JP2002361727A - Method and apparatus for processing plastic foam sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method in which a beautiful V-shaped channel is implemented in high productivity in processing for molding the V-shaped channel when hinge structure is given to a thick foam sheet, and to provide an apparatus for the method. SOLUTION: Implemented are a process (1) in which a molding bar having a wedge-shaped cross section is laid on the tip of a heating bar to overlap each other (Fig. 3); a process (2) in which the heat of the heating bar is applied to the foam sheet through the molding bar, and the V-shaped channel is formed by pressurization (Fig. 4); a process (3) in which, after the V-shaped channel is formed, the heating bar is removed to stop heating with the molding bar left (Fig. 5); and a process (4) in which, after a part of the V-shaped channel of the foamed sheet is cooled and solidified, the molding bar is separated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for forming V-grooves in plastic foam sheets, especially products made of thick sheets, and also to an apparatus used for carrying out the method.

[0002]

2. Description of the Related Art A plastic film melt-extruded from a T-die is formed by a roll type vacuum forming means to form a cap film having a number of caps, and a flat plastic film called a back film is formed on the bottom of the cap film. A molded product provided with a number of closed air chambers by attaching a film is used as a "plastic foam sheet" (hereinafter abbreviated as "bubble sheet") in a wide range of fields including buffer packaging materials. Have been. In addition, by connecting the top of the cap, another flat film called a liner film is attached,
Some products have a three-layer structure.

A product called "board" having the same structure as the foam sheet but having a very thick material is used as a building material or an interior material of an automobile. Because the material is thick and has considerable rigidity and strength, it must be heated and crushed to provide a groove having a V-shaped cross-section in order to bend even during processing. FIG. 1 shows a cross section of a V-shaped groove. In the figure, reference numeral (1) denotes a bubble sheet, (11) denotes a cap sheet, (12) denotes a back sheet, (13) denotes a liner sheet, and (2) denotes a V-shaped groove.

[0004] The skill of the processing for forming the V-shaped groove is important especially in the case of a "hinge" structure which can be repeatedly bent at a bent portion. In many cases, the end face of the foam sheet is also closed. In this case, the foam sheet is also crushed to form a V-shaped groove, and decorative trimming is performed along the bottom of the groove.

In any case, the process of forming a V-shaped groove in this kind of bubble sheet is performed by heating and pressing the tip with a wedge-shaped seal bar. As a result, the air inside the bubbles expands,
There is a problem that air bubbles swell after releasing the seal bar. Then, unsightly irregularities are generated on both sides of the V-shaped groove, and the commercial value is spoiled. FIG. 2 shows a cross section of such a failed V-shaped groove. Of course, the same problem exists with respect to the closing process of the end face.

To prevent this, after forming a V-shaped groove by heating and pressing with a seal bar, turning off the power, leaving the seal bar in that position, cooling both the seal bar and the bubble sheet, The seal bar may be removed after the deformation is no longer occurring, but such measures severely reduce productivity and are not viable in industrial practice.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem associated with the processing of forming a V-shaped groove in a thick foam sheet, and to form a beautiful V-shaped groove without irregularities.
Moreover, it is to provide a processing method with high productivity. It is also an object of the present invention to provide an apparatus for performing the method.

[0008]

According to the present invention, there is provided a method of forming a bubble sheet, comprising the steps of forming a V-shaped groove in a bubble sheet as shown in FIG. 1) Laminate a molding bar having a wedge-shaped cross section on the tip of the heating bar (FIG. 3A). 2) Apply heat from the heating bar to the bubble sheet through the molding bar, and pressurize to V. Forming a V-shaped groove (FIG. 3B); 3) after the V-shaped groove is formed, removing the heating bar while leaving the forming bar to stop heating (FIG. 3C); and 4) V of the bubble sheet After the groove is cooled and solidified, the forming bar is released (FIG. 3D).

An apparatus for forming a V-shaped groove in the bubble sheet of the present invention for carrying out this processing method is shown in FIG.
It consists of the following components. A) A sealing table (3) on which a plastic foam sheet (1) to be processed is placed, and means for carrying the plastic foam sheet into and out of it (not shown) B) Heating bar (4) and close contact with it Press the heating bar and the molding bar against the molding bar (5) having a wedge-shaped cross section, and C) the plastic foam sheet on the table to cause plastic deformation. Control means (not shown) for releasing the heating bar first, and then releasing the forming bar when the deformed portion of the plastic foam sheet has cooled and solidified.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The shape of the forming bar used in the present invention may be any as long as the tip, that is, the side pressed toward the bubble sheet, conforms to the shape of the V-shaped groove to be formed. The shape of the contacting surface is arbitrary as long as the adhesion between them is ensured. However, the conventional seal bar performs heating and molding all at once, and since the tip is already in the shape of a V-shaped groove, it is convenient to use it, and To ensure uniformity,
As shown in the figure, it is optimal to use the molded sheet as a plate having an L-shaped cross-section and to be stacked on the heating bar simply because the cross-section of the molded sheet is preferably substantially the same throughout. It is.

