JP2007307823A - Reflective film laminated metal object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an environmental load and to demonstrate an excellent effect in terms of wet heat resistance in a reflective film laminated metal object in which a reflective film (C) is laminated on a metal sheet (A) through an adhesive (B). <P>SOLUTION: A urethane resin emulsion adhesive containing a polycarbonate diol urethane resin as a main component is used as the adhesive (B). The adhesive, for example, contains 100 pts.mass of the polycarbonate diol urethane resin, 5-30 pts.mass of a polyisocyanate, 1-20 pts.mass of a polycarbodiimide, and 1-5 pts.mass of a silane coupling agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a reflective film laminated metal body that can be used as a reflector such as a light reflecting mechanism (reflector) incorporated in an illumination device such as a fluorescent lamp, a display device or a copying machine.

  A reflective film made of a plastic film is lightweight and excellent in flexibility. Therefore, a reflective film laminated metal body obtained by bonding this to a metal plate such as an aluminum thin plate is subjected to press processing or the like. It is utilized as a reflector for a light reflector, a high light reflector for a fluorescent lamp, a reflector of a light reflector (reflector) of a liquid crystal display device, and the like.

  As this type of reflective film, conventionally, a reflective film obtained by adding an inorganic filler or an organic filler to a polyethylene terephthalate resin and stretched and foamed has been widely used because of its excellent light reflection performance and cost. However, in recent years, with higher performance of display devices, higher brightness has been demanded, and inorganic or organic fillers have been added to aliphatic polyester resins (for example, lactic acid polymers) with a low refractive index. Thus, a reflective film biaxially stretched and foamed has been proposed (see Patent Document 1).

  Moreover, as a reflective film laminated metal body, a reflector (plate) in which a white polyester film is bonded to a metal plate such as a stainless steel plate or an aluminum thin plate via an adhesive is known.

  For example, Patent Document 2 discloses a reflecting plate formed by laminating the reflecting layer made of a foamed white polyester film, an adhesive, and a metal plate in this order, and molding them into a predetermined shape.

  Patent Document 3 discloses a transparent polymer film (A), a silver thin film layer (B), an adhesive layer (C) made of a polyester adhesive having a glass transition temperature of 5 ° C. to 45 ° C., a metal made of aluminum or the like. A reflector having a reflective surface on the side of the transparent polymer film having the structure A / B / C / D composed of the support (D) is disclosed.

  Patent Document 4 discloses a light reflector formed by heat-sealing a white polyester film made of a polyester resin having at least one surface layer having a melting point of 160 ° C. to 240 ° C. with the polyester resin surface as an inner surface. Is disclosed.

  By the way, as a means for laminating a film on a metal plate, conventionally, a method of bonding via a thermosetting adhesive (including a solvent) such as an epoxy-based resin, a urethane-based resin, or a polyester-based resin has been generally used. There has been a movement to regulate the use of solvents due to contamination of the work environment and health problems of workers, and there is a shift to emulsion adhesives that do not use solvents (see, for example, Patent Documents 5 and 6).

WO200441077 JP-A-10-177805 Japanese Patent Laid-Open No. 10-206614 JP 2005-275256 A JP 2002-309216 A JP 2003-246974 A

  However, when a metal laminate and a reflective film are bonded together using an emulsion adhesive to form a reflective film laminated metal body, the conventional emulsion adhesive does not provide sufficient processability and is required for reflector applications. The sufficient heat and humidity resistance was not obtained.

  Therefore, in view of the above problems, the present invention can reduce the environmental burden in a reflective film laminated metal body having a configuration in which a reflective film is laminated on a metal plate via an adhesive, and is excellent in terms of moisture and heat resistance. It is an object of the present invention to provide a reflective film laminated metal body using an adhesive that can exert an effect.

  The present invention provides a reflective film laminated metal body having a configuration in which a reflective film (C) is laminated on at least one side of a metal plate (A) via an adhesive layer (B). A reflective film-laminated metal body is proposed in which the main component is a polycarbonate diol-based urethane resin.

