oxalic acid, maleic acid, succinic acid, citric
acid, butanetetradicarboxylic acid, methyl vinyl ether-maleic acid
anhydride copolymer. In addition, with regard to the contained
amount of the carboxylic acid in the coating layer, it is preferred
that an amount of carboxylic acid is from 0.1 parts by mass to 10
parts by mass with respect to 100 parts by mass of sugar group. In
addition, it is preferred that the carboxylic acid is mixed with
water prior to mixing the carboxylic acid with the sugar group.
Consequently, the carboxylic acid is enhanced its efficiency of the
curing agent.
[0059] In this invention, the coating layer includes the binder
which has the sugar group. However, the coating layer may include
the binder which has the sugar group and the thermosetting resin in
combination in parallel. The contained amount of the thermosetting
resin in the coating layer is preferably set to be equal to or less
than 80 percents by mass with respect to the total amount of the
sugar group and the thermosetting resin. In addition, the contained
amount of the thermosetting resin in the coating layer is more
preferably set to be equal to or less than 50 percents by mass with
respect to the total amount of the sugar group and the
thermosetting resin. Although the thermosetting resin is not
limited in particular, the thermosetting resin is exemplified by
the resol-type phenolic resin and the novolac-type phenolic resin.
In addition, it is possible to only use the resol-type phenolic
resin or to only use the novolac-type phenolic resin. In addition,
it is possible to use the resol-type phenolic resin and the
novolac-type phenolic resin in combination with each other.
Furthermore, it is possible to use the binder which has the sugar
group and the phenol resin which are reacted in advance.
[0060] In addition, in order to improve the flowability of the
binder coated refractories, the coating layer may further include
the lubricant. As to the lubricant, the lubricant of aliphatic
hydrocarbon type, the lubricant of fatty amides type, lubricant of
metallic soap, lubricant of fatty acid ester, and composition
lubricant may be used as the lubricant. The lubricant of aliphatic
hydrocarbon type is exemplified by the paraffin wax and the
carnauba wax. The lubricant of fatty amides type is exemplified by
the highly fatty alcohol, the ethylenebis stearic acid amide, and
stearic amide. In addition, the lubricant of metallic soap is
especially preferred to the lubricant. As to the metallic soap,
calcium stearate, barium stearate, zinc stearate, aluminum
stearate, magnesium stearate, and the mixture of them are
exemplified.
[0061] The grains of the refractory aggregate are mixed with the
sugar group. In addition, as necessary, the carboxylic acid, the
thermosetting resin such as phenol resins, the reactant of the
sugar group and the phenol resins, and the lubricant are mixed with
the refractory aggregate and the sugar group. In this manner, each
the refractory aggregate is coated with the coating layer which
includes the binder having the sugar group as the main component.
Consequently, the binder coated refractories in this invention are
produced. Amount of the coating layer for coating the refractory
aggregate is varied according to the ingredient and the intended
purpose. Therefore, it is difficult to categorically determine an
amount of the coating layer. However, it is preferred, in general,
that an amount of carboxylic acid is set to be from 0.5 parts by
mass to 5.0 parts by mass with respect to 100 parts by mass of
refractory aggregate. It is preferred that an amount of lubricant
is set to be from 0.02 parts by mass to 0.15 parts by mass with
respect to 100 parts by mass of refractory aggregate. If an amount
of the binder exceeds 5.0 parts by mass with respect to 100 parts
by mass of the refractory aggregate, the kneading of the refractory
aggregate and the binder is made difficult. In contrast, it is
possible to keep the strength if an amount of the binder is set to
be equal to or more than 0.5 parts by mass with respect to 100
parts by mass of the refractory aggregate, compared with a case
where an amount of the binder is set to be less than 0.5 parts by
mass with respect to 100 parts by mass of the refractory aggregate.
Each the refractory aggregate may be coated with the coating layer
by means of the hot coat method, the cold coat method, semi-hot
coat method, and powder solvent method.
[0062] In the hot coat method, the heated refractory aggregate
having the temperature from 110 degrees C. to 180 degrees C. is
mixed with the solid-form binder to melt the solid binder by the
heat of the refractory aggregate. Consequently, the surface of the
refractory aggregate is coated by the molten binder. Then, the
mixture of the refractory aggregates and the binder are cooled. In
this manner, the binder coated refractories having the shape of
granularity and having the flowability. Or, in the hot coat method,
the refractory aggregates having the temperature from 110 degrees
C. to 180 degrees C. are mixed with the liquid solution having the
solvent and the binder dissolved thereto or dispersed thereinto.
Consequently, each the refractory aggregates is coated with the
binder. Then, the solvent is volatilized. In this manner, the
binder coated refractories are produced.
[0063] In the cold coat method, the binder is dispersed into and
dissolved in the solvent such as the water and the methanol,
whereby the binder having the liquid form is prepared. Then, the
binder having the liquid form is added to the refractory aggregates
and mixed with them. Then, the solvent is volatilized. In this
manner, the binder coated refractories are produced.
[0064] In the semi-hot coat method, the binder mixed with or
dispersed into the solvent is added to and mixed with the
refractory aggregates. Then, the solvent is volatilized.
Consequently, the binder coated refractories are produced.
[0065] In the powder solvent method, the binder having the solid
form is broken and then the broken binder is added to and mixed
with the grains of the refractory aggregates and the solvent such
as water and methanol. Then the solvent in the mixture is
volatilized. Consequently, the binder coated refractories are
produced.
[0066] According to the above method, the surface of each the
refractory aggregate is coated with the coating layer.
Consequently, the coating layer has the solid form at 30 degrees
C., whereby the binder coated refractories having the granularity
and the flowability. However, in view of the workability, the hot
coat method is preferably used. In addition, when mixing the
refractory aggregates with the binder, it is possible to further
add the coupling agent for providing the affinity of the refractory
aggregates for the binder. The coupling agent is exemplified by
silane coupling agent. In addition, it is possible to further add
the carbonaceous material such as black lead (graphite).
[0067] When using the binder comprising the sugar group in
combination with the thermosetting resin, it is possible to employ
the method of coating the refractory aggregate with the sugar group
and the thermosetting resin simultaneously. In addition, it is also
possible to employ the method of coating the refractory aggregate
with the thermosetting resin, and then coating the sugar group with
the thermosetting resin on the surface of the refractory
aggregates. Consequently, it is possible to prepare the coating
layer having two layers. That is, either method may be employed
when coating the refractory aggregate with the binder.
[0068] In addition, the binder coated refractories of this
invention produced in the above may be used as the material of, for
example, the casting mold, the refractory bricks, the wall
material, and the ceramics.
[0069] When manufacturing the casting mold with the binder coated
refractories, the binder coated refractories are sprinkled on or
filled in the metallic mold and then heated. That is, when heating
the binder coated refractories, the sugar group in the coating
layer is melted. After melding the sugar group, the binder coated
refractories are solidified. Or, after melding the sugar group, the
binder coated refractories are caused its cross-linking reaction,
whereby the binder coated refractories are hardened. When heating
the sugar group to manufacture the casting mold, the sugar group
causes little harmful gas when the sugar group is solidified or
hardened. It is possible to manufacture the casting mold with
reduction of the environmental pollution.
[0070] In addition, by pouring the molten metal into the casting
mold, the casting metal is manufactured. The sugar group used in
the binder to couple the refractory aggregates with each other for
the casting mold is thermally decomposed easily at a comparative
low temperature. Therefore, the sugar group in the binder is
thermally decomposed by the heat of the molten metal. Consequently,
the casting mold is easily broken by the heat of the molten metal.
