DESCRIPTION
TITLE OF THE INVENTION:
LIGHT-TRANSMITTING RESIN COATING COMPOSITION, AND LIGHT
REFLECTING MEMBER AND LIGHTING APPARATUS USING THE SAME
TECHNICAL FIELD
[0001]
The present invention relates to a light-transmitting resin coating composition
suitable for use in a light reflecting member having a silver reflective surface, and a light
reflecting member and a lighting apparatus using the same.
BACKGROUND ART
[0002]
Conventionally, silver having excellent light reflection characteristics is used as a
mirror surface material on the reflective surface of a light reflecting member that reflects
light from the light source of a lighting apparatus. Especially, when silver is used in a
bowl-shaped light reflecting member such as a downlight or a spotlight, the light use
efficiency of the lighting apparatus can be enhanced because light is reflected without loss
within the light reflecting member. However, silver tends to react with oxygen, water,
sulfurous acid gas, or the like in the air to form silver oxide or silver sulfide, which causes
discoloration or corrosion. Discoloration or corrosion on the surface of silver used at a
reflective surface not only impairs the appearance of the light reflecting member but also
decreases the light use efficiency of the lighting apparatus due to a decrease in reflectance.
[0003]
For the purpose of inhibiting discoloration or corrosion of silver, a coating
composition to cover and protect a silver material is known (see, for example, Japanese
Laid-open Patent Publication No. HEI 6-57198). In addition, there is also known a
reflective coating comprising an undercoat layer formed by applying a modified silicone
resin coating to a substrate made of FRP, a deposited silver film provided on the undercoat
layer, and a topcoat layer formed by applying a modified silicone resin coating onto the
deposited silver film (see, for example, Japanese Laid-open Patent Publication No.
2000-106017). Further, there is known a light reflecting member comprising a silver layer
formed on the surface of a substrate and a cured coating layer that is formed on the silver
layer and consists of at least one kind of resin selected from silicone acrylic resin, silicone
alkyd resin, and specific multifunctional cross-linked silicone resin having siloxane bonds
in the main chain (see, for example, WO 99/62646).
[0004]
However, the coating composition disclosed in Japanese Laid-open Patent
Publication No. HEI 6-57198 consists mainly of a silicone acrylic resin, which is cured at
room temperature, and therefore it is not suitable for use under high temperature
conditions. For example, if a light reflecting member using this coating composition is
continuously exposed to high power light including ultraviolet light from a mercury lamp
or the like in a high temperature environment of about 160°C, a crack may be formed in
the coating, whereby the appearance may be impaired. If the above light reflecting
member is used in such an environment continuously over a long period of time, e.g. 10,000
hours, the coating may be broken, which may prevent protection of the light reflecting
layer containing silver and, as a result, degrade the reflection characteristics of the silver.
[0005]
Further, if the light reflecting member disclosed in Japanese Laid-open Patent
Publication No. 2000-106017 is exposed to the above described mercury lamp for a long
period of time, the light reflecting member reaches a high temperature of about 160° C by
heat from the light source. Besides, since the light reflecting member is continuously
irradiated with ultraviolet light, the topcoat layer is discolored to yellow or brown and thus
the appearance is impaired. If the member continues to be in this state, the silver film is
discolored due to degradation products in the undercoat layer, which further impairs the
appearance and lowers the reflectance.
[0006]
Further, the light reflecting member disclosed in WO 99/62646 uses a highly gas
permeable silicone material. Therefore, if the member is used over a long period of time
in an environment where hydrogen sulfide or other gas is concentrated as compared to the
general environment, discoloration of the silver may occur to lower the reflectance. Thus,
this light reflecting member is not suitable for use in a lighting apparatus to be used in a
place where exhaust gas containing hydrogen sulfide or the like is concentrated, e.g. a
chemical facility or a tunnel.
DISCLOSURE OF THE INVENTION
[0007]
The present invention has been made in view of the above described problems.
An object of the present invention is to provide a light-transmitting resin coating
composition that is highly resistant to ultraviolet rays and highly cross-linked and has
high gas barrier properties so as to be able to maintain high reflectivity under high
temperature conditions over a long period of time when it is used to cover a silver reflective
layer of a light reflecting member, and to provide a light reflecting member and a lighting
apparatus using the same.
