JPWO2016147680A1 - Self-adsorbing foam sheet - Google Patents

Abstract

100 parts by weight of (meth) acrylate copolymer resin having an N-methylol group and a glass transition temperature of −10 ° C. or less, 1 to 20 parts by weight of a crosslinking agent, and 0.1 to 20 of a formaldehyde catcher agent A self-adsorption formed by forming a foam obtained by foaming a resin composition for a self-adsorbing foam sheet containing a mass part, and then performing a crosslinking reaction of a (meth) acrylate copolymer resin. And a self-adsorbing foam laminated sheet having an adsorbing layer made of a self-adsorbing foam sheet and a support layer made of a base material, the amount of formaldehyde generated is extremely small, and has an appropriate self-adhesive force, In addition, a self-adsorbing foam sheet and a self-adsorbing foam laminate sheet excellent in smoothness are provided.

Description

  The present invention relates to a self-adsorbing foam sheet and a self-adsorbing foam laminate sheet, a production method thereof, and a resin composition used for obtaining them.

  In recent years, a sheet-like member made of a foam material having many fine pores and having a self-adsorbing property (hereinafter referred to as “self-adsorbing property”) Foamed sheet ") is used. The adhesive mode of the self-adsorbing foam sheet is not adhesive bonding, but adsorption to the adherend using fine pores, so there is no adhesive residue and it is easy to reattach, including wallpaper and other interior decoration materials It is suitably used for various applications such as decorative materials for construction, and adhering materials for advertisement such as posters and stickers. For use in these applications, a substrate such as a resin film is usually laminated on the self-adsorbing foam sheet, and decoration such as printing is applied to the substrate. Hereinafter, a laminated sheet having an adsorption layer made of a self-adsorbing foam sheet and a support layer made of a substrate is referred to as a “self-adsorbing foam laminated sheet”.

  Conventionally, a resin has been used as the foam material constituting the self-adsorbing foam sheet, and among them, an acrylate copolymer is preferably used from the viewpoint of excellent mechanical strength and weather resistance. However, acrylic ester copolymers are often used having an N-methylol group for the purpose of improving the strength particularly when wet, and a melamine-based crosslinking agent is used in combination for the purpose of further increasing the strength. There were many cases. When an acrylic ester copolymer having an N-methylol group and a melamine crosslinking agent are used in combination, a large amount of formaldehyde is generated during the crosslinking reaction and remains in the self-adsorbing foam sheet. Formaldehyde was generated during the use of the adsorptive foam laminate sheet. Formaldehyde is known as a causative agent of so-called sick house syndrome, and environmental standards are established, and there is a strong demand to reduce the amount of its generation, so such self-adsorbing foam sheets or self-adsorbing foam laminated sheets are used as wallpaper, etc. There was a problem to use.

  As a technique for reducing the amount of formaldehyde generated from a self-adsorbing foam sheet, for example, Patent Document 1 discloses a (meth) acrylic acid ester copolymer resin having no N-methylol group in the molecule and an oxazoline crosslinking agent. It is disclosed that a self-adsorbing foam sheet that generates no or almost no formaldehyde is produced by using a resin composition that contains bismuth.

JP 2006-176893 A

  However, in patent document 1, it replaces with the (meth) acrylic acid ester copolymer resin which has N-methylol group used conventionally, and uses the (meth) acrylic acid ester copolymer resin which has a carboxyl group. In order to obtain an appropriate self-adhesive force, it is necessary to increase the gel fraction of the (meth) acrylic ester copolymer resin, and as a result, the smoothness of the self-adsorbing foam sheet may be impaired, It was difficult to achieve both self-adhesion and sheet smoothness.

  Accordingly, the present invention provides a self-adsorbing foam sheet and a self-adsorbing foam laminate sheet having a very small amount of formaldehyde generated, having an appropriate self-adhesive force, and excellent in smoothness, a production method thereof, and these. It is an object to provide a resin composition used for the purpose.

  As a result of intensive studies in view of the above problems, the present inventors have satisfied the above required characteristics by combining a predetermined (meth) acrylic acid ester copolymer resin, a crosslinking agent, and a formaldehyde catcher agent. Found to get.

  That is, in the first aspect of the present invention, 100 parts by mass of a (meth) acrylic ester copolymer resin having an N-methylol group and a glass transition temperature of −10 ° C. or less, and 1 to 20 parts by mass of a crosslinking agent. Part and the formaldehyde catcher agent 0.1-20 mass parts is a resin composition for self-adsorbing foam sheets.

  In this specification, “(meth) acryl” means “acryl and / or methacryl”.

  According to a second aspect of the present invention, a foam obtained by foaming the resin composition for a self-adsorbing foam sheet according to the first aspect of the present invention is molded into a sheet shape, and then a (meth) acrylic acid ester copolymer is used. It is a self-adsorbing foam sheet obtained by performing a crosslinking reaction of a coalesced resin.

  According to a third aspect of the present invention, there is provided a self-adsorbing foam laminated sheet having an adsorbing layer comprising the self-adsorbing foam sheet according to the second aspect of the present invention and a support layer comprising a substrate.

  The 4th aspect of this invention has 100 mass parts of (meth) acrylic acid ester copolymer resin which has N-methylol group and a glass transition temperature is -10 degrees C or less, 1-20 mass parts of crosslinking agents, A step of producing a resin composition for a self-adsorbing foam sheet, comprising 0.1 to 20 parts by mass of a formaldehyde catcher agent, and foaming the resin composition for a self-adsorbing foam sheet, for a self-adsorbing foam sheet A method for producing a self-adsorbing foam sheet, comprising: a step of obtaining a foam of a resin composition; and a step of crosslinking a (meth) acrylate copolymer resin after forming the foam into a sheet shape It is.

  According to a fifth aspect of the present invention, there is provided a method for producing a self-adsorbing foam laminated sheet having an adsorbing layer comprising a self-adsorbing foam sheet and a support layer comprising a substrate, and having an N-methylol group. And 100 parts by weight of a (meth) acrylic acid ester copolymer resin having a glass transition temperature of −10 ° C. or lower, 1 to 20 parts by weight of a crosslinking agent, and 0.1 to 20 parts by weight of a formaldehyde catcher agent. A step of preparing a resin composition for a self-adsorbing foam sheet, a step of foaming the resin composition for a self-adsorbing foam sheet to obtain a foam of the resin composition for a self-adsorbing foam sheet, And a step of laminating an adsorption layer on a support layer by performing a crosslinking reaction of a (meth) acrylic ester copolymer resin after forming the foam into a sheet, and a self-adsorbing foam laminated sheet How to make It is.

  In the first, fourth, and fifth aspects of the present invention, the crosslinking agent is preferably a melamine-based crosslinking agent or a carbodiimide-based crosslinking agent.

  In the first, fourth, and fifth aspects of the present invention, the gel fraction of the (meth) acrylic ester copolymer resin is preferably 70% or less.