  Here, the polycarbonate diol-based urethane resin is a urethane resin having a carbonate unit in the molecule, and the adhesive layer (B) mainly composed of this is an emulsion adhesive mainly composed of the polycarbonate diol-based urethane resin, For example, it can be formed from an emulsion adhesive containing a polycarbonate diol urethane resin as a main component and containing a crosslinking agent and a silane coupling agent.

  Thus, if a metal plate (A) and a reflective film (C) are bonded together using the emulsion adhesive which has a polycarbonate diol type urethane resin as a main component, without using a solvent, a metal plate (A) and Since the reflective film (C) can be bonded, it is possible not only to reduce the environmental burden, but also to make the reflective film laminated metal body excellent in moisture and heat resistance despite being an emulsion adhesive. be able to.

  In general, "film" is a thin flat product whose thickness is extremely small compared to the length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll. (Japanese Industrial Standard JISK6900), and “sheet” generally refers to a product that is thin according to the definition in JIS, and usually has a thickness that is small instead of length and width. However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish the two in terms of the present invention, in the present invention, even when the term “film” is used, the term “sheet” is included and the term “sheet” is used. In some cases, “film” is included.

Hereinafter, an example of an embodiment of the present invention will be described in detail, but the scope of the present invention is not limited to the embodiment described below.
In addition, in the present invention, the expression “main component” includes the intention to allow other components to be contained within a range that does not interfere with the function of the main component, unless otherwise specified. Although the content ratio of the components is not specified, the main component (when two or more components are the main components, the total amount thereof) is 50% by mass or more, preferably 70% by mass or more, particularly in the composition. It preferably includes 90% by mass (including 100%).
Further, when “X to Y” (X and Y are arbitrary numbers) is described, “X to Y” is intended unless otherwise specified, and “it is preferably larger than X and smaller than Y”. Includes intentions.

<This laminated metal plate>
The reflective film laminated metal body (hereinafter referred to as “the present laminated metal plate”) according to this embodiment has an adhesive layer (B) mainly composed of a polycarbonate diol-based urethane resin on one side or both sides of the metal plate (A). It is a reflective film laminated metal body provided with the structure formed by laminating | stacking a reflective film (C).

<Metal plate (A)>
The material of the metal plate (A) is not particularly limited, and examples thereof include various metals such as iron, various stainless steels, copper, copper alloys, aluminum, aluminum alloys, tin alloys, steel plates, nickel, and zinc. it can.

The surface of the metal plate (A) may be subjected to monolayer plating, multilayer plating or alloy plating, or may be subjected to immersion chromic acid treatment or phosphoric acid chromic acid treatment.
In addition, for the purpose of improving the adhesion to the adhesive layer (B), chemical treatment such as coupling agent treatment with silane coupling agent, titanium coupling agent, etc., acid treatment, alkali treatment, ozone treatment, ion treatment, plasma, etc. Various surface treatments such as surface treatments such as discharge treatment such as treatment, glow discharge treatment, arc discharge treatment, corona treatment, ultraviolet ray treatment, X-ray treatment, gamma ray treatment, laser treatment, flame treatment, and primer treatment May be given.

  The thickness of the metal plate (A) is 0.05 mm to 0.8 mm, but it is not limited to the metal plate having such thickness, and can be appropriately selected depending on the application.

<Adhesive layer (B)>
The adhesive layer (B) is an adhesive layer mainly composed of a polycarbonate diol urethane resin, and is a urethane resin emulsion adhesive (hereinafter also referred to as “the emulsion adhesive”) mainly composed of a polycarbonate diol urethane resin. Can be formed.

  In particular, the emulsion adhesive preferably contains a polycarbonate diol urethane resin as a main component (base resin) and contains a crosslinking agent and a silane coupling agent.

