JP2007181943A - Laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate manufactured by providing at least an adhesive layer and a sealant layer on a plastic base material in this order, having excellent lamination strength, not lowered in the lamination strength between the plastic base material and the sealant layer even if a volatile component or various strong permeable contents act and also having biodegradability. <P>SOLUTION: The laminate comprises at least the adhesive layer and the sealant layer provided on the plastic base material in this order, wherein the adhesive layer has a thickness of 1 μm or below, and forms a laminated structure of a first adhesive layer comprising an amine-containing polymer and a second adhesive layer comprising an isocyanate compound. The plastic base material and the sealant layer comprise at least an aliphatic polyester or an alaromatic polyester. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a laminate in which at least an adhesive layer and a sealant layer are provided in this order on a plastic substrate, and in particular, various laminates having excellent laminate strength and containing volatile components and volatile components. The present invention relates to a laminated body characterized in that the laminate strength between a plastic substrate and a sealant layer does not decrease even when a strongly permeable substance acts, and further has biodegradability.

  Conventionally, as a packaging material for packaging foods and pharmaceuticals, for example, at least an adhesive layer and a sealant layer are formed on a plastic substrate having a configuration such as a paper layer / polyethylene layer / aluminum foil layer / polyester layer / sealant layer. Laminated bodies laminated in this relative order have been widely used. The lamination of the polyester layer (plastic substrate) and the sealant layer of the laminate having such a structure is usually performed by applying a two-component curable polyurethane anchor coating agent or the like to the polyester layer made of a polyester film. This was done by extrusion laminating the sealant layer. And such a laminated body has moderate lamination strength, gas barrier property, etc., and is widely used as a packaging material for packaging foods and pharmaceuticals.

  However, many of the contents packaged by the packaging material contain an alkaline substance, a fragrance, a surfactant, a high boiling point organic solvent, etc., and these contents are packaged by a laminate having the above-described configuration. As a result, the adhesive constituting the adhesive layer is adversely affected, leading to a decrease in laminate strength in the laminate or peeling.

  In order to cope with this situation, various improvements have been made to the adhesive used for laminating, improving the resistance to highly alkaline contents, and further improving the adhesion to various plastic films. Various agents have been proposed (see, for example, Patent Document 1).

  However, when the content to be packed is a poultice or a bath preparation, since these contain volatile substances, the laminated body having the above-described structure or the laminated layer formed via the anchor coating agent is used. When the body is used as a packaging material and these contents are packaged, the strong penetration of volatile substances reduces the laminate strength between the plastic substrate and the sealant layer over time, resulting in delamination. There was a thing.

  Such delamination is an adhesive layer made of a two-component curable polyurethane adhesive in which a main component such as polyester polyol and a curing agent made of an isocyanate compound are blended, for example, used for laminating the above laminate. It is thought that this occurs when the strongly penetrating contents adversely affect the main component resin component of the adhesive layer and cause a decrease in molecular weight, thereby reducing the cohesive force of the adhesive layer.

Under such circumstances, in a laminate in which a sealant layer is provided on at least an adhesive layer on a plastic substrate, even if various strongly penetrating substances including volatile components and volatile components act on the laminate. Therefore, there has been a strong demand for the development of a laminate that can be suitably used for packaging materials, in which the laminate strength between the plastic substrate and the sealant layer does not decrease.
JP-A-10-130615

  The present invention has been made in order to solve the above-described conventional problems, and an object thereof is a laminate in which at least an adhesive layer and a sealant layer are provided in this order on a plastic substrate. In addition, it has excellent laminate strength, and even when various permeable components containing volatile components or volatile components act, the laminate strength between the plastic substrate and the sealant layer does not decrease and is biodegradable. It is providing the laminated body which also had.

  In order to solve the above problems, the invention according to claim 1 is characterized in that at least an adhesive layer and a sealant layer are provided in this order on a plastic substrate, and the adhesive layer has a thickness of 1 μm or less, In addition, the first adhesive layer made of an amine-containing polymer and the second adhesive layer made of an isocyanate compound are laminated, and the plastic substrate and the sealant layer are made of at least an aliphatic polyester or an aliphatic aromatic polyester. It is the laminated body characterized by these.

