JP2010275333A - White film, metal laminate and substrate for led loading - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a white film which has high reflectance in a visible light region, substantially avoids lowering of reflectance in a high temperature thermally loaded environment, and can be used for a printed wiring board for LED mounting, and to provide a metal laminate and the like. <P>SOLUTION: The white film comprises a composition containing 25-100 pts.mass of an inorganic filler based on 100 pts.mass of a resin composition containing an amorphous polyether imide resin. An average reflectance of the white film in a wavelength range of 400-800 nm is ≥70%, and a lowering rate of a reflectance at a wavelength of 470 nm after heat treatment at 200°C for 4 h is ≤10%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a white film having excellent heat resistance, reduced anisotropy, and high reflectance characteristics, a metal laminate using the white film, and an LED mounting substrate. The present invention relates to a white film or the like that is capable of mounting a light emitting diode (LED) or the like, in which a decrease in reflectance is suppressed even under a thermal load environment.

  Since chip-type LEDs that are mounted directly on the printed circuit board pattern and are resin-sealed are advantageous for miniaturization and thinning, they can be used in electronic devices such as numeric keypad lighting for mobile phones and backlights for small liquid crystal displays. Widely used.

In recent years, the improvement in the technology for increasing the brightness of LEDs has been remarkably improved, and the LEDs have become more bright, but along with this, the amount of heat generated by the LED elements themselves has increased, and the thermal load on the periphery of the printed circuit board has increased, The LED element ambient temperature is sometimes over 100 ° C. In addition, if lead (Pb) -free soldering is necessary in the manufacturing process of the LED mounting board, the reflow process may take a temperature of about 260 to 300 ° C., but there are LED mounting boards that do not require soldering. is there. Even in that case, at the time of thermosetting treatment of epoxy resin or silicone resin sealing resin, epoxy resin or silicone resin thermosetting treatment for bonding the LED chip to the substrate, wire bonding processing at about 150-200 ° C. Exposed to high temperature heat environment for several minutes to several hours. Under such heat load environment, the white printed wiring board made of the thermosetting resin composition that has been used in the past tends to deteriorate in whiteness, such as yellowing, and the reflection efficiency tends to be inferior. As a substrate, there was still room for improvement. In addition, products equipped with conventional white printed wiring boards have a tendency to deteriorate in whiteness, such as yellowing under light irradiation, particularly under ultraviolet irradiation, and have a tendency to have poor reflectance, and there is still room for improvement. . On the other hand, ceramic substrates are superior in heat resistance, but they are hard and brittle, so there is a limit to reducing the area and thickness due to their hard and brittle nature, making it difficult to handle as a substrate for future general lighting and display applications. There has been a demand for the development of a white printed wiring board having heat resistance that does not change color, does not decrease reflectance, and can cope with a large area under high-temperature heat load and UV irradiation.
Further, white LEDs, which are currently mainstream, are composed of blue LEDs (wavelength 470 nm), yellow phosphors, and the like, and are required to have a high reflectance at a wavelength of 470 nm.

  In order to solve these problems, Patent Document 1 discloses that 100 parts by weight of a thermoplastic resin, 0.001 to 10 parts by weight of a specific silicon compound, and 0.05 to 1.0 μm in average particle diameter are used. A thermoplastic resin composition comprising 0.05 to 25 parts by weight of rutile titanium oxide whose surface is treated with at least one compound selected from acid hydrates is described, and the thermoplastic resin composition (Specifically, a 100 × 100 × 2 mm square plate obtained by injection-molding the thermoplastic resin composition) has a high reflectivity of about 90%, dispersibility, surface appearance, and mechanical properties. There is a description that it is excellent in strength and can be suitably used in a wide range of industrial fields.

  Patent Document 2 discloses a white material having an average particle diameter of 0.05 μm to 5 μm as a reflector used in lighting, a display device or the like that does not require a troublesome process and has a high reflectance. A reflector having a surface roughness of 0.5 to 50 μm comprising a pigment and a resin composition containing an inorganic filler having an average particle diameter of 0.5 μm to 10 mm is described, for example, polyaryl ketone, titanium oxide, In addition, a 3 cm square 1 mm square plate is disclosed in which a resin composition containing glass fiber is injection molded.

