JP2003020344A - Polyglycolic acid molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat containing polyglycolic acid, which is excellent in fluidity in a molten state, capable of forming a uniform thin film, has remarkable biodegradability, and can be rapidly composted. To provide a molded article formed using a plastic resin material. SOLUTION: The following formula (1): A polyglycolic acid containing 60% by weight or more of a repeating unit represented by the following formula: wherein the melt viscosity of the polyglycolic acid in the molded product is 20 ° C. below the melting point.
When measured under conditions of high temperature and shear rate of 100 / sec,
A molded product having a viscosity of 20 Pa · s or more and less than 500 Pa · s. Specific molded articles include oriented films, stretch blow containers, multilayer hollow containers, and multilayer films.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various polyglycolic acid moldings formed from a thermoplastic resin material containing polyglycolic acid as a main component, and more specifically, it has excellent fluidity in a molten state and is uniform. A molded product formed from a thermoplastic resin material containing polyglycolic acid as a main component, which can be formed into a thin film, has outstanding biodegradability, and is capable of rapid composting, or uses this as a core layer The present invention relates to a multi-layer molded product, for example, a poly-glycolic acid molded product such as a compression molded product, an extrusion molded product, an oriented film, a stretch blow container, a multi-layer hollow container, and a multi-layer film.

[0002]

2. Description of the Related Art In recent years, the increase of plastic waste has become a big social problem. As one of the means for solving this problem, research and development of biodegradable polymer materials are under way. Among the biodegradable polymer materials, polyglycolic acid is excellent in gas barrier properties such as oxygen gas barrier property, carbon dioxide gas barrier property, and water vapor barrier property in addition to exhibiting biodegradability (disintegration in soil). It also has excellent heat resistance and mechanical strength.

Therefore, various molded products using polyglycolic acid have been proposed. Specific examples thereof include polyglycolic acid oriented film (JP-A-10-60136) and polyglycolic acid stretch blow container (JP-A-10-136).
337772) and the like. Further, a multilayer hollow container (Japanese Patent Laid-Open No. 10-138371) in which a layer formed of polyglycolic acid is arranged in a core layer, a gas barrier composite film (Japanese Patent Laid-Open No. 10-80990), and the like have been proposed. .

Molded articles formed by using these polyglycolic acid are excellent in gas barrier properties, heat resistance, mechanical strength and the like, and can exhibit various properties such as disintegration in soil. However, these molded products do not progress rapidly in soil disintegration sufficiently and require a relatively long period of time for composting. Further, it is difficult to form polyglycolic acid into a uniform thin film, and there is a limit to weight reduction and cost reduction. Therefore, it has been difficult for the molded product formed by using these polyglycolic acid to disintegrate in the soil in a short period of time to promote composting, or to develop the application in a field where a uniform thin film is required.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polymer having excellent fluidity in a molten state, capable of forming a uniform thin film, excellent biodegradability, and capable of rapid composting. Molded article formed using a thermoplastic resin material containing glycolic acid, for example, compression molded article, extruded article,
It is intended to provide various molded products such as oriented films, stretch blow containers, multilayer hollow containers, and multilayer films.

Conventionally, in order to obtain a molded article having excellent physical properties such as mechanical strength, measurement was carried out at a temperature 20 ° C. higher than the melting point (hereinafter, abbreviated as “melting point + 20 ° C.”) and a shear rate of 100 / sec. It has been said that it is necessary to use a high molecular weight polyglycolic acid having a melt viscosity of 500 Pa · s or more (see the above-mentioned publications). Contrary to this technical common sense, the present inventors formed various molded products using polyglycolic acid having a relatively low melt viscosity, and as a result, they have excellent fluidity in a molten state and can form a uniform thin film. Moreover, it was found that the soil collapsed in a relatively short period of time and the composting was quickly performed. Further, when polyglycolic acid undergoes melt molding processing, its melt viscosity is likely to change, but by measuring the melt viscosity of polyglycolic acid in the molded product, it is possible to clearly identify the molded product excellent in the above-mentioned various properties. can do. The present invention has been completed based on these findings.

[0007]

Thus, according to the present invention, the following formula (1)

[0008]

[Chemical 7]

A molded article containing polyglycolic acid as a main component, which contains 60% by weight or more of the repeating unit represented by the formula (1), wherein the melt viscosity of the polyglycolic acid in the molded article is 20 ° C. higher than the melting point and shearing is performed. Provided is a molded product having a speed of 20 Pa · s or more and less than 500 Pa · s when measured at a speed of 100 / sec.

Further, according to the present invention, there is provided an oriented film containing polyglycolic acid as a main component, containing 60% by weight or more of the repeating unit represented by the above formula (1). The oriented film has a melt viscosity of 20 Pa · s or more and less than 500 Pa · s when measured at a temperature 20 ° C. higher than the melting point and a shear rate of 100 / sec.

Further, according to the present invention, there is provided a stretch blow container containing polyglycolic acid as a main component, containing 60% by weight or more of the repeating unit represented by the above formula (1),
The melt viscosity of the polyglycolic acid in the stretch blow container is
Provided is a stretch blow container having a temperature of 20 ° C. higher than the melting point and a shear rate of 100 / sec, which is 20 Pa · s or more and less than 500 Pa · s.

According to the present invention, there is provided a layer structure in which a thermoplastic resin layer is formed on at least one side of a layer containing polyglycolic acid as a main component and containing 60% by weight or more of the repeating unit represented by the above formula (1). A multilayer molded article having the polyglycolic acid as a main component, wherein the melt viscosity of the polyglycolic acid is 20 ° C. higher than the melting point and the shear rate is 1.
20 Pa · s or more 50 when measured under the condition of 00 / sec
Provided is a multi-layer molded product having a viscosity of less than 0 Pa · s.

Further, according to the present invention, a layer having a thermoplastic resin layer formed on at least one surface of a layer containing polyglycolic acid as a main component and containing 60% by weight or more of the repeating unit represented by the above formula (1). A multi-layer hollow container having a constitution, wherein the melt viscosity of polyglycolic acid in the layer containing polyglycolic acid as a main component is 20 Pa when measured at a temperature 20 ° C higher than the melting point and a shear rate of 100 / sec.・ S
A multi-layer hollow container having a pressure of 500 Pa · s or more is provided.

Further, according to the present invention, a layer having a thermoplastic resin layer formed on at least one surface of a layer containing polyglycolic acid as a main component and containing 60% by weight or more of the repeating unit represented by the above formula (1). A multi-layer film having a constitution, wherein the melt viscosity of polyglycolic acid in the layer containing polyglycolic acid as a main component is 20 Pa when measured at a temperature 20 ° C. higher than the melting point and a shear rate of 100 / sec.
A multilayer film having a thickness of s or more and less than 500 Pa · s is provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION 1. Polyglycolic Acid The polyglycolic acid of the present invention has the following formula (1):

[0016]

[Chemical 8]

It is a homopolymer or a copolymer containing a repeating unit represented by:

The content of the repeating unit represented by the formula (1) in the polyglycolic acid is 60% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, and the upper limit is 100% by weight. %. If the content of the repeating unit represented by the formula (1) is too low, the gas barrier property and heat resistance are impaired.

In the polyglycolic acid, as the repeating unit other than the repeating unit represented by the formula (1), for example,
At least one repeating unit represented by the following formulas (2) to (6) can be contained.

[0020]

[Chemical 9]

(Where n = 1 to 10 and m = 0 to 10)

[0022]

[Chemical 10]

(Where, j = 1 to 10)

[0024]

[Chemical 11]

(In the formula, R ₁ and R ₂ are each independently
It is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. k
= 2-10)

[0026]

[Chemical 12]

[0027]

[Chemical 13]

The melting point of the homopolymer of polyglycolic acid can be lowered by introducing the other repeating units represented by the formulas (2) to (6) in a proportion of 1% by weight or more. By lowering the melting point of polyglycolic acid, the processing temperature can be lowered and the thermal decomposition at the time of melt processing can be reduced. Further, by copolymerization, the crystallization rate of polyglycolic acid can be controlled to improve extrusion processability and stretching processability. If the content of other repeating units in the copolymer is too large, the crystallinity originally possessed by polyglycolic acid may be impaired, which may adversely affect the gas barrier property and the like.

The physical properties such as the melt viscosity and the melting point of the polyglycolic acid in the present invention described below are measured as the physical properties of polyglycolic acid in the molded product after the melt molding, unless otherwise specified. .

The polyglycolic acid of the present invention is a relatively low molecular weight polymer. The melt viscosity of a polymer can be used as an index of molecular weight. The polyglycolic acid of the present invention is
When its melting point is represented by Tm, the melt viscosity η * measured under the conditions of temperature (Tm + 20 ° C.) (that is, a temperature 20 ° C. higher than the melting point and corresponding to a normal melt processing temperature) and a shear rate of 100 / sec. Is 20 Pa · s or more and 500 Pa
It is less than s, preferably 30 to 400 Pa · s, and more preferably 40 to 350 Pa · s.

The melt viscosity of polyglycolic acid is 500 Pa.
When it is less than s, the fluidity in a molten state is excellent, a uniform thin film can be formed, and the disintegration property in soil is significantly promoted. The melt viscosity of polyglycolic acid is 500 Pa
When it is less than s, the melt processability at a high temperature may tend to be lower than that in the case of polyglycolic acid having a high melt viscosity. Molding processing such as stretch blow molding becomes possible. Further, when the melt viscosity of polyglycolic acid is low, the melt processing temperature can be lowered, so that thermal deterioration of polyglycolic acid can be prevented.

The melting point Tm of the polyglycolic acid of the present invention is
The temperature is preferably 150 ° C or higher, more preferably 190 ° C or higher, and particularly preferably 210 ° C or higher. The melting enthalpy ΔHm of the polyglycolic acid of the present invention is preferably 20 J / g or more, more preferably 30 J / g or more, and particularly preferably 40 J / g or more. Polyglycolic acid whose melting point or melting enthalpy is too low is presumed to have reduced crystallinity due to disorder of the chemical structure in the molecule. Therefore, molded products such as oriented films and stretch blow containers formed of such polyglycolic acid tend to have low barrier properties and insufficient heat resistance.

In the polyglycolic acid of the present invention, the density of the non-oriented crystallized product is preferably 1.50 g / cm ³ or more,
It is preferably 1.52 g / cm ³ or more, and particularly preferably 1.53 g / cm ³ or more. Polyglycolic acid having too low a density is presumed to have a low crystallinity due to disorder of the chemical structure in the molecule. Therefore, the oriented film formed of such a low-density polyglycolic acid, a molded article such as a stretch blow container has a low crystallinity,
Gas barrier properties, heat resistance, and strength may be insufficient.

