JP5320838B2 - Laminated body - Google Patents

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 strengths having excellent laminate strength and containing volatile substances. The present invention relates to a laminate in which the laminate strength between the plastic substrate and the sealant layer does not decrease even when the permeable content acts.

  Conventionally, as a packaging material for packaging foods and pharmaceuticals, for example, a laminate in which layers such as paper layer / polyethylene layer / aluminum foil layer / polyester layer / sealant layer are laminated has been widely used. The polyester layer (plastic base material) and sealant layer of this laminate are usually bonded to a polyester layer made of a polyester film after applying an anchor coating agent such as a two-component curable polyurethane as an adhesive layer. This was done by extrusion laminating the layers. 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, when the contents packed by the packaging material contain volatile substances such as acidic substances, alkaline substances, fragrances, surfactants, organic solvents, etc., anchors such as the above-described two-component curable polyurethane system When these contents are packaged using a laminate obtained by using a coating agent as a packaging material, the anchor coating agent is adversely affected by the strong penetration of volatile substances, resulting in a laminate between the plastic substrate and the sealant layer. The strength decreased with time, and as a result, delamination could occur.

  Such delamination is applied to an adhesive layer made of a two-component curable polyurethane system in which a main agent such as polyester polyol and a curing agent made of an isocyanate compound are blended with an anchor coating agent used when laminating the above laminate. This is considered to occur when the strongly penetrating contents adversely affect the main resin component of the adhesive layer and reduce the molecular weight, resulting in a decrease in the cohesive force of the adhesive layer.

  Under such circumstances, in a laminate in which a sealant layer is provided on a plastic substrate through at least an adhesive layer, even if various strongly permeable contents containing a volatile substance act, 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 material and the sealant layer does not decrease.

  Accordingly, various studies have been made on an anchor coating agent as an adhesive layer used in laminating, and at least an adhesive layer and a sealant layer are provided in this order on a plastic substrate, and the adhesive layer is a polyester polyol. It is a laminate using a two-component curable polyurethane system in which a curing agent composed of a main agent and an isocyanate compound is blended, and the ratio of the main agent and the curing agent is 1:99 to 15:85, and is particularly excellent. A laminate having a laminate strength that does not decrease the laminate strength between the base material and the sealant layer even when various strongly permeable contents containing a volatile substance act has been proposed (for example, Patent Documents). 1).

However, when the adhesive layer is rich in an isocyanate compound, an unreacted isocyanate group always remains after lamination. The urethane bond formed by the reaction between the hydroxyl group derived from the main agent and the isocyanate group derived from the curing agent has a relatively high formation rate, so that a stable laminate strength is manifested by short-term aging after the lamination process. Since the urea bond formed by this reaction has a very slow formation rate, heat aging for several days or more after laminating was indispensable. In addition, since the remaining unreacted isocyanate group reacts with water depending on the environment, sufficient lamination strength may not be exhibited even after several days of heat aging after lamination. It was.
JP 2006-187908 A

  The present invention has been made in order to solve the above-mentioned problems, and the object of 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. In particular, the laminate strength between the plastic substrate and the sealant layer does not decrease even when various strong penetrating substances having excellent laminate strength and containing volatile substances act. It is an object of the present invention to provide a laminate having a sufficient laminate strength that is stable by short-time room temperature aging and does not require heat aging for several days.

The invention according to claim 1 of the present invention, which was made to solve the above problems,
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 the adhesive layer has an isocyanate compound having a bifunctional or higher functional isocyanate group of 85% by weight or more; 0.01 to 0.5 wt% of tri -n- propylamine or tri -n- butylamine Tona is,
The initial laminating strength between the plastic substrate and the sealant layer is 4.6 N / 15 mm to 5 in a measurement condition in which aging is performed at 25 ° C. for 12 hours, and T-type peeling with a sample width of 15 mm and peeling speed is 300 mm / min a laminate which is characterized in .8N / 15mm der Rukoto.

