JP4682704B2 - Oxygen absorbing multilayer tube - Google Patents

Description

  The present invention relates to a multilayer tube formed by overlapping a plurality of layers. More specifically, the present invention relates to an oxygen-absorbing multilayer tube that is excellent in oxygen-absorbing property and gas barrier property and that can maintain the quality of the contents well over a long period of time.

  Tube containers are widely used as containers for various foods such as kneaded wasabi and kashikara, cosmetics, pharmaceuticals, sanitary materials such as toothpaste, and chemicals such as adhesives. These tube-shaped containers have been used in the past to contain an aluminum foil as a gas barrier material layer in order to prevent the contents from being deteriorated, particularly from oxygen. These tubes have been used especially as containers for pharmaceuticals and the like because sufficient gas barrier properties can be obtained with aluminum foil.

However, in recent years, due to the problem of waste disposal, multilayer tubes laminated with aluminum foil tend to be replaced with gas barrier resin laminated multilayer tubes.
As the gas barrier resin, gas barrier resins such as ethylene-vinyl alcohol copolymer and metaxylylene adipamide, silica-deposited thermoplastic resin films, and the like have been proposed.
However, by changing the aluminum foil to a gas barrier resin, the oxygen gas impermeability is reduced, that is, oxygen gas is likely to permeate inside the multilayer tube, and the contents are likely to be altered. There was found.

  For this reason, it has been proposed to provide an oxygen-absorbing layer as one of the layers constituting the multilayer tube. For example, Patent Document 1 proposes an oxygen barrier resin composition comprising a saponified ethylene-vinyl acetate copolymer and an oxidation catalyst such as cobalt stearate. In Patent Documents 2 and 3, an oxygen barrier resin composition in which a composition comprising a polyolefin and an oxidation catalyst is dispersed in a saponified ethylene-vinyl acetate copolymer, or a saponified polyolefin and ethylene-vinyl acetate copolymer. An oxygen barrier resin composition comprising a product and an oxidation catalyst is disclosed. In Patent Document 4, iron powder such as reduced iron powder, pulverized products such as cast iron and steel, and ground products are used as the main agent, and oxygen absorbers using metal halides and alkali agents as thermoplastic resins are used as thermoplastic resins. It consists of a dispersed oxygen absorber layer, a saponified ethylene-vinyl acetate copolymer, a gas barrier thermoplastic resin such as polyamide such as MX nylon or amorphous nylon, or an inorganic oxide vapor deposited film such as a silica vapor deposited film. A deoxygenating multilayer tube having a gas barrier layer is disclosed.

  However, these conventional multi-layer tubes have a problem that peeling between the oxygen absorbent layer and the gas barrier layer is likely to occur, and the capacity of the oxygen absorbent used is not sufficient. There is a problem that the quality cannot be maintained for a long time. Moreover, it cannot be said that there is no possibility that the contents are contaminated by migration or extraction of the compounds contained in the resin layer constituting the tube. Furthermore, when transparency is required for the container, a decrease in transparency due to the use of iron powder or the like is not preferable.

JP-A-4-21444 Japanese Patent Laid-Open No. 5-156095 Japanese Patent Laid-Open No. 5-170980 JP 2002-103490 A

  Accordingly, an object of the present invention is a multilayer tube that is excellent in oxygen absorption and gas barrier properties, has no problem of delamination between layers constituting the multilayer tube, and can maintain the quality of the contents well over a long period of time. Is to provide.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has used a conjugated diene polymer cyclized product and an ethylene-vinyl alcohol copolymer as an active ingredient of an oxygen-absorbing gas barrier resin layer. The present inventors have found that a multilayer tube suitable for the above-mentioned purpose can be obtained, and have completed the present invention based on this finding.

Thus, according to the present invention, the tube is composed of a mouth and neck portion having a spout for contents and a body portion connected to the mouth and neck portion and having its tail end formed into a fishtail shape, and at least the body portion, The inner resin layer, the conjugated diene polymer cyclized product and the ethylene-vinyl alcohol copolymer, which are laminated in the following order from the inner side to the outer side, the oxygen-absorbing gas barrier resin layer and the surface resin layer are essential components. An oxygen-absorbing multi-layer tube is provided as a layer.
In the oxygen-absorbing multi-layer tube of the present invention, the mouth-and-neck portion includes an inner surface resin layer, a conjugated diene polymer cyclized product, and an ethylene-vinyl alcohol copolymer that are laminated in the following order from the inner side to the outer side. An oxygen-absorbing gas barrier resin layer and a surface resin layer can be included as essential constituent layers.

Moreover, the oxygen-absorbing multilayer tube of the present invention may have a deodorant layer.
In the oxygen-absorbing multilayer tube of the present invention, it is preferable that the unsaturated bond reduction rate of the conjugated diene polymer cyclized product is 10% by weight or more.
In the oxygen-absorbing multilayer tube of the present invention, the ethylene-vinyl alcohol copolymer has an oxygen transmission rate of 0.2 to ² cc · 20 μm / m ² · day · atm (@ 20 ° C.). preferable.
Further, in the oxygen-absorbing multilayer tube of the present invention, the weight ratio of the conjugated diene polymer cyclized product and the ethylene-vinyl alcohol copolymer in the oxygen-absorbing gas barrier resin layer (conjugated diene polymer cyclized product / ethylene-vinyl alcohol). The copolymer) is preferably 50/50 to 5/95.

ADVANTAGE OF THE INVENTION According to this invention, the oxygen absorption multilayer tube which is excellent in oxygen absorptivity and gas barrier property, and the peeling strength between layers, and can maintain the quality of the content favorably over a long period of time is provided.
The oxygen-absorbing multilayer tube of the present invention is suitable as a container for various foods such as kneaded wasabi and kashikara, hygiene materials such as cosmetics, pharmaceuticals and toothpaste, and chemicals such as adhesives.

  The oxygen-absorbing multilayer tube of the present invention is a tube comprising a mouth / neck part having a spout for contents and a body part that is connected to the mouth / neck part and has its tail end formed into a fishtail shape. Part is laminated in the following order from the inner side to the outer side, an oxygen-absorbing gas barrier resin layer and a surface resin layer containing a conjugated diene polymer cyclized product and an ethylene-vinyl alcohol copolymer as active ingredients As an essential constituent layer.

