JP2022105688A - Method for producing foam laminate sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foam sheet that does not easily cause structural unevenness including pinholes.

SOLUTION: A method for producing a foam laminate sheet includes a lamination process to form a laminate by laminating multiple foam sheets, and a thermocompression bonding process of thermocompression bonding the laminate at a temperature not lower than a softening point and not higher than a melting point of the plurality of foam sheets constituting the laminate.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a method for producing a foam laminated sheet.

The foam (foam sheet) molded into a sheet shape usually has high cushioning property and good followability to unevenness. Furthermore, the foamed sheet not only enhances airtightness by adopting a so-called closed cell foam structure (improves water permeability and breathability by adopting a so-called open cell foam structure), but also has a predetermined additive. It is possible to improve conductivity, thermal conductivity, hydrophilicity, etc. by adding the above. As described above, the foamed sheet is a functional material capable of imparting various properties depending on the situation in which it is used and the intended use.

Here, in the foamed sheet, a skin layer (also referred to as an epidermis layer) without bubbles is usually formed on the surfaces on both sides of the sheet in the process of forming the composition as a raw material of the foam into a sheet. Since this skin layer has a high density, it is hard and causes a decrease in cushioning property and followability to fine irregularities. Therefore, in order to ensure cushioning and followability to unevenness, the skin layer may be divided and removed by splitting or the like, and only the core portion having no skin layer may be used as the foam sheet.

In Patent Document 1, the constituent material of the cushion material before foaming and the constituent material of the foamed resin base material before foaming are extruded and laminated at the same time, and the cushion material and the foamed resin base material are combined at the same time as or immediately after the extrusion molding. By foaming at the same time, while having a sufficient foaming ratio, deformation such as warping, bending, and twisting does not occur, no special effective material is required, and the cushioning material is efficiently laminated. A method for producing a foamed resin molded body that can be performed is disclosed.

JP 2009-56650

However, when the foamed sheet is molded according to the method of Patent Document 1, structural unevenness including the presence of pinholes (air bubbles existing in the thickness direction of the sheet) occurs, and not only the appearance but also the mechanical There were also problems with the nature.

Therefore, it is an object of the present invention to provide a foamed sheet in which structural unevenness including pinholes is unlikely to occur.

The present inventors have conducted diligent research based on the above-mentioned problems, and have found that the above-mentioned problems can be solved by subjecting a plurality of foam sheets to a specific treatment to obtain a foam laminated sheet, and have completed the present invention. .. That is, the present invention is as follows.

The present invention (1) is
It is a method of manufacturing a foam laminated sheet.
A laminating process of laminating multiple foam sheets to form a laminated body,
A thermocompression bonding step of thermocompression bonding the laminate at a temperature equal to or higher than the softening point of the plurality of foam sheets constituting the laminate and lower than the melting point.
It is a method of manufacturing a foam laminated sheet including.
The present invention (2) is
The manufacturing method according to the invention (1), wherein one or both of the foamed sheets do not have a skin layer on the contact surface of each pair of the plurality of foamed sheets constituting the laminated body.
The present invention (3) is
The invention (1), wherein a part or all of the plurality of foam sheets constituting the laminate is obtained by dividing the raw foam sheet into a plurality of foam sheet divided products in the thickness direction. ) Or (2).
The present invention (4) is
The foamed sheet raw fabric is a sheet obtained by foaming a resin composition containing at least a resin.
An impregnation step of impregnating the melted resin composition with the substance in the supercritical state or the subcritical state under the condition that the supercritical state or the subcritical state of the substance which is a gas at normal temperature and pressure is maintained.
Obtained by a foamed sheet manufacturing step including a foaming step of foaming the resin composition by arranging the resin composition impregnated with the substance under conditions in which the supercritical state or the subcritical state of the substance is not maintained. This is the manufacturing method of the above-mentioned invention (3).
The present invention (5)
The inventions (1) to (5), wherein bubbles having a bubble diameter of 10 to 200 μm are present in an amount of 100 (pieces / mm ² ) or more and less than 1000 (pieces / mm ² ) on the surface of the foam sheet having no skin layer. It is one of the manufacturing methods.

