CN114173469A

CN114173469A - Method for manufacturing light reflection substrate

Info

Publication number: CN114173469A
Application number: CN202111062967.9A
Authority: CN
Inventors: 中村洋介; 渡边真俊
Original assignee: Ajinomoto Co Inc
Current assignee: Ajinomoto Co Inc
Priority date: 2020-09-11
Filing date: 2021-09-10
Publication date: 2022-03-11
Also published as: TW202229435A; KR20220034680A; JP2022047123A

Abstract

[ problem ] to]A method for manufacturing a light-reflecting substrate exhibiting excellent base adhesion is provided. [ solution means ] to]A method for manufacturing a light-reflecting substrate, which comprises the following steps (A) and (B) in this order. (A) A substrate having a conductor layer on at least a part of the surface thereof and including a supportA step of laminating a body and a resin sheet provided on the support and containing a resin composition layer of a white inorganic pigment so that the resin composition layer is bonded to a conductor layer of a substrate; (B) a step of thermally curing the resin composition layer by satisfying at least one of the following conditions (i) and (ii), (i) at a temperature T₁After the heat treatment for holding, the temperature is controlled at a specific temperature T₁High temperature T₂Heating treatment by holding, (ii) raising the temperature to a temperature T at a temperature raising rate of 0.5 to 30 ℃/min₂Then, it is carried out at a temperature T₂Then, the heat treatment for holding is performed.

Description

Method for manufacturing light reflection substrate

Technical Field

The present invention relates to a method for manufacturing a light reflective substrate.

Background

Printed circuit boards are increasingly used in applications where Light Emitting Diodes (LEDs) that emit light at low power, such as backlights for liquid crystal displays of mobile terminals, computers, televisions, and the like, and light sources for lighting fixtures, are directly mounted. In recent years, LEDs have been miniaturized, and there are LEDs called small LEDs and micro LEDs.

A reflective sheet for reflecting light is formed on the outermost layer of such a printed circuit board in order to improve the efficiency of extracting light emitted from the light source. The printed wiring board provided with the reflection sheet is also referred to as a "light reflection substrate".

As a material of a reflective sheet of such a light reflective substrate, for example, patent document 1 discloses a resin composition containing a binder polymer and crosslinked polymer particles containing a white inorganic pigment.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5797279.

Disclosure of Invention

Problems to be solved by the invention

However, the inventors of the present invention have studied and found that: when a cured product (reflective sheet) is formed by thermally curing a resin composition containing a white inorganic pigment, the adhesion between the cured product and the conductor layer of the base substrate (hereinafter also simply referred to as "base adhesion") in the obtained light-reflecting substrate varies.

The present invention addresses the problem of providing a method for manufacturing a light-reflecting substrate that exhibits good base adhesion.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that: the present inventors have found that a light-reflecting substrate exhibiting good base adhesion can be produced by laminating a resin composition containing a white inorganic pigment on a base substrate and then thermally curing the resin composition under specific conditions, thereby completing the present invention.

That is, the present invention includes the following.

[1] A method for manufacturing a light-reflecting substrate, which comprises the following steps (A) and (B) in this order.

(A) A step of laminating a resin sheet including a support and a resin composition layer containing a white inorganic pigment provided on the support on a substrate (hereinafter referred to as a "base substrate") having a conductor layer on at least a part of a surface thereof, so that the resin composition layer is bonded to the conductor layer of the base substrate;

(B) a step of thermally curing the resin composition layer while satisfying at least one of the following conditions (i) and (ii),

(i) at a temperature T₁After the heat treatment for holding, the temperature is controlled at a specific temperature T₁High temperature T₂Then, the heating treatment for holding is carried out,

(ii) heating the mixture to a temperature T at a heating rate of 0.5-30 ℃/min₂Then, it is carried out at a temperature T₂Then, the heat treatment for holding is performed.

[2] The method according to [1], wherein the support is peeled between the step (A) and the step (B).

[3] The method according to [1] or [2], wherein the resin composition layer further contains a thermosetting resin.

[4] The method according to any one of [1] to [3], wherein the content of the white inorganic pigment is 20 to 60% by mass, assuming that 100% by mass of nonvolatile components in the resin composition layer are present.

[5] The method according to [3] or [4], wherein the thermosetting resin comprises an epoxy resin.

[6] The method according to [5], wherein the content of the epoxy resin is 1 to 50% by mass, based on 100% by mass of nonvolatile components in the resin composition layer.

[7] The method according to any one of [1] to [6], wherein the white inorganic pigment is 1 or more selected from the group consisting of alumina, titania, zirconia, magnesia, barium titanate, zinc oxide, cerium oxide and calcium carbonate.

[8] The method according to any one of [1] to [7], wherein the light-reflecting substrate exhibits a reflectance of 85% or more with respect to light having a wavelength of 460 nm.

[9] The method according to any one of [1] to [8], wherein the adhesion strength between a cured product of the resin composition layer in the light-reflecting substrate and the conductor layer of the base substrate is 0.3kgf/cm or more.

Effects of the invention

According to the present invention, a method for manufacturing a light reflective substrate exhibiting excellent base adhesion can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing an example of a light reflective substrate.

Detailed Description

Before describing the method for manufacturing the light reflective substrate of the present invention (hereinafter, also simply referred to as "the method of the present invention") in detail, a resin sheet used in the method of the present invention will be described.

< resin sheet >

The resin sheet used in the method of the present invention comprises a support and a resin composition layer containing a white inorganic pigment provided on the support.

(resin composition layer)

The resin composition layer contains a white inorganic pigment. This allows the cured product obtained by curing the resin composition layer to exhibit light reflection characteristics. In one embodiment of the present invention, the "white inorganic pigment" refers to an inorganic compound or an inorganic filler having a reflectance of 90% or more with respect to light having a wavelength of 500 nm.

White inorganic pigments

Examples of the material of the white inorganic pigment include white metal oxides such as aluminum oxide (ALUMINA), titanium oxide, zirconium oxide, magnesium oxide, zinc oxide, cerium oxide, antimony oxide, tin oxide, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, barium zirconate, and calcium zirconate; white metal sulfides such as zinc sulfide and strontium sulfide; white metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; white metal nitrides such as boron nitride, aluminum nitride, and manganese nitride; white metal carbonates such as calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, and lead carbonate; white metal sulfates such as barium sulfate, calcium sulfate, and lead sulfate; white metal phosphates such as zinc phosphate, titanium phosphate, zirconium phosphate, and zirconium phosphotungstate; white metal borates such as aluminum borate; white minerals such as cordierite, talc, clay, mica, hydrotalcite and boehmite.

Of these, the white inorganic pigment is preferably selected from the group consisting of alumina, titania, zirconia, magnesia, barium titanate, zinc oxide, cerium oxide and calcium carbonate, and particularly preferably is titania. As the titanium oxide, any of rutile type, anatase type, and brookite type can be used, and from the viewpoint of further improving the reflectance, rutile type is preferable. Titanium oxide obtained by a method such as a sulfuric acid method or a chlorine method can be used. The white inorganic pigment may be 1 kind of the single material or a mixture of two or more kinds of the materials. The shape of the white inorganic pigment may be, for example, any of an irregular shape, a crushed shape, a flake shape, or a spherical shape.

Examples of commercially available white inorganic pigments include "PX 3788" made by sakai chemical industry corporation; タイペーク "CR-50", "CR-57", "CR-80", "CR-90", "CR-93", "CR-95", "CR-97", "CR-60", "CR-63", "CR-67", "CR-58", "CR-85", "UT 771", manufactured by Stone Productivity Ltd; デュポン, タイピュア "R-100", "R-101", "R-102", "R-103", "R-104", "R-105", "R-108", "R-900", "R-902", "R-960", "R-706", "R-931"; "AHP 300" manufactured by light metals of Japan; アルナビーズ "CB-P05" and "CB-A30S" manufactured by Showa electrician.

The specific surface area of the white inorganic pigment is preferably 0.5m²A value of 1m or more, more preferably 1 g or more²A specific ratio of 2m or more/g²More than g. The upper limit is not particularly limited and,preferably 80m²70m below/g²Less than g or 60m²The ratio of the carbon atoms to the carbon atoms is less than g. The specific surface area can be obtained as follows: according to the BET method, nitrogen gas was adsorbed to the surface of the sample using a specific surface area measuring apparatus (Macsorb HM-1210, manufactured by マウンテック Co., Ltd.), and the specific surface area was calculated using the BET multipoint method.

From the viewpoint of remarkably obtaining the desired effect of the present invention, the average particle diameter of the white inorganic pigment is preferably 0.01 μm or more, more preferably 0.05 μm or more, and further preferably 0.1 μm or more, and is preferably 10 μm or less, more preferably 5 μm or less, further preferably 2 μm or less, or 1 μm or less.

The average particle diameter of the white inorganic pigment can be determined by a laser diffraction/scattering method based on Mie scattering theory. Specifically, the particle size distribution of the white inorganic pigment is prepared on a volume basis by using a laser diffraction scattering particle size distribution measuring apparatus, and the median particle size is measured as an average particle size. As the measurement sample, a sample obtained by weighing 100mg of a white inorganic pigment and 10g of methyl ethyl ketone in a vial and dispersing them for 10 minutes by ultrasonic waves can be used. For the measurement sample, the wavelength of the light source used was set to blue and red using a laser diffraction type particle size distribution measuring apparatus, the volume-based particle size distribution of the white inorganic pigment was measured by the flow cell method, and the average particle size was calculated as the median particle size from the obtained particle size distribution. Examples of the laser diffraction type particle size distribution measuring apparatus include "LA-960" manufactured by horiba, Inc.

The white inorganic pigment is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. The surface treatment agent may be used alone in 1 kind, or may be used in combination of two or more kinds. Examples of the surface treatment agent include silane coupling agents such as a vinyl silane coupling agent, an epoxy silane coupling agent, a styrene silane coupling agent, (meth) acrylic silane coupling agent, an amino silane coupling agent, an isocyanurate silane coupling agent, a ureide silane coupling agent, a mercapto silane coupling agent, an isocyanate silane coupling agent, an acid anhydride silane coupling agent, an alkyl silane coupling agent, and a phenyl silane coupling agent. In the method of the present invention using a specific curing condition, the surface treatment agent is preferably a surface treatment agent containing no nitrogen atom (containing no nitrogen atom), and more preferably a silane coupling agent containing no nitrogen atom (containing no nitrogen atom), from the viewpoint of easily realizing a light-reflecting substrate exhibiting a higher reflectance and having more excellent base adhesion. Examples of the nitrogen atom-free (nitrogen atom-free) silane coupling agent include silane coupling agents selected from the group consisting of phenyl silane coupling agents, alkyl silane coupling agents, epoxy silane coupling agents, vinyl silane coupling agents, (meth) acrylic silane coupling agents and styrene silane coupling agents.

Examples of the phenylsilane coupling agent include phenyltrimethoxysilane and phenyltriethoxysilane. Examples of the alkylsilane coupling agent include methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1, 6-bis (trimethoxysilyl) hexane, and the like. Examples of the epoxy silane coupling agent include 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane.

