JP5266602B2 - Oxygen-absorbing resin, oxygen-absorbing resin composition, and oxygen-absorbing container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen-absorbing resin having high oxygen-absorbing performance even in the absence of any transition metal catalyst. <P>SOLUTION: The oxygen-absorbing resin is composed of a copolyester that can be obtained by copolymerization between at least the following monomers(A) to (C). Monomer(A): a dicarboxylic acid or a derivative thereof having a carbon atom bound to both the structures (a) and (b) below and also bound to one or two hydrogen atoms, wherein the carbon atom is contained in an alicyclic structure (a) a carbon-carbon double bond group (b) any one of a functional group containing a heteroatom or a linking group derived from such a functional group, a carbon-carbon double bond group and an aromatic ring. Monomer (B): a diol. Monomer (C): at least one selected from the group consisting of a dicarboxylic acid having an aromatic ring or a derivative thereof, and a hydroxycarboxylic acid having an aromatic ring or a derivative thereof. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an oxygen-absorbing resin, an oxygen-absorbing resin composition containing the same, and an oxygen-absorbing container using the same.

In recent years, various plastic containers have been used as packaging containers because they have advantages such as light weight, transparency and easy moldability.
Since plastic containers have poor oxygen barrier properties compared to metal containers and glass containers, there is a problem in that the contents filled in the containers are chemically oxidized and deteriorated due to aerobic bacteria.
In order to prevent this, some plastic containers have a multi-layered container wall and at least one layer is provided with a resin having an excellent oxygen barrier property, for example, an ethylene-vinyl alcohol copolymer layer. . Furthermore, there is a container provided with an oxygen absorption layer in order to remove oxygen remaining inside the container and oxygen entering from the outside of the container. As an oxygen absorbent (deoxygenating agent) used for the oxygen absorbing layer, for example, there is a substance mainly containing a reducing substance such as iron powder (see, for example, Patent Document 1).

  However, the method of blending an oxygen absorbent such as iron powder into a resin and using it for the container wall of a packaging material is satisfactory in terms of high oxygen absorption performance, but because the resin is colored in a unique hue. In addition, there is a limitation in application that it cannot be used in the field of packaging that requires transparency. Further, as a resin-based oxygen-absorbing material, an oxygen-absorbing resin composition containing a resin having a carbon-carbon unsaturated bond and a transition metal catalyst (see, for example, Patent Documents 2 to 4), and a cyclic olefin (cyclohexene) structure And an oxygen-absorbing resin composition containing a transition metal catalyst (particularly, a Co salt) (see, for example, Patent Documents 5 and 6). However, the former has a problem that a low molecular weight organic component is generated as an odor component due to molecular chain scission accompanying oxygen absorption. In the latter case, since the oxygen absorption site has a ring structure, generation of a low molecular weight odor component in the former can be suppressed to some extent, but since a transition metal catalyst (Co salt) is used, it is assumed Reaction other than the oxygen absorption site is also likely to occur, and as a result, decomposition products are generated.

Japanese Examined Patent Publication No. 62-1824 JP 2001-39475 A Japanese translation of PCT publication No. 8-502306 Japanese Patent No. 3183704 Special table 2003-521552 gazette JP 2003-253131 A

  Accordingly, an object of the present invention is to provide an oxygen-absorbing resin having excellent oxygen absorption performance even in the absence of a transition metal catalyst.

The present invention provides an oxygen-absorbing resin which is a copolyester obtained by copolymerizing at least the following monomers (A) to (C).
Monomer (A): having a carbon atom bonded to both of the following structures (a) and (b) and bonded to one or two hydrogen atoms, the carbon atom being included in the alicyclic structure Dicarboxylic acid or a derivative thereof,
(A) a carbon-carbon double bond group,
(B) any one of a functional group containing a hetero atom or a linking group derived from the functional group, a carbon-carbon double bond group, or an aromatic ring;
Monomer (B): diol,
Monomer (C): at least one of a dicarboxylic acid having an aromatic ring or a derivative thereof, and a hydroxycarboxylic acid having an aromatic ring or a derivative thereof.
Moreover, this invention provides the oxygen absorptive resin composition containing the said oxygen absorptive resin.
Furthermore, the present invention provides an oxygen-absorbing container having an oxygen-absorbing layer comprising the oxygen-absorbing resin and the oxygen-absorbing resin composition.

  According to the oxygen-absorbing resin and the oxygen-absorbing resin composition of the present invention, while having excellent oxygen absorption performance even in the absence of a transition metal catalyst, while effectively suppressing the generation of low molecular weight odor components, An oxygen-absorbing material that has practical oxygen absorption performance has been realized.

The oxygen-absorbing resin of the present invention is an oxygen-absorbing resin that is a copolyester that can be obtained by copolymerizing at least the following monomers (A) to (C).
Monomer (A): having a carbon atom bonded to both of the following structures (a) and (b) and bonded to one or two hydrogen atoms, the carbon atom being included in the alicyclic structure Dicarboxylic acid or a derivative thereof,
(A) a carbon-carbon double bond group,
(B) any one of a functional group containing a hetero atom or a linking group derived from the functional group, a carbon-carbon double bond group, or an aromatic ring;
Monomer (B): diol,
Monomer (C): at least one of a dicarboxylic acid having an aromatic ring or a derivative thereof, and a hydroxycarboxylic acid having an aromatic ring or a derivative thereof.

