JP2001030383A - Paper cup and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a number of blanks free from slipping even when they are piled up, to arrange the folding positions to be uniform positions for all the blanks, and to make the height of the side wall of a paper cup uniform, by folding back the lower side of a barrel wall to the inner surface of the barrel wall with a half-cut line cut from the inside as a folding line. SOLUTION: In the punch-molding of a barrel wall blank at a position of a surface to be the inside of a cup separated at a distance W 7-35 times as large as the thickness Q of paper from a bottom side end fringe 12, a half-cut line 13 is cut simultaneously. The whole circumferential fringe of a bottom wall 9 is folded by a length corresponding to the distance W to the side of a bottom lower surface to form a folding side 14 for fixing. The lower side 15 of a barrel wall blank molded in the shape of an inverse cone is folded from the inner surface side of the barrel wall as a standard line, and the folding side 14 is held between the inner surface 16 of the barrel wall and the inner surface of the lower side facing the inner surface 16 and bonded/fixed to form a hem wall 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

2. Description of the Related Art A paper cup formed of cardboard as a main material and made of a paper material whose inner surface and / or outer surface has been subjected to a water-resistant treatment is folded near the lower edge of the inner surface of the body wall for fixing the bottom wall. Creases for bending the piece are formed by pressing to make the folded piece easier to bend.

However, as shown in FIG. 8, when the crease C is pressed and formed on the inner surface B of the blank A, the protrusions E are formed on the outer surface D of the blank A due to the recesses of the crease C. Is formed.

[0003] The existence of the convex portion E is determined by the height of the convex portion E when a large number of blanks in the body of the paper cup are stacked.
There is a problem that the creasing forming side becomes high and the stacked layers are liable to slip when the sheet is set in an automatic molding machine, thereby lowering the work efficiency.

The crease C has a longitudinal section perpendicular to the length direction of an arc surface having an arc length of 0.2 to 0.3 mm. When the one side piece H of the crease C is bent in the direction of the arrow X due to the density being higher than the fiber density, it becomes uncertain which position in the arc of the crease C is to be bent, and the height of the folded piece When the bottom wall is fixed by the folded pieces, there is a problem that the height of the hem wall described later and, consequently, the height of the paper cup become uneven.

[0005] It is proposed to shorten the arc length of the crease. However, from the viewpoint of bending workability, it is not only impossible to reduce the arc length to less than 0.2 mm but also to reduce the arc length to 0.1 mm.
Creed dies less than 2 millimeters are not produced because they are difficult to manufacture.

Further, in the crease C, if the body wall is a cylindrical shape having a large radius, the folded piece is easily bent. However, for example, as shown in FIG.
Not only is it difficult to bend when there is an arcuate surface portion p with a small radius r at a corner, but also there is a problem that many large wrinkles are generated on the inner surface of the bend and the commercial value is reduced.

As a more serious problem, as shown in FIG. 6, a virgin pulp J is laminated on both sides of a recycled pulp I and a surface coat layer K is formed on the outer layer of the pulp. As shown, virgin pulp M is superimposed on the outer surface of recycled pulp L, and surface coat layer N
In the case of the structure where is formed, when the arc length is bent at the crease C having a length of 0.2 to 0.3 mm, the layer length of the regenerated pulp I, L is reduced due to the short fiber length of the regenerated pulp I, L. Also, there is a problem that delamination occurs in the film and the possibility of occurrence of defective products is great.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the conventional paper cup and the method of manufacturing the same, the present invention provides a method of forming a paper cup blank on which a large number of blanks are stacked even if a folding guide portion is formed. In addition, slip does not occur in the stacking layer,
Further, one of the problems to be solved is to provide a paper cup in which the bent portion of the bending guide portion is located at a uniform position for all blanks, and the height of the hem wall of the formed paper cup is made uniform, and a method for manufacturing the same. I have.

The present invention also provides a paper cup having a high commercial value and a method for producing the paper cup, which can also bend the folded piece on the lower side of the body wall of the arc surface portion having a small radius without causing wrinkles on the bent inner surface. Is a second problem to be solved.

Further, the present invention provides a paper cup in which delamination does not occur in a recycled pulp layer even when folded pieces are bent using a laminated stock such as recycled pulp and virgin pulp, and a method for producing the same. Is the third problem to be solved.

[0011]

According to the first aspect of the present invention, in order to solve the above-mentioned problems, in a paper cup mainly made of cardboard and having at least a body wall and a bottom wall, the lower side of the body wall is The half-cut line cut from the inner surface is folded back to the inside of the trunk wall as a folding line, and between the inner surface of the trunk wall,
The fixing piece at the periphery of the bottom wall is fixed to form a skirt wall of the cup.

