JP2022104367A - Self-adsorptive laminate - Google Patents

Abstract

To provide a self-adsorptive laminate that achieves unevenness followability during pasting, long-term adhesion stability, and reworkability after long-term use at high level.SOLUTION: Provided is a self-adsorptive laminate, which is a self-adsorptive laminate formed by laminating a substrate and a self-adsorptive foam sheet made of an acrylic resin foam, and in which the density of the self-adsorptive foam sheet is 0.3 g/cm3 or more and 0.7 g/cm3 or less, and the 25% compressive strength of the self-adsorptive foam sheet is 3 kPa or more and 15 kPa or less.SELECTED DRAWING: None

Description

The present invention relates to a self-adsorptive laminate.

Conventionally, as a sticking sheet used by sticking to an adherend such as a wall or a window glass, it is made of a foam material having a large number of fine pores and has a self-adsorptive sheet-like member, that is, a self-adsorbable foam sheet. (Hereinafter, it may be simply referred to as "foam sheet".) Is used. The adhesive mode of the self-adsorptive foam sheet is not adhesive adhesion but adsorption to an adherend using fine pores. Therefore, the self-adsorptive foam sheet is easier to reattach than the conventional adhesive sheet that employs adhesive adhesion, and is suitably used for applications such as wallpaper, posters, and stickers. When used in these applications, the self-adsorptive foam sheet is usually used in the form of a self-adsorptive laminate (hereinafter, may be simply referred to as "laminated sheet") laminated with a base material. By decorating the surface of the self-adsorptive laminate on the substrate side with printing or the like, it can be advantageously used for the above-mentioned applications.

Then, for example, in Patent Document 1, as a self-adsorptive laminate that can be peeled off from gypsum board or the like, an adhesive made of open cell foam having a density of 0.2 g / cm ³ or more and 1.5 g / cm ³ or less is adhered. A graphic sheet in which a layer is arranged on a base film layer is disclosed.

Japanese Unexamined Patent Publication No. 2017-218561

However, when the conventional self-adsorptive laminate is used by being attached to an adherend surface having irregularities such as a wall surface on which wallpaper is attached, it exhibits excellent unevenness followability and lasts for a long period of time. There was room for improvement in that the occurrence of floating and peeling during use could be suppressed, and the prevention of resin residue on the adherend surface during peeling after long-term use could be performed side by side.

Therefore, it is an object of the present invention to provide a self-adsorptive laminate in which unevenness followability at the time of sticking, adhesion stability for a long period of time, and reworkability after long-term use are arranged side by side at a high level. ..

The present inventor has made diligent studies for the purpose of solving the above problems. Then, by using a self-adhesive foam sheet made of an acrylic resin foam whose density and compressive strength are both within a predetermined range, the present inventor can follow the unevenness at the time of sticking and stabilize the adhesion for a long period of time. We have found that the properties and the reworkability after long-term use can be arranged at a high level, and completed the present invention.

That is, the present invention aims to advantageously solve the above problems, and the self-adsorptive laminate of the present invention comprises laminating a base material and a self-adsorbent foam sheet made of an acrylic resin foam. The self-adsorptive foam sheet is characterized by having a density of 0.3 g / cm ³ or more and 0.7 g / cm ³ or less and a 25% compression strength of 3 kPa or more and 15 kPa or less. As described above, if both the density and the compressive strength of the self-adsorbing foamed sheet are within a predetermined range, the unevenness-following property at the time of sticking, the long-term adhesion stability, and the reworkability after long-term use can be obtained. It can be placed side by side at a high level.
In the present invention, the "density" and "25% compressive strength" of the self-adsorbing foam sheet can be measured by using the methods described in Examples, respectively.

Here, in the self-adsorptive laminate of the present invention, it is preferable that the average thickness of the self-adsorptive foamed sheet is 0.05 mm or more and 1 mm or less. When the average thickness of the self-adsorptive foamed sheet is 0.05 mm or more and 1 mm or less, the unevenness-following property can be further improved, and the increase in the own weight and the decrease in the workability can be suppressed.
In the present invention, the "average thickness" of the self-adsorptive foamed sheet refers to the arithmetic mean value of the thickness of any six points of the self-adsorbable foamed sheet.

Further, the self-adsorptive laminate of the present invention is preferably formed of an acrylic resin in which the acrylic resin foam is crosslinked. If the acrylic resin foam is made of crosslinked acrylic resin, it is possible to further suppress the generation of resin residue on the adherend surface at the time of peeling, and further enhance the reworkability.

Further, in the self-adsorptive laminate of the present invention, it is preferable that the acrylic resin foam contains a defoaming agent. This is because the acrylic resin foam containing the defoaming agent has a good open cell structure and can satisfactorily release air at the time of sticking.