[0008]
In order to solve the above described problems, a light-transmitting resin coating
composition according to the present invention comprises the following components: (A) an
acrylic resin having hydroxyl groups as cross-linking sites; (B) 20 to 80 parts by mass of a
melamine resin per 100 parts by mass of solid content of the above acrylic resin (A); and
(C) 0.1 to 10 parts by mass of an epoxy-containing silane compound or acrylic resin per 100
parts by mass of the solid content of the above acrylic resin (A).
[0009]
Preferably, the above light-transmitting resin coating composition further
comprises- (D) a total of 0.1 to 20 parts by mass of a triazole ultraviolet absorber and/or a
triazine ultraviolet absorber per 100 parts by mass of the solid content of the above acrylic
resin (A).
[0010]
Preferably, the above light-transmitting resin coating composition further
comprises: (E) 0.1 to 10 parts by mass of an organic sulfonic acid per 100 parts by mass of
the solid content of the above acrylic resin (A).
[0011]
Preferably, in the above hght-transmitting resin coating composition, the
melamine resin (B) comprises a methylated melamine resin.
[0012]
Preferably, the above hght-transmitting resin coating composition further
comprises: (F) 1 to 100 parts by mass of a fluorine resin, which has fluoroalkylene groups
or perfluoroalkyl groups in a skeleton and has hydroxyl groups as cross-linking sites, per
100 parts by mass of the solid content of the above acrylic resin (A).
[0013]
Preferably, the above hght-transmitting resin coating composition further
comprises: (G) 0.1 to 10 parts by mass of at least either a hindered amine light stabilizer or
a benzoate light stabilizer per 100 parts by mass of the solid content of the above acrylic
resin (A).
[0014]
According to the present invention, a light reflecting member having a reflective
surface protected by a Hght-transmitting resin coating composition as described above is
also provided. Preferably, such a light reflecting member comprises a substrate, a light
reflecting layer formed of Ag or Ag base alloy on the substrate, and a topcoat layer formed
on the light reflecting layer, wherein the above topcoat layer comprises a hght-transmitting
resin coating composition as described above.
[0015]
A light reflecting member as described above may comprise a substrate, an
undercoat layer formed on a surface of the substrate, a light reflecting layer formed of Ag
or Ag base alloy on the undercoat layer, and a topcoat layer formed on the light reflecting
layer, wherein the above topcoat layer comprises any one of the light-transmitting resin
coating compositions described above.
[0016]
In such a case, it is preferable that the above topcoat layer comprises silica
particles or acrylic particles.
[0017]
Further, according to the present invention, a lighting apparatus that comprises a
light reflecting member as described above so as to reflect light from a light source by the
light reflecting member is also provided.
[0018]
According to the light-transmitting resin coating composition of the present
invention, since the above components (A), (B), and (C) are contained, a coating that is
highly resistant to ultraviolet rays and highly cross-linked as well as having high gas
barrier properties can be formed. Thus, the above light reflecting member with the
topcoat layer formed by using the light -transmitting resin coating composition can
maintain high reflectivity under high temperature conditions over a long period of time.
Further, the above lighting apparatus using the light reflecting member can provide high
light use efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
FIG. 1 is a partially exploded sectional view of a lighting apparatus using a light
reflecting member according to one embodiment of the present invention.
FIG. 2 is a sectional side view of the same light reflecting member.
FIG. 3 is a sectional side view of a light reflecting member according to a modified
example of the above embodiment.
FIG. 4 is a sectional side view of a light reflecting member according to another
modified example of the above embodiment.
MODES FOR CARRYING OUT THE INVENTION
[0020]
Referring to FIG. 1 and FIG. 2, one embodiment of the present invention is
described. FIG. 1 and FIG. 2 show an example of a lighting apparatus using a light
reflecting member 1 of this embodiment according to this embodiment (hereinafter referred
to as lighting apparatus 2). This lighting apparatus 2 may be used in general facilities,
stores, houses, and so on. As can be seen from FIG. 1, a downlight is shown here as a
configuration example of the lighting apparatus 2. This lighting apparatus 2 comprises a
light source 3 and the light reflecting member 1 to reflect light from the light source 3.
The light reflecting member 1 is shaped like a bowl to become wider from the socket
portion, on which a socket 4 for mounting of the light source 3 is provided, to the central
portion and the opening portion in the direction of light emission. The socket portion is
connected to a main body 5 of the lighting apparatus 2, and a flat spring 6 to secure the
lighting apparatus 2 to the ceiling is attached to the opening portion. The main body 5 is
provided with a ballast 7 appropriate to the light source 3, and the like.
