JP2003335932A - Container made of plastic - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container made of a plastic having excellent oxygen absorptivity, gas barrier properties and transparency and flavor retention and keeping quality of contents. <P>SOLUTION: The container made of the plastic is provided with at least one oxygen absorbing resin layer composed of a resin composition prepared by compounding a resin (A) consisting essentially of polyglycolic acid with a hydrocarbon resin (B) containing unsaturated groups and a transition metal catalyst (C). <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic container, and more particularly to a plastic container having excellent storability of contents as a single-layer or multi-layer container. Further, the present invention relates to an environmentally friendly plastic container in which a biodegradable resin is used as a laminated resin so that it can be returned to the natural world at the time of disposal after use.

[0002]

2. Description of the Related Art Conventionally, metal cans, glass bottles, various plastic containers, etc. have been used as packaging containers.
The deterioration of the contents and the deterioration of the flavor due to the oxygen remaining in the container and the oxygen permeating the container wall are problems.

In particular, in metal cans and glass bottles, the oxygen permeation through the container wall is zero, and only oxygen remaining in the container is a problem, whereas in the case of a plastic container, the oxygen permeation through the container wall does not occur. It occurs in an order that cannot be ignored, and is a problem in terms of the storability of the contents.

In order to prevent this, in the plastic container, the container wall has a multi-layer structure, and at least one of them has a resin having oxygen permeation resistance such as ethylene-vinyl alcohol copolymer. There is.

An oxygen scavenger has been used for a long time to remove oxygen in a container, and an example of applying this to a container wall is the invention of Japanese Patent Publication No. 62-1824. According to the above, a multilayer structure for packaging is obtained by laminating a layer formed by mixing a resin having oxygen permeability with a deoxidizer containing a reducing substance such as iron powder as a main component and a layer having an oxygen gas barrier property. It is described that

[0006] On the other hand, as a plastic container, it is desired to provide a container having further excellent storage stability of contents. In addition, degradable plastic, which disappears in the natural environment, has been attracting attention as an ideal solution for plastic waste.

[0007]

It is known that oxygen can be absorbed by adding a transition metal catalyst in a polyhydroxyalkanoate which is decomposed by the action of an enzyme released by bacteria or fungi to the outside of the body. However,
Due to its low gas barrier properties, when applied to containers,
There is a problem that the oxygen absorption rate for the contents is insufficient.

Further, the oxygen-absorbing resin composition containing a transition metal catalyst has an advantage that it can be applied to a substantially transparent packaging container, but the absorption rate of oxygen is still insufficient, Moreover, there is still a problem in the balance that oxygen in the container or oxygen that permeates through the container wall is effectively absorbed and the mechanical properties required for the container are sufficiently retained during storage. There is.

Therefore, an object of the present invention is to provide a plastic container which is excellent in oxygen absorption, gas barrier property, and transparency, and is also excellent in flavor retention of contents and storage stability of contents. It is to be. Furthermore, by using a biodegradable resin for the laminated resin as well as for a single layer, reduction to the natural world is performed at the time of disposal after use,
It is to provide an environmentally friendly plastic container.

[0010]

According to the present invention, a resin (A) mainly composed of polyglycolic acid is blended with a hydrocarbon resin (B) containing an unsaturated group and a transition metal catalyst (C). There is provided a plastic container comprising at least one oxygen-absorbing resin layer made of the above resin composition. In the plastic container of the present invention, 1. The resin composition contains 0.3 to 20.0% by weight of a hydrocarbon-based resin (B) containing an unsaturated group based on the resin (A) mainly containing polyglycolic acid, and 100 parts of a transition metal catalyst (C). To 1000 ppm, 1. 2. The hydrocarbon resin (B) containing an unsaturated group is a hydrocarbon resin modified with a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group and / or a carboxylic acid amide group. In the oxygen-absorbing resin layer, the resin (A) mainly composed of polyglycolic acid is present as a continuous matrix phase, and the hydrocarbon-based resin (B) containing an unsaturated group is present as a fine and uniform dispersed phase, and This hydrocarbon resin (B)
Exists in a flat state along the resin layer direction, It is preferable that the oxygen-absorbing resin layer further contains a plate-like filler and a resinous or wax-like dispersant. In the present invention, the base resin forming the oxygen-absorbing resin layer may contain other resin as long as it is polyglycolic acid alone or mainly polyglycolic acid. It may further contain vinyl alcohol. The plastic container of the present invention may of course be a multi-layered container, in which case it comprises at least one resin layer mainly composed of polyester or polyolefin or mainly composed of biodegradable polyester. It is preferable. The layer structure may be any known per se, for example, the polyester resin layer or the polyolefin resin layer, or the biodegradable resin layer as the inner and outer layers, the oxygen-absorbing resin layer as the intermediate layer May be

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In a plastic container of the present invention, a resin (A) containing polyglycolic acid as a main component, a hydrocarbon resin (B) containing an unsaturated group and a transition metal catalyst (C) are blended. It is characterized by having at least one oxygen-absorbing resin layer made of a resin composition.

Polyglycolic acid has the following formula Which is a polymer composed of repeating units represented by the following formula, and belongs to the simplest structure among aliphatic polyesters and hydroxyalkanoate type polyesters. This polyglycolic acid is biodegradable like other aliphatic polyesters, and is characterized by exhibiting low gas permeability with respect to oxygen and carbon dioxide gas. This is also one of the reasons for selecting polyglycolic acid as the base resin to be blended with.