Examples of the vinyl silane coupling agent include vinyltrimethoxysilane and vinyltriethoxysilane. Examples of the (meth) acrylic silane coupling agent include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane. Examples of the styrene-based silane coupling agent include p-styryltrimethoxysilane.

Examples of commercially available surface treatment agents include "KBM-103" and "KBE-103" (phenylsilane coupling agents) manufactured by shin-Etsu chemical industries, Ltd.; "KBM-13", "KBM-22", "KBE-13", "KBE-22", "KBM-3033", "KBE-3033", "KBM-3063", "KBE-3083", "KBM-3103C", "KBM-3066", "KBM-7103" (alkylsilane coupling agent); "KBM-1003" and "KBE-1003" (vinyl silane coupling agent); "KBM-303", "KBM-402", "KBM-403", "KBE-402", "KBE-403" (epoxy silane coupling agent); "KBM-1403" (styrene-based silane coupling agent); "KBM-502", "KBM-503", "KBE-502", "KBE-503", "KBM-5103" ((meth) acrylic silane coupling agent), and the like.

From the viewpoint of improving the dispersibility of the white inorganic pigment, the degree of surface treatment with the surface treatment agent preferably falls within a predetermined range. Specifically, 100 parts by mass of the white inorganic pigment is preferably surface-treated with 0.2 to 5 parts by mass of a surface treatment agent, preferably 0.2 to 3 parts by mass, and preferably 0.3 to 2 parts by mass.

The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the white inorganic pigment. From the viewpoint of improving the dispersibility of the white inorganic pigment, the amount of carbon per unit surface area of the white inorganic pigment is preferably 0.02mg/m²Above, more preferably 0.1mg/m²Above, more preferably 0.2mg/m²The above. On the other hand, from the viewpoint of suppressing the rise in melt viscosity of the resin varnish and melt viscosity in the sheet state, it is preferably 1mg/m²Less than, more preferably 0.8mg/m²The concentration is preferably 0.5mg/m or less²The following.

The amount of carbon per unit surface area of the white inorganic pigment can be measured by washing the white inorganic pigment after the surface treatment with a solvent (for example, Methyl Ethyl Ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent was added to the white inorganic pigment surface-treated with the surface treatment agent, and ultrasonic cleaning was performed at 25 ℃ for 5 minutes. After removing the supernatant liquid and drying the solid components, the carbon amount per unit surface area of the white inorganic pigment can be determined using a carbon analyzer. As the carbon analyzer, "EMIA-320V" manufactured by horiba, etc. can be used.

From the viewpoint of realizing a light-reflecting substrate exhibiting high light reflectance, the content of the white inorganic pigment in the resin composition layer is preferably 20% by mass or more, more preferably 22% by mass or more, and further preferably 24% by mass or more, or 25% by mass or more, assuming that the nonvolatile component in the resin composition layer is 100% by mass.

In the prior art, when a resin composition layer having a high content of a white inorganic pigment is used, the obtained light reflective substrate tends to have poor base adhesion, but according to the method of the present invention using specific curing conditions, the content of the white inorganic pigment can be further increased without lowering the base adhesion. For example, the content of the white inorganic pigment in the resin composition layer may be increased to 26 mass% or more, 28 mass% or more, 30 mass% or more, 32 mass% or more, 34 mass% or more, 36 mass% or more, 38 mass% or more, or 40 mass% or more.

From the viewpoint of achieving good substrate adhesion, the upper limit of the content of the white inorganic pigment in the resin composition layer is preferably 70% by mass or less, more preferably 65% by mass or less, and further preferably 60% by mass or less or 55% by mass or less.

In one preferable embodiment, the content of the white inorganic pigment is 20 to 60% by mass, based on 100% by mass of nonvolatile components in the resin composition layer.

Other inorganic filler materials

The resin composition layer may contain other inorganic filler materials under the condition that at least white inorganic pigment is contained. The other inorganic filler is not particularly limited as long as it is an inorganic filler different from the white inorganic pigment, and for example, an inorganic filler having a reflectance of less than 90% with respect to light having a wavelength of 500nm can be used.

Among these, in the method of the present invention using specific curing conditions, silica is suitable as another inorganic filler, from the viewpoint of easily realizing a light-reflecting substrate exhibiting a higher reflectance and having more excellent adhesion to a base. Examples of the silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Further, the silica is preferably spherical silica. The specific surface area and the average particle diameter of silica are the same as those of the white inorganic pigment. The silica may be used alone in 1 kind, or two or more kinds may be used in combination.

Examples of commercially available silica products include "UFP-30" manufactured by デンカ, Inc.; "SP 60-05" and "SP 507-05" manufactured by Nippon iron ケミカル & マテリアル; "YC 100C", "YA 050C", "YA 050C-MJE", "YA 010C" manufactured by アドマテックス; トクヤマ, "シルフィル NSS-3N", "シルフィル NSS-4N" and "シルフィル NSS-5N"; アドマテックス, "SC 2500 SQ", "SO-C4", "SO-C2", and "SO-C1".

From the viewpoint of improving moisture resistance and dispersibility, other inorganic fillers such as silica are preferably treated with a surface treatment agent. Examples of the surface treatment agent include the same ones as those in the white inorganic pigment. The degree of surface treatment with the surface treatment agent of the other inorganic filler is the same as that of the white inorganic pigment.

From the viewpoint of remarkably obtaining the effect of the present invention, the content of the other inorganic filler in the resin composition layer is preferably 1 mass% or more, more preferably 5 mass% or more, further preferably 10 mass% or more, and particularly preferably 15 mass% or more, assuming that the nonvolatile content in the resin composition layer is 100 mass%. The upper limit of the content of the other inorganic filler is preferably 70% by mass or less, more preferably 50% by mass or less, further preferably 40% by mass or less, and particularly preferably 35% by mass or less.

From the viewpoint of realizing a light-reflecting substrate exhibiting high light reflectance and good base adhesion, the total content of the white inorganic pigment and the other inorganic fillers, that is, the total content of the inorganic filler components is preferably 20% by mass or more, more preferably 30% by mass or more, further preferably 40% by mass or more, particularly preferably 50% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, further preferably 75% by mass or less, and particularly preferably 70% by mass or less, assuming that the nonvolatile component in the resin composition layer is 100% by mass.

From the viewpoint of realizing a light reflective substrate exhibiting high light reflectance and good base adhesion, the mass ratio of the other inorganic filler such as silica to the white inorganic pigment (mass of the other inorganic filler/mass of the white inorganic pigment) is preferably 0.1 or more, more preferably 0.2 or more, further preferably 0.5 or more, particularly preferably 0.8 or more, and preferably 4 or less, more preferably 4 or less, further preferably 2 or less, and particularly preferably 1.5 or less.

In the resin composition layer, a thermosetting resin is contained as a resin. As the thermosetting resin, conventionally known thermosetting resins used in forming an insulating layer of a printed wiring board can be used, and among them, epoxy resins are preferable from the viewpoint of easily realizing a light reflective substrate exhibiting higher reflectance and more excellent substrate adhesion in the method of the present invention using a specific curing condition. Thus, in one embodiment, the resin composition comprises a thermosetting resin, and in one suitable embodiment, the thermosetting resin comprises an epoxy resin.

-epoxy resins-

The epoxy resin means a curable resin having an epoxy group. The epoxy resin may be used alone in 1 kind, or two or more kinds may be used in combination.

Examples of the epoxy resin include a bixylenol type epoxy resin, a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a bisphenol AF type epoxy resin, a hydrogenated bisphenol a type epoxy resin, a dicyclopentadiene type epoxy resin, a triphenol type epoxy resin, a naphthol novolac type epoxy resin, a phenol novolac type epoxy resin, a tert-butyl-catechol type epoxy resin, a naphthalene type epoxy resin, a naphthol type epoxy resin, an anthracene type epoxy resin, a glycidylamine type epoxy resin, a glycidyl ester type epoxy resin, a cresol novolac type epoxy resin, a phenol aralkyl type epoxy resin, a biphenyl type epoxy resin, a linear aliphatic epoxy resin, an epoxy resin having a butadiene structure, an alicyclic epoxy resin, a heterocyclic type epoxy resin, an epoxy resin having a spiro ring, a cyclohexane type epoxy resin, Cyclohexane dimethanol type epoxy resin, naphthalene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, isocyanurate type epoxy resin, phenol phthalimidine type epoxy resin, phenolphthalein type epoxy resin, and the like.

In the resin composition layer, the epoxy resin preferably contains an epoxy resin having 2 or more epoxy groups in 1 molecule. The proportion of the epoxy resin having 2 or more epoxy groups in 1 molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more, relative to 100% by mass of the nonvolatile content of the epoxy resin.

The presence in the epoxy resin: an epoxy resin that is solid at a temperature of 25 ℃ (hereinafter also referred to as "solid epoxy resin") and an epoxy resin that is liquid at a temperature of 25 ℃ (hereinafter also referred to as "liquid epoxy resin"). In the resin sheet used in the method of the present invention, the resin composition layer may contain only a solid epoxy resin, only a liquid epoxy resin, or a combination of a solid epoxy resin and a liquid epoxy resin.

The solid epoxy resin is preferably a solid epoxy resin having 3 or more epoxy groups in 1 molecule, and more preferably an aromatic solid epoxy resin having 3 or more epoxy groups in 1 molecule.

The solid epoxy resin is preferably a bixylenol type epoxy resin, a naphthalene type tetrafunctional epoxy resin, a naphthol novolac type epoxy resin, a cresol novolac type epoxy resin, a dicyclopentadiene type epoxy resin, a triphenol type epoxy resin, a naphthol type epoxy resin, a biphenyl type epoxy resin, a naphthalene ether type epoxy resin, an anthracene type epoxy resin, a bisphenol a type epoxy resin, a bisphenol AF type epoxy resin, a phenol aralkyl type epoxy resin, a tetraphenylethane type epoxy resin, a phenol phthalimidine type epoxy resin, or a phenolphthalein type epoxy resin.