(Base resin)
The polycarbonate-based urethane resin as a base resin is a urethane resin having a carbonate unit in the molecule. For example, a polycarbonate diol, a compound having two or more hydroxyl groups and one or more carboxyl groups, an organic polyisocyanate, and, if necessary, chain extension It can be obtained by reacting an agent and / or a polymerization terminator.

Specific examples of the polycarbonate diol include polyhexamethylene carbonate diol.
The number average quantity of polycarbonate diol becomes like this. Preferably it is 300-5000, More preferably, it is 500-3000.

Examples of the compound having two or more hydroxyl groups and one or more carboxyl groups include dimethylol alkanoic acids such as dimethylol acetic acid, dimethylol propionic acid, and dimethylol butyric acid. Of these, dimethylolpropionic acid is preferred.
This compound is preferably contained in an amount of 5% by mass or less, more preferably about 0.1 to 4% by mass with respect to the polycarbonate diol.

To further enhance water dispersibility, sulfonate groups or carboxylate groups can be introduced (copolymerized) into the urethane polymer skeleton, but sulfonate groups are strongly acidic and maintain high-temperature moisture resistance due to their moisture absorption performance. Therefore, it is particularly preferable to introduce a weakly acidic carboxylate group in the present emulsion adhesive.
Specific examples of the salt forming agent include trialkylamines such as ammonia, trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, tri-n-butylamine, N such as N-methylmorpholine and N-ethylmorpholine. -N-dialkylalkanolamines such as alkylmorpholines, N-dimethylethanolamine, N-diethylethanolamine and the like. These can be used alone or in combination of two or more.

An organic polyisocyanate is an organic compound having an NCO group in its molecule, and isocyanurates and pellets derived from aliphatic diisocyanates, alicyclic diisocyanates, araliphatic diisocyanates, aliphatic diisocyanates, or alicyclic diisocyanates. Modified polyisocyanates and the like can be mentioned. Among these, aliphatic or alicyclic isocyanates are preferable from the viewpoint of yellowing resistance.
Specific examples of the aliphatic diisocyanate include hexamethylene diisocyanate and lysine diisocyanate. Specific examples of the alicyclic diisocyanate include cyclohexylmethane diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and the like. Likewise preferred are isocyanurates and pyret-modified polyisocyanates derived from aliphatic or alicyclic diisocyanates.

Specific examples of the chain extender include low molecular polyols and polyamines.
Examples of the low-molecular polyol include dihydric alcohols and their alkylene oxide low-mole adducts, bisphenol alkylene oxide low-mole adducts, trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane, and their low alkylene oxides. Mole adducts and the like can be mentioned.
Specific examples of polyamines include aliphatic polyamines such as ethylenediamine, N-hydroxyethylethylenediamine, tetramethylenediamine, hexamethylenediamine, and diethylenetriamine, 4,4'-diaminodicyclohexylmethane, 1,4-diaminocyclohexane, isophoronediamine, and the like. Alicyclic polyamines, xylylenediamine, α
, Α 1, α ′, α′- aliphatic polyamines having an aromatic ring such as tetramethylxylylenediamine, and aromatic polyamines such as 4,4′-diaminodiphenylmethane, tolylenediamine, benzidine and phenylenediamine. .
These may be used alone or in combination of two or more.

  Examples of the polymerization terminator include low-molecular monoalcohols such as methanol, butanol and cyclohexanol, and alkanolamines such as mono- and di-ethylamine, mono- and di-butylamine.

(Crosslinking agent)
In the present emulsion adhesive, it is preferable to use polyisocyanate and polycarbodiimide in combination as a crosslinking agent. In this case, by using polyisocyanate together, the carboxyl group and hydroxyl group of the urethane resin can be deactivated, and the high-temperature moisture resistance can be improved.
The addition amount of the crosslinking agent is preferably 6 to 50 parts, more preferably 5 to 30 parts with respect to 100 parts by mass of the polycarbonate diol urethane resin. If it is less than 6 parts, it becomes difficult to obtain the effect of improving the heat and moisture resistance, and if it exceeds 50 parts, it is difficult to obtain the effect of improving the heat and humidity resistance.