  The invention described in claim 2 is characterized in that, in the laminate according to claim 1, an easy adhesion treatment layer is formed on the side of the plastic substrate on which at least the adhesive layer is provided. To do.

  Furthermore, the invention according to claim 3 is the laminate according to claim 2, wherein the easy adhesion treatment layer is one of an easy adhesion treatment of corona treatment, low pressure plasma treatment, atmospheric pressure plasma treatment, or flame treatment. It is formed by these.

  The laminate of the present invention is composed of at least four layers of a plastic substrate, a first adhesive layer made of an amine-containing polymer, a second adhesive layer made of an isocyanate compound, and a sealant layer, and the first adhesive layer, Since the second adhesive layer is not affected by the strongly permeable content, and the adhesive layer that is composed of these two layers is very thin and dense, it exhibits excellent laminate strength with respect to the plastic substrate. Therefore, for example, even when used as a packaging material for storing various strongly permeable contents such as poultices and bathing agents, the laminate strength between the plastic substrate and the sealant layer does not decrease, and delamination does not occur. Furthermore, since the plastic substrate and the sealant layer are aliphatic polyester or aliphatic aromatic polyester, they also have a biodegradation function.

  Hereinafter, embodiments of the present invention will be described in detail.

  In the laminate of the present invention, at least an adhesive layer and a sealant layer are provided in this order on a plastic substrate, and the adhesive layer has a thickness of 1 μm or less and a first adhesive layer made of an amine-containing polymer and an isocyanate. The laminate has a laminated structure with a second adhesive layer made of a compound, and the plastic substrate and the sealant layer are made of at least an aliphatic polyester or an aliphatic aromatic polyester.

The plastic substrate constituting such a laminate is made of an aliphatic polyester or an aliphatic aromatic polyester, and is preferably a transparent film substrate if possible in order to make use of the transparency of the laminate. Specific examples of the constituent material include a polymer containing lactic acid as a main component, for example, a homopolymer consisting only of lactic acid, a monomer other than lactic acid as a main component, such as oxyacids such as malic acid and glycolic acid, 3- Examples include copolymers obtained by copolymerizing hydroxybutyrate, 3-hydroxyvalylate, caprolactone, dicarboxylic acids such as succinic acid and adipic acid, and diols such as ethylene glycol and 1,4-butanediol, and mixtures thereof. It is done. Among these, homopolymers composed only of lactic acid are preferably used because they are excellent in transparency.

  Copolymers of dicarboxylic acids such as succinic acid, adipic acid and terephthalic acid and diols such as ethylene glycol and 1,4-butanediol, such as polyethylene terephthalate-succinate having terephthalic acid, polybutylene adipate-terephthalate Polytetramethylene adipate-terephthalate can also be preferably used because of its excellent transparency.

  An easy adhesion treatment layer is provided by an easy adhesion treatment on at least the surface of the plastic substrate having such a configuration on which the adhesion layer is laminated. Specifically, the easy adhesion treatment layer is formed on the surface of the plastic substrate by surface treatment such as corona treatment, low-pressure plasma treatment, atmospheric pressure plasma treatment, flame treatment, and the like. It is a processing layer provided so that the contact bonding layer can be formed stably. In particular, when the above-described easy adhesion treatment is performed, the amount of polar groups present on the surface of the plastic substrate increases, so that the adhesion with the adhesive layer becomes stronger. There is no particular limitation on the thickness of the layer and the way of surface treatment.

  On the other hand, the adhesive layer laminated on the easy adhesion treatment layer has a thickness of 1 μm or less and a first adhesive layer made of an amine-containing polymer and a second adhesive layer made of an isocyanate compound, as described above. It is the laminated constitution of.

  By making the configuration of the adhesive layer into a two-layer configuration of the first adhesive layer and the second adhesive layer, the first adhesive layer acts to firmly adhere to the surface of the plastic substrate. The adhesive layer causes a cross-linking reaction with the first adhesive layer, and the cross-linking reaction product acts to firmly adhere to both the surface of the plastic substrate and the surface of the sealant layer described later. Even if various strongly permeable substances including volatile substances such as fragrance ingredients and volatile substances act on the laminate of the present invention, the laminate strength between the plastic substrate and the sealant layer does not decrease, Thus, it is possible to maintain the desired adhesiveness of the strongly permeable contents.