  Patent Document 3 discloses that 5 to 100 parts by mass of titanium oxide, 0.5 to 30 parts by mass of magnesium hydroxide, and fibrous fillers and needle-like fillers with respect to 100 parts by mass of a specific polyamide resin. The polyamide resin composition for molding an LED reflector containing 20 to 100 parts by mass of the reinforcing agent is described. Specifically, the polyamide resin composition is injection-molded with a thickness of 1 mm, a width of 40 mm, and a length of 100 mm. A plate is disclosed. The reflector made of the resin composition maintains high whiteness without decreasing the reflectance at a wavelength of 470 nm even under a heat load (2 hours at 170 ° C.).

  Further, Patent Document 4 discloses a prepreg and a copper-clad laminate comprising a resin composition containing a cyanate ester compound, a novolac-type epoxy resin and titanium dioxide, and a base material.

Japanese Patent No. 3470730 JP 2007-218980 A JP 2006-257314 A JP 2007-131842 A

  Although the above Patent Documents 1 to 3 disclose a molded article in which a titanium oxide or the like is added to a thermoplastic resin composition to increase the reflectance, all of the disclosed forms are injection molded. A white film that is only a molded product that has been processed into a film and has improved heat resistance or the like has not been studied. Moreover, although the copper clad laminated board of patent document 4 is suppressing the fall of the reflectance under a heat load (180 degreeC 1 hour) compared with the conventional board | substrate (it falls from 80% to 64%), It cannot be said that the heat resistance in a high temperature environment for a long time is sufficient.

  Therefore, the problem of the present invention is that it has heat resistance, has a high reflectance in the visible light region (especially at a wavelength of 470 nm), and has a small decrease in reflectance under a high-temperature heat load environment, and can cope with a large area. It is providing the white film which can be used for the printed wiring board for LED mounting, the metal laminated body which uses this white film, and the board | substrate for LED mounting.

  The present inventors have previously found a white film, a metal laminate, and the like that have high heat resistance, high reflectance in the visible light region, and little reduction in reflectance under a high-temperature heat load environment (Japanese Patent Application No. 2007- 309035). Further, a white film, a metal laminate and the like with little reduction in reflectance under UV irradiation have been found (Japanese Patent Application No. 2008-151547). Although these white films can be suitably used as a printed wiring board for LED mounting having Pb-free heat resistance due to their characteristics, both are from the viewpoint of reflectivity (particularly reflectivity at a wavelength of 470 nm). Was not always satisfactory.

  Therefore, as a result of intensive studies to further improve the problem of reflectance, a composition containing 25 to 100 parts by mass of an inorganic filler with respect to 100 parts by mass of a resin composition containing an amorphous polyetherimide resin. By using an object, it is possible to obtain a white film having high reflectance (especially reflectance at a wavelength of 470 nm) and having little decrease in reflectance even under a high-temperature heat load environment, and this white film can be used for LED mounting printing. It has been found that it can be suitably used as a wiring board, and the present invention has been completed.

  That is, 1st this invention consists of a composition containing 25-100 mass parts of inorganic fillers with respect to 100 mass parts of resin compositions containing an amorphous polyetherimide resin, and has a wavelength of 400-800 nm. The white film is characterized in that the average reflectance is 70% or more and the reflectance reduction rate at a wavelength of 470 nm after heat treatment at 200 ° C. for 4 hours is 10% or less.

In 1st this invention, it is preferable that amorphous polyetherimide resin is resin which has a repeating unit of following Structural formula (1) and / or (2).

  In the first aspect of the present invention, the inorganic filler preferably contains at least a filler having an average particle size of 15 μm or less and an average aspect ratio of 30 or more, and the inorganic filler preferably contains at least titanium oxide. .

