JP2593400B2 - Vulcanized fiber sheet with saw blade, carton to which the sheet is bonded, and bonding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet with a saw blade for cutting a so-called cooking sheet such as a wrapping film, paper or metal foil made of synthetic resin, a carton case to which the sheet with a saw blade is adhered, and a carton case. The present invention relates to a method of adhering a sheet to a carton case, and particularly to an invention characterized by utilizing a thermoplastic resin having a good hot tack property, which is suitable for performing ultrasonic welding easily and at high speed.

[0002]

2. Description of the Related Art A material generally called a cooking sheet, such as a synthetic resin wrapping film or aluminum foil used for packaging foods in a kitchen or the like, is usually wound into a roll. In a carton case made of paperboard (hereinafter simply referred to as a carton). In use, after the end of the film or the aluminum foil is pulled out of the carton, a cutting blade attached to the front portion or the lid of the carton, that is, a cutting blade formed in a saw-tooth shape (hereinafter referred to as a cutting blade) , Simply referred to as a cutting blade or saw blade).

[0003] By the way, the cutting blades attached to the carton are generally made of metal, but recently, those made of vulcanized fiber have been put on the market. If it is a metal cutting blade, it is easy to hurt your fingers when grabbing the carton, but if it is made of vulcanized fiber, there is no such worry, while when you finish using the film or foil, the carton is incinerated This is because disposal is possible.

[0004] However, the cutting edge made of vulcanized fiber has the above-mentioned advantages, but has the drawback that when it is placed in a humid atmosphere for a long period of time due to the properties peculiar to the material, it elongates due to moisture absorption. Have. The elongation due to moisture absorption causes local peeling between the cutting blade and the carton to which the cutting blade is adhered, resulting in a problem that the function of the cutting blade is reduced. Therefore, recently, for the purpose of remedying the above-mentioned drawbacks, after forming a moisture-proof coating made of a low moisture-permeable polyethylene resin film or the like on one or both sides of a vulcanized fiber which is a raw material of the sawtooth blade, the sawtooth blade is formed. It is made to be processed.
Invention of No. 78914 and invention of Japanese Patent Application No. 4-316253).

On the other hand, when attaching the saw-tooth blade to the carton, a thermoplastic synthetic resin film formed in advance on the surface of the saw-tooth blade under the above-mentioned reason is used, and the saw-tooth blade is formed by means of ultrasonic welding. The bladed sheet was bonded to the carton. This is because not only the thermoplastic synthetic resin film has the effect of improving the hygroscopicity of vulcanized fiber (hereinafter sometimes abbreviated as VF), but also as an adhesive medium for welding the sawtooth blade to the carton. Was also available. Therefore, conventionally, what kind of resin should be used has not been particularly studied, and based on the knowledge that it is sufficient to use a resin that easily melts, there is no detailed examination of physical properties, The fact was that general-purpose polyolefin films such as polyethylene and polypropylene were used.

Subsequently, according to the results of various studies conducted by the present inventors, it has been found that ultrasonic welding cannot be performed quickly and reliably simply by using a meltable resin. That is, when the material itself is a composite material of paperboard and a thermoplastic resin, as in the case of the carton case with a saw blade, the ultrasonic vibration energy is partially absorbed by the paperboard during ultrasonic welding, and the adhesive is bonded. It was found that the resin film as the medium was not sufficiently melted and the welding efficiency was reduced.

Therefore, the present invention solves the above-mentioned problems in attaching the vulcanized fiber sawtooth blade having the above-mentioned structure to a carton, and performs the attaching operation at a much higher speed than in the past. It is intended to be able to.

[0008]

That is, in the present invention, a resin suitable for the composite material having the above-described structure and having excellent hot tack property at the time of ultrasonic welding is specified. The resin enables ultrasonic welding in a short time and with a sufficient welding strength.
Examples of the resin having a good hot tack property include a modified polyethylene resin such as an ethylene-vinyl acetate copolymer (EVA), an ethylene-methacrylic acid copolymer (EMMA), or an ionomer mainly composed of an ethylene resin. Can be used alone or as a mixture.

