JP2016102205A - Aqueous surface treatment agent and coating sheet as well as coatability improvement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous surface treatment agent that has an excellent coatability and can form a coating layer having a uniform surface appearance.SOLUTION: An aqueous surface treatment agent is prepared by combining at least one kind aqueous film forming component (A) selected from the group consisting of a surfactant (a), a hydrophilic polymer (b) and a silicone compound (c), and a polyvalent metal ion (B). The polyvalent metal ion (B) may be a divalent metal ion. The proportion of the polyvalent metal ions (B) may be about 0.01 to 50 mmol relative to aqueous film-forming component (A) 1 g. The inventive aqueous surface treatment agent may be an anti-fogging surface treatment agent having a non-ionic surfactant as an essential component. Further, the inventive aqueous surface treatment agent may be a mold-releasing surface treatment agent having a silicone compound (c) as an essential component.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous surface treatment agent that can form a coating layer having excellent coatability and a uniform surface appearance, a coating sheet coated with the aqueous surface treatment agent, and application of an aqueous film forming component using polyvalent metal ions It is related with the sex improvement method.

  Hydrophobic synthetic resin sheets such as styrene resin sheets are used in various fields such as packaging containers for foods and packaging materials for electronic and mechanical parts. Various functions such as anti-fogging properties necessary for improving the visibility of contents are required. In particular, the antistatic property is a characteristic that is widely required in various fields, and the hydrophobic synthetic resin sheet is easily charged with static electricity, and environmental dust (environmental dust) adheres to it. Easy to do. For this reason, a method for antistatic treatment of a sheet has been proposed, and among them, a method of kneading or coating a surfactant as an antistatic agent is general. In particular, from the viewpoint of antistatic properties, a coating method is preferable, but it is difficult to uniformly apply an antistatic agent as a surfactant by coating.

  JP-A-2003-48284 (Patent Document 1) discloses an antistatic polymer film comprising a base polymer film and an antistatic coating layer, wherein the antistatic coating layer contains a polythiophene and a surfactant. An antistatic agent formed by applying a coating solution, wherein the weight ratio of surfactant to polythiophene is 0.1 or more, and the aqueous coating solution contains less than 10% by weight polymer binder and less than 10% by weight organic solvent A functional polymer film is disclosed. In this document, a transparent and inexpensive antistatic sheet is prepared by applying a water-based conductive coating agent containing no binder and no harmful organic solvent to a substrate. Further, in this document, anionic surfactants and nonionic surfactants are described as surfactants.

  However, even with this aqueous coating solution, when applied to a thermoplastic resin sheet, the coating solution has insufficient adhesion, or due to the low followability of the coating film to the sheet, Breakage occurs, and the conductivity is suddenly impaired.

  On the other hand, for food applications, antistatic properties are required for hygiene, but due to changes in temperature and humidity, water vapor adheres as fine water droplets to the surface of the container, resulting in cloudiness and reduced transparency. For example, JP 2004-315802 A (Patent Document 2) discloses a polyhydric alcohol fatty acid ester such as a sucrose fatty acid ester, an acrylic acid polymer or a salt thereof, vinylpyrrolidone alone or Coating layer combining non-ether water-soluble polymers such as copolymers, polyoxyethylene-polyoxypropylene block copolymers, and ether-based hydrophilic polymers such as nonionic surfactants having oxyethylene units A coated resin sheet having (anti-fogging layer) is disclosed. This covering resin sheet also improves releasability by forming protrusions on the surface of the covering layer.

  However, since this coated resin sheet has high surface resistivity and low electrical conductivity, fine particles such as dust are likely to adhere to the surface of the anti-fogging layer or the release layer, which is undesirable from the viewpoint of hygiene in applications such as food.

  In JP 2002-86639 A (Patent Document 3), one surface of a styrene resin sheet is coated with an antifogging agent comprising a fatty acid ester such as a sucrose fatty acid ester, an ether multimer, and polyvinyl alcohol. The other surface is composed of an ether-based multimer and a surfactant selected from polyoxyethylene glycerin fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene aliphatic alcohol ethers, and fatty acid amides. A styrenic resin antifogging sheet coated with a release agent is disclosed.

  However, even this anti-fogging sheet has a large surface resistivity, so that static electricity is easily accumulated and charged, and fine particles such as dust are likely to adhere to the surface.

  Japanese Patent Application Laid-Open No. 2010-37387 (Patent Document 4) discloses an anti-fogging surface treatment containing a nonionic surfactant, a water-soluble polymer, and an anionic surfactant on at least one surface of a resin sheet. An antifogging resin sheet in which an antifogging layer containing an agent is formed and a release layer is formed on the other surface is disclosed. It is described that the release layer can be composed of a release agent such as silicone oil and an ether-based hydrophilic polymer (nonionic surfactant) having an oxyethylene unit. In the example of this document, no release layer is formed.

  However, this antifogging sheet has low applicability and it is difficult to form a uniform antifogging layer. In particular, when an anionic surfactant or the like having a large antistatic effect is blended, the applicability is lowered and the coating appearance tends to be lowered.

JP 2003-48284 A (Claims) JP 2004-315802 A (Claims) JP 2002-86639 A (Claims) JP 2010-37387 A (Claims)

  Accordingly, an object of the present invention is to provide an aqueous surface treatment agent and a coating sheet that can form a coating layer having excellent coatability and a uniform surface appearance, and a method for improving the coatability of an aqueous film-forming component.

  Another object of the present invention is to provide an aqueous surface treatment agent having a high antistatic property and capable of forming a coating layer capable of preventing the adhesion of fine particles such as dust, a coating sheet coated with this treatment agent, and a coating property of an aqueous film forming component. It is to provide an improvement method.

  Still another object of the present invention is to provide an aqueous surface treatment agent capable of forming a coating layer having excellent antifogging properties and / or releasability, a coating sheet coated with this treatment agent, and a method for improving the coating properties of aqueous film-forming components. Is to provide.

  Another object of the present invention is to provide an aqueous surface treatment agent capable of maintaining a uniform coating layer even after secondary processing (secondary molding), and a coated sheet coated with this treatment agent.

  As a result of intensive studies in order to achieve the above object, the present inventors have determined that at least one aqueous composition selected from the group consisting of a surfactant (a), a hydrophilic polymer (b) and a silicone compound (c). The present invention was completed by finding that a coating layer having excellent coatability and a uniform surface appearance can be formed by combining the film component (A) and the polyvalent metal ion (B) as an aqueous surface treating agent. did.

  That is, the aqueous surface treating agent (coating composition) of the present invention is at least one aqueous film formed selected from the group consisting of a surfactant (a), a hydrophilic polymer (b) and a silicone compound (c). A component (A) and a polyvalent metal ion (B) are included. The polyvalent metal ion (B) may be a divalent metal ion (particularly magnesium ion). The surfactant (a) may be a nonionic surfactant (a1) and / or an anionic surfactant (a2). The hydrophilic polymer (b) may be at least one selected from the group consisting of a vinylpyrrolidone polymer, a vinyl alcohol polymer, and a polyoxyalkylene polymer. The silicone compound (c) may be a silicone emulsion. The aqueous surface treating agent of the present invention may further contain a monovalent metal ion. The ratio of the polyvalent metal ion (B) may be about 0.01 to 50 mmol with respect to 1 g of the aqueous film-forming component (A). The aqueous surface treating agent of the present invention may be an antifogging surface treating agent containing the nonionic surfactant (a1) as an essential component. The aqueous surface treatment agent of the present invention may be a releasable surface treatment agent containing the silicone compound (c) as an essential component.

The present invention also includes a base sheet containing a thermoplastic resin and a cover sheet in which a cover layer formed of the aqueous surface treatment agent is laminated on one surface of the base layer. The covering layer may have a surface resistivity of 2 × 10 ¹³ Ω or less. The base material layer may be a biaxially stretched styrene resin sheet. In the coated sheet of the present invention, the antifogging layer formed with the antifogging surface treatment agent is laminated on one surface of the base material layer, and the other surface is formed with the releasable surface treatment agent. A release layer may be laminated.

  In the present invention, at least one aqueous film-forming component (A) selected from the group consisting of a surfactant (a), a hydrophilic polymer (b) and a silicone compound (c) contains a polyvalent metal ion (B). ) To improve the coating property of the aqueous film-forming component (A). The aqueous film-forming component (A) may contain an anionic surfactant (a2).

  In the present invention, as the aqueous surface treatment agent, at least one aqueous film-forming component (A) selected from the group consisting of surfactant (a), hydrophilic polymer (b) and silicone compound (c), Since it is combined with the polyvalent metal ion (B), it is possible to form a coating layer having excellent coatability and a uniform surface appearance. In particular, by adjusting the ratio of polyvalent metal ions, an excellent coating appearance can be realized, and a uniform surface can be formed by a simple method regardless of the type of coating method. In addition, a coating layer that has high antistatic properties and can prevent adhesion of fine particles such as dust can be formed. Furthermore, when a specific surfactant or silicone compound is used, a coating layer having excellent antifogging properties and / or releasability can be formed. Therefore, the obtained covering sheet can be manufactured by a roll-to-roll method, and productivity can be improved. Furthermore, when the coating layer contains polyvalent metal ions, even if the coating sheet is subjected to secondary processing (such as container molding or stretch molding by thermoforming), it is possible to suppress a decrease in the uniformity of the coating layer due to stretching or transfer, A uniform surface (surface state or surface shape) can be maintained. Therefore, for example, if it is an antifogging sheet, the fall of the antifogging property by secondary processing can be suppressed.

