U.S. patent application number 10/465751 was filed with the patent office on 2003-11-13 for process for producing molded article.
This patent application is currently assigned to KAO CORPORATION.. Invention is credited to Hashimoto, Ryoichi, Kiuchi, Kazuhiko, Miyamoto, Kenichi, Mori, Masahiro, Nomura, Takayuki, Okubo, Makoto.
Application Number | 20030209826 10/465751 |
Document ID | / |
Family ID | 14752787 |
Filed Date | 2003-11-13 |
United States Patent
Application |
20030209826 |
Kind Code |
A1 |
Okubo, Makoto ; et
al. |
November 13, 2003 |
Process for producing molded article
Abstract
A process for producing a molded article comprised of
polyurethane is provided, comprising the steps of pouring or
injecting a liquid molding material into a mold under the condition
that the contact angle between the liquid molding material and the
inner surface of the mold is adjusted to not more than 30.degree.
by applying the surface-treating agent to the inner surface of the
mold, and curing the liquid molding material. A surface-treating
agent is also provided which reduces the contact angle between the
liquid molding material and a flat plate made of the same material
as the mold to not more than 30.degree.. when the surface-treating
agent is applied to the flat plate and the liquid molding material
is dropped thereon.
Inventors: |
Okubo, Makoto;
(Wakayama-shi, JP) ; Kiuchi, Kazuhiko;
(Wakayama-shi, JP) ; Hashimoto, Ryoichi;
(Wakayama-shi, JP) ; Nomura, Takayuki;
(Wakayama-shi, JP) ; Mori, Masahiro;
(Wakayama-shi, JP) ; Miyamoto, Kenichi;
(Wakayama-shi, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
KAO CORPORATION.
|
Family ID: |
14752787 |
Appl. No.: |
10/465751 |
Filed: |
June 20, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10465751 |
Jun 20, 2003 |
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09674149 |
Oct 27, 2000 |
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6607687 |
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09674149 |
Oct 27, 2000 |
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PCT/JP99/02259 |
Apr 27, 1999 |
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Current U.S.
Class: |
264/41 ;
264/331.19; 264/338 |
Current CPC
Class: |
B29C 33/64 20130101;
B29C 67/246 20130101; B29C 33/60 20130101 |
Class at
Publication: |
264/41 ; 264/338;
264/331.19 |
International
Class: |
B29C 067/20; C08J
005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 28, 1998 |
JP |
10/119095 |
Claims
1. A process for producing a molded article made of a polyurethane
comprising, (A) pouring or injecting a liquid molding material into
a mold under the condition that the contact angle between the
liquid molding material and the inner surface of the mold is
adjusted to not more than 30.degree. by applying the
surface-treating agent to the inner surface of the mold, and (B)
curing the liquid molding material.
2. The process according to claim 1, wherein the molded article is
a shoe sole made of a polyurethane foam.
3. The process according to claim 1, wherein the contact
angle-reducing substance is an ester prepared from a fatty acid and
a monohydric alcohol.
4. The process according to claim 1, wherein the contact angle
between the liquid molding material and the inner surface of the
mold is adjusted to not more than 23.degree..
5. The process according to claims 1, wherein a mold releasing
agent is applied to the inner surface of the mold prior to pouring
or injecting the liquid molding material in the mold.
6. A surface-treating agent used for applying the surface-treating
agent to the inner surface of the mold in a process for producing a
molded article comprising pouring or injecting a liquid molding
material into a mold and curing the liquid molding material,
comprising a contact angle-reducing substance which reduces the
contact angle between the liquid molding material and a flat plate
made of the same material as the mold to not more than 30.degree.,
when the surface-treating agent is applied to the flat plate and
the liquid molding material is dropped thereon.
7. The surface-treating agent of claim 6, wherein the molded
article is a shoe sole made of a polyurethane foam.
8. A method for reducing surface voids during molding, comprising
using the surface-treating agent as defined in claim 6.
9. A method for reducing surface voids during molding, comprising
using the surface-treating agent as defined in claim 7.
Description
TECHNICAL FIELD
[0001] The present invention is directed to a process for producing
a molded article, and more particularly to a process for producing
a molded article, capable of producing a molded article having a
shape accurately corresponding to the shape of an inner surface of
a mold, and a surface-treating agent used in the process.
BACKGROUND ART
[0002] When a molded article is produced by pouring or injecting a
liquid molding material into a mold, and curing the liquid molding
material, a mold releasing agent has been hitherto applied to the
inner surface of the mold in order to easily release a molded
article from the mold.
[0003] However, when a mold releasing agent is applied to the inner
surface of a mold having a complicated shape on its inner surface,
and a molded article is produced, the surface properties of the
molded article are sometimes deteriorated because so-called surface
void, i.e. surface defect caused by insufficient filling of the
liquid starting materials and/or foams into the mold having a
complicated shape on its inner surface is generated.
[0004] An object of the present invention is to provide a process
for producing a molded article, capable of producing a molded
article having a shape accurately corresponding to the shape of an
inner surface of a mold, without the generation of defects which
lower the surface properties of a molded article, such as surface
void on the surface of the molded article.
