JPH07241950A - Foam sheet and production thereof - Google Patents

Abstract

PURPOSE:To obtain a foam sheet having a fine uneven surface having depth by combining a foamed resin having a reticulated structure due to mechanical foaming and thermally expanded microbeads. CONSTITUTION:A foam sheet 11 is obtained by forming a resin layer on the surface of a base material 12 and thermally expanded balloons 15 of thermally foamable microbeads are scattered in the foamed resin layer along with foams due to mechanical foaming.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention can be applied to a wide variety of fields such as cosmetic sponges, light-shielding curtains, table cloths, wiping cloths, interior / exterior materials, suede paint, clothes, shoes and bags. And a manufacturing method thereof. More specifically, the present invention relates to a foam sheet having a fine and deep uneven surface formed by a combination of a foam resin having a network structure formed by mechanical foaming and heat-expanded micro beads, and a method for producing the foam sheet.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
The foam sheet has a foamed resin layer formed on the base material by mechanically foaming the foamed resin by mechanically mixing air into the resin to form a foamed resin, and applying the foamed resin layer to the base material. In some cases, gas is generated in the resin by a chemical reaction or heating to form a foamed resin, and the foamed resin layer is formed on the base material by applying the foamed resin to the base material.

All of the above-mentioned foam sheets have a structure in which cavities are scattered in the dry resin film, but the bubbles in the surface layer portion exposed to the outside air are broken during the drying process, and the surface of the foam sheet is broken. Had a dense film with little foaming, and its touch was shiny and cold with less unevenness like rubber.

A foam sheet using a heat-sensitive foaming agent such as microbeads has also been proposed. This foam sheet consists of a thermally expanded balloon of microbeads containing a liquid compound in a capsule (shell wall) made of a resin such as vinylidene chloride copolymer, which has excellent heat resistance, pressure resistance and stretch resistance. It had a resin layer that was evenly scattered from the inside to the surface, and the surface was uneven with depth. The one using a heat-sensitive foaming agent by utilizing this characteristic has been used for design prints such as clothing.

However, in this foam sheet,
Since the unevenness of the surface of the sheet was rough and the undulations were large, the unevenness of the surface was conspicuous, and the texture was hard and rugged.

The present invention has been made in view of such circumstances, and a combination of a foamed resin having a mesh structure by mechanical foaming and heat-expanded microbeads is used.
It is an object of the present invention to provide a foam sheet having a fine and deep uneven surface and a method for producing the foam sheet.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 is a foam sheet having a foamed resin layer formed on the surface of a base material, wherein the foamed resin layer comprises: The gist is a foam sheet characterized in that thermally expanded microballoons of thermally expanded balloons are scattered together with bubbles formed by mechanical expansion.

The gist of the invention according to claim 2 is a foam sheet characterized in that the resin is made of polyurethane and acrylic resin.

According to the third aspect of the invention, a foamed resin layer is formed on one surface of the release sheet, in which foamed mechanically expanded bubbles and thermally expanded balloons of heat-sensitive foamed micro beads are scattered, and the foamed resin layer is used as a base material. A gist of a foam sheet is characterized in that a fracture surface of a foamed resin layer formed by peeling the release sheet from an adhered foam sheet is used as a skin of the foam sheet.

A fourth aspect of the present invention is a method for producing a foam sheet in which a foamed resin layer is formed on a surface of a base material, wherein a resin containing heat-sensitive foamable micro beads is mechanically foamed,
The method for producing a foam sheet is characterized in that the foam resin is applied to the surface of the base material and heated to thermally expand the thermosensitive foam microbeads in the foam resin layer to form the foam resin layer. And

According to the fifth aspect of the invention, the resin is 1.5 to
The gist is a method for producing a foam sheet, which is characterized by mechanically foaming 6.0 times.

The present invention has as its gist a method for producing a foam sheet, characterized in that 1 to 40 parts by weight of heat-sensitive expandable microbeads are contained with respect to 100 parts by weight of resin.

According to a seventh aspect of the present invention, the heat-sensitive expandable microbeads have an unexpanded diameter of 10 to 20 μm to 30 to 80.
The gist is a method for producing a foam sheet, which is characterized by thermally expanding to a size of μm.

