JPH0890736A - Decorative sheet manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] Uses materials other than vinyl chloride resin, has properties that exceed those of vinyl chloride resin sheets, has appropriate flexibility suitable for post-processing, and has excellent emboss reproducibility. Excellent,
Provided is a method for manufacturing a decorative sheet which is durable and has excellent design. [Structure] A base sheet 9 made of an olefinic resin having an arbitrary printed pattern and an embossed sheet 8 obtained by extruding a molten olefinic transparent thermoplastic resin onto an embossed cooling roll 14 are laminated. At this time, after the corona treatment 17 is applied to the back surface of the embossed sheet, the adhesive is applied in an amount of 5 to 15 g / m ² .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a printed sheet that is printed and embossed, and is used as a decorative sheet by bonding it to the surface of wooden boards, inorganic boards, metal plates, etc. with an adhesive. The present invention relates to a method for manufacturing a decorative sheet used.

[0002]

2. Description of the Related Art Conventionally, a vinyl chloride resin sheet has been the most popular as a decorative sheet used for the above purposes. However, vinyl chloride resin is said to cause hydrogen chloride gas generation, acid rain, and dioxin generation during incineration, and in recent years, decorative sheets that do not use vinyl chloride resin sheets have been demanded from the viewpoint of environmental problems. . However, for resin sheets other than vinyl chloride resin, the vinyl chloride resin sheet has the appropriate flexibility, abrasion resistance, chemical resistance,
None of them satisfy the well-balanced properties such as stain resistance and weather resistance.

Further, according to the manufacturing method, in the conventional vinyl chloride resin decorative sheet, the emboss imparted for mechanically embossing by heat and pressure reproduces only about 70% of the embossing plate, and the embossing also occurs. It has a drawback that it disappears when left in an atmosphere of about 100 ° C. for a long time.

Therefore, it has been considered to use a thermoplastic resin as a resin replacing the vinyl chloride resin. However, when bonding the base sheet and the embossed transparent embossed sheet, a method using heat and pressure or applying an adhesive to the base sheet,
The Neelam method that attaches embossed sheets after drying is
As disclosed in Japanese Patent Application Laid-Open No. 6-155692, when an adhesive is applied to a base material sheet, peeling due to lack of bonding strength, that is, durability, and air remaining on the bonding surface, designability is improved. There was a problem that it was significantly damaged.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the problem is to use a vinyl chloride resin sheet using a material other than vinyl chloride resin. In order to provide a method for manufacturing a decorative sheet having properties that exceed the characteristics of, the product has appropriate flexibility, which is particularly suitable for post-processability, has excellent emboss reproducibility, and has durability and a design. The present invention relates to a method for producing a decorative sheet having excellent properties.

[0006]

In order to solve this problem, the present invention is embossed with a base sheet made of an olefinic resin having an arbitrary printed pattern and a molten olefinic transparent thermoplastic resin. When bonding the embossed sheet obtained by extrusion onto a cooling roll, the back surface of the embossed sheet is subjected to corona treatment, and then an adhesive agent
Provided is a method for producing a decorative sheet, which comprises applying 15 g / m ² .

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an example of a cross-sectional view of a decorative sheet according to the present invention. FIG. 2 shows an example of a sectional view of the embossed sheet according to the present invention. FIG. 3 shows an example of the manufacturing process of the decorative sheet according to the present invention. FIG. 4 shows an example of a conventional manufacturing process for a decorative sheet. The molten olefin-based transparent thermoplastic resin 4 is extruded between the embossed cooling roll 14 and the pressure roll 15, and is cooled and solidified and embossed simultaneously to obtain the transparent embossed sheet 8. The back surface of the embossed sheet is subjected to corona treatment by the corona treatment device 17, the adhesive is applied to the corona treatment surface by the adhesive application device 18, the solvent is removed by the drying device 19, and the product is dried. The base sheet 9 made of an olefin resin on which the pattern 2 is printed and the hot-press roll 20 are stuck together,
The embossed decorative sheet 10 is obtained. In some cases, it is possible to improve the design by corona-treating the surface of the obtained embossed decorative sheet, embedding the ink 6 in the embossing, and then providing the topcoat layer 7 on the outermost surface.