2. Method for producing polyglycolic acid Polyglycolic acid has the following formula [I]

[0035]

[Chemical 14]

As shown in, it can be synthesized by dehydration polycondensation of glycolic acid. In addition, polyglycolic acid has the following formula [II]

[0037]

[Chemical 15]

(Wherein R represents an alkyl group, and the number of carbon atoms in the alkyl group is preferably about 1 to 5). be able to. further,
Polyglycolic acid has the following formula [III]

[0039]

[Chemical 16]

As shown in, it can be synthesized by ring-opening polymerization of glycolide (ie, bimolecular cyclic ester of glycolic acid).

Polyglycolic acid comprises glycolide (that is, 1,4-dioxane-2,5-dione) in the form of a small amount of a catalyst (for example, a cationic catalyst such as tin organic carboxylate, tin halide and antimony halide). In the presence of about 1
It is preferable to synthesize by a method of heating at a temperature of 20 ° C. to about 250 ° C. and ring-opening polymerization. The ring-opening polymerization is preferably performed by a bulk polymerization method or a solution polymerization method.

The polyglycolic acid can be obtained by a polycondensation method in which glycolic acid or a glycolic acid alkyl ester is heated or dehydrated or dealcoholized in the presence or absence of a catalyst. A polycondensation method of desalting using a salt of glycolic acid can also be adopted. According to these polycondensation methods, polyglycolic acid having a relatively low melt viscosity can be easily obtained.

In order to synthesize a polyglycolic acid copolymer, ethylene oxalate (ie, 1,4-dioxane-2,3-dione), lactide, or lactone can be used as a comonomer in each of the above synthesis methods. (Eg, β-propiolactone, β-butyrolactone, pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc.), trimethylene carbonate, and 1,3-dioxane. Cyclic monomers; hydroxycarboxylic acids such as lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 6-hydroxycaproic acid or their alkyl esters; ethylene glycol, 1,4-butanediol, etc. An aliphatic diol,
A substantially equimolar mixture of an aliphatic dicarboxylic acid such as succinic acid or adipic acid or an alkyl ester thereof; or a copolymer of two or more kinds of these in combination with glycolide, glycolic acid, or a glycolic acid alkyl ester as appropriate. Good.

The polyglycolic acid copolymer is synthesized by subjecting polyglycolic acid and another polymer having a repeating unit selected from the above formulas (2) to (5) to transesterification under heating. You can

As the glycolide used as a monomer in the ring-opening polymerization method, those obtained by a conventional sublimation depolymerization method of a glycolic acid oligomer can be used, which is disclosed in JP-A-9-328481. The one obtained by the "solution phase depolymerization method" is
It is preferable because a large amount can be obtained with high purity and high yield.

In the solution-phase depolymerization method, a mixture containing (1) a glycolic acid oligomer and at least one high-boiling polar organic solvent having a boiling point in the range of 230 to 450 ° C. is added under normal pressure or reduced pressure. By heating to a temperature at which depolymerization of the oligomer occurs, (2) the oligomer is dissolved in the solvent until the residual ratio (volume ratio) of the melt phase of the oligomer becomes 0.5 or less, and (3) the same. Further heating is continued at a temperature to depolymerize the oligomer, (4) the produced dimeric cyclic ester (that is, glycolide) is distilled out together with the high-boiling polar organic solvent, and (5) glycolide is removed from the distillate. to recover.

Examples of the high boiling polar organic solvent include bis (alkoxyalkyl ester) phthalate such as di (2-methoxyethyl) phthalate, alkylene glycol dibenzoate such as diethylene glycol dibenzoate, benzyl butyl phthalate and dibutyl phthalate. Aromatic carboxylic acid esters, aromatic phosphoric acid esters such as tricresyl phosphate, and the like can be mentioned, and they are usually used in a proportion of 0.3 to 50 times (weight ratio) with respect to the oligomer. If necessary, polypropylene glycol, polyethylene glycol, tetraethylene glycol or the like can be used together with the high boiling point polar organic solvent as a solubilizing agent for the oligomer.
The depolymerization temperature of the glycolic acid oligomer is usually 230.
C. or higher, preferably 230 to 320.degree. The depolymerization is performed under normal pressure or reduced pressure, and the depolymerization is 0.1 to 90.
Depolymerization is preferably performed by heating under a reduced pressure of 0 kPa (1 to 900 mbar).

3. Thermoplastic resin material In the present invention, using a resin material containing polyglycolic acid as a main component, various molded products, for example, compression molded products such as trays, extruded products, oriented films, stretch blow containers, multilayer molded products, A multilayer hollow container and a multilayer film are produced, and more specifically, a thermoplastic resin material containing a specific polyglycolic acid is used as a raw material.

As the thermoplastic resin material, netoresin of polyglycolic acid can be used alone. In addition, as the thermoplastic resin material, polyglycolic acid,
A composition containing an inorganic filler, another thermoplastic resin, a plasticizer or the like can be used within a range that does not impair the object of the present invention. The blending amount of the inorganic filler, other thermoplastic resin, the plasticizer and the like is appropriately selected from the viewpoints of gas barrier property, biodegradability, uniform thin film forming property and the like.
When other components are mixed, the proportion of polyglycolic acid in the thermoplastic resin material is usually 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more.

The amount of the inorganic filler compounded is preferably 0 to 30 parts by weight, based on 100 parts by weight of polyglycolic acid.
More preferably 0 to 10 parts by weight, particularly preferably 0 to 5
Parts by weight. When compounding an inorganic filler, the lower limit is preferably 0.01 part by weight, more preferably 0.0
5 parts by weight.

The amount of the other thermoplastic resin compounded is preferably 0 to 50 parts by weight, more preferably 0 to 30 parts by weight, based on 100 parts by weight of polyglycolic acid. When blending another thermoplastic resin, the lower limit is preferably 0.0
5 parts by weight.

The blending amount of the plasticizer is 10% of polyglycolic acid.
It is preferably 0 to 50 parts by weight, more preferably 0 to 30 parts by weight, and particularly preferably 0 to 10 parts by weight, relative to 0 parts by weight. When a plasticizer is added, its lower limit is preferably 0.01 part by weight, more preferably 0.05 part by weight. However, when the polyglycolic acid used in the present invention has a sufficiently low melt viscosity, it is often unnecessary to add a plasticizer.

As the inorganic filler, alumina, silica, silica-alumina, zirconia, titanium oxide, iron oxide, boron oxide, calcium carbonate, calcium silicate,
Calcium phosphate, calcium sulfate, magnesium carbonate, magnesium silicate, magnesium phosphate, magnesium sulfate, kaolin, talc, mica, ferrite,
Carbon, silicon, silicon nitride, molybdenum disulfide, glass, inorganic powder such as potassium titanate, whiskers,
Fiber etc. are mentioned. These inorganic fillers may be used alone or in combination of two or more.

Other thermoplastic resins include, for example, lactic acid homopolymers and copolymers, ethylene oxalate homopolymers and copolymers, ε-caprolactone homopolymers and copolymers, and polysuccinic acid. Ester, polyhydroxybutanoic acid, hydroxybutanoic acid-hydroxyvaleric acid copolymer, cellulose acetate, polyvinyl alcohol, starch,
Polyglutamic acid ester, natural rubber, polyethylene,
Polypropylene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, polymethylmethacrylate, polystyrene, styrene-butadiene-
Styrene block copolymer, styrene-ethylene / butylene-styrene block copolymer, ABS resin, MBS
Examples thereof include resins and ethylene-vinyl alcohol copolymers.

Examples of the plasticizer include phthalic acid esters such as di (methoxyethyl) phthalate, dioctylphthalate, diethylphthalate and benzylbutylphthalate;
Benzoic acid esters such as diethylene glycol dibenzoate and ethylene glycol dibenzoate; aliphatic dibasic acid esters such as octyl adipate and octyl sebacate; aliphatic tribasic acid esters such as tributyl acetylcitrate; dioctyl phosphate, tricresyl phosphate And the like; epoxy-based plasticizers such as epoxidized soybean oil; polyalkylene glycol esters such as polyethylene glycol sebacate and polypropylene glycol laurate; and the like.

In the present invention, various additives such as a heat stabilizer, a light stabilizer, a moisture-proofing agent, a waterproofing agent, a water repellent, a lubricant, a release agent, a coupling agent, a pigment and a dye may be optionally heated. It can be contained in the plastic resin material. These various additives are used in effective amounts according to their intended use.
The thermoplastic resin material, by a conventional method, polyglycolic acid alone, or polyglycolic acid, an inorganic filler, a thermoplastic resin, a plasticizer, and one or more other components such as various additives are supplied to the kneading extruder, Cylinder temperature Tm ~ 255
Melt kneading at a temperature of ℃ (normally 150 to 255 ℃),
Extruded in strands, cooled and cut into pellets.

4. Molded product Using the thermoplastic resin material containing the polyglycolic acid of the present invention, extrusion molding, compression molding (press molding), solution casting method, etc., trays of various shapes, deep-drawn molded products, sheets, films, Any shaped article such as fibers can be formed. Among these molded products, oriented films and stretch blow containers are preferable. Further, a multilayer hollow container and a multilayer film having a layer structure in which a thermoplastic resin layer is formed on at least one surface of a layer formed of a thermoplastic resin material containing polyglycolic acid are preferable.

These oriented films, stretch blow containers,
In the multilayer hollow container and the multilayer film, the gas barrier property of polyglycolic acid can be sufficiently exhibited.
In addition, it is possible to uniformly thin the layer (film, body of container, multilayer hollow container, core layer of multilayer film, etc.) made of a thermoplastic resin material containing polyglycolic acid.

5. Oriented Film The oriented film of the present invention can be produced by melt-extruding the above-mentioned netoresin of polyglycolic acid or a composition containing the polyglycolic acid, stretching / orienting, and optionally heat-setting. . As the melt film forming method, a method such as uniaxial stretching by a flat die method, sequential biaxial stretching, simultaneous biaxial stretching, or inflation biaxial stretching by a circular die method can be adopted. The following method can be mentioned as a preferable method.

(1) Roll method: A method of producing a uniaxially oriented flat film by stretching a sheet melt-extruded using a T die in a machine direction (MD) through a stretching roll.

(2) Tenter method: The sheet melt-extruded using a T-die is oriented in the machine direction (MD) by a stretching roll, and then oriented in the transverse direction (TD) using a tenter, and biaxially oriented flat. A method of manufacturing a film.

(3) Inflation method: Using an inflation ring die, melt-extruding into a tube shape, quenching to a crystallization temperature (Tc ₁ ) or lower, and then injecting gas into the tube to expand and stretch the tube. how to.
In this way, a biaxially stretched film can be obtained by stretching also between the nip rolls in the machine direction. As a method of cooling after melt extruding into a tube shape, there are a method of airing, a method of immersing in cold water, and the like. Among these methods,
A particularly preferable method for producing an oriented film is as follows.