In other words, there is no need to apply the impact to the casting
mold in order to demold the casting metal. In addition, there is no
need to decompose the binder by applying the heat over a long
period to demold the casting metal. That is, it is possible to
demold the casting metal from the casting mold.
[0071] In addition, if the binder comprising the phenol resin in
addition to the sugar group is used, it is possible to improve the
bonding force of the binder for bonding the refractory aggregates.
Therefore, it is possible to produce the casting mold having the
mechanical strength.
[0072] As explained above, if the binder comprising the sugar group
in combination with the phenol resin is used, it is possible to
manufacture the casting mold having a high mechanical strength.
However, when the binder comprising the thermosetting resin is
used, there is a possibility that the binder generates the harmful
gas when manufacturing the casting mold and pouring the molten
metal into the casting mold. In addition, the breakage property of
the casting mold after casting is improved. In view of this, when
the thermosetting resin such as the phenol resin is used in
combination with the sugar group, an amount of the thermosetting
resin should be set such that the proportion of the thermosetting
resin in total amount of the binder is equal to or less than 80
percent by mass. In addition, the amount of the thermosetting resin
is preferably set such that the proportion of the thermosetting
resin in the total amount of the binder is equal to or less than 50
percents by mass. In addition, in order to develop the effect of
the thermosetting resin included in the binder, an amount of the
thermosetting resin should be set such that the proportion of the
thermosetting resin in the total amount of the binder is more than
0 (zero) percents by mass. In addition, an amount of the
thermosetting resin is preferably set such that the proportion of
the thermosetting resin in the total amount of the binder is equal
to or more than 10 percents by mass. Furthermore, in order to
develop the sufficient effect of the thermosetting resin included
in the binder, an amount of the thermosetting resin is more
preferably set such that the proportion of the thermosetting resin
in the total amount of the binder is equal to or more than 25
percents by mass.
[0073] Next, one example of the method of manufacturing the casting
mold with the steam is made with FIG. 1. As shown in FIG. 1, the
casting flask 1 which is provided at its inside with a cavity 3 and
which is provided at its upper surface with an inlet 4. The casting
flask 1 is provided at its lower surface with an outlet 6. In
addition, the metallic mesh 5 is provided to the outlet 6. The
casting flask 1 is configured such that the casting flask 1 is
divided into a left section and a right section. Or, the casting
flask 1 is configured such that the casting flask 1 is divided into
an upper section and a lower section. In addition, the binder
coated refractories 2 is stored in the hopper 7. The hopper 7 is
connected to the air supply tube 9 having a valve 8. The nozzle 7a
in a lower end of the hopper 7 is fit in the inlet 4 of the casting
flask 1. Then, the valve 8 is opened. Consequently, the air is
supplied to the hopper 7 to add the pressure in the hopper 7. In
this manner, the binder coated refractories 2 in the hopper 7 are
supplied to the casting flask 1. Thus, the binder coated
refractories are filled in the cavity 3 of the casting flask 1. The
outlet 6 is provided with the mesh 5. Therefore, it is possible to
prevent the leakage of the binder coated refractories 2 to the
outlet 6. If a plurality of the inlets 4 and a plurality of the
outlets 6 are formed to the casting flask 1, the casting flask 1 is
required to have at least one of the inlets 4 for receiving the
binder coated refractories 2.
[0074] After filling the binder coated refractories 2 in the
casting flask 1, the hopper 7 is detached from the inlet 4 of the
casting flask 1. Then, as shown in FIG. 1 B, the air supply pipe 10
is connected to each the inlet 4. The air supply pipe 10 is
configured to supply the steam or the heated gas, selectively.
Firstly, the valve 11 of the air supply pipe 10 is opened to supply
the water vapor to the cavity 3 of the casting flask 1.
[0075] It is preferred that the saturated water vapor is preferably
used as the water vapor. However, superheated steam is more
preferably used as the water vapor. The superheated steam is the
water vapor which has a perfect gas condition having the boiling
temperature or more by heating the saturated water vapor. The
superheated steam is a dry steam having the temperature of 100
degrees or more. The superheated steam produced by heating the
saturated water vapor may include the water vapor which is
constant-pressure expanded without applying the pressure. In
addition, the superheated steam produced by heating the saturated
water vapor also includes "the steam under pressure" that the
pressure is raised without expansion of the steam. The superheated
steam supplied to the casting flask 1 is not limited its
temperature, especially. The superheated steam may be increased its
temperature to 900 degrees C. Therefore, the superheated steam may
be set its temperature from 100 degrees C. to 900 degrees C. as
necessary. In addition, as to the water vapor, it is possible to
use the saturated water vapor having the volume of equal to or more
than 0.5 kgf/cm.sup.2 (0.5 kilograms force per square centimeter)
and equal to or less than 10 kgf/cm.sup.2 (10 kilogram forces per
square centimeter).
[0076] When the water vapor is supplied to the casting flask 1, the
binder coated refractories 2 are exposed to the water vapor.
Consequently, the water vapor loses the latent heat to the binder
coated refractories 2. Therefore, the water vapor is condensed.
However, the water vapor has a high latent heat. Therefore, when
the water vapor is condensed and drawn its heat, the binder coated
refractories 2 are raised their temperature to about 100 degrees C.
by the latent heat. The period where the binder coated refractories
2 are heated to about 100 degrees C. by the transfer of the latent
heat of the water vapor is varied according to "the temperature of
the water vapor", "the flow volume of the binder coated
refractories to the casting flask 1", and "an amount of the binder
coated refractories filled in the casting flask 1". However, the
period that the binder coated refractories 2 is heated to about 100
degrees C. is short time in a range of from 3 seconds to 30
seconds. The water vapor supplied into the casting flask 1 through
the inlet 4 heats the binder coated refractories 2 in the casting
flask 1 and exhausted through the outlet 6. In addition, by further
supplying the superheated steam into the casting flask, the
condensed water is evaporated. Consequently, the binder is heated
to the temperature that the binder is solidified or hardened.
According to this, it is possible to easily manufacture the casting
mold.
[0077] In addition, after the binder coated refractories 2 are
raised its temperature to 100 degree C., the air to be supplied to
the air supply pipe 10 is changed to the heated gas. Then, the
heated gas is supplied to the casting flask 1. The heated gas is
only required its condition where the water content ratio of the
heated gas is lower than the above water vapor. Therefore, it is
possible to use the heated air. For example, it is possible to use
the heated air in the atmosphere as the heated gas and to supply
the heated gas to the air supply pipe 10. In addition, it is
possible to prepare "the water vapor mixed with the heated air".
Consequently, it is possible to decrease the water content amount
of the mixture gas. Therefore, the mixture gas may be used as the
heated gas. The heated gas is set to have the temperature of such
as, but not limited to, equal to or more than 100 degrees C. In
addition, the heated gas is set to have the temperature of equal to
or more than the temperature sufficient to cause the solidification
or the hardening of the binder of the binder coated refractories
2.
[0078] After supplying the water vapor into the casting flask 1,
the binder coated refractories 2 are quickly raised their
temperature to about 100 degrees C. by the latent heat transferred
when the water vapor is condensed. However, in order to raise the
temperature of the binder coated refractories to 100 degrees C. or
more, there is a need to evaporate the condensed water. The
condensed water is evaporated by the heating caused by the water
vapor supplied thereafter. However, as explained above, the water
vapor has high water content. Therefore, the water vapor has a low
efficiency of evaporating the condensed water. In view of this, the
heated gas is supplied to the casting flask 1. The heated gas has
low water content, compared with the water vapor. In addition, the
heated gas is a dry air having low moisture. Therefore, the heated
gas supplied to the casting flask 1 dries the condensed water
created in the casting flask 1 in short times. According to the
evaporation experiment of the water by the airflow of the
superheated steam and the airflow of the heated gas, the
evaporation rate of the water with respect to the superheated steam
is greater than the evaporation rate of the water with respect to
the heated gas under a condition where the temperature is equal to
or less than about 170 degrees C. (T. Yosida, Hyodo, T., Ind. Eng.