According to the second aspect of the present invention, in order to solve the above-mentioned problem, the forming step of the body wall in the method of manufacturing a paper cup includes the step of punching a body wall blank of the cup from cardboard base paper, the surface of the blank being inside the cup. At a distance selected from the bottom edge of the blank within a range of 7 to 35 times the paper thickness of the blank, parallel to the bottom edge, over the entire length of the body wall blank, A half-cut line was cut, and then a step of forming the trunk wall blank into a cylindrical shape was performed.

Subsequently, the step of forming the bottom wall blank and the step of assembling the body wall blank and the bottom wall blank are performed by setting the entire periphery of the bottom wall previously punched and formed to the bottom edge of the body wall blank. A bottom wall which is bent toward the lower surface of the bottom by a length corresponding to the length between the half-cut line and is formed into a folded piece for fixing is formed in a cylindrical shape, and is disposed in a body wall blank. The lower side between the bottom edge and the half-cut line of the blank was folded back toward the inside of the body wall, and the folded piece for fixing the bottom wall was sandwiched between the inside of the body wall, adhered and fixed. .

[0014]

1 to 4 show an embodiment of a paper cup 1 according to the first aspect of the present invention, which is manufactured according to the second aspect of the present invention. FIG. 3 and FIG. As shown, a body wall 6 formed into a truncated inverted conical shape by a body wall blank 5 in which water resistant layers 3 and 4 made of a synthetic resin such as polyethylene are formed on both sides of a cardboard 2, and the water resistant It is formed of the layers 3 and 4 and the bottom wall 9 on which the same kind of waterproof layer 8 is formed.

Hereinafter, the structure of the paper cup 1 according to the first aspect of the invention will be described while describing the method of manufacturing the paper cup 1 according to the second aspect of the invention.

The body wall 6 of the paper cup 1 is formed on both side edges 1 of a body wall blank 5 punched and formed into a fan shape as shown in FIG.
0 and 11 are bonded to each other to form a truncated inverted conical shape.
A depth within 50% of the paper thickness from the bottom edge 12 to a position having a length W selected within a range of 7 to 35 times the paper thickness Q of the blank shown in FIG. Now, in parallel with the bottom edge 12, over the entire length of the body wall blank 5, FIG.
Are cut at the same time.

Since the cutting blade of the half cut line 13 has a sharp cutting edge, the half cut line 13 is formed in a V-shaped cross section as shown in FIG.

On the other hand, the entire peripheral edge of the bottom wall 9 that has been stamped and formed in advance is formed on the bottom lower surface by a length corresponding to the distance W between the bottom edge 12 of the body wall blank 5 and the half cut line 13. The bottom wall 9 on which the folded pieces 14 are formed is equivalent to the bottom of the body wall blank 5 formed into a truncated inverted conical shape as described above. Then, the lower side 15 of the bottom edge 12 of the body wall blank 5 and the half cut line 13 is
Is folded back from the inner surface side of the body wall 6 as a reference line for the return, and the fold-back piece 14 for the bottom surgery on the inner wall 16 of the body wall 6
And a synthetic resin forming a water-resistant layer sandwiched between the inner surface of the lower side 15 facing the surface 16 and adhered and fixed with heat-sensitive adhesiveness, forming the hem wall 17 and forming the paper cup 1 Is completed. Due to the length of the interval W between the forming positions of the half-cut lines and the cutting depth, the delamination of the paper layer and the cutting at the half-cut line position at the time of folding do not occur.

According to the manufacturing method of the second aspect, since the lower side 15 is folded with the sharp center line of the half-cut line 13 as a reference for bending, the body wall is a folded part from the opening end 18 of the body wall 6. 6, the length to the lower edge 19 is uniform within the same lot, and the folded lower side 15 has less wrinkles, the appearance is good, and the half-cut line is reproduced at the folded portion as a reference. Even if the pulp layer is present, delamination does not occur in the layer, and the quality of the paper cup can be improved.

Further, since the delamination does not occur and the folding is performed with the center line of the half-cut line as a reference for bending, the rigidity of the lower end edge of the hem wall 17 is improved and the hem wall 17 is placed on a flat surface. The posture is stabilized, and there is no water seepage from the lower end of the hem wall due to the generation of cracks in the water cutoff layer, which is likely to occur when folded due to creases, and a high-quality paper cup can be provided.

[0021]

According to the first aspect of the present invention, the folded line of the folded portion of the lower side of the body wall upwardly on the inner surface for holding and fixing the folded piece for fixing the peripheral edge of the bottom wall is formed by the body wall. Since it is a half-cut line formed on the inner surface, and no protrusion is formed on the outer surface of the body wall of the half-cut line forming portion,
Even when a large number of body wall blanks are stacked, a perfect horizontal posture is maintained, and there is an effect that the collapse of the stacked posture does not occur.

