JP5573329B2 - 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, it has excellent transparency in the visible light wavelength region, has little deterioration such as coloring in a high-temperature, high-humidity reliability test, and has a photosensitivity that can be a cured product having flexibility and excellent mechanical properties. The present invention relates to a resin composition, a photosensitive resin varnish, a photosensitive resin film, and a cured photosensitive resin obtained by photocuring these. In addition, the cured photosensitive resin of the present invention is developed especially for use in a visible light guide.

  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

However, in the above materials, in order to ensure transparency with visible light, the amount of photoinitiator added is increased to reduce the amount of unreacted polymerizable compound. Caused problems such as thermal deterioration and poor high temperature and high humidity reliability. Furthermore, since the material properties are insufficiently flexible, cracks may occur when a member is formed with a mold.
The present invention has been made in order to solve the above problems, and is a cured product having high transparency in the visible light wavelength region of 380 to 780 nm, excellent high-temperature and high-humidity reliability, and flexibility capable of forming a mold. It is an object to provide a photosensitive resin composition, a photosensitive resin varnish, a photosensitive resin film, a photosensitive resin cured product obtained by photocuring these, and a visible light guide path made of the photosensitive resin cured product. And

The present inventors have found that the following (1) to (5) solve the above problems.
(1) (A) acrylic polymer, (B) urethane (meth) acrylate, (C) (meth) acrylate other than component (B), (D) photopolymerization initiator, and (E) hindered phenol-based oxidation A photosensitive resin composition containing an inhibitor,
For the total amount of component (A), component (B), and component (C),
The content of the component (A) is 30 to 70% by mass, the content of the component (B) is 1 to 70% by mass, the content of the component (C) is 0 to 69% by mass,
The content of component (D) is 0.03 to 3.0 parts by mass and the content of component (E) with respect to 100 parts by mass of the total amount of component (A), component (B), and component (C). The photosensitive resin composition for visible light light guides whose is 0.01-1.0 mass part.
(2) The photosensitive resin varnish for visible light light guides containing the photosensitive resin composition of said (1) and an organic solvent.
(3) A photosensitive resin film for a visible light guide, which is obtained by applying the photosensitive resin varnish of (2) above onto a base film and drying it.
(4) The photosensitive resin composition for visible light guide path formed by irradiating and curing the photosensitive resin composition of (1), the photosensitive resin varnish of (2), or the photosensitive resin film of (3). Resin cured product.
(5) A visible light guide path comprising the cured photosensitive resin of (4).

  According to the present invention, a photosensitive resin composition, a photosensitive resin varnish, a photosensitive resin film, which can be a cured product having high transparency in the visible light wavelength region, high temperature and high humidity reliability, and excellent flexibility. In addition, it is possible to provide 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) urethane (meth) acrylate, (C) (meth) acrylate other than component (B), (D) a photopolymerization initiator, and ( E) A photosensitive resin composition obtained by containing a hindered phenol-based antioxidant.

  In this invention, content of (A) component is 30-70 mass% with respect to the total amount of (A) component, (B) component, and (C) component, and content of (B) component is 1-. 70% by mass, content of component (C) is 0 to 69% by mass, and content of component (D) is 100 parts by mass of component (A), component (B), and component (C) The amount is 0.03 to 3.0 parts by mass, and the content of the component (E) is 0.01 to 1.0 parts by mass.

[(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, (B) component, and (C) 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 35 to 60% by mass, more preferably 40 to 55 from the viewpoint of maintaining the processability of the photosensitive resin composition into a film and maintaining 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, In particular, homopolymers of the above monomers or two or more monomer copolymers selected from the above monomers are preferred.
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 of the acrylic polymer with the components (B) and (C) described later. From the above viewpoints, a specific (A) acrylic polymer is obtained using various monomers as necessary, and by using this, high transparency in the visible light wavelength region of the cured product obtained, and any It is possible to provide a photosensitive resin composition satisfying all of the glass transition temperature, the compatibility with the component (B) and the component (C).

