阅读说明：本技术 自吸附性发泡片用组合物和自吸附性发泡层叠片 (Composition for self-adsorptive foamed sheet and self-adsorptive foamed laminate sheet ) 是由 芦田真资 于 2020-03-23 设计创作，主要内容包括：本发明的目的在于提供一种自吸附性发泡片用组合物,其可用于得到具有优异的除气性且能够抑制耐候后在金属上的树脂残留的自吸附性发泡层叠片。本发明的自吸附性发泡片用组合物含有：以0.1质量％以上且20质量％以下的比例包含不饱和羧酸单体单元的聚合物、交联剂、相对于100质量份的上述聚合物为1.5质量份以上的高级脂肪酸盐。(The purpose of the present invention is to provide a composition for a self-adsorptive foamed sheet, which can be used to obtain a self-adsorptive foamed laminate sheet that has excellent outgassing properties and can suppress the resin residue on a metal after weathering. The composition for a self-adsorptive foamed sheet of the present invention comprises: the resin composition comprises a polymer containing an unsaturated carboxylic acid monomer unit in a proportion of 0.1 to 20% by mass, a crosslinking agent, and 1.5 parts by mass or more of a higher fatty acid salt per 100 parts by mass of the polymer.)

1. A composition for a self-adsorptive foamed sheet, comprising:

a polymer containing an unsaturated carboxylic acid monomer unit in a proportion of 0.1 to 20% by mass,

A crosslinking agent, and

1.5 parts by mass or more of a higher fatty acid salt per 100 parts by mass of the polymer.

2. The self-adsorptive foamed sheet composition according to claim 1, wherein the crosslinking agent is a carbodiimide-based crosslinking agent.

3. The composition for a self-adsorptive foamed sheet according to claim 1 or 2, wherein the polymer further contains a (meth) acrylate monomer unit in a proportion of 35% by mass or more and 99% by mass or less.

4. The self-adsorptive foamed sheet composition according to claim 3, wherein the (meth) acrylate monomer unit comprises an alkyl (meth) acrylate monomer unit having an alkyl group with a carbon number of 1 or more and 14 or less.

5. The self-adsorptive foamed sheet composition according to claim 3, wherein the (meth) acrylate monomer unit comprises an alkyl (meth) acrylate monomer unit having an alkyl group with a carbon number of 4 or more and 14 or less.

6. The composition for a self-adsorptive foamed sheet according to any one of claims 1 to 5, wherein the polymer does not have an N-methylol group.

7. The composition for a self-adsorptive foamed sheet according to any one of claims 1 to 6, further comprising an amphoteric surfactant.

8. The self-adsorptive foamed sheet composition according to any one of claims 1 to 7, wherein the higher fatty acid salt is a stearate.

9. A self-adsorptive foamed laminate sheet comprising a base material and a self-adsorptive foamed sheet formed using the composition for a self-adsorptive foamed sheet according to any one of claims 1 to 8.

Technical Field

The present invention relates to a composition for a self-adsorptive foamed sheet and a self-adsorptive foamed laminate sheet.

Background

In recent years, as an adhesive sheet to be used for adhering to a smooth adherend such as a window glass, a self-adsorptive foamed sheet (hereinafter, sometimes abbreviated as "foamed sheet") which is a sheet-like member having self-adsorptive property and formed of a foamed material having a plurality of fine pores has been used. The self-adsorptive foamed sheet is adhered not by adhesive bonding but by adsorbing an adherend through fine pores. Therefore, the self-adhesive foam sheet is easier to re-adhere than a conventional adhesive sheet using adhesive bonding, and is preferably used for applications such as wallpaper, posters, and stickers. When used for these applications, the self-priming foamed sheet is generally used in a form in which a self-priming foamed laminate sheet (hereinafter, may be abbreviated as "laminate sheet") is laminated with a base material. The self-adsorptive foamed laminate sheet can be advantageously used for the above-mentioned applications by applying decoration such as printing to the surface on the substrate side.

Further, in order to improve the performance of a self-adsorptive foamed laminate sheet, a composition for producing a foamed sheet constituting the laminate sheet (hereinafter referred to as "composition for self-adsorptive foamed sheet", and may be abbreviated as "composition for foamed sheet") has been improved.

For example, in recent years, self-adsorptive foamed laminates are often used outdoors. Therefore, for the self-adhesive foamed laminate sheet, it is required to suppress a part of the foamed sheet made of a resin from remaining on the surface of the adherend (i.e., suppress resin residue on the adherend after weathering) even when peeled from the adherend after long-term exposure to sunlight or rain.

In order to solve such a problem, patent document 1 proposes a composition for a foam sheet containing a polymer having a predetermined property and a crosslinking agent. Further, according to the laminate sheet having the foamed sheet formed from the composition for a foamed sheet of patent document 1, the resin can be suppressed from remaining on the glass as an adherend even after weather resistance.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2018/151274.

Disclosure of Invention

Problems to be solved by the invention

However, in recent years, due to diversification of applications of the laminate sheet, opportunities of using the laminate sheet as a sheet attached to not only glass but also metal have increased. Further, according to the studies of the present inventors, although the laminate sheet obtained by the above-described conventional techniques can suppress the residue of the resin on the glass after weathering, there is still room for improvement in sufficiently suppressing the residue of the resin on the metal (particularly, stainless steel (SUS)) after weathering.

In addition, the laminate sheet is required to have a property of easily removing air trapped between the foam sheet and the adherend when the surface on the foam sheet side is adsorbed to the adherend (i.e., excellent outgassing property). Further improvement in the outgassing property is also required.

Accordingly, an object of the present invention is to provide a self-adsorptive foamed laminate sheet having excellent outgassing properties and capable of suppressing the residue of a resin on a metal after weather resistance, and a composition for a self-adsorptive foamed sheet for obtaining the self-adsorptive foamed laminate sheet.

Means for solving the problems

The present inventors have conducted intensive studies in order to solve the above problems. Then, the present inventors have found that when a composition for a foam sheet containing a predetermined amount of a higher fatty acid salt or more, a predetermined polymer and a crosslinking agent is used to form a foam sheet, the outgassing property of a laminate sheet having the foam sheet can be improved, and the resin residue on a metal after weather resistance can be suppressed, and have completed the present invention.

That is, the present invention is directed to advantageously solve the above problems, and the composition for a self-adsorptive foamed sheet of the present invention is characterized by containing a polymer containing an unsaturated carboxylic acid monomer unit in a proportion of 0.1 to 20% by mass, a crosslinking agent, and 1.5 parts by mass or more of a higher fatty acid salt per 100 parts by mass of the polymer. As described above, if the foamed sheet is formed using the composition for a foamed sheet containing the polymer containing the unsaturated carboxylic acid monomer unit, the crosslinking agent, and the higher fatty acid salt in the above-described proportions, and the blending amount of the higher fatty acid salt with respect to the polymer is not less than the above-described value, the laminate sheet having the foamed sheet can exhibit excellent air release properties, and the resin can be inhibited from remaining on the metal even after the laminate sheet is exposed to sunlight or rain for a long time.

In addition, in the present invention, "comprising a monomer unit" means "comprising a structural unit derived from a monomer in a polymer obtained using the monomer".

In the present invention, the "higher fatty acid salt" means a salt formed from a higher fatty acid anion having 8 or more carbon atoms and a counter cation.

