U.S. patent application number 13/816693 was filed with the patent office on 2013-06-06 for resin for oxygen-absorbing adhesive and oxygen-absorbing adhesive.
This patent application is currently assigned to TOYO SEIKAN KAISHA LTD.. The applicant listed for this patent is Yui Asano, Yoichi Ishizaki, Yoshihiro Ohta. Invention is credited to Yui Asano, Yoichi Ishizaki, Yoshihiro Ohta.
Application Number | 20130143734 13/816693 |
Document ID | / |
Family ID | 45605208 |
Filed Date | 2013-06-06 |
United States Patent
Application |
20130143734 |
Kind Code |
A1 |
Ohta; Yoshihiro ; et
al. |
June 6, 2013 |
Resin for Oxygen-absorbing Adhesive and Oxygen-absorbing
Adhesive
Abstract
The purpose of the present invention is to provide a
two-component curable oxygen-absorbing resin composition that has
both oxygen-absorbing and adhesive properties and cohesive power.
The resin for an oxygen-absorbing adhesive is a polyester
comprising structural units derived from an acid component (A) and
an acid component (B), wherein the ratio of the acid component (A)
to total acid components is 70 to 95 mol %, the ratio of the acid
component (B) to total acid components is 0 to 15 mol %, the
polyester has a glass transition temperature of -20.degree. C. to
2.degree. C., the resin is cured using a hardening agent, the acid
component (A) is tetrahydrophthalic acid or a derivative thereof,
or tetrahydrophthalic acid anhydride or a derivative thereof, and
the acid component (B) is phthalic acid.
Inventors: |
Ohta; Yoshihiro; (Kanagawa,
JP) ; Ishizaki; Yoichi; (Kanagawa, JP) ;
Asano; Yui; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ohta; Yoshihiro
Ishizaki; Yoichi
Asano; Yui |
Kanagawa
Kanagawa
Kanagawa |
|
JP
JP
JP |
|
|
Assignee: |
TOYO SEIKAN KAISHA LTD.
Tokyo
JP
|
Family ID: |
45605208 |
Appl. No.: |
13/816693 |
Filed: |
August 16, 2011 |
PCT Filed: |
August 16, 2011 |
PCT NO: |
PCT/JP2011/068555 |
371 Date: |
February 12, 2013 |
Current U.S.
Class: |
502/402 ;
528/304 |
Current CPC
Class: |
B32B 7/12 20130101; B65D
81/266 20130101; C09J 167/06 20130101; B32B 2255/06 20130101; C08G
63/54 20130101; Y10T 428/31794 20150401; B32B 2307/74 20130101;
B32B 15/09 20130101; C09J 167/02 20130101; B01J 20/264 20130101;
B32B 2255/26 20130101; C08G 63/183 20130101 |
Class at
Publication: |
502/402 ;
528/304 |
International
Class: |
B01J 20/26 20060101
B01J020/26 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 19, 2010 |
JP |
2010184026 |
Claims
1. A resin for an oxygen-absorbing adhesive, wherein the resin is a
polyester comprising structural units derived from a first acid
component (A) and a second acid component (B), the ratio of the
first acid component (A) is 70% to 95% by mole relative to all acid
components, the ratio of the second acid component (B) is 0 to 15%
by mole relative to all acid components, the glass transition
temperature of the polyester is -20.degree. C. to 2.degree. C., and
the resin is intended to be used after being cured with a curing
agent: the first acid component (A) is a tetrahydrophthalic acid, a
derivative thereof, a tetrahydrophthalic anhydride, or a derivative
thereof, and the second acid component (B) is a phthalic acid.
2. The resin for an oxygen-absorbing adhesive according to claim 1,
wherein the first acid component (A) is a methyltetrahydrophthalic
acid, a derivative thereof, a methyltetrahydrophthalic anhydride,
or a derivative thereof.
3. The resin for an oxygen-absorbing adhesive according to claim 1,
wherein the first acid component (A) contains 50% by mole or more
of an acid component having a structure selected from the group
consisting of (i) and (ii): (i) a dicarboxylic acid or dicarboxylic
anhydride having a carbon atom which is bonded to both groups
having the following structures (a) and (b) and also which is
bonded to one or two hydrogen atoms, the carbon atom being included
in an alicyclic structure: (a) a carbon-carbon double bond group,
(b) a hetero atom-containing functional group or a linking group
derived from the functional group; and (ii) a dicarboxylic acid or
dicarboxylic anhydride in which a carbon atom adjacent to a
carbon-carbon double bond in an unsaturated alicyclic structure is
bonded to an electron-donating substituent and a hydrogen atom,
another carbon atom adjacent to the carbon atom is bonded to a
hetero atom-containing functional group or a linking group derived
from the functional group, and the electron-donating substituent
and the hetero atom-containing functional group or the linking
group derived from the functional group are in a cis
configuration.
4. The resin for an oxygen-absorbing adhesive according to claim 3,
wherein the acid component having the structure of (i) is
4-methyl-.DELTA..sup.3-tetrahydrophthalic acid, a derivative
thereof, 4-methyl-.DELTA..sup.3-tetrahydrophthalic anhydride, or a
derivative thereof, and the acid component having the structure of
(ii) is cis-3-methyl-.DELTA..sup.4-tetrahydrophthalic acid, a
derivative thereof, cis-3-methyl-.DELTA..sup.4-tetrahydrophthalic
anhydride, or a derivative thereof.
5. The resin for an oxygen-absorbing adhesive according to claim 1,
wherein the resin is the polyester further comprising a structural
unit derived from 1,4-butanediol.
6. The resin for an oxygen-absorbing adhesive according to claim 1,
comprising a structural unit derived from an aliphatic dicarboxylic
acid, which is a further acid component, in an amount of 1% to 30%
by mole relative to the all acid components.
7. The resin for an oxygen-absorbing adhesive according to claim 6,
wherein the aliphatic dicarboxylic acid is succinic acid or adipic
acid.
8. A two-part curable oxygen-absorbing resin composition
comprising: a main agent comprising the resin for an
oxygen-absorbing adhesive according to claim 1; and a curing agent
component.
9. An oxygen-absorbing adhesive comprising: the two-part curable
oxygen-absorbing resin composition according to claim 8.
10. An oxygen-absorbing laminated film comprising at least: an
oxygen barrier film layer; an oxygen-absorbing layer made of the
oxygen-absorbing adhesive according to claim 9; and a sealant film
layer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a resin for an
oxygen-absorbing adhesive and an oxygen-absorbing adhesive which
are excellent in adhesion, cohesive force, and oxygen-absorbing
property.
BACKGROUND ART
[0002] For improvement in content storage performances, various
gas-barrier packaging materials have been proposed. In particular,
oxygen-absorbing packaging containers obtained by using materials
having oxygen-absorbing performances for packaging containers have
attracted attention recently. A method in which an oxygen-absorbing
resin composition is used as a paint or an adhesive for coating has
been proposed as a method for achieving an oxygen-absorbing
packaging container.
[0003] Patent Literature 1 proposes an oxygen-absorbing adhesive
obtained by blending an inorganic oxide having oxygen-absorbing
property with a polyol. However, the oxygen-absorbing adhesive has
the following problems and the like. Specifically, the
oxygen-absorbing adhesive is opaque, and poor in oxygen-absorbing
performance. In addition, the oxygen-absorbing adhesive cannot be
used in a dry atmosphere, because the expression of the
oxygen-absorbing performance requires water. Meanwhile, paints and
adhesives using various oxygen-absorbing resins have been proposed
(for example, Patent Literatures 2 and 3). However, there is no
case where oxygen-absorbing property, adhesion, and cohesive force
are all achieved.
