U.S. patent application number 10/468824 was filed with the patent office on 2004-04-22 for laminate for packaging and package.
Invention is credited to Kurahashi, Akihiko, Mitsuzuka, Hiroyuki, Nakagami, Hiroyuki.
Application Number | 20040077248 10/468824 |
Document ID | / |
Family ID | 18910249 |
Filed Date | 2004-04-22 |
United States Patent
Application |
20040077248 |
Kind Code |
A1 |
Kurahashi, Akihiko ; et
al. |
April 22, 2004 |
Laminate for packaging and package
Abstract
A packaging multilayer material 14 is formed by sequentially
laying an air permeable heat-resistant fiber material layer 11
having a heat-resistance of not lower than 150.degree. C., a
polyethylene type resin spunbonded non-woven fabric layer 12 and a
microporous film layer 13 in the above listed order by means of
thermal bonding. The air permeable heat-resistant fiber material
layer 11 is made of resin spunbonded non-woven fabric having a
melting point between 150 and 300.degree. C. and the polyethylene
type resin spunbonded non-woven fabric layer 12 is an
ethylene-.alpha.-olefin copolymer having a density between 880 and
950 kg/m.sup.3, while the microporous film layer 13 is made of
polyethylene type resin.
Inventors: |
Kurahashi, Akihiko; (Chiba,
JP) ; Nakagami, Hiroyuki; (Tokyo, JP) ;
Mitsuzuka, Hiroyuki; (Chiba, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
18910249 |
Appl. No.: |
10/468824 |
Filed: |
August 25, 2003 |
PCT Filed: |
December 14, 2001 |
PCT NO: |
PCT/JP01/10979 |
Current U.S.
Class: |
442/401 |
Current CPC
Class: |
B32B 2262/0253 20130101;
B65D 81/267 20130101; B65D 81/28 20130101; B32B 5/26 20130101; B32B
27/12 20130101; B65D 81/18 20130101; B32B 27/02 20130101; Y10T
442/681 20150401; B32B 2307/724 20130101; B32B 27/32 20130101; B32B
5/022 20130101 |
Class at
Publication: |
442/401 |
International
Class: |
D04H 003/16 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2001 |
JP |
2001-049093 |
Claims
1. A packaging multilayer material formed by sequentially laying an
air permeable heat-resistant fiber material layer having a
heat-resistance of not lower than 150.degree. C., a polyethylene
type resin spunbonded non-woven fabric layer and a micro-porous
film layer in the above listed order by means of thermal
bonding.
2. The packaging multilayer material according to claim 1, wherein
the air permeable heat-resistant fiber material layer is made of
resin spunbonded non-woven fabric having a melting point between
150 and 300.degree. C.
3. The packaging multilayer material according to claim 1 or 2,
wherein the polyethylene type resin is an ethylene-.alpha.-olefin
copolymer having a density between 880 and 950 kg/m.sup.3.
4. The packaging multilayer material according to any of claims 1
through 3, wherein the microporous film layer is made of
polyethylene type resin.
5. A packaging multilayer material formed by laminating an air
permeable heat-resistant fiber material layer having a
heat-resistance of not lower than 150.degree. C., a polyethylene
type resin spunbonded non-woven fabric layer, a micro-porous film
layer and an air permeable material in the above listed order by
means of thermal bonding.
6. The packaging multilayer material according to claim 5, wherein
the air permeable material is non-woven fabric.
7. The packaging multilayer material according to claim 6, wherein
the non-woven fabric is spunbonded non-woven fabric or split fiber
non-woven fabric.
8. The packaging multilayer material according to any of claims 5
through 7, wherein the air permeable heat-resistant fiber material
layer is made of resin spunbonded non-woven fabric having a melting
point between 150 and 300.degree. C.
9. The packaging multilayer material according to claim 4 or 5,
wherein the polyethylene type resin is an ethylene-.alpha.-olefin
copolymer having a density between 880 and 950 kg/m.sup.3.
10. The packaging multilayer material according to any of claims 1
through 8, wherein the microporous film layer is made of
polyethylene type resin.
11. A packaging multilayer material formed by sequentially laying
an air permeable heat-resistant fiber material layer having a
heat-resistance of not lower than 150.degree. C., a polyethylene
type resin spunbonded non-woven fabric layer and a paper layer in
the above listed order by means of thermal bonding.
12. A packaging multilayer material formed by sequentially laying a
polyethylene type resin spunbonded non-woven fabric layer and a
paper layer in the above listed order by means of thermal
bonding.
13. The packaging multilayer material according to claim 11 or 12,
wherein the air permeable heat-resistant fiber material layer is
made of resin spunbonded non-woven fabric having a melting point
between 150 and 300.degree. C.
14. The packaging multilayer material according to any of claims 11
through 13, wherein the polyethylene type resin is an
ethylene-.alpha.-olefin copolymer having a density between 880 and
950 kg/m.sup.3.
15. A package formed by using a packaging multilayer material
according to any of claims 1 through 14.
16. A package formed by using a packaging multilayer material
according to any of claims 1 through 14 and containing a
deoxidizing agent, a drying agent, a moisture absorbing agent, a
deodorant a heat generating agent, an insecticide, a desiccating
agent or an aromatic agent.
Description
TECHNICAL FIELD
[0001] This invention relates to a packaging multilayer material
and also to a package formed by using such a multilayer material.
More particularly, the present invention relates to a packaging
multilayer material for packaging a functional article such as a
deoxidizing agent, a drying agent or a desiccating agent and also
to a package formed by using such a multilayer material.
BACKGROUND ART
[0002] Many deoxidizing agents and drying agents have been used in
recent years in order to prevent decay, degeneration and
degradation of processed foods. Deoxidizing agents (oxygen
absorbing agents) are used in a powdery or granular state and
contained in air permeable small bags. Biscuits including rice
crackers and dried layer that can lose their tastes and commercial
values by absorbing moisture are also packaged with silica gel or
some other drying agent contained in a bag.
[0003] Thus, such packages of functional agents are normally
packaged by means of an air permeable packaging material in order
to absorb air, moisture, oxygen and so on in the packages (bags)
containing such articles. Air permeable packaging materials are
also used for deodorants and insecticides so that effective
ingredients may come out from packaged agents as they permeate
through the packaging material. In recent years, odor adsorbents
including powdery active carbon and charcoal are packaged in the
form of sheets having a large surface area and often used on beds
in hospitals. Additionally, as a result of expanded trades of
electro/electric devices, medical devices, precision machines and
so on, large packages of drying agents and moisture absorbing
agents are being widely used to protect them against moisture and
prevent oxidization.
[0004] Air permeable packaging materials are required to prevent
the packaged powdery agents from leaking and show a sufficient
heat-sealing strength when forming packages. In other words, they
are required to have a good bulking/packaging property and show a
high and stable sealing strength so as to be adapt themselves to
continuous high speed packaging operations. Additionally, if a
deliquescent desiccating agent is contained, the packaging material
is also required to be waterproof. Particularly, there is a strong
demand for packaging materials that can be applied equally to small
packages of deoxidizing agents and desiccating agents and to large
packages of active carbon and charcoal and, at the same time, have
appropriate waterproof, moisture permeating and air permeating
properties.
[0005] The following prior art air permeable packaging materials
that can be used for packaging any of the above listed agents are
known.
[0006] (1) Japanese Patent Publication No. 293667
[0007] This published Japanese patent descloses a composite sheet
having a paper layer and a non-woven fabric layer that is made of
skin-core type bicomonent fibers, of which the non-woven fabric
includes a skin component having a melting point not higher than
160.degree. C. and a core component having a melting point higher
than that of the skin component by 30.degree. C. or more. In the
composite sheet, the skin component of the non-woven fabric is
thermally bonded to the paper to show an interlayer bonding
strength of not lower than 400 g/15 mm width.
[0008] However, since the composite sheet is formed by using
non-woven fabric made of skin-core type bicomponent fibers, it has
a problem that non-woven fabric cannot be manufactured on a stable
basis because of the difference of viscosity between and the
compatibility of the molten resin of the skin and that of the core.