According to the present invention, it is possible to provide a foamed sheet in which structural unevenness including pinholes is unlikely to occur.

Further, according to the present invention, it is possible to improve the degree of freedom in designing such as followability and mechanical properties even under the condition that the thickness of the foam is restricted.

FIG. 1 is a schematic view of a sheet laminating method and a thermocompression bonding method in Examples. FIG. 2 is a schematic view showing a method for measuring 180 ° peel strength in Examples.

Hereinafter, the method for producing a foam laminated sheet according to the present invention will be described in detail, but the present invention is not limited thereto.

<<< Manufacturing method of foam laminated sheet >>>
The method for producing a foam laminated sheet according to the present invention includes a laminating step of laminating a plurality of foam sheets to form a laminated body, and a temperature at a temperature equal to or higher than the softening point of the plurality of foam sheets constituting the laminated body and lower than the melting point. It includes at least a heat crimping step of heat crimping the laminate. Further, it is preferable that a part or all of the plurality of foamed sheets constituting the laminated body is obtained by the foamed sheet manufacturing process, and also by the foamed sheet dividing step of dividing the foam sheet raw fabric in the thickness direction. It is preferably obtained. The method for producing a foam laminated sheet according to the present invention may include other steps, if necessary.

Here, the foamed sheet refers to a foamed structure molded into a sheet shape. The so-called sheet refers to one sheet such as thin paper as the smallest unit. It also includes large tarpaulins used for mattresses and rain shelters. In the foamed sheet of the present invention, the manufacturing method is not limited, and the ones manufactured one by one by batch processing with a mold may be in the shape of a long piece of cloth continuously manufactured by an extruder. ..

If the foam is molded into a sheet shape, the foam sheet (foam sheet raw fabric) used in the foam sheet division step, the foam sheet (foam sheet divided product) obtained by the foam sheet division step, and the foam. Laminated sheets and the like may be simply referred to as "foam sheets". Further, in some steps, the foamed sheet may be wound into a roll.

The foamed sheet in the present invention may be an open cell foam, but is preferably a closed cell foam. The closed-cell foam shown here does not mean only those in which all the bubbles are completely independent, but some of the bubbles may communicate with the adjacent bubbles, and the closed cells as a whole may be used. It is sufficient that each bubble is independent to the extent that it can be understood as a foam. Further, the foamed sheet as a closed cell foam may be further laminated with the foamed sheet as a closed cell foam as long as the effect of the present invention is not impaired.

Hereinafter, each of the above-mentioned steps will be described.

<< Foam sheet manufacturing process >>
The foamed sheet manufacturing process is a step of manufacturing a foamed sheet used in a laminating step or a foamed sheet dividing step, and a conventionally known foamed sheet manufacturing process can be applied. As the foam sheet manufacturing process, it is preferable to use a supercritical foaming method.

Hereinafter, the manufacturing process of the foamed sheet using the supercritical foaming method will be described, and then the manufacturing process of the foamed sheet using another foaming method will be described.

The foamed sheet obtained by the foamed sheet manufacturing process usually has skin layers on both surfaces. In the present invention, the skin layer means a layer having a relatively low foaming density, which is formed on the surface layer side in the thickness direction of the foamed sheet.

<Manufacturing process of foamed sheet using supercritical foaming method>
The manufacturing process of the foamed sheet using the supercritical foaming method includes a melting step of melting the resin composition and a condition in which the supercritical state or subcritical state of the substance which is a gas at normal temperature and pressure is maintained. The impregnation step of impregnating the molten resin composition with a substance in a supercritical state or a subcritical state (supercritical substance), and the condition that the resin composition impregnated with the supercritical substance is not maintained in the supercritical state of the supercritical substance. Includes a foaming step of foaming the resin composition by arranging. Further, a cooling step of cooling and crystallizing the resin composition in a molten state after foaming may be included. It should be noted that some or all of these steps may be executed at the same time.

(Melting process)
The melting step according to this embodiment is a step of melting the resin composition.

The resin composition preferably contains a thermoplastic polyolefin resin and a thermoplastic elastomer. In this case, the melting step is carried out under the condition that both the polyolefin resin and the thermoplastic elastomer are melted.

