JP2005001184A - Heat-sealable laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-sealable laminate having high blocking resistance even at a high temperature, capable of being bonded at a low temperature and showing high adhesiveness after bonding. <P>SOLUTION: The heat-sealable laminate is characterized in that a heat-sealable layer is provided on a support and a discontinuous blocking preventing layer is laminated thereon. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat seal laminate having good low temperature heat sealability and excellent block resistance.
[0002]
[Prior art]
The sheet member having a heat seal adhesive layer is used for various packaging materials, handicrafts, and recording materials, but blocking during conveyance in a wound state or a laminated state has been a problem. When selecting a heat seal adhesive layer, if importance is placed on blocking resistance at high temperatures, the adhesive strength with the adherend is weakened, or high heat energy is required for heat sealing. For example, when the heat-resistant temperature of the material is low, such as a heat-sealable material having a heat-sensitive recording layer or an ink-receiving layer, an adhesive layer having a low-temperature heat-seal property is necessary. However, if importance is attached to the adhesive strength at a low temperature, there is a problem that blocking tends to occur. As a method of avoiding blocking, a method of embossing the heat seal adhesive layer or a method of roughening the surface by adding a pigment is mainly employed. (For example, Patent Document 1)
[0003]
In addition, when transportation by ship or high temperature is unavoidable, measures such as inserting a separator with low adhesion between sheets are taken, but handling becomes worse and only excess waste is generated. In addition, an increase in transportation costs is inevitable. Therefore, a heat seal laminate having blocking resistance at high temperature and capable of bonding at low temperature has been desired.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-13836
[Problems to be solved by the invention]
An object of the present invention is to provide a heat seal laminate that has high blocking resistance even at high temperatures, can be bonded at a low temperature, and exhibits strong adhesion after bonding.
[0006]
[Means for Solving the Problems]
As a result of studying to solve these problems, the present inventors have provided a heat seal layer on a support, and laminated a discontinuous anti-blocking layer thereon. I found that the problem was solved.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, there is provided a heat seal laminate that has high blocking resistance even at high temperatures, can be bonded at a low temperature, and exhibits strong adhesion after bonding.
[0008]
The heat seal laminate of the present invention comprises a support, a heat seal layer, and an antiblocking layer. The discontinuity of the discontinuous anti-blocking layer according to the present invention means that there are defects or cracks in the surface, and the layer may be a mesh, stripe or island. Conversely, continuous means that there are no defects or cracks in the surface. The anti-blocking layer according to the present invention may be either continuous or discontinuous at normal temperature, but it must be discontinuous at the time of bonding. When the surface on which the heat seal layer of the support is provided is the adhesive surface, and the surface on which the heat seal layer is not provided is the surface, in the case where the heat seal laminate of the present invention is in a wound state or in a state where a plurality of layers are stacked However, since there is an anti-blocking layer between the surface and the heat seal layer, it is possible to prevent blocking without exhibiting adhesiveness and tackiness even at temperatures in the vehicle and in the ship that are higher than the normal ambient temperature. On the other hand, when bonding, heat and pressure are applied, and the softened adhesive component of the heat seal layer comes into contact with the adherend to develop an adhesive force. In addition, in the case of a continuous anti-blocking layer at normal temperature, cracking occurs due to heat and pressure, and the layer becomes discontinuous. Expresses power.
[0009]
The anti-blocking layer according to the present invention is a material capable of forming a thin film on the heat seal layer, and is not particularly limited as long as the material itself does not exhibit tackiness and adhesiveness at room temperature. The material of the blocking layer can be selected according to the type of the heat seal layer and the adhesion of the adherend. Preferably, a material with low chemical affinity with the heat seal layer is preferable. For example, examples of the inorganic compound include metal films such as gold, silver, copper, aluminum, and magnesium, and inorganic oxides such as silicon oxide, aluminum oxide, and magnesium oxide. In the case where the heat seal laminate is used in a transparent state or when it is preferable to have less coloring, an inorganic oxide is preferable. As the organic compound, any material that can form a thin film such as a phthalocyanine derivative or a fatty acid derivative can be used.
[0010]
The thickness of the anti-blocking layer can be arbitrarily set depending on the kind of the heat seal layer and the adherend. As a preferable thickness, the average of the film is 0.1 nm to 1000 nm or less, and more preferably 500 nm or less.
[0011]
Examples of the method for forming the anti-blocking layer include a vacuum deposition method, an ion plating method, a sputtering method, a coating method, a plasma polymerization method, and the like, but are not particularly limited to these methods. A vacuum vapor deposition method, a sputtering method, and an ion plating method are preferable in that a thin film can be stably and industrially produced.