[Aqueous surface treatment agent]
The aqueous surface treating agent of the present invention contains an aqueous film-forming component (A) and a polyvalent metal ion (B).

(A) Aqueous film-forming component The aqueous film-forming component (A) is at least one selected from the group consisting of a surfactant (a), a hydrophilic polymer (b), and a silicone compound (c).

(A) Surfactant As the surfactant, a conventional surfactant can be used, and a cationic surfactant or an amphoteric surfactant may be used. However, the effect of improving coating properties and antistatic properties is great. Nonionic surfactant (a1) and anionic surfactant (a2) are preferred.

(A1) Nonionic surfactant The nonionic surfactant (a1) can be roughly classified into a polyhydric alcohol fatty acid ester and an adduct obtained by adding ethylene oxide to an active hydrogen atom of a hydrophobic compound. In the present invention, the nonionic surfactant (a1) is used to mean that it does not include the polyoxyethylene-polyoxypropylene copolymer exemplified by the hydrophilic polymer (b) described later.

Examples of the polyhydric alcohol include C _2-12 alkylene glycols such as ethylene glycol, propylene glycol, butanediol, hexanediol, and neopentyl glycol; diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene. (Poly) oxy C _2-4 alkylene glycol such as glycol and polytetramethylene glycol; glycerin, polyglycerin having a polymerization degree of about 2 to 20 (diglycerin, triglycerin, tetraglycerin, polyglycerin, etc.), trimethylolethane, triglyceride Methylolpropane, pentaerythritol, saccharides (sucrose, sorbitol, mannitol, xylitol, maltitol, sorbitan, ori Sugar, etc.) polyhydroxy compounds, such as (polyhydric alcohols), and others. These polyhydric alcohols can be used alone or in combination of two or more.

The fatty acid may be either a monocarboxylic acid or a polyvalent carboxylic acid, and may be either a saturated or unsaturated fatty acid. The fatty acid includes a component containing a fatty acid, for example, a component containing a fatty acid as a main component (for example, containing 50% by weight or more) (for example, fats and oils such as coconut oil). Fatty _{acids, C 6-40} fatty acids, preferably _{C 8-30} fatty acids (e.g., capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, hydroxy stearic acid, arachidic acid, behenic acid, _{C 8,} such as montanic acid _-26 saturated fatty acids, oleic acid, _{C 8-26} unsaturated fatty acids such as erucic acid), more preferably _{C 10-22} saturated fatty acids _{(e.g., C 10-20} saturated fatty acids), in particular _{C 10-18} saturated fatty acids ( It may be a saturated fatty acid such as lauric acid, myristic acid, palmitic acid or stearic acid or a mixture thereof (such as coconut oil fatty acid) or an unsaturated fatty acid such as oleic acid).

  The polyhydric alcohol fatty acid ester is often selected from sucrose fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitol fatty acid ester, and sorbitan fatty acid ester.

Examples of sucrose fatty acid esters include sucrose laurate (such as sucrose mono- to penta-laurate), sucrose palmitate (such as sucrose mono- to pentapalmitate), and sucrose stearate (sucrose). Sucrose C _8-24 such as sugar mono to pentastearate, sucrose behenate (sucrose mono to pentabehenate, etc.), sucrose oleate (sucrose mono to pentaoleate, etc.) Saturated or unsaturated fatty acid esters (mono to hexaesters etc.), especially sucrose C _8-24 saturated or unsaturated fatty acid esters (mono to tetraesters etc.), etc. may be mentioned.

Examples of glycerin fatty acid esters include esters of glycerin and C _8-24 saturated or unsaturated fatty acids, such as glycerin caprylic acid esters (such as glycerin mono to dicaprylic acid esters), glycerin lauric acid esters (such as glycerin mono to dilauric acid esters). ), Glycerin stearic acid ester (such as glycerin mono to distearic acid ester), glycerin behenic acid ester (such as glycerin mono to dibehenic acid ester), glycerin oleic acid ester (such as glycerin mono to dioleic acid ester) and the like.

Examples of the polyglycerin fatty acid ester include esters of polyglycerin having a polymerization degree of about 2 to 16 and a C _8-24 saturated or unsaturated fatty acid, such as decaglycerin caprylic acid ester (such as decaglycerin mono to decaprylic acid ester), hexa Glycerin laurate (such as hexaglycerin mono to hexalaurate), decaglycerin laurate (such as decaglycerol mono to decalaurate), decaglycerol stearate (such as decaglycerol mono to decastearate), deca Examples thereof include glycerin oleate (such as decaglycerin mono to dekaoleate).

Examples of sorbitol fatty acid esters include esters of sorbitol and C _8-24 saturated or unsaturated fatty acids, such as sorbitol caprylate (such as sorbitol mono to pentacaprylate), sorbitol laurate (sorbitol mono to pentalaurate). Ester), sorbitol palmitate (such as sorbitol mono to pentapalmitate), sorbitol stearate (such as sorbitol mono to pentastearate), sorbitol oleate (such as sorbitol mono to pentaoleate), and the like And sorbitan fatty acid esters corresponding to these fatty acid esters.

These fatty acid esters can be used alone or in combination of two or more. Preferred polyhydric alcohol fatty acid esters include sucrose fatty acid esters, polyglycerin fatty acid esters, glycerin fatty acid esters, particularly sucrose fatty acid esters (such as sucrose C _8-24 saturated fatty acid esters such as sucrose laurate). It is done.

In the ethylene oxide adduct of a hydrophobic compound, examples of the hydrophobic compound having an active hydrogen atom include higher alcohols (such as C _8-24 alcohols such as lauryl alcohol), aromatic hydroxy compounds (such as phenols and alkylphenols). Examples thereof include polyhydric alcohol fatty acid esters having a hydroxyl group, and fats and oils having a hydroxyl group (such as castor oil and hydrogenated castor oil).

As an ethylene oxide adduct of a hydrophobic compound, for example, an ethylene oxide adduct of a higher alcohol (polyoxyethylene C _8-26 alkyl ether such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene octadecyl ether ( Preferably polyoxyethylene C _10-20 alkyl ether)), ethylene oxide adducts of aromatic hydroxy compounds [for example, polyoxyethylene aryl ethers such as polyoxyethylene phenyl ether (preferably polyoxyethylene C _6-10 aryl) ether, etc.); polyoxyethylene alkylaryl ethers such as polyoxyethylene nonylphenyl ether (preferably polyoxyethylene C _4-26 alkyl C _{6- 0} and aryl ether), etc.], a polyhydric ethylene oxide adduct of alcohol fatty acid esters [polyoxyethylene glycerin stearic acid ester, polyoxyethylene sorbitan stearic acid ester, a polyoxyethylene chain, such as polyoxyethylene sorbitol stearate C _8-26 fatty acid ester (preferably C _10-20 fatty acid ester having a polyoxyethylene chain) and the like, and an ethylene oxide adduct of fat (polyoxyethylene castor oil, polyoxyethylene hydrogenated castor oil, polyoxyethylene palm) An ethylene oxide adduct of a hydroxyl group-containing oil such as oil). The number average molecular weight of the polyoxyethylene adduct is, for example, 150 or more (for example, 150 to 35,000), preferably 200 to 20,000, and more preferably about 200 to 10,000.

  In the present invention, the molecular weight can be measured by gel permeation chromatography (GPC) in terms of polystyrene.

  In the ethylene oxide adduct of a hydrophobic compound, the average addition mole number of oxyethylene units may be, for example, 2 to 100, preferably 2 to 50, more preferably about 3 to 30, or about 2 to 10. There may be.

  In the polyhydric alcohol fatty acid ester and its ethylene oxide adduct, the fatty acid is not limited to a single fatty acid but may be a plurality of fatty acids (mixed fatty acids).

A nonionic surfactant (a1) may be comprised independently, and may be comprised combining multiple (same kind or different kind) surfactant. The nonionic surfactant (a1) is at least one component selected from sucrose fatty acid ester, polyglycerin fatty acid ester, glycerin fatty acid ester and polyoxyethylene alkyl ether (such as polyoxyethylene C _10-20 alkyl ether). In particular, at least sucrose fatty acid ester (such as sucrose _C10-20 fatty acid ester such as sucrose laurate) is preferable.

  The nonionic surfactant (a1) can improve anti-fogging properties and the like depending on the application, and can be used at room temperature (for example, from the point of being able to suppress transfer and adhesion and set-off to a roll (particularly a metal roll) in sheeting). It is preferably a solid at 20 to 25 ° C. The melting point or softening point of the nonionic surfactant is 50 ° C. or higher (for example, about 50 to 100 ° C.), preferably 60 ° C. or higher (for example, about 60 to 98 ° C.), more preferably 80 ° C. or higher (for example, 80 to 95). (Degree C).

