JPH05237949A - Polyolefin foam and printing method thereof - Google Patents

Abstract

PURPOSE:To prevent a printing layer from peeling and transferring without corona treatment by slicing a polyolefin foam having closed cell such that the closed cell is cut off and forming the printing layer on the sliced face such that the printing layer infiltrates into the closed cell. CONSTITUTION:A cross-linked polyethylene foaming sheet 1, for example, having closed cell with average diameter of 0.05-1.0mm is sliced in parallel with the surface at the center in the direction of thickness. At this time, the closed cell is cut off so as to be a cut closed cell 13 having an inner wall face 131. Printing is performed on a sliced face 12 by a printing ink 2 containing a solvent. It is heated immediately after the printing so as to evaporate the solvent rapidly and the membrane is cured so as to form a printing layer 14. Polyamide resin is included in the ink so as to improve the waterproof property of the printing layer 14. Thus, the printing ink enters the inside of the cut closed cell 13, so that the printing layer 14 is formed on the inner wall face 131 and peeling and transferring can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin foam having a sliced surface printed so as to cut closed cells, and a printing method thereof.

[0002]

2. Description of the Related Art Foams made of olefinic resin have various fine characteristics such as uniform and fine closed cells, light weight, excellent heat insulating property, excellent buffering property and withstanding load capacity. Therefore, it has been used as an excellent packaging material and heat insulating material. And such a polyolefin-based foam,
Usually, on a smooth surface with its thin skin, marks,
By printing letters, decorative patterns, etc., the source value and quality are guaranteed, the usage method is clearly indicated to ensure proper use of the product, and the decorativeness is enhanced to increase added value. It is used as a product. However, since the polyolefin-based foam has poor adhesiveness, the print layer is easily peeled off or transferred due to the slight adhesive force applied to the smooth print layer on the surface.

However, for example, a smooth surface having a thin skin portion is subjected to surface treatment such as corona treatment, and printing is performed thereon to enhance the adhesion of the printed layer to the surface of the polyolefin foam. Is being done.

[0004]

However, if corona treatment is performed on all the surfaces that need to be printed, the number of treatment steps is increased, and capital investment is required, resulting in a decrease in productivity and an increase in cost. There is a problem that or,
Even if you print on a smooth surface, countless holes (about 1φ pinholes) are likely to occur on the surface of the foam during corona treatment, and if you print on it, there will be pinholes in the printed layer, It is not always necessary to print with a beautiful appearance.

The present invention solves the problems of the conventional methods as described above, and prints a polyolefin-based foam which is printed without peeling or transfer of the printing layer without corona treatment. And a printing method thereof.

[0006]

A polyolefin-based foam of the present invention is provided with a printing layer on a slice surface sliced so as to cut the closed cells of the polyolefin-based foam having closed cells, and the printing layer is The closed air bubbles that have been cut into the inside of the closed air bubbles are in close contact with the inner wall surface thereof.

The method for printing a polyolefin-based foam of the present invention is a printing ink containing a solvent, which is obtained by slicing a polyolefin-based foam having closed cells so as to cut the closed cells. Is a method in which printing is performed so as to enter the inside of the cut closed bubbles, and then the solvent in the printing ink is evaporated to bring the printing layer into close contact with the inner wall surface of the closed bubbles.

In the present invention, an olefin-based foam having closed cells, which is a foam having poor printing characteristics, is used. Specific examples thereof include foams made of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, and the like.

In the present invention, as the olefin resin foam, those having closed cells and having a spherical diameter of 0.05 to 1.0 mm are preferably used. If the sphere diameter is less than 0.05 mm, it tends to be difficult for the printed layer to enter the inside of the cut independent bubbles and enter the inner wall surface of the cut independent bubbles to be closely attached,
On the other hand, when it exceeds 1.0 mm, even if the printing layer enters the inside of the cut closed cells and adheres to the inner wall surface thereof, the anchoring effect is small and peeling or transfer tends to occur. There is.

In the present invention, an ink containing a solvent is used as the printing ink. What is ink containing solvent?
It is a type that contains a color material, a resin, and a solvent and rapidly evaporates the solvent by heating immediately after printing to solidify the film. By using the ink containing the solvent, even if the printing is performed so that it penetrates even into the inside of the cut closed bubbles, the solvent in the printing ink is easily evaporated in a short time in the subsequent drying step. It can be dried. In addition, since the printed layer of the printed polyolefin foam has excellent water resistance, it can be suitably used in applications where it is exposed to moisture or water.

As the color material, commonly used pigments such as organic pigments, inorganic pigments and carbon black, and special color materials such as fluorescent dyes are used.

