JPH0263819A - Both side embossing processing method - Google Patents

Abstract

PURPOSE:To obtain a molded sheet having beautiful external appearance quality by method wherein a resin sheet which is melted and extruded is passed through between a metallic roll to the surface of which embossing processing is performed and a rubber roll which is embossing-processed similarly while being pinched in a molten state of the resin sheet and both the surfaces of the resin sheet are embossing-processed simultaneously. CONSTITUTION:A molten resin sheet 4 is pinch-pressed under linear pressure of 50kg/cm<2> between a first rubber roll 1 obtained by making use of a rubber roll which is embossing-processed and with Shore hardness of Hs 60-70 and a temperature of 30-60 deg.C for the surface of the first roll and a second metallic roll 2 whose surface is embossing-processed similarly and with a temperature of 100-180 deg.C. Then a recessed deformation is generated on the first roll 1 at a transfer position 5 of embossment. Then in cooperation with facial pressure welding of both the surfaces of the molten resin sheet 4 to both the rolls 1, 2, embossing patterning is performed between the rolls 1, 2 while the molten resin sheet 4 itself directly after discharge of a mouth piece 8 has a high temperature and low viscosity. Therefore, an embossing pattern can be transferred reliably and clearly to both the surfaces of the molten resin sheet 4.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a double-sided embossing method, and more particularly, to a simple embossing method that simultaneously and clearly embosses a pattern on both sides of a resin sheet immediately after melt extrusion. .

(Prior art and its problems) In conventional plastic sheet extrusion molding, the method for forming embossed patterns on both sides of a molded product is to move from the mouthpiece G of the extruder F in the direction of the arrow, as shown in the side view in Figure 2. Using three metal rolls, the extruded molten resin sheet D is first passed under pressure between a lower roll A and a middle roll B whose surface is embossed to form a pattern on one side of the molten resin sheet D. Sheet E is then passed under pressure between the middle roll B and an upper roll C whose surface is embossed in the same manner as above to form a pattern on the other side of the molten resin sheet D to form a double-sided embossed pattern. A common processing method is to obtain .

However, in the above conventional method, the molten resin sheet D is cooled while reaching the upper roll C, and the viscosity of the surface of the sheet 59 increases and becomes close to a solidified state, resulting in partial transfer failure or overall The embossed pattern becomes shallower,
There was a problem in that the embossed pattern on the roll surface was insufficiently transferred to the sheet surface, such as the front embossment and the back embossment becoming uneven.

(Means for Solving the Problems) The present invention is a double-sided embossing method for solving the above-mentioned problems, and its gist is to provide a metal roll whose surface is embossed and a metal roll which is also embossed. This double-sided embossing method is characterized by simultaneously applying embossing to both sides of the resin sheet by passing a melt-extruded resin sheet while being compressed between a rubber roll made of rubber.

The present invention will be specifically explained below with reference to the drawings.

As shown in a side view of an embodiment of the present invention in FIG. 1, the present invention is characterized in that a molten resin sheet 4 extruded from a mouthpiece 8 of an extruder 7 in the direction of the arrow is transferred to a rubber roll ( A metal roll (hereinafter referred to as "Rule 20") with the same embossed surface as 1 (hereinafter referred to as "Rule 20")
The embossed pattern is simultaneously transferred to both sides of the molten resin sheet 4 at the emboss transfer section 5 while being passed under pressure between the molten resin sheet 4 and the molten resin sheet 4. ) 3 while cooling in the direction of the arrow to obtain a molded sheet 6 with clear embossed patterns transferred to both sides.

The 10th rule 1 is preferably a rubber roll with a shore hardness of Hs 60 to 70. If it is soft below Hs 60, it is difficult to obtain the thickness accuracy of the molten resin sheet 4, and if it is hard and hard above Hs 70, it tends to result in unclear transfer. The temperature condition is the 10th
- Rule 1 is 30-60°C, and 20th - Rule 2 is 100°C.
~180° C. is preferable; below the above ranges, the emboss transfer tends to be insufficient, and above the above ranges, the molten resin sheet 4 tends to stick to the roll surface, causing trouble.

Further, the temperature of the 30th rule 3 is 80 to 180'C as in the conventional case, which is a suitable temperature range for taking over the molten resin sheet 4 after the transfer while cooling it.

Furthermore, the clamping force between the 10th rule 1 and the 20th rule 2 may be in the range of 20 to 80 hg/■ as a linear pressure, and if it deviates from this range, it will be difficult to obtain the predetermined thickness accuracy of the molded sheet 6.

The resin used in the present invention is preferably a resin having a particularly low specific heat, such as polyvinyl chloride, ABS resin, polystyrene, or acrylic resin.

(Function of the invention) In the present invention, a rubber roll having the shore hardness and temperature conditions as described above is used, and the surface of the 10th rule 1 is embossed, and the surface of the roll 1 is embossed. When the molten resin sheet 4 is pressed under the above-mentioned linear pressure between the metal No. 20-ru 2 under the temperature conditions, the No. 10-ru 1 causes concave deformation at the embossed transfer portion shown in FIG.
Since both surfaces of the molten resin sheet 4 are in surface pressure contact with both rolls 1.2, the temperature of the molten resin sheet 4 itself immediately after being discharged from the nozzle 8 is high, and while the melt viscosity is low, the roll 1.
The embossed pattern can be reliably and clearly transferred to both sides of the molten resin sheet 4 by applying the embossed pattern between the two.

(Example) Temperature 20 discharged from the mouthpiece 8 of the extruder 7 shown in FIG.
No. 10 - The molten polyvinyl chloride resin sheet 4 at 5°C was embossed on the surface of a roll made of white neoprene rubber set at a shore hardness of Hs 65 and a temperature of 45°C.
Between the 20th rule 1 and the 20th rule 2, which is a metal roll whose surface is embossed at a temperature of 140°C,
It was passed through while being compressed with a linear pressure of 50 kg/am, and then wound around a metal No. 30-ru 3 set at a temperature of 140'C and taken off while being cooled.

The obtained molded sheet 6 had a clear embossed pattern evenly provided on both sides and had a beautiful appearance.

On the other hand, according to the conventional double-sided embossing method shown in Fig. 2, the 10th-rule is a mirror-finished metal nip roll and the temperature is set to 70'C, and the 20th-rule and the 30th-rule are the surface As a result of extrusion embossing under the same conditions as in the above example, except that a transfer roll embossed with was used and a linear pressure of 50 kHz/crn was set between the two rolls, the resulting molded sheet was The transferred surface had a relatively good embossed pattern, but the embossed pattern transferred to the back surface using the 30th rule was shallow and unclear.

(Effect of the invention) Since the present invention has the above configuration, it has the following effects.

That is, a sheet immediately after being melted and discharged from an extrusion nozzle is passed through a rubber No. 10 rule whose surface is embossed and set to a predetermined hardness and temperature, and a metal No. 10 rule whose surface is similarly embossed. When the embossed patterns of both the 10th and 20th rules are transferred under pressure between the 20th and 20th rules, the embossed patterns of both the 10th and 20th rules are clearly and evenly transferred to both sides of the sheet to obtain a molded sheet with beautiful appearance quality. was completed.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the invention in side view. FIG. 2 is a side view for explaining a conventional double-sided embossing method.

Claims (1)

[Claims] A melt-extruded resin sheet is passed between a metal roll whose surface is embossed and a rubber roll whose surface is also embossed, while being compressed while still in a molten state. A double-sided embossing method characterized by embossing both sides at the same time.