JPH06190909A - Manufacture of foamed plastic corrugated medium - Google Patents

Abstract

PURPOSE:To easily manufacture a corrugated medium for corrugated board of superior heat insulation and large pressure-resistant strength by means of a formed plastic material by using an extremely simple and small-scale equipment. CONSTITUTION:A primarily foamed plastic sheet of 0.5-4mm thickness is placed on a mold set on recessed sections of a cpuple of temperature adjustable recessed and projected molds meshed with each other and having pores connected with a vacuum tank or a compressed air tank, and its surface temperature is heated up to the thermal deformation temperature plus 60 deg.C of the plastic to be processed, and then the sheet is placed on a bottom force with its temperature adjusted to 30-90 deg.C, and pressurized by the pressure of approximately 100g/cm<2>-20kg/cm<2> for 0.3-10sec while a clearance of 0.3-2.5mm is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for obtaining a continuous or discontinuous product by a simple batch method of a foamed plastic corrugated core used for a cardboard for packaging which is lightweight and has excellent heat insulating properties. . The foamed plastic as referred to in the present invention means a foamed plastic as a main component with some fibers and fillers mixed therein.

[0002]

2. Description of the Related Art Conventionally, a corrugated cardboard corrugated core is usually made of a paperboard similar to a double-sided liner. Particularly in the field where a high degree of heat insulation is required, a foamed plastic foamed product is used. It is used. However, in this case, not only is it bulky and unfoldable, but also an expensive mold is required, so it is uneconomical to prepare a separate mold for each different shape and size of the ridge. .

As a convenient method, there is a conventional method in which a foamed plastic sheet is laminated and bonded to the outer surface side of one of the conventional paperboard corrugated boards, but in this case, the printability of the surface is poor and the hygroscopicity is high. The current situation is that satisfactory results have not been obtained.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the prior art, has a small required volume, is lightweight, and has a
It can easily accommodate dimensional changes, and can be stacked in sheets when transported and stored, and can be easily assembled into the required shape when used as a stand, and also has thermal insulation properties.
We will develop a method of batch-manufacturing heat-insulating corrugated board, which is far superior to conventional corrugated board in water resistance, moisture absorption, and dew condensation prevention, as a continuous or discontinuous product with extremely simple equipment and methods. It is a thing.

[0005]

As a result of intensive research to solve the above problems, the present invention produces a corrugated core of conventional corrugated board using a foamed plastic sheet on a small scale with simple equipment. It is the invention of the method.

That is, as shown in FIG. 1, a pair of upper and lower concave and convex molds 1 and 2 are used, and pores 3 and 4 are provided in the concave portions of the molds 1 and 2, respectively. , 4 is the vacuum chamber 5
Alternatively, it is connected to the compressed air tank 5 '. Reference numerals 7 and 7'represent the clamp portions.

When corrugation is performed using the plastic sheet 6 that has been primary-foamed or incompletely foamed, the primary-foamed plastic is heated to secondary-foam, and then the thermal deformation temperature or thermal deformation of the plastic of the plastic sheet material is performed. Mold 1 below by heating plastic to + 60 ℃
Then, the upper die 2 is placed so as to engage with the unevenness of the lower die 1. In this case, the upper and lower molds 1 and 2 are squeezed until the engagement clearance between the upper and lower molds is 0.3 to 2.0 mm larger than the thickness of the primary foam plastic sheet 6. Upper and lower molds 1 and 2 in this case
Is less than the surface temperature of the foamed plastic sheet by 3
Adjust to low temperature of 0-90 ℃ for 0.3-10 seconds, about 100g
Pressurize with a pressure of ~ 20 kg / 1 cm ² . When a secondary foamed plastic sheet is used, it is suitable that the clearance between the upper and lower molds 1 and 2 is 90 to 40% of the thickness of the secondary foamed plastic sheet.

Then, the upper mold 2 is pulled upward to take out the secondary foamed plastic sheet having the unevenness. In this case, a corrugated portion having the same shape as that of the mold body is provided on the outside of the mold end portion at a slight flat portion or at least one of them for 3 to 20 m.
If about m is provided, a continuous concavo-convex sheet can be manufactured by continuously forming the clamp portion 7 in the next processing.

In the above manufacturing method, the incompletely foamed or primary foamed plastic sheet is heated to the heat distortion temperature of the plastic to be processed or the heat distortion temperature + 60 ° C. to perform the secondary foaming, and then the foamed plastic sheet Providing a skin layer using a mold whose temperature is lower than the surface temperature by 30 to 90 ° C. on either one or both sides and imparting unevenness gives a better effect on heat insulation, pressure resistance and strength. .

Further, by providing a partition weir in the groove at the same time as the groove in the mold, preferably by providing partition weirs on both the front and back sides, air flow is cut off in the corrugated core in the case of cardboard. Therefore, the heat insulation of the corrugated board is further strengthened, and at the same time, the strength against pressure is increased, the bonding conditions are improved during the bonding, and the bonding strength is improved.