As the resin, for example, polyamide resin,
Synthetic resins such as rosin-modified phenolic resin, vinyl chloride-vinyl acetate copolymer, rubber derivatives, and natural resins such as rosin are used.

As the solvent, a solvent that does not dissolve the polyolefin foam is used. Ester solvents, alcohol solvents, ketone solvents, aromatic solvents and the like are used. Specific examples thereof include ester-based solvents such as methyl acetate and ethyl acetate, alcohol-based solvents such as methanol-based solvents such as methanol and ethanol, and ketone-based solvents. Examples of the solvent include acetone and methyl ethyl ketone, and examples of the aromatic solvent include toluene. The amount of solvent added to the printing ink is
It is necessary to have a viscosity that is suitable for being able to enter the inner wall surface of the cut closed cells and to form a coating of the printing layer after drying. Depending on the resin, in the printing ink,
40 to 85 parts by weight is preferable.

The viscosity of the printing ink is 50 to 1
A range of 10,000 poise is preferred. When it is less than 50 poise, when the printing ink is applied and dried, the strength of the coating as the printing layer is weak, and the printing layer tends to peel off or transfer, and conversely 10,000 poise. If it exceeds, it tends to be difficult to let the cut closed bubbles enter the inner wall surface.

In the present invention, as the printing method, gravure printing method, letterpress printing, screen printing, offset printing and the like can be preferably adopted, and the gravure printing method is particularly preferably adopted.

The printed polyolefin foam obtained according to the present invention may be used, for example, in sports,
Packaging materials in the fields of miscellaneous goods, heat insulation, construction civil engineering, vehicles
Examples include heat insulating materials and condensation preventing materials. And, for example,
When used as a packaging material, the polyolefin foam is packaged with the surface having the smooth thin skin layer facing the packaging side and the printed slice surface facing the outside. As a result, the highly sliced surface absorbs the impact from the outside to protect the packaged contents, and the sliced surface is printed to guarantee the origin and guarantee the quality, and clearly indicate the usage method. Appropriate use of the product and enhancement of decorativeness can be achieved. When used as a plate as a dew condensation prevention material, a polyolefin foam is applied to the back surface of the roofing material with the surface having a smooth thin skin layer facing the printed slice surface facing the indoor side. Attach and use. This allows the sliced surface, which is highly hygroscopic, to absorb indoor moisture and prevent dew condensation, and the printing on the sliced surface can guarantee the origin and quality of the product, or enhance decorativeness. it can.

[0017]

In the polyolefin foam of the present invention, a printing layer is provided on the sliced surface sliced so as to cut the closed cells of the polyolefin foam having closed cells,
Since the printed layer penetrates into the inside of the cut closed air bubbles and adheres to the inner wall surface of the cut air bubble, the part of the printed layer that penetrates into the inner surface of the closed air bubble and adheres to the inner wall surface provides an anchor effect. When the pressure-sensitive adhesive layer comes into contact with the surface of the printing layer, the printing layer does not peel off or transfer from the polyolefin foam.

In the method for printing a polyolefin foam of the present invention, a polyolefin foam having closed cells is sliced so as to cut the closed cells, and the cut slice surface of the closed cells contains a printing ink containing a solvent. Printing is performed so that it enters the inside of the cut closed bubbles, and then the solvent in the printing ink is evaporated and the printed layer is brought into close contact with the inner wall surface of the closed bubbles. It is possible to manufacture a polyolefin-based foam that penetrates into the inside of the and firmly adheres to its inner wall surface.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be described below with reference to the accompanying drawings. 1 to 5 are explanatory views sequentially showing steps of one embodiment of the invention. In FIG. 1, reference numeral 1 is a polyolefin-based foam having closed cells and having closed cells on its surface. As shown in FIG. 2, the polyolefin-based foam 1 is sliced at the center in the thickness direction so that the closed cells are cut along a plane parallel to the surface. As a result, as shown in FIG. 3, the inner wall surface 13 of the cut independent bubbles 13 is exposed on the slice surface 12. As shown in FIG. 4, printing is performed on the slice surface 12 using the printing ink 2 containing a solvent. In this case, since the printing ink contains a solvent and has a low viscosity, the printing ink enters the inside of the cut closed air bubbles 13 exposed on the slice surface 12 and contacts the inner wall surface thereof. When dried in this state, the solvent in the printing ink evaporates, and as shown in FIG. 5, the printing layer 14 is cut on the sliced surface 12 of the polyolefin foam 1, and the inner wall surface 131 of the closed closed cells 13 is cut. As a result, a polyolefin-based foam provided so as to penetrate into the cut end surface and to be in close contact therewith is obtained.

