U.S. patent application number 09/867603 was filed with the patent office on 2001-10-25 for poly-4-methyl-1-pentene resin laminates and uses thereof.
This patent application is currently assigned to Mitsui Chemicals, Inc.. Invention is credited to Kubo, Mineo, Nakahara, Takashi, Tanizaki, Tatsuya.
Application Number | 20010033940 09/867603 |
Document ID | / |
Family ID | 26337729 |
Filed Date | 2001-10-25 |
United States Patent
Application |
20010033940 |
Kind Code |
A1 |
Tanizaki, Tatsuya ; et
al. |
October 25, 2001 |
Poly-4-methyl-1-pentene resin laminates and uses thereof
Abstract
A poly-4-methyl-1-pentene resin laminate excellent in not only
heat sealing properties and oxygen gas permeability but also
blocking resistance is provided. The poly-4-methyl-1-pentene resin
laminate comprises a layer made of a 4-methyl-1-pentene polymer
(A), an intermediate layer made of an adhesive resin composition
(B) and a layer made of a propylene polymer composition (C)
comprising 60 to 90 parts by weight of a propylene polymer (c-1)
and 10 to 40 parts by weight of a 1-butene polymer (c-2), the total
amount of said components (c-1) and (c-2) being 100 parts by
weight. This poly-4-methyl-1-pentene resin laminate can be used as
a material of freshness-keeping packaging media and culture
containers. Also provided is a poly-4-methyl-1-pentene resin
laminate having excellent peel resistance and capable of being
easily controlled in the oxygen gas permeability. This
poly-4-methyl-1-pentene resin laminate comprises a layer made of a
4-methyl-1-pentene polymer (A'), an intermediate layer made of an
adhesive resin composition (B') and a layer made of an olefin
polymer (C'). This poly-4-methyl-1-pentene resin laminate can be
used as a material of containers for keeping freshness of
vegetables and fruits.
Inventors: |
Tanizaki, Tatsuya;
(Kuga-gun, JP) ; Nakahara, Takashi; (Kuga-gun,
JP) ; Kubo, Mineo; (Kuga-gun, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Mitsui Chemicals, Inc.
|
Family ID: |
26337729 |
Appl. No.: |
09/867603 |
Filed: |
May 31, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09867603 |
May 31, 2001 |
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09147961 |
Mar 24, 1999 |
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6265083 |
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09147961 |
Mar 24, 1999 |
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PCT/JP98/03708 |
Aug 21, 1998 |
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Current U.S.
Class: |
428/516 ;
428/515 |
Current CPC
Class: |
Y10T 428/31913 20150401;
B32B 27/32 20130101; B32B 2323/04 20130101; B32B 27/08 20130101;
Y10T 428/31909 20150401; B32B 2323/10 20130101; B32B 2439/00
20130101; B32B 7/12 20130101 |
Class at
Publication: |
428/516 ;
428/515 |
International
Class: |
B32B 027/32; B32B
027/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 1997 |
JP |
226151/1997 |
Jan 12, 1998 |
JP |
4025/1998 |
Claims
What is claimed is:
1. A poly-4-methyl-1-pentene resin laminate comprising: (I) a layer
made of a 4-methy-1-pentene polymer (A'), (II) an intermediate
layer made of an adhesive resin composition (B'), and (III) a layer
made of an olefin polymer (C').
2. The poly-4-methyl-1-pentene resin laminate as claimed in claim
1, wherein the adhesive resin composition (B') is a composition
comprising a 4-methyl-1-pentene polymer (b-1) and a 1-butene
polymer (b-2).
3. The poly-4-methyl-1-pentene resin laminate as claimed in claim
2, wherein the adhesive resin composition (B') is a composition
containing the 4-methyl-1-pentene polymer (b-1) in an amount of 40
to 97.5 parts by weight and the 1-butene polymer (b-2) in an amount
of 2.5 to 60 parts by weight, the total amount of said components
(b-1) and (b-2) being 100 parts by weight.
4. The poly-4-methyl-1-pentene resin laminate as claimed in claim
1, wherein the olefin polymer (C') is a propylene polymer (c-1),
and the adhesive resin composition (B') is a composition comprising
a 4-methyl-1-pentene polymer (b-1) and a 1-butene polymer (b-2) and
containing the 4-methyl-1-pentene polymer (b-1) in an amount of 40
to 97.5 parts by weight and the 1-butene polymer (b-2) in an amount
of 2.5 to 60 parts by weight, the total amount of said components
(b-1) and (b-2) being 100 parts by weight.
5. The poly-4-methyl-1-pentene resin laminate as claimed in claim
1, wherein the adhesive resin composition (B') is a composition
comprising a 4-methyl-1-pentene polymer (b-1), a 1-butene polymer
(b-2) and a propylene polymer (b-3).
6. The poly-4-methyl-1-pentene resin laminate as claimed in claim
5, wherein the adhesive resin composition (B') is a composition
containing the 4-methyl-1-pentene polymer (b-1) in an amount of 40
to 97.5 parts by weight and the 1-butene polymer (b-2) in an amount
of 2.5 to 60 parts by weight, the total amount of said component
(b-1) and (b-2) being 100 parts by weight, and containing the
propylene polymer (b-3) in an amount of 1 to 100 parts by weight
based on 100 parts by weight of the total amount of the components
(b-1) and (b-2).
7. The poly-4-methyl-1-pentene resin laminate as claimed in claim
1, wherein the olefin polymer (C') is a propylene polymer (c-4),
and the adhesive resin composition (B') is a composition comprising
a 4-methyl-1-pentene polymer (b-1), a 1-butene polymer (b-2) and a
propylene polymer (b-3), containing the 4-methyl-1-pentene polymer
(b-1) in an amount of 40 to 97.5 parts by weight and the 1-butene
polymer (b-2) in an amount of 2.5 to 60 parts by weight, the total
amount of said components (b-1) and (b-2) being 100 parts by
weight, and containing the propylene polymer (b-3) in an amount of
1 to 100 parts by weight based on 100 parts by weight of the total
amount of the components (b-1) and (b-2).
8. The poly-4-methyl-1-pentene resin laminate as claimed in claim
1, wherein the olefin polymer (C') is an ethylene polymer (c-5),
and the adhesive resin composition (B') is a composition comprising
a 4-methyl-1-pentene polymer (b-1), a 1-butene polymer (b-2), and
ethylene/butene copolymer (b-4), and optionally, a propylene/butene
copolymer (b-5) and containing the 4-methyl-1-pentene polymer (b-1)
in an amount of 20 to 60 parts by weight, the 1-butene polymer
(b-2) in an amount of 5 to 40 parts by weight, the ethylene/butene
copolymer (b-4) in an amount of 30 to 60 parts by weight and the
propylene/butene copolymer (b-5) in an amount of 0 to 30 parts by
weight, the total amount of said components (b-1), (b-2), (b-4) and
(b-5) being 100 parts by weight.
9. A packaging medium having excellent oxygen permeability, which
comprises the poly-4-methyl-1-pentene resin laminate as claimed in
claim 1.
10. A packaging medium for keeping freshness of vegetables and
fruits, which comprises the poly-4-methyl-1-pentene resin laminate
as claimed in claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to poly-4-methyl-1-pentene
resin laminates. More particularly, the invention relates to
poly-4-methyl-1-pentene laminates having excellent gas
permeability, heat sealing properties and blocking resistance,
poly-4-methyl-1-pentene resin laminates capable of being easily
controlled in the gas permeability and packaging media formed from
the laminates.
BACKGROUND ART
[0002] Because of their excellent heat resistance, transparency,
gas permeability and mold release characteristics,
4-methyl-1-pentene polymers have been employed for, for example,
plates for electronic oven, release films for FPC, process paper
for artificial leather, baking cartons, medical syringes, storage
containers of medicines, agricultural chemicals, cosmetics, blood
or the like, measuring equipment, and storage containers of
perishable foods. The 4-methyl-1-pentene polymers, however, have
poor heat sealing strength, and they have been desired to be
further improved in the practical performance.
[0003] In order to impart heat sealing properties to the
4-methyl-1-pentene polymers, a method of laminating the
4-methyl-1-pentene polymers to other thermoplastic resins such as
polyolefins has been studied. However, if the 4-methyl-1-pentene
polymers are laminated to other thermoplastic resins, the gas
permeability that is an excellent property inherent in the
4-methyl-1-pentene polymers is deteriorated. In addition, the
4-methyl-1-pentene polymers have a problem of low adhesion
strength.
[0004] Under such circumstances as mentioned above, the present
inventors have earnestly studied, and as a result, they have found
that a laminate consisting of a layer of a 4-methyl-1-pentene
polymer, an intermediate layer of an adhesive resin composition and
a layer of a specific propylene polymer composition is excellent in
not only heat sealing properties and gas permeability but also
blocking resistance. Based on the finding, the present invention
has been accomplished.
[0005] The present inventors have further found that a laminate
consisting of a layer of a 4-methyl-1-pentene polymer, an
intermediate layer of a specific adhesive resin composition and a
layer of an olefin polymer is favorable for storage of vegetables
and fruits.