  The polyisocyanate as the crosslinking agent is preferably an organic polyisocyanate, that is, an organic compound having an NCO group in the molecule. For example, aliphatic diisocyanate, alicyclic diisocyanate, araliphatic diisocyanate, aliphatic diisocyanate, or fatty acid. Examples thereof include isocyanurates derived from cyclic diisocyanates, and pyret-modified polyisocyanates. Among these, aliphatic or alicyclic isocyanates are preferable from the viewpoint of yellowing resistance.

  Specific examples of the aliphatic diisocyanate include hexamethylene diisocyanate and lysine diisocyanate. Specific examples of the alicyclic diisocyanate include cyclohexylmethane diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and the like. Likewise preferred are isocyanurates and pyret-modified polyisocyanates derived from aliphatic or alicyclic diisocyanates.

  Specific examples of polyisocyanate as a crosslinking agent include Aquanate (trade name) manufactured by Nippon Polyurethane Industry Co., Ltd., Asahi Kasei Duranate (trade name), NK Assist (trade name) manufactured by Nikka Chemical Co., Ltd., Takenate manufactured by Mitsui Takeda Chemical Co., Ltd. (Product name), Elastolon (trade name) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and the like.

  The addition amount of the polyisocyanate as the crosslinking agent is preferably 5 to 30 parts with respect to 100 parts by mass of the polycarbonate diol urethane resin. If it is less than 5 parts, there is no effect of improving the moisture resistance, and if it exceeds 30 parts, not only a further improvement effect of the moisture resistance can be obtained, but the workability is lowered.

As the polycarbodiimide as the cross-linking agent, a compound having a carbodiimide group can be used, and as a commercially available product, for example, as monocarbodiimide using diphenylmethane diisocyanate (MDI) as a raw material, lupranate manufactured by BASF Corp. (product) Name), Stavaxol (trade name) manufactured by Sumitomo Bayer Urethane Co., Ltd., and polycarbodiimide using tetramethylxylylene diisocyanate as raw materials include Carbodilite (trade name) manufactured by Nisshinbo Co., Ltd.
The addition amount of the polycarbodiimide compound is preferably 1 to 20 parts with respect to 100 parts by mass of the polycarbonate diol urethane resin. When the amount is less than 1 part, there is no effect of improving the heat and moisture resistance. When the amount exceeds 20 parts, not only a further improvement effect of the heat and moisture resistance can be obtained, but the workability is lowered.

(Silane coupling agent)
Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2-aminoethyl) -3-aminopropylmethylmethoxy. Silane, 3-aminopropyl triethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-glycidoxypropyltri Methoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylpentamethyldisiloxane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxy Propyldimethylethoxysilane, (Γ-glycidoxypropyl) -bis- (trimethylsiloxy) methylsilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and the like. Of these, silane compounds having a glycidyl group or an amino group as a reactive group are preferred. Many of these silane coupling agents are commercially available and are readily available.
The addition amount of the silane coupling agent is preferably 1 to 5 parts with respect to 100 parts by mass of the polycarbonate diol urethane resin. When the amount is less than 1 part, the effect of improving the moist heat resistance is small, and when it exceeds 5 parts, the workability is deteriorated.

(Formulation example)
Here, as mentioned above, as a blending ratio when blending polyisocyanate, polycarbodiimide and silane coupling agent as the curing agent, the polyisocyanate is in a mass ratio with respect to 100 parts by mass of the polycarbonate diol-based urethane resin. It is preferable to adjust so as to contain 5 to 30 parts, 1 to 20 parts of polycarbodiimide, and 1 to 5 parts of a silane coupling agent.