Here, in the composition for a self-adsorptive foamed sheet of the present invention, the crosslinking agent is preferably a carbodiimide-based crosslinking agent. When the composition for a foam sheet containing a carbodiimide-based crosslinking agent as a crosslinking agent is used, resin remaining on the metal after the laminate is weather-resistant can be further suppressed.

In the composition for a self-adsorptive foamed sheet of the present invention, the polymer preferably further contains a (meth) acrylate monomer unit in a proportion of 35% by mass or more and 99% by mass or less. When the composition for a foam sheet containing a polymer containing a (meth) acrylate monomer unit at the above ratio is used, a laminate sheet can be obtained in which a good self-adhesive force (adhesion force to an adherend) is maintained and resin residue on a metal after weather resistance is further suppressed.

In addition, in the present invention, "(meth) acrylate" means acrylate and/or methacrylate.

In the self-adsorptive foamed sheet composition of the present invention, the (meth) acrylate monomer unit preferably contains an alkyl (meth) acrylate monomer unit having an alkyl group with a carbon number of 1 to 14. The self-adhesive force of the laminate sheet can be improved by using a composition for a foam sheet comprising a polymer containing an alkyl (meth) acrylate monomer unit having an alkyl group and having 1 to 14 carbon atoms (hereinafter sometimes simply referred to as "C1-14 alkyl (meth) acrylate monomer unit").

In addition, in the present invention, "(meth) acrylic acid" means acrylic acid and/or methacrylic acid.

Further, in the present invention, the "carbon number of an alkyl group" of the alkyl (meth) acrylate monomer unit means the carbon number of an alkyl group bonded to a non-carbonyl oxygen atom.

In the self-adsorptive foamed sheet composition of the present invention, the (meth) acrylate monomer unit preferably contains an alkyl (meth) acrylate monomer unit having an alkyl group with a carbon number of 4 or more and 14 or less. The self-adhesive force of the laminate sheet can be further improved by using a composition for a foam sheet, which contains a polymer containing an alkyl (meth) acrylate monomer unit having an alkyl group and having 4 to 14 carbon atoms (hereinafter, sometimes simply referred to as "C4-14 alkyl (meth) acrylate monomer unit").

In the composition for a self-adsorptive foamed sheet of the present invention, the polymer preferably does not have an N-methylol group. When the composition for foam sheet containing a polymer having no N-methylol group is used, the formation of formaldehyde can be sufficiently suppressed when the composition for foam sheet is foamed and cured.

Further, the composition for a self-adsorptive foamed sheet of the present invention preferably further contains an amphoteric surfactant. If the composition for a foam sheet containing an amphoteric surfactant is used, the self-adhesive force of the laminate sheet does not excessively increase even after weather resistance, and the laminate sheet can be peeled off from the adherend with sufficient ease. In addition, the outgassing property of the laminate sheet can be further improved.

Here, in the composition for a self-adsorptive foamed sheet of the present invention, the higher fatty acid salt is preferably a stearate. If a composition for a sheet comprising a stearate as a higher fatty acid salt is used, the outgassing of the resulting laminated sheet can be further improved.

Further, the present invention has an object to advantageously solve the above problems, and the self-adsorptive foamed laminate of the present invention is characterized by having a base material and a self-adsorptive foamed sheet formed using any of the above compositions for self-adsorptive foamed sheets. The laminate sheet having the foamed sheet formed from the composition for a foamed sheet on a substrate has excellent outgassing property, and in addition, can suppress the resin from remaining on the metal even after long-term exposure to sunlight or rain.

Effects of the invention

According to the present invention, it is possible to provide a self-adsorptive foamed laminate sheet having excellent outgassing properties and capable of suppressing resin residues on a metal after weather resistance, and a composition for a self-adsorptive foamed sheet for obtaining the self-adsorptive foamed laminate sheet.

Drawings

Fig. 1 is a flowchart illustrating an example of a method for producing the self-adsorptive foamed laminate sheet of the present invention.

Fig. 2 is an explanatory view showing a schematic configuration of an evaluation device for evaluating the deaeration property of the self-adsorptive foamed laminate sheet in the examples and comparative examples.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

Here, the composition for a self-adsorptive foamed sheet of the present invention can be preferably used for obtaining a self-adsorptive foamed sheet which is a constituent of the self-adsorptive foamed laminate sheet of the present invention. The self-adsorptive foamed laminate sheet of the present invention further includes a self-adsorptive foamed sheet formed using the composition for a self-adsorptive foamed sheet of the present invention.

(self-adsorptive foam sheet composition)

The composition for a foam sheet of the present invention contains a polymer containing an unsaturated carboxylic acid monomer unit in a proportion of 0.1 to 20% by mass, a crosslinking agent, and a higher fatty acid salt, and optionally contains a solvent and other additives. Here, the amount of the higher fatty acid salt to be blended in the composition for a foam sheet of the present invention is 1.5 parts by mass or more per 100 parts by mass of the polymer.

Further, by forming a foam sheet on a substrate using the composition for a foam sheet of the present invention, a laminate sheet having excellent outgassing property and suppressed resin residue on a metal after weather resistance can be obtained.

< polymers >

The polymer used in the composition for a foam sheet of the present invention is a polymer containing an unsaturated carboxylic acid monomer unit in a proportion of 0.1 to 20% by mass. Further, the polymer forms a resin matrix in the obtained foamed sheet by foaming and crosslinking the composition for a foamed sheet.

< composition of Polymer >)

Here, the polymer contains unsaturated carboxylic acid monomer units in the above-mentioned ratio, and contains one or two or more monomer units other than the unsaturated carboxylic acid monomer units. Preferable examples of such monomer units other than the unsaturated carboxylic acid monomer unit include a (meth) acrylate monomer unit and an alkenyl aromatic monomer unit. Further, the polymer can contain a monomer unit (other monomer unit) other than the unsaturated carboxylic acid monomer unit, (meth) acrylate ester monomer unit, alkenyl aromatic monomer unit.

[ unsaturated carboxylic acid monomer Unit ]

The unsaturated carboxylic acid monomer unit is a structural unit derived from an unsaturated carboxylic acid monomer.

Specific examples of the unsaturated carboxylic acid monomer include α, β -ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; α, β -ethylenically unsaturated polycarboxylic acids such as itaconic acid, maleic acid, fumaric acid and the like; and α, β -ethylenically unsaturated polycarboxylic acid partial esters such as monomethyl itaconate, monobutyl maleate, monopropyl fumarate, and the like. In addition, monomers having a group that can be derived into a carboxylic acid group by hydrolysis or the like, such as maleic anhydride and itaconic anhydride, can also be used in the same manner. Among these, itaconic acid, acrylic acid and methacrylic acid are preferable, and itaconic acid is more preferable, from the viewpoints of reactivity with a crosslinking agent described later, stability of the polymer latex and cost.

The unsaturated carboxylic acid monomer may be used alone or in combination of two or more.