(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 the obtained photosensitive resin cured product has sufficient strength and flexibility. In the high temperature and high humidity test, the occurrence of bleeding out of the low molecular weight 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, the appropriate viscosity of the photosensitive resin composition and the photosensitive resin composition varnish can be obtained, the processability to a film is excellent, and the obtained cured product has excellent flexibility. Is preferable. Moreover, since it has the outstanding compatibility with the (B) component and (C) component which are mentioned later, as a result, the haze of a photosensitive resin hardened | cured material can be suppressed 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) The hydroxyl value of the acrylic polymer is preferably in the range of 15 to 50 mgKOH / g. When the hydroxyl value of the component (A) is 15 mgKOH / g or more, a transparent photosensitive resin cured product having excellent compatibility with the components (B) and (C) described later can be obtained. On the other hand, if the hydroxyl value of (A) is 50 mgKOH / g or less, it is preferable because water absorption of the cured photosensitive resin can be suppressed and moisture absorption whitening can be suppressed in a high temperature and high humidity test.
From the above points, the hydroxyl value of the component (A) is more preferably in the range of 20 to 40 mgKOH / g, and particularly preferably in the range of 25 to 35 mgKOH / g.

(A) It is preferable that the acid value of an acrylic polymer is the range of 3.2-5.5 mgKOH / g. If the acid value of the component (A) is 3.2 mgKOH / g or more, it has excellent compatibility with the components (B) and (C) described later, and a transparent photosensitive resin cured product can be obtained. it can. On the other hand, if the acid value of (A) is 5.5 mgKOH / g or less, it is preferable because water absorption of the cured photosensitive resin can be suppressed and whitening of moisture can be suppressed in a high temperature and high humidity test.
From the above points, the acid value of the component (A) is more preferably in the range of 3.5 to 4.8 mgKOH / g, and particularly preferably in the range of 3.7 to 4.5 mgKOH / g.

(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) is 30 ° C. or more, the hardness of the obtained photosensitive resin cured product is sufficient, and the cured product can maintain its shape in a high temperature and high humidity reliability test, which 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. .

  As long as the (A) acrylic polymer is in the range of the above preferred weight average molecular weight, hydroxyl value, acid value, and glass transition point, the polymer structure, the polymerization method, and the type of polymerization reaction can be used. There is no limit. 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) Urethane (meth) acrylate]
(B) Content of urethane (meth) acrylate is the range of 1-70 mass% with respect to the total amount of (A) component, (B) component, and (C) component. When the content of the component (B) is less than 1% by mass, the transparency of the resulting photosensitive resin composition is lowered, the flexibility is further deteriorated, and a cured product of the photosensitive resin composition is formed with a mold. Sometimes cracks occur, which is not preferable. Moreover, when content of (B) component exceeds 70 mass%, since it is difficult to process the photosensitive resin composition into a film, it is unpreferable. From the viewpoint of processability, permeability and flexibility of the photosensitive resin composition, the content of the component (B) is more preferably in the range of 2 to 50% by mass, particularly preferably 3 to 20% by mass. % Range.

  The (B) urethane (meth) acrylate of the present invention is a (meth) acrylate having at least a urethane bond. (B) As urethane (meth) acrylate, for example, a urethane (meth) acrylate obtained by a reaction of a hydroxyl group-containing (meth) acrylate and a polyisocyanate or a reaction of a hydroxyl group-containing (meth) acrylate, a polyisocyanate and a polyol is used. it can. Among them, from the viewpoint of compatibility with the component (A) and the transparency and flexibility of the resulting photosensitive resin composition, the component (B) is preferably obtained by reacting a hydroxyl group-containing (meth) acrylate with a polyisocyanate. The urethane (meth) acrylate obtained is preferred.

  As urethane (meth) acrylate obtained by reaction of hydroxyl group-containing (meth) acrylate and polyisocyanate, for example, hydroxyethyl (meth) acrylate and 2,5- or 2,6-bis (isocyanatomethyl) -bicyclo [2. 2.1] Reaction product of heptane, reaction product of hydroxyethyl (meth) acrylate and 2,4-tolylene diisocyanate, reaction product of hydroxyethyl (meth) acrylate and isophorone diisocyanate, hydroxypropyl (meth) acrylate Product of 2,4-tolylene diisocyanate, reaction product of hydroxypropyl (meth) acrylate and isophorone diisocyanate, reaction product of phenylglycidyl ether (meth) acrylate and hexamethylene diisocyanate Reaction product of phenylglycidyl ether and toluene diisocyanate, reaction product of pentaerythritol tri (meth) acrylate and hexamethylene diisocyanate, reaction product of pentaerythritol tri (meth) acrylate and toluene diisocyanate, pentaerythritol tri (meth) acrylate Examples include a reaction product of isophorone disissocyanate, a reaction product of dipentaerythritol penta (meth) acrylate and hexamethylene diisocyanate.