The body of the oxygen-absorbing multilayer tube forms a space for holding the contents in the oxygen-absorbing multilayer tube, and is connected to the mouth and neck having the pouring outlet for the contents, while its tail is It is formed in a fishtail shape.
The body is composed of an inner surface resin layer, an oxygen-absorbing gas barrier resin layer containing a conjugated diene polymer cyclized product and an ethylene-vinyl alcohol copolymer as active ingredients, and a surface resin layer in this order. It has a multilayer structure inside the tube.

  The inner surface resin layer melts by heat and adheres to each other (heat-sealed), thereby forming a space in the oxygen-absorbing multilayer tube that is cut off from the outside of the tube, and oxygen-absorbing. This is a layer that allows oxygen to permeate and absorb into the oxygen absorbent layer while preventing direct contact between the oxygen absorbent layer and the object to be contained inside the multilayer tube.

  A heat-sealable resin is used to form the inner surface resin layer. Specific examples of heat-sealable resins include homopolymers of α-olefins such as ethylene and propylene, such as low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, metallocene polyethylene, polypropylene, and polymethyl. Penten, polybutene; copolymer of ethylene and α-olefin, for example, ethylene-propylene copolymer; copolymer of α-olefin and vinyl acetate, acrylic acid ester, methacrylic acid ester, etc. mainly composed of α-olefin Polymer, for example, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer; polyethylene or polypropylene Such as olefin resin Acid-modified olefin resin modified with unsaturated carboxylic acids such as phosphoric acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid; Na ion and Zn ion act on copolymer of ethylene and methacrylic acid Ionomer resins made of these; mixtures thereof; and the like.

  Heat-sealable resin, if necessary, antioxidant; tackifier (hydrogenated petroleum resin, hydrogenated terpene resin, castor oil derivative, sorbitan higher fatty acid ester, low molecular weight polybutene, etc.); antistatic agent; filling Agents; plasticizers (phthalate esters, glycol esters, etc.); surfactants; leveling agents; heat stabilizers; weathering stabilizers; ultraviolet absorbers; light stabilizers; dehydrating agents; pot life extenders (acetylacetone, methanol, Methyl orthoacetate, etc.); repellency improver; antiblocking agent; antifogging agent; lubricant; reinforcing agent; flame retardant; coupling agent; foaming agent;

  The film thickness of the inner resin layer is preferably 20 to 200 μm, more preferably 30 to 150 μm, regardless of the number of layers of the oxygen-absorbing multilayer tube. When the film thickness of the inner surface resin layer is within this range, the oxygen permeability becomes appropriate, and oxygen inside the oxygen-absorbing multilayer tube is favorably absorbed by the conjugated diene polymer cyclized product.

In the present invention, the oxygen-absorbing gas barrier resin layer contains a conjugated diene polymer cyclized product and an ethylene-vinyl alcohol copolymer as active ingredients.
The conjugated diene polymer cyclized product, which is one of the active components of the oxygen-absorbing gas barrier resin layer, is obtained by cyclizing the conjugated diene polymer in the presence of an acid catalyst.
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 p-tert. 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) a (Meth) acrylic acid esters such as methyl crylate 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 conjugated diene monomer homopolymers and copolymers include natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), butadiene-isoprene copolymer rubber (BIR), and the like. Can be mentioned. Among these, polyisoprene rubber and polybutadiene rubber are preferable, and polyisoprene rubber is more preferable.

Specific examples of the copolymer of a conjugated diene monomer and a monomer copolymerizable therewith include styrene-isoprene rubber (SIR), styrene-butadiene rubber (SBR), isoprene-isobutylene copolymer rubber ( IIR), ethylene-propylene-diene copolymer rubber (EPDM) and the like.
Among these, a block copolymer having an aromatic vinyl polymer block having a weight average molecular weight of 1,000 to 500,000 and at least one conjugated diene polymer block is preferable.

The content of the conjugated diene monomer unit in the conjugated diene polymer is appropriately selected within a range not impairing the effects of the present invention, but is usually 40 mol% or more, preferably 60 mol% or more, more preferably 80 mol. % Or more. 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.
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 or the like as a catalyst component. Performed by polymerization.

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, ethylaluminum dichloride, 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 the conjugated diene polymer in a hydrocarbon solvent.
The hydrocarbon solvent is not particularly limited as long as it does not inhibit the cyclization reaction. Specific examples include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; alicyclic rings such as cyclopentane and cyclohexane. Group hydrocarbons; 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 the same. 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 7 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.

The unsaturated bond reduction rate of the conjugated diene polymer cyclized product is preferably 10% or more, more preferably 40 to 75%, still more preferably 45 to 65%. 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.
If the unsaturated bond reduction rate of the conjugated diene polymer cyclized product is too low, the glass transition temperature is lowered and the adhesive strength is lowered. On the other hand, a conjugated diene polymer cyclized product having an excessively low unsaturated bond reduction rate is difficult to produce, and only a brittle product can be obtained.

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 weight average molecular weight of the conjugated diene polymer cyclized product is a standard polystyrene conversion value measured by gel permeation chromatography, and is usually 1,000 to 1,000,000, preferably 10,000 to 700,000, More preferably, it is 30,000-500,000. 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 small, 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 large, the solution viscosity at the time of the cyclization reaction is increased, and it becomes difficult to handle and the workability at the time of molding may be lowered.

  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. If the amount of gel is large, processability may be reduced during molding, and it may be difficult to obtain a smooth film.

  In the present invention, the conjugated diene polymer cyclized product may be used alone or in combination of two or more different monomer compositions, molecular weights, unsaturated bond reduction rates, gel amounts and the like. .

In the present invention, an antioxidant can be added to the conjugated diene polymer cyclized product in order to ensure the stability during processing of the conjugated diene polymer cyclized product. The amount of the antioxidant is usually 3,000 ppm or less, preferably 10 to 2,000 ppm, more preferably 50 to 1,500 ppm based on the weight of the conjugated diene polymer cyclized product.
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 in consideration of the stability during processing.

  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. An amine light stabilizer (HALS) may be added. These antioxidants can also be used in combination of two or more. In particular, the combined use of a hindered phenol antioxidant and a phosphorus antioxidant is preferred.

  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.

In addition, a lactone antioxidant which is a reaction product of 5,7-di-t-butyl-3- (3,4-dimethylphenyl) -3H-benzofuran-2-one and o-xylene is used in combination. May be.
Examples of the amine light stabilizer (HALS) include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate.