  The amine-containing polymer constituting the first adhesive layer may be a polymer having an amino group such as a primary amine, a secondary amine, or a tertiary amine. For example, a polymer having polyethyleneimine and an ethyleneimine chain in the side chain. Any of water-based or solvent-based materials can be used. Among them, those having a number average molecular weight of about 10,000 to 100,000 are preferably used.

  Examples of the isocyanate compound constituting the second adhesive layer include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and 4,4′-diphenylmethane diisocyanate. And various diisocyanate monomers such as hydrogenated products thereof. In addition, adduct types obtained by reacting these diisocyanate monomers with trifunctional active hydrogen-containing compounds such as trimethylolpropane and glycerol, burette types obtained by reacting with water, and trimers utilizing self-polymerization of isocyanate groups ( A trifunctional derivative such as an isocyanurate type or a polyfunctional derivative higher than that may be used.

Each adhesive layer having such a structure is coated with a coating liquid containing the above-described amine-containing polymer or isocyanate compound in a solid content ratio of 0.05 to 5 wt%, preferably 0.1 to 2 wt%. Should be provided. Further, the total thickness of each of these adhesive layers is preferably thin, and specifically, it may be provided such that the total thickness when dried is a thin layer of 1 μm or less. 1
If it exceeds μm, it takes time for drying to fly away the solvent, and it takes time for the reaction of the adhesive layer.

  Further, the sealant layer provided on the second adhesive layer of the adhesive layer having a two-layer structure is composed of at least an aliphatic polyester or an aliphatic aromatic polyester. This sealant layer is a layer provided for imparting a function such as heat sealability to the laminate. As a material constituting the sealant layer, a copolymer of a dicarboxylic acid such as succinic acid or adipic acid and a diol such as ethylene glycol or 1,4-butanediol (for example, polyethylene succinate, polybutylene succinate, Polybutylene succinate-adipate), microbial-produced polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate-hexanoate, polymers of oxyacids such as lactic acid, malic acid, glycolic acid or their co-polymers Polyester, polycaprolactone, polycaprolactone-butylene succinate, aliphatic polyester such as polyester having amide bond, polyester having carbonate bond, or polyethylene terephthalate-succine having terephthalic acid , Polybutylene adipate - terephthalate, polytetramethylene adipate - terephthalate and alone or two or more of the blend of resin selected from the aliphatic-aromatic polyesters, and the like. You may add various additives (Antioxidant, a tackifier, a filler, various fillers, etc.) to these structural materials as needed.

  In the laminate of the present invention, each constituent layer of the plastic substrate and the sealant layer is an aliphatic polyester or an aliphatic aromatic polyester, so that not only the strong permeable content resistance but also the biodegradation function is provided. You will have both. At this time, the adhesive layer existing between the plastic substrate and the sealant layer does not have biodegradability, but the adhesive layer is a very thin layer having a thickness of 1 μm or less, so that the biodegradability of the laminate is inhibited. There is no.

  The laminated body according to the present invention has been described above, but the laminated body of the present invention is not limited to the structure as described above, and the rigidity required as a packaging material in consideration of the use as a packaging material. For the purpose of improving the durability and the like, another layer may be interposed.

  A laminated body having such a configuration can be produced, for example, as follows. That is, a coating containing an amine-containing polymer in a solid content ratio of 0.05 to 5 wt%, preferably about 0.1 to 2 wt%, on the surface of the plastic substrate that has been subjected to surface treatment such as corona treatment. The working solution is applied by a coating method such as gravure coating or roll coating, and sufficiently dried to provide the first adhesive layer. Next, a coating solution containing an isocyanate compound in a solid content ratio of 0.05 to 5 wt%, preferably about 0.1 to 2 wt% is applied onto the first adhesive layer by gravure coating, roll coating or the like. It coats by a construction method, fully dries and laminates the 2nd adhesion layer, and provides the adhesion layer used as the 2 layer composition of the 1st adhesion layer and the 2nd adhesion layer.

