JP2009073984A - Acrylic resin film excellent in resistance to warm water whitening and laminated wall material of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film having improved resistance against warm water whitening, and to provide an acrylic resin film laminated wall material having resistance against warm water whitening, which is required as a laminated wall material frequently being in contact with warm water, by using the above film. <P>SOLUTION: An acrylic resin film having favorable resistance against warm water whitening can be obtained by decreasing micro-voids generating in the manufacturing process of a film comprising an acrylic resin, particularly, by decreasing micro-voids having major axes of less than 500 nm. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a wall material that is frequently contacted with hot water, such as a garage and a window frame, and has a wall material that prevents warm water whitening by laminating a specific acrylic resin film, and an acrylic resin film used in the application. It is about.

  Conventionally, as a wall material such as a garage and a window frame, a laminate of soft vinyl chloride on a steel plate called a vinyl chloride steel plate, a molded panel made of fiber reinforced resin (FRP), or the like has been used. A clear layer is generally formed on the outermost surface of these wall materials by a thermosetting resin such as diallyl phthalate resin or polyester resin, or by painting.

  On the other hand, recently, there is an increasing need for laminated wall materials that are affordable, easy to handle and excellent in design. These laminated wall materials are obtained by easily attaching a thermoplastic resin film having a clear layer or a printed layer to a base material. Among these, as a film material, acrylic resin is widely used because it is excellent in transparency and weather resistance, and can be laminated to various materials to prevent deterioration of the base material and maintain its beauty. Yes.

The wall material on which a clear layer used for conventional garages, window frames and the like is formed has the following problems. That is, a wall material such as a garage or a window frame, which has many opportunities to come into contact with hot water, has a problem that the acrylic resin film is whitened when water or hot water comes into direct contact during use. As a method of improving warm water whitening resistance, a method of adjusting the amount of calcium remaining in the acrylic resin film within a predetermined range (see Patent Document 1), and a method of adjusting the content of water-soluble substances to 200 ppm or less (Patent Document 2) ), Etc. have been made, but it was insufficient as an effect of improving warm water whitening resistance.
JP 2000-191804 A JP 2003-277528 A

  The present invention provides an acrylic resin film used for a laminated wall material having many opportunities to come into contact with warm water, and provides a film with improved warm water whitening resistance. Further, the film has many opportunities to come into contact with warm water. An object of the present invention is to provide an acrylic resin film laminated wall material having hot water whitening resistance required as a laminated wall material.

  In view of the prior art described above, the present inventors have conducted extensive research to develop an acrylic resin film excellent in hot water whitening resistance. As a result, a film made of an acrylic resin composition is produced during the production process. It has been found that an acrylic resin film having good hot water whitening resistance can be obtained by reducing microvoids, particularly by reducing microvoids whose major axis is less than 500 nm. Based on this knowledge, various studies were further added to complete the present invention.

That is, the present invention
A film formed by molding an acrylic resin composition, characterized in that the number of microvoids having a major axis of less than 500 nm contained in the film is 30/400 μm ² or less, and has excellent hot water whitening resistance Acrylic resin film (Claim 1),
The acrylic resin film excellent in hot water whitening resistance according to claim 1, wherein the film has a thickness of 20 to 600 μm (claim 2),
The acrylic resin film excellent in hot water whitening resistance according to claim 1 or 2, wherein the glass transition point of the acrylic resin composition constituting the film is 65 ° C or higher and lower than 100 ° C. ),
The warm water whitening resistance according to any one of claims 1 to 3, wherein the acrylic resin composition contains rubber elastic particles, and the rubber elastic particles have an average particle diameter of 10 nm or more and 300 nm or less. Acrylic resin film having excellent properties (Claim 4),
A laminated wall material (Claim 5), wherein the acrylic resin film excellent in hot water whitening resistance according to any one of Claims 1 to 4 is laminated on a substrate.
6. A laminated wall material (Claim 6) and a base on which an acrylic resin film is laminated, wherein printing is performed on one side of the acrylic resin film, and the printed surface is laminated on a substrate. The laminated wall material according to claim 5, wherein the material surface is printed (claim 7).
About.

  The acrylic resin film of the present invention is useful as a surface material for wall materials, such as window frames and garages, which have many opportunities to come into contact with hot water. Wall materials obtained by laminating the resin film on a base material are whitened by contact with hot water. Without raising, it maintains a design with excellent gloss and satisfies the quality required as a wall material over a long period of time. In addition, the process can be simplified and the product can be manufactured at a lower cost than when the surface is formed by clear coating.