[0021]
As shown in FIG. 2, the light reflecting member 1 comprises a substrate 11, an
undercoat layer 12 formed on the substrate 11, a light reflecting layer 13 as a reflective
surface formed of silver (Ag) or an Ag base alloy, and a topcoat layer 14 formed on the light
reflecting layer 13 so as to serve as coating to cover the reflective surface.
[0022]
The substrate 11 is made of a material resistant to heat generated by the light
source 3. Materials used for the substrate 11 include, but are not limited to, organic
materials such as resin, inorganic materials such as metals and glass, and combinations of
these materials. Further, the substrate 11 is shaped so that light from the light source 3
can be efficiently reflected to realize desired light distribution depending on specifications
of the lighting apparatus 2 or the like, and it does not necessarily have to be bowl-shaped
as described above.
.[0023]
The material for the substrate 11 may be, for example, a thermoplastic resin such
as polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyphenylene
sulfide (PPS), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), thermoplastic
polyimide (PI), polyetherimide (PEI), polycarbonate (PC), liquid crystal polymer (LCP),
syndiotactic polystyrene (SPS), or the like. In addition, the material may be a
thermosetting resin such as unsaturated polyester (UP), which is generally used as a
material for bulk molding compound (BMC), or the like.
[0024]
In order to enhance heat resistance, strength, light resistance, and so on, various
additives such as inorganic fillers may be added to the resin materials. Alternatively, for
the same purpose, a number of thermoplastic resins may be block copolymerized by using a
polymer blend or a compatibilizing agent. In addition, the substrate 11 is formed into a
given shape by, for example, methods generally used for resin molding such as injection
molding, compression molding, vacuum molding, pressure forming, and so on.
[0025]
Metals to be used as the material for the substrate 11 include aluminum (Al) base
alloys, magnesium (Mg) base alloys, iron (Fe) base alloys, and so on. The substrate 11
may be formed by an appropriate method selected in consideration of the material, the
required shape of the light reflecting member 1, and so on, e.g., spinning, press working,
die casting, or thixomolding. In the case where glass is used as the material for the
substrate 11, the forming methods include press working and blowing. After forming of
the substrate 11, if machining oil, a mold release agent, gas at the time of the forming, or
the like is attached to the surface, it is preferably removed by a physical or chemical
method.
[0026]
The undercoat layer 12 is formed so as to enhance the adhesion between the
substrate 11 and the light reflecting layer 13 and to enhance the smoothness of the
substrate 11. As long as the substrate 11 is made of a resin material and the adhesion to
the light reflecting layer 13 as well as the smoothness is sufficiently ensured, it is not
necessary to form the undercoat layer 12. The undercoat layer 12 is formed by applying a
coating of a resin material, e.g. polyvinyl resin, acrylic resin, silicone resin, fluorine resin,
epoxy resin, or melamine resin. With respect to the coating method, known methods such
as spray coating,spin coating, roll coating, and dip coating may be selectively used. With
respect to the curing method, known means such as heat, ultraviolet radiation, and
electron radiation may be used. The thickness of the undercoat layer 12 is not
particularly limited but, for example, 5 to 30 nm is preferable. If the undercoat layer 12 is
too thick, it may have an unfavorable effect on the substrate 11 designed in consideration
of the direction of light emission.
[0027]
The material for the light reflecting layer 13 is not particularly limited, as long as
it is Ag or an Ag base alloy, but preferably consists mainly of Ag and contains at least 90
at % Ag. The Ag may contain copper (Cu) or other impurities, but the impurity content is
preferably less than 10 at %. Further, by using, as the Ag base alloy, an alloy of Ag and
gold (Au), neodymium (Nd), bismuth (Bi), silicon (Si), Mg, or other material, the durability
of the light reflecting layer 13 containing Ag can be enhanced. Methods for forming the
light reflecting layer 13 include vacuum deposition methods, magnetron sputtering
methods, ion plating methods, ion assisted methods, plasma assisted methods, and
physical vapor deposition methods (PVD).
[0028]
Next, with respect to a light-transmitting resin coating composition that makes up
the topcoat layer 14, each component of the base substance of the coating is described.
The light-transmitting resin coating composition that makes up the topcoat layer 14 of this
embodiment comprises the following components (A) to (C): (A) an acrylic resin having
hydroxyl groups as cross-linking sites; (B) 20 to 80 parts by mass of a melamine resin per
100 parts by mass of the solid content of the above acrylic resin (A); and (C) 0.1 to 10 parts
by mass of an epoxy-containing silane compound or acrylic resin per 100 parts by mass of
the solid content of the above acrylic resin (A).