  In addition to the cyclized conjugated diene polymer, various compounds that are usually added may be blended as necessary. 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, etc.); plasticizers (Phthalic acid ester, glycol ester, etc.); surfactant; leveling agent; ultraviolet absorber; light stabilizer; dehydrating agent; pot life extender (acetylacetone, methanol, methyl orthoacetate, etc.); repellent improver; be able to.

In the present invention, the ethylene-vinyl alcohol copolymer, which is another essential component of the oxygen-absorbing gas barrier resin layer, is a copolymer having ethylene and vinyl alcohol as main structural units in terms of structure. Actually, it can be obtained by saponifying a copolymer of ethylene and a fatty acid vinyl ester with an alkali catalyst or the like.
Typical examples of the fatty acid vinyl ester copolymerized with ethylene include vinyl acetate, but in addition, vinyl fatty acid propionate and vinyl pivalate may be used. The ethylene-vinyl alcohol copolymer used in the present invention is not particularly limited by the saponification method.

In the ethylene-vinyl alcohol copolymer used in the present invention, the ethylene content is preferably 15 mol% or more, more preferably 30 mol% or more, and particularly preferably 35 to 45 mol%. preferable. The ethylene content can be determined by a nuclear magnetic resonance (NMR) method.
When the ethylene content is within this range, the compatibility with the conjugated diene polymer cyclized product is improved, and the resulting resin composition comprising the conjugated diene polymer cyclized product and the ethylene-vinyl alcohol copolymer. The gas barrier property of the product is excellent.
An ethylene-vinyl alcohol copolymer may be used individually by 1 type, or may use 2 or more types together.
The ethylene content in the ethylene-vinyl alcohol copolymer mixture when two or more kinds having different ethylene contents are used in combination can be determined from the blending weight ratio.

Degree of saponification of vinyl ester part of ethylene-vinyl alcohol copolymer (monomer unit part having vinyl alcohol structure relative to the sum of monomer unit part having vinyl alcohol structure and monomer unit part having vinyl ester structure) Is preferably 90 mol% or more, more preferably 95 mol% or more, and particularly preferably 97% or more.
The saponification degree can be determined by a nuclear magnetic resonance (NMR) method.
When the saponification degree of an ethylene-vinyl alcohol copolymer is within the above range, a gas barrier of a resin composition comprising a conjugated diene polymer cyclized product and an ethylene-vinyl alcohol copolymer obtained by using the saponification degree Excellent in properties. Further, the ethylene-vinyl alcohol copolymer has good thermal stability, and no foreign matter such as gels or so-called bumps are generated in the molded product of the resin composition obtained by using the ethylene-vinyl alcohol copolymer.
The saponification degree in the ethylene-vinyl alcohol copolymer mixture when two or more kinds having different saponification degrees are used together is determined from the blending weight ratio.

The ethylene-vinyl alcohol copolymer used in the present invention has an oxygen transmission rate of 0.2 to 2 cc · cm when measured under the conditions of 20 ° C. and 65% relative humidity on a film having a thickness of 20 μm. It is preferably 20 μm / m ² · day · atm. That is, the oxygen volume permeating through a film having a thickness of 20 μm and an area of 1 m ² in one day under a temperature and humidity condition of 1 atm is 0.2 to 2 cc. preferable.

In the oxygen-absorbing gas barrier resin layer of the oxygen-absorbing multilayer tube of the present invention, the weight ratio of the conjugated diene polymer cyclized product to the ethylene-vinyl alcohol copolymer (conjugated diene polymer cyclized product / ethylene-vinyl alcohol copolymer). The coalescence is preferably 50/50 to 5/95, and more preferably 15 / to 40/60.
When the weight ratio of the conjugated diene polymer cyclized product to the ethylene-vinyl alcohol copolymer is within the above range, the resulting oxygen-absorbing gas barrier resin layer has good characteristics.

  The oxygen-absorbing gas barrier resin layer may contain a known oxygen-absorbing component other than the conjugated diene polymer cyclized product as long as the effects of the present invention are not impaired. The amount of the oxygen-absorbing component other than the conjugated diene polymer cyclized product is based on the total amount of the oxygen-absorbing component (the total amount of the oxygen-absorbing component other than the conjugated diene polymer cyclized product and the conjugated diene polymer cyclized product). , Less than 50% by weight, preferably less than 40% by weight, more preferably less than 30% by weight.

In the present invention, the oxygen-absorbing gas barrier resin layer may contain an olefin resin in addition to the conjugated diene polymer cyclized product and the ethylene-vinyl alcohol copolymer. By containing the olefin resin, the miscibility of the conjugated diene polymer cyclized product with the ethylene-vinyl alcohol copolymer and the adhesion with the inner or outer resin layer of the oxygen-absorbing gas barrier resin layer are improved. The
The content of the olefin resin is preferably 10 to 150 parts by weight, more preferably 30 to 100 parts by weight with respect to 100 parts by weight of the conjugated diene polymer cyclized product.

  In the present invention, an olefin resin that can be suitably used for the oxygen-absorbing gas barrier resin layer is an α-olefin homopolymer, a copolymer of two or more α-olefins, or a single unit other than an α-olefin and an α-olefin. Any of the copolymers with the polymer may be used, or those (co) polymers may be modified.

Specific examples of olefin resins include homopolymers or copolymers of α-olefins 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, α-olefin homopolymers such as polypropylene, metallocene polypropylene, polymethylpentene, polybutene; copolymers of ethylene and other α-olefins such as ethylene Propylene random copolymer, ethylene-propylene block copolymer, ethylene-propylene-polybutene-1 copolymer, ethylene-cycloolefin copolymer, etc .; α-olefin and carboxylic acid unsaturated mainly composed of α-olefin Alcohol with alcohol Copolymers and saponified products thereof, such as ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, etc .; α-olefin and α, β-unsaturated carboxylic acid ester or α, β mainly composed of α-olefin -Copolymers with unsaturated carboxylic acids, such as ethylene-α, β-unsaturated carboxylic acid ester copolymers (ethylene-ethyl acrylate copolymers, ethylene-methyl methacrylate copolymers, etc.), ethylene -Α, β-unsaturated carboxylic 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, etc. Acid-modified olefin resins modified with unsaturated carboxylic acids such as acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid; ethylene and methacrylic An ionomer resin obtained by allowing Na ion, Zn ion or the like to act on a copolymer with an acid, etc .; a mixture thereof;
Of these resins, polyethylene, polypropylene, random and block ethylene-propylene copolymers are preferred.