(A2) Anionic surfactant The anionic surfactant (a2) may be a sulfonate, carboxylate, sulfate ester salt, phosphate salt or phosphate ester salt.

  Basic substances constituting the salt include inorganic bases [ammonia, alkali metals (sodium, potassium, etc.), alkaline earth metals (calcium, magnesium, etc.)], organic bases [lower alkylamines (trimethylamine, triethylamine, tributylamine). Etc.), alkanolamines (ethanolamine, diethanolamine, dimethylaminoethanol, etc.)] and the like. The salt is often an ammonium salt, an alkali metal salt (sodium salt, potassium salt, etc.), an alkylamine salt or an alkanolamine salt.

Examples of the sulfonate include alkane sulfonate [C _10-20 alkane sulfonate such as lauryl sulfonate (such as sodium C _10-18 alkane sulfonate)], arene sulfonate (benzene sulfonate, naphthalene, etc.). C _6-10 arene sulfonates such as sulfonates), alkyl arene sulfonates [C _4-20 alkyl C _6-10 such as octyl benzene sulfonate, undecyl naphthalene sulfonate, dodecyl benzene sulfonate, etc. Arene sulfonates (such as sodium dodecylbenzenesulfonate)], alkyl sulfosuccinates [di-C _6-20 alkyl sulfosuccinates such as di- (2-ethylhexyl) sulfosuccinate (di- (2-ethylhexyl) sulfosuccinate) Such as sodium acid) ], Such as α- olefin sulfonate can be exemplified.

Examples of the carboxylate include saturated carboxylates (C ₈ such as octylate, caprate, laurate, myristate, palmitate, stearate, isostearate, arachidate, and behenate. _-26 saturated fatty acid salts, etc.), unsaturated carboxylates (myristoleate, palmitoleate, petrothelate, oleate, linoleate, linolenate, ricinoleate, elaidate, gatrenate And C _8-26 unsaturated fatty acid salts such as arachidonate, erucate, and brassinate).

As the sulfate ester salt, alkyl sulfate ester salt or alkenyl sulfate ester salt (higher alcohol sulfate ester salt) [lauryl sulfate ester salt (such as sodium lauryl sulfate ester), C _10-20 alkyl sulfate ester salt such as octadecyl sulfate ester salt, oleyl C _10-20 alkenyl sulfates, such as sulfuric acid ester salts (such as sodium oleyl sulfate), alkyl ether sulfate ester salt (lauryl ether sulfate, polyoxyethylene · C _10-20 alkyl ether sulfate, etc. And the like.

Examples of phosphates or phosphate esters include mono- or dialkyl phosphates [octyl phosphate esters (such as sodium octyl phosphate), C _8-20 alkyl phosphate esters such as dodecyl phosphate, etc.] Examples thereof include mono- or dialkyl phosphates such as polyoxyethylene / alkyl phosphate esters (polyoxyethylene / alkyl phosphate sodium, etc.) and polyoxyethylene / alkyl aryl phosphates.

These anionic surfactants (a2) can be used alone or in combination of two or more. Of these anionic surfactants (a2), alkane sulfonates, carboxylates, alkyl sulfate esters, in particular C _10-20 alkane sulfonates (such as C _10-18 sodium alkane sulfonate), saturated or Unsaturated _C10-24 carboxylates (such as _C10-20 unsaturated carboxylates such as potassium oleate) are preferred.

  The anionic surfactant (a2) is also solid at room temperature (20 to 25 ° C.) from the viewpoint that it can improve anti-fogging properties and the like, and can suppress transfer and adhesion to the roll and set-off according to the application. Is preferred. The melting point or softening point of the anionic surfactant (a2) is 50 ° C. or higher (eg about 50 to 300 ° C.), preferably 60 ° C. or higher (eg 60 to 280 ° C.), more preferably 80 ° C. or higher (eg 80 to 80 ° C.). About 250 ° C.).

(B) Hydrophilic polymer As the hydrophilic polymer (b), various polymers can be used, and the hydrophilic polymer (b1) does not contain an oxyalkylene unit (oxyethylene unit, etc.) and a polyoxyalkylene polymer. It can be roughly divided into (b2).

  The hydrophilic polymer (b1) not containing an oxyalkylene unit includes a polymer having a carboxyl group such as poly (meth) acrylic acid or a salt thereof, a polymer having a sulfonic acid group such as ethylene sulfonic acid or a salt thereof, Hydroxyl group-containing polymers such as polyethylene glycol mono (meth) acrylate, vinyl alcohol polymers such as polyvinyl alcohol, amide group-containing polymers such as poly (meth) acrylamide, basic nitrogen atom-containing polymers such as polyvinylpyrrolidone, Examples include vinyl ether polymers, cellulose derivatives, water-soluble polyesters, and natural polymer polysaccharides. These hydrophilic polymers (b1) can be used alone or in combination of two or more.

  Of these hydrophilic polymers (b1), vinyl pyrrolidone polymers, vinyl alcohol polymers, cellulose ethers, alginic acid or salts thereof are preferred.

  The vinyl pyrrolidone-based polymer includes vinyl pyrrolidone or a derivative thereof alone or as a copolymer, for example, polyvinyl pyrrolidone, a copolymer of vinyl pyrrolidone and a copolymerizable monomer [for example, the (meth) acrylic monomer And a copolymer with a copolymerizable monomer such as vinyl acetate, vinyl imidazole and vinyl caprolactam (for example, vinyl pyrrolidone-vinyl acetate copolymer). The vinyl pyrrolidone polymers can be used alone or in combination of two or more. The proportion of vinylpyrrolidone or a derivative unit thereof in the vinylpyrrolidone polymer may be, for example, 30 to 100% by weight, preferably 50 to 95% by weight, and more preferably about 60 to 90% by weight. When the ratio of vinylpyrrolidone or a derivative thereof is 30% by weight or more, it is advantageous in terms of antifogging property.

The glass transition temperature (Tg) of the vinylpyrrolidone polymer is, for example, about 55 to 250 ° C., preferably 60 to 240 ° C. (eg 63 to 230 ° C.), and more preferably 65 to 220 ° C. (eg 68 to 200 ° C.). It may be. The molecular weight of the vinylpyrrolidone polymer is not particularly limited, and is, for example, a weight average molecular weight of 1 × 10 ^{4 to} 500 × 10 ⁴ , preferably 5 × 10 ^{4 to} 300 × 10 ⁴ , more preferably 10 × 10 ⁴ to. It may be about 250 × 10 ⁴ .

  Examples of vinyl alcohol polymers include saponified products of fatty acid vinyl ester polymers (single or copolymer) such as polyvinyl alcohol (fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol), partially acetalized polyvinyl alcohol, and ethylene. -Vinyl alcohol copolymer, vinyl alcohol-ethylene sulfonic acid copolymer, vinyl alcohol-maleic acid copolymer, etc. are mentioned. These vinyl alcohol polymers can be used alone or in combination of two or more. Of these, polyvinyl alcohol is preferred.

  The saponification degree of the vinyl alcohol polymer is not particularly limited, but is, for example, 60 to 100 mol%, preferably 70 to 100 mol% (for example, 80 to 99 mol%), more preferably about 85 to 100 mol%. It may be. The melting point or softening point of the vinyl alcohol polymer may be about 130 to 250 ° C, preferably 150 to 240 ° C, and more preferably about 170 to 230 ° C (for example, 180 to 220 ° C). The degree of polymerization (or average degree of polymerization) of the vinyl alcohol polymer may be, for example, 100 or more (for example, 100 to 5000), preferably 200 to 4000, and more preferably about 500 to 3000.

Cellulose ethers include C _1-4 alkyl cellulose such as methyl cellulose, hydroxy C _2-4 alkyl cellulose such as hydroxyethyl cellulose and hydroxypropyl cellulose, hydroxy C _2-4 alkyl-C ₁ such as hydroxyethyl methyl cellulose and hydroxypropyl methyl cellulose. _And carboxy C _1-4 alkyl cellulose such as _-4 alkyl cellulose and carboxymethyl cellulose. These cellulose ethers can be used alone or in combination of two or more.

  Alginic acid is a linear polymer polysaccharide obtained by extraction from brown algae plants such as kombu, wakame and kajime, and is a heteropolymer containing D-mannuronic acid and L-guluronic acid as constituent units. . Examples of the salt of alginic acid include a salt of alginic acid and an inorganic base. Specifically, ammonium salt; alkali metal salt such as potassium salt and sodium salt; alkaline earth metal salt such as calcium salt and magnesium salt; silver Examples thereof include transition metal salts such as salts and copper salts. Of these salts, monovalent metal salts (such as alkali metal salts) are preferable in addition to ammonium salts. These alginic acids or salts thereof can be used alone or in combination of two or more.