The thermoplastic polyolefin resin is not particularly limited, and may be a homopolymer of an olefin or a copolymer (random or block), and may be one kind or a combination of two or more kinds. For example, as the polyolefin, polyethylene, polypropylene, polybutene-1, ethylene-propylene copolymer, ethylene-α-olefin copolymer, polymethylpentene, cyclic olefin resin, and polyolefin in which a polar group is introduced (for example, ethylene). Vinyl acetate) may be used alone or in combination of two or more.

The thermoplastic elastomer is not particularly limited, and examples thereof include an olefin-based elastomer, a styrene-based thermoplastic elastomer, a urethane-based elastomer, and an ester-based elastomer.

Further, the resin composition may contain known components such as a foam nucleating agent and other thermoplastic polymers.

The blending amount of each component can be appropriately changed according to the intended use.

Since a substance in a supercritical state or a subcritical state is added and kneaded after the melting step, it is preferable that the temperature and pressure are such that the substance in the supercritical state is guaranteed even in the melting step.

(Immersion process)
The impregnation step is a step of impregnating the molten resin composition with the substance in the supercritical state or the subcritical state under the condition that the supercritical state or the subcritical state of the substance which is a gas at normal temperature and pressure is maintained. be.

In such a supercritical state or a subcritical state, the solubility in the molten resin is further increased, and the substance can be mixed at a high concentration. As a result, at the time of a sudden pressure drop, the generation of bubble nuclei increases due to the high concentration of the substance.

Furthermore, since the substance dissolved at the molecular level is vaporized, the bubbles formed are fine. As a result, the density of bubbles formed by the growth of the bubble nuclei becomes higher than in other states even if the porosity is the same.

Substances that are gaseous at room temperature include normal temperature (normal temperature specified by JISZ8703, specifically 5 ° C. or higher and 35 ° C. or lower), normal pressure (pressure when neither depressurization nor pressurization is performed, specifically, for example, 86 kPa). The gas is not particularly limited as long as it is a gas under a pressure of 106 kPa or less), but is preferably an inert gas, for example, carbon dioxide or nitrogen, and more preferably, the amount of impregnation into the polyolefin resin is increased. It is carbon dioxide that can be produced.

When carbon dioxide is selected as a substance that is a gas at normal temperature and pressure, the critical temperature of carbon dioxide is 31 ° C. and the critical pressure is 7.4 MPa. Therefore, when carbon dioxide is selected, the temperature is preferably in the range of 50 to 250 ° C, more preferably in the range of 90 to 230 ° C, and the pressure is in the range of 90 to 230 ° C. It is preferably in the range of about 8 to 40 MPa, and more preferably in the range of 10 to 30 MPa.

(Foaming process)
The foaming step according to this embodiment is a step of foaming a resin composition by arranging a resin composition impregnated with a substance that is a gas at normal temperature and pressure under conditions in which the supercritical state of the substance is not maintained. ..

For example, from an extruder having a high temperature (for example, about 155 to 180 ° C.) and high pressure inside, the resin composition impregnated with the substance is extruded through a mouthpiece {for example, continuously on a long sheet (for example, about 1 mm thick). It is carried out by pushing it out. That is, the resin composition is foamed while being formed into a sheet. As the base, a T die or a circular die can be used.

By dissolving a substance that is a gas at normal temperature and pressure in the resin composition under high pressure, bubble nuclei are uniformly dispersed at the molecular level, and then when the pressure is released under normal pressure, it foams from the inside and becomes fine. Bubbles are formed. That is, fine bubbles are formed by utilizing the difference in solubility under the pressure of the resin composition.

In the foaming step, it is only necessary to release the pressure, and the pressure applied to the resin composition is reduced to about atmospheric pressure simply by extruding the resin composition from the extruder, so that no decompression device is required. be.

More specifically, the method described in Patent 6025827 may be applied to the manufacturing process of the foamed sheet using such a supercritical foaming method.