  The alicyclic structure of the monomer (A) may be a heterocyclic structure containing a hetero atom in the ring. Further, it may be either monocyclic or polycyclic, and in the case of polycyclic, the ring not containing carbon may be an aromatic ring. The alicyclic structure is preferably a 3- to 12-membered monocyclic or polycyclic structure, more preferably a 5- or 6-membered monocyclic structure, and still more preferably a 6-membered monocyclic structure. Three- and four-membered ring structures have large strain energy and are easily opened to form chain structures. Moreover, since it becomes difficult to synthesize a 7-membered ring or more as the ring becomes larger, it is disadvantageous for industrial use. In particular, a 6-membered ring structure is preferable because it is energetically stable and can be easily synthesized. Furthermore, the alicyclic structure is bonded to both structure (a) and structure (b) and contains carbon atoms bonded to one or two hydrogen atoms, preferably carbon of structure (a) -A carbon double bond group is included in the alicyclic structure.

Examples of the functional group containing a hetero atom of the structure (b) or a linking group derived from the functional group include a hydroxyl group, a carboxyl group, a formyl group, an amide group, a carbonyl group, an amino group, an ether bond, an ester bond, and an amide bond. , Urethane bond, urea bond and the like. Preferably, the hetero atom is a functional group containing oxygen or a bonding group derived from the functional group, such as a hydroxyl group, a carboxyl group, a formyl group, an amide group, a carbonyl group, an ether bond, an ester bond, an amide bond, Urethane bond and urea bond. More preferred are a carboxyl group, a carbonyl group, an amide group, an ester bond and an amide bond. Since the monomer (A) having these functional groups and bonding groups can be prepared by a relatively simple synthesis reaction, it is advantageous for industrial use.
Examples of the aromatic ring of the structure (b) include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and a diphenyl ring. Preferred are a benzene ring and a naphthalene ring, and more preferred is a benzene ring.
Moreover, it is preferable that the carbon atom which couple | bonds with both structure (a) and (b) and is contained in the alicyclic structure has couple | bonded with one hydrogen atom. One of the two hydrogen atoms bonded to the carbon atom is substituted with, for example, an alkyl group, and as a result, the number of hydrogen atoms becomes one, so that the oxygen absorption performance is further improved. Derivatives include esters, acid anhydrides, acid halides, substituents, oligomers, and the like.

The monomer (A) is preferably a tetrahydrophthalic acid derivative or a tetrahydrophthalic anhydride derivative, more preferably a Δ ³ -tetrahydrophthalic acid derivative or a Δ ³ -tetrahydrophthalic anhydride derivative, still more preferably 4-methyl- Δ ³ -tetrahydrophthalic acid or 4-methyl-Δ ³ -tetrahydrophthalic anhydride. Tetrahydrophthalic anhydride derivatives can be synthesized very easily by Diels-Alder reaction of maleic anhydride with dienes such as butadiene, isoprene and piperylene. For example, cis-3-methyl-Δ ⁴ -tetrahydrophthalic anhydride and 4-methyl-Δ ⁴ -tetrahydroanhydride obtained by reacting a C ₅ fraction of naphtha mainly composed of trans-piperylene and isoprene with maleic anhydride. A mixture of phthalic acid is produced by stereoisomerization or structural isomerization.
These are inexpensive and commercially available, and are preferable in view of industrial use. 4-methyl - [delta ⁴ - tetrahydro phthalic anhydride and structural isomers of 4-methyl - [delta ³ - tetrahydrophthalic acid are preferred as the monomer (A). In addition, examples of the monomer (A) include exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride.

  Examples of the diol of the monomer (B) include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-butanediol, 1,4-butanediol, 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, α, α-dihydroxy-1,3-diisopropylbenzene, o-xylene glycol, m-xylene glycol, p-xylene glycol, α, α-dihydroxy-1, - diisopropylbenzene, hydroquinone, 4,4-dihydroxydiphenyl, naphthalenediol or derivatives thereof. Preferred are aliphatic diols such as diethylene glycol, triethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and more preferred is 1,4-butanediol. When 1,4-butanediol is used, the oxygen absorption performance of the resin is high, and the amount of decomposition products generated during the oxidation process is also small. These can be used alone or in combination of two or more.

Examples of the dicarboxylic acid having an aromatic ring of monomer (C) or a derivative thereof include benzene dicarboxylic acid such as phthalic anhydride, isophthalic acid and terephthalic acid, naphthalene dicarboxylic acid such as 2,6-naphthalenedicarboxylic acid, anthracene dicarboxylic acid, phenyl Examples include malonic acid, phenylene diacetic acid, phenylene dibutyric acid, bis (p-carboxyphenyl) methane, 4,4′-diphenyl ether dicarboxylic acid, p-phenylene dicarboxylic acid, and derivatives thereof. Preferably, it is a dicarboxylic acid in which a carboxyl group is directly bonded to an aromatic ring or a derivative thereof, and examples thereof include phthalic anhydride, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and derivatives thereof. Here, the derivatives include esters, acid anhydrides, acid halides, substituted products, oligomers, and the like. These can be used alone or in combination of two or more. In particular, the monomer (C) preferably contains terephthalic acid, and more preferably contains terephthalic acid and isophthalic acid.
Examples of the hydroxycarboxylic acid having an aromatic ring of the monomer (C) or a derivative thereof include 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,6-hydroxynaphthoic acid, 2-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, 4-hydroxyphenylacetic acid, 3- (4-hydroxyphenyl) butyric acid, 2- (4-hydroxyphenyl) butyric acid, 3-hydroxymethylbenzoic acid, 4-hydroxymethylbenzoic acid, 4- (hydroxy Methyl) phenoxyacetic acid, 4- (4-hydroxyphenoxy) benzoic acid, (4-hydroxyphenoxy) acetic acid, (4-hydroxyphenoxy) benzoic acid, mandelic acid, 2-phenyllactic acid, 3-phenyllactic acid, or derivatives thereof Etc. Preferably, it is a hydroxycarboxylic acid in which a carboxyl group and a hydroxyl group are directly bonded to an aromatic ring or a derivative thereof, such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, or a derivative thereof. Here, the derivatives include esters, acid anhydrides, acid halides, substituted products, oligomers, and the like. These can be used alone or in combination of two or more.
By copolymerizing the monomer (C) together with the monomers (A) and (B), gelation at the time of polycondensation can be suppressed, a copolyester having a high polymerization degree can be obtained, and the extrusion moldability is improved. Further, the Tg increases and the crystallinity increases, so that the handling property at the time of molding is improved. That is, it is possible to obtain a resin that has high oxygen absorption performance and that has few decomposition products and is excellent in extrusion moldability and handling properties.

