JP3139271B2 - Method for producing thermoplastic resin embossed sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a thermoplastic resin sheet having an embossed surface.

[0002]

2. Description of the Related Art The surface of a thermoplastic resin sheet, which is provided with fine irregularities to remove gloss, is used as a surface plate for a transmission type display, an illumination cover, an interior / exterior component such as a bicycle, a train, an airplane, or the like. Widely used for exterior parts of household electrical equipment.

[0003] Conventionally, as a method for producing a thermoplastic resin sheet having fine irregularities or a specific pattern on the surface, as a roll constituting a roll unit in extrusion molding, a grain pattern or a specific pattern is formed on the roll surface. Transfer of a pattern to the surface of a resin sheet is performed by using, for example, a so-called emboss roll.

[0004]

The method of molding using an embossing roll is suitable for mass-producing a resin sheet on which a certain pattern applied to the embossing roll is transferred, but a variety of different patterns can be produced. In order to manufacture the transferred resin sheet, it is necessary to provide an embossing roll corresponding to the transferred resin sheet. In addition, since the roll is replaced, the production has to be stopped for several hours, resulting in low productivity.

Accordingly, the present invention provides a method for easily and efficiently producing a thermoplastic resin sheet on which various patterns and patterns are transferred by using a known thermoplastic resin sheet producing apparatus.

[0006]

According to the present invention, when a molten thermoplastic resin is produced through three or more finishing roll units to produce a resin sheet, a gap between the second and subsequent rolls of the roll unit is formed. And a method of manufacturing a thermoplastic resin embossed sheet, wherein a sheet-like material having a concavo-convex pattern is interposed between separately prepared surfaces.

As the thermoplastic resin in the present invention, a resin which can be plastically processed by heating, such as an acrylic resin, a polycarbonate, a styrene resin, a vinyl chloride resin, a polyolefin, a polyester, a polyacetal, a fluororesin, or a polyamide, is applicable. .

[0008] The thermoplastic resin embossed sheet of the present invention is a general term for plates and sheets having a thickness of about 0.3 to 20 mm. The patterns and patterns provided by embossing have irregularities, such as fine irregularities, that is, textures, mats, matte, rough irregularities called rough texture, or various patterns. Refers to a pattern.

The method for producing a resin sheet from the molten thermoplastic resin of the present invention through two or more finishing roll units is a well-known typical method for producing a resin sheet or film. For example, "Plastic Processing Technology Handbook" (October 20, 1979, published by Nikkan Kogyo Shimbun)
Pages 254 to 260: "Plastic sheet extrusion technology" (issued by the Industrial Research Institute on May 29, 1969): "Plastics" vol.33, No. 10 (October 1982, October 1982)
(Issued by the Industrial Research Council) pages 49-56, "Plastic sheet molding technology with improved appearance": "Extruder", "die", "glossy" as described in JP-B-61-46305, etc. Roll unit (polishing roll machine) "," roller table "," ear trimming device "," take-up roll ",
There is a so-called extrusion molding using a device having a configuration of “cutting and stacking device”. In addition, as described on pages 323 to 360 of the "Handbook of Plastics Processing", there is a so-called calendering method using an apparatus having a "kneading device" and a "calender roll" for resin. The number of finishing rolls is preferably 2 or more, and more preferably 3 or more.

In the above-mentioned molding method and processing method, the molten resin formed into a sheet in the preceding step is subjected to the finishing roll unit 1
The sheet is sandwiched in the gap between the second and second rolls, and the thickness of the sheet-like resin is set to a predetermined value.

The gap between the rolls of the finishing roll unit referred to in the present invention is expressed in the order of the rolls along the flow of the plate-like resin, depending on the number of rolls. The second and third gaps, and the subsequent gaps between rolls, are referred to as the number of rolls.

A sheet having a separately prepared surface with an uneven pattern is sandwiched between the rolls of the finishing roll unit. The position at which the sheet is sandwiched may be any position as long as it is a gap between the rolls,
At the entrances of the first and second roll gaps, a resin pool called a bank is likely to be generated, and if the sheet-like material is sandwiched therebetween, the thickness of the obtained embossed sheet tends to be uneven, so that the finishing roll is used. It is preferable to use three or more roll units to sandwich the sheet from the gap between the second and subsequent rolls.

By using three or more finishing rolls and sandwiching the sheet from two places between the rolls, a thermoplastic resin sheet embossed on both sides can be obtained.

