U.S. patent application number 10/601871 was filed with the patent office on 2005-06-02 for film for fastening cargo during transportation and method for fastening cargo using the same.
This patent application is currently assigned to Mitsui Chemicals, Inc.. Invention is credited to Arimoto, Masashi, Kimura, Tomohiko, Takeyama, Saburou.
Application Number | 20050118444 10/601871 |
Document ID | / |
Family ID | 29996671 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050118444 |
Kind Code |
A9 |
Arimoto, Masashi ; et
al. |
June 2, 2005 |
FILM FOR FASTENING CARGO DURING TRANSPORTATION AND METHOD FOR
FASTENING CARGO USING THE SAME
Abstract
A film and method for fastening cargo during transportation
wherein the film has a percentage strain change 100 hours after
applying a load of 3.5 MPa at a temperature of 23.degree. C. of not
more than 2.0%, and a percentage strain change 100 hours after
applying a load of 0.5 MPa at a temperature of 55.degree. C. of not
more than 2.5%. Moreover, it is preferable for the elastic modulus
at a temperature of 23.degree. C. to be not more than 60 MPa, and
the elastic modulus at a temperature of 55.degree. C. to be not
more than 20 MPa. Such a film can be formed from substantially
random interpolymer(s) each comprising 1 to 99 mol % of polymer
units derived from an aromatic vinyl or vinylidene monomer and/or a
hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer,
and 1 to 99 mol % of polymer units derived from at least one
.alpha.-olefin having 2 to 20 carbon atoms. The above film has a
low percentage strain change compared with films made of EVA or a
urethane resin, and hence the ability to hold/fasten products
during transportation is excellent, and thus the products can be
prevented from being damaged.
Inventors: |
Arimoto, Masashi;
(Sodegaura-shi, JP) ; Kimura, Tomohiko; (Kuga-gun,
JP) ; Takeyama, Saburou; (Ichihara-shi, JP) |
Correspondence
Address: |
BURNS DOANE SWECKER & MATHIS L L P
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
Mitsui Chemicals, Inc.
Tokyo
JP
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 0048085 A1 |
March 11, 2004 |
|
|
Family ID: |
29996671 |
Appl. No.: |
10/601871 |
Filed: |
June 24, 2003 |
Current U.S.
Class: |
428/515;
428/521 |
Current CPC
Class: |
Y10T 428/31909 20150401;
C08J 5/18 20130101; Y10T 428/31931 20150401; C08J 2355/00
20130101 |
Class at
Publication: |
428/515;
428/521 |
International
Class: |
B32B 027/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2002 |
JP |
2002-182996 |
Claims
What is claimed is:
1. A film, wherein a percentage strain change 100 hours after
applying a load of 3.5 MPa at a temperature of 23.degree. C. is not
more than 2.0%, and a percentage strain change 100 hours after
applying a load of 0.5 MPa at a temperature of 55.degree. C. is not
more than 2.5%.
2. The film according to claim 1, wherein the elastic modulus at a
temperature of 23.degree. C. is not more than 60 MPa, and the
elastic modulus at a temperature of 55.degree. C. is not more than
20 MPa.
3. The film according to claim 1, which comprises at least one
substantially random interpolymer comprising: (1) 1 to 99 mol % of
polymer units derived from (a) at least one aromatic vinyl or
vinylidene monomer, or (b) at least one hindered aliphatic or
cycloaliphatic vinyl or vinylidene monomer, or (c) a combination of
at least one aromatic vinyl or vinylidene monomer, and at least one
hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer,
and (2) 1 to 99 mol % of polymer units derived from at least one
.alpha.-olefin having 2 to 20 carbon atoms.
4. The film according to claim 3, wherein said interpolymer is a
substantially random interpolymer comprising 5 to 65 mol % of
polymer units derived from at least one aromatic vinyl or
vinylidene monomer, and 35 to 95 mol % of polymer units derived
from at least one .alpha.-olefin having 2 to 20 carbon atoms.
5. The film according to claim 3, wherein said interpolymer is a
substantially random interpolymer comprising 5 to 65 mol % of
polymer units derived from styrene, and 35 to 95 mol % of polymer
units derived from at least one .alpha.-olefin having 2 to 10
carbon atoms.
6. The film according to claim 3, wherein said interpolymer is a
pseudo-random interpolymer comprising 5 to 50 mol % of polymer
units derived from at least one aromatic vinyl or vinylidene
monomer, and 50 to 95 mol % of polymer units derived from at least
one .alpha.-olefin having 2 to 20 carbon atoms.
7. The film according to claim 3, wherein said interpolymer is a
pseudo-random interpolymer comprising 5 to 50 mol % of polymer
units derived from styrene, and 50 to 95 mol % of polymer units
derived from at least one .alpha.-olefin having 2 to 10 carbon
atoms.
