U.S. patent application number 11/632207 was filed with the patent office on 2008-08-28 for heat generating body and process for producing heat generating body.
This patent application is currently assigned to MYCOAL PRODUCTS CORPORATION. Invention is credited to Toshihiro Dodo.
Application Number | 20080202490 11/632207 |
Document ID | / |
Family ID | 35783986 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080202490 |
Kind Code |
A1 |
Dodo; Toshihiro |
August 28, 2008 |
Heat Generating Body and Process For Producing Heat Generating
Body
Abstract
There is provided a heat generating body which by forming a
temporary adhering part upon temporary adhesion between a substrate
and a heat generating composition molded body and a covering
material with an adhesive layer and subsequent heat sealing,
realizes higher line speed, thereby largely improving the
productivity, does not generate position deviation of the heat
generating composition molded body in welding the substrate and the
covering material, is able to be heat sealed and is free from seal
failure. A heat generating body as formed by laminating a heat
generating composition molded body resulting from molding of a heat
generating composition containing, as essential components, an
exothermic substance, a carbon component, a reaction accelerator
and water and having a water mobility value of from 0.01 to 20 on a
substrate, covering by a covering material and heat sealing the
periphery of the heat generating composition molded body, is
characterized in that the substrate and the covering material are
temporarily adhered with a sticky layer, the temporarily adhered
portion is heat sealed with a heat seal layer which the substrate
and/or the covering material has, the sticky layer component and
the heat seal layer component are co-present in the heat seal part,
and the heat seal part has a seal strength at 60.degree. C. of 0.8
kg/25 mm or more.
Inventors: |
Dodo; Toshihiro; (Kanagawa,
JP) |
Correspondence
Address: |
KRATZ, QUINTOS & HANSON, LLP
1420 K Street, N.W., Suite 400
WASHINGTON
DC
20005
US
|
Assignee: |
MYCOAL PRODUCTS CORPORATION
Tochigi-shi
JP
|
Family ID: |
35783986 |
Appl. No.: |
11/632207 |
Filed: |
July 14, 2005 |
PCT Filed: |
July 14, 2005 |
PCT NO: |
PCT/JP2005/013003 |
371 Date: |
February 15, 2008 |
Current U.S.
Class: |
126/263.07 ;
126/204; 53/477; 53/479 |
Current CPC
Class: |
A61F 2007/0098 20130101;
C09K 5/18 20130101; F24V 30/00 20180501; A61F 7/034 20130101; A61F
2007/0268 20130101 |
Class at
Publication: |
126/263.07 ;
126/204; 53/477; 53/479 |
International
Class: |
F24J 1/00 20060101
F24J001/00; B65B 51/16 20060101 B65B051/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 14, 2004 |
JP |
2004-207831 |
Claims
1. A heat generating body as formed by laminating a heat generating
composition molded body resulting from molding of a heat generating
composition containing, as essential components, an exothermic
substance, a carbon component, a reaction accelerator and water and
having a water mobility value of from 0.1 to 20 on a substrate,
covering by a covering material and heat sealing the periphery of
the heat generating composition molded body, characterized in that:
the substrate and the covering material are temporarily adhered
with a sticky layer, the temporarily adhered portion is heat sealed
with a heat seal layer which the substrate and/or the covering
material has, the sticky layer component and the heat seal layer
component are co-present in the heat seal part, and the heat seal
part has a seal strength at 60.degree. C. of 0.8 kg/25 mm or
more.
2. The heat generating body according to claim 1, characterized in
that at least a part of the heat seal part has a region having an
air vent part heat sealed therein.
3. The heat generating body according to claim 1, characterized in
that, the sticky layer is constituted of a hot melt based
adhesive.
4. The heat generating body according to claim 1, characterized in
that the total thickness of the heat seal layer is the thickness of
the sticky layer or more.
5. The heat generating body according to claim 1, characterized in
that the sticky layer has a thickness of from 0.1 to 100 .mu.m.
6. The heat generating body according to claim 1, characterized in
that the sticky layer has a void.
7. The heat generating body according to claim 1, characterized in
that a mixed part of the heat seal layer component and the adhesive
layer component is present in the heat seal part.
8. The heat generating body according to claim 1, characterized in
that the substrate and the covering material are formed of an
extensible raw material.
9. The heat generating body according to claim 1, characterized in
that the heat generating composition molded body is sectioned by a
sectioned part which is a heat seal part and is disposed in a
plural number.
10. The heat generating body according to claim 1, characterized in
that the exothermic substance in the heat generating composition
comprising iron powder particles, and the iron powder particles
have iron oxide film.
11. The heat generating body according to claim 1, characterized in
that the heat generating composition molded body is compression
treated.
12. The heat generating body according to claim 1, characterized in
that after heat sealing, at least a part of the heat generating
composition molded body is moved into the temporary adhering part
which is not heat sealed, thereby deadhering the temporary adhering
part which is not heat sealed.
13. The heat generating body according to claim 1, characterized in
that the heat generating body has a fixing measure on the exposed
surface thereof.
14. A process for producing a heat generating body, characterized
in that an air-permeable substrate and/or covering material at
least has a heat sealable heat seal layer; a heat generating
composition molded body resulting from molding of a heat generating
composition containing, as essential components, an iron powder, a
carbon component, a reaction accelerator and water and having a
water mobility value of from 0.01 to 20 is laminated on the
substrate; a hot melt based adhesive is provided as a sticky layer
thereon by a melt blow system; the covering material is covered
thereon; the heat generating composition molded body and/or the
substrate is temporarily adhered to the covering material by
temporary adhesion rolls; the periphery of the heat generating
composition molded body is then heat sealed; and the seal part has
a seal strength at 60.degree. C. of 0.8 kg/25 mm or more.
15. The process for producing a heat generating body as according
to claim 14, characterized in that after temporarily adhering the
outer circumference of the heat generating body, the outer
circumstance of the heat generating body is heat sealed while
retaining an air vent part.
16. The process for producing a heat generating body according to
claim 14, characterized in that heat sealing is achieved by using
heat rolls having the heat seal part smaller than the temporary
adhering part in the temporary adhesion rolls.
17. The process for producing a heat generating body according to
claim 14, characterized in that the heat generating composition
molded body is moved into the temporary adhering part which is not
heat sealed, thereby deadhering the temporary adhering part which
is not heat sealed.
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat generating body
which upon temporary adhesion of a substrate and a covering
material with an adhesive layer and subsequent heat sealing, is
able to be surely heat sealed without generating wrinkles, realizes
higher line speed, thereby largely improving the productivity and
is free from seal failure and to a process for producing the
same.
BACKGROUND ART
[0002] In recent years, there have been proposed heat generating
bodies having a heat generating composition sealed in a bag body in
which at least one surface thereof is made of a air-permeable film
(or a sheet) and thermal wet packs in which an adhesive layer is
laminated on one surface of a heat generating body, thereby
enabling to be stuck to a human body or the like. As so-called
throwaway body warmers and thermal wet packs, there have also been
proposed ones utilizing a warming measure or a medical hot pack and
ones utilizing a so-called percutaneous absorption system in which
an adhesive layer of such a thermal wet pack or a sticking agent
contains or supports a percutaneously absorptive drug.
[0003] As a process for producing such a heat generating body, in
general, a heat generating composition is thrown down in a
prescribed region on the upper surface of an air-permeable or
airtight substrate, an airtight or air-permeable covering material
is then covered thereon, and thereafter, the periphery of the
substrate and the periphery of the covering material are entirely
heat sealed. Namely, the peripheries of the substrate and the
covering material are entirely heat sealed.
[0004] In this case, there may be the case where a hot melt based
bonding agent layer is laminated on either one of the substrate or
the covering material and this hot melt based bonding agent layer
is mediated.
[0005] Furthermore, as another process for producing such a heat
generating body, in general, a heat generating composition is
thrown down in a prescribed region on the upper surface of an
air-permeable or airtight substrate, an airtight or air-permeable
covering material is then covered thereon, and thereafter, the
outer periphery of the substrate and the outer periphery of the
covering material are entirely compression sealed via a sticky
layer. Namely, the outer peripheries of the substrate and the
covering material are entirely compression sealed (sealed with an
adhesive).
[0006] Then, for the purpose of inhibiting an exothermic reaction
until the time of use, the thus produced heat generating body is
sealed and stored within an airtight outer bag and then provided
for distribution.
[0007] In these conventional heat generating bodies, in the case
where the outer peripheries of the substrate and the covering
material are entirely heat sealed, there are encountered the
following problems.
[0008] That is, in the case where by using a synthetic resin film
which constitutes the substrate or the covering material or a hot
melt based bonding agent layer which is formed in advance on at
least one surface of the substrate or the covering material, the
surroundings of the substrate and the covering material are heat
sealed by heat fusion or heat bonding, for the purpose of
preventing the heat generating composition from incorporation into
the heat seal part, it is required to surely achieve heat fusion or
heat bonding after melting the foregoing synthetic resin film or
hot melt based bonding agent. Therefore, a limit for realizing high
speed is generated, resulting in a lowering of the
productivity.
[0009] Furthermore, in the case where a heat generating composition
molded body is laminated on a substrate, a covering material is
covered thereon, and the surroundings of the heat generating
composition molded boy are heat sealed by heat fusion or heat
bonding, there is some possibility that the heat generating
composition molded body moves between the substrate and the
covering material, thereby causing seal failure. In particular,
such becomes remarkable at the time of high speed. Thus, even when
lamination could have been achieved at a high speed, sealing could
be achieved only at a low speed. As a result, it had to accept
low-speed production as a whole of the step. In particular, in the
case the volume of the heat generating composition molded body is
small and a seal width is small, such became especially remarkable,
resulting in an extra-low speed.
[0010] On the other hand, in an example where the surroundings of a
substrate and the periphery of a covering material are adhesive
sealed by using an adhesive layer, sealing can be simply achieved,
and a heat generating body in which the seal portion, namely the
entire surroundings of the heat generating body are flexible can be
prepared. However, according to the foregoing adhesive sealing, a
seal strength is lowered depending upon the utility at the time of
using the heat generating body, the heat generation due to seal
separation becomes instable so that there is created an anxiety
such a burn. Thus, its use and utility were limited. Even when a
temperature lower than the melting point of the adhesive layer is
partially applied to achieve warm treatment and sealing, there was
encountered a problem such that its effect is not so high, seal
separation occurs and seal failure is caused, thereby causing
abnormal heat generation.
[0011] As a matter of course, there are encountered exactly the
same problems in the sticking agent to be used in this conventional
heat generating body.
DISCLOSURE OF THE INVENTION
Problems that the Invention is to Solve
[0012] An object of the invention is to solve the foregoing
technical problems and to provide a heat generating body which by
forming a temporary adhering part upon temporary adhesion between a
substrate and a heat generating composition molded body and a
covering material with an adhesive layer and subsequent heat
sealing, realizes higher line speed, thereby largely improving the
productivity, does not generate position deviation of the heat
generating composition molded body in welding the substrate and the
covering material, is able to be heat sealed and is free from seal
failure.
Means for Solving the Problems
[0013] As set forth in claim 1, a heat generating body of the
invention is a heat generating body as formed by laminating a heat
generating composition molded body resulting from molding of a heat
generating composition containing, as essential components, an
exothermic substance, a carbon component, a reaction accelerator
and water and having a water mobility value of from 0.01 to 20 on a
substrate, covering by a covering material and heat sealing the
periphery of the heat generating composition molded body, which is
characterized in that:
[0014] the substrate and the covering material are temporarily
adhered with a sticky layer, the temporarily adhered portion is
heat sealed with a heat seal layer which the substrate and/or the
covering material has, the sticky layer component and the heat seal
layer component are co-present in the heat seal part, and the heat
seal part has a seal strength at 60.degree. C. of 0.8 kg/25 mm or
more.
[0015] Also, a heat generating body as set forth in claim 2 is
characterized in that in the heat generating body as set forth in
claim 1, at least a part of the heat seal part has a region having
an air vent part heat sealed therein.
[0016] Also, a heat generating body as set forth in claim 3 is
characterized in that in the heat generating body as set forth in
claim 1, the sticky layer is constituted of a hot melt based
adhesive.
[0017] Also, a heat generating body as set forth in claim 4 is
characterized in that in the heat generating body as set forth in
claim 1, the total thickness of the heat seal layer is the
thickness of the sticky layer or more.
[0018] Also, a heat generating body as set forth in claim 5 is
characterized in that in the heat generating body as set forth in
claim 1, the sticky layer has a thickness of from 0.1 to 100
.mu.m.
[0019] Also, a heat generating body as set forth in claim 6 is
characterized in that in the heat generating body as set forth in
claim 1, the sticky layer has a void.
[0020] Also, a heat generating body as set forth in claim 7 is
characterized in that in the heat generating body as set forth in
claim 1, a mixed part of the heat seal layer component and the
adhesive layer component is present in the heat seal part.
[0021] Also, a heat generating body as set forth in claim 8 is
characterized in that in the heat generating body as set forth in
claim 1, the substrate and the covering material are formed of an
extensible raw material.
[0022] Also, a heat generating body as set forth in claim 9 is
characterized in that in the heat generating body as set forth in
claim 1, the heat generating composition molded body is sectioned
by a sectioned part which is a heat seal part and is disposed in a
plural number.
[0023] Also, a heat generating body as set forth in claim 10 is
characterized in that in the heat generating body as set forth in
claim 1, the exothermic substance in the heat generating
composition comprising iron powder particles, and the iron powder
particles have iron oxide film.
[0024] Also, a heat generating body as set forth in claim 11 is
characterized in that in the heat generating composition molded
body is compression treated.
[0025] Also, a heat generating body as set forth in claim 12 is
characterized in that in the heat generating body as set forth in
claim 1, after heat sealing, at least a part of the heat generating
composition molded body is moved into the temporary adhering part
which is not heat sealed, thereby deadhering the temporary adhering
part which is not heat sealed.
[0026] Also, a heat generating body as set forth in claim 13 is
characterized in that in the heat generating body as set forth in
claim 1, the heat generating body has a fixing measure on the
exposed surface thereof.
[0027] As set forth in claim 14, a process for producing a heat
generating body of the invention is characterized in that an
air-permeable substrate and/or covering material at least has a
heat sealable heat seal layer; a heat generating composition molded
body resulting from molding of a heat generating composition
containing, as essential components, an iron powder, a carbon
component, a reaction accelerator and water and having a water
mobility value of from 0.01 to 20 is laminated on the substrate; a
hot melt based adhesive is provided as a sticky layer thereon by a
melt blow system; the covering material is covered thereon; the
heat generating composition molded body and/or the substrate is
temporarily adhered to the covering material by temporary adhesion
rolls; the periphery of the heat generating composition molded body
is then heat sealed; and the seal part has a seal strength at
60.degree. C. of 0.8 kg/25 mm or more.
[0028] Also, a process for producing a heat generating body as set
forth in claim 15 is characterized in that in the process for
producing a heat generating body as set forth in claim 14, after
temporarily adhering the outer circumstance of the heat generating
body, the outer circumference of the heat generating body is heat
sealed while retaining an air vent part.
[0029] Also, a process for producing a heat generating body as set
forth in claim 16 is characterized in that in the process for
producing a heat generating body as set forth in claim 14, heat
sealing is achieved by using heat rolls having the heat seal part
smaller than the temporary adhering part in the temporary adhesion
rolls.
[0030] Also, a process for producing a heat generating body as set
forth in claim 17 is characterized in that in the process for
producing a heat generating body as set forth in claim 14, the heat
generating composition molded body is moved into the temporary
adhering part which is not heat sealed, thereby deadhering the
temporary adhering part which is not heat sealed.
[0031] Also, it is preferable that in the heat generating body, the
central part of the heat seal part is heat sealed, and the
surroundings of the heat seal part are adhesive sealed.
[0032] Also, it is preferable that in the heat generating body, the
sticky layer is laminated on the heat seal layer of the covering
material.
[0033] Also, it is preferable that in the heat generating body, the
sticky layer is laminated on the upper surface of the heat
generating composition molded body.
[0034] Also, it is preferable that in the heat generating body, the
melting point of a base polymer of the adhesive which constitutes
the sticky layer is not higher than the melting point of a heat
seal material which constitutes the heat seal layer.
[0035] Also, it is preferable that in the heat generating body, the
fixing measure is an adhesive layer, and the adhesive layer
contains at least one member selected from additional components
consisting of a water retaining agent, a water absorptive polymer,
a pH adjusting agent, a surfactant, an organosilicon compound, a
hydrophobic polymer compound, a pyroelectric substance, an
antioxidant, an aggregate, a fibrous substance, a moisturizer, a
functional substance, and a mixture thereof.
[0036] Also, it is preferable that in the heat generating body, the
thickness of the sticky layer is not more than the total thickness
of the respective heat seal layers of the substrate and the
covering material.
[0037] Also, it is preferable that in the heat generating body, the
sticky layer has a void.
[0038] Also, it is preferable that in the heat generating body, the
heat seal layer is constituted of an ethylene based heat seal
material, and the sticky layer is constituted of a hot melt based
adhesive layer.
[0039] Also, it is preferable that in the process for producing a
heat generating body, the temporary adhesion roll is a die roll
and/or a flat roll in which at least the surface thereof is
flexible.
[0040] Also, it is preferable that in the process for producing a
heat generating body, a pushing roll having a pushing part smaller
than the heat generating composition molded body is used.
[0041] Also, it is preferable that in the process for producing a
heat generating body, the heat generating composition molded body
is moved along a collapsing plate.
ADVANTAGES OF THE INVENTION
[0042] The invention brings the following effects.
1. In the heat generating body according to the invention, upon
temporary adhesion of a substrate and a covering material with a
sticky layer and subsequent heat sealing, it is possible to surely
achieve heat sealing without generating wrinkles and realize
high-speed heat sealing. 2. In the case of sealing the substrate
and the covering material in this way, not only it is only required
to apply a pressure, but also heat fusion as in the conventional
art is not needed. Accordingly, it is not necessary to think of any
influence of thermal conduction of the substrate or covering
material, the movement of a heat generating composition laminate
can be easily prevented from occurring, and sealing can be surely
achieved by next heat sealing. Thus, the seal failure is prevented
so that the reliability of the heat generating body is remarkably
improved. 3. In addition, since the heat generating body is
constituted such that the substrate and the covering material are
adhered with a sticky layer, the both can be temporarily adhered
extremely easily only by applying a pressure, and next heat sealing
can be easily achieved. As a result, higher line speed is realized,
and the productivity is remarkably improved. 4. In addition, by
employing, as the sticky layer, a layer which is compatible with a
heat sealable layer, an adhesive and a heat seal material are well
mixed without causing separation at the time of heat sealing,
whereby it has become possible to achieve heat sealing more
surely.
BEST MODES FOR CARRYING OUT THE INVENTION
[0043] The heat generating body of the invention is a heat
generating body as formed by laminating a heat generating
composition molded body resulting from molding of a heat generating
composition containing, as essential components, an exothermic
substance, a carbon component, a reaction accelerator and water and
having a water mobility value of from 0.01 to 20 on a substrate,
covering by a covering material and heat sealing the periphery of
the heat generating composition molded body, wherein the substrate
and the covering material are temporarily adhered with a sticky
layer, the temporarily adhered portion is heat sealed with a heat
seal layer which the substrate and/or the covering material has,
the sticky layer component and the heat seal layer component are
co-present in the heat seal part, and the heat seal part has a seal
strength at 60.degree. C. of 0.8 kg/25 mm or more.
[0044] The invention designs to realize high speed of heat sealing
and to seal stabilize the heat seal part, thereby bringing the
following advantages.
1) Since the heat generating body is constituted such that the
substrate and the covering material are adhered with a sticky
layer, the both can be temporarily adhered extremely easily only by
applying a pressure. As a result, the invention is very suitable
for temporary adhesion for the purpose of realizing higher line
speed. 2) Also, a heat seal device is not required so that
simplification of production facilities can be realized. Moreover,
in the case of carrying out heat fusion by heat sealing or heat
bonding using a hot melt based bonding agent, while a heat source
is necessary, since in adhesive sealing, the substrate and the
covering material are sealed with an adhesive layer, a heat source
such as electric power becomes unnecessary, thereby economizing on
energy. As a result, it becomes possible to achieve temporary
adhesion of the heat generating body or thermal sticking agent
extremely economically. 3) When temporary adhesion of the
surroundings of the substrate and the covering material is carried
out with a sticky layer in this way, the heat generating
composition molded body interposed between the substrate and the
covering material does not cause deviation and can be moved to a
next step at high speed. 4) In the case where the substrate and the
covering material are heat sealed, since the movement of the heat
generating composition molded body is controlled by temporary
adhesion, it is possible to carry out heat sealing while following
the movement of the surfaces of the heat seal rolls. 5) Since the
adhesive which is used in the sticky layer is well compatible with
the hot melt based bonding agent to be used for heat sealing, it is
dispersed in the heat seal part so that it does not hinder heat
sealing. Thus, an appropriate heat seal part can be formed. 6)
Since the substrate and the covering material are brought into
intimate contact with each other by temporary adhesion via the
sticky layer, the heat seal part can be easily formed by heat
sealing. Thus, it has become possible to achieve stable heat
sealing at a high speed of 20 m/min or more, an aspect of which was
difficult so far.
[0045] The "temporary adhesion" as referred to in the invention
means weak pressure-sensitive bonding or adhesion for the purpose
of holding the accommodated heat generating composition molded body
until at least the substrate and the covering material are adhered
to each other via a sticky layer and heat sealed.
[0046] Furthermore, the sticky layer is constituted of an adhesive
and has a seal strength at 60.degree. C. of from 0.01 to 0.8 kg/25
mm. In this way, the movement of the heat generating composition
molded body between the substrate and the covering material can be
stopped, thereby making it possible to carry out high-speed heat
sealing. In addition, if desired, the temporary adhesion may be
carried out under warming. It is preferable that the warming is
carried out by a treatment under pressure at a temperature of not
higher than the melting point of a base polymer in a hot melt based
adhesive which forms the sticky layer.
[0047] Though the temporarily adhered seal part is formed via the
sticky layer, the adhesive which constitutes the sticky layer is
not limited so far as it is a layer formed of a polymer composition
which is tacky at the ordinary temperature and can achieve heat
sealing after temporary adhesion.
[0048] Furthermore, the adhesive which constitutes the sticky layer
to be used for temporary adhesion is preferably a non-hydrophilic
adhesive. It is preferable that the adhesive which constitutes the
sticky layer is well compatible with the heat seal material which
constitutes the heat seal and that the melting point of a base
polymer of the adhesive is not higher than the melting point of the
heat seal material. In particular, the holt melt based bonding
agent is preferably a hot melt based adhesive. Furthermore, in the
case where the heat seal material is an olefin based raw material,
an olefin based adhesive is enumerated as a preferred example of
the adhesive.