The resin having excellent hot tack properties is extruded from the VF by extrusion lamination.
A resin film on both sides or one side of the VF, or apply the resin as an emulsion or dispersion on the surface of the VF, and then form a resin film or a coating film on the VF and the carton blank. And ultrasonic oscillation is applied by the horn simultaneously with pressurization by the ultrasonic horn. At that time, frictional heat is generated at the interface between the carton and the VF. That is, the friction generates heat instantaneously, thereby melting and bonding the resin.

As described above, according to the present invention, after the resin having good hot tack property as described above is applied to at least either the surface of VF or paperboard, the surface of the resin is welded to the object to be welded using ultrasonic vibration energy. By utilizing the frictional heat generated between the two, a hot tack property is exhibited, whereby the two are quickly and firmly welded. In particular, the ionomer containing ethylene resin as a main component used in the present invention is:
Modified polyethylene resin (Surlyn, trade name, manufactured by DuPont) having a cross-linked structure of metal ions between molecules has high melt tension due to ionic cross-linking during cooling and solidification after ultrasonic welding, and therefore has a high hot tack property. Is outstandingly excellent.

Incidentally, the hot tack property referred to in the present invention is a property showing a dynamic sealing property and is characterized by an extremely short time sealing property, and is a useful property for ultrasonic welding. This is a concept for heat seal strength, which indicates an advantageous behavior when a peeling force is applied to a welded portion and indicates a seal strength while the portion is not sufficiently solidified, that is, a so-called static sealability after solidification.

In short, the present invention is characterized by using a resin having a high dynamic seal strength as described above.
Each of the above-mentioned modified polyethylene resins is superior in dynamic seal strength as compared with other resins, and is a resin having a good hot tack property, so that it was composed of a composite material of vulcanized fiber and a resin film. In adhering the sheet with saw blades to the carton case made of paperboard, it is very effective to use a modified polyethylene resin having the above properties.

As a method of application, a low-moisture-permeable moisture-proof coating made of a modified polyethylene resin is directly formed on both sides or one side of the VF raw material constituting the sheet with a sawtooth blade as described above, or With another resin film interposed, a modified polyethylene resin film may be formed as the uppermost resin film. By the way, the above-mentioned modified polyethylene resin plays a role as a moisture-proof film itself, but after forming a moisture-proof resin film selected from other polyolefin resin, polyester resin or polyvinylidene chloride resin on the vulcanized fiber surface. Alternatively, the modified polyethylene resin film may be formed in a superimposed manner.

Prior to forming each of the above-mentioned moisture-proof coatings on the surface of the vulcanized fiber, a melamine resin, glyoxal or other water-proofing agent is applied in advance and subjected to a so-called water-proof or water-proof treatment. May be formed.

The shape of the entire cutting blade in the sheet with a sawtooth blade may be a straight line, or the entire cutting blade may be bent in the longitudinal direction to form a mountain shape.

As described above, in the present invention, a vulcanized fiber piece having a sawtooth blade formed thereon, that is, a sheet with a sawtooth blade is attached to the above-mentioned carton. A sheet with a saw blade is superimposed on a sheet of paper to constitute, and then a sheet with a saw blade and a moistureproof film formed on the surface of the sheet by an ultrasonic welding method, particularly a film made of the modified polyethylene resin. Are bonded to each other, and it has been confirmed that the adhesive bonded in this manner does not peel off at all even when placed in an atmosphere of high humidity.

Thus, the present invention makes it possible to maintain a vulcanized fiber sheet with saw blades in a state that is less susceptible to the effects of humidity. Since it becomes a sheet, the cutting performance of the saw blade is high, and even when this sheet is bonded to a carton, there is no risk of peeling at the bonding site,
Moreover, it is possible to provide a carton with cutting teeth firmly bonded.