Chem. Process Des. Dev., 9 (2), 207-214 (1970)) As will be
understood from the above report, applying the heated gas to the
casting flask 1 makes it possible to evaporate the condensed water
and dry the binder coated refractories at short times, compared
with a case where the water vapor is continued to be supplied to
the casting flask 1.
[0079] Therefore, within short times of supplying the heated gas
into the casting flask 1, the binder coated refractories 2 are
increased their temperature to equal to or more than 100 degrees C.
Consequently, it is possible to increasing rate of the temperature
in the casting mold 1 to equal to or more than the temperature
sufficient to solidify-harden the binder of the binder coated
refractories 2. In addition, according to this, it is possible to
manufacture the casting mold having the high strength at short
times.
[0080] In addition, when the condensed water is heated and
evaporated by the water vapor explained in the above, the water
vapor is decreased its volume. Consequently, if using the water
vapor, there is a problem that the pressure of the water vapor is
decreased and the water vapor is remained in the casting flask 1.
On account of this, "drying" and "temperature increasing" of the
binder coated refractories require a lot of time. However, the
heated gas has low volume shrinkage due to the condensation. In
addition, the heated gas has little decrease of the pressure.
Therefore, the heated gas is supplied to an entire of the casting
flask 1 from the inlet 4 to the outlet 6. Therefore, it is possible
to wholly and uniformly cause the thermal reaction in the casting
flask 1, to wholly and uniformly dry the casting flask 1, and to
wholly and uniformly increase the temperature of the casting flask
1.
[0081] The period where the heated gas is supplied to the casting
mold 1 depends on "the temperature of the heated gas", "the flow
volume of the heated gas supplied to the casting flask 1", "an
amount of the binder coated refractories 2 filled in the casting
flask 1", and "an amount of the condensed water in the casting mold
1". However, in general, the period where the heated gas is
supplied to the casting mold 1 is short times of, for example, from
5 seconds to 30 seconds. Therefore, after 10 seconds to 1 minute
from starting supplying the water vapor into the casting flask 1,
the casting mold is manufactured.
[0082] As explained above, by using the water vapor, the binder
coated refractories are heated by the latent heat of the high
condensation of the water vapor in a moment, whereby the binder in
the coating layer is solidified-hardened. Therefore, there is no
need to heat the casting flask 1 itself at a high temperature in
advance. It is possible to stably manufacture the casting mold at
short times. In addition, when the harmful gas is generated, the
harmful gas is dissolved in the condensed water of the water vapor.
Therefore, it is possible to reduce the environmental pollution.
Furthermore, when the water vapor is supplied into the casting
flask 1 to expose the binder coated refractories to the water
vapor, the water vapor is drawn its heat. Consequently, the
condensed water is developed. According to the condensed water, the
sugar group in the coating layer is swelled, whereby the solid-form
sugar group is changed into sticky paste condition. Consequently,
the refractory aggregates are bonded by the sugar group having the
sticky paste condition. Therefore, the casting mold having the high
strength is produced.
[0083] Next, the explanation of the method of manufacturing the
casting mold by freezing of the water is made. At first, the binder
coated refractories of this invention are added to and mixed with
the water and mixed with. Then, the mixture of the binder coated
refractories and the water is filled in the casting flask. Then the
casting flask 1 is cooled in the refrigerator to freeze the water
in the casting mold. In this manner, by freezing the water, the
binder coated refractories are bonded with the each other, whereby
the casting mold is manufactured. An amount of the water with
respect to the binder coated refractories is preferably set to from
3 pacts by mass to 20 parts by mass of the water with respect to
the 100 parts by mass of the binder coated refractories.
[0084] It is noted that, in using the freezed casting mold, when
the molten metal is poured into the casting mold which is
solidified only by the ice, the ice is easily melt. Therefore, it
is difficult to manufacture the large casting mold. In contrast, in
the freezed casting mold using the binder coated refractories with
the coating layer which has the sugar group, the sugar group in the
coating layer is swelled to have a sticky paste condition. By the
sugar group having the sticky paste condition, the refractory
aggregates are bonded. In addition, the heat applied during pouring
the molten metal into the casting mold solidifies-hardens the sugar
group. Therefore, it is possible to maintain the strength of the
casting mold. In this manner, this makes it possible to manufacture
the casting mold having the large size.
[0085] In addition, as explained above, by adding the water to the
binder coated refractories in this invention, mixing them, and
filling the mixture in the casting flask, the refractory aggregates
are bonded by the sugar group which is swelled to have a sticky
paste condition. Therefore, it is possible to maintain the casting
mold's form which has the same shape of the cavity of the casting
flask. In addition, by demolding the casting mold from the casting
flask and solidifying-hardening the sugar group having the sticky
paste condition, the casting mold is produced. In this manner, it
is possible to manufacture the casting mold without freezing.
EXAMPLE
[0086] Next, the example is specifically explained in the
followings.
Examples 1 to 9
[0087] The 30 kilograms flattery silica sand heated to 130 degrees
C. was supplied to the whirlmixer. Then, the water solution of "the
sugar group and the curing agent indicated in the Table 1"
dissolved to or dispersed in the water of 450 grams was supplied to
the whirlmixer. Then, the mixture is kneaded for 90 seconds. After
breaking the mixture, the calcium stearate as the lubricant was
added to the mixture. Then, the aeration was made to the mixture.
In this manner, the binder coated refractories having the coating
layer made of the sugar group was obtained. The binder coated
refractories has the coating layer having the weight ratio of 2
percents by mass.
[0088] In addition, as shown in Table 1, the sugar group of the
following was used. [0089] Dextrin ("No4-C" "No. 102-S" "ND-S" of
NIPPON STARCH CHEMICAL Col. Ltd.) [0090] Enzyme Denaturation
Dextrin ("Amycol No7-H" "Amycol No6-H" "amycol No3-L" of NIPPON
STARCH CHEMICAL Col. Ltd.) [0091] White Superior Soft Sugar
(Sucrose 98 percents by mass and reducing sugar 0.7 percents by
mass) It is noted that, regarding the dextrine, the molecular
masses of them descends in the order of "No4-C", "No102-S", and
"ND-S". Regarding the Enzyme Denaturation Dextrin, the molecular
masses of them descends in the order of "Amycol No7-H", "Amycol
No6-H", and "Amycol No3-L". In addition, the citric acid was used
as the curing agent. In using the citric acid, the citric acid was
used as a form of solution of the citric acid dissolved in the
water.
TABLE-US-00001 [0091] TABLE 1 Example (Gram) 1 2 3 4 5 6 7 8 9
Flattary Silica Sand 30000 30000 30000 30000 30000 30000 30000
30000 30000 Dextrin No4-C 600 588 No102-S 600 ND-S 600 300 Enzyme
Amycol 600 Denaturation No7-H Dextrin Amycol 600 No6-H Amycol 600
No3-L White Superior 600 300 Soft Sugar Citric Acid 12
Examples 10 to 13
[0092] The 30 kilograms flattery silica sand heated to 140 degrees
C. was supplied to the whirlmixer. Then, the phenol resin indicated
in Table 2 was added to the whirlmixer and then mixed with flattery
silica sand. Then, the water solution of "the sugar group in Table
2" was dissolved to or dispersed in the water of 450 grams was
added to the mixture of the flattery silica sand and the phenol
resin. Then, kneading the mixture for 90 seconds was performed.