Further, in the self-adsorptive laminate of the present invention, the unevenness follow-up rate of the self-adsorptive foamed sheet is preferably 30% or more and 90% or less. When the unevenness follow-up rate is at least the above lower limit value, the adhesion stability over a long period of time can be further improved. Further, when the unevenness follow-up rate is not more than the above upper limit value, it is possible to further suppress the generation of resin residue on the adherend surface at the time of peeling.
In the present invention, the "concavo-convex follow-up rate" of the self-adsorptive foam sheet can be measured by using the method described in Examples.

Further, in the self-adsorptive laminate of the present invention, the initial self-adhesive force of the self-adsorptive foamed sheet is preferably 0.01 N / cm or more and 0.50 N / cm or less. When the initial self-adhesive force is at least the above lower limit value, the self-adsorptive laminated body can be satisfactorily attached to the adherend. Further, when the initial self-adhesive force is not more than the above upper limit value, the reworkability can be enhanced and the damage to the adherend at the time of peeling can be suppressed.
In the present invention, the "initial self-adhesive force" of the self-adsorptive foam sheet can be measured by using the method described in Examples (self-adhesive force (initial)).

Further, the self-adsorptive laminate of the present invention preferably has a self-adhesive force of 0.10 N / cm or more and 1.0 N / cm or less after the accelerated test of the self-adsorbent foam sheet. If the self-adhesive force after the accelerated test is equal to or higher than the above lower limit value, sufficient long-term adhesion stability can be ensured. Further, if the self-adhesive force after the accelerated test is not more than the above upper limit value, the reworkability can be enhanced and the damage to the adherend at the time of peeling can be suppressed.
In the present invention, the "self-adhesive force after the accelerated test" of the self-adsorptive foam sheet can be measured by using the method described in Examples (self-adhesive force (after the accelerated test)).

The self-adsorptive laminate of the present invention has a high level of unevenness-following property at the time of sticking, adhesion stability for a long period of time, and reworkability after long-term use. Therefore, for example, wallpaper. It can be suitably used for sticking to an adherend surface having irregularities such as.

According to the self-adsorptive laminate of the present invention, it is possible to make the unevenness-following property at the time of sticking, the adhesion stability for a long period of time, and the reworkability after long-term use parallel to each other at a high level.

Hereinafter, embodiments of the present invention will be described in detail.
Here, the self-adsorptive laminate of the present invention is not particularly limited, and is used by being attached to an adhered surface having irregularities such as a wall surface on which wallpaper is attached, and after use, the adhered surface is used. It can be easily peeled off from.

(Self-adsorptive laminate)
The self-adsorptive laminate of the present invention is formed by laminating a base material and a self-adsorptive foam sheet made of an acrylic resin foam. The self-adsorptive laminate of the present invention is a self-adsorptive foamed sheet having a density of 0.3 g / cm ³ or more and 0.7 g / cm ³ or less and a 25% compressive strength of 3 kPa or more and 15 kPa or less. Characterized by use.
In the structure of the self-adsorptive laminate of the present invention, the self-adsorptive foam sheet is laminated on one side in the thickness direction of the base material, and one surface (the surface bonded to the adherend at the time of use) is self. It is not particularly limited as long as it is composed of an adsorptive foam sheet. For example, the self-adsorptive laminate may have a structure in which an arbitrary layer such as an adhesive layer is interposed between the base material and the self-adsorptive foamed sheet.

Here, in general, it is necessary to use a soft self-adsorptive foam sheet in order to improve the unevenness followability at the time of pasting, but when a soft self-adsorptive foam sheet is used, the self-adsorptive laminated body is peeled off. Sometimes the resin tends to remain on the adherend surface. Further, in order to improve the adhesion stability over a long period of time, it is necessary to use a self-adsorptive foam sheet having a large adhesive force, but when a self-adsorptive foam sheet having a large adhesive force is used, the self-adsorptive lamination In addition to the fact that the resin tends to remain on the adherend surface when the body is peeled off, the adherend may be damaged. Therefore, usually, there is a trade-off relationship between the unevenness-following property at the time of pasting and the adhesion stability over a long period of time and the reworkability after long-term use, and it is difficult to make them stand side by side. However, in the self-adsorptive laminate of the present invention, since the acrylic resin foam having both the density and the 25% compressive strength in a specific range is used as the self-adsorptive foam sheet, the unevenness-following property at the time of sticking is used. And, the long-term adhesion stability and the reworkability after long-term use can be made to stand side by side at a high level.

<Base material>
The base material is not particularly limited, and a paper base material other than synthetic paper, a synthetic paper base material, a plastic base material, a fiber base material, a metal base material, a glass base material, and the like can be used. The thickness of the base material is not particularly limited, but can be, for example, 10 μm or more and 200 μm or less.

Examples of the paper base material include high-quality paper, art paper, coated paper, kraft paper, and those obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials.

The synthetic paper base material is not particularly limited, and examples thereof include those in which the surface layer is made into paper by a combination of a thermoplastic resin and an inorganic filler.

Examples of the plastic base material include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polystyrene resins; polyvinyl chloride resins; acrylic resins; polycarbonate resins; polyamide resins; fluororesins such as polytetrafluoroethylene. Resins; and sheet-like substrates consisting of mixtures or laminates of these resins.