[0006] It has been hitherto known that vegetables and fruits are
packaged with packaging media to prevent rotting or deterioration
or to keep freshness. For example, vegetables such as lettuce,
sweet pepper, broccoli, asparagus, spinach and mushroom, or fruits
such as peach are packaged with packaging media made of
polypropylene, low-density polyethylene, polybutadiene and the like
to keep freshness. However, it is particularly difficult to keep
freshness of vegetables and fruits having high respiration rates,
such as broccoli and asparagus, so that development of packaging
media capable of keeping freshness for a long period of time has
been desired.
[0007] It is generally said that use of packaging media having
excellent gas permeability is desirable to keep freshness of
vegetables and fruits having high respiration rates. In order to
increase gas permeability of the packaging media, a method of
thinning the packaging media can be thought, but if the packaging
media are thinned, it becomes difficult to maintain strength
appropriate for packaging media. Further, there is a limit to the
thickness of the packaging media because production of thin
packaging media is accompanied by technical difficulty. A method of
incorporating a filler into a resin to increase gas permeability of
the packaging media can also be thought, but there resides a
problem of occurrence of pinholes in this method. In Japanese
Patent Laid-Open Publications No. 168398/1993, No. 260892/1993, No.
22686/1994 and No. 264975/1995, a method of opening fine holes in
the packaging media to increase gas permeability is described. This
method, however, is undesirable from the hygienic viewpoint because
there is a possibility of entering of bacteria through the
holes.
[0008] On the other hand, it is said that vegetables and fruits
having low respiration rates are desired to be packaged with
packaging media having low gas permeability to keep freshness.
[0009] Thus, as materials of the packaging media for keeping
freshness of vegetables and fruits, those having gas permeability
corresponding to the respiration rate should be employed. In the
prior art, however, it was difficult to control gas permeability of
the packaging media over a wide range of high permeability to low
permeability.
[0010] Under such circumstances as mentioned above, the present
inventors have earnestly studied, and as a result, they have found
that a laminate consisting of a layer of a 4-methyl-1-pentene
polymer, an intermediate layer of a specific adhesive resin
composition and a layer of an olefin polymer has excellent peel
resistance and can be easily controlled in the gas permeability.
Based on the finding, the present invention has been
accomplished.
DISCLOSURE OF THE INVENTION
[0011] One embodiment of the poly-4-methyl-1-pentene resin laminate
according to the invention comprises:
[0012] (I) a layer made of a 4-methyl-1-pentene polymer
[0013] (II) an intermediate layer made of an adhesive resin
composition (B), and
[0014] (III) a layer made of a propylene polymer composition (C)
comprising 60 to 90 parts by weight of a propylene polymer (c-1)
and 10 to 40 parts by weight of a 1-butene polymer (c-2), the total
amount of said components (c-1) and (c-2) being 100 parts by
weight.
[0015] Another embodiment of the poly-4-methyl-1-pentene resin
laminate according to the invention comprises:
[0016] (I) a layer made of a 4-methyl-1-pentene polymer (A),
[0017] (II) an intermediate layer made of an adhesive resin
composition (B), and
[0018] (III) a layer made of a propylene polymer composition (C)
comprising 60 to 90 parts by weight of a propylene polymer (c-1)
and 10 to 40 parts by weight of a propylene/ethylene copolymer
(c-3), the total amount of said components (c-1) and (c-3) being
100 parts by weight.
[0019] In the present invention, the 4-methyl-1-pentene polymer (A)
is preferably a 4-methyl-1-pentene homopolymer or a
4-methyl-1-pentene copolymer containing constituent units derived
from 4-methyl-1-pentene in amounts of not less than 85% by weight,
and the adhesive resin composition (B) is preferably a composition
comprising a 4-methyl-1-pentene polymer (b-1) and a 1-butene
polymer (b-2) and containing the 4-methyl-1-pentene polymer (b-1)
in an amount of 40 to 70 parts by weight and the 1-butene polymer
(b-2) in an amount of 30 to 60 parts by weight, the total amount of
said components (b-1) and (b-2) being 100 parts by weight.
[0020] The poly-4-methyl-1-pentene resin laminates mentioned above
have excellent gas permeability and heat sealing properties.
[0021] A further embodiment of the poly-4-methyl-1-pentene resin
laminate according to the invention comprises:
[0022] (I) a layer made of a 4-methyl-1-pentene polymer (A'),
[0023] (II) an intermediate layer made of an adhesive resin
composition (B'), and
[0024] (III) a layer made of an olefin polymer (C').
[0025] The 4-methyl-1-pentene resin laminate of the above
embodiment includes the following laminates:
[0026] (1) a laminate wherein the adhesive resin composition (B')
is a composition comprising a 4-methyl-1-pentene polymer (b-1) and
a 1-butene polymer (b-2);
[0027] (2) a laminate wherein the adhesive resin composition (B')
is a composition comprising a 4-methyl-1-pentene polymer (b-1) and
a 1-butene polymer (b-2) and containing the 4-methyl-1-pentene
polymer (b-1) in an amount of 40 to 97.5 parts by weight and the
1-butene polymer (b-2) in an amount of 2.5 to 60 parts by weight,
the total amount of said components (b-1) and (b-2) being 100 parts
by weight;
[0028] (3) a laminate wherein the olefin polymer (C') is a
propylene polymer (c-4) and the adhesive resin composition (B') is
a composition comprising a 4-methyl-1-pentene polymer (b-1) and a
1-butene polymer (b-2) and containing the 4-methyl-1-pentene
polymer (b-1) in an amount of 40 to 97.5 parts by weight and the
1-butene polymer (b-2) in an amount of 2.5 to 60 parts by weight,
the total amount of said components (b-1) and (b-2) being 100 parts
by weight;
[0029] (4) a laminate wherein the adhesive resin composition (B')
is a composition comprising a 4-methyl-1-pentene polymer (b-1), a
1-butene polymer (b-2) and a propylene polymer (b-3);
[0030] (5) a laminate wherein the adhesive resin composition (B')
is a composition comprising a 4-methyl-1-pentene polymer (b-1), a
1-butene polymer (b-2) and a propylene polymer (b-3), containing
the 4-methyl-1-pentene polymer (b-1) in an amount of 40 to 97.5
parts by weight and the 1-butene polymer (b-2) in an amount of 2.5
to 60 parts by weight, the total amount of said components (b-1)
and (b-2) being 100 parts by weight, and containing the propylene
polymer (b-3) in an amount of 1 to 100 parts by weight based on 100
parts by weight of the total amount of the components (b-1) and
(b-2);
[0031] (6) a laminate wherein the olefin polymer (C') is a
propylene polymer (c-4) and the adhesive resin composition (Be) is
a composition comprising a 4-methyl-1-pentene polymer (b-1), a
1-butene polymer (b-2) and a propylene polymer (b-3), containing
the 4-methyl-1-pentene polymer (b-1) in an amount of 40 to 97.5
parts by weight and the 1-butene polymer (b-2) in an amount of 2.5
to 60 parts by weight, the total amount of said components (b-1)
and (b-2) being 100 parts by weight, and containing the propylene
polymer (b-3) in an amount of 1 to 100 parts by weight based on 100
parts by weight of the total amount of the components (b-1) and
(b-2); and
[0032] (7) a laminate wherein the olefin polymer (C') is an
ethylene polymer (c-5) and the adhesive resin composition (B') is a
composition comprising a 4-methyl-1-pentene polymer (b-1), a
1-butene polymer (b-2), an ethylene/butene copolymer (b-4), and
optionally, a propylene/butene copolymer (b-5) and containing the
4-methyl-1-pentene polymer (b-1) in an amount of 20 to 60 parts by
weight, the 1-butene polymer (b-2) in an amount of 5 to 40 parts by
weight, the ethylene/butene copolymer (b-4) in an amount of 30 to
60 parts by weight and the propylene/butene copolymer (b-5) in an
amount of 0 to 30 parts by weight, the total amount of said
components (b-1), (b-2), (b-4) and (b-5) being 100 parts by
weight.
[0033] The poly-4-methyl-1-pentene resin laminates mentioned above
are capable of being controlled in the gas permeability such as
oxygen permeability over a wide range of high permeability to low
permeability, and they can be used as materials of packaging media
for keeping freshness of vegetables and fruits.
BEST MODE FOR CARRYING OUT THE INVENTION
[0034] The poly-4-methyl-1-pentene resin laminate of the invention
is described in detail hereinafter.
[0035] The poly-4-methyl-1-pentene resin laminate of the invention
is constituted of a layer made of a 4-methyl-1-pentene polymer (A),
an intermediate layer made of an adhesive resin composition (B) and
a layer made of a propylene polymer composition (C). First, the
resins for forming the layers of the poly-4-methyl-1-pentene resin
laminate are described.
[0036] 4-Methyl-1-pentene Polymer (A)
[0037] Examples of the 4-methyl-1-pentene polymers for use in the
invention include a homopolymer of 4-methyl-1-pentene and
copolymers of 4-methyl-1-pentene and .alpha.-olefins of 2 to 20
carbon atoms other than 4-methyl-1-pentene.
[0038] Examples of the .alpha.-olefins of 2 to 20 carbon atoms
other than 4-methyl-1-pentene include ethylene, propylene,
1-butene, 1-hexene, 1-octene, 1-decene, 1-tetradecene,
1-octadecene, 1-hexadecene, 1-dodecene, 1-tetradecene and
1-eicosene. These .alpha.-olefins can be used singly or in
combination of two or more kinds. Of these, 1-hexene is preferable
in view of copolymerizability.