The material of the forming bar is not limited as long as it has good heat conductivity. Copper is optimal from the viewpoint of heat conduction, but steel is preferable because a certain strength is required. From the viewpoint of reducing the heat capacity, a thinner one is advantageous. If necessary to secure rigidity, an appropriate rib or the like can be provided.

After the heating bar is overlaid on the forming bar and pressurized to form the V-shaped groove, the timing of releasing the heating bar is relatively easy to determine since the plastic deformation has completely occurred. Subsequently, the timing of releasing the forming bar is when the cooling and solidification of the deformed portion is substantially completed.
The best way to determine this is to measure the temperature of the forming bar and let it solidify when it falls below a certain limit, but usually empirically determine the time based on ambient conditions A simple means of doing is sufficient. In any case, by incorporating this sequence into the control means of the apparatus, the operation of forming the V-shaped groove can be automated.

The present invention is not limited to providing the hinge structure, which is the main purpose of forming the V-shaped groove, but can be applied to the closing process of the end face of the bubble sheet. In this operation, in addition to the above steps 1) to 4), as step 5), at the bottom of the V-shaped groove,
That is, makeup trimming may be performed along the portion where the bubble sheet is completely closed.

[0014]

EXAMPLE A V-shaped groove was formed on the following foam sheet. Cap sheet thickness: 450 μm Back sheet thickness: 350 μm Liner sheet thickness: 350 μm Cap diameter: 7.5 mm Height: 5 mm Pitch 10 mm staggered arrangement

A sealing bar having a tip angle of 90 degrees is used as a heating bar, and a forming bar having an L-shaped cross section and a thickness of 12 mm obtained by machining an equilateral angle steel made of structural steel is used as a heating bar. It was provided to be removable. This forming bar was pressed against the above-mentioned bubble sheet together with the heating bar whose temperature was raised to 230 ° C. by energizing, and heated and pressed so that the distance from the seal table, that is, the thickness of the hinge became 0.8 mm.

After the start of heating and pressurization (after the molding bar came into contact with the bubble sheet), plastic deformation was performed in about 3 seconds, and the heating bar was pulled up. Thereafter, the cooling and solidification of the deformed portion was completed in about 5 seconds, so the molding bar was also pulled up. Overall, one cycle lasted about 10 seconds. In this way,
A hinge with no cap swelling and a beautiful V-shaped groove was formed. When the same operation is performed using only the conventional seal bar and the power is turned off and cooling is waited, about 1 cycle per cycle
5 seconds.

[0017]

According to the processing method of the present invention, when providing a V-shaped groove in a thick foam sheet, heating and molding of the foam sheet are shared by different bars, respectively. Unlike the conventional technology, the structure that allows the cooling to be prevented is prevented from being hindered by the seal bar having a large heat capacity, thereby enabling rapid cooling, thereby reducing the appearance of the product due to expansion of bubbles. And can be performed with a short cycle time, that is, with high productivity. Therefore,

The processing apparatus of the present invention can be manufactured with only minor modifications to conventional equipment, and the increase in construction and operating costs is substantially equal to zero.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a thick bubble sheet provided with a V-shaped groove.

FIG. 2 is a cross-sectional view corresponding to FIG. 1, showing swelling of a bubble hitting a V-shaped groove.

FIG. 3 is a cross-sectional view showing the steps of the processing method of the present invention, wherein A is a stage in which a forming bar is superimposed on a heating bar and pressed against a bubble sheet, B is a stage during heating and pressing, and C is a heating bar. D indicates the stage at which the molding bar was released, and D indicates the stage at which the molding bar was released.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic foam sheet 11 Cap sheet 12 Back sheet 13 Liner sheet 2 V-shaped groove 3 Seal stand 4 Heating bar 5 Molding bar

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[Procedure amendment]

[Submission date] July 18, 2002 (2002.7.1)
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Processing method and processing apparatus for plastic foam sheet

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method for forming V-grooves in plastic foam sheets, especially products made of thick sheets, and also to an apparatus used for carrying out the method.