Examples of the fiber base material include natural fibers such as cotton and silk; polyamide-based synthetic fibers; polyester-based synthetic fibers; polypropylene-based synthetic fibers; polyvinyl chloride-based synthetic fibers; polyvinyl alcohol-based synthetic fibers; semi-synthetic fibers such as acetate. Examples include recycled artificial fibers such as rayon; and sheet-like substrates made of mixtures or laminates of these fibers.

The metal base material is not particularly limited, and examples thereof include metals such as iron, copper, aluminum, gold, platinum, and silver, and sheet-like base materials made of alloys or laminates thereof.

The glass base material is not particularly limited, and examples thereof include a sheet-like base material made of soda lime glass, borosilicate glass, non-alkali glass, quartz glass, and the like.

<Self-adsorbing foam sheet>
The self-adsorptive foam sheet is composed of an acrylic resin foam having a density of 0.3 g / cm ³ or more and 0.7 g / cm ³ or less and a 25% compressive strength of 3 kPa or more and 15 kPa or less.

[Acrylic resin foam]
The acrylic resin foam can be formed by foaming and molding a composition for a foam sheet containing an acrylic resin and, if necessary, curing it. The acrylic resin foam is preferably formed of a crosslinked acrylic resin from the viewpoint of suppressing the generation of resin residue on the adherend surface at the time of peeling and improving the reworkability.

Here, the composition for a foam sheet used for forming the acrylic resin foam contains an acrylic resin, and is optionally selected from the group consisting of a cross-linking agent, a defoaming agent, a solvent, and other additives. A composition further containing the above can be used.

As the acrylic resin, a polymer containing a (meth) acrylate monomer unit and optionally further containing another monomer unit can be used.
In addition, in this invention, "the polymer contains a monomer unit" means "the polymer obtained by using the monomer contains a repeating unit derived from a monomer". do. Further, in the present invention, "(meth) acrylate" means acrylate and / or methacrylate.

Here, the (meth) acrylate monomer unit is a repeating unit derived from the (meth) acrylate monomer. The (meth) acrylate monomer is not particularly limited, and for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, (. Meta) sec-butyl acrylate, (meth) n-heptyl acrylate, (meth) n-hexyl acrylate, (meth) n-octyl acrylate, 2-ethyl hexyl (meth) acrylate, n (meth) acrylate -(Meta) acrylic acid alkyl ester monomers such as dodecyl; (meth) acrylic acid 2-methoxyethyl, (meth) acrylic acid 3-methoxypropyl, (meth) acrylic acid 3-methoxybutyl, (meth) acrylic acid Examples include (meth) acrylic acid alkoxyalkyl ester monomers such as ethoxymethyl; and the like. Among them, n-butyl acrylate and / or 2-ethylhexyl acrylate are used as the (meth) acrylate monomer from the viewpoint of improving the unevenness-following property at the time of sticking and the long-term adhesion stability. Is preferable.
The (meth) acrylate monomer may be used alone or in combination of two or more. Further, in the present invention, "(meth) acrylic" means acrylic and / or methacrylic.

The ratio of the (meth) acrylate monomer unit in the polymer shall be 60% by mass or more and 95% by mass or less, assuming that all the repeating units (all monomer units) contained in the polymer are 100% by mass. Is preferable.

The other monomer unit is not particularly limited, and examples thereof include the monomer unit described in International Publication No. 2018/151274. Specifically, the other monomer unit is not particularly limited, and is a repeating unit derived from an unsaturated carboxylic acid monomer, a repeating unit derived from a vinyl cyanide monomer, and an alkenyl aromatic simple unit. Repeat units derived from the monomer can be mentioned.
The acrylic resin preferably contains, as the other monomer unit, a monomer unit having a functional group capable of forming a crosslinked structure by using a crosslinking agent described in detail later.

From the viewpoint of obtaining an acrylic resin foam having excellent unevenness followability during pasting and long-term adhesion stability, it is preferable to use an acrylic resin having a low glass transition temperature, and the acrylic resin has a glass transition. The temperature is more preferably −25 ° C. or lower.
In the present invention, the "glass transition temperature" is based on JIS K7121 by using a differential scanning calorimeter under the conditions of a measurement temperature of -50 ° C or higher and 160 ° C or lower and a heating rate of 10 ° C / min. Can be measured.

The cross-linking agent that can be blended in the foam sheet composition is not particularly limited as long as it can cross-link the acrylic resin, and is not particularly limited. Examples thereof include polyfunctional isocyanate-based cross-linking agents such as propanetolylene diisocyanate and diphenylmethane triisocyanate; metal salt-based cross-linking agents; metal chelate-based cross-linking agents; peroxide-based cross-linking agents; and the like.
Among them, as the cross-linking agent, an epoxy-based cross-linking agent or an oxazoline-based cross-linking agent is preferable.

