JP5890298B2 - Adhesive and optical film using the same - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive whose transmission of visible light is adjusted, and relates to an optical film using the pressure-sensitive adhesive.

In recent years, in addition to personal computers and televisions, smartphones and tablets, or lighting devices that use light-emitting diodes (hereinafter referred to as LEDs) are rapidly penetrating, and the frequency of prolonged exposure to artificial light sources is increasing. . Of visible light emitted from these light sources, light in the blue region with a short wavelength of about 380 to 500 nanometers (hereinafter referred to as blue visible light) has been attracting attention as a possible problem for eye health. It is said that blue visible light has the property closest to ultraviolet rays among visible light, and therefore has the highest energy and is not absorbed by the cornea or lens of the eye, so that light reaches the retina and is likely to damage the photoreceptor cells.
Conventionally, as a technique for solving the above-described problem, an invention has been proposed in which a light-emitting portion of a white light-emitting device is provided with a spectrum removing unit including a filter (for example, see Patent Document 1).

However, in the spectrum removing means comprising the filter in the prior art,
Since the light emitting light source is directly provided, there is a problem in that a means for easily removing blue visible light cannot be provided at an arbitrary position.

JP 2008-311532 A

  This invention is made | formed in view of the above problems, and can provide the adhesive which cuts blue visible light and was excellent in durability. Moreover, it aims at providing the optical film which can be easily affixed on arbitrary positions with respect to blue visible light radiation | emission objects, such as an LED light source, using this adhesive.

(1) The adhesive of the present invention contains an adhesive resin and a blue visible light absorber having a maximum absorption wavelength at 380 to 500 nanometers, and the blue visible light absorber is based on 100 parts by mass of the adhesive resin. 0.001 to 0.05 parts by mass, and it does not contain a near-infrared absorber and a dye having a maximum absorption at a wavelength of 570 to 610 nm .
(2) Further, the optical film of the present invention is characterized in that the pressure-sensitive adhesive (1) is laminated on a translucent substrate .
(3) Moreover, the optical film of this invention is used for the illuminating device which used the optical film of said (2) for the light emitting diode, It is characterized by the above-mentioned .

  The pressure-sensitive adhesive of the present invention can absorb blue visible light from an LED light source. Therefore, visible light harmful to the human body can be absorbed, and a blue visible light emitting object such as an LED light source can be safely observed. Moreover, the optical film which can be easily affixed on blue visible-light radiation | emission objects, such as an LED light source, using this adhesive can be provided.

2 is a view showing a transmission spectrum of the pressure-sensitive adhesive of Example 1. FIG. 6 is a view showing a transmission spectrum of the pressure-sensitive adhesive of Example 2. FIG. 6 is a view showing a transmission spectrum of the pressure-sensitive adhesive of Example 3. FIG.

Examples of the blue visible light absorber having a maximum absorption wavelength at 380 to 500 nanometers in the present invention include the following yellow colorants and orange colorants.
Examples of yellow colorants and orange colorants include the following. The following types of coloring materials such as dyes and pigments are C.I. I. (Color index) Describe by number.
Examples of yellow pigments include C.I. I. Pigment Yellow 1, 3, 4, 5, 6, 12, 13, 14, 16, 17, 18, 20, 24, 55, 65, 73, 74, 81, 83, 86, 87, 93, 94, 95, 97, 98, 100, 101, 108, 109, 110, 113, 116, 117, 120, 123, 125, 128, 129, 133, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 156, 166, 168, 169, 170, 171, 172, 173, 175, and the like.
Examples of orange pigments include C.I. I. Pigment Orange 1, 2, 5, 13, 15, 16, 17, 18, 19, 31, 34, 36, 38, 40, 42, 43, 51, 52, 55, 59, 60, 61, 62, etc. .

Examples of the dye include azo dyes, quinoline dyes, nitro dyes, carbonyl dyes, and methine dyes.
Examples of the azo dye include C.I. I. Acid Yellow 11, C.I. I. Acid Orange 7, C.I. I. Direct Yellow 12, C.I. I. Direct Orange 26, C.I. I. Reactive Yellow 2, C.I. I. Disperse Orange 5, C.I. I. Moldant Yellow 5, C.I. I. Solvent yellow 16 etc. are mentioned.

Examples of quinoline dyes include C.I. I. Solvent Yellow 33, C.I. I. Acid Yellow 3, C.I. I. Disperse Yellow 64 and the like. Examples of nitro dyes include C.I. I. Acid Yellow 1, C.I. I. Acid Orange 3, C.I. I. Disperse Yellow 42 and the like. Examples of methine dyes include C.I. I. Disperse Yellow 201 etc. are mentioned.
Further, cobalt complex dyes and the like can be mentioned, and examples of cobalt complex dyes include C.I. I. Solvent yellow 89 etc. are mentioned.