<Manufacturing process of foamed sheet using other foaming methods>
As a step of manufacturing a foamed sheet using another foaming method, a known method can be applied. For example, a raw material preparation step which is a step of obtaining a liquid raw material mixture containing at least an aqueous liquid dispersion medium, a water dispersible resin, and a foaming agent, a foaming step of obtaining a foaming mixture for foaming the liquid raw material mixture, and foaming. Examples thereof include a manufacturing step including a sheet forming step of forming the mixture into a sheet and a drying step of evaporating the dispersion medium in the foamed mixture. It should be noted that some or all of these steps may be executed at the same time.

As the raw material of the liquid raw material mixture, a known one may be used and is not particularly limited.

The foaming means of the liquid raw material mixture is not particularly limited, and known foaming means may be used. Examples of such foaming means include a method of forming bubbles by blending a foaming agent that generates gas by a chemical reaction, a method of dissolving an appropriate gas in a liquid raw material mixture under high pressure, and then reducing the pressure. A method of forming bubbles by heating, a method of removing soluble substances mixed in the liquid raw material mixture and forming bubbles as voids, and mechanically stirring the liquid raw material mixture so that air or an appropriate gas is embraced. Method (mechanical floss) and the like can be mentioned.

The foaming conditions (temperature, time, etc.) in the foaming process can be appropriately changed according to the foaming means used, and the foaming density and the like can also be appropriately changed according to the physical properties of the foamed sheet required in the laminating process. be.

The means for molding the foamed mixture into a sheet is not particularly limited, and known means may be used. For example, coating using a doctor knife, a doctor roll, or the like can be mentioned. Further, the foamed mixture may be molded into a sheet by using an extruder or an injection molding machine.

The drying conditions in the drying step may be appropriately designed according to the conditions of the foaming mixture and the foaming method.

The foamed sheet obtained in the foamed sheet manufacturing step is subjected to a laminating step with or without a foamed sheet dividing step.

<< Foam sheet division process >>
The foam sheet dividing step is a step of dividing a foam sheet (foam sheet raw material) as a raw material in the thickness direction to obtain a plurality of foam sheet divided products.

More specifically, when the foamed sheet raw fabric is a foamed sheet having skin layers on both surfaces obtained by the foamed sheet manufacturing process described above, the foamed sheet dividing step has a skin layer on only one surface. A step of dividing into two foam sheets (a step of dividing the original foam sheet into two), or two foam sheets having a skin layer on only one surface and one or more foam sheets having no skin layer. It is a step of dividing (a step of dividing a foam sheet raw fabric into three or more).

The foamed sheet raw material used in the foamed sheet dividing step is not particularly limited and may be a general foamed sheet, but the foamed sheet obtained by the above-mentioned foamed sheet manufacturing process is preferable.

The method for dividing the foam sheet is not particularly limited, and for example, a band machine, a slicer, or the like can be used.

The thickness of the divided product of the foamed sheet is not particularly limited, and can be appropriately changed depending on the thickness of the foamed sheet required in the laminating step described later and the thickness of the original foamed sheet as the split source.

The foam sheet dividing step may be a step of removing only the skin layer on one side or both sides from the raw fabric of the foam sheet.

By executing such a foam sheet dividing step, it is possible to prepare a foam sheet having a predetermined thickness and density but having a skin layer on only one side, a foam sheet having no skin layer on both sides, and the like. can.

In the foam sheet dividing step, a foam thicker than a normal foam sheet may be used as the raw material. In this case, the number of divisions may be increased so that the foamed sheet divided product has a thickness to the extent required in the laminating step.

<< Laminating process >>
The laminating step is a step of laminating a plurality of foam sheets to form a laminated body.

Here, one or both of the contact surfaces of the layers of each pair of the plurality of foam sheets constituting the laminate (for example, the contact surface between the foam sheets arranged on the upper side and the foam sheets arranged on the lower side). It is preferable that the foam sheet does not have a skin layer. In other words, (1) each pair of foamed sheets, at least one of the foamed sheets is a foamed sheet having no skin layer on both sides, and (2) at least one of each pair of foamed sheets. It is preferable that the foamed sheet is a foamed sheet having a skin layer on only one surface, and the surface of the foamed sheet without a skin layer is laminated so as to be in contact with the other foamed sheet. With such a configuration, it is possible to prevent air bubbles from staying between the foam sheets in the thermocompression bonding step described later, and to improve moldability and interfacial adhesiveness. In order to further enhance such an effect, bubbles having a bubble diameter of 10 to 200 μm are present on the surface of the foam sheet without a skin layer of 100 (pieces / mm ² ) or more and less than 1000 (pieces / mm ² ). It is preferable to do so. Further, it is more preferable that bubbles of 50 to 150 μm are present.

