JPH04197775A - Manufacture of film with printing and embossing - Google Patents

Abstract

PURPOSE:To enable printing and embossing process in a continuous integrated processing manner by printing and them embossing polyethylene cross-linked, elongated film which is composed of high-density polyethylene and has a degree of cross-linkage decreasing toward the inner side in a film thickness direction, at normal temperature. CONSTITUTION:Polyethylene cross-linked, elongated film 1A is allowed to run through an area between the first plate cylinder 2 and a pressure cylinder 3 of a gravure press, then the first color is printed and the printed film is caused to pass through the first dryer 4 for drying. After that, the film 1A is allowed to pass through an area between the second plate cylinder 2 and the pressure cylinder 3, then the second color is printed, and the printed film is dried using the second dryer 5. In addition, the film is caused to run through an area between the third plate cylinder 2 and the pressure cylinder 3, then the third color is printed and the printed film is caused to pass through the third dryer for drying. In these process steps, tri-color, multi-color printed polyethylene cross-linked, elongated film 1B is obtained. This film 1B is caused to pass through an area between an embossing roll 7 and a coating roll 8 at normal temperature without heating. The embossed film 1C is taken up by a winding roll 9 into a multi-color embossed film.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for printing/embossing a plastic film that is excellent in three-dimensional appearance, luxury and cosmetic properties, and in particular, a method for printing and embossing in one step. The present invention relates to a method of manufacturing a printed/embossed film.

[Conventional technology] Conventionally, plastic films printed in multiple colors and embossed on top have been used as interior materials such as wallpaper because of their three-dimensional and luxurious appearance and excellent cosmetic properties. There is.

For such printed/embossed films, it is customary to heat and emboss the film, which has already undergone a printing process, in a separate embossing process.

However, since it is not economical to perform this printing/embossing in two steps, it has been considered to perform printing/embossing in an integrated process in-line.

However, when the printed film is subsequently heated and embossed, especially when performing multicolor printing, the pitch of the multicolor printing and the embossing may be misaligned due to the film's expansion due to heat and contraction due to cooling. However, there was a problem in that it was difficult to match the pitch, and a clear printed film in which the printed and embossed patterns matched could not be obtained.

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems, performs printing and embossing on a plastic film in a continuous, integrated process, so that the printed and embossed patterns match, The purpose of the present invention is to provide a method for obtaining a printing film with excellent three-dimensional effect and cosmetic properties.

[Means for Solving the Problems] The present invention provides that the objects of the present invention can be achieved by using a polyethylene crosslinked stretched film having a special crosslinked structure in the thickness direction of the film as a plastic film to be printed. Based on this heading, the present invention has been completed.

That is, the present invention is a printing process characterized in that a polyethylene crosslinked stretched film made of high-density polyethylene and in which the degree of crosslinking decreases inward in the thickness direction of the film is printed, and then embossed at room temperature. /
The gist is a method for manufacturing embossed film.

Next, the method for producing a printed/embossed film of the present invention will be explained with reference to the drawings showing one embodiment thereof.

As shown in FIGS. 1 and 2, the polyethylene crosslinked stretched film IA of the present invention is passed between the first plate cylinder 2 and the impression cylinder 3 of a gravure printing machine, -color is printed, and the 1 dryer 4, and then the second dryer 4.
The two-color printing sheet 1 is passed between the plate cylinder 2 and the impression cylinder 3.
It is dried in the second dryer 5, and then passed between the third plate cylinder 2 and impression cylinder 3 to print two-color printing, and then passed through the third dryer 6 and dried to print three-color printing. A multicolor printed ethylene crosslinked stretched film IB. This multicolored film IB is then passed between the embossing roll 7 and the rubber-coated roll 8 without heating (at room temperature).

In addition, when embossing, the pitch of the multicolor printing point and the embossing mark are matched in advance.

The embossed film 1C is wound onto a take-up roll 9 to become a multicolor embossed film.

The polyethylene crosslinked stretched film IA in the present invention is
The film is made of high-density polyethylene, and the degree of crosslinking decreases toward the inside in the thickness direction of the film, or uncrosslinked portions are formed.

The density of high density polyethylene in the present invention is 0.93
5 g/cm' or more is preferable, more preferably 0.95
It is 0g/am3 or more. Density is 0.935 g/a
If it is less than m3, the stiffness of the stretched film is insufficient.

The melt index (measured according to JIS K 6760, measured at a temperature of 190° C. and a load of 2.16 kg, hereinafter referred to as MI) is preferably in the range of 05 to 20 g/10 minutes from the viewpoint of film formability.

In addition, High Road Melt Index (HLMI)/M
From the viewpoint of transparency, I is preferably 50 or less, and more preferably 25 to 45.

Although homopolymers or copolymers of ethylene can be used,
A mixture may be used as long as it is within the above range.

In the present invention, linear low density polyethylene (LLDPE) or (and) petroleum resin is added to high density polyethylene by 15%.
A resin composition containing up to % by weight may also be used.
``LLDPE is preferable in order to give the film a soft feel.