In the present invention, the polyglycolic acid is mixed with a hydrocarbon resin containing an unsaturated group (hereinafter sometimes simply referred to as a hydrocarbon resin) and a transition metal catalyst to obtain oxygen. There is an advantage that the absorption is performed very effectively, and the oxygen absorption and the retention of the gas barrier property and the mechanical properties are effectively performed by the function sharing.

In a resin composition containing a hydrocarbon-based resin and a transition metal catalyst, radicals are generated by abstraction of hydrogen atoms from the hydrocarbon-based resin by the transition metal, and peroxy by addition of oxygen molecules to the radicals. Oxygen absorption is considered to occur through the elementary reactions of generation of radicals and abstraction of hydrogen atoms by peroxy radicals.

In the resin containing an unsaturated group used in the present invention, a hydrogen atom is easily abstracted at the position of the carbon atom adjacent to the carbon-carbon double bond, whereby a radical is generated. However, in a dispersion system in which a hydrocarbon resin is dispersed in a base resin, especially in the coexistence of a transition metal that does not cause deterioration of the resin in a normal state, there is an induction period in the generation of the radical or the addition of oxygen, It is considered that the elementary reaction of is not necessarily performed effectively.

On the other hand, in the system of polyglycolic acid, the hydrocarbon resin containing an unsaturated group and the transition metal catalyst used in the present invention, oxygen absorption is carried out effectively and rapidly. This is probably because radicals and oxygen addition are carried out quickly and effectively in the reaction system.

In addition, in the system of polyglycolic acid, hydrocarbon resin containing an unsaturated group and transition metal catalyst used in the present invention, a sea-island structure in which polyglycolic acid is a continuous phase and hydrocarbon resin is a dispersed phase However, there is an advantage that the hydrocarbon resin can be dispersed extremely finely and uniformly.

As already pointed out, in the system of the present invention, the absorption of oxygen is carried out exclusively by the hydrocarbon-based resin containing unsaturated groups, but the hydrocarbon-based resin is fine and uniform in the continuous matrix of polyglycolic acid. Since it exists as a dispersed phase like this, oxygen that tries to permeate in the thickness direction of the resin layer always encounters the hydrocarbon-based resin phase and captures it effectively. In this sense, it is particularly preferable that the hydrocarbon-based resin phase in the oxygen-absorbing resin layer exists in a flat state along the resin layer in terms of oxygen trapping property.

In the oxygen-absorbing resin layer containing an unsaturated group used in the container of the present invention, the polyglycolic acid is present in the form of a continuous matrix, while the hydrocarbon resin is present as a dispersed phase. Even after that, the continuous matrix has an advantage that the strength and the gas barrier property are maintained. Furthermore, this continuous matrix is biodegradable, giving the advantage that in single-layer or multi-layer containers with biodegradable polyester, the discarded containers can be easily disintegrated in the natural environment and reduced to the soil. Is.

[Resin (A) Mainly Containing Polyglycolic Acid] As the base resin of the oxygen absorbing resin layer in the plastic container of the present invention, a resin mainly containing polyglycolic acid is used. Polyglycolic acid has the following formula Is a resin mainly composed of repeating units consisting of, and even if this resin is a homopolymer consisting only of glycolate repeating units of formula (1), it is a copolymer containing repeating units other than the repeating units of formula (1). It may be a combination.

The repeating unit other than the above-mentioned formula (1) constituting the copolymer is an aliphatic polyester repeating unit other than polyglycolic acid, for example, the following formula: In the formula, R ₁ is an alkylidene group having 2 or more carbon atoms, or a linear or branched alkylene group, and a hydroxyalkanoate-type ester repeating unit consisting of In the formula, each of R ₂ and R ₃ is an alkylene group. Examples of such repeating units are 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxycaproate, 3-hydroxyheptanoate, 3-
Examples thereof include one or more repeating units such as hydroxyoctanoate, 3-hydroxynonanoate, 3-hydroxydecanoate, γ-butyrolactone, δ-valerolactone and ε-caprolactone.

In the polyglycolic acid resin used in the present invention, the repeating unit of the above formula (1) is present in an amount of 60% by weight or more, preferably 65% by weight or more, based on the resin. The amount of the repeating unit of the formula (1) in the polyglycolic acid resin has a great influence on the gas barrier property and the mechanical physical property of the container, and one method (2) or (3) is used.
The amount of repeating units has a great influence on the melting point, processing temperature, crystallinity, processing suitability, etc. of the resin, and homopolymers and copolymers with various copolymerization ratios are used depending on the required performance. To be done.

The polyglycolic acid resin used in the present invention is
It may be produced by any production method known per se, for example, glycolide (1,4-dioxane-2,3-
It may be produced by cationic ring-opening polymerization of dione) or polycondensation of glycolic acid or glycolic acid alkyl ester, but of course the polyglycolic acid resin used in the present invention is not limited to this production method.

The melting point of the polyglycolic acid resin used in the present invention is preferably 180 ° C. or higher, particularly 190 to 260 ° C. from the viewpoint of heat resistance and workability of the resin container. On the other hand, the molecular weight of the polyglycolic acid resin is 2 g expressed by the melt index (260 ° C., 2.16 kg).
/ 10 min or more, and particularly preferably in the range of 5 to 30 g / 10 min.

