JP6870141B1 - Laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrathin resin layer composed of a resin composition in which a resin contained is substantially composed of a biomass-derived resin and / or a biodegradable resin in order to deal with environmental problems and resource problems. To provide a laminate of a layer and a paper substrate.
A laminate comprising a paper base material and a resin layer composed of a resin composed of a biomass-derived resin and / or a biodegradable resin, and 95% by weight of the resin contained in the resin composition. A laminate in which the super is the resin derived from the biomass and / or the biodegradable resin, and the thickness of the resin layer is less than 30 μm.
[Selection diagram] Fig. 3

Description

The present invention relates to a laminate that can be suitably used for applications such as packaging.

Conventionally, as a film used for packaging foods and the like, a plastic film made of a resin derived from fossil resources such as petroleum, coal, and natural gas, or a laminate of the plastic and another sheet such as paper is widely used. ..

However, in order to deal with environmental problems such as global warming caused by carbon dioxide generated during incineration and resource problems such as oil depletion, while reducing the use of resins derived from fossil resources in film materials, so-called biomass-derived resins are used. It has been proposed to add resin.

Biomass is defined as "excluding resources (crude oil, petroleum gas, combustible natural gas and coal (fossil resources)" that are organic substances derived from animals and plants, according to the Biomass Utilization Promotion Basic Act (Act No. 52 of 2009). That is, biomass is a renewable, biologically-derived organic resource, for example, in the case of plant-derived, means an organic compound obtained by photosynthesis from carbon dioxide and water. Biomass is an organic substance and therefore. When burned, carbon dioxide is emitted, but the carbon contained in the carbon dioxide is derived from the carbon dioxide absorbed by the plant from the atmosphere. Therefore, even if the biomass is incinerated, the amount of carbon dioxide in the atmosphere increases as a whole. No, that is, biomass is a so-called carbon-neutral renewable resource.

For example, Patent Document 1 discloses a laminate including a paper base material and a resin layer containing a biomass-derived resin and a relatively large amount of petroleum-derived synthetic resin.

Japanese Unexamined Patent Publication No. 2008-188812

In Patent Document 1, the ratio of the biomass-derived resin to the resin constituting the resin layer is 80% by weight at the maximum (see Example 3 of Patent Document 1 [Table 1]), but in order to cope with environmental problems. It is preferable to further increase the proportion of the biomass-derived resin in the resin constituting the resin layer.

Further, in order to deal with the resource problem, it is preferable to reduce the thickness of the resin layer to make an ultrathin film. Thereby, the amount of resin required for forming the resin layer can be reduced.

Therefore, when the production of an ultrathin film was examined using a resin composition in which the contained resin is a resin derived from biomass, the resin composition is different from the resin composition made of a resin derived from fossil resources such as petroleum. , It turned out that it is difficult to process the molten thin film. Specifically, it has been found that a large neck-in occurs when a resin composition made of a biomass-derived resin is melt-extruded from an extruder via a T-die to form a film. The cause seems to be that the melting tension at the time of melting the biomass-derived resin is low.

The occurrence of neck-in reduces the width of the film, which not only makes it difficult to produce a wide film, but also significantly increases the thickness of the film edge, so it is necessary to trim and remove the edge. As a result, the product yield is reduced. Further, in addition to these problems, the thickness of the film other than the end portion is also increased due to the influence of the increase in the thickness of the end portion, and an ultrathin film cannot be produced.

Further, it was found that also in the resin composition in which the contained resin is a biodegradable resin, a large neck-in occurs during the hot-dip thin film processing as in the above resin composition, and the above-mentioned problem occurs due to the neck-in. ..

On the other hand, when the resin derived from fossil resources is mixed with the resin derived from biomass and / or the biodegradable resin in a relatively large amount (for example, 5% by weight or more of the resin contained in the resin composition), the above neck-in and this Since the problem of film thickness increase associated with the above does not occur, the problem is peculiar to the case of using a resin composition in which the contained resin is substantially composed of a biomass-derived resin and / or a biodegradable resin.

The present invention comprises an ultrathin resin layer composed of a resin composition in which the contained resin is substantially composed of a biomass-derived resin and / or a biodegradable resin in order to cope with the above-mentioned environmental problems and resource problems. , An object of the present invention is to provide a laminate of the resin layer and a paper base material.

As a result of diligent studies, the present inventors have found that even if a resin composition in which the contained resin is substantially composed of a biomass-derived resin and / or a biodegradable resin is used, an ultrathin film having a thickness of less than 30 μm is used. We have found that it is possible to produce a film and that the film can be laminated and integrated with a paper substrate, and completed the present invention.

The present invention
Paper base material, as well as
A laminate comprising a resin layer composed of a resin composed of a biomass-derived resin and / or a biodegradable resin.
More than 95% by weight of the resin contained in the resin composition is the biomass-derived resin and / or the biodegradable resin, and
The thickness of the resin layer is less than 30 μm.

The thickness of the resin layer is preferably less than 25 μm.

More preferably, the thickness of the resin layer is less than 20 μm.

The biomass-derived resin may be a biomass-derived polyolefin or polyester.

The polyolefin is preferably polyethylene.

The polyester is preferably polyethylene terephthalate.

The biodegradable resin is preferably derived from biomass.