[0049] Prior to the formation of the temporary adhering part of the
invention, it is preferable that an adhesive is laminated on the
substrate, the heat generating composition molded body, or the
covering material. It is especially preferable that an adhesive
which is well compatible with the heat seal layer is laminated on
the periphery of at least the heat generating composition molded
body on the substrate and/or the periphery of at least the heat
generating composition molded body beneath the covering
material.
[0050] That is, there are enumerated the case where a sticky layer
is laminated on the periphery of the heat generating composition
molded body on the substrate and/or the periphery of the heat
generating composition molded body beneath the covering material;
the case where a sticky layer is laminated on the entire surface on
the substrate and/or the entire surface beneath the covering
material; the case where a sticky layer is laminated on the entire
surface on the substrate and/or the periphery of the heat
generating composition molded body beneath the covering material;
the case where a sticky layer is laminated on the periphery of the
heat generating composition molded body on the substrate and/or the
entire surface beneath the covering material; and the case where
such a sticky layer is partially laminated on the entire surfaces
of the respective places. Furthermore, in the foregoing respective
cases, an adhesive layer may be interspersed entirely or partially
on the heat generating composition molded body.
[0051] In addition, in the case where a sticky layer is laminated
on the periphery of the heat generating composition molded body on
the substrate and/or the periphery of the heat generating
composition molded body beneath the covering material, the sticky
layer may be partially interspersed on the whole of a site from
which the sticky layer is eliminated in the substrate and/or the
covering material, namely over a corresponding region where the
heat generating composition molded body is laminated.
[0052] The "seal strength at 60.degree. C." as referred to herein
means an average value of respective maximum values obtained by
subjecting three samples to a measurement by taking a specimen of
25 mm.times.250 mm from a place of a subjective sealed sample to be
measured for the seal strength, allowing the specimen to stand
under circumstances at 60.degree. C. for 5 minutes, grasping it
under circumstances at 60.degree. C., and measuring a maximum
strength at intervals of 10 mm and at a tensile speed of 300
mm/min. The seal strength of the temporary adhering part is
preferably 0.5 kg/25 mm or more, more preferably from 0.5 to 1
kg/25 mm, further preferably from 0.5 to 0.9 kg/25 mm, and still
further preferably from 0.5 to 0.8 kg/25 mm under circumstances at
20.degree. C.; and the seal strength at 60.degree. C. is preferably
less than 0.8 kg/25 mm, more preferably 0.01 kg/25 mm or more but
less than 0.8 kg/25 mm, further preferably 0.01 kg/25 mm or more
but less than 0.5 kg/25 mm, and still further preferably 0.01 kg/25
mm or more but less than 0.4 kg/25 mm.
[0053] The sticky layer of the temporary adhering part is
constituted of an adhesive, has a seal strength at 60.degree. C. of
from 0.01 to 0.8 kg/25 mm, is able to stop the movement of the heat
generating composition molded body between the substrate and the
covering material, and makes it possible to achieve high-speed heat
seal. In addition, if desired, warming may be carried out at the
time of temporary adhesion. It is preferable that the warming is
carried out under pressure at a temperature of not higher than a
melting point of a base polymer in a hot melt based adhesive for
forming the adhesive layer.
[0054] The seal strength under circumstances at 20.degree. C. of
the heat seal part which has been heat sealed after the temporary
adhesion is preferably 1.0 kg/25 mm or more, more preferably 1.2
kg/25 mm or more, further preferably 1.5 kg/25 mm or more, and
still further preferably from 1.5 to 3 kg/25 mm. Furthermore, the
seal strength at 60.degree. C. under circumstances at 60.degree. C.
is preferably 0.8 kg/25 mm or more, more preferably 1.0 kg/25 mm or
more, further preferably 1.2 kg/25 mm or more, and still further
preferably 1.5 kg/25 mm or more. Here, the condition of the seal
strength under circumstances at 20.degree. C. is identical with
that of the seal strength at 60.degree. C., except that the
circumferential temperature for the measurement is 20.degree.
C.
[0055] The range where the temporary adhering part is provided is
not limited. The contact bonding surface may be any of partial
contact bonding or entire contact bonding.
[0056] Furthermore, though its measure is not limited, too, the
contact bonding can be preferably carried out by using a die plate
or a planar or flat plate. Furthermore, the contact bonding can
also be carried out by passing through die rolls or planar or flat
rolls. The die rolls are constituted such that in order that only
the temporary adhering part is contact bonded, the contact bonding
part is formed in a contact bonding shape which is substantially
similar to the periphery of the heat generating composition molded
body; or that the contact bonding part is formed in such a manner
that the a part of the surroundings of the heat generating
composition molded body is contact bonded, whereas the heat
generating composition molded body is not contact bonded. In other
words, there is no limitation so far as the heat generating
composition molded body is not contact bonded. Though the contact
bonding surface may be a plain surface, taking into account
slipperiness of a raw material or transportation, it is preferable
that at least one surface of the contact bonding surface is an
embossed surface. The shape of embossing is not particularly
limited. Usually, examples thereof include a wavy form, a hexagonal
form, a ring-like form, a polka-dotted form, and a reticulate form.
A rate of the area of projections on the embossed surface is not
particularly limited. Usually, it is preferably from 0.5 to 60%.
Furthermore, the contact bonding part may be provided partially or
entirely against the temporary adhering part. The planar or flat
rolls are one which is made of a flexible raw material and
temporarily adheres at least the periphery of the heat generating
composition molded body while applying a pressure to the whole of
the heat generating body. The foregoing raw material is not limited
so far as it can be deformed and temporarily adhered. Examples
thereof include an expanded body, a felt, a woven fabric, a
non-woven fabric, a rubber, and a balloon body.
[0057] Furthermore, the temporary adhesion is carried out by using
a temporary adhering tool, examples of which are shown in FIGS. 7
to 13. However, the temporary adhering tool is not limited, but any
tool can be used so far as it is able to achieve the temporary
adhesion. In particular, in the case where the heat generating
composition molded body is thick, it is preferred to temporarily
adhere at least one member selected from a heat generating
composition molded body and a substrate end part as shown in FIG. 8
depending upon the kind of a covering material to be used. The
"substrate end part" as referred to herein means an end part of the
substrate parallel to the MD direction of the heat generating
composition molded body and a region which is parallel to the TD
direction and in which the heat generating composition molded body
is not present.
[0058] Furthermore, the temporary adhesion may be achieved by
providing a sagging of the covering material between at least one
heat generating composition molded body and at least one adjacent
heat generating composition molded body. The sagging at the time of
temporary adhesion may be provided in one direction or plural
directions. This is because cutting in seal can be prevented by a
gentle sagging.
[0059] Furthermore, it is possible to embody a thin-width heat seal
part by combining temporary adhesion, heat sealing and the movement
of a heat generating composition at a higher speed. In the case
where an exothermic part is constituted of a sectional exothermic
part and a sectioned part which is the seal part, when the
formation of the sectioned part is achieved only by heat sealing,
it was required to make the sectioned part large positioned between
a sectional exothermic part and a sectional exothermic part due to
a critical width of the heat seal. However, when the space between
a sectional exothermic part and a sectional exothermic part becomes
large, a heat insulation effect between the sectional exothermic
parts is reduced so that the exothermic time becomes short.
Accordingly, this method for softening the heat generating body
involved a problem in view of the exothermic duration. By employing
a combination of temporary adhesion, heat sealing and the movement
of the heat generating composition according to the invention, when
heat sealing is carried out after the temporary adhesion, it
becomes possible to form a thin-width heat seal part at high speed
without scattering the heat generating composition into the heat
seal part; and after forming the heat seal part, by using a pushing
roll, etc., the heat generating composition is moved into a region
which is the temporary adhering part but is not heat sealed, the
non-heat seal part is deadhered, thereby making it possible to make
the width of the sectioned part small. In this way, it has become
possible to embody a flexible heat generating body without
shortening the exothermic duration of the heat generating body.
[0060] In the invention, as a heat seal material constituting a
heat seal layer, a single raw material may be used, or a composite
raw material having a heat seal layer may be used. The heat seal
material is not limited so far as at least a part thereof can be
welded upon heating. Examples thereof include hot melt based resins
such as polyolefins (for example, polyethylene and polypropylene)
or olefin copolymer resins, ethylene based hot melt resins (for
example, ethylene-vinyl acetate copolymer resins and
ethylene-acrylic acid ester copolymer resins (for example,
ethylene-isobutyl acrylate copolymer resins)), polyamide based hot
melt resins, butyral based hot melt resins, polyester based hot
melt resins, polyamide based hot melt resins, polyester based hot
melt resins, polymethyl methacrylate based hot melt resins,
polyvinyl ether based hot melt resins, polyurethane based hot melt
resins, polycarbonate based hot melt resins, such as polyvinyl
acetate, and vinyl chloride-vinyl acetate copolymers; and films or
sheets thereof. Furthermore, in these hot melt based resins or
films or sheets thereof, ones having various additives (for
example, an antioxidant) compounded therein can be used. In
particular, low density polyethylene and polyethylene obtained by
using a metallocene catalyst are useful.
[0061] The thickness of the heat seal layer is not limited so far
as heat sealing can be achieved. It is usually from 5 to 1,000
.mu.m, preferably from 10 to 500 .mu.m.sup.2, and more preferably
from 15 to 250 .mu.m. When the thickness of the heat seal layer is
less than 5 .mu.m, there is some possibility that a prescribed
adhesive strength is not obtained. On the other hand, when it
exceeds 1,000 .mu.m, the heat seal rate becomes slow.
[0062] The foregoing adhesive is not limited so far as it is a
layer formed of a polymer composition which is tacky at the
ordinary temperature, it is well compatible with the heat seal
layer and it can achieve heat sealing after the temporary adhesion.
Specific examples thereof include a solvent type adhesive and a hot
melt based adhesive.
[0063] Furthermore, since in the expanded adhesive layer, a gas in
the pore causes elastic deformation, elasticity, stretch-ability
and flexibility are remarkably enhanced. As a result, not only
flexibility of a packaging material made of a substrate and a
covering material, especially flexibility of a seal part between
the substrate and the covering material is remarkably enhanced, but
also a feeling for use is much more enhanced.
[0064] Examples of a method for expanding a hot melt based adhesive
include a chemical expansion method and a physical expansion
method. The chemical expansion method is a method in which an
inorganic expanding agent or an organic expanding agent or a
mixture thereof is used and expansion is carried out by utilizing a
nitrogen gas or a carbonic acid gas as generated during its
decomposition reaction; and the "physical expansion" as referred to
herein is a method in which a gas such as compressed air,
compressed nitrogen and a compressed carbonic acid gas is
incorporated into the adhesive by a physical force.
[0065] Of these expansion methods, physical expansion methods as
described in JP-B-60-3350, JP-A-62-87267, JP-B-63-17295, and
JP-A-1-59023 are especially recommended for the reasons as
described below.
[0066] That is, according to the physical expansion method, by
bringing a pressurized gas into contact with a hot melt based
adhesive to be injected in the air from a nozzle, the adhesive is
blown away in a finely fibrous state, thereby forming fine
continuous pores or closed cells.
[0067] Since its expansion ratio depends upon a temperature related
to the viscosity of the adhesive and a pressure of the pressurized
gas, it is easy to set up the temperature condition and pressure
condition for the purpose of obtaining an adhesive layer of a
prescribed expansion ratio as compared with the case of using an
expanding agent.
[0068] Furthermore, in this physical expansion method, for the
purpose of stabilizing the expansion ratio, it is only required to
stabilize an injection amount or injection rate of the adhesive
from a nozzle and a pressure of the pressurized air. Thus, it is
easy to obtain a uniform adhesive layer.
[0069] In the case of carrying out this physical expansion method,
in order to increase a control precision of the expansion ratio, it
is preferred to bring the compressed gas into contact with the
adhesive as injected from the nozzle as fast as possible.
Accordingly, for example, it is preferred to provide a gas port for
injecting the compressed gas in the surrounding of an injection
port from which the adhesive is injected, thereby bringing the
compressed gas into contact with the adhesive at the same time of
injecting the adhesive.
[0070] Furthermore, for the purpose of shortening the painting time
by simultaneously injecting the adhesive into a wide range as far
as possible, it is preferable that the injection port from which
the adhesive is injected is formed in a slit form or a number of
injection ports of the adhesive are provided adjacent to each other
in series.
[0071] Furthermore, in the invention, it is beneficial that the
adhesive is formed of a hot melt type polymer substance, an
alicyclic petroleum resin and a softening agent, and this adhesive
is expanded by the foregoing methods.
[0072] In the invention, as the hot melt type polymer substance,
those as described previously are enumerated. This hot melt type
polymer substance is a base polymer in the adhesive, and an
expanded body of the adhesive as formed by using this has excellent
shape holding properties, has initial tackiness, is good in
adhesiveness at the time of the normal temperature or at the time
of warming, and is stable with respect to adhesive strength after
the adhesion.
[0073] Furthermore, in the invention, the alicyclic petroleum resin
is a tackifier, and its combination with the hot melt type polymer
substance gives rise to prescribed adhesive characteristics.
[0074] The "alicyclic petroleum resin" as referred to herein is a
petroleum resin having a cyclic skeleton. Specific examples thereof
include rosins, dehydrated rosins, glycerin esters of a dehydrated
rosin, glycerin esters of a gum rosin, hydrogenated rosins, methyl
esters of a hydrogenated rosin, glycerin esters of a hydrogenated
rosin, pentaerythritol rosins of a hydrogenated rosin, polymerized
rosins, glycerin esters of a polymerized rosin, chroman-indene
resins, hydrogenated petroleum resins, maleic anhydride modified
rosins, rosin derivatives, and C-5 based petroleum resins. For the
purpose of imparting a prescribed adhesive strength to the sticking
agent, the petroleum resin is properly used singly or in
combination of two or more kinds thereof.
[0075] The substrate of the invention is substantially planar and
does not have an accommodating pocket; the covering material covers
the heat generating composition provided on the substrate; the
sectional exothermic part which is constituted by heat sealing the
periphery of the heat generating composition is made of two or more
plural sectional exothermic parts; the respective sectional
exothermic parts are disposed at intervals by the sectioned part
which is a heat seal part; and the exothermic part is formed of a
gathering of the foregoing sectional exothermic parts. Here, in the
invention, the substrate and the covering material are not
distinguished from each other depending upon a raw material
constitution; but a raw material on which the heat generating
composition molded body is laminated is defined as a substrate, and
a raw material which is then covered on the substrate or heat
generating composition molded body is defined as a covering
material.
[0076] The term "substantially planar" as referred to in the
invention means a planar surface not having an accommodating
concave such as an accommodating pocket, an accommodating section,
and an accommodating zone as provided in advance for the purpose of
accommodating the heat generating composition. Accordingly,
irregularities which do not intentionally accommodate the heat
generating composition may be present.
[0077] The "pocket" as referred to in the invention is an
accommodating pocket which is provided in advance for the purpose
of accommodating the heat generating composition and is a pocket as
described in JP-T-2001-507593. Since irregularities which are not
used for intentionally accommodating the heat generating
composition molded body are not the pocket, even when such
irregularities are present on a substrate, it is to be noted that
such a substrate is defined as a substantially planar
substrate.
[0078] The "accommodating section" as referred to herein is an
accommodating section for accommodation as provided in advance on
the packaging material for the purpose of accommodating the heat
generating composition and is an accommodating section as described
in Japanese Patent No. 3,161,605 and JP-T-11-508314. Since
irregularities which are not used for intentionally accommodating
the heat generating composition molded body are not the
accommodating section, even when such irregularities are present on
a substrate, it is to be noted that such a substrate is defined as
a substantially planar substrate.
[0079] The "accommodating zone" as referred to herein is an
accommodating zone for accommodation as provided in advance on the
packaging material for the purpose of accommodating the heat
generating composition and is an accommodating zone as described in
Japanese Patent No. 3,161,605 and JP-T-11-508314. Since
irregularities which are not used for intentionally accommodating
the heat generating composition molded body are not the
accommodating zone, even when such irregularities are present on a
substrate, it is to be noted that such a substrate is defined as a
substantially planar substrate.
[0080] The raw material which constitutes the substrate, the
covering material or the underlay material is not limited so far as
it functions as an accommodating bag of the heat generating
composition. Examples of the raw material include air-impermeable
raw materials, air-permeable raw materials, water absorptive raw
materials, non-water absorptive raw materials, non-extensible raw
materials, extensible raw materials, stretchable raw materials,
non-stretchable raw materials, expanded raw materials, non-expanded
raw materials, non-heat sealable raw materials, and heat sealable
raw materials. The raw material can be properly used depending upon
a desired utility in a desired form such as films, sheets,
non-woven fabrics, woven fabrics, and composites thereof.
[0081] Usually, the substrate is made of an air-impermeable film or
sheet, and the covering material is made of an air-permeable film
or sheet or non-woven fabric, and vice versa. The both may be
air-permeable. Furthermore, in the underlay material, air
permeability or air impermeability may be properly used for
different purposes.
[0082] The substrate or covering material may be of a
single-layered structure or multilayered structure, and its
structure is not limited. As examples of the multilayered
structure, the substrate is made of layer A/layer B, layer A/layer
B/layer C, or layer A/layer B/layer C/layer D; and the covering
material is made of layer F/layer G, layer E/layer F/layer G, or
layer F/layer H/layer G.
[0083] Incidentally, examples of the layer A include thermoplastic
resin films (for example, polyethylene), heat seal layers (for
example, polyethylene and EVA), and water absorptive papers;
examples of the layer B include non-woven fabrics of a
thermoplastic resin (for example, nylons), non-water absorptive
papers, water absorptive papers, thermoplastic resin films (for
example, polyethylene films, polypropylene films, polyester films,
and polyamide (for example, nylons) films), and wicks (for example,
non-water absorptive papers and water absorptive papers); examples
of the layer C include adhesive layers, non-water absorptive
papers, water absorptive papers, thermoplastic resin films (for
example, polyethylene), non-slip layers, and non-woven fabrics of a
thermoplastic resin (for example, polyesters and nylons); examples
of the layer D include separators, thermoplastic resin films (for
example, polyethylene), and non-woven fabrics; examples of the
layer E include heat seal layers; examples of the layer F include
porous films or perforated films made of a thermoplastic resin (for
example, polyethylene), films made of a thermoplastic resin (for
example, polyethylene), non-water absorptive papers, and water
absorptive papers; examples of the layer G include non-woven
fabrics of a thermoplastic resin (for example, polyesters and
nylons); and examples of the layer H include non-water absorptive
papers and water absorptive papers. Examples of the substrate or
covering material include heat seal layer made of polyethylene
obtained by using a metallocene catalyst/polyethylene film,
polyethylene-made heat seal layer/polypropylene film, heat seal
layer made of polyethylene obtained by using a metallocene
catalyst/polyethylene film/adhesive layer/separator, EVA-made heat
seal layer/polypropylene film/adhesive layer/separator,
polyethylene-made heat seal layer/polyethylene film/nylon non-woven
fabric, EVA-made heat seal layer/polyethylene film/nylon non-woven
fabric, polyethylene-made heat seal layer/polypropylene
film/polypropylene non-woven fabric, non-woven fabric/porous film,
non-woven fabric/paper, perforated (provided by a needle or laser)
film/porous film, non-woven fabric/paper, porous film/perforated
(provided by a needle or laser) film, non-woven fabric/paper, and
porous film/non-woven fabric. A method for laminating the
respective layers is not limited. The respective layers may be
directly laminated; the respective layers may be laminated via an
air-permeable adhesive layer or a laminating agent layer; and the
respective layers may be laminated by hot melt extrusion or the
like. The adhesive layer may be provided on such a packaging
material.
[0084] For example, in the case of laminating the foregoing raw
material such as non-woven fabrics and porous films via an
air-permeable sticky layer, examples of a method for forming the
air-permeable sticky layer include a method in which a sticky
substance is fibrillated by an appropriate system such as a curtain
spray system, a melt blow system, and a slot spray system for
blowing and spreading a sticky substance via hot air under heat
melting and spread and accumulated on an appropriate supporting
substrate made of a porous film, an air-permeable substrate, a
separator, etc., thereby forming a porous sticky layer.
[0085] A thickness of each of the substrate, the covering material,
the underlay material, and the raw material constituting the same
largely varies depending upon the utility and is not limited. The
thickness is usually from 5 to 5,000 .mu.m, preferably from 10 to
500 .mu.m, and more preferably from 20 to 250 .mu.m.
[0086] The air-impermeable raw material is not limited so far as it
is air-impermeable. Examples thereof include films, sheets or
coatings made of a polymer (for example, polyethylene,
polypropylene, nylons, polyacrylates, polyesters, polyvinyl
alcohols, and ethylene-vinyl acetate copolymers) and laminates
thereof with a metal (including a semiconductor) compound (for
example, silicon oxide) or composite raw materials using the
same.
[0087] Of the foregoing air-impermeable raw materials, examples of
a film having high air impermeability include films provided with a
single layer or multiple layers of a thin film having a metal
including a semiconductor or a compound thereof provided on an
air-impermeable raw material film. Examples of the metal including
a semiconductor include silicon, aluminum, and alloys or mixtures
containing such a metal. Examples of the metal (including a
semiconductor) compound include oxides, nitrides and oxynitrides of
the foregoing metals or alloys or mixtures. Examples of the layer
include silicon oxide layers, aluminum oxide layers, and silicon
oxynitride layers; layers obtained by laminating an arbitrary layer
of these layers on a stretched polyolefin film (for example, a
biaxially stretched poly-propylene film).
[0088] The air-permeable raw material is not limited so far as it
is air-permeable. Examples thereof include air-permeable films (for
example, porous films and perforated films); materials having air
permeability by themselves (for example, papers and non-woven
fabrics); materials prepared by laminating at least one of papers
and air-permeable films and non-woven fabrics so as to have air
permeability; materials prepared by providing an air-impermeable
packaging material comprising a non-woven fabric having a
polyethylene film laminated thereon with fine pores by using a
needle, etc. so as to have air permeability; non-woven fabric whose
air permeability is controlled by laminating a fiber and heat
contact bonding; porous films; and materials prepared by sticking a
non-woven fabric onto a porous film. The "perforated film" as
referred to herein is a film prepared by providing an
air-impermeable film (for example, polyethylene films) with fine
pores by using a needle so as to have air permeability.