The separately prepared sheet-shaped article having an uneven pattern on its surface is called a sheet or film depending on its thickness. The concavo-convex pattern is a pattern having fine irregularities generally called a matte or mat on the surface of the sheet-like material, or a pattern such as a grain of wood or a hairline expressed by irregularities. This can be obtained by directly molding the sheet-like material or coating the sheet-like material with a matting agent or the like. The material does not exhibit adhesiveness with the thermoplastic resin, and the uneven pattern applied to the sheet material does not disappear even at the temperature and pressure when the thermoplastic resin sheet is in contact with the finishing roll. Any material may be used as long as it exhibits properties. For example, when the thermoplastic resin sheet is an acrylic resin, the sheet-like material is aluminum, stainless steel,
Examples include copper, nylon or polyethylene terephthalate.

As the sheet-like material, one having a width and length corresponding to the width and length of the thermoplastic embossed sheet to be produced is used.
Above all, when a large amount of thermoplastic embossed sheet is manufactured, the sheet-shaped material is sequentially unwound from a roll, and after passing through a finishing roll unit after entering through the gap between the rolls, a thermoplastic resin sheet is formed. Is preferably released from the thermoplastic resin sheet at a temperature equal to or lower than the glass transition temperature or near room temperature, and can be wound up again.

If the sheet-like material is as rigid and rigid as possible, it may be simply unwound and sequentially sandwiched between the rolls, but the sheet-like material is thin and soft. It is necessary to maintain a uniform surface by applying tension in the flow direction and the width direction for those which are easily wrinkled or twisted.
The method of applying both tensions may be a known method.

In order to apply tension in the flow direction, instead of unwinding a sheet-shaped material by free rotation to unwind it,
Use a feeding device that is slightly braked and requires a certain amount of pulling force to unwind the sheet. In order to make the tension uniform, one of the simple methods is to install a guide roll movable up and down or left and right in accordance with the tension from the feeding device to the gap between the rolls so as to reduce the fluctuation of the tension.

To apply a tension in the width direction, one of the simple methods is to use a so-called expander roll in which the diameter at the center is maximum and the diameter at the end is smaller between the gap between the feeding device and the roll. .

The sheet-like material that has passed through the finishing roll may be wound again by a known method such as using a winder. Further, if the wound front end is joined to the rear end to be endless, it is suitable for mass production of a thermoplastic resin embossed sheet.

[0020]

According to the method of the present invention, by using a general thermoplastic resin sheet manufacturing apparatus using a roll unit, a sheet-like material having a concavo-convex pattern on its surface is sandwiched between roll gaps. Thus, a thermoplastic resin embossed sheet can be manufactured, and by exchanging the sheet-like material, a thermoplastic resin embossed sheet having various different patterns can be manufactured. In other words, embossing rolls were conventionally used to manufacture embossed sheets.However, to change the embossed pattern, the embossing rolls must be replaced. I had to. However, in the present invention, a variety of products can be efficiently manufactured simply by exchanging the sheet-like material without stopping the supply of the molten resin sheet to be supplied to the roll unit and the driving of the roll unit. Further, the sheet material can be used repeatedly.

[0021]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples. FIG. 1 shows the apparatus used in the examples. The equipment used is as follows.・ Extruder: Screw diameter 40mm, uniaxial, manufactured by Tanabe Plastics Machinery Co., Ltd. ・ Flat die: width 220 mm, lip gap 7mm ・ Finishing roll: diameter 200mm, width 300mm, 3 pieces, temperature is 95 ℃, 105 in order ° C 110 ° C.

Examples 1 and 2 Acrylic resin (Sumipex B Sumitomo Chemical Co., Ltd.)
Resin temperature from the extruder-flat die
At 70 ° C, a resin sheet having a thickness of 20 mm / Hr and a thickness of 3.0 mm was extruded. 70μm thickness with one side matted as a sheet
Polyethylene terephthalate film (Lumimat
Using # 300D type and Lumimat # 400 Torres, manufactured by Panac Co., Ltd.), the mat was supplied in a direction in which the mat surface was in contact with the extruded resin sheet. The surface roughness of each of the used film and the obtained resin embossed sheet was measured using a surface roughness meter (Surfcom 550A, manufactured by Tokyo Seimitsu Co., Ltd.) using a center line average roughness (Ra) and a maximum height (Rmax). ) Was measured. Table 1 shows the results. Each of the thermoplastic resin plates obtained by this method had a sufficiently transferred irregularity on the film surface.

[0023]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus used in an embodiment of the present invention.

[Explanation of symbols]

 1: 1st finishing roll 2: 2nd finishing roll 3: 3rd finishing roll 4: flat die 5: molten resin sheet 6: sheet-like material with surface irregularity pattern 7: sheet-like material feeding device 8: sheet-like material peeling Apparatus 9: embossed thermoplastic resin sheet

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 59/00-59/18

Claims (1)

(57) [Claims] When producing a resin sheet of a molten thermoplastic resin through three or more finishing roll units, a gap between the second and subsequent rolls of the roll unit is provided.
A method for producing a thermoplastic resin embossed sheet, characterized by sandwiching a sheet-like material having an irregular pattern on a separately prepared surface.