CITATION LIST
Patent Literatures
[0004] Patent Literature 1: Japanese Patent Application Publication
No. 2006-131699 [0005] Patent Literature 2: International
Publication No. WO 2006/080500 [0006] Patent Literature 3: Japanese
Patent Application Publication No. 2008-7739
SUMMARY OF INVENTION
Technical Problem
[0007] Accordingly, an object of the present invention is to
provide a two-part curable oxygen-absorbing resin composition
having all of oxygen-absorbing property, adhesion, and cohesive
force.
Solution to Problem
[0008] The present invention provides a resin for an
oxygen-absorbing adhesive, wherein
[0009] the resin is a polyester comprising structural units derived
from an acid component (A) and an acid component (B),
[0010] the ratio of the acid component (A) is 70 to 95% by mole
relative to all acid components,
[0011] the ratio of the acid component (B) is 0 to 15% by mole
relative to the all acid components,
[0012] the glass transition temperature of the polyester is
-20.degree. C. to 2.degree. C., and
[0013] the resin is intended to be used after being cured with a
curing agent:
[0014] the acid component (A): a tetrahydrophthalic acid, a
derivative thereof, a tetrahydrophthalic anhydride, or a derivative
thereof, and
[0015] the acid component (B): a phthalic acid.
[0016] Moreover, the present invention provides a two-part curable
oxygen-absorbing resin composition comprising:
[0017] a main agent comprising the resin for an oxygen-absorbing
adhesive; and
[0018] curing agent component.
[0019] Moreover, the present invention provides an oxygen-absorbing
adhesive comprising the two-part curable oxygen-absorbing resin
composition.
[0020] Further, the present invention provides an oxygen-absorbing
laminated film comprising at least:
[0021] an oxygen barrier film layer;
[0022] an oxygen-absorbing layer made of the oxygen-absorbing
adhesive; and
[0023] a sealant film layer.
Advantageous Effect of Invention
[0024] A flexible packaging material having excellent oxygen
removal performance can be easily produced at low costs by using
the two-part curable oxygen-absorbing resin composition of the
present invention as an adhesive for a multilayer packaging
material, for example, as an alternative to a conventional adhesive
for dry lamination. This oxygen-absorbing flexible packaging
material makes it possible to keep for long periods the qualities
of foods, pharmaceuticals, electronic components, and the like
which are sensitive to oxygen.
DESCRIPTION OF EMBODIMENTS
[0025] A resin for an oxygen-absorbing adhesive of the present
invention is a polyester comprising structural units derived from
an acid component (A) and an acid component (B).
[0026] In the resin for an oxygen-absorbing adhesive of the present
invention, the acid component (A) is a tetrahydrophthalic acid, a
derivative thereof, a tetrahydrophthalic anhydride, or a derivative
thereof. The acid component (A) is preferably a
methyltetrahydrophthalic acid, a derivative thereof, a
methyltetrahydrophthalic anhydride, or a derivative thereof. Here,
the term "derivative" includes esters, acid halides, substituted
compounds, oligomers, and the like.
[0027] Moreover, in the resin for an oxygen-absorbing adhesive of
the present invention, the acid component (A) is preferably as
follows: the acid component (A) contains 50 to 100% by mole and
more preferably 60 to 100% by mole of an acid component having a
structure selected from the group consisting of (i) and (ii):
[0028] (i) a dicarboxylic acid or dicarboxylic anhydride having a
carbon atom which is bonded to both groups having the following
structures (a) and (b) and also which is bonded to one or two
hydrogen atoms, the carbon atom being included in an alicyclic
structure: [0029] (a) a carbon-carbon double bond group, [0030] (b)
a hetero atom-containing functional group or a linking group
derived from the functional group; and
[0031] (ii) a dicarboxylic acid or dicarboxylic anhydride in
which
[0032] a carbon atom adjacent to a carbon-carbon double bond in an
unsaturated alicyclic structure is bonded to an electron-donating
substituent and a hydrogen atom,
[0033] another carbon atom adjacent to the carbon atom is bonded to
a hetero atom-containing functional group or a linking group
derived from the functional group, and
[0034] the electron-donating substituent and the hetero
atom-containing functional group or the linking group derived from
the functional group are in a cis configuration.
[0035] Each of the above-described structures (i) and (ii) is a
molecular structure having particularly excellent reactivity with
oxygen because of the substituent effect. Preferred are acid
components in which the hetero atom-containing functional group or
the linking group derived from the functional group in the
above-described structure (i) or (ii) is the dicarboxylic acid or
the dicarboxylic anhydride in a tetrahydrophthalic acid or
tetrahydrophthalic anhydride structure.
[0036] Examples of the acid component having the structure (i)
include .DELTA..sup.2-tetrahydrophthalic acid derivatives,
.DELTA..sup.3-tetrahydrophthalic acid derivatives,
.DELTA..sup.2-tetrahydrophthalic anhydride derivatives, and
.DELTA..sup.3-tetrahydrophthalic anhydride derivatives. The acid
component having the structure of (i) is preferably a
.DELTA..sup.3-tetrahydrophthalic acid derivative or a
.DELTA..sup.3-tetrahydrophthalic anhydride derivative, and
particularly preferably 4-methyl-.DELTA..sup.3-tetrahydrophthalic
acid or 4-methyl-.DELTA..sup.3-tetrahydrophthalic anhydride.
[0037] 4-Methyl-.DELTA..sup.3-tetrahydrophthalic anhydride can be
obtained by, for example, structural isomerization of an isomer
mixture containing 4-methyl-.DELTA..sup.4-tetrahydrophthalic
anhydride obtained by a reaction of a C.sub.5 fraction of naphtha
mainly containing isoprene with maleic anhydride, and has been
produced industrially.
[0038] The acid component having the structure (ii) is particularly
preferably cis-3-methyl-.DELTA..sup.4-tetrahydrophthalic acid or
cis-3-methyl-.DELTA..sup.4-tetrahydrophthalic anhydride.
cis-3-Methyl-.DELTA..sup.4-tetrahydrophthalic anhydride can be
obtained by, for example, a reaction of a C.sub.5 fraction of
naphtha mainly containing trans-piperylene with maleic anhydride,
and has been produced industrially.
[0039] Moreover, exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride
is an example of acid components in which the hetero
atom-containing functional group or the linking group derived from
the functional group in the above-described structure (i) or (ii)
is not the dicarboxylic acid or the dicarboxylic anhydride in the
tetrahydrophthalic acid or tetrahydrophthalic anhydride
structure.
[0040] There are many compounds which can be shown as examples of
the tetrahydrophthalic acid, the derivative thereof, the
tetrahydrophthalic anhydride, or the derivative thereof. In
particular, acid components having the above-described structure
(i) and acid components having the above-described structure (ii)
are each preferably used as a raw material of the resin for an
oxygen-absorbing adhesive of the present invention, because of
extremely high reactivity with oxygen. One kind of these acid
components having the structure (i) or the structure (ii) may be
used alone. It is also preferable to use two or more kinds thereof
in combination. A mixture of
4-methyl-.DELTA..sup.3-tetrahydrophthalic anhydride, which is
preferred as the acid component having the structure of (i), and
cis-3-methyl-.DELTA..sup.4-tetrahydrophthalic anhydride, which is
preferred as the acid component having the structure (ii), can be
easily obtained as an industrial product at low costs by structural
isomerization of a mixture of
cis-3-methyl-.DELTA..sup.4-tetrahydrophthalic anhydride and
4-methyl-.DELTA..sup.4-tetrahydrophthalic anhydride obtained by a
reaction of a C.sub.5 fraction of naphtha mainly containing
trans-piperylene and isoprene with maleic anhydride. In view of
industrial application, it is particularly preferable to use such
an inexpensive isomer mixture as a raw material of the resin for an
oxygen-absorbing adhesive of the present invention.
