JP2009209202A - Sealant for polylactic acid resin, laminate having the sealant layer, cover and polylactic acid resin container sealed with the sealant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily releasable sealant which has adhesion with appropriate strength to the surface of a polylactic acid resin such as a container made of a polylactic acid resin and a laminated container having a layer of a polylactic acid resin and gives a good releasing feeling on opening and releasing such containers, a cover which has the sealant layer and is used for sealing a container made of a polylactic resin, and furthermore an easily openable sealed container made of a polylactic acid resin which is sealed with the sealant. <P>SOLUTION: The sealant for polylactic acid-based resins is composed of a resin composition comprising 15-80 pts.wt. ethylene-unsaturated carboxylic acid copolymer (A), 10-80 pts.wt. at least one resin (B) selected from polyethylene, an ethylene-α-olefin copolymer, an ethylene-vinyl ester copolymer, and an ethylene-unsaturated carboxylic acid ester copolymer, and 3-30 pts.wt. tackifying resin (C) (provided that the sum of (A), (B), and (C) is 100 pts.wt.). The cover for sealing a container made of a polylactic resin has a layer of the sealant, and the easily openable sealed container made of a polylactic acid resin is sealed with the sealant. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polylactic acid resin sealant, an easily peelable laminate of a polylactic acid resin having a sealant layer, a lid, and a polylactic acid resin container sealed using the sealant.

In recent years, from the viewpoint of global environmental conservation, reduction of carbon dioxide emission, which is particularly involved in global warming, has become an important issue.
In order to solve this problem, interest in the use of natural products, particularly plant-derived components, is increasing along with the recycling and use restrictions of synthetic resins, and development is underway.
Polylactic acid resin is a polymer of lactic acid, and lactic acid is a so-called renewable resource obtained by fermenting plant-derived raw materials such as starch and saccharides, but used resin is produced by microorganisms in soil and compost. Since it is decomposed, it has recently been used in various fields in place of conventional thermoplastic resins made from fossil resources such as petroleum.

However, since it has a characteristic that odor is relatively difficult to adhere to, it is possible to obtain a transparent and relatively high mechanical strength, containers for food, beverages, cosmetics, packaging films, bags, etc. The use in a wide range of fields ranging from the above-mentioned applications to the applications for packaging precision electronic parts is promising, and many application inventions, improved inventions, etc. have been proposed and some have already been put into practical use.
Also, for various containers, packaging films, bags, etc., a molded body made of a single polylactic acid resin may be used, but it is used by laminating with paper or other resin layers that play a reinforcing role on the resin layer. There are many cases.

Patent Document 1 discloses a transparent polylactic acid film suitable as a packaging material for foods, pharmaceuticals and the like, and a laminated film material obtained by laminating a sealant on the film because it is easy to cut and easily peeled and opened. The invention is disclosed.
Patent Document 2 discloses a method for producing relatively deep-drawn containers such as cups using a polylactic acid resin while maintaining the original transparency and rigidity of the resin, and the method. Inventions of molded articles such as containers are disclosed.
Furthermore, in Patent Document 3, a polylactic acid resin-molded container is sealed with an easily peelable lid formed by laminating a polybutylene succinate layer and a polybutylene succinate / polyethylene composition layer on a polylactic acid resin base film. An invention of a biodegradable package body that is hermetically sealed is disclosed.

Japanese Patent Laid-Open No. 2004-256695 JP 2005-319718 A JP 2007-223201 A

In many containers used for various foods, beverages, cosmetics, etc., the contents are filled and then sealed with a lid or the like coated with a sealant, and the contents are taken out by peeling the seal lid or the like when used.
In order for the lid to be peeled smoothly when the contents are taken out, the adhesive strength between the container body and the lid needs to be moderate. If the adhesive strength is too strong, excessive peeling will occur. In the extreme case, the container body may be damaged or the lid may be torn off.If the adhesive strength is too weak, it will cause an extremely light impact during transportation and storage. When the lid is peeled off and dropped, or in extreme cases, the lid body may drop off naturally due to a slight impact or deformation due to temperature difference or its own weight.