The blending amount of the cross-linking agent is not particularly limited, and may be 0.1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the acrylic resin. When the blending amount of the cross-linking agent is at least the above lower limit value, the strength of the acrylic resin foam can be ensured, and the generation of resin residue on the adherend surface at the time of peeling can be suppressed. Further, when the blending amount of the cross-linking agent is not more than the above upper limit value, the flexibility of the acrylic resin foam can be ensured, and the unevenness-following property at the time of sticking and the long-term adhesion stability can be improved.

As the defoaming agent that can be blended in the composition for foam sheet, a known defoaming agent such as a higher fatty acid salt or a surfactant can be used. The foam stabilizer may remain in the acrylic resin foam formed by using the foam sheet composition.

The blending amount of the defoaming agent is not particularly limited, and may be 0.1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the acrylic resin. When the blending amount of the foam stabilizer is not less than the above lower limit, an acrylic resin foam having a good open cell structure can be obtained.

The solvent that can be arbitrarily contained in the composition for a foamed sheet of the present invention is not particularly limited, and examples thereof include water and an organic solvent. Of these, water is preferable.

Other additives that can be incorporated into the foam sheet composition include, for example, foaming aids, thickeners, fillers, preservatives, fungicides, gelling agents, flame retardants, antioxidants, and oxidations. Examples thereof include inhibitor, pigment, dye, tackifier, conductive compound, water resistant agent, oil resistant agent and the like. The above-mentioned other additives are not particularly limited, and known additives such as those described in International Publication No. 2016/147679 can be used.

The formation of the acrylic resin foam using the above-mentioned composition for foam sheet is not particularly limited, and for example, the prepared composition for foam sheet is foamed to obtain an uncured (uncrosslinked) foam. After that, the foam can be formed into a sheet and cured (crosslinking reaction) if necessary.

Here, the composition for a foamed sheet can be prepared by mixing the above-mentioned components by any method and order. For example, when acrylic resin latex is used to prepare a composition for a foam sheet, a cross-linking agent, a defoaming agent, other additives, etc. may be added to the latex as necessary and mixed by a known method. Just do it. When a solid acrylic resin is used instead of a solvent for preparing the composition for the foam sheet, the solid acrylic resin and a cross-linking agent, a defoaming agent, and the like added as needed are used. Additives and the like may be mixed by a known method (for example, using a known roll, Henschel mixer, kneader, etc.).

The viscosity of the foamed sheet composition containing the solvent (for example, in the form of an emulsion or dispersion) is preferably 1,000 mPa · s or more, and more preferably 2,000 mPa · s or more. It is more preferably 3,500 mPa · s or more, more preferably 10,000 mPa · s or less, and even more preferably 5,500 mPa · s or less. If the viscosity of the foamed sheet composition is 1,000 mPa · s or more, liquid dripping occurs when the foam formed from the foamed sheet composition is coated on a substrate or the like, making it difficult to control the thickness. Can be prevented from becoming. On the other hand, if the viscosity of the foamed sheet composition is 10,000 mPa · s or less, it does not become difficult to control the foaming ratio by mechanical foaming when forming the foamed sheet.
The viscosity of the foamed sheet composition can be measured at a temperature of 23 ° C. using a B-type viscometer.

Further, as a method for foaming the composition for a foam sheet, it is preferable to adopt mechanical foaming from the viewpoint of obtaining an acrylic resin foam having excellent flexibility. The foaming ratio may be adjusted as appropriate, but is preferably 1.5 times or more, more preferably 1.6 times or more, and preferably 2.2 times or less, more preferably 2.0 times or less. be. When the foaming ratio is at least the above lower limit value, it is possible to obtain an acrylic resin foam having excellent unevenness followability at the time of sticking and adhesion stability over a long period of time. Further, when the foaming ratio is not more than the above upper limit value, it is possible to suppress the generation of resin residue on the adherend surface at the time of peeling.

The mechanical foaming is not particularly limited, but can be performed by mixing a certain amount of air into the emulsion or dispersion of the foamed sheet composition and stirring continuously or in a batch manner with an oak mixer, a whipper or the like. .. The foam (foamed emulsion or foamed dispersion) thus obtained becomes creamy.

Further, the method for forming the foam into a sheet is not particularly limited. As a suitable method, for example, a method of coating a foam on a desired base material and forming it into a sheet can be mentioned. By coating the desired base material with the foam in this way and proceeding with the crosslinking reaction, a laminated sheet in which the foamed sheet is directly provided on the base material can be obtained.

The foam can be coated on a releasable sheet (process paper having releasability, etc.) instead of the above-mentioned base material. If the foam is coated on the releasable sheet and the cross-linking reaction is allowed to proceed, a laminate in which the foam sheet is directly provided on the releasable sheet can be obtained. Then, by peeling the releasable sheet from the foamed sheet of this laminated body, the foamed sheet can be obtained alone (as an independent film).

As a method of coating the foam on a base material or a releasable sheet (hereinafter, these may be collectively referred to as "base material, etc."), an applicator, a bar coater, a roll coater, a reverse roll coater, and a screen are used. Commonly known coating devices such as coaters, doctor knife coaters, and comma knife coaters can be used.