According to an eighth aspect of the present invention, a resin containing heat-sensitive expandable microbeads is mechanically foamed to be applied to one surface of a release sheet and heated to heat-expand the heat-sensitive expandable microbeads in the foamed resin layer. Form a foamed resin layer,
Then, the foamed resin layer is adhered to a base material, and thereafter, the release sheet is peeled off to form a foamed resin layer fractured surface on the base material surface layer. did.

The foam sheet of the present invention will be described in detail below. As shown in FIG. 1, the foam sheet 11 according to claim 1 has a foamed resin layer 13 formed on the surface of a base material 12. The base material may be any material as long as it can be coated, and is not limited by the material. Specifically, it is desirable to have a fine and deep uneven surface, for example, linings for clothes, shoes, bags, interior exterior materials, cosmetic sponges, blackout curtains, table cloths,
Examples of the base material include a wiping cloth or a material such as a non-woven fabric, a woven fabric, a knitted fabric, paper, a resin film, a sponge material, etc., which constitutes suede-like coating. The foamed resin layer is formed on the surface of this base material.

The foamed resin layer is a layer formed by mechanically foaming a synthetic resin. The type of resin constituting the foamed resin layer is not particularly limited, but thermoplastic resins such as acrylic resin, urethane resin, polyester resin, vinyl chloride resin, vinylidene chloride resin, and rubber latex can be handled in an aqueous system and It is preferable in that it is not necessary to use an organic solvent or the like harmful to the. Further, among the above-mentioned resins, those mainly composed of polyurethane resin and acrylic resin such as polyester polyurethane, polyether polyurethane, polycarbonate polyurethane, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate are resistant to discoloration and deterioration. Is excellent in
Moreover, it is more preferable because a surface layer having a soft texture can be formed. The type of resin constituting the foamed resin layer and the type of color pigment added thereto can be appropriately changed as necessary, whereby the feel and color of the surface of the foam sheet can be adjusted according to the application. can do.

In the foamed resin layer, heat-expanded balloons of heat-sensitive foamed micro beads are scattered together with bubbles generated by mechanical foaming. Thermosensitive foam microbeads are microspheres containing a liquid compound in microcapsules (shell walls) made of resin such as vinylidene chloride copolymer, which has excellent heat resistance, pressure resistance, and stretch resistance. The liquid composition in the capsule is vaporized and the capsule is in a state of thermal expansion.

FIG. 1 shows a state in which the foamed resin layer 13 formed on the surface of the substrate 12 in the foam sheet 11 of the present invention has the balloons 15 thermally expanded together with the bubbles 14 due to mechanical foaming. . As is apparent from FIG. 1, the surface of the foamed resin layer 13 has a varied surface structure in which thermally expanded balloons 15 are incorporated and scattered in a three-dimensional network structure formed by mechanical foaming. . Further, the balloon 15 in the surface layer portion of the foamed resin layer 13 has a part thereof protruding to the surface of the foamed resin layer 13, and the uneven surface thereof is larger than that of the conventional one in which the balloons are scattered in the resin not mechanically foamed. Since the unevenness is fine and the undulations are small, it creates a fine uneven and soft uneven surface. The foamed resin layer 13 has a structure in which the thermally expanded balloons 15 are taken in and scattered in a three-dimensional mesh structure formed by mechanical foaming, so that the foamed resin layer 13 is flexible and rich in impact resilience.

Although FIG. 1 shows that the foamed resin layer 13 is formed on one surface of the base material 12, this foamed sheet is used, for example, on both surfaces such as a cosmetic sponge or a wiping cloth. In the case of applying it to a use, it is preferable to use a base material having foamed resin layers formed on both sides.

In the foam sheet of the present invention, after the foamed resin layer is formed, the foamed resin layer is crushed to reduce the concavo-convex shape, and the appearance and texture of the concavo-convex surface can be adjusted.
Further, the designability can be improved by performing secondary processing such as embossing or printing.