The proportion of the unsaturated carboxylic acid monomer unit in the polymer is required to be 0.1% by mass or more and 20% by mass or less, preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 1.5% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 2.5% by mass or less, based on 100% by mass of all the repeating units (all the monomer units) contained in the polymer. When the proportion of the unsaturated carboxylic acid monomer unit in the polymer is 0.1% by mass or more, the crosslinking reaction by the crosslinking agent described later can be sufficiently performed. As a result, the obtained foam sheet can be provided with sufficient strength, and resin residue on the metal after weather resistance of the laminate can be suppressed. On the other hand, when the proportion of the unsaturated carboxylic acid monomer unit in the polymer is 20% by mass or less, the viscosity of the polymerization system at the time of polymerization can be easily maintained in an appropriate range, and the self-adhesive force of the laminate sheet is not impaired by excessive crosslinking of the polymer.

[ (meth) acrylate monomer units ]

The (meth) acrylate monomer unit is a structural unit derived from a (meth) acrylate monomer. The polymer contains a (meth) acrylate monomer unit, and thus can impart flexibility to the foamed sheet obtained and can provide a laminated sheet having good self-adhesion.

The (meth) acrylate monomer is not particularly limited, and examples thereof include: alkyl (meth) acrylate monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, n-heptyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and n-dodecyl (meth) acrylate; alkoxyalkyl (meth) acrylate monomers such as 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, and ethoxymethyl (meth) acrylate.

One kind of the (meth) acrylate monomer may be used alone, or two or more kinds may be used in combination.

Here, the (meth) acrylate monomer is preferably an alkyl (meth) acrylate monomer, more preferably an alkyl (meth) acrylate monomer having C1-14 (meth) acrylate, and still more preferably an alkyl (meth) acrylate monomer having C4-14 (meth) acrylate, from the viewpoint of further improving the flexibility of the foamed sheet and further preferably ensuring the self-adhesive force of the laminate sheet.

Examples of the alkyl (meth) acrylate monomer having C1-14 include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, n-heptyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, and n-dodecyl methacrylate.

Examples of the alkyl (meth) acrylate monomer having C4-14 include n-butyl acrylate, sec-butyl acrylate, n-heptyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, n-octyl methacrylate, and n-dodecyl methacrylate.

Among these, n-butyl acrylate is preferable from the viewpoint of self-adhesion and cost.

The proportion of the (meth) acrylate ester monomer unit in the polymer is preferably 35% by mass or more, more preferably 40% by mass or more, further preferably 45% by mass or more, preferably 99% by mass or less, more preferably 95% by mass or less, and further preferably 90% by mass or less, based on 100% by mass of all the repeating units (all the monomer units) contained in the polymer. If the proportion of the (meth) acrylate monomer unit in the polymer is 35% by mass or more, the self-adhesion of the laminate can be sufficiently ensured. On the other hand, if the proportion of the (meth) acrylate monomer unit in the polymer is 99 mass% or less, the self-adhesive force of the laminate is not excessively increased. Therefore, the resin residue on the metal after the weather resistance of the laminate can be further suppressed.

The proportion of the C4-14 alkyl (meth) acrylate monomer unit in the polymer is preferably 35% by mass or more, more preferably 40% by mass or more, further preferably 45% by mass or more, particularly preferably 62% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and further preferably 75% by mass or less, based on 100% by mass of all the repeating units (all the monomer units) contained in the polymer. By setting the C4-14 alkyl (meth) acrylate monomer unit in the polymer to 35 mass% or more, the water resistance of the laminate sheet can be improved while sufficiently securing the self-adhesive force of the laminate sheet. Therefore, the resin residue on the metal after the weather resistance of the laminate can be further suppressed. On the other hand, if the proportion of the C4-14 alkyl (meth) acrylate monomer units in the polymer is 90 mass% or less, the self-adhesive force of the laminate is not excessively increased. Therefore, the resin residue on the metal after the weather resistance of the laminate can be further suppressed.

[ alkenyl aromatic monomer Unit ]

The alkenyl aromatic monomer unit is a structural unit derived from an alkenyl aromatic monomer.

Specific examples of the alkenyl aromatic monomer include styrene, α -methylstyrene, α -chlorostyrene, vinyltoluene, and divinylbenzene. Among these, styrene is preferred from the viewpoint of polymerizability and cost.

One kind of alkenyl aromatic monomer may be used alone, or two or more kinds may be used in combination.

The proportion of the alkenyl aromatic monomer unit in the polymer is preferably 1% by mass or more, more preferably 5% by mass or more, further preferably 10% by mass or more, particularly preferably 12% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, and particularly preferably 20% by mass or less, based on 100% by mass of all the repeating units (all the monomer units) contained in the polymer. If the ratio of the alkenyl aromatic monomer unit in the polymer is 1 mass% or more, water penetration into the foam sheet can be prevented based on the hydrophobicity of the alkenyl aromatic monomer unit, and the water resistance of the laminate sheet can be improved. Therefore, the resin residue on the metal after the weather resistance of the laminate can be further suppressed. On the other hand, if the ratio of the alkenyl aromatic monomer unit in the polymer is 50% by mass or less, the flexibility of the resulting foamed sheet can be sufficiently ensured, and a laminated sheet having good self-adhesion can be obtained.

[ other monomer units ]

The other monomer unit is a structural unit derived from another monomer copolymerizable with the above-mentioned monomer.

Examples of the other monomer include a conjugated diene monomer, an α, β -ethylenically unsaturated polycarboxylic acid full ester monomer, a vinyl cyanide monomer, a carboxylic acid unsaturated alcohol ester monomer, an olefin monomer, and a monomer having another functional group. These monomers may be used alone or in combination of two or more. Specific examples of such other monomers are not particularly limited, and monomers described in, for example, international publication No. 2018/151274 can be used.

In addition, the polymer preferably does not have an N-methylol group from the viewpoint of sufficiently suppressing the generation of formaldehyde when the composition for a foam sheet is foamed and cured. More specifically, it is preferable that the polymer does not contain a monomer unit having an N-methylol group.

Examples of the monomer having an N-methylol group include N-methylolacrylamide and N-methylolmethacrylamide.

< preparation method of Polymer >)

The polymerization method for obtaining the polymer is not particularly limited, and may be any of solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization, and the like, or other methods. The kind and amount of the polymerization initiator, emulsifier, dispersant and the like used in the polymerization are not particularly limited. In the polymerization, the method of adding the monomer, the polymerization initiator, the emulsifier, the dispersant and the like is also not particularly limited. Further, the polymerization temperature, pressure, stirring conditions and the like are also not limited.

The polymer may be used in a solid state, but if it is used in a state of a polymer-containing latex (polymer latex) such as a latex obtained by emulsion polymerization or a latex obtained by post-emulsifying a polymer, handling at the time of mixing with a crosslinking agent, a higher fatty acid salt, or the like is easy, and the obtained composition for a foam sheet is also easily foamed.

< Properties of Polymer >

Here, the dissolution parameter (SP value) of the polymer is preferably 9.7 (cal/cm)³)^1/2(19.9(MPa)^1/2) Hereinafter, more preferably 9.6 (cal/cm)³)^1/2(19.7(MPa)^1/2) Hereinafter, more preferably 9.0 (cal/cm)³)^1/2(18.4(MPa)^1/2) The following. If the polymer has a solubility parameter of 9.7 (cal/cm)³)^1/2Hereinafter, it becomes easy to manufacture a laminate sheet having an appropriate self-adhesive force. Further, the water resistance of the laminate sheet can be improved, and the resin remaining on the metal after the weather resistance of the laminate sheet can be further suppressed.

The lower limit of the solubility parameter of the polymer is not particularly limited, but is usually 8.5 (cal/cm)³)^1/2(17.4(MPa)^1/2) The above.

