JP2016000462A - Substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate that exhibits a preferable whiteness degree even in a high-temperature environment.SOLUTION: The substrate includes at least a resin layer. The resin layer contains a resin essentially comprising a polyimide resin. The substrate exhibits a Hunter brightness degree of 84% or more of the resin layer after heated at 260°C for 60 minutes. It is preferable that: the substrate exhibits a retention rate of 93% or more in the Hunter brightness degree of the resin layer after heated at 260°C for 60 minutes; the resin layer side of the substrate exhibits a total ray reflectance of 75% or more after heated at 260°C for 60 minutes; and the retention rate of the total ray reflectance at the resin layer side is 94% or more after heated at 260°C for 60 minutes.

Description

  The present invention relates to a substrate, particularly a substrate for mounting a light emitting element such as a light emitting diode (LED) or electroluminescence (EL), a substrate for barcode printing, and the like.

  Various “white reflective substrates for mounting light emitting elements such as light emitting diodes and electroluminescence” have been proposed in the past (for example, Japanese Patent Application Laid-Open Nos. 2006-110999, 2009-149878, and 2009-149879). No., JP-A 2010-275333, JP-A 2010-275561, and JP-A 2011-251450.

JP 2006-110999 A JP 2009-149878 A JP 2009-149879 A JP 2010-275333 A JP 2010-275561 A JP 2011-251450 A

  Incidentally, such a white reflective substrate for mounting a light emitting element is required to have heat resistance under a high temperature environment.

  The subject of this invention is providing the base | substrate which shows favorable whiteness also in a high temperature environment.

  The substrate according to one aspect of the present invention includes at least a resin layer. The “base” here is, for example, a circuit board for mounting a light emitting element, a coverlay, a board for barcode printing, or the like. Further, the substrate may be composed only of the resin layer (that is, may be a resin film), or may be a laminate of the resin layer and another layer such as a metal layer or a ceramic layer. . The resin layer contains a resin. The resin is mainly composed of a polyimide resin. Here, the “main component” refers to a resin component that occupies 50% by volume or more of the resin. The resin is preferably only a polyimide resin. And this base | substrate has the Hunter whiteness of the resin layer after heat-processing for 60 minutes at 260 degreeC being 84% or more. For this reason, this base | substrate can show favorable whiteness also in a high temperature environment. For example, in the case where the light emitting element is used or has been used in the substrate on which the light emitting element is mounted, the substrate is taken out and subjected to heat treatment at 260 ° C. for 60 minutes. If the above values are shown, the substrate belongs to the technical scope of the present invention. The same concept is applied to the total light reflectance and spectral reflectance shown below.

  In addition, it is preferable that the maintenance rate of the Hunter whiteness of the resin layer after the heat treatment at 260 ° C. for 60 minutes is 93% or more. This is because the whiteness of the substrate can be maintained well even in a high temperature environment. The hunter whiteness that serves as a reference for the maintenance ratio is not limited to the initial hunter whiteness (for example, the hunter whiteness of the substrate before mounting the light emitting element). For example, when the light emitting element is used or has been used in a substrate on which a light emitting element is mounted, the substrate is taken out and heated at 260 ° C. for 60 minutes, and then the Hunter whiteness of the resin layer is 84% or more. If the value shows a value and the maintenance ratio of the heating period shows a value of 93% or more, the substrate belongs to the technical scope of the present invention. The same concept is applied to the total light reflectivity and the maintenance rate of the spectral reflectivity shown below.

  The above-mentioned substrate preferably has a total light reflectance of 75% or more on the resin layer side after heat treatment at 260 ° C. for 60 minutes. This is because the substrate can exhibit good reflection characteristics even in a high temperature environment.

  Moreover, it is preferable that the above-mentioned base | substrate is 94% or more of the maintenance factor of the total light reflectivity in the resin layer side after heat-processing for 60 minutes at 260 degreeC. This is because the reflection characteristics of the substrate can be maintained well even in a high temperature environment.

  Moreover, it is preferable that the above-mentioned base | substrate has a 470 nm wavelength light beam reflectance in the resin layer side after heat-processing at 260 degreeC for 60 minute (s) 72% or more. This is because the substrate can exhibit good reflection characteristics even in a high temperature environment.

  Moreover, it is preferable that the above-mentioned base | substrate has 89% or more of the maintenance factor of 470 nm wavelength light reflectance in the resin layer side after heat-processing at 260 degreeC for 60 minute (s). This is because the reflection characteristics of the substrate can be maintained well even in a high temperature environment.

  Moreover, it is preferable that the above-mentioned base | substrate has the dielectric breakdown strength of a resin layer of 95 kV / mm or more. This is because the lifetime of the substrate when using the light emitting element can be sufficiently increased.

It is a top view of the light emitting element mounting printed wiring board implement | achieved by applying the base | substrate which concerns on embodiment of this invention to the printed wiring board for light emitting element mounting. It is AA sectional drawing of FIG. It is a top view of the other light emitting element mounting printed wiring board implement | achieved by applying the base | substrate which concerns on embodiment of this invention to the printed wiring board for light emitting element mounting. It is a figure which shows the BB sectional drawing of FIG. 3 combined with the AA sectional view of FIG.

<Configuration of Substrate According to Embodiment of the Present Invention>
The substrate according to the embodiment of the present invention is, for example, a plate-like or film-like substrate, specifically, a substrate for mounting a light emitting element, a flexible substrate, a substrate for bar coat printing, a flexible substrate, or the like. . The base according to the present embodiment is provided with at least a resin layer. In the present embodiment, this resin layer has an electrical insulation function, a light reflection function, and the like. Moreover, you may provide other layers, such as another heat-resistant resin layer, a metal layer, a ceramic layer other than a resin layer, as needed. That is, the substrate may be a laminate. In addition, such other layers may be provided on one side of the resin layer or may be provided on both sides. However, when the light reflection function of the resin layer is used, the other layer needs to be provided on one side of the resin layer.

  Hereinafter, the resin layer and other layers that can constitute the substrate according to the present embodiment will be described in detail.

1. Resin Layer The resin layer is mainly formed from a resin and a filler. Hereinafter, the resin and the filler will be described in detail.

(1) Resin The resin contains a specific polyimide resin (hereinafter referred to as “specific polyimide resin”) as a main component. In the present embodiment, the resin is preferably composed only of a specific polyimide resin. Moreover, when resin other than specific polyimide resin contains in resin, resin other than specific polyimide resin can be added to resin in the range which does not impair the main point of this invention.

  Specific polyimide resins are (a) 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2-bis [4- (dicarboxyphenoxy) phenyl] propanoic dianhydride and 4,4. A structural unit derived from at least one tetracarboxylic dianhydride selected from the group consisting of '-(hexafluoroisopropylidene) diphthalic anhydride, and (b) 3,3'-diaminodiphenyl sulfone, It is at least one polyimide resin composed of a structural unit derived from at least one diamine selected from the group consisting of 4′-diaminodiphenylsulfone and bis [4- (3-aminophenoxy) phenyl] sulfone. That is, the specific polyimide resin may be a kind of polyimide resin composed of the specific monomer, or may be a blend of plural kinds of polyimide resins composed of the specific monomer.

(2) Filler The filler mainly contains a white pigment. In the present embodiment, the filler is preferably composed only of a white pigment. In addition, when the filler contains a filler other than the white pigment, the filler other than the white pigment can be added to the filler in a range that does not impair the gist of the present invention.

  The white pigment is not particularly limited as long as it is a known white pigment used industrially. For example, titanium dioxide, titanium oxide, talc, barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, Fixed silica, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, zinc hydroxide, aluminum nitride, silicon nitride, boron nitride, diamond powder, zirconium silicate, zirconium oxide, magnesium hydroxide, basic carbonate, Examples thereof include basic lead sulfate, lead sulfate, zinc sulfide, antimony oxide, titanium nitride, cerium fluoride, cerium oxide, mica, mica powder, silicone powder, and organic resin filler. The titanium dioxide is particularly preferably rutile titanium dioxide. Examples of the organic resin filler include polystyrene-based organic resin fillers, poly (meth) acrylate-based organic resin fillers, (benzo) guanamine-based organic resin fillers, acrylic rubber-based organic resin fillers, and rubber-based organic resin fillers. In addition, the above-mentioned white pigment may be used independently and 2 or more types may be mixed and used.

  The filler preferably occupies a volume in the range of 10% to 40% by volume in the resin layer, more preferably occupies a volume in the range of 10% to 35% by volume. It is more preferable to occupy a volume in the range of 30% by volume or more and 30% by volume or less, more preferably in a range of 15% to 30% by volume, more preferably in the range of 20% to 30% by volume. It is particularly preferable to occupy a volume within the range of 25% by volume to 30% by volume.