Additionally, the sealing effect is not satisfactory and it can be
difficult to raise the packaging rate. Furthermore, the low melting
point resin for forming the skin component of the bicomonent fibers
dominates the operation of forming the multilayer and the
heat-sealing operation. Therefore, the temperature-related
conditions face limitations at the time of lamination and the
sealing effect also faces limitations at the time of
heat-sealing.
[0009] (2) Japanese Patent Application Laid-Open Publication No.
10-235817
[0010] This patent document discloses a packaging material to be
used for plate-shaped pieces of an oxygen absorbing agent and the
packaging material is formed by using warifu (split fiber non-woven
fabric) made of polyethylene resin for the inner layer, water
absorbing paper for the intermediate layer and a paper board for
the outer layer. However, the process of manufacturing the
packaging material is complex because, for one reason, it requires
a step of forming a large number of fine pores having a diameter of
about 0.5 mm through warifu in order to make the packaging material
air permeable. Additionally, the warifu layer and the paper layer
adhere to each other only poorly so that the packaging material in
fact requires sandwich lamination, using polyethylene resin, as
described in the examples of the patent document. For these
reasons, there may be a problem of difficulty of controlling the
moisture permeability and the air permeability of the material.
[0011] As air permeable materials, micro-porous film layers
obtained by extending polyethylene film containing an inorganic
bulking agent are known. However, since the micro-porous film
layers do not have a sufficient strength, it is known that they are
mostly used as a material for forming multilayer materials with
non-woven fabric.
[0012] (3) Japanese Patent Publication No. 2736773
[0013] This published Japanese patent discloses a method of
manufacturing a sheet-shaped material to be used for forming a
windproof laminate that is prepared by bonding a sheet of air
permeable filament spunbonded non-woven fabric with a mass per unit
area of 30 to 100 g/m.sup.2 that carries adhesive applied thereto
to a micro-porous film layer as described above with a non-contact
area left unbonded, the sheet-shaped material being adapted to be
used in a process of making the outer wall of a wooden house air
permeable.
[0014] (4) Japanese Patent Application Laid-Open Publication No.
4348931
[0015] This patent document discloses a multilayer article formed
by bonding a micro-porous film layer as described above having an
air permeability of 5,000 seconds/100 cc or less and a thickness of
35 to 100 .mu.m to nylon or polyester type non-woven fabric with a
mass per unit area of 20 to 50 g/m.sup.2 by spot bonding with an
adhesive carrying area of 10 to 30%. It also describes applications
of such a multilayer article including umbrellas.
[0016] (5) Japanese Patent Application Laid-Open Publication No.
11-972
[0017] This patent document discloses a multilayer article obtained
by using polyolefin type non-woven fabric with a mass per unit area
of 5 to 20 g/m.sup.2, an average fiber diameter of 0.2 to 2 deniers
and a bulk specific gravity of 0.05 or less.
[0018] (6) Japanese Patent Application Laid-Open Publication No.
11-99601
[0019] This patent document discloses a composite film whose bonded
state realized by using a hot-melt adhesive agent is expressed by a
numerical value. It also describes applications of such a composite
film including back sheets of paper nappies and sanitary
napkins.
[0020] All the above described multilayer materials employ an
adhesive agent in a form or another and are therefore accompanied
by a number of problems including a problem of a complex
manufacturing process, environment-related problems, a problem of
the smell of the adhesive agent and that of reduction or
fluctuations of the air permeability and the moisture permeability.
The following multilayer articles are proposed to avoid the above
listed problems.
[0021] (7) Japanese Patent Application Laid-Open Publication No.
6-316022
[0022] This patent document discloses a multilayer article of
polyolefin type micro-porous film, polyolefin type non-woven fabric
and polyolefin split fiber non-woven fabric that are integrally
formed by thermal bonding.
[0023] (8) Japanese Patent Application Laid-Open Publication No.
9-76386
[0024] This patent document discloses a moisture permeable
multilayer sheet formed by laying micro-porous polyolefin moisture
permeable resin film and non-woven fabric one on the other by means
of partial thermal bonding as well as wears and moisture absorbing
articles prepared by using such a multilayer sheet.
[0025] Moisture absorbing articles such as wears and disposable
nappies obtained by way of a secondary process using a multilayer
sheet prepared by thermal bonding as described above are not
accompanied by serious problems in terms of heat-sealing effect and
heat-sealing strength.
[0026] More particularly, known multilayer materials obtained by
using micro-porous polyolefin type resin film are intended to
improve the strength and the heat-sealing effect of micro-porous
polyolefin type resin film by means of lamination using non-woven
fabric. Therefore, if an adhesive agent or a technique of thermal
bonding is used as means for lamination, it does not give rise to
any serious problem when air permeability and adhesion are secured
to a satisfactory level.
[0027] However, when micro-porous polyolefin type resin film is
used for packaging a functional agent such as a deoxidizing agent
or a drying agent in place of paper, the sealing effect and the
sealing strength of the packaging material are very important
beside the effect of preventing fine powder from leaking. This is
because packages of such a functional agent are packaged with food
mainly for the purpose of preventing the food from being oxidized
and absorbing moisture. Thus, the safety of the food is threatened
when the deoxidizing agent or the drying agent contacts the food.
Therefore, the packaging material needs to be reliably heat-sealed
on a stable basis so that the deoxidizing agent or the drying agent
may not leak out.
[0028] Such reliable heat-sealing and efficient packaging of a
package are strongly desired. However, there are cases where known
two-layered multilayer materials cannot satisfactorily meet such
requirements.
[0029] Therefore, it is a major object of the present invention to
provide a packaging multilayer material that is waterproof,
moisture permeable and appropriately air permeable and can be
manufactured with ease, while having no problems such as a problem
of reduced air permeability due to the adhesive used there and that
of smell but having an excellent strength and providing advantages
including an effect of preventing the packaged article from
leaking, a good sealing effect when packaging an functional article
such as a deoxidizing agent or a moisture absorbing agent, a high
productivity and an adaptability to high speed continuous packaging
operations and also a package formed by using such a laminate
material.
[0030] Known air permeable packaging materials further include the
following.
[0031] (9) Mixed Paper Mainly Made of Pulp and Thermally Bonded
Fiber (High Density Polyethylene/Polypropylene)
[0032] Such mixed paper does not show any difference of melting
point between the front surface and the rear surface of the
material and gives rise to a problem of contaminating the
heat-sealing bar (die roll) during automatic packaging and that of
a reduced printing effect of the front surface.
[0033] (10) Laminate Materials of Paper and Microporous Sealant
Film
[0034] Such a laminate material does not give rise to any serious
problem in terms of sealing strength but it is difficult to obtain
a laminate, while maintaining the air permeability of paper.
[0035] Meanwhile, multilayer materials realized by using paper and
non-woven fabric are also known. However, such materials are formed
by laying resin film as outer layer or by laying paper and
non-woven fabric realized by using extruded film of polyethylene
type resin one on the other in order to provide necessary
waterproof and sealing properties. Therefore, such materials are
different from an air permeable packaging multilayer material
according to the invention in terms of applications and
composition.
[0036] Another object of the present invention is to provide a
packaging multilayer material whose air permeability can be
selectively realized and that is waterproof, moisture permeable and
appropriately air permeable and can be manufactured with ease,
while having no problems such as a problem of reduced air
permeability due to the adhesive used there and that of smell but
having an excellent strength and providing advantages including an
effect of preventing the packaged article from leaking, a good
sealing effect (in terms of sealing strength or adaptability to hot
tucking in particular) when packaging an functional article such as
a deoxidizing agent or a moisture absorbing agent, a high
productivity and an adaptability to high speed continuous packaging
operations and also a package formed by using such a multilayer
material.
DISCLOSURE OF THE INVENTION
[0037] The inventors of the present invention intensively looked
into the heat-sealing effect required to packages (bags) that show
the moisture permeability, the air permeability and the waterproof
effect of microporous film. As a result, the inventors found that a
three-layered multilayer material having a layer of polyethylene
type spunbonded non-woven fabric sandwiched between a micro-porous
film layer and an air permeable heat-resistant fiber material layer
can be formed with ease by thermal bonding and shows an excellent
heat-sealing strength in a heat-sealing operation for forming a
package. Such a laminate material is adapted to high speed
continuous packaging operations to provide a high productivity and
particularly suited for packaging various functional agents and
deliquescent components that are used for packaging food items. The
present invention is based on the above finding. The inventors also
found that a material prepared by laying an air permeable material
on the above described three-layered laminate material by means of
thermal lamination shows an improved heat-sealing strength.