In addition, the dissolution parameter of the polymer can be calculated using the radical contribution method of Hoy.

The glass transition temperature of the polymer is preferably-10 ℃ or lower, more preferably-13 ℃ or lower, still more preferably-17 ℃ or lower, and particularly preferably-20 ℃ or lower. When the glass transition temperature of the polymer is-10 ℃ or lower, the self-adhesive force of the laminate sheet can be sufficiently ensured, and the laminate sheet and the adherend can be well adhered to each other, and the penetration of moisture into the interlayer between the adherend and the laminate sheet can be prevented. Therefore, the resin residue on the metal after the weather resistance of the laminate can be further suppressed.

The lower limit of the glass transition temperature of the polymer is not particularly limited, but is preferably-40 ℃ or higher from the viewpoint of sufficiently suppressing the resin residue on the metal after weathering of the laminate

The glass transition temperature of the polymer can be measured by the method described in examples of the present specification.

The polymer is not particularly limited, and can be used for the preparation of the composition for a foam sheet as a polymer latex, as described above. The solid content concentration of the polymer latex is preferably 40% by mass or more, more preferably 45% by mass or more, further preferably 50% by mass or more, particularly preferably 52% by mass or more, preferably 70% by mass or less, and more preferably 58% by mass or less, from the viewpoint of maintaining the density of the foamed sheet to be obtained.

< crosslinking agent >

The crosslinking agent is not particularly limited as long as it is a crosslinking agent capable of forming a crosslinked structure with the polymer (particularly, the unsaturated carboxylic acid monomer unit of the polymer). Examples of such a crosslinking agent include carbodiimide-based crosslinking agents; an epoxy-based crosslinking agent; an oxazoline-based crosslinking agent; polyfunctional isocyanate crosslinking agents such as toluene diisocyanate, trimethylolpropane toluene diisocyanate, diphenylmethane triisocyanate and the like; a metal salt-based crosslinking agent; a metal chelate-based crosslinking agent; peroxide-based crosslinking agents, and the like. Among these, a carbodiimide-based crosslinking agent is preferably used, and particularly, a compound having 2 or more carbodiimide groups in one molecule is more preferably used.

The carbodiimide-based crosslinking agent can be synthesized by a known method, and a commercially available product can be used. Examples of commercially available carbodiimide-based crosslinking agents include "DICNAL (registered trademark) HX" manufactured by DIC corporation and "CARBODILITE (registered trademark)" manufactured by riqing textile chemical corporation. In the case of synthesizing a carbodiimide-based crosslinking agent, for example, a polycarbodiimide compound as a carbodiimide-based crosslinking agent can be obtained by subjecting a polyisocyanate to a decarboxylation condensation reaction in the presence of a carbodiimidization catalyst.

The carbodiimide-based crosslinking agent forms a crosslinked structure in or between molecules of the polymer by a reaction between a carbodiimide group contained therein and an unsaturated carboxylic acid monomer unit in the polymer. The carbodiimide-based crosslinking agent has an excellent crosslinking effect particularly at low temperatures, has an appropriate self-adhesive force, and can form a foamed sheet having excellent strength. Therefore, if the composition for a foam sheet containing a carbodiimide-based crosslinking agent as a crosslinking agent is used, the resin residue on the metal after the weather resistance of the laminate can be further suppressed.

In the present invention, it is preferable not to use a crosslinking agent such as a melamine-formaldehyde resin, a urea-formaldehyde resin, or a phenol resin, which causes generation of formaldehyde.

Here, the amount of the crosslinking agent to be blended in the composition for a foam sheet is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, further preferably 2 parts by mass or more, preferably 20 parts by mass or less, and more preferably 10 parts by mass or less, based on 100 parts by mass of the polymer. When the amount of the crosslinking agent is within the above range, a foamed sheet having moderate strength and elasticity can be obtained. Furthermore, the self-adhesive force of the laminate sheet can be ensured and the resin residue on the metal of the laminate sheet (particularly after weather resistance) can be sufficiently suppressed.

< salts of higher fatty acids >

The higher fatty acid salt is a salt formed from a higher fatty acid anion having 8 or more carbon atoms and a counter cation as described above. Here, the higher fatty acid salt is a substance that can function as a foam stabilizer. It is also presumed that by foaming and curing a composition for a foam sheet containing a predetermined amount or more of a higher fatty acid salt in relation to the polymer to form a foam sheet, the continuous foam structure and water resistance of the foam sheet are improved, and the outgassing property of a laminate sheet having the foam sheet is improved, and the resin residue on the metal after weather resistance can be suppressed.

The higher fatty acid salt may be used alone or in combination of two or more.

The higher fatty acid anion constituting the higher fatty acid salt is derived from a higher fatty acid having 8 or more carbon atoms.

The number of carbon atoms of the higher fatty acid anion (and the higher fatty acid) is desirably 8 or more, preferably 10 or more, more preferably 14 or more, particularly preferably 16 or more, preferably 25 or less, and more preferably 20 or less, as described above. When the number of carbon atoms of the higher fatty acid anion is less than 8, resin residue on the metal after weather resistance of the laminate sheet cannot be suppressed. On the other hand, by setting the number of carbon atoms of the higher fatty acid anion to 25 or less, the outgassing property of the laminate sheet can be further improved.

Specific examples of the higher fatty acid having 8 or more carbon atoms include caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, decenoic acid, undecylenic acid, 2-ethylhexanoic acid, isononanoic acid, 3,5, 5-trimethylhexanoic acid, tridecanoic acid, tetramethylnonanoic acid, myristic acid, pentadecanoic acid, palmitic acid, stearic acid, isostearic acid, 12-hydroxystearic acid, arachidonic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, gadoleic acid, erucic acid, nervonic acid, linoleic acid, elaidic acid, linolenic acid, arachidonic acid, 2-hexyldecanoic acid, coconut oil fatty acid (including cured product and semi-cured product), palm kernel oil fatty acid (including cured product and semi-cured product), and mixtures thereof, Tallow fatty acid (including cured product and semi-cured product). These may be used alone or in combination of two or more.

The counter cation constituting the higher fatty acid salt is not particularly limited, and may be ammonium ion (NH)⁴⁺) Calcium ion (Ca)²⁺) Potassium ion (K)⁺) Sodium ion (Na)⁺) And the like. These may be used alone or in combination of two or more.

Here, as the higher fatty acid salt, a stearate salt or a tallow fatty acid salt is preferable from the viewpoint of further improving the degassing property of the laminate sheet and suppressing resin residue on the metal after weather resistance in a well-balanced manner. Further, from the viewpoint of further improving the outgassing property of the laminate sheet, a stearate is more preferable, and ammonium stearate is further preferable.

The amount of the higher fatty acid salt to be blended in the composition for a foam sheet is desirably 1.5 parts by mass or more, preferably 2.0 parts by mass or more, more preferably 3.0 parts by mass or more, further preferably 3.6 parts by mass or more, preferably 10.0 parts by mass or less, more preferably 7.0 parts by mass or less, and further preferably 5.0 parts by mass or less, based on 100 parts by mass of the polymer. When the amount of the higher fatty acid salt blended is less than 1.5 parts by mass relative to 100 parts by mass of the polymer, the outgassing property of the laminate sheet is lowered, and further, the resin residue on the metal after weather resistance cannot be sufficiently suppressed. On the other hand, if the amount of the higher fatty acid salt blended is 10.0 parts by mass or less with respect to 100 parts by mass of the polymer, the outgassing of the laminate sheet can be further improved.

