JP4852874B2 - Manufacturing method of laminate - Google Patents

Description

  The present invention relates to a laminate in which at least an adhesive layer and a sealant layer are provided in this order on a substrate made of polyester, nylon, or polypropylene, and has excellent laminate strength with respect to those substrates. In addition, the present invention relates to a laminate in which the laminate strength between the base material and the sealant layer does not decrease even when volatile components or various strongly permeable contents containing volatile components act.

  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 lamination of the polyester layer and the sealant layer of this laminate is usually performed by applying an anchor coating agent such as a two-component curable polyurethane to the polyester layer made of a polyester film and then extruding the sealant layer. It was. 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 organic solvent, etc., and when these contents are packaged, an adhesive that constitutes an adhesive layer In some cases, the laminate strength may be lowered or peeling may occur in the laminate.

  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 laminate having the structure as described above or the laminate obtained using the anchor coating agent is used. Is used as a packaging material, and when these contents are packaged, the laminate strength between the polyester layer and the sealant layer made of polyester film decreases with time due to the strong penetration of volatile substances, resulting in delamination. There was a problem of causing.
Japanese Patent Laid-Open No. 10-130615

The present invention has been made in order to solve the above-mentioned conventional problems, and the problem is that at least an adhesive layer and a sealant layer are formed on a base material made of polyester, nylon, or polypropylene. Laminated bodies provided in order have excellent laminate strength with respect to those base materials, and those base materials even when various strongly permeable contents including volatile components and volatile components act Another object is to provide a method for producing a laminate in which the laminate strength between the sealant layers does not decrease.

In order to solve the above-described problems, the invention according to claim 1 is characterized in that the one side of the base material made of polyester, nylon or polypropylene is subjected to a corona treatment in-line, and the one subjected to the corona treatment. An adhesive layer made of a difunctional isocyanate monomer or an isocyanate compound which is a derivative of a trifunctional monomer of adduct, burette, or isocyanurate type is formed on the surface of The sealant layer is extruded at a temperature of 330 ° C. or lower, and the surface of the sealant layer in contact with the adhesive layer is subjected to ozone treatment, and then the base material and the sealant layer are laminated via the adhesive layer. It is the manufacturing method of the laminated body to perform.

Furthermore, the invention described in claim 2 is the laminate according to claim 1 , wherein the thickness of the adhesive layer made of the isocyanate compound is 1 μm or less.

Furthermore, the invention described in claim 3 is the laminate according to claim 1 or 2 , wherein the sealant layer is made of a polyethylene resin or a polypropylene resin.

  The laminate of the present invention is composed of at least three layers of a base material made of polyester, nylon or polypropylene, an adhesive layer, and a sealant layer, and the adhesive layer is made of a thin layer of an isocyanate compound. In contrast, the laminate strength is excellent. 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 base material and the sealant layer does not decrease, and delamination does not occur.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic cross-sectional structure of a laminate according to the present invention.

  The laminate 1 is formed by laminating an adhesive layer 3 and a sealant layer 4 in this order on a substrate 2.

  The base material 2 constituting the laminate of the present invention is made of polyester, nylon or polypropylene. More specifically, it is made of any one of a polyester film, a nylon film, and a polypropylene film.

  There are various types of polyester film such as normal type, copolymerized type, and easy-adhesion type, nylon film normal type and easy-adhesion type, and polypropylene film with non-static type and static-proof type. However, any type of film can be used as a substrate as long as surface treatment such as corona treatment is performed on one surface of the surface and an adhesive layer can be stably formed thereon. Further, the thickness is not particularly limited.

  On the other hand, the adhesive layer 3 is a layer made of an isocyanate compound. Examples of the isocyanate compound constituting the adhesive layer 3 include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, and the like. Specific examples include various diisocyanate monomers such as hydrogenated products. 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.

  The adhesive layer 3 is coated on the base material 2 with a coating solution containing, for example, the above-described isocyanate compound in a solid content ratio of 0.05 to 5 wt%, preferably 0.1 to 2 wt%. It only has to be installed. The adhesive layer 3 is preferably a thin layer. Specifically, the adhesive layer 3 may be provided so as to be a thin layer having a thickness of 1 μm or less when dried.

  On the other hand, the sealant layer 4 provided on the adhesive layer 3 is a layer made of polyethylene resin, polypropylene resin, or the like. Specifically, ethylene resins such as high density polyethylene, low density polyethylene, medium density polyethylene, 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 Ethylene-α, β-unsaturated carboxylic acid copolymers such as methyl methacrylate 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 copolymers and polymers Selected from acid anhydride-modified polyolefins typified by terpolymers such as tylene-ethyl acrylate-maleic anhydride, epoxy compound-modified polyolefins such as ethylene-glycidyl methacrylate copolymers, and ethylene-vinyl acetate copolymers It is provided by a single resin or a blend of two or more. You may add various additives (Antioxidant, a tackifier, a filler, various fillers, etc.) to these structural materials as needed.