  Among these, as (B) urethane (meth) acrylate, urethane (meth) acrylate containing (meth) acrylate represented by the following general formula (1) from the viewpoint of transparency and flexibility in the visible light wavelength region. It is preferable that

In the general formula (1), R ₁ represents hydrogen or an alkyl group having 1 to 12 carbon atoms, and R ₂ , R ₃ , and R ₄ each represents a divalent organic group having 1 to 20 carbon atoms. , M and n are integers from 0 to 50.

  Among the urethane (meth) acrylates represented by the general formula (1), those represented by the following formula (2) are particularly preferable from the viewpoints of transparency and flexibility in the visible light wavelength region. In addition, UA-13 (Shin-Nakamura Chemical Co., Ltd. product name) etc. are distribute | circulating as a commercial item, and following formula (2) is available.

[(C) (Meth) acrylate other than (B) component]
The component (C) is not particularly limited as long as it is a (meth) acrylate other than the component (B) and is polymerized by heating or irradiation with ultraviolet rays. The (meth) acrylate other than the component (B) means a (meth) acrylate having no urethane bond in the molecule, and specifically, a (meth) acrylate other than the above-described (B) urethane (meth) acrylate. It is.
(C) Content of (meth) acrylates other than (B) component is the range of 0-69 mass% with respect to the total amount of (A) component, (B) component, and (C) component. When the content of component (C) exceeds 69% by mass, it is not preferable because it is difficult to process the photosensitive resin composition into a film. 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 (C) is more preferably 20 to 60 mass. %, Particularly preferably in the range of 30 to 55% by mass.

  (C) Component (meth) acrylate having at least one functional group in one molecule that can be chain-polymerized by radicals emitted when light is irradiated to the photopolymerization initiator, and visible light wavelength region 400 Those having no light absorption in the range of ˜780 nm are preferred. As for the properties, any of solid, semi-solid and liquid can be used. Moreover, both monofunctional and bifunctional or more polyfunctional ones can be used. Specific examples of the compound include those described in International Publication WO2009 / 066668.

  In addition, the (meth) acrylate of the component (C) preferably contains at least one selected from bifunctional or higher polyfunctional polymerizable compounds. 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.

  Furthermore, as (meth) acrylate of (C) component, the compound represented by the following general formula (3) or (6) is mentioned suitably. This compound is preferable because it has excellent transparency in the visible light wavelength region, has an aromatic property, has excellent heat resistance, and is inexpensive.

In the general formula (3), R ₅ and R ₆ are each a hydrogen atom or a methyl group. R ₇ is represented by the following general formula (4).

In the general formula (4), a + b is in the range of 2 to 30, R ₈ and R ₉ are each hydrogen atom or a methyl group. R ₁₀ is any one of divalent groups represented by the following formula (5).

In the general formula (6), R ₁₁ and R ₁₂ are each a hydrogen atom or a methyl group. R ₁₃ is represented by the following general formula (7), (8) or (9).

In the general formulas (7), (8), and (9), R _{14 to} R ₁₉ 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.

[(D) 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, (B) component, and (C) component. When the content of the component (D) is less than 0.03 parts by mass, the curing reaction does not proceed sufficiently by light irradiation, which is not preferable. If it exceeds 3.0 parts by mass, the effect of coloring derived from the component (D) is increased, and as a result, the transparency in the visible light wavelength region is lowered, 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 (D) is 100 parts by mass of the total amount of the component (A), the component (B), and the component (C). Is preferably 0.1 to 1.5 parts by mass, and more preferably 0.1 to 1.0 parts by mass.

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

(D-1) α-hydroxyacetophenone photoinitiators include 1-hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxy Ethoxy) -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.

  (D-2) Examples of phosphine oxide photoinitiators include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine oxide, and mixtures thereof. It is done. 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.

[(E) hindered phenolic antioxidant]
(E) 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, (B) component, and (C) component. It is. If the content of (E) 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 (E) is 100 parts by mass with respect to the total amount of the component (A), the component (B), and the component (C). , Preferably it is 0.1-1.0 mass part, More preferably, it is 0.2-1.0 mass part.

  (E) 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 (10). 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 (10) is any of the divalent groups of the following formulas (11) and (12).

