JP2013001427A - Water-repellent packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-repellent packaging material which prevents an adhesive content such as a liquid or a semi-solid and gel material from adhering to or staying on the inner surface of the packaging materia, and which has excellent heat sealing property.SOLUTION: The water-repellent packaging material is prepared by sequentially stacking, on at least one surface of a base material, a seal layer including a fine particle with the surface covered with a heat-sealable resin and a silane coupling agent, and a water-repellent layer including a hydrophobic silicone resin. That is, by covering the surface of the fine particles with the silane coupling agent, a silane cross-linked polymer layer is formed between the heat sealable resin and the fine particles, and the strength and the adhesion of the fine particles are improved. As a result, adhesive strength between the seal layer and the base material and between the seal layer and the water-repellent layer are improved.

Description

  The present invention relates to a material for packaging foods, beverages, pharmaceuticals, chemicals, and the like, and particularly to a packaging material for contents having a viscous material such as a liquid, a semi-solid, or a gel substance.

  Conventionally, packaging materials corresponding to respective contents have been developed for many products such as foods, beverages, pharmaceuticals, and chemicals. In particular, as a packaging material for contents having a viscous material such as a liquid, semi-solid, or gel substance, a plastic material having excellent water resistance, oil resistance, gas barrier properties, light weight, flexibility, design properties, etc. is used. Is functioning to protect the contents required for

  In addition, as a packaging material for contents having viscous bodies such as liquids, semi-solids, gel substances, etc., for the purpose of providing higher functionality, a plastic laminate in which a plurality of various plastic substrates are laminated, paper, metal There have been proposed foils, composite laminates with inorganic materials, and composites obtained by applying a functional composition to a plastic substrate.

  As one of the high functions described above, for example, there is an attempt to prevent the content having a viscous material such as a liquid, a semi-solid, or a gel substance from adhering to the inner surface of the packaging material, that is, remaining inside the packaging body. Specifically, it is used for container materials such as yogurt, jelly, and syrup, retort food packaging materials such as porridge and soup, and film materials for storage containers such as chemical and pharmaceutical liquids, semi-solids, and gel substances. This is a method for solving the problem of substantial loss that cannot be removed due to the adhesion of contents and the contamination due to the adhesion of contents.

  With respect to these problems, for example, in Patent Document 1, hydrophobic oxide fine particles are attached to the outermost layer of the base material layer via a thermal adhesive layer, and most of the hydrophobic oxide fine particles are aggregates. Further, a packaging material having a porous layer having a three-dimensional network structure has been proposed.

  Further, in Patent Document 2, a heat-sealing lid material in which a heat-sealing layer and a content adhesion preventing layer are sequentially laminated on a base material, the content adhesion preventing layer being formed from wax and a filler dispersed in wax. In other words, it is a proposal that the filler is made of inorganic powder, organic powder, powder water-repellent resin, or the like.

  However, the proposal described in Patent Document 1 is a method of applying a coating liquid in which hydrophobic oxide fine particles are dispersed on an adhesive layer, and the strength of the interface between the adhesive layer and the coating liquid can be obtained. There is a problem that it is difficult to control the adhesion strength between physical particles. Further, the proposal described in Patent Document 2 has a problem that it is difficult to control the adhesion between the wax and the filler dispersed in the wax, that is, the cohesive force of the content adhesion preventing layer. Therefore, each proposal has a problem in achieving both adhesion strength with the base material and prevention of adhesion of contents.

Patent No. 4348401 JP 2009-73523 A

  The object of the present invention is that the content does not adhere to or remain on the inner surface of the packaging material with respect to the content having adhesive properties such as liquid, semi-solid and gel-like substances, and has excellent heat sealability. It is to provide a water repellent packaging material.

  In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention provides a sealing layer comprising fine particles coated with a silane coupling agent on at least one surface of a base material and a resin having heat sealing properties. And a water-repellent packaging material characterized in that a water-repellent layer containing a hydrophobic silicone resin is sequentially laminated. That is, by covering the surface of the fine particles with a silane coupling agent, a silane cross-linked polymer layer is formed between the resin having heat sealability and the fine particles, and the strength and adhesion of the fine particles are improved. The effect of improving the adhesion strength between the seal layer and the substrate and between the seal layer and the water-repellent layer is obtained.

