JP2007119606A - Oxygen-absorbing resin composition, oxygen-absorbing film, and oxygen-absorbing multilayered product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen-absorbing resin composition that exhibits excellent oxygen absorbability at room temperature, has a low metal content and generates odors a little at the time of oxygen absorption, an oxygen-absorbing film comprised of the oxygen-absorbing resin composition, and an oxygen-absorbing multilayered product comprising an oxygen-absorbing layer comprised of the oxygen-absorbing resin composition. <P>SOLUTION: The oxygen-absorbing resin composition comprises a resin (A) bearing a C-H bond having a bond dissociation energy of at most 3.70 eV and a resin (B) bearing a C-H bond having a bond dissociation energy of more than 3.70 eV and not more than 4.20 eV. The resin (A) is preferably a cyclized product of a conjugated diene polymer and is more preferably one having an unsaturated bond reduction rate of at most 60%. The resin (B) is preferably a cyclic olefin resin. The oxygen-absorbing film is comprised of the oxygen-absorbing resin composition. The oxygen-absorbing multilayered product comprises an oxygen-absorbing layer comprised of the oxygen-absorbing resin composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oxygen-absorbing resin composition excellent in oxygen-absorbing property, an oxygen-absorbing film comprising the oxygen-absorbing resin composition, and an oxygen comprising an oxygen-absorbing layer comprising the oxygen-absorbing resin composition. The present invention relates to an absorbent multilayer body. More specifically, an oxygen-absorbing resin composition having an excellent oxygen absorption amount and oxygen absorption rate at room temperature and less odor after oxygen absorption, an oxygen-absorbing film comprising the oxygen-absorbing resin composition, and the oxygen-absorbing resin composition The present invention relates to an oxygen-absorbing multilayer body having an oxygen-absorbing layer made of a material.

Foods, beverages, pharmaceuticals, and the like are deteriorated in quality due to oxygen, so that they are required to be stored in the absence of oxygen or under extremely low oxygen conditions.
Therefore, nitrogen is also filled in containers or packages for storing food, beverages, pharmaceuticals, etc., but for example, there is a problem that costs increase during manufacturing, once air is opened, air flows in from the outside. There is a problem that it becomes impossible to prevent quality degradation of the product. Therefore, various studies have been made to remove oxygen from the system by absorbing oxygen remaining in the container or package.

  Conventionally, as a method of removing oxygen in a container or a package, a method of arranging a separate sachet containing an oxygen absorbent mainly composed of iron powder is widely used. However, although this method is low-cost and has a high oxygen absorption rate, there are inconveniences when a metal detector is used for detecting foreign matter or when a microwave oven is applied while packaging.

In view of this, in the case of a resin container or packaging material, studies have been made to give oxygen or absorptivity to the container or packaging material itself.
For example, an oxygen absorbent comprising a polyterpene such as poly (α-pinene), poly (β-pinene) and poly (dipentene), and a transition metal salt such as cobalt neodecanoate and cobalt oleate which act as an oxygen absorption catalyst. It has been proposed to use (Patent Document 1).
It has also been proposed to use an oxygen absorbent comprising a conjugated diene polymer such as polyisoprene and 1,2-polybutadiene and a transition metal salt (Patent Document 2).
Furthermore, it has been proposed to use an oxygen absorbent comprising a copolymer of ethylene and cyclopentene and a transition metal salt (Patent Document 3).

  However, each of the compositions disclosed in these patent documents has a problem that oxygen absorption performance is not sufficient and a unique odor which is considered to be a byproduct of the oxygen scavenging reaction is left in the packaging container. In addition, since both of them contain transition metals, the polymer deteriorates as the oxygen absorption reaction proceeds, the mechanical strength of the packaging material is significantly reduced, and the transition metal salts are further colored. It is difficult to apply depending on the application.

JP-T-2001-507045 JP 2003-71992 A Japanese translation of PCT publication No. 2003-504042

  Accordingly, an object of the present invention is to provide an oxygen-absorbing resin composition that is excellent in oxygen absorption and oxygen absorption rate at room temperature, does not require the inclusion of metal, and has a low odor during oxygen absorption, and this oxygen-absorbing resin composition. It is to provide an oxygen-absorbing multilayer body comprising an oxygen-absorbing film and an oxygen-absorbing layer comprising the oxygen-absorbing resin composition.

As a result of intensive studies to solve the above problems, the present inventor has found that an oxygen absorbent containing a conjugated diene polymer cyclized product as an active ingredient has high oxygen absorptivity without adding a transition metal salt as a catalyst. In addition, the present inventors have found that the mechanical strength is kept high even after absorbing oxygen, and proposed an oxygen absorbent containing a conjugated diene polymer cyclized product as an active ingredient (Japanese Patent Laid-Open No. 2005-186060).
The present inventor has been researching on oxygen absorbers, but by combining a conjugated diene polymer cyclized product constituting the oxygen absorber with a resin having a specific structure, oxygen absorption (oxygen absorption amount and oxygen The absorption rate) is further improved, the odor after oxygen absorption is further reduced, and the mechanical strength of the resin composition can be improved. Based on this finding, C—H having a specific dissociation energy is added. The inventors came up with a combination of the two types of resins contained, and further researched to complete the present invention.

Thus, according to the present invention, a resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less and a resin having a C—H bond having a bond dissociation energy of more than 3.70 eV and 4.20 eV or less ( An oxygen-absorbing resin composition comprising B) is provided.
In the oxygen-absorbing resin composition of the present invention, the resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less is preferably a conjugated diene polymer cyclized product.
The conjugated diene polymer cyclized product preferably has an unsaturated bond reduction rate of 60% or less.
In the oxygen-absorbing resin composition of the present invention, the resin (B) having a C—H bond having a bond dissociation energy of more than 3.70 eV and not more than 4.20 eV is preferably a cyclic olefin resin.
Moreover, according to this invention, the oxygen absorptive film which consists of the said oxygen absorptive resin composition is provided.
Furthermore, according to this invention, the oxygen absorptive multilayer body which has an oxygen absorptive layer which consists of the said oxygen absorptive resin composition is provided.
The oxygen-absorbing multilayer body preferably further includes at least a gas barrier material layer.

Unlike the conventional oxygen absorbent, the oxygen-absorbing resin composition of the present invention does not need to contain a metal compound that serves as a catalyst for the oxygen absorption reaction. The oxygen-absorbing resin composition of the present invention does not require such a catalyst, has a large oxygen absorption amount per film weight, and has a high oxygen absorption rate per unit time / film unit area. Can demonstrate its sexuality.
Furthermore, the oxygen-absorbing resin composition of the present invention can reduce the amount of odor after oxygen absorption without reducing the amount of oxygen absorption due to its oxygen absorption mechanism.
The oxygen-absorbing film and oxygen-absorbing multilayer body of the present invention obtained by using this oxygen-absorbing resin composition have excellent oxygen-absorbing properties at room temperature and do not cause a problem of residual odor. It is suitable as a packaging material for products, pharmaceuticals, cosmetics and the like.

The oxygen-absorbing resin composition of the present invention includes a resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less and a C—H bond having a bond dissociation energy of more than 3.70 eV and 4.20 eV or less. And a resin (B) having
In the present invention, “the resin having a C—H bond having a bond dissociation energy of 3.70 eV or less” means “the bond dissociation energy having the lowest bond dissociation energy among all the C—H bonds possessed by the resin”. 3.70 eV or less ".