[0038] In an aspect, the present invention is defined as
follows.
[0039] A packaging multilayer material according to the invention
is characterized by sequentially laying an air permeable
heat-resistant fiber material layer having a heat-resistance of not
lower than 150.degree. C., a polyethylene type resin spunbonded
non-woven layer and a micro-porous film layer in the above listed
order by means of thermal bonding.
[0040] For the purpose of the invention, preferably, the air
permeable heat-resistant fiber material layer is made of resin
spunbonded non-woven fabric having a melting point between 150 and
300.degree. C.
[0041] For the purpose of the invention, preferably, the
polyethylene type resin is an ethylene-.alpha.-olefin copolymer
having a density between 880 and 950 kg/m.sup.3.
[0042] For the purpose of the invention, preferably, the
micro-porous film layer is made of polyethylene type resin.
[0043] A packaging multilayer material according to the invention
is characterized by laminating an air permeable heat-resistant
fiber material layer having a heat-resistance of not lower than
150.degree. C., a polyethylene type resin spunbonded non-woven
fabric layer, a micro-porous film layer and an air permeable
material in the above listed order by means of thermal bonding.
[0044] For the purpose of the invention, preferably the air
permeable material is non-woven fabric.
[0045] For the purpose of the invention, preferably, the non-woven
fabric is spunbonded non-woven fabric or split fiber non-woven
fabric.
[0046] For the purpose of the invention, preferably, the air
permeable heat-resistant fiber material layer is made of resin
spunbonded non-woven fabric having a melting point between 150 and
300.degree. C.
[0047] For the purpose of the invention, preferably, the
polyethylene type resin is an ethylene-.alpha.-olefin copolymer
having a density between 880 and 950 kg/m.sup.3.
[0048] For the purpose of the invention, preferably, the
micro-porous film layer is made of polyethylene type resin.
[0049] The inventors of the present invention intensively looked
into the heat-sealing effect and the hot tuck effect required to
packages (bags) that also provide the advantages of paper including
air permeability and printability at the same time. As a result,
the inventors found that a multilayer material adapted to packaging
can be easily obtained by thermal bonding when paper is used for
the surface layer and a specific non-woven fabric is used for the
seal layer. Such a multilayer material provides advantages
including an excellent seating strength, a high hot tuck effect and
adaptability to high speed continuous packaging operations.
Additionally, such a laminate material shows a further improved
heat-sealing effect when a heat-resistant fiber material layer is
formed on the non-woven fabric side to make it possible to package
a large and heavy article.
[0050] Thus, in another aspect, the present invention is defined as
follows.
[0051] A packaging multilayer material according to the invention
is characterized by sequentially laying an air permeable
heat-resistant fiber material layer having a heat-resistance of not
lower than 150.degree. C., a polyethylene type resin spunbonded
non-woven fabric layer and a paper layer in the above listed order
by means of thermal bonding.
[0052] For the purpose of the invention, preferably, the
polyethylene type resin spunbonded non-woven fabric layer and the
paper layer are sequentially laid one on the other in the above
listed order by means of thermal bonding.
[0053] For the purpose of the invention, preferably the air
permeable heat-resistant fiber material layer is made of resin
spunbonded non-woven fabric having a melting point between 150 and
300.degree. C.
[0054] For the purpose of the invention, preferably, the
polyethylene type resin is an ethylene-.alpha.-olefin copolymer
having a density between 880 and 950 kg/m.sup.3.
[0055] In still another aspect of the invention, there is provided
a package using a packaging multilayer material according to the
invention and containing a deoxidizing agent, a drying agent, a
moisture absorbing agent, a deodorant, a heat generating agent, an
insecticide, a desiccating agent or an aromatic agent.
[0056] While known raw materials and manufacturing methods may
appropriately be used to realize a packaging multilayer material
according to the invention, specific raw materials and
manufacturing methods that can be used for the purpose of the
invention will be described below in detail.
[0057] [Air Permeable Heat-Resistant Fiber Material Layer Having
Heat-Resistance not Lower Than 150.degree. C.]
[0058] For the purpose of the invention, fiber made of
thermoplastic resin is generally used for the air permeable
heat-resistant fiber material layer having a heat-resistance of not
lower than 150.degree. C. Fibers that can be used for the air
permeable heat-resistant fiber material layer include
polypropylenes such as homopolymers of propylene and random
copolymers of propylene and a monomer such as ethylene or butene-1
that is contained by 5 mass % or less, polyester fibers prepared
from homopolyesters such as polyethyleneterephthalate,
polybutyleneterephthala- te or polytimethyleneterephthalate,
copolyesters obtained by copolymerization using such a polymer as
main ingredient along with other ingredients and mixed polyesters
that are mixtures of such polyesters and polyamide fibers such as
nylon 6 (polycaprolactamide), nylon 6,6
(polyhexamethyleneadipoamide), nylone 6,10
(polyhexamethylenesebacamide), nylon 11 (polyundecanamide), nylon 7
(poly-.omega.-aminoheptanoic acid), nylon 9
(poly-.omega.-aminononanoic acid) and nylon 12
(polylauricamide).
[0059] Fiber materials other than thermoplastic resin fibers
include those that are not molten such as wooden pulp, paper
mulberry, paper birch and rayon fibers.
[0060] The air permeable heat-resistant fiber material layer is
made of any of such heat-resistant fiber materials that include
woven fabrics, non-woven fabrics, knit fabrics and paper without
limitations. However, spunbonded non-woven fabric made of
thermoplastic resin is preferably used from the viewpoint of
strength, expandability, flexibility and low cost.
[0061] The filament diameter of the spunbonded non-woven fabric
that is used for the air permeable heat-resistant fiber material
layer is not subject to any limitations. Normally, it is between 5
and 60 .mu.m, preferably between 10 and 40 .mu.m. The mass per unit
area of the spunbonded non-woven fabric that is used for the air
permeable heat-resistant fiber material layer is normally between
10 and 100 g/m.sup.2, preferably between 15 and 80 g/m.sup.2. The
effect of preventing edges from being cut is not sufficient during
the heat-sealing operation if the mass per unit area is less than
10 g/m.sup.2, whereas the productivity of the process of forming
the multilayer material by thermal lamination is undesirably
reduced if the mass per unit area is more than 100 g/m.sup.2. More
specifically, in the process of forming the multilayer material,
the polyethylene type resin spunbonded non-woven fabric layer is
molten and penetrates into the heat-resistant fiber material layer
and thermally bonded to the micro-porous film layer to form a
multilayer structure. Thus, the material of the heat-resistant
fiber material layer is selected by taking the required sealing
strength and the productivity of the multilayer structure forming
process into consideration.
[0062] Any known technique may be used for manufacturing spunbonded
non-woven fabric that is used for the air permeable heat-resistant
fiber material layer. For example, firstly the resin material for
forming the spunbonded non-woven fabric is molten, extruded by
means of an extruder and spun out from a spinneret. Then, the spun
fiber is taken up by an air flow traction device such as air sucker
and, if necessary, subjected to an opening step before it is caught
by a web capturing device such as a net conveyor and, if necessary,
the filaments of the fiber are partially bonded by using a heating
means such as hot air or a heated roll.
[0063] Another non-woven fabric layer may be laid on the spunbonded
non-woven fabric on an in-line basis.
[0064] [Polyethylene Type Spunbonded Non-Woven Fabric Layer]
[0065] For the purpose of the invention, the polyethylene type
spunbonded non-woven fabric layer is not subject to any particular
limitations. Materials that can be used for the polyethylene type
spunbonded non-woven fabric layer include monopolymers of ethylene,
copolymers of ethylene and a copolymerizing monomer such as
.alpha.-olefin, unsaturated carbonic acid or a derivative thereof,
or a cyclic olefin and low density polyethylene branched by means
of a high pressure method. Particularly, copolymers (LLDPE) of
ethylene and an .alpha.-olefin having three to ten carbon atoms
such as propylene, butene-1,4-methyl-pentene-1, hexene-1 or
octene-1 may preferably be used. Such polyethylene type resins may
be prepared by using (co)polymers obtained by polymerization using
a Ziegler catalyst, or (co)polymers obtained by polymerization
using a metatllocene type catalyst.