Specific examples of the solid epoxy resin include "HP 4032H" (naphthalene type epoxy resin) manufactured by DIC corporation; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resins) manufactured by DIC; "N-690" (cresol novolac type epoxy resin) manufactured by DIC; "N-695" (cresol novolac type epoxy resin) manufactured by DIC; "HP-7200", "HP-7200 HH", "HP-7200H" and "HP-7200L" (dicyclopentadiene type epoxy resins) manufactured by DIC; "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S" and "HP 6000" (naphthalene ether type epoxy resins) manufactured by DIC; EPPN-502H (triphenol type epoxy resin) manufactured by Nippon chemical Co., Ltd.; "NC 7000L" (naphthol novolac type epoxy resin) manufactured by japan chemicals); "NC 3000H", "NC 3000L", "NC 3000 FH" and "NC 3100" (biphenyl type epoxy resin) manufactured by japan chemical company; ESN475V (naphthalene type epoxy resin) manufactured by Nippon iron ケミカル & マテリアル; "ESN 485" (naphthol type epoxy resin) manufactured by Nippon iron ケミカル & マテリアル Co., Ltd.; ESN375 (dihydroxynaphthalene-type epoxy resin) manufactured by Nippon iron ケミカル & マテリアル Co., Ltd.; "YX 4000H", "YX 4000 HK" and "YL 7890" (bixylenol type epoxy resin) manufactured by mitsubishi ケミカル; "YL 6121" (biphenyl type epoxy resin) manufactured by Mitsubishi ケミカル; "YX 8800" (anthracene-based epoxy resin) manufactured by Mitsubishi ケミカル; "YX 7700" (phenol aralkyl type epoxy resin) manufactured by Mitsubishi ケミカル Co., Ltd.; PG-100 and CG-500 manufactured by Osaka ガスケミカル company; "YX 7760" (bisphenol AF type epoxy resin) manufactured by mitsubishi ケミカル corporation; "YL 7800" (fluorene-based epoxy resin) manufactured by Mitsubishi ケミカル; "jER 1010" (bisphenol a type epoxy resin) manufactured by mitsubishi ケミカル; "jER 1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi ケミカル; "WHR 991S" (phenol-phthalimidine type epoxy resin) manufactured by Nippon chemical Co., Ltd. These can be used alone in 1 kind, also can be combined with more than 2 kinds.

The liquid epoxy resin is preferably a liquid epoxy resin having 2 or more epoxy groups in 1 molecule.

The liquid epoxy resin is preferably a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AF type epoxy resin, a hydrogenated bisphenol a type epoxy resin, a naphthalene type epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, a phenol novolac type epoxy resin, an alicyclic epoxy resin having an ester skeleton, a cyclohexane type epoxy resin, a cyclohexane dimethanol type epoxy resin, or an epoxy resin having a butadiene structure.

Specific examples of the liquid epoxy resin include "HP 4032", "HP 4032D" and "HP 4032 SS" (naphthalene type epoxy resin) manufactured by DIC corporation; "828 US", "828 EL", "jER 828 EL" and "825" (bisphenol A epoxy resin) manufactured by Mitsubishi ケミカル; "jER 807" and "1750" (bisphenol F type epoxy resin) manufactured by Mitsubishi ケミカル; "jER 152" (phenol novolac type epoxy resin) manufactured by mitsubishi ケミカル corporation; "630", "630 LSD" and "604" (glycidyl amine type epoxy resins) manufactured by Mitsubishi ケミカル Co., Ltd.; "ED-523T" (a glycyrrhizin-type epoxy resin) manufactured by ADEKA corporation; "EP-3950L" and "EP-3980S" (glycidylamine-type epoxy resins) manufactured by ADEKA; EP-4088S (dicyclopentadiene type epoxy resin) manufactured by ADEKA Co; "ZX 1059" (a mixture of bisphenol A epoxy resin and bisphenol F epoxy resin) manufactured by Nippon iron ケミカル & マテリアル; "EX-721" (glycidyl ester type epoxy resin) manufactured by ナガセケムテックス Co; "セロキサイド 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by ダイセル; ダイセル, "PB-3600", JP-100 "and" JP-200 "each of Japan Caoda (epoxy resins having a butadiene structure); "ZX 1658" and "ZX 1658 GS" (1, 4-glycidylcyclohexane-type epoxy resin) manufactured by Nippon iron ケミカル & マテリアル, and "YX 8000" (hydrogenated bisphenol A-type epoxy resin) manufactured by Mitsubishi ケミカル, and "KF-101" (epoxy-modified silicone resin) manufactured by shin-Etsu chemical Co. These may be used alone in 1 kind, or two or more kinds may be used in combination.

The epoxy resin may be any one of a solid epoxy resin, a liquid epoxy resin, or a combination thereof, and in the method of the present invention using a specific curing condition, the method preferably includes the solid epoxy resin, and particularly preferably includes the combination of the solid epoxy resin and the liquid epoxy resin, from the viewpoint of easily realizing a light reflective substrate that exhibits a higher reflectance and is more excellent in the adhesion to the substrate.

When the solid epoxy resin and the liquid epoxy resin are used in combination as the epoxy resin, the mass ratio thereof (solid epoxy resin: liquid epoxy resin) is preferably 20:1 to 1:20, more preferably 10:1 to 1:10, and particularly preferably 3:1 to 1: 3.

The epoxy equivalent of the epoxy resin is preferably 50g/eq to 5,000g/eq, more preferably 60g/eq to 1,000g/eq, further preferably 80g/eq to 500g/eq, and further preferably 100g/eq to 300g/eq. The epoxy equivalent is the mass of the resin per 1 equivalent of epoxy group. The epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the epoxy resin is preferably 100 to 5,000, more preferably 250 to 3,000, and further preferably 400 to 1,500. The weight average molecular weight of the resin can be measured as a value in terms of polystyrene by a Gel Permeation Chromatography (GPC) method.

From the viewpoint of remarkably obtaining the effect of the present invention, the content of the epoxy resin is preferably 0.5% by mass or more, more preferably 1% by mass or more, further preferably 5% by mass or more, further preferably 10% by mass or more or 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 35% by mass or less, and particularly preferably 30% by mass or less, assuming that the nonvolatile content in the resin composition layer is 100% by mass. Therefore, in one preferable embodiment, the content of the epoxy resin is 1 to 50% by mass, assuming that the nonvolatile content in the resin composition layer is 100% by mass.

In the resin sheet used in the method of the present invention, the resin composition layer may further contain other components. Examples of the other components include a curing agent, a thermoplastic resin, a curing accelerator, and other additives. Hereinafter, each component will be described in detail.

Curing agents

The resin composition layer may contain a curing agent. The curing agent has a function of curing the resin composition by reacting with the epoxy resin. The curing agent may be used alone in 1 kind, or two or more kinds may be used in combination.

The curing agent is not particularly limited, and examples thereof include a phenol curing agent, a carbodiimide curing agent, an acid anhydride curing agent, an amine curing agent, a benzoxazine curing agent, a cyanate ester curing agent, and a thiol curing agent. In the method of the present invention using specific curing conditions, the curing agent preferably contains a phenol-based curing agent from the viewpoint of easily realizing a light-reflecting substrate exhibiting a higher reflectance and more excellent substrate adhesion.

The phenol curing agent is a curing agent having 2 or more phenolic hydroxyl groups in 1 molecule, and examples thereof include a bisphenol curing agent, a biphenyl type phenol curing agent, a naphthalene type phenol curing agent, a phenol novolak type phenol curing agent, a naphthalene ether type phenol curing agent, a phenol curing agent containing a triazine skeleton, a polyphenylene ether type phenol curing agent, a phenol aralkyl type phenol curing agent, a cresol novolak type phenol curing agent, a bisphenol type phenol curing agent, and the like. From the viewpoint of easily realizing a light-reflecting substrate exhibiting a higher reflectance and having more excellent base adhesion, a bisphenol curing agent is preferred, a bisphenol curing agent selected from a bisphenol compound having a fluorine atom, a bisphenol compound having an alicyclic structure, and a bisphenol compound having a fluorene skeleton is more preferred, a bisphenol compound having a fluorine atom is further preferred, and bisphenol AF is particularly preferred.

Specific examples of commercially available phenol-based curing agents include "BIS-AF" and "BIS-Z" manufactured by セントラル Nitrosy, and "BisE" and "BisP-TMC" manufactured by chemical industries, Japan; "BisA", "BisF", "BisP-M" manufactured by Mitsui Chemicals ファイン, Inc.; "BisP-AP", "BisP-MIBK", "BisP-B", "Bis-Z", "BisP-CP", "o, o' -BPF", "BisP-IOTD", "BisP-IBTD", "BisP-DED", "BisP-BA" manufactured by this State chemical industry Co., Ltd; "Bis-C", "Bis 26X-A", "BisOPP-A", "BisOTBP-A", "BisOCHP-A", "BisOFP-A", "BisOC-Z", "BisOC-FL", "BisOFP-A", "BisOC-CP", "BisOCHP-Z", "methylenebis P-CR", "TM-BPF", "BisOC-F", "Bis 3M 6B-IBTD", "BisOC-IST", "BisP-PRM", "BisP-LV", and the like manufactured by this State chemical industry Co.

The carbodiimide-based curing agent is a curing agent having 2 or more carbodiimide structures in 1 molecule, and examples thereof include aliphatic bis-carbodiimides such as tetramethylene-bis (t-butylcarbodiimide) and cyclohexane-bis (methylene-t-butylcarbodiimide); a bis-carbodiimide such as an aromatic bis-carbodiimide such as phenylene-bis (xylylcarbodiimide); aliphatic polycarbodiimides such as polyhexamethylene carbodiimide, polytrimethylhexamethylene carbodiimide, polycyclohexylene carbodiimide, poly (methylenedicyclohexylcarbodiimide), and poly (isophorone carbodiimide); polycarbodiimides such as aromatic polycarbodiimides including poly (phenylene carbodiimide), poly (naphthylene carbodiimide), poly (toluene carbodiimide), poly (methyldiisopropylphenylene carbodiimide), poly (triethylphenylene carbodiimide), poly (diethylphenylene carbodiimide), poly (triisopropylphenylene carbodiimide), poly (diisopropylphenylene carbodiimide), poly (xylylene carbodiimide), poly (tetramethylxylylene carbodiimide), poly (methylenediphenylene carbodiimide), and poly [ methylenebis (methylphenylene) carbodiimide ].

Commercially available carbodiimide-based curing agents include, for example, "カルボジライト V-02B", "カルボジライト V-03", "カルボジライト V-04K", "カルボジライト V-07" and "カルボジライト V-09" manufactured by Nisshinbo ケミカル; ラインケミー, "スタバクゾール P", "スタバクゾール P400" and "ハイカジル 510".

The acid anhydride curing agent is a curing agent having 1 or more carboxylic anhydride groups (-CO-O-CO-) in 1 molecule, and examples thereof include aromatic acid anhydride curing agents such as phthalic anhydride, pyromellitic dianhydride, 1,4,5, 8-naphthalene tetracarboxylic dianhydride, 2,3,6, 7-naphthalene tetracarboxylic dianhydride, 3 ', 4,4 ' -benzophenone tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3 ', 4,4 ' -diphenylsulfone tetracarboxylic dianhydride, 3 ', 4,4 ' -diphenyl ether tetracarboxylic dianhydride, 3 ', 4,4 ' -biphenyl tetracarboxylic dianhydride, and methylene-4, 4 ' -biphthalic dianhydride; aliphatic acid anhydride-based curing agents such as tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, cyclopentanetetracarboxylic dianhydride, and cyclohexane-1, 2,4, 5-tetracarboxylic dianhydride; and polymer anhydride-based curing agents such as styrene/maleic anhydride copolymers and alkyl (meth) acrylate/styrene/maleic anhydride copolymers. Examples of commercially available acid anhydride curing agents include "HNA-100", "MH-700", "MTA-15", "DDSA", "OSA", and "YH-306", "YH-307" manufactured by Mitsubishi ケミカル, and "HN-2200" and "HN-5500" manufactured by Hitachi chemical Co., Ltd.