[0039] In the 4-methyl-1-pentene polymer, it is desirable that the
units derived from 4-methyl-1-pentene are present in amounts of 85
to 100% by mol, preferably 90 to 98% by mol, and the units derived
from other .alpha.-olefins are present in amounts of 0 to 15% by
mol, preferably 2 to 10% by mol. When the content of the units
derived from 4-methyl-1-pentene and the content of the units
derived from other .alpha.-olefins are in the above ranges, the
4-methyl-1-pentene polymer has excellent gas permeability and
mechanical strength.
[0040] The 4-methyl-1-pentene polymer (A) desirably has a melt flow
rate (MFR), as measured under the conditions of a temperature of
260.degree. C. and a load of 5.0 kg in accordance with the method
of ASTM D1238, of 0.1 to 200 g/10 min, preferably 1.0 to 150 g/10
min.
[0041] There is no specific limitation on the process for preparing
the 4-methyl-1-pentene polymer, and the 4-methyl-1-pentene polymer
can be prepared by a conventional process, for example, a process
using a Ziegler Natta catalyst or a cationic polymerization
process.
[0042] Adhesive Resin Composition (B)
[0043] The adhesive resin composition (B) for use in the invention
is a composition consisting of at least two different resins. There
is no specific limitation on the adhesive resin composition, and
any composition is employable as far as the layer of the
4-methyl-1-pentene polymer (A) and the layer of the later-described
propylene polymer composition (C) can be bonded with the adhesive
resin composition, but preferable is a composition comprising a
4-methyl-1-pentene polymer (b-1) and a 1-butene polymer (b-2).
[0044] Examples of the 4-methyl-1-pentene polymers (b-1) employable
herein include those previously described with respect to the
4-methyl-1-pentene polymer (A).
[0045] In the 4-methyl-1-pentene polymer (b-1), however, the
.alpha.-olefin other than 4-methyl-1-pentene is preferably
1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene,
1-hexene or 1-eicosene.
[0046] In the 4-methyl-1-pentene polymer (b-1), the content of the
units derived from 4-methyl-1-pentene is preferably in the range of
80 to 100% by mol, and the content of the units derived from other
.alpha.-olefins is preferably in the range of 0 to 20% by mol. From
the viewpoint of adhesion properties of the resulting adhesive
resin composition, the 4-methyl-1-pentene polymer is preferably a
copolymer, and in this case, the content of the units derived from
4-methyl-1-pentene is preferably in the range of 80 to 99.9% by
mol, and the content of the units derived from other
.alpha.-olefins is preferably in the range of 0.1 to 20% by
mol.
[0047] The 1-butene polymer (b-2) is a homopolymer of 1-butene or a
copolymer of 1-butene and an .alpha.-olefin other than 1-butene
wherein the constituent units derived from 1-butene are contained
in amounts of not less than 60% by weight. Particularly, the
1-butene polymer (b-2) containing constituent units derived from
1-butene in amounts of not less than 80% by weight has excellent
compatibility with the 4-methyl-1-pentene polymer (b-1).
[0048] Examples of the .alpha.-olefins other than 1-butene include
.alpha.-olefins of 2 to 20 carbon atoms other than 1-butene, such
as ethylene, propylene, 1-hexene, 1-octene, 1-decene, 1-tetradecene
and 1-octadecene. These .alpha.-olefins can be used singly or in
combination of two or more kinds. Of these, preferable are ethylene
and propylene.
[0049] The 1-butene polymer (b-2) desirably has MFR, as measured
under the conditions of a temperature of 190.degree. C. and a load
of 2.16 kg in accordance with the method of ASTM D1238, of 0.01 to
100 g/10 min, preferably 0.1 to 50 g/10 min. When MFR of the
1-butene polymer (b-2) is in the above range, the 1-butene polymer
(b-2) shows good blending properties with the 4-methyl-1-pentene
polymer (b-1), and hence the adhesive resin composition (B)
exhibits high adhesion properties.
[0050] It is preferable that the adhesive resin composition (B) for
use in the invention comprises the 4-methyl-1-pentene polymer (b-1)
and the 1-butene polymer (b-2) and contains the 4-methyl-1-pentene
polymer (b-1) in an amount of 40 to 70 parts by weight and the
1-butene polymer (b-2) in an amount of 30 to 60 parts by weight,
the total amount of said components (b-1) and (b-2) being 100 parts
by weight. From the viewpoint of adhesion strength, it is more
preferable that the adhesive resin composition (B) contains the
4-methyl-1-pentene polymer (b-1) in an amount of 45 to 65 parts by
weight and the 1-butene polymer (b-2) in an amount of 35 to 55
parts by weight, the total amount of said components (b-1) and
(b-2) being 100 parts by weight.
[0051] The adhesive resin composition (B) desirably has MFR, as
measured under the conditions of a temperature of 190.degree. C.
and a load of 5.0 kg in accordance with the method of ASTM D1238,
of 0.1 to 200 g/10 min, preferably 1.0 to 100 g/10 min. When MFR of
the adhesive resin composition (B) is in the above range, the
adhesive resin composition (B) exhibits high adhesion properties to
both of the layer of the 4-methyl-1-pentene polymer (A) and the
layer of the propylene polymer composition (C).
[0052] The adhesive resin composition (B) can be prepared by mixing
the 4-methyl-1-pentene polymer (b-1) with the 1-butene polymer
(b-2) by a conventional method and then melt kneading the mixture.
For example, the components (b-1) and (b-2) in given amounts are
mixed by a V-type blender, a ribbon blender, a Henschel mixer, a
tumbling blender or the like. Then, the mixture is melt kneaded by
a single screw extruder, a multiple screw extruder or the like and
granulated, or the mixture is melt kneaded by a kneader, a Banbury
mixer or the like and pulverized.
[0053] The adhesive resin composition (B) may contain various
compounding additives generally added to polyolefins, such as
silane coupling agent, weathering stabilizer, heat stabilizer, slip
agent, nucleating agent and dye.
[0054] Propylene Polymer Composition (C)
[0055] The propylene polymer composition (C) for use in the
invention is a composition comprising a propylene polymer (c-1) and
a 1-butene polymer (c-2) or a composition comprising a propylene
polymer (c-1) and a propylene/ethylene copolymer (c-3).
[0056] Examples of the propylene polymers (c-1) include:
[0057] a homopolymer of propylene,
[0058] a propylene random copolymer (e.g., a propylene/ethylene
random copolymer, a propylene/ethylene/1-butene random copolymer or
a propylene/1-butene random copolymer) containing constituent units
derived from propylene in amounts of not less than 90% by mol,
preferably not less than 95% by mol, and
[0059] a propylene/ethylene block copolymer containing constituent
units derived from ethylene in amounts of 5 to 30% by mol.
[0060] The propylene polymer (c-1) desirably has MFR, as measured
under the conditions of a temperature of 230 oC and a load of 2.16
kg in accordance with the method of ASTM D1238, of 0.01 to 100 g/10
min, preferably 0.1 to 50 g/10 min. When MFR of the propylene
polymer (c-1) is in the above range, the propylene polymer (c-1)
shows good blending properties with the 1-butene polymer (c-2) or
the propylene/ethylene copolymer (c-3).
[0061] The 1-butene polymer (c-2) is a homopolymer of 1-butene or a
copolymer of 1-butene and an .alpha.-olefin other than 1-butene
wherein the constituent units derived from 1-butene are contained
in amounts of not less than 60% by weight. Particularly, the
1-butene polymer (c-2) containing constituent units derived from
1-butene in amounts of not less than 80% by weight has excellent
compatibility with the propylene polymer (c-1).
[0062] Examples of the .alpha.-olefins other than 1-butene include
.alpha.-olefins of 2 to 20 carbon atoms other than 1-butene, such
as ethylene, propylene, 1-hexene, 1-octene, 1-decene, 1-tetradecene
and 1-octadecene. These .alpha.-olefins can be used singly or in
combination of two or more kinds. Of these, preferable are ethylene
and propylene.
[0063] The 1-butene polymer (c-2) desirably has MFR, as measured
under the conditions of a temperature of 190.degree. C. and a load
of 2.16 kg in accordance with the method of ASTM D1238, of 0.01 to
100 g/10 min, preferably 0.1 to 50 g/10 min. When MFR of the
1-butene polymer (c-2) is in the above range, the 1-butene polymer
(c-2) shows good blending properties with the propylene polymer
(c-1).
[0064] The propylene/ethylene copolymer (c-3) is a
propylene/ethylene random copolymer containing constituent units
derived from propylene in amounts of 50 to 90% by weight.
Especially when the constituent units derived from propylene are
contained in amounts of 60 to 85% by weight, the resin laminate
exhibits excellent mechanical strength. The propylene/ethylene
copolymer (c-3) may further contain constituent units derived from
other olefins such as olefins of 4 to 20 carbon atoms.
[0065] The propylene/ethylene copolymer (c-3) desirably has MFR, as
measured under the conditions of a temperature of 230.degree. C.
and a load of 2.16 kg in accordance with the method of ASTM D1238,
of 0.1 to 200 g/10 min, preferably 1.0 to 100 g/10 min. When MFR of
the propylene/ethylene copolymer (c-3) is in the above range, the
propylene/ethylene copolymer (c-3) shows good blending properties
with the propylene polymer (c-1).