The oxygen-absorbing resin of the present invention can be obtained by copolymerizing the monomers (A) to (C). As the copolymerization method, any method known to those skilled in the art can be used. For example, interfacial polycondensation, solution polycondensation, melt polycondensation and solid phase polycondensation.
When a dicarboxylic acid having an aromatic ring or a derivative thereof is used as the monomer (C), the monomer (A) unit in the resin is preferably 5 to 40 mol% of all the monomer units contained in the resin. More preferably, it is 7.5-35 mol%, More preferably, it is 10-30 mol%. At this time, it is preferable that a monomer (C) unit is 10-45 mol%, More preferably, it is 15-42.5 mol%, More preferably, it is 20-40 mol%. In the case of the above range, a resin having improved handling properties and excellent oxygen absorption performance can be obtained.
When a hydroxycarboxylic acid having an aromatic ring or a derivative thereof is used as the monomer (C), the composition ratio of the monomer (A) and (C) units can be appropriately selected by those skilled in the art.

Furthermore, together with the above monomers, aliphatic dicarboxylic acids, aliphatic hydroxycarboxylic acids, polyhydric alcohols, polycarboxylic acids, or derivatives thereof can be copolymerized as monomers. These can be used alone or in combination of two or more.
Aliphatic dicarboxylic acids and their derivatives include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, 3,3-dimethyl Pentanedioic acid or derivatives thereof may be mentioned.
Examples of the aliphatic hydroxycarboxylic acid and derivatives thereof include glycolic acid, lactic acid, hydroxypivalic acid, hydroxycaproic acid, hydroxyhexanoic acid, and derivatives thereof.
Examples of polyhydric alcohols and derivatives thereof include 1,2,3-propanetriol, sorbitol, 1,3,5-pentanetriol, 1,5,8-heptanetriol, trimethylolpropane, pentaerythritol, neopentyl glycol, 3 , 5-dihydroxybenzyl alcohol, or derivatives thereof.
Examples of the polyvalent carboxylic acid and its derivatives include 1,2,3-propanetricarboxylic acid, meso-butane-1,2,3,4-tetracarboxylic acid, citric acid, trimellitic acid, pyromellitic acid, and these Derivatives.

A polymerization catalyst is not necessarily required, but a normal polyester polymerization catalyst such as a titanium-based, germanium-based, antimony-based, tin-based, or aluminum-based catalyst can be used. Further, known polymerization catalysts such as nitrogen-containing basic compounds, boric acid and boric acid esters, and organic sulfonic acid compounds can also be used.
Furthermore, various additives, such as coloring inhibitors, such as a phosphorus compound, and antioxidant, can also be added in the case of superposition | polymerization. By adding an antioxidant, it is possible to suppress oxygen absorption during polymerization and subsequent molding processing, and thus it is possible to suppress a decrease in performance of the oxygen-absorbing resin.
In the oxygen-absorbing resin of the present invention, the ratio of the alicyclic structure is preferably 0.1 to 10 meq / g, more preferably 0.2 to 7 meq / g. When the amount is within the above range, an oxygen-absorbing resin having practical oxygen-absorbing performance and little change in hue or lowering in strength even after oxygen absorption is obtained.
The number average molecular weight of the oxygen-absorbing resin of the present invention is preferably 1000 to 1000000, and more preferably 2000 to 200000. In the case of the number average molecular weight within the above range, a film excellent in processability and durability can be formed.
The oxygen-absorbing resin of the present invention may be used alone or in combination of two or more.
The oxygen-absorbing resin of the present invention can be used not only as a resin for melt processing such as extrusion molding or injection molding but also as a paint by dissolving in an appropriate solvent. When used as a paint, for example, an isocyanate curing agent can be blended and used as an adhesive for a two-component curable dry laminate.

Since the oxygen-absorbing resin of the present invention has extremely high reactivity with oxygen, practical oxygen-absorbing performance can be expressed without performing radiation treatment in the absence of a transition metal catalyst. The reactivity of the oxygen-absorbing resin of the present invention is activated by the thermal history received by the resin during resin synthesis and molding. It is also possible to increase the reactivity by positively applying heat, or to suppress the reaction by suppressing the heat history. For example, when the reactivity is suppressed, the reactivity can be increased by performing a radiation irradiation treatment.
The radiation used in the oxygen-absorbing resin of the present invention is a particle beam such as an electron beam, a proton beam and a neutron beam, and an electromagnetic wave such as a gamma ray, an X-ray, a visible ray and an ultraviolet ray. Among these, low energy radiation such as visible light and ultraviolet light is particularly preferable, and ultraviolet light is more preferable. As the ultraviolet irradiation condition, for example, UV-A with an integrated light quantity of 100 to 10,000 mJ / cm ² is preferable. The timing of ultraviolet irradiation is not particularly limited, but when used as an oxygen-absorbing container, in order to effectively utilize the oxygen-absorbing performance, the container is preferably molded and immediately before being filled and sealed.