Example A polyolefin foam having a thickness of 8 mm and a density of 0.
A cross-linked polyethylene foam sheet having an average sphere diameter of closed cells of 0,25 g / cc and a diameter of 0.3 mm is used, and the cross-linked polyethylene foam sheet is sliced along a plane parallel to the surface at the center in the thickness direction. Chrome plating specification, plate depth 34μm, screen line 1
Adopting the method of printing with 40 gravure rolls, the printing ink is gravure ink for polyolefin [Osaka Printing Ink Mfg. Co., Ltd .: trade name "POC weatherproof ink",
Pigment 8.8 parts by weight, polyamide resin 18.0 parts by weight,
5.0 parts by weight of tackifying resin, 2.0 parts by weight of waxes,
7.0 parts by weight of ester solvent, alcohol solvent 19.
0 parts by weight, aromatic solvent 38.7 parts by weight] 100 parts by weight, diluted with 30 parts by weight of toluene, using an ink,
The cross-linked polyethylene foam sheet was printed according to the steps of FIGS. The printing performance of this crosslinked polyethylene foam sheet was evaluated for the adhesion performance of printing ink as follows. The results are shown in Table 1.

Transferable cross-linked polyethylene foam sheet to acrylic coated steel sheet is placed in parallel with the printed surface facing upward, and the acrylic coated steel sheet is placed on the printed surface,
A load of 6.5 g / cm ² was applied from above, and after leaving in an atmosphere of 40 ° C. for 24 hours and in an atmosphere of 60 ° C. for 24 hours, the acrylic coated steel sheet was peeled off, and the surface area of the printing ink transferred was%. Was visually measured to determine the transferability.

Transferable cross-linked polyethylene foam sheet to cellophane tape is placed in parallel with the printing surface facing upward, and cellophane tape (Sekisui Chemical Co., Ltd .: trade name "Sekisui Cello Tape") is glued on the printing surface. The layer surface was placed facing the printing surface, a roller having a load of 1 kg / 50 mm was reciprocated once, and then the cellophane tape was peeled off to observe the transferability of the printing ink to the adhesive layer of the cellophane tape.

Comparative Example 1 A crosslinked polyethylene foam sheet was printed in the same manner as in Example 1 except that the thin skin surface of the crosslinked polyethylene foam sheet was printed without corona treatment. The printing surface of this crosslinked polyethylene foam sheet was evaluated for printing ink adhesion performance as follows. The results are shown in Table 1.

Comparative Example 2 A crosslinked polyethylene foam sheet was printed in the same manner as in Example 1 except that the thin skin surface of the crosslinked polyethylene foam sheet was subjected to corona treatment and then printing. The printing surface of this crosslinked polyethylene foam sheet was evaluated for printing ink adhesion performance as follows. The results are shown in Table 1.

[0025]

[Table 1]

[0026]

Since the method for producing a polyolefin foam of the present invention is constructed as described above, the printed layer is not peeled off or transferred from the polyolefin foam.

Since the method for printing a polyolefin-based foam of the present invention is configured as described above, the polyolefin-based foam that has penetrated into the inside of the closed cells in which the printing layer has been cut and is firmly adhered to the inner wall surface of the closed foam. The body can be manufactured.

[0028]

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a polyolefin foam having closed cells.

FIG. 2 is a vertical cross-sectional view showing a state in which the foam shown in FIG. 1 is sliced along a plane parallel to the surface and a plane parallel to the surface.

FIG. 3 is a vertical cross-sectional view showing a state in which a sliced surface obtained by cutting closed cells is exposed.

FIG. 4 is a vertical cross-sectional view showing a state in which a printing ink containing a solvent is poured into the cut independent bubbles.

FIG. 5 is a vertical cross-sectional view showing a state in which a printing layer is provided on the inner wall surface of the cut closed cells and the end surface of the cut surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyolefin-based foam 2 Printing ink 11 Thin skin 12 Slice surface 13 Cut closed cells 14 Printing layer 131 Inner wall surface

Claims (2)

[Claims] 1. A printing layer is provided on a sliced surface of a polyolefin-based foam having closed cells, which is sliced so as to cut the closed cells, and the printing layer penetrates into the inside of the cut closed cells. A polyolefin foam characterized in that it is adhered to the inner wall surface. 2. A polyolefin foam having closed cells is sliced so as to cut the closed cells, and the cut surface of the closed cells is cut with a printing ink containing a solvent to the inside of the cut closed cells. A method for printing a polyolefin foam characterized in that printing is carried out as if it enters, and then the solvent in the printing ink is evaporated to bring the printing layer into close contact with the inner wall surface of the closed cells.