The bond dissociation energy of a certain C—H bond in the resin is based on the assumption that the resin is composed of repeating units containing the C—H bond, and methyl groups are bonded to both ends of the repeating unit. About a model, it can obtain | require using the following formula.
Bond dissociation energy = E (R ·) + E (H ·) −E (R−H)
Here, E (R.), E (H.), And E (R-H) are the electron energy of the radical after bond dissociation, the electron energy of the hydrogen radical, and the electron of the RH bond before bond dissociation, respectively. Energy.
For the calculation, a DMol3 module in MS Modeling v3.2 manufactured by Accelrys, which is a density functional method (see [1] and [2] below) program, is used, and HCTH (see [3] below) is used as the functional. As the basis function, DND (see [4] below) was used.
[1] Hohenberg, P .; Kohn, W .; Phys. Rev. B, 136, 864-871 (1964).
[2] Kohn, W. et al. Sham, L .; J. et al. Phys. Rev. A, 140, 1133-1138 (1965).
[3] Boese, A .; D. Handy, N .; C. , J. et al. Chem. Phys. 114, 5497 (2001).
[4] Delley, B.M. J. et al. Chem. Phys. , 92, 508 (1990).

In formula (1) of the conjugated diene polymer cyclized product obtained by this method, the bond dissociation energy of the intracyclic C—H bond (allylic carbon-hydrogen) shown in bold is 3.70 eV.
The hydrogen bond of 1,4-polyisoprene polymer and the dissociation energy of the C—H bond shown in bold in the ethylene-norbornene copolymer determined by this method are represented by formulas (2) and (3), respectively. As shown in

  The content ratio of the C—H bond having a bond dissociation energy of 3.70 eV or less in the resin (A) is not particularly limited, but may be at least one per repeating unit constituting the resin (A). preferable.

  The resin (A) is not particularly limited as long as it has a C—H bond having a bond dissociation energy of 3.70 eV or less, but is preferably a conjugated diene polymer cyclized product.

In the present invention, the conjugated diene polymer cyclized product suitably used as the resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less is obtained by cyclizing a conjugated diene polymer in the presence of an acid catalyst. It is obtained by chemical reaction.
As the conjugated diene polymer, homopolymers and copolymers of conjugated diene monomers and copolymers of conjugated diene monomers and monomers copolymerizable therewith can be used.

The conjugated diene monomer is not particularly limited, and specific examples thereof include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1, Examples include 3-pentadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, and 3-butyl-1,3-octadiene.
These monomers may be used alone or in combination of two or more.

Examples of other monomers copolymerizable with the conjugated diene monomer include styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, and pt. Aroma such as butyl styrene, α-methyl styrene, α-methyl-p-methyl styrene, o-chloro styrene, m-chloro styrene, p-chloro styrene, p-bromo styrene, 2,4-dibromo styrene, vinyl naphthalene Group vinyl monomers; chain olefin monomers such as ethylene, propylene and 1-butene; cyclic olefin monomers such as cyclopentene and 2-norbornene; 1,5-hexadiene, 1,6-heptadiene, 1,7 -Non-conjugated diene monomers such as octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene; (meth) acryl (Meth) acrylic acid esters such as methyl acid and ethyl (meth) acrylate; other (meth) acrylic acid derivatives such as (meth) acrylonitrile and (meth) acrylamide;
These monomers may be used alone or in combination of two or more.

  Specific examples of the conjugated diene polymer include homopolymers or copolymers of conjugated dienes such as natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), butadiene-isoprene copolymer rubber (BIR); Styrene-butadiene rubber (SBR), isoprene-isobutylene copolymer rubber (IIR), ethylene-propylene-diene copolymer rubber (EPDM), aromatic vinyl-conjugated diene block copolymer such as styrene-isoprene block copolymer And a copolymer of a conjugated diene such as a polymer and a monomer copolymerizable therewith. Among these, polyisoprene rubber, polybutadiene rubber and styrene-isoprene block copolymer are preferable, and polyisoprene rubber and styrene-isoprene block copolymer are more preferable.

  The content of the conjugated diene monomer unit in the copolymer of the conjugated diene and the monomer copolymerizable therewith is appropriately selected within a range not impairing the effects of the present invention, but usually 10 mol% or more , Preferably it is 50 mol% or more, More preferably, it is 70 mol% or more. Especially, what consists only of a conjugated diene monomer unit is preferable. If the content of the conjugated diene monomer unit is too small, it may be difficult to obtain a suitable range of unsaturated bond reduction rate.

  When the conjugated diene polymer cyclized product is a cyclized product of an aromatic vinyl-conjugated diene block copolymer, the aromatic vinyl monomer unit content in the cyclized product is not particularly limited, but is usually 1 to 90% by weight. , Preferably 5 to 50% by weight, more preferably 10 to 30% by weight. If the content is too small, the initial mechanical strength of the oxygen-absorbing resin composition tends to decrease, and the mechanical strength after oxygen absorption tends to decrease. On the other hand, if the aromatic vinyl monomer unit content is too large, the proportion of the conjugated diene polymer cyclized block is relatively decreased, and the oxygen absorption amount tends to decrease or the oxygen absorption rate tends to decrease.

  The polymerization method of the conjugated diene polymer may be in accordance with a conventional method, for example, solution polymerization or emulsification using an appropriate catalyst such as a Ziegler polymerization catalyst, an alkyl lithium polymerization catalyst or a radical polymerization catalyst containing titanium as a catalyst component. Performed by polymerization.

The conjugated diene polymer cyclized product used in the present invention is obtained by subjecting the conjugated diene polymer to a cyclization reaction in the presence of an acid catalyst.
Known acid catalysts can be used for the cyclization reaction. Specific examples thereof include sulfuric acid; fluoromethanesulfonic acid, difluoromethanesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, alkylbenzenesulfonic acid having an alkyl group having 2 to 18 carbon atoms, anhydrides and alkyl esters thereof, and the like. Organic sulfonic acid compounds: boron trifluoride, boron trichloride, tin tetrachloride, titanium tetrachloride, aluminum chloride, diethylaluminum monochloride, ethylammonium chloride, aluminum bromide, antimony pentachloride, tungsten hexachloride, iron chloride, etc. A Lewis acid; and the like. These acid catalysts may be used alone or in combination of two or more. Among these, organic sulfonic acid compounds are preferable, and p-toluenesulfonic acid and xylenesulfonic acid are more preferable.
The usage-amount of an acid catalyst is 0.05-10 weight part normally per 100 weight part of conjugated diene polymers, Preferably it is 0.1-5 weight part, More preferably, it is 0.3-2 weight part.

The cyclization reaction is usually performed by dissolving a conjugated diene polymer in a hydrocarbon solvent.
The hydrocarbon solvent is not particularly limited as long as it does not inhibit the cyclization reaction. For example, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene; n-pentane, n-hexane, n-heptane, n -Aliphatic hydrocarbons such as octane; Alicyclic hydrocarbons such as cyclopentane and cyclohexane; and the like. The boiling point of these hydrocarbon solvents is preferably 70 ° C. or higher.
The solvent used for the polymerization reaction of the conjugated diene polymer and the solvent used for the cyclization reaction may be of the same type. In this case, an acid catalyst for cyclization reaction can be added to the polymerization reaction solution after completion of the polymerization reaction, and the cyclization reaction can be carried out following the polymerization reaction.
The amount of the hydrocarbon solvent used is such that the solid content concentration of the conjugated diene polymer is usually 5 to 60% by weight, preferably 20 to 40% by weight.

