JP5573405B2 - Photosensitive resin composition, photosensitive resin varnish, photosensitive resin film, photosensitive resin cured product, and visible light guide - Google Patents

Description

  The present invention relates to a photosensitive resin composition, a photosensitive resin varnish, a photosensitive resin film, a cured product thereof, and a visible light guide path made of the cured product. More specifically, the photosensitivity has excellent transparency in the visible light wavelength region, little deterioration such as coloring in the high-temperature and high-humidity reliability test, and further improved the refractive index to improve light transmittance. The present invention relates to a resin composition, a photosensitive resin varnish, a photosensitive resin film, and cured products thereof. In addition, the cured product in the present invention is applied to a visible light guide path.

  An LED is an example of an illumination light source that has been widely used in recent years. Since LEDs have the characteristics of high brightness and low power consumption, they are widely used in various mobile devices such as mobile phones, personal digital assistants (PDAs), portable game devices, and portable audio devices. In addition, in recent years, applications for large-sized devices such as backlights for liquid crystal displays have been developed.

  Since such a device is required to further reduce power consumption, weight, and thickness, it is desired to use a more efficient lighting device. Under such a background, attention has been focused on a light guide, a light guide plate, and an illumination device using the waveguide.

  Among them, a device using a polymer is excellent in processability and can have a flexible structure. Therefore, a polymer light guide, a polymer light guide plate, and a polymer waveguide are considered to be optimal for these applications.

  The polymer material used for the lighting device is required to have high transparency in the visible light wavelength region of 380 to 780 nm from the viewpoint of the usage environment of the applied equipment. Conventionally, vinyl copolymers represented by alicyclic polyolefins, (meth) acrylic polymers, and the like have been used as polymer materials that satisfy these required characteristics. Many of these polymer materials are utilized mainly for prisms, lenses, light guide plates, etc., taking advantage of their high transparency. However, since the molding method is centered on melt molding such as injection molding or extrusion molding, it is difficult to process a small and complicated member or an extremely thin member. Further, since these polymer materials are thermoplastic resins, they have a problem of poor heat resistance reliability and moisture resistance reliability.

  As a processing technique capable of forming a complicated member, a casting method, an imprint method, a stamp method, a transfer method, and the like can be considered. Further, when a coating method, a printing method, a spin coater method or the like is used, a thin member can be formed. By injecting a liquid with photosensitivity into a mold of any shape, or by pressing the liquid into a casting mold with a mold, or pressing a material processed into a film or sheet with a mold and irradiating with light Three-dimensional cross-linking and insolubilization can easily form a complex-shaped member. Therefore, materials having photosensitivity and excellent optical characteristics, in particular, transparency in the visible light region have been studied (for example, see Patent Documents 1 and 2).

JP-A-6-128342 JP 2001-288206 A

In order to ensure the transparency of visible light with the above-described conventional materials, the amount of photoinitiator added was increased in order to advance curing, and the occurrence of bleedout of unreacted polymerizable compounds was suppressed. . However, the remaining unreacted photoinitiator and its decomposition products cause thermal degradation, resulting in poor high temperature and high humidity reliability.
Further, when transmitting light, it is important that the refractive index of the light transmitting portion is higher than that of the surrounding area. If the refractive index of the light transmission part is equal to or lower than that of the periphery, light leaks to the periphery. In addition, if even a part of the light transmitting part is in contact with a part having the same or higher refractive index, light leaks from the light transmitting part and the light transmittance is lowered. From the above, a material having a high refractive index is demanded as a material for the light transmitting portion.

  The present invention has been made to solve the above problems, and has high transparency in the visible light wavelength region of 380 to 780 nm, excellent high-temperature and high-humidity reliability, and further improves the refractive index in order to improve light transmittance. Another object of the present invention is to provide a photosensitive resin composition, a photosensitive resin varnish, a photosensitive resin film, a cured product thereof, and a visible light guide path made of the cured product.

The present inventors have found that the following (1) to (5) solve the above problems.
(1) A photosensitive resin composition comprising (A) an acrylic polymer, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a hindered phenol-based antioxidant, wherein (A) With respect to the total amount of the component and the component (B), the content of the component (A) is 30 to 70% by mass, the content of the component (B) is 30 to 70% by mass, the component (A) and the component (B) The content of component (C) is 0.03 to 3.0 parts by mass, and the content of component (D) is 0.01 to 1.0 parts by mass with respect to 100 parts by mass of the total amount of components, B) The polymerizable compound contains an aromatic polymerizable compound, and the content thereof is 10 to 40% by mass based on the total amount of the component (A) and the component (B). Resin composition.
(2) A photosensitive resin varnish containing the photosensitive resin composition of (1) above and an organic solvent.
(3) A photosensitive resin film obtained by applying the photosensitive resin varnish of (2) above onto a substrate film and drying it.
(4) A cured photosensitive resin obtained by irradiating and curing the photosensitive resin composition of (1), the photosensitive resin varnish of (2), or the photosensitive resin film of (3).
(5) A visible light guide path comprising the cured photosensitive resin of (4).