< solvent >

The solvent that can be optionally contained in the composition for a foam sheet of the present invention is not particularly limited, and water is preferred. Here, in the case of using water as a solvent, the water contained in the composition for a foam sheet can be water from, for example, a polymer latex.

< other additives >

The composition for a foam sheet of the present invention may optionally contain various additives for the purpose of improving processability in the production process of the foam sheet and the laminate sheet and improving the performance of the foam sheet and the laminate sheet obtained. Examples of such additives include foam regulators (other foam regulators) other than the above-mentioned higher fatty acids, foaming aids, thickeners, fillers, preservatives, mildewcides, gelling agents, flame retardants, antioxidants, pigments, dyes, thickeners, conductive compounds, water-resistant agents, oil-resistant agents, and the like. Specific examples of the other additives are not particularly limited, and known additives, for example, the additives described in international publication No. 2016/147679, can be used.

Here, the composition for a foam sheet of the present invention preferably contains an amphoteric surfactant as another foam stabilizer. Further, as the amphoteric surfactant, a carboxylic acid type amphoteric surfactant is preferable, lauryl dimethylamino acetic acid betaine and stearyl dimethylamino acetic acid betaine are more preferable, and lauryl dimethylamino acetic acid betaine is further preferable. When the composition for a foam sheet containing an amphoteric surfactant is used, the self-adhesive force of the laminate sheet after weather resistance is not excessively increased, and the laminate sheet can be sufficiently easily peeled from an adherend. In addition, the outgassing of the laminate sheet can be further improved.

The amphoteric surfactant may be used alone or in combination of two or more.

The amount of the amphoteric surfactant to be blended in the composition for a foam sheet is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, further preferably 0.9 part by mass or more, preferably 5.0 parts by mass or less, more preferably 3.0 parts by mass or less, and further preferably 2.0 parts by mass or less, per 100 parts by mass of the polymer. If the blending amount of the amphoteric surfactant is 0.1 parts by mass or more per 100 parts by mass of the polymer, it is possible to sufficiently suppress an excessive increase in self-adhesive force of the laminate after weather resistance and further improve the outgassing property of the laminate. On the other hand, if the blending amount of the amphoteric surfactant is 5.0 parts by mass or less with respect to 100 parts by mass of the polymer, the water resistance of the laminate sheet can be secured, and accidental peeling of the laminate sheet from an adherend after weather resistance can be sufficiently prevented.

The ratio of the amount of the amphoteric surfactant to the amount of the higher fatty acid salt to be blended in the composition for a foam sheet of the present invention is not particularly limited, and the value obtained by dividing the amount of the amphoteric surfactant by the amount of the higher fatty acid salt to be blended (amphoteric surfactant/higher fatty acid salt) is preferably 0.05 or more, more preferably 0.1 or more, further preferably 0.2 or more, particularly preferably 0.25 or more, preferably 1 or less, more preferably 0.8 or less, and further preferably 0.5 or less. If the value of the amphoteric surfactant/higher fatty acid salt is within the above range, the self-adhesion of the weather-resistant laminate can be more well controlled and the outgassing of the laminate can be more well improved.

(self-adsorptive foamed laminate sheet)

The laminate sheet of the present invention has a foamed layer formed from a foamed sheet obtained using the composition for a foamed sheet of the present invention and a base material as a support layer for supporting the foamed layer. The foam sheet may be formed directly on the base material, or may be formed on the base material with an arbitrary layer interposed therebetween.

< self-adsorptive foamed sheet >

The self-adsorptive foamed sheet forming the foamed layer in the laminate sheet of the present invention is formed by crosslinking and foaming the composition for a foamed sheet of the present invention.

The density of the self-adsorptive foamed sheet is not particularly limited, but is preferably 0.1g/cm³Above and 1.0g/cm³Hereinafter, more preferably 0.3g/cm³Above and 0.8g/cm³Hereinafter, more preferably 0.5g/cm³Above and 0.7g/cm³The following. If the density of the foamed sheet is 0.1g/cm³As described above, the strength of the foamed sheet can be secured, and if it is 1.0g/cm³Hereinafter, the resin residue on the metal can be sufficiently suppressed while ensuring sufficient outgassing of the laminate sheet.

The density of the foamed sheet can be calculated by the method described in the examples of the present specification.

The thickness of the foamed sheet is preferably 0.03mm or more, more preferably 0.05mm or more, further preferably 0.1mm or more, preferably 3mm or less, more preferably 1mm or less, further preferably 0.5mm or less, and particularly preferably 0.2mm or less. When the thickness of the foam sheet is 0.03mm or more, the mechanical strength of the foam sheet and the laminate sheet can be sufficiently ensured. On the other hand, if the thickness of the foamed sheet is 3mm or less, a laminated sheet excellent in degassing property and repeated adhesion property (repeated handling property) can be obtained.

< substrate >

The base material in the laminate sheet of the present invention is not particularly limited as long as it can support the above-mentioned foam sheet, and known base materials such as paper base materials, synthetic paper base materials, and plastic sheet base materials can be used.

The thickness of the base material is not particularly limited, and may be, for example, 10 μm or more and 200 μm or less.

< paper substrate >)

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

< synthetic paper substrate >)

Examples of the synthetic paper substrate include a sheet-like substrate formed by converting a surface layer into paper by a combination of a thermoplastic resin and an inorganic filler.

< Plastic substrate >)

Examples of the plastic substrate include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; a polystyrene-based resin; a polyvinyl chloride resin; an acrylic resin; a polycarbonate-based resin; a polyamide resin; fluorine-based resins such as polytetrafluoroethylene; and a sheet-like base material made of a mixture or laminate of these resins.

< method for producing self-adsorptive foamed laminate sheet >

An example of a method for producing the laminate sheet of the present invention will be described below.

Fig. 1 shows a flowchart for explaining an example of the method S10 for producing a laminated sheet (hereinafter, may be abbreviated as "production method S10"). As shown in fig. 1, the production method S10 includes a composition production step S1, a foaming step S2, and a sheet forming step S3 in this order. Hereinafter, various steps will be described.

< composition production Process S1>

The composition preparation step S1 is a step of preparing a composition for a self-adsorptive foamed sheet.

Specifically, in the composition preparation step S1, a composition for a foam sheet can be prepared by mixing a predetermined polymer, a crosslinking agent, a higher fatty acid salt, and a solvent and other additives used as needed as essential components by any method.

For example, in the case of using a polymer latex in the preparation of the composition for a foam sheet, a crosslinking agent, a higher fatty acid salt, and other additives optionally used may be added to the polymer latex and mixed by a known method.

In the case where a solid polymer is used without using a solvent in the preparation of the composition for foam sheet, the solid polymer, the crosslinking agent, the higher fatty acid salt, and optionally other additives may be mixed by a known method (for example, using a known roll, a henschel mixer, a kneader, or the like).