  In the first aspect of the present invention, the formaldehyde catcher agent is preferably an organic amide compound.

  In the third and fifth aspects of the present invention, the substrate is preferably a resin film.

  According to the present invention, the amount of formaldehyde generated is extremely small, has a suitable self-adhesive force, and is excellent in smoothness. Self-adsorbing foam sheet and self-adsorbing foam laminate sheet, production methods thereof, and The resin composition used for obtaining can be provided.

It is a flowchart explaining one Embodiment of the manufacturing method of the self-adsorption foam sheet which concerns on this invention.

  Embodiments of the present invention will be described below. In addition, the form shown below is an illustration of this invention and this invention is not limited to the form shown below. In the present invention, even when referred to as “film”, “sheet” is included, and even when referred to as “sheet”, “film” is included.

1. Resin composition for self-adsorbing foam sheet The resin composition for self-adsorbing foam sheet of the present invention has a N-methylol group and a (meth) acrylic acid ester copolymer having a glass transition temperature of -10 ° C or lower. 100 mass parts of resin, 1-20 mass parts of crosslinking agents, and 0.1-20 mass parts of formaldehyde catcher agents are included.

<(Meth) acrylic ester copolymer resin>
Hereinafter, the (meth) acrylic acid ester copolymer resin used in the present invention will be described. The (meth) acrylic acid ester copolymer resin has an N-methylol group, and its glass transition temperature is −10 ° C. or lower.

  The glass transition temperature of the (meth) acrylic acid ester copolymer resin is −10 ° C. or lower, and preferably −13 ° C. or lower. By making the glass transition temperature of the (meth) acrylic acid ester copolymer resin not more than the above upper limit value, it becomes easy to make the gel fraction of the (meth) acrylic acid ester copolymer resin described later below the predetermined upper limit value, As a result, it becomes easy to produce a self-adsorbing foam sheet and a self-adsorbing foam laminate sheet having an appropriate self-adhesive force and excellent in smoothness.

(Meth) acrylic acid ester copolymer resin is 50% by mass or more of monomer units from (meth) acrylic acid ester monomers and 50% by mass of monomer units from monomers copolymerizable therewith. It is preferably composed of 70% by mass or more of monomer units from (meth) acrylic acid ester monomers and 30% by mass or less of monomer units from monomers copolymerizable therewith. More preferably, it is composed of 80% by mass or more of a monomer unit from a (meth) acrylic acid ester monomer and 20% by mass or less of a monomer unit from a monomer copolymerizable therewith. It is more preferable that the monomer unit consists of 85% by mass or more of the acrylate monomer and 15% by mass or less of the monomer unit from the monomer copolymerizable therewith. By setting the content of the monomer unit from the (meth) acrylic acid ester monomer within the above range, it is possible to impart appropriate tackiness.
In the present invention, the N-methylol group of the (meth) acrylic acid ester copolymer resin is included in the monomer unit copolymerizable with the (meth) acrylic acid ester monomer. It may be contained in the ester monomer unit.

  The (meth) acrylic acid ester monomer that can be used in the present invention is not particularly limited. From the viewpoint of easily making the glass transition temperature of the (meth) acrylic acid ester copolymer resin not more than −10 ° C., the glass transition temperature. It is preferable to contain the unit of the (meth) acrylic acid ester monomer which forms the homopolymer which becomes -20 degrees C or less.

The (meth) acrylic acid ester monomer forming the homopolymer having a glass transition temperature of −20 ° C. or lower is not particularly limited. For example, ethyl acrylate (the glass transition temperature of the homopolymer is −24 ° C. ), N-propyl acrylate (-37 ° C), n-butyl acrylate (-54 ° C), sec-butyl acrylate (-22 ° C), n-heptyl acrylate (-60 ° C), N-hexyl acrylate (-61 ° C), n-octyl acrylate (-65 ° C), 2-ethylhexyl acrylate (-50 ° C), n-octyl methacrylate (-25 ° C), methacrylic acid (Meth) acrylic acid alkyl ester that forms a homopolymer having a glass transition temperature of -20 ° C or lower, such as n-decyl (-49 ° C); 2-methoxyethyl acrylate (-50 ° C) , 3-methoxypropyl acrylate (-75 ° C.), 3-methoxybutyl acrylate (-56 ° C.), ethoxymethyl acrylate (-50 ° C.), and the like. And (meth) acrylic acid alkoxyalkyl ester forming a homopolymer. Among them, (meth) acrylic acid alkyl ester that forms a homopolymer having a glass transition temperature of −20 ° C. or lower, and (meth) acrylic acid alkoxyalkyl ester that forms a homopolymer that has a glass transition temperature of −20 ° C. or lower. (Meth) acrylic acid alkyl ester forming a homopolymer having a glass transition temperature of −20 ° C. or lower is more preferable.
If the glass transition temperature of the (meth) acrylic acid ester copolymer resin can be adjusted to −10 ° C. or lower, methyl acrylate (the glass transition temperature of the homopolymer is 10 ° C.), methyl methacrylate (same as above) 105 ° C.), ethyl methacrylate (63 ° C.), n-propyl methacrylate (25 ° C.), n-butyl methacrylate (20 ° C.), and the like may be used.

  These (meth) acrylic acid ester monomers may be used individually by 1 type, and may use 2 or more types together.

  Monomers copolymerizable with (meth) acrylic acid ester monomers (hereinafter referred to as “monomers for copolymerization”) include N-methylol groups such as N-methylolacrylamide and N-methylolmethacrylamide. It is necessary to use a monomer having By using a monomer having an N-methylol group, it becomes easy to set the gel fraction described below to a predetermined upper limit value or less, and as a result, it has an appropriate self-adhesive force and has excellent smoothness. It becomes easy to produce a foam sheet and a self-adsorbing foam laminate sheet. From this point of view, the proportion of the monomer having an N-methylol group used is a monomer introduced from a monomer having an N-methylol group, with the (meth) acrylate copolymer resin being 100% by mass. The unit is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.5% by mass or more and 5% by mass or less.

  In addition to the monomer having an N-methylol group, another monomer may be used in combination as the copolymerization monomer. The monomer used in addition to the monomer having an N-methylol group is not particularly limited as long as the glass transition temperature of the (meth) acrylic acid ester copolymer resin can be set to −10 ° C. or lower. Specific examples include α, β-ethylenically unsaturated polyvalent carboxylic acid complete ester, alkenyl aromatic monomer, vinyl cyanide monomer, carboxylic acid unsaturated alcohol ester, olefin monomer, and other functional groups. And the like. These monomers may be used individually by 1 type, and may use 2 or more types together.

  Specific examples of the α, β-ethylenically unsaturated polyvalent carboxylic acid complete ester include dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, dimethyl itaconate and the like.

  Specific examples of the alkenyl aromatic monomer include styrene, α-methylstyrene, methyl α-methylstyrene, vinyltoluene and the like.