2. Other layers As described above, the other layers are, for example, other heat-resistant resin layers, metal layers, ceramic layers, and the like. The metal layer is composed of a metal plate or foil such as aluminum or copper. This metal layer may form a circuit. In addition, the surface of the other layer is subjected to a treatment for enhancing the adhesive force such as polishing treatment, etching treatment, blast treatment, corona discharge treatment, sputtering treatment, UV treatment, plating treatment, silane coupling agent treatment, primer coating, etc. Also good.

<Characteristics of the substrate according to the embodiment of the present invention>
The substrate according to the present embodiment has a characteristic of maintaining high hunter whiteness even in a high temperature environment. In addition, the substrate additionally has a characteristic of maintaining good total light reflectance and spectral reflectance even under a high temperature environment, and excellent dielectric breakdown strength. Hereinafter, these various characteristics will be described in detail.

(1) Heat resistance of hunter whiteness In the present embodiment, the hunter whiteness of the resin layer after the substrate is heated at 260 ° C. for 60 minutes is 84% or more. In addition, the Hunter whiteness at this time is preferably 86% or more, more preferably 88% or more, further preferably 90% or more, further preferably 92% or more, 94% More preferably, it is 96% or more, more preferably 98% or more, and most preferably 100% or more.

  In the present embodiment, the hunter whiteness of the resin layer after heat-treating the substrate at 280 ° C. for 30 minutes is preferably 84% or more, more preferably 86% or more, and 88% or more. More preferably, it is more preferably 90% or more, further preferably 92% or more, further preferably 94% or more, further preferably 96% or more, and 98% or more. Particularly preferred is 100% or more.

  In the present embodiment, the hunter whiteness of the resin layer after heat-treating the substrate at 150 ° C. for 392 hours is preferably 85% or more, more preferably 86% or more, and 88% or more. More preferably, it is more preferably 90% or more, further preferably 92% or more, further preferably 94% or more, further preferably 96% or more, and 98% or more. Particularly preferred is 100% or more.

  In this embodiment, the retention ratio of the Hunter whiteness of the resin layer after the substrate is heat-treated at 260 ° C. for 60 minutes is preferably 93% or more, more preferably 95% or more, 97 % Or more, more preferably 99% or more, and most preferably 100% or more.

  In this embodiment, the retention ratio of the Hunter whiteness of the resin layer after the substrate is heat-treated at 280 ° C. for 30 minutes is preferably 93% or more, more preferably 95% or more, and 97 % Or more, more preferably 99% or more, and most preferably 100% or more.

  In the present embodiment, the retention ratio of the Hunter whiteness of the resin layer after heat-treating the substrate at 150 ° C. for 392 hours is preferably 95% or more, more preferably 97% or more, and 99 % Or more is more preferable, and 100% or more is most preferable.

(2) Heat resistance of total light reflectivity In this embodiment, the total light reflectivity on the resin layer side after heat-treating the substrate at 260 ° C. for 60 minutes is preferably 75% or more, and 80% or more. More preferably, it is more preferably 85% or more, still more preferably 90% or more, particularly preferably 95% or more, and most preferably 100%.

  In the present embodiment, the total light reflectance on the resin layer side after heat-treating the substrate at 280 ° C. for 30 minutes is preferably 74% or more, more preferably 80% or more, and 85%. More preferably, it is more preferably 90% or more, particularly preferably 95% or more, and most preferably 100%.

  In the present embodiment, the total light reflectance on the resin layer side after the substrate is heat-treated at 150 ° C. for 392 hours is preferably 78% or more, more preferably 80% or more, and 85%. More preferably, it is more preferably 90% or more, particularly preferably 95% or more, and most preferably 100%.

  In addition, the maintenance ratio of the total light reflectance on the resin layer side after heat-treating the substrate at 260 ° C. for 60 minutes is preferably 94% or more, more preferably 95% or more, and 96% or more. More preferably, it is particularly preferably 98% or more, and most preferably 100% or more.

  Further, the maintenance ratio of the total light reflectance on the resin layer side after the substrate is heat-treated at 280 ° C. for 30 minutes is preferably 94% or more, more preferably 95% or more, and 96% or more. More preferably, it is particularly preferably 98% or more, and most preferably 100% or more.

  In addition, the maintenance ratio of the total light reflectance on the resin layer side after heat-treating the substrate at 150 ° C. for 392 hours is preferably 94% or more, more preferably 95% or more, and 96% or more. More preferably, it is particularly preferably 98% or more, and most preferably 100% or more.

(3) Heat resistance of spectral reflectance The 470 nm wavelength light reflectance on the resin layer side after heat treating the substrate at 260 ° C. for 60 minutes is preferably 72% or more, more preferably 75% or more, It is more preferably 80% or more, more preferably 85% or more, further preferably 90% or more, particularly preferably 95% or more, and most preferably 100%.

  Further, the 470 nm wavelength light reflectance on the resin layer side after heat-treating the substrate at 280 ° C. for 30 minutes is preferably 70% or more, more preferably 75% or more, and more preferably 80% or more. More preferably, it is more preferably 85% or more, further preferably 90% or more, particularly preferably 95% or more, and most preferably 100%.

  Further, the 470 nm wavelength light reflectance on the resin layer side after heat-treating the substrate at 150 ° C. for 392 hours is preferably 70% or more, more preferably 75% or more, and more preferably 80% or more. More preferably, it is more preferably 85% or more, further preferably 90% or more, particularly preferably 95% or more, and most preferably 100%.

  In addition, the maintenance factor of the 470 nm wavelength light reflectance on the resin layer side after heat-treating the substrate at 260 ° C. for 60 minutes is preferably 89% or more, more preferably 90% or more, and 92% or more. More preferably, it is 94% or more, more preferably 95% or more, further preferably 96% or more, particularly preferably 98% or more, and 100% or more. Most preferably it is.

  Further, the maintenance rate of the 470 nm wavelength light reflectance on the resin layer side after the substrate is heat-treated at 280 ° C. for 30 minutes is preferably 89% or more, more preferably 90% or more, and 92% or more. More preferably, it is 94% or more, more preferably 95% or more, further preferably 96% or more, particularly preferably 98% or more, and 100% or more. Most preferably it is.

  Further, the maintenance ratio of the 470 nm wavelength light reflectance on the resin layer side after heat treatment of the substrate at 150 ° C. for 392 hours is preferably 89% or more, more preferably 90% or more, and 92% or more. More preferably, it is 94% or more, more preferably 95% or more, further preferably 96% or more, particularly preferably 98% or more, and 100% or more. Most preferably it is.

(4) Dielectric breakdown strength The dielectric breakdown strength of the resin layer is preferably 95 kV / mm or more, more preferably 100 kV / mm or more, further preferably 105 kV / mm or more, and 110 kV / mm or more. More preferably, it is 115 kV / mm or more. In addition, although the upper limit of this dielectric breakdown strength is so preferable that it is high, it is 200 kV / mm, for example.

<The manufacturing method of the resin layer which concerns on embodiment of this invention>
First, a filler containing a white pigment is added to a resin solution containing a specific polyimide resin precursor as a main component, and the mixture is stirred until the filler is uniformly dispersed in the resin solution. Then, the filler-containing resin solution is applied onto the substrate by a method such as a screen printing method. Then, the coating film of the filler-containing resin solution is heated at a temperature equal to or higher than the temperature at which the precursor of the specific polyimide resin is imidized. Thus, the resin layer according to the present embodiment is formed. In addition, after that, the resin layer may be peeled off from the base material and used together with the base material.

<Application Example of Substrate according to Embodiment of the Present Invention>
The substrate according to the present embodiment can be applied to, for example, the light emitting element mounting printed wiring board 100 shown in FIGS. 1 and 2. As shown in FIGS. 1 and 2, the light emitting element-mounting printed wiring board 100 mainly includes a printed wiring board 130, a light emitting element 120, and a white reflective layer 110. Of these elements, the combination of the printed wiring board 130 and the white reflective base layer 110 corresponds to the “base” of the present application. In addition, the “light emitting element” referred to here is, for example, a light emitting diode (LED) or electroluminescence (EL).

  Moreover, the base | substrate which concerns on this Embodiment can be applied also to the reflecting plate 200 shown by FIG. 3, for example. As shown in FIG. 3, the reflecting plate 200 is mainly composed of a transparent substrate 210 and a white reflecting layer 110. This reflector corresponds to the “base” of the present application. The transparent substrate 210 is formed of a transparent material such as glass, polyethylene terephthalate, or polyethylene naphthalate. A plurality of white reflective layers 110 are arranged in a pattern on the transparent substrate 210. As shown in FIG. 4, the reflector 200 can be disposed above the light emitting element mounting printed wiring board 100 shown in FIGS. 1 and 2. At this time, the reflective plate 200 is disposed so that the white reflective layer 110 of the light emitting element mounting printed wiring board 100 and the white reflective layer 110 of the reflective plate 200 face each other.

