JP2018020512A - Foam formation heat insulation sheet, molded article using the same, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam formation heat insulation sheet having vacuum foam formation cells obtained by vacuum suction of heated foam formation cells, a molded article thereof and improvement of the manufacturing method thereof.SOLUTION: There is provided a foam formation heat insulation sheet, which has a foam forming cells arranged on a low melting point foam formation resin laminated on a base paper by heating and vacuum suction, and consists of a high melting point synthesis resin film layer laminated on a surface of a non-foam formation side of the base paper, a low temperature synthetic resin film layer laminated on a surface of a foam formation side of the base paper and having foam formation cells, and a high melting synthetic resin film layer laminated on the low melting point synthetic resin film layer, covering the low melting point synthetic rein film layer and having no foam formation surface.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a foam heat insulating sheet, a molded product using the same, and an improvement of the manufacturing method thereof.

Conventionally, the present applicant has proposed prior inventions according to Japanese Patent Application Laid-Open Nos. 2004-58534 and 2004-58535 as a foam heat insulating sheet, a foam heat insulating container, and a manufacturing method thereof.
In the above-mentioned prior invention, a sheet obtained by laminating a synthetic resin film on a base paper is heated, and the synthetic resin film is foamed mainly using moisture contained in the base paper to form a foamed surface composed of foamed cell groups. Foam height of the foam cell by vacuum suction with a mold that is sized to create a gap for sucking the foam cell between the foam surface and the suction surface provided on the mold. It has become a structure that has improved, and has given a corresponding result.
On the other hand, when the foaming height of the foam cell is increased, the cavity inside the foam is increased, and there is a problem that foaming is easily crushed.

JP 2004-58534 A JP 2004-58535 A

  The problem to be solved by the present invention is to provide a foam heat insulating sheet capable of obtaining a stable vacuum foam shape and a foam foam which is difficult to be crushed even when the foam height is increased by vacuum suction and a cavity inside the foam is enlarged. It is to provide a molded product and a manufacturing method thereof.

In order to solve the above problems, the present invention provides a foam heat insulating sheet according to claim 1,
In the foam insulation sheet having the foam cell group provided by heating and vacuum suction to the low melting point foamed resin laminated on the base paper,
A high melting point synthetic resin film layer laminated on the non-foamed side surface of the base paper, a low melting point synthetic resin film layer laminated on the foam side surface of the base paper and having a foam cell group, and the low melting point synthetic resin film layer It is characterized by comprising a high melting point synthetic resin film layer which is laminated on the low melting point synthetic resin film layer and does not have a foamed surface.
In invention of the manufacturing method of the foam heat insulation sheet of Claim 3,
Vacuum foamed cell group having a foaming height higher than that of the heated foamed cell group in a state in which the synthetic resin film laminated on the base paper is foamed by heating to form a heated foamed cell group and the heated foamed cell group is vacuum sucked by a mold In the manufacturing method of foam insulation sheet to form
A synthetic resin film laminated on a base paper is a high melting point synthetic resin film laminated on the non-foamed side surface of the base paper, a low melting point synthetic resin film laminated on the foam side of the base paper, and the low melting point synthetic resin film It consists of a high melting point synthetic resin film layer laminated on the outermost side of the foam side surface,
The low melting point synthetic resin film layer is heated above the melting point temperature of the low melting point synthetic resin film and below the melting point temperature of the high melting point synthetic resin film to form a foamed cell group on the low melting point synthetic resin film,
A vacuum foamed cell group covered with a high melting point synthetic resin film is formed by vacuum suction of a heated foam cell group formed on the low melting point synthetic resin film with the mold through the high melting point synthetic resin film. Features.

In the foam heat insulating sheet of the present invention, a molded product using the same, and its production method, the low melting point synthetic resin film layer is heated at the melting temperature of the low melting point synthetic resin film layer to evaporate moisture contained in the base paper and foam the low melting point synthetic resin film. Vacuum foamed cell covered with a high melting point synthetic resin film by sucking the heated foamed cell group in a vacuum state through a high melting point synthetic resin film layer in a vacuum state Since it forms into a group, foaming is hard to be crushed and a stable vacuum foaming shape can be formed.
That is, since the high melting point synthetic resin film layer, which is a non-foamed layer, receives the vacuum pressure during vacuum foaming as compared with the conventional configuration, the shape of the vacuum foamed cell is not easily crushed.
Therefore, the tactile sensation feels firmer than before.
In addition, the appearance is higher than the conventional matte tone and becomes a mirror tone, and the visibility is also high, and a shaping effect superior to the conventional one can be obtained.