  Specific examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile and the like.

  Specific examples of the carboxylic acid unsaturated alcohol ester monomer include vinyl acetate.

  Specific examples of the olefin monomer include ethylene, propylene, butene, pentene and the like.

As the monomer for copolymerization, a monomer having a functional group may be used for the purpose of efficiently performing cross-linking between the inside of the copolymer or between the copolymers.
Examples of the functional group include an organic acid group, a hydroxyl group, an amino group, an amide group, a mercapto group, and an epoxy group.

  Although the monomer which has an organic acid group is not specifically limited, As the representative thing, the monomer which has organic acid groups, such as a carboxyl group, an acid anhydride group, and a sulfonic acid group, can be mentioned. In addition to these, monomers containing sulfenic acid groups, sulfinic acid groups, phosphoric acid groups, and the like can also be used.

  Specific examples of the monomer having a carboxyl group include, for example, α, β-ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and α, such as itaconic acid, maleic acid, and fumaric acid. In addition to β-ethylenically unsaturated polyvalent carboxylic acid, α, β-ethylenically unsaturated polyvalent carboxylic acid partial esters such as monomethyl itaconate, monobutyl maleate and monopropyl fumarate can be used. Moreover, what has group which can be induced | guided | derived to a carboxyl group by hydrolysis etc., such as maleic anhydride and itaconic anhydride, can be used similarly.

  Specific examples of the monomer having a sulfonic acid group include allyl sulfonic acid, methallyl sulfonic acid, vinyl sulfonic acid, styrene sulfonic acid, α, β-unsaturated sulfonic acid such as acrylamide-2-methylpropane sulfonic acid, And salts thereof.

  When using a monomer having an organic acid group, the monomer unit derived therefrom is 100% by mass of (meth) acrylic acid ester copolymer resin, preferably 0.1% by mass or more and 20% by mass or less, More preferably, it is used for the polymerization in such an amount that it is 0.5 to 15% by mass. When the amount of the monomer having an organic acid group is within the above range, it becomes easy to keep the viscosity of the polymerization system in an appropriate range at the time of polymerization, and the crosslinking of the copolymer proceeds excessively. Thus, it is easy to prevent the self-adsorption property of the self-adsorbing foam sheet and the self-adsorbing foam laminate sheet from being impaired.

  The monomer unit having an organic acid group can be easily and preferably introduced into the (meth) acrylic acid ester copolymer resin by polymerization of a monomer having an organic acid group. After the acrylic ester copolymer resin is formed, an organic acid group may be introduced by a known polymer reaction.

  Examples of the monomer having a hydroxyl group include (meth) acrylic acid hydroxyalkyl esters such as (meth) acrylic acid 2-hydroxyethyl and (meth) acrylic acid 3-hydroxypropyl.

  Examples of the monomer having an amino group include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and aminostyrene.

  Examples of the monomer having an amide group include α, β-ethylenically unsaturated carboxylic acid amide monomers such as acrylamide, methacrylamide, and N, N-dimethylacrylamide.

  Examples of the monomer having an epoxy group include glycidyl (meth) acrylate and allyl glycidyl ether.

  When using a monomer having a functional group other than these organic acid groups, the monomer unit derived therefrom is 10% by mass or less based on 100% by mass of the (meth) acrylic acid ester copolymer resin. It is preferable to use it for polymerization in such an amount. When the amount of the functional group other than the organic acid group used is 10% by mass or less, it becomes easy to keep the viscosity of the polymerization system at the time of polymerization within an appropriate range, and the crosslinking of the copolymer proceeds excessively. Thus, it is easy to prevent the self-adsorption property of the self-adsorbing foam sheet and the self-adsorbing foam laminate sheet from being impaired.

  Moreover, you may use together the polyfunctional monomer which has two or more polymerizable unsaturated bonds as a monomer for copolymerization. The polyfunctional monomer preferably has the unsaturated bond at the terminal. By using such a polyfunctional monomer, intramolecular and / or intermolecular crosslinking can be introduced into the (meth) acrylic acid ester copolymer resin, and the cohesive force can be increased.

  Examples of the polyfunctional monomer include 1,6-hexanediol di (meth) acrylate, 1,2-ethylene glycol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, polyethylene glycol di ( (Meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ditrimethylolpropane tri Multifunctional (meth) acrylates such as (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 2,4-bis (trichloromethe) Other substituted triazines, such as Le) -6-p-methoxystyrene-5-triazine, etc. monoethylenically unsaturated aromatic ketones such as 4-acryloxy benzophenone can be used. Polyfunctional (meth) acrylates are preferred, and pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate are more preferred. A polyfunctional monomer may be used individually by 1 type, and may use 2 or more types together.

The (meth) acrylic acid ester copolymer resin can be obtained by copolymerizing a (meth) acrylic acid ester monomer and a copolymerization monomer. The polymerization method for obtaining the (meth) acrylic acid ester copolymer resin is not particularly limited, and may be any of solution polymerization, emulsion polymerization, suspension polymerization, bulk polymerization and the like, and may be other methods. There are no particular restrictions on the types and amounts of polymerization initiators, emulsifiers, and dispersants used for polymerization. In the polymerization, there is no particular limitation on the method of adding a monomer, a polymerization initiator, an emulsifier, a dispersant and the like. Moreover, there is no restriction | limiting in polymerization temperature, a pressure, stirring conditions, etc.
The property of the (meth) acrylic acid ester copolymer resin may be a solid or a dispersion, but if a product obtained as an emulsion or a dispersion by emulsion polymerization or dispersion polymerization is used as it is, crosslinking occurs. In mixing with an agent or a conductive compound, the operation is easy, and it is convenient for foaming the obtained emulsion or dispersion.

The gel fraction of the (meth) acrylic acid ester copolymer resin is preferably 70% or less, and more preferably 65% or less. When the gel fraction is within the above range, it becomes easy to produce a self-adsorbing foam sheet and a self-adsorbing foam laminate sheet having an appropriate self-adhesive force and excellent smoothness.
In the present invention, the gel fraction means that a 500 mg sample of an acrylate copolymer resin is immersed in 100 ml of ethyl acetate at room temperature for 3 days, and then the insoluble matter is filtered through a 200 mesh wire net and air-dried at room temperature for 15 hours. Then, it is dried at 100 ° C. for 2 hours, the dry mass of the insoluble matter is measured, and the value obtained by the following formula.
Gel fraction (% by mass) = ((dry mass of insoluble matter after immersion in ethyl acetate) / (sample mass before immersion in ethyl acetate)) × 100

<Crosslinking agent>
The crosslinking agent used for this invention is not specifically limited, For example, the melamine type crosslinking agent conventionally used for the foaming material can be used. As described above, a large amount of formaldehyde is generated during the reaction between the (meth) acrylic acid ester copolymer resin having an N-methylol group and the melamine-based crosslinking agent. However, in the present invention, by including a formaldehyde catcher agent, which will be described later, formaldehyde can be captured and detoxified, an acrylic ester copolymer resin and a melamine-based cross-linking that are preferable combinations from the viewpoint of increasing strength and the like. A self-adsorbing foamed sheet and a self-adsorbing foamed laminated sheet with a very small amount of formaldehyde can be produced while using the agent in combination.