[0005] The above and other objects of the present invention will be
apparent from the following description.
DISCLOSURE OF INVENTION
[0006] The present invention is directed to the following:
[0007] [1] a process for producing a molded article comprising,
[0008] (A) pouring or injecting a liquid molding material into a
mold in the presence of a surface-treating agent comprising a
contact angle-reducing substance under the condition that the
contact angle between the liquid molding material and the inner
surface of the mold is not more than 30.degree., and
[0009] (B) curing the liquid molding material;
[0010] [2] a surface-treating agent used in a process for producing
a molded article comprising pouring or injecting a liquid molding
material into a mold and curing the liquid molding material,
comprising a contact angle-reducing substance which reduces the
contact angle between the liquid molding material and a flat plate
made of the same material as the mold to not more than 30.degree.,
when the liquid molding material containing the surface-treating
agent is dropped on the flat plate, or when the surface-treating
agent is applied to the flat plate and the liquid molding material
is dropped thereon;
[0011] [3] a method for reducing surface voids during molding,
comprising using the above surface-treating agent; and
[0012] [4] use of the above surface-treating agent for reducing
surface voids.
BEST MODE FOR CARRYING OUT THE INVENTION
[0013] Typical examples of the liquid molding materials are resins
such as polyurethanes, epoxy resins, phenolic resins, polyesters,
urea resins, olefinic resins such as polyethylenes and
polypropylenes, and styrenic resins; rubbers such as natural
rubbers, isoprene rubbers, chloroprene rubbers, styrene-butadiene
rubbers, butadiene rubbers, acrylonitrile-butadiene rubbers,
ethylene-propylene rubbers, butyl rubbers, and acrylic rubbers.
[0014] The liquid molding materials can be those which are foamed
during molding to give a foamed molded article. The liquid molding
materials which give a foamed molded article include self-foamable
polyurethanes, foamable olefinic resins, foamable styrene resins,
or the like. When the olefinic resins, the styrene resins, or the
like are used, there can be employed a process comprising foaming
pre-foamed resin particles, or a process comprising impregnating a
foaming agent into those resins, and thereafter molding and foaming
the resins in a mold.
[0015] The process of the present invention exhibits excellent
effects for liquid molding materials, particularly polyurethanes,
the surface properties of which are easily deteriorated during
molding. Typical examples of the polyurethanes are, for instance,
polyether polyurethanes, polyester polyurethanes, and the like.
[0016] The starting materials for the polyurethane are not
particularly limited, and known ones can be used. It is desired
that the starting materials for the polyurethane are a polyol
solution and an isocyanate prepolymer. The polyol solution
comprises a polyol component, such as a polyether-polyol or a
polyester-polyol, a chain extender, water, a foam stabilizer (a
surfactant), and, as occasion demands, a catalyst. The isocyanate
prepolymer can be prepared from a polyol component such as a
polyether-polyol or a polyester-polyol, and a polyisocyanate
component such as methylenediphenyl diisocyanate or a modified
compound thereof. The polyether-polyol, the polyester-polyol, the
chain extender, the foam stabilizer (a surfactant), the catalyst,
the polyisocyanate component, and the isocyanate prepolymer may be
those which are known. The contact angle-reducing substance can be
contained in the isocyanate prepolymer and/or the polyol solution,
and it is desired that the contact angle-reducing substance is
contained in the isocyanate prepolymer. The content of the contact
angle-reducing substance in the isocyanate prepolymer is preferably
0.1 to 7% by weight, more preferably 0.1 to 5% by weight.
[0017] The polyurethane foam containing the contact angle-reducing
substance can be produced by reacting the polyol component with
components such as the polyisocyanate component, the isocyanate
prepolymer, and as occasion demands, water, a chain extender, a
foam stabilizer (a surfactant), a catalyst, and the like, in the
presence of the contact angle-reducing substance.
[0018] In the present invention, one of the major features resides
in that the liquid molding material is poured or injected into a
mold in the presence of a surface-treating agent comprising a
contact angle-reducing substance under the condition that the
contact angle between the liquid molding material and the inner
surface of the mold is not more than 30.degree., and the liquid
molding material is cured. When molded under this condition, there
can be exhibited an excellent effect that a molded article having a
shape accurately corresponding to the shape of the inner surface of
a mold can be produced, without the generation of surface voids in
the molded article. The reasons why this excellent effect is
exhibited are not clear, but it is presumably based on the
following. When the contact angle between the liquid molding
material and the inner surface of the mold is reduced to not more
than 30.degree., the wettability of the mold by the liquid molding
material is improved, and thereby the friction between the liquid
molding material and the mold is reduced. As a result, the liquid
molding material can flow into the mold to follow the complicated
shape of the inner surface of the mold. It is desired that the
contact angle between the liquid molding material and the inner
surface of the mold is not more than 23.degree., particularly not
more than 21.degree., from the viewpoint of the reducing surface
voids of the resulting molded article.
