JPS6031951A - Heat sealing method for polyethylene high foaming body - Google Patents

Abstract

PURPOSE:To heat-seal a high-performance polyethylene foamed sheet simply by executing heat seal processing under conditions selected by the thickness of a blank sheet and an expansion ratio and each executing the continuation of pressing after the interruption of currents and the spraying of cooling air for specific times. CONSTITUTION:The conditions of thermal processing are set previously by operating a working voltage regulator V and a conduction time regulator TM installed to an operation board 2. Proper processing conditions among onces in the table are selected according to the thickness and expansion ratio of the 0.1- 4.0mm. thickness and 3-40 times expansion ratio of a polyethylene foam containing EVA as a heat-sealed blank sheet. Since the conduction time is displayed by the lighting of a timer display lamp L fitted on the operation board 2, foot- operated pressing is continued for 2-5sec particularly after the putting-out of the lamp and pressing is released while cooling air is sprayed for 1-5sec, thus completing polymerization action, then allowing heat sealing. Accordingly, the blank sheet consisting of the high-performance polyethylene foam which has been regarded as impossible can be heat-sealed simply.

Description

[Detailed description of the invention] (Object of the invention) EV that cannot be thermally bonded among polyethylene high foams
A-filled polyethylene foam (closed cell), foaming ratio 3~
The present invention relates to a heat-sealing method that enables heat-sealing of sheets of material approximately 40 times larger.

(Prior technology) A foamable sheet made by mixing polyethylene, a foaming agent, and special additives is molded, irradiated with electron beams, and then made into a long sheet-like foam using a special foaming machine.The material has excellent thermal processability. Although it cannot be subjected to high frequency processing, it can be heat-sealed and heat-fused, so it has a wide range of uses as an industrial FR product.

As the technological development of this family of materials progresses, EVA-containing polyethylene foam (closed cell) is being used in a wider range of applications as a new material that is flexible, tough, and has excellent skin strength. For this reason, conventional bonding methods using thermal cutting (heating the welded part until it breaks and then melting it in a linear shape) have been used, and the bonding strength has been weak, which has been a practical problem.

(Structure of the Invention) This invention solves the above-mentioned problems, selects the thermal processing conditions of the impulse sealer depending on the thickness of the material sheet and the expansion ratio, and sets appropriate values for each of the working voltage, energization time, and pressure bonding force. The material is then heat-sealed, but even after the heating current is cut off, pressure is maintained for 2 to 5 seconds before being released, and cooling air is then blown for 1 to 5 seconds. This is a method for heat-sealing high-foamed polyethylene.

Practical examples will be explained below with reference to figures and tables.

The figure is a perspective view of an impulse sealer used for heat sealing. The required heat-sealed part of the material sheet is inserted between a pair of upper and lower pressure plates D1 and heating plates H in front of the workbench T in front, and a foot pedal PE is created by grooves that interlock from the pressure plate.
Pressure can be adjusted by stepping on the button. Operating voltage regulator ■ and energization time l1lI regulator TM set in different numbers on operation panel 2
Set the heat processing conditions in advance by operating .

EVA-containing polyethylene foam (closed cell) +1 of heat-sealable material sheet 0.1-4.0 mm, foaming ratio 3-4
0 times (forming main raw materials Lt, npE, filler EVA to increase texture and adhesive slackness), select an appropriate one from among the thermal processing conditions shown below depending on the foaming ratio. 'The energization time is displayed by lighting up the timer display lamp L on the operation panel, so when the lamp goes out, keep pressing the foot for 2 to 5 seconds, then release it and blow cooling air. If it is carried out for 1 to 5 seconds, the polymerization action is completed and heat fusion can be achieved.

Note that hydraulic pressure or pneumatic pressure may be applied instead of foot pressurization.

(Effect of the invention) This type of material, which has been widely used in the industrial field because it can easily heat-seal material sheets of high-performance polyethylene foam that could not be heat-sealed, is being further developed and utilized. The effect is great.

[Brief explanation of drawings]

The figure is a perspective view of the impulse sealer. (Explanation of symbols of main parts) V: Working voltage regulator TM + energizing time li @ device D: Pressure plate H: Heating plate

Claims (1)

[Claims] Expansion ratio: 3 to 40 times What is the required fusion area of the VA-containing polyethylene foam (closed cell) material sheet? Insert the impulse sealer between the heating plate and the pressure plate, and select the appropriate value from 9 for the operating voltage of 20 to 40 volts, energizing time of 0.1 to 3.0 seconds, and pressure of 20 to 80. A method for thermally fusing polyethylene high foams, which comprises applying heat and pressure, maintaining pressure for 2 to 5 seconds using a current breaker, and then blowing cooling air for 1 to 5 seconds.