  In the invention according to claim 2 of the present invention, the isocyanate compound having a bifunctional or higher functional isocyanate group is a bifunctional isocyanate monomer or a trifunctional monomer of adduct, burette, or isocyanurate type. It is a derivative | guide_body, The laminated body of Claim 1 characterized by the above-mentioned.

  The laminate of the present invention comprises at least three layers of a plastic substrate layer, an adhesive layer, and a sealant layer, and the adhesive layer is not affected by the strong penetrating contents, and an extremely thin and dense layer is formed. Because it is formed, it exhibits excellent laminate strength against plastic substrates, and various strongly permeable contents containing volatile substances such as acidic substances, alkaline substances, fragrances, surfactants, organic solvents, etc. Even if it is used as a packaging material that preserves, the laminate strength between the plastic substrate and the sealant layer does not decrease, and furthermore, heat aging for several days after lamination is unnecessary, and stable due to short-term room temperature aging It became possible to obtain a laminate having sufficient laminate strength.

  Hereinafter, an example of an embodiment of the present invention will be described in detail.

  As the plastic substrate constituting the laminate of the present invention, polyester film normal type, copolymer type, easy adhesion type, etc., nylon film normal type, easy adhesion type, etc., polypropylene film non-static type, static prevention Various types such as types can be used.

Moreover, an aliphatic polyester film and an aliphatic aromatic polyester film can also be used. 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- Uses copolymers of hydroxybutyrate, 3-hydroxyvalylate, caprolactone, copolymers of dicarboxylic acids such as succinic acid and adipic acid and diols such as ethylene glycol and 1,4-butanediol, or mixtures thereof Is possible. In addition, 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 with terephthalic acid, polybutylene adipate -Terephthalate, polytetramethylene adipate-terephthalate, etc. can also be used. Any type of film can be used as a substrate as long as a surface treatment such as corona treatment is performed on one of the surfaces and an adhesive layer can be stably formed thereon. Further, the thickness is not particularly limited.

  Moreover, the film which provided the vapor deposition thin film layer which consists of an inorganic oxide on the said plastic base material can also be used, and a vapor deposition thin film layer is from vapor deposition films, such as aluminum oxide, silicon oxide, magnesium oxide, a tin oxide, or those mixtures. That is, any material having a gas barrier property such as oxygen or water vapor may be used. Among these, aluminum oxide, silicon oxide, and magnesium oxide are particularly preferable because of their excellent oxygen barrier properties and water vapor barrier properties.

  When providing a vapor-deposited thin film layer made of an inorganic oxide on the plastic substrate, in order to improve the adhesion with the vapor-deposited thin film layer, as a pretreatment, corona treatment, low-pressure plasma treatment, atmospheric pressure plasma treatment, flame treatment, Surface treatment such as ion bombardment treatment may be performed, and surface treatment such as chemical treatment or solvent treatment may be performed. Moreover, it is possible to select the primer for vapor deposition according to various plastic base materials as needed. Furthermore, a gas barrier coating layer having an inorganic compound may be provided on the vapor-deposited thin film layer in order to impart a high level of gas barrier property comparable to that of a metal foil.

  The adhesive layer laminated on the plastic substrate has a thickness of 1 μm or less, 85% by weight or more of an isocyanate compound, and tri-n-propylamine or tri-n-butylamine 0.01 to 0.5% by weight. In addition to polyester polyol, polyether polyol, acrylic polyol, polyester polyurethane polyol, polyether polyurethane polyol and the like based on these can be used as the remaining component of about 15% by weight or less. The compound is not limited to these as long as it is not a compound that is too reactive with a group and gels immediately, and has good compatibility with an isocyanate compound.

  Examples of the isocyanate compound as the adhesive layer component include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate and hydrogen thereof. Specific examples include various diisocyanate monomers such as additives. 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.