The melamine-based crosslinking agent used in the present invention is not particularly limited, and conventionally known melamine crosslinking agents can be used. For example, melamine, methylol melamine obtained by condensing melamine and formaldehyde, a compound partially or completely etherified by reacting methylol melamine with a lower alcohol, and a mixture thereof can be used. The melamine-based crosslinking agent may be a monomer, a condensate composed of a dimer or higher polymer, or a mixture thereof.
Examples of the methylol melamine include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine and the like.
As the lower alcohol used for etherification of the methylolmelamine, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like can be used.

  The compound contained in the melamine-based crosslinking agent has, for example, an imino group, a methylol group, or an alkoxymethyl group such as a methoxymethyl group or a butoxymethyl group in one molecule as a functional group. Examples of such compounds include imino group type methylated melamine, methylol group type melamine, methylol group type methylated melamine, and fully alkyl type methylated melamine.

  The melamine-based cross-linking agent is obtained by reacting the functional group it has with the N-methylol group in the (meth) acrylic acid ester copolymer resin, to form an intramolecular or intermolecular (meth) acrylic acid ester copolymer. To form a cross-linked structure. A melamine-based crosslinking agent is preferable because it is excellent in a crosslinking effect at a high temperature of 120 ° C. or more and can form a self-adsorbing foam sheet excellent in strength and self-adsorption.

  When a melamine-based crosslinking agent is used as the crosslinking agent, the amount of the melamine-based crosslinking agent used is 1 part by mass or more and 20 parts by mass or less as a solid content with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer resin. It is preferable that it is 3 mass parts or more and 15 mass parts or less. When the usage-amount of a melamine type crosslinking agent exists in the said range, it has moderate self-adhesion force and can raise the resin strength after bridge | crosslinking.

  Moreover, you may use a carbodiimide type crosslinking agent for the crosslinking agent used for this invention instead of a melamine type crosslinking agent or with a melamine type crosslinking agent. By using a carbodiimide crosslinking agent, the amount of formaldehyde generated during the crosslinking reaction of the (meth) acrylate copolymer resin having an N-methylol group can be reduced. Containing a self-adsorbing foam sheet and a self-adsorbing foam laminate sheet that contain less formaldehyde than when using a melamine-based crosslinking agent (for example, the amount generated is less than the detection limit) can do.

  Although the carbodiimide type crosslinking agent used for this invention is not specifically limited, The compound which has a 2 or more carbodiimide group in 1 molecule is used preferably. A known carbodiimide compound can be used as such a compound.

  The known carbodiimide compound may be synthesized or a commercially available product may be used. Examples of commercially available carbodiimide compounds include “DICNAL HX” manufactured by DIC, “carbodilite” manufactured by Nisshinbo Chemical, and the like. When synthesizing a carbodiimide compound, for example, a polycarbodiimide compound obtained by carbodiimidizing a polyisocyanate by a decarboxylation condensation reaction in the presence of a carbodiimidization catalyst can be used.

  Examples of the raw material polyisocyanate include hexamethylene diisocyanate (HDI), hydrogenated xylylene diisocyanate (H6XDI), xylylene diisocyanate (XDI), 2,2,4-trimethylhexamethylene diisocyanate (TMHDI), and 1,12-diisocyanate decane. (DDI), norbornane diisocyanate (NBDI), 2,4-bis- (8-isocyanate octyl) -1,3-dioctylcyclobutane (OCDI), 4,4'-dicyclohexylmethane diisocyanate (HMDI), tetramethylxylylene diene Isocyanate (TMXDI), isophorone diisocyanate (IPDI), 2,4,6-triisopropylphenyl diisocyanate (TIDI), 4,4′diphenylmethane diisocyanate Nate (MDI), tolylene diisocyanate (TDI), hydrogenated tolylene diisocyanate (HTDI), etc. can be used, and stirring and mixing for any time under an inert gas stream or bubbling within a range of 0 to 200 ° C. In addition, it can be synthesized by adding together with a carbodiimidization catalyst, stirring and mixing.

  Here, as the carbodiimidization catalyst, an organic phosphorus compound is preferable, and phospholene oxides are particularly preferable from the viewpoint of activity. Specifically, 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, 1,3-dimethyl-2-phospholene-1-oxide, Examples include 1-ethyl-2-phospholene-1-oxide, 1-methyl-2-phospholene-1 oxide, and double bond isomers thereof.

  The carbodiimide-based cross-linking agent is obtained by reacting the carbodiimi group contained therein with the N-methylol group in the (meth) acrylic acid ester copolymer resin, so that the (meth) acrylic acid ester copolymer is intermolecular or intermolecular. A crosslinked structure is formed. A carbodiimide-based crosslinking agent is preferable because it is excellent in a crosslinking effect particularly at a low temperature and can form a self-adsorbing foam sheet excellent in strength and self-adsorption.

  When a carbodiimide-based crosslinking agent is used as the crosslinking agent, the amount of the carbodiimide-based crosslinking agent used is 0.5 to 20 parts by mass as a solid content with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer resin. It is preferably 2 parts by mass or less, and more preferably 2 parts by mass or more and 15 parts by mass or less. When the amount of the carbodiimide-based crosslinking agent used is within the above range, it has an appropriate self-adhesive force and can increase the resin strength after crosslinking.

  Instead of the melamine-based crosslinking agent and / or carbodiimide-based crosslinking agent, or together with the melamine-based crosslinking agent and / or carbodiimide-based crosslinking agent, other crosslinking agents (for example, polyethylene glycol diglycidyl ether, glycerin polyglycidyl ether, Epoxy resins such as sorbitol polyglycidyl ether and bisphenol A polyglycidyl ether; Aziridine compounds such as ethyleneimine derivatives such as aldehyde and acrolein; Polyfunctional isocyanates such as tolylene diisocyanate, trimethylolpropane tolylene diisocyanate, and diphenylmethane triisocyanate Crosslinking agents; oxazoline-based crosslinking agents; metal salt-based crosslinking agents; metal chelate-based crosslinking agents; peroxide-based crosslinking agents; Moreover, according to this invention, it is also possible to use the crosslinking agent which causes formaldehyde, such as urea-formaldehyde resin and aldehyde resins, such as a phenol formaldehyde resin, by including the formaldehyde catcher agent mentioned later.