  According to the present invention, a photosensitive resin composition having high transparency in the visible light wavelength region, and high temperature and high humidity reliability, and further improving the refractive index in order to improve light transmittance, a photosensitive resin varnish, It is possible to provide a photosensitive resin film, a cured photosensitive resin obtained by photocuring these, and a visible light guide.

It is the top view (upper) and front view (lower) of the apparatus which measures white LED transmitted light intensity ratio.

  The photosensitive resin composition of the present invention comprises (A) an acrylic polymer, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a hindered phenol-based antioxidant. It is a thing.

  In the present invention, the content of the component (A) is 30 to 70 mass%, the content of the component (B) is 30 to 70 mass% with respect to the total amount of the component (A) and the component (B), The content of component (C) is 0.03 to 3.0 parts by mass, and the content of component (D) is 0.01 to 1 with respect to 100 parts by mass of the total amount of component (A) and component (B). 0.0 parts by mass, and the polymerizable compound (B) contains an aromatic polymerizable compound, and the content thereof is 10 to 40% by mass based on the total amount of the component (A) and the component (B). It is characterized by being.

[(A) Acrylic polymer]
(A) Content of an acrylic polymer is the range of 30-70 mass% with respect to the total amount of (A) component and (B) component. When the content of the component (A) is less than 30% by mass, it is difficult to process the photosensitive resin composition into a film, which is not preferable. Moreover, when content of (A) component exceeds 70 mass%, since the reliability in a high temperature, high humidity test falls, it is unpreferable. The content of the component (A) is preferably in the range of 40 to 60% by mass, more preferably 45 to 55, from the viewpoint of the processability of the photosensitive resin composition to the film and the maintenance of high temperature and high humidity reliability. It is the range of mass%.

The (A) acrylic polymer of the photosensitive resin composition of the present invention may be either a homopolymer composed of a single monomer or a copolymer composed of two or more monomers.
Among them, the (A) acrylic polymer is preferably a polymer obtained by polymerizing at least one selected from the group consisting of methyl methacrylate, butyl methacrylate, butyl acrylate, 2-hydroxyethyl acrylate, and methacrylic acid as a monomer. That is, a homopolymer of the above monomers or two or more monomer copolymers selected from the above monomers are preferable.
In particular, methyl methacrylate contributes to the high transparency of the acrylic polymer. Butyl methacrylate and butyl acrylate contribute to giving the acrylic polymer any glass transition temperature. 2-Hydroxyethyl acrylate and methacrylic acid contribute to improving the compatibility between the acrylic polymer and the component (B) described later. From the above viewpoint, a specific (A) acrylic polymer is obtained using various monomers as necessary, and by using this, high transparency in the visible light wavelength region, an arbitrary glass transition temperature, ( It is possible to provide a photosensitive resin composition satisfying all the compatibility with the component B).

(A) It is preferable that the weight average molecular weight of an acrylic polymer exists in the range of 30,000-300,000. When the weight average molecular weight of the component (A) is 30,000 or more, it is preferable because it can be easily processed into a film and a cured photosensitive resin having sufficient strength and flexibility can be obtained. In the high temperature and high humidity test, the occurrence of bleeding out of the component (A) can be suppressed and the reliability can be maintained. On the other hand, if the weight average molecular weight is 300,000 or less, an appropriate viscosity of the photosensitive resin composition and the photosensitive resin composition varnish can be obtained, so that the processability to a film is excellent, and the obtained cured product is excellent. It is preferable because of its flexibility. Moreover, since it has the outstanding compatibility with the (B) component mentioned later, the haze of the photosensitive resin cured | curing material can be suppressed as a result, and high transparency can be obtained, it is preferable. Therefore, from the above viewpoint, the weight average molecular weight of the component (A) is more preferably in the range of 40,000 to 150,000, and particularly preferably in the range of 60,000 to 120,000.
The weight average molecular weight in the present invention is a value measured by gel permeation chromatography (GPC) and converted to standard polystyrene.

  (A) It is preferable that the glass transition point of an acrylic polymer is the range of 30-100 degreeC. If the glass transition point of (A) component is 30 degreeC or more, since the hardness of the photosensitive resin hardened | cured material obtained is enough and the hardened | cured material can hold | maintain the shape in a high temperature, high humidity reliability test, it is preferable. On the other hand, if the glass transition point is 100 ° C. or less, the cured photosensitive resin is preferable because it has excellent flexibility. Therefore, from the viewpoint of the strength of the obtained photosensitive resin cured product, the glass transition point of the (A) acrylic polymer is more preferably in the range of 45 to 85 ° C, particularly preferably in the range of 55 to 75 ° C. .

  The (A) acrylic polymer is not limited in the structure of the polymer, the polymerization method, and the kind of the polymerization reaction as long as it falls within the range of the above-mentioned preferred weight average molecular weight and glass transition point. For example, solution polymerization method, suspension polymerization method, emulsion polymerization method, bulk polymerization method, gas phase polymerization method, etc. are used as the polymerization method, and radical polymerization, cationic polymerization, anionic polymerization, coordination polymerization, etc. are used as the polymerization reaction. it can.

