JP6476774B2 - Method for producing film for decorative sheet - Google Patents

Description

  The present invention relates to a method for producing a film used for a decorative sheet used for a building interior material, a surface material for joinery, a surface material for home appliances, and the like. After being laminated with a resin layer, etc., it is used as a decorative board by sticking to, for example, wooden boards, inorganic boards, metal plates, etc. The present invention relates to a method for producing a suitable decorative sheet film.

  Conventionally, decorative sheets made of soft polyvinyl chloride resin have been widely used because they have excellent processability and non-flammability, but from the viewpoint of environmental compatibility in recent years, toxic gases, etc. are generated during incineration after disposal. The occurrence of such a problem has been regarded as a problem, and a decorative sheet using a polyolefin resin instead of the polyvinyl chloride resin has been proposed. However, when a polyolefin resin is used, the generation of toxic gas during combustion is suppressed, but the polyolefin resin is one of highly flammable resins and it is difficult to satisfy nonflammability. .

  As a means for reducing the combustibility of a decorative sheet using a polyolefin-based resin, a method of reducing the combustibility by reducing the thickness of the decorative sheet can be considered, but as a means for reducing the thickness of the polyolefin-based resin sheet, a uniaxial or biaxial stretching device There is a means using.

  On the other hand, when a polyolefin-based resin is used as a decorative sheet, it is necessary that the printability and ink adhesion are excellent, but the polyolefin-based resin has been inferior to the vinyl chloride resin in ink adhesion.

  Therefore, when printing on the surface of the polyolefin-based resin sheet, in order to improve ink adhesion, a mat-like embossing is performed on the surface of the sheet in advance to give an ink anchor effect. When trying to make a film for a decorative sheet with a thin film, the fine unevenness due to the embossing process disappears, so the adhesion between the ink and the film for the decorative sheet deteriorates. There was a problem of easy peeling.

Japanese Examined Patent Publication No. 4-31301

  In view of such a situation, the present invention provides a decorative sheet, by producing a film for a decorative sheet by stretching a sheet made of a polyolefin-based resin by stretching, by eliminating the fine irregularities of the embossing of the sheet surface by stretching. It is an object of the present invention to provide a method for producing a decorative sheet film that does not impair the adhesion between the film for printing and the printing ink.

As a means for solving the above problems, the invention according to claim 1 is a method for producing a film for a decorative sheet in which a sheet mainly composed of a resin containing polypropylene is thinned by stretching. When stretching using a plurality of rolls having different surfaces, a single or a plurality of rolls of the plurality of rolls using a roll having a non-mirror surface on the surface , the surface of which is uneven by a sandblast method, It is a manufacturing method of the film for decorative sheets characterized by forming the fine uneven | corrugated damage | wound by a slip phenomenon on the film for cosmetics.

The invention according to claim 2 is a method for producing a film for a decorative sheet in which a sheet mainly composed of a resin containing polypropylene is thinned by stretching, and the surface of the sheet is not a mirror surface before stretching. It is a method for producing a decorative sheet film, characterized in that fine irregularities due to a slip phenomenon are formed by passing a preheating roll of a book, and fine irregularities are left on the stretched decorative sheet film.

  According to the present invention, when a sheet made of polyolefin resin is made into a thin film by stretching to produce a decorative sheet film, the decorative sheet film and the printing ink are produced by the disappearance of the fine unevenness of the sheet surface embossing by stretching. It is possible to provide a method for producing a film for a decorative sheet that does not impair the adhesion of the film.

FIG. 1 is a partial schematic view of a stretching apparatus showing an example of a method for producing a decorative sheet film according to the present invention.

  Hereinafter, a detailed description will be given of embodiments for carrying out the present invention with reference to the drawings. FIG. 1 is a partial schematic view of a stretching apparatus showing a method for producing a decorative sheet film according to the present invention.