In the roll method, the thermoplastic resin material is supplied to an extruder equipped with a T die, extruded into a sheet at a temperature range of Tm to 255 ° C. (usually 150 to 255 ° C.), and immediately cooled by a cooling drum or a refrigerant. to Tc ₁ below using, preferably rapidly cooled to a temperature below the glass transition temperature (Tg), then the temperature range of Tg~Tc ₁ (usually 30 to 120 ° C.),
Preferably Tg- (Tg + 10 ° C) (usually 30-48)
In the temperature range is passed through the stretching rolls ° C.), 1-fold excess 20 times or less in the MD (preferably by stretching and orientation at a draw ratio of 2 to 10 times), Tc ₁ optionally ~ (Tm + 10
C) in the temperature range (usually 70 to 240 ° C.) for 1 second to 3 hours (preferably 3 seconds to 0.5 hours), and heat-set under a fixed length or under tension to produce a uniaxially oriented flat film. be able to. If the sheet extrusion temperature from the T-die exceeds 255 ° C., the decomposition of the polymer and the accompanying rapid decrease in the molecular weight, foaming, etc. are likely to occur, and a sheet-like material suitable for the next stretching process may not be obtained. . If the stretching temperature exceeds Tc ₁ , the sheet-like material will be almost crystallized, and stretching orientation may be almost impossible. The obtained uniaxially oriented film can be easily made into a split yarn by further opening in the width direction.

In the tenter method, the thermoplastic resin material is
It is supplied to an extruder equipped with a die, extruded in a sheet form at a temperature of Tm to 255 ° C (usually 150 to 255 ° C), and immediately cooled to Tc ₁ or less, preferably Tg or less by using a cooling drum or a refrigerant. Then, similarly to the roll method, Tg ~
Temperature of Tc ₁ (usually 30 to 120 ° C.), preferably Tg
To (Tg + 10 ° C.) (usually 30 to 48 ° C.), through a stretching roll, the MD is stretched at a stretching ratio of more than 1 time and 10 times or less (preferably 2 to 8 times), and then,
In the temperature range of Tg to Tc ₁ (usually 30 to 120 ° C.), preferably Tg to (Tg + 20 ° C.) (usually 30 to 58 ° C.), TD is more than 1 time and 10 times or less (preferably 2 to 8).
At a temperature of Tc ₁ to (Tm + 10 ° C.) (usually 70 to
A biaxially oriented flat film can be produced by heat setting at 240 ° C. for 1 second to 3 hours (preferably 3 seconds to 30 minutes).

In the inflation method, the thermoplastic resin material is fed to an extruder equipped with an inflation ring die, and the temperature is Tm to 255 ° C. (usually 150 ° C. to 25 ° C.).
Melt extruded into a tube at 5 ° C.) and immediately cooled to Tc ₁ or less, preferably Tg or less, and then Tg to Tc
₁ (usually 30 to 120 ° C.), preferably Tg to (Tg +
In a temperature range of (10 ° C.) (usually 30 to 48 ° C.), inflation is performed so that the blow ratio is more than 1 time and 10 times or less (preferably 2 to 8 times), and the take-up speed is 0.5 to 100.
m / min (preferably 1 to 50 m / min), and the MD ratio is controlled to be more than 1 time and 10 times or less (preferably 2 to 8 times), and is withdrawn through a nip roll, and if necessary, Tc ₁ At a temperature of (Tm + 10 ° C.) (usually 70 to 240 ° C.) for 1 second to 3 hours (preferably 3 seconds to 0.5 hours), heat-setting under a fixed length or under tension to give a tubular shape. An axially oriented film can be produced.

The two surfaces of the oriented film of the present invention are aligned, and using a sealer, (Tm-20 ° C) to (Tm + 100 ° C)
At a temperature of, preferably Tm to (Tm + 50 ° C.),
By heat sealing or fusion sealing for usually 0.01 to 100 seconds, preferably 0.1 to 20 seconds,
Bags can be manufactured. As the sealer, a hot knife sealer, an impulse sealer, a high frequency sealer, an ultrasonic sealer and the like can be used.

In each of the methods for producing an oriented film of the present invention, a film obtained by only stretching and orienting and omitting heat setting becomes a heat shrinkable film having a high heat shrinkage ratio.

The thickness of the oriented film of the present invention is usually 1 to
It is 500 μm, preferably 3 to 300 μm, and more preferably 5 to 200 μm. Even if the oriented film of the present invention is formed into an extremely thin film having a thickness of 40 μm or less, the variation in thickness is small and thin film molding is possible.

The oriented film of the present invention is a film disintegrating in soil which has a low environmental load. That is, the polyglycolic acid oriented film of the present invention has a depth of 10 cm in soil.
When it is buried in, it usually collapses within 6 months and loses its original shape. For example, in the case of a conventional polylactic acid film, the glass transition temperature (Tg) is too high, which makes it difficult to compost under normal conditions. On the other hand, since the oriented film of the present invention is formed of polyglycolic acid having a Tg that is not so high, it can be composted under normal conditions. In addition, the soil disintegration rate is significantly higher than that of the conventional oriented film obtained by using polyglycolic acid having a high melt viscosity.

The oriented film of the present invention containing no inorganic filler or containing a small amount of inorganic filler has almost no color, high transparency, and extremely low haze value.

By using a thermoplastic resin material containing a specific polyglycolic acid, it is possible to obtain an oriented film having a very low oxygen permeability. More specifically, according to the present invention, oxygen permeability (measured at a temperature of 23 ° C. and a relative humidity of 80%; converted to a thickness of 25 μm; JIS K-7
126), but usually 50 cm ³ / m ² · day · a
tm or less, preferably 30 cm ³ / m ² · day · atm
Or less, more preferably 10 cm ³ / m ² · day · atm
The oriented film having the following high barrier property can be obtained.

The oriented film of the present invention is also excellent in carbon dioxide gas barrier property, and has a carbon dioxide gas permeability (measured at a temperature of 23 ° C. and a relative humidity of 80%; converted to a thickness of 25 μm; JIS K
-7126), but is usually 300 cm ³ / m ² · da
y · atm or less, preferably 100 cm ³ / m ² · day
・ Atm or less, more preferably 30 cm ³ / m ²・ day
・ Atm or less. The oriented film of the present invention has a good water vapor barrier property, and has a water vapor transmission rate (measured at a temperature of 40 ° C. and a relative humidity of 90%; converted to a thickness of 25 μm; JISK-02.
80), but usually 100 g / m ² · day or less,
It is preferably 50 g / m ² · day or less, more preferably 30 g / m ² · day or less.

The oriented film of the present invention can be used for various purposes by itself or by applying a moisture-proof coating or moisture-proof laminate. This oriented film can be used by forming it into a bag-shaped molded body or the like. The oriented film of the present invention has features such as high gas barrier properties, heat shrinkage resistance, and high transparency.

According to the present invention, the heat shrinkage (130 ° C., 1
(Measured in 0 minutes) is usually 30% or less, preferably 20%
% Or less, more preferably 10% or less, an oriented film having a low heat shrinkage can be obtained. Such low heat shrinkage films are used at high temperatures, for example, wrap films used in microwave ovens, trays, containers for instant food by injecting hot water, packaging for retort foods requiring high temperature sterilization and medical use. It is suitable for applications such as equipment packaging materials.

The polyglycolic acid oriented film of the present invention can be easily formed into a thin film. However, a thin oriented film can be used for film-to-film or film-to-film rewinding during film winding or rewinding during film production or processing, or during film rewinding or rewinding during use. The magnitude of friction between metal surfaces becomes a problem. If the friction is too great, the film may be broken or wrinkled during the winding and rewinding operations, making these operations difficult. 0.01 to 5 parts by weight, preferably 0.02 to 3 parts by weight of the powdery inorganic filler is added to 100 parts by weight of the specific polyglycolic acid.
By using the thermoplastic resin material contained in an amount of, by weight, more preferably 0.03 to 2 parts by weight, the dynamic friction coefficient μk (23 ° C.) between films is 0.35.
Or less, preferably 0.33 or less, more preferably 0.3
A slippery film of 0 or less can be obtained.

An unstretched film was prepared using a thermoplastic resin material containing 0.5 to 100 parts by weight of an inorganic filler in the form of powder with respect to 100 parts by weight of polyglycolic acid, and the unstretched film was subjected to area magnification. When the film is stretched in the uniaxial or biaxial direction so that the ratio is 3 times or more, preferably 4 times or more, the printing ink is easily spread and an oriented film having excellent printability can be obtained.

Examples of the use of the oriented film of the present invention include food packaging materials, medical equipment packaging materials, wrap films, clothing packaging materials, doll packaging materials, fresh packaging materials, vegetable packaging materials, egg packs, cushion materials, mulch. Film, carrier bag, garbage bag,
Examples include sanitary product packaging materials, disposable diapers, adhesive tapes, magnetic tapes, floppy (R) disks, microwave oven wrap films, retort food packaging materials, and instant food packaging materials. The non-heat-fixed oriented film can be used as a heat-shrinkable film. The split yarn can be used as a cord material for loading and agriculture.

6. Stretch Blow Container The stretch blow container of the present invention comprises a thermoplastic resin material composed of a netoresin of polyglycolic acid or a composition containing the polyglycolic acid having specific physical properties, Tm to 2;
Molding is performed at a resin temperature of 55 ° C. to produce a substantially amorphous preform, and the preform is treated at a resin temperature of (glass transition temperature Tg of polyglycolic acid Tg + 70 ° C.) or less,
In addition to stretching in the longitudinal direction to more than 1 time and 10 times or less, air is blown simultaneously or sequentially to obtain a blow ratio of 1.5-
Blow molding into 10 hollow containers, and if necessary,
Crystallization temperature of polyglycolic acid Tc ₁ to (Tm + 10
(° C) for 1 second to 30 minutes by heat setting.

The resin temperature during preform (parison) molding is in the range of melting point Tm to 255 ° C. Polyglycolic acid has a Tm of about 220 ° C. in the case of a homopolymer, but it is generally produced by copolymerizing it with a comonomer such as ethylene oxalate, lactide, lactones, trimethylene carbonate and 1,3-dioxane. Lower than. Therefore, the resin temperature during preform molding is usually 150 to 255 ° C., preferably 190 to 250 ° C.
More preferably, it is 200 to 245 ° C. Resin temperature is 2
If it exceeds 55 ° C, the polyglycolic acid is likely to undergo thermal decomposition, and a satisfactory preform cannot be obtained.

The preform is molded as a substantially amorphous preform. When the preform is in a crystalline state, the tension at the time of stretching becomes large in the next stretching step, which makes stretching difficult. A substantially amorphous preform can be obtained by quenching a molten resin.

The temperature conditions for stretch blow molding are (Tg + 7)
0 ° C.) or lower. The resin temperature during stretch blowing is (Tg +
If the temperature exceeds 70 ° C., the molecular chain of the polymer is too active, so that the stretch orientation may be immediately relaxed even if stretch blow, and the orientation may disappear or may be significantly reduced.