Subsequently, the aeration was made, whereby the binder coated
refractories having the coating layer including the sugar group and
the phenol resin was produced. The binder coated refractories had
the coating layer having the weight ratio of 2.0 percents by
mass.
Comparative Examples 1 to 3
[0093] The 30 kilograms flattery silica sand heated to 140 degrees
C. was supplied to the whirlmixer. Then, the phenol resin indicated
in Table 2 was added to the whirlmixer. Subsequently, mixing them
for 30 seconds was made. Then, the water solution of
"hexamethylenetetramine" dissolved in the water of 450 grams was
added to the mixture of the flattery silica sand and the phenol
resin. Then, kneading them for 90 seconds was performed. After
breakage of the mixture, as to the lubricant, the calcium stearate
of 30 grams was added to the mixture and then kneaded for 15
seconds. In addition, the aeration was made. Consequently, the
binder coated refractories having the coating layer made of phenol
resin was produced. In the binder coated refractories, the weight
ratio of the coating layer has 2.0 percents by mass.
[0094] In addition, as shown in Table 2, the followings are used as
the sugar group. [0095] Dextrin ("ND-S" of NIPPON STARCH CHEMICAL
Co. Ltd.) [0096] White Superior Soft Sugar (Sucrose 98 percents by
mass and reducing sugar 0.7 percents by mass) In addition, the
followings are used as the phenol resin. [0097] Novolac type
phenolic resin (#4800 of Lignyte Co. Ltd Softening point: 91
degrees C.) [0098] Resol-type phenolic resin ("LT-9" of Lignyte Co.
Ltd Softening point: 91 degree C. Gelation time: 120 seconds (at
150 degrees C.))
TABLE-US-00002 [0098] TABLE 2 Comparative Example (Gram) Example
(Gram) 10 11 12 13 1 2 3 Flattery Silica Sand 30000 30000 30000
30000 30000 30000 30000 Dextrin ND-S 450 300 150 150 Novolac Type
52.2 105 157.2 105 210 600 Phenolic Resin Resol Type 97.8 195 292.8
195 390 600 Phenolic Resin White Superior Soft Sugar 150
Hexamethylenetetramine 90
[0099] The binder coated refractories of the example 1 to 13 and
the comparative example 1 to 3 were measured their fusion points
according to JACT testing methodology C-1. In addition, according
to the bending strength testing methodology of JIS K6910 (JIS:
Japanese Industrial standard), the test pieces were prepared and
measured their bending strength. When preparing the testing pieces,
the odor intensity and the kind of the odor were measured by
snuffing the odor of the test piece. Furthermore, the test pieces
of the examples and the comparative examples which use the phenol
resin were measured their formaldehyde and ammonia by use of the
gas detector tube of KITAGAWA type. Table 3 indicates these
results.
TABLE-US-00003 TABLE 3 Example 1 2 3 4 5 6 7 8 Fusion Point 135.6
138.2 125.6 140.3 131.6 129.5 108.3 118.5 (Degree C.) Bending
strength 30.4 32.4 34.3 24.5 29.4 40.2 132.4 83.4 (N/cm.sup.2) Odor
Strength Most Most Most Most Most Most Minute Minute Minute Minute
Minute Minute Minute Minute Level Level Level Level Level Level
Level Level Kind of Odor Sweet Sweet Sweet Sweet Sweet Sweet Very
Very Sweet Sweet Concentration in Air of -- -- -- -- -- -- -- --
Formaldehyde and Ammonia Example Comparative Example 9 10 11 12 13
1 2 3 Fusion Point 123.5 120.3 105.3 102.8 102.4 102.1 103.2 105.5
(Degree C.) Bending strength 49.0 93.2 279.5 380.5 331.5 591.3
573.7 642.3 (N/cm.sup.2) Odor Strength Minute Minute Minute Minute
Minute Middle Middle Strong Level Level Level Level Level Kind of
Odor Sweet Burnt Burnt Burnt Burnt Formaldehyde Formaldehyde
Ammonia Sour Odor Odor Odor Odor Odor Odor Odor Concentration in
Air of -- Not Not Not Not 0.35 0.50 5.0 Formaldehyde and Detected
Detected Detected Detected (Formaldehyde) (Formaldehyde) (Ammonia)
Ammonia
[0100] As will be understood from Table 3, each the examples of
them did not generate the strong odors, and did not pollute the
environment.
[0101] Next, the casting molds were produced with the binder coated
refractories of examples 1 to 13 and comparative examples 1 to 3.
Specifically, the casting flask having the cavity size of 20
millimeters by 10 millimeters by 80 millimeters was prepared. Then,
the casting flask was preheated to 120 degrees C. Then, the binder
coated refractories was filled into the casting flask at the air
pressure of 0.1 MPa (MPa: megapascal) of gauge pressure. Then, the
air supply pipe was connected to the casting flask. Subsequently,
the superheated steam was supplied into the casting flask. The
superheated steam had the temperature of 350 degree C. and the
gauge pressure of 0.45 MPa (MPa: megapascal). The superheated steam
was supplied into the casting flask at the flow rage of 60 kg/h
(kg/h: kilograms per hour) for 20 seconds. The superheated steam
was produced from the saturated water vapor which was produced with
using the superheated-steam-generation-unit ("GE-100" manufactured
by Nomura Giko Co. Ltd) from the saturated water vapor having the
gauge pressure of 0.4 MPa (megapascal) and the temperature of 143
degrees C. generated by the boiler.
[0102] According to the above, the casting mold having the size of
20 millimeters by 10 millimeters by 80 millimeters as the test
piece for the bending strength test was produced. In addition,
demolding the casting mold and measuring the odor of the casting
mold by snuffing the odor of the test piece were performed.
Furthermore, the casting mold were measured their bending strength
on the basis of JIS K6910 (JIS: Japanese Industrial Standards).
Table 4 indicates the results.
[0103] Furthermore, regarding the casting molds, the breaking test
was performed. In the breaking test, wrapping the casting molds by
the aluminum foil, arranging them on the hearth, and heating them
in drying-by-heating apparatus to 400 degrees C. for 30 minutes
were performed. Then, after cooling the casting molds, the bending
strengths of them were measured on the basis of JIS K6910. In
addition, the breaking ratios were calculated on the basis of the
following formula with using the factors of "the bending strength
before heating" and "the bending strength after heating". Table 4
indicates the results.
[Breaking ratio(percents)=100-(bending strength after
heating/bending strength before heating).times.100]
TABLE-US-00004 TABLE 4 Example 1 2 3 4 5 6 7 8 Odor of A A A A A A
B B Casting Mold Bending 153.0 169.7 308.9 196.1 207.9 154.9 279.5
387.4 Strength of the Casting Mold (N/cm.sup.2) Bending 12.7 15.7
23.5 17.7 25.5 11.8 25.5 66.7 Strength of the Casting Mold after
Heating After Heating (N/cm.sup.2) Breaking Ratio 91.7 90.8 92.4
91.0 87.7 92.4 92.2 82.8 (%) Comparative Example Example 9 10 11 12
13 1 2 3 Odor of A A B B B C C D Casting Mold Bending 387.4 220.6
442.3 591.3 493.9 554.1 589.4 563.9 Strength of the Casting Mold
(N/cm.sup.2) Bending 77.5 83.4 216.7 374.6 298.1 395.3 441.3 475.6
Strength of the Casting Mold after Heating After Heating
(N/cm.sup.2) Breaking Ratio 80.0 62.3 51.0 36.7 39.6 28.7 25.1 15.1
(%) A: Very little Odor B: Weak Odor C: Strong Odor D: Very Strong
Odor
[0104] As shown in Table 4, each the example did not emit the
strong odor and did not pollute the environment. In addition, each
the example has a high and good breaking ratio.