The cyclization reaction can be carried out under any pressure of pressure, reduced pressure and atmospheric pressure, but it is desirable to carry out under atmospheric pressure from the viewpoint of easy operation. When the cyclization reaction is performed in a dry air flow, particularly in an atmosphere of dry nitrogen or dry argon, side reactions caused by moisture can be suppressed.
The reaction temperature and reaction time in the cyclization reaction are not particularly limited. The reaction temperature is usually 50 to 150 ° C., preferably 70 to 110 ° C., and the reaction time is usually 0.5 to 10 hours, preferably 2 to 5 hours.
After carrying out the cyclization reaction, the acid catalyst is deactivated and the acid catalyst residue is removed by a conventional method, and then the hydrocarbon solvent is removed to obtain a solid conjugated diene polymer cyclized product. .

In the present invention, the conjugated diene polymer cyclized product preferably has an unsaturated bond reduction rate of 60% or less, more preferably 55 to 40%.
By using the conjugated diene polymer cyclized product having an unsaturated bond reduction rate of 60% or less, the oxygen absorption amount and oxygen absorption rate of the oxygen-absorbing resin composition of the present invention are excellent.

Here, the unsaturated bond reduction rate is an index representing the degree to which the unsaturated bond is reduced by the cyclization reaction in the conjugated diene monomer unit portion in the conjugated diene polymer, and is a numerical value obtained as follows. It is. That is, by proton NMR analysis, in the conjugated diene monomer unit portion in the conjugated diene polymer, the ratio of the peak area of the proton directly bonded to the double bond to the peak area of all protons is measured before and after the cyclization reaction, respectively. Calculate the reduction rate.
Now, in the conjugated diene monomer unit part in the conjugated diene polymer, the total proton peak area before the cyclization reaction is SBT, the peak area of the proton directly bonded to the double bond is SBU, and the total proton after the cyclization reaction When the peak area is SAT and the peak area of proton directly bonded to a double bond is SAU,
The peak area ratio (SB) of the proton directly bonded to the double bond before the cyclization reaction is
SB = SBU / SBT
The peak area ratio (SA) of the proton directly bonded to the double bond after the cyclization reaction is
SA = SAU / SAT
Therefore, the unsaturated bond reduction rate is obtained by the following equation.
Unsaturated bond reduction rate (%) = 100 × (SB−SA) / SB

The unsaturated bond reduction rate of the conjugated diene polymer cyclized product can be adjusted by appropriately selecting the amount of acid catalyst, reaction temperature, reaction time, and the like in the cyclization reaction.
In order to obtain a conjugated diene polymer cyclized product having a desired unsaturated bond reduction rate, a calibration curve is prepared in advance for the amount of acid catalyst, reaction temperature, reaction time, etc. in the cyclization reaction. A method such as performing a cyclization reaction may be employed.

The weight average molecular weight of the conjugated diene polymer cyclized product (A) used in the present invention is preferably in the range of 10,000 to 1,000,000 in terms of standard polystyrene measured by gel permeation chromatography. 20,000 to 700,000 is more preferable, and 30,000 to 500,000 is still more preferable.
When the conjugated diene polymer cyclized product is a cyclized product of an aromatic vinyl-conjugated diene block copolymer, the weight average molecular weight of the aromatic vinyl polymer block is preferably 1,000 to 500,000, more preferably Is 3,000 to 300,000, more preferably 5,000 to 100,000, and particularly preferably 8,000 to 50,000. If the weight average molecular weight is too low, the initial mechanical strength of the oxygen-absorbing resin composition tends to decrease, and the mechanical strength after oxygen absorption tends to decrease. On the contrary, when the weight average molecular weight is too high, the ratio of the conjugated diene polymer cyclized product block tends to be relatively lowered, and the oxygen absorption amount tends to be lowered.
The weight average molecular weight of the conjugated diene polymer cyclized product can be adjusted by appropriately selecting the weight average molecular weight of the conjugated diene polymer subjected to cyclization.
If the weight average molecular weight of the conjugated diene polymer cyclized product is too low, it is difficult to form into a film and the mechanical strength may be lowered. When the weight average molecular weight of the conjugated diene polymer cyclized product is too high, the solution viscosity at the time of the cyclization reaction is increased, it becomes difficult to handle, and the workability in extrusion molding may be reduced.

  The gel (toluene insoluble content) of the conjugated diene polymer cyclized product is usually 10% by weight or less, preferably 5% by weight or less, but it is particularly preferable that the conjugated diene polymer cyclized product has substantially no gel. When the amount of gel is large, there is a risk of impairing the smoothness of the film.

  In the present invention, an antioxidant may be added to the conjugated diene polymer cyclized product in order to ensure thermal stability during processing of the conjugated diene polymer cyclized product. The amount of the antioxidant is not particularly limited, but is usually in the range of 10 to 5,000 ppm, preferably 30 to 3,000 ppm, more preferably 50 to 2,000 ppm based on the weight of the conjugated diene polymer cyclized product. It is.

  Further, the amount of the antioxidant in the oxygen-absorbing resin composition of the present invention is usually in the range of 10 to 3,000 ppm, preferably 30 to 2,000 ppm, and more preferably 50 to 1,000 ppm. However, if the amount of the antioxidant added is too large, the oxygen absorbability is lowered. Therefore, it is important to appropriately adjust the amount added while considering the stability during processing of the oxygen-absorbing resin composition.

  The antioxidant is not particularly limited as long as it is usually used in the field of resin materials or rubber materials. Representative examples of such antioxidants include hindered phenol-based, phosphorus-based and lactone-based antioxidants. These antioxidants can also be used in combination of two or more. In particular, the combined use of a phenolic antioxidant and a phosphorus antioxidant is preferable. An amine light stabilizer (HALS) may be added.

  Specific examples of hindered phenol antioxidants include 2,6-di-t-butyl-p-cresol, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl). Propionate], thiodiethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionamide], diethyl [[3,5-bis (1,1-dimethylethyl) ) -4-Hydroxyphenyl] methyl] phosphonate, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-t-butyl-a, a ′, a ″-(mesitylene-2 4,6-triyl) tri-p-cresol, hexamethylenebis [3- (3,5-di-t-butyl) -4-hydroxyphenyl] propionate, tetrakis [methylene-3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate] methane, n-octadecyl-3- (4′-hydroxy-3,5′-di-t-butylphenyl) propionate, 1,3,5-tris (3,5 -Di-t-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,4-bis- (n-octylthio) -6 (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 2-t- The 6- (3'-t-butyl-2'-hydroxy-5'-methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-t-phenyl) Ethyl] -4,6-di-t-pentylphenyl acrylate and the like.

Phosphorus antioxidants include 2,2′-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, bisphosphite [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diyl Bisphosphonite, bis (2,4-di-t-butylphenyl) pentaerythritol phosphite, etc. can be shown.
Examples of lactone antioxidants include reaction products of 5,7-di-t-butyl-3- (3,4-dimethylphenyl) -3H-benzofuran-2-one and o-xylene. be able to.

  In addition to the cyclized conjugated diene polymer, various compounds that are usually added may be blended as necessary. Examples of such compounds include fillers such as calcium carbonate, alumina and titanium oxide; tackifiers (hydrogenated petroleum resins, hydrogenated terpene resins, castor oil derivatives, sorbitan higher fatty acid esters, low molecular weight polybutenes); plasticizers ( Phthalates, glycol esters); surfactants; leveling agents; UV absorbers; light stabilizers; dehydrating agents; pot life extenders (acetylacetone, methanol, methyl orthoacetate, etc.); repellent improvers; it can.