8. A method for fastening cargo using a film comprising fastening
or holding the cargo with a film having a percentage strain change
100 hours after applying a load of 3.5 MPa at a temperature of
23.degree. C. that is not more than 2.0%, and a percentage strain
change 100 hours after applying a load of 0.5 MPa at a temperature
of 55.degree. C. that is not more than 2.5%.
9. The method for fastening cargo according to claim 8, wherein the
elastic modulus of the film at a temperature of 23.degree. C. is
not more than 60 MPa, and the elastic modulus of the film at a
temperature of 55.degree. C. is not more than 20 MPa.
10. The method for fastening cargo according to claim 8, wherein
the film comprises at least one substantially random interpolymer
comprising: (1) 1 to 99 mol % of polymer units derived from (a) at
least one aromatic vinyl or vinylidene monomer, or (b) at least one
hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer,
or (c) a combination of at least one aromatic vinyl or vinylidene
monomer, and at least one hindered aliphatic or cycloaliphatic
vinyl or vinylidene monomer, and (2) 1 to 99 mol % of polymer units
derived from at least one .alpha.-olefin having 2 to 20 carbon
atoms.
11. The method for fastening cargo according to claim 10, wherein
said interpolymer is a substantially random interpolymer comprising
5 to 65 mol % of polymer units derived from at least one aromatic
vinyl or vinylidene monomer, and 35 to 95 mol % of polymer units
derived from at least one .alpha.-olefin having 2 to 20 carbon
atoms.
12. The method for fastening cargo according to claim 10, wherein
said interpolymer is a substantially random interpolymer comprising
5 to 65 mol % of polymer units derived from styrene, and 35 to 95
mol % of polymer units derived from at least one .alpha.-olefin
having 2 to 10 carbon atoms.
13. The method for fastening cargo according to claim 10, wherein
said interpolymer is a pseudo-random interpolymer comprising 5 to
50 mol % of polymer units derived from at least one aromatic vinyl
or vinylidene monomer, and 50 to 95 mol % of polymer units derived
from at least one .alpha.-olefin having 2 to 20 carbon atoms.
14. The method for fastening cargo according to claim 10, wherein
said interpolymer is a pseudo-random interpolymer comprising 5 to
50 mol % of polymer units derived from styrene, and 50 to 95 mol %
of polymer units derived from at least one .alpha.-olefin having 2
to 10 carbon atoms.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a film for fastening cargo
during transportation, and more specifically to a protective film
that has a low percentage strain change, and has excellent ability
to hold/fasten products. The present invention also relates to a
method for fastening cargo using the film.
[0003] 2. Description of the Related Art
[0004] Fastening film is used for the purpose of holding/fastening
products (cargo) during transportation with a method in which the
products are fastened directly in corrugated cardboard, or a method
in which the products are held in a midair state sandwiched between
a pair of films. Because the purpose of fastening film is to
hold/fasten products during transportation, the fastening film is
required to have properties such that the products are not
subjected to shock and are not damaged. Moreover, fastening film is
used throughout the year over a broad temperature range, and the
properties in a normal temperature range in which usage is common
(around 23.degree. C.) and in a high temperature range in which the
film stretches easily (above 50.degree. C.) are particularly
important.
[0005] Fastening films used from hitherto include resin films made
of EVA, urethane resins and so on.
[0006] With such a fastening film, the elastic modulus and the
percentage strain change are high, with the elastic modulus
exceeding 60 MPa and the percentage strain change exceeding 2.0% at
23.degree. C., and the elastic modulus being at least 20 MPa and
the percentage strain change being at least 2.5% at 55.degree. C.,
and hence it is difficult to stabilize products with the fastening
film not fitting to the products during transportation, and thus
problems arise such as the products being damaged. There are thus
calls for a film having a low percentage strain change at
23.degree. C. and 55.degree. C.
[0007] Amid this state of affairs, a film that uses a urethane
resin and is used in a state of suspension in which a computer
product or the like is sandwiched in midair has been proposed (U.S.
Pat. No. 6,148,591). Moreover, a film of an ethylene-styrene random
copolymer has also been proposed (WO 98/10014).
[0008] However, in these patent documents, there is no mention
whatsoever of the percentage strain change at certain
temperatures.
[0009] The advent of a film that has a low percentage strain change
at certain temperatures, preferably has a low elastic modulus, and
has excellent ability to hold/fasten products during transportation
is thus desired.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to resolve problems
of the prior art as described above, and to provide a film for
fastening cargo during transportation that has a low percentage
strain change compared with films made of EVA or a urethane resin.
A film for fastening cargo during transportation according to the
present invention is characterized in that a percentage strain
change 100 hours after applying a load of 3.5 MPa at a temperature
of 23.degree. C. is not more than 2.0%, and a percentage strain
change 100 hours after applying a load of 0.5 MPa at a temperature
of 55.degree. C. is not more than 2.5%. It is preferable for the
film for fastening cargo during transportation to have an elastic
modulus of not more than 60 MPa at a temperature of 23.degree. C.,
and an elastic modulus of not more than 20 MPa at a temperature of
55.degree. C.