(Preparation)
The preparation of the urethane emulsion is, for example, in the presence or absence of an organic solvent, a polycarbonate diol, a compound having two or more hydroxyl groups and two or more carboxyl groups, an organic polyisocyanate, and optionally a chain extender and / or A polymerization terminator is reacted by a one-step method or a multi-step method to prepare a carboxyl group-containing polycarbonate diol-based urethane resin, and then neutralizing the obtained carboxyl group-containing urethane-based resin with a salt-forming agent, Alternatively, it is mixed with water while neutralizing to form a dispersion (emulsion). Thereafter, the solvent can be removed as necessary to obtain a self-emulsifying urethane resin emulsion.
At this time, in order to promote the reaction, an amine catalyst used in a usual urethane resin forming reaction, or dioctyltin dimaleate, dibutyltin dilaurate, stannous octylate, dibutyltin oxide, bis (tri-n- Tin-based catalysts such as butyl tin oxide) can be used. In the case of using an organic solvent, a solvent that is water-soluble and has a boiling point comparable to or lower than that of water is preferable. Specific examples include acetone, methyl ethyl ketone, tetrahydrofuran, and dioxane.
Commercial products can also be used as these emulsion adhesives. For example, Evaphanol (trade name) manufactured by Nikka Chemical Co., Ltd., Superflex (trade name) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Yu Coat manufactured by Sanyo Kasei Kogyo Co., Ltd. Dick (trade name) can be listed.

  If necessary, a known additive may be contained. Examples of additives include pigments, fillers, aggregates, dispersants, dispersion stabilizers, wetting agents, thickeners, leveling agents, rheology control agents, antifoaming agents, plasticizers, film-forming aids, organic solvents, antiseptics Agents, pH adjusters, rust inhibitors, antioxidants, ultraviolet absorbers and the like.

(Adhesive properties)
The emulsion adhesive preferably has an elongation (JIS K 7127) of 300% or more, particularly 400% or more, from the viewpoint of processability and heat-and-moisture resistance. If the elongation is lower than 300%, peeling of the sheet tends to occur during press molding.
In order to increase the elongation of the emulsion adhesive to 300% or more, the molecular weight of the carbonate diol component and isocyanate component, and the addition amount of polyisocyanate and polycarbodiimide as a crosslinking agent for the carbonate diol urethane resin should be adjusted. That's fine.

Moreover, it is preferable that the acid value of this emulsion adhesive is 5 mg / g or more and less than 10 mg / g. If the acid value is less than 5 mg / g, it cannot be dispersed in water, and if the acid value is 10 mg / g or more, the hydrophilicity of the resin is too high. Unbearable.
Further, the hydroxyl value is preferably 15 mg / g or less.

<Reflection film (C)>
The material and structure of the reflective film (C) are not particularly limited as long as the film can function as a reflective film.
For example, even if the reflective film has a structure in which a filler such as titanium oxide is added to the base resin of the reflective film (C) and the reflective performance is obtained from refractive scattering due to the refractive index difference between the base resin and the filler, Even if it is a reflective film that has a structure in which a gap is provided in the film by stretching, foaming, etc., and the reflection performance is obtained from refractive scattering due to the difference in refractive index between the base resin and the gap (air), both of these structures are provided. It may be a reflective film or other reflective film.

  Examples of the base resin (main component) of the reflective film (C) include, but are not limited to, polyester resins, polyolefins, polycarbonates, and other transparent resins.

Among them, the polyester resin is one of resins preferable as the base resin of the reflective film (C), and as the polyester resin, aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, or an ester thereof, Ring opening of lactone such as aromatic polyester resin obtained by polycondensation with glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1.4 cyclohexanedimethanol, poly-ε-caprolactam, etc. Polymerized aliphatic polyester resin, polyethylene adipate, polyethylene azelate, polyethylene succinate, polybutylene adipate, polybutylene azelate, polybutylene succinate, polybutylene succinate adipate Polymerizing hydroxycarboxylic acid such as polytetramethylene succinate, cyclohexanedicarboxylic acid / cyclohexanedimethanol condensate, aliphatic polyester resin obtained by polymerizing dibasic acid and diol, lactic acid polymer, polyglycol, etc. Examples thereof include aliphatic polyester resins obtained and aliphatic polyesters in which part of ester bonds of the aliphatic polyester, for example, 50% or less of all ester bonds are replaced with amide bonds, ether bonds, urethane bonds, and the like.
Examples of aliphatic polyester resins fermented and synthesized by microorganisms include polyhydroxybutyrate, a copolymer of hydroxybutyrate and hydroxyvalerate, and the like.
In addition, since an aliphatic polyester resin that does not contain an aromatic ring in the molecular chain does not cause ultraviolet absorption, it is exposed to ultraviolet rays or by receiving ultraviolet rays emitted from a light source such as a liquid crystal display device. It does not deteriorate or yellow, and it is possible to suppress a decrease in light reflectivity over time.