[0041] In a case where an oxygen-absorbing polyester, which is the
resin for an oxygen-absorbing adhesive of the present invention, is
polymerized by using a tetrahydrophthalic acid, a derivative
thereof, a tetrahydrophthalic anhydride, or a derivative thereof as
a raw material, the dicarboxylic acid or the dicarboxylic anhydride
may be esterified into a methyl ester or the like.
[0042] Moreover, in order to accelerate the oxygen-absorbing
reaction, an oxygen-absorbing reaction catalyst (an oxidation
catalyst) may be added to the resin for an oxygen-absorbing
adhesive of the present invention obtainable by polymerization of a
raw material containing a tetrahydrophthalic acid, a derivative
thereof, a tetrahydrophthalic anhydride, or a derivative thereof.
However, since the resin for an oxygen-absorbing adhesive of the
present invention obtainable by polymerization of a raw material
containing an acid component having the above-described structure
(i) or an acid component having the above-described structure (ii)
has an extremely high reactivity with oxygen, the resin for an
oxygen-absorbing adhesive of the present invention can exhibit a
practical oxygen-absorbing performance even in the absence of the
oxygen-absorbing reaction catalyst. In addition, in order to
prevent formation of a gel and the like due to excessive
deterioration of the resin caused by the oxygen-absorbing reaction
catalyst when an adhesive is prepared by using the resin for an
oxygen-absorbing adhesive of the present invention or when a
process is carried out by using the adhesive, it is desirable not
to contain a catalytic amount of an oxygen-absorbing reaction
catalyst. Here, examples of the oxygen-absorbing reaction catalyst
include transition metal salts made of organic acids and transition
metals such as manganese, iron, cobalt, nickel, and copper.
Moreover, the phrase "not to contain a catalytic amount of an
oxygen-absorbing reaction catalyst" means that the oxygen-absorbing
reaction catalyst is generally less than 10 ppm, and preferably
less than 1 ppm in terms of the amount of the transition metal.
[0043] In the resin for an oxygen-absorbing adhesive of the present
invention, the acid component (B) is a phthalic acid. Examples of
the phthalic acid being the acid component (B) include o-phthalic
acid, isophthalic acid, terephthalic acid, sulfoisophthalic acid,
5-sulfoisophthalic acid sodium salt, derivatives thereof, and the
like. Here, the derivatives include esters, acid anhydrides, acid
halides, substituted compounds, oligomers, and the like. Of these
phthalic acids, isophthalic acid or terephthalic acid is
particularly preferable. Terephthalic acid is preferable, because
copolymerization with terephthalic acid improves the cohesive force
of the resin itself, and improves the adhesion strength of an
adhesive, so that the delamination can be prevented. Moreover,
isophthalic acid is preferable, because copolymerization with
isophthalic acid improves solubility in a solvent, while
maintaining the cohesive force.
[0044] The ratio of the acid component (A) is 70 to 95% by mole,
preferably 75 to 95% by mole, and more preferably 80 to 95% by
mole, relative to all acid components. Meanwhile, the ratio of the
acid component (B) is 0 to 15% by mole, preferably 0 to 12.5% by
mole, and more preferably 0 to 10% by mole, relative to the all
acid components. Such a composition ratio makes it possible to
obtain a resin for an oxygen-absorbing adhesive which is excellent
in oxygen-absorbing performance and adhesion, and is excellent in
solubility in an organic solvent.
[0045] The glass transition temperature of the resin for an
oxygen-absorbing adhesive of the present invention is -20.degree.
C. to 2.degree. C. (for example, -20.degree. C. to 0.degree. C.),
preferably in the range from -15.degree. C. to 2.degree. C., and
more preferably in the range from -12.degree. C. to 2.degree. C.,
in order to obtain sufficient oxygen-absorbing performance. If the
glass transition temperature exceeds the above-described range, the
mobility of the molecular chains is remarkably lowered after
curing, so that the oxygen-absorbing performance deteriorates. If
the glass transition temperature is below the above-described
range, the mobility is so high that inactivation reactions such as
disproportionation and recombination of radicals required to
initiate an auto-oxidation reaction tend to occur. Consequently,
there arises a possibility that the oxygen-absorbing performance
remarkably deteriorates especially at an initial stage. Therefore,
such a glass transition temperature is not preferable, when the
resin for an oxygen-absorbing adhesive of the present invention is
used in an adhesive.
[0046] The resin for an oxygen-absorbing adhesive of the present
invention further comprises a structural unit derived from a diol
component. Examples of the diol component include ethylene glycol,
diethylene glycol, triethylene glycol, polyethylene glycol,
propylene glycol, dipropylene glycol, polypropylene glycol,
trimethylene glycol, 1,3-butanediol, 1,4-butanediol,
3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol,
1,8-octanediol, 1,9-nonanediol, neopentyl glycol,
1,4-cyclohexanedimethanol, 2-phenylpropanediol,
2-(4-hydroxyphenyl)ethyl alcohol,
.alpha.,.alpha.-dihydroxy-1,3-diisopropylbenzene, o-xylene glycol,
m-xylene glycol, p-xylene glycol,
.alpha.,.alpha.-dihydroxy-1,4-diisopropylbenzene, hydroquinone,
4,4-dihydroxydiphenyl, naphthalenediol, derivatives thereof, and
the like. Preferred are aliphatic diols including, for example,
ethylene glycol, diethylene glycol, triethylene glycol,
1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, and further
preferred is 1,4-butanediol. When 1,4-butanediol is used, the
oxygen-absorbing performance of the resin is high, and further the
amount of degradation products generated during the auto-oxidation
is small. One kind of these diol components can be used alone, or
two or more kinds thereof can be used in combination.
[0047] The resin for an oxygen-absorbing adhesive of the present
invention may further comprise a structural unit derived from an
aromatic dicarboxylic acid other than phthalic acid, an aliphatic
dicarboxylic acid, an aliphatic hydroxycarboxylic acid, a
polyvalent alcohol, a polyvalent carboxylic acid, a derivative
thereof, or the like. Here, the term "derivative" includes esters,
acid anhydrides, acid halides, substituted compounds, oligomers,
and the like. Of these, an aliphatic dicarboxylic acid is
particularly preferable. One kind thereof can be used alone, or two
or more kind thereof can be used in combination. The glass
transition temperature of the obtained resin for an
oxygen-absorbing adhesive can be controlled easily by
copolymerization with the above-described further acid component,
and the oxygen-absorbing performance can be improved. Further, it
is also possible to control solubility in an organic solvent.
Moreover, the viscosity characteristics of an oxygen-absorbing
adhesive composition dissolved in a solvent can be modified by
introducing a polyvalent alcohol and a polyvalent carboxylic acid
and thus controlling the branching structure of the resin.
[0048] Examples of the aromatic dicarboxylic acid other than the
phthalic acid and the derivative thereof include
naphthalenedicarboxylic acids such as 2,6-naphthalenedicarboxylic
acid, anthracenedicarboxylic acids, derivatives thereof, and the
like.
[0049] Examples of the aliphatic dicarboxylic acid and the
derivative thereof include oxalic acid, malonic acid, succinic
acid, succinic anhydride, glutaric acid, adipic acid, pimelic acid,
suberic acid, azelaic acid, sebacic acid, undecanedioic acid,
dodecanedioic acid, 3,3-dimethylpentanedioic acid, derivatives
thereof, and the like. Of these examples, adipic acid, succinic
acid, and succinic anhydride are preferable, and succinic acid and
succinic anhydride are particularly preferable.
[0050] Examples of the aliphatic hydroxycarboxylic acid and the
derivative thereof include glycolic acid, lactic acid,
hydroxypivalic acid, hydroxycaproic acid, hydroxyhexanoic acid, and
derivatives thereof.
[0051] Examples of the polyvalent alcohol and the derivative
thereof include 1,2,3-propanetriol, sorbitol, 1,3,5-pentanetriol,
1,5,8-heptanetriol, trimethylolpropane, pentaerythritol,
3,5-dihydroxybenzyl alcohol, glycerin, and derivatives thereof.