In 1st this invention, it is preferable that the average value of the linear expansion coefficient of MD and TD is 35x10 < ^-6 > / degrees C or less, and it is preferable that the thickness of a film is 3-500 micrometers.

  2nd this invention is a metal laminated body formed by laminating | stacking a metal layer on the at least single side | surface of the white film of 1st this invention.

  3rd this invention is a board | substrate for LED mounting formed using the metal laminated body of 2nd this invention.

  According to the present invention, a white film having a high reflectivity in the visible light region (particularly a wavelength of 470 nm), excellent dimensional stability, and little reduction in reflectivity under a high-temperature heat load environment, and a metal using the white film A laminated body can be provided, and these can be suitably used for a printed wiring board for LED mounting because of its characteristics.

FIG. 1 is a view showing an embodiment of an LED mounting substrate and a manufacturing method thereof according to the present invention. FIG. 2 is a view showing an embodiment of an LED mounting substrate and a manufacturing method thereof according to the present invention. FIG. 3 is a view showing an embodiment of the LED mounting substrate and the manufacturing method thereof according to the present invention.

  Hereinafter, although embodiment of this invention is described, the scope of the present invention is not limited to this embodiment.

<White film>
The white film according to the first aspect of the present invention comprises a composition containing 25 to 100 parts by mass of an inorganic filler with respect to 100 parts by mass of a resin composition containing an amorphous polyetherimide resin, and has a wavelength. If the average reflectivity at 400 to 800 nm is 70% or more and the rate of decrease in reflectivity at a wavelength of 470 nm after heat treatment at 200 ° C. for 4 hours is 10% or less, it is not particularly limited and is amorphous. By using the polyetherimide resin, it is possible to obtain an excellent effect that the reflectivity is particularly high at a wavelength of 470 nm and the decrease in reflectivity under a high-temperature heat load environment is extremely small.

  As above-mentioned, although the white film which is 1st this invention requires that the average reflectance in wavelength 400-800nm is 70% or more, this is mounted, so that the reflectance of visible region is high. This is because the brightness of the LED tends to be high, and if it is in the above range, it can be suitably used as a substrate for mounting a white LED. Moreover, since there exists a tendency for a brightness | luminance to become high so that the reflectance of 470 nm vicinity corresponding to the average wavelength (470 nm) of blue LED is high, it is more preferable that the reflectance in 470 nm is 70% or more, and a reflectance is 75%. More preferably.

(Resin composition)
The resin composition constituting the white film according to the first aspect of the present invention contains an amorphous polyetherimide resin. Among them, the repeating unit of the following structural formula (1) and / or (2) is included. Amorphous polyetherimide resin is preferable, and as commercial products of the following structural formula (1), trade names “Ultem CRS5001” (Tg: 226 ° C.), “Ultem UF5011S” (Tg 226 ° C.) manufactured by General Electric Co., Ltd. Etc.

Moreover, as a commercial item of following Structural formula (2), the brand name "Ultem 1000" (Tg: 216 degreeC) by General Electric company, "Ultem 1010" (Tg: 216 degreeC), etc. are mentioned.

  Among the above structural formulas, it is preferable to use amorphous polyetherimide represented by the above structural formula (1) from the viewpoint of reflection characteristics.

(Inorganic filler)
Examples of the inorganic filler contained in the white film of the first invention include talc, mica, mica, glass flake, boron nitride (BN), calcium carbonate, aluminum hydroxide, silica, and titanate (titanium). Potassium oxide, etc.), barium sulfate, alumina, kaolin, clay, titanium oxide, zinc oxide, zinc sulfide, lead titanate, zircon oxide, antimony oxide, magnesium oxide and the like. These may be added singly or in combination of two or more.

  Inorganic fillers are those whose surface is treated with silicone compounds, polyhydric alcohol compounds, amine compounds, fatty acids, fatty acid esters, etc. in order to improve dispersibility in thermoplastic resins. Can be used. Among them, those treated with a silicon compound (silane coupling agent) can be preferably used.