[0002]

2. Description of the Related Art A plastic film melt-extruded from a T-die is formed by a roll type vacuum forming means to form a cap film having a number of caps, and a flat plastic film called a back film is formed on the bottom of the cap film. A molded product provided with a number of closed air chambers by attaching a film is used as a "plastic foam sheet" (hereinafter abbreviated as "bubble sheet") in a wide range of fields including buffer packaging materials. Have been. In addition, by connecting the top of the cap, another flat film called a liner film is attached,
Some products have a three-layer structure.

A product called "board" having the same structure as the foam sheet but having a very thick material is used as a building material or an interior material of an automobile. Because the material is thick and has considerable rigidity and strength, it must be heated and crushed to provide a groove having a V-shaped cross-section in order to bend even during processing. FIG. 1 shows a cross section of a V-shaped groove. In the figure, reference numeral (1) denotes a bubble sheet, (11) denotes a cap sheet, (12) denotes a back sheet, (13) denotes a liner sheet, and (2) denotes a V-shaped groove.

[0004] The skill of the processing for forming the V-shaped groove is important especially in the case of a "hinge" structure which can be repeatedly bent at a bent portion. In many cases, the end face of the foam sheet is also closed. In this case, the foam sheet is also crushed to form a V-shaped groove, and decorative trimming is performed along the bottom of the groove.

In any case, the process of forming a V-shaped groove in this type of bubble sheet is performed by heating and pressing the tip with a wedge-shaped seal bar. The air inside the bubbles expands,
There is a problem that air bubbles swell after releasing the seal bar. Then, unsightly irregularities are generated on both sides of the V-shaped groove, and the commercial value is spoiled. FIG. 2 shows a cross section of such a failed V-shaped groove. Of course, the same problem exists with regard to the closing process of the end face.

To prevent this, after forming a V-shaped groove by heating and pressing with a seal bar, turning off the power, leaving the seal bar in that position, cooling both the seal bar and the bubble sheet, The seal bar may be removed after the deformation is no longer occurring, but such measures severely reduce productivity and are not viable in industrial practice.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem associated with the processing of forming a V-shaped groove in a thick foam sheet, and to form a beautiful V-shaped groove without irregularities.
Moreover, it is to provide a processing method with high productivity. It is also an object of the present invention to provide an apparatus for performing the method.

[0008]

A method of processing a bubble sheet according to the present invention for achieving the above object is a method for forming a V-shaped groove in a bubble sheet, as shown in FIGS.
It consists of the following steps. 1) A wedge-shaped forming bar is superimposed on the tip of the heating bar (FIG. 3). 2) Heat of the heating bar is applied to the bubble sheet through the forming bar and pressed to form a V-shaped groove. Forming (FIG. 4) 3) After the V-shaped groove is formed, remove the heating bar while leaving the forming bar to stop heating (FIG. 5), and 4) V-shaped groove portion of the bubble sheet After the material has cooled and solidified, the forming bar is released (Fig. 6).

An apparatus for forming a V-shaped groove in the bubble sheet of the present invention for carrying out this processing method is shown in FIG.
It consists of the following components. A) A sealing table (3) on which a plastic foam sheet (1) to be processed is placed, and means for carrying the plastic foam sheet into and out of it (not shown) B) Heating bar (4) and close contact with it Press the heating bar and the molding bar against the molding bar (5) having a wedge-shaped cross section, and C) the plastic foam sheet on the table to cause plastic deformation. Control means (not shown) for releasing the heating bar first, and then releasing the forming bar when the deformed portion of the plastic foam sheet has cooled and solidified.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The shape of the forming bar used in the present invention may be any as long as the tip, that is, the side pressed toward the bubble sheet, conforms to the shape of the V-shaped groove to be formed. The shape of the contacting surface is arbitrary as long as the adhesion between them is ensured. However, the conventional seal bar performs heating and molding all at once, and since the tip is already in the shape of a V-shaped groove, it is convenient to use it, and To ensure uniformity,
As shown in the figure, it is best to use the sheet as an L-shaped cross-section simply over the heating bar, for two reasons, since the cross-section of the molded sheet is preferably substantially the same thickness throughout. It is.

The material of the forming bar is not limited as long as it has good heat conductivity. Copper is optimal from the viewpoint of heat conduction, but steel is preferable because a certain strength is required. From the viewpoint of reducing the heat capacity, a thinner one is advantageous. If necessary to secure rigidity, an appropriate rib or the like can be provided.