[(B) Polymerizable compound]
(B) Content of a polymeric compound is the range of 30-70 mass% with respect to the total amount of (A) component and (B) component. When the content of the component (B) is less than 30% by mass, the cured product obtained by photocuring the photosensitive resin composition has a low crosslinking density, and the curing reaction is difficult to proceed. Since out is likely to occur, the reliability in the high-temperature and high-humidity test decreases, which is not preferable. Moreover, to advance the curing reaction, it can be solved by increasing the amount of (C) photopolymerization initiator added, but in this method, thermal degradation occurs due to the remaining unreacted (C) photopolymerization initiator and its decomposition products. The high temperature and high humidity reliability is inferior. On the other hand, when the content of the component (B) exceeds 70% by mass, it is difficult to process the photosensitive resin composition into a film, which is not preferable. From the viewpoint of the processability of the photosensitive resin composition into a film, the curability of the photosensitive resin composition, and the maintenance of high temperature and high humidity reliability, the content of the component (B) is preferably 40 to 60% by mass. More preferably, it is the range of 45-55 mass%.

(B) The polymerizable compound has at least one polymerizable group in one molecule that can be chain-polymerized by radicals emitted when light is irradiated on the photopolymerization initiator, and has a visible light wavelength region of 380 to 780 nm. Those having no light absorption within the range of are preferred. Specific examples of the polymerizable compound (B) include those described in International Publication WO2009 / 066668. Among them, a compound having an unsaturated double bond group such as a (meth) acryloyl group, a vinyl group or an allyl group is particularly preferable from the viewpoint of having an appropriate polymerization rate due to radicals.
As the properties, any of solid, semi-solid and liquid can be used.

  In addition, as the polymerizable compound (B), any of monofunctional and bifunctional or higher polyfunctional compounds can be used, and particularly includes at least one selected from bifunctional or higher polyfunctional polymerizable compounds. It is preferable. By using a polyfunctional polymerizable compound, three-dimensional crosslinking proceeds, and a cured product having little shape change with respect to heat can be obtained. In addition, the monofunctional polymerizable compound is appropriately mixed as necessary in order to reduce the viscosity of the photosensitive resin composition and facilitate handling. These compounds can be used alone or in combination of two or more, and can also be used in combination with other polymerizable compounds.

In the photosensitive resin composition of this invention, (B) polymeric compound contains the polymeric compound which has aromatic, The content is 10-40 with respect to the total amount of (A) component and (B) component. % By mass.
When the content is less than 10% by mass, the increase in refractive index is small and the light transmittance cannot be sufficiently improved. On the other hand, if it exceeds 40% by mass, the refractive index increases, but the transparency is lowered, which is not preferable. As content of the polymeric compound which has an aromatic, from a viewpoint of maintaining high transparency, improving a refractive index, it is the range of 15-35 mass% with respect to the total amount of (A) component and (B) component. Is more preferable, and the range of 20-30 mass% is still more preferable.

  The polymerizable compound having an aromatic in the component (B) is preferably a polymerizable compound having a bisphenol A skeleton. The polymerizable compound having a bisphenol A skeleton is less likely to be deteriorated by heat or light, and can be easily produced because there are many types of derivatives. Furthermore, among the polymer compounds having a bisphenol A skeleton, the polymerizable compound represented by the following general formula (1) changes the chain length of ethylene oxide, so that the compatibility and the refractive index can be easily adjusted. Particularly preferred.

In the general formula (1), X ¹ and X ² are each a hydrogen atom or a methyl group, m and n are positive integers, and m + n is in the range of 2 to 14.

  The polymerizable compound represented by the general formula (1) used in the present invention can be obtained by a general synthesis method. For example, “FA-321A” (EO-modified diacrylate; average EO chain length) = 10, manufactured by Hitachi Chemical Co., Ltd.), "FA-324A" (EO-modified diacrylate; average EO chain length = 4, manufactured by Hitachi Chemical Co., Ltd.), "FA-321M" (EO-modified dimethacrylate; Commercially available compounds such as average EO chain length = 10, manufactured by Hitachi Chemical Co., Ltd. can also be used.

  As the polymerizable compound having an aromatic component in component (B), specifically, a compound having a phenyl, bisphenol F, bisphenol S, biphenyl, naphthyl, fluorenyl group or the like in addition to a compound having a bisphenol A skeleton is used. Can do. Among them, bisphenol F, a fluorenyl group, and the like having a small conjugation elongation are preferable because they have low short wavelength absorption and high transparency.

  (B) As a polymeric compound which has an aromatic in a component, the bifunctional (meth) acrylate shown by following General formula (2) is mentioned as a compound which has a (meth) acryloyl group, for example.

In the general formula (2), R ₁ and R ₂ are each a hydrogen atom or a methyl group. R ₃ is represented by the following general formula (3).