[0066] It is preferable that the propylene polymer composition (C)
for use in the invention comprises the propylene polymer (c-1) and
the 1-butene polymer (c-2) and contains the propylene polymer (c-1)
in an amount of 60 to 90 parts by weight and the 1-butene polymer
(c-2) in an amount of 10 to 40 parts by weight, the total amount of
said components (c-1) and (c-2) being 100 parts by weight.
[0067] In this case, it is more preferable in view of balance
between heat sealing strength and gas permeability that the
propylene polymer composition (C) contains the propylene polymer
(c-1) in an amount of 60 to 80 parts by weight and the 1-butene
polymer (c-2) in an amount of 20 to 40 parts by weight, the total
amount of said components (c-1) and (c-2) being 100 parts by
weight.
[0068] It is also preferable that the propylene polymer composition
(C) for use in the invention comprises the propylene polymer (c-1)
and the propylene/ethylene copolymer (c-3) and contains the
propylene polymer (c-1) in an amount of 60 to 90 parts by weight
and the propylene/ethylene copolymer (c-3) in an amount of 10 to 40
parts by weight, the total amount of said components (c-1) and
(c-3) being 100 parts by weight.
[0069] In this case, it is more preferable in view of balance
between heat sealing strength and gas permeability that the
propylene polymer composition (C) contains the propylene polymer
(c-1) in an amount of 60 to 80 parts by weight and the
propylene/ethylene copolymer (c-3) in an amount of 20 to 40 parts
by weight, the total amount of said components (c-1) and (c-3)
being 100 parts by weight.
[0070] The propylene polymer composition (C) can be prepared by
mixing the propylene polymer (c-1) with the 1-butene polymer (c-2)
or mixing the propylene polymer (c-1) with the propylene/ethylene
copolymer (c-3) by a conventional method and then melt kneading the
mixture. For example, the components (c-1) and (c-2) or the
components (c-1) and the (c-3) in given amounts are mixed by a
V-type blender, a ribbon blender, a Henschel mixer, a tumbling
blender or the like. Then, the mixture is melt kneaded by a single
screw extruder, a multiple screw extruder or the like and
granulated, or the mixture is melt kneaded by a kneader, a Banbury
mixer or the like and pulverized.
[0071] The propylene polymer composition (C) may contain various
compounding additives generally added to polyolefins, such as
silane coupling agent, weathering stabilizer, heat stabilizer, slip
agent, nucleating agent and dye.
[0072] The poly-4-methyl-1-pentene resin laminate of the invention
is constituted of a layer made of the 4-methyl-1-pentene polymer
(A), an intermediate layer made of the adhesive resin composition
(B) and a layer made of the propylene polymer composition (C).
[0073] Although there is no specific limitation on the thickness
ratio between the layers for forming the laminate, the thickness
ratio between the layer of the 4-methyl-1-pentene polymer (A), the
intermediate layer of the adhesive resin composition (B) and the
layer of the propylene polymer composition (C) is usually
1-100:1-100:1-100, preferably 50-100:1-50:1-50.
[0074] Likewise, there is no specific limitation on the thickness
of the laminate, and the thickness thereof can be appropriately
determined according to the shape, size and use application of the
laminate. The thickness of the laminate is in the range of usually
about 0.01 to 2.0 mm, preferably about 0.02 to 0.5 mm.
[0075] The poly-4-methyl-1-pentene resin laminate of the invention
can be prepared by, for example, co-extrusion molding of the
4-methyl-1-pentene polymer (A), the adhesive resin composition (B)
and the propylene polymer composition (C), or press molding of
sheets or films produced in advance from the resins (compositions)
by press molding, extrusion molding or the like.
[0076] The poly-4-methyl-1-pentene resin laminate has excellent gas
permeability, heat sealing properties and blocking resistance, so
that it can be favorably used for freshness-keeping packaging media
and culture containers requiring oxygen permeability, resistance to
heat of heat sterilization and heat sealing properties. Further,
the poly-4-methyl-1-pentene resin laminate is free from blocking
even when exposed to a temperature of about 120.degree. C., so that
it can be subjected to heat sterilization.
[0077] Next, the other embodiment of the poly-4-methyl-1-pentene
resin laminate of the invention is described.
[0078] The other embodiment of the poly-4-methyl-1-pentene resin
laminate of the invention is constituted of:
[0079] (I) a layer made of a 4-methyl-1-pentene polymer (A'),
[0080] (II) an intermediate layer made of an adhesive resin
composition (B'), and
[0081] (III) a layer made of an olefin polymer (C').
[0082] First, the resins for forming the layers of the
poly-4-methyl-1-pentene resin laminate of the invention are
described.
[0083] 4-Methyl-1-pentene Polymer (A')
[0084] Examples of the 4-methyl-1-pentene polymers include a
homopolymer of 4-methyl-1-pentene and copolymers of
4-methyl-1-pentene and .alpha.-olefins of 2 to 24 carbon atoms
other than 4-methyl-1-pentene.
[0085] Examples of the .alpha.-olefins of 2 to 24 carbon atoms
other than 4-methyl-1-pentene include ethylene, propylene,
1-butene, 1-hexene, 1-octene, 1-decene, 1-tetradecene,
1-octadecene, 1-hexadecene, 1-dodecene and 1-tetradecene. These
.alpha.-olefins can be used singly or in combination of two or more
kinds. Of these, 1-hexene is preferable in view of
copolymerizability.
[0086] In the 4-methyl-1-pentene polymer, it is desirable that the
units derived from 4-methyl-1-pentene are present in amounts of 80
to 100% by mol, preferably 85 to 98% by mol, and the units derived
from other .alpha.-olefins are present in amounts of 0 to 20% by
mol, preferably 2 to 15% by mol. When the content of the units
derived from 4-methyl-1-pentene and the content of the units
derived from other .alpha.-olefins are in the above ranges, the
4-methyl-1-pentene polymer has excellent gas permeability and
mechanical strength.
[0087] The 4-methyl-1-pentene polymer (A') desirably has MFR, as
measured under the conditions of a temperature of 260.degree. C.
and a load of 5.0 kg in accordance with the method of ASTM D1238,
of 0.1 to 200 g/10 min, preferably 1.0 to 150 g/10 min.
[0088] There is no specific limitation on the process for preparing
the 4-methyl-1-pentene polymer, and the 4-methyl-1-pentene polymer
can be prepared by a conventional process, for example, a process
using a Ziegler Natta catalyst or a cationic polymerization
process.
[0089] The 4-methyl-1-pentene polymer (A') may be graft modified
with modification monomers. The modified 4-methyl-1-pentene polymer
is preferable because films having excellent adhesion properties
and sheet-forming properties can be obtained therefrom.
[0090] Examples of the modification monomers include unsaturated
carboxylic acids, such as (meth)acrylic acid, maleic acid, fumaric
acid, tetrahydrofumaric acid, itaconic acid, citraconic acid,
crotonic acid, isocrotonic acid and
endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (Nadic
acids); and derivatives of these acids, such as acid halides, acid
amides, acid imides, acid anhydrides and esters thereof. Particular
examples of the derivatives include alkyl esters of (meth)acrylic
acid, such as malenyl chloride, maleimide, maleic anhydride,
citraconic anhydride, dimethyl maleate, glycidyl maleate, methyl
(meth)acrylate and ethyl (meth)acrylate. These modification
monomers can be used singly or in combination of two or more kinds.
Of these, preferable are unsaturated dicarboxylic acids and
anhydrides thereof. Particularly preferable are maleic acid, Nadic
acids and anhydrides thereof.
[0091] The content (graft quantity) of the modification monomer in
the modified 4-methyl-1-pentene polymer is in the range of usually
0.1 to 20% by weight, preferably 0.5 to 5% by weight.
[0092] The 4-methyl-1-pentene polymer can be modified by, for
example, heating the 4-methyl-1-pentene polymer and the
modification monomer to a temperature of 100 to 300.degree. C.,
preferably 125 to 250.degree. C., in a solvent in the presence of a
polymerization initiator, or kneading the methyl-1-pentene polymer
with the modification monomer at a temperature of 235 to
250.degree. C. by an extruder in the presence of a polymerization
initiator using no solvent.
[0093] The polymerization initiator is, for example, an organic
peroxide. Particular examples of the organic peroxides include
alkyl peroxides, such as di-t-butyl peroxide,
2,5-dimethyl-2,5-di-t-butylperoxy-hexyne-3 and diisopropyl
peroxide; aryl peroxides, such as dicumyl peroxide; acyl peroxides,
such as lauroyl peroxide; aroyl peroxides, such as dibenzoyl
peroxide; ketone peroxides, such as methyl ethyl ketone peroxide
and cyclohexanone peroxide; hydroperoxides, such as t-butyl
peroxide and cumene hydroperoxide; peroxy carbons; and peroxy
carboxylates. These polymerization initiators can be used singly or
in combination of two or more kinds. The polymerization initiator
is used in an amount of usually about 0.01 to 1 part by weight
based on 100 parts by weight of the 4-methyl-1-pentene polymer.