In the present invention, the above polyglycolic acid resin can be used alone as the base resin (A) of the oxygen absorbing resin layer, or a blend of this polyglycolic acid resin and another thermoplastic resin. Can also be used. As the other thermoplastic resin blended with the polyglycolic acid, for example, a saturated polyester resin having a hydroxyalkanoate unit as a main component, a biodegradable resin, and particularly an aliphatic polyester resin are preferable. As the aliphatic polyester resin, for example, a saturated polyester resin mainly containing a hydroxyalkanoate unit, for example, polyhydroxybutyrate (PHB), a random copolymer of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV). , Poly (ε-caprolactone) (P
CL), polylactic acid (PLLA), and aliphatic polyesters, particularly polybutylene succinate (PBS), polybutylene succinate adipate (PBAS), and the like. 60% by weight or more of the base resin (A), especially 65
It is desirable that the polyglycolic acid resin accounts for at least wt% in order to achieve the object of the present invention.

[Hydrocarbon Resin (B)] The hydrocarbon resin having an unsaturated group used in the present invention is a polymer having an oxidizing property by oxygen, but is generally a polymer derived from polyene. Is preferred. As such a polyene, a resin containing a unit derived from a polyene having 4 to 20 carbon atoms and a chain or cyclic conjugated or non-conjugated polyene is preferably used. Examples of these monomers include conjugated dienes such as butadiene and isoprene; 1,4-hexadiene, 3-methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4 -Hexadiene, 4,5-dimethyl
Chain non-conjugated dienes such as -1,4-hexadiene and 7-methyl-1,6-octadiene; methyl tetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2 -Norbornene, 5-vinylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, cyclic non-conjugated dienes such as dicyclopentadiene; 2,3-diisopropylidene-5-norbornene, 2-ethylidene -3-Isopropylidene-5-norbornene, trienes such as 2-propenyl-2,2-norbornadiene, chloroprene and the like can be mentioned.

These polyenes are incorporated in the form of homopolymers, random copolymers, block copolymers, etc., alone or in combination of two or more kinds, or in combination with other monomers. As the monomer used in combination with the polyene, α-olefin having 2 to 20 carbon atoms,
For example ethylene, propylene, 1-butene, 4-methyl-1-
Pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-Nonadecene, 1-Eikosen, 9-
Methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene can be mentioned. In addition, styrene, vinyltoluene, acrylonitrile, methacrylonitrile, vinyl acetate, methyl methacrylate, ethyl acrylate, etc. The body can also be used.

Specific examples of the polyene polymer include:
Polybutadiene (BR), polyisoprene (IR), butyl rubber (IIR), natural rubber, nitrile-butadiene rubber (NBR), styrene-butadiene rubber (SB
R), chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM), and the like, but not limited to these examples.

The carbon-carbon double bond in the polymer is
It is not particularly limited, and may be present in the main chain in the form of vinylene group or in the side chain in the form of vinyl group.

These polyene polymers have a polar group, particularly a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group and / or a carboxylic acid amide group. Also, it is preferable in terms of improving dispersibility. Examples of the monomer used for introducing these functional groups include the ethylenically unsaturated monomers having the above functional groups.

As these monomers, it is desirable to use unsaturated carboxylic acids or their derivatives. Specifically, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid. Α, β-unsaturated carboxylic acids such as acids, bicyclo [2,2,2]
1] Unsaturated carboxylic acids such as hept-2-ene-5,6-dicarboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and other α, β unsaturated carboxylic acid anhydrides, bicyclo Examples include unsaturated carboxylic acid anhydrides such as [2,2,1] hept-2-ene-5,6-dicarboxylic acid anhydride, and esters and amides of these unsaturated carboxylic acids.

The acid modification of the polyene polymer is carried out by using a resin having a carbon-carbon double bond as a base polymer and graft-copolymerizing an unsaturated carboxylic acid or its derivative with this base polymer by a method known per se. Although it is produced, it can also be produced by randomly copolymerizing the above-mentioned polyene and unsaturated carboxylic acid or its derivative.

The acid-modified polyene polymer which is particularly suitable for the purpose of the present invention is an unsaturated carboxylic acid or its derivative, which can be used as
It is preferably contained in an amount of 01 to 10 mol%. When the content of the unsaturated carboxylic acid or the derivative thereof is within the above range, the acid-modified polyene polymer is well dispersed in the thermoplastic resin, and oxygen is smoothly absorbed. Also, a hydroxyl group-modified polyene polymer having a hydroxyl group at the terminal can be favorably used.

The polyene polymer used in the present invention may be liquid or semi-solid, and has a Mooney viscosity ML1 + 4.
(100 ° C.) is preferably in the range of 10 to 250 from the viewpoint of processability of the oxygen-absorbing resin composition.

[Transition Metal Catalyst (C)] The transition metal catalyst used in the present invention is preferably a Group VIII metal component of the periodic table such as iron, cobalt and nickel, but other than Group I such as copper and silver. Metals: Group IV metals such as tin, titanium, zirconium,
Mention may be made of Group V metal components of vanadium, Group VI metal such as chromium, and Group VII metal components such as manganese. Among these metal components, the cobalt component has a high oxygen absorption rate and is particularly suitable for the purpose of the present invention.

