JPS6034834A - Preparation of polypropylene-laminate decorative sheet - Google Patents

Abstract

PURPOSE:To prevent the ''shear'' of a pattern in a finished state, by taking the shear amount into account inprinting the pattern. CONSTITUTION:A pattern is printed to be longer by 1.0-5.0% in the width direction and shorter by 1.0-5.0% in the direction of flow (the longitudinal direction) than finish measurements. Although excellent in the fitness for printing, an oriented PP film tends to shrink in the width direction in a laminating process, and particularly in laminating with a PP sheet by hot welding, since it is oriented, and therefore the pattern is printed to be longer beforehand by 1.0-5.0% than a finish measurement. In the direction of flow, to the contrary, the pattern tends to be stretched, since it is pulled in roll-up and other processes, and therefore it is printed to be shorter beforehand by 1.0-3.0%. The pattern may be lengthened or shortened within the above-stated ranges, though the degree of the lengthening or shortening cam be varied according to the degree of orientation, the thickness of the film, the temperature and speed in the laminating process and other factors.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polypropylene (hereinafter abbreviated as PP) laminated decorative sheets used for boxes, document cases, book covers, and various other uses. Thickness 20~40 than before
Printing on μ PP film with a thickness of 20~ on the printing surface
A PP laminated decorative sheet is known in which a 2oOμ PP film is laminated to protect the printed surface 1, and a 0.5 to 1.01!1 m thick PP sheet is laminated to the bottom surface to increase mechanical strength.

However, the printed PP film often shrinks during the subsequent lamination process, and the characters or patterns (hereinafter simply referred to as patterns) on the finished laminate often deviate from their predetermined positions. If the pattern is misaligned, it not only reduces the product value but also causes inconvenience during cutting and assembly. In the present invention, the pattern P in the finished state is printed in advance by planning for "misalignment" at the time of printing to prevent the pattern from shifting. On the other hand, it is 1.0 to 560% longer in the width direction, and the flow direction (longitudinal direction) K is 1.0 to 560% longer.
It prints 0 to 5.0% shorter.

To explain in more detail, stretched PP film has excellent printability, but since it is stretched, it is difficult to process the lamination process, especially for PP film.
When laminated by heat welding with sheets, shrinkage in the width direction1. Because it is easy, the pattern is finished in advance by 1.0 to 5.0% of the dimensions.
It should be printed for a long time. On the other hand, in the flow direction, the pattern tends to stretch due to tension during winding and other processes, so 1.
It is sufficient to print 0 to 3.0% shorter. The degree to which the pattern is lengthened or shortened may vary depending on the degree of stretching, the thickness of the film, the temperature and speed of the lamination process, and other factors, but may be within the above range.

On the other hand, when printing on an unstretched film, shrinkage occurs in the width direction, but the pattern tends to stretch in the machine direction for the same reason as mentioned above, and the extent of this shrinkage is greater than that of a stretched film. Therefore, the pattern may be printed 1.0 to 5.0% shorter in the machine direction.

Since the PP laminated decorative sheet finished in this manner has no pattern deviation, subsequent cutting and assembly processes can be carried out continuously.

In addition, in order to increase mechanical strength, the PP sheet laminated on the back side is colored transparent or semi-transparent, and a background pattern different from the original pattern is printed on the PP film that is printed in the same color as that coloring. This is even more preferable. Furthermore, in some cases, a pattern consisting only of a background pattern may be printed. The background pattern may be printed on the entire PP film in the same color except for the background pattern, or only the background pattern may be printed in the same color. By adding this background pattern, when light is transmitted through the PP laminated decorative sheet, the background pattern appears in a "watermark" state, thereby providing an aesthetic and distinguishing effect. In order to exhibit this "watermark" phenomenon, the finished PP laminated decorative sheet must be translucent. That is, if an object is placed between the viewing surface of the sheet and a light source such as sunlight or a fluorescent light (7'), the sheet may be translucent to the extent that the shape of the object can be recognized from the back surface.