<Characteristics of the substrate according to the embodiment of the present invention>
(1)
The substrate according to the present embodiment has a resin layer, and the resin layer is composed of “a resin mainly composed of a specific polyimide resin” and “a filler mainly composed of a white pigment”. This resin layer has a Hunter whiteness of 84% or more after being heat-treated at 260 ° C. for 60 minutes. For this reason, this base | substrate can show favorable whiteness also in high temperature environments, such as the time of soldering of a light emitting element, and the time of use of a light emitting element.

(2)
As described above, the substrate according to the present embodiment has a resin layer, and the resin layer is composed of “a resin mainly composed of a specific polyimide resin” and “a filler mainly composed of a white pigment”. ing. For this reason, this resin layer can have characteristics inherent to both components, such as electrical insulation, solvent resistance, and weather resistance.

<Examples and Comparative Examples>
EXAMPLES Hereinafter, although this invention is demonstrated more concretely using an Example and a comparative example, this invention is not limited by these Examples.

Prior to the introduction of Examples and Comparative Examples, synthesis examples of polyimide precursor solutions used in Examples and Comparative Examples are introduced below.
(Synthesis Example 1)
13.06 g of 4,4′-diaminodiphenylsulfone (44DDS), 11.95 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 2,2′-bis (4- A polyimide precursor solution A was obtained by reacting 7.05 g of phenoxyphenyl) propanetetracarboxylic dianhydride (BPADA) in 67.95 g of N, N-dimethylacetamide (DMAC). The solid content concentration of the polyimide precursor solution A was 30% by mass. Has a glass transition temperature at 315 ° C. The glass transition temperature is specified from a chart obtained by using a dynamic viscoelasticity measuring device (DMS6100) manufactured by Seiko Instruments Inc. and raising the temperature to 350 ° C. at 2 ° C./min at a measurement frequency of 1 Hz.

(Synthesis Example 2)
44 DDS 11.65 g, BPDA 5.69 g, BPADA 10.06 g and 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) 4.29 g were reacted in DMAC 68.31 g. By doing so, a polyimide precursor solution B was obtained. The solid content concentration of the polyimide precursor solution B was 30% by mass. Moreover, when the glass transition temperature of the polyimide resin B obtained by imidizing the polyimide precursor in the polyimide precursor solution B was determined by the same method as shown in Synthesis Example 1, the value was 299 ° C. Met.

(Synthesis Example 3)
A polyimide precursor solution C was obtained by reacting 14.71 g of 3,3′-diaminodiphenylsulfone (33DDS) and 17.43 g of BPDA in 67.87 g of DMAC. The solid content concentration of the polyimide precursor solution C was 30% by mass. Moreover, when the glass transition temperature of the polyimide resin C obtained by imidizing the polyimide precursor in this polyimide precursor solution C was calculated | required by the method similar to the method shown by the synthesis example 1, the value is 276 degreeC. Met.

(Synthesis Example 4)
44DDS 14.71 g and BPDA 17.43 g were reacted in DMAC 67.87 g to obtain a polyimide precursor solution D. The solid content concentration of the polyimide precursor solution D was 30% by mass. Moreover, when the glass transition temperature of the polyimide resin D obtained by imidizing the polyimide precursor in this polyimide precursor solution D was calculated | required by the method similar to the method shown by the synthesis example 1, the value is 361 degreeC. Met.

(Synthesis Example 5)
A polyimide precursor solution E was obtained by reacting 18.82 g of bis [4- (3-aminophenoxy) phenyl] sulfone (BAPSM) with 12.74 g of BPDA in 68.44 g of DMAC. The solid content concentration of the polyimide precursor solution E was 30% by mass. Moreover, when the glass transition temperature of the polyimide resin E obtained by imidizing the polyimide precursor in the polyimide precursor solution E was determined by the same method as that shown in Synthesis Example 1, the value was 248 ° C. Met.

(Synthesis Example 6)
First, 14.71 g of 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride (a-BPDA) was dissolved in 100 g of NMP to prepare an NMP solution of a-BPDA. Next, 30.803 g of diaminopolysiloxane (DAPS) was dissolved in 100 g of methyl diglyme to prepare a methyl diglyme solution of DAPS. Further, 3.078 g of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) and 1.114 g of 3,5-diaminobenzoic acid (DABA) were dissolved in 47.9 g of NMP to obtain BAPP. / DABA NMP solution was prepared.

  First, a methyl diglyme solution of DAPS and an NMP solution of a-BPDA were mixed, and a polymerization reaction was performed at 190 ° C. for 4 hours while passing nitrogen gas through the mixed solution. Thereafter, the polymerization solution was returned to room temperature and stirred, and an NMP solution of BAPP / DABA was added to the polymerization solution to carry out a polymerization reaction at 200 ° C. for 3 hours. After the completion of the polymerization reaction, the polymerization solution was added to methanol to precipitate a polymer powder. The polymer powder was filtered off from the polymer powder deposit, and the polymer powder was washed twice with methanol. Finally, the polymer powder was vacuum dried at 60 ° C. for 8 hours to obtain polyimide siloxane powder F.

(Synthesis Example 7)
A polyimidesiloxane powder G was obtained in the same manner as in Synthesis Example 6 except that the amount of BAPP added was changed to 4.015 g and the amount of DABA added was changed to 0.761 g.

(Synthesis Example 8)
First, 147.2 g of a-BPDA was dissolved in 1274 g of NMP to prepare an NMP solution of a-BPDA. Next, 304.9 g of DAPS was dissolved in 530 g of methyl diglyme to prepare a methyl diglyme solution of DAPS. Further, BAPP 62.19 g was dissolved in NMP 500 g to prepare an NMP solution of BAPP.

  First, a methyl diglyme solution of DAPS and an NMP solution of a-BPDA were mixed, and a polymerization reaction was performed at 190 ° C. for 3 hours while passing nitrogen gas through the mixed solution. Thereafter, the polymerization solution was once returned to room temperature and stirred, an NMP solution of BAPP was added to the polymerization solution, and a polymerization reaction was performed at 200 ° C. for 6 hours. After the completion of the polymerization reaction, the polymerization solution was added to methanol to precipitate a polymer powder. The polymer powder was filtered off from the polymer powder deposit, and the polymer powder was washed twice with methanol. Finally, the polymer powder was vacuum dried at 60 ° C. for 8 hours to obtain polyimide siloxane powder H.

1. Formation of Resin Layer 10.45 g of rutile titanium oxide (average particle size 0.21 μm, oil absorption 15 g / 100 g, specific gravity 4.3) is added as a filler to 45 g of the polyimide precursor solution A obtained in Synthesis Example 1. Thus, a filler-containing polyimide precursor solution was obtained.

The filler-containing polyimide precursor solution was applied to an aluminum plate having a length of 100 mm, a width of 100 mm, and a thickness of 0.3 mm. Next, the coating film was heated at 80 ° C. for 20 minutes and at 120 ° C. for 20 minutes, and then the heating temperature was further increased from 120 ° C. to 300 ° C. over 40 minutes and baked at 300 ° C. for 2 minutes. As a result, a resin layer having a thickness of 24 μm was formed on the aluminum plate. In addition, content of the filler in a resin layer was 43.4 mass% (20 volume%).
2. Various physical properties of the resin layer The initial hunter whiteness, initial total light reflectance, initial spectral reflectance, and dielectric breakdown strength of the obtained resin layer were determined as follows. Further, here, changes in the Hunter whiteness, total light reflectance, and spectral reflectance over time when the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C. were verified.

(1) Initial Hunter Whiteness The Hunter whiteness of the resin layer was determined in a wavelength range from 400 nm to 700 nm using a Minolta precision color difference meter (CM-3500D). The initial Hunter whiteness of the resin layer according to this example was 89.25% (see Table 1).

(2) Total light reflectance The total light reflectance of the resin layer was calculated | required in the wavelength range from 400 nm to 700 nm using the Minolta precision color difference meter (CM-3500D). The resin layer according to this example had an initial total light reflectance of 80.99% (see Table 2).

(3) Spectral reflectance The spectral reflectance of the resin layer at a wavelength of 470 nm was determined using a Minolta precision color difference meter (CM-3500D). The initial spectral reflectance of the resin layer according to this example was 80.09% (see Table 3).