[0019] It is desired that the surface-treating agent comprises a
contact angle-reducing substance, which reduces the contact angle
between the liquid molding material and a flat plate made of the
same material as the mold to not more than 30.degree. when the
liquid molding material containing the surface-treating agent is
dropped on the flat plate, or when the surface-treating agent is
applied to the flat plate and the liquid molding material is
dropped thereon. When this surface-treating agent is used, surface
voids during molding can be reduced. More concretely, when the
surface-treating agent is used, there can be exhibited an excellent
effect that a molded article having a shape accurately
corresponding to the shape of the inner surface of the mold can be
easily produced without the generation of surface voids in the
resulting molded article. The reasons why this excellent effect is
exhibited are not clear, but it is presumably based on the
following. The wettability of the mold by the liquid molding
material is improved by the surface-treating agent, and thereby the
friction between the liquid molding material and the mold is
reduced. As a result, the liquid molding material can flow into the
mold to follow the complicated shape of the inner surface of the
mold. It is desired that the contact angle between the
surface-treating agent and the inner surface of the mold is not
more than 23.degree., particularly not more than 21.degree..
[0020] The contact angle can be determined in accordance with the
following procedures.
[0021] 1) The measurement atmosphere is kept windless at 25.degree.
C. and 55% RH.
[0022] 2) As the flat plate made of the same material as the mold,
an aluminum plate [average roughness Ra: 0.2-0.4 .mu.m] is
horizontally arranged. Thereafter, a silicone mold releasing agent
is sprayed on its surface, and sufficiently wiped off with a waste
cloth.
[0023] 3) A given surface-treating agent is uniformly sprayed in
the amount of 10 g/m.sup.2 on the silicone mold releasing
agent-sprayed surface (surface-treating agents which are solid at
25.degree. C. are previously heated to a temperature not lower than
their melting points to melt and then sprayed).
[0024] 4) The liquid molding material previously degassed by
evacuation is collected with a syringe, and one droplet is dropped
on the flat plate from the height of 10 cm from the surface of the
flat plate in a manner so that the droplet of the liquid molding
material has the weight of 0.10.+-.0.02 g.
[0025] 5) The time at which the droplet reaches the surface of the
flat plate is counted as zero second. The change of the droplet is
observed in accordance with the passage of time from the sideways
direction of the droplet with a microscope as a CCD camera. After
60 seconds passed, the contact angle between the droplet and the
flat plate is measured.
[0026] Examples of the contact angle-reducing substance include at
least one compound selected from the group consisting of esters,
ethers and amides, each having a boiling point of not less than
50.degree. C., preferably not less than 100.degree. C. at normal
pressure, in particular a boiling point of not less than
100.degree. C. at normal pressure and a boiling point of not more
than 300.degree. C. under the pressure of 0.133 kPa. Among the
contact angle-reducing substances, those having vapor pressures of
a level which does not completely evaporate within the working
hours are preferable.
[0027] Examples of the ester having a boiling point of not less
than 50.degree. C. include alkyl stearates wherein an alcohol
residue moiety of the ester has 1 to 22 carbon atoms, such as ethyl
stearate and butyl stearate; alkyl acetates wherein an alcohol
residue moiety of the ester has 4 to 22 carbon atoms, such as decyl
acetate and octadecyl acetate; alkyl oleates wherein an alcohol
residue moiety of the ester has 1 to 22 carbon atoms, such as
methyl oleate and butyl oleate; and other alkyl esters of fatty
acids wherein the fatty acid residue moiety of the ester has an
alkyl group of 2 to 21 carbon atoms, and the alcohol residue moiety
of the ester has 1 to 22 carbon atoms, such as butyl propionate,
butyl 2-ethylhexanoate, ethyl decanoate and methyl linoleate. Those
esters can be used alone or in an admixture thereof. Among them,
from the viewpoints of imparting an excellent effect of suppressing
generation of surface voids to a resulting molded article and thus
improving its appearance (design), alkyl esters of fatty acids,
formed from a fatty acid and a monohydric alcohol, such as ethyl
stearate, butyl stearate, decyl acetate, octadecyl acetate, methyl
oleate and butyl acetate, can be suitably used. Further, it is
desired that the fatty acid has 2 to 22 carbon atoms, preferably 2
to 18 carbon atoms, and that the monohydric alcohol has 1 to 22
carbon atoms, preferably 1 to 18 carbon atoms. Moreover, it is
desired that the total number of carbon atoms of the fatty acid and
the monohydric alcohol is 10 to 40, preferably 12 to 36. In
addition, from the viewpoint of yellowing resistance of the
resulting molded article, alkyl esters of saturated fatty acids,
such as butyl stearate and octadecyl acetate, can be particularly
suitably used.
[0028] The ester having a boiling point of not less than 50.degree.
C. may be a symmetric ether or asymmetric ether. Examples thereof
include dioctyl ether, dibutyl ether, dihexyl ether, didecyl ether,
butyl hexyl ether, and the like. Those esters may be used alone or
in an admixture thereof. Among them, from the viewpoints of
imparting an excellent effect of suppressing generation of surface
voids to a resulting molded article and thus improving its
appearance (design), dioctyl ether, and the like can be suitably
used.