  In the present invention, the oxygen-absorbing gas barrier resin layer may be used in combination with a resin other than the conjugated diene polymer cyclized product, the ethylene-vinyl alcohol copolymer, and the olefin resin. The amount used is not particularly limited as long as the effect of the present invention is not impaired, but is preferably 20% by weight or less based on the total weight of the oxygen-absorbing gas barrier resin layer.

Specific examples of such resins include polyester resins such as polyethylene terephthalate and polybutylene terephthalate; nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, MXD nylon (polymetaxylylene adipamide), and these Polyamide resin such as copolymer; Polyaramid resin; Polycarbonate resin; Polystyrene resin; Polyacetal resin; Fluororesin; Thermoplastic polyurethane such as polyether, adipate ester, caprolactone ester, and polycarbonate ester; polyvinylidene chloride, poly And vinyl halide resins such as vinyl chloride; polyacrylonitrile; mixtures thereof; and the like.
These resins that can be used in combination can be appropriately selected in consideration of desired characteristics such as gas barrier properties, mechanical properties such as strength, toughness, and rigidity, heat resistance, printability, transparency, and adhesiveness. it can. These resins may be used alone or in combination of two or more.

For the resin other than the conjugated diene polymer cyclized product used for the oxygen-absorbing gas barrier resin layer, heat stabilizer, ultraviolet absorber, antioxidant, colorant, pigment, neutralizer, phthalate ester, glycol ester, etc. Plasticizers; Fillers; Surfactants; 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 polybutene); pot life extender (acetylacetone, methanol, methyl orthoacetate, etc.); repellent improver; other resin (poly α-olefin, etc.);
Add antiblocking agents, antifogging agents, heat stabilizers, weathering stabilizers, lubricants, antistatic agents, reinforcing agents, flame retardants, coupling agents, foaming agents, release agents, etc. as necessary. be able to.

As the antioxidant, those which can be added to the conjugated diene polymer cyclized product can be similarly used.
Examples of the anti-blocking agent include silica, calcium carbonate, talc, zeolite, starch and the like. The anti-blocking agent may be kneaded into the resin or adhered to the surface of the resin.
Antifogging agents include higher fatty acid glycerides such as diglycerin monolaurate, diglycerin monopalmitate, diglycerin monooleate, diglycerin dilaurate, triglycerin monooleate; polyethylene glycol oleate, polyethylene glycol laurate, polyethylene And polyethylene glycol higher fatty acid esters such as glycol palmitate and polyethylene glycol stearate: polyoxyethylene higher fatty acid alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether;

Examples of the lubricant include stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, ethylene bis stearic acid amide, ethylene bis oleic acid amide and the like; higher fatty acid amides; waxes, and the like.
Examples of the antistatic agent include glycerin esters, sorbitan esters, and polyethylene glycol esters of higher fatty acids.
Examples of the reinforcing agent include metal fibers, glass fibers, and carbon fibers.
Examples of the flame retardant include phosphoric acid esters, halogenated phosphoric acid esters, and halides.
Examples of coupling agents include silane-based, titanate-based, chromium-based, and aluminum-based coupling agents.
Examples of colorants and pigments include various azo pigments such as phthalocyanine, indigo, quinacridone, and metal complex salts; basic and acidic water-soluble dyes; azo, anthraquinone, and perylene oil-soluble dyes; titanium oxide Examples thereof include metal oxides such as those based on iron oxide, iron oxide, and complex oxide; and other inorganic pigments such as chromate, sulfide, silicate, and carbonate.
Examples of the foaming agent include methylene chloride, butane, azobisisobutyronitrile, and the like.
Examples of the mold release agent include polyethylene wax, silicone oil, long chain carboxylic acid, and long chain carboxylic acid metal salt.

  The film thickness of the oxygen-absorbing gas barrier resin layer is preferably in the range of 3 to 100 μm, more preferably in the range of 5 to 80 μm, regardless of the constituent materials. When the thickness of the oxygen-absorbing gas barrier resin layer is within this range, good oxygen-absorbing properties and gas barrier properties can be obtained, and from the viewpoint of container properties such as economy and material flexibility and flexibility. Is also preferable.

The oxygen-absorbing multilayer tube of the present invention may have a deodorant layer containing a deodorizing component in addition to the oxygen-absorbing gas barrier resin layer. The position where the deodorizing layer is provided is not particularly limited, but is preferably between the oxygen-absorbing gas barrier layer and the outer resin layer.
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.

The adsorbent may be an organic adsorbent or an inorganic adsorbent, but an inorganic adsorbent is preferred from the viewpoint of heat resistance.
Specific examples of the organic adsorbent include soybean powder, polyester resin, acrylic resin and the like.
Specific examples of the inorganic adsorbent include natural zeolite, synthetic zeolite, silica gel, activated carbon, impregnated activated carbon, activated clay, activated aluminum oxide, clay, diatomaceous earth, kaolin, talc, bentonite, magnesium oxide, iron oxide, aluminum hydroxide, water Examples thereof include magnesium oxide, iron hydroxide, magnesium silicate, aluminum silicate, synthetic hydrotalcite, silicon dioxide, sepiolite, and viscosity minerals such as mica.

  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 such as sodium hydroxide, potassium hydroxide, magnesium hydroxide and calcium hydroxide; other hydroxides such as iron hydroxide; sodium carbonate, carbonate Contains inorganic basic compounds such as carbonates containing deodorizing components such as potassium, calcium carbonate and magnesium carbonate; alkali metal hydrogen carbonates such as sodium bicarbonate and potassium bicarbonate; ammonia and amino groups or imino groups Organic basic compounds such as compounds (collectively referred to as “amino group-containing compounds”); compounds containing amide groups or imide groups (collectively referred to as “amide group-containing compounds”); urea-bonded compounds; Can be mentioned.

The amino group-containing compound may be a monovalent amine or a polyvalent amine, may be linear or cyclic, and may have a functional group such as a hydroxyl group or a carboxyl group. The amino group may be primary, secondary or tertiary. Specific examples of the amino group-containing compound include monovalent amines such as isopropylamine, butylamine, dimethylamine, diethylamine, and allylamine; ethylenediamine, propylenediamine (1,3-diaminopropane), 1,2-diaminopropane, and tetramethylenediamine. , Hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, etc .; amino acids such as glycine, alanine, sarcosine, glutamic acid, aminobenzoic acid; hydroxylamine, methanolamine, ethanolamine, 2-diethylaminoethanol Hydroxyl-containing amines such as 2-dimethylaminoethanol; halogen-containing amines such as chloramine; ethyleneimine, morpholine, piperidine, 2-amino-4,5-di Mention may be made of other dicyandiamide, guanidine carbonate and the like; Ano imidazole, proline, hydroxyproline, melamine, cyclic amines guanine like.
Examples of the amide group-containing compound include 2-acrylamido-2-methylpropanesulfonic acid, phthalimide, succinimide, hydantoin, barbituric acid, isocyanuric acid, α-amino-ε-caprolactam and the like.
Examples of the urea bond-containing compound include urea, thiourea, ethylene urea, acetyl urea, guanyl urea, azodicarbonamide and the like.