  Tri-n-propylamine or tri-n-butylamine as the adhesive layer component is a tertiary amine and serves as a catalyst when a urea bond is formed by the reaction of the isocyanate group in the isocyanate compound with water. As a result, formation of urea bonds is promoted, heating aging for several days after laminating is unnecessary, and stable and sufficient laminating strength can be obtained by short-time room temperature aging.

In general, as the catalyst used for promoting the formation of the urea bond, a tin compound or a tertiary amine is used, but a tertiary amine is preferably used from the viewpoint of safety. Other tertiary amines include trimethylamine, triethylamine, N, N, N ′, N ′,-tetramethyl-1,3-butanediamine, 1,4-diazabicyclo [2,2,2] octane (tri Ethylenediamine), etc., but since the diluent solvent for the adhesive used to form the adhesive layer is usually ethyl acetate, it dissolves quickly and uniformly in ethyl acetate, is inexpensive, and is adhesive. The concentration of the catalyst inside must always be kept constant, and those having a higher boiling point, preferably 100 ° C. or higher, are optimal because they will not volatilize and cause a decrease in the concentration of the catalyst. For the above reasons, tri-n-propylamine or tri-n-butylamine was selected as the tertiary amine catalyst as the adhesive layer component of the present invention.

  The addition amount of tri-n-propylamine or tri-n-butylamine is 0.01 to 0.5% by weight, more preferably 0.01 to 0.1% by weight. If it is 0.5% by weight or more, it is not preferable because it is an excessive amount for promoting the formation of urea bonds, and an odor problem due to the amine odor of the resulting laminate may occur.

  Regarding the ratio of the isocyanate compound constituting the adhesive layer, for example, when a polyester polyol-rich adhesive layer is formed, such as a mixture of 90% by weight of polyester polyol and 10% by weight of isocyanate compound, the strongly penetrating contents have an adverse effect. The polyester polyol is swollen and the molecular weight is lowered, and the cohesive force of the adhesive layer is lowered, so that the laminate strength between the base material and the sealant layer is lowered with time. Therefore, by forming an isocyanate compound-rich adhesive layer, that is, the proportion of the isocyanate compound is 85% by weight or more, more preferably 90% by weight or more, an adhesive layer that is not affected by the strongly penetrating contents is provided. can get.

  As a method for forming this adhesive layer, a plastic substrate is composed of 85% by weight or more of an isocyanate compound and 0.01-0.5% by weight of tri-n-propylamine or tri-n-butylamine. What is necessary is just to apply and apply the coating liquid used as a dilution solvent. The solid content ratio of the coating liquid is 0.05 to 5% by weight, preferably 0.1 to 2% by weight. Further, the adhesive layer is preferably thin, and specifically, the adhesive layer may be provided so as to be a thin layer having a thickness of 1 μm or less when dried. When the thickness is 1 μm or more, it takes time for drying to evaporate the diluting solvent, and insufficient resistance to drying may make it difficult to develop resistance to the strongly permeable contents.

  As the sealant layer laminated on the adhesive layer, a layer made of a polyolefin resin such as a polyethylene resin or a polypropylene resin is generally used. Specifically, high density polyethylene, low density polyethylene, medium density polyethylene, ethylene resins such as ethylene-α olefin copolymer, homo-block / random polypropylene resins, propylene-α olefin copolymer, etc. Propylene resin, ethylene-α, β unsaturated carboxylic acid copolymer such as ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer, ethylene-methyl acrylate, ethylene-ethyl acrylate, ethylene-methacrylic acid Esterified products of ethylene-α, β unsaturated carboxylic acid copolymers such as methyl acrylate and ethylene-ethyl methacrylate, ethylene-α, β unsaturated carboxylic acid copolymer with carboxylic acid moiety cross-linked with sodium ion and zinc ion Ionic cross-linked products of polymers, ethylene-maleic anhydride graft copolymer and ethylene-acrylic Resin unit selected from acid anhydride-modified polyolefins typified by terpolymers such as ethyl-maleic anhydride, epoxy compound-modified polyolefins such as ethylene-glycidyl methacrylate copolymers, and ethylene-vinyl acetate copolymers Or a 2 or more types of blend thing etc. are mentioned concretely.

