JP2012093708A - Photosensitive resin composition for visible light guide path, cured body thereof, and visible light guide path - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin composition for visible light guide path that has high transparency in a visible light wavelength range and superior heat-resistance and moisture-resistance reliability, improves a refractive index, and has superior plasticity, a cured body thereof, and a visible light guide path.SOLUTION: There is provided the photosensitive resin composition for visible light guide path which contains a polymerizable compound (A), a photoinitiator (B), and a hindered phenolic antioxidant (C), and contains, as the component (A), a compound (A-1) including one polymerizable group in one molecule and a compound (A-2) including two or more polymerizable groups in one molecule and, as the component (C), at least one or more kinds of semi-hindered phenolic antioxidant or less hindered phenolic antioxidant. Also, there are provided the cured body obtained by curing the photosensitive resin composition for visible light guide path by irradiation with light; and the visible light guide path using the cured body.

Description

  The present invention relates to a photosensitive resin composition for a visible light guide, a cured product obtained by irradiating light to the photosensitive resin composition, and a visible light guide. More specifically, a photosensitive resin composition for a visible light guide and a cured product having excellent transparency in the visible light wavelength region and capable of obtaining a cured product with less deterioration such as coloring in a high-temperature and high-humidity reliability test, and using the same It relates to a visible light guide obtained.

  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, so that 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 illumination 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 that they are inferior in heat resistance reliability and moisture resistance reliability.

Therefore, 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 are used. In these methods, a resin material is supplied to a casting mold to perform molding. However, when a varnish obtained by dissolving a resin with a solvent is used as a resin material, voids and molding defects are generated due to pressure heating. Therefore, as the resin material to be supplied to the casting mold, a liquid resin that does not contain a solvent is used, and a liquid having a photosensitivity is poured into a mold having an arbitrary shape, or the liquid is cast into a place where the liquid is cast. By holding down with a mold and irradiating light, three-dimensional cross-linking / insolubilization is possible, and a member having a complicated shape can be easily formed.
In general, materials having photosensitivity and good optical characteristics, in particular, transparency in the visible light region have been studied (for example, see Patent Documents 1 and 2). However, these materials use a high-viscosity copolymer as a raw material from the viewpoints of heat resistance, solubility in an alkaline aqueous solution, and toughness, and therefore a solvent is required during the synthesis of the copolymer.

  When used as a light guide, the light propagation layer (core layer) is covered with a layer having a refractive index lower than that of the core layer (cladding layer) or air so that light can be propagated more efficiently. Can be done. If the refractive index difference between the core layer and the clad layer is small, light leakage from the core layer to the clad layer occurs, and the light propagation efficiency decreases. Therefore, in order to improve the light transmittance, the core layer material has been required to have an improved refractive index.

International Publication No. 2009/066668 JP 2001-288206 A

  The present invention is excellent in high transparency and high temperature and high humidity reliability in the visible light wavelength region of 380 to 780 nm, and has high light transmittance by improving the refractive index and excellent moldability by reducing the viscosity. Another object is to provide a photosensitive resin composition for a visible light guide, a cured product thereof, and a visible light guide.

  As a result of repeated studies to solve the above-mentioned problems, the present inventors, as a polymerizable compound, include a compound containing one polymerizable group in one molecule and a compound containing two or more polymerizable groups in one molecule. When used, it has been found that a cured product having high transparency in the visible light wavelength region, excellent high-temperature and high-humidity reliability, improved refractive index, and excellent formability can be obtained, and the present invention has been completed. It was.

That is, the present invention
(1) A photosensitive resin composition for a visible light guide comprising (A) a polymerizable compound, (B) a photopolymerization initiator, and (C) a hindered phenol-based antioxidant, the component (A) (A-1) a compound containing one polymerizable group in one molecule and (A-2) a compound containing two or more polymerizable groups in one molecule, and (C) component is a semi-hindered phenol type A photosensitive resin composition for a visible light guide, which contains at least one kind of an antioxidant or a hindered phenolic antioxidant,
(2) The photosensitive resin composition for a visible light guide according to (1), wherein the viscosity is 800 mPa · s or less,
(3) The ratio of the aromatic ring contained per unit mass of one molecule is 5.0 mmol / g or more for the component (A-1) and 2.0 mmol / g or more for the component (A-2). (1) or (2), the photosensitive resin composition for visible light guides,
(4) The photosensitive resin composition for visible light guides according to any one of (1) to (3), wherein the component (A-1) is represented by the following formula (1):

(In the formula (1), a is an integer of 1 to 4, R ₁ is a hydrogen atom or a methyl group. X is a single bond or a divalent group represented by any of the following.)