  Hereinafter, the present invention will be described in detail.

  The acrylic resin film of the present invention is a film that can suppress whitening at the time of hot water contact by reducing microvoids having a major axis of less than 500 nm contained in an acrylic film formed by molding an acrylic resin composition. (Hereinafter referred to as “excellent in resistance to warm water whitening”).

  The major axis of the microvoid is the maximum diameter of the irregularly shaped white particles in the transmission electron micrograph taken after processing the acrylic resin film, which will be described later, by vapor staining with ruthenium tetroxide. This is a value measured using calipers.

  As the acrylic resin composition in the present invention, as described later, a resin composition in which rubber particles are dispersed in a methacrylic resin is preferable from the viewpoint of bending whitening.

The microvoids having a major axis of less than 500 nm contained in the acrylic resin film in the present invention are preferably 30 pieces / 400 μm ² or less, more preferably 20 pieces / 400 μm ² or less, and further preferably 10 pieces. / 400 μm ² or less, particularly preferably 5/400 μm ² or less. When the number of microvoids having a major axis of less than 500 nm exceeds 30/400 μm ² , whitening at the time of hot water contact tends to be significant.

  On the other hand, when a microvoid having a major axis of 500 nm or more is contained in the acrylic resin film, the transparency of the film tends to be impaired.

  In the present invention, the microvoids contained in the acrylic resin film can be quantified by a vapor staining method using ruthenium tetroxide.

  That is, it can be evaluated using a transmission electron micrograph of a film dyed by a ruthenium tetroxide vapor dyeing method. The vapor dyeing method with ruthenium tetroxide is a method of trimming the cross section (thickness direction) of the film, exposing the block, and fixing the ultra-thin section to the mouth of a dyeing bottle containing 2% ruthenium tetroxide solution. It is a method to implement. The staining time is set while confirming the degree of staining with a transmission electron microscope. When rubber particles are dyed, it becomes difficult to distinguish them from microvoids, so the dyeing time is preferably 15 minutes or less, more preferably 5 minutes or less.

The film after vapor dyeing is photographed at a magnification of 10,000 using a transmission electron microscope. From the obtained photograph, the number of microvoids whose major axis existing in an area of 400 μm ² is less than 500 nm is calculated. The micro voids in the obtained transmission electron micrograph are voids that appear as white particles and are caused by vaporization of volatile substances (low molecular weight decomposition products, air / water, etc.). In the transmission electron micrograph at this time, the rubber particles are not dyed.

  As a result of the study, the present inventors have found that the microvoids of the acrylic resin film expand when contacted with hot water, that is, the major axis becomes large, and as a result, the acrylic resin film is whitened. .

The microvoids after the hot water contact test in the present invention, the long axis is more than 500nm microvoids is preferably 3 or / 400 [mu] m ² or less, more preferably 1/400 [mu] m ² or less. When the number of microvoids having a major axis of 500 nm or more after the hot water contact test exceeds 3/400 μm ² , the film tends to whiten.
Here, the warm water contact test means that after the film is immersed in ion exchange water at 80 ° C. for 4 hours, water droplets adhering to the film surface are removed, and the temperature is 23 ° C. ± 2 ° C. and the humidity is 50% ± 5%. It is left for 1 hour.

  In the present invention, the method for reducing the microvoids contained in the acrylic resin film is not particularly limited, but the following method is preferably used.

  In the present invention, in order to reduce the microvoids contained in the acrylic resin film, it is preferable to sufficiently remove the low molecular weight decomposition products generated by thermal decomposition during pellet production. Since this low molecular weight decomposition product is a water-insoluble substance, it is difficult to remove it by washing with water, and suction removal by a vent during extrusion molding is effective.

  In the present invention, in order to reduce microvoids contained in the acrylic resin film, it is also preferable to sufficiently remove mixed air and moisture. Suction removal by venting at the time of extrusion is also effective for removing mixed air and moisture. At that time, the longer the L / D (cylinder length / screw diameter) of the extrusion molding machine, the more back pressure is applied, and the suction removal becomes more efficient.

  In the suction removal by vent, if the balance between the screw supply amount and the extrusion amount is lost, the resin will be deposited in the vent holes existing between them and suction removal cannot be performed, so it is important to keep this balance constant. It becomes. It is useful to install two or more vent holes in the extruder. If two vent holes are installed, the zone between the vent holes can be sucked efficiently.

  Although the thickness of the acrylic resin film in this invention is not specifically limited, 20-600 micrometers is preferable and 30-200 micrometers is more preferable. A film thickness of 20 μm or more is preferable because sufficient surface hardness can be obtained. On the other hand, when the thickness is 600 μm or less, the lamination with the base material can be easily processed by increasing the rigidity, which is preferable.