(4) Dielectric breakdown strength A voltage was applied to the resin layer up to 5 kV in 30 seconds, and the voltage at which dielectric breakdown occurred was read. And the value which converted the voltage per thickness of 1 mm of the resin layer was made into the dielectric breakdown strength. The dielectric breakdown strength of the resin layer according to this example was 117.1 kV / mm.

(5) Verification of hunter whiteness, total light reflectance and spectral reflectance over time when exposed to a temperature environment of 260 ° C. The laminate of the aluminum plate and the resin layer is exposed to a temperature environment of 260 ° C. for 10 minutes. The hunter whiteness, total light reflectance, and spectral reflectance of the resin layer were determined at the elapsed time, 1 hour, 2 hours, 12 hours, and 24 hours.

  In addition, when a light emitting element is soldered to such a laminated body, the laminated body can be normally heated at about 260 degreeC for about 10 minutes. Therefore, such a laminate is often required to have such heat resistance. That is, the solder heat resistance of this resin layer can be evaluated by data at the time when 10 minutes have passed. Further, when the light emitting element is used after the light emitting element is mounted on such a stacked body, the stacked body may be heated to about 150 ° C. by light or heat emitted from the light emitting element. Therefore, such a laminate is required to maintain good whiteness under heating at about 150 ° C. For this reason, although the heat resistance of the resin layer at the time of use of a light emitting element is normally evaluated at about 150 degreeC, it is evaluated at 260 degreeC here in order to shorten evaluation time.

  The Hunter whiteness of the resin layer after 10 minutes was 88.18%, the Hunter whiteness after 1 hour was 88.55%, and the Hunter whiteness after 2 hours was 88.07. %, Hunter whiteness after 12 hours was 86.85%, and Hunter whiteness after 24 hours was 86.04% (see Table 1).

  Further, when the ratio of the hunter whiteness to the initial hunter whiteness at each time point, that is, the maintenance ratio of the hunter whiteness was determined, the maintenance ratio at the time of 10 minutes was 98.80%, and one hour passed The maintenance rate at the time is 99.22%, the maintenance rate at the time of 2 hours is 98.68%, the maintenance rate at the time of 12 hours is 97.31%, and the maintenance rate at the time of 24 hours The rate was 96.40% (see Table 1).

  Further, the total light reflectance at the time when 10 minutes passed was 79.15%, the total light reflectance at 1 hour elapsed was 80.49%, and the total light reflection after 2 hours elapsed. The rate was 80.10%, the total light reflectance after 12 hours was 79.07%, and the total light reflectance after 24 hours was 77.61% (see Table 2).

  In addition, when the ratio of the total light reflectance at each time elapsed to the initial total light reflectance, that is, the maintenance ratio of the total light reflectance was determined, the maintenance ratio at the time of 10 minutes was 97.73%, The maintenance rate after 1 hour is 99.38%, the maintenance rate after 2 hours is 98.90%, the maintenance rate after 12 hours is 97.63%, and the maintenance time is 24 hours. The maintenance rate was 95.83% (see Table 2).

  Further, the spectral reflectance at the time when 10 minutes have elapsed from the resin layer is 77.53%, the spectral reflectance at the time after 1 hour is 78.05%, and the spectral reflectance at the time after 2 hours is 76%. The spectral reflectance at a time point of 90% and 12 hours was 74.13%, and the spectral reflectance at a time point of 24 hours was 72.47% (see Table 3).

  Further, when the ratio of the spectral reflectance to the initial spectral reflectance at each time point, that is, the maintenance ratio of the spectral reflectance was obtained, the maintenance ratio at 10 minutes was 96.80%, and one hour passed. The maintenance rate at the time is 97.45%, the maintenance rate at the time of 2 hours is 96.02%, the maintenance rate at the time of 12 hours is 92.56%, and the maintenance rate is at the time of 24 hours The rate was 90.49% (see Table 3).

(6) Verification of time-dependent changes in Hunter whiteness, total light reflectance and spectral reflectance when exposed to a temperature environment of 280 ° C. 30 minutes by exposing the laminate of the aluminum plate and the resin layer to a temperature environment of 280 ° C. The hunter whiteness, total light reflectance, and spectral reflectance of the resin layer at the time were determined.

  The Hunter whiteness of the resin layer after 30 minutes was 88.16%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 98.78% (see Table 4).

  Moreover, the total light reflectance in 30 minutes progress of a resin layer was 80.04%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 98.83% (see Table 5).

  The spectral reflectance of the resin layer after 30 minutes was 77.10%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 96.27% (see Table 6).

  A resin layer was formed in the same manner as in Example 1 except that the filler was changed to rutile type titanium oxide (average particle size 0.25 μm, oil absorption 17 g / 100 g, specific gravity 4.3). The resin layer had a thickness of 23 μm.

  Then, in the same manner as in Example 1, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined, the initial hunter whiteness of this resin layer was 89.65%. (See Table 1), the initial total light reflectance is 82.75% (see Table 2), the initial spectral reflectance is 80.43% (see Table 3), and the dielectric breakdown strength is 180.7 kV. / Mm.

  In the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., 10 minutes elapsed time, 1 hour elapsed time, 2 hours elapsed time, 12 hours elapsed time and 24 hours. When the Hunter whiteness, total light reflectance, and spectral reflectance of the resin layer at the time were determined, the following results were obtained.

  The hunter whiteness after 10 minutes of the resin layer was 88.55%, the hunter whiteness after 1 hour was 87.84%, and the hunter whiteness after 2 hours was 87.10. %, Hunter whiteness after 12 hours was 85.48%, and Hunter whiteness after 24 hours was 85.17% (see Table 1).

  Moreover, when the maintenance rate of the hunter whiteness at each time point was determined, the maintenance rate after 10 minutes was 98.77%, and the maintenance rate after 1 hour was 97.98%. The maintenance rate after 2 hours was 97.16%, the maintenance rate after 12 hours was 95.35%, and the maintenance rate after 24 hours was 95.00% (Table 1). reference).

  In addition, the total light reflectance at the time when 10 minutes have elapsed from the resin layer is 82.07%, the total light reflectance at the time after 1 hour is 80.91%, and the total light reflection at the time when 2 hours have elapsed. The rate was 80.17%, the total light reflectance after 12 hours was 78.31%, and the total light reflectance after 24 hours was 78.46% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was obtained, the maintenance rate at the time point of 10 minutes was 99.18%, and the maintenance factor at the time point of 1 hour was 97.78%. Yes, the maintenance rate at the time of 2 hours was 96.88%, the maintenance rate at the time of 12 hours was 94.63%, and the maintenance rate at the time of 24 hours was 94.82% (Table 2).

  Further, the spectral reflectance at the time when 10 minutes elapses of the resin layer is 77.52%, the spectral reflectance at the time of 1 hour is 75.90%, and the spectral reflectance at the time of 2 hours is 74. .18%, the spectral reflectance after 12 hours was 70.66%, and the spectral reflectance after 24 hours was 70.18% (see Table 3).

  Further, when the maintenance ratio of the spectral reflectance at each time passage was obtained, the maintenance ratio at the passage of 10 minutes was 96.38%, and the maintenance ratio at the passage of 1 hour was 94.37%. The maintenance rate after 2 hours was 92.23%, the maintenance rate after 12 hours was 87.85%, and the maintenance rate after 24 hours was 87.26% (Table 3). reference).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 86.95%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 9699% (see Table 4).

  Moreover, the total light reflectivity of the resin layer after 30 minutes was 79.92%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 96.58% (see Table 5).

  The spectral reflectance of the resin layer after 30 minutes was 73.75%. Moreover, when the maintenance factor of the spectral reflectance at the same point was determined, the maintenance factor was 91.69% (see Table 6).

  Furthermore, in this example, the temporal change of Hunter whiteness, total light reflectance, and spectral reflectance when exposed to a temperature environment of 150 ° C. was also verified. Specifically, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 150 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 392 hours elapsed were obtained. At this time, the initial Hunter whiteness of the resin layer is 90.00% (see Table 7), the initial total light reflectance is 83.46% (see Table 8), and the initial spectral reflectance is 81.46. 05% (see Table 9).

  The Hunter whiteness of the resin layer after 392 hours was 88.69% (see Table 7).

  Further, the ratio of the hunter whiteness to the initial hunter whiteness at the time of 392 hours, that is, the maintenance ratio of the hunter whiteness was determined to be 98.55% (see Table 7).

  Further, the total light reflectance of the resin layer at the time of 392 hours was 81.82% (see Table 8).

  Further, the ratio of the total light reflectance to the initial total light reflectance at the time of 392 hours, that is, the maintenance ratio of the total light reflectance was determined to be 98.03% (see Table 8).

  The spectral reflectance of the resin layer after 392 hours was 78.27% (see Table 9).