Suitable adhesive strength depends on various external and internal conditions such as container size, weight, vibration intensity during storage and transportation, but it is easy to use for general food containers such as plastic containers such as yogurt and juice. In the case of a peeling lid, generally, an adhesive strength of about 3 N / 15 mm to 20 N / 15 mm (T-type peeling) is appropriate.
In addition, recently, it is possible to always peel at the interface without leaving a residue such as sealant at the time of peeling, that is, the feeling of peeling is good, that is, it can be peeled smoothly at an almost constant speed with an appropriate force, and at any time at a desired position. It has been demanded that peeling can be stopped and the state can be maintained.
Of course, the adhesive strength of the sealant differs depending on the type of base material to be bonded, and an appropriate sealant is selected according to the respective materials.

Conventionally, plastic materials that have been widely used have known sealants suitable for each, and the above-mentioned adhesive strength has been used without any particular problems.
However, a molded product having a polylactic acid resin molding or a polylactic acid resin layer on its surface, for example, a container made of a laminate having a polylactic acid resin layer on its surface, is a sealant used for it, and is problematic from the food hygiene aspect. However, it is still difficult to find one having the above-mentioned moderate adhesive strength and good peeling feeling, and this problem has not been completely solved yet.
Accordingly, there is a strong demand from the industry to provide such sealants.

  Therefore, as a result of intensive studies to meet the above-mentioned demands, the present inventors have found that an ethylene / unsaturated carboxylic acid copolymer and polyethylene, a specific ethylene polymer such as an ethylene / α-olefin copolymer, or a mixture thereof and an adhesive. The present inventors have found that a resin composition blended with a given resin in a specific amount ratio satisfies all the above requirements as a sealant for a polylactic acid resin molded body, and based on this finding, the present invention has been completed.

Accordingly, an object of the present invention is to have a moderately strong adhesiveness to a polylactic acid resin such as a polylactic acid resin container or a laminate container having a polylactic acid resin layer, and to give a good peeling feeling upon opening and peeling. To provide an easily peelable sealant.
Another object of the present invention is to provide a laminate or lid for sealing a polylactic acid resin container, a laminated container having the resin layer, etc., having the sealant layer as an easy-open adhesive layer.
Furthermore, another object of the present invention is to provide an easily openable sealed container of polylactic acid resin sealed with the above sealant.

  According to the present invention, 15 to 80 parts by weight of ethylene / unsaturated carboxylic acid copolymer (A), polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl ester copolymer and ethylene / unsaturated carboxylic acid ester copolymer 10-80 parts by weight of at least one resin (B) selected from polymers, 3-30 parts by weight of tackifier resin (C) (however, (A), (B), (C) total 100 parts by weight) The present invention relates to a sealant for polylactic acid resin comprising a resin composition.

  In the sealant of the present invention, 300 ppm to 10 parts by weight of at least one additive selected from aliphatic amide, fatty acid bisamide, polyethylene glycol, hydrogenated castor oil and silica is further blended with 100 parts by weight of the resin mixture. It is preferable to become.

In the present invention, the resin (B) is preferably a mixture of polyethylene and an ethylene / α-olefin copolymer.
In the present invention, the tackifying resin is at least one resin selected from aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, rosins, and styrene resins. It is preferable that

  Moreover, according to this invention, the laminated body or cover body which has said sealant layer is provided.

  The laminate or the lid is preferably in a form in which the sealant is laminated as a surface layer directly or via an intermediate layer on at least one surface of the base material layer.

  The substrate layer is preferably a layer made of one selected from paper, polyester resin film, nylon resin film, and polyolefin resin film.

  The intermediate layer may comprise at least one layer selected from aluminum, polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl ester copolymer, and ethylene / unsaturated carboxylic acid ester copolymer. preferable.

  Moreover, according to this invention, the molded object formed by heat-sealing the molded object which the surface at least consists of a polylactic acid resin with the sealant in any one of Claims 1-4 is provided. The molded body is preferably a container.