In the general formula (3), a + b is in the range of 2 to 30, R ₄ and R ₅ are each hydrogen atom or a methyl group. R ₆ is any one of divalent groups represented by the following general formula (4).

  The polymerizable compound having an aromatic in the component (B) can be used alone or in combination of two or more kinds, and can also be used in combination with other polymerizable compounds.

  Specific examples of the polymerizable compound having no aromatic component in component (B) include (meth) acrylate, vinylidene halide, vinyl ether, vinyl ester, vinyl pyridine, vinyl amide, arylated vinyl, and the like. Of these, (meth) acrylate and arylated vinyl are preferable from the viewpoint of transparency. As the (meth) acrylate, either a monofunctional one or a bifunctional or higher polyfunctional one can be used.

  (B) As a polymeric compound which does not have an aromatic in a component, the bifunctional (meth) acrylate shown by following General formula (5) is mentioned as a compound which has a (meth) acryloyl group, for example.

In the general formula (5), R ₇ and R ₈ are each a hydrogen atom or a methyl group. R ₉ is represented by the following general formula (6), (7) or (8).

In the general formulas (6), (7), and (8), R _{10 to} R ₁₅ are each a hydrogen atom or a methyl group. C is in the range of 1-30. d and e are average values, each ranging from 1 to 15. Moreover, f, g, and h are each an average value, and are the range of 1-10.

  The polymerizable compound having no aromatic in the above component (B) can be used alone or in combination of two or more, after containing a predetermined amount of the above-mentioned polymerizable compound having an aromatic, It can also be used in combination with other polymerizable compounds.

[(C) Photopolymerization initiator]
(D) Content of a photoinitiator is the range of 0.03-3.0 mass part with respect to 100 mass parts of total amounts of (A) component and (B) component. When the content of the component (C) is less than 0.03 parts by mass, the curing reaction does not proceed sufficiently by irradiation with light, which is not preferable. If the amount exceeds 3.0 parts by mass, the effect of coloring derived from the component (C) increases, and as a result, the transparency in the visible light wavelength region decreases, which is not preferable. From the viewpoint of photocurability of the photosensitive resin composition and transparency in the visible light wavelength region, the content of the component (C) is preferably based on 100 parts by mass of the total amount of the component (A) and the component (B). It is 0.1-1.5 mass parts, More preferably, it is 0.1-1.0 mass part.

  (C) At least one selected from (C-1) α-hydroxyacetophenone photoinitiators and glyoxyester photoinitiators as photopolymerization initiators, and (C-2) phosphine oxide photoinitiators It is preferable to contain. By using such a specific (C) photopolymerization initiator, a cured product having little coloration and high transparency in the visible light wavelength region can be obtained.

Examples of the α-hydroxyacetophenone photoinitiator as component (C-1) include 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- ( 2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- (4- (4- (2-hydroxy-3,5,2-methylpropionyl) ) -Benzyl) -phenyl) -2-methylpropan-1-one, and the like.
Examples of the glyoxyester photoinitiator include oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester, and mixtures thereof. Can be mentioned. Among these, oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid 2- (2-hydroxyethoxy) are less colored and highly transparent in the visible light wavelength region. ) Ethyl esters and mixtures thereof are particularly preferred.

  Examples of the phosphine oxide photoinitiator as component (C-2) include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine oxide, and mixtures thereof. Etc. When such a photoinitiator is used, not only curing is possible with a small amount of light irradiation but also photobleaching ability, and thus the obtained photocured product has excellent transparency in the visible light region. Among these, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is preferable because it has excellent transparency particularly in the visible light region and has high curability.

[(D) hindered phenolic antioxidant]
(D) Content of hindered phenolic antioxidant is the range of 0.01-1.0 mass part with respect to 100 mass parts of total amounts of (A) component and (B) component. If the content of (D) is less than 0.01 parts by mass, the high temperature and high humidity reliability is inferior, which is not preferable. Moreover, since it will superpose | polymerize in the case of photocuring when it exceeds 1.0 mass part, it is unpreferable. From the viewpoint of the curability of the photosensitive resin composition and the high temperature and high humidity reliability, the content of the component (D) is preferably 0.1 with respect to 100 parts by mass of the total amount of the component (A) and the component (B). It is -1.0 mass part, More preferably, it is 0.2-1.0 mass part.

  (D) As a hindered phenol-based antioxidant, a hindered phenol-based agent which must have at least one phenol group in a molecule having one methyl group and one t-butyl group on the same aromatic ring. It is especially preferable that it is antioxidant and is shown by following formula (9). When these compounds are used, the heat resistance reliability can be improved, and since the polymerization inhibition during photocuring is small, the curability is good. Further, productivity is high because the amount of light irradiation required for curing is small.

  X in the above formula (9) is one of the divalent groups of the following formulas (10) and (11).

[Other additives]
In addition to the above components (A) to (D), the photosensitive resin composition of the present invention includes, as necessary, a yellowing inhibitor, an ultraviolet absorber, a visible light absorber, a leveling agent, a colorant, a plasticizer. You may add what is called additives, such as an agent, a stabilizer, a filler, and a fluorescent whitening agent, in the ratio which does not have a bad influence on the effect of this invention.