  The invention according to claim 2 of the present invention is characterized in that the hydrophobic group of the hydrophobic silicone resin contained in the water repellent layer is arranged on the opposite side of the lamination interface with the seal layer. 1. The water repellent packaging material according to 1. That is, the hydrophobic group of the hydrophobic silicone resin contained in the water-repellent layer is arranged on the opposite side of the lamination interface with the seal layer, so that liquids, semi-solids and gel substances having hydrophilicity in particular The water repellency acts more efficiently on the contents, thereby bringing about the effect of preventing the contents from adhering.

  The invention according to claim 3 of the present invention is the water-repellent packaging material according to claim 1 or 2, wherein the fine particles are made of polyethylene wax having a number average molecular weight of 300 to 10,000. When the number average molecular weight of the fine particles made of polyethylene wax is in the range of 300 to 10,000, the melting point is relatively low and it is easy to fix to the substrate, so that the effect of improving water repellency can be obtained as unevenness of several μm order. .

  The invention according to claim 4 of the present invention is characterized in that the silane coupling agent comprises an alkoxysilane having at least one of a methacryl group, an amino group, a mercapto group and an epoxy group as a reactive functional group. The water repellent packaging material according to any one of Items 1 to 3. The reactive functional group reacts with the organic polymer, resulting in strong adhesion.

  The invention according to claim 5 of the present invention is the water-repellent packaging according to any one of claims 1 to 4, wherein the surface roughness of the seal layer is an arithmetic average roughness (Ra) of 200 or more. It is a material. When the surface roughness of the sealing layer is an arithmetic average roughness (Ra) of 200 or more, an effect of increasing the water repellency can be obtained by suppressing the contact area with the solid surface.

  According to the present invention, the content does not adhere to or remain on the inner surface of the packaging material with respect to the content having adhesive properties such as liquid, semi-solid and gel-like substances, and has excellent heat sealability. A water repellent packaging material can be provided.

It is a cross-sectional schematic diagram of one Embodiment of the water-repellent packaging material of this invention. It is a cross-sectional schematic diagram of the sealing layer which concerns on this invention.

  The present invention will be described below with reference to the drawings. FIG. 1: shows the cross-sectional schematic diagram of one Embodiment of the water-repellent packaging material of this invention. As shown in FIG. 1, in the present invention, a sealing layer 2 composed of a resin 4 having heat sealing properties and fine particles 5 whose surfaces are coated with a silane coupling agent 6 is formed on one side of a base material 1. A water repellent packaging material 10 comprising a water repellent layer 3 containing a hydrophobic silicone resin laminated thereon.

  As the base material 1 according to the present invention, a plastic film alone, a laminate of different plastic films, a composite laminate of a plastic film and paper, metal foil, or an inorganic material can be used.

  Moreover, as resin 4 which comprises the said sealing layer 2 which concerns on this invention, polyolefin resin, such as acrylic resin and polyethylene, can be used, and if it is resin which has heat-sealing property, it will not specifically limit.

  The fine particles 5 constituting the seal layer 2 according to the present invention are preferably polyethylene wax, more preferably polyethylene wax having a number average molecular weight of 300 to 10,000 and an average particle diameter of 1 to 5 μm. In particular, the average particle diameter of polyethylene wax has the effect of controlling the surface roughness of the sealing layer to an arithmetic average roughness (Ra) of 200 or more.

  Furthermore, as the silane coupling agent 6 constituting the seal layer 2 according to the present invention, a silane coupling agent based on an alkoxysilane structure can be used, and in particular as its reactive functional group, a methacryl group, an amino group, A silane coupling agent having a mercapto group and an epoxy group is preferred.

  The method for preparing the sealing layer composition is not particularly limited as long as the silane coupling agent can uniformly coat the fine particles, and general dispersion and mixing methods can be used.

  As the water-repellent layer 3 according to the present invention, a composition containing a hydrophobic silicone resin is preferable, and the kind and blending ratio of the hydrophobic silicone resin are not particularly limited.

  A method for forming the seal layer 2 and the water repellent layer 3 according to the present invention, that is, a method for applying each liquid composition is not particularly limited, and a general gravure coating method, a roll coating method, or the like can be used.

  Hereinafter, the present invention will be described specifically by way of examples.