The oxygen-absorbing resin of the present invention preferably has no allyl hydrogen other than the alicyclic structure. Allyl hydrogen is relatively easy to extract and is therefore susceptible to oxygen attack. When allyl hydrogen is present in the straight chain structure other than the alicyclic structure, a low molecular weight decomposition component is likely to occur due to molecular chain scission accompanying oxygen oxidation at the allyl position.
In addition to the highly reactive alicyclic structure derived from the monomer (A), the resin of the present invention may contain another alicyclic structure, and the other alicyclic structure contains the monomer (A). Allyl hydrogen having a relatively low reactivity which is not included in the structure may be included. In the case of such a resin structure, the radical transfer generated in the highly reactive alicyclic structure derived from the monomer (A) activates allyl hydrogen in the alicyclic ring, which has a relatively low reactivity, and has an oxygen absorption performance. Since it may improve, it is preferable.

The oxygen-absorbing resin of the present invention may be further blended with another thermoplastic resin to form an oxygen-absorbing resin composition. Any thermoplastic resin can be used as the thermoplastic resin.
For example, 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, or ethylene, propylene, Random or block copolymers of α-olefins such as 1-butene and 4-methyl-1-pentene, polyolefins such as cyclic olefin polymer (COP) and cyclic olefin copolymer (COC), maleic anhydride grafted polyethylene and maleic anhydride Acid-modified polyolefins such as acid-grafted polypropylene, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-vinyl chloride copolymers, ethylene- (meth) acrylic acid copolymers and their ionic cross-linked products (ionomers) ), Ethylene Ethylene-vinyl compound copolymers such as methyl tacrylate copolymer, styrene resins such as polystyrene, acrylonitrile-styrene copolymer, α-methylstyrene-styrene copolymer, polymethyl acrylate, polymethyl methacrylate, etc. Polyvinyl compound, nylon 6, nylon 66, nylon 610, nylon 12, polyamide such as polymetaxylylene adipamide (MXD6), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), Polyethylene naphthalate (PEN), glycol modified polyethylene terephthalate (PETG), polyethylene succinate (PES), polybutylene succinate (PBS), polylactic acid, polyglycolic acid, polycaprolac Down, polyesters such as polyhydroxyalkanoates, polycarbonate, polyether or a mixture thereof such as polyethylene oxide.
Preferably, the thermoplastic resin is polyethylene, particularly low density polyethylene. More preferably, it is a linear low density polyethylene obtained by copolymerizing ethylene and 1-alkene. Films and sheets formed by blending the oxygen-absorbing resin and linear low-density polyethylene are excellent in impact resistance. As the 1-alkene, 1-propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and a mixture thereof can be used.
The 1-alkene to be copolymerized is preferably 2 to 30% by weight, more preferably 2 to 20% by weight.
In the copolymerization, either a conventional Ziegler-Natta catalyst or a single-site catalyst can be selected as long as it has a desired molecular structure, but polymerization is performed using a single-site catalyst. Thus, it is possible to reliably prevent the fluctuation of the copolymer composition ratio over the respective molecular weight components. As a result, even when the molecular structure becomes uniform and the oxidation of the thermoplastic resin is induced due to the radical chain transfer of the oxygen-absorbing resin, the oxidation proceeds uniformly between the molecular chains. Since generation | occurrence | production of a decomposition product can be suppressed, it is preferable. Suitable catalysts include metallocene catalysts. As the other catalyst, an olefin polymerization catalyst positioned as a post metallocene catalyst, particularly a phenoxyimine catalyst (FI catalyst) is suitable.

Examples of the linear low density polyethylene include a copolymer of ethylene and 1-butene, a copolymer of ethylene and 1-hexene, and a copolymer of ethylene and 1-octene using a metallocene catalyst as a polymerization catalyst. Of these, a copolymer of ethylene and 1-olefin is preferred.
These resins may be used alone or in combination of two or more.
The above-described polymerization of the resin with a single site catalyst may be carried out by any industrially feasible method, but is preferably carried out by a liquid phase method because it is most widely used.
The thermoplastic resins may be used alone or in combination of two or more.
The ratio of the alicyclic structure in the oxygen-absorbing resin composition is preferably 0.1 to 10 meq / g, more preferably 0.2 to 7 meq / g. When the amount is within the above range, an oxygen-absorbing resin composition having practical oxygen absorption performance and less hue change and strength reduction after oxygen absorption is obtained.

The oxygen-absorbing resin and oxygen-absorbing resin composition of the present invention can further contain various additives such as a radical initiator and a photosensitizer.
Examples of the radical initiator and photosensitizer include benzoin such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether and alkyl ethers thereof; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2- Diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1 Acetophenones such as -one; anthraquinones such as 2-methylanthraquinone and 2-amylanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone Emissions, 2,4 thioxanthones such as diisopropyl thioxanthone, acetophenone dimethyl ketal, ketal such as benzil dimethyl ketal; what is commonly known as photoinitiators such as benzophenones or xanthones such as benzophenone is used. Such photoradical initiators can be used in combination with one or more known and commonly used photopolymerization accelerators such as benzoic acid type or tertiary amine type.
Other additives include fillers, colorants, heat stabilizers, weathering stabilizers, antioxidants, anti-aging agents, light stabilizers, UV absorbers, antistatic agents, lubricants such as metal soap and wax, An additive such as a quality resin or rubber may be mentioned, and it can be added according to a formulation known per se. For example, by incorporating a lubricant, the bite of the resin into the screw is improved. Lubricants include metal soaps such as magnesium stearate and calcium stearate, hydrocarbons such as fluid, natural or synthetic paraffin, micro wax, polyethylene wax and chlorinated polyethylene wax, and fatty acids such as stearic acid and lauric acid. , Stearic acid amide, valmitic acid amide, oleic acid amide, esylic acid amide, fatty acid monoamide type or bisamide type such as ethylene bisstearamide, butyl stearate, hydrogenated castor oil, ethylene glycol mono An ester type such as stearate and a mixed system thereof are generally used.