  Moreover, the photosensitive resin composition of this invention can be diluted with a suitable organic solvent, and can be used as a photosensitive resin varnish. The organic solvent used here is not particularly limited as long as it can dissolve the resin composition. For example, aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, p-cymene; tetrahydrofuran, 1, 4 -Cyclic ethers such as dioxane; alcohols such as methanol, ethanol, isopropanol, butanol, ethylene glycol, propylene glycol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone; acetic acid Esters such as methyl, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; ethylene glycol monomethyl ether, ethylene glycol mono Chill ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol Polyhydric alcohol alkyl ethers such as dimethyl ether and diethylene glycol diethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene group Polyhydric alcohol alkyl ether acetates such as recall monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate; N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, etc. And amides.

Among these, from the viewpoint of solubility and boiling point, methanol, ethanol, isopropanol, acetone, toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, ethylene glycol monomethyl ether , Ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and N, N-dimethylacetamide.
These organic solvents can be used alone or in combination of two or more.
Moreover, it is preferable that the solid content density | concentration in a resin varnish is 20-80 mass% normally.

[Photosensitive resin varnish]
When preparing the photosensitive resin varnish, it is preferable to mix by stirring. Although there is no restriction | limiting in particular about the stirring method, The stirring using a propeller is preferable from a viewpoint of stirring efficiency. Although there is no restriction | limiting in particular in the rotational speed of the propeller at the time of stirring, It is preferable that it is 10-1,000min- ¹ . When it is 10 min ⁻¹ or more, each of the components (A) to (D) and the organic solvent is sufficiently mixed, and when it is 1,000 min ⁻¹ or less, there is less entrainment of bubbles due to propeller rotation. Therefore, it is preferable. More preferably 50～800Min ^-1 From the above viewpoint, it is particularly preferably 100~500min ^-1.

  Although there is no restriction | limiting in particular also about stirring time, It is preferable that it is 1 to 24 hours. If it is 1 hour or longer, each of the components (A) to (D) and the organic solvent is sufficiently mixed, and if it is 24 hours or shorter, the varnish preparation time can be shortened and sufficient. Since productivity is obtained, it is preferable.

  The prepared photosensitive resin varnish is preferably filtered using a filter having a pore diameter of 50 μm or less. It is preferable to use a filter having a pore size of 50 μm or less because large foreign matters and the like are removed, no repellency or the like occurs when applying the varnish, and scattering of light propagating through the core portion is suppressed. From the above viewpoint, it is more preferable to filter using a filter having a pore diameter of 30 μm or less, and it is particularly preferable to filter using a filter having a pore diameter of 10 μm or less.

  The prepared photosensitive resin varnish is preferably degassed under reduced pressure. There is no restriction | limiting in particular in the defoaming method, As a specific example, a degassing apparatus with a vacuum pump and a bell jar and a vacuum apparatus can be used. Although there is no restriction | limiting in particular in the pressure reduction degree at the time of pressure reduction, the range in which the organic solvent contained in a resin varnish does not boil is preferable. Although there is no restriction | limiting in particular in vacuum degassing time, It is preferable that it is 3 to 60 minutes. If it is 3 minutes or longer, it is preferable because bubbles dissolved in the resin varnish can be removed, and if it is 60 minutes or less, the organic solvent contained in the resin varnish does not volatilize.

[Photosensitive resin film]
Hereinafter, the photosensitive resin film of the present invention will be described.
The photosensitive resin film of this invention consists of the said photosensitive resin composition, apply | coats the photosensitive resin varnish containing said (A)-(D) component to a suitable base film, and uses methods, such as drying. Then, the solvent can be removed to form a photosensitive resin layer (hereinafter sometimes simply referred to as “resin layer”). Moreover, you may apply | coat and manufacture a photosensitive resin composition directly to a base film, without varnishing.

  The base film is not particularly limited, and examples thereof include: polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefins such as polyethylene, polypropylene, and polyethylene-vinyl acetate copolymer; polyvinyl chloride, polyvinylidene chloride, Examples include polycarbonate, polyamide, polyimide, polyamideimide, polyetherimide, polyethersulfide, polyethersulfone, polyetherketone, polyphenyleneether, polyphenylenesulfide, polyarylate, polysulfone, and liquid crystal polymer.

  Among these, from the viewpoint of flexibility and toughness, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene, polyethylene-vinyl acetate copolymer, polycarbonate, polyamide, polyimide, polyamideimide, polyphenylene ether, polyphenylene sulfide, Polyarylate and polysulfone are preferred.

  The thickness of the base film may be appropriately changed depending on the intended flexibility, but is preferably 3 to 250 μm. If it is 3 μm or more, sufficient film strength is obtained, and if it is 250 μm or less, sufficient flexibility is obtained. From the above points, the thickness of the base film is more preferably 5 to 200 μm, and further preferably 7 to 150 μm. In addition, in order to improve the peelability from the resin layer, a film that has been subjected to a release treatment with a silicone compound, a fluorine-containing compound, or the like may be used as necessary.