[0029] The content of the contact angle-reducing substance in the
surface-treating agent may be appropriately adjusted so that the
contact angle between the liquid molding material and the flat
plate is reduced to not more than 30.degree., preferably not more
than 23.degree., more preferably not more than 21.degree..
Incidentally, the contact angle-reducing substance itself can be
solely used as the surface-treating agent, since the contact angle
between the liquid molding material and the flat plate can be
reduced to not more than 30.degree., even when the contact
angle-reducing substance is used alone as the surface-treating
agent.
[0030] The surface-treating agent may contain a mold releasing
agent such as a silicone compound or a wax as occasion demands, in
addition to the contact angle-reducing substance. The
surface-treating agent containing the contact angle-reducing
substance and the mold releasing agent can be desirably used by
applying it to the inner surface of the mold during the production
of various molded articles because this surface-treating agent
suppresses the generation of surface voids, and improves the
appearance (design) of the molded article.
[0031] The silicone compound can be suitably used in the present
invention because the silicone compound is excellent in liquidity
and releasing properties, and moreover is durable for repetitious
use. Typical examples of the silicone compound include dimethyl
silicone oil, and modified silicone oils such as alkyl-modified
silicone oils and higher fatty acid-modified silicone oils, or
those diluted with a solvent, those prepared into aqueous
emulsions, and the like. Concretely, there can be cited dimethyl
silicone oil having a viscosity of 30 to 5000 mm.sup.2/s at
25.degree. C. Those silicone compounds can be used alone or in an
admixture thereof.
[0032] The wax can be suitably used because it is inexpensive.
Examples of the wax include mineral oils, olefinic waxes, paraffin
waxes, and the like. Those waxes can be used alone or in admixture
thereof. Among them, the mineral oils and paraffin waxes each
having a molecular weight of not less than 300 are preferable.
[0033] Among the mold releasing agents, the silicone compounds are
more preferable from the viewpoint of the releasing property.
[0034] The content of the mold releasing agent in the
surface-treating agent cannot be absolutely determined because it
differs depending upon their kinds. However, it is desired that the
content is usually not less than 5% by weight, preferably not less
than 10% by weight, more preferably not less than 30% by weight,
from the viewpoint of exhibiting sufficient releasing properties.
Also, it is desired that the content is not more than 95% by
weight, preferably not more than 90% by weight, from the viewpoint
of exhibiting sufficient surface properties.
[0035] The surface-treating agent can be applied to the inner
surface of the mold, or it can be contained in the liquid molding
material.
[0036] When the surface-treating agent is applied to the inner
surface of the mold, an outsole of shoe soles made of a
polyurethane foam having complicated shapes particularly in the
bottom surface can be formed in a shape exactly conforming to the
mold without the generation of defects which impair the surface
properties of the molded article, such as surface void.
[0037] The method for applying the surface-treating agent to the
inner surface of the mold includes, for instance, a method of
coating, spraying, dipping, or the like, without limiting the
present invention to those methods above.
[0038] When the surface-treating agent is applied to the inner
surface of the mold, the mold is filled with the liquid molding
material thereafter, and can be molded under given molding
conditions suitable for the kinds of the liquid molding material,
and the like. It is desired that the amount of the surface-treating
agent applied to the inner surface of the mold is 3 to 30 g/m.sup.2
from the viewpoints of imparting sufficient surface properties to a
resulting molding article and preventing cracking and dulling of
the surface.
[0039] When the surface-treating agent is contained in the liquid
molding material, a midsole of shoe soles, made of a polyurethane
foam and particularly having a complicated shape in the side
surfaces can be molded in a shape exactly conforming to the mold
without the generation of the defects which impair the surface
properties of the molded article, such as surface void.
[0040] When the surface-treating agent is contained in the liquid
molding material, the content of the surface-treating agent in the
liquid molding material differs depending upon the kinds of the
liquid molding material. However, it is desired that the content is
adjusted so that the contact angle between the liquid molding
material and the flat plate made of the same material as the mold
is not more than 30.degree.. For instance, it is desired that the
content of the contact angle-reducing substance in the liquid
molding material is 0.05 to 3.5% by weight, preferably 0.25 to 1%
by weight.
[0041] When the surface-treating agent is contained in the liquid
molding material, the liquid molding material is filled in the
mold, and can be molded under given molding conditions suitable for
the kinds of the liquid molding material.
[0042] The materials of the mold which can be used in the present
invention are not particularly limited. Examples of such materials
include iron, stainless steel, copper, aluminum, aluminum alloys,
epoxy resins, phenolic resins, and the like. In addition, the
shapes of the inner surface of the mold are not particularly
limited, and any arbitrary shape can be selected as long as the
inner surface has a shape well corresponding to the shape of the
desired molded article.
[0043] When the liquid molding material is molded in a mold, it is
desirable to previously apply a mold releasing agent to the inner
surface of the mold by means of coating, spraying, dipping, or the
like in order to improve its releasing property. The mold releasing
agent includes dimethyl silicone oil, mineral oils, paraffin waxes,
and the like, without intending to limit the present invention to
those exemplified above.