(5) The photosensitive resin composition for visible light guides according to any one of (1) to (4), wherein the component (A-2) is represented by the following formula (2):

(In formula (2), b + c is an integer of 1 to 14, R ₂ , R ₃ , R ₅ and R ₆ are each a hydrogen atom or a methyl group, and R ₄ is represented by any of the following: It is a divalent group.)

(6) The photosensitive resin composition for visible light guides according to any one of (1) to (5), wherein the component (C) is a semi-hindered phenolic antioxidant.
(7) The photosensitive resin composition for visible light guides according to any one of (1) to (5), wherein the component (C) includes at least one of those represented by the following formula (3) or (4): ,

(8) The content of the component (A-1) is 20 to 80 parts by mass and the content of the component (A-2) is 20 to 80 parts by mass in 100 parts by mass of the photosensitive resin composition for a visible light guide. (1)-the photosensitive resin composition for visible light guides in any one of (7),
(9) A cured product obtained by irradiating and curing the photosensitive resin composition for visible light guides according to any one of (1) to (8) above,
(10) The cured product according to (9), wherein the cured product has a refractive index of 1.54 or more,
(11) A visible light guide using the cured product according to (9) or (10) above,
Is to provide.

  According to the present invention, a photosensitive resin composition for a visible light guide having excellent transparency and high temperature and high humidity reliability in the visible light wavelength region, improved refractive index, and reduced viscosity and excellent formability. It is possible to provide a cured product obtained by photocuring it and a visible light guide using the cured product.

  The photosensitive resin composition for a visible light guide according to the present invention comprises (A) a polymerizable compound, (B) a photopolymerization initiator, and (C) a photosensitive resin for a visible light guide that includes a hindered phenol-based antioxidant. A resin composition comprising (A-1) a compound containing one polymerizable group in one molecule and (A-2) a compound containing two or more polymerizable groups in one molecule as component (A) And it is the photosensitive resin composition for visible light light guides whose content of (C) component is 0.01 mass part-0.1 mass part with respect to 100 mass parts of (A) component.

  In the present invention, the polymerizable group contained in the polymerizable compound (A) is not particularly limited as long as it is polymerized by irradiation with light such as ultraviolet rays. For example, a compound having a polymerizable substituent such as an ethylenically unsaturated group Are preferable. From the viewpoint of the transparency of the resulting photosensitive resin composition for a visible light guide path, those that do not absorb light are particularly preferred in the visible light wavelength region of 380 to 780 nm. Moreover, although (A) polymeric compound can use solid, a semi-solid, and a liquid, it is preferable that it is a liquid from the viewpoint of the handleability of a photosensitive resin composition for visible light light guides, and a formability.

In the present invention, the compound containing one polymerizable group in one molecule (A-1) among the components (A) in the photosensitive resin composition for visible light guide channel is represented by the following formula (1). Compounds are preferred.

In formula (1), R ₁ is a hydrogen atom or a methyl group. X is a single bond or a divalent group represented by any of the following. Moreover, a is an integer of 1-4. When a is 5 or more, the ratio of the aromatic ring contained in the component (A-1) is less than 5.0 mmol / g, which is not preferable. And a is more preferably an integer of 1 to 3, and particularly preferably an integer of 1 to 2. In addition, the ratio (aromatic ring equivalent) of the aromatic ring contained per unit mass of one molecule of the polymerizable compound can be obtained by dividing the number of aromatic rings contained in one molecule by the molecular weight.

  Examples of the compound (A-1) that includes one polymerizable group in one molecule include ethoxylated o-phenylphenol (meth) acrylate, p-cumylphenoxyethylene glycol (meth) acrylate, and p-benzylphenoxy. Examples include ethylene glycol (meth) acrylate and 4-phenoxyphenyl ethylene glycol (meth) acrylate.

In addition, among the components (A) in the photosensitive resin composition for a visible light guide, (A-2) the compound represented by the following formula (2) is a compound containing two or more polymerizable groups in one molecule. Is preferred.