[0029]
The component (A), an acrylic resin having hydroxyl groups as cross -linking sites,
is a component acting as the skeleton of resin. The component (A) is not particularly
limited, as long as it is an acrylic resin having hydroxyl groups, but "LR2629"
manufactured by Mitsubishi Rayon Co., Ltd., "A814" and "A817" manufactured by DIC
Corporation, and so on, which are commercially available, may be preferably used. In
view of the light resistance, a styrene-free acrylic resin is more preferable, and in view of
the compatibility and the curability, a resin having a molecular weight (Mw) of 10000 to
50000 is especially preferable. An acrylic resin obtained by polymerizing an unsaturated
monomer mixture selected from unsaturated monomers containing hydroxyl groups,
unsaturated monomers containing acid groups, and other unsaturated monomers may be
used as the acrylic resin having hydroxyl groups.
[0030]
The above unsaturated monomers containing hydroxyl groups include, but are not
limited to, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate
hydroxybutyl acrylate, "Placcel FMl" ( e -caprolactone modified hydroxyethyl
methacrylate) manufactured by DAICEL CORPORATION, polyethylene glycol
monoacrylate or monomethacrylate, and polypropylene glycol monoacrylate or
monomethacrylate.
[0031]
The above unsaturated monomers containing acid groups include, but are not
limited to, carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic
acid, and maleic acid.
[0032]
The above other unsaturated monomers include, but are not limited to: a
ester-containing acrylic monomer such as methyl, ethyl, propyl, butyl, hexyl, ethylhexyl, or
lauryl acrylate or methacrylate; a vinyl alcohol monomer of vinyl alcohol and carboxylic
acid such as acetic acid, propionic acid, or the like; an unsaturated hydrocarbon monomer
such as styrene, alpha-methylstyrene, vinylnaphthalene, butadiene, or isoprene,' a nitrile
monomer such as acrylonitrile or methacrylonitrile; and an acrylamide monomer such as
acrylamide, metacrylamide, N-methylolacrylamide, N, N-dimethylacrylamide, or diacetone
acrylamide.
[0033]
The component (B) is a curing agent component, and by using a melamine resin, a
highly cross-linked coating can be achieved. Melamine resin is classified as an amino
resin. Since the light resistance and cross-linking properties of resins other than
melamine resin, e.g., benzoguanamine resin, glycoluril resin, and urea resin are lower than
those of melamine resin, a highly light resistant and heat resistant coating required for
this embodiment cannot be achieved.
[0034]
Preferably, an alkyl etherified melamine resin is used. Other types, e.g., imino
types or methylol types, are not preferable because the storage stability of the coating is
lowered when trifunctional or tetrafunctional alkoxysilane is contained in the resin
composition. This is because, if a partially hydrolyzed condensate of the alkoxysilane
compound is treated with a silane coupling agent, imino type melamine resin or methylol
type melamine resin easily reacts with the condensate. It is especially preferable to use,
as the alkyl etherified melamine resin, a melamine resin substituted by at least one of
methoxy and butoxy. Melamine resins substituted by methoxy or butoxy include
melamine resins etherified with i-butyl or n-butyl alone or with butyl and methyl. These
melamine resins have excellent coating storage stability and are hydrophobic. Therefore,
when such a melamine resin is used for forming a coating, the melamine resin is
eccentrically located in the upper part of the coating so that the crosslink density at the
coating surface is increased. This can inhibit infiltration of contaminants into the coating
so as to enhance the contamination resistance.
[0035]
The content of amino resin in the resin composition is not particularly limited, but
is preferably set at 10 to 50 mass%, more preferably 15 to 40 mass%, to the solid content of
acrylic resin. If the content of amino resin is high, the resulting coating is hard and
brittle. On the other hand, if the content of amino resin is low, the degree of cross-linking
is insufficient and thus the resulting coating is not hard enough and has low chemical
resistance.
[0036]
As described above, the content of the component (B) is preferably 20 to 80 parts
by mass, more preferably 25 to 50 parts by mass, per 100 parts by mass of the acrylic resin
(A). If the content of melamine resin is too high, the resulting coating is too hard and
therefore has low adhesion properties as well as having low light resistance. On the other
hand, if the content of melamine resin is too low, cross-linkages in the resulting coating is
insufficient and thus the gas barrier properties are low.