[0044] Thus, a molded article having a given shape can be obtained
by molding and subsequent demolding. The resulting molded article
has excellent surface properties because the generation-of harmful
defects such as surface void is suppressed even when the molded
article has a complicated shape in its inner surface.
[0045] Especially, when the molded article is a molded article made
of a polyurethane foam, the above-mentioned effects are exhibited
even more excellently. Particularly, the above effects are even
more remarkably exhibited for the polyurethane foam for shoe soles
having complicated shapes in the bottom surface or side
surfaces.
[0046] In general, the shoe soles can be classified into outsoles
used in sandals and men's shoes, and midsoles used in sports shoes.
The effects according to the present invention can be remarkably
exhibited particularly in midsoles used within a low density
region.
[0047] From the viewpoint of reducing surface voids, the density of
the polyurethane foam is preferably not less than 0.15 g/cm.sup.3
and less than 0.30 g/cm.sup.3, and more preferably not less than
0.20 g/cm.sup.3 and less than 0.30 g/cm.sup.3.
PREPARATION EXAMPLE 1
[0048] (Preparation of Liquid Molding Material for Polyether
Polyurethane Foam)
[0049] In a mixer (Model "DH-2.5," manufactured by Tokushu Kika
Kogyo K. K.) were previously stirred 50 parts by weight of a polyol
solution [trade name: "EDDYFOAM AS-2045," manufactured by Kao
Corporation], comprising polypropylene glycol, a chain extender,
water and a foam stabilizer (a surfactant), and 50 parts by weight
of an isocyanate prepolymer [trade name: "EDDYFOAM B-6009N,"
manufactured by Kao Corporation], main constituents of which were
polypropylene glycol and 4,4-diphenylmethane diisocyanate, and the
resulting mixture was evacuated in a desiccator.
[0050] The resulting liquid mixture was used to measure a contact
angle in accordance with the following method for measurement of a
contact angle. As a result, the contact angle was found to be
43.degree..
[0051] The viscosity of this liquid mixture gradually increases.
Therefore, the time period from the previous stirring of the polyol
solution and the isocyanate prepolymer to the measurement of the
contact angle was adjusted to four minutes.
PREPARATION EXAMPLE 2
[0052] (Preparation of Liquid Molding Material for Polyester
Polyurethane Foam)
[0053] In a mixer (Model "DH-2.5," manufactured by Tokushu Kika
Kogyo K. K.) were previously stirred 50 parts by weight of a polyol
solution [trade name: "EDDYFOAM AS-1210U," manufactured by Kao
Corporation], comprising a polyester-polyol, a chain extender,
water and a foam stabilizer (a surfactant), and 50 parts by weight
of an isocyanate prepolymer [trade name: "EDDYFOAM B-2009,"
manufactured by Kao Corporation], main constituents of which were a
polyester-polyol and 4,4-diphenylmethane diisocyanate, and the
resulting mixture was evacuated in a desiccator.
[0054] The resulting liquid mixture was used to measure a contact
angle in accordance with the following method for measurement of a
contact angle. As a result, the contact angle was found to be
46.degree..
[0055] The viscosity of this liquid mixture gradually increases.
Therefore, the time period from the previous stirring of the polyol
solution and the isocyanate prepolymer to the measurement of the
contact angle was adjusted to four minutes.
[0056] [Measurement of Contact Angle]
[0057] 1) The measurement atmosphere is kept windless at 25.degree.
C. and 55% RH.
[0058] 2) As the flat plate made of the same material as the mold,
an aluminum plate [average roughness Ra: 0.2-0.4 .mu.m] is
horizontally arranged. Thereafter, a silicone mold releasing agent
[trade name: "PURAPOWER 2060," manufactured by Kao Corporation] is
sprayed on its surface, and sufficiently wiped off with a waste
cloth.
[0059] 3) A given surface-treating agent is uniformly sprayed in
the amount of 10 g/m.sup.2 on the silicone mold releasing
agent-sprayed surface (surface-treating agents which are solid at
25.degree. C. are previously heated to a temperature of not lower
than their melting points to melt and then sprayed).
[0060] 4) The liquid molding material previously degassed by
evacuation is collected with a syringe [Model "SS-02S,"
manufactured by TERUMO CORPORATION], and one droplet is dropped on
the flat plate from the height of 10 cm from the surface of the
flat plate in a manner so that the droplet of the liquid molding
material has the weight of 0.10.+-.0.02 g.
[0061] 5) The time at which the droplet reaches the surface of the
flat plate is counted as zero second. The change of the droplet is
observed in accordance with the passage of time from the sideways
direction of the droplet with a microscope [Product No. "VH-6200,"
manufactured by KEYENCE CORPORATION] as a CCD camera. After 60
seconds passed, the contact angle between the droplet and the flat
plate is measured.