(A) is sectional drawing of the laminated base paper of a present Example, (b) is sectional drawing of the laminated base paper of a single layer structure. FIG. 2 is a schematic diagram showing the direction of water vaporization during heating and foaming in this example, and FIG. 2B is a schematic diagram showing the direction of water vaporization of the single-layer structure. It is a schematic diagram at the time of vacuum foaming the heating foam cell of a present Example with a vacuum metal mold | die. (A) The schematic diagram of the state which received the vacuum pressure of the vacuum foaming cell of a present Example, (b) is the schematic diagram of the state which received the vacuum pressure of the vacuum foaming cell of the same single layer structure. It is a graph which shows the relationship between a foaming height of a present Example and the heating foam cell of a single layer structure, and the number of foam cells. It is a graph which shows the relationship between the foaming height of a present Example, the heating foam cell of a single layer structure, and a vacuum foam cell, and the number of foam cells. (A) shows the structure of this example, and (b) shows a schematic diagram of a single layer structure.

A preferred embodiment of the present invention will be described below in comparison with a conventional structure (hereinafter also referred to as “single layer structure”).
Moreover, a synthetic resin film shows a polyethylene film as an example.
Here, in this specification, for convenience of explanation, a foam cell formed by heating is referred to as a heated foam cell, and a foam cell obtained by vacuum suction of the heated foam cell is distinguished as a vacuum foam cell.

  In this embodiment, as shown in FIG. 1 (a), a high melting point polyethylene film 2 is laminated on the back surface (the surface that is not foamed) of the base paper 1, and the low melting point polyethylene film 3 is formed on the surface (the surface that is foamed) of the base paper 1. A laminated base paper 10 in which a high melting point polyethylene film 4 is laminated on the low melting point polyethylene film 3 is used.

In this example, as an example, the high melting point polyethylene film 2 on the back side was 15 μm, the low melting point polyethylene film 3 on the front side was 50 μm, and the high melting point polyethylene film 4 was 15 μm.
In the present invention, the thickness of the film is not limited to the above numerical value, the thickness of the low melting point polyethylene film 3 is a thickness capable of forming a heated foam cell by heating, and the thickness of the high melting point polyethylene film 4 is low. Any thickness that does not greatly hinder the formation of the heat-foamed cell of the melting point polyethylene film 3 may be used.

In this example, as an example, the high melting point polyethylene film 4 on the back side has a melting point of 131 ° C. and MFR 6.5 g / 10 min, the low melting point polyethylene film 3 on the front side has a melting point of 106 ° C. and MFR 14 g / min, and the high melting point on the front side. The polyethylene film 4 has a physical property with a melting point of 120 ° C. and an MFR of 6.15 g / 10 min.
The moisture content of the base paper 1 was 7%.
Of course, the above numerical values are not limited by the present invention.

  In addition, as shown in FIG. 1B, a laminated base paper 10 ′ having a single-layer structure to be compared is obtained by laminating a high-melting point polyethylene film 2 ′ on the back surface (the surface not foamed) of the base paper 1 ′, and the surface of the base paper 1 ′. The (foamed surface) has a structure in which a low melting point polyethylene film 3 ′ is laminated, and a polyethylene film having the same physical properties as in this example was used.

[Pre-foaming process]
First, the laminated base paper 10, 10 ′ is heated at the melting temperature of the low melting point polyethylene film 3.
Here, although heating was performed at 120 ° C. for 90 seconds as heating conditions, heating conditions corresponding to the physical properties and thickness of the synthetic resin film can be used in the present invention.

In the laminated base paper 10, due to the effect of laminating the high melting point polyethylene film 4 on the low melting point polyethylene film 3, the direction of moisture evaporation from the base paper 1 ′ is only in the height direction as in the conventional laminated base paper 10 ′. On the other hand (see FIG. 2 (b)), the direction of moisture vaporization from the base paper 1 becomes the height direction and the lateral direction, and foaming is suppressed as shown in FIG. 2 (a).
Thus, as shown in FIG. 5, the heated foam cell group 5 (indicated by black circles) formed by heating is a conventional single-layered heated foam cell group 5 ′ (indicated by black triangles in the figure). ), The number of foam cells is small, the foam height is low, and the foam shape is slightly coarser than the conventional fine foam shape.
Here, the number of foam cells was counted by observing the cross section of the foam cell group on the screen of the X-ray / CT apparatus, and counting the foam cells within 1 mm 2 square on the screen.