  Further, when the ratio of the spectral reflectance to the initial spectral reflectance at the time of 392 hours, that is, the maintenance ratio of the spectral reflectance was obtained, it was 96.58% (see Table 9).

  A resin layer was formed in the same manner as in Example 2 except that the final baking temperature was changed to 270 ° C. The resin layer had a thickness of 26 μm.

  Then, in the same manner as in Example 1, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined, the initial hunter whiteness of this resin layer was 90.85%. (See Table 1), the initial total light reflectance is 84.55% (see Table 2), the initial spectral reflectance is 83.45% (see Table 3), and the dielectric breakdown strength is 131.2 kV. / Mm.

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., and the hunter whiteness, total light reflectance and the resin layer after 10 minutes and 1 hour had elapsed. When the spectral reflectance was determined, the following results were obtained.

  The hunter whiteness after 10 minutes of the resin layer was 90.10%, and the hunter whiteness after 1 hour was 89.21% (see Table 1).

  Further, when the maintenance ratio of Hunter whiteness at each time point was determined, the maintenance ratio at the time point of 10 minutes was 99.17%, and the maintenance ratio at the time point of 1 hour was 98.19%. (See Table 1).

  Further, the total light reflectance at the time when 10 minutes had elapsed from the resin layer was 84.51%, and the total light reflectance at the time when 1 hour had elapsed was 83.90% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was determined, the maintenance rate at the time point of 10 minutes was 99.95%, and the maintenance factor at the time point of 1 hour was 99.23%. (See Table 2).

  Moreover, the spectral reflectance at the time of 10-minute progress of the resin layer was 81.32%, and the spectral reflectance at the time of 1 hour elapsed was 79.46% (see Table 3).

  Further, when the maintenance rate of the spectral reflectance at each time point was obtained, the maintenance rate at the time point after 10 minutes was 97.45%, and the maintenance factor at the time point after 1 hour was 95.22%. (See Table 3).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 88.37%. Moreover, when the maintenance rate of the hunter whiteness at the same point was determined, the maintenance rate was 97.27% (see Table 4).

  Moreover, the total light reflectivity of the resin layer after 30 minutes was 82.50%. Moreover, when the maintenance factor of the total light reflectance at the same point was determined, the maintenance factor was 97.58% (see Table 5).

The spectral reflectance of the resin layer after 30 minutes was 77.13%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 92.43% (see Table 6).
Further, in this example, as in Example 2, the change over time of Hunter whiteness, total light reflectance, and spectral reflectance when exposed to a temperature environment of 150 ° C. was also verified. Specifically, the laminate of the aluminum plate and the resin layer is exposed to a temperature environment of 150 ° C., and the hunter whiteness of the resin layer, the total light reflectance, and the time when 89 hours have elapsed, 252 hours have elapsed, and 392 hours have elapsed. Spectral reflectance was determined. At this time, the initial Hunter whiteness of the resin layer is 90.85% (see Table 7), the initial total light reflectance is 84.55% (see Table 8), and the initial spectral reflectance is 83.85%. 45% (see Table 9).

  The Hunter whiteness of the resin layer after 89 hours was 90.41%, the Hunter whiteness after 252 hours was 89.91%, and the Hunter whiteness after 392 hours was 89.50. % (See Table 7).

  Further, when the ratio of the hunter whiteness to the initial hunter whiteness at each time point, that is, the maintenance ratio of the hunter whiteness was determined, the maintenance ratio at 89 hours was 99.52%, and 252 hours passed. The maintenance rate at the time was 98.96%, and the maintenance rate at the time of 392 hours was 98.51% (see Table 7).

  Further, the total light reflectivity at the time when 89 hours have elapsed is 83.96%, the total light reflectivity at the time when 252 hours have elapsed is 84.30%, and the total light reflection when 392 hours have elapsed. The rate was 84.72% (see Table 8).

  Further, when the ratio of the total light reflectance at each time passage time to the initial total light reflectance, that is, the maintenance ratio of the total light reflectance was determined, the maintenance ratio at the time of 89 hours was 99.30%, The maintenance rate after 252 hours was 99.70%, and the maintenance rate after 392 hours was 100.20% (see Table 8).

  The spectral reflectance of the resin layer after 89 hours is 82.55%, the spectral reflectance after 252 hours is 81.29%, and the spectral reflectance after 392 hours is 80%. 60% (see Table 9).

  Further, when the ratio of the spectral reflectance to the initial spectral reflectance at each time point, that is, the maintenance ratio of the spectral reflectance was obtained, the maintenance ratio at 89 hours was 98.92%, and 252 hours passed. The maintenance rate at the time point was 97.41%, and the maintenance rate at the time point of 392 hours was 96.58% (see Table 9).

  A resin layer was formed in the same manner as in Example 2 except that the amount of filler added was changed to 4.60 g. The resin layer had a thickness of 26 μm. Moreover, content of the filler in a resin layer was 25.4 mass% (10 volume%).

  Then, in the same manner as in Example 1, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined, the initial hunter whiteness of this resin layer was 85.92%. (See Table 1), the initial total light reflectance is 75.01% (see Table 2), the initial spectral reflectance is 73.85% (see Table 3), and the dielectric breakdown strength is 97.2 kV. / Mm.

  In the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., 10 minutes elapsed time, 1 hour elapsed time, 2 hours elapsed time, 12 hours elapsed time and 24 hours. When the Hunter whiteness, total light reflectance, and spectral reflectance of the resin layer at the time were determined, the following results were obtained.

  The Hunter whiteness after 10 minutes of the resin layer was 86.05%, the Hunter whiteness after 1 hour was 85.89%, and the Hunter whiteness after 2 hours was 85.06. %, Hunter whiteness after 12 hours was 82.77%, and Hunter whiteness after 24 hours was 82.88% (see Table 1).

  Moreover, when the maintenance rate of the hunter whiteness at each time point was determined, the maintenance rate after 10 minutes was 100.15%, and the maintenance rate after 1 hour was 99.97%. The maintenance rate after 2 hours was 99.00%, the maintenance rate after 12 hours was 96.33%, and the maintenance rate after 24 hours was 96.46% (Table 1). reference).

  Further, the total light reflectance at the time when 10 minutes passed was 76.13%, the total light reflectance at 1 hour was 76.33%, and the total light reflection after 2 hours. The rate was 74.99%, the total light reflectance after 12 hours was 71.96%, and the total light reflectance after 24 hours was 73.85% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was calculated, the maintenance rate at the time point of 10 minutes was 101.49%, and the maintenance factor at the time point of 1 hour was 101.76%. Yes, the maintenance rate after 2 hours was 99.97%, the maintenance rate after 12 hours was 95.93%, and the maintenance rate after 24 hours was 98.45% (Table 2).

  Further, the spectral reflectance at the time when 10 minutes have elapsed from the resin layer is 73.89%, the spectral reflectance at the time after 1 hour is 72.98%, and the spectral reflectance at the time after 2 hours is 71. The spectral reflectance after 10 hours at 12 hours was 66.21%, and the spectral reflectance after 24 hours was 66.28% (see Table 3).

  Further, when the maintenance ratio of the spectral reflectance at each time passage was determined, the maintenance ratio at the passage of 10 minutes was 99.51%, and the maintenance ratio at the passage of 1 hour was 98.82%. The maintenance rate after 2 hours was 96.28%, the maintenance rate after 12 hours was 89.65%, and the maintenance rate after 24 hours was 89.75% (Table 3). reference).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 84.85%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 98.75% (see Table 4).

  Moreover, the total light reflectivity of the resin layer after 30 minutes was 74.07%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 98.75% (see Table 5).

  Further, the spectral reflectance after 30 minutes of the resin layer was 70.87%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 95.96% (see Table 6).

  A resin layer was formed in the same manner as in Example 2 except that the amount of filler added was changed to 17.68 g. The resin layer had a thickness of 38 μm. Moreover, content of the filler in a resin layer was 56.7 mass% (30 volume%).

  Then, in the same manner as in Example 1, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined, the initial hunter whiteness of this resin layer was 90.17%. (See Table 1), the initial total light reflectance is 85.14% (see Table 2), the initial spectral reflectance is 80.53% (see Table 3), and the dielectric breakdown strength is 98.2 kV. / Mm.

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., and the hunter whiteness, total light reflectance and the resin layer after 10 minutes and 1 hour had elapsed. When the spectral reflectance was determined, the following results were obtained.

  The Hunter whiteness of the resin layer after 10 minutes was 89.32%, and the Hunter whiteness after 1 hour was 88.68% (see Table 1).