EXAMPLES 1 TO 4 AND COMPARATIVE EXAMPLES 1 TO 4
[0062] [Production of Molded Articles Made of Polyether
Polyurethane Foam]
[0063] There was used a mold for testing made of aluminum having an
inner surface for forming on the tiptoe portion a sole pattern
having 127 projections for antislipping wherein each of their
height, width and length is about 5 mm, respectively, and wherein
each vertical cross section of the projections was triangular. The
temperature of the mold was adjusted to 50.degree..+-.2.degree. C.
A mold releasing agent (trade name: "PURAPOWER 2060," manufactured
by Kao Corporation) was sprayed on the inner surface, and wiped off
with a waste cloth.
[0064] A surface-treating agent shown in Table 1 was used, and
sprayed on the mold releasing agent-sprayed surface with a spray
gun so that the amount of the surface treatment agent applied was
10 g/m.sup.2. The contact angle between the liquid molding material
and the surface-treating agent-sprayed surface was measured in
accordance with the above method for measurement of a contact
angle. The results are shown in Table 1.
[0065] One tank of a pouring-type low-pressure foaming machine was
charged with an isocyanate prepolymer [trade name: "EDDYFOAM
B-6009N," manufactured by Kao Corporation], and the liquid
temperature was adjusted to 40.degree. C., and the other tank
thereof was charged with a liquid mixture prepared by mixing 100
parts by weight of a polyol composition solution [trade name:
"EDDYFOAM AS-2045," manufactured by Kao Corporation] and 2 parts by
weight of a catalyst [trade name: "EDDYFOAM AS-651-60C,"
manufactured by Kao Corporation], and the liquid temperature was
adjusted to 40.degree. C.
[0066] The isocyanate prepolymer was admixed with the liquid
mixture, and the resulting mixture was stirred using this
low-pressure foaming machine, so that an isocyanate index was 98.
The resulting mixture was poured into the mold mentioned above to
allow foaming. After 5 minutes passed from the pouring, the foamed
product was taken out from the mold, to give a molded article made
of a polyurethane foam. Each of the resulting molded articles had a
density of about 0.65 g/cm.sup.3 and hardness (Asker C) of
80.+-.2.
[0067] Next, the shape transfer ratio of the resulting molded
article made of a polyurethane foam was evaluated in accordance
with the following method. The results are shown in Table 1.
[0068] [Shape Transfer Ratio]
[0069] In order to determine whether or not a molded article having
a shape accurately corresponding to the shape of the inner surface
of the mold is obtained, the shape transfer ratio was obtained in
accordance with the following method.
[0070] The case where not less than 50% of the projections for
antislipping of the molded article was lacked at its tip portion
was evaluated as Score -3, and the number of the lacked projections
is defined as "p"; the case where not less than 30% and less than
50% of the projections for antislipping of the molded article was
lacked at its tip portion was evaluated as Score -2, and the number
of the lacked projections is defined as "q"; the case where less
than 30% of the projections for antislipping of the molded article
was lacked at its tip portion was evaluated as Score -1, and the
number of the lacked projections is defined as "r"; and the case
where no lacked portions were observed was evaluated as Score 0,
and the number of no lacked projections is defined as "s" (the
total number of p+q+r+s is 127. The shape transfer ratio was
calculated in accordance with the following equation:
[Shape Transfer
Ratio]=[381+(-3).times.p+(-2).times.q+(-1).times.r+0.times-
.s].div.3.81
EXAMPLES 5 TO 8 AND COMPARATIVE EXAMPLES 5 TO 8
[0071] [Production of Molded Articles Made of Polyester
Polyurethane Foam]
[0072] The same procedures as in Examples 1 to 4 were carried out
except that an isocyanate prepolymer [trade name: "EDDYFOAM
B-2009," manufactured by Kao Corporation], and 100 parts by weight
of a polyol solution [trade name: "EDDYFOAM AS-1210," manufactured
by Kao Corporation] and 1.5 parts by weight of a catalyst [trade
name: "EDDYFOAM AS-651-60C," manufactured by Kao Corporation],
instead of the isocyanate prepolymer, the polyol solution and the
catalyst used in Examples 1 to 4, to produce a molded article made
of a polyurethane foam. Each of the resulting molded articles had a
density of about 0.60 g/cm.sup.3 and hardness (Asker C) of
80.+-.2.
[0073] The shape transfer ratio of the resulting molded article
made of a polyurethane foam was evaluated in the same manner as
above. The results are shown in Table 1.
1TABLE 1 Contact Angle Shape Kind of Composition of Sur- after
Transfer Example Polyurethane face-Treating Agent 60 sec Ratio No.