The white film according to the first aspect of the present invention preferably has an average value of linear expansion coefficients of MD (film flow direction) and TD (direction orthogonal to the flow direction) of 35 × 10 ⁻⁶ / ° C. or less. By setting the linear expansion coefficient within such a range, it is possible to achieve an excellent effect that the dimensional stability is excellent, the reflectance is high, and the reflectance is hardly reduced under a high-temperature heat load environment. .

  As a specific method for setting the values of the reflectance and the linear expansion coefficient within the above ranges, the average particle size is 15 μm or less and the average aspect ratio (average particle size / average thickness) is 30 or more with respect to 100 parts by mass of the resin composition. An inorganic filler containing at least a filler 2 having a large refractive index difference between the filler 1 and an amorphous polyetherimide resin serving as a base resin (the refractive index of the filler 2 is approximately 1.6 or more). The method of using 25-100 mass parts can be mentioned. When the amount of the inorganic filler is less than 25 parts by mass, it is difficult to balance the reflectance and the linear expansion coefficient, and when it exceeds 100 parts by mass, the inorganic filler is poorly dispersible or breaks when the film is formed. This may cause problems in moldability, and is not preferable. Thus, by including various fillers (filler 1 and filler 2) having the physical property values specified above as inorganic fillers, good reflectivity and dimensional stability without anisotropy are achieved. An excellent white film can be obtained.

  Examples of the filler 1 having an average particle size of 15 μm or less and an average aspect ratio (average particle size / average thickness) of 30 or more are, for example, synthetic mica, natural mica (mascobite, phlogopite, sericite, szolite, etc.), fired. In addition, inorganic scale-like (plate-like) fillers such as natural or synthetic mica, boehmite, talc, illite, kaolinite, montmorillonite, vermiculite, smectite, and plate-like alumina, and scale-like titanates can be mentioned. According to these fillers 1, the linear expansion coefficient ratio in the plane direction and the thickness direction can be kept low. In consideration of light reflectivity, scaly titanate is more preferable because of its high refractive index. In addition, the said filler can be used individually or in combination of 2 or more types. By using a scaly filler with a high aspect ratio, moisture permeation (moisture absorption) to the film can be suppressed, oxidation deterioration of the thermoplastic resin in a high heat environment can be prevented, and reduction in reflectance can be suppressed. In addition, the rigidity of the film is improved and the film can be used for a thinner substrate.

  The content of the filler 1 is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and further preferably 30 parts by mass or more with respect to 100 parts by mass of the resin composition. . If it is the said range, it is possible to reduce the linear expansion coefficient of the white film obtained to a desired range.

  The filler 2 is an inorganic filler having a large refractive index difference from the base resin. That is, an inorganic filler having a large refractive index and a reference inorganic filler of 1.6 or more are preferable. Specifically, calcium carbonate, barium sulfate, zinc oxide, titanium oxide, titanate, or the like having a refractive index of 1.6 or more is preferably used, and titanium oxide is particularly preferably used.

  Titanium oxide has a significantly higher refractive index than other inorganic fillers, and can increase the difference in refractive index from the base resin. Therefore, the amount of titanium oxide is smaller than when other fillers are used. Excellent reflectivity can be obtained. Even if the film is thinned, a white film having high reflectivity can be obtained.

  The titanium oxide is preferably a crystalline titanium oxide such as anatase type or rutile type. Among them, a rutile type titanium oxide is preferable from the viewpoint of a large difference in refractive index from the base resin.

  Moreover, although the manufacturing method of a titanium oxide has a chlorine method and a sulfuric acid method, it is preferable to use the titanium oxide manufactured by the chlorine method from the point of whiteness.

  The titanium oxide is preferably one whose surface is coated with an inert inorganic oxide. By coating the surface of titanium oxide with an inert inorganic oxide, the photocatalytic activity of titanium oxide can be suppressed, and deterioration of the film can be prevented. As the inert inorganic oxide, it is preferable to use at least one selected from the group consisting of silica, alumina, and zirconia. When these inert inorganic oxides are used, a decrease in the molecular weight of the thermoplastic resin and yellowing can be suppressed during high temperature melting without impairing high reflectivity.