  Further, when the maintenance ratio of Hunter whiteness at each time point was obtained, the maintenance ratio at the time point of 10 minutes was 99.06%, and the maintenance ratio at the time point of 1 hour was 98.35%. (See Table 1).

  In addition, the total light reflectance at the time when 10 minutes passed through the resin layer was 84.19%, and the total light reflectance at the time when 1 hour had elapsed was 83.47% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was determined, the maintenance rate at the time point of 10 minutes was 98.88%, and the maintenance factor at the time point of 1 hour was 98.04%. (See Table 2).

  Moreover, the spectral reflectance at the time of 10-minute progress of the resin layer was 78.31%, and the spectral reflectance at the time of 1 hour elapsed was 77.06% (see Table 3).

  Further, when the maintenance rate of the spectral reflectance at each time point was obtained, the maintenance rate at the time point after 10 minutes was 97.24%, and the maintenance factor at the time point after 1 hour was 95.69%. (See Table 3).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 87.69%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 97.25% (see Table 4).

  Moreover, the total light reflectivity at the time of 30-minute progress of the resin layer was 81.40%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 95.61% (see Table 5).

  Further, the spectral reflectance of the resin layer after 30 minutes was 74.47%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 92.47% (see Table 6).

  A resin layer was formed in the same manner as in Example 2 except that the polyimide precursor solution A was replaced with the polyimide precursor solution B obtained in Synthesis Example 2. The resin layer had a thickness of 33 μm.

  Then, in the same manner as in Example 1, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined, the initial hunter whiteness of this resin layer was 91.30%. (See Table 1), the initial total light reflectance is 86.27% (see Table 2), the initial spectral reflectance is 83.17% (see Table 3), and the dielectric breakdown strength is 121.5 kV. / Mm.

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., and the hunter whiteness, total light reflectance and the resin layer after 10 minutes and 1 hour had elapsed. When the spectral reflectance was determined, the following results were obtained.

  The hunter whiteness after 10 minutes of the resin layer was 90.61%, and the hunter whiteness after 1 hour was 90.08% (see Table 1).

  Further, when the maintenance ratio of Hunter whiteness at each time point was determined, the maintenance ratio at the time point of 10 minutes was 99.24%, and the maintenance ratio at the time point of 1 hour was 98.66%. (See Table 1).

  Moreover, the total light reflectivity at the time of 10-minute progress of the resin layer was 85.59%, and the total light reflectivity at the time of 1 hour was 85.05% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was obtained, the maintenance rate at the time point of 10 minutes was 99.21%, and the maintenance factor at the time point of 1 hour was 98.59%. (See Table 2).

  Moreover, the spectral reflectance at the time of 10-minute progress of the resin layer was 81.48%, and the spectral reflectance at the time of 1 hour elapsed was 80.43% (see Table 3).

  Further, when the maintenance ratio of the spectral reflectance at each time point was obtained, the maintenance ratio at the time point of 10 minutes was 97.97%, and the maintenance ratio at the time point of 1 hour was 96.71%. (See Table 3).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 89.38%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 97.90% (see Table 4).

  Moreover, the total light reflectivity of the resin layer after 30 minutes was 84.06%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 97.44% (see Table 5).

  The spectral reflectance of the resin layer after 30 minutes was 78.43%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 94.30% (see Table 6).

  A resin layer was formed in the same manner as in Example 3 except that the polyimide precursor solution A was replaced with the polyimide precursor solution C obtained in Synthesis Example 3. The resin layer had a thickness of 34 μm.

  Then, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined in the same manner as in Example 1, the initial hunter whiteness of this resin layer was 92.28%. (See Table 1), the initial total light reflectance is 86.69% (see Table 2), the initial spectral reflectance is 85.05% (see Table 3), and the dielectric breakdown strength is 114.0 kV. / Mm.

  In the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., 10 minutes elapsed time, 1 hour elapsed time, 2 hours elapsed time, 12 hours elapsed time and 24 hours. When the Hunter whiteness, total light reflectance, and spectral reflectance of the resin layer at the time were determined, the following results were obtained.

  The Hunter whiteness at the time of 10 minutes of the resin layer was 91.18%, the Hunter whiteness at the time of 1 hour was 88.84%, and the Hunter whiteness at the time of 2 hours was 87.87. %, Hunter whiteness after 12 hours was 85.36%, and Hunter whiteness after 24 hours was 84.42% (see Table 1).

  Moreover, when the maintenance rate of the hunter whiteness at each time point was determined, the maintenance rate after 10 minutes was 98.81%, and the maintenance rate after 1 hour was 96.27%. The maintenance rate after 2 hours was 95.22%, the maintenance rate after 12 hours was 92.50%, and the maintenance rate after 24 hours was 91.48% (Table 1). reference).

  In addition, the total light reflectance at the time when the resin layer 10 minutes passed was 85.08%, the total light reflectance at the time 1 hour passed was 82.04%, and the total light reflection after the time 2 hours passed. The rate was 80.88%, the total light reflectance after 12 hours was 77.80%, and the total light reflectance after 24 hours was 76.74% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was determined, the maintenance rate at the time point of 10 minutes was 98.14%, and the maintenance factor at the time point of 1 hour was 94.64%. Yes, the maintenance rate after 2 hours was 93.30%, the maintenance rate after 12 hours was 89.75%, and the maintenance rate after 24 hours was 88.52% (Table 2).

  Further, the spectral reflectance after 10 minutes of the resin layer was 82.24%, the spectral reflectance after 1 hour was 76.50%, and the spectral reflectance after 2 hours was 74. The spectral reflectance at the time point of .28% and 12 hours was 69.03%, and the spectral reflectance at the time point of 24 hours was 67.06% (see Table 3).

  Further, when the maintenance ratio of the spectral reflectance at each time passage was determined, the maintenance ratio at the passage of 10 minutes was 96.70%, and the maintenance ratio at the passage of 1 hour was 89.95%. The maintenance rate after 2 hours was 87.34%, the maintenance rate after 12 hours was 81.16%, and the maintenance rate after 24 hours was 78.85% (Table 3). reference).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 88.77%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 96.20% (see Table 4).

  Moreover, the total light reflectivity of the resin layer after 30 minutes was 81.77%. Moreover, when the maintenance factor of the total light reflectance at the same point was determined, the maintenance factor was 94.32% (see Table 5).

  The spectral reflectance of the resin layer after 30 minutes was 76.27%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 89.68% (see Table 6).

  A resin layer was formed in the same manner as in Example 3 except that the polyimide precursor solution A was replaced with the polyimide precursor solution D obtained in Synthesis Example 4. The resin layer had a thickness of 28 μm.

  Then, the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined in the same manner as in Example 1. The initial hunter whiteness of this resin layer was 90.37%. (See Table 1), the initial total light reflectance is 85.42% (see Table 2), the initial spectral reflectance is 82.91% (see Table 3), and the dielectric breakdown strength is 115.8 kV. / Mm.

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., and the hunter whiteness, total light reflectance and the resin layer after 10 minutes and 1 hour had elapsed. When the spectral reflectance was determined, the following results were obtained.

  The Hunter whiteness of the resin layer after 10 minutes was 89.98%, and the Hunter whiteness after 1 hour was 88.38% (see Table 1).

  Further, when the maintenance ratio of Hunter whiteness at each time point was determined, the maintenance ratio after 10 minutes was 99.57%, and the maintenance ratio after one hour was 97.80%. (See Table 1).

  Moreover, the total light reflectivity at the time of 10-minute progress of the resin layer was 84.91%, and the total light reflectivity at the time of 1 hour elapsed was 83.06% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was obtained, the maintenance rate at the time point of 10 minutes was 99.40%, and the maintenance factor at the time point of 1 hour was 97.24%. (See Table 2).

  The spectral reflectance of the resin layer at the time when 10 minutes passed was 81.84%, and the spectral reflectance at the time of 1 hour was 77.69% (see Table 3).

  Further, when the maintenance ratio of the spectral reflectance at each time point was obtained, the maintenance ratio after 10 minutes was 98.71%, and the maintenance ratio after one hour was 93.70%. (See Table 3).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 88.00%. Moreover, when the maintenance rate of the hunter whiteness at the same point was determined, the maintenance rate was 97.38% (see Table 4).

  Moreover, the total light reflectance in 30 minutes progress of a resin layer was 81.83%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 95.80% (see Table 5).

  The spectral reflectance of the resin layer after 30 minutes was 76.28%. Moreover, when the maintenance factor of the spectral reflectance at the same point was determined, the maintenance factor was 92.00% (see Table 6).

  A resin layer was formed in the same manner as in Example 3 except that the polyimide precursor solution A was replaced with the polyimide precursor solution E obtained in Synthesis Example 5. The resin layer had a thickness of 34 μm.