  The oxygen-absorbing resin and oxygen-absorbing resin composition of the present invention can be used for oxygen absorption in a sealed package in the form of powder, granules or sheets. Moreover, it can mix | blend with resin and rubber | gum for liners, gaskets, or coating formation, and can be used for residual oxygen absorption in a package. In particular, the oxygen-absorbing resin and the oxygen-absorbing resin composition of the present invention are preferably used as an oxygen-absorbing container in the form of a laminate composed of at least one layer containing the same and another resin layer.

The oxygen-absorbing container of the present invention has at least one layer (hereinafter referred to as an oxygen-absorbing layer) made of the above-described oxygen-absorbing resin and oxygen-absorbing resin composition.
The layers other than the oxygen absorbing layer constituting the oxygen-absorbing container of the present invention can be appropriately selected from thermoplastic resins, thermosetting resins, inorganic materials such as metals, paper, and the like depending on the use mode and required functions. For example, the thermoplastic resin enumerated as an example of the thermoplastic resin which can be mix | blended with the above-mentioned oxygen-absorbing resin of this invention, metal foil, and an inorganic vapor deposition film can be mentioned.
In the oxygen-absorbing container of the present invention, it is preferable to provide an oxygen barrier layer at least outside the oxygen-absorbing layer in order to further enhance the effect of the oxygen-absorbing resin or oxygen-absorbing resin composition. With such a configuration, it is possible to effectively absorb oxygen permeating into the container from the outside and oxygen remaining in the container, and to keep the oxygen concentration in the container low for a long period of time.
An oxygen barrier resin can be used for the oxygen barrier layer. An example of the oxygen barrier resin is an ethylene-vinyl alcohol copolymer (EVOH). For example, an ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol%, preferably 25 to 50 mol%, has a saponification degree of 96 mol% or more, preferably 99 mol% or more. A saponified copolymer obtained by saponification is used. Other examples of the oxygen barrier resin include polymetaxylylene adipamide (MXD6), polyglycolic acid and the like. Moreover, the nanocomposite material which mix | blended inorganic layered compounds, such as montmorillonite, etc. with said oxygen barrier resin, another polyamide resin, etc. can be used conveniently.

In particular, when the oxygen-absorbing container of the present invention is a film container such as a pouch, a metal foil such as a light metal foil such as aluminum, an iron foil, a tin foil, or a surface-treated steel foil, a biaxially stretched PET film by a vapor deposition method A metal thin film, a metal oxide thin film, or a diamond-like carbon thin film formed on a substrate such as the above can be used as the oxygen barrier layer. In addition, a barrier coating film obtained by applying an oxygen barrier coating to a base film such as a biaxially stretched PET film can also be used.
Examples of the material constituting the metal thin film include iron, aluminum, zinc, titanium, magnesium, tin, copper, and silicon. Aluminum is particularly preferable.
Examples of the material constituting the metal oxide thin film include silica, alumina, zirconium oxide, titanium oxide, and magnesium oxide. Silica and alumina are particularly preferable. Note that two or more materials may be used in combination, and the same or different materials may be laminated.
Such a thin film can be deposited by, for example, vacuum vapor deposition, sputtering, ion plating, physical vapor deposition (PVD) such as laser ablation, plasma chemical vapor deposition, thermal chemical vapor deposition, or the like. Further, it is performed by a known method such as a chemical vapor deposition method (CVD method) such as a photochemical vapor deposition method.
As a material constituting the oxygen barrier coating, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, poly (meth) acrylic acid, polyallylamine, polyacrylamide, polysaccharides and other high hydrogen bond resins, vinylidene chloride resin, An epoxyamine etc. are mentioned. It is also preferable to blend an inorganic layered compound such as montmorillonite with these materials.
Moreover, what has an oxygen absorptive barrier layer which mix | blended oxygen absorptive resin and an oxygen absorptive resin composition with the above-mentioned oxygen barrier resin as an oxygen absorptive container of this invention is also preferable. In this case, since it is not always necessary to provide another oxygen barrier single layer and oxygen absorption single layer, the layer structure can be simplified.

For the production of the oxygen-absorbing container, a molding method known per se can be used.
For example, a multilayer film, a multilayer sheet, a multilayer parison, a multilayer pipe, or the like can be formed by performing extrusion molding using a multilayer multiple die using the number of extruders corresponding to the type of resin. In addition, a multilayer preform for bottle molding can be manufactured by co-injection molding such as a simultaneous injection method or a sequential injection method using the number of injection molding machines corresponding to the type of resin. By further processing such a multilayer film, parison, and preform, an oxygen-absorbing multilayer container can be obtained.
Packaging materials such as films can be used as pouches in various forms and as lid materials for tray cups. Examples of the pouch include three- or four-side sealed flat pouches, gusseted pouches, standing pouches, pillow packaging bags, and the like. Bag making can be performed by a known bag making method. Moreover, a cup or tray-shaped packaging container can be obtained by subjecting the film or sheet to means such as vacuum forming, pressure forming, bulging forming, or plug assist forming.
For the production of a multilayer film or a multilayer sheet, an extrusion coating method or sandwich lamination can be used. Moreover, the single layer and multilayer film which were formed previously can also be laminated | stacked by dry lamination. For example, a transparent vapor-deposited film is laminated by dry lamination on a three-layer coextruded film consisting of a thermoplastic resin layer / oxygen absorbing layer / thermoplastic resin (sealant) layer, biaxially stretched PET film / aluminum foil laminated by dry lamination Oxygen-absorbing polyethylene-based single layer film on barrier coating film / polyethylene two-layer film by coating two layers of oxygen absorption layer / sealant layer on the two-layer film by extrusion through anchor agent or laminated by dry lamination Examples of the method include sandwich lamination via a resin composition, but are not limited thereto.