In addition, in order to improve the followability, it is preferable to use a laminated body in which the skin layer is not arranged on the outermost layer.

The laminating method is not particularly limited, and another foamed sheet may be simply placed on one foamed sheet, or these may be temporarily fastened.

The number of foam sheets (number of layers) constituting the laminate is not particularly limited, and two foam sheets may be used, or three or more foam sheets may be used. By stacking three or more sheets, structural unevenness including pinholes is unlikely to occur, and the shielding property of light and the like is improved. Further, the densities of the foamed sheets to be laminated may be different from each other. In particular, in the case of a foam laminated sheet containing a foam sheet which is an open cell, the pressure loss can be controlled by forming a density gradient in the sheet thickness direction.

<< Thermocompression bonding process >>
The thermocompression bonding step is a step of performing thermocompression bonding of each foamed sheet at a temperature equal to or higher than the softening point of each foamed sheet constituting the laminated body obtained by the laminating step and lower than the melting point. By undergoing such a thermocompression bonding step, a plurality of foamed sheets can be integrated while maintaining the foamed structure of the foamed sheet to some extent.

The method of thermocompression bonding is not particularly limited, and a known method can be used, and examples thereof include a thermal roll. In the thermal roll method, two foam sheets are laminated and unwound, and the adhesive surfaces are brought into contact with each other and passed between two heated rollers to perform heat welding. In addition, for hot welding, a hot air welding method, a hot trowel welding method, a hot plate welding method, a high frequency welder welding method and the like can be used.

The conditions for thermocompression bonding may be controlled so that the temperature is at least on the contact surface between the foamed sheets so that the temperature is equal to or higher than the softening point of each foamed sheet and lower than the melting point (less than the melting point). More specifically, the heating temperature is preferably 5 to 40 ° C. higher than the softening point of each foamed sheet and 10 to 45 ° C. lower than the melting point of each foamed sheet.

Specifically, thermocompression bonding is preferably performed at a temperature of less than 160 ° C, more preferably 110 ° C or higher and 150 ° C or lower.

The heating time is not particularly limited, but is, for example, 0.085 to 0.15 seconds when crimping with a calendar roll.

The pressurizing conditions at the time of thermocompression bonding can be appropriately changed depending on the thickness of the foam sheet to be used and the thickness of the foam laminated sheet to be formed. For example, when thermocompression bonding is performed at a relatively weak pressure, a foam laminated sheet having a thickness that is not much different from the total thickness of each foam sheet can be obtained, and when thermocompression bonding is performed at a relatively strong pressure, it is optional. It can be a foam laminated sheet compressed to the thickness of. The pressurizing conditions can be changed by an appropriate method such as adjusting the distance between the rolls.

In this thermocompression bonding step, the interface between the foam sheets may or may not disappear.

The laminating step (molding of the laminated body) and the thermocompression bonding step may be performed in part or in whole at the same time. For example, the laminating step and the thermocompression bonding step may be executed at the same time by pulling out a plurality of roll-shaped foam sheets from the vertical direction and sandwiching them between the rolls so that they are pulled by the rolls. .. Further, by preheating at least the surface of the foamed sheet to maintain the temperature of the foamed sheet at a temperature equal to or higher than the softening point and lower than the melting point, and laminating and pressurizing the foamed sheets in that state, a part of the laminating step and the thermocompression bonding step. May be executed at the same time.

Further, the laminating step and the thermocompression bonding step may be performed a plurality of times each. For example, another foam sheet may be laminated on the foam laminated sheet formed through the laminating step and the thermocompression bonding step, and then thermocompression bonded to form a foam laminated sheet in which the number of layers is increased.

By executing the laminating process and the thermocompression bonding process as described above and laminating and integrating a plurality of foam sheets, the variation of each foam sheet is averaged and structural unevenness is less likely to occur. .. Specifically, even if a pinhole is present in a certain foamed sheet, another foamed sheet covers the pinhole, so that the occurrence of the pinhole can be remarkably suppressed.