  The sheet (1) made of polyolefin resin is carried into the stretching device (40) in the direction of the arrow (3). The stretching device (40) is composed of a plurality of rolls and is roughly divided into three zones. From the right in FIG. 1, a preheat zone (20), a stretching zone (10), and a cooling zone (30). The decorative sheet film (2) is produced by the stretching device (40) via these three zones.

  In the present invention, a sheet made of a polyolefin-based resin is provided on a decorative sheet film by providing fine unevenness due to a slip phenomenon on the surface of the decorative sheet film with a single roll or a plurality of rolls whose surface is not a mirror surface using a stretching device. The method of manufacturing is provided.

  First, a method for producing a decorative sheet film using a stretching roll will be described. The stretching rolls are represented as a pair of rolls in the stretching zone (10) in the example of FIG. In a normal stretching apparatus, the pair of stretching rolls has a mirror finish. The mirror-finished roll referred to here is a roll that has been subjected to a mirror finish such as buffing or a chrome plating process, and has been subjected to a mirror finish with a surface roughness Ra = 0.1 or less.

  The pair of stretching rolls can uniaxially stretch the polyolefin resin sheet in the flow direction by making a difference in the peripheral speed. For example, when the peripheral speed of the stretching roll (11) is 10 m / min, the sheet can be stretched three times in the flow direction by setting the peripheral speed of the stretching roll (12) to 30 m / min.

The polyolefin-based resin sheet is made by a T-die film forming method or a calendar film forming method, and fine irregularities are imparted to the sheet surface by an embossing roll during film formation. This fine unevenness improves the printability of the printing ink and improves the adhesion of the ink by the anchor effect, ensuring the resin layer formation on the ink layer in post-processing and the interlayer strength after film lamination. .

  However, when this sheet is made into a thin film using a stretching device to produce a decorative sheet film, fine irregularities on the surface are lost with stretching, and the adhesion between the decorative sheet film and the printing ink is impaired.

  According to the present invention, the fine unevenness is newly added to the surface of the decorative sheet film in the stretching zone by using the fine unevenness on the surface of the pair of stretching rolls of the stretching device. Can be created.

  This is due to the so-called slip phenomenon that occurs when the surface of a pair of stretching rolls subjected to fine unevenness and the surface of the polyolefin resin sheet come into contact with each other. This is because new fine uneven scratches are brought about. The fine irregularities can improve the printing suitability of the printing ink, increase the ink adhesion by the anchor effect, and ensure the interlayer strength after the resin layer formation and film lamination on the ink layer in the post-processing.

  Since the pair of rolls are in contact with the front and back surfaces of the polyolefin-based resin sheet, new fine irregularities can be caused on both the front and back surfaces of the decorative sheet film. The formation of fine irregularities not only on the printed surface but also on the back surface is advantageous for ensuring the adhesiveness of the adhesive when the decorative sheet is bonded to a plate or the like.

  When it is only necessary to form fine irregularities on the printing surface, only the roll of the pair of rolls that hits the surface on which the fine irregularities are to be formed should be a roll that is not a mirror surface. As a method for forming a roll having a non-mirror surface by applying fine unevenness to the surface of the roll, for example, there is a method in which a fine unevenness is applied to the roll surface by a sand blasting method to make a mat finish.

  The stretching roll used for normal stretching can be composed of a plurality of three or more rolls in addition to a pair of rolls. Also in this case, a fine unevenness is formed on the roll, and a so-called slip phenomenon that occurs when the surface of the roll and the surface of the polyolefin-based resin sheet come into contact causes a fine scratch on the contact surface. Brings new fine irregularities to the surface of the surface. In order to form new fine irregularities on both the front and back surfaces, it is necessary to form fine irregularities on at least two rolls.

  Then, the manufacturing method of the film for decorative sheets by the roll of a preheat zone (20) is demonstrated. The preheating zone includes one or more preheating rolls. For example, the preheating zone may include two preheating rolls (21) and a preheating roll (22), or more. The preheating roll is provided for the purpose of preheating the polyolefin resin sheet before entering the stretching zone.