Foam (% by weight) (.degree. C.) (%) Example 1 Ether Butyl stearate
(100) 18 93.5 Polyurethane 2 Ether Ethyl stearate (100) 17 94.6
Polyurethane 3 Ether Octadecyl (100) 17 95.5 Polyurethane stearate
4 Ether Dioctyl ether (100) 17 97.7 Polyurethane Comp. Ex. 1 Ether
None 43 34.9 Polyurethane 2 Ether EMULGEN (100) 32 50.3
Polyurethane 903*.sup.1 3 Ether Linseed oil (100) 31 57.5
Polyurethane 4 Ether Lard (100) 31 44.6 Polyurethane Example 5
Ester Butyl stearate (100) 21 86.3 Polyurethane 6 Ester Ethyl
stearate (100) 23 83.6 Polyurethane 7 Ester Octadecyl (100) 22 83.6
Polyurethane stearate 8 Ester Dioctyl ether (100) 22 90.2
Polyurethane Comp. Ex. 5 Ester None 46 30.3 Polyurethane 6 Ester
EMULGEN (100) 34 46.3 Polyurethane 903*.sup.1 7 Ester Linseed oil
(100) 34 53.3 Polyurethane 8 Ester Lard (100) 35 42.1 Polyurethane
(Note) *.sup.1Trade name, manufactured by Kao Corporation
[0074] As is clear from the results shown in Table 1, it can be
seen that all of the molded articles obtained in each Example have
extremely high shape transfer ratios of because a contact
angle-reducing substance showing a contact angle of not more than
30.degree. is used.
EXAMPLES 9 TO 20 AND COMPARATIVE EXAMPLES 9 TO 12
[0075] [Production of Molded Articles Made of Polvether
Polyurethane Foam]
[0076] The same procedures as in Examples 1 to 4 were carried out
except that spraying of the mold releasing agent on the mold for
testing was omitted and that surface-treating agents shown in Table
2, which were previously admixed together at 25.degree. C., were
used, to produce a molded article made of a polyurethane foam. Each
of the resulting molded articles had a density of about 0.65
g/cm.sup.3 and hardness (Asker C) of 80.+-.2.
[0077] The releasing property after production of the molded
article made of a polyurethane foam was evaluated in accordance
with the following method. The shape transfer ratio of the
resulting molded article made of a polyurethane foam was evaluated
in the same manner as above. The results are shown in Table 2.
[0078] [Releasing Property after Production]
[0079] The condition when taking out the resulting molded article
from the mold was determined based on the following criteria:
2 .circleincircle.: the molded article not being entirely stuck to
the inner surface of the mold at all; .smallcircle.: the molded
article being slightly stuck to the inner surface of the mold
without posing any problems; and x: the molded article being stuck
to the mold, thereby making it impossible to take out the molded
article from the mold.
EXAMPLES 21 AND 22
[0080] [Production of Molded Articles Made of Polyester
Polyurethane Foam]
[0081] The same procedures as in Examples 5 to 8 were carried out
except that spraying of the mold releasing agent on the mold for
testing was omitted and that the surface-treating agents shown in
Table 2, which were previously admixed together at 25.degree. C.
were used, to produce a molded article made of a polyurethane foam.
Each of the resulting molded articles had a density of about 0.65
g/cm.sup.3 and hardness (Asker C) of 80.+-.2.
[0082] The releasing property after production and the shape
transfer ratio of the resulting molded article made of a
polyurethane foam were evaluated in the same manner as above. The
results are shown in Table 2.
[0083] In Table 2, the following mold releasing agents were used:
Mold releasing agent A: [trade name: "SUPER OIL B," manufactured by
NOF Corporation]; Mold releasing agent B: dimethyl silicone oil
[trade name: "TSF-451-50," manufactured by Toshiba Silicone Co.,
Ltd.]; Mold releasing agent C: dimethyl silicone oil [trade name:
"TSF-451-300," manufactured by Toshiba Silicone Co., Ltd.]; Mold
releasing agent D: a blend of silicone compounds [trade name:
"PURAPOWER 20conc 60," manufactured by Kao Corporation].
3TABLE 2 Releas- Shape Kind of Composition of Sur- ing Transfer
Example Polyurethane face-Treating Agent Proper- Ratio No. Foam (%
by weight) ty (%) Example 9 Ether Butyl stearate (10)
.circleincircle. 70.3 Polyurethane Mold releasing (90) agent A 10
Ether Butyl stearate (20) .circleincircle. 95.0 Polyurethane Mold
releasing (80) agent A 11 Ether Butyl stearate (50)
.circleincircle. 96.3 Polyurethane Mold releasing (50) agent A 12
Ether Butyl stearate (80) .smallcircle. 92.5 Polyurethane Mold
releasing (20) agent A 13 Ether Butyl stearate (20) .smallcircle.
92.3 Polyurethane Mold releasing (80) agent A 14 Ether Butyl
stearate (20) .circleincircle. 96.3 Polyurethane Mold releasing
(80) agent B 15 Ether Butyl stearate (20) .circleincircle. 92.8
Polyurethane Mold releasing (80) agent C 16 Ether Butyl stearate
(20) .circleincircle. 89.3 Polyurethane Mold releasing (80) agent D
17 Ether Dioctyl ether (20) .smallcircle. 93.6 Polyurethane Mold
releasing (80) agent A 18 Ether Dioctyl ether (20) .circleincircle.