Next, the foam sheet according to claim 3 will be described. The base material, the foamed resin layer, the resin, and the heat-sensitive foamable microbeads are the same as those described in the description of the foam sheet according to claim 3, and therefore the detailed description thereof is omitted here. In this foam sheet, as shown in FIG. 2, a release resin sheet 26 is formed on one surface thereof with a foamed resin layer 23 having bubbles 24 formed by mechanical foaming and thermally expanded balloons 25 of heat-sensitive expandable micro beads scattered therein. The resin layer 23 is a non-woven fabric, woven fabric, knitted fabric, paper, resin film,
A fractured surface of a foamed resin layer formed by peeling the release sheet 26 from a foamed sheet 21 adhered to a base material 22 such as a sponge material is used as a skin of the foamed sheet. (The cross-sectional structure is shown in FIG. 3).

The release sheet may be any sheet-like material such as non-woven fabric, woven fabric, knitted fabric, paper and the like, and its material, texture and the like can be variously selected for the purpose of changing the fracture surface shape of the foam layer. For example, when using a non-woven fabric as a release sheet,
When this was peeled off, as shown in FIG. 3, the peeling surface of the foamed resin layer was peeled off together with the release sheet as a part of the foamed resin layer that had entered between the constituent fibers of the non-woven fabric, resulting in irregular irregularities. It will present a cross section. Similarly, when a woven fabric, knitted fabric, or paper is used as the release sheet, a part of the foamed resin layer that has entered the gap between the constituent fibers of each material is peeled off together with the release sheet, and exhibits an irregular uneven fracture surface. Like Therefore, which release sheet is used depends on what purpose the foam sheet is specifically used for, its shape,
It may be appropriately determined in consideration of size and the like. Table 1 shows changes in the uneven shape of the fracture surface of the foamed resin layer depending on the type of the release sheet.

[0023]

[Table 1]

2 and 3, the foamed resin layer 23 is formed on one side of the base material 22, but this foamed sheet is used on both sides such as a sponge for makeup and a wiping cloth. In the case of applying to such an application, it is preferable to use one having a foamed resin layer adhered to both surfaces of a base material.

The foam sheet of the present invention can be further improved in design by subjecting it to secondary processing such as printing.

Next, a method of manufacturing the foam sheet according to claim 4 will be described. The base material, the foamed resin layer, the resin,
The heat-sensitive expandable microbeads are the same as those described in the first aspect of the invention, and therefore detailed description thereof will be omitted. This method is a method for producing a foam sheet having a foamed resin layer formed on the surface of a substrate such as a non-woven fabric, a woven fabric, a knitted fabric, paper, a resin film, and a sponge material. It comprises a step of mechanically foaming, a step of applying the foamed resin to the surface of the base material, and a step of heating the foamed resin to thermally expand the thermosensitive foam microbeads in the foamed resin layer.

First, the step of mechanically foaming a resin containing heat-sensitive expandable micro beads will be described. Acrylic resin, urethane resin, polyester resin, vinyl chloride resin, vinylidene chloride resin, rubber latex, etc., alone or in combination, is made into an emulsion form, and air is blown into this emulsion to mix and mechanically foam the resin. Let

A mechanical foaming aid such as ammonium stearate was added to the emulsion at a rate of 2-10% so that the resin was mechanically foamed 1.5 to 6.0 times. Incidentally, the range of this expansion ratio is sufficient strength such that the foamed resin layer does not break or crack during use,
It is a standard for providing the surface roughness and the porosity necessary for deriving the softness.

The emulsion contains heat-sensitive expandable micro beads. In this case, the heat-sensitive expandable microbeads are preferably added in a ratio of 1 to 40 parts by weight with respect to 100 parts by weight of the resin. This is because when the addition amount of the heat-sensitive expandable microbeads is less than 1 part by weight with respect to 100 parts by weight of the resin solid content, the heat-sensitive expandable microbeads scattered in the foamed resin layer become sparse, The effect due to the inclusion of, that is, the uneven shape of the foamed resin layer surface in the foamed sheet becomes more uneven, and a sufficient effect of being flexible and rich in impact resilience cannot be obtained. 40 parts by weight
This is because if the amount exceeds the weight part, the foamed resin layer becomes brittle and easily peels off from the base material during use. Table 2 shows changes in the depth of the uneven surface of the foamed resin layer depending on the amount of the heat-sensitive expandable microbeads added to the resin emulsion, and Table 3 shows the impact resilience of the foamed resin layer depending on the amount of the heat-sensitive expandable microbeads added to the resin emulsion. Showed the change.