As a method for cross-linking the foam formed into a sheet shape, a method of heating and drying the foam is preferable. The method of heat drying is not particularly limited as long as it is a method capable of drying and cross-linking the foam formed into a sheet, and is a known drying furnace (for example, a hot air circulation type oven, a hot oil circulation hot air chamber). , Far infrared heater chamber) can be used. The drying temperature can be, for example, 60 ° C. or higher and 180 ° C. or lower. Further, it is preferable to perform multi-step drying such that drying is performed from the inside at a low temperature in the early stage of drying and sufficiently dried at a higher temperature in the latter stage of drying, instead of performing drying at a constant temperature.

The laminate of the acrylic resin foam and the base material or the like obtained as described above is not particularly limited, but for example, after a separator film is attached to a surface having self-adsorption property, a winder is used. It can be wound up, cut by press cutting, slitter, etc. and processed into a size that is easy to use.

[density]
The density of the self-adhesive foam sheet made of the acrylic resin foam needs to be 0.3 g / cm ³ or more and 0.7 g / cm ³ or less, and 0.4 g / cm ³ or more and 0.55 g / cm ³ The following is preferable. When the density is not more than the above upper limit value, the self-adsorptive foamed sheet can be provided with appropriate flexibility, and the unevenness-following property at the time of sticking and the long-term adhesion stability can be improved. Further, when the density is equal to or higher than the above lower limit value, the self-adsorptive foamed sheet can be provided with an appropriate strength, and the generation of resin residue on the adherend surface at the time of peeling can be suppressed.

[25% compressive strength]
Further, the 25% compressive strength of the self-adsorptive foam sheet made of an acrylic resin foam needs to be 3 kPa or more and 15 kPa or less, preferably 4 kPa or more, and more preferably 4.5 kPa or more. It is preferably 10 kPa or less, and more preferably 8 kPa or less. When the 25% compressive strength is not more than the above upper limit value, the self-adsorptive foamed sheet can be provided with appropriate flexibility, and the unevenness-following property at the time of sticking and the long-term adhesion stability can be improved. Further, when the 25% compressive strength is at least the above lower limit value, the self-adsorbing foamed sheet can be provided with an appropriate strength, and the generation of resin residue on the adherend surface at the time of peeling can be suppressed.

[Concavo-convex follow-up rate]
Further, the unevenness follow-up rate of the self-adsorptive foam sheet made of an acrylic resin foam is preferably 30% or more, more preferably 40% or more, preferably 90% or less, and preferably 85% or less. Is more preferable. When the unevenness follow-up rate is at least the above lower limit value, the adhesion stability for a long period of time can be improved. Further, when the unevenness follow-up rate is not more than the above upper limit value, it is possible to suppress the generation of resin residue on the adherend surface at the time of peeling.
Here, if the adhesive strength of the self-adhesive foam sheet is increased so that it adheres well to the adherend surface having irregularities, it is easy to damage a brittle adherend such as wallpaper at the time of peeling, but the adhesive strength is low. It does not stick to the adherend surface that has irregularities. Therefore, it is effective from the viewpoint of adhesion stability and adherend protection that it is possible to adhere well without increasing the adhesive force by increasing the unevenness follow-up rate and securing the contact area with the adherend. Is.

[Initial self-sufficiency]
Further, the initial self-adhesive force of the self-adsorptive foam sheet made of an acrylic resin foam is preferably 0.01 N / cm or more, more preferably 0.05 N / cm or more, and 0.50 N / cm or less. It is preferably 0.30 N / cm or less, and more preferably 0.30 N / cm or less. When the initial self-adhesive force is at least the above lower limit value, the self-adsorptive laminated body can be satisfactorily attached to the adherend. Further, if the initial self-adhesive force is not more than the above upper limit value, damage to the adherend at the time of peeling can be suppressed even when the adherend is attached to a brittle adherend such as wallpaper.

[Self-adhesiveness after accelerated test]
Further, the self-adhesive force of the self-adsorptive foam sheet made of an acrylic resin foam is preferably 0.10 N / cm or more, more preferably 0.20 N / cm or more, and more preferably 1.0 N / cm after the accelerated test. It is preferably cm or less, and more preferably 0.70 N / cm or less. If the self-adhesive force after the accelerated test is equal to or higher than the above lower limit value, sufficient long-term adhesion stability can be ensured. In addition, if the self-adhesive force after the accelerated test is equal to or less than the above upper limit value, the reworkability is enhanced and damage to the adherend at the time of peeling is suppressed even when the adherend is attached to a brittle adherend such as wallpaper. Can be done.

[Average thickness]
The self-adsorptive foam sheet made of an acrylic resin foam has an average thickness of 0.05 mm or more, more preferably 100 μm or more, preferably 1 mm or less, and 500 μm or less. Is more preferable. When the average thickness is at least the above lower limit value, it is possible to improve the unevenness followability at the time of pasting and to suppress the unevenness shape of the adherend surface from being transferred to the substrate side. Further, when the average thickness is not more than the above upper limit value, the increase of the own weight can be suppressed and the workability can be improved.