Examples of the polyoxyalkylene polymer (b2) include polyoxyethylene (or polyethylene glycol), polyoxyethylene-polyoxypropylene copolymer [for example, polyoxyethylene-polyoxypropylene block copolymer (hereinafter simply referred to as POE-). Examples thereof include polymers having oxy C _2-4 alkylene units (particularly oxyethylene units). These polyoxyalkylene polymers (b2) can be used alone or in combination of two or more. Of these, POE-POP block copolymers are preferred.

  The content of the ethylene oxide chain in the POE-POP block copolymer is 10 to 99% by weight, preferably 15 to 95% by weight, more preferably 20 to 95% by weight, particularly about 30 to 90% by weight. Also good. The block structure of the block copolymer is not particularly limited, and may be a diblock structure or a triblock structure in which oxyethylene blocks are bonded to both ends of an oxypropylene block.

The POE-POP block copolymer is a copolymer composed of an oxyethylene block — (CH ₂ CH ₂ O) _m — and an oxypropylene block — (CH (CH ₃ ) CH ₂ O) _n —, The ethylene oxide chain content (m / (m + n) × 100) in the copolymer is 10 to 99% by weight, preferably 15 to 95% by weight, more preferably 20 to 95% by weight, especially 30 to 90% by weight. % May be sufficient. The block structure of the block copolymer is not particularly limited, and may be a diblock structure of an oxyethylene block and an oxypropylene block, a triblock structure in which oxyethylene blocks are bonded to both ends of the oxypropylene block, or the like. A copolymer having a triblock structure can be represented by the following formula.

_{HO- (CH 2 CH 2 O)} m1 - (CH (CH 3) CH 2 O) n - (CH 2 CH 2 O) m2 -H

  The content [(m1 + m2) / (m1 + m2 + n) × 100] of the ethylene oxide chain in the triblock copolymer is the same as the content (m / (m + n) × 100) of the ethylene oxide chain in the copolymer. You can select from a range.

  The POE-POP block copolymer may be used alone, or two or more copolymers having different ethylene oxide chain content, block structure, molecular weight, and the like may be used in combination.

  The melting point or softening point of the polyoxyalkylene polymer (b2) is usually less than 60 ° C. (for example, 45 to 59 ° C.), preferably 48 to 59 ° C., more preferably about 50 to 58 ° C. The weight average molecular weight of the polyoxyalkylene polymer (b2) is not particularly limited, and is 1,000 to 1,000,000, preferably 3,000 to 500,000, more preferably 5,000 to 400,000 ( In particular, it may be about 10,000 to 300,000).

(C) Silicone Compound The silicone compound (c) may be aqueous and can be used in various forms. Usually, it is used in the form of an emulsion of silicone oil (an emulsion obtained by emulsifying and dispersing silicone oil).

  Examples of the silicone oil include (halo) alkyl polysiloxanes such as dimethylpolysiloxane, diethylpolysiloxane, and trifluoropropylpolysiloxane; arylpolysiloxanes such as diphenylpolysiloxane; alkylarylpolysiloxanes such as methylphenylpolysiloxane. Can be mentioned. The silicone oil may be a chain polysiloxane or a cyclic polysiloxane.

Furthermore, the silicone oil is a modified silicone oil such as a hydroxyalkyl group (such as a hydroxy _C2-4 alkyl group such as a hydroxyethyl group), a polyoxyalkylene group, an amino group, an N-alkylamino group, a glycidyl group or an epoxy group. Or a silicone oil having a polymerizable group (such as a vinyl group or a (meth) acryloyl group).

  These silicone oils can be used alone or in combination of two or more. Of these silicone oils, dimethylpolysiloxane having high versatility is usually used.

The viscosity of the silicone compound is not particularly limited. For example, the Ostwald viscosity at room temperature (15 to 25 ° C.) is 50 to 50000 cSt (centistokes) (0.5 × 10 ^{−4 to} 500 × 10 ⁻⁴ m ² / s). , Preferably about 100 to 30000 cSt (1 × 10 ^{−4 to} 300 × 10 ⁻⁴ m ² / s), more preferably about 150 to 25000 cSt (1.5 × 10 ⁻⁴ to 250 × 10 ⁻⁴ m ² / s) It may be.

  The ratio of the aqueous film-forming component (A) (the total ratio when a plurality of components are combined) may be about 50% by weight or more, for example, 80% by weight or more, preferably 90% by weight with respect to the entire aqueous surface treatment agent. % Or more, more preferably 95% by weight or more. If the ratio of the aqueous film-forming component is too small, the coating property may be lowered.

(Anti-fogging surface treatment agent)
These aqueous film-forming components (A) can be appropriately selected depending on the application. When the aqueous surface treatment agent of the present invention is an antifogging surface treatment agent (antifogging composition), the antifogging surface treatment agent is usually the nonionic component of the aqueous film-forming component (A). Surfactant (a1) is included as an essential component. The antifogging surface treatment agent may further contain the anionic surfactant (a2) in addition to the nonionic surfactant (a1). By combining the nonionic surfactant (a1) with the anionic surfactant (a2), adhesion of fine particles such as dust can be effectively prevented in the antifogging layer after coating.

  The weight ratio of the nonionic surfactant (a1) and the anionic surfactant (a2) can be selected from the range of the former / the latter = 99/1 to 30/70, for example, 95/5 to 40/60. (For example, 95/5 to 45/55), preferably 90/10 to 50/50 (for example, 90/10 to 60/40), more preferably 90/10 to 65/35 (particularly 90/10 to 70/30) ) If the proportion of the anionic surfactant is too small, the effect of preventing the adhesion of fine particles in the antifogging layer is lowered, and if it is too much, the antifogging property may be lowered.

  The antifogging surface treatment agent further suppresses the decrease in the antifogging property due to the container molding, and further suppresses the decrease in the antifogging property due to the antifogging layer transfer accompanying the winding of the sheet. May be included. The hydrophilic polymer (b) may be a combination of the hydrophilic polymer (b1) and the polyoxyalkylene polymer (b2). In this case, the weight ratio of the two is the former / the latter = 99 / 1-50. / 50, preferably 95/5 to 60/40, more preferably about 90/10 to 65/35. By combining both, the durability of the antifogging layer can be improved.

  The ratio of the hydrophilic polymer (b) is, for example, 1 to 80 parts by weight, preferably 5 to 60 parts by weight (eg 10 to 50 parts by weight), more preferably 100 parts by weight of the surfactant (a). It is about 15-40 weight part (especially 20-30 weight part). If the ratio of the hydrophilic polymer (b) is too large, the antifogging property may be lowered.

  The antifogging surface treatment agent may further contain the silicone compound (c) in order to improve the releasability. The proportion of the silicone compound (c) is, for example, 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight, based on 100 parts by weight of the total of the surfactant (a) and the hydrophilic polymer (b). Preferably it is about 3-25 weight part (especially 5-20 weight part). If the proportion of the silicone compound is too small, the effect of improving the releasability is reduced, and if it is too large, the antifogging property may be lowered.

(Releasable surface treatment agent)
When the aqueous surface treating agent of the present invention is a releasable surface treating agent (releasing composition), the releasable surface treating agent usually contains the silicone compound (c) as an essential component. The releasable surface treatment agent may further contain a surfactant (a) (particularly an anionic surfactant (a2)) in addition to the silicone compound (c).

  The ratio of the surfactant (a) is, for example, 1 to 50 parts by weight, preferably 3 to 40 parts by weight, and more preferably 5 to 35 parts by weight (particularly 8 to 30 parts by weight) with respect to 100 parts by weight of the silicone compound (c). Part by weight). If the proportion of the surfactant (a) is too small, the coating property and the antistatic property are likely to be lowered, and if it is too much, the releasability may be lowered.

(B) Multivalent metal ion The aqueous surface treating agent of the present invention further contains a polyvalent metal ion (B). In the present invention, by adding the polyvalent metal ion (B) to the aqueous surface treatment agent, the coating property of the aqueous surface treatment agent can be improved, a coating layer having a uniform surface can be formed, and the surface resistance of the coating layer can be formed. The rate can also be reduced and adhesion of fine particles can be suppressed. Furthermore, even if the obtained coated sheet is subjected to secondary processing (such as container molding by thermoforming), it is possible to suppress a decrease in the uniformity of the coating layer. Can be maintained.

  Examples of the polyvalent metal ion (B) include divalent metal ions [for example, alkaline earth metal ions such as magnesium ion, calcium ion, strontium ion and barium ion; Group 7 metal ion such as manganese (II) ion; Group 8 metal ions such as iron (II) ions; Group 9 metal ions such as cobalt (II) ions; Group 10 metal ions such as nickel (II) ions; Group 11 metal ions such as copper (II) ions; Zinc ions , Cadmium ions, mercury (II) ions and other group 12 metal ions; tin (II) ions, lead (II) ions and other group 14 metal ions], trivalent metal ions [eg, chromium (III) ions, etc. Group 6 metal ions; group 8 metal ions such as iron (III) ions; group 13 metal ions such as aluminum ions], tetravalent metal ions [eg For example, Group 7 metal ions such as manganese (IV) ions; Group 14 metal ions such as tin (IV) ions, etc.]. These polyvalent metal ions can be used alone or in combination of two or more.