Furthermore, according to the present invention, the container body comprises a container body and a sealing material or a lid for sealing the container body, and the container body is a sealed container having at least a surface thereof made of polylactic acid resin.
A sealed container is provided in which the container body is sealed with the sealant of the present invention or the laminate or lid of the present invention.
The container body includes an embodiment in which a polylactic acid resin is surface-coated directly or via an intermediate layer on a paper substrate.

The sealant according to the present invention has a moderately strong adhesiveness to a polylactic acid resin surface such as a polylactic acid resin container or a laminate container having a polylactic acid resin layer, and the sealant is unsealed when opened. It is easy, and can be peeled off without leaving any residue on the adherend surface, giving a smooth and good peel feeling.
Therefore, it is useful as an easily peelable sealant for a molded body having a polylactic acid molded body or a polylactic acid resin at least on its surface. For example, an easily openable bag or container made of a polylactic acid resin, its sealing lid, etc. It can be suitably applied.
In addition, a molded product having at least a polylactic acid resin whose surface is sealed with a polylactic acid resin surface of the molded product using the sealant according to the present invention is excellent in content protection and is practically required for an easily openable container. It exhibits excellent performance as an easily peelable and openable packaging material that retains a suitable seal strength, is easy to open, gives a good peel feeling upon peeling, and has no sealant remaining in the opening.

Embodiments according to the present invention will be described in detail and specifically below.
As already mentioned, the sealant of the present invention comprises 15 to 80 parts by weight of ethylene / unsaturated carboxylic acid copolymer (A), polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl ester copolymer and ethylene / unsaturated copolymer. 10 to 80 parts by weight of at least one resin (B) selected from carboxylic acid ester copolymers, 3 to 30 parts by weight of tackifier resin (C) (however, (A), (B), (C) total 100) A sealant for a polylactic acid-based resin comprising a resin composition containing (part by weight).

In the resin composition constituting the sealant of the present invention (hereinafter sometimes simply referred to as sealant composition), one of the resin components (A) ethylene / unsaturated carboxylic acid copolymer is ethylene / unsaturated. Not only carboxylic acid binary copolymers but also ternary or higher terpolymers containing ethylene and unsaturated carboxylic acid components such as ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymers as essential polymerization components Includes coalescence.
The component (A) in the sealant of the present invention is more preferably a terpolymer such as an ethylene / unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer because the copolymer is more flexible. .

Examples of unsaturated carboxylic acids to be copolymerized with ethylene include acrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, fumaric acid, maleic acid, monomethyl maleate, maleic anhydride, itaconic acid and itaconic anhydride. can do.
Of these, acrylic acid or methacrylic acid is particularly preferred.

Examples of the unsaturated carboxylic acid ester include alkyl esters having 1 to 20 carbon atoms of the unsaturated carboxylic acid. More specifically, examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n Examples include alkyl groups such as -butyl, isobutyl, 2-ethylhexyl, isooctyl and the like.
Of these, alkyl esters of acrylic acid or methacrylic acid, particularly methyl, ethyl and isobutyl esters of acrylic acid or methacrylic acid are preferred.

The content of unsaturated carboxylic acid units in the copolymer is preferably 2 to 20% by weight.
Moreover, in the copolymer containing an unsaturated carboxylic acid ester component, the content of the ester unit is preferably 0 to 20% by weight.
Moreover, it is preferable that the melt flow rate (MFR) (190 degreeC 2160g load according to JISK7210) of this copolymer is 0.05-500 g / 10min, especially 0.2-300g / 10min.