The main material used in the present invention is vulcanized fiber. As is well known, a base paper made by using cotton fiber or chemical pulp as a raw material and having no size is prepared at a predetermined concentration (generally a degree of Baume of 65 to 74). It has been treated with a zinc chloride solution, and has an intermediate property between wood and metal.
It has high elasticity and rigidity, is much lighter than metal, and has high resistance to various oils.

The present invention makes use of the above-mentioned properties of vulcanized fiber, and by subjecting this to special processing as described below, obtains the above-mentioned sheet with a sawtooth blade, which is adhered to a carton to obtain a conventional sheet. It is intended to provide a carton with a cutting blade which is highly useful in place of a metal blade. Further, the thickness of the sheet with a saw blade is about 0.2 mm to 0.5 mm, preferably 0.25 mm to 0.
Approximately 35mm, thinner, sharper.

In the present invention, the raw material of the above-mentioned vulcanized fiber may be used as it is as a raw material of a sheet with a sawtooth blade, but the vulcanized fiber is previously coated with a melamine resin solution or a glyoxal solution or the like. Alternatively, it may be used after being impregnated to impart water resistance.

The method for forming the moisture-proof coating provided on the surface of the raw material is specifically described below. The modified polyethylene-based resin having low moisture permeability is prepared in the form of an emulsion or a solution.
A method of applying to the surface of the raw material, a method of dry laminating in the form of a film, or a method of extruding and coating the surface of the raw material while holding each of the resins in a molten state is adopted. can do.

Among them, ethylene vinyl acetate copolymer,
Ethylene-methacrylic acid copolymer, a method of laminating a modified polyethylene resin such as an ionomer by melt extrusion, laminating on the surface of vulcanized fiber, or a method of laminating a film of the modified polyethylene resin after melt-extruding the polyethylene resin Is good.

When the sheet with the sawtooth blade having the above-mentioned structure is adhered to a carton blank, an emulsion or solution of polyethylene or a modified polyethylene resin is used as an adhesion promoter on the carton side of a portion corresponding to the adhesion site. If you apply in advance to form a film,
The bonding strength between the two is further increased.

[0024]

Hereinafter, the present invention will be described more specifically based on Examples and Comparative Examples. Example 1 First, a method for producing a raw material of vulcanized fiber will be briefly described. NBKP and NDS used as pulp
Using a stock containing 50% each of P,
A base paper of 05 g / m2 is made. 69 °
Baume, immersed in a zinc chloride solution at 40 ° C., squeezed, heated and pressed, and air-aged to elute about 30 ° Baume zinc chloride. Next, after pickling in a hydrochloric acid tank, the mixture is sent to a water washing tank to remove zinc chloride. After pre-drying,
The melamine formalin resin solution is applied on both sides (10 g / m 2 in terms of solid content) and dried with a cylinder dryer. Next, calendering was performed and 0.25m
An m-thick vulcanized fiber raw material having high water resistance was obtained.

After coating and drying polyethyleneimine at a solid content of 3 g / m 2 on each of the front and back surfaces of the raw material, the coated surface is subjected to anchor treatment. Extrusion coating is carried out, and on one side simultaneously with the melt extrusion coating, a thickness of 40 μm of an ethylene-vinyl acetate copolymer (Ultracene 2077R manufactured by Tosoh Corporation), which is a modified polyethylene resin, is formed on the polyethylene resin layer in a molten state. By laminating the above films, a moisture-proof film having both moisture-proof property and hot tack property was formed.

Thus, as shown in FIG. 2 and FIGS. 4 and 5, a moisture-proof coating 2 composed of a low-density polyethylene layer is formed on both the front and back surfaces of the strip-shaped raw material 1 of vulcanized fiber, and a modified polyethylene resin is formed on one surface thereof. A vulcanized fiber board 4 formed by forming a resin film 3 having excellent hot tack properties is obtained. Next, if this fiber plate 4 is set on a saw blade forming machine or stamped and formed by a press machine or the like, the saw blade 5a as shown in FIG.
Is obtained, and a sheet 5 with a sawtooth blade made of vulcanized fiber is formed.