  Among these polyvalent metal ions, a divalent metal ion is preferable from the viewpoint of improving the coating appearance and antistatic properties, and alkaline earth metal ions (particularly magnesium ions) such as magnesium ions and calcium ions are particularly preferable.

  The polyvalent metal ion (B) can usually be used in the form of halide (especially chloride) or inorganic salt (especially inorganic acid salt such as sulfuric acid and nitric acid), for example, metal chloride such as magnesium chloride and calcium chloride. Alternatively, it can be used in the form of an inorganic acid salt such as magnesium sulfate or magnesium nitrate. Among these, from the point that corrosiveness to metals does not become a problem, a form containing no chlorine, for example, an inorganic acid salt such as magnesium sulfate or magnesium nitrate is preferable. In addition, sulfates such as magnesium sulfate are preferable from the viewpoint of improving the wettability of the coating solution and highly improving the coating property. On the other hand, a metal chloride such as magnesium chloride is preferable from the viewpoint that the surface resistivity of the coating layer can be reduced with a small amount.

  The polyvalent metal ion (B) is blended with the surfactant (a) and the hydrophilic polymer (b) because the effect of improving the antistatic property is large in the aqueous film-forming component (A). It is particularly preferable that it is blended with the nonionic surfactant (a1) and the anionic surfactant (a2) from the viewpoint that the effect of improving both coating properties and antistatic properties is great.

  Among these, there are many alkali metal salts in anionic surfactants, and in the conventional technical common sense, adding a polyvalent metal ion decreases the surface activity, so that it was not assumed to be added. On the other hand, in the present invention, it has been found that the application property of the anionic surfactant is improved by the combination with the polyvalent metal ion, and thus the technical significance of the present invention is particularly great.

  The ratio of the polyvalent metal ion (B) can be selected from the range of, for example, about 0.01 to 50 mmol, preferably 0.02 to 30 mmol (for example, 0.04 to 10 mmol) with respect to 1 g of the aqueous film-forming component (A). ), More preferably about 0.03 to 20 mmol (particularly 0.05 to 10 mmol). In particular, regardless of the type of coating method, the ratio of the polyvalent metal ion (B) is an aqueous component because it can easily form a uniform surface and suppress a decrease in the uniformity of the coating layer due to secondary processing. For example, 0.08-50 mmol (for example, 0.1-50 mmol), preferably 0.09-30 mmol (for example, 0.2-30 mmol), more preferably 0.1-20 mmol (1 g) with respect to 1 g of the membrane component (A). For example, about 0.3 to 20 mmol), particularly about 0.11 to 10 mmol (for example, 0.5 to 10 mmol), and for example, about 0.2 to 7 mmol (for example, 0.02 to 5 mmol) from the viewpoint of balance of various characteristics. Preferably, it is about 0.3 to 5 mmol (for example, 0.3 to 3 mmol), more preferably about 0.4 to 2 mmol (particularly 0.5 to 1 mmol).Furthermore, in applications where antistatic properties are required, the ratio of the polyvalent metal ion (B) is, for example, 0.3 to 50 mmol (for example, 0.5 to 50 mmol) with respect to 1 g of the aqueous film-forming component (A), Preferably it is 0.5-30 mmol (for example, 1-30 mmol), More preferably, it is about 1-20 mmol (for example, 3-20 mmol), Especially about 2-5 mmol may be sufficient.

  When the aqueous film-forming component (A) contains the anionic surfactant (a2), the ratio of the polyvalent metal ion (B) is 0.05 to 200 mmol (particularly with respect to 1 g of the anionic surfactant (a2)). 0.3 to 200 mmol), for example, 0.5 to 50 mmol, preferably 1 to 10 mmol, more preferably 1.5 to 5 mmol (particularly 2 to 3 mmol).

  If the ratio of the polyvalent metal ions is too small, the effect of improving the coating property and the antistatic property is reduced, and if it is too large, the mechanical properties of the antifogging layer may be lowered when used for the antifogging layer.

  In applications where corrosion resistance to metals is required, the aqueous surface treatment agent preferably has a low chloride ion concentration from the viewpoint of improving the corrosion resistance, and may be 100 ppm or less based on the entire treatment agent. , 50 ppm or less is preferable, and 10 ppm or less is particularly preferable. Therefore, when using a metal salt containing chlorine (for example, magnesium chloride), the ratio of the polyvalent metal ion (B) is, for example, 0.01 to 0.2 mmol (for example, 0.01 to 0.2 g) with respect to 1 g of the total. 0.1 mmol), preferably 0.02 to 0.18 mmol (for example 0.02 to 0.08 mmol), more preferably about 0.03 to 0.15 mmol (for example 0.03 to 0.05 mmol), especially It may be about 0.04 to 0.12 mmol. In addition, when the ratio of the polyvalent metal ion (B) is within this range, the coating property (surface for forming a uniform surface compared to the aqueous surface treatment agent containing the polyvalent metal ion (B) at a high concentration) Although the appearance is reduced, the coating property can be improved by a method of adjusting the coating method (for example, a method using a roll coater).

(C) Other additives The aqueous surface treatment agent may further contain a monovalent metal ion. Examples of monovalent metal ions include alkali metal ions such as lithium ions, sodium ions, and potassium ions; Group 11 metal ions such as silver ions and copper (I) ions. These monovalent metal ions can be used alone or in combination of two or more. Of these monovalent metal ions, alkali metal ions are preferable, and sodium ions and potassium ions (particularly sodium ions) are particularly preferable from the viewpoint of improving the coating appearance and antistatic properties. Monovalent metal ions can usually be used in the form of halides (especially chlorides) and inorganic salts (especially inorganic acid salts such as sulfuric acid and nitric acid). For example, metal chlorides such as sodium chloride and potassium chloride, sulfuric acid It can be used in the form of inorganic acid salts such as sodium and sodium nitrate.

  The ratio of monovalent metal ions is, for example, 0.1 to 50 mmol, preferably 0.15 to 10 mmol, more preferably 0.2 to 5 mmol (particularly 0.3 to 1 mmol) with respect to 1 g of the aqueous film-forming component (A). ) The molar ratio of the monovalent metal ion to the divalent metal ion (B) is the former / the latter = 90/10/1/99, preferably 80/20 to 10/90, more preferably 70/30 to 20/80. It may be a degree.

  Aqueous surface treatment agents include various conventional additives such as other mold release agents (mineral waxes, plant waxes, synthetic waxes, etc.), stabilizers (antioxidants, UV absorbers, etc.), fillers, Coloring agents, antistatic agents, flame retardants, lubricants, preservatives, viscosity modifiers, thickeners, leveling agents, antifoaming agents, and the like may be included. The ratio of the other additive is not particularly limited, but is about 10% by weight or less (for example, 0.1 to 10% by weight) with respect to the entire processing agent.

  The aqueous surface treatment agent can usually be used in the form of a coating solution (dope) or an impregnation solution, and is usually used as an aqueous composition containing an aqueous solvent. The aqueous solvent preferably contains water, and may be water alone or water and a hydrophilic solvent (especially a water-miscible solvent) [for example, alcohols (methanol, ethanol, isopropanol, etc.), ketones ( Acetone, etc.), ethers (dioxane, tetrahydrofuran, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, butyl cellosolve, etc.), carbitols, etc.] may be used. When water is used, it may be pure water (or ion exchange water) or drinking water.

  The solid content concentration of the aqueous surface treating agent of the present invention can be selected from the range of, for example, about 0.1 to 10% by weight, for example, 0.1 to 7% by weight, preferably 0.3 to 5% by weight, more preferably It is about 0.5 to 3% by weight. The viscosity of the aqueous surface treating agent is, for example, 10 cps (= 0.01 Pa · s) or less, preferably 1.1 to 5 cps (for example, 1.2 to 3 cps) at a temperature of 20 ° C., as measured by a steady flow viscosity measurement method. ), More preferably about 1.3 to 2 cps.

(Method for producing aqueous surface treatment agent)
The aqueous surface treating agent of the present invention can be prepared through a mixing step of mixing the aqueous film-forming component (A) and the polyvalent metal ion (B) using a conventional mixing stirrer or mixing / dispersing machine.

  This mixing step is usually performed in the presence of the aqueous solvent, but when the aqueous film-forming component (A) includes an anionic surfactant (a2) and other components, the mixing step is performed stepwise. Also good.

  Specifically, in the case of an aqueous surface treatment agent containing an anionic surfactant (a2) and other components, a predilution step of diluting the anionic surfactant (a2) with an aqueous solvent in advance, predilution in the presence of the aqueous solvent It is preferable to prepare by the method including this mixing process which mixes the dilution liquid obtained at the process, and another component (especially nonionic surfactant (a1)).

  In the preliminary dilution step, as the solvent, a solvent constituting the aqueous surface treating agent (particularly water or a mixed solvent of water and a hydrophilic solvent) can be used. The water may be pure water (or ion exchange water) or drinking water. This solvent may be added so that the concentration of the anionic surfactant (a2) is, for example, 1 to 50% by weight, preferably 2 to 40% by weight, and more preferably about 5 to 35% by weight.