  A photosensitive resin film produced by applying a photosensitive resin varnish or a photosensitive resin composition on a base film is affixed with a protective film on the resin layer as necessary. Or it is good also as a 3 layer structure of the resin layer and protective film which consist of photosensitive resin hardened | cured material.

  The protective film is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyolefins such as polyethylene and polypropylene. Among these, from the viewpoint of flexibility and toughness, polyesters such as polyethylene terephthalate; polyolefins such as polyethylene and polypropylene are preferable. In addition, from the viewpoint of improving the peelability from the resin layer, a film that has been subjected to a release treatment with a silicone compound, a fluorine-containing compound, or the like may be used as necessary.

  The thickness of the protective film may be appropriately changed depending on the intended flexibility, but is preferably 10 to 250 μm. If it is 10 μm or more, sufficient film strength can be obtained, and if it is 250 μm or less, sufficient flexibility can be obtained. From the above points, the thickness of the protective film is more preferably 15 to 200 μm, and still more preferably 20 to 150 μm.

  Although there is no restriction | limiting in particular about the thickness of the resin layer of the photosensitive resin film of this invention, It is preferable that it is 5-500 micrometers normally by the thickness after drying. If it is 5 μm or more, it has the necessary thickness, so that the strength of the photosensitive resin film or the cured product of the film is sufficient, and if it is 500 μm or less, it can be sufficiently dried and the residual solvent in the resin film The amount decreases, and foaming or the like hardly occurs when the cured product of the film is heated.

  The photosensitive resin film thus obtained can be easily stored, for example, by winding it into a roll. Alternatively, a roll-shaped film can be cut into a suitable size and stored in a sheet shape.

[Hardened photosensitive resin]
The photosensitive resin composition of the present invention can be quickly photocured. Here thickness 0.5 mm, the reaction rate of the cured product obtained by the light irradiation amount 3000 mJ / cm ² as 100%, it is preferable 100 mJ / cm ² irradiation time of the reaction rate is 80% or more. When such a material is used, a material excellent in productivity of a molded product can be obtained.

The kind of light for curing used in the present invention is not particularly limited as long as the curing reaction proceeds, but from the viewpoint of fast curing, the light is preferably UV light, and (C ) From the viewpoint of the absorption wavelength of the photoinitiator, it is more preferable to cure with 365-nm i-rays in UV light. There are no particular limitations on the light source that emits 365-nm i-rays. Examples of light sources include mercury lamps such as low-pressure mercury lamps, high-pressure mercury lamps, and ultra-high-pressure mercury lamps, as well as tungsten lamps, xenon lamps, gas lasers, and semiconductor lasers. Etc. The dose necessary for curing may vary in thickness and refractive index of the cured product such as seeking, it is generally at an illuminance 1~1000mW / cm2, to obtain a cured product by irradiating 10 to 10000 mJ / cm ² Can do.

  About the obtained hardened | cured material, it is preferable that the refractive index of hardened | cured material is 1.49 or more, and it is more preferable that it is 1.495 or more. When the refractive index is 1.49 or more, the light transmittance can be sufficiently improved.

  The obtained cured product preferably has a light transmittance of 92% or more in a test piece having a thickness of 200 μm in a visible light region of 380 to 780 nm. When a cured product having a light transmittance of 92% or more is used, light can be propagated without reducing the illuminance of light and without changing the color of the light source.

  The obtained cured product preferably has a haze of 3% or less and more preferably 2.6 or less at a thickness of 200 μm. When the haze is 3% or less, a cured product having sufficient transparency can be obtained.

  Moreover, the photosensitive resin composition of this invention can obtain hardened | cured material by carrying out hardening reaction or polymerization reaction by light, a heat | fever, etc. In that case, it is also possible to obtain a cured product having an arbitrary shape by making it into an arbitrary shape such as a sheet, a film, a strip, etc. in advance and then performing a curing reaction or the like. The cured product thus obtained can be used as a visible light guide for an illumination device by being used in an air clad.

  Examples of the present invention will be described more specifically below, but the present invention is not limited to these examples.

[Example 1]
(1) Preparation of photosensitive resin composition In a brown plastic bottle with a capacity of 200 mL, (A) acrylic polymer, “Hitaroid HA-3204EB-1E” (weight average molecular weight: 86,000, hydroxyl value: 30 mgKOH / g, Acid value: 3.8 mgKOH / g, glass transition point: 70 ° C., resin content 37 mass%, ethyl acetate / butyl acetate mixed solution, manufactured by Hitachi Chemical Co., Ltd.) 111 g, (B) as polymerizable compound , “NK ester APG-400” (polypropylene glycol diacrylate; average PO chain length = 7, manufactured by Shin-Nakamura Chemical Co., Ltd.), 30.0 g, “Fancryl FA-321A” (bisphenol A skeleton, EO-modified di Acrylate; average EO chain length = 10, manufactured by Hitachi Chemical Co., Ltd.) 20.0 g, (C) As a photopolymerization initiator, “IRGACURE75 ”(Oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, mixture of oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester, manufactured by Ciba Specialty Chemicals Co., Ltd.), 0.1 g of “DAROCURE-TPO” (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, manufactured by Ciba Specialty Chemicals Co., Ltd.) and (D) “Adekastab AO-80” (as a phenolic antioxidant) 0.2 g of hindered phenol antioxidant (manufactured by ADEKA) and 10 g of acetone were blended and stirred at room temperature for 12 hours using a mix rotor. The obtained mixture was subjected to pressure filtration using a membrane filter having a pore size of 2 μm, and vacuum deaerated at 10 mmHg to prepare a photosensitive resin composition.