Here, the viscosity of the composition for a foam sheet containing a solvent (for example, in the form of an emulsion or a dispersion) is preferably 1000mPa · s or more and 10000mPa · s or less, more preferably 2000mPa · s or more and 10000mPa · s or less, and further preferably 3500mPa · s or more and 5500mPa · s or less. When the viscosity of the composition for a foam sheet is 1000MPa · s or more, it is possible to prevent the occurrence of liquid dripping and to make it difficult to control the thickness when a foam formed from the composition for a foam sheet is applied to a substrate to form a foam sheet. On the other hand, if the viscosity of the composition for a foam sheet is 10000MPa · s or less, it is not difficult to control the expansion ratio by mechanical foaming when forming a foam sheet.

The viscosity of the composition for a foam sheet can be calculated by the method described in examples of the present specification.

< foaming Process S2>

The foaming step S2 is a step of foaming the composition for a foam sheet to obtain a foam of the composition for a foam sheet.

Specifically, in the foaming step S2, the composition for a foam sheet prepared in the composition preparation step S1 is foamed to obtain a foam in an uncured (uncrosslinked) state. Here, when the composition for a foam sheet is in the form of an emulsion or a dispersion, a foam emulsion or a foam dispersion can be obtained.

As a method of foaming, mechanical foaming is generally employed. The expansion ratio can be appropriately adjusted, and is usually 1.2 times or more and 5 times or less, preferably 1.5 times or more and 4 times or less. The mechanical foaming method is not particularly limited, and can be performed by mixing a certain amount of air into an emulsion or dispersion of the composition for a foam sheet and stirring the mixture continuously or batchwise by an oxter mixer (OAKES mixer), a foam stirrer, or the like. The foaming emulsion or foaming dispersion thus obtained becomes a paste.

The mechanical foaming forms fine pores, and a foamed sheet having excellent air release properties can be obtained by the sheet-forming step S3 described later. Further, when the expansion ratio is 1.2 times or more, the degassing property can be prevented from being lowered, and when the expansion ratio is 5 times or less, the strength of the foamed sheet can be prevented from being lowered.

< Tablepharization Process S3 >)

The sheet forming step S3 is a step of forming the foam into a sheet and then performing a crosslinking reaction of the foam to produce a foamed sheet.

In the sheet-forming step S3, the method for molding the foam produced in the foaming step S2 into a sheet is not particularly limited. A preferable method is, for example, a method of coating a desired substrate with a foam and molding the foam into a sheet. In this manner, if the foam is coated on a desired substrate and the crosslinking reaction is allowed to proceed, a laminate sheet in which the foam sheet is directly provided on the substrate can be obtained.

Alternatively, the foam may be coated on a releasable sheet (e.g., a release-resistant engineering paper) instead of the base material. When the coating of the foam is performed on the releasable sheet and the crosslinking reaction is allowed to proceed, a laminate in which the foam sheet is directly provided on the releasable sheet can be obtained. The release sheet is peeled from the foamed sheet of the laminate, whereby a foamed sheet can be obtained alone (as an independent film).

As a method for applying the foam onto a substrate or a releasable sheet (hereinafter, these may be collectively referred to as "substrate or the like"), a commonly known coating apparatus such as a coater, a bar coater, a roll coater, a reverse roll coater, a screen coater, a knife coater, a deflection angle wheel coater or the like can be used.

As a method for crosslinking the foam coated in a sheet form on a substrate or the like, a method of drying the foam by heating is preferable. The method of heating and drying is not particularly limited as long as it is a method capable of drying and crosslinking the foam applied to the substrate or the like, and a known drying oven (for example, a hot air circulation type oven, a hot oil circulation hot air chamber, a far infrared heater chamber) can be used. The drying temperature can be, for example, 60 ℃ or higher and 180 ℃ or lower. It is preferable that the drying is not performed at a constant temperature, but performed in a multistage manner in which the drying is performed from the inside at a low temperature in the initial stage of the drying and sufficiently performed at a higher temperature in the latter stage of the drying.

The properties (density, thickness, hardness, etc.) of the foamed sheet can be adjusted by changing, for example, the mixing ratio of the bubbles, the composition of the composition for the foamed sheet, the solid content concentration, the conditions of drying and crosslinking, and the like.

The laminate sheet obtained through the above steps S1 to S3 is not particularly limited, and for example, the laminate sheet can be processed into a size that is easy to use by attaching a spacer film to a surface having self-adsorptive properties (i.e., a surface on the foam sheet side), winding the laminate sheet by a winder, and cutting the laminate sheet into pieces, such as punching and slicing.

< uses of the laminate >

The laminate sheet of the present invention can be subjected to printing on the substrate surface thereof by, for example, offset printing, seal printing, flexographic printing, screen printing, gravure printing, laser printing, thermal transfer printing, inkjet printing, or the like.

The laminate sheet having a printed surface on the substrate can be advantageously used for outdoor applications such as sales promotion cards, so-called POP cards (posters, stickers, advertisement displays, etc.), post office POPs (insert labels, etc.), road signs (funeral, home display places, etc.), signboards (entrance prohibition, forest road construction, etc.), and the like.

Examples

The present invention will be described in further detail with reference to examples below, but the present invention is not limited to these examples. Unless otherwise specified, "part" and "%" used herein are based on mass.

In the examples and comparative examples, the dissolution parameter and glass transition temperature of the polymer, the viscosity of the composition for a foamed sheet, the density of the foamed sheet, and the outgassing property of the laminate sheet, the self-adhesion to glass (initial and after weather resistance), the self-adhesion to SUS (initial and after weather resistance), the resin residue on glass after weather resistance, and the resin residue on SUS after weather resistance were measured or evaluated by the following methods.

< dissolution parameters of Polymer >

The dissolution parameter (SP value) of the polymer was calculated by the radical contribution method of Hoy.

< glass transition temperature of Polymer >

The polymer latex was applied to a polyethylene terephthalate film having a thickness of 50 μm using a 250 μm coater, and dried at room temperature for 24 hours to obtain a film formed on the polyethylene terephthalate film. The glass transition temperature (. degree.C.) was measured using a differential scanning calorimeter (manufactured by Hitachi Kagaku K.K.' DSC 7000X) under conditions of a measurement temperature of-50 ℃ to 160 ℃ inclusive and a temperature rise rate of 10 ℃ per minute in accordance with JIS K7121 using a film formed on the polyethylene terephthalate film (excluding the polyethylene terephthalate film) as a sample.

< viscosity of composition for foam sheet >

The viscosity of the composition for a foam sheet was measured at 23 ℃ using a B-type viscometer (RION co., Ltd, viscotiter VT-06).

< Density of foamed sheet >

After the laminate was produced, test pieces each having a size of 20cm × 20cm were prepared. Accurately weighing the mass of the cut test piece: xg, in addition, the mass of the substrate cut into 20cm by 20cm was accurately weighed: yg. Then, the thicknesses of the laminate sheet and the base material produced were measured by a thickness meter, respectively, and the thickness of the base material was subtracted from the thickness of the laminate sheet, thereby obtaining the thickness of the foam sheet: tcm. At this time, the thickness value was calculated from the average value at the time of measurement 5. The measured values of X, Y and T were substituted into the following formula to calculate the density of the foamed sheet.