In the present invention, the component (B) to be mixed with the component (A) was selected from polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl ester copolymer and ethylene / unsaturated carboxylic acid ester copolymer. One type or two or more types of resins are used.
The polyethylene preferably has a MFR (according to JIS K7210, 190 ° C., 2160 g load) in the range of 1 to 400 g / 10 minutes, and the others are not particularly limited, but the density is 905 to 930 kg / m ³ low density polyethylene The use of (LDPE) is more preferred.
Next, the α-olefin of the ethylene / α-olefin copolymer is propylene, butene-1, pentene-1, hexene-1, octene-1, 3-methylbutene-1, 3,3-dimethylbutene-1, 4-methyl. Pentene 1 etc. can be illustrated.
The ethylene / α-olefin copolymer used for the component (B) is preferably a low crystallinity or non-crystallinity rather than a high crystallinity, and its crystallinity is preferably 40% or less. The content of α-olefin units in the ethylene / α-olefin copolymer is preferably 1 to 20 mol%.
The MFR (compliant with JIS K7210 190 ° C., 2160 g load) is preferably in the range of 1 to 400 g / 10 min.
Examples of the vinyl ester of the ethylene-vinyl ester copolymer include vinyl acetate and vinyl propionate, and the vinyl ester unit content in the copolymer is preferably 2 to 45% by weight.
Further, the MFR of the ethylene-vinyl ester copolymer (according to JIS K7210, 190 ° C., 2160 g load) is preferably in the range of 1 to 400 g / 10 min.
Further, the unsaturated carboxylic acid ester component of the ethylene / unsaturated carboxylic acid ester copolymer is an unsaturated carboxylic acid / unsaturated carboxylic acid ester copolymer used in the component (A). Saturated carboxylic acid esters can be exemplified, and methyl acrylate, ethyl acrylate, isobutyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and the like are preferable. The carboxylic acid ester content in the copolymer is preferably 2 to 25% by weight.
The component resin (B) is not necessarily limited to one of the above polymers and copolymers, and a mixture of two or more may be used.
In particular, it is preferable to use a resin mixture having a weight ratio of 1: 4 to 4: 1 of the polyethylene and the ethylene / α-olefin copolymer as the component (B) from the viewpoint of sealing strength with the polylactic acid resin.

Examples of the tackifier resin used as the component (C) in the sealant composition of the present invention include aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, polyterpene resins, rosins, and styrene resins. Resin.
Examples of the aliphatic hydrocarbon resin include polymers mainly composed of C ₄ and / or C ₅ olefins such as butene, isobutylene, butadiene, and 1,3-pentadiene, and diolefins, and alicyclic hydrocarbons. Examples of the resin include a resin obtained by polymerizing a diene component in a spent C _{4 to} C ₅ fraction after cyclization and dimerization, a resin obtained by polymerizing a cyclic monomer such as cyclopentadiene, and an aromatic hydrocarbon resin. Examples thereof include resins added.
As the aromatic hydrocarbon resins, vinyl toluene, indene, resins composed mainly of vinyl aromatic hydrocarbon of C ₉ such as α-methylstyrene styrene can be exemplified.
Furthermore, specific examples of polyterpene resins include α-pinene polymers, β-pinene polymers, dipentene polymers, and terpene / phenol copolymers, and rosins include rosin, polymerized rosin, hydrogenated rosin, and rosin. Examples thereof include glycerin ester and hydrogenated product or polymer thereof, and pentaerythritol ester of rosin and hydrogenated product or polymer thereof.
Examples of the styrene resin include a polymer of a styrene monomer, a styrene / olefin copolymer, and a vinyltoluene / α-methylstyrene copolymer.
These tackifying resins preferably have a softening point in the range of 90 to 150 ° C.

In the sealant composition of the present invention, in addition to the essential resin components (A), (B), (C), saturated or unsaturated fatty acid amide, saturated or unsaturated fatty acid bisamide, polyethylene glycol, water It is preferable to add at least one additive selected from added castor oil and silica.
These specific additives prevent blocking when the sealant composition of the present invention is pelletized, and also prevent blocking between films or stake with metal rolls during extrusion processing and coating processing, Furthermore, the workability is improved when post-processes such as rewinding, slitting, bag making, punching, filling, etc. are required.

As the saturated or unsaturated fatty acid amide, amides of C ₈ to C ₂₂ saturated linear fatty acids and monounsaturated fatty acids are preferable. Specifically, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid Examples thereof include amides, erucic acid amides, and mixtures thereof.
Furthermore, secondary amides such as oleyl palmitoamide and stearyl erucamide can also be used as the fatty acid amide.
The saturated or unsaturated fatty acid bisamide is mainly composed of C ₈ to C ₂₂ N, N′-methylene bisamide or N, N′-ethylene bisamide, and among them, stearic acid and behenic acid. Methylene bisamides such as oleic acid and erucic acid and ethylene bisamides such as stearic acid, behenic acid, oleic acid and erucic acid are preferred.