Moreover, a parison, a pipe, or a preform is pinched off by a pair of split molds, and a bottle or a tube can be easily formed by blowing a fluid into the inside. Moreover, after cooling a pipe and a preform, it is heated to a stretching temperature, stretched in the axial direction, and blow stretched in the circumferential direction by fluid pressure to obtain a stretch blow bottle or the like.
The oxygen-absorbing container of the present invention effectively blocks oxygen permeating from the outside through the container wall and absorbs oxygen remaining in the container. Therefore, it is useful as a container that keeps the oxygen concentration in the container at a low level for a long period of time, prevents the quality deterioration related to the oxygen in the contents, and improves the shelf life.
In particular, content that easily deteriorates in the presence of oxygen, such as coffee beans, tea leaves, snacks, rice crackers, raw and half-baked confectionery, fruits, nuts, vegetables, fish and meat products, kneaded products, dried fish, smoked and boiled , Raw rice, cooked rice, infant food, jam, mayonnaise, ketchup, cooking oil, dressing, sauces, dairy products, beverages such as beer, wine, fruit juice, green tea, coffee, etc., pharmaceuticals, cosmetics, electronic parts in others However, it is not limited to these examples.

Hereinafter, the present invention will be specifically described by way of examples. Each value was measured by the following method.
(1) Number average molecular weight (Mn) and molecular weight distribution index (Mw / Mn)
It was measured in terms of polystyrene by gel permeation chromatography (GPC, manufactured by Tosoh Corporation; HLC-8120 GPC). Chloroform was used as the solvent.
(2) Composition ratio of each monomer unit in the copolyester resin The composition ratio of the acid component contained in the resin was calculated by nuclear magnetic resonance spectroscopy ( ¹ H-NMR, manufactured by JEOL Datum; EX270). The content ratio of isophthalic acid in the monomer (C) is calculated from methyltetrahydrophthalic anhydride based on the signal area ratio of the benzene ring proton derived from terephthalic acid (8.1 ppm) and the benzene ring proton derived from isophthalic acid (8.7 ppm). Area ratio of signals of methylene protons (4.1-4.2 ppm) adjacent to the derived ester group and methylene protons (4.3-4.4 ppm) adjacent to the ester group derived from terephthalic acid and isophthalic acid From the above, the composition ratio of the acid component was calculated. The solvent used was deuterated chloroform containing tetramethylsilane as a reference substance.
At this time, the composition ratio of the copolyester resin was almost equal to the charged amount (molar ratio) of each monomer used for the polymerization.
(3) Handling property The presence or absence of blocking due to stickiness of the resin was evaluated. In the extruder hopper, pellets were blocked, and x was not blocked.
(4) Oxygen absorption amount The cut specimen was charged into an oxygen-impermeable steel foil laminated cup having an internal volume of 85 cm ³ , heat-sealed with an aluminum foil laminated film lid, and stored in an atmosphere at 22 ° C. The oxygen concentration in the cup after storage for a certain period of time was measured with a micro gas chromatograph (manufactured by Agilent Technologies; M200), and the amount of oxygen absorbed per 1 cm ^{2 of} resin was calculated.
(5) Volatile decomposition product amount The cut test piece was sealed in a vial for head space gas chromatography having an internal volume of 22 cm ³ and stored in an atmosphere at 22 ° C. The amount of volatile decomposition products in the vial after storage for a certain period of time was measured with a gas chromatograph apparatus (Agilent Technology; 6890 series, column HP-5) equipped with a headspace sampler (Hewlett Packard; HP 7694) and absorbed oxygen. The amount of volatile decomposition products per 1 ml was calculated.

Example 1
Methyltetrahydrophthalic anhydride containing 45% by weight of 4-methyl-Δ ³ -tetrahydrophthalic anhydride as monomer (A) in a 500 ml separable flask equipped with a stirrer, nitrogen inlet tube and Dean-Stark type water separator 83.1 g of acid (manufactured by Hitachi Chemical Co., Ltd .; HN-2200), 126.3 g of terephthalic acid (manufactured by Wako Pure Chemical Industries, Ltd.) as monomer (C), and 1,4-butanediol (Wako Pure Chemical Industries, Ltd.) as monomer (B) 227.1 g, isopropyl titanate (manufactured by Kishida Chemical Co., Ltd.), and 20 ml of toluene, respectively, were reacted for about 6 hours while removing water produced at 150 ° C. to 200 ° C. in a nitrogen atmosphere. I let you. Subsequently, toluene was removed from the reaction system, and finally polymerization was performed at 200 ° C. under a reduced pressure of 0.1 kPa for about 6 hours to obtain a rubbery copolyester resin D. At this time, Mn was about 8600 and Mw / Mn was 6.5.
When the obtained resin D was stored at 50 ° C. in a nitrogen atmosphere for 0.5 days, a resin excellent in handling property that was crystallized and was not sticky and difficult to block was obtained. Further, this was formed into a sheet having an average thickness of about 270 μm by a hot press at 200 ° C., and a 20 cm ² test piece was cut out and used for evaluation of the oxygen absorption amount. The results are shown in Table 1.