[0066] Particularly, ethylene-.alpha.-olefin copolymers having a
density preferably between 880 and 960 kg/m.sup.3, more preferably
between 900 and 950 kg/m.sup.3, a melting point between 80 and
140.degree. C., preferably between 90 and 130.degree. C., and a
melt flow rate (MFR) between 5 and 60 g/10 min, preferably between
10 and 50 g/10 min, may preferably be used from the viewpoint of
spinning effect, melting point, strength and so on.
[0067] The polyethylene type resin spunbonded non-woven fabric
layer has a filament diameter normally between 50 and 60 .mu.m,
preferably between 10 and 40 .mu.m, and a mass per unit area
between 10 and 200 g/m.sup.2, preferably between 15 and 150
g/m.sup.2, more preferably between 20 and 100 g/m.sup.2.
[0068] The above described process of manufacturing spunbonded
non-woven fabric to be used for the air permeable heat-resistant
fiber material layer can also be used for manufacturing spunbonded
non-woven fabric to be used for the polyethylene type spunbonded
non-woven fabric layer.
[0069] [Micro-porous Film Layer]
[0070] For the purpose of the invention, the micro-porous film
layer is not subject to any particular limitations. Any known
manufacturing process may be used for it so long as it is an
ordinary polyolefin type resin micro-porous film layer, a
polyethylene type resin micro-porous film layer in particular. For
example, a polyolefin type resin micro-porous film layer can be
prepared by bringing in film of polyolefin type resin that contains
organic or inorganic bulking agent or a plasticizing agent and
eluting the bulking agent or the plasticizing agent by means of
solvent or by drawing film of polyolefin type resin containing an
inorganic or organic bulking agent at least in an axial
direction.
[0071] Above all, film obtained by drawing film of polyolefin type
resin containing an inorganic or organic bulking agent at least in
an axial direction is preferably used for the purpose of the
invention. Polyolefin type resin materials that can be used for the
purpose of the invention include copolymers of high density
polyethylene, medium density polyethylene, ethylene-.alpha.-olefin
copolymer, low density polyethylene branched by means of a high
pressure method, polypropylene or propylene and other olefin and
mixtures of such polyolefin compounds, of which a polyethylene type
resin may preferably by used.
[0072] The density of the polyethylene type resin of the
micro-porous film layer is normally between 880 and 960 kg/m.sup.3,
preferably between 900 and 950 kg/m.sup.3, and the melt flow rate
(MFR) thereof [as observed by a method conforming to JIS K7210,
measuring temperature: 190.degree. C., measuring load: 21.18N] is
normally between 0.01 and 10 g/10 min, preferably between 0.02 and
5 g/10 min.
[0073] An organic or inorganic bulling agent is used for the
bulking agent that is contained in the polyolefin type resin.
Examples of bulking agents that can be used for the purpose of the
invention include inorganic bulking agents such as calcium
carbonate, talc, clay, kaolin, silica, diatom earth, magnesium
carbonate, barium carbonate, barium sulfate, calcium sulfate,
calcium sulfite, calcium hydroxide, magnesium hydroxide, aluminum
hydroxide, zinc oxide, calcium oxide, magnesium oxide, titanium
oxide, mica, alumina, zeolite and glass powder and organic bulking
agent such as wood powder, cellulose powder, high melting point
resin powder and bridged resin powder.
[0074] The average grain diameter of the bulking agent is normally
not more than 30 .mu.m, preferably between 0.2 and 10 .mu.m. The
dispersibility and the moldability are degraded when the grain
diameter is too small, whereas the concentration of micropores of
the drawn film is reduced to possibly lower the resistance against
leak of powder. The polyolefin type resin may be made to contain
more than one bulking agents. The bulking agent may be
surface-treated with fatty acid or metal salt of fatty acid in
order to improve the dispersibility of the agent into the
polyolefin type resin and the drawability of the film.
[0075] The content of the inorganic bulking agent is between 20 and
400 mass portions, preferably between 40 and 300 mass portions,
relative to 100 mass portions of the polyolefin type resin.
Micropores are not formed satisfactorily and a sufficient moisture
permeability is not secured when the film is drawn if the content
of the bulking agent is lower than 20 mass %, whereas the mulling
performance of the mixture, the dispersibility, the effect of
forming film and the strength are reduced if the content of the
bulking agent exceeds 400 mass portions.
[0076] If necessary, other resin, elastomer and/or one or more than
one additives that are commonly used with polyolefin type resin
containing a bulking agent may be added to the polyolefin type
resin. Examples of such substances include ethylene-propylene
copolymeric elastomers, liquid or solid hydrocarbon resins,
active-hydrogen-containing liquid polybutadiene, plasticizers,
radical generating agents, thermal stabilizers, ultraviolet
absorbing agents, smoothing agents such as higher fatty acids,
esters thereof, amides thereof and metal salts thereof, coloring
agents and flame retardants.
[0077] Polyolefin type resin is pelletized with a bulking agent
that is added at a pre-determined rate along with various additives
by means of a Banbury mixer, a mulling extrusion molding machine or
the like. Film is formed from the pellets by means of a T-die
extrusion molding machine, an inflation molding machine or the
like. The produced film is then drawn at least along an axis
thereof so as to show a length about 1.5 to 10 times greater than
the original value. The drawing operation may be conducted in a
plurality of steps. The film may be biaxially drawn.
[0078] The operation of drawing polyolefin type resin is conducted
in a temperature range between a level lower than the melting point
thereof by 100.degree. C. and a level lower than the melting point
thereof by 20.degree. C. The strength of the film is improved and
micro-pores are formed in the film as a result of the drawing
operation. The dimensional accuracy of the film can be improved as
a result of the heat treatment of the drawn film. Further,
multilayer surface of the film may be surface-treat with corona
treatment or flame treatment in order to improve the
adhesiveness.
[0079] The thickness of the obtained polyolefin type resin
microporous film layer is between 10 and 200 .mu.m, preferably
between 15 and 100 .mu.m. The moisture permeability of the film is
normally not less than 100 g/m.sup.2.multidot.24 hours, preferably
not less than 500 g/m.sup.2.multidot.24 hours. The gauging method
will be described hereinafter. For the polyolefin type resin
micro-porous film layer to meet the above requirements, it
preferably has micro-pores with an average diameter between 0.1 and
50 .mu.m and shows a percentage of void between 10 and 80%.
[0080] The thickness and the moisture permeability of the
polyolefin type resin micro-porous film layer can be determined
depending on the article to be packaged by the multilayer material
according to the invention and the application of the article so
long as the film layer meets the above requirements.
[0081] Such a polyolefin type resin microporous film layer itself
is known and various such films are commercially available. For
example, moisture permeable drawn polyethylene film containing an
inorganic bulking agent is marketed by Tokuyama Corporation with
the tradename of "PORUM PU35", by Nitto Denko Corporation with the
tradename of "BREATH-RON" and also by Mitsui Chemicals Co., Ltd.
with the tradename of "Espoir".
[0082] [Air Permeable Material]
[0083] For the purpose of the invention, the air permeable material
is selected from air permeable materials that can be thermally
laminated with micro-porous film and have strength sufficient for
operating as protection layer of the micro-porous film in order to
prevent edges from being cut during the heat-sealing operation.
[0084] The air permeability of the air permeable material is not
higher than 100 sec/100 cc, preferably not higher than 10 sec/100
cc as gauged by a method conforming to JIS L 1096. The moisture
permeability of the material falls remarkably when the air
permeability exceeds 100 sec/100 cc so that it may not
satisfactorily absorb moisture and hence no longer operate as
moisture removing agent.
[0085] Non-woven fabric is typically used for the air permeable
material. The method for manufacturing the air permeable material
may be selected from known methods including the spun-bonding
method, the spun-lacing method, the hot air carding method and the
thermal embossing method, of which the spun-bonding method may
preferably be used for the purpose of the invention from the
viewpoint of strength and cost. The mass per unit area is between
10 and 100 g/m.sup.2, preferably between 15 and 70 g/m.sup.2, from
the viewpoint of strength and cost.
