WO2021049637A1 - Biodegradable laminated sheet, sheet for forming containers, and biodegradable container - Google Patents

Abstract

The present invention pertains to a biodegradable laminated sheet having a gas barrier layer. The present invention aims to form a sheet having uniform thickness of the gas barrier layer and provide excellent thermal resistance, even for comparatively deep containers. Provided is a biodegradable resin sheet having a surface layer, an intermediate layer, and a rear surface layer. The surface layer and the rear surface layer are biodegradable resin layers and the intermediate layer is a gas barrier layer. The indentation elastic modulus of the surface layer is greater than the indentation elastic modulus of the rear surface layer.

Description

Biodegradable laminated sheet, container forming sheet and biodegradable container

The present invention relates to a biodegradable laminated sheet, a container forming sheet, and a biodegradable container which have biodegradability, gas barrier property, and can be molded even in a container having a relatively deep bottom.

Due to the recent problems of plastic disposal, biodegradable plastic sheets are being developed.
Materials for biodegradable plastic sheets, that is, biodegradable resins include, for example, polylactic acid (also referred to as "PLA"), polycaprolactone (PCL), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and the like. Examples thereof include aliphatic polyesters, aromatic aliphatic polyesters such as polybutylene adipate terephthalate (PBAT), and polyvinyl alcohol (PVA) -based resins.

In general, there are many packaging containers for foods, pharmaceuticals, electronic / electrical parts, various industrial products, etc. that require gas barrier properties (for example, oxygen resistance and water vapor permeability). Therefore, the development of biodegradable plastic sheets or containers provided with a gas barrier layer is underway. Here, the "gas barrier" means, in a broad sense, suppression of permeation of arbitrary gas, and more specifically, suppression of permeation of oxygen and / or fragrance.

Conventionally, the "gas barrier layer" in a biodegradable plastic sheet or container is often made of a PVA-based resin containing a polymer or a copolymer containing a vinyl alcohol component as a main component resin.
In the biodegradable sheet and the container, by selecting the optimum PVA-based resin as the main component resin and forming the gas barrier layer, it is possible to impart excellent barrier properties while maintaining the secondary molding processability. Further, since the PVA-based resin has biodegradability, if it is used for the gas barrier layer, the entire sheet will have biodegradability. Therefore, the sheet and the container obtained from the sheet can be completely decomposed (no residue remains after biodegradation).

For example, in Patent Document 1, as a laminate having heat resistance and biodegrading after use, polybutylene succi is used as an adhesive layer between an aliphatic polyester resin layer made of polylactic acid and a polyvinyl alcohol resin layer. A biodegradable laminate using a modified polyester resin obtained by graft-modifying nate (hereinafter sometimes referred to as PBS) or polybutylene adipate terephthalate (hereinafter sometimes referred to as PBAT) with maleic anhydride has been disclosed. There is.
Patent Document 2 discloses a laminated sheet in which a polylactic acid resin layer and a barrier layer made of an ethylene-vinyl alcohol copolymer are bonded using a modified polyolefin resin.

International Publication No. 2013/069726 International Publication No. 2017/069127

When a container is produced by molding a biodegradable sheet provided with a gas barrier layer made of a PVA-based resin, it is necessary to make the thickness of the gas barrier layer uniform in order to secure the gas barrier property.
Conventionally, when a laminated sheet is produced by laminating a gas barrier layer on a biodegradable resin layer and the laminated sheet is thermoformed into a container, if the thickness of the entire laminated sheet can be uniformly controlled, the thickness of the gas barrier layer existing inside can be controlled. Was also thought to be able to be uniform.
However, it has been found that even if the thickness of the entire laminated sheet is controlled to be uniform, the thickness of the gas barrier layer may not be uniform and the gas barrier property may not be improved.

An object of the present invention is a new biodegradable laminated sheet having a gas barrier layer, which can form a sheet with a uniform thickness of the gas barrier layer even in a container having a relatively deep bottom and has excellent heat resistance. It is an object of the present invention to provide a container-forming sheet and a container made by using the same.

The biodegradable resin sheet according to one aspect of the present invention has a surface layer, an intermediate layer and a back layer, the surface layer and the back layer are biodegradable resin layers, the intermediate layer is a gas barrier layer, and the surface layer. The indentation elastic modulus of the back layer is higher than the indentation elastic modulus of the back layer.

The biodegradable resin sheet according to another aspect of the present invention has a configuration having a biodegradable resin layer and a gas barrier layer, the storage elastic modulus of the sheet at 110 ° C. is E'(110), and the sheet at 130 ° C. When the storage elastic modulus of is E'(130), the E'(110) is 5 MPa to 100 MPa, and a represented by the following formula (1) is -0.2 to -9.0 ×. It is 10 ^-4.

The container-forming sheet according to one aspect of the present invention comprises the above-mentioned biodegradable resin sheet.
Further, the biodegradable container according to one aspect of the present invention is formed by molding the above-mentioned container forming sheet.

The biodegradable container according to another aspect of the present invention is a biodegradable container provided with a side wall portion and a bottom surface portion, and the side wall portion and the bottom surface portion have a surface layer, an intermediate layer and a back layer. The surface layer and the back layer are biodegradable resin layers, the intermediate layer is a gas barrier layer, and the indentation elastic modulus of the surface layer is higher than the indentation elastic modulus of the back layer.

In the biodegradable laminated sheet and the biodegradable container according to the present invention, the surface layer having a high indentation elastic modulus contributes to heat resistance and the back layer having a low indentation elastic modulus contributes to moldability. For example, by setting the surface layer on the outside of the container and the back layer on the inside of the container, the secondary molding processability is excellent, and the thickness of the gas barrier layer can be uniformly molded even in a container with a relatively deep bottom. Not only is it excellent in heat resistance.
Here, the "secondary molding process" means a process of deforming a sheet into another shape or imparting another shape, and the processing method includes a thermoforming method such as vacuum forming or compressed air forming. Can be mentioned. However, it is not limited to these.

It is a vertical sectional view of the container which concerns on an example of the Example of this invention.

Next, the present invention will be described based on examples of embodiments of the invention. However, the present invention is not limited to the embodiments described below.

<<< This laminated sheet >>>
The biodegradable laminated sheet (referred to as "the present laminated sheet 1") according to an example of the embodiment of the present invention has a surface layer, an intermediate layer and a back layer, and the surface layer and the back layer are biodegradable resin layers. The intermediate layer is a gas barrier layer and is a biodegradable laminated sheet.

Further, the biodegradable laminated sheet (referred to as "the present laminated sheet 2") according to another example of the embodiment of the present invention has a biodegradable resin layer and a gas barrier layer, and has biodegradability. It is a laminated sheet.

The laminated sheets 1 and 2 may be a non-stretched sheet or a stretched sheet (stretched film). From the viewpoint of secondary molding processability, a non-stretched sheet is preferable.

In the present invention, the "biodegradable resin layer" means a layer containing a biodegradable resin as a main component resin, and the "gas barrier layer" means a layer having a gas barrier property.
In the present invention, "biodegradable" refers to the property of being finally decomposed into water and carbon dioxide by the action of microorganisms, and is preferably a pilot under an aerobic composting environment of 58 ° C. described in ISO16929 or JIS K6952. On a scale, a 100 mm square film has a property of satisfying that the remaining 10% of a 2 mm flue is within 12 weeks.
In the present invention, the "gas barrier property" means a property of suppressing the permeation of an arbitrary gas in a broad sense, and more specifically, a property of suppressing the permeation of oxygen and / or aroma. Preferably, the property satisfies that the oxygen permeability at 0 ° C. and / or room temperature (20 to 25 ° C.) and 50% RH is 5.0 cc / m ² · day · atm or less.

<< This Laminated Sheet 1 >>
First, the present laminated sheet 1 will be described.

<Surface and back layers>
The surface layer and the back layer (hereinafter, also referred to as “front and back layers”) in the laminated sheet 1 are biodegradable resin layers, and can be formed from a biodegradable resin composition.
The surface layer and the back layer may have the same composition or different compositions.

(Indentation modulus)
When the surface layer and the back layer of the laminated sheet 1 are formed of a container using the laminated sheet 1, assuming that the surface layer side is the outside of the container and the back layer side is the inside of the container, the indentation elastic modulus of the surface layer is assumed. Is higher than the indentation elastic modulus of the back layer. By making the indentation elastic modulus of the surface layer on the outside of the container higher than the indentation elastic modulus of the back layer on the inside of the container, it is possible to improve the secondary molding processability in the back layer while providing heat resistance and strength in the surface layer. The thickness of the gas barrier layer can be uniformly formed, and the heat sealability can be improved inside the container.
From this point of view, the difference in indentation elastic modulus between the surface layer and the back layer is more preferably 10 MPa or more, further preferably 100 MPa or more, of which 200 MPa or more, of which 500 MPa or more, and of which 1000 MPa or more. Is even more preferable.

The surface layer and the back layer of the laminated sheet 1 preferably have an indentation elastic modulus of at least one of them, that is, one or both layers of 100 MPa to 8000 MPa.
When the indentation elastic modulus of at least one of the surface layer and the back layer is 100 MPa to 8000 MPa, the handleability of the molded product of the laminated sheet 1 is improved.
From this point of view, the indentation elastic modulus of at least one of the surface layer and the back layer is preferably 100 MPa to 8000 MPa, more preferably 200 MPa or more or 7,000 MPa or less, and more preferably 300 MPa or more or 6000 MPa or less.

In addition, the indentation elastic modulus of the surface layer is made higher than the indentation elastic modulus of the back layer, the surface layer has heat resistance and strength, the back layer has good secondary molding processability, and the inside of the container has good heat sealability. The indentation elastic modulus of the surface layer of the laminated sheet 1 is preferably 500 MPa to 8000 MPa, particularly 1000 MPa or more or 7,000 MPa or less, particularly 1500 MPa or more or 6000 MPa or less, and more preferably 2000 MPa or more.
On the other hand, the indentation elastic modulus of the back layer is preferably 100 MPa to 3000 MPa, particularly preferably 1000 MPa or less, and further preferably 500 MPa or less.

As a method for measuring the indentation elastic modulus, the elasticity measured by a triangular pyramidal indenter (made of diamond, inter-weight angle 115 °) using a Shimadzu dynamic ultra-micro hardness meter (manufactured by Shimadzu Corporation, DUH-W201). A method of measuring the rate (pushing elastic modulus) can be mentioned.
The test mode is a load-unloading test, in which the triangular pyramid indenter is held for 5 seconds under the load when it reaches a depth of 10 μm from the surface of the sample, and then the load is removed and the depth of the triangular pyramid indenter is changed over time. Obtain the unloading curve.
_{Approximation using the maximum value (h max} ) of the depth of the triangular pyramid indenter in the loading process of the above test and the data of the unloading curve at 70% or more of the maximum test force among the unloading curves obtained in the above test. from the slope of the line (S), and the depth at the point of intersection with the approximate straight line and the x-axis (h _r), it is possible to calculate the modulus of elasticity using the following equation.
By using the ultrafine hardness tester, it is possible to measure the indentation elastic modulus of each of the surface layer or the back layer of the laminated sheet 1 and the container described later.