[0052] Examples of the polyvalent carboxylic acid and the
derivative thereof include 1,2,3-propanetricarboxylic acid,
meso-butane-1,2,3,4-tetracarboxylic acid, citric acid, trimellitic
acid, pyromellitic acid, and derivatives thereof.
[0053] The ratio of the structural unit derived from the further
acid component is preferably 1 to 30% by mole, and more preferably
5 to 20% by mole, relative to the all acid components.
[0054] In addition, when a component having three or more
functional groups such as a polyvalent alcohol or a polyvalent
carboxylic acid is copolymerized, the ratio of the structural unit
derived from the component is preferably within 5% by mole relative
to the all acid components.
[0055] The resin for an oxygen-absorbing adhesive of the present
invention can be obtained by any polyester polycondensation method
known to those skilled in the art. For example, the method may be
interfacial polycondensation, solution polycondensation, melt
polycondensation, or solid-state polycondensation.
[0056] A polymerization catalyst is not necessarily required for
the synthesis of the resin for an oxygen-absorbing adhesive of the
present invention. However, it is possible to use, for example, an
ordinary polyester polymerization catalyst such as a
titanium-based, germanium-based, antimony-based, tin-based, or
aluminum-based polyester polymerization catalyst. Alternatively, it
is also possible to use a known polymerization catalyst such as a
nitrogen-containing basic compound, boric acid, a boric acid ester,
or an organic sulfonic acid-based compound.
[0057] Further, it is also possible to add various additives
including an anti-coloring agent, an antioxidant, and the like,
such as a phosphorus compound, for the polymerization. The addition
of an antioxidant makes it possible to reduce oxygen absorption
during the polymerization or subsequent processing, so that
deterioration in performance of the resin for an oxygen-absorbing
adhesive and the formation of a gel can be prevented.
[0058] The number average molecular weight of the resin for an
oxygen-absorbing adhesive of the present invention is preferably
500 to 100000, and more preferably 1000 to 20000. Meanwhile, a
preferred weight average molecular weight is 5000 to 200000, more
preferably 10000 to 100000, and further preferably 20000 to 90000.
If the molecular weights are below the above-described ranges, the
cohesive force, i.e., creep resistance of the resin deteriorates.
If the molecular weights exceed the above-described ranges,
deterioration in coatability occurs because of decrease in
solubility in an organic solvent or increase in solution viscosity.
Hence, such molecular weights are not preferable, when the resin
for an oxygen-absorbing adhesive of the present invention is used
in an adhesive. When the molecular weights are within the
above-described ranges, it is possible to obtain an
oxygen-absorbing adhesive resin composition which is excellent in
cohesive force, adhesion, and solubility in an organic solvent, and
which has viscosity characteristics preferable as those of an
adhesive solution.
[0059] Moreover, it is also possible to obtain a resin for an
oxygen-absorbing adhesive of the present invention with a higher
molecular weight by using a chain extender such as an organic
diisocyanate. Various known aromatic, aliphatic, or alicyclic
diisocyanates can be used as the organic diisocyanate-based chain
extender. Examples of the aromatic diisocyanates include
4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, and the
like. Examples of the aliphatic diisocyanates include hexamethylene
diisocyanate, xylylene diisocyanate, lysine diisocyanate, and the
like. Examples of the alicyclic diisocyanates include
cyclohexane-1,4-diisocyanate, isophorone diisocyanate,
dicyclohexylmethane-4,4'-diisocyanate, dimer diisocyanate obtained
by converting the carboxyl groups of dimer acid into isocyanate
groups, and the like. Further, these organic diisocyanates can also
be used in the form of a tri- or higher functional polyisocyanate
compound such as an adduct with trimethylolpropane or the like, an
isocyanurate compound, or a biuret compound. One kind of the
above-described organic isocyanates and polyisocyanate compounds
may be used alone, or two or more kinds thereof may be used in
combination.
[0060] One kind of resins for an oxygen-absorbing adhesive of the
present invention may be used alone, or two or more kinds thereof
may be used in combination.
[0061] The resin for an oxygen-absorbing adhesive of the present
invention is used with a curing agent as a two-part curable
oxygen-absorbing resin composition. A compound capable of curing
the resin by a reaction with functional groups of the
oxygen-absorbing polyester, such as carboxyl groups or hydroxy
groups, is preferably used as the curing agent. Examples thereof
include isocyanate-based, epoxy-based, melamine-based, amine-based,
carbodiimide-based, oxazoline-based, aziridine-based, organic
titanium-based, and organic silane-based curing agents, and the
like. In this case, it is preferable to use a compound having three
or more reactive functional groups as the curing agent, because the
cohesive force is improved by a cross-linking reaction. Moreover,
one kind of these curing agents may be used alone, or two or more
kinds thereof may be used in combination.
[0062] It is particularly preferable to prepare a urethane-based
adhesive by using an isocyanate-based curing agent, among the
above-described curing agents, because the adhesion strength and
the cohesive force are increased, and the urethane-based adhesive
is curable at a low temperature around room temperature. Any of the
organic diisocyanates and polyisocyanate compounds listed as the
chain extender can be used preferably as the isocyanate-based
curing agent. In particular, an aliphatic diisocyanate such as
hexamethylene diisocyanate or xylylene diisocyanate or an alicyclic
diisocyanate such as isophorone diisocyanate is preferable, and it
is preferable to use the organic diisocyanate in the form of a
three- or higher functional polyisocyanate compound such as an
adduct with trimethylolpropane or the like, an isocyanurate
compound, or a biuret compound.
[0063] Examples of the epoxy-based curing agent include
polypropylene glycol diglycidyl ether, polyethylene glycol
diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane
polyglycidyl ether, neopentyl glycol diglycidyl ether, sorbitol
polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol
polyglycidyl ether, pentaerythritol polyglycidyl ether,
1,6-hexanediol diglycidyl ether,
3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexenecarboxylate, and
the like.
[0064] Regarding the organic titanium-based curing agent, the
valence of the titanium is not limited, and a tetraalkoxytitanium
containing tetravalent titanium or a derivative thereof is
particularly preferable. Examples of the organic titanium-based
curing agent include titanium alkoxides such as titanium
tetramethoxide, titanium tetraethoxide, titanium tetraisopropoxide,
titanium tetra-n-butoxide, titanium tetra-2-ethylhexoxide, titanium
tetrastearoxide, trimethoxytitanium chloride, triethoxytitanium
chloride, ethyltrimethoxytitanium, methyltriethoxytitanium,
ethyltriethoxytitanium, diethyldiethoxytitanium,
phenyltrimethoxytitanium, and phenyltriethoxytitanium, as well as
titanium alkoxide derivatives such as polymers thereof; titanium
chelates such as diisopropoxytitanium bis(acetylacetonate),
titanium tetraacetylacetonate, diisopropoxytitanium
bis(octyleneglycolate), dioctyloxytitanium bis(octyleneglycolate),
diisopropoxytitanium bis(ethyl acetate), diisopropoxytitanium
bis(triethanolaminate), di-n-butoxytitanium bis(triethanolaminate),
titanium lactate, and dihydroxytitanium bislactate, as well as
derivatives thereof; and titanium acylates such as hydroxytitanium
stearate, tri-n-butoxytitanium stearate, and isopropoxytitanium
tristearate, as well as derivatives thereof such as polymers
thereof. However, the organic titanium-based curing agent is not
limited to these examples. In addition, of these organic
titanium-based curing agents, particularly preferred are titanium
alkoxides and derivative thereof, as well as titanium chelates, and
further preferred are titanium tetra-n-butoxide polymers with a
degree of polymerization of 4 to 10 and diisopropoxytitanium
bis(acetylacetonate).