The transition metal catalyst is generally used in the form of a low-valent inorganic acid salt or organic acid salt or complex salt of the above transition metal. Examples of the inorganic acid salt include halides such as chlorides, sulfur oxyacid salts such as sulfates, nitrogen oxyacid salts such as nitrates, phosphorus oxyacid salts such as phosphates, and silicates. On the other hand, examples of the organic acid salt include carboxylates, sulfonates, phosphonates, etc., and the carboxylates are suitable for the purpose of the present invention, and specific examples thereof include acetic acid, propionic acid, and isopropion. Acid, butanoic acid, isobutanoic acid, pentanoic acid, isopentanoic acid, hexanoic acid, heptanoic acid, isoheptanoic acid, octanoic acid, 2
-Ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid, decanoic acid, neodecanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, Lindelic acid, Tsuzu Examples thereof include transition metal salts such as acids, petroselinic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, formic acid, oxalic acid, sulfamic acid and naphthenic acid. On the other hand, as the transition metal complex, a complex with β-diketone or β-keto acid ester is used, and β-diketone or β-ketone is used.
Examples of the keto acid ester include acetylacetone,
Ethyl acetoacetate, 1,3-cyclohexadione, methylenebis-1,3-cyclohexadione, 2-benzyl-1,3-cyclohexadione, acetyltetralone,
Palmitoyltetralone, stearoyltetralone, benzoyltetralone, 2-acetylcyclohexanone,
2-benzoylcyclohexanone, 2-acetyl-1,
3-cyclohexanedione, benzoyl-p-chlorobenzoylmethane, bis (4-methylbenzoyl) methane, bis (2-hydroxybenzoyl) methane, benzoylacetone, tribenzoylmethane, diacetylbenzoylmethane, stearoylbenzoylmethane, palmitoylbenzoylmethane, Lauroylbenzoylmethane, dibenzoylmethane, bis (4-chlorobenzoyl) methane, bis (methylene-3,4-dioxybenzoyl) methane, benzoylacetylphenylmethane, stearoyl (4-methoxybenzoyl) methane, butanoylacetone, di Stearoylmethane, acetylacetone, stearoylacetone, bis (cyclohexanoyl) -methane, dipivaloylmethane and the like can be used.

[Oxygen-Absorbing Resin Layer] The resin composition used for the oxygen-absorbing resin layer of the present invention is a resin (A) mainly containing polyglycolic acid, and a hydrocarbon resin containing an ethylenically unsaturated group. (B) and a transition metal catalyst (C) are blended. As already pointed out, the hydrocarbon resin (B) is a component which itself is oxidized and absorbs oxygen, while the transition metal catalyst (C) promotes the oxidation of the hydrocarbon resin (B), It is a catalyst component that promotes it.

In the present invention, the hydrocarbon-based resin (B) is contained in an amount of 0.3 to 20% by weight, particularly 2 to 10% by weight, based on the resin (A) containing polyglycolic acid as a main component. It is preferable. If the amount of the hydrocarbon-based resin (B) is below the above range, the oxygen absorption rate will be considerably reduced as compared with the case where it is within the above range, which is not preferable. On the other hand, when the amount of the hydrocarbon-based resin (B) exceeds the above range, no particular advantage can be obtained in terms of oxygen absorption rate, and oxygen permeability through the layer of the oxygen-absorbing resin composition increases. Further, the physical properties of the resin are deteriorated and the moldability is deteriorated, which is not preferable.

On the other hand, the transition metal catalyst (C) is 100 to 100 based on the resin (A) mainly containing polyglycolic acid.
It is preferably contained in an amount of 0 ppm, particularly 150 to 500 ppm. When the amount of the transition metal catalyst (C) is less than the above range, the oxygen absorption rate becomes considerably lower than that in the above range, which is not preferable. On the other hand, when the amount of the transition metal catalyst (C) exceeds the above range, no particular advantage is obtained in terms of the oxygen absorption rate, and the oxygen-absorbing resin composition layer is significantly oxidized and deteriorated, so that the resin physical properties are It is not preferable because it lowers and the moldability deteriorates.

Resin (A) mainly composed of polyglycolic acid
Various means can be used for blending the unsaturated group-containing hydrocarbon resin (B) and the transition metal catalyst (C). There is no particular order in this formulation and blending may be done in any order. For example, by blending the hydrocarbon-based resin (B) with the resin (A) containing polyglycolic acid as a main component by dry blending or melt blending, a blend of both can be easily prepared. On the other hand, since the amount of the transition metal catalyst (C) is smaller than that of the resin (A) mainly composed of polyglycolic acid and the hydrocarbon resin (B), the transition metal catalyst (C) is generally used for homogeneous blending. C) is dissolved in an organic solvent, and this solution is mixed with a powder or granular resin (A) mainly containing polyglycolic acid and a hydrocarbon resin (B), and if necessary, this mixture is placed under an inert atmosphere. Good to dry.

Solvents for dissolving the transition metal catalyst (C) include alcohol solvents such as methanol, ethanol and butanol, ether solvents such as dimethyl ether, diethyl ether, methyl ethyl ether, tetrahydrofuran and dioxane, methyl ethyl ketone and cyclohexanone. A hydrocarbon solvent such as a ketone solvent or n-hexane or cyclohexane can be used, and it is generally preferable to use a concentration such that the concentration of the transition metal catalyst is 5 to 90% by weight.