(In formula (2), b + c is an integer of 1 to 14, R ₂ , R ₃ , R ₅ and R ₆ are each a hydrogen atom or a methyl group, and R ₄ is represented by any of the following: It is a divalent group.)

  b + c is in the range of 1 to 14, more preferably in the range of 1 to 10, and particularly preferably in the range of 1 to 8. When b + c is larger than 14, the ratio (aromatic ring equivalent) of the aromatic ring contained in the component (A-2) is less than 2.0 mmol / g, which is not preferable. In addition, the ratio of the aromatic ring contained per unit mass of one molecule of the polymerizable compound is obtained by dividing the number of aromatic rings contained in one molecule by the molecular weight.

  The compound containing two or more polymerizable groups in one molecule as the component (A-2) includes ethoxy modified bisphenol A di (meth) acrylate, ethylene oxide modified bisphenol A di (meth) acrylate, propylene oxide modified bisphenol A di (Meth) acrylate, ethylene oxide modified bisphenol F di (meth) acrylate, propylene oxide modified bisphenol F di (meth) acrylate, 9,9′-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene, and the like.

  In the present invention, the ratio of the aromatic ring contained per unit mass of one molecule of the polymerizable compound (A) is 5.0 mmol / g or more for the component (A-1) and 2.0 mmol for the component (A-2). / G or more is preferable. From the viewpoint of improving the refractive index of the cured product obtained by irradiating light to the photosensitive resin composition for visible light guide and compatibility of (A) polymerizable compound, it is contained per unit mass of (A) polymerizable compound. More preferably, the ratio of the aromatic ring is 5.5 mmol / g or more for the component (A-1) and 2.5 mmol / g or more for the component (A-2). (A) If the ratio of the aromatic ring contained per unit mass of the polymerizable compound is 5.0 mmol / g or more for the component (A-1) or 2.0 mmol / g or more for the component (A-2) The refractive index of the cured product obtained by irradiating the photosensitive resin composition for the visible light guide channel with light is 1.54 or more, and (A) the compatibility of the polymerizable compound and the transparency in the visible light wavelength region are also good. It is.

  In the present invention, in 100 parts by mass of the photosensitive resin composition for a visible light guide, the content of the component (A-1) is 20 to 80 parts by mass, and the content of the component (A-2) is 20 to 80 parts by mass. It is preferable that If the content of the component (A-1) in the photosensitive resin composition for a visible light guide is 20 parts by mass or more and the content of the component (A-2) is 80 parts by mass or less, the photosensitivity for the visible light guide is shown. The number of reaction points in the resin composition does not increase, and the curing shrinkage of the cured product obtained by irradiating the photosensitive resin composition for a visible light guide channel with light does not increase. On the other hand, if the content of the component (A-1) is 80 parts by mass or less and the content of the component (A-2) is 20 parts by mass or less, there are few reaction points in the photosensitive resin composition for visible light guide. Therefore, the three-dimensional cross-linking of the cured product is densified, and bleed-out of the unreacted component (A-1) does not occur, so that high temperature and high humidity reliability does not decrease. Therefore, from the viewpoint of reduction in curing shrinkage and high temperature and high humidity reliability of a cured product obtained by irradiating light to the photosensitive resin composition for visible light guide, in 100 parts by weight of the photosensitive resin composition for visible light guide, More preferably, the content of the component A-1) is 30 to 70 parts by mass, and the content of the component (A-2) is 30 to 70 parts by mass. And in 100 mass parts of photosensitive resin compositions for visible light guides, content of (A-1) component is 40-60 mass parts, and content of (A-2) component is 40-60 mass parts. Is more preferable.

  The viscosity of the photosensitive resin composition for visible light guides, comprising (A) a polymerizable compound, (B) a photopolymerization initiator, and (C) a hindered phenol-based antioxidant is 800 mPa · s or less. preferable. When the viscosity of the photosensitive resin composition for a visible light guide channel is 800 mPa · s or less, when the liquid photosensitive resin composition for a visible light guide channel is filled into an arbitrary shape by a casting method or a transfer method, Filled parts and voids do not occur, and handling at the time of molding is good. From the viewpoint of molding processability, the viscosity of the photosensitive resin composition for a visible light guide is more preferably 600 mPa · s or less, and particularly preferably 500 mPa · s or less. In addition, the viscosity of the photosensitive resin composition for visible light guides can be measured under predetermined conditions using, for example, an E-type viscometer.