In the case of the cold parison method, after the parison obtained by injection molding or extrusion molding is once cooled and solidified, the resin temperature is from Tg to (Tg + (Tg +) during stretch blow molding.
Reheat to 70 ° C. range. In the case of the hot parison method, the parison obtained by injection molding or extrusion molding is cooled, but stretch blow molding is performed while the resin is not solidified. That is, when the preform is a hot parison, the preform is melt-molded at a temperature of Tm to 255 ° C, and then (Tg-30 ° C) to (Tg + 70).
C.) and stretch blow molding while the resin does not solidify. Even if the melt-formed preform is rapidly cooled and supercooled to a temperature lower than Tg, it is possible to manufacture a stretch-blow container by performing stretch blow molding immediately before the resin is solidified.

The polyglycolic acid has a Tg of about 38 ° C. in the case of a homopolymer, but by copolymerizing with a comonomer such as ethylene oxalate, lactide, lactones, trimethylene glycol and 1,3-dioxane, The value fluctuates. Therefore, the resin temperature during stretch blow molding is (Tg + 70 ° C.) or less, but preferably 30 to
100 degreeC, More preferably, it is 35-90 degreeC.

The preform exceeds 1 time in the longitudinal direction, and 10
Stretching to less than twice, but in the case of a bottomed parison, usually,
Stretch using a stretch rod. In the case of a hollow pipe-shaped parison, both ends are held by holders and stretched in the length direction (longitudinal direction). The stretching ratio in the machine direction is preferably 1.
It is about 5 to 5 times. The blow ratio is usually 1.5 to 10,
It is preferably 1.8 to 9, and more preferably 2.0 to 8. If the blow ratio is less than 1.5, the orientation of the molecular chains will be insufficient, the crystallinity will be insufficient, and harmful coarse spherulites will be formed, whereby sufficient tensile strength will not be exhibited, and barrier properties and heat resistance will be exhibited. The transparency and transparency may be insufficient. The blow ratio refers to the ratio of the diameter (maximum diameter) of the container to the diameter of the parison formed in the container in blow molding. The step of blowing by blowing air can be performed simultaneously with the stretching in the machine direction or after the stretching in the machine direction (sequentially).
To do.

In the final step of stretch blow molding, if necessary, a temperature of Tc ₁ to (Tm + 10 ° C.) (usually 70 to 2)
Heat set at 40 ° C. for 1 second to 30 minutes (usually 2 seconds to 10 minutes). By stretch blow molding, the side wall of the body is sufficiently stretched and oriented, high barrier property, high elasticity and high strength,
A heat-resistant stretch-blown container can be obtained. On the other hand, in the conventional extrusion blow molding method (for example, Japanese Patent Laid-Open No. 6-278785) that does not involve the conventional stretch orientation and the injection blow molding method, the stretch orientation of the side wall of the body hardly occurs during the molding of the hollow container. It doesn't happen or happens only inadequately,
The resulting hollow container has unsatisfactory barrier properties, mechanical properties, and heat resistance.

More specifically, the stretch blow molding method which can be used in the present invention includes the following various methods.

(1) Injection / Stretching Blow Two-Step Method The thermoplastic resin material containing the polyglycolic acid is
It is supplied to an injection molding machine, injection-molded in a mold at a resin temperature of Tm to 255 ° C. to prepare a bottomed parison, and then cooled and solidified to obtain a preform composed of a cold parison having a resin temperature of less than Tg, Then, preform Tg ~
After being reheated to a resin temperature of (Tg + 70 ° C.), it is moved into a blow molding die, and is stretched by a stretching rod in the longitudinal direction to more than 1 time and 10 times or less, and simultaneously or sequentially blows air. It is blow-molded into a hollow container having a blow ratio of 1.5 to 10 and heat-fixed if necessary.

(2) Injection / Stretching Blow One-Step Method A thermoplastic resin material containing polyglycolic acid is supplied to an injection molding machine and injection-molded in a mold at a resin temperature of Tm to 255 ° C. to obtain a bottomed bottom. After making the parison, cool it,
A preform made of unsolidified hot parison having a resin temperature of (Tg + 70 ° C.) or less, and then,
The preform is moved into a blow molding die and stretched by a stretching rod in the longitudinal direction to more than 1 time and 10 times or less, and at the same time or sequentially, air is blown in to blow a hollow ratio of 1.5 to 10 Blow-mold into containers and heat set if necessary. In this method, the preform maintains the residual heat of injection molding and moves to the blow molding step. You may add the temperature adjustment process of a hot parison.

(3) Extrusion / Stretching Blow Two-Step Method (Part 1) A thermoplastic resin material containing polyglycolic acid was supplied to an extruder equipped with a parison die, and Tm to 255 ° C.
After making a hollow pipe by extrusion molding at the resin temperature of
It is cooled and solidified to a temperature of less than g, cut into a certain length to obtain a preform composed of cold parison, and then the preform is reheated to a resin temperature of Tg to (Tg + 70 ° C.), and then both ends thereof are held by a holder. Then, the film is stretched to more than 1 time and 10 times or less in the length direction, and then one end is pinched off to make it have a bottom, and then it is moved into a blow molding die and blown with air to obtain a blow ratio of 1.5. It blow-molds in the hollow container of No. 10, and heat-fixes as needed.

(4) Extrusion / Stretching Blow Two-Step Method (Part 2) A thermoplastic resin material containing polyglycolic acid was supplied to an extruder equipped with a parison die, and Tm to 255 ° C.
After making a hollow pipe by extrusion molding at the resin temperature of
After solidifying by cooling to a temperature of less than g and cutting into a fixed length to obtain a preform made of cold parison, the preform was reheated to a resin temperature of Tg to (Tg + 70 ° C.), and then one end thereof was pinched off. It is made to have a bottom, and then moved into a blow molding die, and is stretched by a stretching rod in the longitudinal direction to more than 1 time and 10 times or less, and at the same time or successively, air is blown to blow ratio 1.5 to 10. It is blow molded into a hollow container and heat-fixed if necessary.

(5) Extrusion / Stretching Blow One-Step Method (Part 1) A thermoplastic resin material containing polyglycolic acid was supplied to an extruder equipped with a parison die, and Tm to 255 ° C.
After making a hollow pipe by extrusion molding at the resin temperature of
After cooling to a resin temperature of (Tg + 70 ° C.) or less and cutting into a constant length to obtain a hot parison preform,
Hold both ends with a holder and exceed 1 times in the length direction,
After stretching to 10 times or less, and then pinching off one end to make it bottomed, it is moved into a blow molding die and blown with air to blow mold into a hollow container having a blow ratio of 1.5 to 10, Heat set if necessary. You may add the temperature adjustment process of a hot parison.

(6) Extrusion / Stretching Blow One-Step Method (Part 2) A thermoplastic resin material containing polyglycolic acid was fed to an extruder equipped with a parison die, and Tm to 255 ° C.
After making a hollow pipe by extrusion molding at the resin temperature of
After cooling to a resin temperature of (Tg + 70 ° C.) or less and cutting into a constant length to obtain a hot parison preform,
Pinch off one end to make it bottomed, and then move it into the blow molding die and stretch it to more than 1 time and 10 time or less in the longitudinal direction by a stretching rod, and blow air by blowing simultaneously or sequentially. It is blow molded into a hollow container having a ratio of 1.5 to 10 and heat-fixed if necessary. You may add the temperature adjustment process of a hot parison.

According to the present invention, a stretch blow container having an internal volume of 25 ml or more can be obtained, but the internal volume can be appropriately determined according to the purpose of use. In the stretch blow molding, it is preferable that the stretch blow container, in which the mouth portion and the bottom portion are molded, usually has a flat portion at the bottom so that it can stand upright independently. However, even if it does not have a flat portion on the bottom such as a round bottom, it can be erected by attaching an annular band (a kind of hook).

The stretch-blow container of the present invention is a soil-disintegratable molded product having a low environmental load. That is, the stretch blow container made of the polyglycolic acid of the present invention, in the soil,
When it is buried at a depth of 10 cm, it usually collapses within 6 months and loses its original shape.

The stretch-blow container of the present invention containing no inorganic filler or containing a small amount of inorganic filler is almost colorless, has high transparency, and has an extremely low haze value.

The stretch-blow container of the present invention can exhibit gas barrier properties, heat resistance, mechanical properties, etc. by sufficiently stretching and orienting the molecular chains of the polymer on the side wall of the body during stretch blow molding. .

According to the present invention, a stretch blow container having a high oxygen and carbon dioxide gas barrier property can be obtained. The stretch blow container of the present invention has an oxygen permeability of the body side wall (measured at a temperature of 23 ° C. and a relative humidity of 80%, and has a thickness of 50 μm).
Is usually 150 cm ³ / m ² · day · atm or less, preferably 50 cm ³ / m ² · day · atm or less,
It is more preferably 20 cm ³ / m ² · day · atm or less. The stretch blow container of the present invention has a carbon dioxide permeability of the side wall of the body (measured at a temperature of 23 ° C. and a relative humidity of 80%, and a thickness of 5).
(Converted to 0 μm) is 300 cm ³ / m ² · day · atm or less, preferably 100 cm ³ / m ² · day · atm or less, more preferably 30 cm ³ / m ² · day · atm or less. The stretch blow container of the present invention has a moisture permeability of the side wall of the body (measured at a temperature of 40 ° C. and a relative humidity of 90%, and a thickness of 50 μm).
(converted to m) is usually 100 g / m ² · day or less, preferably 50 g / m ² · day or less, more preferably 30.
It is not more than g / m ² · day.

The stretch-blow container of the present invention is as it is,
Alternatively, by applying a moisture-proof coat, moisture-proof laminate, etc., for example, as a container for carbonated drinking water, soft drink, seasoning, edible oil, liquor, fruit juice, a general-purpose barrier hollow container such as a PET bottle can be substituted. .

In the stretch blow container of the present invention, since the side wall of the body portion is highly elastic, even if the wall thickness thereof is reduced to about half that of the conventional hollow container, the stretch blow container is strong and can be filled with contents. It is difficult to transform. Therefore, the economical effect of reducing the wall thickness due to the high elasticity is extremely large.

According to the present invention, it is possible to obtain a stretch blow container having excellent heat resistance. The heat shrinkage ratio (130 ° C., 10 minutes) of the body side wall of the stretch-blow container of the present invention is usually as low as 30% or less, preferably 20% or less, more preferably 10% or less. Such a hollow container having a low heat shrinkage ratio is suitable as a container for foods such as seasonings that require high temperature sterilization. The heat shrinkage is 30%
The use of a hollow container having a temperature of more than 130 ° C. at a high temperature of 130 ° C. or more causes excessive deformation, which may cause a problem.

The stretch-blown container of the present invention can be used for various purposes by taking advantage of the features such as high barrier property, heat resistance, transparency and mechanical strength. In particular,
Examples include containers for carbonated drinking water, soft drinks, edible oils, fruit juices, liquors, etc .; containers for drinking water, detergents, cosmetics; seasoning containers that require high temperature sterilization, baby bottles and the like.