[0089] The air permeability is not limited so far as the heat
generation can be kept. In the case of use in usual heat
generation, the air permeability is usually from 50 to 10,000
g/m.sup.2/4 hr, preferably from 70 to 5,000 g/m.sup.2/24 hr, more
preferably from 100 to 2,000 g/m.sup.2/24 hr, and further
preferably from 100 to 700 g/m.sup.2/24 hr in terms of moisture
permeability by the Lyssy method.
[0090] When the moisture permeability is less than 50, the heat
value is small and a sufficient thermal effect is not obtained, and
therefore, such is not preferable. On the other hand, when it
exceeds 10,000 g/m.sup.2/24 hr, the exothermic temperature is high
so that a problem in safety may possibly be generated, and
therefore, such is not preferable. However, there is no limitation
even when the moisture permeability exceeds 10,000 g/m.sup.2/24 hr
depending upon the utility, or even in the use at a moisture
permeability closed to the open system, according to
circumstances.
[0091] The stretchable packaging material is not particularly
limited so far as it is stretchable. That is, it is only required
that the stretchable packaging material is stretchable as a whole.
The stretchable packaging material may be formed of a single
material or a composite material of stretchable substrates or a
combination of a stretchable substrate and a non-stretchable
substrate.
[0092] Examples of the stretchable packaging material include
single materials (for example, natural rubbers, regenerated
rubbers, synthetic rubbers, elastomers, and stretchable shape
memory polymers) and mixtures thereof, mixed materials thereof with
or blended materials of such a stretchable raw material and a
non-stretchable raw material or fabrics constituted of a
combination of these materials, films, and yarns.
[0093] The porous film can be properly selected among porous films
obtained by stretching a film made of a polyolefin based resin (for
example, polyethylene, linear low density polyethylene, and
polypropylene) or a fluorine based resin (for example,
polytetrafluoroethylene) and a filler.
[0094] As the non-woven fabric, single non-woven fabrics of a
single fiber or composite fiber made of a material such as rayon,
nylons (polyamides), polyesters, polyacrylates, polypropylene,
vinylon, polyethylene, polyurethane, cupra, cotton, cellulose, and
pulp, or laminates of blended or accumulated fiber layers of such
fibers are useful. Furthermore, from the standpoint of production
process, dry non-woven fabrics, wet non-woven fabrics, spunbonds,
spunlaces, and the like can be used. Non-woven fabrics made of a
composite fiber having a core-sheath structure are also useful.
[0095] Furthermore, in the components to be used in the moldable
heat generating composition and the heat generating body of the
invention and the packaging materials such as the substrate, the
covering material and the underlay material, biodegradable raw
materials can be used in addition to conventionally employed raw
materials.
[0096] As the heat generating composition, it is preferred to use a
heat generating composition capable of causing an exothermic
reaction upon contact with air, which contains, as essential
components, an exothermic substance such as iron, a carbon
component, a reaction accelerator and water, contains surplus water
so as to have a water mobility value of from 0.01 to 20 and has
moldability due to the surplus water and in which the water in the
heat generating composition does not function as a barrier
layer.
[0097] Furthermore, it is preferable that the heat generating
composition contains at least one member selected from additional
components consisting of a water retaining agent, a water
absorptive polymer, a pH adjusting agent, a hydrogen formation
inhibitor, an aggregate, a fibrous material, a functional
substance, a surfactant, an organosilicon compound, a pyroelectric
substance, a moisturizer, a fertilizer component, a hydrophobic
polymer compound, a heat generating aid, a metal other than iron, a
metal oxide other than iron oxide, an acidic substance, and a
mixture thereof.
[0098] Incidentally, in the invention, what water does not function
as a barrier layer and causes an exothermic reaction upon contact
with air means that water in a heat generating composition does not
function as a barrier layer which is an air intercepting layer and
immediately after the production of a heat generating composition,
comes into contact with air, thereby immediately causing an
exothermic reaction.
[0099] As the "iron powder" as referred to herein, usual iron
powders, iron alloy powders and active iron powders such as iron
powders comprising particles, a surface of each of which is at
least partially covered with an oxygen-containing film, and iron
alloy powders comprising particles, a surface of each of which is
at least partially covered with an oxygen-containing film, are
preferable. Incidentally, the "iron oxide film" as referred to
herein is a film made of oxygen-containing iron such as iron oxide,
hydroxide or oxyhydroxide. Furthermore, the "active iron powder" as
referred to herein is a powder in which an iron oxide film is
formed at least locally on the surface of an iron powder, from
which an oxidation reaction promoting effect is obtained by a local
cell as formed between an iron matrix and an iron oxide film or a
pit inside and outside the iron oxide film.
[0100] The iron powder is not limited, and examples thereof include
cast iron powders, atomized iron powders, electrolyzed iron
powders, reduced iron powders, sponge iron powders, and iron alloy
powders thereof. In addition, the iron powder may contain carbon or
oxygen, and an iron powder containing 50% or more of iron and other
metals may be employed. The kind of the metal which is contained as
an alloy, etc. is not particularly limited so far as the iron
component works as a component of the heat generating composition.
Examples of such a metal include metals such as aluminum,
manganese, copper, nickel, silicon, cobalt, palladium, and
molybdenum, and semiconductors. The metal of the invention includes
a semiconductor. Such a metal or alloy may be contained only in the
surface or the interior, or may be contained in both the surface
and the interior.
[0101] In the iron powder of the invention, the content of the
metal other than iron is usually from 0.01 to 50% by weight, and
preferably from 0.1 to 10% by weight based on the whole of the iron
powder.
[0102] Examples of the iron powder having an oxygen-containing film
on at least a part of the surface of the iron include:
[0103] (A) an active iron powder in which the surface of an iron
component is at least partially oxidized, which is obtained by
contact treating the essential components of the heat generating
composition or the essential components to which acidic substances
or other necessary components are added with an oxidizing gas,
thereby partially oxidizing the iron component;
[0104] (B) an active iron powder in which the content of wustite is
from 2 to 50% by weight in terms of an X-ray peak intensity ratio
to iron;
[0105] (C) an iron powder having an iron oxide film having a
thickness of 3 nm or more on the surface thereof; and
[0106] (D) a mixture of an active iron powder and an iron powder
other than an active iron powder.
[0107] With respect to (A), although the mechanism is not
elucidated in detail, it is assumed that upon contact between the
oxidizing gas and the components, not only an iron oxide film,
namely, an oxygen-containing film is formed on the surface of the
iron powder due to the oxidation of the components, especially the
oxidation of the iron powder, but also the surface of active carbon
is oxidized and/or the oxidized iron component is adhered, whereby
hydrophilicity is imparted or improved, and coupling between the
components or structurization takes place through the mediation of
water.
[0108] That is, it is assumed that some kind of a change in the
function occurs such that an iron oxide film is formed on the
surface of the iron powder, the shape of the iron powder particle
becomes irregular, a strain is generated due to the oxidation, or a
water-containing pit is formed, whereby the iron powder is
activated and exothermic rising properties are improved.
[0109] Furthermore, the case where magnetite (Fe.sub.3O.sub.4) is
present in the iron oxide film is preferable because the
conductivity is excellent, and the case where hematite
(Fe.sub.2O.sub.3) is present in the iron oxide film is also
preferable because the iron oxide film becomes porous. Moreover, it
is assumed that the carbon component is oxidized on the surface
thereof and becomes a carbon component which is rich in oxides on
the surface thereof, whereby the hydrophilicity increases and the
activity increases.
[0110] The thickness of the iron oxide film which is an
oxygen-containing film covering the surface of the iron powder, as
measured by the Auger electron spectroscopy, is usually 3 nm or
more, preferably from 3 nm to 100 .mu.m, more preferably from 30 nm
to 100 .mu.m, further preferably from 30 nm to 50 .mu.m, still
further preferably from 30 nm to 1 .mu.m, even further preferably
from 30 nm to 500 nm, and even still further preferably from 50 nm
to 300 nm.
[0111] When the thickness of the oxygen-containing film of iron is
3 nm or more, the thickness of the oxygen-containing film of iron
is able to exhibit a promoting effect of the oxidation reaction,
and upon contact with an oxidizing gas such as air, is able to
immediately initiate the oxidation reaction. When the thickness of
the oxygen-containing film of iron is 100 .mu.m or more, though the
heat generation time may possibly be shortened, such is applicable
depending upon the utility.
[0112] Furthermore, according to the active iron powder, by using a
reaction mixture containing, as essential components, an iron
powder, a reaction accelerator and water and having a water content
of from 0.5 to 20% by weight and a water mobility value showing a
surplus water content of less than 0.01, the reaction rate at the
time of the contact treatment with an oxidizing gas can be raised,
thereby achieving a time required for regulating a temperature rise
of the reaction mixture at 1.degree. C. or more within 10 minutes.
By shortening a time required for arrival at a prescribed
temperature or higher, proper activation can be achieved, and
unnecessary oxidation on the iron powder can be prevented.
[0113] Furthermore, the heat generating composition prepared by
adding a carbon component, etc. to a heat generating mixture as
produced by contact treating the reaction mixture with an oxidizing
gas or adjusting the water content so as to have a water mobility
value of from 0.01 to 50 is properly tacky, has excellent
moldability and is able to be applied with a molding method such as
a force-through die molding method and a cast molding method,
whereby heat generating bodies of various shapes can be produced.
In particular, a heat generating composition having a water
mobility value of from 0.01 to 20 is excellent because it initiates
an exothermic reaction immediately after contacting with air, has
excellent exothermic rising properties and has excellent
moldability.
[0114] The contact treatment method of the reaction mixture with an
oxidizing gas is not particularly limited so far as it is able to
contact treat a reaction mixture containing, as essential
components, an iron powder, a reaction accelerator and water and
having a water content of from 0.5 to 20% by weight and a water
mobility value of less than 0.01 with an oxidizing gas and regulate
a temperature rise of the reaction mixture at 1.degree. C. or
more.
[0115] Specific examples thereof include:
[0116] (1) a process for producing a heat generating mixture
containing an iron powder having an iron oxide film on the surface
thereof by subjecting a reaction mixture of an iron powder, a
reaction accelerator and water in an oxidizing gas atmosphere to a
self-exothermic reaction, thereby partially oxidizing the iron
powder;
[0117] (2) a process for producing a heat generating mixture by
subjecting a reaction mixture of an iron powder, a reaction
accelerator, an acidic substance and water in an oxidizing gas
atmosphere to a self-exothermic reaction;
[0118] (3) a process for producing a heat generating mixture by
subjecting a reaction mixture of an iron powder, a reaction
accelerator, a carbon component and water in an oxidizing gas
atmosphere to a self-exothermic reaction;
[0119] (4) a process for producing a heat generating mixture by
subjecting a reaction mixture of an iron powder, a reaction
accelerator, an acidic substance, a carbon component and water in
an oxidizing gas atmosphere to a self-exothermic reaction;
[0120] (5) a process for producing a heat generating mixture
containing a partially oxidized iron powder by carrying out the
method as set forth above in any one of (1) to (4), wherein the
reaction mixture or heat generating mixture as set forth above in
any one of (1) to (4) contains a component other than the foregoing
components;
[0121] (6) a process for producing a heat generating mixture by
carrying out the method as set forth above in any one of (1) to (5)
under circumstances heated so as to have temperature of at least
10.degree. C. higher than the circumferential temperature;
[0122] (7) a process for producing a heat generating mixture by
carrying out the method as set forth above in any one of (1) to (6)
by blowing an oxidizing gas;
[0123] (8) a process for producing a heat generating mixture by
carrying out the method as set forth above in (7) by blowing the
oxidizing gas heated so as to have a temperature of at least
10.degree. C. higher than the circumferential temperature;
[0124] (9) a process for producing a heat generating composition by
carrying out the method as set forth above in any one of (1) to (8)
by contact treating with an oxidizing gas until the temperature
exceeds a maximum temperature which is a maximum point of
temperature rise by the exothermic reaction;
[0125] (10) a process for producing a heat generating mixture by
carrying out the method as set forth above in any one of (1) to (8)
by contact treating with an oxidizing gas until the temperature
exceeds a maximum temperature by the exothermic reaction and drops
by at least 10 to 20.degree. C. from the maximum temperature;
[0126] (11) a process for producing a heat generating composition
by carrying out the method as set forth above in any one of (1) to
(8) by contact treating with an oxidizing gas until the temperature
exceeds a maximum temperature which is a maximum point of
temperature rise by the exothermic reaction and after intercepting
the oxidizing gas, holding it until the temperature of at least the
reaction mixture drops by at least 10 to 20.degree. C. from the
maximum temperature; and
[0127] (12) a process for producing a heat generating mixture by
heating the reaction mixture or heat generating mixture as set
forth above in any one of (1) to (5) under oxidizing gas
circumstances while regulating a temperature rise at 1.degree. C.
or more.
[0128] In addition, a heat generating mixture as prepared by adding
other components to the heat generating mixture and further
treating with an oxidizing gas may be employed.
[0129] Incidentally, the circumstances of the reaction mixture at
the time of contact treatment with an oxidizing gas are not limited
so far as the reaction mixture is brought into contact with an
oxidizing gas under circumstances of 0.degree. C. or higher and a
temperature rise of the reaction mixture is regulated at 1.degree.
C. or more within 10 minutes. In the case where the contact
treatment is carried out in an open system, the circumstances may
be either the state that the reaction mixture is present in a
lid-free vessel or the state that an oxidizing gas such as air
comes into a vessel through an air-permeable sheet-like material
such as non-woven fabrics.
[0130] Furthermore, the contact treatment with an oxidizing gas may
be carried out with or without stirring in a fluidized or
non-fluidized state and may be carried out in a batch or continuous
system.
[0131] Examples of the final heat generating composition
include:
[0132] 1) a heat generating composition containing, as a heat
generating composition raw material, a heat generating mixture
produced in the process as set forth above in any one of (1) to
(12);
[0133] 2) a heat generating composition obtained by adding other
components to the heat generating composition as set forth above in
1); and
[0134] 3) a heat generating composition obtained by adjusting the
water content of the heat generating composition as set forth above
in 1) or 2).
[0135] The order of the timing of adding other components than the
essential components and the timing of adjusting the water content
is not limited.
[0136] Here, the water content in the reaction mixture and also the
heat generating mixture prior to the treatment with an oxidizing
gas is usually from 0.5 to 20% by weight, preferably from 1 to 15%
by weight, more preferably from 2 to 10% by weight, further
preferably from 3 to 10% by weight, and still further preferably
from 6 to 10% by weight.
[0137] The temperature of the reaction mixture after the contact
with an oxidizing gas is not limited so far as the temperature rise
is regulated at 1.degree. C. or more. The temperature of the
reaction mixture after the contact with an oxidizing gas is
preferably from 1 to 80.degree. C., more preferably from 1 to
70.degree. C., further preferably from 1 to 60.degree. C., and
still further preferably from 1 to 40.degree. C. The
circumferential temperature at the time of contact between the
reaction mixture and the oxidizing gas is not limited so far as the
temperature of the reaction mixture is raised to a prescribed
temperature or higher. The circumferential temperature at the time
of contact between the reaction mixture and the oxidizing gas is
preferably 0.degree. C. or higher, more preferably from 0 to
250.degree. C., further preferably from 10 to 200.degree. C., still
further preferably from 20 to 150.degree. C., even further
preferably from 25 to 100.degree. C., and even still further
preferably from 25 to 50.degree. C.
[0138] The time of contact between the reaction mixture and the
oxidizing gas is not limited so far as the time required for
regulating a temperature rise at 1.degree. C. or more is within 10
minutes. The time of contact between the reaction mixture and the
oxidizing gas is preferably from one second to 10 minutes, more
preferably from one second to 7 minutes, further preferably from
one second to 5 minutes, still further preferably from 2 seconds to
5 minutes, even further preferably from 2 seconds to 3 minutes, and
even still further preferably from 2 seconds to one minute.
[0139] The temperature of the oxidizing gas is not limited so far
as the foregoing circumferential temperature is kept.
[0140] As the "oxidizing gas" as referred to herein, any gas can be
used as the oxidizing gas so far as it is oxidizing. Examples
thereof include an oxygen gas, air, and mixed gases of an inert gas
(for example, a nitrogen gas, an argon gas, and a helium gas) and
an oxygen gas. Although the mixed gas is not limited so far as it
contains oxygen, mixed gases containing 10% or more of an oxygen
gas are preferable, and of these, air is especially preferable. If
desired, a catalyst such as platinum, palladium, iridium, and
compounds thereof can also be used.
[0141] The oxidation reaction can be carried out under stirring in
an oxidizing gas atmosphere optionally under a pressure and/or upon
irradiation of ultrasonic waves.
[0142] The optimal condition of the oxidation reaction may be
properly experimentally determined.
[0143] An amount of the oxidizing gas to be used is not limited but
may be adjusted depending upon the kind of the oxidizing gas, the
kind and particle size of the iron powder, the water content, the
treatment temperature, the treatment method, and the like.
[0144] In the case of an open system, there is no limitation so far
as a necessary amount of oxygen can be taken in. In order to
prevent fly of the reaction mixture or contamination of dusts,
etc., the system may be surrounded by an air-permeable raw material
such as non-woven fabrics and woven fabrics. So far as the system
is in an air-permeable state, it is to be noted that the system is
an open system.
[0145] In the case where air is used in the system of blowing an
oxidizing gas, for example, the amount of air is preferably from
0.01 to 1,000 L/min, more preferably from 0.01 to 100 L/min, and
further preferably from 0.1 to 50 L/min per 200 g of the iron
powder under one atmosphere. In the case of other oxidizing gas,
the amount of the oxidizing gas may be converted on the basis of
the case of air.
[0146] If desired, a peroxide may be added. Examples of the
peroxide include hydrogen peroxide and ozone.
[0147] Here, so far as the iron powder is partially oxidized, the
state of the reaction mixture or heat generating mixture at the
time of the contact treatment with an oxidizing gas may be any of a
standing state, a transfer state, or a fluidizing state by
stirring, etc. and may be properly selected. Furthermore, the
circumstances at the time of mixing the respective components of
the reaction mixture, the heat generating mixture or the heat
generating composition and at the time of the contact treatment
with a mixed oxidizing gas at the time of adjusting the water
content are not limited, and examples thereof include those in an
oxidizing gas atmosphere and those in blowing of an oxidizing
gas.
[0148] A method for measuring a temperature rise of the heat
generating composition is as follows.
[0149] 1) A heat generating composition is allowed to stand in a
state that it is sealed in an air-impermeable outer bag for one
hour under a condition that the circumferential temperature is
20.+-.1.degree. C.
[0150] 2) A magnet is provided in the vicinity of a central part of
the back side of a polyvinyl chloride-made supporting plate (3 mm
in thickness.times.600 mm in length.times.600 mm in width) of a
footed supporting table so as to cover a cavity shape of a molding
die.
[0151] 3) A temperature sensor is placed on the central part of the
supporting plate.
[0152] 4) A polyethylene film (25 .mu.m in thickness.times.250 mm
in length.times.200 mm in width) as provided with an adhesive layer
having a thickness of about 80 .mu.m is stuck onto the supporting
plate via a sticky layer such that the center of the polyethylene
film is positioned at the sensor.
[0153] 5) The heat generating composition is taken out from the
outer bag.
[0154] 6) A template (250 mm in length.times.200 mm in width)
having a cavity (80 mm in length.times.50 mm in width.times.3 mm in
height) is placed above the central part of the polyethylene film;
a sample is placed in the vicinity of the cavity; a force-in die
plate is moved along the template; the sample is charged into the
cavity while stuffing; and the sample is leveled while stuffing
along the template plane (force-in die molding), thereby filling
the sample in the die. Next, the magnet beneath the supporting
plate is removed, and the temperature measurement is started.
[0155] With respect to the measurement of the exothermic
temperature, the temperature is measured for 10 minutes at a
measurement timing of 2 seconds using a data collector, and
exothermic rising properties are judged in terms of the temperature
after elapsing 3 minutes.
[0156] The heat generation test of the heat generating body follows
the JIS temperature characteristic test.
[0157] In the iron powder or active iron powder in the oxidizing
gas-treated heat generating composition, at least a part of the
surface thereof is covered by an oxygen-containing film of iron.
The degree of covering on the surface of the oxygen-containing film
of iron is not limited so far as at least a part of the surface
thereof is covered, and the surface may be entirely covered. In the
case of the heat generating composition of the invention, since an
ion of the reaction accelerator such as a chlorine ion is contained
in the heat generating composition, there is no corrosion effect of
the oxide film due to anti-corrosion effect by the ion of the
reaction accelerator such as a chlorine ion. Thus, the oxidation
reaction which is a sort of corrosion is not hindered. In
particular, in the case where an oxygen-containing film of iron is
prepared while the ion of the reaction accelerator such as a
chlorine ion exists together, the subject effect is large. In the
case where a metal other than iron is present on the surface, it is
only required that at least other part of the metal portion other
than iron is covered by the oxygen-containing film of iron.
[0158] In the iron powder of the invention, not only a region where
(1) entire (uniform) corrosion, (2) pitting or crevice corrosion,
(3) stress corrosion cracking, or the like is generated, but also
irregularities or crevices are formed. For that reason, it is
assumed that the iron powder of the invention has hydrophilicity
and oxidation catalytic properties (FeO, etc.) in its own portion.
In producing the heat generating composition, it is important that
the iron powder has an oxygen-containing film in its own portion
without relying upon mixing. In particular, in the iron component
as prepared by contact treating the iron component and the reaction
accelerator and water as essential components with an oxidizing
gas, it is thought that a reaction active part composed mainly of
an oxide, a hydroxide, a chlorine ion, a hydrogen ion, etc. is
formed, whereby exothermic reactivity and hydrophilicity are
improved and exothermic rising properties and moldability are
remarkably improved.
[0159] With respect to (B), the amount of FeO (wustite) which is
contained in the iron component containing a prescribed amount of
wustite is usually from 2 to 50% by weight, preferably from 2 to
40% by weight, more preferably from 2 to 30% by weight, further
preferably from 5 to 30% by weight, and still further preferably
from 6 to 30% by weight in terms of an X-ray peak intensity ratio
of iron. When the amount of FeO (wustite) exceeds 50% by weight,
though the exothermic rising properties are good, the duration of
heat generation becomes short. On the other hand, when it is less
than 2% by weight, the exothermic rising properties become
dull.
[0160] The thickness of the oxygen-containing film of a prescribed
amount or the oxygen-containing film of iron powder containing
wustite and the amount of wustite are applied to the heat
generating composition or the heat generating composition molded
body at the time of lamination.