[0030]

[Table 2] In Table 2, the apparent depth of the surface means the height of the heat-sensitive expandable microbeads protruding from the surface of the foamed resin layer shown in FIG.

[0031]

[Table 3] Incidentally, in Table 3, the recovery time is shown as an index representing the impact resilience of the foamed resin layer, and after applying a load of 5 kg / cm ² × 1 min to the foamed resin layer having a thickness of 1 mm, The time required for the thickness to recover to 90%.

Further, the addition amount of the heat-sensitive expandable microbeads not only affects the depth of the uneven surface of the foamed resin layer and the impact resilience, but also has a large effect on the porosity of the foamed resin layer, and the addition amount is appropriately changed. By doing so, the desired surface irregularity,
A foamed resin layer having impact resilience and porosity can be obtained.

Next, the heat-foamable microbeads are added and the resin mechanically foamed is applied to the substrate. The resin is applied to the base material by uniformly applying the mechanically foamed resin emulsion to the base material with an applicator such as a knife coater. The coating amount of the resin emulsion on the substrate is arbitrary, but when the texture and surface irregularity of the foam sheet are taken into consideration, the amount is 30
A coating amount of ˜300 g / m ² is preferred. The reason is that when the coating amount is less than 30 g / m ² , the thickness of the foamed resin layer becomes thinner and the unevenness formed on the surface becomes smaller.
On the other hand, when the coating amount exceeds 300 g / m ² , the thickness of the foamed resin layer becomes thicker and the irregularities formed on the surface become larger, but on the other hand, the texture becomes harder, and in terms of good feel and softness. There will be a problem that you cannot obtain a satisfactory product.

Next, by heating the foamed resin applied to the base material, the heat-sensitive foamed microbeads in the foamed resin layer are heated and expanded. If heating is performed at an excessively high temperature for a long time, the thermosensitive foam microbeads will burst or deform, and conversely, heating at an excessively low temperature will not cause thermal expansion of the thermosensitive foam microbeads to the intended extent. It turns out that. As a guide, the diameter of the heat-sensitive expandable microbeads when not expanded is 10 to 20 μm to 30 to 8
It is preferable that it expands to a size of 0 μm.

Next, a method of manufacturing the foam sheet according to claim 8 will be described. The base material, the foamed resin layer, the resin,
The heat-sensitive expandable microbeads are the same as those described in the first aspect of the invention, and therefore detailed description thereof will be omitted. In addition, in this method, a resin containing heat-sensitive expandable microbeads is mechanically foamed, applied to one surface of a release sheet, and heated to thermally expand the heat-sensitive expandable microbeads in the foamed resin layer to form a foamed resin layer. And the step of adhering a base material such as nonwoven fabric, woven fabric, knitted fabric, paper, resin film, sponge material to the foamed resin layer, and then peeling off the release sheet to form a broken surface of the foamed resin layer on the base material surface layer. Forming process.

First, acrylic resin, urethane resin, polyester resin, vinyl chloride resin, vinylidene chloride resin,
A resin such as rubber latex or a mixture thereof is made into an emulsion, and air is blown into the emulsion to mix the resin to mechanically foam the resin. Into this emulsion, heat-sensitive foaming micro beads are added together with a mechanical foaming aid such as ammonium stearate.

Next, this resin emulsion is used as a non-woven fabric,
Apply to one side of release sheet made of woven fabric, knitted fabric, paper, etc.,
The heat-sensitive expandable microbeads contained in the resin emulsion are thermally expanded by heating and drying. The foamed resin layer thus formed on the release sheet is adhered to a substrate such as a non-woven fabric, woven fabric, knitted fabric, paper, resin film, sponge material or the like. In this case, the adhesion may be such that the foamed resin layer and the substrate are not easily separated, and the adhesive used is not particularly limited.

After that, the release sheet is peeled off from the foamed resin layer, so that the surface of the foamed resin layer adhered to the substrate is
A specific fracture surface corresponding to the type of release sheet as shown in Table 1 is formed.