For the purposes of the present invention, basic compounds including amino group-containing compounds are preferably those having low volatility. Accordingly, the amino group-containing compound is also preferably a compound having a structure in which an amino group is introduced into various nonvolatile compounds. One specific example thereof is a silane coupling agent having an amino group.
As a silane coupling agent which has an amino group, what is represented by following formula (1) is preferable.
_{^{H 2 N-X-SiR 1}} n (OR 2) 3-n (1)
(In the formula, n represents 0, 1 or 2. X represents a linear or branched divalent hydrocarbon group having 1 to 5 carbon atoms, specifically, —CH ₂ —, —CH _{2. CH 2 -, - CH 2 CH} 2 CH 2 -, - CH 2 CH (CH 3) -, - CH 2 CH 2 CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH 2 CH ₂ CH (CH ₃ ) —, —CH ₂ C (CH ₃ ) ₂ —, —CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ CH ₂ —, —CH ₂ CH _{2 CH (CH 3) CH 2} -, - CH 2 CH 2 CH 2 CH (CH 3) -, - CH 2 C (CH 3) 2 CH 2 -, - CH 2 CH 2 C (CH 3) 2 - and the like .R ¹ is represents an alkyl group having 1 to 3 carbon atoms, _{specifically, -CH 3, -CH 2 CH 3} , CH ₂ CH ₂ CH _3, a -CH _{(CH 3)} CH 3, etc. .R ² represents an alkyl group having 1 to 3 carbon atoms, _{specifically, -CH 3, -CH 2 CH 3} , -CH ₂ CH ₂ CH ₃ , —CH (CH ₃ ) CH _3, etc.)

  Preferred examples of the silane coupling agent having an amino group are γ-aminopropyltriethoxysilane, γ-aminopropyldimethylethoxysilane, γ-aminopropylmethyldiethoxysilane, and γ-aminopropyltrimethoxysilane. From the viewpoint of properties, γ-aminopropyltriethoxysilane is preferable.

In the present invention, as the deodorizing component, a deodorizing agent supported on an adsorbent, in particular, a basic compound supported on the adsorbing agent, particularly an amino group-containing compound supported on the adsorbing agent can be suitably used.
As a specific example thereof, a polyamine represented by the general formula H ₂ N (C ₂ H ₄ NH) _n C ₂ H ₄ NH ₂ (where n is an integer of 0 or more) is supported on aluminum hydroxide. Amine-supported silica in which an amine-supported aluminum hydroxide (commercially available under the trade name “Kesmon NS-231” manufactured by Toagosei Co., Ltd.), an amino group-containing silane coupling agent, and the like is bonded to the surface of the silica. And amine-supporting porous silica obtained by binding an amino group-containing silane coupling agent or the like to the surface of the porous silica.
The amine-supported aluminum silicate or amine-supported silica preferably has a water content of 0.01 to 5% by weight and a supported compound amount of 0.02 to 10 mmol / g.

  Although the manufacturing method of the said amine carrying | support aluminum silicate is not specifically limited, A wet method can be shown as an example. In this method, an aluminum silicate carrying a polyamine compound uniformly can be obtained by diluting the polyamine compound with water or the like and mixing it with aluminum silicate. Usually, an excess amount of polyamine compound is mixed with aluminum silicate, and after mixing, the aluminum silicate is washed with pure water to remove excess polyamine compound adhering to the surface, and then dried at 50 to 120 ° C. .

The surface treatment method of silica or porous silica with a silane coupling agent containing an amino group is not particularly limited, and known methods such as a dry method, a slurry method, a pretreatment method such as a spray method, an integral blend method, etc. This method can be used. The pretreatment method is preferable in that the silica surface can be uniformly treated.
The amount of the silane coupling agent having an amino group supported on silica or porous silica is preferably 0.1 to 1 mmol, and preferably 0.3 to 0.8 mmol, with respect to 1 g of the carrier. More preferred.

In the oxygen-absorbing multilayer tube of the present invention, the deodorant layer may be composed of only the deodorizing component, but is preferably a deodorizing resin layer in which the deodorizing component is dispersed in the resin.
At this time, it is preferable that the quantity of the deodorizing component in a deodorizing resin layer is 0.1 to 5 weight%.
Moreover, in order to ensure uniform dispersibility, the average dispersed particle size of the deodorizing component is preferably 0.01 to 50 μm, more preferably 0.01 to 20 μm, and particularly preferably 0.1 to 5 μm.

  The resin used in the deodorant layer is not particularly limited, but is preferably a thermoplastic resin, and the thermoplastic resin may be the one described above as the thermoplastic resin in the oxygen-absorbing gas barrier resin layer. it can. Of the thermoplastic resins, olefin resins are preferred. Preferable olefin resins include those that can be preferably used in the oxygen-absorbing gas barrier resin layer.

In the oxygen-absorbing multilayer tube of the present invention, a surface resin layer is provided outside the oxygen-absorbing gas barrier resin layer.
The resin used for forming the surface resin layer is a cylindrical body obtained by rolling a multilayer laminate having the structure of inner surface resin layer-oxygen-absorbing gas barrier resin layer-surface resin layer, and welding the overlapping end portions. Because of the necessity of forming the part, a heat-sealable resin that can be melted by heating and fused to each other and can be extruded is preferable.
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.
Specific examples of the resin used for forming the surface resin layer include those exemplified as those used for forming the inner surface resin layer.

  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.

In the oxygen-absorbing multilayer tube of the present invention, a protective layer can be formed outside the surface resin 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 the multilayer tube of the present invention, the inner surface resin layer, the oxygen-absorbing gas barrier resin layer, the deodorant layer, the surface resin layer and the protective layer may all be a single layer or a plurality of layers. Each may be the same or different.