It is preferable that the biodegradable resin is polylactic acid.

It is preferable that the resin contained in the resin composition is composed only of the biomass-derived resin and / or the biodegradable resin.

The thickness of the paper substrate may be 30 μm to less than 1000 μm.

The paper base material and the resin layer may be directly integrated.

The resin layer is preferably a single layer.

The resin layer is preferably an extrusion coating layer.

The present invention also relates to a packaging sheet made of any of the above-mentioned laminates, and a packaging body provided with the packaging sheet.

The laminate of the present invention comprises an ultrathin resin layer having a thickness of less than 30 μm even when a resin composition in which the contained resin is substantially composed of a biomass-derived resin and / or a biodegradable resin is used. be able to.

Since the resin in the resin layer contained in the laminate of the present invention is substantially composed of a biomass-derived resin and / or a biodegradable resin, the amount of carbon dioxide in the atmosphere as a whole is almost the same even if the resin layer burns. It does not increase and / or the resin layer is almost decomposed by the action of microorganisms in the environment. Therefore, the laminate of the present invention can cope with environmental problems such as global warming due to an increase in carbon dioxide in the atmosphere and environmental pollution by resins remaining in the environment.

Further, since the resin layer contained in the laminate of the present invention is extremely thin, the amount of resin required to form the resin layer can be suppressed. Therefore, the laminate of the present invention can make effective use of resources and can deal with resource problems.

Further, the paper base material contained in the laminate of the present invention is originally an organic substance derived from a plant and is based on paper, which is a carbon-neutral renewable resource, and therefore does not impose a burden on the environment.

Therefore, the laminate of the present invention is environmentally friendly, and similarly, the packaging sheet of the present invention made of the laminate is also environmentally friendly.

It is the schematic sectional drawing which shows the 1st aspect of the laminated body of this invention. It is the schematic sectional drawing which shows the 2nd aspect of the laminated body of this invention. It is a schematic overall view of one aspect of a screw in an extruder used for forming a resin layer constituting the laminated body of this invention.

[Laminate]
The present invention
Paper base material, as well as
A laminate comprising a resin layer composed of a resin composed of a biomass-derived resin and / or a biodegradable resin.
More than 95% by weight of the resin contained in the resin composition is the biomass-derived resin and / or the biodegradable resin, and
It is a laminated body in which the thickness of the resin layer is less than 30 μm.

The laminate of the present invention includes the resin layer on at least one surface of a paper base material. Therefore, the laminate of the present invention may be provided with the resin layer only on one surface of the paper base material, or may be provided with the resin layer on both surfaces of the paper base material.

The thickness of the laminate of the present invention provided with the paper base material and the resin layer is not particularly limited, but is preferably less than 1000 μm, more preferably less than 800 μm, and even more preferably less than 600 μm. The thickness of the laminate of the present invention is preferably 30 μm or more, more preferably 100 μm or more, and even more preferably 200 μm or more. Therefore, the thickness of the laminate of the present invention is preferably 30 μm to less than 1000 μm, more preferably 100 μm to less than 800 μm, and even more preferably 200 μm to less than 600 μm.

{Paper base material}
The laminate of the present invention comprises a paper substrate. Although there may be a plurality of paper substrates, it is preferable that the number of paper substrates is one in order to suppress the overall layer thickness.

The paper base material is a base material made of paper and has a sheet shape, and the thickness thereof is preferably less than 1000 μm, more preferably less than 800 μm, and even more preferably less than 600 μm. The thickness of the paper base material is preferably 30 μm or more, more preferably 100 μm or more, and even more preferably 200 μm or more. Therefore, the thickness of the paper substrate is preferably 30 μm to less than 1000 μm, more preferably 100 μm to less than 800 μm, and even more preferably 200 μm to less than 600 μm.

The raw material for the paper base material is not particularly limited, and examples thereof include wood pulp such as softwood pulp and hardwood pulp. A small amount of non-cellulosic fibers such as rayon fiber, polyethylene fiber, and cotton fiber may be mixed with wood pulp.

The type of the paper base material is not particularly limited, and various types of paper such as printing paper, information paper, wrapping paper, and hybrid paper can be used.

The basis weight of the paper substrate also is not particularly limited, for example, less than ^{15~100g / m 2, 20~90g / m} 2, or it is used of less than 21~75g / ^{m 2} it can.

The paper base material faces the resin layer described later. Another layer such as an adhesive layer may be interposed between the paper base material and the resin layer. However, in order to suppress the overall layer thickness, it is preferable that no other layer is interposed between the paper base material and the resin layer. That is, it is preferable that the paper base material and the resin layer come into direct contact with each other.

{Resin layer}
The laminate of the present invention comprises a resin layer composed of a resin composition containing a biomass-derived resin and / or a biodegradable resin. Although there may be a plurality of resin layers, it is preferable that there is only one resin layer in order to suppress the overall layer thickness and the amount of resin used. That is, the resin layer is preferably a single layer.

The upper limit of the thickness of the resin layer in the laminate of the present invention is less than 30 μm, preferably less than 25 μm, and more preferably less than 20 μm. The lower limit of the thickness of the resin layer is not particularly limited, but is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more.

The thickness of the resin layer is preferably uniform, but when the thickness is non-uniform, the maximum thickness of the resin layer is less than 30 μm, preferably less than 25 μm, and more preferably less than 20 μm. The minimum thickness of the resin layer is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more.