[0039]

【Example】

Example 1 100 parts by weight of a urethane resin (Daiichi Kogyo Seiyaku Co., Ltd., Superflex E2000) on one side of a non-woven fabric having a basis weight of 60 g / m ^{2 made} of polyester fiber, a foaming agent (Dainippon Ink and Chemicals Co., Ltd. Boncoat F- 1) 5 parts by weight of thermosensitive foaming microbeads (Matsumoto Yushi-Seiyaku Co., Ltd. Matsumoto Microspheres-F-30) 3 parts by weight of a urethane resin emulsion were mechanically foamed and coated with a knife coater at a coating amount of 150 g. / M ² and was dried by heating in a temperature atmosphere of 170 ° C. to obtain a foam sheet. When this foam sheet was applied as an exterior material for an interior, it became rich in design due to the beautiful suede-like matte surface of the foam sheet.

Example 2 100 parts by weight of urethane resin (Daiichi Kogyo Seiyaku Co., Ltd. Superflex E2000) and a foaming agent (Dainippon Ink and Chemicals Co., Ltd. Boncoat F-1) 5 parts by weight on the back surface of the plain woven fabric. Part, heat-sensitive expandable microbeads (Matsumoto Yushi-Seiyaku Co., Ltd. Matsumoto Microsphere-F-3
0) Mechanically foam an emulsion of urethane resin blended at a ratio of 3 parts by weight and apply a coating amount of 15 using a knife coater.
It was coated so as to be 0 g / m ^2, and this was heated and dried in a temperature atmosphere of 170 ° C. to obtain a foam sheet. When this foam sheet was applied as a table cloth, the table cloth had excellent cushioning properties and anti-slip properties, and the back surface of the cloth had a beautiful suede-like matte surface, which was highly aesthetic.

Example 3 50 parts by weight of a urethane resin (Superflex E2000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and an acrylic resin (Dainippon Ink and Chemicals, Inc.) were used on both sides of a non-woven fabric made of polyester / pulp fiber and having a basis weight of 35 g / m ^2. 50 parts by weight of Boncoat 350), 5 parts by weight of foaming agent (Boncoat F-1 made by Dainippon Ink and Chemicals, Inc.), heat-sensitive expandable microbeads (Matsumoto Microsphere F-30 made by Matsumoto Yushi-Seiyaku Co., Ltd.). 10 parts by weight and 5 parts by weight of titanium oxide powder (Taipaque W-10 manufactured by Ishihara Sangyo Co., Ltd.) were mechanically foamed into an emulsion of a urethane resin so that a coating amount of 100 g / m ² was obtained with a knife coater. It was applied, dried by heating in a 170 ° C. atmosphere, and then crushed with a calendar roll to obtain a foam sheet. When this foam sheet was applied as a wiping cloth, it had a fine and deep concave-convex surface, resulting in a cloth having high wiping property and soft touch.

Example 4 100 parts by weight of a urethane resin (Superflex E2000 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and a foaming agent (Dainippon Ink and Chemicals, Inc.) on the coated surface of a base cloth for a light-shielding curtain coated with a resin. Bon Coat F-1)
5 parts by weight of thermosensitive foaming microbeads (Matsumoto Yushi-Seiyaku Co., Ltd. Matsumoto Microspheres-F-30) 3 parts by weight of a urethane resin emulsion were mechanically foamed and coated with a knife coater at a coating amount of 150 g / m 2. ^It was applied so that it would be ^2, and this was heated and dried in a temperature atmosphere of 170 ° C. to obtain a foam sheet. When this foam sheet is applied as a light-shielding curtain, the light-shielding curtain has a softer and warmer touch than a conventional product having a rubber product-like appearance.

Example 5 100 parts by weight of a urethane resin (Superflex 4500 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and a foaming agent (manufactured by Dainippon Ink and Chemicals, Inc.) on one side of a non-woven fabric made of polyester fiber and having a basis weight of 60 g / m ² . Boncoat F-1) 5 parts by weight,
Thermosensitive foaming microbeads (Matsumoto Yushi-Seiyaku Co., Ltd. Matsumoto Microspheres-F-30) 3 parts by weight of urethane resin emulsion were mechanically foamed so that the coating amount was 150 g / m ² with a knife coater. Was applied to a non-woven fabric release sheet to form a foamed resin layer on one surface of the release sheet. Then
A sponge material made of urethane foam was adhered to the foamed resin layer, and then the release sheet was peeled off to form a broken surface of the foamed resin layer on the surface layer of the sponge material to obtain a foam sheet. When this foam sheet was applied as a cosmetic sponge, it became a cosmetic sponge having excellent touch-up properties for cosmetics and soft touch due to its fine and deep uneven surface.