The amine-based curing agent is a curing agent having 2 or more amino groups, and examples thereof include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, and the like, and among them, aromatic amines are preferable from the viewpoint of exhibiting the desired effect of the present invention. The amine-based curing agent is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of the amine-based curing agent include 4,4 '-methylenebis (2, 6-dimethylaniline), 4' -diaminodiphenylmethane, 4 '-diaminodiphenylsulfone, 3' -diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4 '-diaminodiphenyl ether, 3' -dimethyl-4, 4 '-diaminobiphenyl, 2' -dimethyl-4, 4 '-diaminobiphenyl, 3' -dihydroxybenzidine, 2-bis (3-amino-4-hydroxyphenyl) propane, 3-dimethyl-5, 5-diethyl-4, 4-diphenylmethanediamine, 2-bis (4-aminophenyl) propane, and the like, 2, 2-bis (4- (4-aminophenoxy) phenyl) propane, 1, 3-bis (3-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, 1, 4-bis (4-aminophenoxy) benzene, 4' -bis (4-aminophenoxy) biphenyl, bis (4- (4-aminophenoxy) phenyl) sulfone, bis (4- (3-aminophenoxy) phenyl) sulfone and the like. As the amine-based curing agent, commercially available ones can be used, and examples thereof include "SEIKACURE-S" manufactured by セイカ, and "KAYABOND C-200S", "KAYABOND C-100", "カヤハード A-A", "カヤハード A-B", "カヤハード A-S", and "エピキュア W" manufactured by Mitsubishi ケミカル, and the like.

Specific examples of the benzoxazine-based curing agent include "JBZ-OP 100D" and "ODA-BOZ" manufactured by JFE ケミカル; "HFB 2006M" available from Showa Polymer Co; "P-d" and "F-a" manufactured by four national chemical industries, Inc.

Examples of the cyanate ester curing agent include bisphenol A dicyanate, polyphenolic cyanate (oligo (3-methylene-1, 5-phenylene cyanate)), 4 '-methylenebis (2, 6-dimethylphenylcyanate), 4' -ethylidenediphenyldicyanate, hexafluorobisphenol A dicyanate, difunctional cyanate ester resins such as 2, 2-bis (4-cyanate) phenylpropane, 1-bis (4-cyanatophenylmethane), bis (4-cyanate-3, 5-dimethylphenyl) methane, 1, 3-bis (4-cyanatophenyl-1- (methylethylidene)) benzene, bis (4-cyanatophenyl) sulfide, and bis (4-cyanatophenyl) ether; polyfunctional cyanate ester resins derived from phenol novolak, cresol novolak and the like; prepolymers obtained by partially triazinating these cyanate ester resins, and the like. Specific examples of the cyanate-based curing agent include "PT 30" and "PT 60" (both of which are phenol novolac type polyfunctional cyanate ester resins) manufactured by ロンザジャパン, and "BA 230" and "BA 230S 75" (prepolymers in which a part or all of bisphenol a dicyanate ester is triazinized to form a trimer).

The thiol curing agent is a curing agent having 2 or more mercapto groups, and examples thereof include trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), tris (3-mercaptopropyl) isocyanurate, and the like.

The equivalent weight of the reactive group of the curing agent is preferably 50g/eq to 3000g/eq, more preferably 100g/eq to 1000g/eq, further preferably 100g/eq to 500g/eq, and particularly preferably 100g/eq to 300g/eq. The reactive group equivalent is the mass of the curing agent per 1 equivalent of the reactive group. The reactive group is, for example, a phenolic hydroxyl group when it is a phenolic curing agent. In the case of an acid anhydride-based curing agent, 1 equivalent of a carboxylic anhydride group (-CO-O-CO-) corresponds to 2 equivalents of the reactive group.

From the viewpoint of remarkably obtaining the effect of the present invention, the content of the curing agent is preferably 30% by mass or less, more preferably 20% by mass or less, further preferably 15% by mass or less, particularly preferably 10% by mass or less, for example, 0% by mass or more, 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, further preferably 1% by mass or more, and particularly preferably 3% by mass or more, assuming that the nonvolatile component in the resin composition layer is 100% by mass.

Thermoplastic resins

The resin composition layer may contain a thermoplastic resin. The thermoplastic resin may be used alone in 1 kind, or two or more kinds may be used in combination.

Examples of the thermoplastic resin include phenoxy resins, polyvinyl acetal resins, acrylic resins, polyolefin resins, polybutadiene resins, polyimide resins, polyamideimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polyetherimide resins, polycarbonate resins, polyetheretherketone resins, and polyester resins, and among them, preferred are resins selected from phenoxy resins, acrylic resins, and polyphenylene ether resins.

Examples of the phenoxy resin include phenoxy resins having 1 or more kinds of skeletons selected from a bisphenol a skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a bisphenol acetophenone skeleton, a novolac skeleton, a biphenyl skeleton, a fluorene skeleton, a dicyclopentadiene skeleton, a norbornene skeleton, a naphthalene skeleton, an anthracene skeleton, an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton. The end of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. The phenoxy resin may be used alone in 1 kind, or two or more kinds may be used in combination. Specific examples of the phenoxy resin include "1256" and "4250" (both phenoxy resins having a bisphenol a skeleton) manufactured by mitsubishi ケミカル, "YX 8100" (phenoxy resin having a bisphenol S skeleton) and "YX 6954" (phenoxy resin having a bisphenol acetophenone skeleton), "FX 280" and "FX 293" manufactured by mitsubishi ケミカル & マテリアル, "YX 7200B 35", "YL 7500BH 30", "YX 6954BH 30", "YX 7553BH 30", "YL 7769BH 30", "YL 6794", "YL 7213", "YL 7290" and "YL 7482" manufactured by mitsubishi ケミカル.

Examples of the polyvinyl acetal resin include polyvinyl formal resins and polyvinyl butyral resins, and polyvinyl butyral resins are preferred. Specific examples of the polyvinyl acetal resin include "electrochemical ブチラール 4000-2", "electrochemical ブチラール 5000-A", "electrochemical ブチラール 6000-C", "electrochemical ブチラール 6000-EP" manufactured by electrochemical industries, エスレック BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series manufactured by hydrochemical industries.

The acrylic resin is a polymer obtained by polymerizing a monomer component including a (meth) acrylate monomer. The monomer component constituting the acrylic resin may contain, as a copolymerization component, a (meth) acrylamide monomer, a styrene monomer, a functional group-containing monomer, and the like in addition to the (meth) acrylate monomer. Specific examples of the acrylic resin include "ARUFONUP-1000", "ARUFONUP-1010", "ARUFONUP-1020", "ARUFONUP-1021", "ARUFONUP-1061", "ARUFONUP-1080", "ARUFONUP-1110", "ARUFONUP-1170", "ARUFONUP-1190", "ARUFONUP-1500", "ARUFONUH-2000", "ARUFONUP-2041", "ARUFONUH-2190", "ARUFONUHE-2012", "ARUFONUC-3510", "ARUFONUG 401-0", "ARUFONUS-6100" and "ARUFUS-6170" manufactured by Tokya synthetic company. These may be used alone in 1 kind, or two or more kinds may be used in combination.

Examples of the polyolefin resin include ethylene copolymer resins such as low density polyethylene, ultra-low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer; polyolefin elastomers such as polypropylene and ethylene-propylene block copolymers.

Examples of the polybutadiene resin include resins having a hydrogenated polybutadiene skeleton, polybutadiene resins having hydroxyl groups, polybutadiene resins having phenolic hydroxyl groups, polybutadiene resins having carboxyl groups, polybutadiene resins having acid anhydride groups, polybutadiene resins having epoxy groups, polybutadiene resins having isocyanate groups, polybutadiene resins having urethane groups, and polyphenylene ether-polybutadiene resins.

Specific examples of the polyimide resin include "リカコート SN 20" and "リカコート PN 20" manufactured by New Japan chemical and chemical Co. Specific examples of the polyimide resin include linear polyimides obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (polyimides described in jp 2006-a 37083); modified polyimides such as polyimides containing a polysiloxane skeleton (described in Japanese patent laid-open Nos. 2002-12667 and 2000-319386).

Specific examples of the polyamideimide resin include "バイロマックス HR11 NN" and "バイロマックス HR16 NN" manufactured by toyobo seika corporation. Specific examples of the polyamide-imide resin include modified polyamide-imides such as "KS 9100" and "KS 9300" (polyamide-imide having a polysiloxane skeleton) manufactured by hitachi chemical industry.

Specific examples of the polyether sulfone resin include "PES 5003P" manufactured by sumitomo chemical corporation.

Specific examples of polysulfone resins include polysulfone "P1700" and polysulfone "P3500" manufactured by ソルベイアドバンストポリマーズ.

Specific examples of the polyphenylene ether resin include an oligophenylene ether-styrene resin "OPE-2 St 1200" or "OPE-2 St 2200" manufactured by Mitsubishi gas chemical corporation, and "Noryl (registered trademark) SA 90" manufactured by SABIC corporation. Specific examples of the polyetherimide resin include "ウルテム" manufactured by GE corporation.

Examples of the polycarbonate resin include a hydroxyl group-containing carbonate resin, a phenolic hydroxyl group-containing carbonate resin, a carboxyl group-containing carbonate resin, an anhydride group-containing carbonate resin, an isocyanate group-containing carbonate resin, and a carbamate group-containing carbonate resin. Specific examples of the polycarbonate resin include "FPC 0220" manufactured by Mitsubishi gas chemical company, "T6002" and "T6001" (polycarbonate diol) manufactured by Asahi Kasei ケミカルズ company, "C-1090", "C-2090" and "C-3090" (polycarbonate diol) manufactured by クラレ company. Specific examples of the polyether ether ketone resin include "スミプロイ K" manufactured by Sumitomo chemical Co. Examples of the polyester resin include polyethylene terephthalate resins.

The weight average molecular weight of the thermoplastic resin is preferably 8,000 or more, more preferably 10,000 or more, further preferably 20,000 or more, and preferably 100,000 or less, more preferably 70,000 or less, further preferably 60,000 or less. The weight average molecular weight of the resin can be measured as a value in terms of polystyrene by a Gel Permeation Chromatography (GPC) method.

The thermoplastic resin preferably has a transmittance of 80% or more in a direction perpendicular to a light having a wavelength of 450nm incident on the film surface when the film is formed to have a thickness of 20 μm.

The content of the thermoplastic resin is preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, and particularly preferably 25% by mass or less, for example, 0% by mass or more, 0.1% by mass or more, preferably 1% by mass or more, more preferably 5% by mass or more, and particularly preferably 10% by mass or more, assuming that the nonvolatile content in the resin composition layer is 100% by mass.

Curing accelerators

The resin composition layer may contain a curing accelerator. The curing accelerator has a function of accelerating a curing reaction of the thermosetting resin. The curing accelerator may be used alone in 1 kind, or two or more kinds may be used in combination.

Examples of the curing accelerator include phosphorus-based curing accelerators, imidazole-based curing accelerators, amine-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators. Among these, as the curing accelerator, a phosphorus-based curing accelerator and an imidazole-based curing accelerator are preferable from the viewpoint of achieving higher light reflectance, and a phosphorus-based curing accelerator is more preferable.