[0011] Specifically, such film preferably contains at least one
substantially random interpolymer comprising:
[0012] (1) 1 to 99 mol % of polymer units derived from
[0013] (a) at least one aromatic vinyl or vinylidene monomer,
or
[0014] (b) at least one hindered aliphatic or cycloaliphatic vinyl
or vinylidene monomer, or
[0015] (c) a combination of at least one aromatic vinyl or
vinylidene monomer, and at least one hindered aliphatic or
cycloaliphatic vinyl or vinylidene monomer, and
[0016] (2) 1 to 99 mol % of polymer units derived from at least one
.alpha.-olefin having 2 to 20 carbon atoms.
[0017] As such an interpolymer, it is preferable to use a
substantially random interpolymer comprising 5 to 65 mol % of
polymer units derived from at least one aromatic vinyl or
vinylidene monomer, and 35 to 95 mol % of polymer units derived
from at least one .alpha.-olefin having 2 to 20 carbon atoms, and
it is particularly preferable to use a substantially random
interpolymer comprising 5 to 65 mol % of polymer units derived from
styrene, and 35 to 95 mol % of polymer units derived from at least
one a-olefin having 2 to 10 carbon atoms.
[0018] Moreover, as such an interpolymer, it is preferable to use a
pseudo-random interpolymer comprising 5 to 50 mol % of polymer
units derived from at least one aromatic vinyl or vinylidene
monomer, and 50 to 95 mol % of polymer units derived from at least
one .alpha.-olefin having 2 to 20 carbon atoms, and it is
particularly preferable to use a pseudo-random interpolymer
comprising 5 to 50 mol % of polymer units derived from styrene, and
50 to 95 mol % of polymer units derived from at least one
.alpha.-olefin having 2 to 10 carbon atoms.
[0019] Here, as disclosed in Japanese Patent Application Laid-open
No. 7-070223, `pseudo` in `pseudo-random interpolymer` means that
there are no homopolymer segments comprising a vinyl or vinylidene
monomer in the interpolymer molecular structure. That is, in a
pseudo-random interpolymer, insertion of a vinyl or vinylidene
monomer from head to head or from head to tail does not occur.
[0020] Another object of the present invention is to provide a
method for fastening cargo using the films described above.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] Following is a concrete description of the film for
fastening cargo during transportation according to the present
invention.
[0022] As mentioned above, the film for fastening cargo during
transportation according to the present invention contains at least
one substantially random interpolymer.
Interpolymers
[0023] An interpolymer that can be used in the present invention is
a substantially random interpolymer comprising
[0024] (1) 1 to 99 mol % of polymer units derived from
[0025] (a) at least one aromatic vinyl or vinylidene monomer,
or
[0026] (b) at least one hindered aliphatic or cycloaliphatic vinyl
or vinylidene monomer, or
[0027] (c) a combination of at least one aromatic vinyl or
vinylidene monomer, and at least one hindered aliphatic or
cycloaliphatic vinyl or vinylidene monomer, and
[0028] (2) 1 to 99 mol % of polymer units derived from at least one
.alpha.-olefin having 2 to 20 carbon atoms.
[0029] The term `interpolymer` used here means a copolymer in the
case of polymerizing at least two monomers to form an
interpolymer.
[0030] `Copolymer` used here means a polymer in the case of
polymerizing at least two monomers to form a copolymer.
[0031] `Substantially random` used here in the substantially random
interpolymer comprising .alpha.-olefin(s), and aromatic vinyl
monomer(s), aromatic vinylidene monomer(s), hindered aliphatic
vinyl monomer(s), hindered cycloaliphatic vinyl monomer(s),
hindered aliphatic vinylidene monomer(s) or hindered cycloaliphatic
vinylidene monomer(s) means that the monomer distribution in the
interpolymer can be described by a `Bernoulli statistical model` or
by a `first or second order Markovian statistical model`, as
described by J. C. Randall on pages 71 to 78 of `Polymer Sequence
Determination, Carbon-13 NMR Method` published in 1977 by Academic
Press, New York.
[0032] Preferably, a substantially random interpolymer comprising
at least one .alpha.-olefin having 2 to 20 carbon atoms and an
aromatic vinyl or vinylidene monomer contains blocks of more than 3
aromatic vinyl or vinylidene monomer units (e.g. styrene monomer
units of 4 or more repeat units derived from styrene) in an amount
of not more than 15% of the total amount of aromatic vinyl or
vinylidene monomer units. More preferably, this interpolymer cannot
be characterized by a high degree of isotacticity or
syndiotacticity. This means that in the .sup.13C NMR spectrum of
the substantially random interpolymer, the peak area corresponding
to main chain methylene and methine carbons that exhibit either a
meso diad sequence or a racemic diad sequence should not exceed 75%
of the total peak area for main chain methylene and methine
carbons.