Example 6 100 parts by weight of a urethane resin (Superflex 4500 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and a foaming agent (manufactured by Dainippon Ink and Chemicals, Inc.) on one side of a non-woven fabric made of polyester fiber and having a basis weight of 60 g / m ² . Boncoat F-1) 5 parts by weight,
Thermosensitive foaming microbeads (Matsumoto Yushi-Seiyaku Co., Ltd. Matsumoto Microspheres-F-30) 3 parts by weight of a urethane resin emulsion was mechanically foamed to a coating amount of 150 g / m ² with a knife coater. Was applied to a non-woven fabric release sheet to form a foamed resin layer on one surface of the release sheet. Then
As shown in FIG. 4, an adhesive 34 is applied on the resin film 32 in a pattern such as letters and patterns, and the foamed resin layer 33 is adhered onto the adhesive 34. Thereafter, as shown in FIGS. 5 and 6, the release sheet 35 is peeled off, so that only the portions on the resin film 32 to which the adhesive 34 is applied, such as letters and patterns, are formed together with the bubbles 36 formed by mechanical foaming. A foam sheet 31 was obtained in which the foamed resin layer 33 with the thermally expanded balloons 37 of heat-sensitive foamed microbeads scattered was left.
The fracture surface of the surface of the foamed resin layer forming patterns such as letters and patterns has a fine and deep uneven surface, and it was possible to apply a coating with a beautiful suede-like matte surface on the resin film.

[0045]

According to the present invention, the above-mentioned structure is provided.
In the foam sheet described, the surface of the foamed resin layer formed on the surface of the base material is rich in variations in which balloons that have been thermally expanded are incorporated into a three-dimensional network structure formed by mechanical foaming and scattered. The balloon in the surface layer portion of the foamed resin layer has a structure, a part of which protrudes to the surface of the foamed resin layer, and the uneven surface is a conventional one in which the balloons are scattered in the resin that has not been mechanically foamed. Compared with this, since the unevenness is fine and the undulations are small, a fine and deep soft uneven surface is created. Further, in this foam sheet, since the foamed resin layer has a structure in which the thermally expanded balloons are taken in and scattered in the three-dimensional mesh structure formed by mechanical foaming, the foamed resin layer is soft and repulsive. Rich

This foam sheet has a fine and deep soft uneven surface, and is flexible and rich in impact resilience.
It can be applied to a wide range of fields such as table cloths, wiping cloths, interior and exterior materials, suede paint, clothing, shoes and bags.

In the foam sheet according to claim 2,
As a raw material for the foamed resin layer as the skin of the foam sheet,
Since polyurethane resin and acrylic resin are used,
The discoloration resistance and deterioration resistance are further improved, and a skin having a softer texture can be formed.

In the foam sheet according to claim 3,
Balloons of heat-sensitive expanded microbeads that have been heat-expanded are scattered on the fracture surface of the foamed resin layer, and the unevenness of the uneven surface is larger than that of the foamed resin layer that is only mechanically foamed.For example, when this is applied to a cosmetic sponge, It is possible to obtain a cosmetic sponge having an epidermis with extremely good suitability for powder cosmetics. In addition, by changing the type of release sheet according to the application, the size and shape of the uneven surface of the foam sheet,
The structure can be set freely.

In the method for producing a foam sheet according to claim 4, the method has a fine, deep and soft uneven surface,
In addition, it is possible to obtain a foam sheet that is flexible and has a high impact resilience.

In the method for producing a foam sheet according to claim 5, the resin is mechanically foamed at a foaming ratio of 1.5 to 6.0, so that the foamed resin layer in the foam sheet is damaged during use. It is possible to manufacture a foam sheet having sufficient strength to prevent cracking and cracking, and a porosity necessary for deriving predetermined surface irregularity and softness.