  Then, in the same manner as in Example 1, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin layer were determined, the initial hunter whiteness of this resin layer was 89.72%. (See Table 1), the initial total light reflectance is 83.21% (see Table 2), the initial spectral reflectance is 81.43% (see Table 3), and the dielectric breakdown strength is 103.2 kV. / Mm.

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 260 ° C., and the hunter whiteness, total light reflectance and the resin layer after 10 minutes and 1 hour had elapsed. When the spectral reflectance was determined, the following results were obtained.

  The Hunter whiteness of the resin layer after 10 minutes was 89.15%, and the Hunter whiteness after 1 hour was 88.29% (see Table 1).

  Further, when the maintenance ratio of Hunter whiteness at each time point was determined, the maintenance ratio after 10 minutes was 99.36%, and the maintenance ratio after 1 hour was 98.41%. (See Table 1).

  Moreover, the total light reflectivity at the time of 10-minute progress of the resin layer was 82.08%, and the total light reflectivity at the time of 1 hour elapsed was 81.31% (see Table 2).

  Further, when the maintenance ratio of the total light reflectance at each time point was obtained, the maintenance ratio after 10 minutes was 98.64%, and the maintenance ratio after one hour was 97.72%. (See Table 2).

  The spectral reflectance of the resin layer after 10 minutes was 80.14%, and the spectral reflectance after 1 hour was 78.05% (see Table 3).

  Further, when the maintenance ratio of the spectral reflectance at each time point was determined, the maintenance ratio after 10 minutes was 98.42%, and the maintenance ratio after one hour was 95.85%. (See Table 3).

  Further, in the same manner as in Example 1, the laminate of the aluminum plate and the resin layer was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer after 30 minutes were obtained. As a result, the following results were obtained.

  The Hunter whiteness of the resin layer after 30 minutes was 87.96%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 98.04% (see Table 4).

  Moreover, the total light reflectivity of the resin layer after 30 minutes was 81.23%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 97.62% (see Table 5).

  The spectral reflectance of the resin layer after 30 minutes was 76.84%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 94.36% (see Table 6).

  A resin layer was formed in the same manner as in Example 2 except that the aluminum plate was replaced with a glass plate. And the resin layer was peeled from the glass plate and the resin film was formed. The resin film had a thickness of 30 μm.

  Then, in the same manner as in Example 1, when the initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin film were determined, the initial hunter whiteness of this resin film was 91.19%. (See Table 1), the initial total light reflectance was 85.29% (see Table 2), and the initial spectral reflectance was 83.92% (see Table 3).

  Further, in the same manner as in Example 1, the resin film was exposed to a temperature environment of 260 ° C., 1 hour elapsed time, 2 hours elapsed time, 12 hours elapsed time and 24 hours elapsed time, When the light reflectance and the spectral reflectance were determined, the following results were obtained.

  The Hunter whiteness of the resin film after 1 hour is 90.12%, the Hunter whiteness after 2 hours is 88.67%, and the Hunter whiteness after 12 hours is 86.49%. Yes, the Hunter whiteness at the time of 24 hours was 86.03% (see Table 1).

  Further, when the maintenance rate of Hunter whiteness at each time point was determined, the maintenance rate at the time point of 1 hour was 98.83%, and the maintenance rate at the time point of 2 hours was 97.24%, 12%. The maintenance rate at the time point was 94.85%, and the maintenance rate at the time point of 24 hours was 94.34% (see Table 1).

  Moreover, the total light reflectivity at the time of 1 hour passage of the resin film is 84.52%, the total light reflectivity at the time of passage of 2 hours is 83.24%, and the total light reflectivity at the time of passage of 12 hours is It was 80.61%, and the total light reflectance after 24 hours was 80.3% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was determined, the maintenance rate at the time point of 1 hour was 90.10%, and the maintenance rate at the time point of 2 hours was 97.60%, The maintenance rate after 12 hours was 94.51%, and the maintenance rate after 24 hours was 94.07% (see Table 2).

  The spectral reflectance of the resin film after 1 hour was 81.39%, the spectral reflectance after 2 hours was 78.01%, and the spectral reflectance after 12 hours was 72.95. %, And the spectral reflectance after 24 hours was 72.35% (see Table 3).

  Further, when the maintenance rate of the spectral reflectance at each time point was determined, the maintenance rate at the time point of 1 hour was 96.99%, and the maintenance rate at the time point of 2 hours was 92.96%, 12%. The maintenance rate at the time point was 86.93%, and the maintenance rate at the time point of 24 hours was 86.21% (see Table 3).

  Further, in the same manner as in Example 1, the resin film was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance and spectral reflectance of the resin film after 30 minutes were determined. Got.

  The Hunter whiteness of the resin film after 30 minutes was 89.68%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 98.34% (see Table 4).

  Further, the total light reflectance of the resin film after 30 minutes was 83.94%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 98.42% (see Table 5).

  The spectral reflectance of the resin film after 30 minutes was 80.05%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 95.39% (see Table 6).

  A resin layer was formed in the same manner as in Example 10 except that the filler-containing polyimide precursor solution used in Example 2 was applied so that the resin layer had a thickness of 38 μm. And the resin layer was peeled from the glass plate and the resin film was formed. The resin film had a thickness of 38 μm.

  The initial hunter whiteness, initial total light reflectance, initial spectral reflectance and dielectric breakdown strength of this resin film were determined in the same manner as in Example 1. The initial hunter whiteness of this resin film was 91.28%. (See Table 1), the initial total light reflectance was 86.73% (see Table 2), and the initial spectral reflectance was 83.86% (see Table 3).

  Further, in the same manner as in Example 1, the resin film was exposed to a temperature environment of 260 ° C., 1 hour elapsed time, 2 hours elapsed time, 12 hours elapsed time and 24 hours elapsed time, When the light reflectance and the spectral reflectance were determined, the following results were obtained.

  The Hunter whiteness of the resin film after 1 hour is 90.06%, the Hunter whiteness after 2 hours is 88.64%, and the Hunter whiteness after 12 hours is 86.54%. Yes, the Hunter whiteness at the time of 24 hours was 86.08% (see Table 1).

  Moreover, when the maintenance rate of the hunter whiteness at each time point was determined, the maintenance rate after 1 hour was 98.66%, and the maintenance rate after 2 hours was 97.11%, 12 hours. The maintenance rate at the time point was 94.81%, and the maintenance rate at the time point of 24 hours was 94.30% (see Table 1).

  In addition, the total light reflectivity at the time of 1 hour of the resin film is 85.20%, the total light reflectivity at the time of 2 hours is 83.85%, and the total light reflectivity at the time of 12 hours is It was 81.88%, and the total light reflectance after 24 hours was 80.24% (see Table 2).

  Further, when the maintenance rate of the total light reflectance at each time point was obtained, the maintenance rate at the time point of 1 hour was 98.24%, and the maintenance rate at the time point of 2 hours was 96.68%, 12 The maintenance rate at the time point was 94.41%, and the maintenance rate at the time point of 24 hours was 92.52% (see Table 2).

  The spectral reflectance of the resin film after 1 hour was 81.26%, the spectral reflectance after 2 hours was 77.96%, and the spectral reflectance after 12 hours was 73.11. %, And the spectral reflectance after 24 hours was 72.42% (see Table 3).

  Further, when the maintenance ratio of the spectral reflectance at each time point was obtained, the maintenance ratio at the time point of 1 hour was 96.90%, and the maintenance ratio at the time point of 2 hours was 92.96%, 12 hours. The maintenance rate at the time point was 87.18%, and the maintenance rate at the time point of 24 hours was 86.36% (see Table 3).

  Further, in the same manner as in Example 1, the resin film was exposed to a temperature environment of 280 ° C., and the hunter whiteness, total light reflectance and spectral reflectance of the resin film after 30 minutes were determined. Got.

  The Hunter whiteness of the resin film after 30 minutes was 89.60%. Moreover, when the maintenance rate of the Hunter whiteness at the same point was determined, the maintenance rate was 98.16% (see Table 4).

  Further, the total light reflectance of the resin film after 30 minutes was 84.31%. Further, when the maintenance ratio of the total light reflectance at the same point was determined, the maintenance ratio was 97.21% (see Table 5).

  The spectral reflectance of the resin film after 30 minutes was 80.02%. Further, when the maintenance ratio of the spectral reflectance at the same point was determined, the maintenance ratio was 95.42% (see Table 6).

  2. Rutile type titanium oxide (average particle size 0.25 μm, oil absorption 17 g / 100 g, specific gravity 4.3) 5.20 g and mica (average particle size 10 μm, oil absorption 55 ml / 100 g, specific gravity 2.7) A resin layer was formed in the same manner as in Example 1 except that 25 g was used. The resin layer had a thickness of 31 μm. The content of the filler in the resin layer was 23.7% by mass (10% by volume) for rutile titanium oxide and 14.8% by mass (10% by volume) for mica.