<Formaldehyde catcher agent>
The resin composition for self-adsorbing foam sheets of the present invention contains a formaldehyde catcher agent as an essential component. By containing a formaldehyde catcher agent, formaldehyde derived from the components contained in the resin composition for self-adsorbing foam sheets and formaldehyde generated during the crosslinking reaction of the (meth) acrylate copolymer resin are captured and harmless. Therefore, it is possible to reduce the amount of formaldehyde remaining in the self-adsorbing foam sheet, and to produce a self-adsorbing foam sheet and a self-adsorbing foam laminated sheet that generate very little formaldehyde. .

The formaldehyde catcher agent that can be used in the present invention is not particularly limited as long as it is a compound that physically adsorbs formaldehyde or chemically reacts with formaldehyde, and is an organic compound including an inorganic compound or a polymer. It may be.
Specific examples of formaldehyde catcher agents include hydroxylamine sulfate, hydroxylamine hydrochloride, ammonium acetate, urea, ethylene urea, dicyandiamide, polyamide resins, triazine compounds, hydrazide compounds and other nitrogen-containing compounds; stabilized chlorine dioxide and other halogen oxides And metal salts such as disodium hydrogen phosphate, zinc sulfate, calcium chloride, and magnesium sulfate; Of these, nitrogen-containing compounds are preferable from the viewpoint of availability, and organic amide compounds such as urea, ethyleneurea, polyamide resin, and hydrazide compounds are more preferable from the viewpoint of formaldehyde capturing ability, and adhesion and formaldehyde capturing are preferred. Urea and ethylene urea are more preferable from the viewpoint of compatibility with the properties.
These formaldehyde catcher agents may be used alone or in combination of two or more.

  When two or more types of formaldehyde catcher agents are used in combination, a mixture of urea and ethylene urea can be particularly preferably used from the viewpoints of availability, handleability and formaldehyde capture.

  The amount of the formaldehyde catcher agent used is preferably 0.1 parts by mass or more and 20 parts by mass or less as a solid content with respect to 100 parts by mass of the (meth) acrylic ester copolymer resin, and 0.5 parts by mass More preferably, it is 15 parts by mass or less. When the amount of formaldehyde catcher used is within the above range, a self-adsorbing foam sheet and a self-adsorbing foam laminate sheet having an extremely small amount of formaldehyde generated, an appropriate self-adhesive force, and excellent smoothness Can be made.

(Other additives)
The resin composition for a self-adsorbing foam sheet of the present invention is provided with a self-adsorbing foam sheet and a self-adsorbing foam sheet, and a process for improving processability in the manufacturing process of the self-adsorbing foam sheet and the self-adsorbing foam sheet. In order to improve the performance, various additives can be contained.
Examples of additives include foam stabilizers, foaming aids, thickeners, fillers, preservatives, fungicides, gelling agents, flame retardants, anti-aging agents, antioxidants, pigments, dyes, tackifiers An agent, a conductive compound, etc. can be mentioned.

  As the foam stabilizer, fatty acid ammonium such as ammonium stearate, sulfonic acid type anionic surfactant such as alkylsulfosuccinate, quaternary alkylammonium chloride, alkylbetaine amphoteric compound, fatty acid alkanolamine and the like can be used.

  As the foaming aid, sodium lauryl sulfate, sodium alkyldiphenyl ether disulfonate, sodium polyoxyethylene alkylphenol ether sulfate and the like can be used.

  As the thickener, inorganic polymer fine particles such as acrylic polymer particles and fine silica, and reactive inorganic compounds such as magnesium oxide can be used.

  As the filler, calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, barium hydroxide, clay, kaolin, glass powder and the like can be used.

  Examples of antiseptics and fungicides include dihydroxydichlorophenylmethane, sodium pentachlorophenate, 2,3,4,6-tetrachloro-4- (methylsulfonyl) pyridine, 2,3,5,6-tetrachloro- 4- (methylsulfonyl) pyridine, bis (tributyltin) oxide, hexahydro-1,3,5-triethyl-s-triazine, silver complex, zinc complex, and the like can be used.

  As gelling agents, ammonium salts such as ammonium acetate, ammonium chloride, and ammonium carbonate, alkylphenol alkylene oxide adducts, polyvinyl methyl ether, polypropylene glycol, polyether poly formal, methyl cellulose, hydroxyethyl cellulose, silicone-based heat sensitive agents, etc. are used. it can.

  Flame retardants include phosphate ester compounds, halogen phosphate ester compounds, ammonium polyphosphate, antimony trioxide, zinc borate, barium metaborate, ammonium hydroxide, magnesium hydroxide, tin compounds, organophosphorus compounds, Red phosphorus compounds, silicone flame retardants and the like can be used.

  As antioxidant, polyphenol type, hydroquinone type, hindered amine type antioxidants, etc. can be used.

  Examples of pigments and dyes include titanium oxide, carbon black, bengara, and quinacridone.

  Examples of tackifiers include gum rosin, tall oil rosin, wood rosin, hydrogenated rosin, disproportionated rosin, polymerized rosin, maleated rosin, rosin / glycerin ester, hydrogenated rosin / glycerin ester and other rosin resins; terpene resins, Terpene resins such as terpene phenol resins and aromatic modified terpene resins; petroleum resins such as aliphatic petroleum resins, alicyclic petroleum resins and aromatic petroleum resins; coumarone indene resins; terpene phenol resins; A compound selected from a series resin; a hydrogenated rosin ester; a disproportionated rosin ester; a xylene resin and the like can be used.

2. Self-adsorbing foam sheet and self-adsorbing foam laminate sheet The self-adsorbing foam sheet of the present invention is obtained by molding a foam obtained by foaming the resin composition for a self-adsorbing foam sheet of the present invention into a sheet shape. ) A crosslinking reaction of an acrylate copolymer resin is performed.
Moreover, the self-adsorbing foam laminated sheet of the present invention has an adsorption layer made of the self-adsorbing foam sheet of the present invention and a support layer made of a substrate.

Specific examples of the base material used for the self-adsorbing foam laminated sheet include, for example, a paper base material, synthetic paper, a plastic sheet, and the like.
Here, examples of the paper base material include high-quality paper, art paper, coated paper, kraft paper, and laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials. Synthetic paper is a paper whose surface is formed by a combination of a thermoplastic resin and an inorganic filler.
On the other hand, as plastic sheets, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polystyrene resins, polyvinyl chloride resins, acrylic resins, polycarbonate resins, polyamide resins, and fluorine resins such as polytetrafluoroethylene And the sheet | seat which consists of a mixture or laminated body of these resin can be used.
Although the thickness of the support layer which consists of a base material is not specifically limited, Usually, they are 10 micrometers-200 micrometers.
If a substrate having releasability is used as a substrate, after forming an adsorption layer composed of a self-adsorbing foam sheet on the substrate as described later, the substrate is peeled off and used as a self-adsorbing foam sheet. be able to.

3. Manufacturing method Hereinafter, the manufacturing method of a self-adsorbing foam sheet and a self-adsorbing foaming laminated sheet is demonstrated.