  Next, (B) the photopolymerization initiator will be described. The content of (B) the photopolymerization initiator is preferably in the range of 0.03 to 3.0 parts by mass when the total amount of the polymerizable compound (A) is 100 parts by mass. When the content of component (B) is 0.03 parts by mass or more, the curing reaction proceeds sufficiently by light irradiation. When it is 3.0 parts by mass or less, the influence of coloring derived from the component (B) does not increase, and the transparency in the visible light wavelength region is good. From the viewpoint of photocurability of the photosensitive resin composition for visible light guide and transparency in the visible light wavelength region, the content of component (B) is more preferably in the range of 0.1 to 1.5 parts by mass. preferable.

  (B) As a photopolymerization initiator, (B-1) at least one selected from an α-hydroxyacetophenone photoinitiator and a glyoxyester photoinitiator and (B-2) a phosphine oxide photoinitiator. It is preferable to contain. By using such a specific (B) polymerization 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 the component (B-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. Particularly preferred are ethyl esters and mixtures thereof, or 1-hydroxy-cyclohexyl phenyl ketone.

  As the phosphine oxide photoinitiator as the component (B-2), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine oxide, a mixture 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.

  The content of (C) hindered phenolic antioxidant is preferably in the range of 0.01 to 1.0 part by mass when the total amount of (A) polymerizable compound is 100 parts by mass. The range of 2 to 1.0 parts by mass is more preferable. When the content of (C) is 0.01 parts by mass or more, high-temperature and high-humidity reliability is good, and when it is 1.0 parts by mass or less, polymerization is not inhibited during photocuring.

  As the hindered phenolic antioxidant as the component (C), at least one kind of semi-hindered phenolic antioxidant or less hindered phenolic antioxidant is contained. When these are used, compared with the hindered phenolic antioxidant in which two sterically bulky groups exist in the ortho position of the phenolic hydroxyl group, the compatibility is high and the sterically bulky amount is not sufficient. Since the polymerization inhibition is small, the reactivity is high and the curability is good. Further, productivity is high because the amount of light irradiation required for curing is small. Furthermore, the thing containing an aromatic ring like a phenol type compound can improve heat-resistant reliability more.

  A sterically bulky group means a branched alkyl group or an aromatic ring group other than a linear alkyl group. Specifically, tertiary alkyl groups such as t-butyl group, t-pentyl group and t-hexyl group; secondary alkyl groups such as i-propyl group, sec-butyl group and sec-pentyl group; i-butyl Groups, branched primary alkyl groups such as i-pentyl group; cycloalkyl groups such as cyclohexyl group and cyclopentyl group; and aromatic ring groups such as phenyl group, benzyl group and naphthyl group. Among these, a tertiary alkyl group is more preferable, and a t-butyl group is particularly preferable in terms of achieving a balance between heat resistance reliability and curability.

  A semi-hindered phenolic antioxidant is one in which the hydrogen atom in one ortho position of the phenolic hydroxyl group is replaced with a sterically bulky group, and the hydrogen atom in the other ortho position is replaced with a methyl group. Say things. As a specific example, bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionic acid] [ethylenebis (oxyethylene)] (for example, Irganox 245 manufactured by BASF Japan Ltd.) 3,9-bis [1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4,8,10-tetraoxaspiro [ 5.5] Undecane (for example, Adeka Stub AO-80 manufactured by ADEKA Corporation), triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate (for example, Corporation) ADEKA manufactured by Adeka Stub AO-70).

  The hindered phenolic antioxidant is a compound in which a hydrogen atom at one ortho position of a phenol hydroxyl group is substituted with a sterically bulky group and a hydrogen atom at the other ortho position is not substituted. . As a specific example, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane (for example, Adeka Stab AO-30 manufactured by ADEKA Corporation), 4,4′-butylidenebis (6-tert-butyl-m-cresol) (for example, Adeka Stub AO-40 manufactured by ADEKA Corporation), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane (For example, ICI, Topanol CA), 4,4′-thiobis (6-tert-butyl-m-cresol) (for example, Sumitomo Chemical Co., Ltd., Sumitizer WX-R) 4,4′-butylidenebis ( 6-tert-butyl-m-cresol) (for example, Sumitizer BBM, manufactured by Sumitomo Chemical Co., Ltd.), 2-tert-butyl-4-methyl-6- (2) acrylate Hydroxy -3-tert-butyl-5-methylbenzyl) phenyl (e.g., Sumitomo Chemical Co., Ltd., Sumilizer GM) and the like.