The mixing of the resin (A) mainly composed of polyglycolic acid, the hydrocarbon resin (B) containing an unsaturated group and the transition metal catalyst (C), and the subsequent storage are carried out at the previous stage of the composition. It is preferable to carry out in a non-oxidizing atmosphere so that the above-mentioned oxidation does not occur. For this purpose, mixing or drying under reduced pressure or in a nitrogen stream is preferred. This mixing and drying is
It can be carried out in the pre-stage of the molding process using a vent type or dryer-equipped extruder or injection machine. Further, a master batch of a resin (A) and / or a hydrocarbon resin (B) mainly containing polyglycolic acid containing a transition metal catalyst (C) at a relatively high concentration is prepared, and this master batch is not blended. The oxygen-absorbing resin composition used in the present invention can also be prepared by dry blending with the resin (A) containing polyglycolic acid as a main component.

The oxygen absorbing layer used in the present invention preferably further contains a plate-like filler and a resinous or wax-like dispersant. As the plate-like filler, organic or inorganic fillers generally known as flakes are used, and for example, natural or synthetic minerals, ceramics, metals, or composites thereof are preferable. The resinous or wax-like dispersant used together with the plate-like filler is one having a non-polar group or a polar group, and includes natural wax, mineral wax or synthetic wax; vegetable oil, animal oil, mineral oil or Examples thereof include synthetic oils, semisolid substances such as higher fatty acids and soaps thereof, copolymer resins containing olefin as a constituent unit and monomer units having a polar group, and the like.

The oxygen absorbing layer used in the present invention may optionally contain an activator known per se, though it is not generally required. Suitable examples of activators include, but are not limited to, polyethylene glycol, polypropylene glycol, ethylene vinyl alcohol copolymers, ethylene / methacrylic acid copolymers, hydroxyl group- and / or carboxyl group-containing polymers such as various ionomers. is there. These hydroxyl group- and / or carboxyl group-containing polymers can be added in an amount of 30 parts by weight or less, particularly 0.01 to 10 parts by weight, per 100 parts by weight of the thermoplastic resin. The oxygen absorbing layer used in the present invention includes a filler, a colorant, a heat resistance stabilizer, a weather resistance stabilizer, an antioxidant, an antiaging agent, a light stabilizer, an ultraviolet absorber, an antistatic agent, a metal soap and a wax. Known resin compounding agents such as lubricants and modifying resins or rubbers can be compounded according to a method known per se. For example, the incorporation of the lubricant improves the penetration of the resin into the screw. Lubricants include metal soaps such as magnesium stearate and calcium stearate, hydrocarbon-based ones such as liquid, natural or synthetic paraffin, microwax, polyethylene wax, chlorinated polyethylene wax, and fatty acid-based ones such as stearic acid and lauric acid. , Stearic acid amide, valmitic acid amide, oleic acid amide, esylic acid amide, methylene bisstearamide, fatty acid monoamide type or bisamide type such as ethylene bisstearamide, butyl stearate, hydrogenated castor oil, ethylene Ester-based ones such as glycol monostearate, alcohol-based ones such as cetyl alcohol and stearyl alcohol,
And their mixed systems are commonly used. The amount of the lubricant added is suitably in the range of 50 to 4000 ppm on the basis of thermoplasticity.

In the oxygen-absorbing resin layer of the container of the present invention, the unsaturated group-containing hydrocarbon resin (B) is dispersed in the resin (A) mainly containing polyglycolic acid in a granular or spindle shape. The maximum length of the dispersion is 1 μmm
The following is preferable from the viewpoint of oxygen absorption and oxygen barrier properties of the oxygen absorption layer. This oxygen-absorbing resin layer preferably exists in a state where the hydrocarbon-based resin (B) is flat along the layer direction when it is incorporated in a container.
Such a distribution state causes the hydrocarbon-based resin (B) to be atomized and dispersed in the oxygen-absorbing resin layer, and at the time of molding a container or a container precursor, the oxygen-absorbing resin layer should have a flow orientation or a stretch orientation. It is obtained by giving. That is, in this oxygen-absorbing resin layer, the resin (A) containing polyglycolic acid as a main component has a continuous structure and the hydrocarbon resin (B) as a dispersed phase, and the dispersed particle size of the dispersed phase Is suppressed within the above range, the oxygen absorption by the hydrocarbon resin (B) is efficiently performed, and the polyglycolic acid is mainly contained even after the oxygen absorption by the hydrocarbon resin (B) is performed. Since the continuous phase of the resin (A) is maintained, there is an advantage that the oxygen barrier property is maintained.

[Plastic Container] The plastic container of the present invention may have a single-layer structure or an arbitrary multi-layer structure under the condition that the oxygen-absorbing resin layer is provided, but in general, at least one resin is used. It is preferable to take a multi-layered structure further including layers in terms of the mechanical strength and gas barrier property of the container.

The laminated constitution of the oxygen-absorbing resin layer and the other resin layer in the plastic container is not particularly limited and may be arbitrary, but from the viewpoint of gas barrier properties and mechanical properties of the container. , At least one oxygen-absorbing resin layer
It is preferable that the resin layer exists as an intermediate layer, and other resin layers exist inside and outside the oxygen-absorbing resin layer.