  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.

  Moreover, the laminated body of such a structure can be produced as follows, for example.

  That is, as one of the production methods, the solid content ratio of the isocyanate compound is 0.05 to 5 wt%, preferably 0.1 to 2 wt% on the surface of the base material that has been subjected to surface treatment such as corona treatment. After the coating liquid prepared as described above is applied at the coating part of the extrusion laminate to provide an adhesive layer, a sealant made of, for example, polyethylene or the like having a die lower temperature of 320 ° C. extruded from the T-die on the adhesive layer. An example is a method of laminating layers to obtain a laminate composed of three layers of substrate / adhesive layer / sealant layer.

  As another production method, immediately after performing in-line corona treatment on one surface of the above-described base material, a coating liquid containing an isocyanate compound is applied at the anchor coating agent coating portion of the coating apparatus. While forming the adhesive layer, ozone treatment is appropriately applied to the surface of the sealant layer made of, for example, polyethylene, which is extruded from the T die and having a temperature of 320 ° C., for example, polyethylene, and then the base material is passed through the adhesive layer. And laminating the sealant layer, the interlayer laminate strength is further improved, and a method of obtaining a laminate having excellent resistance to various strongly permeable contents can be mentioned.

In this case, the temperature under the die is preferably 250 to 330 ° C. Below 250 ° C, even if the ozone treatment is performed, the interlayer laminate strength becomes insufficient due to insufficient oxidation of the extruded resin. Become. Moreover, as an ozone treatment condition at this time, 5-20 mg / m < ² > is preferable. If it is less than 5 mg / m ² , the interlayer laminate strength is insufficient due to insufficient oxidation of the extruded resin, and if it exceeds 20 mg / m ² , the cohesive force of the extruded resin is reduced due to excessive oxidation, resulting in insufficient interlayer laminate strength. . By appropriately combining the extrusion temperature and the ozone treatment conditions, it is possible to obtain a laminate excellent in resistance to various strongly permeable contents with further improved interlayer laminate strength.

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

  A normal type biaxially stretched polyester film having a thickness of 12 μm and subjected to corona treatment on one surface as a base material, and a coating prepared by adding isophorone diisocyanate monomer to the corona treatment surface so that the solid content ratio is 2 wt%. While forming the adhesive layer by applying the working liquid, a 40 μm-thick low-density polyethylene is extruded by extrusion lamination at a temperature under the die of 320 ° C. and a processing speed of 80 m / min, and a sealant layer (thickness 40 μm) is formed on the adhesive layer. As a result, a laminate according to Example 1 was obtained. The thickness of the adhesive layer after drying was 1 μm.

  A laminate according to Example 2 was obtained in the same manner as in Example 1 except that an adduct type of tolylene diisocyanate was used as the adhesive layer and an ethylene-methacrylic acid copolymer was used as the constituent material of the sealant layer. At this time, the temperature under the die was 305 ° C.

  Use a copolymer type biaxially stretched polyester film with a thickness of 12 μm with corona treatment on one side as the base material, and use a hexamethylene diisocyanate burette type material as the constituent material of the adhesive layer. A laminate according to Example 3 was obtained in the same manner as in Example 1 except that random polypropylene was used as the constituent material of the layer. The temperature under the die at this time was 280 ° C.

A normal type biaxially stretched polyester film having a thickness of 12 μm and subjected to corona treatment on one surface as a substrate is used, and the solid content ratio becomes 2 wt% immediately after inline corona treatment on the corona treatment surface. An adduct type adhesive layer of tolylene diisocyanate prepared as described above was formed, while ozone treatment was applied to the surface contacting the adhesive layer of a low-density polyethylene film having a temperature below the die of 320 ° C extruded from the T die and having a thickness of 40 μm The laminate according to Example 4 was obtained by laminating at a processing speed of 80 m / min on the adhesive layer on the base material formed in the above step. The ozone conditions at this time were a concentration of 20 g / Nm ³ and a flow rate of 1.5 Nm ³ / (11 mg / m ² ).

  A laminate according to Example 5 was obtained in the same manner as in Example 1 except that a normal type biaxially stretched nylon film having a thickness of 15 μm and subjected to corona treatment on one surface was used as a substrate.

  A normal type biaxially stretched nylon film with a thickness of 15 μm with corona treatment on one side is used as the base material, and an adduct type of tolylene diisocyanate is used as the constituent material of the adhesive layer. A laminate according to Example 6 was obtained in the same manner as in Example 1 except that an ethylene-methacrylic acid copolymer was used as a constituent material. At this time, the temperature under the die was 305 ° C.