  Specifically, examples of the azo dye include a monoazo dye of the following chemical formula 1. As such a monoazo dye of Chemical Formula 1, trade name: Oil Yellow 5001 manufactured by Orient Chemical Industry Co., Ltd. can be mentioned.

  Examples of methine dyes include methine dyes of the following chemical formulas 2 and 3. Examples of such methine dyes represented by Chemical formula 2 include Arimoto Chemical Co., Ltd. trade names: Plast Yellow DY-352 and Plast Yellow 8070. Moreover, as such a methine dye of Chemical Formula 3, there can be mentioned the product name: Oil Yellow 8000 manufactured by Orient Chemical Industries.

  The blue visible light absorber is preferably contained in an amount of 0.001 to 0.05 parts by mass with respect to 100 parts by mass of the adhesive resin for the reason of maintaining the total light transmittance. A blue visible light absorber content of less than 0.001 part by mass is not preferred because it tends to have a problem of insufficient cut performance of 380 to 500 nanometer light, and if it exceeds 0.05 part by mass, the total light transmittance decreases. However, it is not preferable because the image tends to have a problem that it looks dark.

  As the adhesive resin, any resin that exhibits adhesiveness (tackiness) at room temperature can be used. Examples of the adhesive resin include natural rubber; synthetic rubber such as styrene-butadiene, polyisobutylene, and isoprene; acrylic resin, for example, polymer of 2-ethylhexyl acrylate, butyl acrylate, and ethyl acrylate; olefin resin, for example , Polystyrene-ethylene / butylene copolymer, polyethylene, polystyrene-ethylene-propylene copolymer; silicone resin, for example, vinylpolydimethylsiloxane copolymer, vinyltrichlorosilane-alkoxysilane copolymer; urethane resin, for example , Obtained by reaction of polyisocyanate with the following polyols: polyester polyol, polyester polyol / polylactone polyol, polyester resin, saturated polyester, unsaturated polyester, etc. Can be mentioned.

An acrylic resin is particularly preferable. The acrylic resin can easily obtain a high total light transmittance, and can provide preferable adhesiveness. The acrylic resin preferably contains the following acrylic polymer.
It is preferable that the acrylic polymer contains at least an alkyl (meth) acrylate monomer, and a functional group-containing polymer (from a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an amino group-containing monomer, an amide group-containing monomer, and an epoxy group-containing monomer). More preferably, it is obtained by polymerizing at least one selected from the above and the alkyl (meth) acrylate monomer. Among these polymers, an acrylic polymer obtained by polymerization containing an alkyl (meth) acrylate {(meth) acrylic acid alkyl ester} monomer having 4 to 12 carbon atoms and a hydroxyl group-containing monomer is used. Is preferred. The acrylic polymer is preferably contained in an amount of 50 parts by mass or more with respect to 100 parts by mass of the pressure-sensitive adhesive resin solid component, and more preferably in the range of 60 to 99.9 parts by mass.

  Although it does not restrict | limit especially as alkyl (meth) acrylate (alkyl acrylate, alkyl methacrylate), For example, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl ( (Meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl ( Examples include meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, and dodecyl (meth) acrylate. In addition, the alkyl (meth) acrylate as a monomer component can be used individually or in combination of 2 or more types. Of these acrylates, n-butyl (meth) acrylate alone is particularly suitable. Although content of alkyl (meth) acrylate should just be 1-100 mass% in 100 mass parts of acrylic polymers, 50-99 mass% is suitable, and 70-98 mass% is still more suitable.

  Although it does not specifically limit as a carboxyl group-containing monomer, For example, (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. are mentioned. In addition, anhydrides of these carboxyl group-containing monomers can also be used as the carboxyl group-containing monomer.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, and acrylic. 4-hydroxybutyl acid, 4-hydroxybutyl methacrylate, 2-hydroxy-3-chloropropyl acrylate, 2-hydroxy-3-chloropropyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-methacrylic acid 2- And hydroxy-3-phenoxypropyl.

  Examples of the amino group-containing monomer include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, and the like.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide and the like.

  Examples of the epoxy group-containing monomer include glycidyl acrylate, glycidyl methacrylate, acrylate-2-ethyl glycidyl ether, and methacrylic acid-2-glycidyl ether.

  The carboxyl group-containing monomer, the hydroxyl group-containing monomer, the amino group-containing monomer, the amide group-containing monomer, and the epoxy group-containing monomer act as a crosslinking point with the crosslinking agent. The monomer containing these functional groups is used in a proportion of 0.1 to 15% by mass.

  The acrylic polymer can be produced by a known polymerization method, and examples thereof include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by ultraviolet irradiation. In addition, known polymerization initiators, chain transfer agents, and the like used in the polymerization can be appropriately used.