[0161] An iron powder containing a carbon component and/or covered
by a carbon component is also preferable. Although a proportion of
the carbon component is not limited so far as a ratio of the iron
component to the carbon component is 50% by weight or more, an iron
powder in which the surface thereof is partially covered by from
0.3 to 3.0% by weight of a conductive carbonaceous substance is
useful. Examples of the conductive carbonaceous substance include
carbon black, active carbon, carbon nanotubes, carbon nanohorns,
and flullerenes. Ones which have become conductive by doping are
also employable. Examples of the iron powder include reduced iron
powders, atomized iron powders, and sponge iron powders. In
particular, the case where the conductive carbonaceous substance is
active carbon and the iron powder is a reduced iron powder is
useful as a heat generating body.
[0162] Furthermore, in order to efficiently carry out covering by a
conductive carbonaceous substance, an oil such as a spindle oil may
be added in an amount of from 0.01 to 0.05% by weight to such an
extent that the fluidity of the iron powder is not hindered.
[0163] In the case of measuring the water mobility value of the
heat generating composition in the heat generating body and the
thickness and amount of wustite of the iron oxide film of iron
powder in the mixture or the heat generating composition in the
heat generating body, the heat generating composition or mixture
may be measured according to the following items.
1) Water Mobility Value:
[0164] The heat generating composition is taken out from the heat
generating body and measured according to the foregoing method of
measuring a water mobility value.
2) Thickness and Amount of Wustite of Iron Oxide Film of Iron
Powder:
[0165] A measuring sample as prepared by dispersing the heat
generating composition, the heat generating composition molded
body, the heat generating composition compression molded body or
the mixture in nitrogen-purged ion-exchanged water in a nitrogen
atmosphere, separating the iron powder using a magnet and drying
the iron powder in a nitrogen atmosphere is used.
[0166] The heat generating composition of the invention contains,
as essential components, an iron powder, a carbon component, a
reaction accelerator and water, and its production process is one
which can be put into practical use on an industrial scale. A
reaction mixture containing, as essential components, an iron
powder, a reaction accelerator and water and having a water content
of from 1 to 20% by weight and a water mobility value showing a
surplus water content of less than 0.01 is brought into contact
with an oxidizing gas under circumstances at 0.degree. C. or
higher, a temperature rise of the reaction mixture is regulated at
1.degree. C. or more within 10 minutes to produce a heat generating
mixture, and the subject heat generating mixture is used as a raw
material to form a heat generating composition. Alternatively, a
heat generating composition may be formed by subsequently further
adjusting the water content, or by further adding a carbon
component, etc. and adjusting the water content.
[0167] In the invention, it has become possible to realize the
contact treatment with an oxidizing gas within a short period of
time by regulating the water content of the reaction mixture at a
fixed amount or less, especially regulating the surplus water
content of the reaction mixture at a fixed amount or less and
carrying out an oxidizing contact treatment. By specifying the
surplus water content and performing the treatment within a short
period of time, adverse influences such as poor initial exothermic
rising of the heat generating composition and shortening of the
heat generation-retaining time can be avoided. Thus, it has become
possible to establish an industrial mass-production process.
Furthermore, although stirring or the like may not be achieved
during the contact treatment with an oxidizing gas, when stirring
or the like is achieved, the contact treatment with an oxidizing
gas can be surely carried out.
[0168] Here, so far as the iron powder is partially oxidized, the
state of the reaction mixture or heat generating mixture at the
time of the contact treatment with an oxidizing gas may be any of a
standing state, a transfer state, or a fluidizing state by
stirring, etc. and may be properly selected. Furthermore, the
circumstances at the time of mixing the respective components of
the reaction mixture, the heat generating mixture or the heat
generating composition and at the time of mixing at the time of
adjusting the water content are not limited, and examples thereof
include those in an oxidizing gas atmosphere and those in blowing
of an oxidizing gas.
[0169] The "adjustment of the water content" as referred to herein
means that after contact treating the heat generating mixture with
an oxidizing gas, water or an aqueous solution of a reaction
accelerator is added. Although the amount of addition of water or
an aqueous solution of a reaction accelerator is not limited,
examples thereof include the addition of a weight corresponding to
a reduced weight by the contact treatment and the addition of a
weight such that a desired water mobility value is obtained.
Whether or nor the adjustment of the water content is introduced
may be properly determined depending upon the utility.
[0170] The heat generating composition of the invention contains,
as essential components, an iron powder, a carbon component, a
reaction accelerator and water and is started from a mixture
obtained by contact treating a reaction mixture containing, as
essential components, an iron powder, a reaction accelerator and
water with an oxidizing gas. The heat generating composition of the
invention is usually one obtained by adjusting the water content of
a heat generating mixture and is a heat generating composition
which is satisfactory in the exothermic rising, has a suitable
amount of surplus water and has excellent moldability. Furthermore,
it is possible to produce a heat generating body which can become
promptly warm at the time of use.
[0171] Accordingly, at least the iron powder further including the
carbon component has a history of oxidation by the contact
treatment with an oxidizing gas, and it is thought that this is
deeply related to excellent exothermic rising properties,
exothermic endurance and excellent moldability.
[0172] When the iron powder which is contact treated with an
oxidizing gas according to the invention is used, the amount of
addition of the carbon component (for example, active carbon) in
the heat generating composition can be reduced by, for example, 20%
or more. By reducing the amount of addition of the carbon
component, the costs are lowered.
[0173] According to the production process of the heat generating
mixture of the invention, it is possible to obtain a heat
generating composition having excellent exothermic rising
properties, excellent hydrophilicity, and excellent moldability. In
particular, a heat generating composition having remarkably
excellent moldability and exothermic characteristics together can
be obtained while specifying the water availability value at from
0.01 to 50, in particular from 0.01 to 20.
[0174] The heat generating composition as produced by the
production process of the invention is remarkably improved with
respect to exothermic rising properties. Thus, the amount of
addition of the carbon component (such as active carbon) in the
heat generating composition can be reduced by, for example, 20% or
more so that it can contribute to a reduction in costs.
[0175] Furthermore, since the hydrophilicity is remarkably
improved, the moldability with a mold is remarkably improved. Thus,
since after molding, collapsed pieces of the heat generating
composition are not scattered on the surroundings of the heat
generating composition molded body, sealing can be appropriately
achieved so that a heat generating body free from sealing cut can
be produced. In this way, heat generating composition molded bodies
of various shapes can be produced, and heat generating bodies of
various shapes are formed.
[0176] Furthermore, in view of improving the exothermic rising
properties of the heat generating composition, the following are
preferable.
[0177] 1) A heat generating composition obtained by a contact
treatment (self heat generation) of a mixture of the essential
components of the heat generating composition, or a mixture of the
foregoing mixture and an acidic substance or other necessary
components with an oxidizing gas, a heat generating composition
obtained by additionally adjusting the water content of the
foregoing heat generating composition, or a heat generating
composition obtained by adding and mixing other components in the
foregoing heat generating composition.
[0178] 2) Any one of the following active iron powders having an
oxygen-containing film (for example, oxides) on at least a part of
the surface thereof is used as the iron powder: (a) an iron powder
having an oxygen-containing film of iron having a thickness, as
measured by the Auger electron spectroscopy, of 3 nm or more on the
surface thereof and (b) an iron powder having a content of wustite
of from 2 to 50% by weight in terms of an X-ray peak intensity
ratio to iron.
[0179] 3) A mixture of an active iron powder having an
oxygen-containing film (for example, oxides) on at least a part of
the surface thereof and an iron powder not having an
oxygen-containing film is used as the iron powder. In this case, a
mixture containing 60% by weight or more of an active iron powder
and less than 40% by weight of an iron powder other than the active
iron is preferable.
[0180] In the case of storing the heat generating composition which
is treated with an oxidizing gas or the heat generating composition
containing an active iron powder, or a material utilizing the same
over a long period of time, it is preferred to combine a hydrogen
formation inhibitor therewith. This is because in this way, a heat
generating body having excellent exothermic characteristics, which
is inhibited in the formation of hydrogen, is free from swelling of
the outer bag at the time of storage, etc. and has satisfactory
exothermic rising properties, is obtained.
[0181] In addition, if desired, at least one member selected from
additional components consisting of a water retaining agent, a
water absorptive polymer, a pH adjusting agent, a hydrogen
formation inhibitor, an aggregate, a fibrous material, a functional
substance, a surfactant, an organosilicon compound, a pyroelectric
substance, a moisturizer, a fertilizer component, a hydrophobic
polymer compound, a heat generating aid, a metal other than iron, a
metal oxide other than iron oxide, an acidic substance, and a
mixture thereof may be further added to the heat generating
composition.
[0182] Furthermore, in the heat generating composition of the
invention or the like, although there is no particular limitation
for the blending ratio thereof, it is preferred to select the
blending ratio such that the amount of the reaction accelerator is
from 1.0 to 50 parts by weight, the amount of water is from 1.0 to
60 parts by weight, the amount of the carbon component is from 1.0
to 50 parts by weight, the amount of the water retaining agent is
from 0.01 to 10 parts by weight, the amount of the water absorptive
polymer is from 0.01 to 20 parts by weight, the amount of the pH
adjusting agent is from 0.01 to 5 parts by weight, and the amount
of the hydrogen formation inhibitor is from 0.01 to 12 parts by
weight, respectively based on 100 parts by weight of the iron
powder; and that the heat generating composition has a water
mobility value of from 0.01 to 20. In addition, the following
components may be added in blending ratios as described below to
the iron powder to the heat generating composition. That is, the
amount of the metal other than iron is from 1.0 to 50 parts by
weight, the amount of the metal oxide other than iron oxide is from
1.0 to 50 parts by weight, the amount of the surfactant is from
0.01 to 5 parts by weight, the amount of each of the hydrophobic
polymer compound, the aggregate, the fibrous material, the
functional substance, the organosilicon compound and the
pyroelectric substance is from 0.01 to 10 parts by weight, the
amount of each of the moisturizer, the fertilizer component and the
heat generating aid is from 0.01 to 10 parts by weight, and the
amount of the acidic substance is from 0.01 to 1 part by weight,
respectively. Incidentally, a magnetic body may further be blended,
and its blending ratio may be properly determined depending upon
the desire.
[0183] Incidentally, these blending ratios can also be applied in a
reaction mixture and a heat generating mixture. Furthermore, a
water mobility value of the reaction mixture is usually less than
0.01.
[0184] As the water, one from a proper source may be employed. Its
purity and kind and the like are not particularly limited.
[0185] In the case of the heat generating composition, the content
of water is preferably from 1 to 70% by weight, more preferably
from 1 to 60% by weight, further preferably from 7 to 60% by
weight, still further preferably from 10 to 50% by weight, and even
further preferably from 20 to 50% by weight of the heat generating
composition.
[0186] Furthermore, in the case of the reaction mixture or heat
generating mixture prior to the contact treatment with an oxidizing
gas, the content of water is preferably from 0.5 to 20% by weight,
more preferably from 3 to 20% by weight, further preferably from 4
to 15% by weight, and still further preferably from 7 to 15% by
weight of the reaction mixture or heat generating mixture.
[0187] The carbon component is not particularly limited so far as
it contains carbon as a component. Examples thereof include carbon
black, graphite, active carbon, carbon nanotubes, carbon nanohorns,
and flullerenes. Carbon which has become conductive by doping or
the like is also employable. There are enumerated active carbons as
prepared from coconut shell, wood, charcoal, coal, bone carbon,
etc. and carbons as prepared from other raw materials such as
animal products, natural gases, fats, oils, and resins. In
particular, active carbons having an adsorption retaining ability
are preferable.
[0188] Furthermore, it is not always required that the carbon
component is present alone. In the case where an iron powder
containing the carbon component and/or covered by the carbon
component is used in the heat generating composition, it is to be
noted that the heat generating composition contains the carbon
component even though the carbon component is not present
alone.
[0189] The reaction accelerator is not particularly limited so far
as it is able to promote the reaction of the heat generating
substance. Examples thereof include metal halides, nitrates,
acetates, carbonates, and metal sulfates. Examples of metal halides
include sodium chloride, potassium chloride, magnetic chloride,
calcium chloride, ferrous chloride, ferric chloride, sodium
bromide, potassium bromide, ferrous bromide, ferric bromide, sodium
iodide, and potassium iodide. Examples of nitrates include sodium
nitrate and potassium nitrate. Examples of acetates include sodium
acetate. Examples of carbonates include ferrous carbonate. Examples
of metal sulfates include potassium sulfate, sodium sulfate, and
ferrous sulfate.
[0190] The water retaining agent is not limited so far as it is
able to retain water. Examples thereof include porous materials
derived from plants having high capillary function and
hydrophilicity such as wood meal, pulp powder, active carbon, saw
dust, cotton cloth having a number of cotton fluffs, short fiber of
cotton, paper dust, and vegetable materials, water-containing
magnesium silicate based clay minerals such as active clay and
zeolite, pearlite, vermiculite, silica based porous substances,
coralline stone, and volcanic ash based substances (for example,
terra balloon, shirasu balloon, and taisetsu balloon). In order to
increase a water retaining ability and enhance a shape holding
ability of such a water retaining agent, the water retaining agent
may be subjected to a processing treatment such as baking and/or
pulverization. The water absorptive polymer is not particularly
limited so far as it is a resin having a crosslinking structure and
having a water absorption magnification of ion-exchanged water of 3
times or more of the dead weight. Furthermore, a water absorptive
polymer the surface of which is crosslinked may be employed.
Conventionally known water absorptive polymers and commercial
products may also be employed.
[0191] Examples of the water absorptive polymer include
poly(meth)acrylic acid crosslinked materials, poly(meth)-acrylic
acid salt crosslinked materials, sulfonic group-containing
poly(meth)acrylic ester crosslinked materials, polyoxyalkylene
group-containing poly(meth)acrylic ester crosslinked materials,
poly(meth)acrylamide crosslinked materials, crosslinked materials
of a copolymer of a (meth)acrylic acid salt and a (meth)acrylamide,
crosslinked materials of a copolymer of a hydroxyalkyl
(meth)acrylate and a (meth) acrylic acid salt, polydioxolane
crosslinked materials, crosslinked polyethylene oxide, crosslinked
polyvinylpyrrolidone, sulfonated polystyrene crosslinked materials,
crosslinked polyvinylpyridine, saponification products of a
starch-poly (meth) acrylonitrile graft copolymer,
starch-poly(meth)acrylic acid (salt) graft crosslinked copolymers,
reaction products of polyvinyl alcohol and maleic anhydride (salt),
crosslinked polyvinyl alcohol sulfonic acid salts, polyvinyl
alcohol-acrylic acid graft copolymers, and polyisobutylene maleic
acid (salt) crosslinked polymers. These water absorptive polymers
may be used alone or in combination with two or more kinds
thereof.
[0192] Of these water absorptive polymers, water absorptive
polymers having biodegradation properties are not limited so far as
they are a biodegradable water absorptive polymer. Examples thereof
include polyethylene oxide crosslinked materials, polyvinyl alcohol
crosslinked materials, carboxymethyl cellulose crosslinked
materials, alginic acid crosslinked materials, starch crosslinked
materials, polyamino acid crosslinked materials, and polylactic
acid crosslinked materials.
[0193] The pH adjusting agent is not limited so far it is able to
adjust the pH. Examples thereof include alkali metal weak acid
salts and hydroxides and alkaline earth metal weak acid salts and
hydroxides such as Na.sub.2CO.sub.3, NaHCO.sub.3, Na.sub.3PO.sub.4,
Na.sub.2HPO.sub.4, Na.sub.5P.sub.3O.sub.10, NaOH, KOH,
Ca(OH).sub.2, Mg(OH).sub.2, and Ca.sub.3(PO.sub.4).sub.2.
[0194] The hydrogen formation inhibitor is not limited so far as it
is able to inhibit the formation of hydrogen. Examples thereof
include one member or two or more members selected from the group
consisting of sulfur compounds, oxidizing agents, alkaline
substances, sulfur, antimony, selenium, phosphorus, and tellurium.
Incidentally, examples of sulfur compounds include compounds with
an alkali metal or an alkaline earth metal, metal sulfides such as
calcium sulfide, metal sulfites such as sodium sulfite, and metal
thiosulfates such as sodium thiosulfate.
[0195] Examples of the oxidizing agent include nitrates, oxides,
peroxides, halogenated oxygen acid salts, permanganates, and
chromates.
[0196] The aggregate is not limited so far as it is useful as a
filler and/or is useful for making the heat generating composition
porous. Examples thereof include fossilized coral (for example,
coral fossil and weathered coral fossil), bamboo charcoal, bincho
charcoal, silica-alumina powders, silica-magnesia powders, kaolin,
crystalline cellulose, colloidal silica, pumice, silica gel, silica
powders, mica powders, clays, talc, synthetic resin powders or
pellets, foamed synthetic resins such as foamed polyesters or
polyurethanes, diatomaceous earth, alumina, and cellulose powder.
Incidentally, it is to be noted that kaolin and crystalline
cellulose are not contained in the heat generating composition of
the invention.
[0197] The fibrous material is an inorganic fibrous material and/or
an organic fibrous material. Examples thereof include rock wool,
glass fibers, carbon fibers, metal fibers, pulps, papers, non-woven
fabrics, woven fabrics, natural fibers such as cotton and hemp,
regenerated fibers such as rayon, semi-synthetic fibers such as
acetates, synthetic fibers, and pulverized products thereof.
[0198] The functional substance is not limited so far as it is a
substance having any function. Examples thereof include at least
one member selected from minus ion emitting substances and far
infrared ray radiating substances. The minus ion emitting substance
is not limited so far as it emits a minus ion as a result either
directly or indirectly, and examples thereof include ferroelectric
substances such as tourmaline, fossilized coral, granite, and
calcium strontium propionate, and ores containing a radioactive
substance such as radium and radon. The far infrared ray radiating
substance is not limited so far as it radiates far infrared rays.
Examples thereof include ceramics, alumina, zeolite, zirconium, and
silica.
[0199] The surfactant includes anionic surfactants, cationic
surfactants, nonionic surfactants, and ampholytic surfactants.
Especially, nonionic surfactants are preferable, and examples
thereof include polyoxyethylene alkyl ethers, alkylphenol-ethylene
oxide adducts, and higher alcohol phosphoric acid esters.
[0200] The organosilicon compound is not limited so far as it is a
compound having at least an Si--O--R bond and/or an Si--N--R bond
and/or an Si--R bond. The organosilicon compound is in the form of
a monomer, a lowly condensed product, a polymer, etc. Examples
thereof include organosilane compounds such as
methyltriethoxysilane; and dimethylsilicone oil,
polyorganosiloxane, or silicone resin compositions containing the
same.
[0201] The pyroelectric substance is not limited so far as it has
pyroelectricity. Examples thereof include tourmaline, hemimorphic
ores, and pyroelectric ores. Tourmaline or achroite which is a kind
of tourmaline is especially preferable. Examples of the tourmaline
included ravite, schorl, and elbaite.
[0202] The moisturizer is not limited so far as it is able to hold
moisture. Examples thereof include hyaluronic acid, collagen,
glycerin, and urea.
[0203] The fertilizer component is not limited so far as it is a
component containing at least one of three elements of nitrogen,
phosphorus and potassium. Examples thereof include a bone powder,
urea, ammonium sulfate, calcium perphosphate, potassium chloride,
and calcium sulfate.
[0204] The hydrophobic polymer compound is not limited so far as it
is a polymer compound having a contact angle with water of
40.degree. or more, preferably 50.degree. or more, and more
preferably 60.degree. or more in order to improve the draining in
the composition. The shape of the hydrophobic polymer compound is
not limited, and examples thereof include powdery, particulate,
granular, and tablet shapes. Examples of the hydrophobic polymer
compound include polyolefins such as polyethylene and
polypropylene, polyesters, and polyamides.
[0205] Examples of the heat generating aid include metal powders,
metal salts, and metal oxides such as Cu, Mn, CuCl.sub.2,
FeCl.sub.2, manganese dioxide, cupric oxide, triiron tetroxide, and
mixtures thereof.
[0206] As the metal oxide other than iron oxide, any material can
be employed so far as it does not hinder the oxidation of iron by
an oxidizing gas, and examples thereof include manganese dioxide
and cupric oxide.
[0207] The acidic substance may be any of an inorganic acid, an
organic acid, or an acidic salt. Examples thereof include
hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic
acid, citric acid, malic acid, maleic acid, chloroacetic acid, iron
chloride, iron sulfate, iron oxalate, iron citrate, aluminum
chloride, ammonium chloride, and hypochlorous acid.
[0208] The process for producing a heat generating body according
to the invention is a process for producing a heat generating body
which is characterized by laminating a heat generating composition
molded body resulting from molding a heat generating composition
containing, as essential components, an iron powder, a carbon
component, a reaction accelerator and water on a substrate,
providing thereon an adhesive as an air-permeable sticky layer by a
melt blow system or the like, and further covering a covering
material on the substrate and the heat generating composition
molded body; or covering a covering material provided with an
adhesive as an air-permeable sticky layer by a melt blow system or
the like, carrying out contact bonding by temporary adhesion rolls,
thereby temporarily adhering the substrate and the heat generating
composition molded body to the covering material, and heat sealing
the substrate in the periphery of the heat generating composition
molded body and the covering material by heat seal rolls, thereby
forming a heat seal part. Moreover, at least one of the substrate
and the covering material is air-permeable. Incidentally, an
air-permeable sticky layer may be provided in the heat seal part
side of the covering material. An air-permeable sticky layer may be
provided for the heat generating composition molded body as
provided on the substrate by a melt blow method or the like.
[0209] Furthermore, the temporary adhesion roll may be at least one
member selected from a die roll and a flat roll in which at least
the surface thereof is flexible. The surface of the roll may be any
of a plain surface, a patterned surface or a mixture of plain and
patterned surfaces.
[0210] Next, the temporary adhesion will be described with
reference to FIGS. 7 to 13.
[0211] FIG. 7(a) and FIG. 7(b) each shows an example of a temporary
adhesion plate. A heat generating composition molded body or the
like is accommodated in a concave 17B, and a temporary adhering
part is formed by 17A.
[0212] FIG. 8(a) is an oblique view of a temporary adhesion roll 18
in the MD direction; and FIG. 8(b) is a side view thereof. In the
drawings, a temporary adhering part is formed by 18A, and a heat
generating composition molded body or the like is accommodated in
18B.
[0213] FIG. 9(a) is an oblique view of a roll 18 for temporarily
adhering an end part of a substrate in the MD direction or an end
part of a substrate in the MD direction and a top of a heat
generating composition molded body to a covering material. FIG.