(2) Preparation of photosensitive resin film Coating the photosensitive resin composition prepared in (1) on the release-treated surface of a PET film (manufactured by Teijin DuPont Films, trade name: A53, thickness: 50 μm) (Product name: Multicoater TM-MC, manufactured by Hirano Techseed Co., Ltd.), dried at 100 ° C. for 20 minutes, and then a release PET film (manufactured by Teijin DuPont Films, trade name: A31, thickness) as a protective film 25 μm) was pasted to obtain a photosensitive resin composition film. At this time, the thickness of the resin layer can be arbitrarily adjusted by adjusting the gap of the coating machine, but in this example, the thickness after curing was adjusted to 200 μm.

(3) Creation of cured product Using the film obtained in (2), 2000 mJ / cm ² from above the release PET film using an ultraviolet exposure machine (Dainippon Screen Co., Ltd., trade name: MAP-1200-L). Irradiated with UV. Then, the base film and the protective film were peeled off to obtain a film-like photocured product. Thereafter, test pieces were cut into arbitrary shapes and used for various measurements.

(4) Evaluation of transmittance A sample obtained by cutting the cured product obtained in (3) into a size of 4 cm × 4 cm was used for evaluation. The transmittance was measured at a measurement wavelength of 200 to 800 nm using a spectrophotometer U-3310 manufactured by Hitachi, Ltd. From the measurement results, three points of 420 nm, 560 nm, and 780 nm were evaluated. When the obtained cured product was evaluated, the transmittance was 92% (420 nm), 92% (560 nm), and 92% (780 nm), and the transparency was good.

(5) Refractive index measurement About the sample which cut out the hardened | cured material obtained by (3) to 1 cm x 2 cm size, Atago Co., Ltd. Abbe refractometer T2 and measurement temperature 23 degreeC, wavelength 589nm (D line) When the refractive index was measured, the refractive index was 1.495.

(6) Haze measurement About the sample which cut out the hardened | cured material (thickness 200 micrometers) obtained by (3) in 2 cm x 2 cm size, it measured at 23 degreeC using Nippon Denshoku Industries Co., Ltd. product chromaticity meter 300A. When the haze was measured, the haze was 2.4% at a thickness of 200 μm.

(7) Measuring method of white LED transmission intensity It demonstrates using FIG. FIG. 1 is a plan view (upper) and a front view (lower) of an apparatus for measuring a white LED transmitted light intensity ratio. Sample 3 obtained by cutting the cured product obtained in (3) into 1 cm × 10 cm size was used for evaluation. A side-emitting white LED was used as the light source 2, and light was emitted at an input current of 15 mA. Sample 3 was placed on substrate 1, and white LED light (light source transmission intensity ratio = 4.2) was incident from the end face. Measure the spectrum of transmitted light using the multi-photometry system MCPD-3000 manufactured by Otsuka Electronics Co., Ltd., and the transmission intensity ratio from the peak intensity of the emitted light. Calculated according to

Transmission intensity ratio = (Int ₄₆₀ / Int ₅₆₀ )
(Int ₄₆₀ : Intensity of peak mainly caused by B band seen in the vicinity of ₄₆₀ nm Int ₅₆₀ : Intensity of peak mainly seen in the vicinity of ₅₆₀ nm due to mixed light of G band and R band.)
The transmission intensity ratio is preferably 2.0 or more, and more preferably 2.5 or more. Therefore, when the transmission intensity ratio is less than 1.5, ×, when 1.5 or more and less than 2.0, Δ, when 2.0 or more and less than 2.5, ○, when 2.5 or more, ◎ did.
When the obtained cured product was evaluated, the transmission intensity ratio was 3.1, and the transmitted light was white light similar to the white LED light source.

(8) High-temperature and high-humidity reliability test The test piece evaluated in (7) was put in an oven prepared at 85 ° C./85% RH. When the white LED transmission intensity was measured in the same manner as in (7) after 250 hours, the transmission intensity ratio was 2.0, and the transmitted light was white light similar to the white LED light source.

[Examples 2 to 4 and Comparative Examples 1 to 3]
According to the composition of Table 1 and Table 2, the same operation as Example 1 was performed, and after obtaining the photosensitive resin composition, the hardened | cured material was created similarly to Example 1, and evaluated. The results are shown in Tables 1 and 2.