(Storage modulus)
The surface layer and the back layer of the laminated sheet 1 preferably have a storage elastic modulus of at least one, that is, one or both layers at 110 ° C. of 5 MPa to 100 MPa.
Here, 110 ° C. is a temperature assuming a heating temperature at the time of molding.
Further, it is considered that 110 ° C. exists in the most suitable temperature range for uniformly molding the gas barrier layer. Therefore, since it is rational to judge by the storage elastic modulus of about 110 ° C., the judgment was made by the storage elastic modulus at 110 ° C.
In the examples described later, the set temperature during the secondary molding process is 160 ° C. In the secondary molding process, the temperature rise and deformation occur at the same time, and the temperature rise rate is as high as 160 ° C / min. Therefore, the actual sheet temperature during the secondary molding process is higher than 160 ° C. Should also be considered low.
When the storage elastic modulus at at least one of the surface layer and the back layer at 110 ° C. is 5 MPa to 100 MPa, the surface layer and the back layer can be suitably molded even at around 110 ° C.
From this point of view, the storage elastic modulus of at least one of the surface layer and the back layer at 110 ° C. is preferably 5 MPa to 100 MPa, more preferably 7 MPa or more or 95 MPa or less, and more preferably 10 MPa or more or 90 MPa or less.

As described above, it has been found that even if the thickness of the entire laminated sheet is controlled to be uniform, the thickness of the gas barrier layer may not be uniform and the gas barrier property may not be improved. This is because the resin constituting the gas barrier layer is often easier to flow at a high temperature than the resin constituting the biodegradable resin layer, and the laminated sheet itself can be molded relatively uniformly. Even under a certain temperature condition, it is considered that the gas barrier layer tends to flow easily at that temperature and the thickness unevenness becomes large.
Therefore, as described above, by defining the storage elastic modulus of at least one of the surface layer and the back layer at 110 ° C., which is the most suitable temperature for uniformly molding the gas barrier layer, within a predetermined range, the gas barrier layer can also be formed. The surface layer and the back layer can also be molded suitably, and the secondary molding processability is excellent. Not only can the thickness of the gas barrier layer be uniformly molded even in a container with a relatively deep bottom, but also heat resistance. Can also be excellent.

As a method for measuring the storage elastic modulus, a dynamic viscoelasticity measuring device (“DVA-200” manufactured by IT Measurement Control Co., Ltd.) is used, and a tensile jig is used to measure the measurement temperature at -100 to 250 ° C. and the frequency at 10 Hz. , A method of measuring at a heating rate of 3 ° C./min can be mentioned.

From the same viewpoint, the total storage elastic modulus of the front and back layers at 110 ° C. is preferably 5 MPa or more, more preferably 7 MPa or more, and even more preferably 10 MPa or more.
On the other hand, it is preferably 100 MPa or less, more preferably 95 MPa or less, and even more preferably 90 MPa or less.

The total storage elastic modulus of the front and back layers of the laminated sheet 1 is (the storage elastic modulus of the surface layer × the thickness ratio of the surface layer to the total thickness of the surface layer and the back layer) + (the storage elastic modulus of the back layer × the total thickness of the surface layer and the back layer). It can be obtained by the ratio of the thickness of the back layer to the thickness of the back layer. That is, the total storage elastic modulus of the front and back layers is calculated by the following formula from the storage elastic modulus of each of the surface layer and the back layer and the thickness of each of the surface layer and the back layer.
_{E a '= E 1' ×} (t 1 / t 1 + t 2) + E 2 '× (t 2 / t 1 + t 2)
(However, E _a ': total storage elastic modulus of the front and back layers, E ₁ ': storage elastic modulus of the surface layer, E ₂ ': storage elastic modulus of the back layer, t ₁ : thickness of the surface layer, t ₂ : thickness of the back layer Is.)
If the ratio of the thickness of the intermediate layer (gas barrier layer) to the surface layer and the back layer of the laminated sheet 1 is small, the influence of the intermediate layer on the storage elastic modulus of the entire laminated sheet 1 is not so large. Therefore, the total storage elastic modulus of the front and back layers is almost the same as the storage elastic modulus of the entire laminated sheet 1.

Further, from the viewpoint of secondary moldability, the temperature range of the region where the total storage elastic modulus of the front and back layers is 10 MPa to 100 MPa is preferably 5 ° C. or higher, particularly 7 ° C. or higher, and 10 ° C. or higher among them. It is more preferable to have.
Since 10 MPa to 100 MPa is considered to be the optimum storage elastic modulus for secondary molding, the temperature region showing the storage elastic modulus in this range can be assumed to be the molding processing temperature region.
Therefore, if this storage elastic modulus region can be obtained in a wider temperature range, secondary molding can be suitably performed even if there is a temperature fluctuation, which is preferable.

Further, in the present laminated sheet 1, the total storage elastic modulus of the front and back layers at 160 ° C. is preferably 90 MPa or less, particularly 80 MPa or less, particularly 50 MPa or less, and further preferably 20 MPa or less.
When the storage elastic modulus at 160 ° C. is 90 MPa or less, the molding of a container having a relatively deep bottom can be performed even better.

The storage elastic moduli of the surface layer and the back layer of the laminated sheet 1 may be the same or different.
For example, when this laminated sheet is molded into a capsule container shape as shown in FIG. 1, the storage elastic modulus of the surface layer on the outside of the container is higher than the storage elastic modulus of the back layer on the inside of the container. Then, it is preferable in that the sealing property after molding, the heat resistance, and the thickness of the gas barrier layer can be uniformly molded.
Regarding the storage elastic modulus of the surface layer and the back layer, the type of the main component resin constituting the surface layer and the back layer can be changed, the copolymerization component of the main component resin can be changed, the molecular weight of the main component resin can be changed, or the surface layer. And / or can be appropriately adjusted by including inorganic particles in the back layer.

(composition)
Both the surface layer and the back layer of the laminated sheet 1 are mainly composed of a biodegradable aliphatic polyester, a biodegradable aromatic polyester, a biodegradable aliphatic aromatic polyester, or a mixed resin composed of a combination of two or more of these. It is preferable that the layer contains as a main component resin, and more preferably, it is a layer containing a biodegradable aliphatic polyester, a biodegradable aliphatic aromatic polyester, or a mixed resin composed of a combination thereof as a main component resin.
Here, the "main component resin" means a resin having the highest content (mass%) among the resins constituting each layer of the surface layer or the back layer. The content of the main component resin in each layer is preferably 50% by mass or more, particularly 70% by mass or more, particularly 80% by mass or more, and particularly 90% by mass or more (100% by mass) of the resin constituting each layer. Including).

The surface layer and the back layer may have the same main component resin or different resins.
For example, one of the surface layer and the back layer can be a layer having more excellent moldability, and the other layer can be made into a layer having more excellent heat resistance. Above all, when the laminated sheet 1 is used as an oxygen-airtight packaging container, a food packaging container, etc., a container is formed because heat resistance is required on the outside of the container and heat sealability is required on the inside of the container. At this time, it is preferable that the surface layer on the outside of the container is a layer having more excellent heat resistance, and the back layer on the inside of the container is a layer having more excellent moldability.
However, the present invention is not limited to such an example.

When the container is formed by using the laminated sheet 1, the surface layer on the outside of the container is preferably biodegradable aliphatic polyester. Since many biodegradable aliphatic polyesters generally have a high storage elastic modulus at around 100 ° C., the surface layer on the outside of the container contains the biodegradable aliphatic polyester, so that the container is made of boiling water or the like. It becomes difficult to deform even when exposed to high temperatures.
On the other hand, the back layer on the inside of the container is preferably biodegradable aliphatic aromatic polyester. Most biodegradable aliphatic polyesters have a storage elastic modulus of 5 MPa to 100 MPa at around 110 ° C., which is the most suitable temperature for uniformly molding the gas barrier layer, so that the back layer inside the container is raw. By containing the degradable aliphatic aromatic polyester, the secondary molding processability is improved.

Examples of biodegradable aliphatic polyesters include polylactic acid (PLA), polycaprolactone (PCL), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate, polyethylene succinate (PES), and the like. Examples thereof include 3-hydroxybutyrate-co-3-hydroxyhexanoate polymer (PHBH).
Examples of the biodegradable aliphatic aromatic polyester include polybutylene adipate terephthalate (PBAT) and polybutylene succinate terephthalate (PBST).

As an example of the main component resin of the surface layer and the back layer, particularly as a preferable example of the main component resin of the surface layer, for example, polybutylene succinate (PBS) or butylene succinate obtained by copolymerizing polybutylene succinate with a copolymerization component. Examples thereof include a copolymer or a mixed resin of polybutylene succinate (PBS) and another biodegradable aliphatic polyester.

Polybutylene succinate (PBS) is a biodegradable resin having a melting point (Tm) close to that of polyethylene and mechanical properties.
Since polybutylene succinate (PBS) has a high storage elastic modulus at around 100 ° C., which is 100 MPa or more, the surface layer on the outside of the container contains biodegradable aliphatic polyester, so that the container becomes hot water or the like. It is preferable because it does not easily deform even when exposed.
Further, polybutylene succinate (PBS) has a melting point of around 110 ° C., and has a storage elastic modulus of 100 MPa or less at around 110 ° C., which is the most suitable temperature for uniformly molding the gas barrier layer. It is preferable because it does not interfere with the container molding of 1.

In the butylene succinate copolymer, examples of the copolymerization component copolymerizing with polybutylene succinate (PBS) include ε-caprolactone (CL), glycolide (GA), L-lactide (LLA), and terephthalic acid (TPA). ), Adipic acid, sebacic acid, ethylene glycol, diethylene glycol, hexanediol, pentaerythritol, 3-alkoxy-1,2-propanediol and the like.
For example, by using terephthalic acid copolymer polybutylene succinate, the melting point of the surface layer and the back layer or the entire laminated sheet is increased, thereby increasing the heat resistance of the container, that is, the molded product of the laminated sheet 1. Can be done.

Polylactic acid (PLA) is preferable as another biodegradable aliphatic polyester to be mixed with polybutylene succinate (PBS). Polylactic acid (PLA) has a high storage elastic modulus at around 100 ° C. of 100 MPa or more, and has a high tensile strength at around 110 ° C., which is the most suitable temperature for uniformly molding the gas barrier layer. Therefore, the container is not easily deformed even when exposed to a high temperature such as boiling water, and the secondary molding processability is also good.

On the other hand, as a particularly preferable example of the main component resin of the back layer, for example, polybutylene adipate terephthalate (PBAT) can be mentioned.
Polybutylene adipate terephthalate (PBAT) has a storage elastic modulus of 5 MPa to 100 MPa at around 110 ° C., which is the most suitable temperature for uniformly molding the gas barrier layer. Therefore, when the back layer contains polybutylene adipate terephthalate (PBAT), the secondary molding processability is improved.

At least one of the surface layer and the back layer preferably contains inorganic particles.
By containing the inorganic particles, not only the storage elastic modulus can be increased, but also the heat resistance can be enhanced. In particular, it is preferable to include inorganic particles in the back layer inside the container when the container is formed, because the heat resistance and rigidity can be improved while improving the secondary molding processability. However, if the amount is too large, it will be difficult to stretch during molding.
From this point of view, the content of the inorganic particles should be 10 parts by mass or more with respect to the total amount of the compositions forming each layer, for example, 100 parts by mass of the total of the biodegradable resin and the inorganic particles, from the viewpoint of heat resistance. Is preferable, and more preferably 20 parts by mass or more, and more preferably 25 parts by mass or more. On the other hand, from the viewpoint of stretchability, it is preferably 60 parts by mass or less with respect to the total amount of the composition forming each layer, for example, 100 parts by mass of the total of biodegradable resin and inorganic particles, and more than 50 parts by mass. Among them, it is more preferably 40 parts by mass or less.