Further, by executing the laminating step and the thermocompression bonding step as described above, the material, density, thickness, presence / absence of skin layer, and method of arranging the skin layer in the laminated body for each of the plurality of foam sheets (of each foam sheet). The parameters that can be set increase, such as whether to arrange the skin layer between the layers or to arrange the skin layer so as to be the outermost layer of the laminated body). Further, since these can be easily set, the degree of freedom regarding design such as followability and mechanical properties is improved.

<< Other processes >>
As other steps, as long as the effect of the present invention is not impaired, a processing step of shearing or drilling each sheet, cleaning or surface treatment of the surface of each sheet before, after or during each of the above-mentioned steps ( A processing step of performing corona discharge treatment, antistatic treatment, blocking prevention processing, etc., a storage step of holding each sheet in an appropriate environment (predetermined temperature, humidity, etc.), and the like may be executed.

<<< Applications of foam laminated sheet >>>
The application of the foam laminated sheet obtained by the above-mentioned manufacturing method is not particularly limited, and is suitable for shock absorbing sheets for electronic devices, thin-walled heat insulating sheets, waterproof gaskets, double-sided tape base materials, and the like. ..

<< First Example >>
<Example 1-1>
Pellets containing a polypropylene resin compound containing random polypropylene and an olefin resin containing low-density polyethylene were put into a tandem single-screw extruder and melted by the first extruder, and carbon dioxide was brought into a supercritical state. Was impregnated into the resin composition in which the pellets were melted, and sent to a second extruder.

A foam having a skin layer to which a shearing force is applied on the surface of the mouthpiece by discharging the molten resin composition impregnated with supercritical carbon dioxide from the mouthpiece of the second extruder and releasing the pressure at once. A sheet (foamed sheet raw fabric) was obtained. The base is a circular die, and the foam is continuously manufactured as a sheet and wound into a roll as a long foam sheet raw fabric.

Then, a cutting blade having a width larger than the width of the obtained foam sheet raw material was prepared. The roll-shaped foam sheet raw fabric is attached to the rewinding shaft, the cutting blade is applied between the skin layer and the foam intermediate layer of the foam sheet raw fabric, and the long sheet is applied to the skin layer and one side. It was separated into two long sheets (foamed sheet divided products) of the foamed intermediate layer in which the skin layer remained (skiving). Each long sheet after skiving was wound on a roll to obtain a long sheet in which the foamed intermediate layer was exposed on one side.

Then, the skiving process was performed again on the long sheet in which the skin layer was exposed on one side and the foaming intermediate layer was exposed on the other side, to obtain a slice sheet in which the foaming intermediate layer was exposed on both sides.

Depending on the presence or absence of skiving and the number of executions, foamed sheet raw fabric (foamed sheet with skin layers on both sides), single-sided sliced product (foamed sheet with skin layer on only one side), and double-sided sliced product (with skin layer). It is possible to prepare three types of foam sheets (not foam sheets).

In Example 1-1, two slice sheets (double-sided sliced products) having a thickness of 0.35 mm were produced from the raw foam sheet having an original thickness of 2.0 mm.

As shown in FIG. 1, the above two slice sheets were set as raw material foam sheets in a two-stage feeding machine. Next, in a state where the two raw material foam sheets were overlapped, they were passed between two calendar rolls (heating rolls) and thermocompression bonded to produce a foam laminated sheet. At this time, the surface temperature (machining temperature) of the calendar roll was 130 ° C., the sheet feeding speed was 5 m / min, and the gap between the rolls was 0.07 mm. The manufactured foam laminated sheet was wound into a roll by a winder.

The thickness of the foam laminated sheet after molding was 0.07 mm.

<Examples 1-2 to 1-6, Comparative Examples 1-1 to 1-3>
In the same manner as in Example 1-1, after setting the type of foam sheet used for thermocompression bonding (foam sheet raw fabric, single-sided slice product or double-sided slice product) and the thickness of each foam sheet, the foam sheet Thermocompression bonding was performed to obtain sheets according to Examples 1-2 to 1-6 and Comparative Examples 1-1 to 1-3.