Each of the embossing roll 14 and the pressure roll 15 has a cooling mechanism inside, and has the effect of lowering the temperature of the molten resin and solidifying it. Usually, the embossing roll is made of metal and the pressure roll is made of rubber on the surface. As for the pressure roll, a metal backup roll 16 having a cooling mechanism inside is generally attached to assist the pressure and cooling.

On the other hand, FIG. 4 shows an example of a conventional manufacturing process of a decorative sheet, which is called the Neelham system which is widely used in the field of packaging materials. This method has a problem in that air remains on the bonding surface of the base material sheet and the embossed sheet, which significantly impairs the design. As a result of intensive studies to elucidate the cause of this, as shown in FIG. 2, strike-through of the embossed pattern on the back surface of the embossed sheet 11
It was discovered that air remained and air remained here. Furthermore, they have found that the above problem can be solved by applying an adhesive agent in an amount of 5 to 15 g / m ² on the back surface of the embossed sheet in which the strike-through of the embossed pattern has occurred, and arrived at the present invention.

As the olefin type transparent thermoplastic resin used in the present invention, any of polypropylene homopolymer, lantam polymer, block polymer and low density polyethylene, α-olefin, ethylene-propylene copolymer rubber as a soft component can be used. Alternatively, a resin formed by simply mixing the mixture in an amount of 5 to 30% by weight and adding the resin can be used.

The type of polypropylene polymer is
If the obtained sheet is required to have heat resistance, hardness, etc., a homopolymer is used. If impact resistance is required, a block polymer is used. If impact resistance, low temperature processability, and transparency are required, a random polymer is appropriately used. Just select it. However,
Random polymerization type polypropylene can be said to be optimal because the low temperature processability that is characteristic of vinyl chloride resin sheets is emphasized.

When the amount of the soft component added is 5% by weight or less, there is no effect on the low temperature processability, and when it is 30% by weight or more, the elasticity of the obtained sheet is too large. The soft component to be added is simply mixed, but this not only simplifies the process, but also reduces the transparency when cross-linking the two, or the interface of the soft component that cross-links in polypropylene and takes a domain structure. This is because there is an inconvenience such as a whitening phenomenon caused by an impact on the.

It is desirable to use, as the base material sheet 1 in the present invention, one made of a polyolefin resin excluding the soft component in the extruded resin because the ink adhesion is improved.

Further, in order to obtain a concealing property when it is used as a decorative sheet, it is desirable that this base sheet be arbitrarily colored with an inorganic pigment or the like. Further, an antioxidant is appropriately added when the sheet is extruded and an antioxidant is added to prevent thermal oxidation of the obtained product, and a light stabilizer is appropriately added to prevent deterioration of the obtained product by ultraviolet rays. The types and amounts of these additives are not specified, and those generally used for olefins may be added. From this effect, it is optimal to combine a phenol type antioxidant and a hindered amine type light stabilizer. However,
It is necessary to note that the hindered amine-based additive reacts with some phenol-based additives by light to form a quinoid bond and causes a so-called pinking phenomenon.

Further, the ink used for the arbitrary pattern 2 is not particularly specified as long as it adheres well to the base sheet, but urethane type ink is most suitable because of the cohesive force of the ink itself and versatility. is there. In addition, a chlorinated olefin ink can be used because it adheres to an olefin sheet, but it is out of the scope of the present invention in that chlorine is disliked.

For the molten olefin type transparent thermoplastic resin 4 to be embossed, a similar resin type may be selected for the same reason as the base sheet. In particular, since it is a sheet to be embossed, transparency is required. Therefore, in some cases, it is possible to add a nucleating agent to polypropylene to increase transparency. As the nucleating agent, known substances such as silica and stearic acid are used.

Since the embossed sheet 8 on the surface is transparent, in order to prevent ultraviolet rays from being applied to the base sheet, the adhesive and the ink, the molten resin 4 contains not only an antioxidant and a light stabilizer but also a benzotriazole type. An ultraviolet absorber represented by is added. Also, since it is a transparent resin layer, unlike the base sheet, no coloring pigment is added.

The extruded molten resin 4 is cooled and solidified and embossed at the same time by the embossed cooling roll 14. However, in the heating doubling embossing conventionally performed on a vinyl chloride decorative sheet. Since it is in a state where molten resin is put in the mold rather than mechanically embossing like this, even very fine embossing such as used for holograms can be entered without problems, and embossing after embossing It has good heat resistance.