Table 1 shows the results of a comparative test on how much the installation time of the saw blade with respect to the carton, in other words, the mounting speed is increased by the difference between the resin having excellent hot tack property and the resin having not excellent hot tack property according to the present invention. It is a thing.
That is, as a resin having excellent hot tack properties, an ethylene-vinyl acetate copolymer (Ultracene
2077R) ... EVA is indicated in the table ... and ionomer containing ethylene resin as a main component (trade name: Surlyn 1652 manufactured by DuPont) ... In the table, ionomer is indicated ...
Each of these resin films is formed in a thickness of 20 μ and 40 μ by extrusion coating on the surface of a raw material made of vulcanized fiber (indicated as VF in the table), while a normal thermoplastic resin for comparison, ie, Ordinary low-density polyethylene resin (Polysol OLX-7319 made by Showa Polymer),
In other words, after forming a resin film of the same thickness using the same method as described above using an unmodified PE resin, the mounting time of the saw-tooth blade to the carton varies depending on the type of each resin film. It was confirmed.

[Table 1] (see Attachment)

By the way, the raw material has a directionality due to the orientation of the constituent fibers during papermaking. That is, since the constituent fibers tend to be arranged in parallel along the papermaking direction,
Accordingly, the physical properties of the raw material itself differ between the longitudinal direction of the raw material, ie, the machine direction (MD direction) and the direction orthogonal to the machine direction (CD direction). In particular, considering the expansion and contraction rate during moisture absorption,
The expansion and contraction ratio in the CD direction shown in FIGS. 4 and 5 is 6 to 7 times higher than that in the MD direction. Specifically, taking elongation as an example, when the relative humidity is changed from 65% RH to 90% RH (left for 24 hours at an ambient temperature of 23 ° C.), the elongation is 0.4% in the MD direction and 2.7% in the CD direction. Indicates the value of%.

Therefore, when a sheet with a saw blade is formed from the raw material, the saw blade is formed in a state as shown in FIG. As a result, the sheet with the saw blade is bent in a wavy manner on the carton, and local peeling occurs. As a result, the sharpness of the saw blade itself is impaired and the sharpness is extremely reduced. By the way, when the saw tooth blade is formed along the direction of MD in the state as shown in FIG. 5, the above-mentioned phenomenon does not occur because the expansion and contraction rate is small. In practice, no problem arises.

The present invention can also solve the problem in the CD direction, because a moisture-proof film is formed on both sides of the raw material. According to the present invention, when the saw blade is formed on the raw material 4 processed as described above, the saw blade may be formed in any of the MD direction and the CD direction.

In the embodiment shown in FIG. 2, the first moisture-proof coating 2 is formed on both surfaces of the raw material 1, and the hot tack property of the modified polyethylene resin as shown in Table 1 is formed on one surface. After forming the high resin film 3, FIG.
In this case, a sheet 5 with a sawtooth blade having a shape as shown in FIG. 1, that is, an elongated rectangular sawtooth blade 5 is obtained. As an example, a 0.8 cm × 30 cm flat plate with a sawtooth blade having a thickness of about 0.25 mm is provided. It is a sheet. Note that the resin film may not have a two-layer structure as described above, but may be a single resin film formed of a modified polyethylene resin.

Example 2 The same treatment as in Example 1 was conducted except that a raw material of vulcanized fiber having a basis weight of 400 g / m 2 was used to form a moisture-proof coating made of low-density polyethylene on both surfaces of the raw material. Then, on one side, a resin film having a high hot tack property by a modified polyethylene resin film, that is, a resin film formed by using an ethylene-methacrylic acid copolymer (trade name: Nucrel 0903HC manufactured by Mitsui Petrochemical Co., Ltd.) The cutting blade was stamped and formed to obtain a sheet with a saw blade. In this case, the thickness of the sheet with saw blades was 0.35 mm, and saw blades were formed on two long sides of the rectangular sheet.