[0033] Interpolymers suitable for use in the present invention
include interpolymers obtained by polymerizing at least one
.alpha.-olefin with at least one aromatic vinyl or vinylidene
monomer and/or at least one hindered aliphatic or cycloaliphatic
vinyl or vinylidene monomer, although there is no limitation
thereto.
[0034] Examples of preferable .alpha.-olefins are .alpha.-olefins
having 2 to 20 carbon atoms, preferably 2 to 12, more preferably 2
to 8. Out of these, ethylene, propylene, 1-butene,
4-methyl-1-pentene, 1-hexene, and 1-octene are particularly
preferable. These .alpha.-olefins do not contain aromatic
groups.
[0035] Examples of aromatic vinyl or vinylidene monomers suitable
for use in the manufacture of an interpolymer that can be used in
the present invention include monomers represented by the following
formula. 1
[0036] In this formula, R.sup.1 is an atom or group selected from
the group consisting of a hydrogen atom and alkyl groups having 1
to 4 carbon atoms, and is preferably a hydrogen atom or a methyl
group.
[0037] Each R.sup.2 is independently an atom or group selected from
the group consisting of a hydrogen atom and alkyl groups having 1
to 4 carbon atoms, and is preferably a hydrogen atom or a methyl
group.
[0038] Ar is a phenyl group, or a phenyl group substituted with 1
to 5 substituents selected from the group consisting of halogen
atoms, alkyl groups having 1 to 4 carbon atoms, and haloalkyl
groups having 1 to 4 carbon atoms.
[0039] n is an integer from 0 to 4, preferably 0 to 2, most
preferably 0.
[0040] Specific examples of aromatic monovinyl or monovinylidene
monomers are styrene, vinyltoluene, .alpha.-methylstyrene,
t-butylstyrene, chlorostyrene, and so on, with all isomers thereof
being included. Particularly preferable aromatic monovinyl or
monovinylidene monomers are styrene, and lower alkyl- and
halogen-substituted derivatives thereof. Preferable monomers are
styrene, .alpha.-methylstyrene, lower (C.sub.1-4) alkyl- and phenyl
ring-substituted derivatives of styrene, for example ortho-, meta-
and para-methylstyrene, ring-substituted styrene, and
para-vinyltoluene, and also mixtures thereof. A particularly
preferable aromatic monovinyl or monovinylidene monomer is
styrene.
[0041] The previously mentioned term `hindered aliphatic or
cycloaliphatic vinyl or vinylidene compounds` means vinyl or
vinylidene monomers capable of undergoing addition polymerization
corresponding to compounds represented by the following formula.
2
[0042] In this formula, A.sup.1 is a sterically bulky aliphatic or
cycloaliphatic substituent having no more than 20 carbon atoms.
[0043] R.sup.1 is an atom or group selected from the group
consisting of a hydrogen atom and alkyl groups having 1 to 4 carbon
atoms, and is preferably a hydrogen atom or a methyl group.
[0044] Each R.sup.2 is independently an atom or group selected from
the group consisting of a hydrogen atom and alkyl groups having 1
to 4 carbon atoms, and is preferably a hydrogen atom or a methyl
group.
[0045] R.sup.1 and A.sup.1 may be combined to form a ring
system.
[0046] `sterically bulky` above means that a monomer having such an
aliphatic or cycloaliphatic substituent cannot undergo ordinary
addition polymerization at a rate comparable with that of ethylene
polymerization using a standard Ziegler-Natta catalyst.
[0047] Preferable hindered aliphatic or cycloaliphatic vinyl or
vinylidene compounds are monomers that have an ethylenic
unsaturated bond and have one carbon atom that has been subjected
to tertiary or quaternary substitution. Examples of the
substituents are cycloaliphatic groups such as cyclohexyl,
cyclohexenyl and cyclooctenyl, and cyclic alkyl- and
aryl-substituted derivatives thereof. The most preferable hindered
aliphatic or cycloaliphatic vinyl or vinylidene compounds are
various isomeric vinyl-substituted derivatives of cyclohexane and
substituted cyclohexanes, and 5-ethylidene-2-norbornene.
Particularly preferable are 1-, 3- and 4-vinylcyclohexene.
[0048] An interpolymer used in the present invention obtained by
polymerizing at least one .alpha.-olefin, and at least one aromatic
vinyl or vinylidene monomer and/or at least one hindered aliphatic
or cycloaliphatic vinyl or vinylidene monomer is a substantially
random copolymer. Such interpolymers generally contain 1 to 99 mol
%, preferably 5 to 65 mol %, more preferably 5 to 50 mol %, of at
least one aromatic vinyl or vinylidene monomer and/or at least one
hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer,
and 1 to 99 mol %, preferably 35 to 95 mol %, more preferably 50 to
95 mol %, of at least one .alpha.-olefin having 2 to 20 carbon
atoms.