The phosphorus-based curing accelerator preferably contains 1 or more kinds selected from among phosphonium salts and phosphines from the viewpoint of achieving higher light reflectance.

Examples of the phosphonium salt include aliphatic phosphonium salts such as tetrabutylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium acetate, tetrabutylphosphonium caprate, tetrabutylphosphonium laurate, bis (tetrabutylphosphonium) pyromellitate, tetrabutylphosphonium hexahydrophthalate, tetrabutylphosphonium-2, 6-bis [ (2-hydroxy-5-methylphenyl) methyl ] -4-methylphenoxide, di-t-butylmethylphosphonium tetraphenylborate and the like; onium salts such as methyl triphenyl phosphonium bromide, ethyl triphenyl phosphonium bromide, propyl triphenyl phosphonium bromide, butyl triphenyl phosphonium bromide, benzyl triphenyl phosphonium chloride, tetraphenyl phosphonium bromide, p-tolyl triphenyl phosphonium tetra-p-tolyl borate, tetraphenyl phosphonium tetraphenyl borate, tetraphenyl phosphonium tetra-p-tolyl borate, triphenylethyl phosphonium tetraphenyl borate, tris (3-methylphenyl) ethyl phosphonium tetraphenyl borate, tris (2-methoxyphenyl) ethyl phosphonium tetraphenyl borate, (4-methylphenyl) triphenyl phosphonium thiocyanate, tetraphenyl phosphonium thiocyanate, butyl triphenyl phosphonium thiocyanate and the like.

Examples of the phosphine include aliphatic phosphines such as tributylphosphine, tri-tert-butylphosphine, trioctylphosphine, di-tert-butyl (2-butenyl) phosphine, di-tert-butyl (3-methyl-2-butenyl) phosphine, and tricyclohexylphosphine; dibutylphenylphosphine, di-t-butylphenyl phosphine, methyldiphenylphosphine, ethyldiphenylphosphine, butyldiphenylphosphine, diphenylcyclohexylphosphine, triphenylphosphine, tri-o-tolylphosphine, tri-m-tolylphosphine, tri-p-tolylphosphine, tri (4-ethylphenyl) phosphine, tri (4-propylphenyl) phosphine, tri (4-isopropylphenyl) phosphine, tri (4-butylphenyl) phosphine, tri (4-t-butylphenyl) phosphine, tri (2, 4-dimethylphenyl) phosphine, tri (2, 5-dimethylphenyl) phosphine, tri (2, 6-dimethylphenyl) phosphine, tri (3, 5-dimethylphenyl) phosphine, tri (2,4, 6-trimethylphenyl) phosphine, tri (2, 6-dimethyl-4-ethoxyphenyl) phosphine, tri (2-methoxyphenyl) phosphine, triphenylphosphine, tri (4-t-butylphenyl) phosphine, tri (4-methylphenyl) phosphine, tri (4-methoxyphenyl) phosphine, tri (4-methylphenyl) phosphine, tri (4-phenyl) phosphine, tri (4-methylphenyl) phosphine, tri (4-butyl-phenyl) phosphine, tri (4-phenyl) phosphine, tri (2-phenyl) phosphine, tri (4, tri (2-phenyl) phosphine, tri (4, tri (2-butyl-phenyl) phosphine, tri (2-butyl, tri (4, tri (2-phenyl) phosphine, tri (4, tri-phenyl) phosphine, tri (2-butyl, tri (4, tri-phenyl) phosphine, tri (2-phenyl) phosphine, tri (, Aromatic phosphines such as tris (4-methoxyphenyl) phosphine, tris (4-ethoxyphenyl) phosphine, tris (4-tert-butoxyphenyl) phosphine, diphenyl-2-pyridylphosphine, 1, 2-bis (diphenylphosphino) ethane, 1, 3-bis (diphenylphosphino) propane, 1, 4-bis (diphenylphosphino) butane, 1, 2-bis (diphenylphosphino) acetylene, and 2, 2' -bis (diphenylphosphino) diphenyl ether; aromatic phosphine-borane complexes such as triphenylphosphine-triphenylborane; and aromatic phosphine-quinone addition reaction products such as triphenylphosphine-p-benzoquinone addition reaction products.

As the phosphorus-based curing accelerator, commercially available products such as "TBP-DA" manufactured by Beixing chemical industry Co., Ltd. can be used.

Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1, 2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-heptadecylimidazole, 1, 2-dimethylimidazole, 2-ethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-cyanoethyl-2-methylimidazole, 2-decylimidazole, 2-ethylimidazole, 2-decylimidazole, 2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 2-decylimidazole, and mixtures thereof, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-diamino-6- [2 ' -methylimidazolyl- (1 ') ] -ethyl-s-triazine, 2, 4-diamino-6- [2 ' -undecylimidazolyl- (1 ') ] -ethyl-s-triazine, 2, 4-diamino-6- [2 ' -ethyl-4 ' -methylimidazolyl- (1 ') ] -ethyl-s-triazine, 2, 4-diamino-6- [2 ' -methylimidazolyl- (1 ') ] -ethyl-s-triazine isocyanuric acid adduct, and mixtures thereof, Imidazole compounds such as 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4, 5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2, 3-dihydro-1H-pyrrolo [1,2-a ] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline and 2-phenylimidazoline, and adducts of imidazole compounds with epoxy resins, preferably 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole.

As the imidazole-based curing accelerator, commercially available products such as "P200-H50" manufactured by Mitsubishi ケミカル company and "1B 2 PZ-10M" manufactured by four nationwide chemical companies can be used.

Examples of the amine-based curing accelerator include trialkylamines such as triethylamine and tributylamine; 4-dimethylaminopyridine, benzyldimethylamine, 2,4, 6-tris (dimethylaminomethyl) phenol, 1, 8-diazabicyclo (5,4,0) -undecene, and the like, preferably 4-dimethylaminopyridine, 1, 8-diazabicyclo (5,4,0) -undecene.

Examples of the guanidine-based curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1- (o-tolyl) guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5, 7-triazabicyclo [4.4.0] dec-5-ene, 7-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1-dimethylbiguanide, 1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, 1- (o-tolyl) biguanide and the like, dicyandiamide, 1,5, 7-triazabicyclo [4.4.0] dec-5-ene are preferred.

Examples of the metal-based curing accelerator include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of the organic metal complex include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate; organic copper complexes such as copper (II) acetylacetonate; organic zinc complexes such as zinc (II) acetylacetonate; organic iron complexes such as iron (III) acetylacetonate; organic nickel complexes such as nickel (II) acetylacetonate; and organic manganese complexes such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

From the viewpoint of remarkably obtaining the effect of the present invention, the content of the curing accelerator is preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 1% by mass or less, particularly preferably 0.8% by mass or less, for example, 0% by mass or more, 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and particularly preferably 0.1% by mass or more, assuming that the nonvolatile component in the resin composition layer is 100% by mass.

Other additives

The resin composition layer may further contain other additives. Examples of the other additives include photocurable components such as (meth) acrylic resins and radical polymerizable compounds, and diluents and photopolymerization initiators as auxiliaries therefor; organic fillers such as rubber particles; leveling agents such as silicone leveling agents and acrylic polymer leveling agents; thickeners such as bentonite and montmorillonite; defoaming agents such as silicone defoaming agents, acrylic defoaming agents, fluorine defoaming agents, and vinyl resin defoaming agents; ultraviolet absorbers such as benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers and salicylic acid-based ultraviolet absorbers; adhesion improvers such as urea silane; adhesion imparting agents such as triazole-based adhesion imparting agents, tetrazole-based adhesion imparting agents, and triazine-based adhesion imparting agents; antioxidants such as hindered phenol antioxidants; fluorescent whitening agents such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, and red phosphorus), nitrogen flame retardants (e.g., melamine sulfate), halogen flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate dispersants, polyoxyalkylene dispersants, acetylene dispersants, silicone dispersants, anionic dispersants, and cationic dispersants; and stabilizers such as borate stabilizers, titanate stabilizers, aluminate stabilizers, zirconate stabilizers, isocyanate stabilizers, carboxylic acid stabilizers, and carboxylic acid anhydride stabilizers. The other additives may be used alone in an amount of 1, or in combination in an amount of 2 or more in any ratio. The content of other additives can be appropriately set if it is a person skilled in the art.

From the viewpoint of thinning of the light reflective substrate, the thickness of the resin composition layer is preferably 200 μm or less, more preferably 150 μm or less or 100 μm or less, and further preferably 80 μm or less, 60 μm or less or 50 μm or less, from the viewpoint that the light reflective substrate produced by the method of the present invention is excellent in light reflectance even when the reflective sheet (cured body of the resin composition layer) is a thin film. The lower limit of the thickness of the resin composition layer is not particularly limited, and may be usually 10 μm or more, 15 μm or more, 20 μm or more, or the like.

In the method of the present invention using the specific curing conditions, the minimum melt viscosity of the resin composition layer is preferably 5000 poise or less, more preferably 2000 poise or less, still more preferably 1000 poise or less, and particularly preferably 500 poise or less, from the viewpoint of easily realizing a light-reflective substrate exhibiting a higher reflectance and having more excellent base adhesion.

Support-

Examples of the support include a film made of a plastic material, a metal foil, and a release paper, and preferably a film made of a plastic material and a metal foil.

When a film made of a plastic material is used as the support, examples of the plastic material include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); acrylic acids such as Polycarbonate (PC) and polymethyl methacrylate (PMMA); cyclic polyolefin, cellulose Triacetate (TAC), polyether sulfide (PES), polyether ketone, polyimide, and the like. Among these, polyethylene terephthalate and polyethylene naphthalate are preferable, and particularly, inexpensive polyethylene terephthalate is preferable.

When a metal foil is used as the support, examples of the metal foil include a copper foil and an aluminum foil, and a copper foil is preferable. As the copper foil, a foil formed of a simple metal of copper may be used, and a foil formed of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, or the like) may also be used.

The surface of the support to be bonded to the resin composition layer may be subjected to matting treatment, corona treatment, or antistatic treatment.

As the support, a support with a release layer having a release layer on the surface bonded to the resin composition layer can be used. Examples of the release agent used for the release layer of the support with a release layer include 1 or more release agents selected from alkyd resins, polyolefin resins, urethane resins, and silicone resins. As the support with a release layer, commercially available products can be used, and examples thereof include PET films having a release layer containing an alkyd resin-based release agent as a main component, "PET 501010", "SK-1", "AL-5", "AL-7", manufactured by リンテック; ルミラー T60 manufactured by east レ Co; "ピューレックス" by Imperial corporation; ユニチカ, "ユニピール" manufactured by the same company.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When a support with a release layer is used, the thickness of the entire support with a release layer is preferably in the above range.

As the support, a metal foil with a support base, in which a releasable support base is bonded to a thin metal foil, may be used. In one embodiment, a metal foil with a supporting substrate comprises: the adhesive sheet includes a support substrate, a peeling layer provided on the support substrate, and a metal foil provided on the peeling layer. When a metal foil with a support base is used as the support, the resin composition layer is provided on the metal foil.

