Stock material or miscellaneous articles – Composite – Of addition polymer from unsaturated monomers
Reexamination Certificate
2001-02-21
2002-10-15
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of addition polymer from unsaturated monomers
C428S218000, C428S515000, C428S520000
Reexamination Certificate
active
06465109
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to laminated film composites suitable for use as a material would spirally in layers for packaging (hereinafter referred to as “spiral packaging”) for glass products and metal products.
The present invention relates to laminated film composites suitable for spiral packaging to prevent products from dust adhesion and damage when used for packaging various products such as coils and plates made of glass or metals.
Film laminates for packaging according to the present invention exhibit excellent adhesiveness between film surfaces owing to the self-adhesiveness of the front side and reverse side of the resin films. This prevents dust and rainwater from entering packages of assembly packaging of small products or spiral packaging of large products, so that the products can be well protected from getting dirty and rusting.
2. Description of the Related Art
Conventionally, packaging films made of thermoplastic resins are generally used for packaging ornaments, such as coils and plates made of glass or metals, metal products, or the like to prevent them from rusting or getting dusty. For example, films for preventing metal products from rusting are made by adding a volatile (or gasifiable) rust preventive to a thermoplastic resin and molding into a film using hot-melt extrusion molding (Japanese Patent No. S47-4295; Japanese Patent No. S53-2449). Today, these corrosion-inhibiting films are widely used in various areas because they are transparent and can easily be sealed by heat, which is their advantage over rustproof paper products. However, the high temperature used for the melt molding of the films, as well as the heat generated from the shearing of the resins per se increases the temperature of the resins, resulting in a loss of the volatile rust preventive. Even if a large amount of the volatile rust preventive be incorporated, very little of it be remained in the molded films. Thus, adequate rust prevention could not be maintained for prolonged periods.
Furthermore, resin films for preventing adhesion of dust or the like cannot be directly sealed because they have no self-adhesiveness. Therefore, in case of general bag packaging, the opening part has to be sealed with a separate tape made of adhesive materials, or outside air is obstructed by sealing the film at necessary places using a heat-sealing machine in order to prevent entry of dust and water. Either case is troublesome and complicated.
Nevertheless, thermoplastic resin films made of general-purpose resins such as low density polyethylene, high density polyethylene, polypropylene, and soft polyvinyl chloride resins are used for general packaging because of their easy availability and an economical advantage, i.e., low cost.
However, an adhesive is applied to the sealing site of the films upon packaging because the films per se do not have enough self-adhesiveness (Japanese Patent Laid Open, No. S61-21174).
In applying an adhesive to films for packaging, the adhesive has to be diluted with an organic solvent to apply it to the surface of the film base material and then dried. This pollutes the working environment due to dispersion of volatilized organic solvent contained in the adhesive and uneconomically increases the number of steps.
Furthermore, attempts were made to use ethylene vinylacetate copolymer resin films for packaging of metal products in place of the abovementioned general-purpose resins. In particular, a stretchable film using an ethylene vinylacetate copolymer resin was developed, in which self-adhesiveness was improved by increasing the content of vinyl acetate (Japanese Patent Laid Open, No. S60-155210). However, this film was not satisfactory, since rust was induced on metal products contacting the packaging film possibly because the resin per se has an intramolecular acetic acid group, or in case of non metal products, dust heavily adhered to the products. Moreover, the raw material, vinyl acetate, had a problematic odor.
SUMMARY OF THE INVENTION
Considering the abovementioned state, an object of the present invention is to develop a film suitable for packaging various kinds of products, wherein said film causes no environmental pollution from the use of organic solvents or the like, enables easy packaging, has strong self-adhesiveness, in particular on superposing sites, does not contaminate the working environment, and is highly economical.
A packaging film developed in the present invention is a laminated composite of resin films, each having a specific composition exhibiting mutual adhesiveness. This film is highly self-adhesive having an adhering property between the front side and reverse side of the film facing each other so as to prevent dust or water from entering the package, thus making it possible to provide products that will not lose their commercial value after prolonged storage. A packaging film laminate of the present invention can further exhibit a sealing effect particularly by spirally packaging products. Furthermore, a self-adhering effect can be exhibited, along with a rust preventing property, and a fragrance property by additionally placing a resin film containing a volatile component between the abovementioned layers as an intermediate layer.
The basic constitution of the present invention is a packaging film laminate comprising a laminated film in which a resin film layer obtained by mixing a specified amount of an adhesiveness-rendering resin having a specified range of resin density with an olefin resin base material having a similarly specified range of resin density is laminated with a resin film layer obtained by blending a specified amount of an adhesiveness-rendering resin having a specified range of resin density and a specified amount of a plasticizing oil with a linear polyethylene resin base material having a specified range of resin density.
Namely, the present invention comprises a laminated film composite suitable for spiral packaging, which comprises at least two layers containing (A) one layer comprising a resin composition containing at least one kind of adhesiveness-rendering resin having a resin density of more than 0.950 g/cm
3
selected from rosin resins, terpene resins or petroleum resins at a concentration of 0.002 to 12.0% by weight in a polyolefin resin having a resin density of more than 0.910 g/cm
3
(layer A), and (B) another layer comprising a resin composition containing at least one kind of resin selected from the abovementioned adhesiveness-rendering resins at a concentration of 0.05 to 25.0% by weight and at least one kind of plasticizing oil selected from mineral oils, polybutene, polyisobutylene, liquid polyacrylates and lanolin at a concentration of 0.01 to 8.0% by weight in a linear low density polyethylene resin having a resin density of 0.860 to 0.920 g/cm
3
(layer B).
Furthermore, the present invention also comprises a laminated film composite suitable for spiral packaging, which comprises at least two layers containing (A) one layer comprising a resin composition containing at least one kind of adhesiveness-rendering resin having a resin density of more than 0.950 g/cm
3
selected from rosin resins, terpene resins or petroleum resins at a concentration of 0.05 to 25.0% by weight and at least one kind of plasticizing oil selected from mineral oils, polybutene, polyisobutylene, liquid polyacrylates and lanolin at a concentration of 0.01 to 8.0% by weight in a polyolefin resin having a resin density of more than 0.910 g/cm
3
(layer A), and (B) another layer comprising a resin composition containing at least one kind of resin selected from the abovementioned adhesiveness-rendering resins at a concentration of 0.002 to 12.0% by weight in a linear low density polyethylene resin having a resin density of 0.860 to 0.920 g/cm
3
(layer B).
Furthermore, the present invention also comprises a laminated film composite suitable for spiral packaging comprising at least three layers further containing (C) one layer comprising a composition containing at least one k
Aicello Chemical Co., Ltd.
Knobbe, Martens Olson, and Bear, LLP.
Nakarani D. S.
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