Also, aliphatic polyesters and aliphatic aromatic polyesters can be used. Specific examples of the constituent material include copolymers of dicarboxylic acids such as succinic acid and adipic acid and diols such as ethylene glycol and 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, polyester having an amide bond, aliphatic polyester such as polyester having a carbonate bond, or polyethylene terephthalate-succinate 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.

  Next, the manufacturing method of the laminated body of this invention is described. Solid content ratio in which ethyl acetate consisting of 85% by weight or more of isocyanate compound and 0.01-0.5% by weight of tri-n-propylamine or tri-n-butylamine is used as a diluent solvent on the plastic substrate. Is applied in the coating part of the extrusion laminating machine so that the thickness of the adhesive layer is 1 μm or less, preferably 0.05 to 5% by weight, preferably 0.1 to 2% by weight. An adhesive layer is provided, and after drying in an oven, a sealant layer extruded from a T-die made of, for example, polyethylene or the like is laminated to obtain a laminate having a structure of plastic substrate / adhesive layer / sealant layer.

According to the manufacturing method as described above, the initial strength between the plastic base material layer and the adhesive layer and between the adhesive layer and the sealant layer is good, and various strongly permeable contents containing volatile substances act. In addition, the laminate strength between the plastic base layer and the adhesive layer and between the adhesive layer and the sealant layer does not decrease. In addition, heat aging for several days after lamination is not required, and stable and stable lamination by short-time room temperature aging It became possible to produce a laminate having strength.
Hereinafter, embodiments of the present invention will be described with reference to examples.

<Example 1>
Using a polyethylene terephthalate film with a thickness of 12 μm with corona treatment on one side as a plastic substrate, the adduct type of tolylene diisocyanate using ethyl acetate as a diluting solvent on this corona treatment surface and the solid content Tri-n-propylamine with a ratio of 0.01% by weight is added, and a coating solution with a solid content of 2% by weight is applied to form an adhesive layer, dried in an oven, and then thickened as a sealant layer 40μm low density polyethylene was extruded by extrusion lamination method at a die temperature of 320 ° C and a processing speed of 80m / min to laminate the plastic substrate / adhesive layer and sealant layer, and then subjected to aging at 25 ° C for 12 hours. A laminate according to Example 1 was obtained. The thickness of the adhesive layer after drying was 0.25 μm.

<Example 2>
The adduct type of xylylene diisocyanate and polyester polyol are mixed as a coating liquid component of the adhesive layer so as to be 90:10 (weight ratio), and tri-n-propylamine 0.3 wt. A laminate according to Example 2 was obtained in the same manner as in Example 1 except that the coating solution added with% was used. The thickness of the adhesive layer after drying was 0.26 μm.

<Example 3>
Nylon film with a thickness of 15 μm with corona treatment on one side is used as the plastic substrate, and isocyanurate type of hexamethylene diisocyanate and polyether polyol as the coating liquid for the adhesive layer, 85:15 (weight ratio) This was carried out except that a coating liquid in which 0.5% by weight of tri-n-butylamine was added to 100% by weight of this mixture and an ethylene-methacrylic acid copolymer was used as a sealant layer. A laminate according to Example 3 was obtained in the same manner as in Example 1. The thickness of the adhesive layer after drying was 0.22 μm, and the temperature under the die at this time was 280 ° C.

<Comparative Example 1>
Implemented except that the coating liquid component of the adhesive layer was mixed with the adduct type of tolylene diisocyanate and the polyester polyol in a 75:25 (weight ratio) instead of the adduct type of tolylene diisocyanate. In the same manner as in Example 1, a laminate according to Comparative Example 1 was obtained. The thickness of the adhesive layer after drying was 0.25 μm.