In the metal foil with a support base, the material of the support base is not particularly limited, and examples thereof include copper foil, aluminum foil, stainless steel foil, titanium foil, and copper alloy foil. When a copper foil is used as the supporting base material, an electrolytic copper foil or a rolled copper foil may be used. The release layer is not particularly limited as long as the metal foil can be released from the support substrate, and examples thereof include an alloy layer of an element selected from Cr, Ni, Co, Fe, Mo, Ti, W, and P; organic coatings, and the like.

As the material of the metal foil with the supporting base material, for example, copper foil or copper alloy foil is preferable.

In the metal foil with a supporting base, the thickness of the supporting base is not particularly limited, but is preferably in the range of 10 to 150 μm, and more preferably in the range of 10 to 100 μm. The thickness of the metal foil may be, for example, in the range of 0.1 μm to 10 μm.

In one embodiment, the resin sheet may further comprise other layers as desired. Examples of the other layer include a protective film provided on a surface of the resin composition layer not bonded to the support (i.e., a surface opposite to the support) and formed by the support. The thickness of the protective film is not particularly limited, and is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dirt or the like on the surface of the resin composition layer and scratches can be suppressed.

The resin sheet can be produced as follows: for example, a liquid resin composition is used as it is or a resin varnish in which a resin composition is dissolved in an organic solvent is prepared, and the resin composition is applied to a support using a die coater or the like and dried to form a resin composition layer.

As the organic solvent, a known solvent can be suitably used, and the kind thereof is not particularly limited. Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ -butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1, 4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; ether ester solvents such as 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol ethyl acetate, γ -butyrolactone, and methyl methoxypropionate; ester alcohol solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. The organic solvent may be used alone in 1 kind, or two or more kinds may be used in combination at an arbitrary ratio.

The drying can be carried out by a known method such as heating or blowing hot air. The drying conditions are not particularly limited, and the resin composition layer is dried so that the content of the organic solvent in the resin composition layer is 10 mass% or less, preferably 5 mass% or less. Although the boiling point of the organic solvent in the resin composition (resin varnish) varies, when a resin composition (resin varnish) containing 30 to 60 mass% of the organic solvent is used, for example, the resin composition layer can be formed by drying at 50 to 150 ℃ for 3 to 10 minutes.

The resin sheet can be wound into a roll and stored. When the resin sheet has a protective film, the protective film may be peeled off for use.

Hereinafter, a method for manufacturing a light reflective substrate according to the present invention (hereinafter, also simply referred to as "the method of the present invention") will be described in detail with reference to preferred embodiments thereof. The present invention is not limited to the embodiments described below, and can be implemented by arbitrarily changing the embodiments without departing from the scope and the equivalent scope of the claims of the present invention.

[ method for producing light-reflecting substrate ]

The method for manufacturing a light-reflecting substrate of the present invention includes the following steps (a) and (B) in this order.

(A) Laminating a resin sheet comprising a support and a resin composition layer containing a white inorganic pigment provided on the support on a substrate having a conductor layer on at least a part of the surface thereof, such that the resin composition layer is bonded to the conductor layer of the substrate;

In the present invention, the phrase "sequentially including" in the steps (a) and (B) means that: the inclusion of other steps is not hindered as long as the steps (a) and (B) are included and are performed in sequence.

Hereinafter, the same applies to "including in sequence" in the process or treatment.

Process (A) -

In the step (a), a resin sheet including a support and a resin composition layer containing a white inorganic pigment provided on the support is laminated on a substrate having a conductor layer on at least a part of a surface thereof, so that the resin composition layer is bonded to the conductor layer of the substrate.

The resin sheet is constructed as described above.

The substrate used in the step (a) is not particularly limited as long as it has a conductive layer on at least a part of the surface thereof, and examples thereof include substrates having a conductive layer formed on one surface or both surfaces thereof, such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. In addition, the conductor layer may be patterned. A substrate having a conductive layer (circuit) formed on one surface or both surfaces of the substrate is sometimes referred to as an "inner layer circuit substrate". In addition, in manufacturing a printed circuit board (light reflecting substrate), the "substrate" referred to in the present invention also includes an intermediate manufactured article in which an insulating layer and/or a conductor layer is further formed. When the light reflection substrate is a component-embedded circuit board, a component-embedded circuit board may be used.

In the present invention, the object to be laminated with a resin sheet in the step (a), that is, the substrate having a conductor layer on at least a part of the surface thereof, is also simply referred to as "base substrate".

The lamination of the substrate and the resin sheet can be performed, for example, by heat-pressing the resin sheet to the substrate from the support side. Examples of the member for heat-pressure bonding the resin sheet to the substrate (hereinafter also referred to as "heat-pressure bonded member") include a heated metal plate (such as an SUS cover) and a metal roll (SUS roll). It is preferable that the resin sheet is pressed through an elastic material such as a heat-resistant rubber so that the resin sheet sufficiently follows the surface irregularities of the substrate, instead of directly pressing the heat-pressure bonding member to the resin sheet.

The lamination of the substrate and the resin sheet may be performed by a vacuum lamination method. In the vacuum lamination method, the heating and crimping temperature is preferably 60-160 ℃, more preferably 80-140 ℃, the heating and crimping pressure is preferably 0.098-1.77 MPa, more preferably 0.29-1.47 MPa, and the heating and crimping time is preferably 20-400 seconds, more preferably 30-300 seconds. The lamination is preferably performed under a reduced pressure of 26.7hPa or less.

The lamination can be performed by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include vacuum pressure laminators manufactured by Nippon Kasei corporation, vacuum applicators manufactured by ニッコー Seedunculture マテリアルズ corporation, and batch vacuum pressure laminators.

The smoothing treatment of the laminated resin sheet can be performed by, for example, pressurizing the heat-pressure bonding member from the support side under normal pressure (atmospheric pressure) after the lamination. The pressing conditions for the smoothing treatment may be the same as the above-described conditions for the heat and pressure bonding of the laminate. The smoothing treatment can be performed using a commercially available laminator. The lamination and smoothing processes may be continuously performed using a commercially available vacuum laminator as described above.

The support may be peeled (removed) between the steps (a) and (B), or may be peeled after the step (B). In the method of the present invention using specific curing conditions, it is preferable to peel the support between the steps (a) and (B) from the viewpoint of easily realizing a light-reflective substrate exhibiting a higher reflectance and having more excellent adhesion to the base. Therefore, in one preferred embodiment, the support is peeled between the steps (a) and (B).

When a reflective sheet (cured body) formed by curing a resin composition layer is used as an interlayer insulating layer and a metal foil is used as a support, the metal foil can be used to form a conductor layer without peeling the support. When a metal foil with a support base is used as the support, the support base (and the release layer) may be peeled off. Also, a metal foil may be used to form the conductor layer.

A process (B)

In the step (B), the resin composition layer is thermally cured. This enables the reflective sheet (cured body) to be formed on the base substrate.

In order to realize a light reflective substrate having good base adhesion, it is important to: the resin composition layer is thermally cured under conditions satisfying at least one of the following (i) and (ii).

(i) At a temperature T₁After the heat treatment for holding, the temperature is controlled at a specific temperature T₁High temperature T₂Heat treatment by holding

According to the method of the present invention using the specific curing conditions, a light-reflecting substrate exhibiting high reflectance and excellent adhesion to the base can be realized. The present inventors have examined the composition of a cured product formed from a resin composition layer for a light-reflecting substrate produced by the method of the present invention, and have confirmed that: a phase rich in the inorganic filler component exists on the surface on the side not in contact with the base substrate, but the proportion of the inorganic filler component decreases at a position at a distance from the surface in the thickness direction. Here, the "thickness direction" refers to the thickness direction of the cured body, and indicates a direction perpendicular to the main surface of the cured body.

It can be presumed that: by the presence of the phase rich in the inorganic filler component in a limited region in the vicinity of the surface on the side not in contact with the base substrate, a significantly higher light reflectance is achieved than the effect expected for the bulk inorganic filler concentration, and by the presence of the phase rich in the resin component in the region in the vicinity of the main surface in contact with the base substrate, excellent adhesion to the base substrate can be exhibited.

Thermal curing conditions (i) -

The thermal curing of the resin composition layer under the condition satisfying (i) is sometimes referred to as "step curing", and is sometimes referred to as "curing at temperature T₁The heat treatment for the subsequent holding is called "precuring" and will be at a specific temperature T₁High temperature T₂The heat treatment for holding is referred to as "post-curing".

Regarding the heat curing condition (i), the temperature T1 also depends on the composition of the resin composition layer, and may be set generally to 50 ℃ C. ltoreq. T₁<T is more than or equal to 60 ℃ and preferably is more than or equal to 150 DEG C₁140 ℃ or lower, more preferably 70 ℃ or lower₁130 ℃ or lower, and further preferably 80 ℃ or lower₁Less than or equal to 120 ℃, particularly preferably less than or equal to 80 ℃ T₁≤110℃。

At a temperature T₁The time for which the hold is performed also depends on the temperature T₁The value of (b) is preferably 10 to 150 minutes, more preferably 15 to 120 minutes, and further preferably 20 to 120 minutes.

At a temperature T₁The heating treatment for holding under the above conditions may be performed under normal pressure or under reduced pressure, and from the viewpoint of easily realizing a light-reflecting substrate exhibiting a higher reflectance and having more excellent adhesion to the base, it is preferable that: the air pressure is preferably in the range of 0.075mmHg to 3751mmHg (0.1hPa to 5000hPa), and more preferably in the range of 1mmHg to 1875mmHg (1.3hPa to 2500 hPa).

Temperature T₂Also depending on the composition of the resin composition layer, T may be usually set to 150 ℃ C. or less₂Less than or equal to 250 ℃, preferably less than or equal to 155 ℃ and less than or equal to T₂230 ℃ or lower, more preferably 160 ℃ or lower₂Less than or equal to 220 ℃, and further preferably less than or equal to 170 DEG C₂210 ℃ or lower, particularly preferably 180 ℃ or lower₂≤200℃。

Note that, the temperature T₁And temperature T₂Preferably satisfies the T value of 20 ℃ ≦ T₂-T₁T is not less than 150 ℃, more preferably not less than 30 ℃ ≦ T₂-T₁140 ℃ or lower, and further preferably 40 ℃ or lower₂-T₁130 ℃ or lower, particularly preferably 50 ℃ or lower T₂-T₁The temperature is less than or equal to 120 ℃.

At a temperature T₂The time for which the hold is performed also depends on the temperature T₂The value of (b) is preferably 10 to 150 minutes, more preferably 15 to 120 minutes, and further preferably 20 to 120 minutes.

At a temperature T₂The heating treatment for maintaining the pressure below may be performed under normal pressure or under reduced pressure. It is preferable that: preferably at a temperature T₁The heating treatment was performed under the same air pressure.