[0086] If non-woven fabric is used, the air permeable material
layer may be a single layer or a multilayer. A multilayer non-woven
fabric of high melting point resin non-woven fabric layer/low
melting point resin non-woven fabric layer may preferably be used
for the purpose of the invention in view of the thermal laminate
manufacturing process.
[0087] The material of the non-woven fabric may be selected from
known resin materials including PP, polyolefin materials such as
PE, polyamide materials such as NY and polyester materials such as
PET. When multilayer non-woven fabric is used, a combination of PET
non-woven fabric/PE non-woven fabric may be preferable from the
viewpoint of differentiating the melting points of the layers.
[0088] Non-woven fabrics that can be used for the purpose of the
invention may comprise a core made of polyethyleneterphthalate or
polybutyleneterephthalate that is coated with polyolefin resin.
[0089] Examples of air permeable materials that can be used for the
purpose of the invention include warifus. Warifus non-woven fabrics
that are formed by splitting drawn film of polyolefin resin to
produce split fibers (flat yarns), laying split fibers
longitudinally and transversally and thermally bonding them or
hot-melt bonding them.
[0090] The mass per unit area of warifu is between 10 and 100
g/m.sup.2, preferably between 12 and 40 g/m.sup.2, from the
viewpoint of strength and cost.
[0091] From the viewpoint of adaptability to manufacture of thermal
laminates, multilayer type drawn film of low melting point resin
layer/high melting point resin layer/low melting point resin layer
is preferably used for the purpose of the invention.
[0092] The use of low density polyethylene/high density
polyethylene/low density polyethylene is preferable as material
that can thermally laminated with microporous film.
[0093] [Paper Layer]
[0094] For the purpose of the invention, the paper of the paper
layer is not subject to any particular limitations. Examples of
paper that can be used for the purpose of the invention include
ordinary paper and Japanese paper made from one or more than one
different types of fiber selected from pulp, kozo, mitsumata,
natural cellulose, regenerated cellulose, rayon, acetate and so on.
The type of paper may be appropriately selected by taking the type
of the object to be packaged, the degree of powderization, the air
permeability and the shape and the size of the package into
consideration.
[0095] The mass per unit area of the paper is normally between 10
and 100 g/m.sup.2, preferably between 12 and 70 g/m.sup.2. The mass
per unit area may be appropriately selected by taking the type of
the object to be packaged, the degree of powderization, the air
permeability and the shape and the size of the package into
consideration.
[0096] [Multilayer Forming Process]
[0097] A packaging multilayer material according to the invention
is formed by sequentially laying a micro-porous film layer or a
paper layer, a polyethylene type resin spunbonded non-woven fabric
layer and an air permeable heat-resistant fiber material layer have
a heat-resistance of not lower than 150.degree. C. and bonding them
by way of a thermal bonding process, which is preferably the
thermal embossing roll method.
[0098] Two of the layers may be laid one on the other in advance.
The operation of laying two layers in advance may be performed by
way of the thermal flat roll method or, preferably, the thermal
embossing roll method. Particularly, when spunbonded non-woven
fabric having a melting point between 150 and 300.degree. C. is
used for the heat-resistant fiber material layer, the operation of
laying a polyethylene type resin spunbonded non-woven fabric layer
and a spunbonded non-woven fabric layer made of polypropylene,
polyamide or polyester one on the other may be conducted on an
in-line basis or, alternatively, the layers may be integrally
formed when they are laid on a micro-porous film layer or a paper
layer in a subsequent step.
[0099] The meaning of providing an air permeable heat-resistant
fiber material layer is that, when a polyethylene type spunbonded
non-woven fabric layer is laid on a microporous film layer or a
paper layer by means of the thermal embossing roll method, the
temperature of one of the rolls can be selected without allowing
the thermal bonding temperature (roll temperature) to be
significantly affected by the melting point of the polyethylene
type resin spunbonded non-woven fabric. Therefore, a wide
temperature range can be secured for the thermal bonding and the
efficiency of forming multilayer structures is remarkably
improved.
[0100] Further, the heat-resistant fiber material layer is not
molten and keeps a strength, thus edges are prevented from being
cut at the time of heat sealing of packages. As a result, a
packaging multilayer material shows an excellent sealing
effect.
[0101] The melting point of each of the thermal plastic resins
constituting the non-woven fabrics and the films that are used for
the purpose of the invention may be defined to be the peak
temperature observed when the temperature rising rate is gauged by
means of a DSC (DSC 7 type: tradename, available from Perkin
Elmer), using a gauging process conforming to JIS K 7121. When the
melting point appears as a plurality of peaks, the highest peak is
used. The melt flow rate (MFR) of the polyethylene type resin can
be gauged by a method conforming to JIS K 7210 under the conditions
of measuring temperature: 190.degree. C. and measuring load:
21.18N.
[0102] Thus, a packaging multilayer material according to the
invention may be formed firstly by laying an air permeable
heat-resistant fiber material layer on a polyethylene type resin
spunbonded non-woven fabric layer, by laying a polyethylene type
resin spunbonded non-woven fabric layer on a micro-porous film
layer or by laying a polyethylene type resin spunbonded non-woven
fabric layer on a micro-porous film layer or a paper layer
depending on the intended layered structure. Two of the layers may
be laid one on the other in advance or all the layers may be bonded
together simultaneously by thermal bonding.
[0103] Any known multilayer structure forming method may be used to
form a packaging multilayer material according to the invention.
However, the thermal embossing roll method is preferably used for
forming a packaging multilayer material according to the invention
because, with this method, the packaging multilayer material is
formed by thermal bonding and no adhesive agent is used there so
that the manufactured packaging multilayer material is flee from
smell due to the use of an adhesive agent and additionally also
flee from any possible reduction of air permeability, while it can
be formed with ease at low cost and the method is friendly to the
environment.
[0104] With the thermal embossing roll method, a known laminating
apparatus comprising an embossing roll and a flat roll may be used.
The embossing roll may carry a desired embossing pattern. Available
patterns include a lattice-shaped pattern where the bonding
sections are continuously formed, a lattice-shaped pattern where
the bonding sections are held independent from each other and a
pattern where the bonding sections are distributed arbitrarily.
[0105] The conditions under which the thermal embossing roll method
is used for forming a multilayer structure may vary depending on
the type and the melting point of each of the microporous film
layer, the paper layer, the polyethylene type resin spunbonded
non-woven fabric layer and the heat-resistant fiber material layer,
the difference of the melting points of the layers, the selected
layer for embossing and so on and determined appropriately by
taking the related factors into consideration. Normally, the
polyethylene type resin spunbonded non-woven fabric layer is placed
at the embossing roll side and the microporous film layer or the
paper layer is placed at the flat roll side when forming a
multilayer structure by thermal bonding.
[0106] As an example, the temperature of the embossing roll is
normally between 90 and 200.degree. C., preferably between 110 and
180.degree. C. and the temperature of the flat roll is normally
between 90 and 200.degree. C., preferably between 110 and
180.degree. C., whereas the roll pressure (linear pressure) is
normally between 100 and 500 N/cm, preferably between 200 and 400
N/cm. Note, however, that the embossing pattern, the percentage of
the embossing area, the temperature and the pressure may be
selected appropriately depending on the melting point, the filament
diameter, the thickness, the mass per unit area, the air
permeability and the multilayer structure forming rate of the
non-woven fabric.
[0107] [Requirements to be Met by Multilayer Material]
[0108] A packaging multilayer material according to the invention
is required to be appropriately air permeable and moisture
permeable to such an extent that the functional agent contained in
it can operate properly. The air permeability and moisture
permeability may vary depending on the type of the functional
article, the size of the package and the application of the
functional article. Generally, the materials of the layers are
selected in such a way that the moisture permeability is held to be
less than 50 g/m.sup.2.multidot.24 hours and the contents may not
leak out.
[0109] A packaging multilayer material according to the invention
can be used to package a functional article mainly selected from
deoxidizing agents and moisture absorbing agents. In the case of a
bag-shaped package, at least part of the bag, preferably a side of
the bag is formed by a packaging material according to the
invention. Any heat-sealing method adapted to heating thermoplastic
resin and bonding it under pressure may be used without limitations
for the purpose of the invention. Heat-sealing methods that can be
used for the purpose of the invention include a method using a hot
sealing bar and the continuous sealing method that is popularly
used in the field of bag manufacturing and sewing. Thermal
conduction (heat jig, heat generating body), dielectric heating or
ultrasonic heating may be used as heating means for the purpose of
the invention.