By containing inorganic particles in one or both of the front layer and the back layer, the storage elastic modulus of the laminated sheet can be increased, and the heat resistance and rigidity of the laminated sheet can be increased.

The type of the inorganic particles is not particularly limited. For example, silica, mica, talc, mica, clay, titanium oxide, calcium carbonate, diatomaceous soil, allofen, bentonite, potassium titanate, zeolite, sepiolite, smectite, kaolin, kaolinite, glass, limestone, carbon, wallastenite, calcined. Examples thereof include silicates such as pearlite, calcium silicate and sodium silicate, hydroxides such as aluminum oxide, magnesium carbonate and calcium hydroxide, ferric carbonate, zinc oxide, iron oxide, aluminum phosphate and barium sulfate. .. One of these may be used alone, or two or more may be used in any combination and ratio. Of these, talc is more preferable from the viewpoint of improving the storage elastic modulus and transparency.

The particle size of the inorganic particles is not particularly limited. For handling reasons, the average particle size is preferably 0.5 μm or more, more preferably 0.6 μm or more, still more preferably 0.7 μm or more, and particularly preferably 1.0 μm or more. On the other hand, the average particle size of the inorganic particles is preferably 50 μm or less, more preferably 30 μm or less, still more preferably 20 μm or less.
As a method for measuring the average particle size at this time, the specific surface area value per 1 g of powder measured by the powder specific surface area measuring device SS-100 (constant pressure air permeation method) manufactured by Shimadzu Corporation was obtained and conformed to JIS M8511. From the measurement result of the specific surface area by the air permeation method, a method of calculating the average particle size of the inorganic particles by the following formula can be mentioned.
Average particle size (μm) = 10000 x {6 / (specific gravity of inorganic particles x specific surface area)}

The main component resins of the surface layer and the back layer of the laminated sheet 1 preferably have crystallinity, that is, have a melting point.
When the main component resins of the surface layer and the back layer are crystalline, the melting point (Tm) of the resin is preferably 100 ° C. or higher in terms of heat resistance. On the other hand, when the temperature is 250 ° C. or lower, it is preferable in terms of secondary molding processability.
From this point of view, the melting points (Tm) of the main component resins of the surface layer and the back layer are preferably 100 ° C. or higher, more preferably 105 ° C. or higher, and more preferably 110 ° C. or higher. On the other hand, the temperature is preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and more preferably 180 ° C. or lower.

Here, the melting point (Tm) is determined by heating about 10 mg of the resin to −30 ° C. to 200 ° C. at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC) and holding the resin at 200 ° C. for 1 minute. This is the crystal melting peak temperature obtained from the thermogram measured when the temperature was lowered to −30 ° C. at a cooling rate of 10 ° C./min and then raised to 200 ° C. at a heating rate of 10 ° C./min again.

(Other resins)
If necessary, the surface layer and the back layer are made of resins other than the above, such as polyhydroxyalkanoate, polycarbonate, polyamide, polystyrene, polyolefin, acrylic resin, amorphous polyolefin, ABS, AS (acrylonitrile styrene), polycaprolactone, and polyvinyl alcohol. It may contain any one or more of synthetic resins such as resins and cellulose esters.
However, these "resins other than the above" are preferably less than 50 parts by mass, particularly less than 30 parts by mass, with respect to 100 parts by mass of the main component resin.

(Other ingredients)
The surface layer and back layer may be a lubricant, a plasticizer, an antioxidant, an antioxidant, a light stabilizer, an ultraviolet absorber, a dye, a pigment, an antioxidant, a crystal nucleating agent, an anti-blocking agent, and a light-resistant agent, if necessary. Various additives such as agents, plasticizers, heat stabilizers, flame retardants, mold release agents, antifogging agents, surface wetting improvers, incineration aids, dispersion aids, various surfactants, slip agents, starch, cellulose , Paper, wood flour, chitin / cellulosic, coconut shell powder, walnut shell powder and other fine powders of animal / plant substances, or mixtures thereof may be contained as "other components". These can be arbitrarily blended as long as the effects of the present invention are not impaired, and one type may be used alone or two or more types may be mixed and used.

The content of these "other ingredients" is not particularly limited. As a guide, it is preferably 0.01% by mass or more and 40% by mass or less with respect to the total amount of each layer.

(Preferable composition)
In the laminated sheet 1, it is preferable that the surface layer contains biodegradable aliphatic polyester as the main component resin and the back layer contains biodegradable aliphatic aromatic polyester as the main component resin, and the back layer contains inorganic particles. It is more preferable to include it.
As described above, since the surface layer on the outside of the container contains biodegradable aliphatic polyester, the container is less likely to be deformed even when exposed to a high temperature such as boiling water. Further, since the back layer inside the container contains a biodegradable aliphatic aromatic polyester, the secondary molding processability is improved.
When the back layer contains a biodegradable aliphatic aromatic polyester as a main component resin, the back layer is easily deformed at a high temperature and may have low heat resistance or rigidity. Therefore, by incorporating the inorganic particles in the back layer inside the container, it is possible to improve the heat resistance and rigidity while improving the secondary molding processability.
In particular, among the above, the surface layer of the laminated sheet 1 contains polylactic acid (PLA) or polybutylene succinate (PBS) as the main component resin, and the back layer contains polybutylene adipate terephthalate (PBAT) as the main component resin. It is preferable to contain talc, and it is more preferable that the back layer contains talc.

<Middle layer>
The intermediate layer of the laminated sheet 1 is a gas barrier layer.

(PVA resin)
The intermediate layer preferably contains a polyvinyl alcohol-based resin (PVA-based resin) as the main component resin.
Here, the "main component resin" means a resin having the highest content (mass%) among the resins constituting the intermediate layer. The content of the main component resin in the intermediate layer is preferably 50% by mass or more, particularly 70% by mass or more, particularly 80% by mass or more, and particularly 90% by mass or more (100% by mass) of the resin constituting the intermediate layer. Includes%).

The PVA-based resin is generally obtained by saponifying a polyvinyl ester-based resin obtained by polymerizing a vinyl ester-based monomer.
As the PVA-based resin in the laminated sheet 1, a copolymer containing a vinyl alcohol structural unit in the molecular chain as a repeating unit (hereinafter, also referred to as “PVA copolymer”) is preferable. Among them, a resin obtained by saponifying a polyvinyl ester-based copolymer obtained by copolymerizing a vinyl ester-based monomer and various monomers is preferable, and above all, it is saponified with a vinyl alcohol structural unit equivalent to the degree of saponification. A resin composed of the remaining vinyl ester structural unit is preferable.

By using a PVA copolymer as the main component resin of the gas barrier layer in the laminated sheet 1, it is possible to impart excellent gas barrier properties while maintaining secondary molding processability. Further, since the PVA copolymer has biodegradability, if it is used for the gas barrier layer, the entire laminated sheet 1 will have biodegradability. Therefore, the laminated sheet 1 and the container obtained from the laminated sheet 1 can be completely decomposed (no residue remains after biodegradation).

Vinyl ester-based monomers include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, and versatic acid. Vinyl and the like can be mentioned. Above all, vinyl acetate can be economically preferably used.

Examples of the monomer used for copolymerization with the vinyl ester-based monomer include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene, 3-butene-1-ol, and 4-pentene. Hydroxy group-containing α-olefins such as -1-ol, 5-hexene-1-ol, 3,4-dihydroxy-1-butene and derivatives such as acylated products thereof, acrylic acid, methacrylic acid, crotonic acid, maleic acid. , Unsaturated acids such as maleic anhydride and itaconic acid, salts thereof, monoesters, or nitriles such as dialkyl ester, acrylonitrile and metaacrylonitrile, amides such as diacetone acrylamide, acrylamide and methacrylamide, ethylene sulfonic acid and allyl Olefin sulfonic acids such as sulfonic acid and methallyl sulfonic acid or salts thereof, alkyl vinyl ethers, dimethyl allyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3 -Vinyl compounds such as dioxolane, glycerin monoallyl ether, 3,4-diacetoxy-1-butene, substituted vinyl acetates such as isopropenyl acetate, 1-methoxyvinyl acetate, vinylidene chloride, 1,4-diacetoxy-2- Butene, vinylene carbonate and the like can be mentioned.

The content of the structural unit derived from various monomers in the copolymer is preferably 1 to 20 mol%, and more preferably 2 mol% or more or 10 mol% or less.

= Modified PVA resin =
As the PVA-based resin in the laminated sheet 1, a modified PVA-based resin into which various functional groups have been introduced by post-modification can also be used.

The modified PVA-based resin includes a PVA copolymer having an acetoacetyl group by reaction with diketen, a PVA copolymer having a polyalkylene oxide group by reaction with ethylene oxide, and a hydroxyalkyl group by reaction with an epoxy compound and the like. Examples thereof include a PVA copolymer having the above, a PVA copolymer obtained by reacting an aldehyde compound having various functional groups, and the like.

Among the above, from the viewpoint of being excellent in biodegradability and being able to impart excellent gas barrier properties while maintaining the secondary molding processability, the main component resin of the intermediate layer is other than the vinyl alcohol structural unit and the vinyl ester structural unit. A modified PVA-based resin having the structural unit of is preferable.
As such a modified PVA-based resin, for example, a PVA copolymer having a primary hydroxyl group in the side chain and an ethylene-modified PVA copolymer are preferable in terms of melt moldability.
Of these, a PVA copolymer having a primary hydroxyl group in the side chain is preferable. For example, a PVA copolymer having a hydroxyalkyl group in the side chain, a PVA copolymer having a 1,2-diol structure in the side chain, and the like can be mentioned. Among them, a PVA copolymer having a 1,2-diol structure in the side chain is preferable.

The content of the modified species in the modified PVA resin (content of structural units other than vinyl alcohol structural unit and vinyl ester structural unit) is preferably 0.1 to 20 mol%, and more than 1 mol% or 10 mol%. The following is more preferable.
In particular, when a PVA copolymer having a primary hydroxyl group in the side chain is used, the content of the structural unit having a 1,2-diol structure in the side chain is preferably 0.1 to 20 mol%, particularly 1 mol. % Or more or 10 mol% or less, more preferably 2 mol% or more or 8 mol% or less.
Further, in the case of the ethylene-modified PVA copolymer, the content of the ethylene structural unit is preferably 0.1 to 20 mol%, particularly 1 mol% or more or 15 mol% or less, and 3 mol% or more or 10 mol% or less among them. In particular, it is more preferably 4 mol% or more or 9 mol% or less.

The average degree of polymerization of the PVA-based resin is preferably 300 to 3000 from the viewpoint of followability to the surface layer and the back layer, and more preferably 350 or more or 2500 or less, and further 400 or more or 2000 or less. preferable.
Further, the degree of saponification of the PVA-based resin is preferably 90.0 to 99.9 mol% from the viewpoint of gas barrier property, and among them, 99.0 mol% or more or 99.9 mol% or less, among which 99.5 mol. It is more preferably% or more or 99.9 mol% or less.

(Other resins)
If necessary, the intermediate layer may be made of a resin other than the above, for example, polyhydroxyalkanoate, polycarbonate, polyamide, polystyrene, polyolefin, acrylic resin, amorphous polyolefin, ABS, AS (acrylonitrile styrene), polycaprolactone, polyvinyl alcohol-based resin, etc. It may contain any one or more of synthetic resins such as cellulose ester.
However, these "resins other than the above" are preferably less than 50 parts by mass, particularly less than 30 parts by mass, with respect to 100 parts by mass of the main component resin.