7. Multilayer Hollow Container The multilayer hollow container of the present invention contains at least one thermoplastic resin layer (hereinafter sometimes referred to as a base resin layer), and neat resin of polyglycolic acid having specific physical properties or the polyglycolic acid. A multi-layer hollow container having a layer (hereinafter, may be simply referred to as "PGA layer") formed of a thermoplastic resin material including the composition described above, and has a gas barrier property. If necessary, an adhesive layer can be interposed between the layers.

The overall thickness of the side wall of the body of the multilayer hollow container of the present invention is usually 5 μm to 5 mm, preferably 10 μm to 3 m.
m, more preferably 20 μm to 2 mm. If this thickness is too thin, the mechanical strength will be insufficient, and if it is too thick, it will result in excessive quality when used as a hollow container, and it will be costly, which is not preferable from the viewpoint of productivity and economy.

The basic layer structure of the multi-layer hollow container of the present invention is as follows. However, the adhesive layer is omitted. Further, a thermoplastic resin material containing polyglycolic acid is abbreviated as PGA.

(1) Thermoplastic resin / PGA (2) Thermoplastic resin 1 / PGA / thermoplastic resin 1 (3) Thermoplastic resin 1 / PGA / thermoplastic resin 2

The multi-layer hollow container of the present invention may have the same or different resin layers additionally laminated depending on various required characteristics as long as it has the above-mentioned basic layer constitution. Good (eg thermoplastic / PGA / PGA). The method for forming the thermoplastic resin layer and the polyglycolic acid layer in layers is not particularly limited, and various processing methods such as a method of laminating by a coextrusion method or a coinjection method can be adopted.

In the multilayer hollow container of the present invention, examples of the thermoplastic resin other than PGA used for the thermoplastic resin layer include, for example, ultra low density polyethylene (VLDPE),
Linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDP
E), high density polyethylene (HDPE), polypropylene (PP), ethylene / propylene rubber (EPM), ethylene / vinyl acetate copolymer (EVA), ethylene / acrylic acid ester copolymer (EEA), ionomer (IO) Polyolefin such as; polyethylene terephthalate (PET), polyethylene naphthalate (PE
N) and other polyesters; polystyrene (PS), high-impact polystyrene (HIPS), styrene-butadiene-styrene block copolymer (SBS), hydrogenated SB
Polystyrene resin such as S (that is, SEBS);
Polyvinyl chloride (PVC) resin such as hard polyvinyl chloride and soft polyvinyl chloride, polycarbonate (P
C), polyamide (PA), polyurethane (PU), ethylene / vinyl alcohol copolymer (EVOH), polyvinylidene chloride resin (PVDC) and the like. Other thermoplastics that have a low environmental impact include:
For example, polylactic acid, polysuccinic acid ester, polycaprolactone and the like are preferable.

In the multilayer hollow container of the present invention, these thermoplastic resin layers are used as a single layer or multiple layers. The thickness of the thermoplastic resin layer is usually 4 μm to 5 mm, preferably 10
The range of μm to 3 mm, and more preferably 20 μm to 2 mm is desirable from the viewpoint of workability and economy.

In the present invention, in order to enhance the adhesiveness between the thermoplastic resin layer (base resin layer) and the polyglycolic acid layer,
An adhesive layer can be interposed between the layers. Examples of the adhesive used for the adhesive layer include carboxylated polyolefin, epoxidized polyolefin, ethylene
Examples thereof include polymers such as vinyl acetate copolymer, ionomer, polyurethane, epoxy resin, SBS, SEBS, polychloroprene, styrene / butadiene copolymer rubber (SBR), and natural rubber (NR). The carboxylated polyolefin is a polyolefin in which a carboxyl group is introduced by modifying the polyolefin with an unsaturated acid monomer such as acrylic acid, methacrylic acid or maleic anhydride.
The carboxyl group may be introduced by either a copolymerization method or a graft method. Further, the unsaturated acid monomer may be used in combination with a methacrylic acid ester, an acrylic acid ester, a vinyl-based monomer such as vinyl acetate.

The epoxidized polyolefin is a polyolefin in which an epoxy group is introduced by modifying the polyolefin with an epoxy group-containing monomer such as glycidyl methacrylate. The epoxy group may be introduced by either a copolymerization method or a graft method. Moreover, you may use together the said epoxy group containing monomer and vinyl type monomers, such as a methacrylic acid ester, an acrylic acid ester, and vinyl acetate. Among these, carboxylated polyolefin and ethylene
A vinyl acetate copolymer is particularly preferable from the viewpoint of adhesiveness and processability. The thickness of the adhesive layer is usually 0.5 μm to 2 m.
m, preferably 2 μm to 1 mm, more preferably 3 μm
The range is from 0.5 mm. If the thickness is less than 0.5 μm, the adhesiveness may be insufficient. If the thickness exceeds 2 mm, the cost is high and it is economically disadvantageous.

In the multilayer hollow container of the present invention, a layer (PGA) made of a thermoplastic resin material containing polyglycolic acid is used.
By arranging the layers, it is possible to obtain a multilayer hollow container having excellent gas barrier properties such as oxygen gas barrier properties and carbon dioxide gas barrier properties. The thickness of the PGA layer is usually 1
-30 μm, preferably 3-20 μm. In the multi-layer hollow container of the present invention, it is preferable to arrange the PGA layer in the core layer. In that case, even if the PGA layer has a thin thickness of 10 μm or less, and even 3 to 5 μm, a layer having a uniform thickness. Can be formed.

The body side wall of the layered hollow container of the present invention has an oxygen gas permeability and / or a carbon dioxide gas permeability of generally 1/2 or less, preferably 1 or less as compared with those values of the thermoplastic resin layer. / 5 or less, more preferably 1/10 or less. That is, the gas barrier multi-layer hollow container of the present invention is selected from, for example, polyolefin, polyester, polystyrene, polyvinyl chloride, polycarbonate, polylactic acid, polysuccinic acid ester, polycaprolactone, polyamide, EVOH, polyurethane and PVDC. By combining a PGA layer as a gas barrier property improver with a thermoplastic resin layer made of a resin,
It is possible to obtain a hollow container in which at least one of the oxygen gas barrier property and the carbon dioxide gas barrier property is surprisingly improved as compared with the thermoplastic resin layer. In addition, the multi-layer hollow container of the present invention has a very small decrease in its gas barrier property even when subjected to a treatment under high temperature and high humidity.

The purpose of making the hollow container multi-layered is to obtain the required properties by multi-layering, which cannot be obtained by a single material. Specifically, it is to impart gas barrier properties to oxygen, carbon dioxide gas, etc., impart heat seal properties, improve moisture resistance, improve mechanical strength, and greatly reduce costs.

The method for producing the multilayer hollow container of the present invention can be roughly classified into a multilayer extrusion blow molding method and a multilayer injection blow molding method. These blow molding methods include
There are a stretch blow molding method of stretching in a uniaxial or biaxial direction during blow molding and a non-stretching blow molding method of not stretching.

In the multi-layer extrusion blow molding, first, a multi-layer parison composed of a thermoplastic resin material containing polyglycolic acid, at least one thermoplastic resin, and, if necessary, an adhesive is molded. For this purpose, each resin material heated and melted by each extruder is flown into a multi-layer parison molding die (usually a circular die), and is merged simultaneously or sequentially inside the die to extrude a tubular parison from the die. . Before the melt-extruded parison is solidified, it is sandwiched by split molds, one end of the parison is pinched, air is blown into the parison to blow it to the mold wall, and then cooled. After cooling, the mold is opened and the molded product is taken out. When blowing, the parison is cooled in the supercooled state or at the crystallization temperature (Tc
_A uniaxially or biaxially oriented molded product can be obtained by uniaxially or biaxially stretching in the temperature range of ₁ ) or less and slightly higher than the glass transition temperature Tg.

In the injection blow molding, a test tubular bottomed parison (preform) is injection-molded by injection molding, and this parison is blow-molded in a supercooled state or at a glass transition point Tg or higher. After parison injection molding,
In the hot parison method, the temperature is adjusted to a temperature not higher than the melting point Tm and blow molding is performed without solidification. On the other hand, after the parison was injection-molded, the parison was once cooled and solidified, and then Tg
The cold parison method is to reheat, adjust the temperature, and perform blow molding.

The hot parison method includes stretch blow molding and unstretch blow molding, but the cold parison method is usually only stretch blow molding. In injection blow molding, a thermoplastic resin material containing polyglycolic acid, at least one thermoplastic resin, and optionally an adhesive by co-injection (coinjection) method,
A preform is molded and then blow molded by a hot parison method or a cold parison method. At this time,
Stretch blow molding or non-stretch blow molding is performed. The injection temperature is preferably in the range of the melting point Tm of polyglycolic acid to 255 ° C. If the injection temperature is too high, the polyglycolic acid is likely to decompose.

The multi-layer hollow container of the present invention is used, for example, as a hollow container for beverages and foods, a container for toiletries, a container for gasoline by utilizing its excellent oxygen gas barrier property and / or carbon dioxide gas barrier property. . In particular, the use of packaging containers such as retort sterilized products that require high temperature and high humidity treatment, products that require special long-term storage, products that require carbon dioxide gas barrier properties, and products that require reduced environmental impact. It is preferably used for.

8. Multi-Layer Film The multi-layer film of the present invention comprises at least one layer of a thermoplastic resin film (hereinafter, sometimes referred to as “base film”) layer and a film layer made of a thermoplastic resin material containing polyglycolic acid (hereinafter, “ PGA layer "). The presence of the PGA layer makes it possible to obtain a multilayer film having excellent gas barrier properties. If necessary, an adhesive layer can be interposed between the layers. The total thickness of the multilayer film is
It is usually 2 μm to 3 mm, preferably 5 μm to 2 mm, more preferably 10 μm to 1 mm. If the thickness is too thin, it is difficult to manufacture, and the cost is high, which is not preferable from the viewpoint of productivity and economy. If this thickness is too thick, it is difficult to carry out the secondary processing for use as a packaging material, the cost is high, and it is not preferable from the viewpoint of productivity and economy.

The basic layer structure of the multilayer film of the present invention is as follows. However, the adhesive layer is omitted. Further, a thermoplastic resin material containing polyglycolic acid is abbreviated as PGA.

(1) Thermoplastic resin / PGA (2) Thermoplastic resin 1 / PGA / thermoplastic resin 1 (3) Thermoplastic resin 1 / PGA / thermoplastic resin 2

If the multilayer film of the present invention has the above-mentioned basic layer constitution, various thermoplastic resin films of the same kind or different kinds are additionally laminated according to various required characteristics. May be. Thermoplastic resin film and P
The method of compounding the GA layer is not particularly limited, and for example, a method is used in which each film is manufactured separately and then laminated, a method in which one resin is extrusion coated with another resin, and a method in which the films are laminated by a coextrusion method. Various laminating methods such as method can be adopted.