  The amount of these additives is suitably 300 ppm to 10 parts by weight with respect to 100 parts by weight of the total amount of the essential components (A), (B), and (C), and particularly saturated or unsaturated fatty acid amide, saturated or In the case of unsaturated fatty acid bisamide, polyethylene glycol, and hydrogenated castor oil, 300 to 10000 ppm is preferable, and in the case of silica, 0.1 to 3 parts by weight is preferable.

In the sealant composition of the present invention, the above (A), (B), (C) each essential component needs to be within the following blending ratio range ((A), (B), (C) total = 100%).
(A) Component 15 to 80% by weight
(B) Component 10 to 80% by weight
(C) Component 3 to 30% by weight
When the blending amount of the component (A) is less than 15% by weight, it is difficult to ensure smooth peeling at the resin interface when heat-sealing to the polylactic acid resin which is the resin to be sealed of the present invention, and 80% by weight. When more, compatibility with the tackifier resin which is (C) component falls, and all are unpreferable.
On the other hand, when the blending amount of the component (B) is less than 10% by weight, the compatibility with the component (C) (tackifying resin) is poor, and when it is greater than 80% by weight, the seal part is broken. Neither is preferred.
Further, when the blending amount of the component (C) is less than 3% by weight, the adhesion strength to the polylactic acid resin is weak, and when it is more than 30% by weight, it is too strong and the blocking becomes remarkable. In the present invention, it is particularly preferable to use polyethylene (b1) and (b2) a low crystalline or non-crystalline ethylene-α-olefin copolymer as the component (B). In this case, each component is within the following blending ratio range. Preferably there is.
(A) Component 15 to 80% by weight
(B1) Component 2 to 64% by weight
(B2) component 64-2 weight%
(C) Component 3 to 30% by weight
(However, the total amount of (A), (b1), (b2) and (C) is 100% by weight, and the total amount of (b1) and (b2) is 10 to 80% by weight)

In order to obtain the sealant composition of the present invention, the above-mentioned components (A), (B), and (C) are blended with additives such as the fatty acid amide, if desired, and mixed simultaneously or sequentially.
As the mixing method, a method of melt mixing using a single screw extruder, a twin screw extruder, a Banbury mixer or various kneaders is preferable, and there is no particular limitation on the mixing order.
The sealant composition of the present invention preferably has a melt flow rate (MFR) in the range of 1 to 400 (g / 10 minutes) after mixing and melting and kneading the above-mentioned components.
When the MFR of the composition is 1 or less, the viscosity is too high and the resin pressure is increased, and the motor load is increased, resulting in difficulty in extrusion moldability and coating workability. Sex is inhibited and neither is preferred.
When the sealant composition of the present invention is formed by extrusion coating, the MFR is preferably in the range of 1 to 150 g / 10 minutes from the viewpoint of moldability, and when coated with a high viscosity coater, the MFR is preferably used. Is preferably in the range of 50 to 400 g / 10 min.

The above-mentioned sealant composition of the present invention can be formed into a film by a method such as inflation or T-die casting, or polyethylene, polypropylene, an ethylene / vinyl acetate copolymer, an ethylene / methacrylic acid copolymer or its ionomer, A coextruded film may be formed by coextrusion inflation molding or coextrusion cast molding with a suitable other resin such as nylon, polyester or polystyrene.
The single film thus obtained can be used as it is as a sealing agent for a polylactic acid resin molded body, and in the case of a coextruded film, the sealant layer of the present invention is used as a heat seal layer to form a polylactic acid resin molded body. Used as a sealing laminate or a sealing lid.

Further, the above single film or coextruded film is dry-laminated with a stretched or unstretched film or sheet of polypropylene resin, nylon resin, polyester resin, aluminum foil, cellophane, paper, or other composite film or sheet. Alternatively, a laminate or lid for sealing the polylactic acid resin molded body can be produced by sandwich lamination.
In addition, the sealing laminate or lid body obtained by coating the sealant composition of the present invention on a substrate such as paper, paperboard, aluminum foil, various plastic films, and sheets by extrusion coating, roll coating, cast coating or the like. It can be.
Furthermore, it can also apply | coat with respect to various base materials with high-viscosity coaters, such as a gravure roll coat system and a cast coat system, and can also be laminated | stacked.