In the method for producing a foam sheet according to the sixth aspect, since the heat-sensitive expandable microbeads are contained in a ratio of 1 to 40 parts by weight with respect to 100 parts by weight of the resin, the uneven surface of the foamed resin layer is formed. It is possible to manufacture a foam sheet which has large undulations, is flexible, is rich in impact resilience, and is excellent in strength, and in which the foamed resin layer does not easily peel off from the substrate during use.

In the method for producing a foam sheet according to claim 7, the thermosensitive foam microbeads have a diameter of 1 when not expanded.
By thermally expanding to a size of 0 to 20 μm to 30 to 80 μm, it is possible to obtain a foam sheet having a fine, deep and soft uneven surface and being flexible and rich in impact resilience. In particular, by changing the coefficient of thermal expansion of the heat-sensitive expandable microbeads within the above range, the depth, flexibility and impact resilience of the uneven surface of the foam sheet can be adjusted appropriately according to the application.

In the method for producing a foam sheet according to the eighth aspect, balloons of heat-expanded heat-expandable micro-beads are scattered on the broken surface of the foamed resin layer, and the uneven surface is formed only by mechanical foaming. The size, shape, and structure of the undulations on the uneven surface of the foam sheet can be set freely by changing the type of the release sheet that is larger than the foam resin layer and according to the application.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing an uneven surface of a foam sheet of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a state in which a base material is bonded to a foamed resin layer.

FIG. 3 is an electron micrograph showing a structure of a fracture surface of a foamed resin layer obtained by peeling a release sheet from the foamed resin layer.

FIG. 4 is an enlarged cross-sectional view showing a state in which an adhesive is applied in a pattern such as letters and patterns on a resin film.

5 is an enlarged cross-sectional view showing a state in which a foamed resin layer is bonded onto the adhesive shown in FIG.

FIG. 6 shows a foam sheet in which the release sheet is peeled from the foamed resin layer shown in FIG. 5, and the foamed resin layer remains only on the resin film where the adhesive is applied, such as letters and patterns. Enlarged sectional view.

[Explanation of symbols]

12, 22, 32 ... Base material 13, 23, 33 ... Foamed resin layer 14, 24, 36 ... Mechanical foaming foam 15, 25, 37 ... Thermally expanded balloon of thermosensitive foamed microbeads

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area B29K 105: 04 B29L 9:00

Claims (8)

[Claims] 1. A foam sheet having a foamed resin layer formed on a surface of a substrate, wherein thermally expanded balloons of heat-sensitive foamed micro beads are scattered in the foamed resin layer together with bubbles due to mechanical foaming. A characteristic foam sheet. 2. The foam sheet according to claim 1, wherein the resin comprises polyurethane and an acrylic resin. 3. A foamed body in which a foamed resin layer in which heat-expanded microbeads of thermally expanded balloons are scattered along with bubbles formed by mechanical foaming is formed on one surface of a release sheet, and the foamed resin layer is adhered to a substrate. A foam sheet, wherein a fracture surface of a foamed resin layer formed by peeling the release sheet from the sheet is used as a skin of the foam sheet. 4. A method for producing a foam sheet having a foamed resin layer formed on a surface of a base material, which comprises mechanically foaming a resin containing heat-sensitive expandable microbeads, and applying the foamed resin to the surface of the base material. Then, the foamed resin layer is formed by heating and expanding the heat-sensitive foamed microbeads in the foamed resin layer by heating. 5. The method for producing a foam sheet according to claim 4, wherein the resin is mechanically foamed 1.5 to 6.0 times. 6. The method for producing a foam sheet according to claim 4, wherein 1 to 40 parts by weight of the heat-sensitive expandable microbeads are included with respect to 100 parts by weight of the resin. 7. The method for producing a foam sheet according to claim 4, wherein the heat-sensitive expandable microbeads are thermally expanded to have a diameter of 10 to 20 μm when unexpanded to 30 to 80 μm. 8. A foamed resin layer is formed by mechanically foaming a resin containing heat-sensitive expandable microbeads, applying the heat-sensitive expandable microbeads on one surface of a release sheet, and heating the foamed resin to expand the heat-sensitive expandable microbeads. Then, the foamed resin layer is adhered to a base material, and then the release sheet is peeled off to form a fracture surface of the foamed resin layer on the surface layer of the base material.