[0105] In addition, in preparing the casting mold with the binder
coated refractories of the examples 1 to 13 and the comparative
examples 1 to 3, the superheated steam was supplied into the cavity
for 10 seconds, as explained above. Then, the connection of the air
supply pipe was varied to the heated air. Then, the heated air
having the 350 degrees C. was supplied to the binder coated
refractories for 20 seconds. The heated air was that the air having
relative humidity of 63 percents at 25 degrees C. which is produced
by the hot-air-generation device (TSK-31 of TAKETSUNA MANUFACTORY
CO., LTD) was heated to 350 degrees C. The heated air was supplied
into the casting mold at the flow rate of 5.7 m.sup.3/minute (cubic
meters per minute).
[0106] According to the above, the casting mold having the size of
20 millimeters by 10 millimeters by 80 millimeters for the test of
the bending strength was molded and then the odor of the casting
mold after demolding was measured by snuffing. Further, the casting
molds were measured their bending strength on the basis of JIS
K6910 (JIS: Japanese Industrial Standards). Table 5 shows the
results.
TABLE-US-00005 TABLE 5 Example 1 2 3 4 5 6 7 8 Odor of the A A A A
A A B B Casting mold Bending 160.1 175.3 312.4 200.1 211.5 161.3
295.0 400.6 Strength of the Casting Mold (N/cm.sup.2) Comparative
Example Example 9 10 11 12 13 1 2 3 Odor of the A A B B B C C D
Casting mold Bending 393.5 231.5 446.5 600.4 508.5 547.3 591.6
570.6 Strength of the Casting Mold (N/cm.sup.2) A: Very little Odor
B: Weak Odor C: Strong Odor D: Very Strong Odor
[0107] As shown in Table 5, each the examples did not emit the
strong odor, and did not pollute the environment. In addition,
compared with Table 4, the casting molds were improved their
strengths.
[0108] Next, the 100 parts by mass of the binder coated
refractories in the example 4 was mixed with 5 parts by mass of the
water, and filled it in the metallic mold for manufacturing the
test piece for testing the bending strength on the basis of JIS
K6190 (Japanese Industrial Standards). Then, the upper surface of
the mixture in the casting mold is flatted by the paddle. Then, the
mixture was freezed by the fridge at minus 20 degrees, and then the
freezed mixture was demolded. Then, the test piece was immediately
measured its bending strength. The result of the bending strength
is 198 N/cm.sup.2 (Newton per square centimeters).
[0109] As a reference, the test piece was produced with the
flattery silica sand, instead of the binder coated refractories and
was measured its bending strength. The result is 143 N/cm.sup.2
(Newton persquare centimeters). Consequently, it is confirmed that
using the binder coated refractories makes it possible to produce
the casting mold having the high strength.
[0110] In addition, the freezed test pieces of the above were
naturally defrosted at the room temperature (25 degrees C.) and
then dried for 24 hours. According to this, the test piece produced
from only the flattery silica sand is broken, whereby only the sand
mound was remained. However, the test piece produced by freezing
the binder coated refractories of the example 4 was kept to have
the solidified condition to have its form as the test piece. That
is, it is possible to use the casting mold directly.
Examples 14, 15, and 16
[0111] 30 kg (kilograms) of the flattery silica sand heated to 130
degrees C. was supplied to the whirlmixer and then the water
solution having the sugar group and the curing agent for the sugar
group which are indicated in Table 6 dissolved in or dispersed to
450 grams of the water was add to the flattery silica sand in the
whirlmixer. Then, the mixture was mixed for 90 seconds. Then, after
breaking the mixture, 30 grams of the calcium stearate used as the
lubricant was added to the mixture and then mixed them for 15
seconds. Furthermore, the mixture was made aeration. Consequently,
the binder coated refractories having the coating layer including
the sugar group was prepared. In this binder coated refractories,
the weight ratio of the coating layer was 0.33 percents by mass in
the example 14, 0.5 percents by mass in the example 15, and 5.0
percents by mass in the example 16.
[0112] In addition, as shown in Table 6, as to the sugar group,
Dextrin ("ND-S" of NIPPON STARCH CHEMICAL Col. Ltd.) was used.
TABLE-US-00006 TABLE 6 Example (gram) 3 14 15 16 Flattery Silica
Sand 30000 30000 30000 30000 Dextrin ND-S 600 100 150 1500
Example 17, 18, and Comparative Example 4
[0113] The flattery silica sand 30 kg (kilograms) heated at 140
degrees C. was supplied to the whirlmixer. Then, the phenol resin
indicated in Table 7 was added to the flattery silica sand. Then,
they were mixed with each other for 30 seconds. In addition, the
water solution having the sugar group indicated in Table 7 which
was dissolved in or dispersed to the 450 grams of the water was
added to the mixture. Subsequently, they were mixed for about 90
seconds. After breaking the mixture, 30 grams of the calcium
stearate as the lubricant was added to the mixture and then the
they were kneaded for 15 seconds. Then, the aeration of them were
made. Consequently, the binder coated refractories having the
coating layer including the sugar group and the phenol resin was
produced. In this binder coated refractories, the weight ratio of
the coating layer is 2.0 percents by mass. In addition, the
proportion of the phenol resin with respect to the total amount of
the binder was 10 percents by mass in the example 17. The
proportion of the phenol resin with respect to the total amount of
the binder was 80 percents by mass in the example 18. The
proportion of the phenol resin with respect to the total amount of
the binder was 90 percents by mass.
TABLE-US-00007 TABLE 7 Comparative example Example (gram) (gram) 10
11 12 17 18 4 Flattery Silica Sand 30000 30000 30000 30000 30000
30000 Dextrin ND-S 450 300 150 540 120 60 Novolac-type Phenolic
Resin 52.2 105 157.2 21 168 189 Resol-type Phenolic Resin 97.8 195
292.8 39 312 351
[0114] The binder coated refractories of the examples 3, 14, 15,
16, 10, 11, 12, 17, and 18, and comparative example 4 were measured
their fusion points on the basis of the JACT testing methodology
C-1. In addition, the test pieces were manufactured on the basis of
the test of bending strength in JIS K6910 (JIS: Japanese Industrial
Standards) and were measured their bending strengths. In addition,
when manufacturing the test pieces, the strength of the odor and
the kind of the odor were measured by snuffing. In addition, the
test pieces using the phenol resin of the examples and the
comparative examples were measured their formaldehyde and their
ammonia by use of the gas detector tube of KITAGAWA type. Table 8
indicates the results.
TABLE-US-00008 TABLE 8 Example Comparative 3 14 15 16 10 11 12 17
18 Example 4 Fusion Point 125.6 130 129.0 124.3 120.3 105.3 102.8
108.0 101.5 99.3 (Degree C.) Bending Strength 34.3 18.0 15.0 40.5
93.2 279.5 380.5 89.0 435.0 425.1 (N/cm.sup.2) Odor Strength Most
Most Little Minute Minute Minute Minute Most A little Strong Minute
Little Level Level Level Level Level Minute Strong Level Level
Level Kind of Odor Sweet Sweet Sweet Burnt Burnt Burnt Burnt Sweet
Sweet Formaldehyde Odor Odor Odor Odor Odor Concentration of -- --
-- -- Not Not Not Not Not 0.4 Formaldehyde (ppm) Detected Detected
Detected Detected Detected
[0115] As shown in Table 8, each the examples did not emit the
strong odor, and did not pollute the environment.