  The cloudiness (haze) of the acrylic resin film in the present invention is preferably 10% or less, and more preferably 3% or less. Here, the haze is a value measured at a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5% in accordance with JIS K7136.

  The haze after the hot water contact test of the acrylic resin film in the present invention is preferably 20% or less, and more preferably 10% or less. Here, the haze after the hot water contact test is that the film is immersed in ion-exchanged water at 80 ° C. for 4 hours, then drops of water adhering to the film surface are removed, and the temperature is 23 ° C. ± 2 ° C. and the humidity is 50%. It is a value measured after standing for 1 hour in an environment of ± 5%.

  The pencil hardness of the acrylic resin film in the present invention is preferably 3B or more, and more preferably 2B or more.

  The glass transition point of the acrylic resin composition in the present invention is not particularly limited, but is preferably 65 ° C. or higher and lower than 100 ° C., more preferably 80 ° C. or higher and 98 ° C. or lower. Films used for laminated wall materials need to be folded because they are laminated into a complicated shape by laminating, and those with a high glass transition point of acrylic resin compositions tend to cause stress whitening and cracking There is. Therefore, by making the glass transition point of the acrylic resin composition within the above range, the surface hardness and the adhesion processability with the substrate can be made excellent. It is preferable for the glass transition point to be less than 100 ° C., because the flexibility increases and the laminating process with the base material can be easily performed. On the other hand, when the glass transition point of the acrylic resin composition is 65 ° C. or more, it is preferable because sufficient surface hardness can be obtained.

  The rubber particles dispersed in the acrylic resin composition of the present invention are not particularly limited, but the average particle size is preferably in the range of 0.01 to 0.3 μm, and in the range of 0.01 to 0.2 μm. It is more preferable that it is in the range of 0.03 to 0.1 μm. When the average particle diameter of the rubber particles is in the above range, a film having high impact resistance, excellent surface hardness, and smooth surface can be obtained. When the average particle diameter of the rubber particles is less than 0.01 μm, the surface hardness of the film is lowered and the film tends to be brittle. On the other hand, when the average particle diameter exceeds 0.3 μm, the transparency of the film tends to be impaired. The average particle size of the rubber particles can be adjusted by adjusting the amount of surfactant added in emulsion polymerization described later, the amount of monomer charged, and the like.

  The rubber particles in the present invention are obtained, for example, by polymerizing a monomer mixture (b) containing an alkyl acrylate ester as a main component and a crosslinkable monomer by an emulsion polymerization method or the like in at least one stage reaction. In the presence of the elastic copolymer (B), the monomer mixture (a) containing a methacrylic acid ester as a main component can be produced by polymerizing by at least one stage reaction by an emulsion polymerization method or the like. By such multi-stage polymerization, the monomer mixture (a) mainly composed of a methacrylic acid ester used in the subsequent stage is graft-copolymerized to the elastic copolymer (B), and a grafted elastomer-containing graft having a graft chain is obtained. A copolymer (G) is produced. That is, the rubber particles in the present invention become a graft copolymer (G) having a multilayer structure including an elastic copolymer mainly composed of alkyl acrylate.

  In the rubber particles, examples of the acrylic acid alkyl ester used in the monomer mixture (b) for constituting the elastic copolymer (B) include those having an alkyl group having 1 to 8 carbon atoms. Of these, alkyl groups having 4 to 8 carbon atoms such as butyl acrylate and 2-ethylhexyl acrylate are preferable. Here, the main component of acrylic acid ester is 50% by weight or more, preferably 60% by weight or more when the entire monomer mixture (b) is 100% by weight.

  In the monomer mixture (b) for constituting the elastic copolymer (B), other vinyl monomers copolymerizable with the acrylate ester used as needed are contained in one molecule. Monofunctional compound having one polymerizable carbon-carbon double bond, specifically, methacrylic acid ester such as methyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, and aromatic vinyl compound such as styrene And vinylcyan compounds such as acrylonitrile.

  The copolymerizable crosslinkable monomer used in the monomer mixture (b) for constituting the elastic copolymer (B) has at least two polymerizable carbon-carbon double bonds in one molecule. For example, unsaturated carboxylic acid diesters of glycols such as ethylene glycol dimethacrylate and butanediol dimethacrylate, alkenyls of unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate and allyl cinnamate Esters, polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, unsaturated carboxylic acid esters of polyhydric alcohols such as trimethylolpropane triacrylate, divinylbenzene And so on.