The modified polyethylene film having a high hot tack property in the sheet 5 with the sawtooth blade of the above-described form is subjected to corona discharge treatment to activate the film, and has a surface tension of 40 dyne / cm.
cm, the modified sheet formed on the surface of the sheet by an ultrasonic welding method, and the sheet is overlapped with the carton blank in the developed shape shown in FIG. The paperboard and the sheet with saw blade were welded together via a polyethylene coating.

Hereinafter, the structure of the carton will be described with reference to FIGS. In the figure, the symbol P indicates the US basis weight of 350
g / m2 cardboard carton blank (0.8 mm thick)
Reference numeral 11 denotes a rectangular bottom plate formed by forming a section on the blank through a folding line, and a front plate 12 is connected to a long side located below the bottom plate in the drawing, and the other long side is similar to the above. The back plate 13, the top plate 14, and the cover plate 15 are provided so as to be adjacent to each other via a bent line. Also, the front plate 12
And the back plate 13 on both sides, adhesive strips through the folding line
16 and 17 are extended, and on the other hand, the end plate 19 provided with a flap 18 on the short side of the bottom plate 11 is also extended.

It should be noted that, in the cover plate 15, as shown in the figure, a break line 20 in the shape of a letter C and a straight break line 21 connected to the cut line are engraved, and when the carton after assembly is opened, these break lines are opened. Use to open. Cover plate 15 after assembly
, That is, the portion of the temporary attachment piece 23 surrounded by the break line is opened by cutting off the carton main body, and at the same time, the insertion piece 22 formed between the C-shaped break lines 20.
After opening, the cover is fixed by inserting it into the locking slit 24 formed in the front plate 12.

The sheet 5 with the saw blade is bonded to the boundary between the bottom plate 11 and the front plate 12 on the bottom side of the bottom plate 11. When the bonding is performed, the saw blade 5a of the sheet slightly exceeds the folding line at the boundary. Fix it in a protruding position. When the sheet with the sawtooth blade is adhered to the carton, the sheet is preferably attached so that the length of the sheet is slightly shorter than the long side of the bottom plate 11 in the length direction.

In assembling the unfolded carton blank, as shown in FIG. 7, the front plate 12, the back plate 13, and the end plate 19 are vertically raised centering on the bottom plate 11 via folding lines. After bonding the adhesive pieces 16 and 17 to the inside of the end plate 19 and bonding them, the one wound in a roll shape with the above-mentioned cooking sheet (see reference numeral G in FIG. 8) is accommodated therein. Next, after the opening surface is covered with the top plate 14 and the cover plate 15, the cover plate is closed by applying spot bonding H to the front plate 12 via the temporary attaching piece 23 or the like.

When the cooking sheet F contained in the carton is taken out as described above, the temporary attachment piece 23 spot-adhered as shown in FIG. Then, the edge of the wrapping film or sheet F wound as the roll G is picked up and pulled out to a desired length. By pulling out the film etc. from the upper edge of the front plate 12 along the plate 12 and pressing it in the direction of the front plate 12,
A required length is cut by a saw blade 4a projecting from the lower edge of the front plate. After cutting, insert the insert 22
It is inserted into the locking slit 24 formed in the 12 and is operated so as to close the opening and prevent dust from entering the carton.

Example 3 Raw material of vulcanized fiber raw material having a basis weight of 400 g / m 2
The same processing as in Examples 1 and 2 was used to apply a melt-extruded coating of an ethylene-vinyl acetate copolymer, which is a modified polyethylene resin, on both surfaces of the raw material. A resin film 3, that is, a modified polyethylene resin film 3 having both moisture proof property and good hot tack property was formed.