  In the oxygen-absorbing multilayer tube of the present invention, an adhesive layer made of an adhesive resin may be interposed between each layer such as the inner surface resin layer, the oxygen-absorbing gas barrier resin layer, the deodorant layer, the surface resin layer, and the protective layer. Is possible. 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 resins include, for example, homopolymers or copolymers of α-olefins such as low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, and polypropylene; ethylene-vinyl acetate. Copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer; α-olefin (co) heavy such as polyethylene and polypropylene Acid-modified olefin resin modified with unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, etc .; ionomer in which Na ion, Zn ion, etc. are allowed to act on a copolymer of ethylene and methacrylic acid Resin; mixtures thereof; and the like.

The oxygen-absorbing multilayer tube of the present invention has a mouth-and-neck portion connected to the trunk portion for pouring the contents.
From the inside to the outside of the mouth and neck, the inner surface resin layer, the conjugated diene polymer cyclized product, and the oxygen-absorbing gas barrier resin layer and the surface resin layer containing the ethylene-vinyl alcohol copolymer as essential components are essential components. It is laminated as a layer.
The material used for the structure of each layer can be the same material as that used for the structure of the body.
The mouth / neck portion may be one in which an aluminum cup is inserted and fixed on the innermost side.

The production method of the oxygen-absorbing multilayer tube of the present invention may be a conventionally known method, for example, an extrusion laminate, a co-extrusion laminate, a dry laminate, or the like, and an inner surface resin layer, a conjugated diene polymer cyclized product, and ethylene. -After producing a multilayer laminate having an oxygen-absorbing gas barrier resin layer and a surface resin layer as essential constituents, each comprising a vinyl alcohol copolymer as an active ingredient, this is rolled up, and both ends of the multilayer laminate are produced. The surface of the surface resin layer that is the outer layer of the part is overlapped with the surface of the inner surface resin layer that is the innermost layer, and the overlap end is fused to form a cylindrical body, and then the cylindrical body The shoulder part that forms the tube container is formed in the upper part of one opening of the part by a conventional method, and the mouth and neck part manufactured by injection molding is joined thereto, and the cap is attached to the mouth and neck part. It can be.
Also, a method of joining an oxygen-absorbing multilayer tube having an oxygen-absorbing gas barrier resin layer formed by coextrusion as an intermediate layer and a mouth-and-neck portion formed by injection, or an oxygen-absorbing gas barrier resin by direct multilayer blowing It can be produced by a conventionally known multilayer tube production method such as a method of forming an oxygen-absorbing multilayer tube having a layer as an intermediate layer.

  The oxygen-absorbing multilayer tube of the present invention includes, for example, seasonings such as mayonnaise, miso, mustard, wasabi, ginger, garlic and other seasonings, jam, cream, butter, margarine, chocolate paste and other pasty food Various foods such as pharmaceuticals; cosmetics such as cosmetic creams, hair dyes and soaps; hygiene materials such as toothpastes; chemicals such as adhesives;

Hereinafter, the present invention will be described more specifically with reference to production examples, examples and comparative 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 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 after oxygen absorption]
The oxygen-absorbing multilayer tube was cut into a size of 100 mm × 400 mm, and both ends were heat-sealed using a heat sealer to prepare a bag. After completely removing the air inside, 100 cc of air (oxygen concentration 20.7%) was sealed again and allowed to stand at 25 ° C. for 14 days, and then the oxygen concentration inside the bag was measured with an oximeter (USA Ceratech). Measurement is performed using a product name “Food Checker HS-750”).

(Production Example 1: Production of styrene-isoprene block polymer cyclized product AK)
A hexane solution containing 233 parts of cyclohexane, 25 parts of styrene, and 0.113 parts of n-butyllithium (added with a hexane solution having a concentration of 1.56 mol / liter) is charged into an autoclave equipped with a stirrer, and the internal temperature is set to 60 ° C. The temperature was raised and polymerization was carried out for 30 minutes. The polymerization conversion of styrene was almost 100%. Subsequently, 75 parts of isoprene were continuously added over 60 minutes while controlling the internal temperature not to exceed 75 ° C. After completion of the addition, the mixture was further reacted at 70 ° C. for 1 hour. The polymerization conversion rate at this point was almost 100%.
To the polymerization solution thus obtained, 0.016 part of a sodium salt of β-naphthalenesulfonic acid-formalin condensate was added as a 1% aqueous solution to stop the polymerization reaction, and from the polystyrene block and the polyisoprene block. A styrene-isoprene block polymer A having a diblock structure was obtained. A part of this was sampled and the weight average molecular weight was measured.
To the solution of the block copolymer A, 1.01 part of p-toluenesulfonic acid having a water content of 150 ppm or less was added as a 15% toluene solution, and a cyclization reaction was performed at 75 ° C. for 6 hours. Thereafter, a 25% aqueous sodium carbonate solution containing 0.391 parts of sodium carbonate was added to stop the cyclization 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 diameter of 2 μm.

  To the solution of the obtained styrene-isoprene block polymer cyclized product AK, the hindered phenolic antioxidant n-octadecyl-3- (3,5-di-t is added to the styrene-isoprene block polymer cyclized product AK. -Butyl-4-hydroxyphenyl) propionate (Ciba Specialty Chemicals, trade name “Irganox 1076”) 300 ppm and phosphorus antioxidant 2,2′-methylenebis (4,6-di-t-butyl) After adding 600 ppm of phenyl) octyl phosphite (manufactured by Asahi Denka Kogyo Co., Ltd., trade name “Adeka Stub HP-10”), the cyclohexane in the solution was distilled off, and further vacuum drying was performed to remove toluene, A styrene-isoprene block polymer cyclized product AK was obtained. The resulting styrene-isoprene block polymer cyclized product AK had an unsaturated bond reduction rate of 50% and a weight average molecular weight of 73,000.

  Using the obtained styrene-isoprene block polymer cyclized product AK using a short shaft kneading extruder (Ikegai Seisakusho, Ikekai short shaft kneading extruder (40φ, L / D = 25, die φ = 3 mm, one hole)) The temperature of cylinder 1 is 140 ° C., the temperature of cylinder 2 is 150 ° C., the temperature of cylinder 3 is 160 ° C., the temperature of cylinder 4 is 170 ° C., the temperature of the die is 170 ° C., and the kneading conditions are 25 rpm. Then, pelletization was performed to obtain a pellet ak of the styrene-isoprene block polymer cyclized product AK.

