Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-12-17
2004-08-24
Jackson, Monique R. (Department: 1773)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S184000, C156S191000, C428S457000, C428S461000, C428S513000
Reexamination Certificate
active
06780269
ABSTRACT:
DESCRIPTION
Method of manufacturing laminate for packaging material and laminate for packaging material.
1. Technical Field
This invention relates to a method of manufacturing of a laminate for packaging material, and its laminate. In detail, this invention relates to the method of manufacturing the laminate for packaging material which has an excellent barrier suitable for packaging of liquid food etc. at high speed, and its laminate.
2. Background Art
Conventionally, the laminate obtained from the laminating to the core paper of material, such as plastics, such as polyethylene (for example, low density polyethylene by the high-pressure method (LDPE) etc.), polypropylene, polyester, and polyvinyl chloride, metal foil, and a metal vapor deposited film, is used for the packaging material of liquid food. Such material is used in order to reveal the character of material each, to reinforce from the weak point of paper and to give a new function to packaging material.
Aluminum foil is widely used for the metal foil which is one of the material. The metallic foil gives water-resistant, damp-proofing, a gas barrier, a light barrier, etc. to the packaging material, and when using for the outside of packaging material, it has the advantage of making appearance of packaging into a metal tone and giving a high-class feeling.
The metal vapor deposited film is used as alternative of metal foil. The metal vapor deposited film used for the material of packaging material is manufactured mainly by the vacuum vapor deposit of aluminum. Since the vacuum deposition process usually evaporates metal at about 1300-degree C. of high temperature, a heat-resisting property and dimensional stability are required of the film used. Therefore, it is necessary to use the films generally improved by heat-resistant improvement processing of stretching of raw material plastics with high melting point or high glass transition temperature.
From the above-mentioned reason, the aluminium vacuum deposition film is used for the mono-axis or bi-axis oriented (stretched) film of a high density polyethylene, polypropylene, and a polyethylene terephthalate, in fact. However, from the cross-linking by stretching, since the film surface is high-crystallized, an adhesive property drops. Therefore, it is necessary to use the vapor deposited film which has a straight chain-like low density polyethylene film with affinity with a stretching film etc. for a vapor deposited film.
A stretching film is easily shrunk with the heat of a next laminating step. Especially mono-axis stretching high-density polyethylene has the defect that the tear strength of length or a transverse direction is very weak, from the properties. From the above-mentioned reason therefore, the desirable film for vapor deposition is a film manufactured by the inflation method and the cast method, which do not include the stretching. The polyethylene film manufactured especially by the cast method has about the same uniform film thickness as a stretching film, is excellent in surface flat and smooth nature, and is a suitable film.
On the other hand in high-density polyethylene, polypropylene, a polyethylene terephthalate, etc., a melting point is 130 degrees C. or more, and the dissolution/cooling energy is large. When laminating the film of the plastic by the heat-sealing method etc. with other members, a high temperature and large energy are needed and disadvantageous. When laminating a member (for example, low density polyethylene) with a melting point lower than 130 degrees C. by the heat-sealing method especially, the bad influence is remarkable. From a viewpoint of this melting/cooling energy, the desirable raw material plastic of a vapor deposition film is a low melting-point plastic like the polyethylene of low density.
However, as mentioned above, since heat resistance and size stability are demanded of the raw material plastic for vapor deposition films, plastics, such as polyethylene of low density by the high-pressure method, are not suitable.
Generally the laminate for packaging is manufactured by winding off paper or a paper substitution material layer from a raw-paper roll, sending out to a printing machine by the case, printing to the raw-paper surface, and winding the printed paper in a roll shape again, sending to an extrusion laminator, extruding fused polyolefin (for example, LDPE etc.) from an extrusion machine to the raw-paper surface, and laminate-coating between gas barrier layers, when laminating the gas barrier layers (aluminum foil etc.) other than a raw paper. Furthermore, when laminating a gas barrier layer or adding other functional layers, not all layers are laminated at once, partial laminates (pre-laminates) are prepared separately, respectively, for example, these partial laminates are further laminated by the in-line, and a final laminate is obtained.
However, LDPE used there is low density polyethylene obtained by the high-pressure method. The low molecular weight component contained in high-pressure method low density polyethylene shifts to the opposite surface to be laminated in the condition of being temporally made a roll shape. The shifted components in opposite surface may hinders the good adhesive property of heat-seal. And the flavor/taste of the product will deteriorate, when this low-molecular-weight component bleeds for the liquid product in the paper container after filling and preserves at a long period of time.
At the time of manufacture of the laminate for packaging, coating of anchor-coat material, the corona treatment to a laminating surface or/and, the lamination by adhesives resins, such as comparatively expensive EMMAA, etc. are pretreated to the material surface with poor adhesive, if needed. For example, when anchor-coat material is pretreated and laminated, the line speed of a manufacture line is 200-250 m/min.
The laminating surface which is not pretreated by the above and which has poor adhesive property may cause peeling of packaging container wall.
This invention was made based on the above-mentioned background. The purpose of this invention is offering new manufacturing method of the laminate for packaging material which can use the metal vapor deposition film containing the plastic which has heat resistance at the time of the metal vapor depositing process, and is excellent in adhesive ability with other members of a laminate, can totally or partly omit the pretreatments in the manufacture (laminating) process of packaging material, and can be manufactured at high speed.
Another purpose of this invention is offering the laminate for packaging material which can keep up the laminating intensity between layers of a packaging laminate strongly, has an optical shading performance, is excellent in a gas barrier, has a low-temperature sealability, has the metallic tone excellent in packaging appearance when the outside of packaging material laminates the aluminum vapor deposition film, and can show a good printing design.
DETAILED DESCRIPTION OF THE INVENTION
The above-mentioned subject is solved by the manufacturing method of the laminate for packaging material and the laminate for packaging material according to this invention.
The manufacture method of the material laminate for packaging is characterized by manufacturing the web shape packaging laminate which comprises of, at least ,a printing ink outer layer, a aluminum vapor deposition film layer containing the linear low density polyethylene obtained from a polymerization using metallocene catalyst, polyethylene/extrusion lamination layer, and a carrier layer of paper or paper substitution material at the following steps:
a step of vapor-depositing aluminum on one side of the web shape film containing the linear low density polyethylene obtained by the polymerization using the metallocene catalyst,
a step of winding up temporarily the resultant aluminium vapor deposition film containing the linear low density polyethylene by the polymerization using the metallocene catalyst in a reel form,
a step of keeping the reel for predetermined time to di
Frisk Peter
Kobayashi Norio
Burns Doane , Swecker, Mathis LLP
Jackson Monique R.
Tetra Laval Holdings & Finance S.A.
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