(Other ingredients)
The intermediate layer is, if necessary, a lubricant, a plastic agent, an antioxidant, an antioxidant, a light stabilizer, an ultraviolet absorber, a dye, a pigment, an antioxidant, a crystal nucleating agent, an anti-blocking agent, a light-resistant agent, Various additives such as plasticizers, heat stabilizers, flame retardants, mold release agents, antifogging agents, surface wetting improvers, incineration aids, dispersion aids, various surfactants, slip agents, starch, cellulose, paper , Wood flour, chitin / cellulosic, coconut shell powder, walnut shell powder and other animal / plant substance fine powders, or mixtures thereof may be contained as "other components". These can be arbitrarily blended as long as the effects of the present invention are not impaired, and one type may be used alone or two or more types may be mixed and used.

The content of these "other ingredients" is not particularly limited. As a guide, it is preferably 0.01% by mass or more and 40% by mass or less with respect to the total amount of each layer.

<< This Laminated Sheet 2 >>
Next, the present laminated sheet 2 will be described.

Since the laminated sheet 2 has a biodegradable resin layer and a gas barrier layer and is a laminated sheet having biodegradability, it suffices to have either the biodegradable resin layer or the gas barrier layer. .. Therefore, the case where the biodegradable resin layer is a surface layer or a back layer is of course included, but the case where it is an intermediate layer is also included. Further, of course, the case where the gas barrier layer is an intermediate layer is included, but the case where the gas barrier layer is a surface layer or a back layer is also included. Above all, from the viewpoint of handleability and moisture resistance after molding, it is preferable that the biodegradable resin layer is the surface layer and the back layer, and the gas barrier layer is the intermediate layer.

When the storage elastic modulus of the laminated sheet at 110 ° C. is E' ₍₁₁₀₎ and the storage elastic modulus of the laminated sheet at 130 ° C. is E' ₍₁₃₀₎ , the _{laminated sheet 2 is E'(110).} Is 5 MPa to 100 MPa, and a represented by the following formula (1) is preferably ^{−0.2 to −9.0 × 10 -4.}

The above formula (1) shows the change in storage elastic modulus with temperature. More specifically, a in the above formula (1) is the average slope in the sections of 110 ° C. and 130 ° C. when the temperature is on the x-axis (° C.) and the storage elastic modulus is on the y-axis (lоg (MPa)). Represents.

The laminated sheet 2 has a temperature range in which the gas barrier layer can be uniformly formed as long as the average inclination represented by the above formula (1) is ^{within the range of −0.2 to −9.0 × 10 -4.} Because of its wide width, it can have excellent secondary moldability.
From this point of view, the above a is ^{preferably −0.2 to −9.0 × 10 -4} , and more preferably −0.1 or more or 0 or less.

In order for the laminated sheet 2 to satisfy the above formula (1), the type of the main component resin constituting the biodegradable resin layer may be changed, or the type of the copolymerization component of the main component resin may be changed. The molecular weight of the component resin may be changed, or the biodegradable resin layer may contain inorganic particles. Further, the thickness ratio of the biodegradable resin layer and the gas barrier layer may be adjusted. In particular, since the type of the main component resin constituting the biodegradable resin layer and the thickness ratio of the biodegradable resin layer and the gas barrier layer are greatly affected, the biodegradability is reduced while reducing the thickness ratio of the gas barrier layer in the laminated sheet 2. It is preferable that the laminated sheet 2 satisfies the above formula (1) by adjusting the type of the main component resin constituting the resin layer.

<Biodegradable resin layer>
The biodegradable resin layer of the laminated sheet 2 may be the same as the surface layer and the back layer of the laminated sheet 1. A preferred embodiment of the biodegradable resin layer is the same as that described in the above <surface layer and back layer>.

<Gas barrier layer>
The gas barrier layer of the laminated sheet 2 may be the same as the intermediate layer of the laminated sheet 1. A preferred embodiment of the gas barrier layer is the same as that described in the above <intermediate layer>.

<< Configuration of main laminated sheets 1 and 2 >>
The laminated sheets 1 and 2 may be provided with at least a biodegradable resin layer and a gas barrier layer. In particular, the laminated sheet 1 is intermediate between at least a surface layer and a back layer as a biodegradable resin layer and a gas barrier layer. It suffices to have a layer.
Therefore, between the surface layer and the intermediate layer in the present laminated sheet 1, between the back layer and the intermediate layer, between the biodegradable resin layer and the gas barrier layer in the present laminated sheet 2, and further, the biodegradable resin layer or An "other layer" may be provided on the outside of the surface layer or the outside of the back layer.

Here, examples of the "other layer" include an anchor coat layer, a heat seal layer, an adhesive layer, a printing layer, a laminate layer, a protective layer, and the like. However, it is not limited to these.

(Adhesive layer)
It is preferable that an adhesive layer is interposed between the surface layer and the intermediate layer and / or between the back layer and the intermediate layer in the laminated sheet 1.
Further, it is preferable that an adhesive layer is also interposed between the biodegradable resin layer and the gas barrier layer in the laminated sheet 2.

The adhesive layer can be formed from an adhesive resin composition.
The adhesive resin composition is capable of adhering a surface layer and an intermediate layer, a back layer and an intermediate layer, or a biodegradable resin layer and a gas barrier layer, and has biodegradability. It is preferable to have.
The composition of such an adhesive resin composition is not particularly limited. _{As a preferred example, a polyester resin D 0} mainly containing an aliphatic polyester resin and / or an aliphatic aromatic polyester resin is graft-modified with α, β-unsaturated carboxylic acid and / or an anhydride thereof. The modified polyester resin D to be used can be mentioned.

The polyester resin D ₀ is not particularly limited as long as it mainly contains an aliphatic polyester resin and / or an aliphatic aromatic polyester resin.
The "mainly containing" in the polyester resin D _0, usually refers to the content of the polyester resin D in ₀ is not less than 50 wt%.

Further, if the polyester-based resin D ₀ mainly contains an aliphatic polyester-based resin and / or an aliphatic aromatic polyester-based resin, it may contain other resins as long as the effects of the present invention are not impaired. Good.
Other resins that may be contained in the polyester resin D ₀ include, for example, polyhydroxy alkanoate, aromatic polyester resin, polycarbonate, polyamide, polystyrene, polyolefin, acrylic resin, amorphous polyolefin, ABS, AS ( Acrylonitrile styrene), polycaprolactone, polyvinyl alcohol-based resin, synthetic resin such as cellulose ester, polylactic acid and the like can be mentioned.

_{The polyester resin D 0} is an aliphatic polyester resin and / or an aliphatic aromatic from the viewpoint of process moldability and adhesiveness when used as an adhesive layer used for a biodegradable laminated sheet having high biodegradability. It is preferably composed of only a polyester resin.

The polyester-based resin D ₀ contains an aliphatic polyester-based resin and an aliphatic aromatic polyester-based resin, or an aliphatic aromatic polyester, from the viewpoint of improving mechanical strength and adhesiveness when the biodegradable laminated sheet is used. It preferably contains a based resin, and more preferably contains an aliphatic polyester resin and an aliphatic aromatic polyester resin. When the polyester-based resin D ₀ contains an aliphatic aromatic polyester-based resin, the primary processability is improved.
When the polyester-based resin D ₀ contains an aliphatic polyester-based resin and an aliphatic aromatic polyester-based resin, the abundance ratio of the aliphatic polyester resin and the aliphatic aromatic polyester-based resin is the aliphatic polyester resin and the aliphatic aromatic. It is preferable that the total 100% by mass of the polyester-based resin contains 15 to 50% by mass of the aliphatic polyester-based resin and 50 to 85% by mass of the aliphatic aromatic polyester-based resin from the viewpoint of biodegradability and processability.

As the aliphatic aromatic polyester-based resin contained in the polyester-based resin D ₀ , at least a part of the repeating unit of the above-mentioned aliphatic polyester-based resin is replaced with an aromatic compound unit, preferably the above-mentioned above-mentioned aliphatic compound unit. A polyester-based compound containing an aliphatic diol unit, an aliphatic dicarboxylic acid unit, and an aromatic dicarboxylic acid unit as main constituent units, in which a part of the aliphatic dicarboxylic acid unit of the aliphatic polyester resin is replaced with an aromatic dicarboxylic acid unit. Resin is exemplified.

Examples of the aromatic compound unit include an aromatic diol unit having an aromatic hydrocarbon group which may have a substituent and an aromatic dicarboxylic acid having an aromatic hydrocarbon group which may have a substituent. Examples thereof include an aromatic oxycarboxylic acid unit having an aromatic hydrocarbon group which may have a unit and a substituent. The aromatic hydrocarbon group may be a single ring, or a plurality of rings bonded or condensed with each other. Specific examples of the aromatic hydrocarbon group include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, dinaphthylene group, diphenylene group and the like.

Specific examples of the aromatic dicarboxylic acid component that gives an aromatic dicarboxylic acid unit include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and the like. Of these, terephthalic acid is preferable.
The aromatic dicarboxylic acid component may be a derivative of an aromatic dicarboxylic acid compound. For example, the derivative of the aromatic dicarboxylic acid component exemplified above is preferable, and among them, a lower alkyl ester having 1 or more and 4 or less carbon atoms, an acid anhydride and the like can be mentioned. Specific examples of the derivative of the aromatic dicarboxylic acid compound include lower alkyl esters such as methyl ester, ethyl ester, propyl ester and butyl ester of the above-exemplified aromatic dicarboxylic acid component; and the above-exemplified aromatic dicarboxylic acid such as succinic anhydride. Cyclic acid anhydride as an acid component; and the like can be mentioned. Of these, dimethyl terephthalate is preferable.

Specific examples of the aromatic diol component that gives the aromatic diol unit include xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, and 2,2-bis (. Examples thereof include 4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, and bis (4-β-hydroxyethoxyphenyl) sulfonic acid. The aromatic diol component may be a derivative of an aromatic diol compound. Further, it may be a compound having a structure in which a plurality of aliphatic diol compounds and / or aromatic diol compounds are dehydrated and condensed with each other.

Specific examples of the aromatic oxycarboxylic acid component that gives the aromatic oxycarboxylic acid unit include p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid. The aromatic oxycarboxylic acid component may be a derivative of the aromatic oxycarboxylic acid compound. Further, it may be a compound (oligomer) having a structure in which a plurality of aliphatic oxycarboxylic acid compounds and / or aromatic oxycarboxylic acid compounds are dehydrated and condensed with each other. That is, an oligomer may be used as a raw material.

When an optical isomer is present in the aromatic compound component that gives these aromatic compound units, any of D-form, L-form, and racemic form may be used. Further, the aromatic compound component is not limited to the above example as long as an aromatic compound unit can be given. Further, one type of aromatic compound component may be used alone, or two or more types may be used in any combination and in a ratio.

As the aliphatic aromatic polyester resin, it is preferable to use an aromatic dicarboxylic acid component as a component that gives an aromatic compound unit, and the content of the aromatic dicarboxylic acid unit in this case is the aliphatic dicarboxylic acid unit and the aromatic acid. Based on the total amount of the dicarboxylic acid unit (100 mol%), it is preferably 10 mol% or more and 80 mol% or less. Further, it is preferable to use terephthalic acid as the aromatic dicarboxylic acid component, and as the aliphatic aromatic polyester resin, it is preferable to use polybutylene terephthalate adipate and / or polybutylene terephthalate succinate resin.