  Examples of the alkyl methacrylate used in the monomer mixture (a) to be graft-copolymerized in the rubber particles include, for example, alkyl groups such as methyl methacrylate, ethyl methacrylate, butyl methacrylate having 1 to 4 carbon atoms. Among them, methyl methacrylate is preferable. Here, the methacrylic acid alkyl ester as a main component is 50% by weight or more, preferably 60% by weight or more when the entire monomer mixture (a) is 100% by weight.

  Another vinyl monomer copolymerizable with the methacrylic acid ester used as necessary in the monomer mixture (a) has one polymerizable carbon-carbon double bond in one molecule. Monofunctional compounds, specifically, acrylic acid esters having an alkyl group having 1 to 8 carbon atoms such as methyl acrylate, ethyl acrylate, and butyl acrylate, aromatic vinyl compounds such as styrene, acrylonitrile And vinyl cyanide compounds.

  In the subsequent polymerization of the rubber particles, a component of the monomer mixture (a) that becomes an ungrafted polymer without undergoing a graft reaction with the crosslinked elastic body (B) is generated. The component constitutes part or all of the methacrylic resin described later.

  In the subsequent polymerization of the rubber particles, it is preferable to use a chain transfer agent during the polymerization in order to obtain a suitable glass transition temperature or to obtain a reduced viscosity exhibiting a suitable formability to a film. What is necessary is just to determine the quantity of a chain transfer agent suitably according to the kind and composition of a monomer.

  The methacrylic resin in the present invention is not particularly limited, but more specifically, a methacrylic resin obtained by polymerizing a monomer mixture mainly composed of an alkyl methacrylate having 1 to 4 carbon atoms. A copolymer is preferred.

  Examples of the methacrylic acid alkyl ester used in the monomer mixture for producing the methacrylic resin include those having 1 to 4 carbon atoms in the alkyl group such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Of these, methyl methacrylate is preferred. Here, the main component of methacrylic acid ester is 50% by weight or more, preferably 60% by weight or more when the entire monomer mixture is 100% by weight.

  Other vinyl monomers that can be copolymerized with the alkyl methacrylate are used as necessary in the monomer mixture for producing the methacrylic resin, and a polymerizable carbon-carbon double bond is contained in one molecule. Specifically, it is a monofunctional compound having an alkyl group, specifically, an alkyl acrylate ester having an alkyl group having 1 to 8 carbon atoms such as methyl acrylate, ethyl acrylate, or butyl acrylate, or an aromatic such as styrene. Group vinyl compounds, vinylcyan compounds such as acrylonitrile, and the like.

  The polymerization method of the methacrylic resin in the present invention is not particularly limited, and can be performed by a usual method such as suspension polymerization, emulsion polymerization, bulk polymerization and the like.

  In the polymerization of the methacrylic resin, it is preferable to use a chain transfer agent in order to obtain a suitable glass transition temperature or to obtain a reduced viscosity showing a moldability to a suitable film. What is necessary is just to determine the quantity of a chain transfer agent suitably according to the kind and composition of a monomer.

  In the emulsion polymerization or suspension polymerization of rubber particles or methacrylic resins in the present invention, a normal polymerization initiator can be used. Specific examples of the polymerization initiator include inorganic peroxides such as potassium persulfate and sodium persulfate, organic peroxides such as cumene hydroperoxide and benzoyl peroxide, and oil solubility such as azobisisobutyronitrile. An initiator is also used. These may be used alone or in combination of two or more. These initiators are combined with reducing agents such as sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, hydroxyacetone acid, ferrous sulfate, ferrous sulfate and disodium ethylenediaminetetraacetate Moreover, you may use as a normal redox type | mold initiator.

  The surfactant used for the polymerization is not particularly limited, and any surfactant for normal emulsion polymerization can be used. Specific examples of surfactants include anionic surfactants such as sodium alkyl sulfate, sodium alkylbenzene sulfonate, sodium dioctyl sulfosuccinate, sodium lauryl sulfate, alkylphenols, aliphatic alcohols and propylene oxide, ethylene Nonionic surfactants such as reaction products with oxides are shown. These surfactants may be used alone or in combination of two or more. Furthermore, if necessary, a cationic surfactant such as an alkylamine salt may be used.

  The resin composition is separated and recovered from the rubber particles or methacrylic resin polymer latex obtained by the polymerization method as described above by ordinary coagulation and washing, or by treatment such as spraying or freezing.