[0065] The resin for an oxygen-absorbing adhesive of the present
invention can be dissolved in a solvent such as an organic solvent,
and used as an oxygen-absorbing adhesive resin composition.
Examples of the solvent include ethyl acetate, acetone, methyl
ethyl ketone, methyl isobutyl ketone, toluene, xylene, isopropanol,
and the like. In particular, ethyl acetate is generally used as a
solvent of an adhesive for dry lamination of flexible packaging,
because ethyl acetate causes relatively few odor troubles due to
residual solvent. Hence, a single solvent of ethyl acetate not
containing toluene, xylene, or the like is preferably used as the
solvent of the present invention, in view of industrial
application.
[0066] If necessary, various additives such as a silane coupling
agent, an antioxidant, an ultraviolet absorber, an anti-hydrolysis
agent, a fungicide, a curing catalyst, a thickener, a plasticizer,
a pigment, a filler, a polyester resin, and an epoxy resin can be
added to the two-part curable oxygen-absorbing resin composition of
the present invention, unless the object of the present invention
is adversely affected.
[0067] The two-part curable oxygen-absorbing resin composition of
the present invention can be used for the purpose of laminating
multiple films, as in the case of ordinary adhesives for dry
lamination. In particular, the two-part curable oxygen-absorbing
resin composition of the present invention can be suitably used for
laminating a film substrate having oxygen barrier property and a
sealant film having heat sealing property and oxygen gas
permeability. In this case, the structure of the laminate includes
an oxygen barrier substrate layer/a two-part curable
oxygen-absorbing resin composition layer/a sealant layer, from the
outer layer side. This structure is preferable because oxygen
permeating and penetrating from the outside can be blocked by the
oxygen barrier substrate, so that deterioration in oxygen-absorbing
performance of the two-part curable oxygen-absorbing resin
composition due to oxygen outside a container can be prevented, and
because the two-part curable oxygen-absorbing resin composition can
rapidly absorb oxygen inside the container through the oxygen
permeable sealant film.
[0068] Each of the film substrate and the sealant film having
oxygen barrier property may be constituted of a single layer or a
laminate. As the film substrate having oxygen barrier property, it
is preferable to use a biaxially oriented PET film, biaxially
oriented polyamide film, or biaxially oriented polypropylene film
having, as a barrier layer, a vapor-deposited thin film of a metal
or a metal oxide such as silica or alumina, or a barrier coating
layer mainly composed of a gas-barrier organic material such as a
polyvinyl alcohol-based resin, an ethylene-vinyl alcohol copolymer,
a polyacrylic acid-based resin, or a vinylidene chloride-based
resin, or the like. Moreover, an ethylene-vinyl alcohol copolymer
film, a poly(meta-xylylene adipamide) film, a polyvinylidene
chloride-based film, or a metal foil such as an aluminum foil is
also preferable. It is possible to use a laminate of substrates of
a single kind or substrates of two or more different kinds of these
film substrates having oxygen barrier property. In addition, it is
also preferable to use the film substrate having oxygen barrier
property after a biaxially oriented PET film, a biaxially oriented
polyamide film, a biaxially oriented polypropylene film,
cellophane, paper, or the like is laminated on the film
substrate.
[0069] Examples of the material of the sealant film include
low-density polyethylene, medium-density polyethylene, high-density
polyethylene, linear low-density polyethylene, linear
ultra-low-density polyethylene, polypropylene, poly-1-butene,
poly-4-methyl-1-pentene, cyclic olefin polymers, cyclic olefin
copolymers, polyolefins including random or block copolymers of
.alpha.-olefins such as ethylene, propylene, 1-butene, and
4-methyl-1-pentene and the like, ethylene-vinyl acetate copolymers,
ethylene-(meth)acrylic acid copolymers, ionically cross-linked
products (ionomers) thereof, ethylene-vinyl compound copolymers
such as ethylene-methyl methacrylate copolymers, polyesters having
heat sealing property such as PET, A-PET, PETG, and PBT, amorphous
nylon, and the like. A blend of two kinds or more of these
materials can also be used, or a laminate of a single material or
different materials thereof may be used.
[0070] A known dry laminator can be used to laminate multiple film
substrates by using the two-part curable oxygen-absorbing resin
composition of the present invention. With this dry laminator, it
is possible to carry out a series of laminating processes including
application of the two-part curable oxygen-absorbing resin
composition onto a barrier film substrate, solvent vaporization
with a drying oven, and lamination with a sealant film by nip rolls
heated at 50 to 120.degree. C. The amount of the two-part curable
oxygen-absorbing resin composition applied is 0.1 to 30 g/m.sup.2,
preferably 1 to 15 g/m.sup.2, and further preferably 2 to 10
g/m.sup.2. It is preferable to age an oxygen-absorbing laminated
film laminated by using the two-part curable oxygen-absorbing resin
composition at a temperature around room temperature, for example,
at 10 to 60.degree. C., in order to promote the curing reaction.
The curing is caused by crystallization of the resin for an
oxygen-absorbing adhesive and cross-linking reaction with the
curing agent such as an organic diisocyanate, and is preferable
because the curing results in improvement in adhesion strength and
cohesive force.
[0071] Note that the aging is preferably conducted in the absence
of oxygen or under blocking of oxygen by tightly sealing the
oxygen-absorbing laminated film with, for example, an
oxygen-impermeable bag or the like. Thus, deterioration in
oxygen-absorbing performance due to oxygen in the air can be
prevented during the aging.
[0072] Moreover, the resin for an oxygen-absorbing adhesive of the
present invention can also be used as a solventless adhesive,
without being dissolved in a solvent. In this case, the
oxygen-absorbing laminated film can be obtained by using a known
non-solvent laminator.
[0073] Further, the resin for an oxygen-absorbing adhesive of the
present invention can be used not only in adhesive applications,
but also in paint applications, and can be applied as coating films
for various films and the like.
[0074] An oxygen-absorbing laminated film laminated by using the
resin for an oxygen-absorbing adhesive of the present invention can
be suitably used for bag-shaped containers with various shapes and
lid members for cup or tray containers. Examples of the bag-shaped
containers include three-side or four-side sealed flat pouches,
pouches with gusset, standing pouches, pillow packaging bags, and
the like.
[0075] An oxygen-absorbing container in which the oxygen-absorbing
laminated film is used in at least a part of the oxygen-absorbing
container effectively blocks oxygen permeating from the outside of
the container, and absorbs oxygen remaining in the container. For
this reason, such an oxygen-absorbing container is useful as a
container which improves the shelf-life by keeping the oxygen
concentration in the container at a low level for a long period,
and thus preventing deterioration in quality of a content due to
oxygen.
[0076] In particular, examples of contents susceptible to
deterioration in the presence of oxygen include foods such as
coffee beans, tea leaves, snacks, rice confectionery products, raw
or semi-raw confectionery products, fruits, nuts, vegetables, fish
or meat products, paste products, dried fish, smoked foods,
Tsukudani (Japanese simmered foods), raw rice, cooked rice food
products, infant foods, jams, mayonnaise, ketchup, edible oils,
dressings, sources, and dairy products; beverages such as beers,
wines, fruit juices, green teas, and coffees; and other contents
such as pharmaceuticals, cosmetics, electronic components; and the
like. However, the contents are not limited to these examples.
EXAMPLES
[0077] Hereinafter, the present invention is described more
specifically on the basis of Examples. Values were measured by the
following methods.
(1) Number Average Molecular Weight (Mn) and Weight Average
Molecular Weight (Mw)
[0078] Measurement was conducted by gel permeation chromatography
(GPC, an HLC-8120 model GPC manufactured by Tosoh Corporation) in
terms of polystyrene. Chloroform was used as the solvent.