  As the base resin of the reflective film (C), it is preferable to use a resin having a large difference in refractive index from air or a filler in order to obtain light reflectivity using refractive scattering. From this point, when mainly utilizing the refractive index difference from the filler, the base resin preferably has a smaller refractive index, and a lactic acid polymer having a refractive index (n) of less than 1.46 is particularly suitable. is there.

As a preferable reflective film (C), for example, a reflective film made of a foamed resin obtained by adding a filler to the base resin, and forming and stretching the film by a known method can be exemplified. Such a reflective film can obtain reflection performance from both the refractive scattering due to the refractive index difference between the base resin and the filler and the refractive scattering due to the refractive index difference between the base resin and the air gap (air). Light reflection performance can be realized.
In this case, examples of the filler include inorganic pigments such as barium sulfate, calcium carbonate, titanium oxide, alumina, zinc oxide, and magnesium hydroxide, hollow particles such as styrene, and organic fillers such as olefin resin. it can. Of these, calcium carbonate, barium sulfate, titanium oxide, zinc oxide and the like having a larger refractive index difference from the polyester resin are particularly preferable from the viewpoint of further improving light reflectivity.

  If necessary, the base resin may contain a known additive. For example, a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light resistance agent, an impact resistance improver, and the like may be contained.

  A known method may be adopted as the method for forming and stretching the reflective film (C). For example, it is possible to adopt a method (sequential biaxial stretching method) in which a film stretched by extrusion from a T-die is stretched in the longitudinal direction with a roll-type stretching machine and then stretched in the transverse direction with a tenter-type stretching machine. In addition, it is also possible to adopt a method (simultaneous biaxial stretching method) in which the end-stretched film is stretched simultaneously in the vertical and horizontal directions by a tenter type simultaneous biaxial stretching machine. It is also possible to employ a method (inflation method) in which a film melt-extruded in a tube shape is expanded by gas pressure and stretched, or other methods.

The reflective film (C) may have a multilayer structure for the purpose of further improving surface characteristics such as reflectance. For example, a highly reflective metal thin film layer containing Ag, Al, Sn or the like may be laminated.
Moreover, in order to improve adhesiveness and wettability, surface treatment such as corona treatment, coating treatment, or flame treatment may be performed.

  A commercially available product can also be used as the reflective film (C). For example, Lumirror E60L and E60V (trade name) manufactured by Toray Industries, Melinex (trade name) manufactured by Teijin DuPont, Crisper (trade name) manufactured by Toyobo Co., Ltd., Lef White (trade name) manufactured by Kimoto, Mitsubishi A white polyester film such as resin ecolog SW (trade name) can be used. However, it is not limited to these.

  The thickness of the reflective film (C) is not particularly limited, but is preferably in the range of 10 μm to 500 μm, for example, in terms of moldability and laminateability.