The properties of the acrylic resin foam described above (density, 25% compressive strength, unevenness follow-up rate, average thickness, self-adhesive force, etc.) are, for example, the composition and solid content concentration of the foam sheet composition, and the bubbles during foaming. It can be adjusted by changing the mixing ratio, the thickness of coating the foam, and the conditions of drying and crosslinking.

<Manufacturing method of self-adsorptive laminate>
When the self-adsorptive foam sheet made of the acrylic resin foam described above is molded on the substrate, the obtained laminate is used as it is, or if necessary, it is cut or otherwise processed and then self-adsorbed. It can be used as a sex laminate.
Further, when the self-adsorptive foam sheet made of the acrylic resin foam described above is molded on the releasable sheet, the self-adsorptive foam sheet peeled off from the releasable sheet is laminated and integrated with the base material. By doing so, a self-adsorptive laminate can be obtained. Here, the self-adsorptive foam sheet and the base material can be integrated by using a known method such as the use of an adhesive, fusion, and pressure bonding.

<Use of self-adsorptive laminate>
The self-adhesive laminate can be printed on its substrate surface by, for example, offset printing, seal printing, flexographic printing, silk screen printing, gravure printing, laser printer, thermal transfer printer, inkjet printer or the like. Further, the self-adsorptive laminate may be decorated with a base material.
The self-adsorbing laminate is not particularly limited, and can be advantageously used as a sheet to be attached to an adherend surface having irregularities, such as a wallpaper to be attached on a wallpaper.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. In the following description, "%" and "part" representing quantities are based on mass unless otherwise specified.
Then, in Examples and Comparative Examples, the density of the self-adsorptive foam sheet, the 25% compressive strength and the unevenness follow-up rate, and the self-adhesive strength of the self-adsorptive laminate (initially and after the accelerated test), adhesion stability and reworkability. Was evaluated by the following method.

<Density>
The prepared self-adsorptive laminate was cut into a size of 20 cm × 20 cm to prepare a test piece. The mass of the excised test piece: Xg was precisely weighed. Further, the mass of the base material cut out to 20 cm × 20 cm: Yg was precisely weighed. After that, the thicknesses of the prepared self-adsorptive laminate and the base material are measured with a thickness gauge, and the thickness of the base material is subtracted from the thickness of the self-adsorbable laminate to obtain the thickness of the self-adsorbent foam sheet: Tcm. Obtained. At this time, the thickness value was calculated from the average value when 6 points were measured. By substituting the measured values of X, Y, and T into the following equation, the density of the self-adsorbing foam sheet was calculated.
Density (g / cm ³ ) = (XY) / (T × 20 × 20)
<25% compressive strength>
A self-adsorptive foam sheet was cut out from the self-adsorptive laminate to a size of 25 mm × 25 mm × 20 mm and used as a test piece.
Then, in accordance with JIS K6254, the stress value (kPa) when compressed by 25% of the initial thickness at a speed of 10 mm / min using an autograph (manufactured by Shimadzu Corporation, "AG-IS") was measured and 25. % Compressive strength.
<Concavo-convex follow-up rate>
The prepared self-adsorptive laminate was cut into a size of 125 mm × 25 mm and used as a test piece. Then, the test piece was attached to a wallpaper cut out to a size of 125 mm × 50 mm (“LB-9424” manufactured by Lilycolor), and a load of 2 kgf was applied from the top of the test piece to crimp the wallpaper and the test piece with a roller.
Next, the test piece attached to the wallpaper is cut out from above with a shaving blade so that the cross section (adhesive surface) is exposed, and the cross section is observed with a digital microscope (Kieence, "VHK-6000") to observe the cross section of the wallpaper surface. And the contact rate of the test piece with the self-adhesive foam sheet (= (length of the cross section of the self-adhesive foam sheet in close contact with the wallpaper / length of the cross section of the wallpaper surface) x 100%) It was set to (%).
<Self-adhesiveness (initial)>
The prepared self-adsorptive laminate was cut into a size of 125 mm × 25 mm and used as a test piece. Next, a wallpaper cut out to a size of 125 mm × 50 mm (“LB-9424” manufactured by Lilycolor) was attached to an aluminum plate of the same size with double-sided tape to prepare an adherend. The surface of the test piece on the self-adsorptive foam sheet side is attached to the surface of the adherend on the wallpaper side, and a load of 2 kgf is applied from the top of the test piece to crimp it with a roller. It was left for 1 hour. After that, the end of the test piece was fixed to the upper chuck of the autograph (manufactured by Shimadzu Corporation, "AG-IS"), and the adherend was fixed to the lower chuck at 23 ° C. and 50% RH environment. A 180 degree peel test was performed at a rate of 300 mm / min. The peeling force (N / cm) at this time was defined as the self-adhesive force (initial) to the adherend.
<Self-adhesiveness (after promotion test)>
The test piece and the adherend were prepared by the same method as the above-mentioned measurement of "self-adhesive force (initial)". The surface of the test piece on the self-adsorptive foam sheet side is attached to the surface of the adherend on the wallpaper side, and a load of 2 kgf is applied from the top of the test piece to crimp it with a roller. It was left for 3 hours. Then, it was left for 14 days in a constant temperature bath (manufactured by ESPEC, "CSH-111") adjusted to 60 ° C. and 80% RH (accelerated test). After 14 days, the bonded body of the test piece and the adherend was taken out from the constant temperature bath, left at 23 ° C. in a 50% RH environment for 3 hours, and then the end of the test piece was autographed (manufactured by Shimadzu Corporation, manufactured by Shimadzu Corporation). It was fixed to the upper chuck of "AG-IS"), the adherend was fixed to the lower chuck, and a 180 degree peeling test was carried out at a speed of 300 mm / min in a 23 ° C. and 50% RH environment. The peeling force (N / cm) at this time was defined as the self-adhesive force to the adherend (after the acceleration test).
<Adhesion stability>
In the above "self-adhesiveness (after acceleration test)" measurement, visually check whether the test piece immediately after being taken out from the constant temperature bath after the acceleration test is free from floating or peeling from the adherend, and based on the following criteria. evaluated.
A: Floating / peeling of the test piece from the adherend is not confirmed B: Floating / peeling of the test piece from the adherend is confirmed <Reworkability>
A part of the self-adsorptive foam sheet (acrylic resin) on the surface of the adherend after the above-mentioned "self-adhesive force (after acceleration test)" measurement (that is, the adherend after the self-adsorptive laminate is peeled off). ) Was visually confirmed and evaluated according to the following criteria.
A: No resin residue is confirmed on the surface of the adherend B: Resin residue is confirmed on the surface of the adherend