  Among these, a semi-hindered phenolic antioxidant is more preferable in terms of a balance between heat resistance reliability and curability, and a compound represented by the following formula (3) or (4) is preferable. 3,9-bis [1,1-dimethyl-2-[(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4,8,10-tetraoxa Spiro [5.5] undecane is particularly preferred.

In addition to the components (A) to (C), in the photosensitive resin composition for a visible light guide according to the present invention, a yellowing inhibitor, an ultraviolet absorber, a visible light absorber, and a colorant are included as necessary. So-called additives such as plasticizers, stabilizers, fillers, and optical brighteners may be added in proportions that do not adversely affect the effects of the present invention.
In particular, in addition to the above components (A) to (C), in order to improve the releasability of the cured product obtained by irradiating light to the photosensitive resin composition for visible light guide, a release agent or leveling agent is used. It may be added. Examples of release agents and leveling agents include silicone compounds and olefin compounds.

When preparing the photosensitive resin composition for visible light guides of the present invention, 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, the components (A) to (C) are sufficiently mixed, and when it is 1,000 min ⁻¹ or less, bubbles are less likely to be involved due to the rotation of the propeller. More preferably more than a 50～800Min ^-1 in view, it is more 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. When it is 1 hour or longer, the respective components (A) to (C) are sufficiently mixed, and when it is 24 hours or shorter, the preparation time can be shortened and sufficient productivity is obtained.

  It is preferable to filter the prepared photosensitive resin composition for visible light guides using a filter having a pore diameter of 50 μm or less. By using a filter having a pore diameter of 50 μm or less, large foreign matters and the like are removed, and no repelling occurs at the time of application, 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 more preferable to filter using a filter having a pore diameter of 10 μm or less.

  It is preferable that the prepared photosensitive resin composition for a visible light guide channel is defoamed 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 component of the photosensitive resin composition for visible light light guides does not volatilize 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, bubbles dissolved in the photosensitive resin composition for a visible light guide can be removed. If it is 60 minutes or less, the components contained in the photosensitive resin composition for a visible light guide path will not volatilize.

The photosensitive resin composition for visible light guides of the present invention can be quickly cured with light. 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 reaction rate of the cured product was calculated on the basis of a change in C—H bending vibration absorption intensity (near 800 cm ⁻¹ ) derived from an acrylic group by measuring an infrared absorption spectrum using a KBr method tablet.
The type of light is not particularly limited as long as the curing reaction proceeds, but the light is preferably UV light from the viewpoint of fast curing, and (B) UV light from the viewpoint of the absorption wavelength of the photoinitiator polymerizer. Among these, it is more preferable to cure with 365 nm i-line. The light source that emits 365-nm i-rays is not particularly limited. 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. Dose necessary for curing, the cured product of which varies in thickness and refractive index such as seeking, in general at an illuminance 1 to 100 mW / cm ^2, to obtain a cured product by irradiating 10 to 10000 mJ / cm ² be able to.

  In the visible light region of 380 to 780 nm, the obtained cured product preferably has a light transmittance of 90% or more, more preferably 91% or more, and 92% or more in a test piece having a thickness of 200 μm. Is particularly preferred. When such a cured product is used, light can be propagated without reducing the illuminance of light and without changing the color of the light source. If the light transmittance is lower than 90%, it is not preferable because light cannot be sufficiently propagated and the light source is changed in color.

Hereinafter, the cured product of the present invention will be described.
The cured product of the present invention comprises the above-mentioned photosensitive resin composition for a visible light guide, and the photosensitive resin composition for a visible light guide is injected or cast into a mold having an arbitrary shape placed on a substrate. It is obtained by forming a resin layer (hereinafter sometimes referred to simply as “resin layer”), attaching a protective film to the resin layer, sealing it, irradiating with light, and curing. The refractive index of the cured product of the present invention is preferably 1.54 or more, more preferably 1.55 or more, and particularly preferably 1.555 or more.

  Here, the substrate is not particularly limited. For example, glass, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and other polyesters; polyethylene, polypropylene, polyethylene-vinyl acetate copolymer and other polyolefins; polyvinyl chloride, polychlorinated Examples include vinylidene, polycarbonate, polyamide, polyimide, polyamideimide, polyetherimide, polyethersulfide, polyethersulfone, polyetherketone, polyphenyleneether, polyphenylenesulfide, polyarylate, polysulfone, and liquid crystal polymer.