  In addition, in order to enhance dispersibility in the base resin, titanium oxide has a surface made of at least one inorganic compound selected from the group consisting of siloxane compounds, silane coupling agents, etc., a group consisting of polyol, polyethylene glycol, and the like. Those which are surfaced with at least one organic compound selected from In particular, those treated with a silane coupling agent are preferable from the viewpoint of heat resistance.

  The particle size of titanium oxide is preferably 0.1 to 1.0 μm, more preferably 0.2 to 0.5 μm. When the particle size of titanium oxide is in the above range, the dispersibility in the thermoplastic resin is good, the interface with it is densely formed, and high reflectivity can be imparted.

  The content of titanium oxide is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, and most preferably 25 parts by mass or more with respect to 100 parts by mass of the resin composition. Within the above range, good reflection characteristics can be obtained, and good reflection characteristics can be obtained even when the film is thin.

  As a combination of the filler 1 and the filler 2, it is preferable that the titanium oxide and the scale-like inorganic filler are appropriately blended in order to balance the reflectance and the linear expansion coefficient.

(Reduction rate of reflectivity)
The white film of the present invention requires that the reflectance decrease rate at a wavelength of 470 nm after heat treatment at 200 ° C. for 4 hours is 10% or less.

  The grounds for the above conditions are described below. When manufacturing an LED mounting substrate, a high thermal load is applied, such as a thermosetting process (100 to 200 ° C., several hours) of a sealing agent such as a conductive adhesive, epoxy, or silicone resin, or a wire bonding process. Further, even in an actual use environment, development of high-brightness LEDs has progressed, the thermal load on the substrate tends to increase, and the LED element ambient temperature may exceed 100 ° C. in some cases. In the future, it will be important to maintain a high reflectance without discoloration even under such a high heat load environment. The wavelength 470 nm is the average wavelength of the blue LED.

  Therefore, if the rate of decrease in reflectance at a wavelength of 470 nm under the above conditions (200 ° C., 4 hours later) is 10% or less, it is possible to suppress the decrease in reflectance in the manufacturing process, Since it is possible to suppress a decrease in reflectance during actual use, it can be suitably used as an LED mounting substrate. More preferably, it is 5% or less, More preferably, it is 3% or less, Especially preferably, it is 2% or less.

(White film thickness)
The thickness of the white film of the first invention is preferably 3 to 500 μm. More preferably, it is 10-300 micrometers, Furthermore, it is 20-100 micrometers. Within such a range, it can be suitably used as a chip LED used as a surface light source for a cellular phone backlight or a liquid crystal display backlight that is required to be thin.

(Additives, etc.)
In the composition constituting the white film of the first invention, various additives other than other resins and inorganic fillers, such as heat stabilizers, ultraviolet absorbers, and light stabilizers, are added to such an extent that the properties are not impaired. Further, a nucleating agent, a coloring agent, a lubricant, a flame retardant and the like may be appropriately blended. Moreover, it does not restrict | limit especially as a preparation method of the resin composition of this invention, A well-known method can be used. For example, (a) A resin is prepared by separately preparing a master batch in which various additives are mixed in an amorphous polyetherimide resin at a high concentration (typically 10 to 60% by weight). (B) A method of mechanically blending various additives directly into the resin to be used using a kneader or an extruder. Etc. Among the above mixing methods, the method of preparing and mixing the master batch (a) is preferable from the viewpoint of dispersibility and workability. Furthermore, the surface of the film may be appropriately subjected to embossing, corona treatment or the like for improving handling properties.