[0049] The number average molecular weight (Mn) of the interpolymer
is generally at least 10,000, preferably 20,000 to 1,000,000, more
preferably 50,000 to 500,000.
[0050] Incidentally, during manufacture of such a substantially
random interpolymer, a certain amount of an atactic aromatic vinyl
or vinylidene homopolymer may be produced through
homopolymerization of an aromatic vinyl or vinylidene monomer under
heating. The presence of an aromatic vinyl or vinylidene
homopolymer is in general undesirable in terms of the object of the
present invention, and cannot be ignored. If desired, such an
aromatic vinyl or vinylidene homopolymer can be separated from the
interpolymer through an extraction technique in which, for example,
either the interpolymer or the aromatic vinyl or vinylidene
homopolymer is selectively precipitated from the solution using a
nonsolvent therefor. In view of the object of the present
invention, it is desirable for the amount present of an aromatic
vinyl or vinylidene homopolymer to be not more than 20 wt %,
preferably not more than 15 wt %, of the total amount of the
interpolymer.
[0051] A substantially random interpolymer can be manufactured as
described in U.S. patent application Ser. No. 07/545,403 filed on
Jul. 3, 1990 by James C. Stevens et al. (corresponding to
EP-A-0,416,815), and U.S. patent application Ser. No. 08/469,828,
which was filed on Jun. 6, 1995 and was approved (U.S. Pat. No.
5,703,187). All of the disclosures in these U.S. patent
applications are incorporated herein. Preferable operating
conditions in the polymerization reaction of these U.S. patent
applications are a pressure of atmospheric pressure to 3,000
atmospheres, and a temperature of -30 to 200.degree. C. If
polymerization and removal of unreacted monomers are carried out at
a temperature higher than the automatic polymerization temperature
of the respective monomers, then a certain amount of homopolymer
polymerization products may be produced through free radical
polymerization.
[0052] Examples of preferable catalysts and methods for
manufacturing substantially random interpolymers that can be used
in the present invention are disclosed in U.S. patent application
Ser. No. 07/545,403, which was filed on Jul. 3, 1990 and
corresponds to EP-A-416,815; U.S. patent application Ser. No.
07/702,475, which was filed on May 20, 1991 and corresponds to
EP-A-514,828; U.S. patent application Ser. No. 07/876,268, which
was filed on May 1, 1992 and corresponds to EP-A-520,732; U.S.
patent application Ser. No. 08/241,523, which was filed on May 12,
1994 (U.S. Pat. No. 5,470,993); and U.S. Pat. Nos. 5,055,438,
5,057,475, 5,096,867, 5,064,802, 5,132,380, 5,189,192, 5,321,106,
5,347,024, 5,350,723, 5,374,696, 5,399,635, and 5,556,928. All of
the disclosures therein are incorporated herein.
[0053] Substantially random .alpha.-olefin/aromatic vinyl or
vinylidene interpolymers that can be used in the present invention
can also be manufactured using the method described in WO95/32095
by John C. Bradfute et al. (W. R. Grace & Co.), the method
described in WO94/00500 by R. B. Pannell (Exxon Chemical Patents,
Inc.), and the method described on page 25 in `Plastics Technology`
(September 1992); all of the disclosures therein are incorporated
herein as well.
[0054] Moreover, substantially random interpolymers comprising at
least one .alpha.-olefin/aromatic vinyl/aromatic
vinyl/.alpha.-olefin tetrad disclosed in U.S. patent application
Ser. No. 08/708,809 filed on Sep. 4, 1996 by Francis J. Timmers et
al. (U.S. Pat. No. 5,879,149) are also preferable. These
interpolymers have additional signals having at least three times
the intensity of a peak to peak noise ratio. These signals appear
in the chemical shift ranges 43.75-44.25 ppm and 38.0-38.5 ppm. In
particular, peaks are observed at 44.1, 43.9 and 38.2 ppm. Proton
test NMR experiments show that the signals in the 43.75-44.25 ppm
chemical shift range are methine carbons, and the signals in the
38.0-38.5 ppm range are methylene carbons.
[0055] Pseudo-random interpolymers comprising an aliphatic
.alpha.-olefin and an aromatic monovinyl or monovinylidene compound
that can be used in the present invention are disclosed in U.S.
patent application Ser. No. 545403 filed on Jul. 3, 1990
(corresponding to European Patent Application Laid-open No.
0416815).