(Production Example 2: Production of cyclized polyisoprene BK / polyethylene blend)
A polyisoprene (cis-1,4 structural unit 73%, trans-1,4 structural unit 22%, trans 1,4 structural unit 22%, 3%, and pressure resistant reactor equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube. , 4 structural unit 5%, weight average molecular weight 154,000) together with 700 parts of cyclohexane was charged, and the inside of the reactor was purged with nitrogen. The content was heated to 75 ° C., and polyisoprene was completely dissolved in cyclohexane with stirring. Then, 2.4 parts of p-toluenesulfonic acid having a water content of 150 ppm or less was added as a 25% toluene solution, and 80 ° C. The cyclization reaction was performed as follows. After continuing the reaction for 7.5 hours, 3.68 parts of 25% aqueous sodium carbonate solution 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 polyisoprene cyclized product BK solution.

To the resulting polyisoprene cyclized product BK solution, 400 ppm of the hindered phenolic antioxidant n-octadecyl-3- (3,5-di-t-butyl-4-hydroxy) with respect to 100 parts of the polyisoprene cyclized product BK. Phenyl) propionate (Ciba Specialty Chemicals, trade name “Irganox 1076”) and 800 ppm phosphorus antioxidant 2,2′-methylenebis (4,6-di-t-butylphenyl) octylphos 105 parts of polyethylene pellets (melt flow rate (MFR) = 4.0 (g / 10 min, 190) manufactured by Asahi Denka Kogyo Co., Ltd., trade name “ADK STAB HP-10”) and polyisoprene cyclized product BK 100 parts ℃, load 2.16kg), made by Idemitsu Kosan Co., Ltd., trade name "moretech 0438") After the addition, a part of cyclohexane in the solution was distilled off, and further vacuum drying was performed to remove cyclohexane and toluene to obtain a solid polyisoprene cyclized product BK / polyethylene blend. Separately, after adding only the two kinds of antioxidants to the polyisoprene cyclized product BK solution, a part of cyclohexane in the solution is distilled off, and further vacuum drying is performed to remove cyclohexane and toluene. A solid polyisoprene cyclized product BK was obtained. The polyisoprene cyclized product BK had a weight average molecular weight of 138,000 and an unsaturated bond reduction rate of 46.5%.
The solid polyisoprene cyclized product BK / polyethylene blend was kneaded under the same kneading conditions as in Production Example 1 and pelletized to obtain a polyisoprene cyclized BK / polyethylene blend pellet bk / e.

(Production Example 3) (Production of oxygen-absorbing gas barrier resin pellets)
Ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., trade name “EVAL E105B”, oxygen transmission rate 1.3 cc · 20 μm / m ² · day · atm (@ 20 ° C.), moisture permeability 19 g / m ² · 24 hr, MFR = 55 (g / 10 min, @ 190 ° C., load 2.16 kg)) 60 parts of pellets (ev1) and 40 parts of pellets ak obtained in Production Example 1 were mixed into a short shaft kneading extruder (Ikegai short shaft kneading extruder). (40φ, L / D = 25, die φ = 3mm, one hole)), the temperature of cylinder 1: 165 ° C, the temperature of cylinder 2: 175 ° C, the temperature of cylinder 3: 185 ° C, The mixture was kneaded under the kneading conditions of temperature: 190 ° C., die temperature: 190 ° C., rotation speed: 25 rpm, and pelletized to obtain oxygen-absorbing gas barrier resin pellets ak / ev1.

(Production Example 4) (Production of oxygen-absorbing gas barrier resin pellets)
Production Example 3 except that the pellet bk / e of the polyisoprene cyclized product BK / polyethylene blend obtained in Production Example 2 was used instead of the pellet ak of the styrene-isoprene block polymer cyclized product AK obtained in Production Example 1. In the same manner as above, oxygen-absorbing gas barrier resin pellets bk / e / ev1 were obtained.

(Production Example 5: Production of iron-based oxygen scavenger-containing resin composition pellets)
Using a twin screw extruder (trade name “TEM-35B”, manufactured by Toshiba Machine Co., Ltd.) with a strand die attached to the outlet portion, 3 parts by weight of calcium chloride per 100 parts by weight of reduced iron powder with an average particle size of 30 μm A granular oxygen scavenger coated with 40 parts by weight and 60 parts by weight of a low density polyethylene resin (trade name “LC-600A”, manufactured by Nippon Olefin Co., Ltd.) at 185 ° C. while performing high vacuum venting at a screw rotation speed of 100 ppm. Extruded into a strand shape to produce an iron-based oxygen scavenger-containing resin composition pellet c.

(Production Example 6) (Production of sheet for producing oxygen-absorbing multilayer tube comprising inner surface resin-low density polyethylene resin-oxygen absorbing gas barrier resin-low density polyethylene resin-outer surface resin)
The oxygen-absorbing gas barrier resin pellet ak / ev1 produced in Production Example 3 is used as an intermediate layer, and a low-density polyethylene resin (trade name “LC-600A” manufactured by Nippon Polyolefin Co., Ltd.) is used as an outer layer. And a biaxial stretching test apparatus (both manufactured by Toyo Seiki Seisakusho Co., Ltd.) and extrusion-molded, and two types and three layers (low density polyethylene resin layer- (styrene) having an intermediate layer thickness of 20 μm and both outer layers thickness of 50 μm. A multilayer sheet composed of -cyclized product of isoprene block polymer / (ethylene-vinyl alcohol copolymer) blend layer-low density polyethylene resin layer] was obtained.
This multi-layer sheet and two polyethylene sheets having a thickness of 150 μm (density = 0.92, manufactured by Nihon Unicar Co., Ltd., trade name “NUC G5371”) were combined with a hot roll laminator (manufactured by Gmp Co. Ltd, trade name “ EXCELAM II 355Q "), and laminator adhesion, polyethylene resin layer (inner surface resin layer) -low density polyethylene resin layer- (styrene-isoprene block polymer cyclized product) / (ethylene-vinyl alcohol copolymer) blend An oxygen-absorbing multilayer tube-producing sheet S1 having a five-layer structure of physical layer (oxygen-absorbing gas barrier resin layer) -low density polyethylene resin layer-polyethylene resin layer (surface resin layer) was obtained.