(Method for forming white film)
As a method for forming the white film of the first present invention, a known method such as an extrusion casting method using a T-die or a calendar method can be employed, and although not particularly limited, From the viewpoint of film properties and stable productivity, an extrusion casting method using a T die is preferable. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film forming properties of the composition, but is generally about the melting point or higher and 430 ° C. or lower. In addition, when a crystalline resin is used, a crystallization treatment method for imparting heat resistance is not particularly limited. For example, a method of crystallization at the time of extrusion casting (cast crystallization method) or film formation In-line crystallization methods using heat treatment rolls or hot-air ovens (in-line crystallization method) and out-of-film crystallization methods in hot-air ovens or hot presses (outline crystallization methods). it can.

<Metal laminate>
The metal laminate according to the second invention is not particularly limited as long as a metal layer is laminated on at least one surface of the white film. Examples of the metal layer include copper, gold, silver, aluminum, nickel. A metal foil having a thickness of about 5 to 70 μm, such as tin, can be used. Among these, as the metal foil, a copper foil is usually used, and a metal foil having a surface subjected to chemical conversion treatment such as black oxidation treatment is preferably used. In order to enhance the adhesive effect, it is preferable to use a conductor foil that has been chemically or mechanically roughened on the contact surface (surface to be overlapped) side in advance. Specific examples of the conductor foil that has been subjected to surface roughening treatment include a roughened copper foil that has been electrochemically treated when an electrolytic copper foil is produced.

  As for the method for laminating the metal foil, a known method can be adopted as a heat fusion method without interposing an adhesive layer as long as it is a method by heating and pressurization, and is not particularly limited. For example, a hot pressing method, a hot laminating roll method, an extrusion laminating method in which the extruded resin is laminated with a cast roll, or a method combining these can be suitably employed.

<LED mounting board>
The substrate for mounting LED according to the present invention is not particularly limited as long as it uses the metal laminate, and examples thereof include a double-sided substrate and a composite substrate with an aluminum plate. The conventional white substrate made of thermosetting resin contains glass cloth, so problems such as voids (bubbles) tend to remain in the manufacturing process, thinning is difficult, and even in ceramic substrates, Although it is difficult to reduce the thickness due to its hard and brittle nature, it is possible to reduce the thickness by using the white film of the present invention and a metal laminate comprising the same. Can be preferably used. In addition, by including various fillers (filler 1 and filler 2) having specific physical properties as fillers, it is possible to provide a double-sided substrate with a balance of reflection characteristics, dimensional stability, and rigidity. Is possible.

  In addition, in the case where more heat dissipation is required with the increase in luminance of the LED, it is possible to improve the heat dissipation by combining with an aluminum plate. As a structure of the composite substrate with the aluminum plate, when the metal laminate made of the white film of the present invention is laminated on the entire surface of the aluminum plate, or for the cavity (concave) structure on the metal laminate made of the white film of the present invention. The case where a window frame is extracted and laminated | stacked is mentioned. The aluminum to be used is preferably roughened in consideration of adhesion to the thermoplastic resin, but when considering the cavity structure, mirror surface aluminum is used to efficiently reflect the light from the LED. It is preferable to use it. In terms of improving heat dissipation, it is preferable that the thickness of the film is thin.

  The method for producing the LED mounting substrate of the present invention is not particularly limited, and in the case of a double-sided substrate, for example, it can be produced according to the method shown in FIG. As shown in FIG. 1, (a) First, a white film (100) and two copper foils (10) to be a metal layer are prepared, and (b) a copper foil (100) on both sides of the white film (100). 10) is laminated by a vacuum press to produce a metal laminate, and (c) a copper foil (10) is etched or plated on copper to form a wiring pattern (20) to form an LED mounting substrate. (D) The LED (200) is mounted on this substrate, and is used by being connected to the conductor pattern (20) by the bonding wire (30) (LED mounting substrate).