[0116] Next, the casting molds were manufactured with using the
binder coated refractories of examples 3, 14, 15, 16, 10, 11, 12,
17, and 18, and comparative example 4. That is, the casting flask
having the cavity size of 20 millimeters by 10 millimeters, by 80
millimeters was prepared and preheated. Then, the binder coated
refractories was filled in the casting flask by the air pressure of
0.1 MPa (mega pascal) of gauge pressure. Subsequently, the casting
flask was connected to the air supply pipe and then the superheated
steam was supplied to the casting flask. The superheated steam had
350 degrees C. and 450 MPa (mega pascal) of the gauge pressure. The
superheated steam was produced by the superheated-steam-generation
device (GE-100.degree. F. NOMURA GIKO Co. Ltd) such that the
saturated water vapor having 143 degrees C. and 0.4 MPa (mega
pascal) of the gauge pressure generated by the boiler is heated by
the superheated-steam-generation device. The superheated steam was
supplied into the casting flask at the flow rate of 60 kg/h
(kilogram per hour).
[0117] According to this, the casting mold having the size of 20
millimeters by 10 millimeters by 80 millimeters for the test of the
bending strength was produced. In addition, the odor of the casting
mold after demolding was measured by snuffing. Furthermore, the
casting mold was measured its bending strength on the basis of JIS
K6910 (Japanese Industrial Standards). Table 9 indicates the
results.
[0118] Furthermore, regarding the casting molds, the breaking test
was performed. In the breaking test, wrapping the casting molds by
the aluminum foil, arranging them on the hearth, and heating them
in drying-by-heating apparatus to 400 degrees C. for 30 minutes.
Then, after cooling the casting molds, the bending strengths of
them were measured on the basis of JIS K6910. (JIS: Japanese
Industrial Standards). In addition, the breaking rates were
calculated from the following formula with using the bending
strength before heating and the bending strength after heating.
Table 9 indicates the results.
[Breaking ratio(percents)=100-(bending strength after
heating/bending strength before heating).times.100]
TABLE-US-00009 TABLE 9 Example Comparative 3 14 15 16 10 11 12 17
18 Example4 Odor of Casting Mold Little Minute Little Minute Little
Minute Minute Little Minute Extremely Level Level Level Level Level
Level Level Level Level Strong Bending Strength of 308.9 85 110.0
418.6 220.6 442.3 591.3 245.1 689.0 745.1 Casting Mold Bending
Strength of 23.5 1.7 3.3 52.2 83.2 216.7 374.4 12.7 478.9 593.1
Casting Mold After heat treatment (N/cm.sup.2) Breaking ratio 92.4
98.0 97.0 87.5 62.3 51.0 36.7 94.8 30.5 20.4
[0119] As shown in Table 9, each the examples did not emit the
strong odors and did not pollute the environment. Further, the
casting molds of the examples has high breaking ratios.
[0120] In addition, in preparing the casting mold with the binder
coated refractories of the examples 3, 14, 15, 16, 10, 11, 12, 17,
and 18 and the comparative example 4, the superheated steam was
supplied into the cavity for 10 seconds, as explained above. Then,
the connection of the air supply pipe was varied to the heated air.
Then, the heated air having the 350 degrees C. is supplied to the
binder coated refractories for 20 seconds. The heated air was the
air having relative humidity of 63 percents at 25 degrees C. which
is produced by the hot-air-generation device (TSK-31 of TAKETSUNA
MANUFACTORY CO., LTD) was heated to 350 degrees C. The heated air
was supplied into the casting mold at the flow rate of 5.7
m.sup.3/minute (cubic meters per minute).
[0121] According to the above, the casting molds having the size of
20 millimeters by 10 millimeters by 80 millimeters for test of the
bending strength were measured their odor by snuffing after
demolding. Table 10 shows the results. In addition, regarding the
casting molds, the bending strengths were measured on the basis of
JIS K6910. Table 10 shows the results.
TABLE-US-00010 TABLE 10 Example Comparative 3 14 15 16 10 11 12 17
18 Example 4 Odor of Casting Mold Little Minute Little Minute
Little Minute Minute Little Minute Extremely Level Level Level
Level Level Level Level Level Level Strong Bending Strength of
312.4 83.8 112.5 420.3 231.5 446.5 600.4 248.5 69.5 751.0 Casting
Mold (N/cm.sup.2) Bending Strength of 23.7 1.8 3.5 50.0 86.4 213.9
375.2 12.4 471.2 592.5 Casting Mold After heat treatment
(N/cm.sup.2) Breaking ratio 92.4 97.9 96.9 88.1 62.7 52.1 37.5 95.0
32.2 21.1
[0122] As will be understood from the above, each the example did
not emit the strong odor and did not pollute the environment.
Further, each the examples has a good breaking ratio.
Examples 19 to 24
[0123] 30 kilograms of the flattery silica sand was heated to 130
degrees C. and supplied it to the whirlmixer. Then, the water
solution comprising the sugar groups indicated in Table 11 and 450
grams dissolved in or dispersed to the water was added to the
whirlmixer. Then, the mixture was kneaded. After breaking, 30 grams
of the calcium stearate was added to the mixture and then kneaded
for 15 seconds. After kneading, the aeration was made.
Consequently, the binder coated refractories having the coating
layer made of the sugar groups was produced. In the binder coated
refractories, the weight ratio of the coating layer was 20 percents
by mass.
[0124] In addition, as shown in Table 11, the sugar group of the
following was used. Dextrin ("No4-C" "No. 102-S" "ND-S" of NIPPON
STARCH CHEMICAL Col. Ltd.) Enzyme Denaturation Dextrin ("Amycol
No7-H" "Amycol No6-H" "amycol No3-L" of NIPPON STARCH CHEMICAL Col.
Ltd.) That is, the binder coated refractories of the examples 19 to
24 is same as the binder coated refractories of the examples 1 to
6.
TABLE-US-00011 TABLE 11 Example (gram) 19 20 21 22 23 24 Flattery
Silica Sand 30000 30000 30000 30000 30000 30000 Dextrin No4-C 600
No102-S 600 ND-S 600 Enzyme Amycol No7-H 600 Denaturation Amycol
No6-H 600 Dextrin Amycol No3-L 600
[0125] Next, the casting molds were produced with the binder coated
refractories of examples 19 to 24. That is, the casting flask
having the cavity size of 20 millimeters by 10 millimeters by 80
millimeters was prepared. Then, the casting flask was preheated to
120 degrees C. Then, the binder coated refractories was filled into
the casting flask at the air pressure of 0.1 MPa (MPa: megapascal)
of gauge pressure. Then, the air supply pipe was connected to the
casting flask. Subsequently, the superheated steam was supplied
into the casting flask. The superheated steam had the temperature
of 350 degree C. and the gauge pressure of 0.45 MPa (MPa:
megapascal). The superheated steam was supplied into the casting
flask at the flow rage of 60 kg/h (kg/h: kilograms per hour) for 15
seconds. The superheated steam was produced from the saturated
water vapor which was produced with using the
superheated-steam-generation-unit ("GE-100" manufactured by Nomura
Giko Co. Ltd) from the saturated water vapor having the gauge
pressure of 0.4 MPa (megapascal) and the temperature of 143 degrees
C. generated by the boiler. It is noted that a lengthwise direction
of the cavity of the casting flask has 80 millimeters. The casting
flask was provided at its one longitudinal end defined as the first
end and it's the other longitudinal end defined as the second end,
the first end being provided with the water vapor inlet, the second
end being provided with the water vapor outlet.
[0126] In this manner, the casting molds having the size of 20
millimeters by 10 millimeters by 80 millimeters for test of the
bending strength were produced. Therefore, the casting molds had
heights of 80 millimeters. In addition, each the casting mold had
an upper section and a lower section. The upper section is defined
by a section above the center of the height direction of the
casting mold. The lower section is defined by a section below the
center of the height direction of the casting mold. When the
casting mold was located in the casting flask, the upper section of
the casting mold corresponds to the first end of the casting flask.