(2) Composition Ratio of Monomer Units in Resin for
Oxygen-Absorbing Adhesive
[0079] By nuclear magnetic resonance spectroscopy (1H-NMR, EX270
manufactured by JEOL DATUM Ltd.), the composition ratio of acid
components in a resin was calculated from the area ratio of signals
of benzene ring protons (8.1 ppm) derived from terephthalic acid,
benzene ring protons (8.7 ppm) derived from isophthalic acid,
methylene protons (2.6 ppm) derived from succinic acid, methylene
protons (2.3 ppm) derived from adipic acid, methylene protons (4.3
to 4.4 ppm) adjacent to ester groups derived from terephthalic acid
and isophthalic acid, and methylene protons (4.1 to 4.2 ppm)
adjacent to ester groups derived from methyltetrahydrophthalic
anhydride, succinic acid, adipic acid, and sebacic acid. Deuterated
chloroform containing tetramethylsilane as a reference substance
was used as the solvent.
[0080] Here, the composition ratio of acid components in each resin
was almost equivalent to the feed amounts (molar ratio) of monomers
used for polymerization.
(3) Glass Transition Temperature; Tg
[0081] Measurement was conducted by using a differential scanning
calorimeter (DSC6220 manufactured by Seiko Instruments Inc.) under
a nitrogen stream at a rate of temperature rise of 10.degree.
C./minute.
(4) Amount of Oxygen Absorbed
[0082] A test piece of 2 cm.times.10 cm cut from a laminated film
was placed in an oxygen impermeable steel foil laminate cup with an
internal volume of 85 cm.sup.3, tightly sealed with an aluminum
foil laminate film lid by heat sealing, and was stored under an
atmosphere of 22.degree. C. The oxygen concentration in the cup
after a 14-day storage was measured with a micro gas chromatograph
(M200 manufactured by Agilent Technologies, Inc.), and the amount
of oxygen absorbed per square centimeter of the film was
calculated. An oxygen-absorbing performance with 0.015 ml/cm.sup.2
or more in a 7-day period and 0.025 ml/cm.sup.2 or more in a 14-day
period was evaluated as good (G).
(5) Creep Resistance
[0083] A T-peel creep test between aluminum foil and LDPE was
conducted under an atmosphere of 40.degree. C. with a test piece
width of 25 mm and a load of 50 g, and an peel length (unit: mm)
was measured 2 hours later. A test piece with 20 mm or more was
evaluated as poor (P), and a test piece with less than 20 mm was
evaluated as good (G).
(6) Overall Evaluation
[0084] A case where both the oxygen-absorbing performance and the
creep resistance were evaluated as G was evaluated as good (G), and
a case where either or both of the oxygen-absorbing performance and
the creep resistance were evaluated as P was evaluated as poor
(P).
Example 1
[0085] Into a 3-L separable flask equipped with a stirrer, a
nitrogen inlet, and a Dean-Stark water separator, 399 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) containing 45% by mole
of 4-methyl-.DELTA..sup.3-tetrahydrophthalic anhydride and 21% by
mole of cis-3-methyl-.DELTA..sup.4-tetrahydrophthalic anhydride as
the acid component (A), 50 g of terephthalic acid (manufactured by
Wako Pure Chemical Industries, Ltd.) as the acid component (B), 30
g of succinic anhydride (manufactured by Wako Pure Chemical
Industries, Ltd.) as the further acid component, 379 g of
1,4-butanediol (manufactured by manufactured by Wako Pure Chemical
Industries, Ltd.) as the diol component, 300 ppm of isopropyl
titanate (manufactured by KISHIDA CHEMICAL Co., Ltd.) as the
polymerization catalyst, and 20 ml of toluene were introduced.
Then, a reaction was allowed to proceed for approximately 6 hours
in a nitrogen atmosphere at 150.degree. C. to 200.degree. C., while
the produced water was being removed. Subsequently, toluene was
removed from the reaction system, and then polymerization was
conducted under a reduced pressure of 0.1 kPa at 200 to 220.degree.
C. for approximately 3 hours. Thus, a resin for an oxygen-absorbing
adhesive was obtained. Here, the Mn was approximately 4400, the Mw
was 57200, and the Tg was -2.2.degree. C.
[0086] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution A).
Curing Agent A (CAT-RT1 manufactured by Toyo-Morton, Ltd., an
alicyclic isocyanate-based curing agent with a solid content
concentration of 70%) in an amount of 10 phr (parts per hundred
resin) in terms of solid content was mixed with this Base Solution
A, and the mixture was shaken. Thus, an oxygen-absorbing adhesive
solution was prepared. The prepared adhesive solution was applied
with a #18 bar coater onto an aluminum foil surface of a laminated
film including a biaxially oriented PET film (film thickness: 12
.mu.m)/an aluminum foil (film thickness: 7 .mu.m) and being
prepared by a dry lamination method. The solvent contained in the
adhesive was evaporated with hot air of a hair dryer, and then the
laminated film was passed between hot rolls at 70.degree. C., with
the surface of the laminated film on which the adhesive was applied
and a corona-treated surface of a 30-.mu.m LDPE film (AJ-3
manufactured by TAMAPOLY CO., LTD.) being faced to each other.
Thus, an oxygen-absorbing laminated film was obtained which was
constituted of the biaxially oriented PET film (film thickness: 12
.mu.m)/the aluminum foil (film thickness: 7 .mu.m)/the
oxygen-absorbing resin composition (adhesive) (film thickness: 4
.mu.m)/the LDPE.
[0087] The obtained oxygen-absorbing laminated film was stored at
35.degree. C. under a nitrogen atmosphere for 5 days, and then
subjected to the evaluation of the amount of oxygen absorbed and
the evaluation of the creep resistance. Table 1 shows the
results.
Example 2
[0088] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent A in an amount of 20 phr in terms of solid content
with Base Solution A, followed by shaking. An oxygen-absorbing film
was prepared by using the prepared adhesive solution in the same
manner as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 3
[0089] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent B (A-50 manufactured by Mitsui Chemicals, Inc., an
alicyclic and aliphatic mixture isocyanate-based curing agent with
a solid content concentration of 75%) in an amount of 10 phr in
terms of solid content with Base Solution A, followed by shaking.
An oxygen-absorbing film was prepared by using the prepared
adhesive solution in the same manner as in Example 1, and then
subjected to the evaluations after storage. Table 1 shows the
results.
Example 4
[0090] A resin for a oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 3 hours in the same
manner as in Example 1, except that 399 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 25 g of terephthalic acid (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the acid component (B), 45 g
of succinic anhydride (Wako Pure Chemical Industries, Ltd.) was
used as the further acid component, 379 g of 1,4-butanediol
(manufactured by Wako Pure Chemical Industries, Ltd.) was used as
the diol component, 300 ppm of isopropyl titanate (manufactured by
KISHIDA CHEMICAL Co., Ltd.) was used as the polymerization
catalyst, and 20 ml of toluene was used. Here, the Mn was
approximately 4600, the Mw was 56900, and the Tg was -5.3.degree.
C.
[0091] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution B). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution B, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 5
[0092] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent A in an amount of 20 phr in terms of solid content
with Base Solution B, followed by shaking. An oxygen-absorbing film
was prepared by using the prepared adhesive solution in the same
manner as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 6
[0093] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent B in an amount of 10 phr in terms of solid content
with Base Solution B, followed by shaking. An oxygen-absorbing film
was prepared by using the prepared adhesive solution in the same
manner as in Example 1, and then was subjected to the evaluations
after storage. Table 1 shows the results.
Example 7
[0094] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 3 hours in the same
manner as in Example 1, except that 399 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 60 g of succinic anhydride (manufactured by Wako
Pure Chemical Industries, Ltd.) was used as the further acid
component, 379 g of 1,4-butanediol (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the diol component, 300 ppm
of isopropyl titanate (manufactured by KISHIDA CHEMICAL Co., Ltd.)
was used as the polymerization catalyst, and 20 ml of toluene was
used. Here, the Mn was approximately 3800, the Mw was 57800, and
the Tg was -8.5.degree. C.