  Finally, a sealant layer made of, for example, polybutylene succinate is laminated on the adhesive layer by an extrusion laminating method, a thermal laminating method, or the like, and a laminated structure of a plastic base material / adhesive layer / sealant layer composed of two layers Can be obtained.

  According to the manufacturing method as described above, the laminate strength between the plastic base material and the sealant layer is good, and the plastic base material and the sealant can be used even when various strongly permeable contents including volatile substances and volatile substances act. A laminate in which the laminate strength with the layer does not decrease can be produced. Examples of the present invention will be described below.

As a plastic substrate, a biaxially stretched polylactic acid film having a thickness of 25 μm and subjected to corona treatment on one surface, polyethyleneimine having a number average molecular weight of 50,000 on the corona-treated surface, and a solid content ratio of 1 wt% The coating solution prepared so as to be applied was applied by a roll coater and sufficiently dried to provide a first adhesive layer.

  Subsequently, a polybutylene succinate having a thickness of 40 μm was applied on the first adhesive layer while applying a coating solution prepared by adding an adduct type of tolylene diisocyanate to a solid content ratio of 1 wt%. After extruding by an extrusion laminating method at 80 m / min to laminate the second adhesive layer and the sealant layer, the laminate was aged at 50 ° C. for 3 days to obtain a laminate according to Example 1. The total thickness of the first adhesive layer and the second adhesive layer at this time was 0.16 μm.

  A laminate according to Example 2 was obtained in the same manner as in Example 1 except that an aqueous primary amine-grafted acrylic polymer having a number average molecular weight of 100,000 was used as the constituent material of the first adhesive layer.

  A laminate according to Example 3 was obtained in the same manner as in Example 1 except that a solvent-based primary amine-grafted acrylic polymer having a number average molecular weight of 100,000 was used as the constituent material of the first adhesive layer.

  A biaxially stretched polylactic acid film having a thickness of 25 μm and subjected to low-pressure plasma treatment on one surface as a plastic substrate, and a solvent-based primary amine-grafted acrylic polymer having a number average molecular weight of 100,000 as a constituent material of the first adhesive layer The laminate according to Example 4 was obtained in the same manner as in Example 1 except that the adduct type of isophorone diisocyanate was used as the constituent material of the second adhesive layer, and polyhydroxybutyrate was used as the constituent material of the sealant layer. It was.

  A biaxially stretched polyethylene terephthalate-succinate film having a thickness of 25 μm and subjected to atmospheric pressure plasma treatment on one surface as a plastic substrate, a solvent-based primary amine having a number average molecular weight of 100,000 as a constituent material of the first adhesive layer The laminate according to Example 5 was prepared in the same manner as in Example 1, except that the graft acrylic polymer, isophorone diisocyanate monomer as the constituent material of the second adhesive layer, and polyethylene succinate as the constituent material of the sealant layer were used. Obtained.

  A biaxially stretched polyethylene terephthalate-succinate film having a thickness of 25 μm with a frame treatment on one surface as a plastic substrate, and a water-based primary amine-grafted acrylic polymer having a number average molecular weight of 100,000 as a constituent material of the first adhesive layer In Example 6, except that hexamethylene diisocyanate burette type was used as the constituent material of the second adhesive layer and polybutylene succinate-adipate was used as the constituent material of the sealant layer. Such a laminate was obtained.

  A biaxially stretched polyethylene terephthalate-succinate film having a thickness of 25 μm with corona treatment on one side as a plastic substrate, an adduct type of xylylene diisocyanate as a constituent material of the second adhesive layer, and a constituent material of the sealant layer A laminate according to Example 7 was obtained in the same manner as in Example 1 except that polybutylene adipate-terephthalate was used.

  A biaxially stretched polylactic acid film having a thickness of 25 μm and subjected to corona treatment on one side as a plastic substrate is used, and a two-component curable polyurethane adhesive is applied to this corona-treated surface, and the solid content ratio becomes 1 wt%. The polybutylene succinate having a thickness of 40 μm was extruded by an extrusion laminating method at a processing speed of 80 m / min while laminating the adhesive layer and the sealant layer, and then aging at 50 ° C. for 3 days. And the laminated body which concerns on Example 8 for a comparison was obtained. The thickness of the adhesive layer at this time was 0.15 μm.