9(b) is a cross-sectional view showing a roll 18 for temporarily
adhering an end part of a substrate 4 in the MD direction to a
covering material 5 and a part of a heat generating body 1. FIG.
9(c) is a cross-sectional view showing a roll 18 for temporarily
adhering an end part of a substrate in the MD direction and a top
of a heat generating composition molded body 1A to a covering
material 5 and a part of a heat generating body 1. FIG. 9(d) is an
oblique view showing a part of a heat generating body 1 in which an
end part of a substrate in the MD direction and a top of a heat
generating composition molded body 7 are adhered to a covering
material 5. In FIG. 9(a), a temporary adhering part is formed by
18A. Incidentally, the heat generating composition molded body or
the like is accommodated in a space between adjacent 18A and 18A;
and in FIG. 9(b), the heat generating composition molded body is
not pressed; in FIG. 9(c), the heat generating composition molded
body is pressed. In FIG. 9(d), the end part of the substrate in the
MD direction is in a temporarily adhered state by the temporary
adhesion roll 18, and thereafter, the surroundings of the heat
generating body including a space 7B between the adjacent heat
generating composition molded bodies 7 and the foregoing temporary
adhering part are heat sealed by a heat seal roll. In FIG. 9(e), a
covering material is sagged between the heat generating composition
molded bodies 7 and 7 by a temporary adhesion roll, the
surroundings of the heat generating body are in a temporarily
adhered state, and thereafter, the surroundings of the heat
generating body including a space 7B between the adjacent heat
generating composition molded bodies 7 and 7 and the foregoing
temporary adhering part are heat sealed. It is possible to prevent
cutting in seal by this sagging.
[0214] FIG. 10 is an oblique view of a temporary adhesion roll 18
in the TD direction, and a temporary adhering part is formed by
18A.
[0215] FIG. 11 is a plan view of a temporary adhesion roll 18
having a rectangular temporary adhering part, and the temporary
adhering part is formed by 18A. When pressed by this roll 18, as
shown in FIG. 12, a temporary adhering part 7 is formed and then
heat sealed together with a portion 7A which is not temporarily
adhered.
[0216] Further, FIG. 13 is a plan view of a temporary adhesion roll
18 having an elliptical exothermic part.
[0217] FIG. 14 is a plan view of a heat generating body having a
circular sectioned part in an exothermic part as temporarily
adhered by a temporary adhesion roll in which the elliptical
portion of the temporary adhesion roll as shown in FIG. 13 is
formed in a true circle shape, which is provided with a heat seal 8
after the temporary adhesion.
[0218] FIGS. 15 to 17 are each a view explaining collapse and/or
deadhesion of a heat generating body.
[0219] FIG. 15 is a cross-sectional view of a deadhesion plate 22
having a deadhering convex 22A and capable of achieving collapse
and/or deadhesion. As shown in FIG. 17, a heat generating
composition molded body or the like is pressed by this deadhering
convex 22A via a covering material 5. Also, FIG. 16 is a
cross-sectional view of a deadhesion plate 22 provided with a
deadhering convex 22C as in FIG. 15 on the surface of a circular
roll and capable of achieving collapse and/or deadhesion.
[0220] FIG. 17(a) is a schematic cross-sectional view showing
collapse and deadhesion using a deadhesion roll 22B having a
deadhering convex 22C and capable of achieving collapse and/or
deadhesion; and as shown in the left-hand portion of this drawing,
a heat generating composition molded body 1A is covered by a
covering material 5, and a space is formed in the periphery
thereof. Furthermore, a heat seal 8 is partially provided in the
covering material 5 and a substrate 4. In this state, when the
deadhering convex 22C presses the upper surface of the covering
material 5, the heat generating composition molded body is
collapsed and accommodated within the foregoing space; and as shown
in the right-hand portion of this drawing, the heat generating
composition molded body 3 is pushed into the heat seal part 8.
Incidentally, FIG. 17(b) shows an example not having the deadhering
convex 22C.
[0221] After these seal steps, a heat generating body is produced
through a cutting step, etc. These seal step and cutting step and
the like may be properly selected and employed from conventional
methods and devices. Incidentally, in the case of a molding system,
there are enumerated force-through molding using a trimming die,
trimming die cast molding, and cast molding using a concave casting
die.
[0222] According to this method, since the periphery of the
substrate and the covering material are temporarily adhered with an
adhesive layer and then heat sealed, the heat generating
composition molded body does not cause deviation so that
complicated heat sealing can be achieved at high speed.
[0223] With respect to the production process of a heat generating
body according to the molding system, there are a conventional heat
generating body in which the exothermic part is made of a single
part and a heat generating body having a gathered exothermic part
in which the exothermic part is sectioned and made of two or more
sectional parts. As the production process of such a heat
generating body, any molding method using a die is employable.
Examples thereof include a force-through molding method and a cast
molding method. In the case where the exothermic part is made of a
single part, molding may be carried out by using a trimming die or
a concave casting die capable of molding a single exothermic part.
In the case where the exothermic part is sectioned and made of two
or more sectional parts, molding may be carried out by using a
trimming die or a concave casting die capable of molding a gathered
exothermic part made of two or more plural sectional exothermic
parts. In the production of a heat generating body according to the
molding system, it is possible to produce a heat generating body at
a speed of three times or more as compared with a filling system.
Thus, by employing the molding system, it is possible to largely
reduce costs due to an improvement of the production speed.
However, a material cannot be used as the heat generating
composition to be used unless it is a moldable heat generating
composition.
[0224] The "force-through molding method" as referred to herein
means, for example, a continuous formation method in which by using
a molding machine for laminating a heat generating composition
molded body having a trimming die shape on a longitudinal substrate
by using a trimming die and a rotary seal unit capable of covering
the laminate by a longitudinal covering material and sealing (by
heat sealing, contact bonding sealing, or heat contact boding
sealing) a desired sectioned part and the peripheries of the
substrate and the covering material, the peripheries of the heat
generating composition molded body and a necessary part of the
sectioned part are heat sealed via the seal unit and subjected to a
seal treatment.
[0225] The "trimming die cast molding" as referred to herein means
a method in which by using a trimming die, one surface of a cavity
is covered by a roll, etc., a heat generating composition is filled
in the cavity, a longitudinal substrate is then placed on the other
surface, and a heat generating composition molded body is laminated
on the substrate.
[0226] The "cast molding method" as referred to herein means, for
example, a continuous molding method in which by using a molding
machine for laminating a heat generating composition molded body on
a longitudinal substrate by filling in a concave and moving into a
substrate by a drum-type body of rotation having a concave and a
rotary seal unit capable of covering the laminate by a longitudinal
covering material and sealing (by heat sealing, contact bond
sealing, or heat contact bond sealing) a desired sectioned part and
the peripheries of the substrate and the covering material, the
peripheries of the active heat generating composition molded body
and a necessary part of the sectioned part are heat sealed via the
seal unit and subjected to a seal treatment.
[0227] Furthermore, examples of the heat generating body using the
heat generating composition include a heat generating body which is
constituted such that the heat generating composition molded body
is laminated between a substrate and an air-permeable packaging
material constituted of a covering material.
[0228] The temporary adhesion can be carried out by using a
temporary adhesion plate, a temporary adhesion roll, etc., covering
it by the substrate and/or the heat generating composition and/or
the heat generating composition molded body and a covering agent,
and contact bonding a desired region by pressurization,
pressurization under heating, etc. The pressurization under heating
can be carried out by passing through a heat press machine or heat
rolls. The pressurization or pressurization under heating can be
carried out by using a plain or flat roll. However, in order to
enhance a shape fixing effect while keeping the flexibility of a
sheet-like material, it is preferable that at least one surface of
the pressurizing surface or pressurizing surface under heating is
embossed. The shape of embossing is not particularly limited.
Usually, examples thereof include a wavy form, a hexagonal form, a
ring-like form, a polka-dotted form, and a reticulate form. It is
preferable that the heat generating composition powder easily keeps
away into a non-compressed part at the time of pressurization or
pressurization under heating. A rate of the area of projections on
the embossed surface is not particularly limited. It is usually
from 0.5 to 60.0%, and preferably from 5.0 to 40.0%. Furthermore,
with respect to the material quality of the surface of the
temporary plate and temporary roll, materials ranging from a rigid
one to a flexible one can be used. In the case of the planar or
flat roll, ones in which at least the surface thereof is flexible
and the surface can be deformed are preferable. Examples thereof
include raw materials such as a felt, a non-woven fabric, and a
flexible rubber.
[0229] The temperature and pressure condition for the
pressureization or pressurization under heating varies depending
upon the material quality of the substrate or covering material and
the softening temperature and/or the melting point of the adhesive
or heat seal material. For example, in the case of using a heat
roll, usually, the temperature is from about 70 to 300.degree. C.,
and the linear pressure is from about 0.1 to 250 kg/cm. In this
way, the heat seal material on the surface of the laminate which
comes into contact with a projected part in the pressurized state
is molten and fixed with respect to the shape.
[0230] Furthermore, the thickness of the sticky layer is not
limited so far as the temporary adhesion and the heat sealing can
be achieved. It is preferable that the total thickness of the heat
seal layers of the substrate and the covering material is the
thickness of the adhesive layer or more.
[0231] The "deadhesion" as referred to herein means that the state
that the substrate and the covering material are adhered to each
other via the sticky layer is removed, thereby releasing the
adhesive state between the substrate and the covering material. It
does not matter whether or not after deadhesion, an inclusion is
present between the substrate and the covering material. There is
enumerated a method in which a part of the temporary adhering part
where the substrate and the covering material are temporarily
adhered to each other via the sticky layer is heat sealed and the
heat generating composition is moved into a non-heat sealed region
between the substrate and the covering material, thereby making the
space between the substrate and the covering material in a
non-adhesive state.
[0232] What compatibility at the time of heat sealing is good means
that when heat sealed, the heat sealing is not hindered and
separation does not occur. That is, in the heat seal part, the
sticky layer and the heat seal layer are not necessarily required
to be completely fused, but it is only required that the heat seal
strength after heat sealing is higher than the contact bonding seal
strength. It is to be noted that if air does not invade into the
heat generating composition from the heat seal part, the substrate
and the covering material are heat sealed.
[0233] Furthermore, after temporary adhesion, by heat sealing in a
heat seal width narrower than the temporary adhesion width and then
deadhering the non-heat sealed temporary adhering part, heat
sealing is completed in a substantially narrow heat seal width.
According to the invention, it has become possible to achieve heat
sealing in an extra-fine width. In particular, in a heat generating
body having an exothermic part constituted of a sectional
exothermic part and a sectioned part (heat seal part), such is an
important structure and technology in the case of making
flexibility consistent with exothermic characteristics. When the
sectioned part width which is the heat seal width is large, the
space between the sectional exothermic parts is widened, whereby
unevenness in temperature of the exothermic part becomes large.
[0234] According to the invention, it becomes possible to prepare a
heat generating body having an exothermic part wherein the space
between the sectional exothermic parts is made minimum, and the
sectional exothermic parts are not separated from so far. Thus, a
heat insulation effect between the sectional exothermic parts is
increased so that the exothermic time becomes long.
[0235] The "water mobility value" as referred to herein is a value
showing an amount of surplus water which can transfer to the
outside of the heat generating composition in water present in the
heat generating composition. This water mobility value will be
described below with reference to FIGS. 20 to 24.
[0236] As shown in FIG. 20, a filter paper 29 of No. 2 (second
class of JIS P3801) in which eight lines are drawn radiating from
the central point with an interval of 45.degree. is placed on a
stainless steel plate 33 as shown in FIGS. 21 and 22; a template 30
having a size of 150 mm in length.times.100 mm in width and having
a hollow cylindrical hole 31 having a size of 20 mm in inner
diameter.times.8 mm in height is placed in the center of the filter
paper 29; a sample 32 is placed in the vicinity of the hollow
cylindrical hole 31; and a stuffer plate 26 is moved on and along
the template 30 and inserted into the hollow cylindrical hole 31
while stuffing the sample 32, thereby leveling the sample (force-in
die molding).
[0237] Next, as shown in FIG. 23, a non-water absorptive 70
.mu.m-thick polyethylene film 28 is placed so as to cover the hole
31, and a flat plate 27 made of stainless steel having a size of 5
mm in thickness.times.150 mm in length.times.150 mm in width is
further placed thereon and held for 5 minutes such that an
exothermic reaction is not caused.
[0238] Thereafter, a shown in FIG. 23, the filter paper 29 is taken
out, and an oozed-out locus of the water or aqueous solution is
read as a distance 34 (unit: mm) from a periphery 35 as an edge of
the hollow cylindrical hole to an oozed-out tip along the radiating
lines. Similarly, a distance 34 from each of the lines is read, and
eight values in total are obtained. Each of the eight values (a, b,
c, d, e, f, g and h) which are read out is defined a sa measured
water content value. An arithmetic average value of the eight
measured water content values is defined as a water content value
(mm) of the sample.
[0239] Furthermore, the water content for the purpose of measuring
a real water content value is defined as a compounded water content
of the heat generating composition corresponding to the weight of
the heat generating composition having a size of 20 mm in inner
diameter.times.8 mm in height or the like, similar measurement is
conducted only with water corresponding to that water content, and
a value as calculated in the same manner is defined as a real water
content value (mm). A value obtained by dividing the water content
value by the real water content value and then multiplying with 100
is a water mobility value.
[0240] That is, the water mobility value is represented by the
following expression.
(Water mobility value)={[Water content value (mm)]/[(Real water
content value (mm))].times.100
[0241] With respect to the same sample, five points are measured,
and the five water mobility values are averaged, thereby defining
an average value thereof as a water mobility value of the
sample.
[0242] In the invention, a heat generating body can be formed only
by laminating a heat generating composition molded body obtained by
molding a heat generating composition having surplus water with a
water mobility value of from 0.01 to 20 on a substrate, covering a
covering material thereon, and sealing at least the periphery of
the heat generating composition molded body. After accommodating it
in a packaging material such as a substrate and a covering
material, it is not necessary to add water. Accordingly, since the
process is remarkably simplified, the invention is superior in view
of the costs.
[0243] In the invention, the water mobility value (0 to 100) is
preferably from 0.01 to 20, more preferably from 0.01 to 18,
further preferably from 0.01 to 15, still further preferably from
0.01 to 13, even further preferably from 1 to 13, and even still
further preferably from 3 to 13.
[0244] In a heat generating body using a heat generating
composition molded body obtained by molding a moldable heat
generating composition containing surplus water as a connecting
substance according to the invention, the heat generating
composition contains an appropriate amount of surplus water
expressed by a water mobility value of from 0.01 to 20 as the
connecting substance without using a flocculant aid, a dry binding
agent, a flocculating agent, etc.
[0245] It is assumed that when the amount of surplus water in the
heat generating composition is appropriate, the surplus water
causes hydration against hydrophilic groups in the components of
the composition due to a bipolar mutual action or hydrogen bond,
etc. and that it is present even in the surroundings of hydrophobic
groups while having high structural properties. Thus, it is assumed
that the heat generating composition becomes in a state of a mud
ball, thereby revealing moldability. This is connecting water as a
connecting substance in some meaning. Besides, there is water in a
state called as free water which can freely move, and it is thought
that when the surplus water increases, the structure is softened,
whereby the free water increases. Furthermore, controlling factors
which an iron powder causes an oxidation reaction are an amount of
existing water and a feed amount of oxygen to the surface of the
iron powder. It is said that in a degree of water adsorbing film
(less than 100 angstroms), the water is not sufficient and that the
oxidation rate is small. When the adsorbing film becomes about 1
.mu.m, the water content becomes sufficient. Furthermore, since the
thickness of the water film is thin, feed of oxygen onto the
surface of the iron powder becomes easy, whereby the oxidation rate
becomes large. It is assumed that when the film becomes thicker to
an extent that the adsorbing film exceeds 1 .mu.m, the feed amount
of oxygen is reduced. The present inventors have obtained knowledge
that the water mobility value expressing the optimal water content
at which moldability and oxidation rate in fixed levels or more are
revealed is from 0.01 to 20, leading to accomplishment of the
invention.
[0246] That is, by using an appropriate amount of surplus water,
the respective component particles are coupled with each other by a
surface tension of water, moldability is generated in the heat
generating composition, and the water does not substantially
function as a barrier layer. Thus, the heat generating composition
comes into contact with air to generate heat. In addition, by using
a heat generating composition using an active iron powder or an
active heat generating composition using an active iron powder, the
heat generating composition becomes a heat generating composition
having remarkably excellent exothermic rising properties and high
moldability. Furthermore, heat generation occurs without causing
transfer of the water in the heat generating composition molded
body as produced by a molding and laminating system into a
packaging material or water absorptive sheet. In addition, by
providing plural sectional exothermic parts of the heat generating
composition molded body as sectioned by seal parts, it is possible
to provide a heat generating body which has flexibility itself, is
excellent in installation in places where flexibility is required,
such as various places of a human body and curved bodies, and is
excellent in feeling for use.
[0247] Furthermore, in the substrate, the covering material and the
heat generating composition molded body, by temporarily adhering at
least the covering material and the heat generating composition
molded body to each other via a sticky layer and then heat sealing
the periphery of the heat generating composition molded body and
the surroundings of the heat generating body, certainty of heat
seal is improved so that it becomes possible to design to make the
production speed of a heat generating body high and make the heat
seal width small.
[0248] The "moldability" as referred to in the invention exhibits
that a molded body of the heat generating composition having a
cavity or concave die shape is formed by force-through molding
using a trimming die having a cavity or cast molding using a
concave die, whereby after molding including mold release, the
molding shape of the heat generating composition molded body is
held.
[0249] When the moldability is revealed, since the shape is held
until the heat generating composition molded article is at least
covered by a covering material and a seal part is formed between
the substrate and the covering material, sealing can be achieved in
the periphery of the shape with a desired shape. Also, since
so-called "spots" which are a collapsed piece of the heat
generating composition are not scattered in the seal part, the
sealing can be achieved without causing cutting in seal. The
presence of the spots causes insufficient sealing.
1) Measurement Device:
[0250] With respect to the measurement device, a stainless
steel-made molding die (a plate having a size of 2 mm in
thickness.times.200 mm in length.times.200 mm in width and having a
cavity as treated by R5 in four corners of 60 mm in length.times.40
mm in width in a central part thereof) and a fixable leveling plate
are disposed above a travelable endless belt, and magnets (two
magnets having a size of 12.5 mm in thickness.times.24 mm in
length.times.24 mm in width are disposed in parallel) are disposed
under the endless belt.
[0251] The magnets should cover a region of the leveling plate and
the vicinity thereof and a region larger than a region covered by a
cut side (40 mm) vertical to the advancing direction of the cavity
of the molding die.
2) Measurement Method:
[0252] With respect to the measurement method, a stainless steel
plate having a size of 1 mm in thickness.times.200 mm in
length.times.200 mm in width is placed on the endless belt of the
measurement device, a polyethylene film having a size of 70 .mu.m
in thickness.times.200 mm in length.times.200 mm in width is placed
thereon, and a stainless steel-made molding die is further placed
thereon.
[0253] Thereafter, a leveling plate is fixed in a position of the
cavity of the molding die of 50 mm far from the end portion in the
advancing direction of the endless belt, 50 g of a heat generating
composition is then placed in the vicinity of the leveling plate
between the leveling plate and the cavity, and the heat generating
composition is filled in the cavity of the molding die while
leveling it by moving the endless belt at 1.8 m/min. After the
molding die has completely passed through the leveling plate, the
traveling of the endless belt is stopped. Next, the molding die is
removed, and a heat generating composition molded body as laminated
on the polyethylene film is observed.
3) Judgment Method:
[0254] With respect to the judgment method, in the surroundings of
the heat generating composition molded body, in the case where any
collapsed piece of the heat generating composition molded body
exceeding a maximum length of 800 .mu.m is not present and the
number of collapsed pieces of the heat generating composition
molded body having a maximum length of from 300 to 800 .mu.m is not
more than 5, it is to be noted that the heat generating composition
has moldability.
[0255] The moldability is an essential property for a heat
generating composition to be used in the molding system. If the
heat generating composition does not have moldability, it is
impossible to produce a heat generating body by the molding
system.
[0256] The heat generating composition of the invention has
resistance to compression. The "resistance to compression" as
referred to herein means that a heat generating composition
compressed body obtained by compressing a heat generating
composition molded body as accommodated in a molding die within the
die to such an extent that the thickness is 70% of the die
thickness holds 80% or more of exothermic rising properties of the
exothermic rising properties of the heat generating composition
molded body before compression (a difference in temperature between
one minute and 3 minutes after starting a heat generation test of
the heat generating composition).
[0257] Here, the measurement method of exothermic rinsing
properties for the resistance to compression will be described
below.
1. Heat Generating Composition Molded Body:
[0258] 1) A magnet is provided in the vicinity of a central part of
the back side of a polyvinyl chloride-made supporting plate (5 mm
in thickness.times.600 mm in length.times.600 mm in width) of a
footed supporting table so as to cover a cavity shape of a molding
die.
[0259] 2) A temperature sensor is placed on the central part the
surface of the supporting plate.
[0260] 3) A polyethylene film (25 .mu.m in thickness.times.250 mm
in length.times.200 mm in width) as provided with an adhesive layer
having a thickness of about 80 .mu.m is stuck onto the supporting
plate via a sticky layer such that the center of the polyethylene
film is positioned at the sensor.
[0261] 4) On an underlay plate (280 mm in length.times.150 mm in
width.times.50 .mu.m to 2 mm in thickness), a polyethylene film
(230 mm in length.times.155 mm in width.times.25 .mu.m to 100 .mu.m
in thickness) is placed such that one end of the polyethylene film
is projected by about 20 mm outside the underlay plate and that one
end thereof in the length direction is substantially coincident
with one end of the underlay plate.
[0262] 5) A template (230 mm in length.times.120 mm in
width.times.3 mm in thickness) having a cavity (80 mm in
length.times.50 mm in width.times.3 mm in height) is placed on the
polyethylene film placed on the underlay plate; a template is
placed on the polyethylene film such that one end thereof in the
length direction is fitted to one end where the underlay plate and
the polyethylene film are coincident with each other and that in
the width direction, one end part of the width of the template is
placed at a position of the central part by about 20 mm far from an
opposing end to the side where the polyethylene film is projected
outward from the underlay plate. Next, the resulting assembly is
placed on the supporting plate together with the underlay
plate.
[0263] 6) A sample is placed in the vicinity of the cavity; a
force-in die plate is moved along the molding die; the sample is
charged into the cavity while stuffing; and the sample is leveled
while stuffing along the template plane (force-in die molding),
thereby filling the sample in the die.