When the casting mold is located in the casting flask, the lower
section of the casting mold corresponds to the second end of the
casting flask. Regarding the casting molds, the bending strength
were measured on the basis of JIS K 6910. Furthermore, the strength
(resistance of breaking) is measured on the basis of the
hand-scratching test of JIS K5400 "coating material test" 8.4.2.
The results are shown in Table 12.
TABLE-US-00012 TABLE 12 Example 1 2 3 4 5 6 Fusion Point 135.6
138.2 125.6 140.3 131.6 129.5 (Degree C.) Bending 30.4 32.4 34.3
24.5 29.4 40.2 Strength (N/cm.sup.2) Strength of 7H 6H 6H 6H 6H 6H
Upper Section Strength of 4H 4H 3H 4H 3H 3H Lower Section Odor
Strength Most Most Most Most Most Most Minute Minute Minute Minute
Minute Minute Level Level Level Level Level Level Kind of Odor
Sweet Sweet Sweet Sweet Sweet Sweet Example 19 20 21 22 23 24
Fusion Point 135.6 138.2 125.6 140.3 131.6 129.5 (Degree C.)
Bending 36.8 39.5 42.2 29.9 36.2 49.8 Strength (N/cm.sup.2)
Strength of 9H or 9H or 9H or 9H or 9H or 9H or Upper Section more
more more more more more Strength of 9H or 9H 9H 9H 8H 9H Lower
Section more Odor Strength Most Most Most Most Most Most Minute
Minute Minute Minute Minute Minute Level Level Level Level Level
Level Kind of Odor Sweet Sweet Sweet Sweet Sweet Sweet
[0127] Table 12 shows that the casting molds of Examples 19 to 24
had high strengths, compared with the casting molds of Examples 1
to 6. That is, the casting molds manufactured by the method of
Examples 19 to 24 are sufficiently dried their inside according to
the heating of the binder coated refractories in the solidification
or hardening step. As a result, the bending strengths were
improved.
[0128] Furthermore, as shown in Table 12, the test pieces of the
casting molds of Examples 19 to 24 had the strengths which are
greater than the strengths of the test pieces of the casting molds
in Examples 1 to 6. In addition, the lower sections of the casting
molds of Examples 1 to 6 had the strengths which is lower than the
strength of the upper sections of the casting molds of Examples 1
to 6. However, the surface of the lower section of the test piece
of the casting mold of Examples 19 to 24 had the strengths which
were approximately equivalent to the strengths of Examples 19 to
24. The results regarding the casting molds of the examples 19 to
24 indicates that the casting mold of the examples 19 to 24 had the
uniform strengths.
[0129] That is, when manufacturing the casting mold according to
the method indicated in Examples 19 to 24, the binder coated
refractories is firstly filled in the casting flask. Subsequent to
the filling step, the solidification or hardening step is
performed. In the solidification or hardening step, the casting
flask receives the supply of the saturated water vapor. According
to this step, the binder coated refractories within the casting
flask got wet. According to the moisture of the binder coated
refractories, the sugar group had the sticky paste condition. Then,
the step of supplying the superheated steam into the casting flask
to heat the binder coated refractories was performed. Consequently,
the binder coated refractories was increased its temperature. In
this manner, the binder coated refractories in the casting flask
was heated. As the binder coated refractories was increased its
temperature, the binder coated refractories in the casting flask
was sufficiently dried, thoroughly. Furthermore, increasing the
temperature of the binder coated refractories causes the
solidification and the hardening between the binders in the coating
layers. Therefore, it is possible to obtain the uniform strength of
the binder coated refractories in the casting flask.
[0130] As explained above, the method of manufacturing the casting
mold comprises a filling step and a solidifying-hardening step. In
the filling step, filling the binder coated refractories in the
casting flask is performed. The binder coated refractories
comprises the refractory aggregates and the coating layers. The
refractory aggregates have the fire resistance property. Each the
refractory aggregate is coated at its surface with the coating
layer. The coating layer comprises the binder which includes the
sugar group. The coating layer has a solid form. In the
solidification-hardening step, supplying the first water vapor into
the casting flask is performed. Consequently, the sugar group is
made to have the sticky paste condition. Subsequent to the step of
supplying the first water vapor, heating the binder coated
refractories is performed to solidify-harden the binders in the
coating layers. In this manner, the binder coated refractories are
bonded.
[0131] Consequently, the casting mold may be manufactured with
preventing the emission of the gas which pollute the
environment.
[0132] The binder coated refractories is preferably heated at a
temperature from 100 degree C. or more to 350 degree C. or
less.
[0133] In addition, the first water vapor supplied into the casting
flask preferably has the temperature from 100 degrees C. or more to
400 degrees C. or less.
[0134] In addition, as shown in Examples 10, 11, 12, 13, 17, and
18, the coating layer comprises the thermosetting resin.
[0135] In addition, the thermosetting resin is the phenol
resin.
[0136] Consequently, it is possible to provide the strength of the
casting mold.
[0137] Furthermore, it is preferred that the coating layer has the
carboxylic acid. In addition, it is preferred that an amount of the
carboxylic acid with respect to the total amount of the sugar group
is 0.1 parts by mass or more and 10 parts by mass or less.
[0138] In addition, in the solidifying-hardening step, supplying
the first water vapor to provide the sugar group of the binder with
the sticky paste condition is performed. Then, increasing the
temperature of the binder having the sticky paste condition by the
latent heat of the first water vapor to solidify-harden the binder
having the sticky paste condition is performed.
[0139] In addition, in the solidifying-hardening step, subsequent
to the step of supplying the first water vapor, "supplying the
heated gas into the casting flask" is performed to evaporate the
condensed water within the casting flask and to increase the
temperature to temperature for solidifying-hardening the
binder.
[0140] In addition, the heated gas preferably has a temperature of
100 degree C. or more and 500 degree C. or less.
[0141] In this case, the heated gas having a little moisture
instantaneously evaporates the condensed water. Therefore, it is
possible to increase the temperature of the condensed water to 100
degrees C. or more at short times. Therefore, it is possible to
increase the rate of increasing the temperature in the casting mold
to the temperature to solidify-harden the binder of the binder
coated refractories.
[0142] In addition, the heated gas is the heated air. Or, the
heated gas is the mixture gas comprising the water vapor mixed with
the air.
[0143] The first water vapor contains a first amount of the water.
When the heated gas is the mixture gas which comprises the water
vapor and the air, the heated gas has the second amount of the
water. In this case, the second amount of the water is lower than
the first amount of the water.
[0144] In addition, the refractory aggregate comprises at least one
of silica sand, pit sand, alumina sand, olivine sand, chromite
sand, zircon sand, mullite sand, and artificial sand. Consequently,
it is possible to manufacture the casting mold with binder coated
refractories having the fire resistance.
[0145] It is preferred that the sugar group is at least one of
monomeric sugar, oligosaccharides and polysaccharides.
Consequently, as well as preventing the emission of the gas which
pollutes the environment, the casting mold is manufactured.
[0146] In addition, as indicated in the examples 10 to 13, the
binder coated refractories is manufactured by the following coating
step. Firstly, heating the refractory aggregate is performed. Then,
adding the thermosetting resin to the refractory aggregates which
are heated is performed. Then, mixing the heated refractory
aggregate with the thermosetting resin is performed. Consequently,
the mixture of the refractory aggregate with the thermosetting
resin is provided. With respect to the mixture, adding the sugar
group dissolved in and dispersed to the water is performed. Then,
kneading the mixture and the sugar group is performed. Then, the
mixture and the sugar group are dried.