[0011]

【Example】

Example 1 A polystyrene sheet having a thickness of about 1 mm, which was primarily foamed at a foaming ratio of about 8 times, was placed on the apparatus shown in FIG.
After heating up to the range of up to 130 ° C, it was placed on the lower mold kept at 50 ° C, and the upper mold adjusted to the same temperature was heated to about 1.
While maintaining a clearance of 5 mm, pressurizing with a pressure of 400 g / cm ² for about 1 second, during which the pores provided in the mold are connected to a vacuum chamber and sucked from the lower mold, and the pores of the upper mold. Was connected to the compressed air tank and air was blown from the upper mold to ensure the accuracy of the uneven shape of the work piece. Next, the upper mold was pulled up and the corrugated article of the intermediate molded polystyrene foam sheet was taken out. The molding operation was performed for one shot for about 3 seconds. Then, after applying an adhesive to the corrugated top in the usual manner, the paperboard liner was adhered while being lightly pressed to produce a foamed polystyrene corrugated core corrugated board.

Example 2 All were carried out under the same conditions as in Example 1 except that the heating temperature of the primary expanded polystyrene sheet was about 120 ° C and the mold temperature was 60 ° C.

Example 3 A polystyrene sheet having a thickness of about 1.2 mm, which was primarily foamed at a foaming ratio of 10 times on the apparatus shown in FIG. 1, was heated to a surface temperature of about 120 ° C. and then kept at 55 ° C. Place the upper mold on the lower mold and adjust the temperature to 52 ° C while maintaining a clearance of about 1.8 mm at a pressure of 300 g / cm ² for 1.5.
Pressurize for about 2 seconds, during which the pores provided in the mold are connected to the vacuum chamber, suction is performed before the lower mold, and immediately after completion, suction is performed above the upper mold, and Accurate. After that, the same procedure as in Example 1 was performed. The molding operation was performed for one shot for 4 seconds.

Example 4 Almost the same as Example 3, except that the lower mold temperature was 60 ° C., the upper mold temperature was 57 ° C., and the molding was carried out. The upper die end (clamping portion) has a corrugated shape similar to that of the die body, and the press molding temperature is continuously set at 65
Since the molding was performed at 0 ° C., and the molding process of the mold body was immediately performed, the corrugated core could be continuously manufactured. A continuous wave type core having normal strength was obtained without cracks, breakage, or poor connection at the connection points. After that, the sheet was appropriately cut and the same as in Example 1.

Example 5 Almost the same as Example 2, except that the mold temperature was 55 ° C.
The upper mold was pressed, and the lower mold was sucked to perform molding. All other conditions were the same as in Example 1.

[0016]

The corrugated core for corrugated cardboard made of foamed plastic sheets can be manufactured batchwise with extremely simple equipment. The pressure-resistant strength of the corrugated core is larger than that of the conventional corrugated corrugated board, and it is especially useful for preventing dew condensation. This is a method for manufacturing a corrugated core with excellent heat insulation.

[Brief description of drawings]

FIG. 1 is a side sectional view illustrating an uneven die used in the present invention.

[Explanation of symbols]

 1 Lower mold 2 Upper mold 3 Pore of lower mold 4 Pore of upper mold 5 Vacuum tank 5'Compressed air tank 6 Plastic sheet 7 Clamp part 7'Clamp part

Claims (4)

[Claims] 1. A mold in which fine holes are provided in respective concave portions of a concave-convex mold such that a pair of upper and lower concave and convex portions mesh with each other, and the fine holes are connected to a vacuum tank or a compressed air tank,
Place the primary or incompletely foamed plastic sheet heated to the heat distortion temperature of the work plastic or the heat distortion temperature + 60 ° C on the upper part of the lower mold, and then fit the upper mold to the irregularities of the lower mold. Put it, and the thickness of the primary foamed or incompletely foamed plastic sheet is 0.3 ~
Until the clearance of 2.5 mm is maintained, the temperature of the upper and lower molds is 30 to 30% higher than the surface temperature of the foamed plastic sheet.
Keeping at 90 ℃ low temperature, about 100g-20kg / 1cm ²
The pressure is applied for 0.3 to 10 seconds, and during this period, the pores of the mold are connected to a vacuum tank or a compressed air tank for suction or suction / pressurization or press / suction, and then the upper mold is pulled up. A method for producing a foamed plastic corrugated core, which comprises taking out a secondary foamed plastic that has been textured. 2. The method for producing a foamed plastic corrugated core according to claim 1, wherein the corrugated core is provided with a partitioning weir by providing a partitioning weir in the groove of the recess in at least one of the upper and lower molds. 3. A continuous product is obtained by providing a flat portion or a corrugated portion on at least one of the outer sides of a die end portion, and continuously forming the clamp portion produced at the next processing at the next processing. 2. The method for producing a foamed plastic corrugated core according to 2. 4. The foamed plastic corrugated core manufacturing according to claim 3, wherein the temperature of the mold end portion and the peripheral portion (clamp portion) is further raised above the temperature of the mold body central portion. Law.