  As content of the rubber particle in the acrylic resin composition in this invention, when the total amount of methacrylic resin and rubber particle is 100 weight%, the range of 5-65 weight% is preferable, and 15-60 weight% Is more preferable, and the range of 20 to 60% by weight is more preferable. When the content of the rubber particles is less than 5% by weight, the bending whitening resistance tends to decrease. When the content of the rubber particles exceeds 65% by weight, the heat resistance is lowered or blocking is likely to occur and the film surface tends to be non-uniform.

  The acrylic resin film in which rubber particles are dispersed in the acrylic resin in the present invention is a normal additive such as an ultraviolet absorber, organic dye, pigment, inorganic dye, antioxidant, antistatic agent, surfactant, etc. It may contain.

  Especially, an ultraviolet absorber is preferably used when improving a weather resistance.

  Examples of the ultraviolet absorber in the present invention include commonly used benzotriazole-based ultraviolet absorbers, 2-hydroxybenzophenone-based ultraviolet absorbers, and salicylic acid phenyl ester-based ultraviolet absorbers. Specifically, as a benzotriazole ultraviolet absorber, 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol] 2- (5-methyl-2-hydroxyphenyl) -2H-benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- ( 3,5-di-tert-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2 -(3,5-di-tert-butyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3,5-di-tert-a Examples include mil-2-hydroxyphenyl) -2H-benzotriazole, 2- (2'-hydroxy-5'-tert-octylphenyl) -2H-benzotriazole. Specific examples of 2-hydroxybenzophenone-based ultraviolet absorbers include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy-4 Examples include '-chlorobenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and the like. Specific examples of salicylic acid phenyl ester ultraviolet absorbers include p-tert-butylphenyl salicylic acid ester and p-octylphenyl salicylic acid ester. These ultraviolet absorbers may be used alone or in combination of two or more.

  In this invention, when mix | blending a ultraviolet absorber, the compounding quantity is 0.1-3 weight part normally with respect to a total of 100 weight part of a methacryl resin and a rubber particle, Preferably it is 0.3-3. Parts by weight.

  In the present invention, an acrylic resin film is produced by mixing the methacrylic resin and rubber particles described above and forming an acrylic resin composition containing other additives as necessary.

  As a method for producing the acrylic resin film in the present invention, any method such as a melt casting method, a melt extrusion method such as a T-die method or an inflation method, or a calendar method may be used. Among these, the above acrylic resin composition is melt-extruded from, for example, a T-die, and the method of forming a film by bringing at least one surface of the obtained film-like material into contact with a roll or a belt is a film having good surface properties. It is preferable at the point obtained. In particular, from the viewpoint of improving the surface smoothness and surface gloss of the film, the film-like product obtained by melt extrusion molding the acrylic resin composition is brought into contact with the roll surface or belt surface to form a film. The method is preferred. The roll or belt used at this time is preferably made of metal. Furthermore, it is preferable that the roll has a mirror surface. Therefore, as a preferred embodiment, after the acrylic resin composition containing the methacrylic resin and rubber particles is melt-extruded from a T die, it is brought into contact with at least one mirror roll, more preferably in contact with two mirror rolls. A method of forming a film in a state of being sandwiched between them is mentioned.

  The acrylic resin film of the present invention may be colored. As a coloring method, the resin composition itself of methacrylic resin and rubber particles contains a pigment or a dye, and the resin composition itself before film formation is colored. The acrylic resin film is immersed in a liquid in which the dye is dispersed. Although there are dyeing methods for coloring, there is no particular limitation.

  The acrylic resin film of the present invention can also be formed with a design layer by printing a pattern or the like on at least one surface thereof or providing a colored layer. These design layers are preferably applied to the side in contact with the base material constituting the laminated wall material in order to give a deep appearance.

  In the acrylic resin film of the present invention, at least one layer made of another thermoplastic resin may be laminated on one side. When a design layer such as printing or coloring is provided on one surface of the acrylic resin film, another resin is laminated on the surface.

  As a method of integrally molding with other thermoplastic resins, for example, an acrylic resin film and a thermoplastic resin are separately formed in advance into a film shape, and laminated continuously between heating rolls, using a press. The method of thermocompression bonding, the method of laminating at the same time as compressed air or vacuum forming, the method of laminating with an adhesive layer (wet lamination), the other resin film that has been pre-formed and melt extruded from a T-die The method of laminating etc. is mentioned. When these methods are used, the acrylic resin molded into a film shape may be subjected to, for example, corona treatment or the like on the surface to be bonded to the other thermoplastic resin substrate. A layer may be provided. Further, another thermoplastic resin film on which printing has been performed can be laminated. A resin film having high compatibility with an acrylic resin such as a polyvinyl chloride resin may be directly laminated with the acrylic resin film. In addition, a resin that is incompatible with an acrylic resin, such as a polyolefin resin, requires an adhesive with an acrylic resin film. If the other thermoplastic resin laminated on one side is colored, the acrylic resin film remains colorless and transparent, and the base material of the laminated wall material is pasted and synthesized on the colored resin side, the depth It can be set as the outstanding decorating member which exhibits a coloring state with a feeling.