Further, the bent portion becomes a cut line portion formed by the sharp cutting edge of the section of the half-cut line, and the bent portions of all the blanks become uniform positions. As a result, the bent portion is formed by the open end of the trunk wall and the bent portion. In this case, the distance from the lower end edge of the body wall becomes uniform within the same lot, and the quality of the paper cup can be improved.

Further, since the folding is performed based on the deepest portion of the half-cut line, an excessive tensile force is not applied to the constituent fibers of the paper layer at the folded portion, so that the recycled pulp layer is temporarily included in the blank constituting paper layer. Is present,
There is an effect that the quality of the paper cup can be improved without delamination.

In addition, it is possible to smoothly turn the folded piece in a direction perpendicular to the generatrix direction on an arc surface having a small radius in the direction of folding with respect to the half-cut line, and furthermore, the folded piece is less likely to be wrinkled. It also has the effect of improving productivity and quality.

According to the second aspect of the present invention, the position of the half-cut line formed on the inner surface side of the cup of the blank is selected within a range of 7 to 35 times the paper thickness of the blank from the bottom edge of the body wall blank. Therefore, even if recycled pulp exists in the thickness of the body wall blank, delamination does not occur, and accurate folding at a specified position can be realized. There is an effect that can be performed in a state in which the occurrence is small.

If the cut position of the half-cut line is less than seven times the paper thickness of the blank, delamination of the paper layer is likely to occur at the time of folding, and in particular, delamination of the paper layer of the recycled pulp becomes remarkable.

If the cut position of the half-cut line exceeds 35 times the thickness of the blank, the shape becomes a raised bottom shape,
Not only does the quality of the final product deteriorate, but also the amount of paper is wasted.

Also, since the turning is performed with reference to the deepest part of the half-cut line formed by the cutting of the sharp cutting edge, the upper edge and the interval of all the blanks, that is, the opening edge of the paper cup and the lower edge of the body wall are different from each other. Is maintained uniformly by the cut of the half-cut line, so that there is an effect that a high-quality paper cup can be performed with high efficiency without extra steps or devices.

As described above, by preventing delamination of the paper layer at the time of folding, the water resistance of the lower end of the hem wall is completely maintained, and the infiltration of water or the like from the lower end into the hem wall is completely prevented. It also has the effect of improving the quality of the paper cup.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a half section of a paper cup as an example of an embodiment.

FIG. 2 is a reduced development view showing an inner side surface of a body wall blank of the paper cup shown in FIG.

FIG. 3 is a schematic enlarged new view showing a cut portion of a half cut line.

FIG. 4 is a schematic enlarged new view showing a part of the folded-in fixing structure between the hem wall and the bottom wall, in order to clarify the structure, in which there is a space between each part, but actually each part is shown. Are glued.

FIG. 5 is a schematic cross-sectional view of a square tubular body.

FIG. 6 is an enlarged sectional view schematically showing a paper layer having a recycled pulp layer.

FIG. 7 is an enlarged sectional view similar to FIG. 6 of a different paper layer having a recycled pulp layer.

FIG. 8 is a schematic enlarged sectional view of a paper layer on which a cruise is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper cup 2 Cardboard 5 Body wall blank 6 Body wall 9 Bottom wall 12 Bottom edge 13 Half cut line 14 Folding piece 15 Bottom side 16 Inner surface 17 Hem wall Q Blank paper thickness W interval

Claims (2)

[Claims] 1. A paper cup having cardboard as a main material and having at least a body wall and a bottom wall formed, wherein a lower side of the body wall is directed toward a body wall inner side using a half-cut line cut from the inner surface as a folding line. A paper cup that is folded back and that has a folded piece for fixing the peripheral edge of the bottom wall between the inner surface of the body wall and the hem wall of the cup. 2. A blank having a length selected from 7 to 35 times the paper thickness of the blank from the bottom edge of the inside surface of the cup when punching the cup body blank from the cardboard. At a position with an interval between them, parallel to the bottom edge,
A half-cut line is cut over the entire length of the body wall blank, then the body wall blank is formed into a cylindrical shape, and the entire peripheral edge of the bottom wall that has been stamped and formed is half of the bottom edge of the body wall blank. Disposing a bottom wall formed on the lower surface of the bottom by a length corresponding to the length between the cut line and a bent piece for fixing in a cylindrical wall blank formed in a tubular shape; The lower side between the bottom edge and the half-cut line is folded back toward the inside of the body wall, and the fixing piece for fixing the bottom wall is sandwiched between the inside of the body wall, adhered and fixed. Manufacturing method of paper cup.