In the present invention, any conventional method commonly used for PP films may be used to print on the PP film, but it is preferable to use a urethane-based or epoxy-based curable ink as the printing ink. Particularly when printing on a thick PP sheet, the printing ink hardens at room temperature, so no heating is required and distortion and deformation due to heat can be prevented. Further, the adhesive used when laminating the unstretched PP film to the printed PP film may be any adhesive commonly used for laminating PP films, but urethane-based or epoxy-based adhesives are preferred.

The unstretched film laminated on the printed PP film may be transparent, translucent, matte, or colored as long as it has a thickness of 20 to 200 μm, and in some cases, it may have a faint texture pattern when exposed to light. It may be translucent enough to be visible. Also 9
, 5~1.0fi thick reinforced extruded PP sheet is transparent,
It can be either translucent or opaque, but it can be either translucent or opaque.
It is only necessary to make it transparent or semi-transparent when adding a pattern.

When laminating an unstretched PP film on a printed PP film and then continuously heat-welding an extruded PP sheet for reinforcement,
0.5 to 1 O, OKq to the printed pp film laminate
It is preferable to apply a back tension of /crl. Application of back tension may cause the finished product to curl, but this curl can be corrected by annealing rolls (e.g. 40° C. to 100° C., 400 rolls). It is also preferable to emboss the back surface of the laminated surface of the reinforced PP sheet.

This embossing can be easily performed by performing it simultaneously with melt lamination.

The PP laminated decorative sheet according to the present invention has the effect of being extremely resistant to abrasion because it has a printed surface, and also has the effect of preventing discoloration and deterioration of printing ink. For example, if you use printed PP film as it is, you can directly apply reinforcing P to the back side.
If P sheets are thermally welded, the high temperatures often cause the ink to deteriorate and the color tone to change, but by laminating a PP film on the printing surface, such deterioration and discoloration can be prevented. A total of 7i of distortion and deformation of patterns during the manufacturing process
[Since the pattern is printed after inserting, it has the characteristic that there is almost no deviation of the pattern in the finished state.

Also, if you use unstretched film as the printing film,
This makes bending the product much easier. In other words, when using stretched film, it has excellent printability, but because it is stretched, there is little elongation during bending, and it may show peeling when cut. This can prevent such phenomena.

Furthermore, by printing a background pattern on the printed PP film and using a transparent or translucent reinforcing PP sheet of the same color as the background pattern, it is possible to give the product a "watermark" pattern.
This makes it extremely easy to identify similar products and products. Next, the present invention will be explained in detail by way of examples.

Example 1 A biaxially stretched polypropylene film with a thickness of 20 μm was printed in three colors using a gravure printing machine using urethane-based curable ink, and then an unstretched polypropylene film with a thickness of 70 μm was printed using a urethane-based curable adhesive. Polypropylene resin (adhered to protect the printed surface with a thickness of 0.71111)
Continuously welded and laminated at a resin temperature of 250°C), the printing dimensions at this time are width direction + 3.
6%, the back tension during melt lamination at -2.5 degrees in the flow direction was 5.3 Kg/cd.

The pattern on the resulting product was accurately applied to the planned dimensions and in the planned position, and subsequent secondary processing could be performed continuously. This effect was the same in the following examples, so a description thereof will be omitted.

Example 2゜ After two-color printing (gravure printing) using epoxy-based curable ink on a matte translucent film made of biaxially oriented polypropylene film with a thickness of 25 μm and roughened by sandblasting, urethane-based Thickness 5 using hardening adhesive
A film to which a 0μ blue colored unstretched polyprofilm was adhered and a film to which the unstretched polyprofilm was not adhered were continuously welded and laminated to a polypropylene resin (resin temperature: 245°C) adjusted to a thickness of 1 OB.

The printing size at this time is width direction + 2 compared to the finished size.
．． 0% and -1.5% in the machine direction, the back tension during lamination was 7.5 Ky/crl.