  FIG. 1 is a flowchart for explaining a method S10 for producing a self-adsorbing foam sheet of the present invention (hereinafter sometimes abbreviated as “the present production method S10”). As shown in FIG. 1, this manufacturing method S10 includes a resin composition preparation step S1, a foaming step S2, and a sheet forming step S3 in this order. Hereinafter, each step will be described.

(Resin composition preparation step S1)
Resin composition preparation step S1 has an N-methylol group and has a glass transition temperature of −10 ° C. or less (meth) acrylic acid ester copolymer resin 100 parts by mass, a crosslinking agent 1 to 20 parts by mass, It is the process of producing the resin composition for self-adsorbing foam sheets containing 0.1-20 mass parts of formaldehyde catcher agents.

  In the resin composition preparation step S1, a (meth) acrylic acid ester copolymer resin having a N-methylol group as an essential component and having a glass transition temperature of −10 ° C. or lower, a crosslinking agent, and a formaldehyde catcher agent, And the resin composition for self-adsorption foaming sheets can be produced by mixing the other component used as needed by arbitrary methods. Each substance used in this step, the use ratio of each substance, and the like are as described above, and a description thereof is omitted here.

  When the (meth) acrylic acid ester copolymer resin is an emulsion or a dispersion, a cross-linking agent, a formaldehyde catcher agent, and other components are added to this under stirring in the state of an aqueous dispersion or an aqueous solution. It can be easily mixed only by adding.

Even when the (meth) acrylic acid ester copolymer resin is in a solid state, the mixing method is not particularly limited, and may be mixed using, for example, a roll, a Henschel mixer, a kneader or the like. Mixing may be batch or continuous.
Examples of the batch mixer include a high viscosity raw material kneader and a stirrer such as a crusher, a kneader, an internal mixer, and a planetary mixer. Examples of the continuous mixer include a Farrell type continuous kneader in which a rotor and a screw are combined, and a screw type kneader having a special structure. Moreover, the single screw extruder and the twin screw extruder currently used for the extrusion process are mentioned. Two or more of these extruders and kneaders may be combined, or a plurality of machines of the same type may be connected and used.

The form of the resin composition for a self-adsorbing foam sheet of the present invention is not particularly limited, but when it is in the form of an emulsion or dispersion, it is convenient to obtain a self-adsorbing foam sheet.
The viscosity of the emulsion or dispersion is preferably 2,000 to 10,000 mPa · s, more preferably 3,500 to 5,500 mPa · s.

(Foaming step S2)
The foaming step S2 is a step of foaming the self-adsorbing foam sheet resin composition to obtain a foam of the self-adsorbing foam sheet resin composition.

  In the foaming step S2, an unsolidified foam can be obtained by foaming the self-adsorbing foam sheet resin composition produced in the resin composition production step S1. When the resin composition for a self-adsorbing foam sheet is in the form of an emulsion or a dispersion, a foamed emulsion or a foamed dispersion is obtained.

As the foaming method, mechanical foaming is usually employed. The expansion ratio may be appropriately adjusted, but is usually 1.2 to 5 times, preferably 1.5 to 4 times. The method of mechanical foaming is not particularly limited, but it can be carried out by mixing a certain amount of air into the emulsion of the resin composition for self-adsorbing foam sheet and stirring it continuously or batchwise with an Oaks mixer, whipper or the like. it can. The foamed emulsion thus obtained becomes creamy.
Instead of the mechanical foaming, for example, a heat-expandable microcapsule containing a suitable synthetic resin such as a vinylidene chloride copolymer as a shell wall and encapsulating a low-boiling hydrocarbon-based compound is used as an acrylic resin emulsion or a butadiene-based synthetic rubber. The foamable resin composition can also be prepared by a method of adding to the emulsion.

(Sheet forming step S3)
Sheeting process S3 is a process of performing the crosslinking reaction of (meth) acrylic acid ester copolymer resin, after shape | molding a foam into a sheet form.

  In the sheet forming step S3, the method for forming the foam into a sheet is not particularly limited. Suitable methods include, for example, a method of coating the foam on a process paper such as a polyester film that has been subjected to a release treatment, and forming the sheet into a sheet.

  As a method of coating the foam on the process paper, generally known coating apparatuses such as a roll coater, reverse roll coater, screen coater, doctor knife coater, comma knife coater can be used. Coating thickness can be obtained.

  After the foam is formed into a sheet as described above, a self-adsorbing property is obtained by solidifying the sheet-like foam on the process paper by performing a crosslinking reaction of the (meth) acrylate copolymer resin. A foam sheet can be formed. At this time, if a peelable paper is used as the process paper, the self-adsorbing foam sheet can be easily separated from the process paper.

  In the case of producing a self-adsorbing foam laminated sheet, by using the above-mentioned base material as the process paper, in the sheet forming step S3, the self-adsorbing foam laminated sheet can be formed on the base material. A self-adsorbing foam laminated sheet having an adsorbing layer made of an adsorbing foam sheet and a support layer made of a substrate can be produced.

  In the sheet forming step S3, when the crosslinking reaction of the (meth) acrylic acid ester copolymer resin is performed, it is preferably heat-dried. The method of heat drying is not particularly limited as long as the foamed emulsion coated on the process paper can be dried and cross-linked. A normal hot air circulation type oven, hot oil circulation hot air chamber, far infrared heater chamber Etc. can be used. The drying temperature is suitably 60 ° C. to 180 ° C., and the drying conditions can be appropriately selected depending on the properties of the emulsion, the coating amount, the coating thickness, and the like. Rather than carrying out the drying at a constant temperature, it is preferable to perform multi-stage drying in which the drying is performed from the inside at a low temperature in the initial stage and the drying is sufficiently performed at a higher temperature in the later stage.

The density, thickness, hardness and the like of the resulting self-adsorbing foam sheet are adjusted by the mixing ratio of bubbles, the composition of the resin composition for the self-adsorbing foam sheet, the solid content concentration, the heat drying and solidification conditions, and the like. The thickness of the self-adsorbing foam sheet is preferably 0.03 to 3 mm, more preferably 0.05 to 1 mm, and particularly preferably 0.05 to 0.5 mm. When the thickness is less than 0.03 mm, when the self-adsorbing foam sheet of the present invention is used as an article holding material or an article surface protecting material, the impact absorbability is inferior, the article holding force and the article surface protecting function are not sufficient, If it is thicker than 3 mm, the strength of the self-adsorbing foam sheet is inferior. The density of the self-adsorbing foam sheet is not particularly limited, but is preferably 0.1 to 1.0 g / cm ³ from the viewpoint of impact absorption.

  The self-adsorbing foam sheet or the self-adsorbing foam laminated sheet obtained in the sheet forming step S3 is usually wound by a winder after a separator film is pasted on the surface having self-adsorption, press cutting, Cut to a size that is easy to use by cutting with a slitter.