Can be at a temperature T₁After the next heat treatment, the resin composition layer is temporarily cooled and subjected to a temperature T₂And (4) heating treatment. Alternatively, or in addition, the temperature T may be₁After heat treatment at a temperature T₂Next, a heating treatment is performed without cooling the resin composition layer. Temperature T₁Heat treatment and temperature T₂The following heat treatment may be performed using the same heat treatment apparatus, or the temperature T may be performed using the first heat treatment apparatus₁Performing a heat treatment at a temperature T using a second heat treatment device different from the first heat treatment device₂And (4) heating treatment. The heat treatment apparatus is not particularly limited as long as it can form a cured body by thermally curing the resin composition layer on the base substrate, and conventionally known apparatuses can be used. For example, an oven, heat and pressure, or the like can be used as the heat treatment apparatus. For example, it may be adjusted to temperature T in use₁To implement the temperature T₁After the heating treatment, the heating object is transferred to the temperature T₂To implement the temperature T₂And (4) heating treatment. Alternatively, the temperature T may be implemented by using a heat treatment apparatus capable of realizing a temperature rise program₁After the heat treatment, from the temperature T₁Heating to temperature T₂And applying a temperature T₂And (4) heating treatment. At this time, from the temperature T₁Heating to temperature T₂The rate of (b) is not particularly limited, and may be any value and may be in the same range as the temperature increase rate in the heat curing condition (ii) described later.

For the thermosetting condition (i), provided that it is included in the temperature T in order₁Heating treatment for holding and specific temperature T₁Higher temperature T₂The heating treatment for holding may be performed next, and the heating treatment for holding at other temperature may be further performed. That is, the step curing of the thermosetting condition (i) is not limited to the heat treatment of 2 steps, and may include the heat treatment of 3 or more steps.

Thermal curing conditions (ii)

The thermosetting of the resin composition layer under the condition satisfying (ii) is sometimes referred to as "temperature-programmed curing".

Temperature T₂Value of (D), at temperature T₂The time for the next holding may be the same as that described for the thermosetting condition (i).

With respect to the heat curing condition (ii), the temperature is raised to the temperature T from the viewpoint of realizing a light reflective substrate exhibiting high reflectance and good base adhesion₂The temperature rise rate at the time of heating is in the range of 0.5 to 30 ℃/min, preferably 1 ℃/min or more, more preferably 1.5 ℃/min or more, 2 ℃/min or more, or 2.5 ℃/min or more, and preferably 25 ℃/min or less, more preferably 20 ℃/min or less, 15 ℃/min or less, 10 ℃/min or less, 8 ℃/min or less, or 6 ℃/min or less.

The temperature rise rate does not need to be from the temperature rise start temperature T₀Starting to temperature T₂May be changed within the above-mentioned suitable range while being kept constant. Temperature rise onset temperature T₀The temperature is not particularly limited, and may be the ambient temperature (e.g., room temperature) at the time of carrying out the method of the present invention.

The temperature-increasing curing may be carried out under normal pressure or under reduced pressure. It is preferable that: preferably at the same air pressure as described for the step cure.

In addition to this, the present invention is,the heat treatment apparatus used for the temperature-raising curing may be one capable of raising the temperature of the resin composition layer on the base substrate at a predetermined rate and at a temperature T₂The heating may be carried out by any known means, without any particular limitation. For example, an oven, heat and pressure, or the like can be used as the heat treatment apparatus.

In the step (B), a reflection sheet formed of a cured product of the resin composition layer is formed on the base substrate. The manufactured light reflection substrate includes a reflection sheet as an interlayer insulating layer or a solder resist layer. When the reflective sheet is included as the interlayer insulating layer, the method of the present invention may further include a step of forming a conductor layer on the reflective sheet. This process may be performed according to various methods for manufacturing printed circuit boards known to those skilled in the art.

The method of the present invention may further include a step of disposing a light source on the (C) reflective sheet (cured body of the resin composition layer). Examples of the light source include a Light Emitting Diode (LED), a small LED, and a micro LED.

As shown in fig. 1, the light reflection substrate 1 has a reflection sheet 3 formed on a substrate 2, and a light source 4 such as a Light Emitting Diode (LED) is disposed on a surface 31 of the reflection sheet 3. The substrate 2 corresponds to the above-described "base substrate" (the conductor layer is not shown in fig. 1), and the surface 31 of the reflector 3 corresponds to the above-described "surface on the side not in contact with the base substrate".

The reflection sheet may have a concave portion in addition to the planar surface as shown in fig. 1 on the light source side in order to improve the extraction efficiency of light emitted from the light source. When the surface of the reflection sheet has a concave portion, the light source is preferably disposed in the concave portion.

If necessary, after being electrically connected to the light source, the light source may be fixed by sealing or the like.

The light-reflecting substrate produced by the method of the present invention has a phase rich in an inorganic filler component in a region near the surface of the reflection sheet (cured body of the resin composition layer) on the side not in contact with the base substrate, and therefore exhibits a high light reflectance, for example, a reflectance of preferably 85% or more, more preferably 86% or more or 88% or more, and further preferably 90% or more, 92% or more, 94% or more or 95% or more with respect to light having a wavelength of 460 nm. The upper limit of the light reflectance may be 100% or less. Therefore, in one preferred embodiment, the light-reflecting substrate exhibits a reflectance of 85% or more with respect to a light having a wavelength of 460 nm. The light reflectance of the cured product can be measured by using, for example, a multichannel spectroscope (available from Otsuka electronics Co., Ltd., MCPD-7700).

The light-reflecting substrate produced by the method of the present invention can realize such a high light reflectance without lowering the adhesion of the base. For example, in the light reflective substrate produced by the method of the present invention, the reflective sheet (cured body of the resin composition layer) exhibits an adhesion strength of preferably 0.3kgf/cm or more, more preferably 0.32kgf/cm or more, 0.34kgf/cm or more, 0.35kgf/cm or more, 0.36kgf/cm or more, 0.38kgf/cm or more, or 0.4kgf/cm or more with respect to the conductor layer of the base substrate. The upper limit of the adhesion strength may be 1kgf/cm or less, 0.9kgf/cm or less, or the like. Therefore, in one preferred embodiment, the adhesion strength between the reflective sheet of the light reflective substrate and the conductive layer of the base substrate is 0.3kgf/cm or more.

[ semiconductor device ]

A semiconductor device can be manufactured using the light-reflecting substrate manufactured by the method of the present invention. The semiconductor device can be manufactured by mounting a component (semiconductor chip) on a conductive portion of the light reflecting substrate. Examples thereof include backlights of liquid crystal displays of portable terminals, computers, televisions, and the like; a semiconductor device such as a light source of a lighting fixture is mounted with a Light Emitting Diode (LED) that emits light with low power.

Examples

The present invention will be specifically described below with reference to examples. The present invention is not limited to these examples. In the following, the terms "part by mass" and "%" representing the amount are used to indicate "part by mass" and "% by mass", respectively, unless otherwise stated. In particular, the temperature conditions and pressure conditions when the temperature is not specified are room temperature (25 ℃ C.) and atmospheric pressure (1 atm).

< production example 1> production of resin sheet 1

(1) Preparation of resin composition

A liquid bisphenol A-type epoxy resin ("jER 828 EL" manufactured by Mitsubishi ケミカル, having an epoxy equivalent of 180g/eq.) was added in an amount of 5 parts, a solid fluorine atom-containing epoxy resin ("YX 7760" manufactured by Mitsubishi ケミカル, having an epoxy equivalent of 245g/eq.) was added in an amount of 5 parts, and a phenoxy resin having a biphenyl skeleton and a cyclohexane skeleton ("YX 7200B 35" manufactured by Mitsubishi ケミカル, having a weight average molecular weight of 30,000, a 20 μm film light transmittance (450nm) of 88%, a solid content of 35% by mass MEK solution) was added in an amount of 20 parts to the MEK 10 parts, followed by heating and dissolving with stirring, and mixing titanium oxide ("PX 3788" manufactured by Sakai chemical industries, treated with a phenylsilane coupling agent ("KBM-103" manufactured by Yukai chemical industries), having an average particle diameter of 0.26 μm and a specific surface area of 13.2m²(g): "SO-C2" manufactured by アドマテックス corporation, "treated with a methacrylic silane coupling agent (" KBM-503 "manufactured by shin-Etsu chemical industries), having an average particle diameter of 0.5 μm and a reflectance of about 80% for light having a wavelength of 500 nm)," bisphenol AF "(a solution prepared by adjusting" BIS-AF "manufactured by セントラル Nitro jus to have a nonvolatile content of 50% with MEK) 4 parts, and" phosphorus curing accelerator "(TBP-DA manufactured by Beixing chemical industries) 0.2 part, were uniformly dispersed by a high-speed rotary stirrer to prepare a resin composition (varnish).

(2) Production of resin sheet

As a support, a PET film with a release layer ("PET 501010" manufactured by リンテック Co., Ltd., thickness: 38 μm) was prepared. The resin composition prepared in the above (1) was uniformly coated on the release layer of the support so that the thickness of the dried resin composition layer became 50 μm. Thereafter, the resin composition 1 was heated at 80 ℃ for 4 minutes, thereby obtaining a resin sheet 1 including a resin composition layer having a thickness of 50 μm.

< production example 2> production of resin sheet 1-RCC

Resin sheets 1-RCC were produced in the same manner as in production example 1, except that an electrolytic copper foil ("3 EC-III" manufactured by Mitsui Metal mining Co., Ltd., thickness: 35 μm) was used as the support instead of the PET film with a release layer ("PET 501010" manufactured by リンテック Co., Ltd., thickness: 38 μm). The resin composition is applied to the glossy surface of the electrolytic copper foil.

< production example 3> production of resin sheet 2

Resin sheet 2 was produced in the same manner as in production example 1 except that 5 parts of a hydrogenated liquid epoxy resin ("YX 8000" manufactured by mitsubishi ケミカル and having an epoxy equivalent of 205g/eq.) and 5 parts of a biphenyl type epoxy resin ("YX 4000H" manufactured by mitsubishi ケミカル and having an epoxy equivalent of 195g/eq.) were used instead of 5 parts of a liquid bisphenol a type epoxy resin ("jER 828 EL" manufactured by mitsubishi ケミカル and having an epoxy equivalent of 180g/eq.) and 5 parts of a solid fluorine atom-containing epoxy resin ("YX 7760" manufactured by mitsubishi ケミカル and having an epoxy equivalent of 245g/eq.), respectively.

< production example 4> production of resin sheet 3

Resin sheet 3 was produced in the same manner as in production example 1, except that (1) the amount of titanium oxide (made by sakai chemical industry corporation, "PX 3788" treated with a phenyl silane coupling agent) was changed from 10 parts to 20 parts, and (2) spherical silica (made by アドマテックス corporation, "SO-C2" treated with a methacrylic silane coupling agent) was not added.