Density (g/cm)³)＝(X-Y)/(T×20×20)

< outgassing of laminate sheet >

< evaluation device >

The evaluation of the air release property was performed using the evaluation apparatus 100 shown in fig. 2. The evaluation apparatus 100 shown in fig. 2 is an apparatus for evaluating the outgassing property of a laminated sheet 50 laminated by a foam sheet 51 and a base material 52, and includes: the sample-fixing plate 10 includes a through-hole 11, and a gas-pumping mechanism 40 for pumping air as a gas at a constant pressure from the other surface side (upper side in fig. 2) to the one surface side (lower side in fig. 2) of the sample-fixing plate 10 through the through-hole 11.

The gas pressure-feeding mechanism 40 includes a syringe 20 and a hammer 30, and the tip of the syringe 20 is connected to the through hole 11 of the sample fixing plate 10 on the other surface side of the sample fixing plate 10. The syringe 20 further includes: a needle 21 having a tip facing a vertically lower side (lower side in fig. 2), connected to the sample-fixing plate 10, and inserted and fixed into the through-hole 11 of the sample-fixing plate 10; a cylindrical outer cylinder 22 having a tip (lower end in fig. 2) connected to the through hole 11 via a needle 21; and a piston 23 that penetrates the outer cylinder 22 from the rear end side of the outer cylinder 22.

Further, the hammer 30 is attached to a flange provided at the rear end (upper end in fig. 2) of the piston 23.

In the gas pressure-feeding mechanism 40 having the above-described configuration, the piston 23 is pressed into the outer cylinder 22 by the weight of the piston 23 and the hammer 30, and the air in the outer cylinder 22 is pressure-fed to one surface side (the foam sheet 51) of the sample fixing plate 10 at a constant pressure via the needle 21 and the through hole 11.

In the evaluation apparatus 100 having the above-described configuration, for example, after the laminated sheet 50 is attached to the surface of the sample fixing plate 10 to which the needle 21 is fixed (the side opposite to the needle 21 side) so as to cover the through hole 11 (step (a)), the piston 23 to which the hammer 30 is attached is inserted to a position at a distance L from the tip, the outer cylinder 22 is connected to the needle 21, and the time required for the piston 23 to advance by the distance L due to the self weight of the piston 23 and the hammer 30 is measured (step (B)), whereby the deaeration ability of the laminated sheet 50 can be evaluated. That is, when the air in the outer cylinder 22 is pushed out from the through hole 11 at a constant pressure by the weight of the piston 23 and the weight 30, if the distance L is made constant and the amount of air pushed out from the inner cylinder 22 is made constant, the time for advancing the distance L becomes longer for the laminate sheet 50 having low outgassing property, and the time for advancing the distance L becomes shorter for the laminate sheet 50 having high outgassing property. Therefore, the outgassing performance of the laminate sheet 50 can be quantitatively evaluated from the time required for the piston 23 to advance the distance L. Further, since the evaluation can be performed under the condition that the amount and pressure of the air to be pressure-fed are constant, the air deaeration performance can be evaluated with high repeatability. Further, since the evaluation can be performed in a state where the laminate sheet 50 is attached to the sample fixing plate 10, the outgassing property of the laminate sheet 50 in a state where it is attached to the adherend can be accurately evaluated.

Further, as the sample fixing plate 10, a transparent polycarbonate plate (50 mm. times.50 mm) having a thickness of 1mm was used, as the syringe 20, a glass syringe having a capacity of 2mL and having a metal syringe needle having a diameter of 2mm was used, and as the hammer 30, a hammer having a weight of 30g attached to the piston 23 by a double-sided tape was used.

< evaluation step >)

After the laminate sheet was produced, the laminate sheet was cut into a size of 40mm × 40mm to obtain a sample to be evaluated.

Then, the surface of the prepared sample on the foam sheet side is attached to the surface of the sample fixing plate 10 on which the needle 21 is fixed (the side opposite to the needle 21 side) so as to cover the through hole 11 and prevent air from entering (step (a)), and then the piston 23 to which the hammer 30 is attached is inserted to the position where the scale of the outer cylinder 22 is 2mL, and the outer cylinder 22 and the needle 21 are connected. Then, the hand is removed from hammer 30 and piston 23, and the time required for piston 23 and hammer 30 to fall completely by their own weight (that is, 2mL of air is fed under pressure) is measured (step (B)). This measurement operation was repeated 3 times, and the average value of the measurement time was calculated. The smaller the value, the more excellent the degassing property of the laminate sheet.

< self-adhesion of laminate to glass (initial stage) >

After the production of the laminate, test pieces were prepared which were cut into 125mm × 25mm pieces. The surface of the test piece on the foam sheet side was bonded to a glass plate having a smooth surface, pressed from the test piece by a 2kgf load roll, and left to stand at 23 ℃ under 50% RH for 1 hour. Then, the end of the test piece was fixed to an upper chuck of an autograph (product of Shimadzu corporation, "AG-IS"), and a glass plate was fixed to a lower chuck, and a 180-degree peel test was performed at a speed of 300 mm/min in an environment of 23 ℃ and 50% RH. The test force (N/cm) at this time was defined as the self-adhesion force to glass (initial stage).

< self-adhesion of laminate to glass (after weathering)

After the production of the laminate, test pieces were prepared which were cut into 125mm × 25mm pieces. The surface of the test piece on the foam sheet side was bonded to a glass plate having a smooth surface, and the test piece was pressure-bonded thereto with a 2kgf load roll. Then, the glass plate to which the test piece was bonded was mounted on a test piece holder, and a discharge voltage of 50V and a discharge current of 60A were set with a daylight Carbon arc lamp weather resistance tester (product of SUGA tester, "well-SUN-HC · B") having a daylight Carbon arc (Ultra Long Life Carbon 4) light source, and the weather resistance acceleration treatment was performed for 500 hours under a condition of a black panel temperature of 63 ℃. The surface spray (simulated rainfall) time was 18 minutes/2 hours (a cycle of 18 minutes with surface spray and 102 minutes without surface spray was repeated). The test piece subjected to the weather resistance acceleration treatment was left in an atmosphere of 23 ℃ and 50% RH for one day in a state of being stuck to a glass plate. Then, the end of the test piece was fixed to an upper chuck of an autograph (product of Shimadzu corporation, "AG-IS"), and a glass plate was fixed to a lower chuck, and a 180-degree peel test was performed at a speed of 300 mm/min in an environment of 23 ℃ and 50% RH. The test force (N/cm) at this time was regarded as the self-adhesion force to glass (after weathering).

< self-adhesion of laminate to SUS (initial stage) >

The same operation as "self-adhesion (initial stage) of the laminate sheet to glass" was carried out except that an SUS plate ("SUS 304 BA", the same applies hereinafter) was used instead of the glass plate, and the self-adhesion (initial stage) to SUS was measured.

< self-adhesion of laminate to SUS (after weather resistance) >

The same procedure as "self-adhesion of laminate to glass (after weathering)" was carried out except that an SUS plate was used instead of the glass plate, and the self-adhesion to SUS (after weathering) was measured.

< resin residue on glass after weather resistance >

The glass plate after the "self-adhesion of the laminate to glass (after weathering resistance)" was measured (that is, the glass plate after the laminate was peeled off) was evaluated by visually confirming whether or not a part (resin) of the foam sheet remained on the surface thereof according to the following criteria.

A: no resin residue was observed on the surface of the glass plate

B: resin residue was observed on the surface of the glass plate

< resin residue on SUS after weather resistance >

The SUS plate after the "self-adhesion (after weathering resistance) of the laminate to SUS" measurement (that is, the SUS plate after the laminate is peeled) was evaluated by visually confirming whether or not a part (resin) of the foamed sheet remains on the surface thereof according to the following criteria.