  Example 1 except that a non-static type biaxially stretched polypropylene film having a thickness of 20 μm and subjected to corona treatment on one surface was used as a base material, and an adduct type of tolylene diisocyanate was used as a constituent material of an adhesive layer. The laminated body which concerns on Example 7 was obtained by the method similar to.

  Uses a static-proof type biaxially stretched polypropylene film with a thickness of 20 μm with corona treatment on one side as the base material, uses a hexamethylene diisocyanate burette type as the constituent material of the adhesive layer, and further sealant A laminate according to Example 8 was obtained in the same manner as in Example 1 except that random polypropylene was used as the constituent material of the layer. The temperature under the die at this time was 280 ° C.

  A normal type biaxially stretched polyester film having a thickness of 12 μm and subjected to corona treatment on one surface is used as a base material, and a two-part curable polyurethane adhesive is 2 wt% on the corona-treated surface. The low-density polyethylene having a thickness of 40 μm was extruded by extrusion lamination at a temperature under the die of 320 ° C. and a processing speed of 80 m / min while applying the coating solution prepared as described above to form the adhesive layer. A laminate according to Example 9 for comparison was obtained by providing a sealant layer by laminating on the layer.

  Example 9 except that a normal type biaxially stretched nylon film having a thickness of 15 μm and subjected to corona treatment on one surface was used as a base material, and an ethylene-methacrylic acid copolymer was used as a constituent material of the sealant layer. By the same method, the laminated body which concerns on Example 10 for a comparison was obtained. At this time, the temperature under the die was 305 ° C.

  The same method as in Example 9 except that a non-static type biaxially stretched polypropylene film having a thickness of 20 μm and subjected to corona treatment on one surface was used as a substrate, and random polypropylene was used as a constituent material of the sealant layer. Thus, a laminate according to Example 11 for comparison was obtained. The temperature under the die at this time was 280 ° C.

  A pouch is prepared using each of the laminates of Examples 1 to 11 obtained as described above, and a poultice (containing methyl salicylate and menthol as a volatile strong permeable substance) as a content and for bath Each was filled with an agent (containing a fragrance component as a volatile strong penetrating substance), sealed, and left in a constant temperature room at 40 ° C.

  After the elapse of 3 months, these pouches were taken out from the temperature-controlled room, the laminate strength [N / 15 mm] between the various base materials and the sealant layer of each pouch was measured, and compared with the laminate strength in the pouch before entering the temperature-controlled room. 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１〜８に係る積層体を使用して作製されたパウチの各種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、実施例４の積層体においては、初期ラミネート強度で樹脂切れを示し、上記内容物を保存した後も樹脂切れを示すほど強固なラミネート強度が得られている。

As is clear from Table 1, the laminate strength between the various base materials and the sealant layers of the pouches produced using the laminates according to Examples 1 to 8 includes poultices and bathing agents containing volatile substances. Even when stored at 40 ° C. for 3 months, the initial laminate strength is sufficiently maintained. Moreover, in the laminated body of Example 4, the lamination | stacking intensity | strength was so strong that it showed resin running out by the initial lamination strength, and showed the resin running out after the said content was preserve | saved.

On the other hand, Examples 9 to 1 using a two-component curable polyurethane adhesive as the adhesive layer
Some pouches made using the laminate of 1 have a laminate strength that is so strong that the initial laminate strength shows that the resin has run out. However, a pouch containing a volatile substance or a bath agent is added. After being stored at 40 ° C for 3 months, the laminate strength has dropped significantly to 1.5 [N / 15mm] or less, and the packaging materials for contents containing volatile substances such as poultices and bath preparations It turned out to be unsuitable for use.

It is explanatory drawing which shows the schematic structure of the laminated body which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Base material 3 ... Adhesive layer 4 ... Sealant layer

Claims (3)

One side of a substrate made of polyester, nylon or polypropylene is subjected to in-line corona treatment, and the one side subjected to corona treatment is difunctional isocyanate monomer or adduct, burette, isocyanurate type While forming an adhesive layer made of an isocyanate compound that is a derivative of the trifunctional monomer, the sealant layer is extruded from a T die at a temperature below the die of 250 to 330 ° C. and is in contact with the adhesive layer of the sealant layer A method for producing a laminate , wherein the surface is subjected to ozone treatment, and then the base material and the sealant layer are laminated via the adhesive layer . The method for manufacturing a laminate according to claim 1, wherein the thickness of the adhesive layer formed from the isocyanate compound is 1μm or less. The method for producing a laminate according to claim 1 or 2 wherein the sealant layer, characterized in that a polyethylene resin or polypropylene resin.

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