Moreover, although the thickness of a board | substrate may change suitably with the shape and thickness of the target hardened | cured material, it is preferable that it is 50-1500 micrometers. If it is less than 50 μm, it is difficult to maintain the shape of the photosensitive resin layer, and if it exceeds 1500 μm, the irradiation intensity of light in the curing step is lowered, and curing failure of the photosensitive resin layer occurs. From the above points, the thickness of the base film is more preferably 100 to 1250 μm. In addition, in order to improve peelability from the resin layer, a substrate 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 material of the mold for injecting or casting the photosensitive resin composition for the visible light guide is not particularly limited. However, considering the heat generated by curing of the resin layer and the heat storage by light irradiation, it is made of heat-resistant silicon or glass. Preferably there is.

  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, polyesters such as polyethylene terephthalate; polyolefins such as polyethylene and polypropylene are preferable from the viewpoints of flexibility and toughness. 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 1500 μm. If it is less than 10 μm, the film strength is insufficient, and if it exceeds 1500 μm, the irradiation intensity of light in the curing step is lowered, and the resin layer is not cured properly. From the above points, the thickness of the protective film is more preferably 15 to 1250 μm.

  The visible light guide photosensitive resin composition of the present invention and a cured product using the same can be used for a protective film, a surface coating material, a visible light guide or the like that requires high transmittance, and in particular, a visible light guide. Suitable for

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 for visible light guide channel In a brown plastic bottle with a capacity of 250 mL, (A) as a polymerizable compound (A-1) NK ester A- as a compound containing one polymerizable group in one molecule 120 g of CMP-1E (p-cumylphenoxyethylene glycol acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.) and (A-2) funcryl FA-326A as a compound containing at least two polymerizable groups in one molecule 80 g of (ethoxy-modified bisphenol A dimethacrylate, average ethoxy chain length = 10, manufactured by Hitachi Chemical Co., Ltd.), (B) Irgacure 754 (2- [2-oxo-2-phenylacetoxyoxyoxyacetic acid) as a photopolymerization initiator Ethoxy] ethyl ester, a mixture of oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester, B 0.2 g of SF Japan Co., Ltd.), 0.2 g of DAROCURE TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide, BASF Japan Co., Ltd.), (C) as a phenolic antioxidant 0.2 g of ADK STAB AO-80 (hindered phenol antioxidant, manufactured by ADEKA Corporation) was blended, and stirred at room temperature for 12 hours at a rotation speed of 400 min ⁻¹ using a propeller. The obtained mixture was subjected to pressure filtration using a membrane filter having a pore diameter of 2 μm, and vacuum degassed with 10 mmHg (= 1333 Pa) to prepare a photosensitive resin composition for a visible light guide.

2) Measurement of viscosity The viscosity was measured about the obtained photosensitive resin composition for visible light light guides. An E-type viscometer (trade name VISCONIC ELD manufactured by Toki Sangyo Co., Ltd.) was used, the measurement temperature was 25 ° C., the sample was 0.4 mL, and the rotation speed was 20 min ⁻¹ . The results are shown in Table 1.

3) Formation of photosensitive resin layer The visible light guide photosensitive resin composition prepared in 1) is injected into a silicon mold (manufactured by ASONE Co., Ltd., thickness 0.5 mm) placed on a glass substrate. Subsequently, it sticked so that the non-processed surface of an easily-adhesive PET film (Teijin DuPont Films make, brand name A4100, thickness 50 micrometers) might contact a photosensitive resin as a protective film, and the photosensitive resin layer was obtained.

4) Preparation of cured product 300 mJ / cm ^{2 of} the photosensitive resin layer obtained in 3) using a parallel exposure machine (trade name UV-330, manufactured by Oak Manufacturing Co., Ltd.) from the highly adhesive PET film. Irradiated with UV light. Then, the board | substrate, the type | mold, and the protective film were peeled off, the photocured material was obtained, and it used for various measurements. The results are shown in Table 1.

5) Evaluation of transmittance The transmittance was evaluated using the cured product (40 mm × 40 mm × 1 mm) obtained through the procedures of 3) and 4). Using a spectrophotometer U-3310 manufactured by Hitachi, Ltd., the transmittance was measured at a measurement wavelength of 200 to 800 nm. 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 90% (420 nm), 91% (560 nm), and 92% (780 nm), and the transparency was good.