Below, the type of foam sheet and the thickness of the foam sheet used for manufacturing the sheet according to each example and each comparative example, and the thickness of each example and each comparative example after thermocompression bonding are described. show. For single-sided sliced products, which side is used as the contact surface at the time of laminating is also shown. Table 1 shows the processing temperature and feed rate at the time of thermocompression bonding in the production of the foam laminated sheet according to each example and each comparative example.

(Example 1-1)
・ Foam sheet Double-sided sliced product (skinless) Thickness 0.35 mm
Double-sided slice product (skinless) Thickness 0.35 mm
・ Thickness after thermocompression bonding 0.07 mm
(Example 1-2)
・ Foam sheet Double-sided sliced product (skinless) Thickness 0.35 mm
Double-sided slice product (skinless) Thickness 0.35 mm
・ Thickness after thermocompression bonding 0.1 mm
(Example 1-3)
・ Foam sheet Double-sided sliced product (skinless) Thickness 0.4 mm
Double-sided slice product (skinless) Thickness 0.4 mm
・ Thickness after thermocompression bonding 0.15 mm
(Example 1-4)
・ Foam sheet Single-sided slice product (single-sided skin) Thickness 0.4 mm
Double-sided slice product (skinless) Thickness 0.8 mm
The skin surface of the single-sided sliced product was placed so as to be in contact with the double-sided sliced product.
・ Thickness after thermocompression bonding 0.15 mm
(Example 1-5)
・ Foam sheet Single-sided slice product (single-sided skin) Thickness 0.4 mm
Double-sided slice product (skinless) Thickness 0.5 mm
The skin surface of the single-sided sliced product was placed so as to be in contact with the double-sided sliced product.
・ Thickness after thermocompression bonding 0.2 mm
(Example 1-6)
・ Foam sheet Double-sided sliced product (skinless) Thickness 0.9 mm
Double-sided slice product (skinless) Thickness 0.9 mm
・ Thickness after thermocompression bonding 0.2 mm
(Comparative Example 1-1)
・ Foam sheet Double-sided sliced product (skinless) Thickness 0.6 mm
・ Thickness after thermocompression bonding 0.1 mm
(Comparative Example 1-2)
・ Foam sheet Double-sided sliced product (skinless) Thickness 0.8 mm
・ Thickness after thermocompression bonding 0.15 mm
(Comparative Example 1-3)
・ Foam sheet Double-sided sliced product (skinless) Thickness 0.8 mm
・ Thickness after thermocompression bonding 0.2 mm

Table 1 shows the thickness, density, bubble diameter, number of bubbles, and basis weight of each obtained sheet.

In addition, each foam sheet raw fabric was manufactured in the same manner as in Example 1-1 except that the thickness was adjusted.

Further, by changing the manufacturing conditions of the foamed sheet raw material and the skiving processing conditions, these foamed sheets were made to have a desired thickness.

The thickness of the sheet after thermocompression bonding was adjusted by changing the gap between the rollers at the most downstream.

<Evaluation>
(Appearance test)
The appearance of the sheet was observed in the range of 100 cm ² . The case where there is no pinhole / see-through is marked with ◯, and the case where there is pinhole / see-through is marked with ×. A hole having a diameter of 1 mm or more penetrating the sheet was used as a pinhole. A light table and a light table for visual inspection were used to determine the presence or absence of see-through. With the test piece placed on the table and the light source applied from the back surface, the leakage of light to the opposite surface was judged by visual judgment.

<< Second Example >>
<Examples 2-1 to 2-3, Reference examples 2-1 to 2-3>
Sheets according to Examples 2-1 to 2-3 and Reference Examples 2-1 to 2-3 were obtained in the same manner as in the first embodiment.

Below, the type of foam sheet and the thickness of the foam sheet used for manufacturing the sheet according to each Example and each reference example, and the thickness of the sheet according to each Example and each comparative example after thermocompression bonding are described. show. For single-sided sliced products, which side is used as the contact surface at the time of laminating is also shown. Table 2 shows the processing temperature and feed rate during thermocompression bonding in the production of the foam laminated sheet according to each example and each reference example.