  The stirring speed is, for example, about 400 to 1200 rpm, preferably about 500 to 1000 rpm, and more preferably about 600 to 900 rpm. The stirring time is, for example, about 10 minutes to 10 hours, preferably about 20 minutes to 5 hours, more preferably about 30 minutes to 3 hours (particularly about 45 minutes to 2 hours).

  The polyvalent metal ion (B) can be added in the preliminary dilution step or the main mixing step. As the solvent, a solvent constituting the aqueous surface treating agent (in particular, water or a mixed solvent of water and a hydrophilic solvent) can be used. The water may be pure water (or ion exchange water) or drinking water. As the polyvalent metal ion (B), the metal salt may be used as it is, or may be used in the form of an aqueous solution. The concentration of the aqueous solution may be added so that the polyvalent metal ion (B) is about 0.01 to 10% by weight, preferably about 0.05 to 5% by weight.

  In this mixing step, in order to adjust the concentration of the treatment agent, after appropriately adding a solvent, the mixture obtained in the preliminary mixing step and other components such as the nonionic surfactant (a1) are mixed. May be.

  The stirring speed is, for example, about 100 to 2000 rpm, preferably 200 to 1500 rpm, and more preferably about 300 to 1000 rpm. The stirring time is, for example, about 5 minutes to 10 hours, preferably about 10 minutes to 5 hours, and more preferably about 20 minutes to 1 hour.

  In addition, you may mix other components, such as a nonionic surfactant (a1), with the mixture of a premixing process in the state of the liquid composition prepared by mixing in the presence of an aqueous solvent, respectively.

[Coating sheet]
In the covering sheet of the present invention, a covering layer formed of the aqueous surface treating agent is laminated on one surface of a base material layer containing a thermoplastic resin.

(Base material layer)
The base layer is a thermoplastic resin such as a resin sheet having molding processability, particularly a hydrophobic synthetic resin sheet, such as an olefin resin (particularly polypropylene resin), a polyester resin (particularly polyethylene terephthalate resin), or a styrene resin. Can be made of resin. In particular, a resin sheet having high moldability, for example, a styrene resin sheet is preferable.

  Styrenic resins include homopolymers containing aromatic vinyl monomers (such as styrene, vinyltoluene, and α-methylstyrene) as constituents, and copolymerization of aromatic vinyl monomers and copolymerizable monomers. Combinations and mixtures thereof are included. More specifically, examples of the styrene resin include non-rubber reinforced styrene resin [polystyrene (GPPS) for general use, styrene- (meth) acrylic acid copolymer, styrene-methyl methacrylate copolymer (MS resin). ), Acrylonitrile-styrene copolymer (AS resin), acrylonitrile-styrene-methyl methacrylate copolymer, etc.], rubber-containing styrene resin [rubber reinforced polystyrene (high impact polystyrene: HIPS), styrene-diene block copolymer] Or its hydrogenated product (polystyrene-polybutadiene-polystyrene block copolymer, etc.), acrylonitrile-butadiene-styrene copolymer (ABS resin), rubber component X (acrylic rubber, chlorinated polyethylene, ethylene-propylene rubber (EPDM), Ethylene-vinegar Vinyl copolymer, etc.) and acrylonitrile A and styrene S is like AXS resin obtained by graft polymerization. These styrenic resins can be used alone or in admixture of two or more. The styrene resin sheet is a highly transparent styrene resin sheet (for example, a non-rubber reinforced styrene resin sheet composed of a non-rubber reinforced styrene resin such as GPPS, a styrene resin and a styrene-diene block copolymer). A styrene resin sheet composed of a coalescence or a hydrogenated product thereof, or a rubber-reinforced styrene resin sheet.

  The base layer is made of various additives such as stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), antistatic agents, crystal nucleating agents, hydrocarbon polymers, plasticizers, mineral oils, It may contain a filler, a colorant and the like.

  The substrate layer can be obtained by a conventional method, for example, a conventional film forming method such as a T-die method or an inflation method. The base material layer may be unstretched, but is preferably stretched. The stretched film may be a uniaxially stretched film, but is preferably a biaxially stretched film. Moreover, you may heat-process (heat-setting process) a stretched film as needed. Examples of the stretching method include conventional stretching methods such as roll stretching, roll stretching, belt stretching, tenter stretching, tube stretching, and stretching methods combining these. The draw ratio can be appropriately set according to the desired sheet properties, and may be, for example, 1.2 to 20 times, preferably 1.5 to 15 times, and more preferably about 2 to 10 times.

The surface of the base material layer may be subjected to a conventional surface treatment such as corona discharge treatment or high frequency treatment. In particular, when the coating layer is an antifogging layer, the surface of the base material layer is preferably subjected to corona discharge treatment, and the antifogging layer is formed on the corona discharge treatment surface. Although the surface tension of the base material layer varies depending on the type of sheet and cannot be determined unconditionally, it is 30 to 65 dyn / cm (30 × when measured in accordance with JIS K6768 “wetting test method for polyethylene and polypropylene film”). 10 ^{−5 to} 65 × 10 ⁻⁵ N / cm). In the case of a styrene resin sheet, the surface tension is 40 to 62 dyn / cm (40 × 10 ^{−5 to} 62 × 10 ⁻⁵ N / cm), preferably 42 to 62 dyn / cm (42 × 10 ^{−5 to} 62 × 10 ^{− 5} N / cm), more preferably about 45 to 60 dyn / cm (45 × 10 ^{−5 to} 60 × 10 ⁻⁵ N / cm).

  If the surface tension on the surface of the base material layer is too high, the surface of the base material layer is excessively activated, or the blocking becomes easy. Therefore, it becomes difficult to rewind a sheet wound in a roll shape, or when a plurality of molded containers are stacked and punched out, the containers are brought into close contact with each other, and the work efficiency of separating the containers and storing the contents decreases. easy.

(Coating layer)
The coating layer is formed of the aqueous surface treatment agent, but has a surface resistivity of 2 × 10 ¹³ Ω from the viewpoint of preventing adhesion of fine particles (particularly dust and chips generated in the stamping process of the molded sheet). For example, it may be about 1 × 10 ⁷ to 1 × 10 ¹³ Ω (particularly 1 × 10 ⁸ to 8 × 10 ¹² Ω). In the present invention, the surface resistivity can be measured by a method described in Examples described later in accordance with JIS K6911.

The coating layer may be an antifogging layer formed with the antifogging surface treatment agent, and the surface resistivity of the antifogging layer is, for example, 1 × 10 ⁷ to 1 × 10 ¹³ Ω, preferably 1 × 10. ^It may be about ⁸ to 8 × 10 ¹² Ω, more preferably about 1 × 10 ⁸ to 1 × 10 ¹² Ω.

The coating layer may be a release layer formed of the release surface treatment agent, and the surface resistivity of the release layer is, for example, 1 × 10 ⁷ to 1 × 10 ¹³ Ω, preferably 1 × 10. ^It may be about ⁸ to 1 × 10 ¹² Ω, more preferably about 1 × 10 ^{8 to} 5 × 10 ¹¹ Ω (particularly 1 × 10 ⁸ to 1 × 10 ¹¹ Ω).

  The contact angle of the coating layer coating solution with respect to the uncoated styrene resin sheet may be 50 ° or less, for example, 30 to 50 °, preferably 32 to 48 °, more preferably about 35 to 46 °. Also good. If the contact angle is too high, wettability may decrease, or applicability may decrease. In particular, the contact angle of the antifogging layer coating solution with respect to the uncoated styrene resin sheet may be, for example, 40 to 50 °, preferably 41 to 49 °, and more preferably about 42 to 48 °. The contact angle of the release layer coating solution with respect to the uncoated styrene resin sheet may be, for example, 30 to 45 °, preferably 32 to 43 °, and more preferably about 35 to 40 °.

[Method for producing coated sheet]
The covering sheet of this invention can be manufactured by apply | coating an aqueous surface treating agent to the at least one surface of a base material layer. For application of the aqueous surface treating agent (coating liquid), conventional coating means such as spray, roll coater, bar coater, gravure roll coater, knife coater, dip coater and the like can be used. Of these, roll coaters and bar coaters are widely used. If necessary, the coating solution may be applied multiple times. After the coating liquid is applied to the base material layer, the coating layer is usually dried, and then spread on a roll (for example, a metal roll such as a guide roll) and wound on a winding roll.

The coating amount of the aqueous surface treatment agent (coating amount after drying), for example, be selected from 1 to 200 mg / ^{m 2} about a wide range, usually, 2~150mg / ^{m 2,} preferably from 3 to 100 mg / ^{m 2,} further Preferably, it may be about 5 to 50 mg / m ² .