6) Measuring method of white LED transmission intensity The white LED transmission intensity was measured using the cured product (10 mm × 100 mm × 0.5 mm) obtained through the procedures of 3) and 4). A side-emitting white LED was used as the light source, and light was emitted at an input current of 15 mA. The cured product was placed here, and white LED light (transmission intensity ratio of the light source = 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. from the end face on the opposite side. Calculation was performed according to equation (1).

Transmission intensity ratio = (Int ₄₆₀ / Int ₅₆₀ ) (1)

Int ₄₆₀ : Intensity of light peak mainly caused by B band (blue) seen in the vicinity of ₄₆₀ nm Int ₅₆₀ : Mainly caused by mixed light of G band (green) and R band (red) seen in the vicinity of ₅₆₀ nm Light peak intensity

In the evaluation of the transmission intensity ratio, a value smaller than 1.5 was evaluated as x, a value in the range of 1.5 to 2.0 was evaluated as ◯, and a value of 2.0 or more was evaluated as ◎.
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.

7) High-temperature and high-humidity reliability test The test piece evaluated in 6) was placed in an oven adjusted to 85 ° C. The LED was taken out after 250 hours, and the white LED transmission intensity was measured in the same manner as in 6). When the cured product of the photosensitive resin composition for visible light guide was evaluated, the transmission intensity ratio was 2.8, and the transmitted light was white light similar to the white LED light source.

8) Measurement of refractive index The refractive index was measured using the same test piece as used in 6). An Abbe refractometer T2 manufactured by Atago Co., Ltd. was used, the measurement wavelength was 589 nm (D line), and the measurement temperature was 25 ° C.

Examples 2-6 and Comparative Examples 1-3
According to the composition of Table 1 and Table 2, the photosensitive resin composition for visible light guides was obtained by the same operation as Example 1. A photocured product was prepared and evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

(Explanation in Table 1)
A-1-1: p-cumylphenoxyethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-CMP-1E, aromatic ring equivalent 6.5 mmol / g)
A-1-2: Ethoxylated o-phenylphenol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-LEN-10, aromatic ring equivalent 7.5 mmol / g)
A-2-1: Ethoxy-modified bisphenol A diacrylate (manufactured by Hitachi Chemical Co., Ltd., funcryl FA-326A, average ethoxy chain length = 6, aromatic ring equivalent 3.3 mmol / g)
A-2-2: Ethoxy-modified bisphenol A diacrylate (manufactured by Hitachi Chemical Co., Ltd., funcryl FA-324A, average ethoxy chain length = 4, aromatic ring equivalent 3.9 mmol / g)
B-1: Glyoxyester photoinitiator. Oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, mixture of oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester, manufactured by BASF Japan Ltd., Irgacure 754
B-2: α-hydroxyacetophenone initiator. 1-hydroxy-cyclohexyl phenyl ketone, manufactured by BASF Japan Ltd., Irgacure 184
B-3: Phosphine oxide photoinitiator. 2,4,6-trimethylbenzoyl-phenylphosphine oxide, manufactured by BASF Japan Ltd., DAROCUR TPO
C-1: Semi-hindered 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, manufactured by ADEKA Corporation, ADK STAB AO-80
C-2: Resinder type phenolic antioxidant, 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, manufactured by ADEKA Corporation, Adeka Stub AO-30

(Explanation in Table 2)
A-1-1: p-cumylphenoxyethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-CMP-1E, aromatic ring equivalent 6.5 mmol / g)
A-1-2: Ethoxylated o-phenylphenol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-LEN-10, aromatic ring equivalent 7.5 mmol / g)
A-2-1: Ethoxy-modified bisphenol A diacrylate (manufactured by Hitachi Chemical Co., Ltd., funcryl FA-326A, average ethoxy chain length = 6, aromatic ring equivalent 3.3 mmol / g)
A-2-2: Ethoxy-modified bisphenol A diacrylate (manufactured by Hitachi Chemical Co., Ltd., funcryl FA-324A, average ethoxy chain length = 4, aromatic ring equivalent 3.9 mmol / g)
A-2-3: Ethoxy-modified bisphenol A diacrylate (manufactured by Hitachi Chemical Co., Ltd., funcryl FA-321A, average ethoxy chain length = 10, aromatic ring equivalent 2.6 mmol / g)
B-1: Glyoxyester photoinitiator. Oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, mixture of oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester, manufactured by BASF Japan Ltd., Irgacure 754
B-3: Phosphine oxide photoinitiator. 2,4,6-trimethylbenzoyl-phenylphosphine oxide, manufactured by BASF Japan Ltd., DAROCUR TPO
C-1: 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10 -Tetraoxaspiro [5.5] undecane, manufactured by ADEKA, Adeka Stub AO-80
C-3: hindered phenolic antioxidant, 1,3,5-tris (3 ′, 5′di-t-butyl-4-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) Trion, manufactured by ADEKA Corporation, ADK STAB AO-20