(Example 2)
Polymerization was carried out in the same manner as in Example 1 except that the monomer (A) was changed to 104.7 g and the monomer (C) was changed to 104.7 g to obtain a rubbery copolyester resin E. At this time, Mn was about 8800 and Mw / Mn was 9.3.
When the obtained resin E was stored at 50 ° C. in a nitrogen atmosphere for 0.5 days, it was crystallized to obtain a resin that was not sticky and difficult to block. Further, this was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

(Example 3)
Polymerization was carried out in the same manner as in Example 1 except that 125.6 g of the monomer (A) and 83.7 g of the monomer (C) were used, and a rubbery copolyester resin F was obtained. At this time, Mn was about 6000 and Mw / Mn was 7.7.
When the obtained resin F was stored in a nitrogen atmosphere at 50 ° C. for 0.5 days, it was crystallized to obtain a resin that was not sticky and difficult to block. Further, this was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

Example 4
Polymerization was carried out in the same manner as in Example 2 except that 94.2 g of terephthalic acid and 10.5 g of isophthalic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were used as the monomer (C) to obtain a rubbery copolyester resin G. At this time, Mn was about 8200 and Mw / Mn was 9.5.
When the obtained resin G was stored at 50 ° C. in a nitrogen atmosphere for 0.5 days, it was crystallized to obtain a resin that was not sticky and difficult to block. Further, this was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

(Example 5)
Polymerization was carried out in the same manner as in Example 2 except that 83.7 g of terephthalic acid and 20.9 g of isophthalic acid were used as the monomer (C) to obtain a rubbery copolyester resin H. At this time, Mn was about 7900 and Mw / Mn was 10.3.
When the obtained resin H was stored at 50 ° C. in a nitrogen atmosphere for 0.5 days, it was crystallized and a resin that was not sticky and difficult to block was obtained. Further, this was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
Polymerization was carried out in the same manner as in Example 1 except that 209.4 g of HN-2200 was charged as the monomer (A) and the monomer (C) was not used, and a rubbery polyester resin I was obtained. At this time, Mn was about 5200, Mw / Mn was very large as 27, and a small amount of gel was contained in the resin.
The obtained resin I was stored at 50 ° C. in a nitrogen atmosphere for 0.5 days, but there was no particular change in appearance and no crystallization occurred. Moreover, since the surface was sticky and easily blocked, the handling property was inferior. An attempt was made to form a sheet by hot pressing, but this was not possible.

(Comparative Example 2)
Polymerization was carried out in the same manner as in Example 1 except that 74.4 g of succinic acid (manufactured by Kishida Chemical Co., Ltd.) was used as the monomer (C) to obtain a rubbery copolyester resin J. At this time, Mn was about 4800 and Mw / Mn was 10.1.
The obtained resin J was stored in a nitrogen atmosphere at 50 ° C. for 0.5 days, but there was no particular change in appearance and no crystallization occurred. Moreover, since the surface was sticky and easily blocked, the handling property was inferior.
This was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

(Example 6)
50 parts by weight of resin E and 50 parts by weight of a single-site catalytic linear low density polyethylene (LLDPE) resin (Evolution SP0511, manufactured by Prime Polymer Co., Ltd.) as a thermoplastic resin, a laboratory mixing extruder (manufactured by Toyo Seiki Seisakusho; CS-194AV) Was melt kneaded at 200 ° C. and dried in a nitrogen atmosphere at 50 ° C. for 0.5 days to obtain a resin blend 1.
The obtained resin blend 1 was formed into a sheet having an average thickness of about 270 μm with a hot press at 200 ° C., and 20 cm ² and 5 cm ² test pieces were cut out and used for evaluation of oxygen absorption and volatile decomposition products. did. The results are shown in Table 1.

(Example 7)
A resin blend 2 was obtained by carrying out the same treatment as in Example 6 except that 50 parts by weight of the resin E and 50 parts by weight of a low density polyethylene (LDPE) resin (Sumikasen L705, manufactured by Sumitomo Chemical Co., Ltd.) were used as the thermoplastic resin.
The obtained resin blend 2 was subjected to the same evaluation as in Example 6. The results are shown in Table 1.

(Example 8)
Resin blend 3 was obtained by performing the same treatment as in Example 6 except that 50 parts by weight of resin G and 50 parts by weight of LLDPE resin were used as the thermoplastic resin.
The obtained resin blend 3 was subjected to the same evaluation as in Example 6. The results are shown in Table 1.

Example 9
Resin blend 4 was obtained by performing the same treatment as in Example 6 except that 50 parts by weight of resin G and 50 parts by weight of LDPE resin were used as the thermoplastic resin.
The obtained resin blend 4 was subjected to the same evaluation as in Example 6. The results are shown in Table 1.

(Example 10)
Resin blend 5 was obtained by carrying out the same treatment as in Example 6 except that 50 parts by weight of resin G and 50 parts by weight of polybutylene terephthalate copolymer (PBT) resin (Duranex 600LP, manufactured by Polyplastics) were used as the thermoplastic resin. Obtained.
The obtained resin blend 5 was subjected to the same evaluation as in Example 6. The results are shown in Table 1.

(Example 11)
Resin Blend 6 was prepared by performing the same treatment as in Example 6 except that 50 parts by weight of resin G and 50 parts by weight of polybutylene succinate (PBS) resin (GS-pl AZ91T, manufactured by Mitsubishi Chemical Corporation) were used as the thermoplastic resin. Obtained.
The obtained resin blend 6 was subjected to the same evaluation as in Example 6. The results are shown in Table 1.