  Furthermore, in the present invention, the antifogging surface treatment agent is applied to one surface of the base material layer to laminate the antifogging layer, and the release surface treatment agent is applied to the other surface. The release layer may be laminated by this. Since the coating sheet in which the antifogging layer and the release layer are laminated can be wound without contaminating the roll, the antifogging component can be greatly suppressed from being transferred (set back) even in the core sheet. High anti-fogging property can be maintained over a long period of time. Moreover, whitening can be suppressed and the transparency and gloss of the resin sheet are not impaired. Therefore, it can be used for various uses, for example, a cover sheet (or film), a packaging sheet (or film) such as food packaging.

The coating amount (coating amount after drying) of the antifogging surface treatment agent can be selected from a wide range of about ^{2 to} 150 mg / m ² (for example, 3 to 100 mg / m ² ), and is usually 5 to 60 mg / m ^2. (For example, 7-50 mg / m < ² >), Preferably about 10-40 mg / m < ² > may be sufficient.

The coating amount of the release layer (coating amount after drying) can be selected from a wide range of about 1 to 200 mg / m ² (for example, 5 to 100 mg / m ² ), and is usually ^{2 to} 100 mg / m ² , preferably 3-50 mg / m < ² > (for example, 5-30 mg / m < ² >), More preferably, about 5-25 mg / m < ² > may be sufficient.

  The covering sheet may be continuously provided in a post-processing step (such as a container forming step), but is usually often wound into a roll and used in the post-processing step. The coated sheet of the present invention has high secondary processability and is suitable for forming a container or the like. In many cases, a container is formed from a coated sheet by a conventional thermoforming method. Examples of thermoforming methods include blow molding, vacuum forming, pressure forming (heating plate heating type pressure forming method, radiation heating type pressure forming method, etc.), vacuum pressure forming method, plug assist forming. Method and matched mold forming method can be used. When using a stretched resin sheet, a hot plate heating type pressure forming method is usually used in many cases.

  Particularly, an antifogging sheet in which an antifogging layer and a release layer are laminated can maintain high antifogging properties and transparency even when subjected to such thermoforming. Furthermore, since the anti-fogging sheet can prevent adhesion of fine particles, the anti-fogging sheet may be a sheet obtained by a method including punching in the manufacturing process. For example, after a container (tray part) for food or the like is continuously molded in the vertical and / or horizontal direction, a container having each container is obtained by continuously punching the obtained molded sheet. It can be suitably used for a method of separating (cutting). In the punching process, a plurality of sheets may be laminated and used for the punching process. In such a method, chips are easily generated, and thus an antifogging sheet that can suppress the adhesion of chips is useful.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. In addition, the detail of the component used by the Example and the comparative example is as follows, The antifogging sheet | seat obtained by the Example and the comparative example was evaluated by the following items.

[Ingredients used]
Nonionic surfactant 1 (a1-1): sucrose fatty acid ester, “Rikemar A” manufactured by Riken Vitamin Co., Ltd., melting point 90 ° C., solid content concentration 40% by weight
Nonionic surfactant 2 (a1-2): polyglycerin fatty acid ester, “Poem J-0021” manufactured by Riken Vitamin Co., Ltd.
Nonionic surfactant 3 (a1-3): coconut oil fatty acid diethanolamide, “Prophan 128 Extra” manufactured by Sanyo Chemical Industries
Nonionic surfactant 4 (a1-4): Polyethylene oxide-added sorbitan fatty acid ester, “Reodol Super TW-L120” manufactured by Kao Corporation
Anionic surfactant 1 (a2-1): sodium alkanesulfonate, “KTN-8006” manufactured by Sanyo Chemical Industries, Ltd., solid content concentration 35% by weight
Anionic surfactant 2 (a2-2): potassium oleate, “FR-14” manufactured by Kao Corporation, solid content concentration 20% by weight
Hydrophilic polymer 1 (b-1): polyoxyethylene-polyoxypropylene block copolymer, “Epan U108” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., melting point 57 ° C., weight average molecular weight 18000, ethylene oxide content 80%
Hydrophilic polymer 2 (b-2): Polyvinylpyrrolidone, “Socaran K90P” manufactured by BASF, glass transition temperature 180 ° C., weight average molecular weight 90 × 10 ^{4 to} 150 × 10 ⁴
Hydrophilic polymer 3 (b-3): polyvinyl alcohol, “PVA-505” manufactured by Kuraray Co., Ltd.
Release agent (c-1): Silicone emulsion, “SM7025EX” manufactured by Toray Dow Corning Co., Ltd., solid content concentration: 33% by weight
Metal salt 1 (B-1): Magnesium chloride hexahydrate (Mg ²⁺ ), manufactured by Nacalai Tesque Co. Metal salt 2 (B-2): Calcium chloride dihydrate (Ca ²⁺ ), Nacalai Tesque (Co., Ltd.) Metal salt 3 (B-3): Sodium chloride (Na ⁺ ), manufactured by Nacalai Tesque Co. Metal salt 4 (B-4): Magnesium sulfate heptahydrate (Mg ²⁺ ), manufactured by Nacalai Tesque Co., Ltd. .

[Appearance appearance (application spots)]
The covering sheet was placed on the black pressure-sensitive adhesive sheet so that the coated surface was on top, and the appearance of the covering layer of the covering sheet was visually observed and evaluated according to the following criteria.

3: There is no coating spot 2: When the eyes are closed, the coating spot can be recognized by the degree of light contact 1: The coating spot is conspicuous.

[Appearance (white dots)]
The appearance of the coating layer of the coating sheet was visually observed and evaluated according to the following criteria.

3: No white spots 2: Fine white spots can be recognized 1: White spots stand out at a level that cannot be used practically.

[Surface resistivity and antistatic properties]
In accordance with JIS K6911, the coated sheet was cut into 5 cm × 10 cm, and the resistance meter (“Hiresta-up MCP-HT450” manufactured by Mitsubishi Chemical Corporation) was used at a temperature of 23 ° C. and a humidity of 50% RH. The surface resistivity when a voltage was applied was measured. In the table, “over” means a value exceeding 1 × 10 ¹⁴ Ω.

Furthermore, about the coating sheet obtained by the Example, the improvement effect (antistatic property) with respect to the comparative example which does not add a metal salt (metal ion) was evaluated on the following references | standards. In Comparative Example exceeding the 1 × ^{10 14} Ω it was calculated as 1 × ^{10 14} Ω.

◎: surface resistivity as compared with the addition of non-metal salt is decreased by 10 ^three orders or more ○: metallic salts not added as compared to the surface resistivity is reduced 10 ² orders △: Compared with added non metal salt × surface resistivity is reduced 10 ¹ order: surface resistivity as compared with the addition of non-metal salts are the same order.

[Contact angle]
Using an automatic contact angle meter (“model CA-Z” manufactured by Kyowa Interface Science Co., Ltd.), the contact angle of the coating layer coating solution was measured. Specifically, for the contact angles of Examples 18 to 31 and Comparative Examples 10 to 19, about 1.5 μL of each liquid was deposited on the corona discharge treated surface (54 dyn / cm) of the uncoated biaxially stretched polystyrene sheet. Ten contact angles one second after dropping were measured and averaged. On the other hand, about the contact angles of Examples 32-36 and Comparative Examples 20-22, about 1.5 μL of the release layer coating solution was applied to the untreated surface of the uncoated biaxially stretched polystyrene sheet. Ten contact angles one second after dropping were measured and averaged.

[Anti-fogging property (sheet)]
The sheet was placed with the antifogging layer of the antifogging sheet facing the opening of a container containing hot water at 60 ° C., and left in a room temperature environment for 2 minutes. Next, the steam contact portion of the sheet was placed on characters with different font sizes printed on paper, and the degree of fogging of the sheet was visually evaluated according to the following criteria.

○: Characters with a font size of 5 can be read clearly. Δ: Characters with a font size of 18 can be read. ×: Characters cannot be identified.

[Anti-fogging property (secondary processed product)]
At the opening of a container containing hot water at 60 ° C., a secondary processed product of the antifogging sheet (stretching ratio 1.6 times, stretching ratio = sheet thickness / sheet thickness after secondary processing) is applied to the antifogging layer. The sheet was placed toward the opening and left for 2 minutes in a room temperature environment. Next, the steam contact portion of the secondary processed product was placed on characters with different font sizes printed on paper, and the degree of cloudiness of the sheet was visually evaluated according to the following criteria.

○: Characters with a font size of 5 can be read clearly. Δ: Characters with a font size of 18 can be read. ×: Characters cannot be identified.

Examples 1-10 and Comparative Examples 1-4
(Preparation of coating solution containing nonionic surfactant (a1))
Water (ion-exchanged water) is added to each component and mixed with stirring so that the solid content ratio of each component (weight ratio after drying of each component) is the ratio (parts by weight) shown in Table 1, and the solid content concentration A coating solution for forming a 0.6 wt% coating layer was prepared.

(Manufacture of coated sheets)
One surface of a biaxially stretched polystyrene sheet having a sheet thickness of 0.25 mm was subjected to corona discharge treatment at 54 dyn / cm or more, and the coating solution for coating layer was applied to the corona discharge treatment surface at a coating amount of 20 mg / m ² after drying. . The coating layer was formed by applying with a 5 Mayer bar and drying for 2 minutes with a hot air dryer at 80 ° C.