4). Applications The self-adsorbing foam laminate sheet of the present invention is subjected to printing on the substrate surface by, for example, offset printing, seal printing, flexographic printing, silk screen printing, gravure printing, laser printer, thermal transfer printer, inkjet printer, etc. Can do.
The self-adsorbing foam laminated sheet having the substrate surface printed thereon can be used as a decorative material for construction, a sticking material for advertisement, a stationery, or a material for toys. For example, sales promotion cards, so-called POP cards (posters, stickers, displays, etc.), underlays (lunch mats, table mats, stationery, etc.), hamburgers, sushi, fried buckwheat menus, catalogs, panels, Plate (alternative to metal plate), bromide, store price list, information board (sales guidance, direction / destination guidance, confectionery / food, etc.), gardening POP (feed label, etc.), road sign (funeral / house exhibition place) Etc.), display boards (forbidden to enter, forest road work, etc.), calendars (with images), simple whiteboards, mouse pads, coasters, label writer substitute prints, adhesive labels, etc.
Moreover, since the self-adsorbing foam sheet and the self-adsorbing foam laminated sheet of the present invention are excellent in peelability, a part thereof does not remain on the protected article side after peeling. Therefore, it can be suitably used as an article surface protecting material or article holding material for various optical parts, precision parts, and the like.

  The self-adsorbing foam sheet and the self-adsorbing foam laminate sheet of the present invention are very few even if formaldehyde is generated, and by appropriately setting the composition of the resin composition for the self-adsorbing foam sheet, The generation amount can be less than the detection limit (for example, less than 0.1 ppm). Therefore, it is suitable for use in places and applications where the generation of formaldehyde is prohibited or undesirable. That is, the self-adsorbing foam sheet and the self-adsorbing foam laminated sheet of the present invention are suitable for use as an interior decoration material for construction, a stationery, or a toy material.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples. The “parts” and “%” used here are based on mass unless otherwise specified.

[Material property]
<Measurement of Glass Transition Temperature (Tg) of Acrylate Ester Copolymer Resin>
The glass transition temperature (Tg) of the acrylate copolymer resin used as a material for the self-adsorbing foam laminate sheet described later was measured by the following method. The acrylic ester copolymer resin was applied onto a 50 μm thick polyethylene terephthalate film with a 250 μm applicator and dried at room temperature for 24 hours to obtain a resin film. Using this film as a sample, according to JIS K 7121, a glass transition temperature was measured using a measurement temperature of −50 ° C. to 160 ° C., a heating rate of 10 ° C./min, and a differential scanning calorimeter (SII Nanotechnology, DSC 6220). (° C.) was measured. The results are shown in Table 1.

<Measurement of gel fraction of acrylic ester copolymer resin>
The gel fraction of the acrylate copolymer resin used in the self-adsorbing foam laminate sheet produced as described later was measured by the following method. The acrylic ester copolymer resin was applied onto a 50 μm thick polyethylene terephthalate film with a 250 μm applicator and dried at room temperature for 24 hours to obtain a resin film. Using this film as a sample, a predetermined amount (X) (about 500 mg) was precisely weighed and immersed in 100 ml of ethyl acetate at room temperature for 3 days, and then the insoluble matter was filtered through a 200-mesh wire net for 15 hours at room temperature. And then dried at 100 ° C. for 2 hours and cooled at room temperature, and then the mass (Y) of the sample was measured. The gel fraction was calculated by substituting X and Y into the following equation. The results are shown in Table 1.
Gel fraction (%) = (Y) / (X) × 100

[Evaluation item]
<Self-wearing ability>
A test piece cut out to a size of 125 mm × 25 mm was prepared after producing a self-adsorbing foam laminated sheet as described later. The adsorbing surface of the test piece was bonded to a glass plate with a smooth surface, pressed from above the test piece with a 2 kgf load roller, and allowed to stand in an environment of 23 ° C. and 50% RH for 1 hour. Thereafter, the end of the test piece was fixed to the upper chuck of an autograph (AG-IS manufactured by Shimadzu Corporation), the glass plate was fixed to the lower chuck, and the 180 ° peel test was performed at 23 ° C. and 50% RH. Was carried out at a speed of 300 mm / min. The test force at this time was defined as self-adhesion force (N / cm). The results are shown in Table 1. If the result by this evaluation is 0.01-1 N / cm, it can be said that it has an appropriate self-adhesive force.

<Formaldehyde emission assessment>
A self-adsorbing foam laminate sheet was prepared as described later, and a test piece cut into a size of 200 mm × 200 mm was prepared after a separator film was attached to the surface of the adsorption layer. The specimen was placed in a 5 L Tedlar bag and sealed. 2L of air was sealed in it, left in a thermostat set at 23 ° C and 50% RH for 6 hours, and then the formaldehyde concentration in the bag was measured with a detector tube (Gastech, No. 91L). did. Table 1 shows the results when the formaldehyde concentration is 0.2 ppm or less, with “◯” and when the concentration exceeds 0.2 ppm, “X”.

<Glossiness (60 ° gloss)>
The glossiness of the surface of the adsorption layer was measured according to JIS Z 8741 using a gloss meter (manufactured by Tokyo Denshoku Co., Ltd., GP-60A). The results are shown in Table 1. If the result of this evaluation is 35 or more, it can be said that the smoothness of the sheet surface is excellent.

[Production of self-adsorbing foam laminate sheet]
Example 1
In a mixing container, 100 parts of N-methylol group-containing acrylate copolymer resin (I) (composition: ethyl acrylate 46.9 / butyl acrylate 45.8 / acrylonitrile 5.9 / N- Copolymer resin of methylol acrylamide 1.4, glass transition temperature: −25.9 ° C., gel fraction: 43.1%), 7.3 parts of melamine-based crosslinking agent in terms of solid content (DIC Corporation, BECKAMINE M3), 0.3 part of a cross-linking accelerator (made by DIC, CATALYST ACX) in terms of solid content and 4.2 parts of titanium oxide aqueous dispersion (made by DIC, DISPERSE WHITE HG-701) in terms of solid content. Added and stirred with disper. Next, while continuing stirring, 1.6 parts of thickener (carboxylic acid-modified acrylic ester polymer, manufactured by Toagosei Co., Ltd., Aron B-300K) in terms of solid content and 4.1 parts in terms of solid content. Foam stabilizer [Alkyl betaine amphoteric compound / fatty acid alkanolamide mixture (DIC Corporation, DICNAL M-20) / sulfonic acid type anionic surfactant (DIC Corporation, DICNAL M-40) 1/1 mixture], solid content 2.8 parts of a formaldehyde catcher agent (Miki Riken Kogyo Co., Ltd., mixture of Riken Resin C-40 urea and 2-imidazolidinone) was added in this order, and the mixture was filtered through 150 mesh. Finally, ammonia was added to adjust the viscosity to 4,500 mPa · s to obtain a foamable resin composition.
The foamable resin composition was stirred with a whisk, foamed so that the foaming ratio was doubled, and the stirring speed was further reduced and stirring was continued for 5 minutes.
The obtained foamed mixture was applied onto a substrate (polyethylene terephthalate film having a thickness of 50 μm) using a 0.3 mm applicator. This was put into a drying furnace and held at 80 ° C. for 1.33 minutes, at 120 ° C. for 1.33 minutes, and at 140 ° C. for 1.33 minutes to allow dry crosslinking to be carried out on the substrate (adsorption layer (self-adsorbing property)). A self-adsorbing foam laminated sheet according to Example 1 was obtained.