  Moreover, in the case of a composite substrate with an aluminum plate (metal radiating part), it can be manufactured, for example, according to the method shown in FIGS. As shown in FIG. 2, (a) a copper foil (10) is laminated on one side of a white film (100) to produce a metal laminate, and (b) the copper foil (10) is etched to form a wiring pattern (20 And (c) an aluminum plate (300) is laminated on the surface opposite to the surface on which the wiring pattern (20) is formed by vacuum pressing to form an LED mounting substrate. (D) The LED (200) is mounted on this substrate, and is used by being connected to the conductor pattern (20) by the bonding wire (30) (LED mounting substrate). In addition, about the lamination | stacking method with the said aluminum plate, it is not restrict | limited to a vacuum press method, For example, the method similar to the lamination | stacking method with the metal foil mentioned above can be mentioned.

Furthermore, as shown in FIG. 3, (a) a copper laminate (10) is laminated on one side of the white film (100) to produce a metal laminate, and (b) the copper foil (10) is etched to form a wiring pattern. (20) is formed, and the white film (100) is punched into the cavity frame using a big die (40). (C) The aluminum plate (300) is formed on the surface opposite to the surface on which the wiring pattern (20) is formed. ) Are laminated by a vacuum press to obtain an LED mounting substrate. (D) The LED (200) is mounted on this substrate, and is used by being connected to the conductor pattern (20) by the bonding wire (30) (LED mounting substrate). Note that the method of punching into the cavity frame is not limited to the method using the Bic die, and for example, it can be formed using a laser.
[Example]

  Hereinafter, although an Example and a comparative example demonstrate in more detail, this invention is not limited to these.

  In addition, the various measured values and evaluation about the film etc. which are shown in this specification were calculated | required as follows.

[Average reflectance]
An integrating sphere is attached to a spectrophotometer ("U-4000", manufactured by Hitachi, Ltd.), and the reflectance when the reflectance of the alumina white plate is 100% is measured at intervals of 0.5 nm over a wavelength range of 400 nm to 800 nm. did. The average value of the measured values obtained was calculated, and this value was taken as the average reflectance. Table 1 also shows the reflectance at wavelengths of 460 nm, 470 nm, and 480 nm.

[Reflectance after heat treatment]
The obtained white film was heat-treated in a hot air circulation oven at 200 ° C. for 4 hours, and the reflectance after the heat treatment was measured in the same manner as described above, and the reflectance at 460 nm, 470 nm, and 480 nm was read. The results are shown in Table 1.

[Measurement of linear expansion coefficient]
Using a thermal stress strain measuring device TMA / SS6100 manufactured by Seiko Instruments Inc., a strip-shaped test piece (length: 10 mm) cut out from the film is fixed with a tensile load of 0.1 g, and from 30 ° C. to 5 ° C./min. The temperature was increased to 220 ° C. at a rate of 30 ° C. to 140 ° C. of the thermal expansion amounts of MD (α1 (MD)) and TD (α1 (TD)).

[Average particle size]
Using a powder specific surface measuring instrument (transmission method) of model “SS-100” manufactured by Shimadzu Corporation, a sample tube having a cross-sectional area of 2 cm ² and a height of 1 cm was filled with 3 g of sample, and 20 cc with a 500 mm water column. The air permeation time was measured, and the average particle size of titanium oxide was calculated from this.

  30 parts of titanium oxide (average particle size 0.23 μm, alumina treatment, silane coupling agent treatment) produced by the chlorine method is applied to 100 parts by mass of a resin composition made of an amorphous polyetherimide resin (Ultem UF5011S). A composition obtained by mixing 21 parts by mass of synthetic mica having a mass part, an average particle diameter of 5 μm, and an average aspect ratio of 50 was melt-kneaded, and the thickness was set at 380 ° C. using an extruder equipped with a T die. A 100 μm film was prepared. The evaluation results are shown in Table 1.

  A film having a thickness of 100 μm was produced in the same manner as in Example 1 except that titanium oxide was changed to 67 parts by mass in Example 1. The evaluation results are shown in Table 1.

  A composition similar to that of Example 1 was melt-kneaded and extruded, and at the same time, a copper foil (12 μm) was laminated from one side to prepare a single-sided copper foil film having a single-sided copper foil of 12 μm and a resin thickness of 100 μm. The evaluation results are shown in Table 1. The measurement was performed in the same manner as in Example 1 after etching the entire surface of the single-sided copper foil. The reflectance was measured on the etched surface.

