Severing by tearing or breaking – Severing by manually forcing against fixed edge – With housing for work supply
Reexamination Certificate
1996-12-02
2001-01-16
Rachuba, M. (Department: 3724)
Severing by tearing or breaking
Severing by manually forcing against fixed edge
With housing for work supply
C225S043000, C225S049000, C225S056000, C225S077000, C225S091000
Reexamination Certificate
active
06173876
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a sheet having a serrated cutting edge for cutting what is called a cooking sheet such as a wrapping film of a synthetic resin, paper sheet and metallic foil, and to a carton case to which said sheet having a serrated cutting edge is adhered. The invention also includes a method of adhering said sheet having a serrated cutting edge to said carton case. Particularly, the invention is characterized by said sheet being made of a vulcanized fiber having a special composition.
BACKGROUND ART
A material generally called a cooking sheet, such as a wrapping film of a synthetic resin and aluminum foil, used in the kitchen, etc. for wrapping foods or the like, is usually rolled up and contained in a paperboard carton case (hereinafter referred to as “carton”). At the time of use, an end of said film or aluminum foil is pulled out of the carton and cut to a desired length by means of a cutting member or a serrated cutting edge provided on a front portion or a cover portion of said carton (hereinafter referred to as “cutting edge” or “serrated cutting edge”).
The cutting edge provided on the carton is generally made of a metal. Recently a cutting edge made of a vulcanized fiber has been put on the market because while a metal cutting edge is likely to injure the hand when it is grasped, the vulcanized fiber cutting edge is free from such a possibility. Furthermore, the vulcanized fiber cutting edge may be burned together with the carton when the film or the foil has been used up.
While the vulcanized fiber cutting edge has the above-mentioned advantages, it also has the disadvantage that because of the properties of the material, the vulcanized fiber cutting edge absorbs moisture and elongates when it is put in a moist atmosphere for a long period of time. In an attempt to moisture proof the vulcanized fiber cutting edge, a vulcanized fiber blank has been coated with a melamine resin liquid, glyoxal solution, polyurethane resin liquid, etc. before a cutting edge is formed. However, none of these attempts have been very successful and further improvements are required. If the vulcanized fiber cutting edge is put in the kitchen, etc. which often has a high humidity, the cutting edge may be elongated by moisture in the atmosphere. According to the degree of water-resisting or waterproofing treatment, elongation by moisture absorption may, in an extreme case, partially separate the cutting edge from the carton to which the cutting edge is adhered and reduce the function of the cutting edge.
It is a first object of the present invention to provide a sheet for a cutting edge for cutting a material dispensed from within the carton, said cutting edge always having a satisfactory cutting function without being affected by moisture in the atmosphere. In other words, said first object of the present invention is to provide a vulcanized fiber sheet having a serrated cutting edge, said sheet having a very high dimensional stability.
It is a second object of the present invention to improve the shape of the cutting edge so that it can smoothly cut a film of polyvinyl chloride, etc. having a relatively large elongation.
It is a third object of the present invention to provide a novel method of adhering a sheet having a cutting edge to the carton, said method preventing said sheet from peeling off from the carton, even when the sheet is thin. In this method, the cutting edge can be adhered to the paperboard of which the carton is made at the same speed as when a usual metal cutting edge is attached by caulking,
DISCLOSURE OF INVENTION
The present invention solves the above-mentioned problems by forming a moisture-proof film having a low moisture permeability on the two surfaces of a vulcanized fiber sheet having a serrated cutting edge, said moisture-proof film being any one chosen from a polyolefin resin film, polyester resin film and polyvinylidene chloride resin film. Typical examples of said resin film are a polyethylene film, PET film, etc.
While said moisture-proof film may be formed directly on the surfaces of the vulcanized fiber, it is also possible to subject the vulcanized fiber to a water-resisting or waterproofing treatment, for example, by applying thereto a water-resisting agent such as said melamine resin and glyoxal before said moisture-proof film is formed.
To improve the adhesion between said moisture-proof film and said vulcanized fiber, the following means may be used: coating said vulcanized fiber in advance with an anchor coating agent such as polyethyleneimine; or subjecting a resin film to corona discharge before said resin film is applied to said vulcanized fiber so as to form said moisture-proof film.
In a usual serrated cutting edge, the shape of each cutting tooth and the distribution of the cutting teeth are of little importance. In the serrated cutting edge formed on the moisture-proof vulcanized fiber blank according to the present invention, said cutting edge has a certain length and the cutting teeth of said cutting edge are distributed straight. It has been found that if each cutting tooth in the central portion of said cutting edge has the shape of an isosceles triangle and each cutting tooth in the remaining end portions of said cutting edge has the shape of a scalene triangle inclined outward, the cutting edge can even cut well a film having a relatively large elongation.
The serrated cutting edge of the sheet may be either formed straight as mentioned above or bent angularly in the lengthwise direction.
In the present invention, the serrated cutting edge already formed as mentioned above, particularly the sides of each cutting tooth, may be subjected to the water-resisting treatment. In this case, the serrated cutting edge already formed and portions near said cutting edge are subjected to any of the following treatments. One of them is to coat or impregnate the sides of the cutting teeth with an organic solvent solution of any of the above-mentioned resins adapted to have a relatively high fluidity or with a water-resisting agent not mentioned above. Also, a waterproof film may be formed on the serrated cutting edge by applying an ionizing radiation curing resin such as an electron beam curing resin (EB resin) and an ultraviolet curing resin (UV resin) to the sides of the cutting teeth and hardening said resin. The hardened waterproof film of said ionizing radiation curing resin is very hard so that it prevents moisture from permeating through the sides of the cutting teeth and increases the strength of the cutting edge itself. Said water-resisting treatment includes waterproofing treatment for preventing the permeation of moisture.
The above-mentioned waterproof film may be formed on the sides of the cutting teeth as a second treatment after a moisture-proof film is formed on the two surfaces of the vulcanized fiber. Also, it is possible to form a moisture-proof film on the two surfaces of the vulcanized fiber blank which is permeated in advance with a waterproofing agent and then form a serrated cutting edge thereon.
In the present invention, the vulcanized fiber sheet provided with said serrated cutting edge is attached to a carton as mentioned above. The sheet may be attached to the carton by means of a suitable adhesive (including a pressure-sensitive adhesive). If the following method of adhesion is used, various superior effects as mentioned below will be obtained as compared with the case where said adhesive is used.
The method of adhesion comprises placing the sheet having the serrated cutting edge upon a piece of paperboard for the carton, and then adhering said sheet to said paperboard through the moisture-proof film on the surface of said sheet by an ultrasonic adhesion method. It has been confirmed that such adhesion is free from peeling even in a high-humidity atmosphere.
Thus, according to the present invention, it is possible to maintain the vulcanized fiber sheet having said serrated cutting edge in a state less liable to be affected by humidity. Therefore, the sheet having said serrated cutting edg
Ikeda Keiichi
Mikamo Hiroaki
Nagasawa Shiro
Sano Mitsuhiro
Shoji Isao
Flynn ,Thiel, Boutell & Tanis, P.C.
Oji Paper Co. Ltd.
Rachuba M.
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