As an example of a laminated structure of the polylactic acid resin molded body sealing laminate or lid, for example,
Base material layer / sealant layer such as paper, PET, nylon, base material layer / polyethylene layer (intermediate layer) / sealant layer, sealant layer / base material layer / sealant layer, sealant layer / intermediate layer / base material layer / intermediate layer / Sealant layer.
In the laminate having the above layer structure, examples of the base material layer include paper, polyester resin film, nylon resin film, polyolefin resin film, and the like. Examples of materials used as the intermediate layer include aluminum and polyethylene. And ethylene / α-olefin copolymers, ethylene / vinyl ester copolymers, and ethylene / unsaturated carboxylic acid ester copolymers.

As already stated, the sealant of the present invention is a polylactic acid in a molded body having at least the surface of a polylactic acid resin such as a polylactic acid resin container or a laminated container having a polylactic acid resin layer as a single film, a laminated body or a lid. By heat sealing the resin surface, it is applied to sealing of the molded body, particularly easy-opening sealing.
In the present invention, the polylactic acid resin means polylactic acid which is a polymer of lactic acid or a lactic acid copolymer mainly composed of lactic acid, for example, lactic acid / hydroxycarboxylic acid copolymer or lactic acid / aliphatic polyvalent resin. Of course, an alcohol / aliphatic polybasic acid copolymer and the like correspond to this, and further include a resin composition containing the polymer and / or copolymer as a main component.
As an example of such a resin composition, for example, a polylactic acid polymer and / or a copolymer is a main component, and a polyethylene, an ethylene / unsaturated carboxylic acid copolymer, its ionomer, an ethylene / vinyl acetate copolymer Examples of the resin composition include a polymer, an ethylene polymer such as an ethylene / unsaturated carboxylic acid ester copolymer, and other polyolefins.

Further, in the case of a molded body such as a container composed of a laminate including a polylactic acid resin layer, as an example of the laminate configuration, for example,
Base layer of paper, PET, nylon, polypropylene, etc./polylactic acid resin layer, base material layer / intermediate layer such as Al foil / polylactic acid resin layer, polylactic acid resin layer / base material layer / polylactic acid resin layer, polylactic acid Examples of the layer structure include resin layer / intermediate layer / base material layer / intermediate layer / polylactic acid resin layer.
The sealed container of the aspect in which the container body is formed by coating the surface of polylactic acid resin directly or through an intermediate layer on a paper substrate with the laminated lid of the present invention is excellent in content protection. It retains the suitable seal strength required for an easily openable container, yet it is easy to open, gives a good feeling of peeling upon peeling, and exhibits excellent performance without leaving a sealant at the opening.

  The easy-open polylactic acid resin sealed container of the present invention is a laminate or lid having the sealant single film or sealant surface layer of the present invention, and the opening of the laminate container main body having the polylactic acid resin container body or polylactic acid resin layer. For example, a heat sealer is used for the part, and heat sealing is performed under appropriate pressure and heating conditions.