(Example 1)
<Preparation of composition for foam sheet>
In a mixing container, 100 parts (solid content: 55 parts) of acrylic resin latex (manufactured by Nippon Zeon, "Nipol LX874", glass transition temperature: -36 ° C, solid content concentration: 55%) and an epoxy-based cross-linking agent Add 1 part of (Japan Coating Resin Co., Ltd., "Ricabond EX-8", fatty acid polyglycidyl ether) and 4 parts of foam stabilizer (San Nopco Co., Ltd., "Nopco DC-100A", ammonium stearate) in this order. , A composition for a foamed sheet was obtained.
<Preparation of self-adsorptive laminate>
The composition for a foam sheet obtained as described above was stirred with a whisk, beaten so that the foaming ratio became 1.6 times, the stirring speed was further reduced, and stirring was continued for 5 minutes.
The foamed composition for foam sheet (foam) was coated on a wallpaper base material (manufactured by Lilycolor, "LB-9424") using an applicator. This was placed in a drying oven and held at 80 ° C. for 1.33 minutes, 120 ° C. for 1.33 minutes, and 140 ° C. for 1.33 minutes, dried and crosslinked, and a self-adsorbing foam sheet was placed on the substrate. A self-adsorptive laminated body (laminated sheet) comprising the above was obtained. The thickness of the self-adsorptive foam sheet was 200 μm.
Then, various evaluations were performed using the obtained self-adsorptive laminate. The results are shown in Table 1.

(Example 2)
A composition for a foam sheet and a self-adsorptive laminate were prepared in the same manner as in Example 1 except that the foaming ratio was changed to 2.0 times at the time of producing the self-adsorbent laminate, and evaluated in the same manner as in Example 1. Was done. The results are shown in Table 1.

(Comparative Example 1)
A composition for a foam sheet and a self-adsorptive laminate were prepared in the same manner as in Example 1 except that the foaming ratio was changed to 1.0 times at the time of producing the self-adsorbent laminate, and evaluated in the same manner as in Example 1. Was done. The results are shown in Table 1.

(Comparative Example 2)
A composition for a foam sheet and a self-adsorptive laminate were prepared in the same manner as in Example 1 except that the foaming ratio was changed to 2.5 times at the time of producing the self-adsorbent laminate, and evaluated in the same manner as in Example 1. Was done. The results are shown in Table 1.