<Comparative example 2>
As a coating liquid component of the adhesive layer, a coating liquid in which an adduct type of xylylene diisocyanate and a polyether polyol are mixed at 25:75 (weight ratio) instead of the adduct type of tolylene diisocyanate is used. A laminate according to Comparative Example 2 was obtained in the same manner as in Example 1 except that aging was performed for 5 days. The thickness of the adhesive layer after drying was 0.23 μm.

<Comparative Example 3>
A nylon film with a thickness of 15 μm with corona treatment on one side is used as a plastic substrate, and an isocyanurate type of hexamethylene diisocyanate is used instead of the adduct type of tolylene diisocyanate as the coating liquid component of the adhesive layer. A laminate according to Comparative Example 3 was obtained in the same manner as in Example 1 except that an ethylene-methacrylic acid copolymer was used as the sealant layer. The thickness of the adhesive layer after drying was 0.24 μm, and the temperature under the die at this time was 280 ° C.

  A pouch was produced by using the respective laminates of Examples 1, 2, 3 and Comparative Example 2 obtained by the above-described production method, and sufficient initial lamination strength was obtained, and the poultice was used as the contents. (Methyl salicylate and menthol are included as volatile strong osmotic substances) and bath agents (containing fragrance ingredients as volatile strong osmotic substances) are filled and sealed, and left in a constant temperature room at 40 ° C.

  After 3 months, these pouches are removed from the temperature-controlled room, and the laminate strength [N / 15mm] between the various plastic substrates and the sealant layer of each pouch is measured and compared with the initial laminate strength in the pouch before entering the temperature-controlled room. did. 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 1 summarizes the measurement results of the laminate strength before and after the constant temperature input.

表１からも明らかなように、実施例１〜３に係る積層体の各種プラスチック基材とシーラント層間における初期のラミネート強度は、シーラント切れを示すほど強固であった。また、揮発性物質を含む湿布薬や浴用剤を入れて４０℃で３ヶ月間保存したパウチにおいてもラミネート強度に変化はなく、初期のラミネート強度を十分に保っていた。

As is clear from Table 1, the initial laminate strength between the various plastic substrates and the sealant layers of the laminates according to Examples 1 to 3 was so strong that the sealant was broken. Further, even in the pouch stored with a poultice containing a volatile substance and a bath agent and stored at 40 ° C. for 3 months, the laminate strength did not change, and the initial laminate strength was sufficiently maintained.

  In contrast, the initial laminate strength between the plastic substrate and the sealant layer of the laminates according to Comparative Examples 1 and 3 was not sufficiently obtained.

In addition, the initial laminate strength between the plastic substrate and the sealant layer of the laminate according to Comparative Example 2 was strong enough to show a sealant breakage by performing sufficient heat aging at 50 ° C. for 5 days. In a pouch that has been stored for 3 months at 40 ° C with a poultice or bathing agent containing volatile substances, the laminate strength is significantly reduced, and the packaging material for the contents containing volatile substances such as poultices and bathing agents It turned out to be unsuitable for use.

Claims (2)

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 the adhesive layer has an isocyanate compound having a bifunctional or higher functional isocyanate group of 85% by weight or more; 0.01 to 0.5 wt% of tri -n- propylamine or tri -n- butylamine Tona is,
The initial laminating strength between the plastic substrate and the sealant layer is 4.6 N / 15 mm to 5 in a measurement condition in which aging is performed at 25 ° C. for 12 hours, and T-type peeling with a sample width of 15 mm and peeling speed is 300 mm / min .8N / 15mm der Rukoto laminate according to claim.   2. The isocyanate compound having a bifunctional or higher functional isocyanate group is a bifunctional isocyanate monomer or a derivative of a trifunctional monomer of any one of adduct, burette, and isocyanurate types. The laminated body of description.