Since the resin layer contained in the laminate of the present invention is thus extremely thin, the amount of resin required to form the resin layer can be suppressed. Therefore, the laminate of the present invention can make effective use of resources and can deal with resource problems.

(Resin composition)
In the laminate of the present invention, more than 95% by weight of the resin contained in the resin composition is a biomass-derived resin and / or a biodegradable resin. That is, in the laminate of the present invention, more than 95% by weight (based on the total weight of the resin) of the resin contained in the resin composition is a biomass-derived resin or a biodegradable resin, or a biomass-derived resin and raw material. It is a mixture of degradable resins.

The blending ratio of the biomass-derived resin and / or the biodegradable resin in the resin contained in the resin composition is preferably more than 96% by weight (based on the total weight of the resin; the same applies hereinafter), more than 97% by weight. More than 98% by weight is even more preferable, more than 99% by weight is even more preferable, and 100% by weight is particularly preferable. That is, it is particularly preferable that the resin contained in the resin composition is composed only of a biomass-derived resin and / or a biodegradable resin. By increasing the blending ratio of the biomass-derived resin and / or the biodegradable resin in this way, it is possible to reduce or avoid the use of the petroleum-derived resin in the laminate of the present invention, and it is possible to deal with environmental problems. Can be done.

When the resin contained in the resin composition contains a resin derived from biomass or another resin other than the biodegradable resin, the other resin is derived from fossil resources such as petroleum, coal, and natural gas. Here, the resin derived from fossil resources means that all the monomers constituting the resin are derived from fossil resources. Therefore, in the other resins, all the monomers constituting the resin are derived from fossil resources. When the resin contained in the resin composition contains a resin derived from biomass or another resin other than the biodegradable resin, the blending ratio of the other resin is less than 5% by weight (based on the total weight of the resin or less). , The same), preferably less than 4% by weight, more preferably less than 3% by weight, even more preferably less than 2% by weight, even more preferably less than 1% by weight. It is particularly preferable that the resin contained in the resin composition does not contain any resin other than the biomass-derived resin or the biodegradable resin.

(Biomass-derived resin)
The biomass-derived resin is not particularly limited, and various thermoplastic resins can be used, and for example, a biomass-derived polyolefin, polyester, or a mixture thereof may be used.

As mentioned above, biomass is an organic resource derived from animals and plants (excluding crude oil, petroleum gas, combustible natural gas and coal (fossil resource)). In particular, those derived from plants are preferable. The plant is not particularly limited, and examples thereof include corn and sugar cane. Specific examples of biomass include sugars extracted from these plants.

The molecular weight of the biomass-derived resin is preferably 1000 or more, more preferably 2000 or more, and even more preferably 3000 or more.

The polyolefin is a polymer or copolymer of an olefin such as ethylene or propylene (hereinafter, may be referred to as a (co) polymer). The biomass-derived polyolefin in the present invention is a (co) polymer of a monomer containing biomass-derived ethylene.

The method for producing ethylene derived from biomass is not particularly limited, and conventionally known methods can be used. Hereinafter, an example of a method for producing ethylene-derived ethylene will be described.

Biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use fermented ethanol derived from biomass obtained from plant raw materials.

Biomass-derived fermented ethanol refers to ethanol that has been purified by contacting a culture solution containing a carbon source such as saccharides obtained from a plant with a microorganism that produces ethanol or a product derived from a crushed product thereof. Conventionally known methods such as distillation, membrane separation, and extraction can be applied to the purification of ethanol from the culture solution. For example, a method of adding benzene, cyclohexane or the like and azeotropically boiling the mixture, or removing water by membrane separation or the like can be mentioned.

Then, ethylene can be produced by dehydrating ethanol derived from biomass. A catalyst is usually used when ethylene is obtained by a dehydration reaction of ethanol, but the catalyst is not particularly limited, and a conventionally known catalyst such as γ-alumina can be used.

By carrying out the dehydration reaction of ethanol in this way, a mixture of ethylene, water and a small amount of unreacted ethanol can be obtained. However, since ethylene is a gas at about 5 MPa or less at room temperature, water and water and a small amount of unreacted ethanol are separated from the mixture. Ethylene can be obtained except for ethanol. Gas-liquid separation can be performed by a known method.

The biomass-derived polyolefin in the present invention can be obtained by (co) polymerization of a monomer containing biomass-derived ethylene. Since ethylene derived from biomass is used as the monomer as a raw material, the polymerized polyolefin is derived from biomass. As the biomass-derived ethylene, it is preferable to use the ethylene obtained by the above-mentioned dehydration reaction of ethanol.

The monomer which is a raw material of the polyolefin derived from biomass may contain a small amount of ethylene and / or α-olefin such as propylene derived from fossil resources such as petroleum, or may further contain α-olefin derived from biomass.

The α-olefin has no particular limitation on the number of carbon atoms, but usually one having 3 to 20 carbon atoms can be used, and butylene, hexene, and octene are preferable. This is because butylene, hexene, and octene can be produced by polymerizing ethylene, which is a raw material derived from biomass. Further, by including such an α-olefin, the polymerized polyolefin has an alkyl group as a branched structure, so that it can be made more flexible than a simple linear one.