As shown in Examples 1-7, the photosensitive resin composition for visible light guides of the present invention and the cured product obtained using the same are highly transparent in the visible light wavelength region, high temperature and high humidity reliability, and The refractive index and viscosity were within the specified range. And when a semi hindered phenolic antioxidant was used as the component (C), particularly good characteristics were obtained.
On the other hand, the cured product obtained using the photosensitive resin composition for visible light guides that does not contain the component (C) as in Comparative Example 1 had a reduced transmission intensity ratio after the high-temperature and high-humidity test.
And as in Comparative Examples 2-3, the viscosity of the photosensitive resin composition for a visible light guide channel not including the component (A-1) did not fall within a specified range.
Moreover, as in Comparative Example 4, the cured product obtained using the photosensitive resin composition for visible light guides that does not contain the component (A-2) is brittle, and the transmission intensity ratio decreased after the high-temperature and high-humidity test. .
Furthermore, as in Comparative Example 5, the cured product obtained using the photosensitive resin composition for visible light guide using a hindered phenolic antioxidant that is neither a semi-hindered type nor a less hindered type as the component (C), Not only was the curing insufficient, but the transmittance and transmission intensity ratio were low, and the refractive index of the cured product was less than 1.54.

As described above, the photosensitive resin composition for visible light guides, which is excellent in high transparency in the visible light wavelength region, excellent in heat and moisture resistance reliability, improved in refractive index, and reduced in viscosity and excellent in formability, and A cured product obtained by photocuring it could be provided.
Moreover, the photosensitive resin composition for visible light guides of this invention and its hardened | cured material are suitable for producing a visible light guide.

Claims (11)

  (A) A polymerizable compound, (B) a photopolymerization initiator, and (C) a photosensitive resin composition for a visible light guide including a hindered phenol-based antioxidant, and (A) as a component (A -1) a compound containing one polymerizable group in one molecule and (A-2) a compound containing two or more polymerizable groups in one molecule, wherein the component (C) is a semi-hindered phenolic antioxidant Or the photosensitive resin composition for visible light light guides which contains at least 1 or more types of a hindered type phenolic antioxidant.   The photosensitive resin composition for visible light guides according to claim 1, wherein the viscosity is 800 mPa · s or less.   The ratio of the aromatic ring contained per unit mass of one molecule is 5.0 mmol / g or more for the component (A-1) and 2.0 mmol / g or more for the component (A-2). The photosensitive resin composition for visible light guides according to claim 1 or 2. The photosensitive resin composition for visible light guides according to any one of claims 1 to 3, wherein the component (A-1) is represented by the following formula (1).

(In the formula (1), a is an integer of 1 to 4, R ₁ is a hydrogen atom or a methyl group. X is a single bond or a divalent group represented by any of the following.)

The photosensitive resin composition for visible light guides according to claim 1, wherein the component (A-2) is represented by the following formula (2).

(In formula (2), b + c is an integer of 1 to 14, R ₂ , R ₃ , R ₅ and R ₆ are each a hydrogen atom or a methyl group, and R ₄ is represented by any of the following: It is a divalent group.)

  The said (C) component is a semi-hindered phenolic antioxidant, The photosensitive resin composition for visible light guides in any one of Claims 1-5. The photosensitive resin composition for visible light guides according to any one of claims 1 to 5, wherein the component (C) contains at least one kind represented by the following formula (3) or (4).

  The content of the component (A-1) is 20 to 80 parts by mass and the content of the component (A-2) is 20 to 80 parts by mass in 100 parts by mass of the photosensitive resin composition for a visible light guide. The photosensitive resin composition for visible light guides in any one of -7.   Hardened | cured material obtained by irradiating light and hardening the photosensitive resin composition for visible light light guides in any one of Claims 1-8.   The cured product according to claim 9, wherein the cured product has a refractive index of 1.54 or more.   A visible light guide using the cured product according to claim 9 or 10.