< production example 5> production of resin sheet 4

(1) Preparation of resin composition

A biphenyl type epoxy resin ("NC 3000H" manufactured by Nippon chemical company, "epoxy equivalent is about 272g/eq.) was dissolved in 3 parts, a tetrahydroxyphenylethane type epoxy resin (" JeR1031S "manufactured by Mitsubishi ケミカル," epoxy equivalent is about 200g/eq.) was dissolved in 2 parts, a bisphenol A type epoxy acrylate ("ZAR-2000" manufactured by Nippon chemical company, "acid number 99mgKOH/g, nonvolatile content 70%), a diluent (" DPHA "manufactured by Nippon chemical company," dipentaerythritol hexaacrylate, acrylic equivalent is about 96g/eq.) was dissolved in 1 part of MEK 6 parts and 10 parts of ethyldiglycol acetate under heating with stirring. Titanium oxide (made by Sakai chemical industry Co., Ltd. "PX 3788" and a phenyl silane coupling agent (made by shin-Etsu chemical industry Co., Ltd. "KBM)103'), average particle diameter of 0.26 μm and specific surface area of 13.2m²(ii)/g, a reflectance with respect to light having a wavelength of 500nm was 99%), 8 parts of spherical silica ("SO-C2" manufactured by アドマテックス, treated with a methacrylic silane coupling agent ("KBM-503" manufactured by shin-Etsu chemical industries), having an average particle diameter of 0.5 μm and a reflectance with respect to light having a wavelength of 500nm was 80%), and 0.04 part of a photopolymerization initiator ("Irgacure 819" manufactured by BASF) and bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide were uniformly dispersed by a high-speed rotary stirrer to prepare a resin composition.

(2) Production of resin sheet

Using the resin composition prepared in the above (1), a resin sheet 4 was produced in the same manner as in production example 1. The resin sheet 4 includes a support and a photosensitive resin composition layer provided on the support.

The composition of the resin composition layer and the support for each of the resin sheets produced are summarized in table 1.

[ Table 1]

< example 1>

(A) Manufacture of substrate A

(A1) Base treatment of circuit substrates

By etching, circuit patterns were formed on both sides of a glass cloth substrate epoxy resin double-sided copper-clad laminate (copper foil 18 μm thick, substrate 0.8mm thick, "R5715 ES" manufactured by panasonic electric corporation), and an inner layer circuit substrate having an in-plane copper area of 30% was produced. The copper circuit of the inner layer circuit board thus obtained was roughened with a microetching solution ("CZ 8100" manufactured by メック Co.), and then dried at 190 ℃ for 30 minutes.

(A2) Lamination of resin sheets

The resin sheet 1 obtained in the above production example was laminated on both sides of the inner layer circuit board subjected to the base treatment in such a manner that the resin composition layer was bonded to the inner layer circuit board using a batch vacuum pressure laminator ("MVLP-500" manufactured by the name machine corporation). The lamination was performed by reducing the pressure for 30 seconds to a pressure of 13hPa or less, and then pressing at 120 ℃ for 30 seconds under a pressure of 0.74 MPa.

(A3) Smoothing of resin sheet

Subsequently, the laminated resin sheet was thermally pressed at 100 ℃ and 0.5MPa for 60 seconds under atmospheric pressure to smooth the sheet. In this manner, a laminate with a support, which is composed of the support, the resin composition layer, the inner circuit board, the resin composition layer, and the support, was obtained.

(A4) Thermal curing of resin composition layers

The support was peeled from the laminate with a support obtained in (a3) above to obtain a laminate having a layer of the resin composition layer/the inner circuit board/the resin composition layer. Then, the laminate was heated (pre-cured) in an oven at 100 ℃ for 30 minutes and then heated (post-cured) in an oven at 180 ℃ for 90 minutes to thermally cure the resin composition layer. Thus, a substrate a having a layer structure of a cured body/inner layer circuit substrate/cured body was obtained.

(B) Manufacture of substrate B

(B1) Base treatment of copper foil

The glossy surface of an electrolytic copper foil ("3 EC-III" manufactured by mitsui metal mining corporation, 35 μm thick) was immersed in a microetching solution ("メックエッチボンド CZ-8101" manufactured by メック corporation), and the copper surface was roughened (Ra value 1 μm) to perform rust prevention treatment (CL 8300). Next, the heating treatment was carried out in an oven at 130 ℃ for 30 minutes. Hereinafter, the obtained copper foil is referred to as a CZ copper foil.

(B2) Lamination of resin sheets

The resin sheet 1 obtained in the above production example was laminated on one surface of a CZ copper foil to produce a copper foil-equipped resin sheet having a support/resin composition layer/CZ copper foil layer. The lamination conditions were the same as those in (a2) above.

(B3) Thermal curing of resin composition layers

The support was peeled from the copper foil-attached resin sheet produced in (B2) above to obtain a laminate having a resin composition layer/CZ copper foil layer. Then, the laminate was heated under the same curing conditions as in (a4) above to thermally cure the resin composition layer. Thus, a cured product with copper foil having a layer of cured product/CZ copper foil was obtained.

(B4) Fastening to a circuit substrate

The cured product with copper foil obtained in (B3) was bonded to both surfaces of the base-treated circuit board using an adhesive (アロン α EX) so that the cured product was in contact with the circuit board. The circuit board subjected to the base treatment was the same as the circuit board prepared in (a1) above.

Next, the cured product with copper foil and the circuit board were laminated under the same conditions as in (a2) above. Thus, a substrate B having a layer of a CZ copper foil/a cured product/a circuit board/a cured product/a CZ copper foil was obtained.

< example 2>

Substrates a and B were obtained in the same manner as in example 1 except that the support was not peeled off at the time of thermosetting of the resin composition layer, and the resin composition layer was thermally cured with the support attached, and thereafter, the support was peeled off.

< example 3>

Substrates a and B were obtained in the same manner as in example 1, except that (1) the support was not peeled off at the time of thermal curing of the resin composition layer, and the support was peeled off after the resin composition layer was thermally cured with the support, (2) the temperature was raised from 25 ℃ to 180 ℃ in an oven at a temperature rise rate of 2.6 ℃/min, and then the resin composition layer was heated at 180 ℃ for 90 minutes to thermally cure the resin composition layer.

< example 4>

Substrates a and B were obtained in the same manner as in example 1, except that (1) the support was not peeled off at the time of thermal curing of the resin composition layer, and the support was peeled off after the resin composition layer was thermally cured with the support, (2) the temperature was raised from 25 ℃ to 180 ℃ at a temperature raising rate of 2.6 ℃/min under heating and pressing, and then the resin composition layer was thermally cured by heating at 180 ℃ for 90 minutes.

< example 5>

Substrates a and B were obtained in the same manner as in example 1, except that (1) the resin sheet 1-RCC was used instead of the resin sheet 1, and (2) the support was not peeled off at the time of thermosetting of the resin composition layer, and the resin composition layer was thermally cured with the support and then the support was peeled off.

< example 6>

Substrates a and B were obtained in the same manner as in example 1, except that the resin sheet 2 was used instead of the resin sheet 1.

< example 7>

Substrates a and B were obtained in the same manner as in example 1, except that the resin sheet 3 was used instead of the resin sheet 1.

< comparative example 1>

Substrates a and B were obtained in the same manner as in example 1, except that (1) the support was not peeled off at the time of thermal curing of the resin composition layer, and the resin composition layer was thermally cured with the support, and thereafter the support was peeled off, and (2) a heating object was put into an oven heated to 180 ℃, and heated at 180 ℃ for 90 minutes to thermally cure the resin composition layer.

< comparative example 2>

Substrates a and B were obtained in the same manner as in example 1, except that (1) the resin sheet 4 (resin sheet including a photosensitive resin composition layer) was used instead of the resin sheet 1, and (2) the resin composition layer was photocured according to the following procedure.

(photocuring step): using 100mJ/cm²The photosensitive resin composition layer is exposed to ultraviolet light to be cured. Thereafter, a1 mass% sodium carbonate aqueous solution at 30 ℃ was sprayed and developed as a developing solution for 2 minutes at a spray pressure of 0.2MPa over the entire surface of the photosensitive resin composition layer. After spray development, 1J/cm²Further, the photosensitive resin composition layer was cured by heating at 190 ℃ for 90 minutes.

Hereinafter, various measurement methods and evaluation methods will be described.

< measurement of light reflectance >

The substrates A produced in examples and comparative examples were cut into a width of 50mm and a length of 50mm, and the reflectance (%) for light having a wavelength of 460nm was measured by a multi-channel spectroscope (available from Otsuka electronics, MCPD-7700) and evaluated according to the following criteria.

Evaluation criteria for light reflectance:

very good: the reflectivity is more than 95%

O: the reflectivity is more than 90 percent and less than 95 percent

And (delta): the reflectivity is more than 85 percent and less than 90 percent

X: the reflectivity is less than 85%.

< measurement of substrate adhesion >

The substrates B obtained in examples and comparative examples were cut into pieces of 150X 30 mm. The copper foil portion of the chip was subjected to cutting by a cutter to cut a portion having a width of 10mm and a length of 100mm, one end of the copper foil was peeled off and held by a jig (model オートコム tester "AC-50C-SL" manufactured by ティー seed エス seed イー corporation), 35mm was peeled off in the vertical direction at a speed of 50 mm/min at room temperature using a インストロン universal tester, and the load at this time was measured in accordance with JIS C6481 and evaluated in accordance with the following criteria.

Evaluation criteria for substrate adhesion:

very good: the adhesion strength is more than 0.5kgf/cm

Good: the adhesion strength is more than 0.3kgf/cm and less than 0.5kgf/cm

X: the adhesion strength is less than 0.3 kgf/cm.

The conditions for heat curing of the resin composition layers in examples and comparative examples and the evaluation results of the substrates produced are shown in table 2. It should be noted that: in the substrates manufactured in examples, a phase rich in an inorganic filler component was present in a region near the surface of the cured body (reflective sheet) of the resin composition layer on the side not in contact with the base substrate, and a phase rich in a resin component was present in a region near the main surface of the reflective sheet in contact with the base substrate.

[ Table 2]

Description of the reference numerals

1 light-reflecting substrate

2 base plate

3 reflective sheet

31 face of reflecting sheet

4 light source.

Claims

1. A method for manufacturing a light-reflecting substrate, comprising the following steps (A) and (B) in this order:

2. The method according to claim 1, wherein the support is peeled between the step (A) and the step (B).

3. The method of claim 1, wherein the resin composition layer further comprises a thermosetting resin.

4. The method according to claim 1, wherein the content of the white inorganic pigment is 20 to 60% by mass, based on 100% by mass of nonvolatile components in the resin composition layer.

5. The method of claim 3, wherein the thermosetting resin comprises an epoxy resin.

6. The method according to claim 5, wherein the content of the epoxy resin is 1 to 50% by mass, based on 100% by mass of nonvolatile components in the resin composition layer.

7. The method according to claim 1, wherein the white inorganic pigment is 1 or more selected from the group consisting of alumina, titania, zirconia, magnesia, barium titanate, zinc oxide, cerium oxide and calcium carbonate.

8. The method of claim 1, wherein the light reflective substrate exhibits a reflectance of 85% or more for light having a wavelength of 460 nm.

9. The method according to any one of claims 1 to 8, wherein the cured product of the resin composition layer in the light-reflecting substrate has an adhesion strength of 0.3kgf/cm or more to the conductor layer of the base substrate.