(Example 2)
The composition of the N-methylol group-containing acrylic ester copolymer resin (I) used in Example 1 was changed to have a glass transition temperature of −15.3 ° C. and a gel fraction of 41.5%. A group-containing acrylic ester copolymer resin (II) was used instead of the melamine-based crosslinking agent (DIC Corporation, BECKAMINE M3) and the crosslinking accelerator (DIC Corporation, CATALYST ACX) used in Example 1. The same procedure as in Example 1 was conducted, except that 3.6 parts by weight of carbodiimide-based crosslinking agent (DIC Corporation, DICNAL HX) was used and the content of the formaldehyde catcher agent was 0.9 parts by weight. A sheet according to Example 2 was produced.

(Comparative Example 1)
A sheet according to Comparative Example 1 was produced in the same manner as in Example 1 except that the formaldehyde catcher agent was not used.

(Comparative Example 2)
Instead of the N-methylol group-containing acrylic ester copolymer resin (I) used in Example 1, a carboxyl group-containing acrylic ester copolymer resin (I ′) (composition: ethyl acrylate 49.0 / acrylic) Copolymer resin of butyl acrylate 42.1 / acrylonitrile 6.9 / acrylic acid 2.0, glass transition temperature: −20.9 ° C., gel fraction: 89.6%) and no formaldehyde catcher agent A sheet according to Comparative Example 2 was produced in the same manner as Example 1 except that.

(Comparative Example 3)
Instead of the N-methylol group-containing acrylate copolymer resin (I) used in Example 1, the composition of the carboxyl group-containing acrylate copolymer resin (I ′) used in Comparative Example 1 was changed to glass. Example 1 except that the carboxyl group-containing acrylate copolymer resin (II ′) was changed so as to have a transition temperature of 6.2 ° C. and a gel fraction of 65.4%, and no formaldehyde catcher was used. In the same manner, a sheet according to Comparative Example 3 was produced.

  As shown in Table 1, the sheets according to Examples 1 and 2 each had a low formaldehyde emission amount, had an appropriate self-adhesive force, and were excellent in smoothness. On the other hand, the sheet | seat which concerns on the comparative example 1 which did not use a formaldehyde catcher agent had the high amount of formaldehyde emission. Moreover, the sheet | seat which concerns on the comparative example 2 which does not contain N-methylol group, contains a carboxyl group, and uses acrylic ester copolymer resin with a high gel fraction was inferior to smoothness. In addition, the sheet according to Comparative Example 3 using the acrylic ester copolymer resin containing a carboxyl group having a high glass transition temperature does not adhere to the glass plate in the self-adhesion force measurement test, and is smooth. Was also inferior. In addition, although the formaldehyde emission amount of the sheet | seat which concerns on Comparative Examples 2 and 3 satisfy | fills a reference value, it was larger than the sheet | seat which concerns on Example 1 and 2. FIG.

Claims (14)

100 parts by weight of a (meth) acrylic acid ester copolymer resin having an N-methylol group and a glass transition temperature of −10 ° C. or lower;
1 to 20 parts by mass of a crosslinking agent;
0.1-20 parts by mass of formaldehyde catcher agent,
A resin composition for self-adsorbing foam sheets, comprising:   The resin composition for self-adsorbing foam sheets according to claim 1, wherein the crosslinking agent is a melamine-based crosslinking agent or a carbodiimide-based crosslinking agent.   The resin composition for self-adsorbing foam sheets according to claim 1 or 2, wherein the gel fraction of the (meth) acrylic acid ester copolymer resin is 70% or less.   The resin composition for self-adsorbing foam sheets according to any one of claims 1 to 3, wherein the formaldehyde catcher agent is an organic amide compound.   A foam obtained by foaming the resin composition for a self-adsorbing foam sheet according to any one of claims 1 to 4 is formed into a sheet shape, and then a crosslinking reaction of the (meth) acrylate copolymer resin is performed. Self-adsorbing foam sheet. An adsorption layer comprising the self-adsorbing foam sheet according to claim 5, a support layer comprising a substrate,
A self-adsorbing foam laminate sheet.   The self-adsorbing foaming laminated sheet of Claim 6 whose said base material is a resin film. 100 parts by weight of a (meth) acrylic acid ester copolymer resin having an N-methylol group and a glass transition temperature of −10 ° C. or lower;
1 to 20 parts by mass of a crosslinking agent;
0.1-20 parts by mass of formaldehyde catcher agent,
Including a step of producing a resin composition for a self-adsorbing foam sheet,
Foaming the resin composition for a self-adsorbing foam sheet to obtain a foam of the resin composition for a self-adsorbing foam sheet;
A step of performing a crosslinking reaction of the (meth) acrylic ester copolymer resin after forming the foam into a sheet;
A method for producing a self-adsorbing foam sheet, comprising:   The method for producing a self-adsorbing foam sheet according to claim 8, wherein the crosslinking agent is a melamine-based crosslinking agent or a carbodiimide-based crosslinking agent.   The method for producing a self-adsorbing foam sheet according to claim 8 or 9, wherein the gel fraction of the (meth) acrylic acid ester copolymer resin is 70% or less. A method for producing a self-adsorbing foam laminate sheet having an adsorbing layer comprising a self-adsorbing foam sheet and a support layer comprising a substrate,
100 parts by weight of a (meth) acrylic acid ester copolymer resin having an N-methylol group and a glass transition temperature of −10 ° C. or lower;
1 to 20 parts by mass of a crosslinking agent;
0.1-20 parts by mass of formaldehyde catcher agent,
Including a step of producing a resin composition for a self-adsorbing foam sheet,
Foaming the resin composition for a self-adsorbing foam sheet to obtain a foam of the resin composition for a self-adsorbing foam sheet;
On the base material, after forming the foam into a sheet shape, a step of laminating the adsorption layer on the support layer by performing a crosslinking reaction of the (meth) acrylic ester copolymer resin;
The manufacturing method of the self-adsorption foaming laminated sheet containing this.   The manufacturing method of the self-adsorption foaming laminated sheet of Claim 11 whose said crosslinking agent is a melamine type crosslinking agent or a carbodiimide type crosslinking agent.   The manufacturing method of the self-adsorption foaming laminated sheet of Claim 11 or 12 whose gel fraction of the said (meth) acrylic acid ester copolymer resin is 70% or less.   The manufacturing method of the self-adsorption foaming laminated sheet of Claim 13 whose said base material is a resin film.

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