The crosslinked stretched polyethylene film IA used in the present invention has a reduced degree of crosslinking or has uncrosslinked portions on the inside in the thickness direction of the film, for example,
By irradiating an electron beam from both sides of a polyethylene resin base sheet, for example, a sheet with a specific crosslinking degree, such as both surface layers being crosslinked but the intermediate layer having a low degree of crosslinking (for example, not crosslinked), can be produced. It can be obtained by biaxially stretching by a tenter method, or by stretching or rolling a sheet between rolls in the machine direction (MD) and then stretching in the transverse direction (TD) to form a film.

The degree of crosslinking mentioned above can be expressed in terms of gel fraction.

The gel fraction is the ratio of the insoluble portion of a sample extracted with boiling P-xylene.

The gel fraction of the crosslinked layer on both sides of the film in the thickness direction is 20 to 7.
0 wt%, gel fraction of uncrosslinked or low crosslinked intermediate layer is 0
It is preferably 5 wt%.

Further, the composition ratio of the uncrosslinked or low crosslinked intermediate layer to the crosslinked layers on both sides is preferably such that the intermediate layer/both side crosslinked layers = 1 = 01 to 10.

Further, the stretching is performed by stretching three times or more in at least one direction from a temperature above the softening point of polyethylene to a temperature below the melting point.

In the present invention, it is preferable for the embossability of the film that the stretching ratio in one direction is higher than the stretching ratio in the other direction. A biaxially stretched film with an area F@skewer of 7 times or more is preferable, which is obtained by unbalance stretching at a stretch ratio of 20 times or less in one direction and a stretch ratio of 5 times or more in the other direction. For example, 1.
A biaxially stretched film of 2 (M'D) x7 to 8 (TD) times is recommended.

The thickness of the polyethylene crosslinked stretched film in the present invention is appropriately selected depending on its use, but is usually 10 to 100 mm.
A material of the order of μ is used.

Regarding the manufacturing method and other preferable conditions for the polyethylene crosslinked stretched film, see, for example, JP-A-59-1743.
The matters disclosed in Publication No. 22 and Publication No. 61-74819 are applicable.

The means of printing in the present invention is not limited to gravure printing,
Various methods of printing on plastic can be applied. Examples include flexo printing, silk screen printing, offset printing, and the like.

In the embossing process of the present invention, by pressing with a press stamper having an uneven shape of the hologram master, a replica white transmitted light reproduced surface unevenness (relief) phase type is applied to the polyethylene crosslinked stretched film for multicolor printing. You can get a rainbow hologram.

[Example] Next, examples of the present invention will be shown.

In addition, each physical property in an Example was measured by the test method shown below.

(11MI: JIS K 6760 (2) Gel fraction: ASTM D 2765 A method compliant (3) Haze: JIS K 6714 Example 1
6 Density is 0.953g/cm3, MI is 07, HLMI
Polyethylene with a temperature of 27 is heated to T at 250°C using an extruder.
- A sheet was formed by extrusion from a die and cooling. When the electron beam was irradiated at 20 Mrad from both sides of this sheet, the crosslinked layer: uncrosslinked layer: crosslinked layer = 1:0.5:1, and the gel fraction was on the irradiated side and the lowest: irradiated side = 50:0: Fifty raw sheets (700 microns thick) were obtained. Temperature 11 of this sheet
Stretching was performed at 0° C. at a stretching ratio of 1.2 times in the MD direction and 7.5 times in the TD direction to obtain a stretched film (80 microns thick). The haze value was 40.

After corona discharge treatment, a three-color floral pattern is printed on this crosslinked stretched film using the gravure printing machine described above, and then the multicolored floral pattern is printed at room temperature (23°C) without heating. The corresponding embossing process was carried out. This floral print and embossed pattern had no pitch deviation, and a printed film with excellent cosmetic properties and three-dimensional spacing was obtained.

For comparison, similar printing and embossing were performed on a polyvinyl chloride film (80 micron thick, PVC), but although multicolor printing was obtained, an embossed pattern could not be imparted.

[Effects of the Invention] The polyethylene crosslinked stretched film of the present invention can be provided with an embossed pattern at room temperature without heating, so the embossed pattern can be created in one step without causing pitch deviation on the multicolor printing film. (inline).

Therefore, it is possible to efficiently produce a printing film that is excellent in three-dimensional appearance, luxury appearance, and cosmetic appearance, and work efficiency is greatly improved. Furthermore, since embossing can be performed at room temperature, there is no pitch deviation between printing and embossing, and it is easy to apply various types of patterns to multicolor printing films.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example process of the present invention, and FIG. 2 is a diagram of the principle of gravure printing. IA... Polyethylene crosslinked stretched film 2... Plate cylinder 3... Impression cylinder 4.5.6... Dryer 7... Embossing roll 8... Rubber coated roll 9... Winding roll patent Applicant Tonen Petrochemical Co., Ltd. Representative Patent Attorney Yoshihiro Sato Figure 1 2t! 1

Claims (1)

[Claims] 1. A printed/embossed film made of high-density polyethylene, which is characterized by printing on a cross-linked stretched polyethylene film in which the degree of cross-linking decreases inward in the thickness direction of the film, followed by embossing at room temperature. manufacturing method.