(Production Example 7) (Production of sheet for producing oxygen-absorbing multilayer tube comprising inner surface resin-low density polyethylene resin-oxygen absorbing gas barrier resin-low density polyethylene resin-outer surface resin)
Instead of the oxygen-absorbing gas barrier resin pellets ak / ev1 produced in Production Example 3, the oxygen-absorbing gas barrier resin pellets bk / e / ev1 obtained in Production Example 4 were used. Polyethylene resin layer (inner surface resin layer) -low density polyethylene resin layer- (polyisoprene cyclized product / polyethylene blend product) / (ethylene-vinyl alcohol copolymer) blend product layer (oxygen-absorbing gas barrier resin layer)- A five-layer oxygen-absorbing multilayer tube manufacturing sheet S2 having a structure of a low density polyethylene resin layer-polyethylene resin layer (surface resin layer) was obtained.

(Production Example 8) (Production of sheet for producing oxygen-absorbing multilayer tube comprising inner surface resin-oxygen absorbing resin-low density polyethylene resin-gas barrier resin-outer surface resin)
The iron-based oxygen scavenger-containing resin composition pellet c produced in Production Example 5 is used as an intermediate layer, and a low-density polyethylene resin (trade name “LC-600A” manufactured by Nippon Polyolefin Co., Ltd.) is used as an outer layer. A die and a biaxial stretching test device (both manufactured by Toyo Seiki Seisakusho Co., Ltd.) were connected and extruded, and two types and three layers (low density polyethylene resin layer-reduced) with an intermediate layer thickness of 20 μm and both outer layers thickness of 50 μm An oxygen-absorbing multilayer sheet comprising an iron oxygen scavenger / low density polyethylene resin blend layer-low density polyethylene resin layer) was obtained.
This oxygen-absorbing multilayer sheet, a 12 μm thick ethylene-vinyl alcohol copolymer film (Kuraray Trading Co., Ltd., trade name “Eval EF-XL”) and a 150 μm thick polyethylene sheet (density = 0.92, Japan) A low-density polyethylene resin layer (inner surface) was bonded to a laminator using a hot roll laminator (Gmp Co. Ltd, product name “EXCELAM II 355Q”) manufactured by Unicar Co., Ltd. Resin layer)-(reduced iron oxygen absorber / low density polyethylene resin) blend layer-low density polyethylene resin layer- (ethylene-vinyl alcohol copolymer) film layer-polyethylene resin layer (surface resin layer) An oxygen-absorbing multilayer tube manufacturing sheet S3 having a configuration was obtained.

Example 1
Using the oxygen-absorbing multilayer tube manufacturing sheet S1, a laminated sheet constituting a laminated tube container is punched to produce a blank plate, and then the blank plate is placed so that the inner resin layer is on the inside. The cylindrical body that is rolled up and heat-sealed at 215 ° C. for 3 seconds under a heat welding condition of 3 Kg / cm 2 to form a body portion of a laminated tube having a diameter of 35 mm and a height of 160 mm. Manufactured.
Next, this cylindrical body is attached to a mandrel for shaping a tube container, and a high-density polyethylene composition comprising 98 parts of high-density polyethylene and 2 parts of milky white pigment (titanium white) is used. A head composed of a continuous narrow neck and neck is formed on one end of the cylindrical body by a compression molding method at a resin temperature of 245 ° C. to produce an oxygen-absorbing multilayer tube t1 according to the present invention. did.
After the inside of the oxygen-absorbing multilayer tube t1 was replaced with air having an oxygen concentration of 20.7%, 100 cc of air having an oxygen concentration of 20.7% was sealed, and an aluminum cap was spirally wound at 14 ° C. at 14 ° C. Stored for days. Thereafter, the oxygen concentration in the tube was measured. The results are shown in Table 1.

(Example 2)
An oxygen absorbing multilayer tube t2 was obtained in the same manner as in Example 1 except that the oxygen absorbing multilayer tube manufacturing sheet S2 was used instead of the oxygen absorbing multilayer tube manufacturing sheet S1. Evaluation similar to Example 1 was performed about this tube. The results are shown in Table 1.

(Comparative Example 1)
An oxygen-absorbing multilayer tube t3 was obtained in the same manner as in Example 1 except that the oxygen-absorbing multilayer tube manufacturing sheet S3 was used instead of the oxygen-absorbing multilayer tube manufacturing sheet S1. Evaluation similar to Example 1 was performed about this tube. The results are shown in Table 1.

From the results of Table 1, the oxygen-absorbing multilayer tube of the present invention having an oxygen-absorbing gas barrier resin layer containing conjugated diene polymer cyclized product and ethylene-vinyl alcohol copolymer as active ingredients is excellent in oxygen absorption. (Examples 1 and 2).
In contrast, a reduced iron oxygen absorber / low density polyethylene resin blend layer using a reduced iron-containing oxygen absorbing component as an oxygen absorbing component, and a gas barrier layer made of an ethylene-vinyl alcohol copolymer film, It turns out that the oxygen absorptive multilayer tube which has is inferior to oxygen absorptivity (comparative example 1).

Claims (6)

  A tube comprising a mouth / neck portion having a spout for contents and a body portion connected to the mouth / neck portion and having its tail end shaped into a fishtail shape, at least the body portion being directed from the inside to the outside Oxygen comprising an inner surface resin layer, a conjugated diene polymer cyclized product, and an ethylene-vinyl alcohol copolymer, which are laminated in the following order, as an essential component, an oxygen-absorbing gas barrier resin layer and a surface resin layer. Absorbent multilayer tube.   An inner surface resin layer in which the mouth and neck are laminated in the following order from the inner side to the outer side, a conjugated diene polymer cyclized product, and an oxygen-absorbing gas barrier resin layer and a surface resin containing an ethylene-vinyl alcohol copolymer as active ingredients The oxygen-absorbing multilayer tube according to claim 1, comprising a layer as an essential constituent layer.   The oxygen-absorbing multilayer tube according to claim 1 or 2, further comprising a deodorant layer.   The oxygen-absorbing multilayer tube according to claim 1 or 2, wherein the conjugated diene polymer cyclized product has an unsaturated bond reduction rate of 10% by weight or more. The oxygen-absorbing multilayer tube according to claim 1 or 2, wherein the ethylene-vinyl alcohol copolymer has an oxygen transmission rate of 0.2 to ² cc · 20 µm / m ² · day · atm (@ 20 ° C). The weight ratio of the conjugated diene polymer cyclized product to the ethylene-vinyl alcohol copolymer (conjugated diene polymer cyclized product / ethylene-vinyl alcohol copolymer) in the oxygen-absorbing gas barrier resin layer is 50/50 to 5/95. The oxygen-absorbing multilayer tube according to claim 1 or 2.