The mass average molecular weight of the polyester resin D ₀ is a polystyrene-equivalent value measured by GPC, usually 5,000 to 1,000,000, preferably 20,000 to 500,000, and particularly preferably 50,000. ~ 400,000. If the mass average molecular weight of the polyester resin is too large, the melt viscosity tends to be high and it tends to be difficult to melt-mold, and conversely, if it is too small, the molded product tends to be brittle.

Commercially available products of polyester resin D ₀ include, for example, "Ecoflex" manufactured by BASF, which contains polybutylene terephthalate adipate as the main component, and a polycondensation polymer of succinic acid / adipic acid / 1,4-butanediol as the main component. PTTMCC "BioPBS" manufactured by Biochem Co., Ltd. can be mentioned.
Further, as an arbitrary component, "Aonilex" manufactured by Kaneka Corporation can be mentioned as a polyhydroxy alkanoate which may be contained in the polyester resin.

= Modified polyester resin D =
The modified polyester resin D is obtained by graft-modifying the above-mentioned polyester resin D ₀ with α, β-unsaturated carboxylic acid and / or its anhydride.
The polyester-based resin D ₀ is biodegradable because it contains an aliphatic polyester-based resin and / or an aliphatic aromatic polyester-based resin, and the polyester-based resin D ₀ is α, β-unsaturated carboxylic acid and / or its. The modified polyester resin D obtained by graft modification with an anhydride also has a basic skeleton of an aliphatic polyester or an aliphatic aromatic polyester, and is biodegradable because it is modified by a slight amount. is there.

Specific examples of the α, β-unsaturated carboxylic acid and / or its anhydride used for graft modification to the polyester resin D _{0 are α, β-unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid;} Examples thereof include α, β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citrus acid, tetrahydrophthalic acid, crotonic acid and isocrotonic acid, derivatives thereof and anhydrides thereof, preferably α, β-unsaturated. Anhydride of dicarboxylic acid can be used. Particularly preferred is maleic anhydride.
These α, β-unsaturated carboxylic acids and / or their anhydrides are not limited to the case where one type is used alone, and two or more types may be used in combination.

The method for graft-modifying the polyester resin D ₀ with α, β-unsaturated carboxylic acid and / or its anhydride is not particularly limited, and a known method can be used. Although graft modification can be performed only by thermal reaction, it is preferable to use a radical initiator in order to enhance the reactivity. Examples of the reaction method include a solution reaction, a reaction as a suspension, and a reaction in a molten state without using a solvent or the like, and among them, the reaction in a molten state is preferable.

The modified polyester resin D may be obtained by using two or more kinds of _{polyester resins D 0.} When two or more types of polyester resin D ₀ are used, the polyester resin D ₀ can be obtained as a modified polyester resin D by mixing the polyester resin D 0 in advance and then graft-modifying with α, β-unsaturated carboxylic acid and / or its anhydride. Often, two or more types of polyester resins D ₀ are graft-modified with α, β-unsaturated carboxylic acid and / or its anhydride to obtain a modified polyester resin D, and then all the modified polyester resins D are subjected to. It may be mixed.
That is, the adhesive resin composition of the present invention preferably uses an aliphatic polyester resin and / or a polyester resin mainly containing the above-mentioned aliphatic aromatic polyester resin, but the polyester resin is a fat. When the group polyester resin and the aliphatic aromatic polyester resin are contained, the aliphatic polyester resin is graft-modified with α, β-unsaturated carboxylic acid and / or its anhydride in advance, and the aliphatic aromatic polyester. You may prepare the system resin graft-modified with α, β-unsaturated carboxylic acid and / or its anhydride, and mix them to use as the modified polyester-based resin D.
Further, one of the aliphatic polyester resin and the aliphatic aromatic polyester resin may be graft-modified with α, β-unsaturated carboxylic acid and / or its anhydride, and mixed with the other resin for use. Good. The modified polyester resin D is, for example, a mixture of an aliphatic polyester resin graft-modified with α, β-unsaturated carboxylic acid and / or its anhydride and an aliphatic aromatic polyester resin. Alternatively, it may be a mixture of an aliphatic polyester-based resin graft-modified with α, β-unsaturated carboxylic acid and / or its anhydride and an aliphatic polyester-based resin.
Further, a mixture of an aliphatic polyester resin and an aliphatic aromatic polyester resin graft-modified with α, β-unsaturated carboxylic acid and / or an anhydride thereof may be used as the modified polyester resin D.
Further, the method for modifying the polyester resin D ₀ is not limited to one type, _{and a mixture of a plurality of resins obtained by modifying the polyester resin D 0} by two or more methods is used as the modified polyester resin D. You may use it.

The adhesive resin composition of the present invention uses an aliphatic aromatic polyester resin as an α, β-unsaturated carboxylic from the viewpoints of improving biodegradability, improving adhesiveness, moldability, and improving appearance when used as an adhesive layer. A mixture of a modified polyester resin D graft-modified with an acid and / or its anhydride and an aliphatic polyester resin, or a mixture of an aliphatic polyester resin and an aliphatic aromatic polyester resin is α, β-non. The modified polyester resin D graft-modified with saturated carboxylic acid and / or its anhydride is preferably a modified polyester resin, and from the viewpoint as a biodegradable resin composition required for home compost, an aliphatic aromatic polyester. It is more preferable that the modified polyester resin D obtained by mixing the modified polyester resin D graft-modified with α, β-unsaturated carboxylic acid and / or its anhydride and the aliphatic polyester resin is used as the modified polyester resin D.
In this case, the proportion (% by mass) of the modified polyester resin D obtained by graft-modifying the aliphatic aromatic polyester resin contained in the modified polyester resin with α, β-unsaturated carboxylic acid and / or its anhydride is , 50-90 with respect to 100% by mass of the total of the modified polyester resin D obtained by graft-modifying the aliphatic aromatic polyester resin with α, β-unsaturated carboxylic acid and / or its anhydride and the aliphatic polyester resin. Mass% is preferred. The ratio of the aliphatic polyester resin is 100 mass in total of the modified polyester resin D obtained by graft-modifying the aliphatic aromatic polyester resin with α, β-unsaturated carboxylic acid and / or its anhydride and the aliphatic polyester resin. 10 to 50% by mass is preferable with respect to%.

_{One type or two or more types of polyester resin D 0} may be mixed with the modified polyester resin D as long as the performance is not impaired.

The content of unsaturated carboxylic acid and / or its anhydride in the modified polyester resin D is not limited. Usually, it is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and further preferably 0.03% by mass or more. On the other hand, it is usually preferably 5.0% by mass or less, particularly preferably 4.0% by mass or less, and more preferably 3.0% by mass or less.
If the content of the unsaturated carboxylic acid and / or its anhydride in the modified polyester resin D is too small, the interlayer adhesiveness, particularly the adhesive force with the PVA resin layer tends to be insufficient. If the content of the unsaturated carboxylic acid and / or its anhydride in the modified polyester resin is too large, the stability during hot melt molding tends to decrease.
The content of unsaturated carboxylic acid and / or its anhydride in the modified polyester resin D can be determined from the spectrum obtained by ^{1 1 H-NMR measurement.}

The mass average molecular weight of the modified polyester resin D is a polystyrene-equivalent value measured by GPC, which is usually 5,000 to 1,000,000, and more preferably 20,000 or more or 500,000 or less. Among them, it is more preferably 50,000 or more or 400,000 or less. If the mass average molecular weight of the modified polyester resin D is too large, the melt viscosity tends to be high and it tends to be difficult to melt-mold, and conversely, if it is too small, the molded product tends to be brittle.

The adhesive layer may contain only one type of the above-mentioned modified polyester resin D, or may contain two or more types.

(Preferable embodiment)
Among the above, in particular, the present laminated sheet 1 has at least a structure in which a surface layer, a first adhesive layer, an intermediate layer, a second adhesive layer, and a back layer are laminated in this order, and the surface layer and the back layer are biodegradable. It is preferable that the layer is mainly composed of a degradable resin, and that the first adhesive layer, the intermediate layer and the second adhesive layer are biodegradable.

Further, the present laminated sheet 2 has at least a structure in which a biodegradable resin layer, an adhesive layer, and a gas barrier layer are laminated in this order, and the biodegradable resin layer is a layer containing a biodegradable resin as a main component. Moreover, it is preferable that the adhesive layer and the gas barrier layer have biodegradability.
The laminated sheet 2 has at least a configuration in which a first biodegradable resin layer, a first adhesive layer, a gas barrier layer, a second adhesive layer, and a second biodegradable resin layer are laminated in this order. The first biodegradable resin layer and the second biodegradable resin layer are layers mainly composed of a biodegradable resin, and the first adhesive layer, the gas barrier layer and the second It is more preferable that the adhesive layer has biodegradability.

<< Thickness of this laminated sheet >>
The thickness of the laminated sheets 1 and 2 is preferably 0.1 mm or more, and more preferably 0.3 mm or more, and more preferably 0.5 mm or more, from the viewpoint of the thickness after the secondary molding process. On the other hand, from the viewpoint of secondary molding processability, it is preferably 2.0 mm or less, more preferably 1.8 mm or less, and more preferably 1.6 mm or less.

In this laminated sheet 1, when the one having the higher storage elastic modulus or indentation elastic modulus at 110 ° C. is the surface layer and the one having the lower storage elastic modulus or indentation elastic modulus at 110 ° C. is the back layer, the thickness of the surface layer with respect to the thickness of the back layer. From the viewpoint of heat resistance, the ratio of (surface layer / back layer) is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.4 or more. On the other hand, from the viewpoint of secondary molding processability, it is preferably 9.0 or less, more preferably 4.0 or less, and even more preferably 2.3 or less.
The ratio of the surface layer to the thickness of the back layer when the laminated sheet is formed into a capsule container as shown in FIG. 1 and the outside of the container is the surface layer and the inside of the container is the back layer. It may be a thickness ratio (front layer / back layer).

From the viewpoint of gas barrier properties, the thickness of the intermediate layer or the gas barrier layer in the laminated sheets 1 and 2 is preferably 0.5 μm or more, more preferably 0.8 μm or more, and further preferably 1.0 μm or more. .. On the other hand, from the viewpoint of workability, it is preferably 700 μm or less, more preferably 500 μm or less, and more preferably 300 μm or less.

In the present laminated sheet 2, the ratio of the thickness of the gas barrier layer to the thickness of the biodegradable resin layer (gas barrier layer / biodegradable resin layer) is ^{preferably 4.1 × 10 -4} to 1.4. ^{Among them, 8.3 × 10 -4} or more is more preferable from the viewpoint of gas barrier property, and 0.33 or less is more preferable from the viewpoint of processability and economy.

<< Manufacturing method of this laminated sheet >>
The laminated sheets 1 and 2 can be produced by a coextrusion method. However, the method is not limited to the coextrusion method, and can be produced by, for example, a coating method, a laminating method, or another method.
For example, when the present laminated sheet 1 is produced by the coextrusion method, a composition for forming a surface layer, a composition for forming a back layer, a composition for forming an intermediate layer, and, if necessary, another adhesive layer or the like. Each of the compositions forming the layer can be prepared, heated and supplied to an extruder to be melted, and coextruded from a T-die into a sheet to prepare the present laminated sheet.