[Vacuum foaming]
Secondly, the laminate base paper 10, 10 ′ on which the heated foam cell groups 5, 5 ′ are formed is set in a vacuum mold (not shown) (see FIG. 3).
The size of the vacuum mold is set so that a gap for sucking the heated foam cell is formed between the foam surface of the heated foam cell group 5, 5 ′ and the suction surface provided in the mold. At this time, if the surface on which the base paper is not sucked is pressed at a place other than the suction surface of the mold, the base paper is not displaced during suction, and a beautiful suction process can be performed.

In the laminated base paper 10, the heated foam cell group 5 is sucked through the high melting point polyethylene film 4 by vacuum suction using the vacuum mold to form a vacuum foam cell 6 having a high foam height.
Here, the vacuum conditions are suction pressure: −40 kPa and suction time 5 seconds, but in the present invention, the vacuum conditions can be appropriately changed according to the thickness and physical properties of the synthetic resin film.

In the laminated base paper 10 ′ having a single layer structure, the vacuum cell from the vacuum mold is directly received by the heated foam cell group 5 ′, so that the vacuum foam cell 6 ′ is easily broken, and the vacuum foam cell 6 The reproducibility was low, such as “has popped off” (see FIG. 4B).
On the other hand, in the laminated base paper 10 of the present embodiment, the vacuum pressure is received by the high melting point polyethylene film layer 4 which is a non-foamed layer, so that the column of the sucked vacuum foam cell 6 is difficult to break, and reproducibility. (See FIG. 4A).
That is, as shown in FIG. 6, the vacuum foam cell 6 (indicated by a white circle in the figure) formed by vacuum suction of the present embodiment is a vacuum foam cell 6 ′ having a conventional single layer structure (in the figure, a white triangle). The number of foam cells that have not collapsed increases. Although the foam height is lower than that of the single layer structure, the difference in foam height in the vacuum foam cell group is smaller than the difference in foam height in the heated foam cell group.

[Shaping effect]
In the conventional single-layer structure, as described above, as shown in FIG. 7 (b) 13, the column of the vacuum foam cell 6 ′ is easily cut or crushed, the touch feeling is soft, the glossiness of the appearance is low, or the matte tone. It was.
On the other hand, in this embodiment, as shown in FIG. 7 (a) 3, the tactile sensation of the vacuum foamed cell 6 is hard to be crushed and has a hard tactile sensation and a high glossiness of the appearance, but becomes a mirror tone (FIG. 7). reference).

[Compression test]
Calculate the foam shape memory ratio of the vacuum foam cell 6 when it is compressed for 20 seconds with a load of 1400 N using a strograph, compare the conventional single layer structure with this example, and compare the tactile difference did.
Here, foam shape memory ratio (%) = foaming height after compression / foaming height before compression × 100.
It was confirmed that the foam shape memory ratio was 63% in the single layer structure, and the foam shape memory ratio was 99% in the present invention.

[Appearance Evaluation (Glossiness Measurement)]
The specular gloss is indicated by the reflectance of light from the light source.
The measuring method was measured according to JIS Z 8741-1997.
Glossiness measurement results are the result of vacuum foaming using the same mold,
(1) Vacuum mold 1 (rhombus uneven pattern)
Single layer structure 9.1%, Example 15.0%
(2) Vacuum mold 2 (grating pattern)
Single layer structure 5.2%, Example 9.2%
(3) Vacuum mold 32 (triangular uneven pattern)
Single layer structure 4.6%, Example 4.8%
From the above, it was confirmed that the glossiness of the present example having a multilayer structure was higher than that of the single layer structure in any case.