Embodiment 4 Next, a description will be given of an embodiment in which a sawtooth blade-equipped sheet is formed in which the distribution of the sawtooth blades is not linear but exhibits a mountain shape. As clearly shown in FIG. 9, when the arrangement of the saw blades is viewed in a plan view, the sheet with the saw blades is formed of a plate-like member in a distribution state in which a central portion in a longitudinal direction protrudes and is slightly inclined toward an end. 6, which is a carton blank P 'having a developed shape substantially similar to that of the above embodiment.
This is an example of bonding to a sheet.

Hereinafter, the structure of the carton blank will be briefly described. A cover plate 25 is connected to the upper side of the top plate 14 of the blank, and a sawtooth having a form different from that of the above embodiment is provided on the cover plate surface. The sheet 6 with the blade is adhered, and a break line 26 having a shape according to the form is engraved on the cover plate. Then, in taking out the roll-shaped film or sheet stored in the carton, the separating piece 27 located outside the breaking line 26 is removed along the breaking line, and the carton is opened. Operate as follows. When the separation piece 27 is separated from the cover plate 25, the portion of the saw blade 5a in the sheet 6 with the saw blade is exposed from the edge of the cover plate. Alternatively, the sheet can be cut to a required length. Incidentally, in the reference numerals shown in the carton blank P ', the same reference numerals are given to members common to the above-described embodiment (see FIG. 6).

A material for facilitating adhesion, for example, an emulsion of polyethylene or modified polyethylene, was preliminarily pattern-coated with a gravure coater or the like at a portion to be bonded on the carton blank side where the sheet with the sawtooth blade is bonded. When the blank is supplied to the die setting mechanism, the bonding strength by the ultrasonic bonding is further increased, and the bonding speed can be improved.

Example 5 An ionomer containing ethylene resin as a main component (trade name: Surlyn 1652 manufactured by DuPont) was laminated on both surfaces of a sheet with a sawtooth blade (308 g / m 2 vulcanized fiber) to a thickness of 30 μm. It was mounted on a carton case blank (white paperboard of 350 g / m 2) by sonic welding. The bonding time was as short as 0.2 seconds, and the bonding was performed with sufficient bonding strength. Similar results were obtained when an ethylene-methacrylic acid copolymer (trade name: Nucrel 0903HC manufactured by Mitsui Petrochemical Co., Ltd.) was used instead of Surlyn.

COMPARATIVE EXAMPLE The procedure of Example 5 was repeated except that a low-density polyethylene resin (trade name: Mirason 16P manufactured by Mitsui Petrochemical Co., Ltd.) was used instead of Surlyn 1652. In seconds, sufficient adhesive strength could not be obtained. Incidentally, as a hot tack measuring device, there is a hot-peelability measuring device manufactured by Tester Sangyo Co., Ltd., and the above-described test was performed using this device.

Considering the reason why the modified polyethylene resin used in the present invention is excellent in hot tack property, factors of the hot tack property include the heat sealing property itself and the solidification point of the resin which influences the time until the sealing portion solidifies. It is considered that it depends on the crystallinity of the resin, that is, the density, which affects the peel resistance at the time of semi-melting. In general, since the melt tension is related to the MI of the resin, it can be said that the lower the MI and the higher the density of the resin, the better the hot tack property. Therefore, a resin suitable for the present invention can be selected based on these. The hot tack property is also referred to as hot sealing property, and the methods for measuring the hot tack property include a peeling force method and a peeling distance method. Stop at the location).
It was confirmed that each of the above resins was superior to unmodified polyethylene in both of these physical properties, and was suitable for ultrasonic welding.