In the finished product, the printing ink was noticeably discolored in the product to which the unstretched polypropylene film was not glued, but the product to which it was glued was manufactured to the planned size without any discoloration.

Example 3゜White and black 2 on unstretched pale yellow polypropylene film with a thickness of 30μ
After color gravure printing, a pale yellow unstretched polypropylene film with a thickness of 150 μm was adhered using a urethane-based curable adhesive, and then a polypropylene resin with a thickness of 0.5 μm (
Continuous melt lamination at a resin temperature of 235℃ (pale yellow),
At the same time, a skin pattern was embossed on the back side.

The printing dimension at this time is 17% compared to the finished dimension, +4 in the width direction.
．． The back tension at 2 minutes was 9.5 Kg/i at 5 mm and -4.8% in the flow direction.

Since curling occurred on the molten laminate side of the finished product, the first roll was annealed at 70°C and the second roll at 50°C. In this case, the first roll is the roll with which the IT back surface is in contact, and the second roll is the roll with which the laminate surface is in contact. The resulting product was in accordance with the planned design, had no curls, and had no streaks that would cause peeling of the adhesive surface of the film due to insufficient elongation of the laminate film during the secondary process of creasing, making it a good product. was gotten.

Example 4 After printing on a biaxially stretched polypropylene film with a thickness of 40 μm using white urethane-based curable ink, a non-stretched polypropylene film with a thickness of 70 μm was bonded using an epoxy-based curable adhesive. The film was continuously melt-laminated onto a polypropylene resin having a thickness Q of 8 tim (resin temperature 250° C., colored white similar to the printing ink). The degree of invasion of the resin due to coloring at this time was such that the shadow of an object that came into contact with the resin could be recognized by sunlight.

Also, the printing dimensions are II] direction +3.8%, machine direction -1,
5 inches, and the back tension was 3Kg/ciI.

In the obtained product, it is very difficult to distinguish the printed part under normal conditions, but when viewed under sunlight, the product can be clearly distinguished. After printing using blue epoxy-based curable ink, a 35μ thick unstretched polypropylene film was glued with a urethane-based curable adhesive. , a blue coloring that is the same color as the printing ink) was continuously melt laminated. The degree of impingement due to coloring at this time was a translucent state through which fluorescent light was transmitted, and the printing dimensions were +4.0% in the width direction and -3.9 inches in the machine direction.

Pack tension at ') Mine) is 7.0Ky/cA
Met.

The resulting product had a "watermark" pattern as described above, making it difficult to distinguish colors under normal conditions.

Applicant: Sekisui Seiko Kogyo Co., Ltd. Agent Toshio Takigawa

Claims (4)

[Claims] (1) Print letters or patterns on the top surface of a polypropylene film with a thickness of 20 to 40 μm, laminate an unstretched polypropylene film with a thickness of 20 to 200 μm on the printed surface via an adhesive, and laminate a non-stretched polypropylene film with a thickness of 0.5 to 1.5 μm on the bottom surface with an adhesive. Off Polypropylene Sealing) When laminating continuously by hot welding, the characters or pattern to be printed should be printed at 1 in the width direction relative to the finished dimension.
．． A method for manufacturing a polypropylene laminated decorative sheet characterized by making it 0 to 5.0 inches longer and 1.0 to 5.0% shorter in the machine direction. (2) The polypropylene film to be printed is a stretched film, and the characters or patterns to be printed are 1.0 to 5.0% longer in the width direction than the finished dimensions, and if
1.0 to 3.0-short The method according to claim 1. (3) The polypropylene film to be printed is a non-stretched film, and the characters or patterns to be printed are 1.0 to 5.0 inches longer in the width direction and #'1 in the machine direction than the finished dimensions.
The manufacturing method according to claim 1, which is 1.0 to 5.0% shorter. (4) Thickness 0.5 to 1.010 laminated by heat welding
The manufacturing method according to claim 1, wherein the first polypropylene sheet is colored transparent or translucent, and the polypropylene film to be printed has a background pattern in the same color as the colored color.