[0264] 7) Next, the magnet beneath the supporting plate is removed;
the end portion of the projected polyethylene film is pressed; the
underlay plate is removed; and the temperature measurement is
started.
2. Heat Generating Composition Compressed Body:
[0265] 1) to 6) are the same as in the case of the heat generating
composition molded body.
[0266] 8) A die having a convex having a thickness of 0.9 mm which
can substantially tightly come into the cavity in relation of the
cavity with an unevenness is fitted to the cavity and compressed by
a roll press or plate press to prepare a heat generating
composition compressed body having a thickness of 2.1 mm
(compressed to 70% of the die thickness) within the die.
[0267] 9) The resulting assembly is placed on the supporting plate
together with the underlay plate; the magnet beneath the supporting
plate is removed; the end portion of the projected polyethylene
film is pressed; the underlay plate is removed; and the temperature
measurement is started.
[0268] With respect to the measurement of the exothermic
temperature, the temperature is measured for 5 minutes at a
measurement timing of 2 seconds using a data collector, and
resistance to compression is judged in terms of a difference in
temperature between after elapsing one minute and after elapsing 3
minutes.
[0269] The thickness after compression is preferably from 50 to
99.5%, more preferably from 60 to 99.5%, and further preferably
from 60 to 95% of the die thickness.
[0270] Incidentally, in the invention, it is to be noted that the
heat generating composition molded body includes a heat generating
composition compressed body.
[0271] The particle size of the water-insoluble solid component
constituting the moldable heat generating composition of the
invention is not limited so far as the heat generating composition
has moldability. In the case where any one of length, width and
height as the size of the heat generating composition molded body
as molded from the heat generating composition is small, the
moldability is improved by making the particle size small.
[0272] In addition, it is preferable in view of molding that the
particle size of the solid component constituting the moldable heat
generating composition is small. A maximum particle size of the
water-insoluble solid component exclusive of the reaction
accelerator and water in the components constituting the moldable
heat generating composition is preferably not more than 2.5 mm,
more preferably not more than 930 .mu.m, further preferably not
more than 500 .mu.m, still further preferably not more than 300
.mu.m, even further preferably not more than 250 .mu.m, and even
still further preferably not more than 200 .mu.m. Moreover, 80% or
more of the particle size of the solid component is usually not
more than 500 .mu.m, preferably not more than 300 .mu.m, more
preferably not more than 250 .mu.m, further preferably not more
than 200 .mu.m, still further preferably not more than 150 .mu.m,
and even further preferably not more than 100 .mu.m.
[0273] Incidentally, with respect to the particle size of the
water-insoluble solid component, separation is conducted using a
sieve, and the particle size of the component which has passed
through the sieve is calculated from an opening of the sieve. That
is, sieves of 8, 12, 20, 32, 42, 60, 80, 100, 115, 150, 200, 250
and 280 meshes and a receiving dish are combined in this order from
up to down. About 50 g of water-insoluble solid component particles
are placed on the uppermost 8-mesh sieve and shaken for one minute
using an automatic shaker. Weights of the water-insoluble solid
component particles on each of the sieves and the receiving dish
are weighed. The total amount thereof is defined as 100%, and the
particle size distribution is determined from weight fractions.
When the sum of all receiving dishes under the sieve of a specific
mesh size becomes 100% which is the total sum of the particle size
distribution, the size (.mu.m) calculated from the opening of the
specific mesh is defined as the particle size of the
water-insoluble solid component. Incidentally, each of the mesh
sieves may be combined with other mesh sieves. Here, the particles
which have passed through a 16-mesh sieve are defined to have a
particle size of not more than 1 mm; the particles which have
passed through a 20-mesh sieve are defined to have a particle size
of not more than 850 .mu.m; the particles which have passed through
a 48-mesh sieve are defined to have a particle size of not more
than 300 .mu.m; the particles which have passed through a 60-mesh
sieve are defined to have a particle size of not more than 250
.mu.m; the particles which have passed through a 65-mesh sieve are
defined to have a particle size of not more than 200 .mu.m; the
particles which have passed through an 80-mesh sieve are defined to
have a particle size of not more than 180 .mu.m; the particles
which have passed through a 100-mesh sieve are defined to have a
particle size of not more than 150 .mu.m; the particles which have
passed through a 115-mesh sieve are defined to have a particle size
of not more than 120 .mu.m; the particles which have passed through
a 150-mesh sieve are defined to have a particle size of not more
than 100 .mu.m; and the particles which have passed through a
250-mesh sieve are defined to have a particle size of not more 63
.mu.m, respectively. The same is applicable to mesh sizes of less
than these mesh sizes.
[0274] Furthermore, the heat generating composition can be
classified into a powder, a granulate heat generating composition
(having a water mobility value of less than 0.01), a moldable heat
generating composition (having a water mobility value of from 0.01
to 20), and a sherbet-like heat generating composition (having a
water mobility value exceeding 20 but not more than 50) depending
upon the state of adjustment of the water content or surplus water.
The heat generating composition as classified depending upon the
water mobility value is as described previously.
[0275] The "heat generating mixture" as referred to herein is a
material obtained by subjecting a reaction mixture containing, as
essential components, an iron powder, a carbon component, a
reaction accelerator and water and having a water content of from 1
to 30% by weight and a water mobility value of less than 0.01 to a
contact treatment with an oxidizing gas under fluidization, thereby
keeping a temperature of the reaction mixture after the contact at
40.degree. C. or higher for 2 seconds or more. So far as some
change is caused in the reaction mixture by the contact treatment
with an oxidizing gas, the iron powder is not always required to be
oxidized. However, it is preferable that the iron powder is
oxidized. In that case, it is preferable that the iron powder
becomes an active iron powder.
[0276] The "active heat generating composition" as referred to
herein is a heat generating composition corresponding to any one of
the following (1) to (3).
[0277] (1) A heat generating composition prepared by contact
treating a reaction mixture containing, as essential components, an
iron powder, a carbon component, a reaction accelerator and water
with an oxidizing gas, or by adjusting the water content of the
oxidizing gas contact treated mixture by the addition of water or a
reaction accelerator aqueous solution.
[0278] (2) A heat generating composition prepared by contact
treating a reaction mixture containing, as essential components, an
iron powder, a carbon component, a reaction accelerator and water
and having a water content of from 1 to 30% by weight and a water
mobility value of less than 0.01 with an oxidizing gas and holding
the temperature of the reaction mixture at the time of contact at
40.degree. C. or more for 2 seconds or more, or by subjecting the
oxidizing gas and the contact treated mixture to adjustment of the
water content by adjusting the water content of the oxidizing gas
contact treated mixture by the addition of water or a reaction
accelerator aqueous solution.
[0279] (3) A heat generating composition containing, as essential
components, an iron powder, a carbon component, a reaction
accelerator and water, wherein an iron powder containing from 20 to
100% of an active iron powder is used as the iron powder.
[0280] The "moldable heat generating composition" as referred to
herein is a heat generating composition which contains, as
essential components, an iron powder, a carbon component, a
reaction accelerator and water but does not contain a flocculant
aid, a flocculant, an agglomeration aid, a dry binding material, a
dry binding agent, a dry binder, a sticky raw material, a thickener
and an excipient, contains surplus water so as to have a water
mobility value of from 0.01 to 20 and has moldability due to the
surplus water as a connecting substance, in which the water in the
heat generating composition does not function as a barrier layer,
the heat generating composition being capable of causing an
exothermic reaction upon contact with air.
[0281] It is preferable that at least one of the foregoing
packaging materials is made of a raw material preferably having a
breaking strength of 400 g/mm.sup.2 or more, more preferably 500
g/mm.sup.2 or more, further preferably 1,000 g/mm.sup.2 or more,
and still g/mm 2 further preferably 2,000 or more at 25.degree. C.
and having a breaking elongation of 100% or more at 90.degree. C.
Furthermore, though the thickness of the packaging material is not
limited so far as the foregoing breaking elongation is secured, it
is preferably 10 .mu.m or more, more preferably from 10 to 500
.mu.m, further preferably 10 to 300 .mu.m, still further preferably
from 10 to 250 .mu.m, and even further preferably from 50 to 250
.mu.m.
[0282] Laminates of a non-woven fabric and a film-like material of
a thermoplastic resin are preferably enumerated.
[0283] At least one packaging material is a laminate of a fibrous
material and a film-like material and is made of a raw material
which is heat sealable and flexible. Furthermore, this packaging
material at least has a breaking strength of 500 g/mm.sup.2 or more
under circumstances of from 25 to 60.degree. C. and a breaking
elongation of 100% or more at 90.degree. C. In a heat generating
body using this packaging material of the invention, the sectional
exothermic parts containing a heat generating composition molded
body or a heat generating composition compressed body as a
compressed body of the heat generating composition molded body have
a high bending resistance, and the sectioned parts as a heat seal
part, which are present therebetween and do not contain a heat
generating composition molded body or a heat generating composition
compressed body (hereinafter referred to as "heat generating
composition molded body") as a compressed body of the heat
generating composition molded body have a low bending resistance.
Since the exothermic part comprising a sectional exothermic part
and a sectioned part can keep the bending resistance at a
temperature of from about 0.degree. C. to about 80.degree. C., the
sectioned part functions as a hinge and is preferentially bent over
the sectional exothermic part. In the heat generating body
comprising a sectional exothermic part and a sectioned part, the
sectioned part at least functions as a hinge at from the normal
temperature to the temperature at the time of heating (from about
23.degree. C. to about 50.degree. C.) and is preferentially bent
over the sectional exothermic part. A satisfactory difference of
bending resistance at the time of heating is still kept. As a
result, the heat generating body keeps structural support of the
sectional exothermic part and has sufficient rigidity during the
production or during the use. On the other hand, the excellent
bending resistance at the time of heating is still kept.
[0284] In the heat generating body using the foregoing packaging
material for at least one of the substrate or covering material,
the heat generating composition molded body is laminated on a
substantially planar substrate, a covering material is covered
thereon, and the periphery of the heat generating composition
molded body is heat sealed, thereby forming a sectioned part as a
seal part. For example, in the case of using the foregoing
packaging material for a covering material, since the packaging
material is flexible and has a breaking strength of 500 g/mm.sup.2
or more at 25.degree. C. at least at from 25 to 60.degree. C.,
though it is bent, it has nerve and is able to surely cover the
heat generating composition molded body. In addition, since the
covering material has a breaking elongation of 100% or more at
90.degree. C. at the time of heat seal, the covering material does
not cause breakage by the temperature at the time of heat seal, is
free from cutting in seal, and is able to surely form a heat seal
part. Accordingly, in the heat generating body of the invention
having an exothermic part comprising a sectional exothermic part
containing a heat generating composition molded body and a
sectioned part not containing a heat generating composition molded
body, the sectional exothermic parts containing a heat generating
composition molded body or a heat generating composition compressed
body as a compressed body of the heat generating composition molded
body have a high bending resistance, and the sectioned parts as a
heat seal part, which are present therebetween and do not contain a
heat generating composition molded body or a heat generating
composition compressed body as a compressed body of the heat
generating composition molded body have a low bending resistance.
Since the exothermic part comprising a sectional exothermic part
and a sectioned part can keep the bending resistance at a
temperature of from about 0.degree. C. to about 80.degree. C., the
sectioned part functions as a hinge and is preferentially bent over
the sectional exothermic part. Since the heat generating body
comprising a sectional exothermic part and a sectioned part uses at
least a packaging material which is small in change at the
temperature of use, dimensional changes due to the packaging
material are small at the time of use, and structural flexibility
due to the bending resistance are kept. Thus, stable and
appropriate flexibility is kept in the heat generating body.
Furthermore, since in at least one of the both packaging materials,
a packaging material (usually a covering material) having a
breaking elongation of 100% or more at 90.degree. C. is used, in
the case of covering a substantially planar covering material on a
heat generating composition molded body as laminated on a
substantially planar substrate and heat sealing the periphery of
the heat generating composition molded body, wrinkles which
generate seal leakage are not generated so that a seal part free
from cutting in seal can be formed. The covering material may
partly have a convex.
[0285] In all of the foregoing working examples, the air-permeable
covering materials as used were a non-elastic body having a
permanent set of from 0.5% to 1.7% at a temperature between
25.degree. C. and 60.degree. C. and a laminate having a breaking
strength of 400 g/mm.sup.2 or more at 25.degree. C. and a breaking
elongation of 20% or more at 90.degree. C.
[0286] The "seal strength at 60.degree. C." as referred to herein
means an average value of respective maximum values obtained by
subjecting three samples to a measurement by taking a specimen of
25 mm.times.250 mm from a place of a subjective sealed sample to be
measured for the seal strength, allowing the specimen to stand
under circumstances at 60.degree. C. for 5 minutes, grasping it
under circumstances at 60.degree. C., and measuring a maximum
strength at intervals of 10 mm and at a tensile speed of 300
mm/min.
[0287] Here, the condition of the seal strength under circumstances
at 20.degree. C. is identical with that of the seal strength at
60.degree. C., except that the circumferential temperature for the
measurement is 20.degree. C.
[0288] The seal strength of the temporary adhering part is
preferably 0.5 kg/25 mm or more, more preferably from 0.5 to 1
kg/25 mm, further preferably from 0.5 to 0.9 kg/25 mm, and still
further preferably from 0.5 to 0.8 kg/25 mm under circumstances at
20.degree. C.; and the seal strength at 60.degree. C. is preferably
less than 0.8 kg/25 mm, more preferably 0.01 kg/25 mm or more but
less than 0.8 kg/25 mm, further preferably 0.01 kg/25 mm or more
but less than 0.5 kg/25 mm, and still further preferably 0.01 kg/25
mm or more but less than 0.4 kg/25 mm.
[0289] The sticky layer of the temporary adhering part is
constituted of an adhesive, has a seal strength at 60.degree. C. of
from 0.01 to 0.8 kg/25 mm, is able to stop the movement of the heat
generating composition molded body between the substrate and the
covering material, and makes it possible to achieve heat sealing at
high speed. In addition, if desired, warming may be carried out at
the time of temporary adhesion. It is preferable that the warming
is carried out under pressure at a temperature of not higher than a
melting point of a base polymer in a hot melt based adhesive for
forming the adhesive layer.
[0290] The seal strength under circumstances at 20.degree. C. of
the heat seal part which has been heat sealed after the temporary
adhesion is preferably 1.0 kg/25 mm or more, more preferably 1.2
kg/25 mm or more, further preferably 1.5 kg/25 mm or more, and
still further preferably from 1.5 to 3 kg/25 mm. Furthermore, the
seal strength at 60.degree. C. under circumstances at 60.degree. C.
is preferably 0.8 kg/25 mm or more, more preferably 1.0 kg/25 mm or
more, further preferably 1.2 kg/25 mm or more, and still further
preferably 1.5 kg/25 mm or more.
[0291] A raw material of the substrate or covering material is not
limited so far as it functions as an accommodating bag of the heat
generating composition. Usually, raw materials which are used in
chemical body warmers or heat generating bodies can be used.
Examples of the raw material include air-impermeable raw materials,
air-permeable raw materials, water absorptive raw materials,
non-water absorptive raw materials, non-extensible raw materials,
extensible raw materials, stretchable raw materials,
non-stretchable raw materials, foamed raw materials, non-foamed raw
materials, non-heat sealable raw materials, and heat sealable raw
materials. The raw material can be properly used depending upon a
desired utility in a desired form such as films, sheets, non-woven
fabrics, woven fabrics, and composites thereof.
[0292] In general, the substrate is made of an air-impermeable film
or sheet, and the covering material is made of an air-permeable
film or sheet or non-woven fabric, and vice versa. The both may be
air-permeable. As the underlay material, an air-permeable underlay
material and an air-impermeable underlay material may be used for
different purposes.
[0293] The packaging material of the accommodating bag may be of a
single-layered structure or multilayered structure, and its
structure is not limited. Furthermore, though the packaging
material is composed of at least a substrate and a covering
material, a packaging material for laminating the heat generating
composition molded body is the substrate, and a packaging material
for covering on the heat generating composition molded body is the
covering material regardless of whether the packaging material is
air-permeable or air-impermeable. An embodiment of a multilayered
structure in which an air-impermeable packaging material is the
substrate and an air-permeable packaging material is the covering
material will be hereunder described as one example. That is, in
this embodiment, the substrate is made of layer A/layer B, layer
A/layer B/layer C, or layer A/layer B/layer C/layer D; and the
covering material is made of layer F/layer G, layer E/layer F/layer
G, or layer F/layer H/layer G. Examples of the layer A include
thermoplastic resin films (for example, polyethylene), heat seal
layers (for example, polyethylene and EVA), and water absorptive
papers; examples of the layer B include non-woven fabrics of a
thermoplastic resin (for example, nylons), non-water absorptive
papers, water absorptive papers, thermoplastic resin films (for
example, polyethylene films, polypropylene films, polyester films,
and polyamide (for example, nylons) films), wicks (for example,
non-water absorptive papers and water absorptive papers); examples
of the layer C include adhesive layers, non-water absorptive
papers, water absorptive papers, thermoplastic resin films (for
example, polyethylene), non-slip layers, and non-woven fabrics of a
thermoplastic resin (for example, polyesters and nylons); examples
of the layer D include separators, thermoplastic resin films (for
example, polyethylene), and non-woven fabrics; examples of the
layer E include heat seal layers; examples of the layer F include
porous films or perforated films made of a thermoplastic resin (for
example, polyethylene), films made of a thermoplastic resin (for
example, polyethylene), non-water absorptive papers, and water
absorptive papers; examples of the layer G include non-woven
fabrics of a thermoplastic resin (for example, polyesters and
nylons); and examples of the layer H include non-water absorptive
papers and water absorptive papers. Examples of the substrate or
covering material include heat seal layer made of polyethylene
obtained by using a metallocene catalyst/polypropylene film,
polyethylene-made heat seal layer/polypropylene film, EVA-made heat
seal layer/polypropylene film, EVA-made heat seal
layer/polypropylene film/adhesive layer/separator, EVA-made heat
seal layer/polyethylene film/nylon non-woven fabric, non-woven
fabric/porous film, heat seal layer made of polyethylene obtained
by using a metallocene catalyst/polyethylene film/nylon non-woven
fabric, heat seal layer made of polyethylene obtained by using a
metallocene catalyst/polypropylene film/polypropylene non-woven
fabric, non-woven fabric/(paper and/or perforated (provided by a
needle or laser) film)/porous film, non-woven fabric/(paper and/or
porous film)/perforated (provided by a needle or laser) film, and
non-woven fabric/(paper and/or porous film)/non-woven fabric. A
method for laminating the respective layers is not limited. The
respective layers may be directly laminated; the respective layers
may be laminated via an air-permeable adhesive layer or a
laminating agent layer; and the respective layers may be laminated
by hot melt extrusion or the like. Furthermore, in the invention,
it is to be noted that polyethylene produced by using a metallocene
catalyst is also included in the polyethylene.
[0294] For example, in the case of laminating the foregoing raw
material such as non-woven fabrics and porous films via an
air-permeable sticky layer, examples of a method for forming the
air-permeable sticky layer include a method in which a sticky
substance is fibrillated by an appropriate system such as a curtain
spray system, a melt blow system or a slot spray system for blowing
and spreading a sticky substance via hot air under heat melting and
spread and accumulated on an appropriate supporting substrate made
of a porous film, an air-permeable substrate, a separator, etc.,
thereby forming a porous sticky layer.
[0295] A thickness of each of the substrate, the covering material,
the underlay material, and the raw material constituting the same
varies depending upon the utility and is not limited. The thickness
is usually from 5 to 5,000 .mu.m, preferably from 10 to 500 .mu.m,
and more preferably from 20 to 250 .mu.m.
[0296] The air-impermeable raw material is not limited so far as it
is air-impermeable. Examples thereof include films, sheets or
coatings made of a polymer (for example, polyethylene,
polypropylene, nylons, polyacrylates, polyesters, polyvinyl
alcohols, and ethylene-vinyl acetate copolymers) and laminates
thereof with a metal (including a semiconductor) compound (for
example, silicon oxide) or composite raw materials using the
same.
[0297] Of the foregoing air-impermeable raw materials, examples of
a film having high air impermeability include films provided with a
single layer or multiple layers of a thin film having a metal
including a semiconductor or a compound thereof provided on an
air-impermeable raw material film. Examples of the metal including
a semiconductor include silicon, aluminum, and alloys or mixtures
containing such a metal. Examples of the metal (including a
semiconductor) compound include oxides, nitrides and oxynitrides of
the foregoing metals or alloys or mixtures. Examples of the layer
include silicon oxide layers, aluminum oxide layers, and silicon
oxynitride layers; layers obtained by laminating an arbitrary layer
of these layers on a polyester-made film; and layers obtained by
further laminating a stretched polyolefin film (for example, a
biaxially stretched polypropylene film) thereon.
[0298] The air-permeable raw material is not limited so far as it
is air-permeable. Examples thereof include air-permeable films (for
example, porous films and perforated films); materials having air
permeability by themselves (for example, papers and non-woven
fabrics); materials prepared by laminating at least one of papers
and air-permeable films and non-woven fabrics so as to have air
permeability; materials prepared by providing an air-impermeable
packaging material comprising a non-woven fabric having a
polyethylene film laminated thereon with fine pores by using a
needle, etc. so as to have air permeability; non-woven fabric whose
air permeability is controlled by laminating a fiber and heat
bonding under pressure; porous films; and materials prepared by
sticking a non-woven fabric onto a porous film. The "perforated
film" as referred to herein is a film prepared by providing an
air-impermeable film (for example, polyethylene films) with fine
pores by using a needle so as to have air permeability.
[0299] The air permeability is not limited so far as the heat
generation can be kept. In the case of use in usual heat
generation, the air permeability is usually from 50 to 10,000
g/m.sup.2/24 hr, preferably from 70 to 5,000 g/m.sup.2/24 hr, more
preferably from 100 to 2,000 g/m.sup.2/24 hr, and further
preferably from 100 to 700 g/m.sup.2/24 hr in terms of moisture
permeability by the Lyssy method.
[0300] When the moisture permeability is less 50 g/m.sup.2/24 hr,
the heat value is small and a sufficient thermal effect is not
obtained, and therefore, such is not preferable. On the other hand,
when it exceeds 10,000 g/m.sup.2/24 hr, the exothermic temperature
is high so that a problem in safety may possibly be generated, and
therefore, such is not preferable. However, there is no limitation
even when the moisture permeability exceeds 10,000 g/m.sup.2/24 hr
depending upon the utility, or even in the use at a moisture
permeability closed to the open system, according to
circumstances.