As the resin used for the multi-layer resin container, all the conventionally known resins can be used. For example, a thermoplastic polyester such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate; polycarbonate. Acrylic-butadiene-styrene copolymer (ABS resin); Polyacetal resin; Nylon 6, Nylon 66, MXD
Nylons such as 6 nylon and their copolymerized nylons;
Acrylic resins such as polymethylmethacrylate; isotactic polypropylene; polystyrene; low-, medium- or high-density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, styrene-butadiene Examples thereof include thermoplastic elastomers. Further, as the biodegradable resin used for the multilayer resin container, a saturated polyester resin having a hydroxyalkanoate unit as a main component, for example, polyhydroxybutyrate (PHB), 3-hydroxybutyrate (3H) is used.
B) and 3-hydroxyvalerate (3HV) random copolymer, branched 3-hydroxybutyrate (3H
B) and 3-hydroxyvalerate (3HV), a random copolymer, poly (ε-caprolactone) (PC
L), polylactic acid (PLLA), aliphatic polyester,
In particular, polybutylene succinate (PBS) and polybutylene succinate adipate (PBAS) can be preferably used alone or in combination of two or more. Furthermore, a polyester composed of 20% by weight or more of an aliphatic dibasic carboxylic acid and an aromatic dibasic carboxylic acid other than the above, such as polybutylene terephthalate / adipate, can also be used as the biodegradable resin.

In the plastic container of the present invention, a gas barrier resin layer may be used in addition to the above resin layer. The most suitable examples of the gas barrier resin include polyvinyl alcohol resins and polyvinyl copolymers, ethylene-vinyl alcohol copolymers, cyclic olefin copolymers, and barrier resins such as polyacrylonitrile.

A suitable example of the container laminated structure is as follows, where the oxygen absorbing layer is represented by OAR, the laminated resin is represented by CR, and the gas barrier resin is represented by GR. Further, which layer is to be the inner surface side can be freely selected depending on the purpose. Two-layer structure: CR / OAR, GR / OAR, Three-layer structure: CR / OAR / CR, CR / OAR / GR, Four-layer structure: CR / GR / OAR / CR, CR / OAR /
CR / GR, 5-layer structure: CR / OAR / CR / OAR / CR, CR /
OAR / GR / OAR / CR, 6-layer structure: CR / OAR / CR / OAR / GR / CR, 7-layer structure: CR / OAR / CR / GR / CR / OAR /
CR, etc.

A suitable example of a laminated structure used in a container in which a biodegradable resin is laminated is OAR for the oxygen absorbing layer and B for the laminated resin.
The R and gas barrier resins are represented as GR, and are as follows. Further, which layer is to be the inner surface side can be freely selected depending on the purpose. Two-layer structure: BR / OAR, GR / OAR, Three-layer structure: BR / OAR / BR, BR / OAR / GR, Four-layer structure: BR / GR / OAR / BR, BR / OAR /
BR / GR, five-layer structure: BR / OAR / BR / OAR / BR, BR /
OAR / GR / OAR / BR, 6-layer structure: BR / OAR / BR / OAR / GR / BR, 7-layer structure: BR / OAR / BR / GR / BR / OAR /
BR, etc.

In the production of the above laminated body, an adhesive resin may be interposed between the resin layers, if necessary. Further, a thermosetting adhesive resin such as an isocyanate type or an epoxy type is also used for the adhesive lamination of the preformed gas barrier resin film and the moisture resistant resin film.

In the multilayer resin container of the present invention, the thickness of the oxygen-absorbing resin layer is not particularly limited, but is generally 3 to 1.
It is preferably in the range of 00 μm, particularly 5 to 90 μm. That is, if the thickness of the oxygen-absorbing resin layer is thinner than a certain range, the oxygen-absorbing performance is poor, and even if it is thicker than a certain range, there is no particular advantage in terms of the oxygen-absorbing property, and the resin amount is increased. This is because it is disadvantageous in terms of the properties and container characteristics such as flexibility and deterioration of flexibility of the material.

In the multi-layered resin container of the present invention, the total thickness is generally 30 to 70, though it varies depending on the use.
00 μm, especially 50 to 5000 μm,
On the other hand, the thickness of the oxygen-absorbing intermediate layer is preferably 0.5 to 95%, especially 1 to 50% of the total thickness.

The plastic container of the present invention can be manufactured by a method known per se except that the above-mentioned oxygen-absorbing resin layer is used. For example, a film, a sheet or a tube is formed by melt-kneading the resin composition with an extruder and then extruding the resin composition into a predetermined shape through a T-die, a circular die (ring die) or the like,
A T-die method film, blown film or the like can be obtained. By biaxially stretching the T-die film,
A biaxially stretched film is formed. Further, the resin composition is melt-kneaded by an injection machine and then injected into an injection mold to produce a container or a preform for producing the container.
Further, the resin composition is extruded into a certain molten resin mass through an extruder and compression-molded with a mold to manufacture a container or a preform for manufacturing the container. The molded product may be in the form of a film, a sheet, a parison or pipe for forming a bottle or a tube, a preform for forming a bottle or a tube, or the like. The formation of a bottle from a parison, pipe or preform is facilitated by pinching off the extrudate with a pair of split molds and blowing a fluid into it. Further, a stretched blow bottle or the like can be obtained by cooling the pipe or the preform, heating it to a stretching temperature, stretching it in the axial direction, and blow-stretching it in the circumferential direction by fluid pressure. Furthermore, the film or sheet is subjected to means such as vacuum forming, pressure forming, overhang forming, plug assist forming, etc. to obtain a cup-shaped or tray-shaped packaging container or a lid material composed of a film or sheet. To be

A packaging material such as a film can be used as a packaging bag in various forms, and the bag can be produced by a bag-making method known per se. Ordinary pouches with three-sided or four-sided seals, Examples thereof include gusseted pouches, standing pouches, and pillow packaging bags, but are not limited to these examples.