The biomass-derived polyolefin is preferably polyethylene, more preferably produced using biomass-derived ethylene, and even more preferably produced only from biomass-derived ethylene. By using ethylene, which is a raw material derived from biomass, it becomes possible to produce polyethylene using 100% biomass-derived components.

The method for polymerizing the monomer containing ethylene derived from biomass is not particularly limited, and a conventionally known method can be used. The polymerization temperature and the polymerization pressure may be appropriately adjusted according to the polymerization method and the polymerization apparatus. The polymerization apparatus is not particularly limited, and conventionally known apparatus can be used.

Since biomass-derived polyolefins are commercially available, commercially available ones may be used. For example, as the biomass-derived polyethylene, SBC818, which is a biopolyethylene sold by Braskem, can be preferably used.

Polyester is a polymer obtained by a polycondensation reaction of a diol unit and a dicarboxylic acid unit. The biomass-derived polyester in the present invention includes those in which either or both of the diol unit and the dicarboxylic acid unit forming the polyester are derived from biomass. Therefore, a biomass-derived polyester is formed from a diol unit containing a biomass-derived diol and a dicarboxylic acid unit containing a fossil resource-derived dicarboxylic acid, or a diol unit containing a fossil resource-derived diol and a biomass-derived dicarboxylic acid. It is formed from a dicarboxylic acid unit containing or is formed from a diol unit containing a diol derived from biomass and a dicarboxylic acid unit containing a dicarboxylic acid derived from biomass.

Examples of the diol unit include glycols such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, decanediol, and 2-ethyl-butyl-1-propanediol. Preferably, ethylene glycol is more preferred.

The biomass-derived ethylene glycol is preferably made from ethanol (biomass ethanol) produced from biomass as a raw material. Biomass-derived ethylene glycol can be obtained by dehydrating biomass ethanol to ethylene by a conventionally known method, and producing ethylene glycol via ethylene oxide obtained by oxidizing ethylene.

On the other hand, examples of the dicarboxylic acid as a dicarboxylic acid unit include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and derivatives thereof. These dicarboxylic acids can be used alone or in combination of two or more.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid and the like. Examples of the derivative of the aromatic dicarboxylic acid include lower alkyl esters of the aromatic dicarboxylic acid, specifically, methyl esters, ethyl esters, propyl esters, butyl esters and the like. Among these, terephthalic acid is preferable, and dimethyl terephthalate is preferable as the derivative of the aromatic dicarboxylic acid.

Examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, glutaric acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, dodecanedioic acid, dimeric acid, azelaic acid, dodecadicarboxylic acid, cyclohexanedicarboxylic acid and the like. Usually, a chain or alicyclic dicarboxylic acid having 2 or more and 40 or less carbon atoms can be mentioned. Examples of the derivative of the aliphatic dicarboxylic acid include lower alkyl esters such as methyl ester, ethyl ester, propyl ester and butyl ester of the aliphatic dicarboxylic acid, and cyclic acid anhydride of the aliphatic dicarboxylic acid such as succinic anhydride. .. Among these, as the aliphatic dicarboxylic acid, adipic acid, succinic acid, dimeric acid or a mixture thereof is preferable, and one containing succinic acid as a main component is particularly preferable. As the derivative of the aliphatic dicarboxylic acid, a methyl ester of adipic acid and succinic acid, or a mixture thereof is more preferable.

As the biomass-derived dicarboxylic acid, terephthalic acid produced from biomass as a raw material is preferable. For terephthalic acid derived from biomass, for example, bioisobutanol obtained by microbial fermentation using biomass as a raw material is dehydrated to isobutene by a conventionally known method, isobutene is quantified and converted to para-xylene, and further, para It can be obtained by a method of oxidizing xylene to induce terephthalic acid or the like.

Biomass-derived polyester can be obtained by a conventionally known method of polycondensing the above-mentioned diol unit and dicarboxylic acid unit. Specifically, a general method of melt polymerization including a step of performing an esterification reaction and / or a transesterification reaction of the above diol unit and a dicarboxylic acid unit and then performing a polycondensation reaction under reduced pressure, or a general method of melt polymerization or It can be produced by a known solution heating dehydration condensation method using an organic solvent or the like.

The amount of the diol unit used in producing the polyester derived from biomass is substantially equimolar to 100 mol of the dicarboxylic acid or its derivative, but generally, the esterification and / or transesterification reaction and / or Since there is distillation during the polycondensation reaction, it is used in excess of 0.1 to 20 mol%.

The polycondensation reaction is preferably carried out in the presence of a polymerization catalyst. The timing of adding the polymerization catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be added at the time of raw material preparation or at the start of reduced pressure.

Examples of the polymerization catalyst generally include compounds containing Group 1 to Group 14 metal elements excluding hydrogen and carbon in the periodic table. Specifically, at least one or more metals selected from the group consisting of titanium, zirconium, tin, antimony, cerium, germanium, zinc, cobalt, manganese, iron, aluminum, magnesium, calcium, strontium, sodium and potassium. Examples thereof include compounds containing an organic group such as a carboxylate, an alkoxy salt, an organic sulfonate, and a β-diketonate salt, and inorganic compounds such as oxides and halides of these metals and mixtures thereof. Among these, metal compounds containing titanium, zirconium, germanium, zinc, aluminum, magnesium and calcium, and mixtures thereof are preferable, and titanium compounds, zirconium compounds and germanium compounds are particularly preferable. Further, since the polymerization rate of the catalyst is high when it is melted or dissolved at the time of polymerization, a compound which is liquid at the time of polymerization or which is soluble in an ester low polymer or polyester is preferable.