[0301] The stretchable packaging material is not particularly
limited so far as it is stretchable. That is, it is only required
that the stretchable packaging material is stretchable as a whole.
The stretchable packaging material may be formed of a single
material or a composite material of stretchable substrates or a
combination of a stretchable substrate and a non-stretchable
substrate.
[0302] Examples of the stretchable packaging material include
single materials (for example, natural rubbers, regenerated
rubbers, synthetic rubbers, elastomers, and stretchable shape
memory polymers) and mixtures thereof, mixed materials or blended
materials of such a stretchable raw material and a non-stretchable
raw material or fabrics constituted of a combination of these
materials, films, yarns, strands, ribbons, tapes, and stretchable
films with a scrim structure.
[0303] The porous film is not limited and can be properly selected
among porous films obtained by stretching a film made of a
polyolefin based resin (for example, polyethylene, linear low
density polyethylene, and polypropylene) or a fluorine based resin
(for example, polytetrafluoroethylene) and a filler.
[0304] The non-woven fabric is not limited. Single non-woven
fabrics of a single fiber or composite fiber made of a material
such as rayon, nylons (polyamides), polyesters, polyacrylates,
polypropylene, vinylon, polyethylene, polyurethane, cupra, cotton,
cellulose, and pulp, or laminates of blended or accumulated fiber
layers of such fibers are useful. Furthermore, from the standpoint
of production process, dry non-woven fabrics, wet non-woven
fabrics, spunbonds, spunlaces, and the like can be used. Non-woven
fabrics made of a composite fiber having a core-sheath structure
are also useful. A non-woven fabric in the side which is brought
into contact with the skin is preferably a napping (fluffy)
non-woven fabric. Also, stretchable non-woven fabrics and
non-stretchable non-woven fabrics are useful.
[0305] The water absorptive raw material is not particularly
limited so far as it is a water absorptive film or sheet.
[0306] The water absorptive raw material is not particularly
limited so far as it has water absorption properties consequently
regardless of whether or not the raw material has water absorption
properties by itself.
[0307] Specific examples thereof include water absorptive foamed
films or sheets having water absorption properties (for example,
foamed bodies of water absorptive foamed polyurethane, etc.) or
papers, non-woven fabrics or woven fabrics formed of a fiber having
water absorption properties, non-woven fabrics or woven fabrics
containing a fiber having water absorption properties, and water
absorptive materials such as water absorptive porous films or
sheets. Besides, there are enumerated materials in which regardless
of the presence or absence of water absorption properties, a water
absorbing agent is contained, impregnated, kneaded, transferred or
carried on a foamed film or sheet, a non-woven fabric, a woven
fabric or porous film or sheet, thereby imparting or increasing
water absorption properties; and materials in which regardless of
the presence or absence of water absorption properties, a water
absorptive raw material such as water absorptive foamed films or
sheets, papers, non-woven fabrics, woven fabrics, and porous films
or sheets as cut in a planar shape according to the invention is
attached to one side or both sides of the material according to the
invention, thereby imparting water absorption properties.
[0308] In particular, in the heat generating body of the invention,
for the purpose of forming the plane which is brought into contact
with the skin into a comfortable plane by imparting water
absorption properties against sweat, etc., in order that in the
case of sweating, the sweat is absorbed, it is preferable that a
packaging material in the plane which is brought into contact with
the skin is constituted of a packaging material using a non-woven
fabric or a woven fabric containing, as the major component, a
water absorptive fiber having a water retention of 20% or more.
Examples of the water absorptive fiber having a water retention of
20% or more include cottons, silks, hemps, wools, polyacrylonitrile
based synthetic fibers, polyamide based synthetic fibers, polyvinyl
alcohol based synthetic fibers, acetate fibers, triacetate fibers,
and regenerated fibers. In addition, non-woven fabrics having a
highly water absorptive polymer held in a non-woven fabric can be
used as the non-woven fabric having excellent water absorption
properties. Incidentally, non-woven fabrics or woven fabrics
containing such a fiber as the major component are relatively good
with respect to the feeling against the skin.
[0309] In addition, highly water absorptive packaging materials
having high absorption properties of sweat can be used as the
packaging material. Examples thereof include non-woven fabrics
containing a fiber whose surface is coated with a highly water
absorptive resin, non-woven fabrics containing a hollow fiber
having a number of fine pores on the surface thereof, and non-woven
fabrics containing a fiber having a capillary action by forming a
number of pouches or plural layers in the cross-sectional
shape.
[0310] Besides, non-woven fabrics or films having a water
absorptive inorganic compound held on a non-sticky surface of a
packaging material can be used. Examples thereof include non-woven
fabrics resulting from holding a powder (for example, diatomaceous
earth, zeolite, and silica gel) on a non-woven fabric and films
resulting from holding a relatively large amount of a powder (for
example, silica and alumina) on a synthetic resin (for example,
polyethylene).
[0311] The fixing means is not limited so far as it has capability
for fixing a thermal packaging body for joint surroundings or a
material having an exothermic part to a prescribed part.
[0312] As the fixing means, an adhesive layer, a hook and eye, a
hook and button, a hook and loop fastener such as Velcro, a magnet,
a band, a string, and combination thereof can be arbitrarily
used.
[0313] Incidentally, in the case of a band, fixing means for
adjustment may be further constructed by a combination of a hook
and loop fastener and an adhesive layer.
[0314] Here, the "hook and loop fastener" as referred to herein has
a fastening function by a combination of a loop as a female
fastener with a male fastener capable of fastening the female
fastener thereto, which is known as trade names such as Magic Tape
(a registered trademark), Magic Fastener (a registered trademark),
Velcro Fastener, and Hook and Loop Tape. Examples of the material
having a loop function include non-woven fabrics and woven fabrics
of napped or hole-containing yarns. Such a material having a loop
function (female fastener function) may be covered on the surface
of a paddling forming the band, or the band may be constructed of
such a material itself. Although the hook member which is the male
fastener member is not particularly limited, examples thereof
include hook members formed of a polyolefin based resin (for
example, polyethylene and polypropylene), a polyamide, a polyester,
etc. Although the shape of the hook is not particularly limited, a
hook having a cross-sectional shape such as an I type, an inverted
L type, an inverted J type, and a so-called mushroom type is
preferable because it is easily hooked by the loop and does not
give an extreme stimulus to the skin. Incidentally, the hook may be
adhered to the entire area of a fastening tape, and only the hook
may be used as a fastening tape while omitting a tape
substrate.
[0315] The adhesive layer may contain at least one member selected
from additional components consisting of a water retaining agent, a
water absorptive polymer, a pH adjusting agent, a surfactant, an
organosilicon compound, a hydrophobic polymer compound, a
pyroelectric substance, an antioxidant, an aggregate, a fibrous
material, a moisturizer, a functional substance, and a mixture
thereof.
[0316] The adhesive of the invention is classified into a
non-hydrophilic adhesive, a mixed adhesive, and a hydrophilic
adhesive (for example, a gel).
[0317] The adhesive constituting the adhesive layer is not limited
so far as it has an adhesive strength necessary for adhering to the
skin or clothes. Adhesives of every form such as a solvent based
adhesive, an aqueous adhesive, an emulsion type adhesive, a hot
melt type adhesive, a reactive adhesive, a pressure-sensitive
adhesive, a non-hydrophilic adhesive, and a hydrophilic adhesive
are employable.
[0318] The adhesive layer includes one layer of a non-hydrophilic
adhesive constituted of the non-hydrophilic adhesive and
non-hydrophilic adhesive layers constituted of the non-hydrophilic
adhesive.
[0319] It is to be noted that a material whose water absorption
properties are improving by containing a water absorptive polymer
or a water retaining agent in the non-hydrophilic adhesive layer is
dealt as the non-hydrophilic adhesive layer. A hot melt based
adhesive may be provided between the hydrophilic adhesive layer and
a substrate or a covering material.
[0320] Furthermore, in the case where the hydrophilic adhesive is
provided in a thermal packaging body for joint surroundings, there
is no limitation. After seal treating a thermal packaging body for
joint surroundings, a hydrophilic adhesive layer may be provided in
the thermal packaging body for joint surroundings.
[0321] Furthermore, the adhesive layer may or may not have air
permeability and may be properly selected depending upon the
utility. With respect to the air permeability, the adhesive layer
may be air-permeable as a whole. Examples there of include an
adhesive layer having air permeability as a whole of a region in
which an adhesive is partially present and a portion where no
adhesive is present is partially present.
[0322] In laminating an adhesive on an air-permeable substrate
and/or a covering material in a stratiform state as it is, examples
of a method for keeping its air permeability include a method in
which an adhesive layer is partially laminated by printing or
transferring an adhesive, thereby forming a non-laminated part as
an air-permeable part; a method in which an adhesive is transferred
in one direction while drawing a circle in a filament-like form or
properly moved in the two-dimensional directions by transferring in
a zigzag manner, whereby a space of the filament-like adhesive
keeps air permeability or moisture permeability or the adhesive is
foamed; and a method for forming a layer by a melt blow system.
[0323] Examples of the adhesive which constitutes the
non-hydrophilic adhesive layer include acrylic adhesives, polyvinyl
acetate based adhesives (for example, vinyl acetate resin based
emulsions and ethylene-vinyl acetate resin based holt melt
adhesives), polyvinyl alcohol based adhesives, polyvinyl acetal
based adhesives, vinyl chloride based adhesives, polyamide based
adhesives, polyethylene based adhesives, cellulose based adhesives,
chloroprene (neoprene) based adhesives, nitrile rubber based
adhesives, polysulfide based adhesives, butyl rubber based
adhesives, silicone rubber based adhesives, styrene based adhesives
(for example, styrene based hot melt adhesives), rubber based
adhesives, and silicone based adhesives. Of these, rubber based
adhesives, acrylic adhesives, and adhesives containing a hot melt
based polymer substance for the reasons that they are high in the
adhesive strength, are cheap, are good in long-term stability, and
are small in reduction of the adhesive strength even by providing
heat.
[0324] In addition to the base polymer, if desired, the adhesive
may be compounded with other components such as tackifiers (for
example, petroleum resins represented by rosins, chroman-indene
resins, hydrogenated petroleum resins, maleic anhydride-modified
rosins, rosin derivatives, and C-5 based petroleum resins), phenol
based tackifiers (especially, tackifiers having an aniline point of
not higher than 50.degree. C.; for example, terpene phenol based
resins, rosin phenol based resins, and alkylphenol based resins),
softeners (for example, coconut oil, castor oil, olive oil,
camellia oil, and liquid paraffin), softeners, anti-aging agents,
fillers, aggregates, adhesion adjusting agents, adhesion modifiers,
coloring agents, anti-foaming agents, thickeners, and modifiers,
thereby improving performance such as an improvement in adhesion to
nylon-made clothes and mixed yarn clothes.
[0325] Examples of the hot melt based adhesive include known hot
melt based adhesives imparted with adhesion. Specific examples
thereof include styrene based adhesives made of, as a base polymer,
an A-B-A type block copolymer (for example, SIS, SBS, SEBS, and
SIPS), vinyl chloride based adhesives made of, as a base polymer, a
vinyl chloride resin, polyester based adhesives made of, as a base
polymer, a polyester, polyamide based adhesives made of, as a base
polymer, a polyamide, acrylic adhesives made of, as a base polymer,
an acrylic resin, polyolefin based adhesives made of, as a base
polymer, a polyolefin (for example, polyethylene, super low density
polyethylene, polypropylene, ethylene-.alpha.-olefin copolymers,
and ethylene-vinyl acetate copolymers), 1,2-polybutadiene based
adhesives made of, as a base polymer, 1,2-polybutadiene, and
polyurethane based adhesives made of, as a base polymer,
polyurethane; adhesives made of a modified body of the foregoing
adhesive whose adhesion is improved or whose stability is changed;
and mixtures of two or more kinds of these adhesives. Adhesive
layers constituted of a foamed adhesive and adhesive layers
constituted of a crosslinked adhesive can also be employed.
[0326] The non-aromatic hot melt based adhesive is not limited so
far as it is made of, as a base polymer, a hot melt based adhesive
not containing an aromatic ring. Examples thereof include olefin
based hot melt based adhesives and acrylic hot melt based
adhesives. As the non-aromatic polymer which is the base polymer
not containing an aromatic ring, there are enumerated polymers or
copolymers of an olefin or a diene. Examples thereof include olefin
polymers. The olefin polymer includes polymers or copolymers of
ethylene or an .alpha.-olefin. Also, polymers resulting from adding
a diene (for example, butadiene and isoprene) as other monomer
there to may be employed.
[0327] The .alpha.-olefin is not limited so far as it is a monomer
having a double bond in the terminal thereof. Examples thereof
include propylene, butene, heptane, hexene, and octene.
[0328] The "aromatic hot melt based adhesive" as referred to herein
is a hot melt based adhesive whose base polymer contains an
aromatic ring. Examples thereof include styrene based hot melt
based adhesives represented by A-B-A type block copolymers.
[0329] In the foregoing A-B-A type block copolymers, the A block is
a non-elastic polymer block made of a monovinyl substituted
aromatic compound A such as styrene and methylstyrene; and the B
block is an elastic polymer block made of a conjugated diene such
as butadiene and isoprene. Specific examples thereof include a
styrene-butadiene-styrene block copolymer (SBS), a
styrene-isoprene-styrene block copolymer (SIS), and hydrogenated
types thereof (for example, SEBS and SIPS), and mixtures
thereof.
[0330] As a countermeasure for preventing a lowering of adhesive
strength caused due to an increase of water of the non-hydrophilic
adhesive layer, an adhesive layer obtained by further compounding a
water absorptive polymer in the non-hydrophilic adhesive can be
used.
[0331] The hydrophilic adhesive which constitutes the hydrophilic
adhesive layer is not particularly limited so far as it contains a
hydrophilic polymer or a water-soluble polymer as the major
component, has adhesion and is hydrophilic as an adhesive.
[0332] Examples of the constitutional components of the hydrophilic
adhesive include hydrophilic polymers (for example, polyacrylic
acid), water-soluble polymers (for example, poly(sodium acrylate)
and polyvinyl pyrrolidone), crosslinking agents (for example, dry
aluminum hydroxide and meta-silicic acid aluminic acid metal
salts), softeners (for example, glycerin and propylene glycol),
higher hydrocarbons (for example, soft liquid paraffin and
polybutene), primary alcohol fatty acid esters (for example,
isopropyl myristate), silicon-containing compounds (for example,
silicone oil), fatty acid glycerin esters (for example
monoglycerides), oily components (for example, vegetable oils such
as olive oil), antiseptics (for example, methyl p-hydroxybenzoate
and propyl p-hydroxybenzoate), solubilizing agents (for example,
N-methyl-2-pyrrolidone), thickeners (for example, carboxy-methyl
cellulose), surfactants (for example, polyoxyethylene hardened
castor oil and sorbitan fatty acid esters), hydroxycarboxylic acid
(for example, tartaric acid), excipients (for example, light
silicic anhydride, water absorptive polymers, and kaolin),
moisturizers (for example, D-sorbitol), stabilizers (for example,
sodium edetate, p-hydroxybenzoic acid esters, and tartaric acid),
crosslinking type water absorptive polymers, boron compounds (for
example, boric acid), and water. They may be used as an arbitrary
combination.
[0333] A temporary adhering seal part is formed via a sticky layer.
An adhesive which constitutes the sticky layer is a layer formed of
a polymer composition which is tacky at the normal temperature and
is not limited so far as it can be heat sealed after temporary
adhesion.
[0334] Furthermore, the foregoing adhesives of the sticky layer can
be used as the adhesive which constitutes the sticky layer as used
for temporary adhesion. Of these, non-hydrophilic adhesives are
preferable. With respect to the adhesive constituting the adhesive
layer, it is preferable that the adhesive is well compatible with a
heat seal material constituting a heat seal and that a melting
point of the base polymer of the adhesive is not higher than a
melting point of the heat seal material. Hot melt based adhesives
are especially preferable for hot melt based bonding agents.
Furthermore, in the case where the heat seal material is an olefin
based raw material, preferred examples thereof include olefin based
adhesives.
[0335] A bonding layer for fixing the air permeability adjusting
material is constituted of a bonding agent or an adhesive which is
usually used. In particular, an adhesive is useful, and the
foregoing adhesives for constituting the adhesive layer can be
used.
[0336] Furthermore, a method for providing a bonding layer is not
limited so far as the air permeability adjusting material can be
fixed. The bonding layer may be entirely provided or partially or
intermittently provided. Examples of its shape include various
shapes such as a network-like shape, a stripe-like shape, a
dot-like shape, and strip-like shape.
[0337] Furthermore, in the case where an adhesive layer is employed
as the hydrophilic adhesive layer, if there is a difference in a
water retaining force between the hydrophilic adhesive layer and
the heat generating composition molded body, transfer of water
occurs via a packaging material present therebetween such as a
substrate, thereby causing in-conveniences against the both. In
particular, the transfer of water occurs during the storage. In
order to prevent this, it is preferable that the packaging material
present therebetween at least has a moisture permeability of not
more than 2 g/m.sup.2/day in terms of a moisture permeability
according to the Lyssy method. By using this, in the case where the
heat generating body is accommodated in an outer bag as an
air-impermeable accommodating bag and stored, the transfer of water
can be prevented.
[0338] In the case where a hydrophilic adhesive layer is used as
the adhesive layer, the moisture permeability of a moisture-proof
packaging material provided between the heat generating composition
molded body and the hydrophilic adhesive layer is not limited so
far as the transfer of water can be prevented within the range
where the exothermic performance is not affected. The moisture
permeability according to the Lyssy method is usually not more than
2 g/m.sup.2/day, preferably not more than 1.0 g/m.sup.2/day, more
preferably not more than 0.5 g/m.sup.2/day, and further preferably
from 0.01 to 0.5 g/m.sup.2/day. These values are a value under a
condition under an atmospheric pressure at 40.degree. C. and 90%
RH. Incidentally, the moisture-proof packaging material can be used
as a substrate or a covering material and may be laminated singly
on a substrate, a covering material, or the like.
[0339] The moisture-proof packaging material is not limited so far
as the transfer of water between the heat generating composition
molded body and the hydrophilic adhesive layer can be prevented.
Examples thereof include metal vapor deposited films, vapor
deposited films of a metal oxide, metal foil-laminated films, EVOH
(ethylene/vinyl alcohol copolymer or ethylene/vinyl acetate
copolymer saponified product) based films, biaxially stretched
polyvinyl alcohol films, poly-vinylidene chloride coated films,
polyvinylidene chloride coated films obtained by coating
polyvinylidene chloride on a substrate film (for example,
polypropylene), metal foils such as an aluminum foil,
air-impermeable packaging materials obtained by vapor depositing or
sputtering a metal (for example, aluminum) on a polyester film
substrate, and packaging laminates using a transparent barrier film
of a structure in which silicon oxide or aluminum oxide is provided
on a flexible plastic substrate. The air-impermeable packaging
materials which are used in the outer bag, etc. can also be
used.
[0340] Furthermore, packaging materials such as moisture-proof
packaging materials as described in JP-A-2002-200108, the
disclosures of which can be incorporated herein by reference, can
be used.
[0341] In the case of using a water-containing hydrophilic adhesive
(for example, a gel) in the adhesive layer, in order to adjust the
moisture equilibrium between the heat generating composition and
the adhesive layer, the content of a reaction accelerator (for
example, sodium chloride) or a substance having a water holding
power (for example, a water absorptive polymer) in the heat
generating composition may be adjusted within the range of from 10
to 40% by weight, preferably from 15 to 40% by weight, and more
preferably from 15 to 30% by weight based on the heat generating
composition.
[0342] Furthermore, as the adhesive having good moisture
permeability and low stimulation to the skin, water-containing
adhesives (for example, hydrophilic adhesives and gels) as
described in JP-A-10-265373 and JP-A-9-87173, adhesives which can
be subjected to hot melt coating as described in JP-A-6-145050 and
JP-A-6-199660, and rubber based adhesives as described
JP-A-10-279466 and JP-A-10-182408, the disclosures of which are
totally incorporated herein by reference, are useful.
[0343] The functional substance which is contained in the adhesive
layer is not limited so far as it is a substance having any
function. There can be enumerated at least one member selected from
aromatic compounds, vegetable extracts, crude drugs, perfumes,
slimming agents, analgesics, blood circulation promoters, swelling
improvers, antibacterial agents, sterilizers, mold inhibitors, odor
eaters, deodorants, percutaneously absorptive drugs, fat-splitting
components, minus ion generators, far infrared ray radiants,
magnetic bodies, fomentations, cosmetics, bamboo vinegar, and wood
vinegar.
[0344] Specific examples thereof include aromatic compounds (for
example, menthol and benzaldehyde), vegetable extracts (for
example, mugwort extract), crude drugs (for example, moxa),
perfumes (for example, lavender and rosemary), slimming agents (for
example, aminophylline and tea extract), analgesic drugs (for
example, indomethacin and dl-camphor), blood circulation promoters
(for example, acidic mucopolysaccharide and chamomile), swelling
improvers (for example, horse chestnut extract and flavone
derivatives), fomentations (for example, aqueous boric acid,
physiological saline, and aqueous alcohols), fat-splitting
components (for example, jujube extract, caffeine, and tonalin),
cosmetics (for example, aloe extracts, vitamin preparations,
hormone preparations, anti-histamines, and amino acids),
antibacterial agents and sterilizers (for example, carbolic acid
derivatives, boric acid, iodine preparations, invert soaps,
salicylic acid based substances, sulfur, and antibiotics), and mold
inhibitors.
[0345] The percutaneously absorptive drug is not particularly
limited so far as it has percutaneous absorption. Examples thereof
include corticosteroids, anti-inflammatory drugs, hypertension
drugs, anesthetics, hypnotic sedatives, tranquilizers,
antibacterial substances, antifungal substances, skin stimulants,
inflammation inhibitors, anti-epileptics, analgesics, antipyretics,
anesthetics, mold inhibitors, antimicrobial antibiotics, vitamins,
antiviral agents, swelling improvers, diuretics, antihypertensives,
coronary vasodilators, anti-tussive expectorants, slimming agents,
anti-histamines, antiarrhythmic agents, cardiotonics,
adrenocortical hormones, blood circulation promoters, local
anesthetics, fat-splitting components, and mixtures thereof.
However, it should not be construed that the invention is limited
thereto. These drugs are used singly or in admixture of two or more
kinds thereof as the need arises.
[0346] The content of such a functional substance is not
particularly limited so far as it falls within the range where the
effect of a medicine can be expected. However, from the viewpoints
of adhesive strength as well as pharmacological effect and economy,
the content of the functional substance is preferably from 0.01 to
25 parts by weight, and more preferably from 0.5 to 15 parts by
weight based on 100 parts by weight of the adhesive.