[0037]
The melamine resin (B) may be a methylated melamine resin. Since a
methylated melamine resin has high reactivity to melamine resin and little
self-condensation, the resulting coating can be dense so as to have high crosslink density
and high gas barrier properties.
[0038]
The component (C) is a component to provide adhesion properties. By using an
epoxy containing silane compound or aery he resin, high adhesion to the base (light
reflecting layer 13) is exhibited. For example, KBM-303, KBM403, KBE-402, KBE-403,
X-41-1053, X-41-1056, and so on manufactured by Shin-Etsu Chemical Co., Ltd. may be
used as the component (C). As the epoxy-containing acrylic resin, Blemmer CP-15, CP-30,
or CP-50M, Marproof G-1005S or G-1010S, manufactured by NOF CORPORATION, or the
like may be used.
[0039]
As described above, the content of the component CO is preferably 0.1 to 10 parts
by mass, more preferably 1 to 6 parts by mass, per 100 parts by mass of the acrylic resin
(A). If the content of epoxy-containing compound is too high, the resulting coating is not
dense and thus has low gas barrier properties. On the other hand, if the content of
epoxy-containing compound is too low, the adhesion to the base is decreased, which
prevents Ag from being protected for a long period of time.
[0040]
The light-transmitting resin coating composition configured as described above
comprises a highly light resistant acrylic resin, a highly cross-linked melamine resin, and a
highly adhesive epoxy compound as components of the base substance of the coating for
silver. By curing the components to form the topcoat layer 14, a colorless and transparent
coating composition with high visible light transmission can be obtained. The cured
coating is superior in heat resistance and light resistance, so that discoloration, cracking,
and so on can be prevented.
[0041]
. Preferably, the light-transmitting resin coating composition of this embodiment
further comprises, as a component (D), a total of 0.1 to 20 parts by mass, more preferably 2
to 10 parts by mass, of a triazole ultraviolet absorber and/or a triazine ultraviolet absorber
per 100 parts by mass of the solid content of the acrylic resin (A).
[0042]
This component (D), which is a component to absorb ultraviolet light, can be added
to enhance the light resistance. Among ultraviolet absorbers, a triazole ultraviolet
absorber or a triazine ultraviolet absorber is preferably used in consideration of solvents,
solubility in resin, and durability. As for a triazole ultraviolet absorber, EVERSORB 70,
71, 72, 73, or 74 manufactured by Everlight Chemical Industrial Corporation, TINUVIN
PS, 99, 109, or 328 manufactured by BASF, or the like may be used. As for a triazine
ultraviolet absorber, SB-UVA 6164 or 6577 manufactured by Everlight Chemical Industrial
Corporation, TINUVIN 400, 405, or 479 manufactured by BASF, or the like may be used.
Either or both of the above ultraviolet absorbers may be used.
[0043]
As described above, the content of the component (D) is preferably 0.1 to 20 parts
by mass per 100 parts by mass of the acrylic resin (A). If the content is too high, the cross
linking is decreased and thus the gas barrier properties are lowered. On the other hand,
if the content is less than 0.1 parts by mass, the effect of ultraviolet absorption is hardly
achieved.
[0044]
Preferably, the light-transmitting resin coating composition of this embodiment
further comprises, as a component (E), 0.1 to 10 parts by mass, more preferably 0.3 to 4
parts by mass, of an organic sulfonic acid per 100 parts by mass of the solid content of the
acrylic resin (A). For facilitating the cross linking of melamine resin, a small amount of
organic sulfonic acid of the component (E) may be added as a catalyst so as to improve the
gas barrier properties. Such sulfonic acids include p-toluenesulfonic acid, benzenesulfonic
acid, decanesulfonic acid, and perfluorosulfonic acid. As described above, the addition
amount is preferably 0.1 to 10 parts by mass relative to the acrylic resin (A). If the
content of organic sulfonic acid is too high, curing shrinkage is increased and thus the
adhesion to the base is decreased although the gas barrier properties are improved. On
the other hand, the content of organic sulfonic acid is too low, the catalytic effect is hardly
achieved.
[0045]
Preferably, the light-transmitting resin,coating composition of this embodiment
further comprises, as a component (F), 1 to 100 parts by mass, more preferably 5 to 30
parts by mass, of a fluorine resin, which has fLuoroalkylene groups or perfluoroalkyl groups
in the skeleton and has hydroxyl groups as cross linking sites, per 100 parts by mass of the
sohd content of the acrylic resin (A). By adding and curing the fluorine resin (F), which is
a resin containing highly light resistant and heat resistant fluorine-containing groups
(fluoroalkylene groups or perfluoroalkyl groups) in the skeleton, the light resistance and
heat resistance of the resin composition can be enhanced.