<< Physical characteristics of this laminated sheet >>
The laminated sheets 1 and / or 2 can obtain the following physical properties.

(Biodegradable)
The laminated sheets 1 and 2 are prepared to have a 100 mm square film within 12 weeks on a pilot scale under an aerobic composting environment of 58 ° C. described in ISO 16929 or JIS K6952, and the remaining 10% of the 2 mm flue remains. It can have satisfactory biodegradability.

(Oxygen permeability)
From the viewpoint of oxygen barrier properties, the laminated sheets 1 and 2 have an oxygen permeability of 5.0 cc / m ² · day · atm or less at 0 ° C. and / or room temperature (20 to 25 ° C.) and 50% RH. Of these, 4.0 cc / m ² · day · atm or less, and ^{more preferably 3.0 cc / m 2} · day · atm or less. The smaller the oxygen permeability, the more preferable, and the feasible lower limit is preferably 0.01 cc / m ² · day · atm or more.
The oxygen permeability of the laminated sheets 1 and 2 can be adjusted by, for example, adjusting the type and thickness of the intermediate layer or the gas barrier layer. However, it is not limited to these factors.

(Storage modulus)
The laminated sheets 1 and 2 preferably have a storage elastic modulus at 110 ° C. of 5 MPa to 100 MPa, more preferably 7 MPa or 95 MPa or less, and more preferably 10 MPa or more or 90 MPa or less.
The storage elasticity of the laminated sheets 1 and 2 can be adjusted by changing the type of the main component resin constituting the front and back layers or the biodegradable resin layer, changing the copolymerization component of the main component resin, or changing the main component resin. It can be appropriately adjusted by changing the molecular weight or by incorporating inorganic particles in the front and back layers or the biodegradable resin layer.

As a method for measuring the storage elastic modulus of the laminated sheets 1 and 2, a dynamic viscoelasticity measuring device (“DVA-200” manufactured by IT Measurement Control Co., Ltd.) is used and a tensile jig is used to measure the temperature. Examples thereof include a method of measuring at 100 to 250 ° C., a frequency of 10 Hz, and a heating rate of 3 ° C./min.

The storage elastic modulus of the laminated sheets 1 and 2 is (the storage elastic modulus of the surface layer × the thickness ratio of the surface layer to the total thickness of the surface layer, the back layer and the intermediate layer (gas barrier layer) layer) + (the storage elastic modulus of the back layer). × Thickness ratio of back layer to total thickness of surface layer, back layer and intermediate layer (gas barrier layer)) + (storage elastic modulus of intermediate layer (gas barrier layer) × total thickness of surface layer, back layer and intermediate layer (gas barrier layer) It can also be obtained by the thickness ratio of the intermediate layer (gas barrier layer) with respect to. That is, the storage elastic modulus of the laminated sheets 1 and 2 is calculated from the storage elastic modulus of each of the surface layer, the back layer and the intermediate layer (gas barrier layer) and the thickness of each of the surface layer, the back layer and the intermediate layer (gas barrier layer). It may be calculated by.
_{E t '= E 1' ×} (t 1 / t 1 + t 2 + t 3) + E 2 '× (t 2 / t 1 + t 2 + t 3) + E 3' × (t 3 / t 1 + t 2 + t 3)
(In the above equation, _Et ': storage elastic modulus of the laminated sheet, E ₁ ': storage elastic modulus of the surface layer, E ₂ ': storage elastic modulus of the back layer, E ₃ ': storage elasticity of the intermediate layer (gas barrier layer) Ratio, t ₁ : Surface layer thickness, t ₂ : Back layer thickness, t ₃ : Intermediate layer (gas barrier layer) thickness.)

(Tensile tension)
From the viewpoint of stretching tension, the laminated sheets 1 and 2 preferably have a maximum tensile strength of 0.5 MPa or more at 110 ° C., more preferably 0.6 MPa or more, and even more preferably 0.7 MPa or more.
The tensile tension is measured according to the method described in JIS C2133, with a test length (distance between gripping tools) of 20 mm, a test width of 15 mm, a tensile speed of 200 mm / min, a test temperature of 110 ± 2 ° C., and a test humidity of 50 ±. A method of measuring at 10% can be mentioned.

<<< This container >>
The container according to an example of the embodiment of the present invention (“the present container”) is a biodegradable container provided with a side wall portion and a bottom surface portion, and the side wall portion and the bottom surface portion have a surface layer, an intermediate layer and a back layer. The surface layer and the back layer are biodegradable resin layers, and the intermediate layer is a gas barrier layer.

The indentation elastic modulus of the surface layer of the side wall and the bottom surface of the container is higher than that of the back layer from the viewpoint of providing heat resistance in the surface layer and improving heat sealing property in the back layer. Is preferable. Among them, the difference in indentation elastic modulus between the surface layer and the back layer is preferably 10 MPa or more, and more preferably 100 MPa or more, particularly 200 MPa or more, particularly 500 MPa or more, and among them 1000 MPa or more.

Further, the indentation elastic modulus of at least one of the surface layer and the back layer in this container, that is, one or both layers, is preferably 100 MPa to 8000 MPa from the viewpoint of heat resistance and heat sealability.
From this point of view, the indentation elastic modulus of at least one of the surface layer and the back layer is preferably 100 MPa to 8000 MPa, more preferably 200 MPa or more or 7,000 MPa or less, and more preferably 300 MPa or more or 6000 MPa or less.

In addition, the indentation elastic modulus of the surface layer is made higher than the indentation elastic modulus of the back layer, the surface layer has heat resistance and strength, the back layer has good secondary molding processability, and the inside of the container has good heat sealability. The indentation elastic modulus of the surface layer in this container is preferably 500 MPa to 8000 MPa, particularly 1000 MPa or more or 7,000 MPa or less, particularly 1500 MPa or more or 6000 MPa or less, and more preferably 2000 MPa or more.
On the other hand, the indentation elastic modulus of the back layer is preferably 100 MPa to 3000 MPa, particularly preferably 1000 MPa or less, and further preferably 600 MPa or less.

The method for measuring the indentation elastic modulus of the surface layer and the back layer in the present container is the same as that of the present laminated sheet 1.

The container can be formed from, for example, the laminated sheet 1 or 2. However, the method for forming this container is arbitrary, and it can also be molded by, for example, injection molding.
For example, the container can be formed by heat vacuum forming with the surface layer of the laminated sheet 1 or 2 as the outside of the container and the back layer as the inside of the container. However, the method is not limited to this method.

This laminated sheet is excellent in secondary molding processability, and not only can the thickness of the gas barrier layer be uniformly molded even in a container having a relatively deep bottom, but also excellent heat resistance. Therefore, this laminated sheet is suitable as a container forming sheet, and is also suitable for forming this container.
At this time, by molding the surface layer of the laminated sheet as the outside of the container and the back layer as the inside of the container, both heat resistance and heat sealability can be achieved.
Here, the "secondary molding process" means a process of deforming a sheet into another shape or imparting another shape, and the processing method includes a thermoforming method such as vacuum forming or compressed air forming. Can be mentioned. However, it is not limited to these.

Next, as an example of this container, as shown in FIG. 1, a container having a collar portion (1) and a recessed portion (2) as a storage portion can be mentioned.
This container can be manufactured by vacuum forming the laminated sheet 1 or 2 in the same manner as in Examples described later.

The wall thickness of the collar portion (1) is preferably 0.1 mm or more, particularly preferably 0.5 mm or more, and more preferably 0.9 mm or more from the viewpoint of durability of the recess. On the other hand, from the viewpoint of secondary molding processability at the time of sheeting, it is preferably 2.0 mm or less, more preferably 1.5 mm or less, and more preferably 1.2 mm or less.

The recess (2) has a side wall portion (3) and a bottom surface portion (4), and when the plan view shape of the upper edge portion (2a) of the recess (2) is a non-circular shape, the shortest width L ₁ thereof. When the plan view shape of the upper edge portion (2a) of the concave portion (2) is circular, the ratio of the depth D of the concave portion (2) to the _{diameter L 1 (depth D / shortest width or diameter L 1} ) is When used as a container with a shallow drawing, it is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.5 or more. On the other hand, when used as a deep-drawn container, it is preferably 5.0 or less, more preferably 3.0 or less, and even more preferably 2.0 or less.

The average value of the wall thickness (also referred to as "average wall thickness") of the side wall portion (3) of the recess (2) is a gas barrier depending on the thickness due to the uniform wall thickness of this container, that is, the molded product by deep drawing molding. From the viewpoint of reducing the unevenness of the property and obtaining a packaging container having a higher gas barrier property (low oxygen permeability), it is preferably 15% or more of the wall thickness of the flange portion (1), particularly 18%. Above all, it is more preferable that it is 20% or more. On the other hand, from the viewpoint of uniformity of thickness in the shallowly drawn container, it is preferably 95% or less, particularly preferably 90% or less, and more preferably 80% or less of the wall thickness of the collar portion (1).

Regarding the side wall portion (3) of the recess (2), the difference between the maximum wall thickness and the minimum wall thickness is such that the unevenness of the gas barrier property is small, and a packaging container having a high gas barrier property (low oxygen permeability) can be obtained. Therefore, it is preferably 0.35 mm or less, more preferably 0.30 mm or less, and more preferably 0.25 mm or less. The smaller the difference between the maximum wall thickness and the minimum wall thickness is, the better from the viewpoint of barrier property, and 0.01 mm or more is preferable within a feasible range.
The container may not have the bottom surface portion (4) in FIG. 1, and the recess (2) may be composed of only the side wall portion (3).

Since this container can be biodegradable and has excellent gas barrier properties and heat resistance, it is an oxygen-airtight packaging container, a food packaging container, and especially a coffee bean container for a capsule-type coffee maker. It can be suitably used as (so-called "coffee capsule").

Further, the laminated sheet 1 or 2 may be used as a lid material for covering the collar portion (1) of the container. By integrating the laminated sheet 1 or 2 with the container as a lid material, it is possible to obtain biodegradability as a whole and excellent gas barrier property and heat resistance. In such an embodiment, it is preferable to provide a heat seal layer on the surface of at least one of the container and the lid material.
The lid material used for this container is not limited to the present laminated sheet 1 or 2, and can be selected and used from any resin, metal, paper, and laminated bodies thereof.

Since the laminated sheets 1 and 2 and the container have good biodegradability, as described above, the decomposition characteristics in an aerobic compost environment are good.
In addition, it can be an effective means not only in an aerobic compost environment, but also as a countermeasure against natural decomposition when staying in rivers and oceans, and problems that birds and marine organisms accidentally eat and accumulate in the body. Therefore, the effect is great.

<< How to make this container >>
The method for producing this container is arbitrary. For example, the present container can be produced by using the present laminated sheet 1 or 2, or the present container can be produced by injection molding or the like.

When the container is manufactured using the laminated sheet 1 or 2, it is preferable to perform heat vacuum forming with the surface layer of the laminated sheet 1 or 2 on the outside of the container and the back layer on the inside of the container.

When the laminated sheet 1 or 2 is vacuum formed by heating to produce the container, the heating temperature is 80 to 80 to that the gas barrier layer does not flow and the front and back layers or the biodegradable resin layer can be molded. The temperature is preferably 170 ° C. or higher, particularly preferably 100 ° C. or higher or 160 ° C. or lower, and particularly preferably 110 ° C. or higher or 150 ° C. or lower.