When a metal compound is used as the polymerization catalyst, the lower limit of the amount of metal with respect to the produced polyester is usually 5 ppm or more, preferably 10 ppm or more, and the upper limit is usually 30,000 ppm or less, preferably 1. It is 000 ppm or less, more preferably 250 ppm or less, and particularly preferably 130 ppm or less. If too much catalyst is used, not only is it economically disadvantageous, but the thermal stability of the polymer is low. If the amount of catalyst used is too small, the polymerization activity will be low, and the decomposition of the polymer will be easily induced during polymer production. As for the amount of catalyst to be used, it is preferable to reduce the amount of catalyst to be used because the amount of terminal carboxyl groups of the produced polyester is reduced as the amount of catalyst used is reduced.

The reaction temperature of the esterification reaction and / or transesterification reaction of the dicarboxylic acid unit and the diol unit is usually in the range of 150 to 260 ° C. The reaction atmosphere is usually under the atmosphere of an inert gas such as nitrogen or argon. The reaction pressure is usually 10 kPa at normal pressure. The reaction time is usually 1 hour to 10 hours.

The biomass-derived polyester is preferably polyethylene terephthalate (PET). PET can be obtained by a polycondensation reaction of ethylene glycol and terephthalic acid. Biomass-derived PET includes those in which either or both of ethylene glycol and terephthalic acid used in the synthesis are derived from biomass. Therefore, biomass-derived PET is formed from ethylene glycol containing biomass-derived material and terephthalic acid containing fossil resource-derived material, or terephthalic acid containing ethylene glycol containing fossil resource-derived material and biomass-derived material. It is formed from ethylene glycol, including those derived from biomass, and terephthalic acid, including those derived from biomass.

It is more preferable to use PET composed of only biomass-derived ethylene glycol and only biomass-derived terephthalic acid so that it can be formed from a 100% biomass-derived raw material.

Since the biomass-derived polyester is commercially available, a commercially available polyester may be used. For example, as the biomass-derived polyethylene terephthalate, CB602AB, which is a biopolyethylene terephthalate sold by FENC, can be preferably used.

(Biodegradable resin)
A biodegradable resin is a resin that is decomposed into a low molecular weight compound in nature by involving organisms, particularly microorganisms, in at least one process of decomposition.

The biodegradable resin used in the present invention is not particularly limited, and various thermoplastic resins can be used. The biodegradable resin may be derived from fossil resources, but is preferably derived from biomass.

The biodegradable resin is not particularly limited, and examples thereof include polylactic acid, polycaprolactone, polyhydroxyalkanoate, and polyglycolic acid. Polylactic acid is preferable as the biodegradable resin.

The polylactic acid here is obtained by polymerizing a monomer containing lactic acid as a main component, that is, a monomer having more than 50 mol%, preferably more than 60 mol%, and more preferably more than 70 mol% of lactic acid. As lactic acid, L-lactic acid, D-lactic acid, or a mixture thereof can be used. Therefore, the polylactic acid here is, for example, polyL-lactic acid having a structural unit of L-lactic acid, polyD-lactic acid having a structural unit of D-lactic acid, and polylactic acid having a structural unit of L-lactic acid and D-lactic acid. It is a polymer containing DL-lactic acid and a mixture thereof as main components.

The composition of polylactic acid is not particularly limited, but for example, the molar ratio can be D-lactic acid: L-lactic acid = 100: 0 to 85:15 or 0: 100 to 15:85.

Polylactic acid may be a copolymer of lactic acid and other hydroxycarboxylic acid units, or may contain a small amount of chain extender residue. Other hydroxycarboxylic acid units include, for example, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methyl. Examples thereof include bifunctional aliphatic hydroxycarboxylic acids such as butyric acid, 2-methyllactic acid and 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone and valerolactone. These may be used alone or in combination of two or more. Such other hydroxycarboxylic acid units are preferably used in less than 15 mol% of the total monomer.

As a method for polymerizing polylactic acid, conventionally known methods such as a condensation polymerization method and a ring-opening polymerization method can be adopted. For example, in the condensation polymerization method, L-lactic acid, D-lactic acid, or a mixture thereof can be directly dehydrated and condensed to obtain polylactic acid having an arbitrary composition and crystallinity. Further, in the ring-opening polymerization method (lactide method), polylactic acid can be obtained from lactide, which is a cyclic dimer of lactic acid, by using an appropriate catalyst while using a polymerization regulator or the like, if necessary. Lactide includes L-lactide, which is a dimer of L-lactic acid, D-lactide, which is a dimer of D-lactic acid, and DL-lactide, which is a dimer of D-lactic acid and L-lactic acid. , These are mixed as necessary and polymerized to obtain polylactic acid having an arbitrary composition and crystallinity.

Since polylactic acid is commercially available, commercially available ones may be used. For example, polylactic acid, TERRAMAC T E 2000C sold by Unitika Ltd., a 2003D available from NatureWorks can be suitably used.