Examples of the thermoplastic resin film used in the present invention include ultra low density polyethylene (VLDP).
E), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MD
PE), high density polyethylene (HDPE), polypropylene (PP), ethylene-propylene rubber (EPM),
Ethylene / vinyl acetate copolymer (EVA), ethylene /
Acrylic ester copolymer (EEA), ionomer (IO) and other polyolefins; polyethylene terephthalate (PET), polyethylene naphthalate (PE
N) and other polyesters; polystyrene (PS), high-impact polystyrene (HIPS), styrene-butadiene-styrene-block copolymer (SBS), hydrogenated S
Polystyrene resin such as BS (that is, SEBS); polyvinyl chloride (PVC) resin such as hard polyvinyl chloride and soft polyvinyl chloride; polycarbonate (P
A film formed of a thermoplastic resin such as C), polyamide (PA), polyurethane (PU), ethylene / vinyl alcohol copolymer (EVOH), or polyvinylidene chloride resin (PVDC) is preferable.

As the thermoplastic resin film having a small environmental load, for example, a film formed of a biodegradable polymer such as polylactic acid, polysuccinic acid ester, polycaprolactone or the like is preferable. These thermoplastic resins may be modified resins. Specific examples thereof include LLDPE graft-modified with an acid such as acrylic acid.

In the multilayer film of the present invention, the thermoplastic resin film is used in a single layer or multiple layers. The thickness of the thermoplastic resin film is usually 1 μm to 2.5 mm, preferably 5 μm to 2 mm, more preferably 10 μm to 1
The range of mm is desirable from the viewpoints of workability and economy.

In the present invention, the thermoplastic resin film layer and P
An adhesive layer may be interposed between the layers in order to enhance the interlayer adhesion with the GA layer. The adhesive used in the adhesive layer, for example, carboxylated polyolefin,
Epoxidized polyolefin, ethylene / vinyl acetate copolymer, ionomer, polyurethane, epoxy resin, S
Examples thereof include polymers such as BS, SEBS, polychloroprene, styrene-butadiene copolymer rubber (SBR), and natural rubber (NR). The carboxylated polyolefin is a polyolefin in which a carboxyl group is introduced by modifying the polyolefin with an unsaturated acid monomer such as acrylic acid, methacrylic acid or maleic anhydride. The carboxyl group may be introduced by either a copolymerization method or a graft method.
Further, the above unsaturated acid monomer, methacrylic acid ester,
You may use together with vinyl type monomers, such as an acrylic ester and vinyl acetate.

The epoxidized polyolefin is a polyolefin in which an epoxy group is introduced by modifying the polyolefin with an epoxy group-containing monomer such as glycidyl methacrylate. The epoxy group may be introduced by either a copolymerization method or a graft method. Moreover, you may use together the said epoxy group containing monomer and vinyl type monomers, such as a methacrylic acid ester, an acrylic acid ester, and vinyl acetate. Among these, carboxylated polyolefin and ethylene-vinyl acetate copolymer are particularly preferable from the viewpoint of adhesiveness and processability. The thickness of the adhesive layer is usually 0.5 μm to 2 m.
m, preferably 2 μm to 1 mm, more preferably 3 μm
The range is from 0.5 mm. If the thickness is less than 0.5 μm, the adhesiveness may be insufficient and the application is difficult. If the thickness exceeds 2 mm, the cost is high and it is economically disadvantageous.

In the multilayer film of the present invention, a PGA layer is arranged as a gas barrier resin layer in order to improve the oxygen gas barrier property and / or carbon dioxide gas barrier property of the thermoplastic resin film. When a general thermoplastic resin film is used, both the oxygen gas barrier property and the carbon dioxide gas barrier property are improved.

When the multilayer film of the present invention is produced by a lamination method or an extrusion coating method,
Oriented films of PGA can be used. PGA
The oriented film can be produced by melt-extruding the above-mentioned netoresin of polyglycolic acid or the thermoplastic resin material containing the polyglycolic acid, stretching and orienting, and optionally heat-fixing. As the melt film forming method, a method such as uniaxial stretching by a flat die method, sequential biaxial stretching, simultaneous biaxial stretching, or inflation biaxial stretching by a circular die method can be adopted.

In the method for producing a multilayer film of the present invention, when only stretching / orientation is carried out and heat fixation is omitted, a multilayer film having a high heat shrinkage can be obtained.

The thickness of the PGA layer, which is the barrier property improving material of the multilayer film of the present invention, is usually 0.5 μm to 2 mm, preferably 1 μm to 1.5 mm. If the thickness is too thin, the effect of improving the barrier property may be insufficient, and if it is too thick, the quality may be too high, which is economically disadvantageous. If necessary, the thickness of the PGA layer is 5 μm
Hereinafter, even if the film thickness is extremely thin, such as about 1 to 3 μm, a layer having a uniform thickness can be formed.

The multilayer film of the present invention usually has an oxygen gas permeability and / or carbon dioxide gas permeability of 1/100 as compared with those of the thermoplastic resin film (base film).
2 or less, preferably 1/5 or less, more preferably 1 /
It can be improved to 10 or less. For example, polyolefin, polyester, polystyrene, polyvinyl chloride,
Polycarbonate, polylactic acid, polysuccinic acid ester,
Polycaprolactone, polyamide, EVOH, PVDC
At least one of oxygen gas permeability and carbon dioxide gas permeability is obtained by combining a PGA layer as a barrier property improver with a film made of a thermoplastic resin such as
A surprisingly improved multilayer film can be obtained as compared with the thermoplastic resin film. Moreover, the multi-layer film of the present invention has very little deterioration in its gas barrier property even when subjected to treatment under high temperature and high humidity.

The method for producing the gas barrier composite film of the present invention is roughly classified into the following methods.

Fusion method, lamination method (dry lamination, hot melt lamination, wet lamination, non-solvent lamination, etc.), extrusion coating method, coextrusion method (inflation method, T-die method, etc.).

In the fusion method, the thermoplastic resin film and PG are used.
The thermoplastic resin film (in the case of a multilayer film, the contact surface layer) in contact with the PGA film is roughly melted (Tm) by aligning each surface of the A film with each other and using a heat roll, a heat press, or the like. ) A composite can be obtained by pressing at the above temperature. At this time, PGA
It is desirable to subject the film surface to mechanical roughening treatment, activation treatment by a corona treatment method, activation treatment by a chemical agent, and the like. In this fusion method, for a thermoplastic resin film having a small polarity such as a polyolefin film,
The adhesive strength of the PGA film may be insufficient.

As the lamination method, the following method can be adopted. (1) Dry lamination method: A solution type, latex type, or dispersion type adhesive is applied to the surface of the thermoplastic resin film or the surface of the PGA film, the solvent is volatilized and dried, and then the mating film is combined. Then, it is pressure-bonded while being heated by a hot roll, a hot press or the like to obtain a multilayer film.

(2) Hot melt lamination method: A hot melt type adhesive (for example, EVA adhesive) is applied to the surface of the thermoplastic resin film or PGA film.
It is applied in the form of powder or film, and it is heated and pressure-bonded together with the surface of the mating film, and laminated. A method in which a hot-melt type adhesive is heated and melted and applied to the surface of one of the films, and then it is attached to the mating film by pressure bonding, or an adhesive film is inserted between the thermoplastic resin film and the PGA film. Then, a multilayer film can be obtained by a method of heating, pressure bonding and laminating.

In the extrusion coating method, the resin forming the thermoplastic resin film is supplied to an extruder equipped with a T-die, and while being melt-extruded from the T-die, on the surface of the PGA film or the surface of the multilayer film containing the PGA film layer,
A multi-layer film can be obtained by applying uniformly in a molten film state. In this case, it is possible to apply an adhesive layer on the surface of the PGA film.

In the co-extrusion method, a resin such as polyolefin, polyester, polystyrene, or polyvinyl chloride to be a thermoplastic resin film, a thermoplastic resin material containing polyglycolic acid as a barrier property improving material, and, if necessary, both The resin to serve as the adhesive of (1) is supplied from each extruder to one die, and is simultaneously extruded, and is laminated in a molten state to produce a multilayer film in one step. The co-extrusion method can be generally classified into a T-die method and an inflation method.

Typical T die methods include a laminar flow method using a single manifold die, an in-die laminating method using a multi-manifold die, and an outer die laminating method using a dual slot die. A resin to be a thermoplastic resin film, a thermoplastic resin material containing polyglycolic acid, and, if necessary, a resin to be an adhesive are supplied from each extruder to one die and coextruded and cast. A multi-layer film is produced by taking it out into a roll, stretching it in MD with a stretching roll or the like, stretching it in TD with a tenter or the like as necessary to form a film, and heat-fixing it if necessary. In general, the T-die method is preferable in the case of a thin film multilayer film having a thickness of 30 μm or less.

The inflation method is typified by an in-die laminating method (Robert-Colombo method, etc.) and an outside-die laminating method. A thermoplastic resin film, a thermoplastic resin material containing polyglycolic acid, and a resin to be used as an adhesive, if necessary, are supplied from each extruder to one die, and coextruded to form a tubular form. The film is formed into a film, pressed and pressed as necessary to form a flat film, and further heat-fixed as necessary to form a multilayer film.

The multilayer film of the present invention can be used, for example, for food packaging materials (meat, seafood, dairy products, pickles, miso, confectionery) by utilizing its excellent oxygen gas barrier property and / or carbon dioxide gas barrier property. , Packaging materials for tea / coffee, noodles, cooked rice, etc.), packaging materials for toiletries, chemical packaging materials, etc. In particular, it is preferably used as a packaging material for articles that require treatment under high temperature and high humidity such as retort sterilization, articles that require special long-term storage, and articles that require reduction of environmental load.

[0143]

EXAMPLES The present invention will be described more specifically below with reference to synthesis examples, examples and comparative examples. The methods for measuring physical properties are as follows.

(1) Melt viscosity η *: As a sample, an amorphous sheet having a thickness of about 0.2 mm was prepared from polyglycolic acid in a molded product, and heated at about 150 ° C. for 5 minutes to be crystallized. Using a capillograph equipped with a nozzle having D = 0.5 mm and L = 5 mm (manufactured by Toyo Seiki Co., Ltd.), the melt viscosity was measured at a melting point Tm of the polymer + 20 ° C. and a shear rate of 100 / sec.

(2) Thermal properties of polymer: As a sample,
An amorphous sheet having a thickness of about 0.2 mm was prepared from the polyglycolic acid in the molded product, and the differential scanning calorimeter (DSC; Mett) was used.
The crystallization temperature (Tc) was obtained by using a TC-10A type manufactured by Ler Co., Ltd. under a nitrogen gas stream at a heating rate of 10 ° C./min.
₁ ), melting point (Tm), and enthalpy of fusion (ΔHm)
Was measured. The glass transition temperature (Tg) was measured at a temperature rising rate of 5 ° C / min.