[0110] The temperature, the pressure, the duration and the rate of
heat-sealing operation may be selected appropriately depending on
the type, the heat-resistance (melting point), the molecular
weight, the thickness and the mass per unit area of the
polyethylene type resin spunbonded non-woven fabric, those of the
air permeable heat-resistant fiber material layer, and those of the
micro-porous film.
[0111] A packaging multilayer material according to the invention
can suitably be used for packaging a functional article that may be
a deoxidizing agent, a drying agent, a moisture absorbing agent, a
deodorant, a heat generating agent, an insecticide, a desiccating
agent or an aromatic agent Particularly, because a packaging
multilayer material according to the invention shows an excellent
sealing effect, it can be applied to sheet-shaped packages having a
relatively large surface area and adapted to contain a deodorant
such as charcoal or active carbon. For such an application, a
number of sheet-shaped packages will be continuously formed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0112] FIG. 1 is a schematic illustration of a thermal laminating
apparatus that can be used for the first embodiment of the
invention;
[0113] FIG. 2 is a schematic cross sectional view of the first
embodiment of packaging multilayer material;
[0114] FIG. 3 is a schematic illustration on of a thermal
laminating apparatus that can be used for the second embodiment of
the invention; and
[0115] FIG. 4 is a schematic cross sectional view of the embodiment
of packaging multilayer material of FIG. 3.
BEST MODE FOR CARRYING OUT THE INVENTION
[0116] Now, the present invention will be described by referring to
the accompanying drawings that illustrate preferred embodiments of
the invention.
[0117] [1st Embodiment]
[0118] The first embodiment is a three-layered packaging multilayer
material having an air permeable heat-resistant fiber material
layer, a polyethylene type resin spunbonded non-woven fabric layer
and a micro-porous film layer.
[0119] FIG. 1 is a schematic illustration of a thermal laminating
apparatus 1 that can be used for the first embodiment of the
invention.
[0120] The thermal laminating apparatus 1 comprises a feed roll 4
for feeding a multilayer sheet 10, another feed roll 5 for feeding
a micro-porous sheet 13, a flat roll 6 and an embossing roll 7 for
pinching the multilayer sheet 10 and the micro-porous sheet 13
under pressure and a take up roll 8 for taking up the produced
packaging multilayer material 14.
[0121] The multilayer sheet 10 is formed in advance by laying a
polyethylene type resin spunbonded non-woven fabric 12 and an air
permeable heat-resistant fiber material 11 one on the other by
means of thermal lamination.
[0122] The feed rolls 4, 5 and the take up roll 8 may be made of
any materials so long as they operate properly to achieve the
intended object.
[0123] The flat roll 6 has a smooth surface and is provided with a
heating means that can change the temperature thereof in a desired
manner. It is placed on the sheets to be pinched by it under
pressure. Additionally, the flat roll 6 may be connected to a drive
means such as a motor and driven to rotate.
[0124] The embossing roll 7 carries on the surface thereof a
desired embossing pattern and is provided with a heating means that
can change the temperature thereof in a desired manner. It is
placed under the sheets to be pinched by it under pressure.
[0125] The packaging multilayer material 14 that is produced from
the gap between the flat roll 6 and the embossing roll 7 after
raising the temperature of the flat roll 6 and that of the
embossing roll 7 is formed by laying an air permeable
heat-resistant fiber material 11, a polyethylene type resin
spunbonded non-woven fabric 12 and a microporous sheet 13 in the
above mentioned order as viewed from the flat roll 6.
[0126] A predetermined embossing pattern is formed on the surface
of the micro-porous sheet 13 by the embossing roll 7.
[0127] Thus, as shown in FIG. 2, the finished packaging multilayer
material 14 has a layer of the air permeable heat-resistant fiber
material 11, a layer of the polyethylene type resin spunbonded
non-woven fabric 12 and a layer of the microporous sheet 13.
[0128] Packages (not shown) containing silica gel are manufactured
by using the packaging multilayer material 14 obtained in a manner
as described above. At the time of manufacturing, each packaging
multilayer material 14 is sealed along the periphery thereof by a
heat-sealing means.
[0129] Thus, this embodiment provides the following advantages.
[0130] A packaging multilayer material 14 according to the
invention is air permeable and moisture permeable and shows a
barrier effect against fine powder and also an excellent sealing
effect. Therefore it is suited for packaging a functional article
such as a deoxidizing agent or a moisture absorbing agent.
Additionally, since no adhesive agent is used for forming the
multilayer material, the manufacturing process is an easy one and
the product is flee from degradation of air permeability, that of
moisture permeability and smell and hence can be used to package a
wide variety of functional articles.
[0131] [2nd Embodiment]
[0132] The second embodiment is a four-layered packaging multilayer
material having an air permeable heat-resistant fiber material
layer, a polyethylene type resin spunbonded non-woven fabric layer,
a micro-porous film layer and an air permeable material layer.
[0133] FIG. 3 is a schematic illustration of a thermal laminating
apparatus 2 that can be used for the second embodiment of the
invention. In the following description, the components same as
those of the first embodiment are denoted respectively by the same
reference symbols and will not be described any further.
[0134] The thermal laminating apparatus 2 comprises a feed roll 4
for feeding a multilayer sheet 20, another feed roll 5 for feeding
a micro-porous sheet 23, still another feed roll 9 for feeding an
air permeable material 24, flat rolls 6, 16 for pinching the
multilayer sheet 20, the micro-porous sheet 13 and the air
permeable material 24 under pressure and a take up roll 8 for
taking up the produced packaging multilayer material 25.
[0135] The multilayer sheet 20 is formed in advance by laying a
polyethylene type resin spunbonded non-woven fabric 22 and an air
permeable heat-resistant fiber material 21 one on the other by
means of thermal lamination.
[0136] The feed rolls 9 may also be made of any materials so long
as it operates properly to achieve the intended object.
[0137] Like the flat roll 6, the flat roll 16 has a smooth surface
and is provided with a heating means that can change the
temperature thereof in a desired manner. It is placed under the
sheets to be pinched by it under pressure.
[0138] The packaging multilayer material 25 that is produced as a
result of the thermal laminating operation is formed by laying an
air permeable heat-resistant fiber material 21, a polyethylene type
resin spunbonded non-woven fabric 22, a micro-porous sheet 23 and
an air permeable material 24 in the above mentioned order as viewed
from the flat roll 6.
[0139] Thus, as shown in FIG. 4, the finished packaging multilayer
material 25 has a layer of the air permeable heat-resistant fiber
material 21, a layer of the polyethylene type resin spunbonded
non-woven fabric 22, a layer of the micro-porous sheet 23 and a
layer of the air permeable material 24.
[0140] This embodiment provides the following advantage in addition
to the advantages of the first embodiment.
[0141] As a layer of an air permeable material 24 added to the
packaging multilayer material 25, the latter shows an improved
strength and its edges are prevented from being cut during the
heat-sealing operation.
[0142] [3rd Embodiment]
[0143] The third embodiment is a three-layered packaging multilayer
material having an air permeable heat-resistant fiber material
layer, a polyethylene type resin spunbonded non-woven fabric layer
and a paper layer.
[0144] Such a three-layered multilayer material can be manufactured
by using a thermal laminating apparatus 1 as described above by
referring to the first embodiment (see FIG. 1). Note that, however,
a roll carrying not a microporous sheet 13 but a paper sheet is
used for the feed roll 5. Then, a multilayer sheet 10 of an air
permeable heat-resistant fiber material 11 and a polyethylene type
resin spunbonded non-woven fabric 12 fed out from the feed roll 4
and a paper sheet (13) fed out from the feed roll 5 are thermally
bonded together to produce a three-layered packaging multilayer
material.
[0145] This embodiment is a packaging multilayer material that
provides a good sealing effect and an excellent productivity as
well as the air permeability and the printing effect specific to
paper.
[0146] [4th Embodiment]
[0147] The fourth embodiment is a two-layered packaging multilayer
material having only a polyethylene type resin spunbonded non-woven
fabric layer and a paper layer.