[0056] These interpolymers can be manufactured by carrying out
polymerization at a temperature in a range of -30 to 250.degree. C.
in the presence of a catalyst represented by the following formula,
and preferably a cocatalyst if desired. 3
[0057] Here, each Cp is independently a substituted
cyclopentadienyl group that is .alpha.-bonded to M, E is a carbon
or silicon atom, M is a group IV metal, preferably Zr or Hf, most
preferably Zr, each R is independently a hydrogen atom, or a
hydrocarbyl, silahydrocarbyl or hydrocarbylsilyl group having not
more than 30, preferably 1 to 20, more preferably 1 to 10, carbon
or silicon atoms, and each R' is independently a hydrogen atom, a
halogen atom, or a hydrocarbyl, hydrocarbyloxy, silahydrocarbyl or
hydrocarbylsilyl group having not more than 30, preferably 1 to 20,
more preferably 1 to 10, carbon or silicon atoms, or the two R'
groups together form a C.sub.1-10 hydrocarbyl-substituted
1,3-butadiene, and m is 1 or 2. Examples of particularly preferable
substituted cyclopentadienyl group are groups represented by the
following formula. 4
[0058] Here, each R is independently a hydrogen atom, or a
hydrocarbyl, silahydrocarbyl or hydrocarbylsilyl group having not
more than 30, preferably 1 to 20, more preferably 1 to 10, carbon
or silicon atoms, or the two R groups together form a bivalent
derivative thereof. Preferably, each R is independently hydrogen,
methyl, ethyl, propyl, butyl, pentyl, hexyl, benzyl or phenyl
(wherein in the case that isomers exist all of the isomers are
included), or (if possible) the two R groups together form a fused
ring system such as indenyl, fluorenyl, tetrahydroindenyl,
tetrahydrofluorenyl or octahydrofluorenyl.
[0059] Specific examples of particularly preferable catalysts
include racemic
(dimethylsilanediyl)bis(2-methyl-4-phenylindenyl)zirconium
dichloride, racemic
(dimethylsilanediyl)bis(2-methyl-4-phenylindenyl)zirc- onium
1,4-diphenyl-1,3-butadiene, racemic
(dimethylsilanediyl)bis(2-methyl- -4-phenylindenyl)zirconium
di-C.sub.1-4-alkyls, racemic
(dimethylsilanediyl)bis(2-methyl-4-phenylindenyl)zirconium
di-C.sub.1-4-alkoxides, and combinations thereof.
[0060] Moreover, specific examples of titanium-based constrained
geometry catalysts include
[N-(1,1-dimethylethyl)-1,1-dimethyl-1-[(1,2,3,4,5-.eta.-
)-1,5,6,7-tetrahydro-s-indacen-1-yl]silaneaminato(2-)-N] titanium
dimethyl, (1-indenyl)(t-butylamido)dimethylsilane titanium
dimethyl,
((3-t-butyl)(1,2,3,4,5-.eta.)-1-indenyl)(t-butylamido)dimethylsilane
titanium dimethyl,
((3-isopropyl)(1,2,3,4,5-.eta.)-1-indenyl)(t-butylamid-
o)dimethylsilane titanium dimethyl, and combinations thereof.
[0061] Others method of manufacturing interpolymers that can be
used in the present invention are described by Longo and Grassi
(Makromol. Chem., Vol. 191, p2387-2396 (1990)) and D'Aniello et al.
(Journal of Applied Polymer Science, Vol. 58, p1701-1706 (1995));
here, an ethylene-styrene copolymer is prepared using a
methylaluminoxane (MAO) and cyclopentadienyl titanium trichloride
(CpTiCl.sub.3) catalyst system. Moreover, Xu and Lin (Polymer
Preprints, Am. Chem. Soc., Div. Polym. Chem., Vol. 35, p686-687
(1994)) have prepared a random copolymer between styrene and
propylene using an MgCl.sub.2/TiCl.sub.4/NdCl.sub.3/Al(iBu).s- ub.3
catalyst. Furthermore, Lu et al. (Journal of Applied Polymer
Science, Vol. 53, p1453-1460 (1994)) have reported on a copolymer
between ethylene and styrene using a
TiCl.sub.4/NdCl.sub.3/MgCl.sub.2/Al(Et).sub.3 catalyst.
[0062] Sernets and Mulhaupt (Macromol. Chem. Phys., v. 197, pp.
1071-1083, 1997) describe the effects of the polymerization
conditions in the copolymerization of styrene and ethylene using an
Me.sub.2Si(Me.sub.4 Cp) (N-t-butyl)TiCl.sub.2/methylaluminoxane
Ziegler-Natta catalyst. Ethylene-styrene copolymers manufactured
using a bridged metallocene catalyst are described by Arai,
Toshiaki and Suzuki (Polymer Preprints, Am. Chem. Soc., Div. Polym.
Chem., Vol. 38, p349-350, 1997) and in U.S. Pat. No. 5,652,315
(Mitsui Toatsu Chemicals, Inc.). The manufacture of interpolymers
comprising an .alpha.-olefin and an aromatic vinyl monomer (e.g.
propylene/styrene or butene/styrene) is described in U.S. Pat. No.