The resin composition contains the biomass-derived resin and / or the resin containing the biodegradable resin, but in addition to the resin, if desired, additives commonly used in the art, such as antioxidants, heat. Stabilizers, UV absorbers, lubricants, antistatic agents, flame retardants, crystallization accelerators, fillers and the like may be added as long as the characteristics of the present invention are not impaired. On the other hand, the resin composition does not have to contain additives. In this case, the resin layer may be composed of only a biomass-derived resin and / or a biodegradable resin, and the laminate of the present invention may be provided with a resin layer composed of only a biomass-derived resin and / or a biodegradable resin.

{Additional layer}
When the laminate of the present invention includes the resin layer only on one surface of the paper substrate, the laminate further comprises an additional layer other than the resin layer on the surface of the paper substrate that does not face the resin layer. You may. Although there may be a plurality of additional layers, it is preferable that there is only one additional layer in order to suppress the overall layer thickness.

The additional layer may be a layer made of any material such as paperboard, non-woven fabric, or cloth, and may be a resin layer having a composition different from the composition of the resin layer described above. The resin layer as the additional layer is preferably made of a thermoplastic resin.

When the additional layer is a resin layer having a composition different from that of the resin layer described above, the resin layer as the additional layer is, for example, 95 weight of the resin contained in the resin composition constituting the resin layer. % Or less (based on the total weight of the resin; the same applies hereinafter), 90% by weight or less, or 85% by weight or less may be the biomass-derived resin and / or the biodegradable resin.

The thickness of the additional layer is not particularly limited, and is, for example, preferably less than 30 μm, more preferably less than 25 μm, and even more preferably less than 20 μm. The thickness of the additional layer is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. Therefore, the thickness of the additional layer is preferably 5 μm to less than 30 μm, more preferably 10 μm to less than 25 μm, and even more preferably 15 μm to less than 20 μm.

By providing an additional layer, both sides of the paper substrate can be protected. Further, when a resin layer is formed as an additional layer, water absorption by the paper base material of the laminate of the present invention can be prevented or reduced to impart waterproofness. Further, when the strength of the paper base material is low, the laminate of the present invention does not have the self-supporting property, and there is room for improvement in terms of handleability such as being easily bent, the strength of the paperboard or the like is relatively high. By providing an additional layer made of a material, the strength of the laminate of the present invention can be improved and the handleability can be improved.

When the laminate of the present invention includes an additional layer, another layer such as an adhesive layer may be interposed between the paper base material and the additional layer. However, it is preferable that no other layer is interposed between the paper base material and the additional layer. That is, it is preferable that the paper base material and the additional layer are in direct contact with each other.

{Arrangement}
FIG. 1 is a schematic cross-sectional view showing a first aspect of the laminated body of the present invention. In this aspect, a resin layer composed of a resin composition containing a biomass-derived resin and / or a biodegradable resin on one surface of the paper base material 11 constituting the laminate 1 (95 of the resin contained in the resin composition). More than% by weight of the biomass-derived resin and / or the biodegradable resin) 12 is present, and there is no layer on the other surface (upper side of FIG. 1) of the paper substrate 11, and the other The surface is open.

FIG. 2 is a schematic cross-sectional view showing a second aspect of the laminated body of the present invention. In this aspect, the resin layer 22 is present on one surface of the paper base material 21 constituting the laminate 2, and the additional layer 23 is further present on the other surface of the paper base material 21. The additional layer 23 is different from the resin layer 22.

{Use}
The use of the laminate of the present invention is not particularly limited, but it can be suitably used as a packaging sheet used for packaging various articles such as foods, for example. Furthermore, the present invention also relates to a packaging body including the packaging sheet. Examples of the package include those in which various articles such as foods are packaged with the laminate.

Since the laminate of the present invention includes a base material made of paper, which is a carbon-neutral material, and a resin layer substantially composed of a biomass-derived resin and / or a biodegradable resin, the resin layer burns. However, the amount of carbon dioxide in the atmosphere does not increase as a whole, and / or the resin layer is almost decomposed by the action of microorganisms in the environment. Therefore, the laminate of the present invention can cope with environmental problems such as global warming due to an increase in carbon dioxide in the atmosphere and environmental pollution by resins remaining in the environment.

Therefore, the laminate of the present invention is environmentally friendly, and similarly, the packaging sheet and the packaging body of the present invention made of the laminate are also environmentally friendly.

[Method for Producing Laminated Body of the Present Invention]
The laminate of the present invention
A step of melting the resin composition to obtain a molten resin composition with an extruder equipped with a double flight screw having two flights, a spiral main flight and a secondary flight.
A step of extruding the molten resin composition through a T-die to form the resin layer, and
It can be produced by a production method including a step of laminating the resin layer with the paper base material.

The above description of the laminate of the present invention applies to the resin composition, the paper base material, and the resin layer.

The manufacturing method is characterized by using an extruder equipped with a double flight screw having two flights, a spiral main flight and a secondary flight, in melting the resin composition.

FIG. 3 is a schematic overall view of one aspect of a screw in an extruder used in the manufacturing method.