[Other photosensitive resin compositions]
In the photosensitive resin composition of the present invention, in addition to the above components (A) to (E), if necessary, the photosensitive resin composition of the present invention includes a yellowing inhibitor, an ultraviolet absorber, You may add what is called additives, such as a visible light absorber, a leveling agent, a coloring agent, a plasticizer, 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 Ethyl 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, Polyhydric alcohol alkyl ethers such as diethylene glycol dimethyl ether and diethylene glycol diethyl ether; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene Polyhydric alcohol alkyl ether acetates such as glycol 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 (E) 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. When it is 1 hour or longer, each of the components (A) to (E) and the organic solvent is sufficiently mixed, and when 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 the said (A)-(E) 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 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 protective film is more preferably 5 to 200 μm, still more preferably 7 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, a cured product having sufficient strength can be obtained, and if it is 500 μm or less, drying can be performed sufficiently, the amount of residual solvent in the resin film is reduced, and the cured product of the film is heated. Sometimes foaming is less likely to occur.

  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 the light is preferably UV light from the viewpoint of fast curing, and (D ) 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. Dose necessary for curing, the cured product of which varies in thickness and refractive index such as seeking, in general at an illuminance 1~1000mW / cm ^2, to obtain a cured product by irradiating 10 to 10000 mJ / cm ² be able to.

  It is preferable that the obtained cured product has a light transmittance of 90% or more in a test piece having a thickness of 200 μm in a visible light region of 380 to 780 nm. 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.

  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 (A) Acrylic polymer (meth) acrylate copolymer (Hitaroid 3204EB-1E, weight average molecular weight: 86,000, hydroxyl value: 121.6 g of 30 mg KOH / g, acid value: 3.8 mg KOH / g, glass transition point: 70 ° C., resin content 37% by mass, ethyl acetate / butyl acetate mixed solution, manufactured by Hitachi Chemical Co., Ltd.) B) As urethane (meth) acrylate, 5.0 g of UA-13 (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd.), and (NK) ester APG-400 ((meth) acrylate other than components (C) and (B)) Polypropylene glycol diacrylate; average PO chain length = 7, manufactured by Shin-Nakamura Chemical Co., Ltd. 25.0 g and FANCLIL FA-321M (EO modified bisphenol) 25.0 g of enol A dimethacrylate; average EO chain length = 10, manufactured by Hitachi Chemical Co., Ltd., (D) As a photopolymerization initiator, I-754 (oxyphenylacetic acid 2- [2-oxo-2- Phenylacetoxyethoxy] ethyl ester, oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester mixture, 0.3 g of Ciba Specialty Chemicals Co., Ltd.), D-TPO (2,4,6-trimethylbenzoyl) -0.3 g of diphenylphosphine oxide, a product name of Ciba Specialty Chemicals Co., Ltd.) (E) As a phenolic antioxidant, Adekastab AO-80 (hindered phenolic antioxidant, product of ADEKA Co., Ltd.) Name) 0.2 g and acetone 10 g, and stirred at room temperature for 12 hours using a mix rotor It was. 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) 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 the transmitted light using the “Multi-photometric system MCPD-3000” manufactured by Otsuka Electronics Co., Ltd. from the end face on the opposite side, and calculate the transmission intensity ratio from the peak intensity of the emitted light. It calculated according to the following formula.

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 1.5 or more, and more preferably 2.0 or more. Accordingly, those having a transmission intensity ratio of less than 1.5 were rated as x, those having a transmittance of 1.5 or more but less than 2.0 were marked as ◯, and those having a transmission intensity ratio of 2.0 or more 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.

(5) High-temperature and high-humidity reliability test The test piece evaluated in (4) 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 (4) after 250 hours, the transmission intensity ratio was 2.0, and the transmitted light was white light similar to the white LED light source.

(6) Folding test (evaluation of flexibility)
A sample obtained by cutting the cured product obtained in (3) into 1 cm × 8 cm size was used for evaluation. At an evaluation temperature of 23 ° C., this film was folded in two in the longitudinal direction, a load of 400 g per unit area was repeatedly applied, and the number of times that the film was not cracked was recorded.
When the number of times before the sample broke was 0 to 3 times x, 4 to 10 times were more than Δ, and 10 times, the flexibility of the cured product was evaluated.