  By forming fine irregularities on the surface of this roll group, fine irregularities can be made on the film surface. The so-called slip phenomenon causes a fine scratch on the contact surface with the polyolefin-based resin sheet, resulting in a new fine uneven surface on the surface of the decorative sheet film. In order to form new fine irregularities on both the front and back surfaces, fine irregularities may be formed on at least two roll surfaces.

  Because the fine irregularities formed on the contact surface with the polyolefin resin sheet due to rubbing by the preheating roll, so-called slip phenomenon, are scratches, and unlike the fine irregularities of embossing when the polyolefin resin sheet is formed, stretching Even when stretched in a zone to form a film for a decorative sheet, it has a characteristic that fine irregularities are not easily damaged.

  In both the method for producing a decorative sheet film using a stretching roll and the method for producing a decorative sheet film using a preheating roll, a single-layer polyolefin resin sheet may be used, and a plurality of layers are laminated. You can use the same thing.

  As a standard for evaluating fine irregularities formed on the decorative sheet film according to the present invention, it is an index of the surface roughness standard such as JIS, and the surface roughness index generally normalized by the symbol of Rv is the peel strength. It turns out that there is the most correlation. Rv is the maximum valley depth of the roughness curve, and represents the maximum value of the valley depth of a contour curve such as a cross-sectional curve or a waviness curve at the reference length.

  According to the description of the mode for carrying out the present invention so far, the sheet surface made of polyolefin resin is thinned by stretching, and the embossing of the sheet surface by stretching when producing a film for decorative sheets is fine. It can be seen that it is possible to provide a method for producing a decorative sheet film that does not impair the adhesion between the decorative sheet film and the printing ink due to the disappearance of the unevenness.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to this. In Example 1, Example 2, Comparative Example 1, and Comparative Example 2, decorative film film samples were prepared using the following materials and procedures. The description will be made with reference to FIG.

<Example 1>
The following sheets of polyolefin were used.
Composition: Kneaded resin of polypropylene resin and inorganic color pigment.
Sheet thickness: 120 μm, sheet width: 1310 mm.
The conditions of the stretching apparatus are as follows.
Preheating roll: mirror roll.
Preheating roll temperature: 105 ° C.
Drawing roll: The following were used instead of the mirror roll.
Stretch roll diameter: 250 mm
Stretch roll surface shape: mat finish by sandblasting Stretch roll surface roughness: Ra = 1.13
Number: Two stretching rolls (11) and two stretching rolls (12) in total.
Stretching conditions: Uniaxial stretching was performed with the peripheral speed of the first stretching roll (11) being 10 m / min and the peripheral speed of the second stretching roll (12) being 30 m / min.
Winding tension: 60N.

<Example 2>
The following sheets of polyolefin were used.
Composition: Kneaded resin sheet of polypropylene resin and inorganic color pigment sheet thickness: 120 μm, sheet width: 1310 mm.
The conditions of the stretching apparatus are as follows.
Preheating roll: Matt finish by sandblasting.
Preheating roll surface roughness: Ra = 1.13
Number: Two preheating rolls (21) and two preheating rolls (22) in total.
Preheating roll temperature: 105 ° C.
Stretch roll: mirror roll.
Stretch roll diameter: 250 mm.
Stretching conditions: the first stretching roll (11) has a peripheral speed of 10 m / min, the second stretching roll (12)
The uniaxial stretching was performed at a peripheral speed of 30 m / min.
Winding tension: 60N.

<Comparative Example 1>
The polyolefin sheet used was the same as in Example 1.
The conditions of the stretching apparatus are as follows.
The two stretching rolls used in Example 1 were replaced with mirror rolls (returned) to create a decorative sheet film sample. Only this portion is different from the first embodiment.

<Comparative example 2>
The polyolefin sheet used was the same as in Example 2.
The conditions of the stretching apparatus are as follows.
The two preheating rolls used in Example 2 were replaced with mirror rolls (returned) to prepare a decorative sheet film sample. Only this part is different from the second embodiment.