[0347] Furthermore, a method for providing the adhesive layer is
not limited so far as a thermal packaging body for joint
surroundings can be fixed. The adhesive layer may be entirely
provided or partially or intermittently provided. Examples of its
shape include various shapes such as a network-like shape, a
stripe-like shape, a dot-like shape, and strip-like shape.
[0348] In the sectional exothermic part or the heat generating
composition molded body of the invention, its maximum width is
usually from 0.5 to 60 mm, preferably from 0.5 to 50 mm, more
preferably from 1 to 50 mm, further preferably from 3 to 50 mm,
still further preferably 3 to 30 mm, even further preferably from 5
to 20 mm, even still further preferably from 5 to 15 mm, and most
preferably from 5 to 10 mm. Furthermore, its maximum height is
usually from 0.1 to 30 mm, preferably from 0.1 to 10 mm, more
preferably from 0.3 to 10 mm, further preferably from 1 to 10 mm,
and still further preferably from 2 to 10 mm. Moreover, its longest
length is usually from 5 to 300 mm, preferably from 5 to 200 mm,
more preferably from 5 to 100 mm, further preferably from 20 to 150
mm, and still further preferably from 30 to 100 mm.
[0349] A capacity of the sectional exothermic part or a volume of
the heat generating composition molded body is usually from 0.015
to 500 cm.sup.3, preferably from 0.04 to 30 cm.sup.3, more
preferably from 0.1 to 30 cm.sup.3, further preferably from 1 to 30
cm.sup.3, and still further preferably from 3 to 20 cm.sup.3.
[0350] In the sectional exothermic part, when the sectional
exothermic part which is an accommodating region of the heat
generating composition is filled with the heat generating
composition molded body, a volume ratio of the volume of the heat
generating composition molded body which is an occupying region of
the heat generating composition molded body to the capacity of the
sectional exothermic part which is an accommodating region of the
heat generating composition is usually from 0.6 to 1, preferably
from 0.7 to 1, more preferably from 0.8 to 1, and further
preferably from 0.9 to 1.0.
[0351] Furthermore, a width of the sectioned part which is a space
between the sectional exothermic parts is not limited so far as
sectioning can be achieved. It is usually from 0.1 to 50 mm,
preferably from 0.3 to 50 mm, more preferably from 0.3 to 50 mm,
further preferably from 0.3 to 40 mm, still further preferably from
0.5 to 30 mm, even further preferably from 1.0 to 20 mm, and even
still further preferably from 3 to 10 mm.
[0352] Incidentally, the heat generating composition molded body or
the sectional exothermic part may have any shape. The shape may be
a planar shape, and examples thereof include a circular shape, an
elliptical shape, a polygonal shape, a star shape, and a flower
shape. Also, the shape may be a three-dimensional shape, and
examples thereof include a polygonal pyramidal shape, a conical
shape, a frustum shape, a spherical shape, a parallelepiped shape,
a cylindrical shape, a semi-pillar shape, a semicylindroid shape, a
semicylidrical shape, a pillar shape, and a cylindroid shape.
Furthermore, in these shapes, the corner may be rounded, thereby
processing the corner in a curvilinear or curved state, or the
central part may be provided with a concave.
[0353] Furthermore, the "volume of the heat generating composition
molded body of the invention" as referred to herein means a volume
of the heat generating composition molded body or compressed heat
generating composition molded body.
[0354] Furthermore, the "capacity of the sectional exothermic part"
as referred to herein means an internal capacity of the sectional
exothermic part having a heat generating composition molded body
accommodated therein.
[0355] Further, the shape of the heat generating body is not
limited but can be selected from the group consisting of a
rectangular shape, a circular shape, an elliptical shape, a
polygonal shape, a broad bean-like shape, an eye mask-like shape, a
paper lantern-like shape, a cocoon-like shape, a gourd-like shape,
a rectangular shape with rounded corners, a square shape with
rounded corners, an egg-like shape, a boomerang-like shape, a
comma-shaped bead-like shape, a wing-like shape, a nose-like shape,
a star-like shape, and a foot-like shape.
[0356] Furthermore, the heat generating body or accommodating bag
can be provided with at least one member of characters, designs,
symbols, numerals, patterns, photographs, pictures, and colors in
at least a part thereof.
[0357] The heat generating body of the invention is able to give
various shapes, thicknesses and temperature zones and therefore,
can be used for various utilities such as use for a joint, facial
esthetic use, use for eyes, slimming use, use for heating or
warming a dripping solution, use for a wet compress pack, use for a
medical body warmer, use for a neck, use for a waist, use for a
mask, use for a glove, use for hemorrhage, use for relaxation of
symptoms such as shoulder pain, muscular pain, and menstrual pain,
use for a cushion, use for heating or warming a human body during
the operation, use for a thermal sheet, use for thermally
volatilizing an aroma, use for an abdomen, insecticidal use by
thermal volatilization, and use for treating cancer in addition to
common warming of a human body. In addition, the heat generating
body of the invention can be used for heating or warming machines,
pets, etc.
[0358] For example, in the case of using for relaxation of
symptoms, the heat generating body of the invention is applied
directly in a necessary site of the body or indirectly via a cloth,
etc. Furthermore, in the case of using for heating or warming a
human body during the operation, a method for using the heat
generating body of the invention includes the following
methods.
[0359] (1) The heat generating body is directly applied to a body
requiring heating or warming.
[0360] (2) The heat generating body is fixed on a covering, etc.
and covered on the body.
[0361] (3) The heat generating body is fixed on a cushion to be
placed beneath the body, etc.
[0362] (4) The heat generating body is used as a covering or a
cushion which is a product having the heat generating body provided
therein in advance.
[0363] Incidentally, examples of the pain of muscles or bones
include acute muscle pain, acute bone pain, acute reference pain,
previous muscle pain, previous bone pain, chronic reference pain,
and join pain of knee, elbow, etc.
[0364] The holding time is not limited but is preferably from 20
seconds to 24 hours, more preferably from one hour to 24 hours, and
further preferably from 8 hours to 24 hours.
[0365] The holding temperature is preferably from 30 to 50.degree.
C., more preferably from 32 to 50.degree. C., further preferably
from 32 to 43.degree. C., still further preferably from 32 to
41.degree. C., and even further preferably from 32 to 39.degree.
C.
[0366] The working examples of the invention will be specifically
described below on a basis of the drawings, but it should not be
construed that the invention is limited thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0367] FIG. 1 is a plan view of an embodiment of a heat generating
body of the invention.
[0368] FIG. 2 is a cross-sectional view along the line Z-Z of the
same.
[0369] FIG. 3 is an oblique view to show the production step.
[0370] FIG. 4 is a cross-sectional view of an embodiment of the
temporarily adhered heat generating body.
[0371] FIG. 5 is a plan view of another embodiment of the heat
generating body of the invention.
[0372] FIG. 6 is a plan view of another embodiment of the heat
generating body of the invention.
[0373] FIG. 7(a) is an oblique view of the temporary adhesion
plate; and FIG. 7(b) is an oblique view of a modified example of
the same.
[0374] FIG. 8(a) is an oblique view of an embodiment of the
temporary adhesion roll; and FIG. 8(b) is a side view of the
same.
[0375] FIG. 9(a) is an oblique view of another embodiment of the
temporary adhesion roll; FIG. 9(b) is a cross-sectional view to
show the relationship between the temporary adhesion roll and the
heat generating body; FIG. 9(c) is a cross-sectional view to show
the relationship between the temporary adhesion roll and the heat
generating body; FIG. 9(d) is an oblique view to show a part of the
temporarily adhered heat generating body; and FIG. 9(e) is a
cross-sectional view to show a part of the heat generating body
partially having a sagging.
[0376] FIG. 10 is an oblique view of another embodiment of the
temporary adhesion roll.
[0377] FIG. 11 is a plan view of another embodiment of the
temporary adhesion roll.
[0378] FIG. 12 is a plan view of another embodiment of the
temporary adhesion roll.
[0379] FIG. 13 is a plan view of another embodiment of the
temporary adhesion roll.
[0380] FIG. 14 is a plan view of another embodiment of the
temporary adhesion roll.
[0381] FIG. 15 is a side view of the collapsing plate of an
embodiment of the sectional exothermic part of the heat generating
body.
[0382] FIG. 16 is a side view of an embodiment of the collapsing
roll of the sectional exothermic part of the heat generating
body.
[0383] FIGS. 17(a) and 17(b) are each a cross-sectional view of an
embodiment of a part of the collapse step of the sectional
exothermic part or exothermic part of the heat generating body.
[0384] FIG. 18 is a schematic view of an embodiment of the
production step of the heat generating body.
[0385] FIG. 19 is a schematic view of another embodiment of the
production step of the heat generating body.
[0386] FIG. 20 is a plan view of filter paper for the measurement
of water mobility value in the invention.
[0387] FIG. 21 is an oblique view for explaining the measurement of
water mobility value in the invention.
[0388] FIG. 22 is a side view for explaining the measurement of
water mobility value in the invention.
[0389] FIG. 23 is a cross-sectional view for explaining the
measurement of water mobility value in the invention.
[0390] FIG. 24 is a plan view of a filter paper after carrying out
the measurement of water mobility value in the invention.
DESCRIPTION OF REFERENCE NUMERALS AND SIGNS
[0391] 1: Heat generating body [0392] 1A: Heat generating
composition molded body [0393] 4: Substrate [0394] 5: Covering
material [0395] 6: Sagging [0396] 7: Temporary adhering part [0397]
7B: Space [0398] 8: Heat seal part (including a mixed layer of an
adhesive and a heat sealing agent) [0399] 9: Adhesive layer [0400]
9A: Air-permeable adhesive layer [0401] 11: Sectioned part (seal
part) [0402] 12: Perforation [0403] 13: Separator [0404] 14:
Rotation body type molding device (body of rotation having a cavity
having a desired shape) [0405] 15: Hopper [0406] 17: Temporary
adhesion plate [0407] 17A: Temporary adhering seal part [0408] 17B:
Concave [0409] 18: Temporary adhesion roll [0410] 18A: Temporary
adhering seal part [0411] 18B: Concave [0412] 19: Heat seal roll
[0413] 20: Cut roll [0414] 21: Delivery roll [0415] 21A: Press roll
[0416] 22: Collapsing plate [0417] 22A: Collapsing part [0418] 22B:
Collapsing roll [0419] 22C: Collapsing part [0420] 22D: Collapsing
plate [0421] 23: Belt conveyor [0422] 23A: Belt conveyor [0423] 24:
Melt blow machine [0424] 25: Melt blow machine [0425] 26: Pushing
plate [0426] 27: Flat plate [0427] 28: Non-water absorptive film
(polyethylene film, etc.) [0428] 29: Filter paper in which eight
lines are drawn radiating from the central point with an interval
of 45.degree. [0429] 30: Die plate [0430] 31: Hole [0431] 32:
Sample [0432] 33: Stainless steel plate [0433] 34: Distance to the
oozed-out locus of water or aqueous solution [0434] 35: Position
corresponding to a hollow cylindrical hole on filter paper
(circumferential part)
EXAMPLES
Example 1
[0435] As shown in FIG. 1 which is a plan view and FIG. 2 which is
a cross-sectional view along the line Z-Z of FIG. 1, a heat
generating body 1 of the invention is one in which a heat
generating composition molded body 1A is sealed in a rectangular
flat accommodating bag of 130 mm in length.times.80 mm in width,
and the accommodating bag is made of an air-impermeable substrate 4
and an air-permeable covering material 5. On the exposed surface
side of the substrate 4, a separator 13 made of a polyester-made
release film having a thickness of 38 .mu.m is provided via an
adhesive layer 9 which is made of a non-aromatic polyolefin based
hot melt based adhesive having a basis weight of 150 g/m.sup.2.
[0436] The covering material 5 is made of an extensible
three-layered film having a width of 130 mm. That is, a porous film
having a basis weight of 50 g/m.sup.2 is laminated on a
polyester-made spunlace non-woven fabric having a basis weight of
30 g/m.sup.2 via a hot melt based sticky layer as provided by a
melt blow system. This covering material 5 has a moisture
permeability of 350 g/m.sup.2/24 hr as measured by the Lyssy
method.
[0437] The heat generating body 1 is produced as shown in FIG.
3.
[0438] While drawing out the heat generating body having the
separator 13 provided on a polyethylene film-made substrate 4 via
the adhesive layer 9 in a roll-like form at 30 m/min, the heat
generating composition molded body 1A as molded in dimensions of
110 mm.times.70 mm.times.1.7 mm was transferred at intervals of 20
mm into the central part in the side of the substrate 4 by means of
force-through molding.
[0439] Next, as shown in FIG. 4, while drawing out the covering
material 5 as wound in a roll-like form and applying an olefin
based hot melt based adhesive at 1 g/m.sup.2 onto the whole of the
porous film surface side of the covering material 5 by a melt blow
system, the heat generating composition molded body 1A was covered
thereon such that its hot melt based adhesive layer 6 came into
contact with the substrate 4, and the periphery thereof was contact
bonded to form a temporary adhering part 7. Thereafter, the
surroundings of the heat generating composition molded body 1A were
heat sealed together with the temporary adhering part 8 by using a
heat seal roll and then cut, thereby producing an extra-thin heat
generating body of 8 mm in seal width.times.about 0.94 mm in
thickness.times.130 mm.times.80 mm.
[0440] As a result of the production, seal failure was not
observed.
[0441] Incidentally, each of the cut heat generating bodies 1 is
subsequently sent to a packaging step and sealed in an airtight
outer bag, an aspect of which is, however, not illustrated.
[0442] In this Example, a heat generating composition as prepared
by adding water to 70 parts by weight of an iron powder (particle
size: not more than 300 .mu.m), 10 parts by weight of active carbon
(particle size: not more than 300 .mu.m), 2 parts by weight of
salt, 0.7 parts by weight of a water absorptive polymer (particle
size: not more than 300 .mu.m) and 0.1 parts by weight of calcium
hydroxide so as to have a water mobility value of 8 was used as the
moldable heat generating composition.
[0443] By regulating the water mobility value of the heat
generating composition at 8 in this way, since it is not required
to use a thickener, the exothermic characteristics are not
sacrificed. Furthermore, it becomes easy to achieve lamination in
the central part on the substrate by force-through molding; it is
possible to achieve lamination with high precision in a desired
laminated region; and it becomes possible to make the thickness of
the heat generating composition molded body 1A very thin and
uniformly control it.
[0444] Furthermore, the heat generating composition molded body was
sealed in an outer bag; and after a lapse of 24 hours, the outer
bag was broken, and the heat generating composition molded body was
stuck on the surface of a human body and then provided for usual
use. As a result, the temperature rose to about 38.degree. C.
within about 1 to 2 minutes, and thereafter, the heat generation
was continued at 38 to 41.degree. C. over 9 hours or more. The heat
generating composition molded body did not move at all within the
accommodating body during the use, and uniform heat generation was
found over the entire surface.
Example 2
[0445] FIG. 5 is an example of the heat generating body 1 in which
a sectional exothermic part 1B is provided by 3 lines and 4 rows in
the same manner as in Example 1. A perforation 12 is provided in
the heat seal part 11. Seal failure was not observed.
Example 3
[0446] FIG. 6 is an example of the heat generating body 1 having a
sectional exothermic part 1B as produced by using the same
substrate 4, covering material 5 and heat generating composition as
in Example 1. The heat generating composition molded body 1B as
formed in dimensions of 110 mm.times.70 mm.times.0.5 mm at
intervals of 20 mm in the central part of a substrate 4 by
force-through molding while drawing out the substrate 4 as wound in
a roll-like form in a width of 130 mm at 35 m/min in the horizontal
direction was disposed at intervals of 20 mm by 4 lines and 3 rows.
A covering material as prepared by coating 1 g/m.sup.2 of a hot
melt based adhesive on the porous film surface side by a melt blow
system was covered on the heat generating composition molded body
1B, and the outer periphery of the substrate 4 and the covering
material and the adjacent sectional exothermic parts 1B were
temporarily adhered by adhesion. Thereafter, the resultant was heat
sealed by using three heat seal rolls and cut, thereby producing an
extra-thin heat generating body of about 0.94 mm in
thickness.times.130 mm.times.80 mm. As a result, seal failure was
not observed.
[0447] Furthermore, the heat generating composition molded body was
sealed in an outer bag; and after a lapse of 24 hours, the outer
bag was broken, and the heat generating composition molded body was
stuck on the surface of a human body and then provided for usual
use. As a result, the same results as in Example 1 were
obtained.
Example 4
[0448] A heat generating body of Example 4 is different in the
points that while coating 1 g/m.sup.2 of a hot melt based adhesive
on a substrate and a heat generating composition molded body as
formed in the same manner as in Example 1, a covering material was
covered thereon such that the porous film side came into contact
therewith. Incidentally, as the substrate, the covering material
and the heat generating composition, the same materials as in
Example 1 were used.
[0449] A heat generating composition molded body of 5 mm in
width.times.110 mm in length.times.3 mm in height was disposed by 4
lines and 2 rows (8 in total) at intervals of 7 mm on the
substrate. The covering material was contact bonded in a width of 5
mm between the adjacent heat generating composition molded bodies,
thereby providing a temporary adhering part. Next, the central part
of the temporary adhering part was heat sealed in a width of 1 mm,
and at the same time, the outer surroundings of the substrate and
the covering material were heat sealed in a width of 8 mm, thereby
obtaining a heat generating body having 8 sectional exothermic
parts.
[0450] Next, the sectional exothermic parts were pressurized by
using a planar deadhesion roll, thereby moving a part of the heat
generating composition molded body into a non-heat sealed temporary
adhering part, and the surroundings of the heat generating body was
cut, thereby obtaining a heat generating body having a sectional
exothermic part of 8 mm in seal width of the surroundings and 1 mm
in seal width. Then, the heat generating body was sealed in an
air-impermeable outer bag.
[0451] After sealing the heat generating composition molded body in
an outer bag and then lapsing 24 hours, the outer bag was broken,
and the heat generating composition molded body was stuck on the
surface of a human body and then provided for usual use. As a
result, the temperature rose to about 38.degree. C. within about 1
to 2 minutes, and thereafter, the heat generation was continued at
38 to 41.degree. C. over 10 hours or more. The heat generating
composition molded body did not move at all within the
accommodating body during the use and was flexible as a heat
generating body and well adaptive with the curved surfaces of the
body. Uniform heat generation was found over the entire
surface.
Example 5
[0452] FIG. 18 is a schematic view of the production step of a heat
generating body including a temporary adhering step. A heat
generating composition 2 is charged in a hopper 15 while drawing
out a substrate 4 at 15 m/min from a delivery roll 21. Then, a heat
generating composition molded body of 110 mm.times.70 mm is formed
at intervals of 20 mm in the central part on the substrate 4 on a
belt conveyor 23 from the hopper 15 via a rotation body type
molding device 14. Incidentally, the heat generating composition 2
is attracted by a magnet 37 provided beneath an upper belt of the
belt conveyor 23 so that it is easily placed on the substrate
4.
[0453] In addition, the covering material 5 is covered on the
substrate 4 and the heat generating composition molded body by
temporary adhesion rolls 18 in the MD direction which also
functions as a doubling calender during traveling on the belt
conveyor 23. A hot melt based adhesive is coated on the entire
surface of the covering material 5 in the porous film side by a
melt blow machine 24.
[0454] Next, the periphery of the heat generating composition
molded body was heat sealed in a width of 5 mm, and at the same
time, the outer periphery of the heat generating body was heat
sealed in a width of 8 mm by heat seal rolls 18C.
[0455] Next, the heat generating composition molded body was cut by
using die cut rolls 20, thereby obtaining a heat generating body of
126 mm.times.86 mm. In the resulting heat generating body, heat
seal failure was not observed.
[0456] The cut heat generating body was subsequently sent to a
packaging step and sealed in an airtight outer bag (as not
illustrated). After sealing the heat generating composition molded
body in an outer bag and then lapsing 24 hours, the outer bag was
broken, and the heat generating composition molded body was stuck
on the surface of a human body and then provided for use. As a
result, the same results as in Example 1 were obtained. In this
Example, a measure for providing an air-permeable adhesive layer is
not particularly limited so far as an air-permeable adhesive layer
can be formed. A melt blow method, a curtain rail method, and the
like can be employed.
[0457] Furthermore, a heat generating composition consisting of 70
parts by weight of an iron powder (particle size: not more than
300.mu.), 7 parts by weight of active carbon (particle size: not
more than 300.mu.), 2 parts by weight of salt, 0.7 parts by weight
of a water absorptive polymer, 3.0 parts by weight of a wood meal,
1.0 part by weight of sodium sulfite, 0.1 parts by weight of
calcium hydroxide, and 37 parts by weight of water was used as the
heat generating composition of this Example.
[0458] In FIG. 19, a step for reinforcing the heat seal step as
shown in FIG. 18 and providing a separator-provided air-permeable
adhesive layer is established. In the established step, the heat
generating composition molded body other than an air-permeable
adhesive layer 9A as coated with a hot melt adhesive on a
silicone-treated polyester-made separator 13 by a melt blow system
was laminated on a covering material 5 and cut by die cut rolls
20.
Example 6
[0459] In this Example, a heat generating body was produced in the
same manner as in Example 5.
[0460] As the heat generating composition of this Example, a
reaction mixture consisting of 100 parts by weight of an iron
powder (particle size: not more than 300 .mu.m), 6.5 parts by
weight of active carbon (particle size: not more than 300 .mu.m),
2.3 parts by weight of a wood meal (particle size: not more than
150 .mu.m), 2.3 parts by weight of a water absorptive polymer
(particle size: not more than 300 .mu.m), 0.5 parts by weight of
calcium hydroxide, 0.7 parts by weight of sodium sulfite and 10
parts by weight of 6% salt water and having a water mobility value
of less than 0.01 was charged in a stirring type batch wise
oxidizing gas contact treatment device. In the state that the upper
portion of the oxidizing gas contact treatment device was opened to
air, the reaction mixture was stirred under circumstances at
20.degree. C. After 120 seconds, at the point of time when a
temperature rise of the reaction mixture reached 45.degree. C., the
reaction mixture was sealed in an air-impermeable accommodating bag
and cooled to room temperature to obtain a heat generating mixture
of the invention. Next, 6% salt water was added and mixed in the
heat generating mixture, thereby obtaining a heat generating
composition having a water mobility value of 10, which was then
used as the heat generating composition of the invention.
* * * * *