Here, in order to emboss the molten resin 4, the molten resin 4 is pressed against the embossed cooling roll 14 by the pressure roll 15. In a conventional casting method such as an air knife method or an air chamber method, which is used for molding polypropylene, the force for pressing the resin against the emboss is weak, and the embossing becomes loose.

The back surface of the embossed sheet 8 obtained as described above is subjected to corona treatment by the corona treatment device 17. The corona treatment device may be a general one and is not particularly limited. The degree of corona treatment depends on the surface condition of the extruded embossed sheet, but the surface tension of the sheet surface is 40 to 55 dyne / cm.
Is desirable.

Next, the adhesive 3 is uniformly applied to the corona-treated surface. Adhesive 3 is not particularly specified as long as it is commercially available for polyolefin, and urethane-based, polyester-based, water-based acrylic emulsion-based, etc. can be used. It can be said to be optimal. A general coating method may be used as the adhesive coating method and is not particularly limited, but a comma coater is preferable because the coating amount is 5 to 15 g / m ² . If the amount of the adhesive applied is too small, air remains on the bonding surface as described above, and if it is too large, whitening occurs when the sheet is folded. Further, the drying device 19 may be a general drying device and is not particularly limited.

Finally, the embossed sheet 8 and the base material sheet 9 are attached to each other by a hot press roll 20 to obtain a decorative sheet 10 of the present invention. It is also possible to embed the conduit ink 6 in the embossed portion 5 and further provide the top coat layer 7 in order to impart a higher design property.

[0023]

As described above, by using an olefin resin as the base sheet and the transparent thermoplastic resin for melt extrusion as in the present invention, printability, heat resistance, weather resistance and flexibility superior to those of vinyl chloride sheets can be obtained. It has become possible to add the like. In particular, by appropriately selecting polypropylene and a soft component for the embossed sheet 8, it becomes possible to obtain a sheet having excellent post-processability at low temperature.

Further, since the resin is melt-extruded and held in an embossed cooling roll at the same time, there is no fear of returning to emboss due to heat during post-processing, and fine embossing such as used for holograms can be imparted. It has become possible.

Further, by coating the back surface of the embossed sheet with an adhesive agent in an amount of 5 to 15 g / m ² , peeling due to insufficient bonding strength, that is, durability, and air remaining on the bonding surface significantly impair the design. The problem like that disappeared.

[0026]

【Example】

<Example 1> As a base material sheet, 6% by weight of an inorganic pigment, 0.2% by weight of a phenolic antioxidant and 0.3% of a hindered amine light stabilizer were used in a randomly polymerized polypropylene.
Wt% and a resin containing 0.2% by weight of an antiblocking agent are melt-extruded, corona-treated, and then gravure printing is used for the pattern ink (Toyo Ink Mfg. Co., Ltd .: Lamister) Was used to give a wood grain pattern.

Separately from this, 15% by weight of low density polyethylene, 0.2% by weight of a phenolic antioxidant, 0.3% by weight of a hindered amine light stabilizer and 0.3% by weight of a benzotriazole ultraviolet absorber are added to randomly polymerized polypropylene. A resin to which 0.5% by weight and 0.2% by weight of an antiblocking agent were added was melt-extruded from a T-die between a cooling roll and a pressure roll having conduit embossing to obtain an embossed sheet.

A corona treatment was applied to the back surface of this embossed sheet, and an adhesive (AD-806 manufactured by Toyo Morton Co., Ltd.) was applied to the corona-treated surface with a comma coater at 10 g /
m ^{2 was} applied and dried.

The embossed sheet thus obtained and the substrate sheet were rolled at a temperature of 80 ° C. and a linear pressure of 5 kgf /
A hot pressing roll having a diameter of 0.1 cm was used to obtain a decorative sheet.

<Comparative Example 1> A sheet in which ink (Toyo Ink Mfg. Co., Ltd .: "VCGT-K") is printed on a colored vinyl chloride resin sheet by a gravure printing method and a transparent vinyl chloride sheet are doubling embossed. A decorative sheet was obtained by applying embossing by the method and laminating with heat at the same time.