(Example 12)
1 kg of Resin E was prepared and stored at 40 ° C. in a nitrogen atmosphere for 0.5 days for crystallization. This pulverized product was formed into a film by a T-die method using a lab plast mill (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a molding temperature of 200 ° C., and an ethylene-methacrylic acid copolymer resin (Nucrel N1035, manufactured by Mitsui DuPont Polychemical Co., Ltd.). 3 layer coextruded film (N1035 (15) / resin E (60) / N1035 (15) (the thickness in parentheses is the thickness of each layer (μm)). Also, 12 μm transparent vapor-deposited biaxially stretched polyethylene terephthalate ( PET) film (manufactured by Toppan Printing Co., Ltd .; GL-AEH) and an LDPE film (manufactured by Tamapoly Co., Ltd .; V-1) that has been previously corona treated on one side, the vapor deposition surface of the vapor deposition film and the corona treatment surface of the LDPE film face each other. After bonding using a two-component urethane-based adhesive (manufactured by Takeda Pharmaceutical Company Limited; Takelac A-315 + Takenate A-50) The film was cured at 50 ° C. for 3 days to obtain a transparent vapor-deposited PET / LDPE two-layer film, which was bonded to the LDPE side of the obtained two-layer film by thermal lamination to absorb oxygen. A laminated film was obtained.
The obtained laminated film was overlapped so that the three-layer coextruded film was opposed to each other, and a transparent flat pouch was obtained by heat-sealing four sides. Since this flat pouch has a deoxygenating function in the pouch, it is excellent in the preservation of contents.

(Example 13)
1 kg of Resin E was prepared and stored at 40 ° C. in a nitrogen atmosphere for 0.5 days for crystallization. Using a twin screw extruder (TEM-35B, manufactured by Toshiba Machine Co., Ltd.) in which 50 parts by weight of this pulverized product and 50 parts by weight of LLDPE resin as a thermoplastic resin were dry blended and a strand die was attached to the exit part, A strand was drawn at a molding temperature of 200 ° C. while pulling a high vacuum vent at 100 rpm to obtain a resin blend 7. This resin has a high melt viscosity and excellent extrudability.
Further, the resin blend 7 was formed into a film by a T-die method using a lab plast mill (manufactured by Toyo Seiki Co., Ltd.) at a molding temperature of 200 ° C., and a three-layer coextruded film (SP0511 (15) / resin blend with LLDPE resin) Product 7 (60) / SP0511 (15) (the thickness in parentheses is the thickness of each layer (μm)) Further, an oxygen-absorbing laminated film was produced in the same manner as in Example 12 to obtain a flat pouch. Since the pouch has a deoxygenating function in the pouch, the pouch is excellent in the preservation of the contents.

(Example 14)
1 kg of Resin G was prepared, and the same operation as in Example 13 was performed to obtain a resin blend 8. This resin has a high melt viscosity and excellent extrudability.
Further, the resin blend 8 was formed into a film by a T-die method using a lab plast mill (manufactured by Toyo Seiki Co., Ltd.) at a molding temperature of 200 ° C., and a three-layer coextruded film (SP0511 (15) / resin blend) with an LLDPE resin Product 8 (60) / SP0511 (15) (the thickness in parentheses is the thickness (μm) of each layer) Further, an oxygen-absorbing laminated film was produced in the same manner as in Example 12 to obtain a flat pouch. Since the pouch has a deoxygenating function in the pouch, the pouch is excellent in the preservation of the contents.

Claims (17)

Oxygen-absorbing resin, which is a random copolymerized polyester that can be obtained by copolymerizing at least the following monomers (A) to (C):
Monomer (A): a carbon atom attached to both of the following structures (a) and (b), have one or two of said carbon atoms bonded with hydrogen atoms, said carbon atom alicyclic Tetrahydrophthalic acid derivative or tetrahydrophthalic anhydride derivative contained in the structure,
(A) a carbon-carbon double bond group,
(B) a functional group containing a hetero atom or a linking group derived from the functional group,
Monomer (B): diol,
Monomer (C): at least one of a dicarboxylic acid having an aromatic ring or a derivative thereof, and a hydroxycarboxylic acid having an aromatic ring or a derivative thereof. The oxygen-absorbing resin according to claim 1, wherein a carboxyl group or a hydroxyl group contained in the monomer (C) is directly bonded to the aromatic ring.   The oxygen-absorbing resin according to claim 2, wherein the monomer (C) contains phthalic acid or a derivative thereof.   The oxygen-absorbing resin according to claim 3, wherein the monomer (C) contains terephthalic acid.   The oxygen-absorbing resin according to claim 4, wherein the monomer (C) contains terephthalic acid and isophthalic acid. The oxygen-absorbing resin according to claim 1, wherein the tetrahydrophthalic acid derivative or the tetrahydrophthalic anhydride derivative includes a Δ ³ -tetrahydrophthalic acid derivative or a Δ ³ -tetrahydrophthalic anhydride derivative. The oxygen absorption according to claim 6, wherein the Δ ³ -tetrahydrophthalic acid derivative or Δ ³ -tetrahydrophthalic anhydride derivative comprises 4-methyl-Δ ³ -tetrahydrophthalic acid or 4-methyl-Δ ³ -tetrahydrophthalic anhydride. Resin.   The oxygen-absorbing resin according to any one of claims 1 to 7, wherein the monomer (B) is an aliphatic diol.   The oxygen-absorbing resin according to any one of claims 1 to 8, wherein the monomer (B) contains an aliphatic diol of C4 or higher.   The oxygen-absorbing resin according to any one of claims 1 to 9, which does not contain a transition metal salt as an oxidation catalyst.   The oxygen absorptive resin composition containing the oxygen absorptive resin of any one of Claims 1-10.   The oxygen-absorbing resin composition according to claim 11, further comprising a thermoplastic resin.   The oxygen-absorbing resin composition according to claim 12, wherein the thermoplastic resin is polyethylene.   The oxygen-absorbing resin composition according to claim 13, wherein the polyethylene is linear low-density polyethylene.   The oxygen-absorbing resin composition according to any one of claims 11 to 14, which does not contain a transition metal salt as an oxidation catalyst.   An oxygen-absorbing container having an oxygen-absorbing layer comprising the oxygen-absorbing resin according to any one of claims 1 to 10 or the oxygen-absorbing resin composition according to any one of claims 11 to 15.   The oxygen-absorbing container according to claim 16, further comprising an oxygen barrier layer outside the oxygen-absorbing layer.