For producing the multi-layer extrusion molded article, a co-extrusion molding method known per se can be used. For example, the number of extruders corresponding to the kind of the resin is used and the multi-layer multiple die is used as described above. Extrusion molding may be performed in the same manner. Further, in the production of the multilayer injection-molded article, the number of injection molding machines corresponding to the type of resin can be used to produce the multilayer injection-molded article by the co-injection method or the sequential injection method. Further, an extrusion coating method or sandwich lamination can be used for producing the multilayer film or sheet, and the multilayer film or sheet can be produced by dry lamination of a preformed film.

The multilayer container of the present invention is useful as a container capable of preventing the flavor of the contents from being deteriorated due to oxygen. Fillable contents include beer, wine, fruit juice, carbonated soft drinks, etc. for beverages, fruits, nuts, vegetables, meat products, infant foods, coffee, jams, mayonnaise, ketchup, edible oils, dressings, sauces, etc. Other examples include, but are not limited to, pharmaceutical products, cosmetics, gasoline, and other contents that easily deteriorate in the presence of oxygen.

[0059]

EXAMPLES Next, the present invention will be described with reference to specific examples. The present invention is not limited to the examples below.

(Material) Polyglycolic acid resin was used as the base resin of the oxygen absorbing resin composition, and maleic anhydride modified polybutadiene and cobalt fatty acid salt were used as the oxygen absorbing agent. As a laminated resin other than biodegradable,
Polyethylene terephthalate was used. As the biodegradable resin, polylactic acid or polybutylene terephthalate adipate resin was used. As the plate-like filler, there was used a filler having an average aspect ratio of 200, an average thickness of 0.6 μm, and a glittering mica pigment whose surface was treated with titanium dioxide, which was impregnated with an adhesive olefin wax at room temperature.

(Oxygen-Absorbing Resin Composition) A fatty acid cobalt salt was added to the outer surface of the polyglycolic acid resin pellets in an amount corresponding to a cobalt concentration of 350 ppm, which was then fed to a twin-screw extruder to prepare maleic anhydride-modified polybutadiene. weight%
It was blended and melt-kneaded.

(Molding into a container) For molding into a preform, a co-injection machine consisting of two injection machines and a hot runner was used. Injection molding of polyethylene terephthalate is 3
Polylactic acid and polybutylene terephthalate adipate resin are injection molded at a temperature range of up to 220 ° C, and polyglycolic acid resin composition is injection molded at a temperature of up to 250 ° C. / Polyglycolic acid resin composition / polyethylene terephthalate / polyglycolic acid resin composition / polyethylene terephthalate and polylactic acid / polyglycolic acid resin composition / polylactic acid / polyglycolic acid resin composition / polylactic acid and polybutylene terephthalate A 2-type 5-layer co-injection preform of adipate resin / polyglycolic acid resin composition / polybutylene terephthalate adipate resin / polyglycolic acid resin composition / polybutylene terephthalate adipate resin was produced. Next, the preform was reheated to a temperature of up to 150 ° C. using a blow molding machine, and then blow molded into a bottle having a volume of 350 ml.

(Evaluation of Oxygen Barrier Property) A molded bottle was degassed with a gas displacement device, then filled with nitrogen gas, and tap water 1 was added.
After filling 0 ml, it was stored under the condition of 40 ° C.-RH 30% for 21 days, and the oxygen concentration in the bottle was measured by a gas chromatography device to obtain the oxygen concentration in the container.

(Evaluation of biodegradability) Compost prepared by curing molded bottles from cow dung and mulch (adjusted to a compost temperature of 70 ° C)
When it was stored for 6 months and it was confirmed that there was no shape or residual plastic pieces, the biodegradability was rated as ◯. Moreover, when the plastic piece remaining in the compost was confirmed, it was marked with x.

[Example 1] Polyethylene terephthalate was used as the laminated resin other than biodegradable, and a polyglycolic acid resin in which an oxygen absorbent was mixed in the oxygen absorbing resin layer was used. Material / polyethylene terephthalate / polyglycolic acid resin composition / polyethylene terephthalate / polyglycolic acid resin composition / polyethylene terephthalate, a two-layer, five-layer multi-layer preform is manufactured and blow molded to obtain a body wall thickness of 300 μm and a volume of 350 ml. A multilayer bottle was molded. The results obtained are shown in Table 1.

Example 2 Polylactic acid was used as the biodegradable polyester, and a polyglycolic acid resin composition containing an oxygen absorbent in the oxygen absorbing resin layer was used. A multi-layer preform of lactic acid / polyglycolic acid resin composition / polylactic acid of 2 layers and 5 layers was manufactured and blow molded to obtain a body part having a thickness of 300 μm and a thickness of 350 μm.
A ml volume multi-layer bottle was molded. Table 2 shows the obtained results.
Shown in.

Example 3 A polyglycolic acid resin containing the oxygen absorbent described in Example 2 was mixed with a lustrous mica pigment whose surface was treated with titanium oxide, and an olefin wax having an adhesive property at room temperature was used as a luminescent mica standard. Example 2 was repeated except that a resin composition obtained by melt-blending 2% by weight of the filler containing 10% by weight was used. The obtained results are shown in Table 2.