<Example 1>
A base material obtained by laminating a polyethylene terephthalate (PET) film having a thickness of 12 μm and an aluminum foil having a thickness of 7 μm by a dry laminating method through an adhesive (manufactured by DIC, trade name “LX-500 / KW-75”). the aluminum surface, 10 g / m ² was applied by a gravure coating method a sealing layer composition having the following composition to form a sealing layer was dried at the conditions of 80 ° C. × 30 seconds.
<Sealing layer composition>
Acrylic resin 4 parts by mass Ethanol-dispersed polyethylene wax 5 parts by mass (trade name “MW-150” manufactured by Koyo Chemical Co., Ltd.)
(Number average molecular weight 800, solid content 10% by weight)
Silane coupling agent (momentive A-174) 1 part by mass

Next, 10 g / m ² of a water repellent layer composition having the following composition is applied onto the sealing layer by a gravure coating method, and dried at 100 ° C. for 60 seconds to form a water repellent layer, thereby forming a water repellent packaging material. Was made.

<Water repellent layer composition>
Silicone resin (momentive XC96-B0446) 100 parts by mass Solvent (MEK) 100 parts by mass Initiator 1 part by mass (Organic tin catalyst: Nitto Kasei Co., Ltd., trade name “Neostan U-820”)

<Example 2>
A water-repellent packaging material was produced in the same manner as in Example 1 except that the polyethylene wax in the seal composition used a number average molecular weight of 2000.

<Comparative Example 1>
A water-repellent packaging material was prepared in the same manner as in Example 1 except that, as a sealing composition, an acrylic heat sealant was used instead of polyethylene wax and a silane coupling agent, and 10 g / m ^{2 was} applied by gravure coating. Produced.

<Evaluation items and methods>
Using the water-repellent packaging material produced in Examples 1 and 2 and Comparative Example 1, the sealing strength, contact angle, and falling angle after heat sealing were measured. The results are shown in Table 1 below.
-Seal strength-The water-repellent layer side of the water-repellent packaging material was overlapped, and heat sealed using an impulse sealer at 150 ° C for 5 seconds. Then, it cut | judged to 15 mm width and measured the intensity | strength at the time of 90 degree | times peeling with a tensile tester.
-Contact angle-Water and yogurt (Morinaga aloe yogurt) were dropped on the water-repellent layer of the water-repellent packaging material, and the contact angle was measured.
Falling angle-Dropped by the above method, the water-repellent packaging material was tilted with the dropping liquid placed thereon, and the angle at which the dropping liquid rolled down was measured as the falling angle.

<Comparison result>
The products of the present invention obtained in Examples 1 and 2 have high contact angles with water of 150 ° and 145 °, respectively, and good water repellency was obtained. In addition, a high contact angle of 120 ° and 115 ° and a falling angle of <10 ° were obtained for highly viscous yogurt, respectively. On the other hand, the comparative product obtained in Comparative Example 1 had a small contact angle with respect to both water and yogurt, and adhesion of yogurt was observed at the falling angle. From the above, the product of the present invention has excellent water repellency and shows very good results with no decrease in seal strength.

DESCRIPTION OF SYMBOLS 1 Base material 2 Seal layer 3 Water repellent layer 4 Resin 5 Fine particle 6 Silane coupling agent 10 Water repellent packaging material

Claims (5)

  A seal layer composed of fine particles coated with a silane coupling agent and a heat-sealing resin and a water-repellent layer containing a hydrophobic silicone resin are sequentially laminated on at least one surface of the substrate. A water-repellent packaging material.   The water-repellent packaging material according to claim 1, wherein the hydrophobic groups of the hydrophobic silicone resin contained in the water-repellent layer are arranged on the opposite side of the laminated interface with the seal layer.   The water-repellent packaging material according to claim 1 or 2, wherein the fine particles are made of polyethylene wax having a number average molecular weight of 300 to 10,000.   The repellent agent according to any one of claims 1 to 3, wherein the silane coupling agent comprises an alkoxysilane having at least one of a methacryl group, an amino group, a mercapto group, and an epoxy group as a reactive functional group. Aqueous packaging material.   The water-repellent packaging material according to any one of claims 1 to 4, wherein the surface roughness of the seal layer is an arithmetic average roughness (Ra) of 200 or more.

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