<<< Explanation of words >>>
When expressed as "X to Y" (X, Y are arbitrary numbers) in the present invention, unless otherwise specified, it means "X or more and Y or less" and "preferably larger than X" or "preferably better than Y". It also includes the meaning of "small".
Further, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it means "preferably larger than X" or "preferably less than Y". Including intention.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples.
The measurement method and evaluation method used in the present invention are as follows.

<Measurement of storage elastic modulus>
The storage elastic moduli (E') of the entire biodegradable laminated sheet (sample), the surface layer, and the back layer obtained in Examples and Comparative Examples were determined as follows.

A dynamic viscoelasticity measuring device (“DVA-200” manufactured by IT Measurement Control Co., Ltd.) is used and tension is applied to each of the surface layer, intermediate layer (gas barrier layer) and back layer of Examples 1 to 4 and Comparative Examples 1 and 2. Using a jig, the storage elastic modulus at a measurement temperature of -100 to 250 ° C., a frequency of 10 Hz, and a heating rate of 3 ° C./min was measured. The rate (E') is shown.

Further, the storage elastic modulus of the biodegradable laminated sheets (samples) of Example 1 and Comparative Examples 1 and 2 was measured by the same method as described above, and the storage elastic modulus (E') of the entire laminated sheet at 110 ° C. and 130 ° C. was measured. ) Is shown in the table.
On the other hand, in Examples 2 to 4, the storage elastic modulus of the entire laminated sheet at 110 ° C. and 130 ° C. was calculated by the following formula using the storage elastic moduli measured for each of the surface layer, the intermediate layer (gas barrier layer) and the back layer. I asked for E').
_{E t '= E 1' ×} (t 1 / t 1 + t 2 + t 3) + E 2 '× (t 2 / t 1 + t 2 + t 3) + E 3' × (t 3 / t 1 + t 2 + t 3)
(In the above equation, _Et ': storage elastic modulus of the entire laminated sheet, E ₁ ': storage elastic modulus of the surface layer, E ₂ ': storage elastic modulus of the back layer, E ₃ ': storage of the intermediate layer (gas barrier layer) Elastic modulus (40.9 MPa at 110 ° C., 27.9 MPa at 130 ° C.), t ₁ : Surface layer thickness (320 μm), t ₂ : Back layer thickness (320 μm), t ₃ : Intermediate layer (gas barrier layer) thickness (60 μm).)

In Example 1, the storage elastic modulus (E') of the entire laminated sheet actually measured as described above and the storage elastic modulus (E') of the entire laminated sheet calculated by the above formula as described above are calculated. As a result of comparison, the measured value was 77.0 MPa at 110 ° C., while the calculated value was 82.6 MPa, and at 130 ° C., the measured value was 52.0 MPa, while the calculated value was 54.3 MPa. Since it was there, it was confirmed that the values were almost the same.

Further, regarding the biodegradable laminated sheets (samples) obtained in Examples and Comparative Examples, the storage elastic modulus of each of the surface layer and the back layer and the thickness of each of the surface layer and the back layer were used to obtain 110 ° C. and 130 ° C. using the following formula. And the total storage elastic modulus of the front and back layers at 160 ° C. was calculated.
_{E a '= E 1' ×} (t 1 / (t 1 + t 2)) + E 2 '× (t 2 / (t 1 + t 2))
(In the above equation, E _a ': total storage elastic modulus of the front and back layers, E ₁ ': storage elastic modulus of the surface layer, E ₂ ': storage elastic modulus of the back layer, t ₁ : thickness of the surface layer, t ₂ : back layer The thickness of.)
Further, the temperature range in which the total storage elastic modulus of the front and back layers is 10 MPa to 100 MPa is shown in the table as a “molding processing temperature range”.

Further, when the storage elastic modulus of the entire biodegradable laminated sheet (sample) obtained in Examples and Comparative Examples is E' _{(110) at} 110 ° C. and the storage elastic modulus at 130 ° C. is E' _(130). The a represented by the following formula (1) is shown in the table as "inclination a".

<Measurement of indentation elastic modulus>
The indentation elastic modulus (Y) of each of the surface layer and the back layer of the biodegradable laminated sheet (sample) obtained in Examples and Comparative Examples was measured as follows.
Further, the surface layer and the back layer in the central portion of the side wall portion (3) of the biodegradable packaging container (sample) obtained by molding the biodegradable laminated sheet (sample) obtained in Examples and Comparative Examples into a capsule shape, respectively. The indentation elastic modulus (Y) of was measured.
Using a Shimadzu dynamic ultra-micro hardness tester (manufactured by Shimadzu Corporation, DUH-W201), the elastic modulus (pushing elastic modulus (Y)) measured by a triangular pyramid indenter (made of diamond, inter-weight angle 115 °) is measured. did.
The test mode is a load-unloading test, in which the triangular pyramid indenter is held for 5 seconds under the load when it reaches a depth of 10 μm from the surface of the sample, and then the load is removed and the depth of the triangular pyramid indenter is changed over time. An unloading curve was obtained.
_{Approximation using the maximum value (h max} ) of the depth of the triangular pyramid indenter in the loading process of the above test and the data of the unloading curve at 70% or more of the maximum test force among the unloading curves obtained in the above test. the slope of the straight line (S), and the depth at the point of intersection with the approximate straight line and the x-axis from the (h _r), was calculated modulus (Y) using the following equation. In the table, the calculated elastic modulus (Y) of the surface layer is shown as “surface layer Y”, and the elastic modulus (Y) of the back layer is shown as “back layer Y”.

<Tensile strength, tensile elongation at break>
According to the method described in JIS C2133, the maximum tensile strength (MPa) of the biodegradable laminated sheet (sample) obtained in Examples / Comparative Examples was measured under the following conditions, and the tensile strength at 110 ° C. was 110 ° C. The tensile elongation at break and the moldability at 110 ° C. were determined according to the following criteria, respectively.
Test length (distance between grippers): 20 mm
Test width: 15 mm
Speed: 200mm / min
Test temperature: 110 ± 2 ° C
Test humidity: 50 ± 10%

= Criteria for determining tensile strength =
○ (good): Maximum tensile strength is 0.5 MPa or more × (poor): Maximum tensile strength is less than 0.5 MPa

= Criteria for tensile elongation at break =
○ (good): Tensile breaking elongation is 200% or more × (poor): Tensile breaking elongation is less than 200%

= Criteria for moldability =
○ (good): Tensile strength at 110 ° C. is 0.5 MPa or more, and tensile elongation at break at 110 ° C. is 200% or more × (poor): Tensile strength at 110 ° C. is less than 0.5 MPa, or 110 Tensile breaking elongation at ° C is less than 200%

<Measurement of thickness of biodegradable packaging container (sample)>
For the biodegradable packaging container (sample) obtained in Examples and Comparative Examples, the thickness of each layer of each part of the side wall was measured using a thickness measuring device. At this time, the portions (3a), (3b), and (3c) of FIG. 1 are measured at three points each, and the average value thereof is taken as the thickness of each portion, and further, the portions (3a), (3b), and (3c) of FIG. 1 are shown. The average value of the thickness was taken as the average wall thickness of the side wall. Then, the maximum wall thickness and the minimum wall thickness of the side wall portion were obtained, and the thickness distribution of the side wall portion (all layers of the side wall portion) was calculated from the following formula using these numerical values.
Thickness distribution (all layers of side wall) = 100 x (maximum wall thickness of side wall-minimum wall thickness of side wall) / average wall thickness of side wall

The thickness distribution of the intermediate layer (gas barrier layer) is determined by observing the cross sections of FIGS. 1 (1), (3a), (3b), (3c) and (4) using an optical microscope. The thickness of the layer (gas barrier layer) is measured at 3 points each, and the average value thereof is taken as the thickness of each part. Further, the intermediate layer (gas barrier) in (1), (3a), (3b), (3c) and (4) of FIG. The average value of the thickness of the layer) was taken as the average wall thickness of the gas barrier layer. Then, the maximum wall thickness and the minimum wall thickness of the thickness of the intermediate layer (gas barrier layer) were obtained, and the thickness distribution (gas barrier layer) of the intermediate layer (gas barrier layer) was calculated from the following formulas using these numerical values.
Thickness distribution (gas barrier layer) = 100 x (maximum wall thickness of gas barrier layer-minimum wall thickness of gas barrier layer) / average wall thickness of gas barrier layer

= Evaluation criteria for thickness distribution (all layers of side wall) =
○ (good): Thickness distribution (all layers of side wall) is less than 70% × (poor): Thickness distribution (all layers of side wall) is 70% or more

= Evaluation criteria for thickness distribution (gas barrier layer) =
○ (good): Thickness distribution (gas barrier layer) is less than 60% × (poor): Thickness distribution (gas barrier layer) is 60% or more

<Measurement of oxygen permeability>
The oxygen permeability of the biodegradable packaging container (sample) obtained in Examples and Comparative Examples at 23 ° C. and 50% RH was measured as follows.
The measurement was performed using an oxygen permeability measuring device OX-TRAN (OX-TRAN2 / 21 manufactured by MOCON) according to the test method of oxygen gas permeability by the electrolytic sensor method described in JIS K7126-1 or ISO 1515-2. The amount of oxygen gas that passed through the test piece and was carried out of the cell by the nitrogen carrier gas was measured using an electrolytic sensor. By using air (21% by volume of oxygen) as the test gas under the conditions of 23 ° C. and 50% RH, and multiplying the obtained oxygen permeability by 100/21, the oxygen permeability of the biodegradable packaging container (sample) can be increased. Obtained.

<Example 1>
[Preparation of PVA-based resin having a 1,2-diol structure in the side chain]
Azobisisobutyronitrile was charged with 68.0 parts of vinyl acetate, 23.8 parts of methanol, and 8.2 parts of 3,4-diacetoxy-1-butene in a reaction vessel equipped with a reflux condenser, a dropping funnel, and a stirrer. 0.3 mol% (against charged vinyl acetate) was added, and the temperature was raised under a nitrogen stream with stirring to initiate polymerization. When the polymerization rate of vinyl acetate reaches 90%, m-dinitrobenzene is added to terminate the polymerization, and then the unreacted vinyl acetate monomer is removed from the system by blowing methanol vapor to the outside of the system. The polymer was prepared as a methanol solution.

Next, the methanol solution was further diluted with methanol, adjusted to a concentration of 45% and charged into a kneader, and a 2% methanol solution of sodium hydroxide was added to the vinyl acetate structure in the copolymer while maintaining the solution temperature at 35 ° C. The unit and the total amount of 3,4-diacetoxy-1-butene structural unit were added at a ratio of 10.5 mmol to 1 mol to carry out saponification. As the saponification progresses, the saponified product precipitates, and when it becomes particulate, it is filtered off, washed well with methanol and dried in a hot air dryer, and the target "1,2-diol structure in the side chain" A PVA-based resin having the above was prepared.
The degree of saponification of the obtained PVA-based resin was 99.2 mol% when analyzed by the amount of alkali consumed for hydrolysis of residual vinyl acetate and 3,4-diacetoxy-1-butene. The average degree of polymerization was 450 when analyzed according to JIS K 6726. The content of 1,2-diol structural unit ^{was calculated from the integrated value measured by 1} H-NMR (300 MHz proton NMR, d6-DMSO solution, internal standard substance; tetramethylsilane, 50 ° C.). It was 6 mol%.