5,244,996 (Mitsui Petrochemical Industries, Ltd.) and U.S. Pat. No.
5,652,315 (Mitsui Petrochemical Industries, Ltd.), and is also
described in German publication DE19711339A1, U.S. Pat. No.
5,883,213 (Denki Kagaku Kogyo K.K.), and so on. The interpolymer
component preparation methods disclosed in the above are
incorporated into the present invention as reference documents. The
ethylene/styrene random copolymer disclosed by Aria et al. in
Polymer Preprints, Vol. 39, No. 1, March 1998 can also be used a
component in the present invention.
[0063] Examples of suitable catalysts and methods for manufacturing
pseudo-random interpolymers that are suitable for use in the
present invention are disclosed in the specifications of U.S.
patent application Ser. No. 545403 filed on Jul. 3, 1990 (European
Patent Application Laid-open No. 0416815), U.S. patent application
Ser. No. 547718 filed on Jul. 3, 1990 (European Patent Application
Laid-open No. 468651), U.S. patent application Ser. No. 702475
filed on May 20, 1991 (European Patent Application Laid-open No.
514828), U.S. patent application Ser. No. 876268 filed on May 1,
1992 (European Patent Application Laid-open No. 520732), U.S.
patent application Ser. No. 8003 filed on Jan. 21, 1993 (U.S. Pat.
No. 5,374,696), U.S. patent application Ser. No. 82197 filed on
Jun. 24, 1993 (corresponding to WO95/00526), and also U.S. patent
application Ser. Nos. 5055438, 5057475, 5096867, 5064802, 5132380
and 5189192; all of these are cited as references for the present
invention.
Film for Fastening Cargo During Transportation
[0064] For a film for fastening cargo during transportation
according to the present invention comprising such interpolymer(s),
the percentage strain change 100 hours after applying a load of 3.5
MPa at a temperature of 23.degree. C. is not more than 2.0%,
preferably 1.4 to 1.7%, and the percentage strain change 100 hours
after applying a load of 0.5 MPa at a temperature of 55.degree. C.
is not more than 2.5%, preferably 2.0 to 2.3%. Moreover, the film
of the present invention preferably has an elastic modulus at a
temperature of 23.degree. C. of not more than 60 MPa, more
preferably 10 to 30 MPa, and preferably has an elastic modulus at a
temperature of 55.degree. C. of not more than 20 MPa, more
preferably 1 to 10 MPa. A film for which the percentage strain
changes at temperatures of 23.degree. C. and 55.degree. C. are low
as above has excellent ability to hold/fasten products (cargo)
during transportation.
[0065] A specific method of measuring the elastic modulus and
percentage strain changes will be described later in the `Examples`
section.
Preparation of Fastening Film
[0066] The fastening film according to the present invention can be
formed using a conventional publicly known method, for example
using an extruder such as a calender apparatus, a T-die apparatus,
or an inflation apparatus. When forming the film, in addition to
the interpolymer(s) described above, additives such as
antioxidants, ultraviolet absorbers, weather-resistant stabilizers,
heat-resistant stabilizers, antistatic agents, fire retardants,
pigments, dyes and slipping agents can be mixed in as required
within ranges such that the object of the present invention is not
impaired.
[0067] The film for fastening cargo during transportation according
to the present invention exhibits effects of the ability to
hold/fasten products during transportation being excellent, and
hence products not being damaged during transportation. Moreover,
the film has a property of pinholes not being prone to occur in a
pinhole resistance test.
EXAMPLES
[0068] Following is a description of the present invention through
examples; however, the present invention is not limited by these
examples whatsoever.
[0069] The percentage strain changes for the films obtained in the
examples and for commercially sold films were measured in
accordance with the following methods.
[0070] (1) Using a tensile test (ASTM-4), a load of 3.5 MPa was
applied to the film (size: thickness 80 .mu.m, length 64 mm, width,
10 mm) at a temperature of 23.degree. C., the strain after 100
hours was measured, and the percentage change in the strain
relative to the initial strain was calculated.
[0071] (2) Using a tensile test (ASTM-4), a load of 0.5 MPa was
applied to the film (size: thickness 80 .mu.m, length 64 mm, width,
10 mm) at a temperature of 55.degree. C., the strain after 100
hours was measured, and the percentage change in the strain
relative to the initial strain was calculated.
[0072] (3) Using a tensile test (ASTM-4), the elastic modulus at a
temperature of 23.degree. C. was determined.
[0073] (4) Using a tensile test (ASTM-4), the elastic modulus at a
temperature of 55.degree. C. was determined.
[0074] (5) Using a Gelbo flex tester, a 205 mm.times.180 mm sample
was twisted in a cylindrical shape 5000 times by 440.degree. at a
speed of 40 times/min, and the number of pinholes in the sample was
measured.