Although the present invention has been described in detail, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. Next, in order to confirm that the resin film according to the present invention also exerts an effect as a moisture-proof film, the following test was performed using the following samples. [Sample A] A melamine resin solution (5%) was previously prepared on a raw sheet (Vulcanized fiber plate (0.35 mm thick) having a basis weight of 400 g / m @ 2 of rice) prepared according to Example 2 above.
% Concentration) and then dried. A polyethylene film with a thickness of 20μ is formed on both sides of the raw material, and a 40μ ethylene-vinyl acetate copolymer film is further laminated on one side. [Sample B] A vulcanized fiber plate (the same thickness) having the same rice basis weight as that described above, which was previously impregnated with a melamine resin solution (5% concentration). [Sample C] A 5% melamine resin solution was impregnated in advance into a vulcanized fiber plate having the same rice basis weight (the same thickness) as above, and then 15 g of a urethane resin solution was further impregnated.
/ M2 (solid content).

From the raw material of each of the samples, a width of 8 m was used.
m, a rectangular plate having a length of 100 mm was cut out. In the cutting, as shown in FIGS. 4 and 5, the direction in which the saw blade is formed is set to the length direction, and the length direction is set to MD.
The direction parallel to the direction (indicated as “vertical” in Tables 2 and 3) and the direction in which the CD direction matches the length direction of the saw blade.
(Also indicated as “horizontal” in the table) and tested how much expansion and contraction occurred in each of the samples due to differences in humidity.

The test method was as follows:
Each sample was left standing for 24 hours in an atmosphere of 65 ° C. and 65% RH, and the elongation in the length direction of each sample was measured to obtain a reference value. Then, each of the samples to be measured was 20% R
H and 90% RH, and the degree of expansion and contraction when left for a predetermined time (each time described in the table),
The following Tables 2 and 3 show the percentages of elongation or shrinkage with respect to the measured values when the conditions were changed, expressed as percentages.

[Table 2] (see Attachment)

[Table 3] (see Attachment)

As is clear from Tables 2 and 3, according to the present invention, the vulcanized fiber plate which is relatively easily affected by the moisture in the atmosphere is also hardly affected by humidity due to the moisture-proof coating formed on the surface thereof. It was confirmed that it could be maintained. In particular, the moisture-proof treatment by the formation of the moisture-proof coating of the present invention is remarkable in that it shows a remarkable effect as compared with the conventional products, as compared with the conventionally used water-resistant products made of melamine resin or urethane resin.

Further, according to the present invention, the use of the moisture-proof coating makes it possible to use a mild treatment even in the case of waterproofing or waterproofing with a melamine resin or a urethane resin, which has been indispensable conventionally. There is no need to use expensive urethane resin, and as a result, it is extremely advantageous in that a low-cost and highly practical product can be provided. That is, when comparing modified polyethylene, for example, vulcanized fiber laminated with an ethylene-vinyl acetate copolymer and that coated with urethane resin, the former at the unit price of the resin used is not only the half value of the latter, but also at the processing speed, The former is the latter 30
It is highly efficient, and when it is adhered to a carton, it uses a modified polyethylene resin with high hot tack properties, so no other adhesive is required and ultrasonic fusion bonding is possible, so it is desirable. Can be provided at a very low price.

[0051]

Thus, the present invention uses a vulcanized fiber plate on which the above-mentioned moisture-proof coating is formed as a raw material, and forms a sawtooth blade on the fiber while utilizing the extremely high elasticity and rigidity of the fiber itself. As a result, the saw blade is not deformed or crushed by an external force, and always exhibits sharp cutting performance. In particular, the sheet according to the invention is:
Cooking sheets made of resin film, paper, metal foil, processed paper, etc. used for food packaging, as they do not impair dimensional stability even in kitchens or kitchens where the humidity in the atmosphere is high. It is suitable as a cutting blade for cutting off.

In addition, since the sheet with the sawtooth blade is made of vulcanized fiber, even when used with being attached to a carton, it does not damage the fingertips during handling, and furthermore, becomes used. Can be incinerated as it is, and there is no residue like a conventional metal blade.