  The weight average molecular weight of the acrylic polymer is preferably 100,000 to 2,000,000, more preferably 300,000 to 1,500,000, and even more preferably 400,000 to 1,200,000.

  The acrylic polymer preferably has a glass transition temperature of less than 0 ° C., and is preferably less than −20 ° C. because the adhesiveness is further improved. The glass transition temperature is a shoulder value measured by a differential scanning calorimeter (DSC).

  The adhesive resin preferably contains a cross-linking agent. Examples of the crosslinking agent include an epoxy crosslinking agent, an isocyanate crosslinking agent, an imine crosslinking agent, and a peroxide crosslinking agent. Among these, an epoxy-based crosslinking agent and an isocyanate-based crosslinking agent are preferable.

  The epoxy-based crosslinking agent contains an epoxy compound, and examples of the epoxy compound include glycerin diglycidyl ether. The amount of the epoxy crosslinking agent used is 0.001 to 2 parts by mass, preferably 0.01 to 1 part by mass, and more preferably 0.02 to 0.5 parts by mass with respect to 100 parts by mass of the acrylic polymer. is there. When the amount of the epoxy compound used is less than 0.001 part by mass, it is not preferable in terms of adhesion and durability.

  The isocyanate-based crosslinking agent contains an isocyanate compound. Examples of the isocyanate compound include tolylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, water. Added isocyanate monomers such as diphenylmethane diisocyanate, adduct isocyanate compounds obtained by adding these isocyanate monomers with polyhydric alcohols such as trimethylolpropane, isocyanurate compounds, burette type compounds, and further known polyether polyols, polyester polyols, acrylics Polyol, polybutadiene polyol, polyisoprene polyol, etc. Such an addition-reacted urethane prepolymer type isocyanate. Among these isocyanate compounds, adduct isocyanate compounds such as xylylene diisocyanate are preferable from the viewpoint of improving the adhesion to the translucent substrate.

  The amount of the isocyanate crosslinking agent used is 0.001 to 5 parts by mass, preferably 0.01 to 3 parts by mass, and more preferably 0.02 to 2.5 parts by mass with respect to 100 parts by mass of the acrylic polymer. is there. When the amount of the isocyanate compound used is less than 0.001 part by mass, it is not preferable in terms of adhesion and durability.

  Various other known additives can be added to the pressure-sensitive adhesive of the present invention, but a tackifier, plasticizer, glass fiber, glass beads, metal powder, fillers made of other inorganic powders, Pigments, colorants, fillers, antioxidants, rust inhibitors, ultraviolet absorbers and the like can also be used.

An optical film can be obtained by laminating the above-mentioned pressure-sensitive adhesive on a translucent substrate. The translucent substrate and the adhesive may be laminated adjacent to each other, or another layer may be provided between the translucent substrate and the adhesive, or another layer may be provided on the adhesive. You may do it. Moreover, you may laminate | stack a translucent base | substrate on both surfaces of an adhesive.
Examples of the other layers include a hard coat layer, a polarizing layer, a light diffusion layer, a low reflection layer, an antifouling layer, an antistatic layer, an ultraviolet / near infrared (NIR) absorption layer, and an electromagnetic wave shielding layer. Can do.

  As a method of laminating the pressure-sensitive adhesive on the translucent substrate, a normal coating method or printing method is applied. Specifically, air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calendar coating, dam coating, dip coating Coating such as die coating, intaglio printing such as gravure printing, printing such as stencil printing such as screen printing, and the like can be used.

  The translucent substrate is not particularly limited as long as it is translucent, and glass such as quartz glass and soda glass can also be used. Polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyethylene naphthalate ( PEN), polymethyl methacrylate (PMMA), polycarbonate (PC), polyimide (PI), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), cycloolefin copolymer (COC), Various resin films such as norbornene-containing resin, acrylic resin, polyethersulfone, cellophane, and aromatic polyamide can be suitably used. A release layer can also be provided on the surface (one side or both sides) of these various resin films.

  The higher the transparency of these translucent substrates, the better. However, the total light transmittance (JIS K7105) is 80% or more, more preferably 90% or more. Further, the thickness of the translucent substrate is preferably thin from the viewpoint of weight reduction, but considering the productivity and handling properties, the thickness of the translucent substrate is in the range of 1 to 700 μm, preferably 25 to 250 μm. Is preferred.

  It is also possible to apply treatments such as alkali treatment, corona treatment, plasma treatment and sputtering treatment, primer coating such as surfactant and silane coupling agent, and thin film dry coating such as Si deposition on the surface of the translucent substrate. is there.

  Hereinafter, the present invention will be described based on examples.