<Evaluation method>
(1) Surface shape The surface roughness Rv of the decorative sheet film prepared in Example 1, Example 2, Comparative Example 1, and Comparative Example 2 was measured.
(2) Peel strength The adhesion of ink is evaluated by peel strength.
Printing was performed on the decorative sheet films prepared in Example 1, Example 2, Comparative Example 1, and Comparative Example 2, and an anchor coat layer was applied thereon with a thickness of 10 μm, and further a transparent polypropylene layer was 70 μm. After stacking by thickness, the test piece was affixed to a steel plate.
The peel test was conducted as a 180 degree peel test.
A peel strength of 35.0 Mpa or more is considered good peel strength, and a peel strength of less than 35.0 Mpa is bad.
(3) Appearance observation of peeled portion The appearance of the peeled portion was observed visually and with a microscope.
Aggregation peeling of the anchor coat layer is judged to have good laminate strength.
Interfacial peeling between the ink surface and the decorative sheet film is judged as a poor laminate strength.
The above evaluation results are shown in Table 1.

延伸ロールを、マット仕上げにした効果は、実施例１と比較例１を対比して判断できるが、表面粗さＲｖにおいて実施例１において微細な凹凸がよりはっきりと形成されていることがわかる。

The effect of matting the drawing roll can be judged by comparing Example 1 and Comparative Example 1, but it can be seen that fine irregularities are more clearly formed in Example 1 in the surface roughness Rv.

  The effect of matting the preheating roll can be judged by comparing Example 2 and Comparative Example 2, but it can be seen that fine irregularities are more clearly formed in Example 2 in terms of surface roughness Rv.

  The peel strength is larger in both Example 1 and Example 2 than in Comparative Example 1 and Comparative Example 2, and the quality is clearly determined at 35.0 Mpa, which is a standard for judging the laminate strength.

  The correlation coefficient between Rv and peel strength was 0.96, which was a high result as described above, and this also showed the effect of the present invention.

The difference between the example and the comparative example is also the same by observing the appearance of the peeled portion. In the examples, the anchor coat layer is agglomerated and peeled. In each of the comparative examples, it was determined that the laminate strength was poor because of the interfacial peeling between the ink surface and the decorative sheet film. The interfacial peeling between the ink surface and the decorative sheet film in the comparative example is a result of confirming the weak adhesion of the ink.

  Based on these results, according to the present invention, when a sheet made of a polyolefin resin is made into a thin film by stretching to produce a decorative sheet film, the film for the decorative sheet is lost due to the disappearance of fine irregularities in the embossing of the sheet surface by stretching. It was verified that it was possible to provide a method for producing a film for a decorative sheet that did not impair the adhesion between the ink and the printing ink.

DESCRIPTION OF SYMBOLS 1 ... Sheet | seat consisting of polyolefin resin 2 ... Film for decorative sheets 3 ... Arrow 10 ... Stretching zone 11 ... Stretching roll 12 ... Stretching roll 20 ... Preheating zone 21 ... -Preheating roll 22 ... Preheating roll 30 ... Cooling zone 40 ... Stretching device

Claims (2)

In a method for producing a decorative sheet film in which a sheet mainly composed of a resin containing polypropylene is thinned by stretching, when the sheet is stretched using a plurality of rolls having different peripheral speeds, A decorative sheet characterized by using a roll having a non-mirror surface on the surface by sandblasting as a single or a plurality of rolls , and forming fine uneven scratches due to a slip phenomenon on the decorative sheet film Film manufacturing method. In a method for producing a film for a decorative sheet in which a sheet mainly composed of polypropylene-containing resin is thinned by stretching, the sheet is caused by a slip phenomenon by passing a single or a plurality of preheating rolls whose surface is not a mirror surface before stretching. A method for producing a decorative sheet film, comprising forming fine irregularities and leaving fine irregularities on the stretched decorative sheet film.

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