剥離強度測定条件：剥離速度300ｍｍ／分、T型剥離
ヨーグルトやジュース等を充填した紙コップ等の易開封性容器の容器蓋に於ける剥離強度は一般に３〜２０Ｎ／１５ｍｍ程度が適正値とされており、表１の結果から、本発明に係るシーラントは乳酸樹脂表面に対し適正な接着性を示すことが判る。 Example 1
Ethylene / methacrylic acid / isobutyl acrylate terpolymer (A) (methacrylic acid content 10 wt%, isobutyl acrylate content 10 wt%, MFR 36 g / 10 min) 48 parts by weight, low density polyethylene (trade name: 16 SPO, Prime Polymer Co., Ltd., density 923 kg / m ³ , MFR 4.5 g / min) 26 parts by weight and low crystalline α-olefin copolymer (trade name: Toughmer A4085, Mitsui Chemicals, Inc.) 10 weight Resin mixture (B) (36 parts by weight) and tackifier resin (C) (hydrogenated aromatic hydrocarbon resin, ring and ball method softening point; 115 ° C .: product name: Alcon AM1: Arakawa Chemical Co., Ltd. ) 16 parts by weight, and 8000 ppm of slip agent (N-oleyl palmitoamide: manufactured by Nippon Seika Co., Ltd.) and release agent (behenic acid amide: Wit) Added o Ltd.) 3000 ppm was melt-kneaded at 140 ° C. in an extruder, and pelletized.
The MFR of this composition was 32 g / 10 minutes.
In this example, MFR was measured under the conditions of 190 ° C. and 2160 g load according to JIS K7210.
Next, this composition was subjected to extrusion laminating at a processing temperature of 250 ° C. and a processing speed of 80 m / min, and a piece of art paper (79.1 g / m ² ) / polyethylene layer (LDPE 20 μm) / aluminum foil (Al 7 μm) / composition. A layered product (25 μm) was obtained.
Next, the sample film was placed on a 35 mm-thick polylactic acid resin sheet (manufactured by Chuo Chemical Co., Ltd.) and heated under the conditions shown in Table 1 under a seal (gauge) pressure of 0.3 MPa and a seal time of 1.0 second. The laminate was obtained by sealing.
The peel strength when the sample film portion was peeled from this laminate was measured.
The results are shown in Table 1.

Peel strength measurement conditions: Peeling speed 300mm / min, T-type peel Peel strength at the lid of easy-open containers such as paper cups filled with yogurt or juice is generally 3-20N / 15mm. From the results shown in Table 1, it can be seen that the sealant according to the present invention exhibits appropriate adhesion to the lactic acid resin surface.

Claims (12)

  15 to 80 parts by weight of ethylene / unsaturated carboxylic acid copolymer (A), selected from polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl ester copolymer and ethylene / unsaturated carboxylic acid ester copolymer Resin composition comprising 10-80 parts by weight of at least one resin (B) and 3-30 parts by weight of tackifier resin (C) (however, (A), (B), (C) total 100 parts by weight) A sealant for polylactic acid resin.   2. The composition according to claim 1, further comprising 300 ppm to 10 parts by weight of at least one additive selected from aliphatic amide, fatty acid bisamide, polyethylene glycol, hydrogenated castor oil, and silica, based on 100 parts by weight of the resin composition. Sealant.   The sealant according to claim 1 or 2, wherein the resin (B) comprises a mixture of polyethylene and an ethylene / α-olefin copolymer.   The tackifying resin (C) is at least one resin selected from an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin, an aromatic hydrocarbon resin, a polyterpene resin, a rosin, and a styrene resin. The sealant according to any one of claims 1 to 3.   The laminated body or cover body which has the layer of the sealant in any one of Claims 1-4.   The laminate or lid according to claim 5, wherein the sealant is laminated as a surface layer directly or via an intermediate layer on at least one surface of the base material layer.   The laminate or lid according to claim 6, wherein the base material layer is a layer made of one selected from paper, a polyester resin film, a nylon resin film, and a polyolefin resin film.   8. The intermediate layer is made of at least one layer selected from aluminum, polyethylene, ethylene / α-olefin copolymer, ethylene / vinyl ester copolymer and ethylene / unsaturated carboxylic acid ester copolymer. The laminated body or lid body as described.   A molded article obtained by heat-sealing a molded article having at least a surface thereof made of a polylactic acid resin with the sealant according to any one of claims 1 to 4.   The molded body according to claim 9, wherein the molded body is a container. It consists of a container body and a sealing material or a lid for sealing it, and the container body is a sealed container having at least a surface thereof made of polylactic acid resin.
The said container main body polylactic acid resin is sealed with the sealant in any one of Claims 1-4, or the laminated body or lid in any one of Claims 5-8, The sealed container characterized by the above-mentioned. .   The container according to claim 10, wherein the container body is formed by coating a surface of a paper base material with a polylactic acid resin directly or via an intermediate layer.