[Examples 2 to 18 and Comparative Example 1]
According to the composition of Table 1 and Table 2, operation similar to Example 1 was performed and the photosensitive resin composition was obtained. 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 Tables 1 and 2)
A-1: HA3204EB-1E (acryl acrylate copolymer; hitaloid 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% by mass, mixed solution of ethyl acetate / butyl acetate, manufactured by Hitachi Chemical Co., Ltd.)
B-1: APG-400 (polypropylene glycol diacrylate; average PO chain length = 7, manufactured by Shin-Nakamura Chemical Co., Ltd.)
B-2: FA-321M (EO-modified bisphenol A dimethacrylate; average EO chain length = 10, manufactured by Hitachi Chemical Co., Ltd.)
C-1: UA-13 (EO, PO-modified urethane dimethacrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.)
C-2: UA-21 (made by Shin-Nakamura Chemical Co., Ltd.)
C-3: U-412A (urethane acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.)
C-4: UA-160TM (urethane acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.)
C-5: UF-8001G-20M (urethane acrylate; manufactured by Kyoeisha Chemical Co., Ltd.)
C-6: U-200PA (urethane acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.)
C-7: UA-4200 (urethane acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.)
C-8: UA-1137 (urethane acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.)
C-9: UA-7100 (urethane acrylate; manufactured by Shin-Nakamura Chemical Co., Ltd.)
D-1: I-754 (glyoxyester photoinitiator; oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, oxyphenylacetic acid 2- (2-hydroxyethoxy) ethyl ester mixture , Manufactured by Ciba Specialty Chemicals Co., Ltd.)
D-2: D-TPO (phosphine oxide photoinitiator; 2,4,6-trimethylbenzoyl-phenylphosphine oxide, manufactured by Ciba Specialty Chemicals Co., Ltd.)
E-1: AO-80 (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)

As shown in Examples 1 to 18, the photosensitive resin composition and the cured photosensitive resin film of the present invention have high transparency, excellent high-temperature and high-humidity reliability, and excellent flexibility. It was.
On the other hand, as in Comparative Example 1, when it does not contain (C) urethane (meth) acrylate, it is easy to break in the hull fold test, so that a photosensitive resin composition that can be a cured product having excellent flexibility is obtained. I could not.

  As described above, a photosensitive resin composition, a photosensitive resin varnish, and a photosensitive resin film that can be a cured product having high transparency in the visible light wavelength region, high heat and high humidity reliability, and excellent flexibility. And a cured photosensitive resin obtained by photocuring it.

  The photosensitive resin composition of the present invention is a photosensitive resin composition that has high transparency in the visible light wavelength region, high heat and high humidity reliability, and can be a cured product excellent in flexibility. , A photosensitive resin film, and a cured photosensitive resin obtained by photocuring these can be obtained. Therefore, they are optimal for applications such as optical waveguides and light guide materials.

1 Substrate 2 Light source 3 Sample

Claims (10)

(A) acrylic polymer, (B) urethane (meth) acrylate, (C) (meth) acrylate other than component (B), (D) photopolymerization initiator, and (E) hindered phenol antioxidant A photosensitive resin composition comprising:
For the total amount of component (A), component (B), and component (C),
The content of the component (A) is 30 to 70% by mass, the content of the component (B) is 1 to 70% by mass, the content of the component (C) is 0 to 69% by mass,
For 100 parts by mass of the total amount of component (A), component (B), and component (C),
The photosensitive resin for a visible light guide , wherein the content of the component (D) is 0.03 to 3.0 parts by mass, and the content of the component (E) is 0.01 to 1.0 parts by mass. Composition. 2. The polymer according to claim 1, wherein the acrylic polymer (A) is 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. Photosensitive resin composition for visible light guide . The photosensitive resin composition for visible light guides according to claim 1 or 2, wherein the acrylic polymer (A) has a weight average molecular weight in the range of 30,000 to 300,000. The photosensitive resin composition for visible light guides according to any one of claims 1 to 3, wherein the glass transition point of the (A) acrylic polymer is in the range of 30 to 100 ° C. The photosensitive resin composition for visible light guides according to any one of claims 1 to 4, wherein the (B) urethane (meth) acrylate is obtained by a reaction between a hydroxyl group-containing (meth) acrylate and a polyisocyanate. The photosensitive resin composition for visible light guides according to any one of claims 1 to 5, wherein the (B) urethane (meth) acrylate contains (meth) acrylate represented by the following general formula (I).
(In the formula (I), R ₁ represents hydrogen or an alkyl group having 1 to 12 carbon atoms, R ₂ , R ₃ and R ₄ each represents a divalent organic group having 1 to 20 carbon atoms, m and n are integers from 0 to 50.) The photosensitive resin varnish for visible light light guides containing the photosensitive resin composition of any one of Claims 1-6, and an organic solvent. The photosensitive resin film for visible light light guides formed by apply | coating the photosensitive resin varnish of Claim 7 on a base film, and drying. The photosensitive resin composition according to claim 1, the photosensitive resin varnish according to claim 7, or the photosensitive resin film according to claim 8 is irradiated with light and cured. A cured photosensitive resin for visible light guide .   A visible light guide path comprising the cured photosensitive resin according to claim 9.