[0094] Examples of the solvents include aliphatic hydrocarbons,
such as hexane, heptane, octane, decane, dodecane and tetradecane;
alicyclic hydrocarbons, such as methylcyclopentane, cyclohexane,
methylcyclohexane, cyclooctane and cyclodecane; aromatic
hydrocarbons, such as benzene, toluene, xylene, ethylbenzene,
cumene, ethyltoluene, trimethylbenzene, cymene and
diisopropylbenzene; halogenated hydrocarbons, such as
chlorobenzene, bromobenzene, o-dichlorobenzene, carbon
tetrachloride, trichloroethane, trichloroethylene,
tetrachloroethane and tetrachloroethylene; and kerosine that is a
mixture of aliphatic hydrocarbons. These solvents can be used
singly or in combination of two or more kinds. The solvent is used
in an amount of usually about 100 to 5,000 parts by weight based on
100 parts by weight of the 4-methyl-1-pentene polymer.
[0095] Adhesive Resin Composition (B')
[0096] The adhesive resin composition (B') for use in the invention
is a composition consisting of at least two different resins. There
is no specific limitation on the adhesive resin composition, and
any composition is employable as far as the layer of the
4-methyl-1-pentene polymer (A') and the layer of the
later-described olefin polymer (C') can be bonded with the adhesive
resin composition (B'), but preferable is any of the following
resin compositions (I) to (III).
[0097] (I) A resin composition comprising a 4-methyl-1-pentene
polymer (b-1) and a 1-butene polymer (b-2).
[0098] It is preferable that the resin composition (I) contains the
4-methyl-1-pentene polymer (b-1) in an amount of 40 to 97.5 parts
by weight and the 1-butene polymer (b-2) in an amount of 2.5 to 60
parts by weight, the total amount of said components (b-1) and
(b-2) being 100 parts by weight.
[0099] (II) A resin composition comprising a 4-methyl-1-pentene
polymer (b-1), 1-butene polymer (b-2) and a propylene polymer
(b-3).
[0100] It is preferable that the resin composition (II) contains
the 4-methyl-1-pentene polymer (b-1) in an amount of 40 to 97.5
parts by weight and the 1-butene polymer (b-2) in an amount of 2.5
to 60 parts by weight, the total amount of said components (b-1)
and (b-2) being 100 parts by weight, and contains the propylene
polymer (b-3) in an amount of 1 to 100 parts by weight based on 100
parts by weight of the total amount of the components (b-1) and
(b-2).
[0101] When the adhesive resin composition (B') is the resin
composition (I) or (II), the layer made of the olefin polymer (C')
is preferably a layer made of a propylene polymer (c-4).
[0102] (III) A resin composition comprising a 4-methyl-1-pentene
polymer (b-1), a 1-butene polymer (b-2), an ethylene/butene
copolymer (b-4), and optionally, a propylene/butene copolymer
(b-5).
[0103] It is preferable that the resin composition (III) contains
the 4-methyl-1-pentene polymer (b-1) in an amount of 20 to 60 parts
by weight, the 1-butene polymer (b-2) in an amount of 5 to 40 parts
by weight, the ethylene/butene copolymer (b-4) in an amount of 30
to 60 parts by weight and the propylene/butene copolymer (b-5) in
an amount of 0 to 30 parts by weight, the total amount of said
components (b-1), (b-2), (b-4) and (b-5) being 100 parts by
weight.
[0104] When the adhesive resin composition (B') is the resin
composition (III), the layer made of the olefin polymer (C') is
preferably a layer made of an ethylene polymer (c-5).
[0105] Examples of the 4-methyl-1-pentene polymers (b-1) employable
for forming the resin compositions (I) to
[0106] (III) include those previously described with respect to the
4-methyl-1-pentene polymer (b-1) for forming the adhesive resin
composition (B).
[0107] Examples of the 1-butene polymers (b-2) employable for
forming the resin compositions (I) and (II) include those
previously described with respect to the 1-butene polymer (b-2) for
forming the adhesive resin composition (B).
[0108] Examples of the propylene polymers (b-3) employable for
forming the resin composition (II) include those previously
described with respect to the propylene polymer (c-1) for forming
the propylene polymer composition (C).
[0109] The propylene polymer (b-3) desirably has MFR, as measured
under the conditions of a temperature of 230 oC and a load of 2.16
kg in accordance with the method of ASTM D1238, of 0.01 to 100 g/10
min, preferably 0.1 to 50 g/10 min. When MFR of the propylene
polymer (b-3) is in the above range, the propylene polymer (b-3)
shows good blending properties with other resins for forming the
resin composition.
[0110] The ethylene/butene copolymer (b-4) for forming the resin
composition (III) is a copolymer containing constituent units
derived from ethylene in amounts of not less than 60% by weight,
preferably not less than 80% by weight.
[0111] The ethylene/butene copolymer (b-4) desirably has MFR, as
measured under the conditions of a temperature of 190.degree. C.
and a load of 2.16 kg in accordance with the method of ASTM D1238,
of 0.01 to 100 g/10 min, preferably 0.1 to 50 g/10 min. When MFR of
the ethylene/butene copolymer (b-4) is in the above range, the
copolymer (b-4) shows good blending properties with other resins
for forming the resin composition, and hence the adhesive resin
composition (Bs) exhibits high adhesion properties.
[0112] The propylene/butene copolymer (b-S) for forming the resin
composition (III) is a copolymer containing constituent units
derived from propylene in amounts of not less than 60% by weight,
preferably not less than 80% by weight.
[0113] The propylene/butene copolymer (b-S) desirably has MFR, as
measured under the conditions of a temperature of 190.degree. C.
and a load of 2.16 kg in accordance with the method of ASTM D1238,
of 0.01 to 100 g/10 min, preferably 0.1 to 50 g/10 min. When MFR of
the propylene/butene copolymer (b-5) is in the above range, the
copolymer (b-S) shows good blending properties with other resins
for forming the resin composition, and hence the adhesive resin
composition (B') exhibits high adhesion properties.
[0114] The resin compositions (I) to (III) can be prepared by melt
kneading the 4-methyl-1-pentene polymer (b-1) with other resins by
a conventional method. For example, the 4-methyl-1-pentene polymer
(b-1) and other resins in given amounts are mixed by a V-type
blender, a ribbon blender, a Henschel mixer, a tumbling blender or
the like. Then, the mixture is melt kneaded by a single screw
extruder, a multiple screw extruder or the like and granulated, or
the mixture is melt kneaded by a kneader, a Banbury mixer or the
like and pulverized.
[0115] The intermediate layer made of any of the above resin
compositions can firmly adhere to the surface layer made of the
4-methyl-1-pentene polymer (A') or the olefin polymer (C').
[0116] Olefin Polymer (C')
[0117] Examples of the olefin polymers (C') include an ethylene
polymer (c-5), such as polyethylene, an ethylene/.alpha.-olefin
copolymer or an ethylene/.alpha.-olefin/nonconjugated polyene
copolymer, a propylene polymer (c-4), such as polypropylene, a
propylene/.alpha.-olefin copolymer, block polypropylene or random
polypropylene, and a butene polymer, such as poly-1-butene or a
1-butene copolymer.
[0118] The propylene polymer (c-4) is particularly preferably
polypropylene, a copolymer of propylene and not more than 30% by
mol of ethylene, or a copolymer of propylene and not more than 30%
by mol of an .alpha.-olefin of 4 to 12 carbon atoms. The copolymers
may be each a block copolymer or a random copolymer. The
crystallinity of the propylene polymer, as measured by X-ray
diffractometry, is preferably not less than 30%.
[0119] The ethylene polymer (c-5) is particularly preferably
polyethylene, or a copolymer of ethylene and not more than 30% by
mol of an .alpha.-olefin of 3 or more carbon atoms. The ethylene
polymer includes linear low-density polyethylene, high-density
polyethylene and high-pressure low-density polyethylene. The
crystallinity of the ethylene polymer, as measured by X-ray
diffractometry, is preferably not less than 30%.
[0120] Compounding Additives
[0121] The resins for forming the poly-4-methyl-1-pentene resin
laminate of the invention may contain an inorganic filler. Examples
of the inorganic fillers include powder fillers, such as natural
silicic acid or silicates (specifically, powdered talc, kaolinite,
calcined clay, pyrophyllite, sericite and wollastonite), carbonates
(specifically, precipitated calcium carbonate, heavy calcium
carbonate and magnesium carbonate), hydroxides, (specifically,
aluminum hydroxide and magnesium hydroxide), oxides (specifically,
zinc oxide, zinc white and magnesium oxide), and synthetic silicic
acid or silicates (specifically, hydrated calcium silicate,
hydrated aluminum silicate, hydrated silicic acid and silicic
anhydride); flaky fillers, such as mica; fibrous fillers, such as
basic magnesium sulfate whisker, calcium titanate whisker, aluminum
borate whisker, sepiolite, PMF (processed mineral fiber),
xonotlite, potassium titanate and ellestadite; and balloon fillers,
such as glass balloon and fly ash balloon.
[0122] In addition to the inorganic fillers, organic fillers such
as high styrenes, lignins and reclaimed rubber may be used.
[0123] As the inorganic filler, powdered talc is particularly
preferable, and it is desirable to use powdered talc having an
average particle diameter of 0.2 to 3 .mu.m, preferably 0.2 to 2.5
.mu.m. In the powdered talc, the content of particles having
diameters of not less than 5 .mu.m is desirably not more than 10%
by weight, preferably not more than 8% by weight. The particle
diameter of the powdered talc can be measured by a liquid phase
precipitation method.
[0124] As the powdered talc, talc having an average aspect ratio
(aspect ratio: ratio of the longitudinal or lateral length to the
thickness) of not less than 3, particularly not less than 4, is
preferably employed.