<Production method>
In the production of the laminated metal plate, for example, an adhesive is applied to one side of the metal plate (A), the metal plate (A) is heated, and the reflective film (C) is pressure-bonded to the adhesive side with, for example, a nip roll. Alternatively, an adhesive may be applied to one side of the reflective film (C), and the heated metal plate (A) may be pressure-bonded to the adhesive side.
In any case, a known method can be adopted as a method for applying the adhesive, such as an airless method, spray coating, dipping method, gravure coating, roll coating method, bar coating, brush coating method, and other known methods. These methods can be employed as appropriate.
The adhesive is preferably applied so that the thickness after drying is 0.5 μm to 10 μm, particularly 1 μm to 5 μm.
Furthermore, it is preferable to heat the metal plate (A) to a temperature range of 150 ° C to 230 ° C. If it is lower than 150 ° C., the adhesion strength is too weak and the reflective film may peel off. On the other hand, when the temperature is higher than 230 ° C., the adhesive deteriorates due to heat and the adhesion strength decreases, and the reflective film is cracked or peeled off due to impact during processing, and the reflective performance due to thermal damage to the reflective film. Cause a drop.

<Application>
This laminated metal plate can be suitably used as a reflecting plate of a lighting device such as a fluorescent lamp, a reflecting plate of a light reflecting mechanism (reflector) incorporated in a display device, a copying machine, or the like.
For example, as shown in FIG. 1, a cold cathode fluorescent lamp having a J-shaped cross section is formed by bending one side portion of the laminated metal plate so as to be folded back with the reflective film (C) inside. can do. The cold cathode tube reflector is configured such that the cold cathode tube is accommodated inside the folded portion, and the light guide plate is disposed so that the end portion of the light guide plate is in contact with the inside from the opening of the folded portion, A backlight mechanism (light guide plate method) of a liquid crystal display device can be configured.

Examples of the present invention will be described below and will be described in more detail. However, the present invention is not limited to these examples, and various applications are possible without departing from the technical idea of the present invention.
First, measurement values and evaluation measurement methods and evaluation methods shown in Examples and Comparative Examples will be described.

<Elongation>
The emulsion adhesive shown in Table 1 was pre-dried at room temperature for 15 hours, and then dried at 80 ° C. for 6 hours and 120 ° C. for 20 minutes to prepare a sheet having a thickness of 500 μm. And elongation at break was measured according to JIS K7127.

<Igata Eriksen workability>
According to JIS K 6744, when the extrusion amount is 4 mm and the well-shaped Erichsen process is performed, it is evaluated as x when there is peeling such as floating of the reflection film on the top, Δ when there is slight peeling, and ○ when there is no peeling. did.

<Bending workability>
A laminated plate made by laminating a reflective film (C) on a metal plate (A) through an adhesive layer (B) was cut into 30 mm x 120 mm, and a notch was made with a feather blade from the reflective sheet surface side. It was a piece. The reflective sheet surface was turned to the outer surface side, and bending was performed 180 ° at 0 ° C. according to JIS K 5400.
After bending, visually check the peeling of the reflective sheet surface, and when the area of the peeled surface is peeled off at the interface between the adhesive and the reflective film or at the metal plate and the adhesive interface is 30% or more, When it was 5% or more and less than 30% of the whole, it was evaluated as Δ, and when it was less than 5%, it was evaluated as ○.

<Heat and heat resistance>
A laminated plate obtained by laminating the reflective film (C) on the metal plate (A) via the adhesive layer (B) was cut into 60 mm × 60 mm and immersed in boiling water for 10 hours. Take out after 10 hours, if the area of the peeled part of the test piece is 10% or more of the whole, ×, if it is 5% or more and less than 10% of the whole, Δ, if it is less than 5% of the whole Evaluated as ○.

(Preparation of reflective film (C))
A pellet of a lactic acid polymer having a weight average molecular weight of 200,000 (D-form content: 0.5%, glass transition temperature: 65 ° C.) and titanium oxide having an average particle diameter of 0.25 μm are mixed at a mass ratio of 50:50. A master batch was prepared by pelletizing using a twin screw extruder.
The master batch and the lactic acid polymer were mixed at a mass ratio of 40:60 to prepare a resin composition. Thereafter, this resin composition was extruded from a T die at 220 ° C. using a single screw extruder, and cooled and solidified to form a film. The obtained film was biaxially stretched 3 times in the MD direction and 3 times in the TD direction at a temperature of 65 ° C. and then heat treated at 140 ° C. to obtain a biaxially stretched aliphatic polyester reflective film having a thickness of 80 μm.