  Then, in the same manner as in Example 2, the change over time of Hunter whiteness, total light reflectance, and spectral reflectance when exposed to a temperature environment of 150 ° C. was verified. Specifically, the laminate of the aluminum plate and the resin layer is exposed to a temperature environment of 150 ° C., and the hunter whiteness, total light reflectance, and spectral reflectance of the resin layer at the time of 252 hours and 392 hours are obtained. It was. At this time, the initial Hunter whiteness of the resin layer is 87.14% (see Table 7), the initial total light reflectance is 77.74% (see Table 8), and the initial spectral reflectance is 75.14%. 39% (see Table 9).

  The Hunter whiteness of the resin layer after 252 hours was 86.85%, and the Hunter whiteness after 392 hours was 87.08% (see Table 7).

  Further, when the ratio of the hunter whiteness to the initial hunter whiteness at each time point, that is, the maintenance ratio of the hunter whiteness was determined, the maintenance ratio at the 252 hour point was 99.67%, and 392 hours passed The maintenance rate at the time was 99.93% (see Table 7).

  Further, the total light reflectance of the resin layer after 252 hours was 77.61%, and the total light reflectance after 392 hours was 79.00% (see Table 8).

  Moreover, when the ratio of the total light reflectance at each time point to the initial total light reflectance, that is, the maintenance ratio of the total light reflectance was determined, the maintenance ratio at the time of 252 hours was 99.83%, The maintenance factor at the time of 392 hours elapsed was 101.62% (see Table 8).

  The spectral reflectance of the resin layer after 252 hours was 74.55%, and the spectral reflectance after 392 hours was 74.79% (see Table 9).

  Further, when the ratio of the spectral reflectance to the initial spectral reflectance at each time point, that is, the maintenance ratio of the spectral reflectance was obtained, the maintenance ratio at the time point of 252 hours was 98.89%, and 392 hours passed. The maintenance rate at the time was 99.20% (see Table 9).

(Comparative Example 1)
First, 100 g of polyimide siloxane powder F obtained in Synthesis Example 6 was dissolved in 163 g of methyl diglyme to prepare a methyl diglyme solution of polyimide siloxane. Next, 18 g of novolak type epoxy resin and 24 g of rutile type titanium oxide were added to the methyl diglyme solution of polyimide siloxane to obtain a filler-containing resin solution. The solid content concentration of this filler-containing resin solution was 46.6% by mass. Moreover, the viscosity at 25 ° C. of this filler-containing resin solution was 3500 centipoise.

  This filler-containing resin solution was applied to a polyimide film having a thickness of 50 μm, and the coating film was baked at 100 ° C. for 10 minutes and at 150 ° C. for 30 minutes. As a result, a resin layer having a thickness of 25 μm was formed on the polyimide film. In addition, content of the rutile type titanium oxide in a resin layer was 16.9 mass% (6.04 volume%).

  Moreover, when the laminated body of the polyimide film and the resin layer was exposed to a temperature environment of 260 ° C. in the same manner as in Example 1 and the Hunter whiteness of the resin layer at the time of 1 hour was obtained, the following results were obtained. .

  The Hunter whiteness of the resin layer after 1 hour was 78.50% (see Table 1).

(Comparative Example 2)
First, 100 g of polyimide siloxane powder G obtained in Synthesis Example 7 was dissolved in 163 g of methyl diglyme to prepare a methyl diglyme solution of polyimide siloxane. Next, 14 g of novolak type epoxy resin and 24 g of rutile type titanium oxide were added to the methyl diglyme solution of polyimide siloxane to obtain a filler-containing resin solution. The solid content concentration of this filler-containing resin solution was 45.8% by mass. Moreover, the viscosity at 25 ° C. of this filler-containing resin solution was 3800 centipoise.

  This filler-containing resin solution was applied to a polyimide film having a thickness of 50 μm, and the coating film was baked at 100 ° C. for 10 minutes and at 150 ° C. for 30 minutes. As a result, a resin layer having a thickness of 25 μm was formed on the polyimide film. In addition, content of the rutile type titanium oxide in a resin layer was 17.4 mass% (6.28 volume%).

  Moreover, when the laminated body of the polyimide film and the resin layer was exposed to a temperature environment of 260 ° C. in the same manner as in Example 1 and the Hunter whiteness of the resin layer at the time of 1 hour was obtained, the following results were obtained. .

  The Hunter whiteness of the resin layer after 1 hour was 80.10% (see Table 1).

(Comparative Example 3)
First, 100 g of polyimide siloxane powder H obtained in Synthesis Example 8 was dissolved in 163 g of methyl diglyme to prepare a methyl diglyme solution of polyimide siloxane. Next, 24 g of rutile-type titanium oxide was added to this polyimidesiloxane methyldiglyme solution to obtain a filler-containing resin solution. The solid content concentration of this filler-containing resin solution was 43.2% by mass. Further, the viscosity of the filler-containing resin solution at 25 ° C. was 2800 centipoise.

  This filler-containing resin solution was applied to a polyimide film having a thickness of 50 μm, and the coating film was baked at 100 ° C. for 10 minutes and at 150 ° C. for 30 minutes. As a result, a resin layer having a thickness of 25 μm was formed on the polyimide film. In addition, content of the rutile type titanium oxide in a resin layer was 19.4 mass% (7.29 volume%).

  Moreover, when the laminated body of the polyimide film and the resin layer was exposed to a temperature environment of 260 ° C. in the same manner as in Example 1 and the Hunter whiteness of the resin layer at the time of 1 hour was obtained, the following results were obtained. .

  The Hunter whiteness of the resin layer after 1 hour was 83.30% (see Table 1).

(Comparative Example 4)
First, 100 g of the polyimidesiloxane powder F obtained in Synthesis Example 6 was dissolved in 163 g of methyltriglyme to prepare a methyltriglyme solution of polyimidesiloxane. Next, 14 g of novolak type epoxy resin and 24 g of rutile type titanium oxide were added to the methyltriglyme solution of polyimidesiloxane to obtain a filler-containing resin solution. The solid content concentration of this filler-containing resin solution was 45.8% by mass. In addition, the viscosity of the filler-containing resin solution at 25 ° C. was 4000 centipoise.

  This filler-containing resin solution was applied to a polyimide film having a thickness of 50 μm, and the coating film was baked at 100 ° C. for 10 minutes and at 150 ° C. for 30 minutes. As a result, a resin layer having a thickness of 20 μm was formed on the polyimide film. In addition, content of the rutile type titanium oxide in a resin layer was 17.1 mass% (6.28 volume%).

  Moreover, when the laminated body of the polyimide film and the resin layer was exposed to a temperature environment of 260 ° C. in the same manner as in Example 1 and the Hunter whiteness of the resin layer at the time of 1 hour was obtained, the following results were obtained. .

  The Hunter whiteness of the resin layer after 1 hour was 78.90% (see Table 1).

  The substrate according to the present invention is characterized in that the hunter whiteness of the resin layer after heat treatment at 260 ° C. for 60 minutes is 84% or more, in particular, a circuit board for mounting a light emitting element, a cover It can be suitably used for a substrate for printing a ray or barcode.

100 Light Emitting Element Mounted Printed Circuit Board 110 White Reflective Layer (Resin Layer)
120 Light Emitting Element 130 Printed Wiring Board 200 Reflecting Plate 210 Transparent Substrate

Claims (7)

At least a resin layer containing a resin mainly composed of a polyimide resin,
The base | substrate whose Hunter whiteness of the said resin layer after heat-processing for 60 minutes at 260 degreeC is 84% or more. 2. The substrate according to claim 1, wherein the retention ratio of Hunter whiteness of the resin layer after heat treatment at 260 ° C. for 60 minutes is 93% or more. The substrate according to claim 1 or 2, wherein the total light reflectance on the resin layer side after heat treatment at 260 ° C for 60 minutes is 75% or more. The substrate according to claim 3, wherein a maintenance ratio of total light reflectance on the resin layer side after heat treatment at 260 ° C. for 60 minutes is 94% or more. The substrate according to any one of claims 1 to 4, wherein the light reflectance at 470 nm on the resin layer side after heat treatment at 260 ° C for 60 minutes is 72% or more. The substrate according to claim 5, wherein a maintenance factor of 470 nm wavelength light reflectance on the resin layer side after heat treatment at 260 ° C. for 60 minutes is 89% or more. The substrate according to claim 1, wherein the dielectric breakdown strength of the resin layer is 95 kV / mm or more.

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