A: no resin residue was observed on the surface of SUS plate

B: resin residue was observed on the surface of SUS plate

(example 1)

< preparation of Polymer >

A monomer emulsion was obtained by mixing and stirring 29.0 parts of deionized water, a monomer mixture composed of 70 parts of n-butyl acrylate and 14 parts of methyl methacrylate as (meth) acrylate monomers, 14 parts of styrene as an alkenyl aromatic monomer, 2 parts of itaconic acid as an unsaturated carboxylic acid monomer, 0.4 part of sodium dodecylbenzenesulfonate ("nepelex (registered trademark) G15" manufactured by kaowang), and 0.5 part of polyoxyethylene lauryl ether ("EMULGEN (registered trademark) 120" manufactured by kaowang.

Next, separately from the above, a glass reaction vessel having a reflux condenser, a dropping funnel, a thermometer, a nitrogen gas blowing port and a stirrer was prepared, and 43.0 parts of deionized water, 0.04 parts of sodium dodecylbenzenesulfonate (manufactured by kao corporation, "neplex G15") and 0.06 parts of polyoxyethylene lauryl ether (manufactured by kao corporation, "EMULGEN 120") were charged into the glass reaction vessel, and the temperature was raised to 80 ℃ while stirring. Further, 0.3 part of ammonium persulfate dissolved in 5.7 parts of deionized water was added while maintaining 80 ℃, and then the monomer emulsion obtained above was slowly added over 4 hours. After the completion of the addition, the reaction mixture was stirred for 4 hours and then cooled to terminate the reaction. The polymerization conversion at this time was almost 100% (98% or more), and the pH of the obtained reaction mixture was adjusted to 5.5 with 25% aqueous ammonia to obtain a polymer latex having a solid content of 55%. The resulting polymer latex contains a glass of the polymerThe glass transition temperature was-25 ℃. Further, the SP value of the polymer contained in the polymer latex was 9.6 (cal/cm)³)^1/2。

< preparation of composition for foam sheet >

The polymer latex (i.e., 100 parts of the polymer contained in the polymer latex) was added in an amount of 100 parts in terms of solid content to a mixing vessel, a carbodiimide-based crosslinking agent (crosslinking agent, "Carbodilite E-02" manufactured by rika textile chemical corporation) was added in an amount of 2.2 parts in terms of solid content to the mixing vessel, and an aqueous titanium oxide dispersion (pigment, "DISPERSE WHITE HG-701" manufactured by DIC corporation) was added in an amount of 4.2 parts in terms of solid content to the mixing vessel, and the mixture was stirred by a dispersing machine. Subsequently, while continuing the stirring, 1.6 parts in terms of solid content of an acrylic copolymer (thickener, manufactured by Toyo Synthesis Co., Ltd., "ARON (registered trademark) B-300K") and 3.6 parts in terms of solid content of ammonium stearate (foam stabilizer, manufactured by San Nopco Co., Ltd., "NOPCO (registered trademark) DC-100-A") were added in this order, and the mixture was filtered through a 150-mesh sieve. Finally, ammonia was added to adjust the viscosity to 4500MPa · s, thereby obtaining a composition for a foam sheet.

< preparation of laminated sheet >

The composition for a foam sheet obtained as described above was stirred by a foamer to foam so that the expansion ratio became 1.6 times, and the stirring was continued for 5 minutes while the stirring speed was further reduced.

The composition for a foamed sheet (foam) after completion of foaming was coated on a sheet-like substrate made of polyethylene terephthalate and having a thickness of 50 μm using a 0.3mm coater. The sheet was placed in a drying oven and held at 80 ℃ for 1.33 minutes, at 120 ℃ for 1.33 minutes, and at 140 ℃ for 1.33 minutes, and drying and crosslinking were carried out to obtain a laminate sheet having a foamed sheet on a base material. The thickness of the dried foam sheet was 0.133 mm. Various evaluations were performed using the obtained laminate sheet. The results are shown in Table 1.

(example 2)

A polymer, a composition for a foam sheet, and a laminate sheet were produced in the same manner as in example 1 except that 7.3 parts by solid content of an epoxy-based crosslinking agent (manufactured by Japan Coating Resins, "Ricbond (registered trademark) EX-8") was used instead of 2.2 parts by solid content of a carbodiimide-based crosslinking agent, and 3.6 parts by solid content of semi-cured tallow fatty acid potassium (manufactured by kao chemical, "song") was used instead of 3.6 parts by solid content of ammonium stearate in preparing the composition for a foam sheet, and various evaluations were performed. The results are shown in Table 1.

(example 3)

A polymer, a composition for a foam sheet, and a laminate sheet were produced in the same manner as in example 1 except that 0.9 parts of lauryl dimethylamino acetic acid betaine (manufactured by first industrial pharmaceutical company, "Amologen (registered trademark) SH") in terms of solid content was added together with ammonium stearate at the time of producing the composition for a foam sheet, and various evaluations were performed. The results are shown in Table 1.

Comparative example 1

In the preparation of the composition for a foam sheet, a polymer, a composition for a foam sheet, and a laminated sheet were prepared in the same manner as in example 1 except that 2.2 parts in solid content of an alkylbetaine amphoteric/fatty acid alkanolamide mixture (product name "DICNAL M-20" manufactured by DIC) and 1.9 parts in solid content of a sulfonic acid type anionic surfactant (product name "DICNAL M-40" manufactured by DIC) were used instead of 3.6 parts in solid content of ammonium stearate, and various evaluations were performed. The results are shown in Table 1.

Comparative example 2

A polymer, a composition for a foam sheet, and a laminate sheet were produced in the same manner as in example 1 except that the amount of ammonium stearate used was changed to 1.2 parts in terms of solid content when preparing the composition for a foam sheet, and various evaluations were performed. The results are shown in Table 1.

[ Table 1]

As is clear from table 1, in examples 1 to 3 using the compositions for foam sheets containing the predetermined polymer, the crosslinking agent and the higher fatty acid salt and having the blending amount of the higher fatty acid salt of not less than the predetermined value, the laminate sheets having excellent outgassing property and suppressed resin residue on the metal even after weather resistance were obtained.

On the other hand, in comparative example 1 using the composition for a foam sheet containing no higher fatty acid salt, it was found that the outgassing property of the laminate sheet was lowered, and further, the resin residue on the metal after weather resistance could not be sufficiently suppressed.

It is also found that in comparative example 2 in which the composition for a foam sheet containing a higher fatty acid salt but having a blending amount of less than a predetermined value was used, the outgassing property of the laminate sheet was reduced.

Industrial applicability

According to the present invention, it is possible to provide a self-adsorptive foamed laminate sheet having excellent outgassing properties and capable of suppressing resin residues on a metal after weather resistance, and a composition for a self-adsorptive foamed sheet that can be used for obtaining the self-adsorptive foamed laminate sheet.

Description of the reference numerals

S1: process for producing composition

S2: foaming step

S3: flaking process

S10: method for producing laminated sheet

10: sample fixing plate

11: through hole

20: syringe with a needle

21: needle

22: outer cylinder

23: piston

30: hammer

40: gas pressure feeding mechanism

50: laminated sheet

51: foamed sheet

52: base material

100: evaluation device