Table 1 shows the results of evaluating the appearance and surface resistivity of the obtained coated sheet. In addition, the unit of composition in all the following tables | ^surfaces is a weight part except a metal salt (Mg <^2+> , Ca <^2+> ), and a metal salt is the mmol number of the metal ion with respect to 1g of solid content.

  As is clear from the results in Table 1, the coated sheet obtained in the examples was formed with an aqueous surface treatment containing a nonionic surfactant as a main component, but the coating appearance and antistatic properties were confirmed. Excellent in properties.

Example 11 and Comparative Example 5
After using the anionic surfactant (a2) instead of the nonionic surfactant (a1) to prepare a coating solution in the same manner as in Example 1 at the ratio shown in Table 2, the same as in Example 1 A coated sheet was produced by the method described above. Table 2 shows the results of evaluating the appearance and surface resistivity of the obtained coated sheet.

  As is apparent from the results in Table 2, the coating sheet obtained in the examples was formed with an aqueous surface treating agent containing an anionic surfactant as a main component, but the coating appearance and antistatic properties were Is excellent.

Examples 12-16 and Comparative Examples 6-8
Using the hydrophilic polymer (b) instead of the nonionic surfactant (a1) and preparing the coating solution in the same manner as in Example 1 at the ratio shown in Table 3, the same as in Example 1 A coated sheet was produced by this method. Table 3 shows the results of evaluating the appearance and surface resistivity of the obtained coated sheet.

  As is apparent from the results in Table 3, the coated sheets obtained in the examples have excellent coating appearance and antistatic properties despite being formed with an aqueous surface treatment agent mainly composed of a hydrophilic polymer. Are better.

Example 17 and Comparative Example 9
(Preparation of coating solution containing release agent (c))
Water (ion-exchanged water) is added to each component and mixed by stirring so that the solid content ratio of each component (weight ratio after drying of each component) is the ratio (parts by weight) shown in Table 4, and the solid content concentration A coating solution for forming a 0.3% by weight coating layer was prepared.

(Manufacture of coated sheets)
One surface of the biaxially stretched polystyrene sheet having a sheet thickness of 0.25 mm was subjected to a coating amount of 18 mg / m ² after drying without applying a corona discharge treatment. The coating layer was formed by applying with a 5 Mayer bar and drying for 2 minutes with a hot air dryer at 80 ° C.

  Table 4 shows the results of evaluating the appearance and surface resistivity of the obtained coated sheet.

  As is clear from the results in Table 4, the coated sheets obtained in the examples are excellent in coating appearance and antistatic properties despite being formed with an aqueous surface treatment agent mainly composed of a release agent. ing.

Examples 18-36 and Comparative Examples 10-22
(Preparation of coating solution combining multiple aqueous film forming components)
Water (ion-exchanged water) is added to each component and mixed with stirring so that the solid content ratio of each component (weight ratio after drying of each component) is the ratio (parts by weight) shown in Tables 5 and 6. A coating solution for forming a coating layer having a partial concentration of 0.6% by weight was prepared. In addition, about Example 27 and Comparative Example 18, it prepared to solid content concentration 0.3 weight%.

(Manufacture of coated sheets)
One surface of a biaxially stretched polystyrene sheet having a sheet thickness of 0.25 mm was subjected to corona discharge treatment at 54 dyn / cm or more, and the coating solution for coating layer was applied to the corona discharge treatment surface at a coating amount of 20 mg / m ² after drying. . The coating layer was formed by applying with a 5 Mayer bar and drying for 2 minutes with a hot air dryer at 80 ° C.

For Examples 32-36 and Comparative Examples 20-22, one surface of the biaxially stretched polystyrene sheet was not subjected to corona discharge treatment, and was applied for a release layer at a coating amount of 18 mg / m ² after drying. The liquid was No. The coating layer was formed by applying with a 5 Mayer bar and drying for 2 minutes with a hot air dryer at 80 ° C.

  Tables 5 and 6 show the results of evaluating the appearance and surface resistivity of the obtained coated sheet.

  As is apparent from the results in Tables 5 and 6, the coated sheets obtained in the examples are excellent in coating appearance and antistatic properties despite the combination of a plurality of aqueous film-forming components. In Examples 35 and 36, although there was no effect of improving the antistatic property, the level was not a problem in practical use. As in Examples 30 and 31, the contact angle was small and the coating property was highly improved. .

Examples 37 to 40 and Comparative Example 23
(Preparation of coating solution)
Water (ion-exchanged water) was added to each component and stirred and mixed so that the solid content ratio of each component (weight ratio after drying of each component) was the ratio (parts by weight) shown in Table 7. A coating solution for forming a 0.64% by weight antifogging layer (antifogging layer coating solution) and a release layer coating solution having a solid concentration of 1.08% by weight were prepared. In addition, the unit of a composition in Table 7 is a weight part except a metal salt (Mg ^<2+> ), and a metal salt is the mmol number of the metal ion with respect to 1g of solid content.

(Manufacture of coated sheets)
One surface of a biaxially stretched polystyrene sheet having a sheet thickness of 0.25 mm is subjected to corona discharge treatment at 54 dyn / cm or more, and a coating solution for an antifogging layer is applied to the corona discharge treatment surface at a coating amount of 20 mg / m ² after drying. The anti-fogging layer was formed by apply | coating with a roll coater and drying for 2 minutes with a 80 degreeC hot air dryer. Further, the other surface of the biaxially stretched polystyrene sheet was not subjected to corona discharge treatment, but was applied with a release layer coating liquid at a coating amount of 18 mg / m ² after drying with a roll coater, and dried with hot air at 80 ° C. A release layer was formed by drying for 2 minutes on a machine. Table 7 shows the results of evaluating the triboelectric charging potential, surface resistivity, antifogging properties (sheet and secondary processed product), coating appearance and metal corrosivity of the obtained coated sheet.

  As is apparent from the results in Table 7, the coated sheets and molded articles obtained in the examples have a negative triboelectric potential and a low surface resistivity. Further, both the antifogging sheet and the secondary processed product thereof are excellent in antifogging properties. Furthermore, the coating appearance is also excellent.

  The aqueous surface treating agent of the present invention is used in various fields where antistatic properties are required, for example, fields such as packaging containers for foods, packaging materials for electronic / mechanical parts, and the like. Among them, the anti-fogging surface treatment agent is used for various applications that require anti-fogging properties, for example, various containers (contents), in particular, containers for storing containers (food, etc.) containing moisture. It is useful for such as.

Claims (16)

  At least one aqueous film-forming component (A) selected from the group consisting of a surfactant (a), a hydrophilic polymer (b) and a silicone compound (c), and a polyvalent metal ion (B) Aqueous surface treatment agent.   The aqueous surface treating agent according to claim 1, wherein the polyvalent metal ion (B) is a divalent metal ion.   The aqueous surface treating agent according to claim 2, wherein the divalent metal ion is magnesium ion.   The aqueous surface treating agent according to any one of claims 1 to 3, wherein the surfactant (a) is a nonionic surfactant (a1) and / or an anionic surfactant (a2).   The aqueous polymer according to any one of claims 1 to 4, wherein the hydrophilic polymer (b) is at least one selected from the group consisting of a vinylpyrrolidone polymer, a vinyl alcohol polymer and a polyoxyalkylene polymer. Surface treatment agent.   The aqueous surface treating agent according to any one of claims 1 to 5, wherein the silicone compound (c) is a silicone emulsion.   Furthermore, the aqueous surface treating agent in any one of Claims 1-6 containing a monovalent metal ion.   The ratio of polyvalent metal ion (B) is 0.01-50 mmol with respect to 1 g of aqueous film-forming component (A), The aqueous surface treating agent in any one of Claims 1-7.   The aqueous surface treatment agent according to any one of claims 1 to 8, which is an antifogging surface treatment agent comprising a nonionic surfactant (a1) as an essential component.   The aqueous surface treating agent according to any one of claims 1 to 8, which is a releasable surface treating agent containing the silicone compound (c) as an essential component.   The base material layer containing a thermoplastic resin, and the coating sheet by which the coating layer formed with the aqueous surface treating agent in any one of Claims 1-10 is laminated | stacked on one surface of this base material layer. The coated sheet according to claim 11, wherein the surface resistivity of the coating layer is 2 × 10 ¹³ Ω or less.   The covering sheet according to claim 11 or 12, wherein the base material layer is a biaxially stretched styrene resin sheet.   The antifogging layer formed with the antifogging surface treatment agent according to claim 9 is laminated on one surface of the base material layer, and formed on the other surface with the releasable surface treatment agent according to claim 10. The covering sheet according to any one of claims 11 to 13, wherein a release layer is laminated.   Adding a polyvalent metal ion (B) to at least one aqueous film-forming component (A) selected from the group consisting of a surfactant (a), a hydrophilic polymer (b) and a silicone compound (c) To improve the coating property of the aqueous film-forming component (A).   The method according to claim 15, wherein the aqueous film-forming component (A) comprises an anionic surfactant (a2).