[0012]
The heat seal layer according to the present invention can be selected depending on the material of the support and the adherend, but a material having a temperature required for adhesion of 160 ° C. or less is preferable. As specific constituent resins, polyester resins, urethane resins, modified olefin resins, epoxy resins, silicon resins, acrylic resins, nylon resins, styrene resins, and vinyl resins can be used alone or in combination.
[0013]
As a method for forming the heat seal layer, for example, there is a method of coating in the form of an organic solvent solution or an aqueous dispersion solution in addition to a method of coating without a solvent. The heat seal layer obtained by preparing a coating solution using the above resin and applying and drying at a temperature higher than the minimum film-forming temperature is dried in a normal state without stickiness even when touched with a finger. .
[0014]
The heat seal layer of the present invention further includes other additives such as a dispersant, a thickener, a fluidity improver, an antifoaming agent, an antifoaming agent, a release agent, a foaming agent, a penetrating agent, a coloring dye, Color pigments, fluorescent brighteners, UV absorbers, antioxidants, antiseptics, antibacterial agents, water resistance agents, wet paper strength enhancers, dry paper strength enhancers, antistatic agents, anti-aging agents, etc. You can also
[0015]
Examples of the method for applying the heat seal layer of the present invention include a gravure coater, a gravure offset coater, a bar coater, a roll coater, an air knife coater, a U comma coater, an AKKU coater, a smoothing coater, a micro gravure coater, a reverse roll coater, Any coating method can be used in consideration of the form and suitability of the resin constituting the adhesive layer, such as a 4- or 5-roll coater, blade coater, dip coater, drop curtain coater, slide coater, die coater, and melt extrusion die. Good.
[0016]
Examples of the support according to the present invention include paper, non-woven fabric, synthetic resin, synthetic paper, metal plate, metal stay, and glass. Synthetic resin materials include polycarbonate, epoxy resin, polyolefin resin such as polyethylene, polypropylene, TPX, polyester resin, polyamide resin, polyvinyl acetate, styrene vinyl acetate copolymer resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride Synthetic resin materials such as polystyrene, polyvinyl ether, polyvinyl ketone, polyether, polyvinyl alcohol resin, diene resin, and polyurethane resin can be used. These synthetic resin materials may be used as they are, or may be used by blending them. Alternatively, a pigment may be kneaded and used, for example, as a white plastic sheet. A composite sheet combining paper, various non-woven fabrics, woven fabric, synthetic resin film, synthetic resin laminated paper, synthetic paper, metal foil, glass, etc. can be arbitrarily used depending on the purpose, and further, transparent, translucent or Any of opaque may be sufficient. Moreover, it is not limited to these.
[0017]
When these layers are provided, there is no problem in performing surface treatment such as corona discharge for the purpose of improving adhesiveness.
[0018]
【Example】
Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples. In addition, the number of parts in an Example is a mass reference | standard.
[0019]
Example 1
A water-based polyester resin having a crow transition point of 0 ° C. and a softening point of 135 ° C. was applied as a heat seal adhesive layer on a PET film (25 μm) at a solid content of 10 g / m ² to form a heat seal layer. Next, using Hitachi E1030 ion sputtering, the distance between the target and the heat seal layer was set to 30 cm, the gold was coated for 5 seconds under the conditions of a vacuum degree of 6 Pa and a discharge current value of 15 mA, and the heat seal laminate of Example 1 was obtained. Produced.
[0020]
[Adhesion test]
A PET sheet (250 μm) was placed on the heat seal surface (5 cm square), and a pressure of 300 kgf was applied at a temperature of 135 ° C. for 15 minutes for adhesion. The bonded sheet was cooled to room temperature and attempted to be peeled off, but it was broken and had sufficient adhesive strength.
[0021]
[Anti-blocking test]
A PET film (5 cm square) was placed on the heat seal surface (5 cm square), and a 10 kg weight was placed thereon and heated for 3 days with a drier at 70 ° C., but the two sheets could be easily peeled off.
[0022]
Comparative Example 1
A heat seal laminate of Comparative Example 1 was prepared in the same manner as in Example 1 except that gold was not coated, and an adhesion test resistance and a blocking test were performed. As a result, in the adhesion test, sufficient adhesive strength was obtained as in Example 1. On the other hand, in the anti-blocking test, it tried to peel off, but it broke and could not be peeled off.
[0023]
【The invention's effect】
According to the present invention, it is possible to provide a heat seal laminate that has high blocking resistance even at high temperatures, can be bonded at a low temperature, and exhibits strong adhesion after bonding.

Claims (1)

A heat seal laminate comprising a heat seal layer provided on a support and a discontinuous anti-blocking layer laminated thereon.