Toyo Seikan Kaisha, Ltd.

Japan Crown Cork Co Ltd.

Go Kunimoto

Fumio Mori

Ken Takenouchi

Isao Ichinose

Noboru Suzuki

Mao Furusawa

A peelable adhesive structure is disclosed which comprises a plurality of parts at least one of which is made of metal, adhering together by means of a coating, characterized in that said coating has a peelable surface formed between a first layer of a denatured hydrocarbon resin or denatured hydrocarbon resin composition having an acid value of from 0.1 to 20 and a second layer containing an epoxy resin.

Peelable adhesive structure

A closure cap having a liner adhered to a cap shell by a plurality of coating layers. Prize markings are printed on one of the coating layers and are positioned between the coating layers. The peel resistance in the interface between the coating layers is less than that between the topmost coating layer and the liner to assure that the prize markings will be transferred to the liner when the liner is peeled from the cap shell. The liner includes a starting portion which adheres to the topmost coating layer only slightly to facilitate easy removal of the liner from the cap shell.

Closure cap having prize markings and peelable liner

A method of manufacturing peelable adhesive structures. It comprises preparing a first paint solution containing vinyl resin and a stably emulsified hydrocarbon or natural resin having softening point less than 180.degree. C. and concentration between 50 and 200 parts by weight per 100 parts of vinyl resin dispersed in a continuous phase of the vinyl resin. The first paint solution is applied onto a metal base material (1) to form a first coating layer (2). A second coating layer (3) is formed by applying a second paint solution containing epoxy resin and polyethylene oxide at a concentration of between 0.5 and 90 weight percent of epoxy resin over the first coating layer. The first and second coating layers have thicknesses ranging from about 0.5 to 100 mg/m.sup.2. A layer of olefin resin (4) is joined to the second coating layer. The method is further characterized in that at least one of the coating layers comprises a peeling imparter at a concentration of between 50 and 200 parts by weight per 100 parts by weight of resin, and a substantially linear saturated polyester wetting improver at a concentration of between about 2 and 50 parts by weight per 100 parts by weight of resin and having a molecular weight of between about 5,000 and about 50,000. The resulting peelable adhesive structure has a peeling strength between about 0.05 and 5 kg/cm between the first (2) and the second (3) coating layers.

Method to improve wetting of peelable adhesive structures

A container cap having a coated metal shell. A peelable adhesive layer joins a liner to the shell. The peelable adhesive layer comprises a local coating resin layer having a diameter less than that of the metal shell and a layer of an epoxy resin.

Container cap having a peelable liner

A peelable adhesive structure comprises a plurality of articles, including at least one metal article, bonded together through a composite coating layer. The composite coating layer comprises adjacent first and second coating layers, the first coating layer containing vinyl resin, and the second coating layer containing epoxy resin. At least one of the coating layers comprises:

Peelable adhesive structure and method for its manufacture

When a polyolefin layer is bonded to a metal substrate through a primer layer, if a polar group-containing ethylenically unsaturated monomer-modified olefin resin (A) having a specific polar group concentration and a specific degree of crystallinity and a coating film-forming base resin (B) are incorporated at a specific ratio into a specific mixed solvent to form a paint and the primer layer is formed by using this paint, there is obtained a novel multi-layer distribution structure comprising the base resin distributed predominantly in the portion of the primer layer contiguous to the surface of the metal substrate and the modified olefin resin distributed predominantly in the portion of the primer layer contiguous to the polyolefin layer and having a concentration gradient of the two components (A) and (B) in the thickness direction. By virtue of the presence of this primer layer, the bonding strength between the metal substrate and the polyolefin and the corrosion resistance of the metal substrate as well as the processability of the polyolefin-metal bonded structure are substantially improved.

Polyolefin-metal bonded structures and process for preparing same

A peelable bonded structure comprising a metal substrate and a polyolefin layer bonded to the substrate through a primer layer, wherein the primer layer is a composition comprising (A) a modified olefin resin having a carbonyl group concentration of 0.01 to 200 milliequivalents per 100 g of the olefin resin and (B) a coating film-forming base resin at an (A)/(B) weight ratio of from 0.1/99.8 to 70/30. The primer layer has in at least one first planar region thereof a multi-layer distribution structure having a resin concentration gradient in the thickness direction such that the modified olefin resin (A) is distributed predominantly in the portion of the primer layer contiguous to the polyolefin layer and the base resin (B) is distributed predominantly in the portion of the primer layer contiguous to metal substrate, and in at least one second planar region the modified olefin resin (A) is distributed in the portion of the primer layer contiguous to the polyolefin layer at a lower distribution ratio.

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Fujisawa, Japan

Go Kunimoto