[0095] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution C). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution C, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 8
[0096] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent A in an amount of 20 phr in terms of solid content
with Base Solution C, followed by shaking. An oxygen-absorbing film
was prepared by using the prepared adhesive solution in the same
manner as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 9
[0097] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent B in an amount of 10 phr in terms of solid content
with Base Solution C, followed by shaking. An oxygen-absorbing film
was prepared by using the prepared adhesive solution in the same
manner as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 10
[0098] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 3 hours in the same
manner as in Example 1, except that 399 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 50 g of isophthalic acid (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the acid component (B), 30 g
of succinic anhydride (manufactured by Wako Pure Chemical
Industries, Ltd.) was used as the further acid component, 379 g of
1,4-butanediol (manufactured by Wako Pure Chemical Industries,
Ltd.) was used as the diol component, 300 ppm of isopropyl titanate
(manufactured by KISHIDA CHEMICAL Co., Ltd.) was used as the
polymerization catalyst, and 20 ml of toluene was used. Here, the
Mn was approximately 4100, the Mw was 41900, and the Tg was
-2.9.degree. C.
[0099] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution D). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution D, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 11
[0100] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 3 hours in the same
manner as in Example 1, except that 399 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 50 g of terephthalic acid (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the acid component (B), 44 g
of adipic acid (manufactured by Wako Pure Chemical Industries,
Ltd.) was used as the further acid component, 379 g of
1,4-butanediol (manufactured by Wako Pure Chemical Industries,
Ltd.) was used as the diol component, 300 ppm of isopropyl titanate
(manufactured by KISHIDA CHEMICAL Co., Ltd.) was used as the
polymerization catalyst, and 20 ml of toluene was used. Here, the
Mn was approximately 4600, the Mw was 53200, and the Tg was
-6.5.degree. C.
[0101] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution E). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution E, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 12
[0102] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 3 hours in the same
manner as in Example 1, except that 449 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 25 g of terephthalic acid (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the acid component (B), 15 g
of succinic anhydride (manufactured by Wako Pure Chemical
Industries, Ltd.) was used as the further acid component, 379 g of
1,4-butanediol (manufactured by Wako Pure Chemical Industries,
Ltd.) was used as the diol component, 300 ppm of isopropyl titanate
(manufactured by KISHIDA CHEMICAL Co., Ltd.) was used as the
polymerization catalyst, and 20 ml of toluene was used. Here, the
Mn was approximately 4000, the Mw was 51900, and the Tg was
-1.5.degree. C.
[0103] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution F). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution F, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 13
[0104] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 3 hours in the same
manner as in Example 1, except that 449 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 30 g of succinic anhydride (manufactured by Wako
Pure Chemical Industries, Ltd.) was used as the further acid
component, 351 g of 1,4-butanediol (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the diol component, 300 ppm
of isopropyl titanate (manufactured by KISHIDA CHEMICAL Co., Ltd.)
was used as the polymerization catalyst, and 20 ml of toluene was
used. Here, the Mn was approximately 3700, the Mw was 56800, and
the Tg was -4.2.degree. C.
[0105] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution G). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution G, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 14
[0106] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent B in an amount of 10 phr in terms of solid content
with Base Solution G, followed by shaking. An oxygen-absorbing film
was prepared by using the prepared adhesive solution in the same
manner as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 15
[0107] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 2 hours in the same
manner as in Example 1, except that 449 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 50 g of terephthalic acid (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the acid component (B), 379
g of 1,4-butanediol (manufactured by Wako Pure Chemical Industries,
Ltd.) was used as the diol component, 300 ppm of isopropyl titanate
(manufactured by KISHIDA CHEMICAL Co., Ltd.) was used as the
polymerization catalyst, and 20 ml of toluene was used. Here, the
Mn was approximately 3500, the Mw was 24400, and the Tg was
0.2.degree. C.
[0108] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution H). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution H, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Example 16
[0109] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 2 hours in the same
manner as in Example 1, except that 349 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200 of
Hitachi Chemical Co., Ltd.) was used as the acid component (A), 75
g of terephthalic acid (Wako Pure Chemical Industries, Ltd.) was
used as the acid component (B), 45 g of succinic anhydride (Wako
Pure Chemical Industries, Ltd.) was used as the further acid
component, 379 g of 1,4-butanediol (Wako Pure Chemical Industries,
Ltd.) was used as the diol component, 300 ppm of isopropyl titanate
(KISHIDA CHEMICAL Co., Ltd.) was used as the polymerization
catalyst, and 20 ml of toluene was used. Here, the Mn was
approximately 4900, the Mw was 50300, and the Tg was -3.8.degree.
C.
[0110] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution J). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution J, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Comparative Example 1
[0111] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 2 hours in the same
manner as in Example 1, except that 349 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 150 g of terephthalic acid (manufactured by Wako
Pure Chemical Industries, Ltd.) was used as the acid component (B),
487 g of 1,4-butanediol (manufactured by Wako Pure Chemical
Industries, Ltd.) was used as the diol component, 300 ppm of
isopropyl titanate (manufactured by KISHIDA CHEMICAL Co., Ltd.) was
used as the polymerization catalyst, and 20 ml of toluene was used.
Here, the Mn was approximately 4800, the Mw was 47500, and the Tg
was 5.7.degree. C.
[0112] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution K). An
oxygen-absorbing film was prepared in the same manner as in Example
1, except that no curing agent was added to this Base Solution K.
The oxygen-absorbing film was then subjected to the evaluations
after storage. Table 1 shows the results.
Comparative Example 2
[0113] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 2 hours in the same
manner as in Example 1, except that 399 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 100 g of terephthalic acid (manufactured by Wako
Pure Chemical Industries, Ltd.) was used as the acid component (B),
432 g of 1,4-butanediol (manufactured by Wako Pure Chemical
Industries, Ltd.) was used as the diol component, 300 ppm of
isopropyl titanate (manufactured by KISHIDA CHEMICAL Co., Ltd.) was
used as the polymerization catalyst, and 20 ml of toluene was used.
Here, the Mn was approximately 4300, the Mw was 46000, and the Tg
was 3.8.degree. C.
[0114] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution L). An
oxygen-absorbing film was prepared in the same manner as in Example
1, except that no curing agent was added to this Base Solution L.
The oxygen-absorbing film was then subjected to the evaluations
after storage. Table 1 shows the results.
Comparative Example 3
[0115] An oxygen-absorbing film was prepared in the same manner as
in Example 1, except that no curing agent was added to Base
Solution H prepared in Example 15. The oxygen-absorbing film was
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 4
[0116] An oxygen-absorbing film was prepared in the same manner as
in Example 1, except that no curing agent was added to Base
Solution A prepared in Example 1. The oxygen-absorbing film was
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 5
[0117] An oxygen-absorbing film was prepared in the same manner as
in Example 1, except that no curing agent was added to Base
Solution B prepared in Example 4. The oxygen-absorbing film was
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 6
[0118] An oxygen-absorbing film was prepared in the same manner as
in Example 1, except that no curing agent was added to Base
Solution C prepared in Example 7. The oxygen-absorbing film was
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 7
[0119] An oxygen-absorbing film was prepared in the same manner as
in Example 1, except that no curing agent was added to Base
Solution G prepared in Example 13. The oxygen-absorbing film was
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 8
[0120] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent A in an amount of 10 phr in terms of solid content
with Base Solution K prepared in Comparative Example 1, followed by
shaking. An oxygen-absorbing film was prepared by using the
prepared adhesive solution in the same manner as in Example 1, and
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 9
[0121] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent B in an amount of 10 phr in terms of solid content
with Base Solution K prepared in Comparative Example 1, followed by
shaking. An oxygen-absorbing film was prepared by using the
prepared adhesive solution in the same manner as in Example 1, and
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 10
[0122] An oxygen-absorbing adhesive solution was prepared by mixing
Curing Agent A in an amount of 10 phr in terms of solid content
with Base Solution L prepared in Comparative Example 2, followed by
shaking. An oxygen-absorbing film was prepared by using the
prepared adhesive solution in the same manner as in Example 1, and
then subjected to the evaluations after storage. Table 1 shows the
results.