[0125] The inorganic filler, particularly powdered talc, may be
untreated one or one having been previously subjected to a surface
treatment. Examples of the surface treatments include chemical and
physical treatments using agents such as silane coupling agents,
higher fatty acids, metallic salts of fatty acids, unsaturated
organic acids, organic titanates, resin acids and polyethylene
glycol.
[0126] The resins for forming the poly-4-methyl-1-pentene resin
laminate of the invention may further contain compounding additives
in amounts not detrimental to the objects of the invention.
Examples of such additives include antioxidants, such as phenolic
antioxidants, sulfur type antioxidants and phosphorus type
antioxidants, nucleating agents, such as aluminum salts of aromatic
carboxylic acids, salts of aromatic phosphoric esters and
dibenzylidenesorbitol, heat stabilizers, ultraviolet light
absorbers, lubricants, anti-blocking agents, antistatic agents,
flame retardants, pigments, dyes, dispersants, copper inhibitors,
neutralizing agents, foaming agents, plasticizers, bubble
inhibitors, crosslinking agents, peroxides, flow improvers, light
stabilizers, weld strength improvers, and anti-fogging agents.
[0127] Examples of the phenolic antioxidants include phenols, such
as 2,6-di-tert-butyl-p-cresol and
stearyl(3,3-dimethyl-4-hydroxybenzyl) thioglycolate; and carbonic
acid oligoesters of polyphenols, such as carbonic acid oligoester
of 4,41-butylidenebis(2-tert-butyl-5-methylpheno- l) (degree of
polymerization: 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.).
[0128] An example of the sulfur type antioxidant is dialkyl
thiodipropionate.
[0129] An example of the phosphorus type antioxidant is triphenyl
phosphite.
[0130] A complex represented by the formula
M.sub.xAl.sub.y(OH).sub.2x+3y-- 2z(A).sub.z.aH.sub.2O (wherein M is
Mg, Ca or Zn, A is an anion other than a hydroxyl group, x, y and z
are each a positive number, and a is 0 or a positive number) can be
added as, for example, a hydrochloric acid absorbent.
[0131] An example of the light stabilizer is
2-hydroxy-4-methoxybenzopheno- ne.
[0132] Examples of the lubricants include paraffin wax,
polyethylene wax and calcium stearate.
[0133] These additives can be used in amounts of 0.0001 to 10 parts
by weight based on 100 parts by weight of the resins for forming
the poly-4-methyl-1-pentene resin laminate. When the above
additives are added to the resins for forming the
poly-4-methyl-1-pentene resin laminate, a laminate further improved
in property balance, endurance, paintability, printability, scratch
resistance and moldability can be obtained.
[0134] The above-mentioned various compounding additives can be
incorporated into the resins for forming the
poly-4-methyl-1-pentene resin laminate by introducing the additives
simultaneously or successively into a Henschel mixer, a V-type
blender, a tumbling blender, a ribbon blender or the like, mixing
them with the resins and then melt kneading the mixture by a single
screw extruder, a multiple screw extruder, a kneader, a Banbury
mixer or the like.
[0135] A kneading device exhibiting excellent kneading performance,
such as a multiple screw extruder, a kneader or a Banbury mixer, is
preferably employed because the additives can be more homogeneously
dispersed.
[0136] Laminate
[0137] The poly-4-methyl-1-pentene resin laminate of the invention
is constituted of a layer of the 4-methyl-1-pentene polymer (A'),
an intermediate layer of the adhesive resin composition (B') and a
layer of the olefin polymer (C').
[0138] There is no specific limitation on the thickness of each
layer for forming the laminate, and the thickness thereof is
appropriately determined according to the desired oxygen
permeability, carbon dioxide permeability and water vapor
permeability.
[0139] The thickness ratio between the layer of the
4-methyl-1-pentene polymer (A'), the intermediate layer of the
adhesive resin composition (B') and the layer of the olefin polymer
(C') is usually 1-100:1-100:1-100, preferably 50-100:1-50:1-50.
[0140] Likewise, there is no specific limitation on the thickness
of the laminate, and the thickness thereof can be appropriately
determined according to the shape, size and use application of the
laminate. The thickness of the laminate is in the range of usually
about 0.01 to 3 mm, preferably about 0.02 to 0.5 mm.
[0141] The poly-4-methyl-1-pentene resin laminate of the invention
can be prepared by, for example, co-extrusion molding (e.g., T-die
casting or water cooling inflation) of the 4-methyl-1-pentene
polymer (A'), the adhesive resin composition (B') and the olefin
polymer (C'), or press molding of sheets or films produced in
advance from the resins by press molding, extrusion molding or the
like.
[0142] The 4-methyl-1-pentene polymer is a resin having an
extremely high gas permeability, so that if the 4-methyl-1-pentene
polymer layer is laminated to a layer of the olefin polymer having
a low gas permeability and the thickness of each layer is adjusted,
the gas permeability such as oxygen permeability, carbon dioxide
permeability and water vapor permeability of the resulting laminate
can be controlled over a wider range than before. Further, by the
use of the olefin polymer having a low melting point as the surface
layer, the laminate can be imparted with heat sealing
properties.
[0143] Packaging Medium
[0144] The packaging medium according to the invention comprises
the poly-4-methyl-1-pentene resin laminate mentioned above, and can
take various forms such as film, sheet, bag, bottle, can, box and
tube. When the packaging medium is a film or a bag, the thickness
of the packaging medium is in the range of usually 20 to 100 .mu.m,
preferably 30 to 50 .mu.m. When the packaging medium is a bottle, a
can, a box or a tubular container, the thickness of the packaging
medium is in the range of usually 0.2 to 3 mm, preferably 0.5 to 2
mm. In order to control the gas permeability, the thickness of the
packaging medium can be partly changed.
[0145] A part of a container can be formed from a film made of the
poly-4-methyl-1-pentene resin laminate.
[0146] The packaging medium of the invention can be prepared by a
conventional method without specific limitation.
[0147] In the method for keeping freshness of vegetables and fruits
according to the invention, the vegetables and fruits are wrapped
with the abvoe packaging medium. Examples of vegetables and fruits
whose freshness can be kept by the method of the invention
include:
[0148] fruits, such as apricot, avocado, fig, strawberry,
blackberry, blueberry, cranberry, dewberry, gooseberry,
loganblackberry, raspberry (black), raspberry (red), persimmon,
chestnut, coconut, cherry, watermelon, pear, pineapple (green),
pineapple (full-ripe), banana, papaya, plum, quince, mango, melon
(cantaloupe), melon (honeydew), peach and apple; and
[0149] vegetables, such as asparagus, kidney bean, lima bean, okra,
turnip, autumn squash, cauliflower, cabbage, Brussels sprouts,
cucumber, green peas, kale, sweet potato, potato, sweet corn, pop
corn, celery, radish, onion, pepper (green pepper), pepper (red
pepper, dried), tomato, egg plant, garlic, carrot (foliaged),
carrot (root), spinach, broccoli, mushroom, rhubarb, lettuce and
vegetable seeds.
[0150] The method for keeping freshness according to the invention
can keep freshness of cut vegetables, and examples of the cut
vegetables include carrot (dice, random cut, ginkgo leaf shape,
stick, coin cut, long thin strip), potato (dice, random cut, long
thin strip, stick), cabbage (square cut, long thin strip), radish
(ginkgo leaf shape, stick, long thin strip), onion (dice, random
cut, round slice, slice), cucumber (stick, slice), celery (stick),
sweet pepper (half cut, 1/4 cut, round slice, long thin strip),
lettuce (square cut, 1/4 cut, slice), spinach (boiled, fresh),
asparagus (boiled, fresh), broad bean (hulled), green peas
(hulled), green soybean (boiled), spring onion (slice for relish,
oblique cut, long thin strip), Nanking shallot (for relish), sunny
lettuce (leaf), parsley (leaf), egg plant (1/2 cut, 1/4 cut), sweet
potato (slice), pumpkin (slice, random cut), red carrot (round
slice), red cabbage (long thin strips), green pepper, kidney bean,
lotus, burdock (round slice, long thin strip), and mixtures
thereof.
[0151] The poly-4-methyl-1-pentene resin laminate according the
invention can control gas permeability over a wide range of high
permeability to low permeability.
[0152] By the use of the packaging medium comprising the
poly-4-methyl-1-pentene resin laminate according to the invention,
freshness of vegetables and fruits can be kept for a long period of
time.
EXAMPLE
[0153] The present invention is further described with reference to
the following examples, but it should be construed that the
invention is in no way limited to those examples.
[0154] In the examples, properties were measured in the following
manner.
[0155] Melt Flow Rate (MFR)
[0156] The melt flow rate of a 4-methyl-1-pentene polymer was
measured under the conditions of a temperature of 260.degree. C.
and a load of 5 kg, the melt flow rate of a propylene polymer was
measured under the conditions of a temperature of 230.degree. C.
and a load of 2.16 kg, and the melt flow rate of other resins was
measured under the conditions of a temperature of 190.degree. C.
and a load of 2.16 kg, in accordance with the method of ASTM
D1238.
[0157] Oxygen Permeability
[0158] The oxygen permeability was measured By a measuring device
of OX-TRAN (manufactured by Modern Control Co.) under the
conditions of a temperature of 23.degree. C. and a humidity of 0%.