  Examples of the thermoplastic resin suitable for lamination with the acrylic resin film include polycarbonate resin, polyethylene terephthalate resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, other (meth) acrylic resins, ABS (acrylonitrile- Butadiene-styrene copolymer) resin and the like.

  By laminating the acrylic resin film of the present invention described above on a base material, an acrylic laminated wall material that is effective outdoors such as a garage and a window frame and has many opportunities to come in contact with hot water can be obtained.

  In order to impart a design such as a color pattern to the laminated wall material, by preparing a decorated acrylic resin film in advance, the number of steps when producing the laminated wall material is shortened and deep. Transparency can be achieved. For example, a method of printing on one side of an acrylic resin film and laminating the substrate on the side of the printed surface with or without an adhesive layer; A method of laminating a film and laminating on a substrate on another side of the printed film with or without an adhesive layer; coating one side of an acrylic resin film, with an adhesive layer or A method of laminating on the base material on the coated surface side can be adopted without intervention.

  As a base material constituting the laminated wall material, various conventionally known materials such as rock wool board, calcium silicate board, plastic board, steel plate, sandwich material with urethane foam sandwiched between steel plates, etc. Can be used.

  The laminated wall material thus obtained is in a state in which the acrylic resin film of the present invention is laminated on the outermost layer, and has excellent design properties such as depth and surface hardness as well as excellent resistance to hot water whitening. Become.

  These laminated wall materials can be used for applications with many opportunities to come in contact with hot water such as bathrooms, kitchens, toilets, toilets, and car exteriors.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples. In the examples, “%” and “part” representing the content or amount used are based on “% by weight” and “part by weight” unless otherwise specified.

(Explanation of abbreviations)
BA: butyl acrylate MMA: methyl methacrylate CHP: cumene hydroperoxide tDM: tertiary decyl mercaptan AlMA: allyl methacrylate OSA: sodium dioctylsulfosuccinate

  The evaluation method in the present invention is as follows.

(Evaluation of polymerization conversion)
The obtained acrylic resin composition (G) latex was dried in a hot air dryer at 120 ° C. for 1 hour to determine the solid content, polymerization conversion (%) = 100 × solid content / charged monomer (%) Calculated by

(Evaluation of average particle diameter of latex)
A sample obtained by diluting the obtained acrylic resin composition (G) latex to a solid content concentration of 0.02%, at a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5%, a spectrophotometer (manufactured by HITACHI, The average particle diameter is determined from the light transmittance at a wavelength of 546 nm using Spectrophotometer U-2000).

(Measurement of water content)
The moisture content is measured according to JIS K0113 (potential difference, current, electricity, Karl Fischer titration general rules).

(Evaluation of glass transition point)
The glass transition point of the sample film is measured according to a method defined in JIS K7121.

(Evaluation of haze value of film)
As for transparency of the obtained film, haze (cloudiness value) was measured at a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5% in accordance with JIS K7136.

(Surface property of film)
The surface property of the obtained film was evaluated according to the following criteria.
○: The surface is uniform and die line and fish eyes are not recognized.
Δ: The surface is uneven and die lines, burns, fish eyes, etc. are observed.
X: The surface is uneven and die lines, burns, fish eyes, etc. are remarkable.

(Evaluation of hot water whitening resistance)
The obtained film was immersed in ion exchange water at 80 ° C. for 4 hours to remove water droplets adhering to the film surface, and allowed to stand in an environment of temperature 23 ° C. ± 2 ° C. and humidity 50% ± 5% for 1 hour. The haze (cloudiness value) is measured according to JIS K7136.