In the present invention, if necessary, a poly α-olefin resin can be used in combination with the conjugated diene polymer cyclized product. Thereby, the mechanical strength before and after oxygen absorption can be improved without affecting the oxygen absorption rate and oxygen absorption amount of the oxygen-absorbing resin composition.
The poly α-olefin resin is an α-olefin homopolymer, a copolymer of two or more α-olefins, or a copolymer of α-olefin and a monomer other than α-olefin. In addition, these (co) polymers may be modified.

Specific examples of the poly α-olefin resin include homopolymers or copolymers of α-olefin such as ethylene and propylene, such as linear low density polyethylene (LLDPE), low density polyethylene (LDPE), and medium density polyethylene. (MDPE), high density polyethylene (HDPE), polyethylene such as metallocene polyethylene, polypropylene, metallocene polypropylene, polymethylpentene, polybutene and other α-olefin homopolymers; ethylene and other α-olefin copolymers, such as , Ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-propylene-polybutene-1 copolymer, etc .; copolymer of α-olefin and carboxylic unsaturated alcohol mainly composed of α-olefin Coalescence and saponified products thereof, for example Tylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, etc .; α-olefin and α, β-unsaturated carboxylic acid ester or α, β-unsaturated carboxylic acid, etc. mainly composed of α-olefin Copolymers such as ethylene-α, β-unsaturated carboxylic acid ester copolymers (ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, etc.), ethylene-α, β-unsaturated carboxylic acid Acid copolymers (ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, etc.), etc .; α-olefin (co) polymers such as polyethylene and polypropylene are treated with acrylic acid, methacrylic acid, maleic acid, maleic anhydride , Acid-modified poly-α-olefin resins modified with unsaturated carboxylic acids such as fumaric acid and itaconic acid; copolymers of ethylene and methacrylic acid with N Ionomer resin allowed to act ions and Zn ions; mixtures thereof; and the like.
A poly alpha olefin resin may be used individually by 1 type, or may use 2 or more types together. The amount of the poly α-olefin resin used is preferably 0 to 90% by weight, more preferably 10 to 80% by weight, more preferably 15 to 70% by weight based on 100 parts by weight of the total of the conjugated diene polymer cyclized product and the polyolefin resin. % Is more preferable, and 20 to 50% by weight is particularly preferable. Within the above range, the oxygen absorption rate of the oxygen-absorbing resin composition and the balance between the oxygen absorption amount and the mechanical strength are better maintained, and the higher the ratio of the conjugated diene polymer cyclized product, the higher the oxygen absorption rate and oxygen absorption. The amount is good.

  The resin (B) having a C—H bond having a bond dissociation energy of more than 3.70 eV and not more than 4.20 eV, which is another essential component of the oxygen-absorbing resin composition of the present invention, is not particularly limited. The bond dissociation energy of the resin (B) is preferably more than 3.70 eV and not more than 4.17 eV.

Specific examples of the resin (B) having a C—H bond having a bond dissociation energy exceeding 3.70 eV and not more than 4.20 eV include cyclic olefin resins. The cyclic olefin resin may be a cyclic olefin ring-opening polymer or an addition polymer. Moreover, in addition to the homopolymer and copolymer of cyclic olefin, the copolymer of cyclic olefin and the other olefin copolymerizable with this may be sufficient. Further, the resin (B) may be obtained by (co) polymerization of a cyclic olefin, followed by polymer modification by maleic acid addition, cyclopentadiene addition, or the like, or hydrogenation.
In the present invention, the resin (B) is preferably a cyclic olefin resin, but it is a resin obtained from a monomer other than the cyclic olefin, and the cyclic olefin resin can be obtained by treatment after polymerization such as hydrogenation. It may have come to have an equivalent structure.

  Although the weight average molecular weight of the cyclic olefin resin used for this invention is not specifically limited, It is a standard polystyrene conversion value by the gel permeation chromatography (GPC) by a toluene or a cyclohexane solvent, Usually, 1,000-1,000,000. 000, preferably 10,000 to 500,000, more preferably 20,000 to 100,000. When the weight average molecular weight is excessively small, the physical strength of the oxygen-absorbing resin composition obtained using this resin is inferior, and conversely, when it is excessively large, molding may be difficult.

Examples of cyclic olefin resins include ring-opening (co) polymers of cyclic olefins, addition (co) polymers of cyclic olefins, cyclic olefins and α-olefins as described in JP-A-7-231928 And addition copolymers thereof, and hydrogenated products thereof.
The cyclic olefin may be a monocyclic olefin or a polycyclic olefin, and may have a condensed ring portion with an aromatic ring or the like, but as a typical example, bicyclo [2.2.1] hept-2-ene And tetracyclo [6.2.1.1 ^3,6 . Norbornene compound monomers such as 0 ^2,7 ] dodec-4-enes.

  Specific examples of the norbornene compound monomer include norbornene; 5-methyl-2-norbornene, 5,5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, and 5-ethylidene. Norbornene compounds such as norbornene alkyl or alkylidene substituents such as 2-norbornene; polar group (halogen atom, cyano group, pyridyl group, methoxy group, etc.) substituent of norbornene compounds; dicyclopentadiene, 2,3-dihydrodi Dicyclopentadiene such as cyclopentadiene; adduct of cyclopentadiene and tetrahydroindene; 4,9: 5,8-dimethano-3a, 4,4a, 5,8,8a, 9,9a-octahydro-1H- Benzoindene, 4,11: 5, 10: 6,9-trimethano-3a, 4,4 , 5,5a, 6,9,9a, 10,10a, 11,11a-cyclopentadiene 3-tetramer such as dodecahydro-1H-cyclopentanthracene; 6-methyl-1,4: 5,8-dimethano -1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a -Dimethanooctahydronaphthalenes such as octahydronaphthalene, 6-ethylidene-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene; 6-chloro -1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-cyano-1,4: 5,8-dimethano-1,4,4a , 5,6,7,8,8a-octahydronaphthalene, -Pyridyl-1,4: 5,8-dimethano-1,4,4a, 5,6,7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1,4: 5,8-dimethano-1, Polar group-substituted dimethanooctahydronaphthalenes such as 4,4a, 5,6,7,8,8a-octahydronaphthalene; and the like.

Examples of monomers copolymerizable with the norbornene compound monomer include α-olefins such as ethylene and propylene; monocyclic olefins such as cyclopentene; styrenes such as styrene.
Polymerization of these cyclic olefin resins and their hydrogenation can be carried out by conventional methods.

  In the present invention, among these cyclic olefin resins, ethylene-cyclic olefin copolymers such as an ethylene-norbornene copolymer and an ethylene-tetracyclododecane copolymer are suitable.

  The method for producing the oxygen-absorbing resin composition of the present invention includes a resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less, and a C having a bond dissociation energy of more than 3.70 eV and 4.20 eV or less. As long as the resin (B) having —H bond can be mixed uniformly, the surface is not particularly limited, and a generally flat surface is obtained after a known method, for example, (A) and (B) are dissolved in a solvent. A solution casting method in which a solution is applied and dried; a method in which (A) and (B) are melt-kneaded with a kneader such as an extruder, a kneader, and / or a Banbury mixer;

  In the oxygen-absorbing resin composition of the present invention, the resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less and a C—H bond having a bond dissociation energy of more than 3.70 eV and 4.20 eV or less It is preferable that content ratio with resin (B) which has this is 3 / 97-50 / 50 by weight ratio. Content ratio of resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less and resin (B) having a C—H bond having a bond dissociation energy of more than 3.70 eV and not more than 4.20 eV Is within the above range, it is possible to obtain an oxygen-absorbing resin composition that is particularly excellent in oxygen absorption rate and oxygen absorption at room temperature, has a particularly low odor during oxygen absorption, and has excellent mechanical strength. it can.