The extruder is provided with a screw 3 in a cylinder (also referred to as a barrel) (not shown), and a resin composition charged into the cylinder from a supply port of the cylinder is a screw by a rotating mechanism such as a motor (not shown). It is sent forward by the rotation of 3 (to the right in FIG. 3).

Around the cylinder, heaters are provided, for example, divided into 2 to 10 along the longitudinal direction in order to heat the resin composition in the cylinder. Therefore, the resin composition in the cylinder is heated and melted in the process of being fed forward. Then, the molten resin composition is discharged from the front end portion of the cylinder.

The screw 3 shown in FIG. 3 is a so-called double flight screw having a main flight 31 and a sub flight 32 arranged in a spiral shape (spiral shape) around the screw shaft and the screw shaft. By using an extruder equipped with a double flight screw in this way, good melting and mixing / kneading of the resin composition and stable extrusion of the melted resin composition become possible, and the contained resin is derived from biomass. An ultrathin resin layer can also be formed by using a resin composition substantially composed of a resin and / or a biodegradable resin. In particular, by providing the sub-flight on the screw shaft corresponding to at least the compression portion of the extruder (the zone for melting, mixing and kneading the resin composition while compressing it), the melting, mixing and kneading of the resin composition can be further enhanced. Can be done well.

In the example shown in FIG. 3, the main flight 31 exists over the entire longitudinal direction of the screw 3, while a plurality of sub-flights 32 are separated along the longitudinal direction of the screw 3. The number of secondary flights is not particularly limited, but 2 to 4 is preferable, 2 or 3 is more preferable, and 2 is even more preferable. As described above, by using the extruder including the screw having a plurality of sub-flights, the resin composition can be melted, mixed and kneaded even better. In particular, by providing the secondary flight on the screw corresponding to at least the compression part and the quantification part (the zone for measuring the molten resin composition and stabilizing the extrusion amount) of the extruder, the resin composition can be melted and mixed. Kneading and quantitative extrusion can be performed even better.

It is preferable that the main flight 31 and the sub flight 32 have different lead angles. Thereby, the melting, mixing and kneading of the resin composition can be performed even better.

The extruder used in the above manufacturing method may be a single-screw extruder including one screw, but is preferably a twin-screw extruder having two screws. This enables more stable extrusion of the molten resin composition.

The diameter of the screw provided in the extruder used in the above manufacturing method is preferably small, for example, it can be 100 to 80 mm, and 90 mm is preferable. By reducing the diameter of the screw, the rotation speed of the screw can be increased, and better melting and mixing / kneading of the resin composition and more stable extrusion of the melted resin composition can be performed.

In the above manufacturing method, in the step of extruding the molten resin composition through the T die to form the resin layer, the molten resin composition discharged from the extruder is extruded through the T die to form a film. An ultrathin resin layer (film) can be formed by using a molten resin composition supplied from an extruder equipped with a double flight screw.

In the above production method, by using a molten resin composition supplied from an extruder equipped with a double flight screw, a resin composition in which the contained resin is substantially composed of a biomass-derived resin and / or a biodegradable resin can be obtained. Even if it is used, unexpectedly, the neck-in of the film extruded from the T-die is suppressed, the thickness increase of the film edge portion is suppressed, and the thickness increase of the film other than the edge portion is also suppressed. Therefore, an ultrathin resin layer (film) can be formed.

In the above manufacturing method, the resin layer thus formed is laminated with the paper base material. The laminating method is not particularly limited, but it is preferable that the paper base material and the resin layer are brought into direct contact with each other to be integrated. Then, it is more preferable that the paper base material is directly integrated by extrusion coating with a resin layer. That is, the resin layer is more preferably an extrusion coating layer.

It is preferable that the laminate thus obtained is cooled by a cooling roll to solidify the resin layer (film) and integrate it with the paper substrate.

If necessary, the resin layer (film) may be cast on a cooling drum and cooled to a predetermined temperature before contact with the paper base material.

In the above production method, even if a resin composition in which the contained resin is composed of a resin substantially derived from biomass and / or a biodegradable resin is used, the thickness is less than 30 μm, preferably less than 25 μm, and more preferably less than 20 μm. It is possible to provide an ultra-thin resin layer having.

Therefore, by the above manufacturing method,
A resin layer composed of a paper base material and a resin composition containing a biomass-derived resin and / or a biodegradable resin is provided.
More than 95% by weight of the resin contained in the resin composition is the biomass-derived resin and / or the biodegradable resin, and
It is possible to produce a laminate in which the thickness of the resin layer is less than 30 μm, preferably less than 25 μm, and more preferably less than 20 μm. As described above, the resin composition may not contain additives and may be composed of only the resin. In this case, the resin layer may be composed of only a biomass-derived resin and / or a biodegradable resin, and the laminate may be provided with a resin layer composed of only a biomass-derived resin and / or a biodegradable resin.

Since the laminate of the present invention is composed of a resin layer containing a resin substantially composed of a biomass-derived resin and / or a biodegradable resin, and carbon-neutral paper derived from a plant in the first place, even if it is incinerated, it is in the air. The amount of carbon dioxide in the resin layer does not increase as a whole, and / or the resin layer is almost decomposed by the action of microorganisms in the environment.

That is, the laminate of the present invention can satisfactorily suppress the load on the environment by either incineration or landfill disposal method.