(3) Density of non-oriented crystallized product: As a sample, the thickness was about 0.2 mm from the polyglycolic acid in the molded product.
Of the amorphous sheet prepared in (1) above and heat-fixed at 150 ° C. for 5 minutes was used for measurement according to JIS R-7222 (Pycnometer method using n-butanol).

(4) Thickness: Regarding the thickness of the polyglycolic acid layer and the like, the thickness of 10 points of the sample was measured using a micrometer (μ-mate, manufactured by Sony Corporation), and the average value was obtained.

(5) Thickness Variation (R%) The thickness variation (R%) of the polyglycolic acid layer was calculated as a variation from the set thickness, and evaluated according to the following criteria according to the type of each molded product. Oriented film ⊚: R% is less than 10%, ◯: R% is 10% or more and less than 30%, Δ: R% is 30% or more and less than 70%, X: R% is 70% or more, and / or PGA. Breaking the film. Stretch blow container ⊚: R% is less than 10%, ◯: R% is 10% or more and less than 30%, Δ: R% is 30% or more and less than 70%, X: R% is 70% or more. Multilayer hollow container ◎: R% is less than 50%, ◯: R% is 50% or more and less than 100%, Δ: R% is 100% or more and less than 200%, ×: R% is 200% or more, and / or Not moldable. Multilayer film ⊚: R% is less than 50%, ◯: R% is 50% or more and less than 100%, Δ: R% is 100% or more and less than 200%, ×: R% is 200% or more.

(6) Soil disintegration test piece was buried in a soil of a field at a depth of about 10 cm, excavated after 6 months, washed, dried and weighed, and weighed relative to the initial weight of the test piece. The ratio (% by weight) was calculated.

[Synthesis Example 1] Synthesis of glycolide 5 kg of glycolic acid [manufactured by Wako Pure Chemical Industries, Ltd.] was charged into a 10-liter autoclave and stirred at 170 ° C.
To 200 ° C. for about 2 hours while heating and condensing while distilling generated water. Then, 20 kPa (2
The pressure was reduced to 00 mbar) and the pressure was maintained for 2 hours to distill out low-boiling components to prepare glycolic acid oligomers. The melting point Tm of the glycolic acid oligomer was 205 ° C.

1.2 kg of glycolic acid oligomer was added to 10
A liter flask was charged, and 5 kg of benzyl butyl phthalate as a solvent (manufactured by Junsei Chemical Co., Ltd.) and polypropylene glycol as a solubilizing agent (manufactured by Junsei Chemical Co., Ltd.,
# 400] Add 150 g, and in a nitrogen gas atmosphere, 5 kP
Under reduced pressure of a (50 mbar), the mixture was heated to about 270 ° C. to perform “solution phase depolymerization” of the glycolic acid oligomer, and the produced glycolide was co-distilled with benzylbutyl phthalate. Approximately twice the volume of cyclohexane was added to the obtained co-distillate to precipitate glycolide from benzylbutyl phthalate, which was then filtered off. This was recrystallized using ethyl acetate and dried under reduced pressure to obtain purified glycolide.

[Synthesis Example 2] Polyglycolic acid (PGA-a)
Synthesis of Glycolide 100 g, tin octoate 6 mg, and lauryl alcohol 50 mg were charged into a glass test tube, and 2
Polymerization was carried out at 20 ° C. for 3 hours. After the polymerization, after cooling, the produced polymer was taken out, pulverized, and washed with acetone. Then, the polymer was recovered by vacuum drying at 30 ° C. The same operation was repeated to synthesize the required amount of polyglycolic acid.

[Synthesis Example 3] Polyglycolic acid (PGA-b)
Toyo Seiki Co., Ltd. LT-20 with a synthetic 5 mm hole die
300 rpm with 15 rpm and a temperature setting of 200-240 ° C. (resin temperature 240 ° C.).
m tin tetrachloride pentahydrate was added and polymerization was carried out by charging from a hopper.

[Synthesis Example 4] Polyglycolic acid (PGA-c)
Synthesis of 100 g of glycolide and 4 mg of tin dichloride dihydrate,
Polymerization was performed in a glass test tube at 180 ° C. for 2 hours. At the end of the reaction, the polymer was solidified. After cooling, the polymer was taken out, pulverized, washed with acetone, and vacuum dried at 30 ° C. to obtain a polymer. The same operation was repeated to synthesize the required amount of polyglycolic acid.

[Example 1] Compression molded product The polyglycolic acid (PGA-a) obtained in Synthesis Example 2 was mixed with 3 mm.
It was supplied to a small twin-screw kneader equipped with a φ nozzle under a nitrogen gas flow, extruded in a strand shape at a melting temperature of about 230 to 240 ° C., air-cooled and cut to obtain pellets. The pellets were supplied to a molding machine to form a sheet at a resin temperature of about 235 ° C. The sheet is compression-molded at a pressure of 40 kg · f / cm ^{2 at} a temperature of 100 ° C. for a time of 5 seconds, and a tray (3
0 mm, bottom 100 mm x 200 mm, thickness 500μ
m) was obtained.

With respect to the physical properties of polyglycolic acid in this molded product, the melt viscosity is 50 Pa · s, the crystallization temperature (Tc ₁ ) is 84 ° C., the melting point (Tm) is 222 ° C., and the enthalpy of fusion (ΔHm) is 74 J / g. , Glass transition temperature (Tg) is 3
At 8 ° C., the density of the non-oriented crystallized product was 1.58 g / cm ³ . Using this molded product as a test piece, a soil disintegration test was conducted. The results are shown in Table 1.

[Example 2] Same as Example 1 except that the polyglycolic acid (PGA-b) obtained in Synthesis Example 3 was used in place of the polyglycolic acid (PGA-a) of the compression molded product. Then, a tray was prepared. Regarding the physical properties of polyglycolic acid in this molded product, the melt viscosity is 300 Pa · s,
Crystallization temperature (Tc ₁ ) is 85 ° C., melting point (Tm) is 222.
C., the melting enthalpy (ΔHm) was 75 J / g, the glass transition temperature (Tg) was 38 ° C., and the density of the non-oriented crystallized product was 1.58 g / cm ³ . Using this molded product as a test piece, a soil disintegration test was conducted. The results are shown in Table 1.
Shown in.

[Comparative Example 1] The same as Example 1 except that the polyglycolic acid (PGA-c) obtained in Synthesis Example 4 was used in place of the polyglycolic acid (PGA-a) of the compression molded product. Then, a tray was prepared. Regarding the physical properties of polyglycolic acid in this molded product, the melt viscosity is 800 Pa · s,
Crystallization temperature (Tc ₁ ) 86 ° C, melting point (Tm) 222
C., the melting enthalpy (ΔHm) was 75 J / g, the glass transition temperature (Tg) was 38 ° C., and the density of the non-oriented crystallized product was 1.58 g / cm ³ . Using this molded product as a test piece, a soil disintegration test was conducted. The results are shown in Table 1.
Shown in.

[Comparative Example 2] The same as Example 1 except that polyethylene terephthalate (PET; J135 manufactured by Mitsui Pet Co., Ltd.), which is a thermoplastic polyester, was used instead of the compression molded product polyglycolic acid (PGA-a). Then, a tray was prepared and a soil disintegration test was conducted. The results are shown in Table 1.

[0160]

[Table 1]

As is clear from the results shown in Table 1, when the melt viscosity of polyglycolic acid is as low as less than 500 Pa · s (Examples 1 and 2), the soil disintegration proceeds extremely quickly, and the short-term It turns out that composting is possible.

[Example 3] Oriented film Polyglycolic acid (PGA-a) 100 obtained in Synthesis Example 2
0.1 parts by weight of alumina powder was added to parts by weight, and the mixture was supplied to a small twin-screw extruder equipped with a 3 mmφ nozzle under a nitrogen gas flow and extruded in a strand shape at a melting temperature of about 230 to about 235 ° C. , Quenched and cut to make pellets.

The pellets were supplied to a small twin-screw extruder equipped with an inflation ring die under a nitrogen gas stream and extruded from the ring die into a tube at a resin temperature of about 230 ° C. Then, the tube was rapidly cooled to Tg or lower by a cold bath, and blown at about 3 times and blown at 40 to 45 ° C. The take-up speed was controlled so that the longitudinal stretching ratio of the tube was about 3 times, and the tube was wound through a nip roll to prepare a tubular film.
This film was heat set at 150 ° C. for 1 minute to obtain a biaxially oriented film (stretching ratio 3 × 3, thickness 15 μm). Furthermore, the thickness is set to 2 by adjusting the blow ratio and the stretching ratio in the machine direction.
Biaxially oriented films of 5 μm and 40 μm were produced.

The melt viscosity of polyglycolic acid in these biaxially oriented films was 55 Pa · s. The variation R% from the set thickness of each biaxially oriented film was measured.
The measurement results are shown in Table 2.

[Example 4] Alignment film The same as Example 3 except that the polyglycolic acid (PGA-b) obtained in Synthesis Example 3 was used in place of the polyglycolic acid (PGA-a). Thicknesses of 15 μm, 25 μm and 4
A 0 μm biaxially oriented film was prepared. The melt viscosity of polyglycolic acid in these biaxially oriented films is 310.
It was Pa · s. The variation R% from the set thickness of each biaxially oriented film was measured. The measurement results are shown in Table 2.

Comparative Example 3 The same as Example 3 except that the polyglycolic acid (PGA-c) obtained in Synthesis Example 4 was used in place of the oriented film polyglycolic acid (PGA-a). Thicknesses of 15 μm, 25 μm and 4
A 0 μm biaxially oriented film was prepared. The melt viscosity of polyglycolic acid in these biaxially oriented films is 820.
It was Pa · s. The variation R% from the set thickness of each biaxially oriented film was measured. The measurement results are shown in Table 2.

[0167]

[Table 2]

As is clear from the results shown in Table 2, when the melt viscosity of polyglycolic acid is as low as less than 500 Pa · s (Examples 3 to 4), it is 40 μm or less, more preferably 15 to
Even if it is as thin as 25 μm, it is possible to obtain an oriented film with a small variation from the set thickness.

Example 5 Stretching Blow Container 3 g of the polyglycolic acid (PGA-a) obtained in Synthesis Example 2 was used.
It was supplied to a small twin-screw kneading extruder equipped with a mφ nozzle under a nitrogen gas flow, melt-extruded in strands at a melting temperature of about 230 to 240 ° C., air-cooled and cut to obtain pellets. These pellets are supplied to an injection molding machine and injected (injected) into a bottomed parison mold (temperature of about 10 ° C) at a resin temperature of about 230 ° C, solidified and taken out, and a preform made of cold parison (thickness about 1.6 mm, outer diameter of about 1.6
cm, length about 5 cm, bottom spherical surface) was preformed. The obtained cold preform is preheated to about 42 ° C. to be softened, and a stretching rod is inserted to stretch and orient about 2.25 times in the longitudinal direction, and at the same time, the outer diameter of the trunk is about 4.5 cm, and the length of the trunk is about 4.5 cm. 9 cm, neck outer diameter about 1.6 cm, neck length about 1 cm, flat bottom center concave bottle with two split molds, blow with high pressure gas at a blow ratio of about 2.8, circumferential direction (lateral direction) ) Is stretched and oriented to form a bottle, and a high-pressure gas is blown into the bottle to heat-set the bottle at 150 ° C. for 10 seconds,
It was taken out of the mold and a stretch blow container was molded.