[0148] Such a two-layered multilayer material can be manufactured
by a known thermal laminating apparatus. Alternatively, a thermal
laminating apparatus 1 as described above by referring to the first
embodiment (see FIG. 1) may be used. Note, however, that a roll
carrying only polyethylene type resin spunbonded non-woven fabric
12 is used for the feed roll 4 in place of a roll carrying a
multilayer sheet 10 of an air permeable heat-resistant fiber
material 11 and a roll carrying not a microporous sheet 13 but a
paper sheet is used for the feed roll 5. Then, the two layers of
the raw materials are thermally bonded.
[0149] This embodiment is a packaging multilayer material that
provides a good sealing effect and an excellent productivity as
well as the air permeability and the printing effect specific to
paper. Particularly, it is structurally simple and hence ideally
suited for light packages because it only has two layers including
a paper layer.
[0150] A packaging multilayer material according to the invention
will be described in greater detail below by way of examples and
examples for comparison, although the present invention is by no
means limited thereto.
EXAMPLE 1
[0151] A three-layered packaging multilayer material 14 was
prepared by using a thermal laminating apparatus 1 as described
above for the first embodiment.
[0152] The thermal laminating apparatus 1 was a thermal laminating
machine marketed by Sansei Seiki Co., Ltd. [oil temperate
regulation type, roll diameter: 300 mm, embossing roll/flat roll,
percentage of embossing contact area: 21%, lattice pattern (pitch:
1.5 mm), embossing pressure (linear pressure): 300 N/cm, laminating
rate: 15 m/min].
[0153] Firstly, polyethylene type spunbonded non-woven fabric
available from Idemitsu Petrochemical Co., Ltd. ["STRATEC" LN5020
(raw material: ethylene-butene-1 copolymer with density: 940
kg/m.sup.3, filament diameter: 25 .mu.m, mass per unit area: 20
g/m.sup.2, melting point: 124.degree. C.)] was used for the
polyethylene type resin spunbonded non-woven fabric 12 and
polyester spunbonded non-woven fabric available from Toyobo Co.,
Ltd. ["Ecule A" 6301 (mass per unit area: 30 g/m.sup.2, melting
point: 260.degree. C.)] was used for the air permeable
heat-resistant fiber material layer 11, which two layers were
thermally laminated to obtain a two-layered multilayer sheet
10.
[0154] Then, drawn PE moisture film " PU35" (thickness: 35 .mu.m)
containing inorganic filler available from Tokuyama Corporation was
used for the microporous film layer 13 and placed at the side of
the polyethylene non-woven fabric 12 of the two-layered multilayer
sheet 10. The film surface was used surface to be embossed and all
the layers were put together by thermal lamination to produce a
three-layered packaging multilayer material 14.
[0155] It was possible to conduct the thermal bonding operation
with emboss roll temperature: 85.degree. C. and a wide temperature
range between 115 and 155.degree. C. for the flat roll.
[0156] The obtained packaging multilayer material 14 was assessed
for the following physical properties.
[0157] (1) Bonding Strength
[0158] The bonding strength was observed by means of a tensile test
machine with a pulling rate of 200 mm/min and a peeling angle of
180 degrees (r-peeling), using a sample width of 50 mm and a chuck
interval of 50 mm and the average was obtained for N=5.
[0159] As a result, it was found that the bonding strength was
about 1.1 to 2.4 N/50 mm in the longitudinal direction.
[0160] (2) Tensile Strength
[0161] The tensile strength was observed by a method conforming to
JIS L 1906.
[0162] As a result, it was found that the tensile strength was
longitudinally 62 to 64 N/50 mm and transversally 35 to 36 N/50
mm.
[0163] (3) Moisture Permeability
[0164] The moisture permeability was observed by a method
conforming to JIS Z 0208 (cup method).
[0165] As a result, it was found that the moisture permeability was
2,500 to 5,000 g/m.sup.2.multidot.24 hours.
[0166] (4) Water Pressure Resistance
[0167] The resistance against water pressure was observed by a
method conforming to JIS L 1092 (high water pressure method).
[0168] As a result, it was found that the resistance against water
pressure was not lower than 20 kPa under any conditions.
[0169] (5) Sealing Strength
[0170] A thermal gradient testing machine was used to heat-seal the
surfaces of the micro-porous film layers of the multilayer material
under heat-sealing conditions of heat-sealing temperature:
180.degree. C., sealing bar: 15 mm.times.15 mm, sealing pressure
40N and sealing time: 1 second.
[0171] As a result, it was found that the heat-sealing strength was
11 N/15 mm.
EXAMPLE 2
[0172] The three-layered multilayer material obtained in Example 1
was used to continuously package 100 mm.times.60 mm pieces of a
drying agent (silica gel) at a rate of 60 shots/min at heat-sealing
temperature of 180.degree. C.
[0173] As a result, it was possible to obtain good packages in
which no silica gel was drawn into the sealing sections and that
showed a sealing strength of 12 N/15 mm width.
EXAMPLE 1 FOR COMPARISON
[0174] For the purpose of comparing with Example 2, packages were
prepared by using a packaging material having a single micro-porous
film layer, a two-layered multilayer packaging material having a
microporous film layer and a polyethylene non-woven fabric layer
and a packaging material of flash spinning non-woven fabric "TYVEK"
[tradename; available from Asahi DuPont Flashbond Products Co.,
Ltd.] with mass per unit area of 46 g/m.sup.2.
[0175] As a result, it was found that bags could not be formed due
to cut edges. Additionally, the sealing bar was smeared.
EXAMPLE 3
[0176] A packaging multilayer material 25 was prepared by using a
thermal laminating apparatus 2 as described above by referring to
the second embodiment "STRAMIGHTY ME1045 (mass per unit area of 45
g/m.sup.2)" available from Idemitsu Unitech was used for the
multilayer sheet 20 of an air permeable heat-resistant fiber
material 21 and a polyethylene type resin spunbonded non-woven
fabric 22 and drawn polyethylene film containing an inorganic
filler (thickness: 35 .mu.m) available from Tokuyama Corporation
with the tradename of " PU35" was used for the micro-porous sheet
23, while above described "STRAMIGHTY ME1045" (PET spunbonded
layer/LLDPE spunbonded layer) available from Idemitsu Unitech was
used for the air permeable material 24.
[0177] The multilayer non-woven fabric ME1045 was fed out in such a
way that the LLDPE spunbonded layer comes to meet the bonding
surface of the micro-porous sheet 23 to obtain a packaging
multilayer material 25.
[0178] For the forming operation, flat rolls 6, 16 were used with
roll temperature of 140.degree. C. for the flat roll 6 and
115.degree. C. for the flat roll 16 and the operation was conducted
at a processing rate of 25 m/min under linear pressure of 25
kg/cm.
EXAMPLE 4
[0179] A packaging multilayer material 25 was prepared under
conditions same as those of Example 3 except that polyolefin type
flat yarn biaxial thermally bonded type multilayer non-woven fabric
"sohu HM55 (mass per unit area of 32 g/m.sup.2" available from
Sekisui Chemicals Co., Ltd. was used for the air permeable material
24.
[0180] The specimens of Examples 3 and 4 were assessed for the
following physical properties.
[0181] (1) Tensile Strength
[0182] The tensile strength was observed by a method conforming to
JIS L 1906.
[0183] As a result, it was found that the tensile strength of
Example 3 was 140 N/50 mm in the MD and 80 N/50 mm in the TD,
whereas that of Example 4 was 400 N/50 mm in the MD and 380 N/50 mm
in the TD. Note that MD is the film moving direction and the TD is
a direction perpendicular to the MD.
[0184] (2) Moisture Permeability
[0185] The moisture permeability was observed by a method
conforming to JIS Z 0208 (cup method).
[0186] As a result, it was found that the moisture permeability of
Example 3 was 4,000 g/m.sup.2.multidot.24 hours and that of Example
4 was 4,200 g/m.sup.2.multidot.24 hours
[0187] (3) Water Pressure Resistance
[0188] The resistance against water pressure was observed by a
method conforming to JIS L 1092 (high water pressure method).
[0189] As a result, it was found that the resistance against water
pressure of both Example 3 and Example 4 was not lower than 50
kPa.