The reason why the oxygen-absorbing resin composition of the present invention is particularly excellent in oxygen absorption rate and oxygen absorption at room temperature and does not generate odor during oxygen absorption is not limited to the present invention, but Can be considered.
The resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less, which is one component of the oxygen-absorbing resin composition of the present invention, easily generates> C · radicals by heat or light. At this time, when the oxygen-absorbing resin composition encounters oxygen, the> C · radical reacts immediately with oxygen to easily generate> COO · radical. If a radical acceptor having a low bond dissociation energy is present in the oxygen-absorbing resin composition, hydrogen is extracted from the radical acceptor to produce> COOH, which decomposes to produce> CO.radical or HO.radical. Then, the entire system proceeds to auto-oxidation, and as a result, oxygen is consumed by radicals, and as a result, oxygen absorption proceeds. In this case, if the radical acceptor has an alicyclic structure, even if hydrogen is extracted, the entire molecule will not be decomposed, resulting in a low odor generation amount. That is, the oxygen-absorbing resin composition of the present invention has a bond dissociation energy in a matrix of a resin (B) having a C—H bond having a bond dissociation energy exceeding 3.70 eV and not more than 4.20 eV. Presents a resin (A) having a C—H bond of 3.70 eV or less, the resin (A) starts an oxygen absorption reaction, and this oxygen absorption reaction is absorbed by the resin (B) constituting the matrix. Causes reaction and oxygen absorption proceeds. When this matrix resin (B) has an alicyclic structure, it is hardly decomposed even by oxygen absorption (bond dissociation), and as a result, the odor due to the decomposition product is also reduced.
In addition, when the ratio of the matrix resin (B) is high as described above, since the decomposition due to oxygen absorption is small, an oxygen-absorbing resin composition having excellent mechanical strength can be obtained both before and after oxygen absorption. .

  Unlike the conventional oxygen absorbent, the oxygen-absorbing resin composition of the present invention does not need to contain a metal compound that serves as a catalyst for the oxygen absorption reaction. The oxygen-absorbing resin composition of the present invention does not require such a catalyst, has a large oxygen absorption amount per film weight, and has a high oxygen absorption rate per unit time / film unit area. Can demonstrate its sexuality.

The oxygen-absorbing film of the present invention comprises the oxygen-absorbing resin composition of the present invention.
In the present invention, unless otherwise specified, a film is a concept that includes both a film and a sheet that are strictly distinguished by thickness.
The method for forming the oxygen-absorbing resin composition of the present invention into a film is not particularly limited, and a conventionally known method can be employed. For example, after dissolving the oxygen-absorbing resin composition of the present invention in a solvent, a film can be obtained by a solution casting method in which a solution is applied and dried on a substantially flat surface. Further, for example, after melt-kneading a resin composition or the like with an extruder, it is extruded into a predetermined shape through a T-die, a circular die (ring die) or the like to obtain a T-die method film, a blown film, or the like. . As the extruder, a kneader such as a single screw extruder, a twin screw extruder, or a Banbury mixer can be used. A T-die film can be made into a biaxially stretched film by biaxially stretching it.

The oxygen-absorbing multilayer body of the present invention has an oxygen-absorbing layer comprising at least the oxygen-absorbing resin composition of the present invention.
In the oxygen-absorbing multilayer body of the present invention, the oxygen-absorbing layer may contain known oxygen-absorbing components other than the oxygen-absorbing resin composition of the present invention as long as the effects of the present invention are not impaired. The amount of the oxygen-absorbing component other than the oxygen-absorbing resin composition of the present invention is the total amount of the oxygen-absorbing component (the oxygen-absorbing components other than the oxygen-absorbing resin composition of the present invention and the oxygen-absorbing resin composition of the present invention). Less than 50% by weight, preferably less than 40% by weight, more preferably less than 30% by weight relative to the total component).
The oxygen-absorbing layer of the oxygen-absorbing multilayer body of the present invention absorbs oxygen from the outside that permeates the gas barrier material layer according to the configuration of the multilayer body. A function of absorbing oxygen inside the packaging material via the sealing material layer when a packaging material made of an oxygen-absorbing multilayer body having a layer-gas barrier material layer is used, for example, when a bag-like packaging container is constructed. It becomes the layer which has.

The oxygen-absorbing multilayer body of the present invention preferably has at least a gas barrier material layer in addition to the oxygen-absorbing layer.
The structure of the oxygen-absorbing multilayer body of the present invention is not particularly limited, and may be a film, a sheet, or other structure.

Moreover, the oxygen-absorbing multilayer body of the present invention may further have a sealing material layer, a supporting base material layer, a deodorant layer, a surface resin layer, or a protective layer.
In the oxygen-absorbing multilayer body of the present invention, the order of lamination of the respective layers constituting the oxygen-absorbing multilayer body is not particularly limited, but is usually a sealing material layer / oxygen-absorbing layer / gas barrier material layer / deodorant layer / surface resin layer / It is a protective layer. What is necessary is just to provide a required layer among these each layer as needed.

A gas barrier material layer is a layer provided in order to prevent permeation | transmission of the gas from the outside. The gas barrier material layer becomes an outer layer when, for example, a bag-shaped packaging material is formed from the oxygen-absorbing multilayer body. The oxygen permeability of the gas barrier material layer is preferably as low as possible as the workability and cost allow, and should be 100 cc / m ² · atm · day (25 ° C., 65% RH) or less regardless of the film thickness. Necessary, more preferably 50 cc / m ² · atm · day (25 ° C., 65% RH) or less.

The material for constituting the gas barrier material layer is not particularly limited as long as it has a low gas permeability such as oxygen and water vapor, and a metal, an inorganic material, a resin, or the like is used.
As the metal, aluminum having low gas permeability is generally used. The metal may be laminated as a foil on a resin film or the like, or a thin film may be formed on the resin film or the like by vapor deposition.
As the inorganic material, metal oxides such as silica and alumina are used, and these metal oxides are used alone or in combination and deposited on a resin film or the like.
Although the resin does not reach the metal and inorganic materials in terms of gas barrier properties, there are many choices in mechanical properties, thermal properties, chemical resistance, optical properties, and manufacturing methods. Because of these advantages, the gas barrier material layer Is preferably used. The resin used in the gas barrier material layer of the present invention is not particularly limited, and any resin having good gas barrier properties can be used. However, if a resin not containing chlorine is used, it is harmful when incinerated. Since it does not generate | occur | produce gas, it is preferable.
Among these, the transparent vapor deposition film which vapor-deposited the inorganic oxide on the resin film is used preferably.

  Specific examples of the resin used as the gas barrier material layer include polyvinyl alcohol resins such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; nylon 6, nylon 66, nylon 610, Polyamide resin such as nylon 11, nylon 12, MXD nylon (polymetaxylylene adipamide) and copolymers thereof; polyaramid resin; polycarbonate resin; polystyrene resin; polyacetal resin; fluororesin; polyether type, adipate ester type , Caprolactone ester-based, polycarbonate-based thermoplastic polyurethane; polyvinylidene chloride, polyvinyl chloride and other halogenated resins; polyacrylonitrile; α-olefin Copolymer of vinyl acetate, acrylic acid ester, methacrylic acid ester, etc., for example, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid Copolymers, ethylene-methacrylic acid copolymers; α-olefin (co) polymers such as polyethylene and polypropylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid And an acid-modified poly α-olefin resin modified with 1); an ionomer resin in which Na ion or Zn ion is allowed to act on a copolymer of ethylene and methacrylic acid; a mixture thereof; It is also possible to deposit inorganic oxides such as aluminum oxide and silicon oxide on these gas barrier material layers.

