JP2014172037A - Gravure roll for transferring hot melt adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure roll for transferring a hot melt adhesive not generating a cobwebbing phenomenon in the hot melt adhesive transferred onto a laminate material by the gravure roll.SOLUTION: The shape of a mesh-like cell (2) formed on a gravure roll (1) for transferring a hot melt adhesive is a rhombic shape in which one (A) of two facing angles is positioned on the rotation direction side, the other one angle (B) is positioned on the opposite side to the rotation direction of the roll (1), and each angle of the two angles (A), (B) is 140° respectively.

Description

  The present invention relates to a gravure roll for transferring a hot melt adhesive.

  As a lid for a cup-shaped container for food such as yogurt, a laminate material in which a polymer material and an aluminum foil are laminated is used, and a hot-melt adhesive is used to form a heat sealing material layer of the laminate material. . This hot melt adhesive has a relatively low melting point as a sealant, and is often melted and transferred with a gravure roll.

Japanese Patent No. 2587986

  Most hot melt adhesives used for food cup-shaped container lids consist of ethylene-vinyl acetate copolymer (EVA), wax, tackifiers, and other trace amounts of additives. It can be configured in various combinations depending on the performance. However, depending on the required performance such as heat resistance, a hot melt adhesive having a high viscosity is required, and it may be difficult to apply the hot melt adhesive with a gravure roll. This is because when the hot melt adhesive is transferred from the gravure roll to the laminate, the yarn is pulled in the rotation direction of the roll due to its high viscosity. This is because gravure rolls are provided with square mesh-like cells, as disclosed in the above-mentioned patent document, and hot melt adhesive is filled in these cells and transferred to the laminate material. However, when transferring, the cut from the bank that divides the net-like cells is poor, and the yarn is pulled by being dragged by the rotation of the roll. When the yarn is pulled in this way, the hot-melt adhesive after the transfer does not have a smooth loose mountain shape, but has a sharp pointed upward shape (see FIG. 5). Then, the shape sharpened upward at an acute angle has a drawback that it is difficult to handle because the total thickness becomes thick when the product is wound in a coil shape. In addition, when stringing occurs, there is a problem that the hot melt adhesive in the form of a thread adheres to the surface of the laminate material, or the sharp-angled hot melt adhesive is scraped off in a subsequent process and becomes a foreign matter. .

  In short, if the angle on the opposite side of the rotation direction of the gravure roll cell is less than 120 °, the threading phenomenon is likely to occur in the transferred hot melt adhesive.

  An object of the present invention is to provide a gravure roll for transferring a hot melt adhesive in which a stringing phenomenon does not occur in a hot melt adhesive transferred to a laminate by a gravure roll.

  The gravure roll for transferring a hot melt adhesive according to the invention of claim 1 is such that the shape of a mesh-like cell formed on the gravure roll is a rhombus or a hexagon, and one of two opposing corners is a roll. On the rotation direction side, the other angle is on the opposite side of the rotation direction of the roll, and the angles of the two angles are both 120 ° to 160 °.

If the angle is less than 120 °, the hot melt adhesive may be pulled from the gravure roll to the laminate, and the yarn may be pulled in the direction of roll rotation. When transferring the agent, the cut off from the bank portion that divides the reticulated cell is bad, and dragged by the rotation of the roll, the cell shape tends to collapse.
According to a second aspect of the present invention, in the gravure roll for transferring a hot melt adhesive according to the first aspect, the depth of the cell is 0.05 mm to 0.2 mm.

  When the cell depth is less than 0.05 mm, the transfer amount of the hot melt adhesive is reduced and the sealing strength is lowered. When the cell depth exceeds 0.2 mm, the volume of the cell is increased. The transfer amount is large, the seal strength becomes unnecessarily large, and the cost increases.

  A third aspect of the present invention is the gravure roll for transferring a hot melt adhesive according to the first or second aspect, wherein the width of the bank portion between the cells is 0.01 mm to 0.10 mm.

  Even if the width of the bank portion is less than 0.01 mm or more than 0.10 mm, the amount of the hot melt adhesive applied to the laminate becomes non-uniform.