Therefore, the laminate of the present invention can be used as an environmentally friendly packaging sheet that can cope with environmental problems such as global warming due to an increase in carbon dioxide in the atmosphere and environmental pollution due to resin remaining in the environment. it can.

[Example 1]
Commercially available Tokai Craft A (manufactured by Shin-Tokai Paper Co., Ltd., basis weight 75 g / m ² ) was used as the paper base material, and SBC818, which is a biopolyethylene sold by Braskem, was used as the resin composition. All the resins in the resin composition were biopolyethylene.
Using an extruder (E-90EXT manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) equipped with a double flight screw shown in FIG. 3 having a screw shaft diameter of 90 mm, the resin composition is melt-kneaded to a resin temperature of 315 ° C. and tension. When extruded from a T-die as a film having a width of 1230 mm at a speed of 200 m / min and laminated on a paper substrate, neck-in when extruded from the T-die was suppressed, and a 15 μm-thick resin layer was applied to the paper base. It could be formed on the material.

[Example 2]
As a paper base material, commercially available Raicho Pure White (basis weight 65 g / m ² manufactured by Chuetsu Pulp & Paper Co., Ltd.) was used, and as a resin composition, CB602AB, which is a biopolyethylene terephthalate sold by FENC, was used. All the resins in the material were biopolyethylene terephthalate.
Using an extruder (E-90EXT manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) equipped with a double flight screw shown in FIG. 3 having a screw shaft diameter of 90 mm, the resin composition is melt-kneaded to a resin temperature of 300 ° C. and tension. When extruded from a T-die as a film having a width of 1600 mm at a speed of 80 m / min and laminated on a paper substrate, neck-in when extruded from the T-die was suppressed, and a 20 μm-thick resin layer was used as a paper base. It could be formed on the material.

[Example 3]
As the paper substrate, using a commercial money killer (Daio Paper Corp. basis weight 30 g / m ^2), as a resin composition was used Terramac T E 2000C polylactic acid sold by Unitika Corporation. All the resins in the resin composition were polylactic acid.
Using an extruder (E-90EXT manufactured by Sumitomo Heavy Industries Modern Co., Ltd.) equipped with a double flight screw shown in FIG. 3 having a screw shaft diameter of 90 mm, the resin composition is melt-kneaded to a resin temperature of 230 ° C. and tension. When extruded from a T-die as a film having a width of 1460 mm at a speed of 100 m / min and laminated on a paper substrate, neck-in when extruded from the T-die was suppressed, and a 15 μm-thick resin layer was applied to the paper base. It could be formed on the material.

[Comparative Example 1]
The same resin composition as in Example 1 was extruded from the T-die in the same manner as in Example 1 except that a single flight screw lacking a secondary flight was used instead of the double flight screw shown in FIG. Although laminated on top, the neck-in when extruded from the T-die was large, and the thickness of the resin layer was 30 μm.

[Comparative Example 2]
The same resin composition as in Example 2 was extruded from the T-die in the same manner as in Example 2 except that a single flight screw lacking a secondary flight was used instead of the double flight screw shown in FIG. Although laminated on top, the neck-in when extruded from the T-die was large, and the thickness of the resin layer was 30 μm.

[Comparative Example 3]
The same resin composition as in Example 3 was extruded from the T-die in the same manner as in Example 3 except that a single flight screw lacking a secondary flight was used instead of the double flight screw shown in FIG. Although laminated on top, the neck-in when extruded from the T-die was large, and the thickness of the resin layer was 30 μm.

1 Laminated body of the first aspect 11 Paper base material 12 Resin layer 2 Laminated body of the second aspect 21 Paper base material 22 Resin layer 23 Additional layer 3 Screw 31 Main flight 32 Secondary flight

Claims (13)

Paper substrates with a basis weight of less than 15-100 g / m ² and
A laminate comprising a resin layer composed of a resin composed of a biomass-derived resin and / or a biodegradable resin.
The resin layer is one,
More than 95% by weight of the resin contained in the resin composition is the biomass-derived resin and / or the biodegradable resin, and
A laminate having a thickness of the resin layer of less than 30 μm ( ^{excluding those having an oxygen permeability of 10 ml / m 2} · day · atm or less at a temperature of 23 ° C. and a relative humidity of 0%). The laminate according to claim 1, wherein the thickness of the resin layer is less than 25 μm. The laminate according to claim 1, wherein the thickness of the resin layer is less than 20 μm. The laminate according to any one of claims 1 to 3, wherein the biomass-derived resin is a biomass-derived polyolefin or polyester. The laminate according to claim 4, wherein the polyolefin is polyethylene. The laminate according to claim 4 or 5, wherein the polyester is polyethylene terephthalate. The laminate according to any one of claims 1 to 6, wherein the biodegradable resin is derived from biomass. The laminate according to any one of claims 1 to 7, wherein the biodegradable resin is polylactic acid. The laminate according to any one of claims 1 to 8, wherein the resin contained in the resin composition comprises only the biomass-derived resin and / or the biodegradable resin. The laminate according to any one of claims 1 to 9 , wherein the paper base material and the resin layer are directly integrated. The laminate according to any one of claims 1 to 10 , wherein the resin layer is an extrusion coating layer. A packaging sheet made of the laminate according to any one of claims 1 to 11. A packaging body including the packaging sheet according to claim 12.

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