[Evaluation of appearance (luminance measurement)]
The luminance difference was measured by the luminance of the vacuum foamed portion (convex portion) −the non-foamed portion (concave portion). The method of measuring the luminance was to first maintain the interior at a constant illuminance, and the sample to be measured was placed in a dome illumination provided with a hole for photographing with a camera at the top. Next, the illuminance in the dome illumination is set to 1100 lux, a sample is photographed with a camera from the photographing hole, and the brightness of the vacuum foaming part (convex part) and the non-foaming part (concave part) is analyzed using analysis software. Each was measured.
(1) Vacuum mold 1 (rhombus uneven pattern)
Single layer structure 89.0 cd / m 2 Example 96.9 cd / m 2
(2) Vacuum mold 2 (grating pattern)
Single-layer structure 65.2 cd / m 2 Example 96.9 cd / m 2
From the above, it was confirmed that, in any case, the present example having a multilayer structure had a larger luminance difference and higher visibility than the single layer structure.

As described above, in this embodiment, since the high melting point synthetic resin film layer receives the suction pressure during vacuum foaming as compared with the conventional configuration, the vacuum foam cell 6 formed on the low melting point polyethylene film has strength and shape. Since it is hard to collapse and has a hard touch, it has excellent heat insulation performance.
In addition, the appearance is a mirror-like with high glossiness, high visibility, and a shaping effect and design effect superior to those of the prior art can be obtained.

In the present invention, the laminated base paper may be pre-foamed and vacuum foamed as a blank.
In this case, cups, containers, and other molded products may be molded using a foamed blank.

Alternatively, the laminated base paper may be pre-foamed and vacuum foamed after being molded into a paper container such as a cup or cup, or other molded product.
Moreover, although the polyethylene film was mentioned as an example of the synthetic resin film in the said Example, you may use the other synthetic resin film which can be foamed.
In addition, it goes without saying that various design changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Base paper 1 'Base paper of conventional structure 2 High melting point polyethylene film of back side 2' High melting point polyethylene film of back side of conventional structure 3 Low melting point polyethylene film of surface side 3 'Low melting point polyethylene film of surface side 4 High side of high melting point Melting point polyethylene film 5 Heated foam cell group 5 'Heated foam cell group of conventional structure 6 Vacuum foamed cell 6' Vacuum foamed cell 10 of conventional structure 10, 10 'Laminated base paper

Claims (5)

In the foam insulation sheet having the foam cell group provided by heating and vacuum suction to the low melting point foamed resin laminated on the base paper,
A high melting point synthetic resin film layer laminated on the non-foamed side surface of the base paper, a low melting point synthetic resin film layer laminated on the foam side surface of the base paper and having a foam cell group, and the low melting point synthetic resin film layer A foam insulation sheet characterized by comprising a high melting point synthetic resin film layer laminated on top and covering the low melting point synthetic resin film layer and having no foamed surface.   A molded product having a foam insulation part, wherein the foam insulation sheet according to claim 1 is used for all or at least a part of the molded product. Vacuum foamed cell group having a foaming height higher than that of the heated foamed cell group in a state in which the synthetic resin film laminated on the base paper is foamed by heating to form a heated foamed cell group and the heated foamed cell group is vacuum sucked by a mold In the manufacturing method of foam insulation sheet to form
A synthetic resin film laminated on a base paper is a high melting point synthetic resin film laminated on the non-foamed side surface of the base paper, a low melting point synthetic resin film laminated on the foam side of the base paper, and the low melting point synthetic resin film It consists of a high melting point synthetic resin film layer laminated on the outermost side of the foam side surface,
The low melting point synthetic resin film layer is heated above the melting point temperature of the low melting point synthetic resin film and below the melting point temperature of the high melting point synthetic resin film to form a foamed cell group on the low melting point synthetic resin film,
A vacuum foamed cell group covered with a high melting point synthetic resin film is formed by vacuum suction of a heated foam cell group formed on the low melting point synthetic resin film with the mold through the high melting point synthetic resin film. The manufacturing method of the characteristic foam insulation sheet.   A process of forming a heat-foamed cell group by heating on the low-melting-point synthetic resin film and then forming the vacuum foamed cell group by sucking the heat-foamed cell group is performed in a blank stage before molding as a molded product. The manufacturing method of the foam heat insulation sheet of Claim 3 characterized by the above-mentioned.   The process of forming a heated foam cell group by heating on the low melting point synthetic resin film and then forming the vacuum foam cell group by sucking the heated foam cell group is in the middle of molding as a molded product, or after molding The process for producing a foam heat insulating sheet according to claim 3, wherein the process is carried out in the following step.

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