  The gravure roll for transferring a hot melt adhesive according to the present invention has a rhomboid or hexagonal shape of the mesh-like cells formed on the gravure roll, and one of the two opposite corners is on the rotation direction side of the roll In addition, since the other one corner is on the opposite side of the rotation direction of the roll and the angles of the two corners are both 120 ° to 160 °, when transferring the hot melt adhesive from the gravure roll to the laminate, Even if the viscosity is high, the yarn is not pulled in the rotation direction of the roll, so that various problems resulting from the yarn drawing phenomenon are eliminated.

It is an expansion | deployment partial top view of the gravure roll of this invention whose shape of a mesh-shaped cell is a rhombus. FIG. 2 is an enlarged cross-sectional view taken along line II-II in FIG. 1. It is an expansion | deployment partial top view of the gravure roll of this invention whose shape of a mesh-shaped cell is a hexagon. It is a partial expanded sectional view of the cover material in which the gravure roll of this invention was used and the heat sealing material layer was formed in the laminate material. It is the elements on larger scale of the cover material in which the conventional gravure roll was used and the heat sealing material layer was formed in the laminate material.

    FIG. 1 and FIG. 2 show that the shape of the mesh-like cell (2) formed on the gravure roll (1) for transferring the hot melt adhesive is a rhombus, and one of two opposing corners (A ) Is on the rotation direction side of the roll (1), the other corner (B) is on the opposite side of the rotation direction of the roll (1), and the two angles (A) and (B) are both 140 °. is there. The depth (C) of the cell (2) is 0.15 mm. The width of the bank portion (3) is 0.2 mm.

    Fig. 3 shows that the shape of the mesh cell (5) formed on the gravure roll (4) for transferring the hot melt adhesive is hexagonal, and one of the two opposite corners (D) is On the rotation direction side of the roll (4), another angle (E) is on the opposite side of the rotation direction of the roll (4), and the angles of the two angles (D) (E) are both 145 °. The depth of the cell (5) is 0.15 mm as in the case of FIG. The width of the bank portion (6) is 0.2 mm.

    Now, an aluminum foil (8) having a thickness of 30 μm is bonded to one side of a polyethylene terephthalate film (7) having a thickness of 12 μm with a polyurethane dry laminate adhesive to form a base material layer. Next, a polyethylene film (9) having a thickness of 20 μm is adhered to the surface of the aluminum foil (8) with the same adhesive as described above to form an intermediate resin layer, and the shape of the mesh cell (2) is formed thereon. Was used to transfer a hot melt adhesive having a viscosity of 150 ° C. and a viscosity of 6000 mPa · s to form a heat sealing material layer (10). A lid for a cup-shaped container for food was formed from the laminate composed of the base material layer, the intermediate resin layer and the heat sealing material layer (10) thus obtained. In the hot-melt adhesive after transfer, the portion corresponding to the mesh-like cell (2) becomes a smooth and loose crest portion (10a) as shown in FIG.

  However, when the hot-melt adhesive is transferred by a conventional gravure roll provided with square mesh-like cells to form the heat-sealing material layer (11), from the bank partitioning the mesh-like cells during the transfer. Since the cut is poor and the yarn is pulled by the rotation of the roll, the hot-melt adhesive after the transfer becomes a mountain-shaped portion (11a) having a sharply sharp upward shape as shown in FIG.

(1) (4) Gravure roll for transferring hot melt adhesive
(2) (5) Mesh cell
(3) (6) Bank part between cells
(A) (B) (D) (E) Opposite corners of the cell
(C) Cell depth

Claims (3)

  The shape of the mesh-like cell formed on the gravure roll is a rhombus or hexagon, and one of the two opposing corners is on the rotation direction side of the roll, and the other corner is on the rotation direction of the roll. A gravure roll for transferring a hot melt adhesive, which is on the opposite side and has two angles of 120 ° to 160 °.   The gravure roll for transferring a hot melt adhesive according to claim 1, wherein the cell has a depth of 0.05 mm to 0.2 mm.   The gravure roll for transferring a hot melt adhesive according to claim 1 or 2, wherein the width of the bank between the cells is 0.01 mm to 0.10 mm.

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