Specifically, an oxygen permeability V (cc/m.sup.2.multidot.24
hr.multidot.atm) of a (three-layer) film was measured, and using
the measured value, an oxygen permeability constant k
(cc.multidot.mm/m.sup.2.multidot.24 hr.multidot.atm), that is an
oxygen permeability per 1 mm (thickness) of the (three-layer) film,
was calculated.
[0159] Between V and k, there is a relationship represented by the
formula k=d.multidot.V/1,000 (wherein d is a thickness (.mu.m) of
the film).
[0160] Measurement of Adhesion Strength
[0161] A three-layer film was subjected to a T-peel test under the
conditions of a peel rate of 300 mm/min, a peel width of 15 mm and
a temperature of 23.degree. C.
[0162] Freshness Keeping Test
[0163] Changes in appearance and color of vegetables and fruits
were visually observed every day at a temperature of 25.degree. C.,
and freshness of the vegetables and fruits was evaluated based on
the following criteria.
[0164] AA: good
[0165] BB: slightly bad
[0166] CC: bad
Example 1
[0167] A 4-methyl-1-pentene polymer (A-1) (trade name: TPX RT18,
available from Mitsui Petrochemical Industries, Ltd.) having a
melting point of 237.degree. C., MFR of 25 g/10 min and a density
of 0.835 g/cm.sup.3 (ASTM D 1505) was used as the
4-methyl-1-pentene polymer.
[0168] An adhesive resin composition (B-1) obtained by mixing 60
parts by weight of a 4-methyl-1-pentene polymer (1-octadecene
content: 6% by weight, MFR: 3.0 g/10 min), 40 parts by weight of a
1-butene polymer (ethylene content: 5% by weight, MFR: 2.5 g/10
min), 0.10 part by weight of
3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1--
dimethylethyl]2,4,8,10-tetrakis-spiro[5,5]undecane (trade name:
Sumilizer GA80, available from Sumitomo Chemical Co. Ltd.) as a
stabilizer, 0.20 part by weight of
penta(erythrityl-tetra-.beta.-mercaptonyl)propionate (trade name:
Sienox 412S, available from Sipro Kasei K.K.) and 0.03 part by
weight of calcium stearate (available from Sankyo Yukigosei K.K.)
by a Henschel mixer at a low rotational speed for 3 minutes and
extruding the mixture by a twin-screw extruder at a temperature of
280.degree. C. was used as the adhesive resin composition.
[0169] A propylene polymer composition (C-1) obtained by extruding
a mixture of 60 parts by weight of polypropylene (trade name:
F-600, available from Grand Polymer K.K.) having MFR of 10 g/10 min
and a density of 0.91 g/cm.sup.3 and 40 parts by weight of a
1-butene polymer (trade name: Viewron M3080, available from Mitsui
Petrochemical Industries, Ltd.) having MFR of 0.2 g/10 min and a
density of 0.890 g/cm.sup.3 by a twin-screw extruder at a
temperature of 280.degree. C. was used as the propylene polymer
composition.
[0170] Production of Three-layer Film
[0171] A three-layer film (poly-4-methyl-1-pentene resin laminate)
consisting of a layer of the 4-methyl-1-pentene polymer (A-1), an
intermediate layer of the adhesive resin composition (B-1) and a
layer of the propylene polymer composition (C-1) was produced by a
co-extrusion T-die extruder. The thickness ratio between the layers
of the film was 80 .mu.m/10 .mu.m/10 .mu.m ((A-1)/(B-1)/(C-1)).
Example 2
[0172] A three-layer film was produced in the same manner as in
Example 1, except that a propylene polymer composition (C-2)
obtained by extruding a mixture of 80 parts by weight of
polypropylene (trade name: F-600, available from Grand Polymer
K.K.) having MFR of 10 g/10 min and a density of 0.91 g/cm.sup.3
and 20 parts by weight of a 1-butene polymer (trade name: Viewron
M3080, available from Mitsui Petrochemical Industries, Ltd.) having
MFR of 0.2 g/10 min and a density of 0.890 g/cm.sup.3 by a
twin-screw extruder at a temperature of 280.degree. C. was used in
place of the propylene polymer composition (C-1). The thickness
ratio between the layers of the film was 80 .mu.m/10 .mu.m/10 .mu.m
((A-1)/(B-1)/(C-2)).
Example 3
[0173] A three-layer film was produced in the same manner as in
Example 1, except that a propylene polymer composition (C-3)
obtained by extruding a mixture of 60 parts by weight of
polypropylene (trade name: F-600, available from Grand Polymer
K.K.) having MFR of 10 g/10 min and a density of 0.91 g/cm.sup.3
and 40 parts by weight of a propylene/ethylene copolymer having MFR
of 0.2 g/10 min and a density of 0.890 g/cm.sup.3 by a twin-screw
extruder at a temperature of 280.degree. C. was used in place of
the propylene polymer composition (C-1). The thickness ratio
between the layers of the film was 80 .mu.m/10 .mu.m/10 .mu.m
((A-1)/(B-1)/(C-3)).
Example 4
[0174] A three-layer film was produced in the same manner as in
Example 1, except that a propylene polymer composition (C-4)
obtained by extruding a mixture of 80 parts by weight of
polypropylene (trade name: F-600, available from Grand Polymer
K.K.) having MFR of 10 g/10 min and a density of 0.91 g/cm.sup.3
and 20 parts by weight of a propylene/ethylene copolymer having MFR
of 0.2 g/10 min and a density of 0.890 g/cm.sup.3 by a twin-screw
extruder at a temperature of 280.degree. C. was used in place of
the propylene polymer composition (C-1). The thickness ratio
between the layers of the film was 80 .mu.m/10 .mu.m/10 .mu.m
((A-1)/(B-1)/(C-4)).
Comparative Example 1
[0175] A three-layer film was produced in the same manner as in
Example 1, except that polypropylene (C-5) (trade name: F-600,
available from Grand Polymer K.K.) having MFR of 10 g/10 min and a
density of 0.91 g/cm.sup.3 was used singly in place of the
propylene polymer composition (C-1). The thickness ratio between
the layers of the film was 80 .mu.m/10 .mu.m/10 .mu.m
((A-1)/(B-1)/(C-5)).
Comparative Example 2
[0176] A three-layer film was produced in the same manner as in
Example 1, except that a propylene polymer composition (C-6)
obtained by extruding a mixture of 40 parts by weight of
polypropylene (trade name: F-600, available from Grand Polymer
K.K.) having MFR of 10 g/10 min and a density of 0.91 g/cm.sup.3
and 60 parts by weight of a propylene/ethylene copolymer having MFR
of 0.2 g/10 min and a density of 0.890 g/cm.sup.3 by a twin-screw
extruder at a temperature of 280.degree. C. was used in place of
the propylene polymer composition (C-1). The thickness ratio
between the layers of the film was 80 .mu.m/10 .mu.m/10 .mu.m
((A-1)/(B-1)/(C-6)).
Comparative Example 3
[0177] A three-layer film was produced in the same manner as in
Example 1, except that a propylene polymer composition (C-7)
obtained by extruding a mixture of 40 parts by weight of
polypropylene (trade name: F-600, available from Grand Polymer
K.K.) having MFR of 10 g/10 min and a density of 0.91 g/cm.sup.3
and 60 parts by weight of a 1-butene polymer having MFR of 0.2 g/10
min and a density of 0.890 g/cm.sup.3 by a twin-screw extruder at a
temperature of 280.degree. C. was used in place of the propylene
polymer composition (C-1). The thickness ratio between the layers
of the film was 80 .mu.m/10 .mu.m/10 .mu.m ((A-1) (B-1)/(C-7)).
Comparative Example 4 A single layer film of the 4-methyl-1-pentene
polymer (A-1) was produced by a T-die extruder. The thickness of
the film was 100 .mu.m.
[0178] Various properties of the films produced in the above
examples and comparative examples were measured. The results are
set forth in Table 1
1 TABLE 1 Three layer film Oxygen Heat perme- Blocking sealing
Propylene polymer ability tendency properties composition *1 *2 *3
Ex.1 polypropylene/1-butene 110,000 no possible polymer = 60/40
Ex.2 polypropylene/1-butene 95,000 no possible polymer = 80/20 Ex.3
polypropylene/propylene- 120,000 no possible ethylene copolymer =
60/40 Ex.4 polypropylene/propylene- 100,000 no possible ethylene
copolymer = 80/20 Comp polypropylene/ -- = 100/0 80,000 no possible
Ex.1 Comp polypropylene/propylene- 160,000 yes possible Ex.2
ethylene copolymer = 40/60 Comp polypropylene/1-butene 150,000 yes
possible Ex.3 copolymer = 40/60 Comp no propylene polymer 210,000
no im- Ex.4 composition layer possible *1: The oxygen permeability
is expressed in cm.sup.3/m.sup.2.multidot. d .multidot. MPa. *2:
Propylene polymer layers superposed upon each other were heated at
120.degree. C. for 30 minutes under a load of 100 g/cm.sup.2 to
examine whether blocking of the layers took place. *3: Propylene
polymer layers superposed upon each other were heated at
180.degree. C. for 5 seconds under a load of 100 g/cm.sup.2 to
examine whether heat sealing was possible.