[0147] It is noted that the coating step preferably comprises the
step of adding the thermosetting resin to the refractory aggregate
having the temperature range from 50 degrees C. or more to 180
degrees C. or less. In addition, the coating step more preferably
comprises the step of adding the thermosetting resin to the
refractory aggregate having the temperature range from 110 degrees
C. or more to 180 degrees C. or less. In addition, it is more
preferred that the coating step comprises the step of adding the
thermosetting resin to the refractory aggregate having the
temperature range from 130 degrees C. or more to 140 degrees C. or
less.
[0148] In addition, thus manufactured binder coated refractories
has the following structure. The binder coated refractories ideally
has the structure that each the refractory aggregate is coated at
its surface with the thermosetting resin. In addition, the
thermosetting resin is coated at its surface with the sugar
group.
[0149] With the coating of the sugar group, the casting mold is
manufactured as follows. Firstly, the binder coated refractories
are supplied to the casting flask. Then, the water vapor is
supplied into the casting flask. Consequently, the water vapor
swells the sugar group. As a result, the sugar group has the sticky
paste condition. The sugar groups having the sticky paste condition
are in contact with each other. Therefore, the binder coated
refractories are adhered to each other, primarily. Then, the phenol
resin is melt. Consequently, the phenol resins coating the
refractory aggregates are adhered to each other, secondarily.
Consequently, the binder coated refractories are coupled with each
other, secondarily. Then, the heated gas is supplied into the
casting flask. The heated gas has the temperature which is set to
be equal to or higher than the temperature sufficient to
solidify-harden the binder. Therefore, the phenol resin is
solidified-hardened. Then, the heated gas extracts the water from
the sugar group in the sticky paste condition. In this manner, the
casting mold having the high strength is manufactured.
[0150] In addition, the casting mold manufactured according to this
method has the refractory aggregates which are each coated with the
phenol resin. Furthermore, the phenol resin is coated with the
sugar group. Therefore, if the gas is emitted from the heated
phenol resin, the sugar group prevents the gas from emitting from
the casting mold. Therefore, the casting mold emits little harmful
gas which pollutes the environment. Thus, as well as preventing the
emission of the gas polluting the environment, the casting mold is
manufactured.
[0151] In addition, thus manufactured casting mold also has the
sugar group which is located in the outermost position of the
coating layer. Therefore, the sugar group of the binder which
couples the refractory aggregates of the casting mold is thermally
decomposed at the comparatively-low temperature. So, when pouring
the high-temperature molten metal into the casting mold, the sugar
group is easily thermally decomposed by the heat of the molten
metal. Therefore, it is possible to easily break the casting mold
by the heat of the molten metal. Namely, the casting mold is easily
demolded from the casting flask without applying the impact and
without applying the heat for a long period of time to decompose
the binder. Therefore, it is possible to easily demold the cast
metal from the casting mold.
[0152] It is noted that the coating layer may have the phenol resin
and the sugar group which are mixed with each other. In contrast,
the coating layer may have the first layer and the second layer
which coats the first layer. In this case, the first layer is made
of the phenol resin, and the second layer is made of the sugar
group. When the binder coated refractories of the above is used,
the strength of the casting mold is improved. Further, despite the
use of the phenol resin, the emission of the harmful gas from the
binder coated refractories and the casting mold is prevented.
[0153] Specifically, in the example 10, 11, 12, 13, and 17, the
binder coated refractories has the refractory aggregate and the
coating layer. The refractory aggregate is coated with the coating
layer. The coating layer comprises the sugar group and the phenol
resin. The sugar group has the solid form. The phenol resin also
has the solid form. Firstly, the binder coated refractories is
filled in the casting flask. Then, the water vapor is supplied into
the casting flask. Consequently, the binder coated refractories is
exposed to the water vapor. When the water vapor is applied to the
binder coated refractories, the sugar group which coats the surface
of the refractory aggregate absorbs the water in the water vapor.
Consequently, the sugar group is swelled and has the sticky paste
condition. The sugar group having the sticky paste condition has a
strong adhesive force. Therefore, the sugar group having the sticky
paste condition still coats the surface of the refractory
aggregate. Then, the binder coated refractories are adhered to each
other with the sugar group having the sticky paste condition. Then,
the binder coated refractories is heated. In heating the binder
coated refractories, supplying "the heated air" or "the mixture gas
which has the heated air mixed with the water vapor" into the
casting flask is performed. According to heating the binder coated
refractories, the refractory aggregate, the sugar group having the
sticky paste condition, and the phenol resin are heated.
Consequently, the binder coated refractories are adhered to each
other by the phenol resin. However, the phenol resin is heated.
Therefore, the phenol resin generates a little amount of the phenol
or formaldehyde. However, the refractory aggregate is provided at
its surface with the sugar group having the sticky paste condition.
The sugar group in the sticky paste condition has the water.
Therefore, the phenol and the formaldehyde are dissolved in the
water of the sugar group in the sticky paste condition, whereby the
phenol and the formaldehyde are kept in the water. Therefore, in
the early phase of heating the binder coating refractory, the
generation of the phenol and the formaldehyde is prevented. Then,
for the sake of extracting the water from the sugar group in the
sticky paste condition, "the heated air" or "the mixture air having
the heated air with the water vapor" is supplied to the binder
coated refractories to heat the binder coated refractories.
Consequently, the water in the sugar group having the sticky paste
condition is evaporated. As the water in the sugar group
evaporates, the phenol and the formaldehyde dissolved in the water
is emitted to the atmosphere. However, the sugar group has
adsorption effect. Therefore, the phenol or the formaldehyde is
adsorbed to the sugar group. In this manner, the sugar group
prevents the phenol and the formaldehyde from being emitted out of
the casting mold. That is to say, the method of manufacturing the
casting mold makes it possible to produce the casting mold having a
high strength. Furthermore, the method of manufacturing the casting
mold makes it possible to reduce an amount of the phenol and the
formaldehyde emitted to the outside of the casting mold.
[0154] In addition, as the examples 19 to 24 indicates, this
invention discloses the method of manufacturing the casting mold
using the binder coated refractories which comprises the refractory
aggregate and the coating layer. The refractory aggregate has the
fire resistance. The refractory aggregate is coated at its surface
with the solid-state coating layer which has the sugar group which
acts as the binder. In the method of manufacturing the casting
mold, the filling step comprises the solidification-hardening step.
In the filling step, filling the binder coated refractories into
the casting flask is performed. In the solidification-hardening
step, supplying the moisture into the casting flask is performed.
Consequently, the binder gets wet. In addition, the sugar group has
the sticky paste condition. Then, supplying the superheated steam
into the casting flask to heat the binder coated refractories is
performed. Consequently, the coating layers are
solidified-hardened. Consequently, the binder coated refractories
are coupled with each other.
[0155] Therefore, the sugar group of the coating layer gets wet and
gets the sticky paste condition. Then, the superheated steam is
supplied to solidify-harden the sugar group. As a result, the
binder coated refractories in the casting flask are uniformly
heated to the high temperature, wholly. Therefore, the wet in the
casting flask is forced out of the casting flask. Consequently, the
high bending strength is applied to the casting mold. Furthermore,
the binders are solidified-hardened with each other. Therefore, the
casting mold having the surface with the high strength is
produced.
[0156] In addition, the examples 19 to 24 use the saturated water
vapor. However, there is a need to only supply the moisture into
the casting mold. That is, there is no need to supply the saturated
water vapor to supply the water into the casting mold. Therefore,
it is possible to perform the step of "supplying the water
sufficient to provide the moisture to the binder" and then
"supplying the superheated steam". That is, it is possible to
supply the water into the casting flask, directly, or to supply the
mist as the water into the casting flask.
* * * * *