Furthermore, when the sheet with saw blades of the present invention is attached to a carton, there is almost no difference in expansion and contraction even when exposed to moisture in the atmosphere. There is no relative difference in expansion and contraction between the sheets, so the sheet with a saw blade after being attached to the carton does not peel off or deform under the influence of humidity, and therefore has a stable cutting function at all times Demonstrates the advantage of exhibiting.

In addition, according to the present invention, the surface of the vulcanized fiber plate is formed by using a modified polyethylene resin having not only a moisture-proof function but also a melting point lower than that of a normal polyethylene resin and a high adhesiveness as a moisture-proof coating. As a result, not only the moisture-proof function is strengthened, but also the effect of shortening the time for mounting on the carton blank and reducing the manufacturing cost is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a sheet with vulcanized fiber sawtooth blades according to the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged sectional view showing another embodiment of a sheet with saw blades made of vulcanized fiber in the present invention.

[FIG. 4] After a moisture-proof coating is formed on both sides of a raw material of vulcanized fiber, a saw blade is formed on the raw material in a direction perpendicular to the papermaking direction of the raw material (CD direction = Cross Direction) to form a sheet with a sawtooth blade. FIG.

FIG. 5 is a view showing a sheet having a saw blade from the raw material.
FIG. 4 is a plan view showing a case where a saw blade is formed parallel to a paper making direction (MD direction = Machine Direction) of the raw material.

FIG. 6 is a developed view showing one embodiment of a carton blank provided with the sheet with a sawtooth blade.

FIG. 7 is a perspective view showing a state where the carton blank shown in FIG. 6 is assembled and opened.

FIG. 8 is a perspective view showing a state in which, after opening the carton, the cooking sheet wound into a roll and stored in the carton is pulled out and cut.

FIG. 9 is a developed view showing another embodiment of the carton blank to which the above-mentioned sheet with a vulcanized fiber sawtooth blade is adhered.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Raw material 2 Resin moisture-proof film 3 Hot tack resin film 4, 5 Sheet with a saw blade 5a Saw blade 11 Bottom plate 12 Front plate 13 Back plate 14 Top plate 15 Cover plate 16, 17 Adhesive piece 19 Wife plate 20 Break line 22 Difference Filling piece 23 Temporarily attaching piece 24 Hook slit 26 Break line

Claims (6)

(57) [Claims] 1. A sheet in which a moisture-proof coating comprising a modified polyethylene resin coating having excellent hot tack property is formed on one or both sides of a vulcanized fiber raw material,
A vulcanized fiber sheet with a sawtooth blade having at least one edge processed into a sawtooth blade shape. 2. The vulcanized fiber saw blade according to claim 1, wherein the moisture-proof coating is a resin coating having low moisture permeability composed of a polyethylene resin, and a modified polyerylene resin having excellent hot tack property is laminated on the resin coating. Sheet with blade. 3. The vulcanized fiber raw material is coated with a melamine resin, glyoxal, or other water-resistant agent on the surface thereof, and then the moisture-proof coating is formed.
Or a sheet with a sawtooth blade made of vulcanized fiber according to 2. 4. A modified polyethylene resin film on one or both sides of a bottom or a lid having a carton body composed of a bottom plate, a front plate, a back plate and a rear plate, and a lid covering an opening of the carton body. A carton made by adhering a sheet with a vulcanized fiber sawtooth blade formed with a formed moisture-proof coating. 5. The vulcanized fiber sheet with a saw blade according to claim 4, wherein the bonding site of the saw blade sheet in the carton blank is coated in advance with polyethylene or a modified polyethylene resin. A method of bonding a vulcanized fiber sheet with saw blades to a carton blank. 6. The vulcanized fiber according to claim 1, wherein the modified polyethylene resin is any one of an ethylene-vinyl acetate copolymer, an ethylene-methacrylic acid copolymer, and an ionomer containing an ethylene resin as a main component. And a carton having the sheet bonded thereto, and a method of bonding the same.