(Preparation of acrylic adhesive resin)
As monomers, butyl acrylate (427.3 g), ethyl acrylate (171.2 g), 4-hydroxybutyl (meth) acrylate (1.5 g) were weighed and mixed thoroughly to obtain a polymerizable monomer mixture (a1). . Next, 300 g of this polymerizable monomer mixture (a1) and 160 g of ethyl acetate were placed in a flask. Also, add 300 g of the polymerizable monomer mixture (a1), 16 g of ethyl acetate and 0.15 g of 2,2′-azobis (4-methoxy-2,4-dimethyl) valeronitrile in the dropping funnel and mix well. A dropping mixture (a2) was prepared.

  Next, while flowing nitrogen gas at a rate of 20 ml / min, the internal temperature of the flask was raised to 95 ° C., and 2,2′-azobis (4-methoxy-2,4-dimethyl) valeronitrile as a polymerization initiator. (0.15 g) was charged into the flask to initiate the polymerization reaction. And the mixture (a2) for dripping was dripped at this flask over 90 minutes from the dropping funnel. After completion of the dropwise addition of the mixture for dropping (a2), the mixture was aged for 6 hours while being diluted with ethyl acetate as the viscosity increased. After completion of the reaction, an acrylic pressure-sensitive adhesive having a weight average molecular weight of 600,000 and an acid value of 0 mgKOH / g was obtained.

[Example 1]
A blue visible light absorber (CI Solvent Yellow 33, product name: Oil Yellow 5001, manufactured by Orient Chemical Industries, Ltd., maximum absorption wavelength: about 395 nanometers) is dissolved in methyl ethyl ketone (hereinafter referred to as MEK) to obtain a solid content. A 1% dye solution was prepared. On the other hand, an isocyanate curing agent Coronate L (manufactured by Nippon Polyurethane Industry) was separately dissolved in MEK as a crosslinking agent to prepare a crosslinking agent solution having a solid content of 10%. Then, the pressure-sensitive adhesive of the present invention was prepared by adding and mixing the pigment solution in an amount of 0.015 parts by weight and the cross-linking agent solution in 0.9 parts by weight in 100 parts by weight of the acrylic pressure-sensitive adhesive. Got.

  The pressure-sensitive adhesive prepared as described above was applied to release PET (product name: PET38C, manufactured by Lintec) with an applicator. The thickness at the time of coating was adjusted so that the thickness of the adhesive after drying was 25 μm. Subsequently, it was dried in an oven at 80 ° C. for 2 minutes. A release film (manufactured by Lintec, trade name: PET3801) was bonded to the layer made of this pressure-sensitive adhesive, and cured at room temperature for 7 days to produce the optical film of Example 1.

[Example 2]
In Example 1, as the blue visible light absorber, a blue visible light absorber (CI Disperse Yellow 201, trade name manufactured by Arimoto Chemical Industry: Last Yellow DY-352, maximum absorption wavelength: about 440) The pressure-sensitive adhesive and optical film of the present invention were obtained in the same manner except that the nanometer was replaced.

[Example 3]
In Example 1, as the blue visible light absorber, a blue visible light absorber (CI Solvent Yellow 89, trade name: Orasol Yellow 2RLN, manufactured by Ciba Japan Co., Ltd., maximum absorption wavelength: about 470 nanometers) A pressure-sensitive adhesive and an optical film of the present invention were obtained in the same manner except that they were replaced.

[Evaluation]
The light release side release PET was peeled off from the optical films of Examples 1 to 3 obtained above and bonded to easy-adhesion-treated optical PET (trade name: Cosmo Shine A4300, manufactured by Toyobo Co., Ltd.). Furthermore, the heavy release side release PET was peeled off from each optical film to obtain an adhesive optical film for evaluation test. The transmission spectrum was measured with a spectrophotometer (manufactured by Shimadzu Corporation, trade name: UV3150) for each of the obtained optical films for evaluation tests.
The transmission spectra of each optical film are shown in FIGS.
As is clear from FIGS. 1 to 3, the optical films of Examples 1 to 3 have a maximum value with low transmittance between wavelengths of 380 to 500 nanometers, and are confirmed to cut blue visible light. It was done.
Therefore, the pressure-sensitive adhesive of the present invention is a pressure-sensitive adhesive that cuts blue visible light and has excellent durability. Moreover, the optical film of this invention can be easily affixed on arbitrary positions with respect to blue visible light radiation | emission objects, such as LED light sources, such as a lighting fixture, using this adhesive.

Claims (3)

It contains an adhesive resin and a blue visible light absorber having a maximum absorption wavelength at 380 to 500 nanometers, and the blue visible light absorber is 0.001 to 0.05 mass with respect to 100 mass parts of the adhesive resin. A pressure-sensitive adhesive characterized by not containing a near-infrared absorber and a dye having a maximum absorption at a wavelength of 570 to 610 nm . An optical film comprising the pressure-sensitive adhesive according to claim 1 laminated on a translucent substrate. The optical film according to claim 2, wherein the optical film is used in a lighting device using a light emitting diode .

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