  A laminate according to Example 9 for comparison was obtained in the same manner as in Example 8 except that polyhydroxybutyrate was used as the sealant layer.

  A biaxially stretched polyethylene terephthalate film having a thickness of 12 μm and subjected to corona treatment on one side as a plastic base material was used in the same manner as in Example 1 except that polyethylene was used as a constituent material of the sealant layer. A laminate according to Example 10 was obtained.

  Table 1 summarizes the constituent materials of the constituent layers of the laminates according to Examples 1 to 10 obtained as described above.

次に、叙述の実施例１〜１０に係るそれぞれの積層体を用いてパウチを作製し、内容物として湿布薬（揮発性の強浸透性物質としてサリチル酸メチルやメントールを含有）と、浴用剤（揮発性の強浸透性物質として香料成分を含有）をそれぞれに充填、密封してから、４０℃の恒温室内に放置した。

Next, a pouch is prepared using each of the laminates according to Examples 1 to 10 described above, and a poultice (containing methyl salicylate and menthol as a volatile strong penetrating substance) as a content and a bath preparation ( Each was filled with a fragrance component as a volatile strong penetrating substance and sealed, and then left in a constant temperature room at 40 ° C.

  After the elapse of 3 months, these pouches were taken out from the thermostatic chamber, and the laminate strength [N / 15 mm] between various plastic substrates and the sealant layer of each pouch was measured and compared with the laminate strength in the pouch before entering the thermostatic chamber. The measurement conditions of the laminate strength at this time were T-type peeling with a sample width of 15 mm and a peeling speed of 300 mm / min. Table 2 summarizes the measurement results of the laminate strength before and after the constant temperature input.

  Next, the biodegradability test was performed by burying each laminated body of Examples 1-10 obtained as mentioned above in a 40 degreeC compost for 6 months. The laminate after the test was observed, and the evaluation was made with ○ indicating that it was decomposed so that it could not be identified, and × indicating that the shape was maintained without decomposition. The results are summarized in Table 2.

表２からも明らかなように、実施例１〜７に係る積層体を使用して作製されたパウチの各種プラスチック基材とシーラント層間におけるラミネート強度は、揮発性物質を含む湿布薬や浴用剤を入れて４０℃で３ヵ月間保存してもほとんど変わらず、初期のラミネート強度を十分に保っている。また、４０℃の堆肥中に６ヵ月間埋設した積層体は、判別が不可能なほど分解していた。

As is clear from Table 2, the laminate strength between the various plastic substrates and the sealant layers of the pouches produced using the laminates according to Examples 1 to 7 is a poultice or a bath agent containing a volatile substance. Even when stored at 40 ° C. for 3 months, the initial laminate strength is sufficiently maintained. Moreover, the laminated body embedded for 6 months in the compost of 40 degreeC was decomposed | disassembled so that discrimination | determination was impossible.

On the other hand, the pouch produced using the laminates according to Examples 8 to 9 having a single-layer adhesive layer made of two-component curable polyurethane has an initial laminate strength that is strong enough to show that the sealant is broken. However, after storing for 3 months at 40 ° C. with a poultice or bathing agent containing volatile substances, the laminate strength has dropped significantly to 2 [N / 15 mm] or less. It has been found that it is not suitable for use as a packaging material for packaging contents containing volatile substances such as bath agents. Moreover, in the laminated body which concerns on Example 10 whose plastic base material and sealant layer are both non-biodegradable, even if it embedded in a 40 degreeC compost | manure for 6 months, it maintained the shape as it is, without decomposing | disassembling.

Claims (3)

  At least an adhesive layer and a sealant layer are provided in this order on a plastic substrate, the adhesive layer has a thickness of 1 μm or less, and a first adhesive layer made of an amine-containing polymer and a second adhesive layer made of an isocyanate compound And a plastic substrate and a sealant layer are made of at least an aliphatic polyester or an aliphatic aromatic polyester.   The laminate according to claim 1, wherein an easy adhesion treatment layer is formed on at least a side of the plastic substrate on which the adhesive layer is provided.   The laminate according to claim 2, wherein the easy adhesion treatment layer is formed by any one of a corona treatment, a low pressure plasma treatment, an atmospheric pressure plasma treatment, and a flame treatment.