98.5 Polyurethane Mold releasing (80) agent B 19 Ether Dioctyl
ether (20) .circleincircle. 95.3 Polyurethane Mold releasing (80)
agent C 20 Ether Dioctyl ether (20) .circleincircle. 91.6
Polyurethane Mold releasing (80) agent D Comp. Ex. 9 Ether Mold
releasing (100) .circleincircle. 33.6 Polyurethane agent A 10 Ether
Mold releasing (100) .circleincircle. 35.6 Polyurethane agent B 11
Ether Mold releasing (100) .circleincircle. 38.3 Polyurethane agent
C 12 Ether Mold releasing (100) .circleincircle. 34.2 Polyurethane
agent D Example 21 Ester Butyl stearate (20) .circleincircle. 83.3
Polyurethane Mold releasing (80) agent A 22 Ester Dioctyl ether
(20) .circleincircle. 84.6 Polyurethane Mold releasing (80) agent
A
[0084] As is clear from the results shown in Table 2, it can be
seen that each of the molded articles made of a polyurethane foam
obtained in each Example has an extremely high shape transfer
ratio, and also has excellent releasing properties after molding
because the contact angle-reducing substance showing a contact
angle of not more than 30.degree. is used.
EXAMPLES 23 TO 26 AND COMPARATIVE EXAMPLES 13 TO 15
[0085] There was used a mold made of aluminum having a shape
corresponding to a molded article having a length of 255 mm, a
width of 90 mm, a height of 30 mm, and a thickness of 5 mm, and
also having 20 projections wherein each of length, width, and
height is 20 mm, 20 mm, and 2 mm, respectively, as a design of its
side surface. The temperature of the mold was adjusted to
70.degree..+-.2.degree. C. A mold releasing agent (trade name:
"PURAPOWER 2060," manufactured by Kao Corporation) was sprayed on
the inner surface, and wiped off with a waste cloth.
[0086] A contact angle-reducing substance shown in Table 3 was
added to an isocyanate prepolymer [trade name: "EDDYFOAM B-3021,"
manufactured by Kao Corporation]. One tank of a pouring-type
low-pressure foaming machine was charged with the resulting
mixture, and the liquid temperature was adjusted to 35.degree. C.
The other tank thereof was charged with a liquid mixture prepared
by mixing 100 parts by weight of a polyol solution [trade name:
"EDDYFOAM AS-6-52U," manufactured by Kao Corporation], 1.3 parts by
weight of a catalyst [trade name: "EDDYFOAM AS-651-60C,"
manufactured by Kao Corporation], 2 parts by weight of a
crosslinking agent [trade name: "EDDYFOAM AS-60E," manufactured by
Kao Corporation], 0.5 parts by weight of a foam stabilizer (a
surfactant) [trade name: "EDDYFOAM AS-11S," manufactured by Kao
Corporation], and the liquid temperature was adjusted to 40.degree.
C.
[0087] The isocyanate prepolymer was admixed with the liquid
mixture and stirred using this low-pressure foaming machine so that
an isocyanate index was 100. The resulting mixture was poured into
the mold mentioned above to allow foaming. After 5 minutes passed
from the pouring, the foamed product was taken out from the mold,
to give a molded article made of a polyurethane foam. Each of the
resulting molded articles had a density of about 0.28 g/cm.sup.3
and hardness (Asker C) of 60.+-.2.
[0088] Next, the shape transfer ratio of the resulting molded
article made of a polyurethane foam was evaluated in accordance
with the following method. The results are shown in Table 3.
[0089] When the upper portion of the projections is lacked in the
length of not less than 2 mm during the molding of the molded
article, its length is measured, and a sum (T) of length of all
surface voids is calculated, and the shape transfer ratio is
calculated from the following equation:
Shape Transfer Ratio=(400+T).div.400.times.100
[0090] The evaluation is made on the following criteria:
4 [Criteria] .smallcircle.: the transfer ratio being not less than
95 (extremely excellent appearance); .DELTA.: the transfer ratio
being not less than 92.5 and less than 95 (good appearance); and x:
the transfer ratio being less than 92.5 (poor appearance).
[0091]
5TABLE 3 Contact Angle- Reducing Substance Evaluation of and Amount
Thereof Shape Transfer Example [Content in Isocyanate Pre- Ratio
No. polymer (% by weight)] (%) Example 23 Butyl stearate (0.5)
.smallcircle. 24 Butyl stearate (1) .smallcircle. 25 Butyl stearate
(5) .smallcircle. 26 Ethyl stearate (1) .smallcircle. Comp. Ex. 13
Octyl phthalate (1) x 14 Octyl phthalate (5) x 15 None x
[0092] As is clear from the above results shown in Table 3, it can
be seen that all of the molded articles made of a polyurethane foam
obtained in Examples 23 to 26 have high shape transfer ratios
because the contact angle-reducing substance is added thereto.
[0093] Industrial Applicability
[0094] According to the process of the present invention, there can
be exhibited an effect that a molded article having a shape
accurately corresponding to the shape of the inner surface of the
mold can be produced without the generation of lowering surface
properties such as surface void on the surface of the molded
article.
[0095] Therefore, the process of the present invention can be
suitably employed when producing a molded article used, for
instance, for shoe soles.
* * * * *