(Evaluation of the presence of microvoids in the film)
Microvoids are evaluated by transmission electron micrographs obtained by vapor staining of ruthenium tetroxide.
The vapor dyeing method using ruthenium tetroxide involves trimming the cross section (thickness direction) of the film and bringing the ultrathin section (thickness 80 nm), which is the exposed block, into close contact with the mouth of a dyeing bottle containing 2% ruthenium tetroxide solution. Fix and perform staining. The staining time is set while confirming the degree of staining with a transmission electron microscope. When rubber particles are dyed, it becomes difficult to distinguish them from microvoids, so the dyeing time is 5 minutes or less.
After fixing the ultra-thin section after vapor staining to a collodion membrane applied mesh (Nisshin EM Co., Ltd., carbon reinforced product), using a transmission electron microscope (JEM-1200EX manufactured by JEOL Ltd.) Images were taken at an acceleration voltage of 80 kV and a magnification of 10,000 times. From the obtained photograph, the major axis of microvoids in an area of 400 μm ² is measured, and the number is calculated.
Note that the microvoids in the obtained transmission electron micrographs (see FIGS. 1 and 2) are white particles, and the white particles are voids due to vaporization of a volatile substance. In the transmission electron micrograph at this time, the rubber particles are not dyed.
Further, the major axis of the microvoid is a value obtained by measuring the maximum diameter of the irregularly shaped white particles in the transmission electron micrograph using a caliper.

(Evaluation of pencil hardness)
The pencil hardness of the obtained film was measured according to JIS K5600-5-4.

(Evaluation of bending whitening / cracking of film)
The obtained film (length 300 mm × width 100 mm) was bent 90 degrees at 0 ° C., and the change in the bent portion was visually evaluated.
[Whitening]
○: Whitening is not recognized.
X: Whitening is recognized.
[Crack]
○: No cracks are observed.
X: A crack is recognized.

(Evaluation of bending whitening / cracking of laminated materials)
The obtained film (length 300 mm × width 100 mm) was applied to a 0.5 mm-thick steel plate (length 300 mm × width 100 mm) with an adhesive [Takelac A695 as the main agent and Takenate A95 as the curing agent (both Mitsui Using Takeda Chemical Co., Ltd.) in a mass ratio of 6:10 (main agent: curing agent)], a bonded sample was obtained.
The obtained sample was bent 90 degrees at 0 ° C. with the film surface facing outward, and the change in the bent portion was visually evaluated.
[Whitening]
○: Whitening is not recognized.
X: Whitening is recognized [crack]
○: No cracks are observed.
X: A crack is recognized.

  The acrylic resin film of this invention was produced through the manufacturing process of the following acrylic resin powder products (G), a blending process, a pelletizing process, and a film forming process.

[Manufacturing process of acrylic resin powder]
(Production Example 1) Production of Acrylic Acrylic Resin Powder (G-1) The following substances were charged into an 8L polymerization apparatus with a stirrer.
Ion-exchanged water 200 parts Sodium dioctylsulfosuccinate (OSA) 0.6 parts sodium formaldehyde sulfoxylate 0.15 parts ethylenediaminetetraacetic acid-2-sodium 0.001 parts ferrous sulfate 0.00025 parts Polymerization After the inside of the machine was sufficiently replaced with nitrogen gas to make it substantially free of oxygen, the internal temperature was set to 40 ° C., and the mixture (b-1) shown in Table 1 (Production Example 1) [that is, BA 10% and 30 parts of a mixture comprising 1 part of AlMA and 0.2 part of CHP] per 100 parts of a mixture comprising 90% of MMA], and after the addition is completed, the polymerization is continued for another 0.5 hours, The polymerization conversion rate was 99.5%.
Thereafter, the mixture (b-2) shown in Table 1 (Production Example 1) [that is, 30 parts of a mixture of 0.1 part of CHP to 100 parts of a mixture of 50% BA and 50% MMA] was 10 parts / hour. The mixture was continuously added at a ratio, and the polymerization was further continued for 1 hour to obtain acrylate-based crosslinked elastic particles (B). The polymerization conversion rate was 98.7%.
Thereafter, the internal temperature was changed to 80 ° C., and the mixture (a-2) shown in Table 1 (Production Example 1) [that is, 40 parts of a mixture comprising 0.1 part of tDM with respect to 100 parts of a mixture comprising 10% BA and 90% MMA] ] Was continuously added at a rate of 10 parts / hour, and polymerization was further continued for 1 hour to obtain an acrylic resin composition (G). The polymerization conversion rate was 98.0%.
The obtained latex was salted out and coagulated with an aqueous calcium chloride solution, washed with water and dried to obtain an acrylic resin powder (G-1).

(Production Examples 2-3)
Production Examples 2 to 3 were polymerized in the same manner as in Production Example 1 except that the composition of the monomer mixture and the surfactant amount were changed as shown in Table 1, solidified, washed with water, and dried to obtain an acrylic resin powder ( G-2) to (G-3) were obtained.