(Comparative Example 3)
<Preparation of acrylic resin (polymer)>
A monomer mixture consisting of 64 parts of ethyl acrylate, 12 parts of 2-ethylhexyl acrylate, 12 parts of n-butyl acrylate, 9 parts of acrylonitrile, 2 parts of styrene and 1 part of acrylic acid in 27.0 parts of deionized water. In addition, 0.4 part of polyoxyethylene alkyl sulfate sodium (manufactured by Kao Co., Ltd .: Latemul E-118B) was mixed and stirred to obtain a monomeric emulsion.
Next, separately from the above, a glass reaction vessel equipped with a reflux condenser, a dropping funnel, a thermometer, a nitrogen inlet, and a stirrer was prepared, and 43.0 parts of deionized water and 43.0 parts of deionized water were prepared in the glass reaction vessel. 0.2 part of polyoxyethylene alkyl sodium sulfate was added, and the temperature was raised to 80 ° C. with stirring. Then, while maintaining 80 ° C., 0.3 part of ammonium persulfate dissolved in 5.7 parts of deionized water was added, and then the monomer emulsion obtained above was added over 4 hours. Was added gradually. After the addition was completed, stirring was continued for another 4 hours, and then the mixture was cooled to terminate the reaction to obtain a reaction mixture. The polymerization conversion at this time was approximately 100% (98% or more), and the obtained reaction mixture was adjusted to pH 5.0 with 5% aqueous ammonia, and 2.5 parts of polyoxyethylene lauryl ether (Kao). After adding Emargen 120), the mixture was concentrated to obtain a polymer latex having a solid content concentration of 55%.
<Preparation of composition for foam sheet>
In a mixing container, 100 parts of the above polymer latex, 3 parts of an epoxy-based cross-linking agent (manufactured by Japan Coating Resin Co., Ltd., "Ricabond EX-8", fatty acid polyglycidyl ether), and a wax agent (fatty acid portion having 16 or more and 34 or less carbon atoms). (Containing a fatty acid ester having a fatty acid ester) and 4 parts of a foam stabilizer (manufactured by Sannopco Co., Ltd., "Nopco DC-100A", ammonium stearate) were added in this order. Finally, a thickener (manufactured by Toagosei Co., Ltd., "Aron A-20L", sodium polyacrylate) was added to adjust the viscosity to 4250 mPa · s to obtain a composition for a foamed sheet.
<Preparation of self-adsorptive laminate>
The composition for a foam sheet obtained as described above was stirred with a whisk, beaten so that the foaming ratio became 1.6 times, the stirring speed was further reduced, and stirring was continued for 5 minutes.
The foamed composition for foam sheet (foam) was coated on a wallpaper base material (manufactured by Lilycolor, "LB-9424") using an applicator. This was placed in a drying oven and held at 80 ° C. for 1.33 minutes, 120 ° C. for 1.33 minutes, and 140 ° C. for 1.33 minutes, dried and crosslinked, and a self-adsorbing foam sheet was placed on the substrate. A self-adsorptive laminated body (laminated sheet) comprising the above was obtained. The thickness of the self-adsorptive foam sheet was 150 μm.
Then, various evaluations were performed using the obtained self-adsorptive laminate. The results are shown in Table 1. In the measurement of the self-adhesive force (initial and after the accelerated test), the test piece and the adherend were easily peeled off, and the peeling force could not be measured and the reworkability could not be evaluated.

From Table 1, it can be seen that in the self-adsorptive laminates of Examples 1 and 2, the unevenness-following property at the time of sticking, the adhesion stability for a long period of time, and the reworkability after long-term use can be arranged at a high level. On the other hand, from Table 1, in Comparative Example 1 in which the density and the 25% compressive strength are high, the unevenness followability at the time of pasting and the adhesion stability for a long period of time are lowered, and in Comparative Example 2 in which the density and the 25% compressive strength are low, the reworkability is achieved. In Comparative Example 3, which has a high 25% compressive strength, it can be seen that the unevenness followability at the time of pasting and the adhesion stability over a long period of time are deteriorated.

According to the present invention, it is possible to provide a self-adsorptive laminated body in which unevenness followability at the time of sticking, adhesion stability for a long period of time, and reworkability after long-term use are arranged side by side at a high level.

Claims (8)

A self-adsorptive laminate formed by laminating a base material and a self-adsorptive foam sheet made of an acrylic resin foam.
The self-adsorptive foam sheet is a self-adsorptive laminate having a density of 0.3 g / cm ³ or more and 0.7 g / cm ³ or less and a 25% compressive strength of 3 kPa or more and 15 kPa or less. The self-adsorptive laminate according to claim 1, wherein the self-adsorptive foam sheet has an average thickness of 0.05 mm or more and 1 mm or less. The self-adsorptive laminate according to claim 1 or 2, wherein the acrylic resin foam is formed of a crosslinked acrylic resin. The self-adsorptive laminate according to any one of claims 1 to 3, wherein the acrylic resin foam contains a defoaming agent. The self-adsorptive laminate according to any one of claims 1 to 4, wherein the self-adsorptive foam sheet has an unevenness follow-up rate of 30% or more and 90% or less. The self-adsorptive laminate according to any one of claims 1 to 5, wherein the self-adsorptive foam sheet has an initial self-adhesive force of 0.01 N / cm or more and 0.50 N / cm or less. The self-adsorptive laminate according to any one of claims 1 to 6, wherein the self-adhesive foam sheet has a self-adhesive force of 0.10 N / cm or more and 1.0 N / cm or less after the accelerated test. The self-adsorptive laminate according to any one of claims 1 to 7, which is used for sticking to an adherend surface having irregularities.