(Example 2-1)
・ Foam sheet Foam sheet original fabric (double-sided skin) Thickness 1.6 mm
Double-sided slice product (skinless) Thickness 0.9 mm
・ Thickness after thermocompression bonding 0.2 mm
(Example 2-2)
・ Foam sheet Double-sided sliced product (single-sided skin) Thickness 1.3 mm
Double-sided slice product (single-sided skin) Thickness 1.3 mm
Arranged so that the skin surface comes to both outsides.
・ Thickness after thermocompression bonding 0.2 mm
(Example 2-3)
・ Foam sheet Double-sided sliced product (single-sided skin) Thickness 1.3 mm
Double-sided slice product (single-sided skin) Thickness 1.3 mm
Arranged so that the skin surface comes to both outsides.
・ Thickness after thermocompression bonding 0.25 mm
(Reference Example 2-1)
・ Foam sheet Foam sheet original fabric (double-sided skin) Thickness 1.6 mm, 1 sheet ・ Thickness after thermocompression bonding 0.15 mm
(Reference Example 2-2)
・ Foam sheet Foam sheet original fabric (double-sided skin) Thickness 1.6 mm, 1 sheet ・ Thickness after thermocompression bonding 0.2 mm
(Reference Example 2-3)
・ Foam sheet Foam sheet original fabric (double-sided skin) Thickness 1.6 mm, 1 sheet ・ Thickness after thermocompression bonding 0.25 mm

Table 2 shows the thickness, density, bubble diameter, number of bubbles, and basis weight of each obtained sheet.

<Evaluation>
(180 ° peel strength measurement method)
The 180 ° peel strength was measured under the following conditions. The evaluation results are shown in Table 2, and the outline of the measurement method is shown in FIG.
Double-sided adhesive tape (9671LE made by 3M, t50 μm) is attached to both sides of the sample.
A 25 μm-thick PET film is attached to one side as a backing material to prepare a test piece.
After punching the test piece to a width of 10 mm, it is attached to a stainless steel plate as an adherend.
(Adhesive surface length 60 mm) In that case, reciprocate once with a 2 kg roller in a room temperature environment to remove air from the adherend surface, and then leave it for 30 minutes to cure. In the test, a tensile tester (Autograph: manufactured by Shimadzu Corporation) was installed so that the peeling was 180 ° as shown in FIG. 1, and then the tensile strength was measured at a speed of 1,000 mm / min.
Specimen: 10 mm width Backing material: PET # 25
Crimping method: 2kg roller 1 reciprocation Crimping temperature: 23 ℃ / 50% RH
Curing conditions: 23 ° C / 50% RH x 30 min
Tensile speed: 1,000 mm / min
Tensile angle: 180 °
Measurement temperature: 23 ° C / 50% RH

No pinholes or see-through were confirmed in the sheets according to Examples 2-1 to 2-3.

Claims (5)

It is a method of manufacturing a foam laminated sheet.
A laminating process of laminating multiple foam sheets to form a laminated body,
A thermocompression bonding step of thermocompression bonding the laminate at a temperature equal to or higher than the softening point of the plurality of foam sheets constituting the laminate and lower than the melting point.
A method for manufacturing a foam laminated sheet, including. The manufacturing method according to claim 1, wherein one or both of the foamed sheets do not have a skin layer on the contact surface of each pair of the plurality of foamed sheets constituting the laminated body. 1. 2. The manufacturing method according to 2. The foamed sheet raw fabric is a sheet obtained by foaming a resin composition containing at least a resin.
An impregnation step of impregnating the melted resin composition with the substance in the supercritical state or the subcritical state under the condition that the supercritical state or the subcritical state of the substance which is a gas at normal temperature and pressure is maintained.
Obtained by a foam sheet manufacturing step including a foaming step of foaming the resin composition by arranging the resin composition impregnated with the substance under conditions in which the supercritical state or the subcritical state of the substance is not maintained. The manufacturing method according to claim 3, which has been obtained. The invention according to any one of claims 1 to 5, wherein bubbles having a bubble diameter of 10 to 200 μm are present in an amount of 100 (pieces / mm2) or more and less than 1000 (pieces / mm2) on the surface of the foam sheet without the skin layer. Production method.

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