(Test example)
An emulsion adhesive is prepared by blending the urethane-based resin (base resin) shown in Table 1 with the curing agent shown in Table 2, so that the coating thickness after drying is 3 μm on a stainless steel plate (SUS304) 0.1 mm. After the adhesive is applied to the substrate and dried at 80 ° C., the biaxially stretched aliphatic polyester reflective film is laminated on a stainless steel plate so as to be baked at 180 ° C. by a pair of laminating rolls. A reflective film laminated metal body was obtained.
Said evaluation was performed about the obtained reflective film laminated metal body, and the result was shown in Table 3.

  In addition, Mitsui Takeda Chemical Takenate WB420 (trade name) is used as the polyisosoyanate, and γ-glycidoxypropyltrimethoxysilane (TSL8350 (trade name, manufactured by GE Toshiba Silicone) is used as the silane coupling agent. Nisshinbo's carbodilite E01 (trade name) was used as the carbodiimide, and Epocross WS500 (trade name) manufactured by Nikka Chemical Co., Ltd. was used as the oxazoline.

From the results in Table 3, the following became clear.
When an adhesive mainly composed of a polycarbonate diol-based urethane resin was used (Example 1-13), the heat and moisture resistance was superior to that when a polyester-based urethane emulsion was used (Comparative Example 1).
However, when a urethane-based emulsion adhesive having an elongation lower than 300% was used (Example 13), there was a tendency for well-shaped Erichsen adhesion and notch bending workability to decrease.
In contrast, when a urethane emulsion adhesive having an elongation of 300% or more is used and an adhesive containing a predetermined amount of polyisocyanate, carbodiimide, and silane coupling agent is used (Example 1-5) ) Was excellent in all well-shaped Erichsen adhesion, bending workability, and moisture and heat resistance.

  The mode of Example 1-5 is less than that with a small amount of isocyanate added (Example 6), a small amount of silane coupling agent added (Example 7), and a small amount of carbodiimide added (Example 8). It was excellent in terms of heat and humidity resistance.

The aspect of Example 1-5 is superior in terms of moisture and heat resistance as compared with that having a large amount of isocyanate added (Example 9) and that having a large amount of carbodiimide added (Example 11), and adding a silane coupling agent Compared with a large amount (Example 10), it was excellent in terms of well-shaped Erichsen adhesion and notch bending workability.
Moreover, the aspect of Example 1-5 was excellent in terms of moisture and heat resistance, as compared with a case where a curing agent having an oxazoline group was added instead of carbodiimide (Example 12).

It is the figure which showed the structural example at the time of forming the reflective plate for cold cathode tubes using an example of the reflective film laminated metal body of this invention.

Claims (7)

  A reflective film laminated metal body having a configuration in which a reflective film (C) is laminated on at least one side of a metal plate (A) via an adhesive layer (B), the main component of the adhesive layer (B) Is a polycarbonate diol-based urethane resin.   The reflective layer according to claim 1, wherein the adhesive layer (B) is formed of an adhesive containing a polycarbonate diol-based urethane resin as a main component and a crosslinking agent and a silane coupling agent. Film laminated metal body.   The reflective film-laminated metal body according to claim 1, comprising polyisocyanate and polycarbodiimide as a crosslinking agent.   The adhesive layer (B) contains 5 to 30 parts of polyisocyanate, 1 to 20 parts of polycarbodiimide, and 1 to 5 parts of silane coupling agent with respect to 100 parts of the polycarbonate diol-based urethane resin. The reflective film laminated metal body according to any one of claims 1 to 3, wherein:   The reflective film laminated metal body according to any one of claims 1 to 4, wherein a main component of the reflective film (C) is a lactic acid polymer.   A reflector comprising the reflective film laminated metal body according to claim 1.   A reflector using the reflector according to claim 6.

Images