  These resins can be used for multi-layered products considering desired properties such as gas barrier properties, mechanical properties such as strength, toughness and rigidity, heat resistance, printability, transparency, and adhesiveness. It can be selected appropriately. These resins may be used alone or in combination of two or more.

The resin used as the gas barrier material layer includes a heat stabilizer, an ultraviolet absorber, an antioxidant, a colorant, a pigment, a neutralizer, a plasticizer such as a phthalate ester and a glycol ester, a filler, a surfactant, and a leveling. Agents; Light stabilizers; Dehydrating agents such as alkaline earth metal oxides; Deodorizing agents such as activated carbon and zeolite; Tackifiers (castor oil derivatives, sorbitan higher fatty acid esters, low molecular weight polybutenes); Methanol, methyl orthoacetate, etc.); repellent improvers; other resins (poly α-olefins, etc.);
Moreover, an antiblocking agent, an antifogging agent, a weather resistance stabilizer, a lubricant, an antistatic agent, a reinforcing agent, a flame retardant, a coupling agent, a foaming agent, a release agent, and the like can be added as necessary.
In addition, the gas barrier material layer can be subjected to surface printing or back printing by a normal printing method with a desired printing pattern such as characters, figures, symbols, patterns, and patterns.

A protective layer can be formed on the outside of the gas barrier material layer for the purpose of imparting heat resistance.
Examples of the resin used for the protective layer include ethylene polymers such as high-density polyethylene; propylene polymers such as propylene homopolymer, propylene-ethylene random copolymer, and propylene-ethylene block copolymer; nylon 6, nylon 66, and the like. Polyamide; Polyester such as polyethylene terephthalate; Of these, polyamide and polyester are preferred.
In addition, when a polyester film, a polyamide film, an inorganic oxide vapor deposition film, a vinylidene chloride coating film, etc. are used as a gas barrier material layer, these gas barrier material layers simultaneously function as a protective layer.

  In the oxygen-absorbing multilayer body of the present invention, the sealing material layer which may be provided as desired is a space which is sealed from the outside of the packaging container by melting and adhering to each other (heat sealing) by heat. And a layer that allows oxygen to permeate and absorb into the oxygen-absorbing layer while preventing direct contact between the oxygen-absorbing layer and the packaged item inside the packaging container.

  Specific examples of the heat-sealable resin used for forming the sealing material layer include: α-olefin homopolymer; copolymer of ethylene and α-olefin; α-olefin and acetic acid mainly composed of α-olefin Copolymer with vinyl, acrylic acid ester, methacrylic acid ester, etc .; acid-modified poly α-olefin resin obtained by modifying α-olefin (co) polymer with unsaturated carboxylic acid; ionomer resin; It is done.

The oxygen permeability at 25 ° C. of the sealing material layer is preferably 200 cc / m ² · atm · day (20 μm) or more, regardless of the number of layers, the film thickness, and the constituent materials, and 400 cc / m ² · atm · It is particularly preferable that the length is not less than day (20 μm).
The permeability is represented by the volume of gas passing through the test piece of unit area per unit time in unit partial pressure difference, and is measured by the method specified in JIS K7126 “Method for testing gas permeability of plastic film and sheet”. be able to.

The oxygen-absorbing multilayer body of the present invention may have a deodorant layer containing a deodorizing component.
A well-known thing can be used as a deodorizing component. The deodorizing component may be an adsorbent that captures the odor component by an adsorption action, or may be a deodorization agent that has a deodorizing action that changes the odor component to an odorless component by a chemical reaction or the like. Further, it may have both an adsorption action and a deodorizing action.

  Adsorbents are organic adsorbents such as soybean powder, polyester resin, acrylic resin, natural zeolite, synthetic zeolite, silica gel, activated carbon, impregnated activated carbon, activated clay, activated aluminum oxide, clay, diatomaceous earth, kaolin, talc, bentonite, oxidized Inorganic adsorbents such as clay minerals such as magnesium, iron oxide, aluminum hydroxide, magnesium hydroxide, iron hydroxide, magnesium silicate, aluminum silicate, synthetic hydrotalcite, silicon dioxide, sepiolite, mica, etc. From the viewpoint, an inorganic adsorbent is preferable.

  In the present invention, a basic compound is suitable as the deodorizer. This is because, in the present invention, the oxygen absorption action of the conjugated diene polymer cyclized product, which is an active component of the oxygen-absorbing gas barrier resin layer, is first generated by extracting active hydrogen from the conjugated diene polymer cyclized product. Then, this radical captures oxygen molecules to become peroxy radicals, and this peroxy radical advances through a mechanism of repeating a cycle of drawing out a hydrogen atom, and as a result, it is thought that acidic components such as aldehydes and acids are generated. It is.

  Basic compounds include alkali metal or alkaline earth metal hydroxides; other hydroxides such as iron hydroxide; carbonates and bicarbonates of alkali metals and alkaline earth metals; ammonia; amino groups or iminos An organic basic compound such as a compound containing a group; a compound containing an amide group or an imide group; a urea bond-containing compound;

In the oxygen-absorbing multilayer body of the present invention, a surface resin layer may be provided outside the gas barrier material layer.
The resin used for forming the surface resin layer is preferably a heat-sealable resin that can be melted by heating and fused to each other and can be extruded.
In addition, when the oxygen-absorbing multilayer tube is used as various containers, it is preferable that printing by gravure printing, flexographic printing, or the like is possible for displaying contents.

  The film thickness of the surface resin layer is preferably in the range of 5 to 150 μm, more preferably in the range of 10 to 100 μm, regardless of the constituent materials. When the film thickness of the surface resin layer is within the above range, sufficient oxygen absorption ability is exhibited.

The oxygen-absorbing multilayer body of the present invention may have a support base material layer as necessary. The material constituting the support base layer is a poly α-olefin resin; a polyester resin such as polyethylene terephthalate (PET); a polyamide resin such as polyamide 6 or polyamide 6-polyamide 66 copolymer; a natural fiber; a synthetic fiber; Paper obtained by papermaking is used.
The supporting substrate layer may be provided between the oxygen absorbing layer and the gas barrier material layer, or may be provided in the order of oxygen absorbing layer / gas barrier material layer / supporting substrate layer.

  Moreover, you may form an adhesive bond layer in order to adhere | attach each layer. For the adhesive layer, a resin film or sheet that can be melted by heat and fused to each other can be used. Specific examples of such a resin include an α-olefin homopolymer or copolymer; an acid-modified poly α-olefin resin; an ionomer resin; a mixture thereof;

  The protective layer, sealing material layer, deodorant layer, surface resin layer, support base material layer, adhesive layer and the like provided as necessary to the oxygen-absorbing multilayer body of the present invention are the same as the gas barrier material layer. Various compounding agents may be added.

The method for producing the oxygen-absorbing multilayer body of the present invention is not particularly limited, and a single layer film of each layer constituting the multilayer body may be obtained and laminated, or the multilayer body may be directly molded.
A single layer film can be obtained by the method similar to the method of making the oxygen absorptive resin composition of this invention into a film.
A multilayer body can be produced from the monolayer film obtained as described above by an extrusion coating method, sandwich lamination, or dry lamination.