[Preparation of modified polybutylene adipate resin]
100 parts of polybutylene adipate resin (BASF's "Ecoflex C1200"), 0.1 part of maleic anhydride, 2,5-dimethyl-2,5-bis (t-butyloxy) hexane as a radical initiator (Nippon Yushi) After dry blending 0.01 part of "Perhexa 25B" manufactured by Japan, this is a twin-screw extruder (diameter: 15 mm, L / D: 60, screw rotation speed: 200 rpm, mesh: 90/90 mesh, cylinder temperature: 210 ° C. ), Extruded into strands, cooled with water, and cut with a pelletizer to obtain a modified polybutylene adipate resin having a polar group in the shape of a cylindrical pellet.

[Preparation of biodegradable laminated sheet (sample)]
As the back layer forming composition, talc (MG-made by Fuji Tarku Kogyo Co., Ltd.) with respect to 70 parts by mass of polybutylene adipate terephthalate (PBAT (BASF Ecoflex C1200, MFR: 3.8 g / 10 minutes, melting point: 115 ° C.)). 115, average particle diameter: 14 μm) 30 parts by mass were mixed, preheated using an oven to hold at 70 ° C. for 5 hours, and then supplied to an extruder (cylinder temperature 150 ° C.) to melt. ..
On the other hand, as the surface layer forming composition, 90 parts by mass of polylactic acid (PLA, manufactured by Nature Works, Ingeo NW4032D, density 1.24 g / cm ³ , melting point 169 ° C.) and polybutylene succinate (PBS, manufactured by PTTMCC Biochem), BioPBS FZ91PM, density 1.23 g / cm ³ , melting point 115 ° C.) 10 parts by mass are mixed, and these are preheated in an oven so as to be held at 70 ° C. for 5 hours, and then an extruder (cylinder temperature 200). It was supplied to ℃) and melted.

Further, as the intermediate layer (gas barrier layer) forming composition, the PVA-based resin having a 1,2-diol structure in the side chain obtained above was supplied to an extruder (cylinder temperature 210 ° C.) and melted.
Furthermore, as the adhesive layer forming composition, the modified polybutylene adipate-based resin obtained above is preheated in an oven so as to be held at 70 ° C. for 5 hours, and then transferred to an extruder (cylinder temperature 220 ° C.). It was supplied and melted.

Each layer-forming composition melted as described above is co-extruded from a T-die into a sheet of 4 types and 5 layers (surface layer / adhesive layer / intermediate layer (gas barrier layer) / adhesive layer / back layer), and cast roll at 50 ° C. A biodegradable laminated sheet (sample) having a thickness of 1200 μm (surface layer / adhesive layer / intermediate layer (gas barrier layer) / adhesive layer / back layer: 540 μm / 30 μm / 60 μm / 30 μm / 540 μm) was obtained.
The obtained biodegradable laminated sheet (sample) was prepared on a pilot scale in an aerobic composting environment at 58 ° C. described in ISO16929 or JIS K6952, and a 100 mm square film was formed within 12 weeks, and a 2 mm fluid remaining within 10%. It was biodegradable.

[Preparation of biodegradable packaging container]
Next, using a vacuum forming machine, a secondary molding process (deep drawing) was performed with the surface layer of the obtained biodegradable laminated sheet (sample) as the outside of the container and the back layer as the inside of the container. That is, the biodegradable laminated sheet (sample) was rapidly heated by the upper and lower heaters (upper 500 ° C., lower 450 ° C., 40s), and when the sheet temperature reached 160 ° C., plug assist and vacuum forming were performed. A biodegradable packaging container (sample) was prepared by molding into a capsule shape described below. Table 1 shows the results of measuring the physical characteristics of the obtained packaging container.
The produced biodegradable packaging container has a capsule container shape as shown in FIG. 1, and has an annular collar portion (1) and a recess (2) as a storage portion in the collar portion (1). The container is provided, and the recess (2) has a side wall portion (3) and a circular bottom surface portion (4), and has a depth of D _{45 mm, an upper edge portion diameter of L 1} 45 mm, and a bottom surface portion diameter of L _2. It was 37 mm and the width of the collar was 0.9 mm.
The produced biodegradable packaging container is a 100 mm square film within 12 weeks on a pilot scale under an aerobic composting environment of 58 ° C. described in ISO16929 or JIS K6952, and the remaining 10% of the 2 mm flue remains. It was biodegradable.
The oxygen permeability of the produced biodegradable packaging container at 23 ° C. and 50% RH was 0.0497 cc / m ² · day · atm.

<Example 2>
In Example 1, the same as in Example 1 except that the surface layer forming composition was ^{formed only from polybutylene succinate (PBS, manufactured by PTTMCC Biochem, BioPBS FZ91PM, density 1.23 g / cm 3} , melting point 115 ° C.). To prepare a biodegradable laminated sheet (sample) and a biodegradable packaging container (sample).
The produced biodegradable laminated sheet (sample) and biodegradable packaging container were prepared on a pilot scale under an aerobic composting environment of 58 ° C. described in ISO16929 or JIS K6952, and a 100 mm square film of 2 mm was formed within 12 weeks. The remaining amount of the film was within 10%, and it was biodegradable.

<Example 3>
In Example 1, as the back layer forming composition, talc (Fuji talc) was used with respect to 95 parts by mass of polybutylene adipate terephthalate (PBAT (BASF Ecoflex C1200, MFR: 3.8 g / 10 minutes, melting point: 115 ° C.)). A biodegradable laminated sheet (sample) was prepared in the same manner as in Example 1 except that MG-115 manufactured by Kogyo Co., Ltd. and 5 parts by mass (average particle diameter: 14 μm) were mixed.
The produced biodegradable laminated sheet (sample) was prepared on a pilot scale under an aerobic composting environment of 58 ° C. described in ISO16929 or JIS K6952, and within 12 weeks, a 100 mm square film was formed within 10% of the remaining 2 mm flue. It was biodegradable.

<Example 4>
In Example 3, as the surface layer forming composition, talc (Fuji talc industry) with respect to 90 parts by mass of polybutylene adipate terephthalate (PBAT (BASF Ecoflex C1200, MFR: 3.8 g / 10 minutes, melting point: 115 ° C.)). A biodegradable laminated sheet (sample) was prepared in the same manner as in Example 3 except that MG-115 manufactured by the same company and 10 parts by mass (average particle diameter: 14 μm) were mixed.
The produced biodegradable laminated sheet (sample) was prepared on a pilot scale under an aerobic composting environment of 58 ° C. described in ISO16929 or JIS K6952, and within 12 weeks, a 100 mm square film was formed within 10% of the remaining 2 mm flue. It was biodegradable.

<Comparative example 1>
In Example 1, both the back layer forming composition and the surface layer forming composition were formed from only polybutylene succinate adipate-based biodegradable polyester resin (PBSA-based resin, density 1.39 g / cm ³ , melting point 145 ° C.). A biodegradable laminated sheet (sample) and a biodegradable packaging container (sample) were produced in the same manner as in Example 1 except that the thickness of the intermediate layer (gas barrier layer) was 135 μm.
The oxygen permeability of the produced biodegradable packaging container at 23 ° C. and 50% RH was 0.1238 cc / m ² · day · atm.

<Comparative example 2>
In Example 1, both the back layer forming composition and the surface layer forming composition were formed from only polylactic acid (PLA, manufactured by Unitica, Terramac HV-6250H, density 1.27 g / cm ³ , melting point 170 ° C.), and the intermediate layer (PLA, manufactured by Unitica, Teramac HV-6250H) was formed. A biodegradable laminated sheet (sample) and a biodegradable packaging container (sample) were produced in the same manner as in Example 1 except that the thickness of the gas barrier layer) was 150 μm.
The oxygen permeability of the produced biodegradable packaging container at 23 ° C. and 50% RH was 0.1286 cc / m ² · day · atm.

From the above examples and the test results that the present inventor has repeatedly performed so far, when forming a container using a biodegradable laminated sheet, the indentation elastic modulus of the surface layer on the outside of the container is the indentation elastic modulus of the back layer on the inside of the container. When it is higher than the indentation elastic modulus, preferably the difference is 10 MPa or more, not only the heat resistance is excellent, but also the secondary molding processability is excellent, and even in a container with a relatively deep bottom, the gas barrier layer It was found that the thickness can be uniformly formed. It can be considered that this is because the surface layer having a high indentation elastic modulus contributes to heat resistance and the back layer having a low indentation elastic modulus contributes to moldability.

Further, the storage elastic modulus of at least one of the front and back layers at 110 ° C. is adjusted to 5 MPa to 100 MPa, and / or the storage elastic modulus of the laminated sheet at 110 ° C. is set to 5 MPa to 100 MPa, and the inclination a is −0. It was found that by adjusting the size to 2 to −9.0 × 10 ^-4 , the thickness of the gas barrier layer can be uniformly formed even in a container having a relatively deep bottom while ensuring heat resistance.

(1) Brim part (2) Recessed part (3) Side wall part (4) Bottom part

Claims (13)

1. It has a surface layer, an intermediate layer and a back layer,
   The surface layer and the back layer are biodegradable resin layers, and the intermediate layer is a gas barrier layer.
   A biodegradable resin sheet in which the indentation elastic modulus of the surface layer is higher than the indentation elastic modulus of the back layer.
2. The biodegradable resin sheet according to claim 1, wherein the difference in indentation elastic modulus between the surface layer and the back layer is 10 MPa or more.
3. The biodegradable resin sheet according to claim 1 or 2, wherein the indentation elastic modulus of at least one of the surface layer and the back layer is 100 MPa or more and 8000 MPa or less.
4. The biodegradable resin sheet according to any one of claims 1 to 3, wherein at least one of the surface layer and the back layer contains 5% by mass or more of inorganic particles.
5. According to any one of claims 1 to 4, the surface layer and the back layer contain a biodegradable aliphatic polyester, a biodegradable aliphatic aromatic polyester, or a mixed resin composed of a combination thereof as a main component resin. The biodegradable resin sheet described.
6. The biodegradable resin sheet according to any one of claims 1 to 5, wherein the ratio of the thickness of the surface layer (surface layer / back layer) to the thickness of the back layer is 0.1 or more and 9.0 or less.
7. The biodegradable resin sheet according to any one of claims 1 to 6, wherein the intermediate layer contains a copolymer containing a vinyl alcohol structural unit in a molecular chain as a repeating unit as a main component resin.
8. The biodegradable resin sheet according to any one of claims 1 to 7, wherein an adhesive layer is interposed between the surface layer and the intermediate layer and / or between the back layer and the intermediate layer. ..
9. When the storage elastic modulus of the sheet at 110 ° C. is E'(110) and the storage elastic modulus of the sheet at 130 ° C. is E'(130), the E'(110) is 5 MPa to 100 MPa and The biodegradable resin sheet according to any one of claims 1 to 8, wherein a represented by the following formula (1) is −0.2 to −9.0 × 10 ^-4.
   

   
10. A container-forming sheet made of the biodegradable laminated sheet according to any one of claims 1 to 9.
11. A biodegradable container having a side wall and a bottom surface.
    The side wall portion and the bottom surface portion have a surface layer, an intermediate layer and a back layer, the surface layer and the back layer are biodegradable resin layers, the intermediate layer is a gas barrier layer, and the indentation elastic modulus of the surface layer is the back layer. A biodegradable container characterized by having a higher indentation modulus.
12. The biodegradable container according to claim 11, wherein the difference in indentation elastic modulus between the surface layer and the back layer is 10 MPa or more.
13. The biodegradable container according to claim 11 or 12, wherein the surface layer is the outside of the container and the back layer is the inside of the container.

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