Example 4 A polybutylene terephthalate adipate resin / polyglycol was prepared by using a polyglycolate resin composition in which a polybutylene terephthalate adipate resin was used as a biodegradable polyester and an oxygen absorbent was mixed in an oxygen absorbing resin layer. 2 of acid resin composition / polybutylene terephthalate adipate resin / polyglycolic acid resin composition / polybutylene terephthalate adipate resin
A multi-layer preform of 5 layers of seeds was manufactured, and a multi-layer bottle having a body wall thickness of 300 μm and a volume of 350 ml was molded by blow molding. The obtained results are shown in Table 2.

[Comparative Example 1] In Example 1, instead of the polyglycolic acid resin composition containing an oxygen absorbent,
A multilayer bottle similar to that of Example 1 was molded except that the polyglycolic acid resin was used alone. The results obtained are shown in Table 1.

[Comparative Example 2] In Example 2, instead of the polyglycolic acid resin composition containing an oxygen absorbent,
A multilayer bottle was produced in the same manner as in Example 2 except that the polyglycolic acid resin alone was used. Table 2 shows the obtained results.
Shown in.

[Comparative Example 3] In Example 1, instead of the polyglycolic acid resin composition containing an oxygen absorbent,
A multilayer bottle was produced in the same manner as in Example 1 except that the ethylene-vinyl alcohol copolymer was used. The obtained results are shown in Table 2.

[0072]

[Table 1]

[0073]

[Table 2]

[0074]

EFFECTS OF THE INVENTION According to the present invention, a resin composition comprising a resin (A) mainly composed of polyglycolic acid and a hydrocarbon-based resin (B) containing an unsaturated group and a transition metal catalyst (C). By providing at least one oxygen-absorbing resin layer consisting of, a plastic container excellent in oxygen-absorbing property, gas barrier property, and transparency, and also excellent in retaining contents is provided. You can Furthermore, a plastic container having biodegradability and barrier properties can be provided by a single layer or by laminating biodegradable resin.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B65D 65/40 ZBP B65D 65/40 ZBPD 65/46 BSG 65/46 BSG 81/26 BRQ 81/26 BRQH C08K 3/08 C08K 3/08 7/00 7/00 C08L 29/04 C08L 29/04 B // C08L 101/16 101/16 (C08L 67/04 C08L 101: 02 101: 02) (72) Inventor Watanabe Yuto 1-8 Shimonotani-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Toyo Seikan Co., Ltd. Technical Division Tsurumi Branch Room F-term (reference) 3E067 BB14A BB25A CA04 CA06 CA11 CA30 GB11 GB13 GD10 3E086 AC22 BA02 BA04 BA15 BB01 BB05 BB90 CA01 CA11 CA21 CA28 CA29 DA08 4F100 AJ11A AJ11H AK03B AK21A AK41B AK41C AK42 AK54A AK56A AL05A BA02 BA03 BA10A BA10C CA05A CA23A DA01 DE02A GB16 JC00C JD03A JL08A 4J002 BE02X BL003 CF18W DE186EG GG01 4J200 AA05 AA06 AA28 BA13 BA22 BA25 DA17 EA13

Claims (9)

[Claims] 1. At least one resin composition comprising a resin (A) mainly composed of polyglycolic acid and a hydrocarbon resin (B) containing an unsaturated group and a transition metal catalyst (C). A plastic container having an oxygen-absorbing resin layer. 2. An oxygen-absorbing resin comprising a resin composition containing a polyglycolic acid-based resin (A) and an unsaturated group-containing hydrocarbon resin (B) and a transition metal catalyst (C). A plastic container characterized in that the layer further comprises at least one oxygen-absorbing high-gas barrier resin composition layer containing a plate-like filler and a resinous or wax-like dispersant. 3. The resin composition comprises 0.3 to 20.0% by weight of a hydrocarbon-based resin (B) containing an unsaturated group based on a resin (A) mainly composed of polyglycolic acid, and a transition metal catalyst. The plastic container according to claim 1 or 2, which contains 100 to 1000 ppm of (C). 4. The hydrocarbon resin (B) containing an unsaturated group is a hydrocarbon resin modified with a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group and / or a carboxylic acid amide group. Claim 1 characterized by the above.
4. The plastic container according to any one of 1 to 3. 5. The plastic container according to claim 1, wherein the resin (A) containing polyglycolic acid as a main component further contains polyvinyl alcohol. 6. In the oxygen-absorbing resin layer, the resin (A) mainly composed of polyglycolic acid is a continuous matrix phase, and the hydrocarbon resin (B) containing an unsaturated group is a fine and uniform dispersed phase. 6. The plastic container according to any one of claims 1 to 5, wherein the hydrocarbon-based resin (B) containing the unsaturated group is present in a flat state along the resin layer direction. . 7. The plastic container according to claim 1, further comprising at least one resin layer mainly composed of polyester or polyolefin. 8. The plastic container according to any one of claims 1 to 6, further comprising at least one biodegradable resin layer mainly composed of biodegradable polyester. 9. The resin layer mainly comprising the polyester or the polyolefin or the biodegradable resin layer is present as an inner and outer layer, and the oxygen absorbing resin layer is present as an intermediate layer. The described plastic container.