(Explanation in Tables 1 and 2)
A-1: Acrylic acrylate copolymer (trade name: Hitaroid HA3204EB-1E, weight average molecular weight: 86,000, hydroxyl value: 30 mgKOH / g, acid value: 4.6 mgKOH / g, glass transition point: 70 ° C., resin content 45% by mass, ethyl acetate / butyl acetate mixed solution, manufactured by Hitachi Chemical Co., Ltd.)
B-1: PO-modified diacrylate (trade name: APG-400, average PO chain length = 7, manufactured by Shin-Nakamura Chemical Co., Ltd.)
B-2: PO-modified diacrylate (trade name FA-P240A, average PO chain length = 7, manufactured by Hitachi Chemical Co., Ltd.)
B-3: EO-modified bisphenol A diacrylate (trade name FA-321A, average EO chain length = 10, manufactured by Hitachi Chemical Co., Ltd.)
B-4: EO-modified bisphenol A dimethacrylate (trade name FA-321M, average EO chain length = 10, manufactured by Hitachi Chemical Co., Ltd.)
C-1: Glyoxyester photoinitiator (oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester mixture) (trade name) IRGACURE754, Ciba Specialty Chemicals Co., Ltd.)
C-2: Phosphine oxide photoinitiator (2,4,6-trimethylbenzoyl-phenylphosphine oxide) (trade name DAROCUR-TPO, manufactured by Ciba Specialty Chemicals Co., Ltd.)
D-1: Phenolic antioxidant (3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2 4,8,10-tetraoxaspiro [5.5] undecane) (trade name ADK STAB AO-80, manufactured by ADEKA Corporation)

  In Examples 1-4, it has high transparency and high refractive index in the visible light wavelength region, and has excellent high temperature and high humidity reliability. On the other hand, in Comparative Examples 1 and 2, a high refractive index could not be obtained. In Comparative Example 3, the refractive index was high, but the transparency was poor.

  As described above, the photosensitive resin composition and the photosensitive resin varnish having high transparency in the visible light wavelength region, high heat and high humidity reliability, and further improving the refractive index in order to improve the light transmittance. The photosensitive resin film and the cured photosensitive resin obtained by photocuring the photosensitive resin film could be provided.

  The photosensitive resin composition of the present invention is a photosensitive resin composition having high transparency in the visible light wavelength region, high heat and high humidity reliability, and further improving the refractive index in order to improve light transmittance. , A photosensitive resin varnish, a photosensitive resin film, and a cured photosensitive resin obtained by photocuring these can be obtained. Therefore, they are optimal for uses such as a visible light guide path and a light guide material.

1. Substrate 2. 2. Light source the film

Claims (8)

A photosensitive resin for a visible light guide including (A) an acrylic polymer, (B) a polymerizable compound having an unsaturated double bond group , (C) a photopolymerization initiator, and (D) a hindered phenol-based antioxidant. A composition comprising:
The total content of the component (A) and the component (B) is 30 to 70% by mass of the component (A), and the content of the component (B) is 30 to 70% by mass.
The content of component (C) is 0.03 to 3.0 parts by mass, and the content of component (D) is 0.01 to 1 with respect to 100 parts by mass of the total amount of component (A) and component (B). 0.0 part by mass,
(B) a polymerizable compound having an unsaturated double bond group comprises a polymerizable compound having an aromatic,
The aromatic polymerizable compound is
Following formula (1)
(In the above formula, X ¹ and X ² are each a hydrogen atom or a methyl group, m and n are positive integers, and m + n is in the range of 2 to 14.)
The visible light , wherein the content of the aromatic polymerizable compound is 10 to 40% by mass with respect to the total amount of the component (A) and the component (B). A photosensitive resin composition for an optical path . The photosensitive resin composition for visible light guides according to claim 1 , wherein a refractive index of a cured product obtained by irradiating the photosensitive resin composition with light to be cured is 1.49 or more. The photosensitive resin for visible light guides according to claim 1 or 2 , wherein a light transmittance at a wavelength of 420 nm of a cured product obtained by irradiating the photosensitive resin composition with light is 92% or more at a thickness of 200 µm. Composition. The photosensitive resin composition for visible light guides according to any one of claims 1 to 3 , wherein a haze of a cured product obtained by irradiating the photosensitive resin composition with light to cure is 3% or less at a thickness of 200 µm. object. The photosensitive resin varnish for visible light light guides containing the photosensitive resin composition for visible light light guides of any one of Claims 1-4 , and an organic solvent. The photosensitive resin film for visible light guides formed by apply | coating the photosensitive resin varnish for visible light guides of Claim 5 on a base film, and drying. The photosensitive resin composition for visible light guides according to any one of claims 1 to 4 , the photosensitive resin varnish for visible light guides according to claim 5 , or the photosensitive resin for visible light guides according to claim 6. A cured photosensitive resin for a visible light guide , which is formed by irradiating light to a photosensitive resin film and curing. The visible light light guide which consists of a photosensitive resin hardened | cured material for visible light light guides of Claim 7 .