For the production of the multilayer body, a known coextrusion molding method can be used. For example, the extrusion molding can be performed in the same manner as described above except that a multilayer multiple die is used by using the number of extruders corresponding to the type of resin. That's fine.
Examples of the coextrusion molding method include a coextrusion lamination method, a coextrusion film molding method, and a coextrusion inflation molding method.
For example, the resin constituting the gas barrier material layer, the oxygen absorbing layer and the sealing material layer are melt-heated by several extruders by a water-cooled or air-cooled inflation method, respectively, and multilayered annular From a die, for example, it is extruded at an extrusion temperature of 190 to 210 ° C., and is immediately quenched and solidified with a liquid refrigerant such as cooling water to form a tube-shaped original fabric.

In the production of the multilayer body, the temperature of the resin for each layer constituting the multilayer body is preferably set to 160 to 250 ° C. If it is less than 160 ° C., uneven thickness or cutting of the multilayer body may occur, and if it exceeds 250 ° C., the multilayer body may be cut. More preferably, it is 170-230 degreeC.
The winding speed during the production of the multilayer body is usually 2 to 200 m / min, preferably 50 to 100 m / min. If the winding speed is 2 m / min or less, the production efficiency may be deteriorated, and if it exceeds 200 m / min, the multilayer body cannot be sufficiently cooled, and may be fused at the time of winding.

When the multilayer body is made of a stretchable material and its properties are improved by stretching, such as polyamide resin, polyester resin, polypropylene, etc., the multilayer film obtained by coextrusion is further uniaxially or biaxially stretched. be able to. If necessary, it can be further heat set.
Although a draw ratio is not specifically limited, Usually, it is 1 to 5 times in the longitudinal direction (MD) and the transverse direction (TD), respectively, preferably 2.5 to 4.5 times in the longitudinal and transverse directions, respectively. .
Stretching can be performed by a known method such as a tenter stretching method, an inflation stretching method, or a roll stretching method. The order of stretching may be either longitudinal or lateral, but is preferably simultaneous, and a tubular simultaneous biaxial stretching method may be employed.

The oxygen-absorbing multilayer body of the present invention can be used by forming into various shapes of packaging containers.
Packaging containers can be used in various forms according to their purpose, application, etc., for example, liquid packaging containers having shapes such as a gobel top, brick type, cube, regular tetrahedron, other trays, cup-shaped containers, pouch-shaped It can be used as a container.

  The molding method for obtaining these packaging containers is not particularly limited, and the oxygen-absorbing multilayer body is reheated at a temperature equal to or lower than the melting point of the resin constituting the container, and is drawn, vacuum-formed, compressed-air molded, or press-molded. A stretched molded product can be obtained by uniaxially or biaxially stretching by a thermoforming method such as a roll stretching method, a pantograph stretching method, or an inflation stretching method.

  The packaging container obtained from the oxygen-absorbing multilayer body of the present invention includes, for example, liquid drinks such as milk, juice, sake, whiskey, shochu, coffee, tea, jelly drink, health drink; seasoning liquid, sauce, soy sauce, dressing, Represented in liquid soup, mayonnaise, miso, grated spices, etc .; pasty food such as jam, cream, chocolate paste, yogurt, jelly; liquid processed food such as liquid soup, boiled food, pickles, stew; Liquid foods, raw noodles such as buckwheat, udon, ramen and boiled noodles; uncooked rice such as polished rice, moisture-conditioned rice, and unwashed rice; and cooked rice, cooked rice, gomoku rice, red rice, rice cake, etc. Products: Powdered soups, powder seasonings such as dashi-no-moto, etc .; high-moisture foods such as those found in convenience stores, etc .; solids and solutions such as pesticides and insecticides Chemicals; liquid and pasty pharmaceuticals; cosmetic products such as lotions, cosmetic creams, cosmetic emulsions, hair styling agents, hair dyes; detergents such as shampoos, soaps, detergents; electronic materials, recording media, etc. Articles can be stored. In the packaging container obtained from the oxygen-absorbing multilayer body of the present invention, oxygen inside the container is absorbed by the oxygen-absorbing layer, so that oxidative corrosion and the like of articles can be prevented, and good quality can be maintained for a long time. Become.

Hereinafter, the present invention will be described in more detail with reference to production examples and examples. In addition, the part and% in each example are mass references | standards unless there is particular notice.
Each characteristic was evaluated by the following method.
[Weight average molecular weight (Mw) of cyclized conjugated diene polymer]
Obtained as a molecular weight in terms of polystyrene using gel permeation chromatography.

[Reduction rate of unsaturated bond of cyclized conjugated diene polymer]
It is determined by proton NMR measurement with reference to the methods described in the following documents (i) and (ii).
(I) M.M. A. Golub and J.M. Heller, Can. J. et al. Chem. 41, 937 (1963).
(Ii) Y. Tanaka and H.M. Sato, J .; Polym. Sci: Poly. Chem. Ed. 17, 3027 (1979).
Now, in the conjugated diene monomer unit part in the conjugated diene polymer, the total proton peak area before the cyclization reaction is SBT, the peak area of the proton directly bonded to the double bond is SBU, and the total proton after the cyclization reaction When the peak area is SAT and the peak area of proton directly bonded to a double bond is SAU,
The peak area ratio (SB) of the proton directly bonded to the double bond before the cyclization reaction is
SB = SBU / SBT
The peak area ratio (SA) of the proton directly bonded to the double bond after the cyclization reaction is
SA = SAU / SAT
Therefore, the unsaturated bond reduction rate is obtained by the following equation.
Unsaturated bond reduction rate (%) = 100 × (SB−SA) / SB

[Oxygen concentration] and [Oxygen absorption rate]
The oxygen-absorbing resin composition film is cut into a size of 100 mm × 100 mm, put into an aluminum pouch of 300 mm × 400 mm (made by Sakura Bussan Co., Ltd., trade name “High Retort Aluminum ALH-9”), and the internal air Was completely removed, 100 cc of air with an oxygen concentration of 20.7% was sealed, stored at 23 ° C. for 5 days, and then an oxygen concentration meter (trade name “Food Checker HS-750”, manufactured by Ceratech, USA). Use to measure.
The oxygen absorption rate (cc / 100 cm ² · day) (20 μm) is calculated from this oxygen concentration and the oxygen concentration 20.7% before the start of the test. The larger this value, the better the oxygen absorption rate.

[Oxygen absorption]
A 0.2-0.3 g oxygen-absorbing resin composition film is precisely weighed and placed in an air circulation oven controlled at 60 ° C., and its weight change (increase) is followed over time. The amount of oxygen absorbed by 1 g of the oxygen-absorbing resin composition film is determined by assuming that all of the weight increase of the oxygen-absorbing resin composition film is due to oxygen absorption.
The larger this value, the better the oxygen absorption.