After the heating bar is overlaid on the forming bar and pressurized to form the V-shaped groove, the timing of releasing the heating bar is relatively easy to determine since the plastic deformation has completely occurred. Subsequently, the timing of releasing the forming bar is when the cooling and solidification of the deformed portion is substantially completed.
The best way to determine this is to measure the temperature of the forming bar and let it solidify when it falls below a certain limit, but usually empirically determine the time based on ambient conditions A simple means of doing is sufficient. In any case, by incorporating this sequence into the control means of the apparatus, the operation of forming the V-shaped groove can be automated.

The present invention is not limited to providing the hinge structure, which is the main purpose of forming the V-shaped groove, but can be applied to the closing process of the end face of the bubble sheet. In this operation, in addition to the above steps 1) to 4), as step 5), at the bottom of the V-shaped groove,
That is, makeup trimming may be performed along the portion where the bubble sheet is completely closed.

[0014]

EXAMPLE A V-shaped groove was formed on the following foam sheet. Cap sheet thickness: 450 μm Back sheet thickness: 350 μm Liner sheet thickness: 350 μm Cap diameter: 7.5 mm Height: 5 mm Pitch 10 mm staggered arrangement

A sealing bar having an angle of 90 degrees at the tip is used as a heating bar, and a forming bar having an L-shaped cross section and a thickness of 12 mm obtained by machining an equilateral angle steel made of structural steel is used as a heating bar. It was provided to be removable. This forming bar was pressed against the above-mentioned bubble sheet together with the heating bar whose temperature was raised to 230 ° C. by energizing, and heated and pressed so that the distance from the seal table, that is, the thickness of the hinge became 0.8 mm.

After about 3 seconds from the start of heating and pressurization (after the molding bar came into contact with the bubble sheet), plastic deformation was performed. Thereafter, the cooling and solidification of the deformed portion was completed in about 5 seconds, so the molding bar was also pulled up. Overall, one cycle lasted about 10 seconds. In this way,
A hinge with no cap swelling and a beautiful V-shaped groove was formed. When the same operation is performed using only the conventional seal bar and the power is turned off and cooling is waited, about 1 cycle per cycle
5 seconds.

[0017]

According to the processing method of the present invention, when providing a V-shaped groove in a thick foam sheet, heating and molding of the foam sheet are shared by different bars, respectively. Unlike the conventional technology, the structure that allows the cooling to be prevented is prevented from being hindered by the seal bar having a large heat capacity, thereby enabling rapid cooling, thereby reducing the appearance of the product due to expansion of bubbles. And can be performed with a short cycle time, that is, with high productivity. Thus, the processing equipment of the present invention can be manufactured with only minor modifications to conventional equipment, and the increase in construction and operating costs is substantially equal to zero.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a thick bubble sheet provided with a V-shaped groove.

FIG. 2 is a cross-sectional view corresponding to FIG. 1, showing swelling of a bubble hitting a V-shaped groove.

FIG. 3 is a cross-sectional view for explaining the steps of the processing method of the present invention, showing a stage in which a forming bar is superimposed on a heating bar and a foam sheet is pressed.

FIG. 4 shows a stage during heating and pressing, following FIG. 3;

FIG. 5 shows a stage after the heating bar is detached, following FIG. 4;

FIG. 6 shows the stage after the forming bar is released, following FIG. 5;

[Description of Signs] 1 plastic foam sheet 11 cap sheet 12 back sheet 13 liner sheet 2 V-shaped groove 3 seal base 4 heating bar 5 forming bar

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6

Claims (2)

[Claims] 1. A processing method for forming a V-shaped groove in a plastic foam sheet, comprising the following various steps: 1) heating with a heating bar through a forming bar having a wedge-shaped cross section, and applying pressure. ) After the V-shaped groove has been formed, release the heating bar while leaving the molding bar to stop heating, and 3) Release the molding bar after the plastic foam sheet cools and solidifies. 2. A processing apparatus for forming a V-shaped groove in a plastic foam sheet comprising the following components: A) a table on which a plastic foam sheet to be processed is placed;
Means for transporting and removing the plastic foam sheet into and out of it; B) a heating bar and a molding bar having a wedge-shaped cross section, which is in close contact with it and transmitting heat and pressure; and C) a plastic foam sheet on the table. A control means for pressing the heating bar and the forming bar to plastically deform them, after the deformation, first releasing the heating bar, and then releasing the forming bar when the deformed portion of the plastic foam sheet is cooled and solidified.