The stretch-blow container obtained was transparent. By adjusting the blow ratio and the stretching ratio in the machine direction, each stretch blow container having a body portion thickness of 50 μm, 100 μm, and 200 μm was prepared. The melt viscosity of polyglycolic acid in these stretch-blown containers was 45 Pa · s. In addition, the variation R% from the set thickness of the body portion of these stretch blow containers was measured. The results are shown in Table 3.

Example 6 Similar to Example 5 except that the polyglycolic acid (PGA-b) obtained in Synthesis Example 3 was used in place of the polyglycolic acid (PGA-a) in the stretch blow container. And the body thickness is 50μm, 100μ
m and 200 .mu.m stretch blow containers were produced. The melt viscosity of polyglycolic acid in these stretch-blown containers was 290 Pa · s. In addition, the variation R% from the set thickness of the body portion of these stretch blow containers was measured. The results are shown in Table 3.

Comparative Example 4 Same as Example 5 except that the polyglycolic acid (PGA-c) obtained in Synthesis Example 4 was used in place of the polyglycolic acid (PGA-a) in the stretch blow container. And the body thickness is 50μm, 100μ
m and 200 .mu.m stretch blow containers were produced. The melt viscosity of polyglycolic acid in these stretch-blown containers was 780 Pa · s. In addition, the variation R% from the set thickness of the body portion of these stretch blow containers was measured. The results are shown in Table 3.

[0173]

[Table 3]

As is clear from the results shown in Table 3, when the melt viscosity of polyglycolic acid is as low as less than 500 Pa · s (Examples 5 to 6), the thickness of the body portion is 200 μm or less, further 50 to 100 μm. And even if thin
It is possible to obtain a stretch-blown container with a small variation from the set thickness.

Example 7 Multilayer Hollow Container 3 g of polyglycolic acid (PGA-a) obtained in Synthesis Example 2 was used.
It was supplied to a small twin-screw kneading extruder equipped with a mφ nozzle under a nitrogen gas flow, melt-extruded in strands at a melting temperature of about 230 to 240 ° C., air-cooled and cut to obtain pellets. This pellet, polyethylene terephthalate (PE
T; M135 PET J135), and carboxylated polyolefin (registered trademark MODED E-300S)
Was supplied to a co-injection molding machine for 3 types and 5 layers, and was injected and injected into a preform die to form a preform (outer diameter of about 2 cm, length of about 6 cm), which was cooled and solidified. Then, the preform is reheated, adjusted to a temperature of about 85 ° C., inserted into a mold, a rod is inserted into the preform, and the preform is stretched about 2 times in the longitudinal direction and blown at the same time. Blow at a ratio of about 3 and then solidify by cooling to PET // PGA
// A multilayer hollow container having a PET layer structure was prepared.

By adjusting the draw ratio and blow ratio, the P of the core layer is adjusted.
Each multi-layer hollow container having a GA layer thickness of 3 μm, 5 μm, and 10 μm was produced. The melt viscosity of polyglycolic acid in the PGA layer of these multilayer containers was 50 Pa · s. The variation R% from the set thickness of the body core layer of these multilayer hollow containers was measured. The results are shown in Table 4.

Example 8 Similar to Example 7 except that the polyglycolic acid (PGA-b) obtained in Synthesis Example 3 was used in place of the polyglycolic acid (PGA-a) in the multilayer hollow container. And the thickness of the PGA layer of the core layer is 3 μm,
5 μm and 10 μm multi-layer hollow containers were produced. The melt viscosity of polyglycolic acid in the PGA layer of these multilayer containers was 300 Pa · s. The variation R% from the set thickness of the body core layer of these multilayer hollow containers was measured. The results are shown in Table 4.

[Comparative Example 5] The same as Example 7 except that the polyglycolic acid (PGA-c) obtained in Synthesis Example 3 was used in place of the polyglycolic acid (PGA-a) in the multilayer hollow container. And the thickness of the PGA layer of the core layer is 3 μm,
5 μm and 10 μm multi-layer hollow containers were produced. The melt viscosity of the polyglycolic acid in the PGA layer of these multilayer containers was 800 Pa · s. The variation R% from the set thickness of the body core layer of these multilayer hollow containers was measured. The results are shown in Table 4.

[0179]

[Table 4]

As is clear from the results shown in Table 4, when the melt viscosity of polyglycolic acid is as low as less than 500 Pa · s (Examples 7 to 8), the body core layer has a thickness of 10 μm or less, more preferably 3 μm or less. Even if it is extremely thin, ~ 5 μm,
It is possible to obtain a multilayer hollow container having a small variation from the set thickness.

Example 9 Multilayer Film The polyglycolic acid (PGA-a) obtained in Synthesis Example 2 was used in an amount of 3 m.
It was supplied to a small twin-screw kneading extruder equipped with a mφ nozzle under a nitrogen gas flow, melt-extruded in strands at a melting temperature of about 230 to 240 ° C., air-cooled and cut to obtain pellets.

[0182] This pellet and acid-modified LLDPE (Admer NF550 manufactured by Mitsui Chemicals; acid-grafted LLDPE)
Are extruded from each extruder at a resin temperature of about 230 ° C., and three layers are formed in the feed block (acid-modified LLDP
E / PGA / acid-modified LLDPE). Dice is 30
cm width, and the inner layer acid-modified LLDPE is 3
With a 5mmφ extruder, the acid-modified LLDPE of the outer layer is 40m
The core layer PGA was extruded by a 25 mmφ extruder to form a film by an mφ extruder.

The extrusion amount of the core layer was adjusted to prepare multilayer films having core layers with thicknesses of 1 μm, 3 μm, and 5 μm, respectively. The melt viscosity of polyglycolic acid in the PGA layer of these multilayer films was 55 Pa · s. Variation R% from the set thickness of the core layer of these multilayer films
Was measured. The results are shown in Table 5.

[Example 10] Multilayer film The same as Example 9 except that the polyglycolic acid (PGA-b) obtained in Synthesis Example 3 was used in place of the polyglycolic acid (PGA-a). And the core layer has a thickness of 1 μm and 3 respectively.
μm and 5 μm multilayer films were prepared. The melt viscosity of polyglycolic acid in the PGA layer of these multilayer films was 310 Pa · s. The variation R% from the set thickness of the core layer of these multilayer films was measured. The results are shown in Table 5.

[Comparative Example 6] The same procedure as in Example 9 except that the polyglycolic acid (PGA-c) obtained in Synthesis Example 4 was used in place of the polyglycolic acid (PGA-a) in the multilayer film. And the core layer has a thickness of 1 μm and 3 respectively.
μm and 5 μm multilayer films were prepared. The melt viscosity of polyglycolic acid in the PGA layer of these multilayer films was 820 Pa · s. The variation R% from the set thickness of the core layer of these multilayer films was measured. The results are shown in Table 5.

[0186]

[Table 5]

As is clear from the results shown in Table 5, when the melt viscosity of polyglycolic acid is as low as less than 500 Pa · s (Examples 9 to 10), the thickness of the core layer is 5 μm or less, further 1 to 3 μm. Even if it is extremely thin, it is possible to obtain a multilayer film with a small variation from the set thickness.

[0188]

EFFECTS OF THE INVENTION According to the present invention, it contains polyglycolic acid which has excellent fluidity in a molten state, can form a uniform thin film, has outstanding biodegradability, and can be rapidly composted. Extruded product formed using a thermoplastic resin material, oriented film, stretch blow container, multilayer hollow container,
Various molded products such as multilayer films are provided.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29K 67:00 B29L 22:00 B29L 22:00 C08L 67:04 C08L 67:04 B65D 1/00 B F-term (reference) 3E033 AA01 BA30 CA03 CA07 CA16 CA20 FA02 FA03 4F071 AA43 AA88 AF52 BA01 BB03 BB06 BB07 4F100 AK01B AK54A AK54K BA02 GB16 JA04A JA06A JA20A JB16B JL01 4F208 AA24 AG07 AH55 AM32 LA04 LB01 4J029 AA02 AB01 AC01 AC02 AD01 AE01 AE03 EA03 EA05 EH02 KE05 KE09

Claims (6)

[Claims] 1. The following formula (1): Which is a molded product containing polyglycolic acid as a main component and containing 60% by weight or more of the repeating unit represented by the formula (1), wherein the melt viscosity of the polyglycolic acid in the molded product is 20 ° C from the melting point.
When measured under conditions of high temperature and shear rate of 100 / sec,
A molded product of 20 Pa · s or more and less than 500 Pa · s. 2. The following formula (1): An oriented film containing polyglycolic acid as a main component, containing 60% by weight or more of the repeating unit represented by
An oriented film in which the melt viscosity of polyglycolic acid in the oriented film is 20 Pa · s or more and less than 500 Pa · s when measured at a temperature 20 ° C. higher than the melting point and a shear rate of 100 / sec. 3. The following formula (1): A stretch-blowing container mainly comprising polyglycolic acid containing 60% by weight or more of the repeating unit represented by the formula (1), wherein the melt viscosity of the polyglycolic acid in the stretch-blowing container is 20 ° C. higher than the melting point and the shear rate is A stretch-blowing container having a viscosity of 20 Pa · s or more and less than 500 Pa · s when measured under the condition of 100 / sec. 4. The following formula (1): A multilayer molded article having a layer structure in which a thermoplastic resin layer is formed on at least one surface of a layer containing polyglycolic acid as a main component containing 60% by weight or more of the repeating unit represented by When the melt viscosity of the polyglycolic acid in the component layer is measured at a temperature 20 ° C. higher than the melting point and a shear rate of 100 / sec, it is 20 Pa.
A multi-layer molded product of s or more and less than 500 Pa · s. 5. The following formula (1): A multilayer hollow container having a layer structure in which a thermoplastic resin layer is formed on at least one surface of a layer containing polyglycolic acid as a main component containing 60% by weight or more of the repeating unit represented by The melt viscosity of the polyglycolic acid in the component layer is 20 Pa when measured at a temperature 20 ° C. higher than the melting point and a shear rate of 100 / sec.
A multi-layer hollow container of s or more and less than 500 Pa · s. 6. The following formula (1): A multilayer film having a layer structure in which a thermoplastic resin layer is formed on at least one surface of a layer containing polyglycolic acid as a main component containing 60% by weight or more of the repeating unit represented by The melt viscosity of polyglycolic acid in the layer is 20 Pa when measured at a temperature 20 ° C. higher than the melting point and a shear rate of 100 / sec.
A multilayer film having a thickness of s or more and less than 500 Pa · s.