  A film having a thickness of 100 μm was prepared in the same manner as in Example 1. Thereafter, 12 μm of copper foil was laminated on both sides of the film under a condition of 250 ° C. peak temperature, holding time 30 minutes, 5 MPa in a vacuum press, and the resin thickness A double-sided copper foil film having a thickness of 100 μm was prepared. The evaluation results are shown in Table 1. The measurement was performed in the same manner as in Example 1 after etching the entire surface of the double-sided copper foil.

  After etching the metal laminate (single-sided copper-clad film) produced in Example 3, it is punched into a cavity frame to form a cavity hole, and laminated with mirror surface aluminum at 250 ° C. and 5 MPa for 30 minutes by vacuum press, An LED mounting substrate was manufactured.

  A film having a thickness of 100 μm was produced in the same manner as in Example 1 except that the amorphous polyetherimide resin (Ultem 1000) was changed in Example 1. The evaluation results are shown in Table 1.

A film having a thickness of 100 μm was produced in the same manner as in Example 1 except that the amorphous polyetherimide resin (Ultem 1000) was changed in Example 2. The evaluation results are shown in Table 1.
[Comparative Example 1]

The copper foil on both sides of a double-sided copper-clad laminate (CCL-HL820WDB, resin thickness 100 μm) manufactured by Mitsubishi Gas Chemical Co., Ltd. was etched on the entire surface, and then measured in the same manner as in Example 1. The evaluation results are shown in Table 1.
[Comparative Example 2]

The copper foil on both sides of a double-sided copper-clad laminate (CS-3965, resin thickness 100 μm) manufactured by Risho Kogyo Co., Ltd. was etched on the entire surface, and then measured in the same manner as in Example 1. The evaluation results are shown in Table 1.

From the result of Table 1, in Examples 1-7, it was confirmed that it is excellent in the reflectance and the reflectance after heat processing. Furthermore, in Examples 1, 3 and 4, it was confirmed that the linear expansion coefficient was low and the dimensional stability was excellent.
In addition, when the resin represented by the structural formula (1) is used as the amorphous polyetherimide resin, it is more reflective than when the resin represented by the structural formula (2) is used. The rate was confirmed to be excellent. In particular, as can be seen from the comparison between Examples 1 and 2 and Examples 6 and 7, when the resin represented by the structural formula (1) is used, the average wavelength of blue LEDs is around 470 nm. It was confirmed that the reflectance was high.
On the other hand, in Comparative Examples 1 and 2, although the initial reflectance was high, it was confirmed that the decrease in reflectance after the heat treatment was large.

10 Copper foil 20 Conductor pattern 30 Bonding wire 100 White film 200 LED
300 Aluminum plate

Claims (8)

It consists of a composition containing 25 to 100 parts by mass of an inorganic filler with respect to 100 parts by mass of a resin composition containing an amorphous polyetherimide resin,
A white film having an average reflectance at a wavelength of 400 to 800 nm of 70% or more and a reduction rate of the reflectance at a wavelength of 470 nm after heat treatment at 200 ° C. for 4 hours is 10% or less. The white film of Claim 1 whose amorphous polyetherimide resin is resin which has a repeating unit of following Structural formula (1) and / or (2).

  The white film according to claim 1 or 2, wherein the inorganic filler contains at least a filler having an average particle size of 15 µm or less and an average aspect ratio of 30 or more.   The white film according to claim 1, wherein the inorganic filler contains at least titanium oxide. The white film in any one of Claims 1-5 whose average value of the linear expansion coefficient of MD and TD is 35 * 10 < ^-6 > / degrees C or less.   The white film in any one of Claims 1-4 whose thickness of a film is 3-500 micrometers.   The metal laminated body formed by laminating | stacking a metal layer on the at least single side | surface of the white film in any one of Claims 1-6.   The board | substrate for LED mounting formed using the metal laminated body of Claim 7.

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