[Blend process]
To 100 parts of the obtained acrylic resin powder (G-1), 2 parts of Tinuvin P (manufactured by Ciba Specialty Chemicals) as an ultraviolet absorber is added and mixed uniformly using a supermixer, and the powder mixture (P -1) was obtained.
About powder mixture (P-2)-(P-3), except having changed the acrylic resin powder seed | species as shown in Table 2, it mixes uniformly with a super mixer in the same procedure as P-1, and a powder mixture is obtained. It was.
As for the powder mixture (P-4), 20 parts of the acrylic resin powder (G-2) obtained in Production Example 2 and a methacrylic resin (Sumitex Chemical Industries, Sumipex MM, MMA / EA = 94/6). (Weight ratio, bead type) 80 parts of Tinuvin P was added and mixed uniformly using a super mixer to obtain a powder mixture.
Regarding the powder mixture (P-5), 95 parts of the acrylic resin powder (G-1) obtained in Production Example 1 and rubber particles (manufactured by Kaneka Corporation, Kane Ace M-210, particle diameter of elastic polymer 350 nm) To 5 parts, 2 parts of tinuvin P was added and mixed uniformly using a super mixer to obtain a powder mixture.

[Pellet process]
The obtained undried powder mixtures (P-1) to (P-5) were subjected to a cylinder temperature of 240 ° C. and a residence time of 7 minutes using a vented 40 mmφ single screw extruder (L / D = 30). Melting and kneading were performed under the conditions, and pelletized to obtain an acrylic resin-based pellet (D).
At the time of pellet extrusion of (D-1) to (D-5), suction from a vent capable of removing volatile components (the degree of vacuum of the vent, 0.93 MPa) was performed. For the other pellet extrusions (D-6) to (D-10), suction from the vent is not performed.
In addition, the undried powder mixture absorbed moisture and had a water content of 3000 to 4000 ppm.

[Filming process]
The acrylic resin pellets (D) thus obtained were subsequently extruded through a T-die having a set temperature of 205 ° C. using a 40 mmφ single-screw extruder so that the acrylic resin pellets (D) did not absorb moisture. A film (F) was obtained.
The properties of the obtained film were evaluated, and the results are shown in Table 4.

(Examples 1-6)
Examples 1 to 6 are films using pellets produced by removing volatile components by vent suction in the pellet process.
In Examples 1 to 6, the abundance of microvoids having a major axis of less than 500 μm is small, and the haze value of the film after the hot water whitening test is small. Further, in the film after the hot water whitening test, there are almost no microvoids having a major axis of 500 μm or more.

(Comparative Examples 1-5)
Comparative Examples 1 to 5 are films using pellets produced without performing volatile component removal by vent suction in the pellet process.
In the comparative example, there are many microvoids having a major axis of less than 500 μm, and the haze value of the film after the hot water whitening test is large. In the film after the hot water whitening test, there were many microvoids having a major axis of 500 μm or more.

The transmission electron micrograph (magnification: 10,000 times, photograph 1) of the sample dye | stained with the ruthenium tetroxide vapor dyeing | staining method with respect to the ultra-thin section of the acrylic resin film obtained in Example 1 is shown. The transmission electron micrograph (magnification: 10,000 times, photograph 2) of the sample dye | stained with the ruthenium tetroxide vapor dyeing | staining method with respect to the ultra-thin section of the acrylic resin film obtained by the comparative example 1 is shown.

Claims (7)

A film formed by molding an acrylic resin composition, characterized in that the number of microvoids having a major axis of less than 500 nm contained in the film is 30/400 μm ² or less, and has excellent hot water whitening resistance Acrylic resin film.   2. The acrylic resin film excellent in warm water whitening resistance according to claim 1, wherein the film has a thickness of 20 to 600 [mu] m.   The acrylic resin film excellent in hot water whitening resistance according to claim 1 or 2, wherein the acrylic resin composition constituting the film has a glass transition point of 65 ° C or higher and lower than 100 ° C.   The warm water whitening resistance according to any one of claims 1 to 3, wherein the acrylic resin composition contains rubber elastic particles, and the rubber elastic particles have an average particle diameter of 10 nm or more and 300 nm or less. Acrylic resin film with excellent properties.   A laminated wall material, wherein the acrylic resin film excellent in hot water whitening resistance according to any one of claims 1 to 4 is laminated on a base material.   6. The laminated wall material according to claim 5, wherein printing is performed on one side of the acrylic resin film, and the printed side is laminated on a base material.   The laminated wall material according to claim 5, wherein printing is performed on a surface of a base material on which the acrylic resin film is laminated.

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