[Odor after oxygen absorption]
The oxygen-absorbing resin composition film is cut into a size of 100 mm × 100 mm, put into an aluminum pouch of 300 mm × 400 mm (made by Sakura Bussan Co., Ltd., trade name “High Retort Aluminum ALH-9”), and the internal air Was completely removed, sealed with 100 cc of air, stored at 25 ° C. for 15 days, then opened, evaluated for odor by five panel members according to the following criteria, and the evaluation score was averaged. To do. The smaller the evaluation score, the less the odor.
It does not smell at all. Evaluation score 0
Slightly smell ... Evaluation point 1
It smells a little ... Evaluation point 2
It smells ......... evaluation score 4
It smells quite strongly ... Evaluation point 5

(Reference Example 1)
Polyisoprene (cis-1,4 units 73%, trans-1,4 units 22%, 3,4) cut into 10 mm square in a pressure-resistant reactor equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube -Unit 5%, weight average molecular weight 154,000) 300 parts were charged together with 700 parts cyclohexane. After purging the inside of the reactor with nitrogen, the mixture was heated to 75 ° C. and the polyisoprene was completely dissolved in cyclohexane with stirring, and then p-toluenesulfonic acid (in toluene, so that the water content was 150 ppm or less, The product was refluxed and dehydrated. 2.19 parts were added, and the cyclization reaction was carried out so that the temperature did not exceed 80 ° C. After reacting for 7 hours, a 25% aqueous sodium carbonate solution containing 0.84 parts of sodium carbonate was added to stop the reaction. After removing water by azeotropic reflux dehydration at 80 ° C., the catalyst residue in the system was removed using a glass fiber filter having a pore size of 2 μm to obtain a conjugated diene polymer cyclized product (A-1) solution. The resulting conjugated diene polymer cyclized product (A-1) had a weight average molecular weight of 141,000 and an unsaturated bond reduction rate of 48.9%.

Example 1
In a solution of 300 parts of the conjugated diene polymer cyclized product (A-1) obtained in Reference Example 1, an amount of antioxidant corresponding to 100 ppm with respect to the conjugated diene polymer cyclized product (A-1): thiol Diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by Ciba Specialty Chemicals, trade name “Irganox 1010”) and phosphorus-based antioxidant corresponding to 200 ppm Agent, 2,2′-methylenebis (4,6-di-t-butylphenyl) octyl phosphite (manufactured by Asahi Denka Kogyo Co., Ltd., trade name “Adekastab HP-10”) and cyclic olefin resin ethylene-norbornene copolymer 700 parts of coalescence (norbornene / ethylene composition ratio = 65/35) (B-1) (manufactured by Polyplastics, trade name “TOPAS 8007X”) is added. Then, a part of cyclohexane in the solution was distilled off, vacuum drying was performed to remove toluene, and a solid conjugated diene polymer cyclized product (A-1) / ethylene-norbornene copolymer ( B-1) A blend was obtained. The blend was pulverized and round pelletized using a short-axis kneading extruder (die φ3 mm × 1 hole) to obtain pellet a of the oxygen-absorbing resin composition of the present invention.
The ethylene-norbornene copolymer (B-1) has a structure represented by the formula (3), and in the formula, the dissociation energy of the C—H bond indicated by an arrow is 4.13 eV.

(Example 2)
In place of the ethylene-norbornene copolymer (B-1), hydrogenated 3,4-polyisoprene (25% cis-1,4-structure isoprene units, 11% trans-1,4-structure isoprene units, The oxygen-absorbing resin composition of the present invention was prepared in the same manner as in Example 1 except that the hydrogenated product (B-2) having 63% of 3,4-structure isoprene units and a weight average molecular weight of 252,000 was used. Round pellet b was obtained.
The 3,4-polyisoprene hydrogenated product (B-2) has a structure represented by the formula (4). In the formula, the dissociation energy of the C—H bond indicated by the arrow is 4.17 eV. is there.

(Comparative Example 1)
Instead of the ethylene-norbornene compound copolymer (B-1), a hydrogenated product of 1,4-polyisoprene polymer (86% of cis-1,4-structure isoprene units, trans-1,4-structure isoprene units) Solid conjugated diene polymer cyclized product in the same manner as in Example 1 except that 12%, hydride of 3,4-structure isoprene unit 2%, weight average molecular weight 136,000 hydride) (C-1) was used. A hydrogenated product (C-1) blend of (A-1) / 1,4-polyisoprene polymer was obtained. The blend was pulverized and pelletized using a short shaft kneading extruder (die φ3 mm × 1 hole) to obtain pellets c of the oxygen-absorbing resin composition.
The 1,4-polyisoprene hydrogenated product (C-1) has a structure represented by the formula (2), and the dissociation energy of the C—H bond indicated by the arrow is 4.24 eV. is there.

(Comparative Example 2)
Implemented except that low density polyethylene (MFR = 4.0, manufactured by Idemitsu Petrochemical Co., Ltd., trade name “MORETECH 0438”) (C-2) was used instead of the ethylene-norbornene compound copolymer (B-1). The same operation as in Example 1 was performed to obtain a round pellet d of the oxygen-absorbing resin composition.
In addition, the low density polyethylene (C-2) has a structure shown in Formula (5), and the dissociation energy of the C—H bond indicated by an arrow in the formula is 4.30 eV. In formula (5), R represents a long-chain alkyl group.
The composition of the pellets a to d is summarized in Table 1.

(Examples 3-4, Comparative Examples 3-4)
(Evaluation of oxygen concentration, oxygen absorption rate and odor after oxygen absorption)
Using the pellets a to d prepared in Examples 1 and 2 and Comparative Examples 1 and 2, a T-die and a biaxial stretching test apparatus (both manufactured by Toyo Seiki Seisakusyo Co., Ltd.) are connected to a lab plast mill single screw extruder. Then, films fa to fd having a width of 100 mm and a thickness of 20 μm were obtained by extrusion molding. These films were cut into a size of 100 mm × 100 mm and used as test pieces to evaluate oxygen absorption, oxygen absorption rate, and odor after oxygen absorption. The results are shown in Table 2.

Table 2 shows the following.
Resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less = Conjugated diene polymer cyclized product =, and having a C—H bond having a bond dissociation energy of more than 3.70 eV and 4.20 eV or less In Examples 1-2 using resin (B) = ethylene-norbornene copolymer (= B1, Example 1) or hydrogenated 3,4-polyisoprene (= B2, Example 2) = It can be seen that the oxygen absorption amount and oxygen absorption rate at room temperature are large, and especially when an ethylene-norbornene copolymer (= B1) is used, the odor after oxygen absorption is low (Example 3).
In contrast, when resin (C) having bond dissociation energy exceeding 4.20 eV is used instead of resin (B) having bond dissociation energy exceeding 3.70 eV and having a CH bond of 4.20 eV or less It can be seen that (Comparative Examples 1 and 2) hardly or not absorbs oxygen at all and also has an odor.
This is because, in the examples of the present invention, the resin (B) having a C—H bond having a bond dissociation energy of more than 3.70 eV and not more than 4.20 eV is efficiently converted from radicals generated from the conjugated diene polymer cyclized product. In particular, in Example 1, since the resin (B) has an alicyclic structure, it is not easily decomposed even when the C—H bond is dissociated. This is thought to be because the generation of odor is small.

Claims (7)

  A resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less and a resin (B) having a C—H bond having a bond dissociation energy of more than 3.70 eV and not more than 4.20 eV An oxygen-absorbing resin composition.   The oxygen-absorbing resin composition according to claim 1, wherein the resin (A) having a C—H bond having a bond dissociation energy of 3.70 eV or less is a conjugated diene polymer cyclized product.   The oxygen-absorbing resin composition according to claim 2, wherein the conjugated diene polymer cyclized product has an unsaturated bond reduction rate of 60% or less.   The oxygen absorptivity according to any one of claims 1 to 3, wherein the resin (B) having a C-H bond having a bond dissociation energy of more than 3.70 eV and not more than 4.20 eV is a cyclic olefin resin. Resin composition.   The oxygen absorptive film which consists of an oxygen absorptive resin composition in any one of Claims 1-4.   The oxygen absorptive multilayer body which has an oxygen absorptive layer which consists of an oxygen absorptive resin composition in any one of Claims 1-4.   The oxygen-absorbing multilayer body according to claim 6, further comprising at least a gas barrier material layer.