[0190] (4) Air Permeability
[0191] The air permeability was observed by a method conforming to
JIS L 1096 ( method).
[0192] As a result, it was found that the air permeability of
Example 3 was 650 seconds and that of Example 4 was 600
seconds.
[0193] (5) Sealing Strength
[0194] Each of the specimen to be assessed was sealed with dry
laminate film (ONY 15 .mu.m/LL 50 .mu.m). Note that ONY represents
drawn nylon and LL represents LLDPE (linear low density
polyethylene)
[0195] Then, the LL surface of each of the dry laminated produce
was heat-sealed. A thermal gradient testing machine was used for
the heat-sealing with sealing pressure: 4 kgf and sealing time: 1
second.
[0196] A tensile test machine was used and the sealing strength was
observed with a pulling rate of 200 m/min.
[0197] As a result, it was found that the heat-sealing strength of
Example 3 was 37 N/50 mm and that of Example 4 was 34 N/50 mm.
[0198] As seen from Examples 3 and 4, the sealing strength of
Example 3 was improved without damaging the moisture permeability,
the resistance against water pressure and the air permeability by
laying and bonding an air permeable material by thermal
lamination.
EXAMPLE 5
[0199] A three-layered packaging multilayer material including a
paper layer was prepared on the basis of the third embodiment.
[0200] The thermal laminating apparatus was a thermal laminating
machine marketed by Sansei Seiki Co., Ltd. [oil temperature
regulation type, roll diameter: 300 mm, flat roll/flat roll, roll
temperature: 150.degree. C., pressure (linear pressure): 300 N/cm,
laminating rate: 7 m/min].
[0201] Firstly, two-layered spunbonded non-woven fabric comprising
a polyethylene type resin spunbonded non-woven fabric layer
(ethylene-butene-1 copolymer same as that of Example 1) and an air
permeable heat-resistant fiber material layer
(polyethyleneterephthalate) [mass per unit area 45 g/m.sup.2
(former: 30 g/m.sup.2, latter: 15 g/m.sup.2)] was used and rayon
paper available from Okura Paper Manufacturing Co., Ltd. [mass per
unit area: 30 g/m.sup.2] was laid thereon at the side of the
polyethylene type resin spunbonded non-woven fabric layer to
produce a three-layered packaging multilayer material including a
paper layer.
[0202] The obtained three layered packaging multilayer material
including a paper layer was assessed for the following physical
properties.
[0203] (1) Heat-Sealing Effect
[0204] A thermal gradient testing machine was used to heat-seal the
surfaces of non-woven fabric of the obtained packaging multilayer
material and the LLDPE surface of a commercially available
multilayer film [drawn nylon (ONy): 15 .mu.m/straight chain low
density polyethylene (LLDPE): 50 .mu.m] [heat-sealing temperature:
180.degree. C., sealing bar: 15 mm.times.15 mm, sealing pressure
20N and sealing time: 1 second].
[0205] The heat-sealed area of the obtained specimen was subjected
to a 180 degrees peeling (T-peeling) test with a pulling speed of
200 m/min to observe the bonding strength.
[0206] As a result, it was found that the heat-sealing strength was
3.2 kg/15 mm.
[0207] (2) Hot Tuck Effect
[0208] The non-woven fabric surfaces of the obtained packaging
multilayer material were heat-sealed [heat-sealing temperature:
190.degree. C., sealing bar: 15 mm.times.300 mm, sealing pressure
20N and sealing time: 5 seconds]. Immediately after the sealing
operation, the sealing bar was removed and the sealed surface was
peeled to observe the length of the peeled part.
[0209] As a result, it was found that the peeled length was only 25
mm and the specimen showed an excellent hot tuck effect.
EXAMPLE 2 FOR COMPARISON
[0210] For the purpose of comparing with Example 5, a two-layered
air permeable packaging multilayer material was prepared by using
skin-core type bicomponent non-woven fabric of PET
(core)/polyethylene (skin) ["ELEVES": tradename, available from
Kanbo Co., Ltd., mass per unit area: 40 g/m.sup.2] for the
non-woven fabric and rayon paper available from Okura Paper
Manufacturing Co., Ltd [mass per unit area: 30 g/m.sup.2] for the
paper and the bicomponent non-woven fabric side was used for
embossing in the heat-sealing operation [embossing roll
temperature: 115.degree. C., flat roll temperature: 150.degree. C.,
embossing pressure: 300 N/cm, laminating rate: 7 m/min].
[0211] The multilayer material was assessed as in Example 5.
[0212] As a result, it was found that, while the heat-sealing
strength was 2.7 kg/15 mm, the peeled length was 200 mm to prove a
poor hot tuck effect.
EXAMPLE 6
[0213] The three-layered packaging multilayer material obtained in
Example 5 including a paper layer and commercially available
multilayer film used in Example 5 for heat-sealing effect were used
to continuously produce bag-shaped packages of 200 mm.times.300 mm
at a rate of 20 shots/min at heat-sealing temperature of
200.degree. C.
[0214] As a result, it was possible to obtain good packages in
which no edges were cut in the sealing sections and no defective
seals were found. The sealing strength was 3.1 kg/15 mm width.
EXAMPLE 7
[0215] A two-layered packaging multilayer material including a
paper layer was prepared on the basis of the fourth embodiment.
[0216] The thermal laminating apparatus 1 was a thermal laminating
machine marketed by Sansei Seiki Co., Ltd [oil temperature
regulation type, roll diameter: 300 mm, embossing roll/flat roll,
embossing roll temperature: 115.degree. C., flat roll temperature:
130.degree. C., percentage of embossing contact area: 21%, lattice
pattern (pitch: 1.5 mm), embossing pressure (linear pressure): 300
N/cm, laminating rate: 7 m/min].
[0217] Firstly, polyethylene spunbonded non-woven fabric was used
for the polyethylene type resin spunbonded non-woven fabric layer
as in Example 1 and rayon paper available from Okura Paper
Manufacturing Co., Ltd [mass per unit area: 20 g/m.sup.2] was
thermally bonded as paper layer to a surface of the polyethylene
spunbonded non-woven fabric, which was used as the side to be
embossed, to produce a two-layered packaging multilayer material
including a paper layer.
[0218] The obtained two-layered packaging multilayer material
including a paper layer was assessed in a manner as described
below.
[0219] The surface of the non-woven fabric of the obtained
packaging multilayer material was heat-sealed under the following
conditions. A high speed packing/packaging machine available from
Komatsu Ltd. was used for the sealing operation in a die roll mode.
A satin finish was used for the die roll and the packaging
operation was conducted at a rate of 60 shots/min at sealing
temperature of 205.degree. C. and under sealing pressure of
7.18N.
[0220] The heat-sealed area of each of the obtained specimens was
subjected to a 180 degrees peeling (F-peeling) test with a pulling
speed of 200 m/min to observe the bonding strength.
[0221] As a result, it was found that the heat-sealing strength was
1.2 kg/15 mm width. No smear was found on the die roll.
EXAMPLE 3 FOR COMPARISON
[0222] For the purpose of comparing with Example 7, heat-sealing
paper [mass per unit area: 20 g/m.sup.2], which is mixed paper of
pulp and thermally bonded fiber (HDPE/PP) available from Mishima
Paper Co., Ltd., was heat-sealed as in Example 7 and the
heat-sealing strength was observed.
[0223] As a result, it was found that the heat-sealing strength was
0.8 kg/15 mm width. Additionally, the die roll was smeared.
EXAMPLE 8
[0224] The two-layered packaging multilayer material obtained in
Example 7 and including a paper layer was used to continuously
package 100 mm.times.60 mm pieces of a drying agent (silica gel) at
a rate of 60 shots/min at heat-sealing temperature of 160.degree.
C.
[0225] As a result, it was possible to obtain good packages in
which no silica gel was drawn into the sealing sections and that
showed a sealing strength of 1.1 kg/15 mm width.
INDUSTRIAL APPLICABILITY
[0226] This invention relates to a packaging multilayer material
and also to a package formed by using such a multilayer material.
The present invention provides a packaging multilayer material for
packaging a functional article such as a deoxidizing agent, a
drying agent or a desiccating agent and also a package formed by
using such a multilayer material.
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