[0179] The resins used for forming resin laminates or films in the
below-described Examples 5 to 10, Comparative Examples 5 and 6, and
Reference Examples 1 to 4 are as follows.
[0180] TPX (1): a copolymer of 4-methyl-1-pentene, 1-tetradecene
and 1-dodecene, available from Mitsui Chemicals, Inc., trade name:
MX021, density: 0.83 g/cm.sup.3, MFR: 4 g/10 min, oxygen
permeability constant: 1,500 cc.multidot.mm/m.sup.2.multidot.24
hr.multidot.atm
[0181] TPX (2): a copolymer of 4-methyl-1-pentene and 1-decene,
available from Mitsui Chemicals, Inc., trade name: DX810, density:
0.83 g/cm.sup.3, MFR: 4 g/10 min, oxygen permeability constant:
1,500 cc.multidot.mm/m.sup.2.multidot.24 hr.multidot.atm
[0182] PB: a 1-butene polymer, available from Mitsui Chemicals,
Inc., trade name: BL3080, density: 0.89 g/cm.sup.3, MFR: 0.2 g/10
min, oxygen permeability constant: 500
cc.multidot.mm/m.sup.2.multidot.24 hr.multidot.atm
[0183] r-PP: a propylene polymer, available from Mitsui Chemicals,
Inc., trade name: F327, density: 0.91 g/cm.sup.3, MFR: 7 g/10 min,
oxygen permeability constant: 100
cc.multidot.mm/m.sup.2.multidot.24 hr.multidot.atm
[0184] PER: a propylene/ethylene copolymer, available from Mitsui
Chemicals, Inc., trade name: S4030, density: 0.89 g/cm.sup.3, MFR:
0.2 g/10 min, oxygen permeability constant: 240
cc.multidot.mm/m.sup.2.multid- ot.24 hr.multidot.atm
[0185] TF-A: an ethylene polymer, available from Mitsui Chemicals,
Inc., trade name: A4085, density: 0.88 g/cm.sup.3, MFR: 3.6 g/10
min, oxygen permeability constant: 510
cc.multidot.mm/m.sup.2.multidot.24 hr.multidot.atm
[0186] TF-XR: a propylene polymer, available from Mitsui Chemicals,
Inc., trade name: XR110T, density: 0.89 g/cm.sup.3, MFR: 3.2 g/10
min, oxygen permeability constant: 240
cc.multidot.mm/m.sup.2.multidot.24 hr.multidot.atm
[0187] Modified PE (1): maleic acid-modified polyethylene,
available from Mitsui Chemicals, Inc., trade name: NE070, density:
0.93 g/cm.sup.3, MFR: 1.0 g/10 min, oxygen permeability constant:
250 cc.multidot.mm/m.sup.2.mu- ltidot.24 hr.multidot.atm
[0188] Modified PE (2): maleic acid-modified polyethylene,
available from Mitsui Chemicals, Inc., trade name: HE040, density:
0.95 g/cm.sup.3, MFR: 2.0 g/10 min, oxygen permeability constant:
200 cc.multidot.mm/m.sup.2.mu- ltidot.24 hr.multidot.atm
[0189] LLDPE: linear low-density polyethylene, available from
Mitsui Chemicals, Inc., trade name: UZ0521L, density: 0.91
g/cm.sup.3, MFR: 2.0 g/10 min, oxygen permeability constant: 200
cc.multidot.mm/m.sup.2.multid- ot.24 hr.multidot.atm
Example 5
[0190] Using the resins and the composition shown in Table 2 as the
4-methyl-1-pentene polymer, the adhesive resin composition and the
olefin polymer, a three-layer resin laminate having a thickness of
30 .mu.m (TPX (1)/adhesive resin composition/r-PP=10/10/10 .mu.m)
was produced by a film molding machine. The die temperature was
280.degree. C., and the die was set to have a clearance of 0.5 mm.
The extrusion temperature of the 4-methyl-1-pentene polymer was
280.degree. C., the extrusion temperature of the adhesive resin
composition was 250.degree. C., and the extrusion temperature of
the olefin polymer was 220.degree. C. The oxygen permeability of
the resin laminate was measured, and the oxygen permeability
constant thereof was calculated. Further, the peel strength of the
laminate was measured. The results are set forth in Table 2.
[0191] The adhesive resin compositions used in Examples 5 to 8 were
each prepared in the same manner as in Example 1, except that the
components shown in Table 2 were used in the quantity ratio shown
in Table 2.
Examples 6-8
[0192] A resin laminate was produced in the same manner as in
Example 5, except that the resins and the composition shown in
Table 2 were used as the 4-methyl-1-pentene polymer, the adhesive
resin composition and the olefin polymer. The oxygen permeability
of the resin laminate was measured, and the oxygen permeability
constant thereof was calculated. Further, the peel strength of the
laminate was measured. The results are set forth in Table 2.
Comparative Examples 5, 6
[0193] A resin laminate was produced in the same manner as in
Example 5, except that the resins shown in Table 2 were used as the
4-methyl-1-pentene polymer and the olefin polymer, and the resin
shown in Table 2 was used in place of the adhesive resin
composition. The oxygen permeability of the resin laminate was
measured, and the oxygen permeability constant thereof was
calculated. Further, the peel strength of the laminate was
measured. The results are set forth in Table 2.
[0194] As shown in Table 2, the oxygen permeability of the layers
made of the adhesive resin compositions in the
poly-4-methyl-1-pentene resin laminates of the invention is higher
than that of the layers made of the hitherto known adhesive resins
(e.g., modified polyolefins in the comparative examples), and
therefore the poly-4-methyl-1-pentene resin laminates of the
invention have higher oxygen permeability as a whole. Accordingly,
it can be seen that the poly-4-methyl-1-pentene resin laminates of
the invention are suitable as materials of packaging media of
vegetables and fruits.
2 TABLE 2 Oxygen permeability constant 4-methyl- ((cc .multidot.
mm/m.sup.2 .multidot. 24 hr .multidot. atm) Adhesion 1-pentene
Adhesive resin composition Olefin Adhesive resin Resin strength
copolymer Components Weight ratio polymer layer laminate (N/15 mm)
Ex. 5 TPX(1) TPX(1)/PB 90/10 r-PP 1260 260 3.0 Ex. 6 TPX(1)
TPX(1)/r-PP 90/10 r-PP 660 245 2.4 Ex. 7 TPX(1) TPX(1)/ 55/30/15
r-PP 640 245 2.5 PB/PER Ex. 8 TPX(1) TPX(2)/PB/ 30/10/50/10 LLDPE
570 400 0.8 TF-A/TF-XR Comp. TPX(1) modified PE(1) -- r-PP 250 200
1.5 Ex. 5 Comp. TPX(1) modified PE(2) -- r-PP 240 190 1.7 Ex. 6
Reference Example 1
[0195] A copolymer of 4-methyl-1-pentene and 1-tetradecene (4-MP/TD
copolymer, 4-methyl-1-pentene/1-tetradecene (content ratio by
weight)=95/5) was fed to an extruder, heated at 260.degree. C. to
melt it, then kneaded and extruded from a T-die to produce a film
having a thickness of 50 .mu.m. The oxygen permeability of the film
was measured.
[0196] Using the film, a bag having a size of about 12.times.12 cm
was produced by a side sealing machine. An asparagus was cut in
half and introduced into the bag. Then, the bag was sealed and
subjected to a freshness keeping test. The result is set forth in
Table 3.
Reference Example 2
[0197] Using a resin composition consisting of 90 parts by weight
of the 4-MP/TD copolymer and 10 parts by weight of poly-1-butene
(trade name: M3080, available from Mitsui Petrochemical Industries,
Ltd.), a film having a thickness of 50 .mu.m was produced in the
same manner as in Reference Example 1. The oxygen permeability of
the film was measured.
[0198] A bag was produced in the same manner as in Reference
Example 1. About a half the bag was charged with cut cabbage. Then,
the bag was sealed and subjected to a freshness keeping test. The
result is set forth in Table 3.
Reference Example 3
[0199] A freshness keeping test was carried out in the same manner
as in Reference Example 1, except that a polyethylene bag
(thickness: 30 .mu.m) was used. The result is set forth in Table
3.
Reference Example 4
[0200] A freshness keeping test was carried out in the same manner
as in Reference Example 2, except that a polyethylene bag
(thickness: 30 .mu.m) was used. The result is set forth in Table
3.
3 TABLE 3 Odygen Packing medium Film Oxygen perme- 4-MP/TD thick-
perme- ability Freshness keeping test copolymer Poly-1-butene ness
ability constant Asparaguas Cut cabbage (part(s)) (part(s)) (.mu.m)
V *1 k *2 1 2 3 4 5 1 2 3 4 5 Ref. 100 0 50 40000 2000 AA AA AA BB
BB Ex.1 Ref. 90 10 50 35000 1750 AA AA AA AA AA Ex.2 Ref.
Polyethylene 30 1800 54 AA BB BB BB BB Ex.3 Ref. Polyethylene 30
1800 54 AA AA BB CC CC Ex.4 4-MP/TD copolymer:
4-methyl-1-pentene/1-tetradecene copolymer *1: The oxygen
permeability is expressed in cc/m.sup.2 .multidot. 24 hr .multidot.
atm. *2: The oxygen permeablity constant is expresed in cc
.multidot. mm/m.sup.2 .multidot. 24 hr .multidot. atm.
* * * * *