[0075] The interpolymers used in the examples were as follows.
[0076] Interpolymers
[0077] (1) Ethylene-styrene copolymer (interpolymer) (ESI-2008)
[0078] Styrene content: 25 wt %
[0079] MFR (ASTM D 1238, 190.degree. C., 2.16 kg load): 11.0 g/10
min
[0080] (2) Ethylene-styrene copolymer (interpolymer) (ESI-2408)
[0081] Styrene content: 30 wt %
[0082] MFR (ASTM D 1238, 190.degree. C., 2.16 kg load): 1.0 g/10
min
Example 1
[0083] Using a granulator, 100 parts by weight of the
above-mentioned ethylene-styrene copolymer (ESI-2008; made by Dow
Chemical Company), 0.1 parts by weight of Irganox 1010 (trade name;
phenolic antioxidant made by Ciba Specialty Chemicals), 0.1 parts
by weight of Irgafos 168 (trade name; phosphor-based antioxidant
made by Ciba Specialty Chemicals), 0.5 parts by weight of DICALITE
WF (trade name; anti-blocking agent made by Grefco), and 0.5 parts
by weight of Alflow P-10 (trade name; slipping agent made by NOF
Corporation) were subjected to melt kneading, and pellets were
prepared under the following granulating conditions.
[0084] <Granulating Conditions>
[0085] Granulator: Kasamatsu 65 mm single-screw extruder
[0086] L/D: 28
[0087] Mesh: 80/100/80
[0088] Screw diameter: 65 mm
[0089] Rotational speed of screw: 45 rpm
[0090] Extrusion amount: 28 kg/hr
[0091] Temperatures of various parts:
C1/C2/C3/C4/CH1/CH2/D=160/170/190/19- 0/190/190/190.degree. C.
[0092] Next, using an inflation molding machine, an 80 .mu.m-thick
film was formed under the following film formation conditions from
the pellets obtained as described above.
[0093] <Film Formation Conditions>
[0094] Molding machine: Inflation
[0095] L/D: 26
[0096] Screw diameter: 65 mm
[0097] Rotational speed of screw: 37 rpm
[0098] Extrusion amount: 36 kg/hr
[0099] Die diameter: 100 mm
[0100] Temperatures of various parts:
C1/C2/A/D1/D2=180/180/190/190/190.de- gree. C.
[0101] Next, the elastic modulus, percentage strain change and
pinhole resistance for the film obtained were determined following
the methods described earlier. The results are shown in Table
1.
Example 2
[0102] The same was done as in Example 1, except that the
above-mentioned ethylene-styrene copolymer (ESI-2408; made by Dow
Chemical Company) was used instead of the ethylene-styrene
copolymer (ESI-2008). The results are shown in Table 1.
Comparative Example 1
[0103] The same was done as in Example 1, except that a
commercially sold 80 .mu.m-thick EVA film was used instead of the
film obtained in Example 1. The results are shown in Table 1.
Comparative Example 2
[0104] The same was done as in Example 1, except that a
commercially sold 80 .mu.m-thick urethane resin film was used
instead of the film obtained in Example 1. The results are shown in
Table 1.
1 TABLE 1 Example Example Comparative Comparative 1 2 Example 1
Example 2 Percentage 23.degree. C. 1.6 1.5 2.2 2.1 strain
55.degree. C. 2.3 2.1 2.8 3.9 change (%) Elastic 23.degree. C. 48
20 80 62 modulus 55.degree. C. 12 6 27 25 (MPa) Pinhole resistance
0 0 10 5 (number of pinholes)
[0105] The following can be seen from Table 1. With Comparative
Example 1 and Comparative Example 2, the percentage strain change
obtained at a temperature of 23.degree. C. exceeded 2.0%, and the
percentage strain change obtained at a temperature of 55.degree. C.
exceeded 2.5%. If the percentage strain change is high in this way,
then there may be a lack of ability to hold/fasten products (cargo)
during transportation.
[0106] Moreover, with Comparative Example 1 and Comparative Example
2, the elastic modulus (at 23.degree. C. and at 55.degree. C.) was
high, showing that the film was rigid and would be hard to fit to a
product. Moreover, in the pinhole resistance tests, with
Comparative Example 1 and Comparative Example 2, pinholes were
detected. With such a film, the film will be prone to tearing
starting from a pinhole. On the other hand, with Example 1 and
Example 2, the percentage strain change obtained at a temperature
of 23.degree. C. was not more than 2.0%, and the percentage strain
change obtained at a temperature of 55.degree. C. was not more than
2.5%. Moreover, the elastic modulus at 23.degree. C. was not more
than 60 MPa, and the elastic modulus at 55.degree. C. was not more
than 20 MPa. For a film that has a low percentage strain change and
elastic modulus and has excellent pinhole resistance, the ability
to hold/fasten products during transportation is excellent.
* * * * *