Comparative Example 11
[0123] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 2 hours in the same
manner as in Example 1, except that 249 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 150 g of terephthalic acid (manufactured by Wako
Pure Chemical Industries, Ltd.) was used as the acid component (B),
60 g of succinic anhydride (manufactured by Wako Pure Chemical
Industries, Ltd.) was used as the further acid component, 459 g of
1,4-butanediol (manufactured by Wako Pure Chemical Industries,
Ltd.) was used as the diol component, 300 ppm of isopropyl titanate
(manufactured by KISHIDA CHEMICAL Co., Ltd.) was used as the
polymerization catalyst, and 20 ml of toluene was used. Here, the
Mn was approximately 5100, the Mw was 36700, and the Tg was
-3.4.degree. C.
[0124] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution M). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent A in an amount of 10 phr in terms of solid content with this
Base Solution M, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Comparative Example 12
[0125] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 4 hours in the same
manner as in Example 1, except that 399 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 121 g of sebacic acid (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the further acid component,
351 g of 1,4-butanediol (manufactured by Wako Pure Chemical
Industries, Ltd.) was used as the diol component, 300 ppm of
isopropyl titanate (manufactured by KISHIDA CHEMICAL Co., Ltd.) was
used as the polymerization catalyst, and 20 ml of toluene was used.
Here, the Mn was approximately 3700, the Mw was 27000, and the Tg
was -25.1.degree. C.
[0126] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution N). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent B in an amount of 10 phr in terms of solid content with this
Base Solution N, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
Comparative Example 13
[0127] A resin for an oxygen-absorbing adhesive was obtained by
conducting polymerization for approximately 3 hours in the same
manner as in Example 1, except that 449 g of a
methyltetrahydrophthalic anhydride isomer mixture (HN-2200
manufactured by Hitachi Chemical Co., Ltd.) was used as the acid
component (A), 30 g of succinic anhydride (manufactured by Wako
Pure Chemical Industries, Ltd.) was used as the further acid
component, 461 g of 1,6-hexanediol (manufactured by Wako Pure
Chemical Industries, Ltd.) was used as the diol component, 300 ppm
of isopropyl titanate (manufactured by KISHIDA CHEMICAL Co., Ltd.)
was used as the polymerization catalyst, and 20 ml of toluene was
used. Here, the Mn was approximately 6000, the Mw was 67000, and
the Tg was -23.6.degree. C.
[0128] The obtained resin for an oxygen-absorbing adhesive was
dissolved in ethyl acetate at a concentration of 20% by weight
(hereinafter, this solution is referred to as Base Solution O). An
oxygen-absorbing adhesive solution was prepared by mixing Curing
Agent B in an amount of 10 phr in terms of solid content with this
Base Solution O, followed by shaking. An oxygen-absorbing film was
prepared by using the prepared adhesive solution in the same manner
as in Example 1, and then subjected to the evaluations after
storage. Table 1 shows the results.
TABLE-US-00001 TABLE 1 Constitution of resin % by mole Acid
component Curing agent Oxygen-absorbing performance Acid Acid
component (B) Further acid component Added 7-day 14-day component
Terephthalic Isophthalic Succinic Adipic Sebacic Diol component Tg
amount period period Creep Resistance Overall (A) acid acid acid
acid acid 1,4-Butanediol 1,6-Hexanediol .degree. C. Kind phr ml/cm2
ml/cm2 Evaluation mm Evaluation evaluation Example 1 80 10 -- 10 --
-- 100 -- -2.2 Curing Agent A 10 0.025 0.029 G 0 G G Example 2 20
0.022 0.025 G 0 G G Example 3 Curing Agent B 10 0.027 0.033 G 0 G G
Example 4 80 5 -- 15 -- -- 100 -- -5.3 Curing Agent A 10 0.028
0.036 G 0 G G Example 5 20 0.027 0.033 G 0 G G Example 6 Curing
Agent B 10 0.028 0.035 G 0 G G Example 7 80 -- -- 20 -- -- 100 --
-8.5 Curing Agent A 10 0.034 0.038 G 0 G G Example 8 20 0.030 0.034
G 0 G G Example 9 Curing Agent B 10 0.030 0.040 G 0 G G Example 10
80 -- 10 10 -- -- 100 -- -2.9 Curing Agent A 10 0.026 0.030 G 0 G G
Example 11 80 10 -- -- 10 -- 100 -- -6.5 Curing Agent A 10 0.027
0.034 G 0 G G Example 12 90 5 -- 5 -- -- 100 -- -1.5 Curing Agent A
10 0.025 0.030 G 0 G G Example 13 90 -- -- 10 -- -- 100 -- -4.2
Curing Agent A 10 0.030 0.033 G 0 G G Example 14 Curing Agent B 10
0.031 0.037 G 0 G G Example 15 90 10 -- -- -- -- 100 -- 0.2 Curing
Agent A 10 0.023 0.026 G 0 G G Example 16 70 15 -- 15 -- -- 100 --
-3.8 Curing Agent A 10 0.024 0.030 G 0 G G Comp. Ex. 1 70 30 -- --
-- -- 100 -- 5.7 -- -- 0.027 0.032 G >30 P P Comp. Ex. 2 80 20
-- -- -- -- 100 -- 3.8 -- -- 0.018 0.035 G >30 P P Comp. Ex. 3
90 10 -- -- -- -- 100 -- 0.2 -- -- 0.021 0.044 G >30 P P Comp.
Ex. 4 80 10 -- 10 -- -- 100 -- -2.2 -- -- 0.016 0.036 G >30 P P
Comp. Ex. 5 80 5 -- 15 -- -- 100 -- -5.3 -- -- 0.014 0.032 P >30
P P Comp. Ex. 6 80 -- -- 20 -- -- 100 -- -8.5 -- -- 0.002 0.006 P
>30 P P Comp. Ex. 7 90 -- -- 10 -- -- 100 -- -4.2 -- -- 0.001
0.003 P >30 P P Comp. Ex. 8 70 30 -- -- -- -- 100 -- 5.7 Curing
Agent A 10 0.012 0.016 P 0 G P Comp. Ex. 9 Curing Agent B 10 0.011
0.017 P 0 G P Comp. Ex. 10 80 20 -- -- -- -- 100 -- 3.8 Curing
Agent A 10 0.014 0.020 P 0 G P Comp. Ex. 11 50 30 -- 20 -- -- 100
-- -3.4 Curing Agent A 10 0.013 0.018 P 0 G P Comp. Ex. 12 80 -- --
-- -- 20 100 -- -25.1 Curing Agent B 10 0.008 0.016 P 0 G P Comp.
Ex. 13 90 -- -- 10 -- -- -- 100 -23.6 Curing Agent B 10 0.012 0.022
P 0 G P
INDUSTRIAL APPLICABILITY
[0129] A flexible packaging material having excellent oxygen
removal performance can be easily produced by using an
oxygen-absorbing adhesive containing the resin for an
oxygen-absorbing adhesive of the present invention and a curing
agent blended therein as an alternative to a conventional adhesive
for dry lamination. This oxygen-absorbing flexible packaging
material makes it possible to keep for long periods the qualities
of foods, pharmaceuticals, electronic components, and the like
which are sensitive to oxygen.
* * * * *