Comparative Example 2 The same printing was performed on the base sheet of Example 1, and the embossed sheet melt-extruded from the T-die was rolled at a roll temperature of 130 ° C. and a linear pressure of 2 as in Example 1.
A hot pressing roll of 0 kgf / cm was applied to obtain a decorative sheet.

Comparative Example 3 The same printing was applied to the base sheet of Example 1, and the same corona treatment was applied to the embossed sheet melt-extruded from the T-die as in Example 1, and the same adhesive was used. Was applied at 3 g / m ² with a gravure coater, dried, and laminated with the same hot pressure roll to obtain a decorative sheet.

Comparative Example 4 The same printing was performed on the substrate sheet of Example 1, the same adhesive was applied on the printed surface by a comma coater at 10 g / m ² and dried, and in the same manner as in Example 1. The embossed sheet melt-extruded from the T-die was attached to the same hot-press roll to obtain a decorative sheet.

The decorative sheet thus obtained was used for 18
It was subjected to 0 ° T-type peeling and the peeling strength and ink adhesion were observed. In addition, the depth of the embossing applied was measured by a surface roughness meter to evaluate what percentage of the depth of the embossing plate was included. Further, the obtained embossed decorative sheet is 100
After standing in an atmosphere of ° C for 5 hours, the shape of the emboss was measured by a surface roughness meter to evaluate what percentage of the initial emboss depth remained. Further, the air remaining on the laminated surface was evaluated visually and by a microscope. The results are shown in Table 1.

[0035]

[Table 1]

As is clear from Table 1, it goes without saying that the sheet obtained according to the present invention is a dechlorinated vinyl decorative sheet, and the embossing applied faithfully reproduces the embossed plate, Moreover, there was no change in the depth of embossing at high temperature, and there was no mixing of air after lamination. Further, the peel strength was 3.5 kgf / in (Example 1).

On the other hand, the conventional vinyl chloride resin is inferior in both the emboss reproduction rate and the emboss retention rate to those obtained according to the present invention (Comparative Example 1). Further, the method using heat and pressure has a weak peeling strength, and air is mixed in, resulting in poor designability (Comparative Example 2). Further, even when the back surface of the embossed sheet was coated with an adhesive, when the coating amount was 3 g / m ² , the peel strength was sufficient, but air was mixed in and the designability was poor (Comparative Example 3). Further, even when the coating amount was 10 g / m ² , the adhesive applied to the base material sheet side also had sufficient peeling strength, but air was mixed and the designability was poor (Comparative Example 4).

[0038]

As described above in detail, according to the method of the present invention, since vinyl chloride is not used at all, there is no fear of environmental problems and a decorative sheet having physical properties equivalent to or even better than vinyl chloride is obtained. In particular, since the resin is extruded and embossed, the embossing reproducibility and the heat resistance are excellent, and the decorative sheet can be obtained without the inclusion of air on the bonding surface.

[0039]

[Brief description of drawings]

1 is a cross-sectional view of a decorative sheet according to the present invention.

FIG. 2 is a sectional view of an embossed sheet according to the present invention.

FIG. 3 is a schematic view showing an embodiment of a method for manufacturing a decorative sheet according to the present invention.

FIG. 4 is a schematic view showing an example of a conventional method of manufacturing a decorative sheet.

[Explanation of symbols]

1 ... Base sheet made of olefin resin 2 ... Design ink 3 ... Adhesive 4 ... Olefin transparent thermoplastic resin
5 ... Embossed pattern 6 ... Wiping ink 7 ... Top coat layer 8 ...
Embossed sheet 9 ... Printed base sheet 10 ... Decorative sheet 11
... Emboss strike-through 12 ... Extruder 13 ... T die 14 ... Embossed cooling roll 15 ... Pressure roll 16 ... Backup roll 17 ...
Corona treatment device 18 ... Adhesive coating device 19 ... Drying device 20 ... Hot-press roll

Claims (1)

[Claims] 1. An embossed sheet obtained by extruding a base sheet made of an olefinic resin having an arbitrary printed pattern and a molten olefinic transparent thermoplastic resin onto an embossed cooling roll. in the decorative sheet comprising Te, wherein after the corona-treated on the back surface of the embossed sheet manufacturing method of decorative sheet, characterized in that the adhesive 5 to 15 g / m ² coating.