[0046]
This fluorine containing resin is not particularly limited as long as it is a resin
having cross-linking groups, but is preferably a copolymer of an acrylic monomer in the
acrylic resin described with respect to the component (A) and a fluorine containing
monomer. Specific examples include fluorinated monomers such as trifiuoroethyl
(methjacrylate, perfLuorodecylethyl (meth)acrylate, perfluorooctylethyl (meth)acrylate,
perfluorohexylethyl (meth)acrylate, perfluorobutylethyl (meth)acrylate, or
perfluoropolyether (meth)acrylate. Further, specific examples of vinyl monomers include
trifLuoromethyl vinyl, perfluoroethyl vinyl, and perfluoroethyl ether vinyl. Here,
"(meth)acrylate" means acrylate or methacrylate.
[0047]
A fiuoroolefin, which contains fluorine and has carbon-carbon double bonds, may
be further polymerized. Fluoroolefins include vinylidene fluoride, tetrafluoroethylene,
chlorotriQuoroethylene, and hexafluoropropene. These fluoroolefins may be used
independently or two or more of those may be used in combination.
[0048]
Preferably, the light-transmitting resin coating composition of this embodiment
further comprises, as a component (G), 0.1 to 10 parts by mass, more preferably 1 to 5
parts by mass, of at least either a hindered amine light stabilizer or a benzoate light
stabilizer per 100 parts by mass of the solid content of the acrylic resin (A).
[0049]
This component (G) is a component that consumes radicals generated by
ultraviolet rays for stabilization. By the addition of such a light stabilizer, the light
resistance of the resin composition itself can be significantly enhanced. As for the
hindered amine light stabilizer, EVERSORB 90, 91, 93, or 95 manufactured by Everlight
Chemical Industrial Corporation, TINUVIN 123, 144, or 152 manufactured by BASF, or
the like, which is commercially available, may be used. As for the benzoate light stabilizer,
TINUVIN 120, SB-UVA612 manufactured by Shuang-Bang Industrial Corp., or the like
may be used. Either or both of the light stabilizers may be used.
[0050]
Examples of the commercially available products include LUMIFLON
manufactured by Asahi Glass Co., Ltd., water repellent resin ZX manufactured by Fuji
Kasei Kogyo Co., Ltd., Cefral Coat manufactured by Central Glass Co., Ltd., and Fclear
manufactured by Kanto Denka Kogyo Co., Ltd. As described above, the content of the
component (F) is preferably 1 to 100 parts by mass per 100 parts by mass of the acrylic
resin (A). If the content of fluorine resin is too high, the degree of non-adherence, which is
a characteristic of fluorine resin, is increased and thus the adhesion is decreased.
[0051]
In order to allow the light-transmitting resin coating composition containing the
above components (A) to (G) to be formed as a coating composition, various solvents may be
used. Such solvents include aromatic hydrocarbons such as toluene and xylene, alcohol
such as methanol, ethanol, and isopropyl alcohol, esters such as ethyl acetate, ethyl
cellosolve, methyl cellosolve, butyl cellosolve, and other cellosolve acetate, and ketones
such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexane. A single kind of
solvent may be used or a mixture of two or more kinds of solvents may be used. As
required, known additives such as a leveling agent, an antifoamer, a surface conditioner,
and a delusterant may be further added to the light-transmitting resin coating composition.
Like the above described undercoat layer 12, the light-transmitting resin coating
composition is applied as a coating to an object by spraying, dipping, or other method and
then cured by e.g. infrared radiation, heated air, ultraviolet radiation, or electron radiation,
whereby the topcoat layer 14 is formed.
[0052]
Referring now to FIG. 3, a modified example of the light reflecting member
according to this embodiment. In a light reflecting member 1 according to this modified
example, silica particles or acrylic particles are added as a light diffusing agent 15 to an
undercoat layer 12 or a light-transmitting resin coating composition that makes up a
topcoat layer 14 according to the above described embodiment. The silica particles or
acrylic particles are white fine powder with average particle size of 10 um or less, and the
surfaces may be treated with silicone oil or the like. In the illustrated example, the light
diffusing agent 15 is added to the undercoat layer 12.
[0053]
The amount of added silica particles or acrylic particles is preferably, but not
limited to, 2 to 10 mass% of the coating composition (solid content). If this range is
exceeded, the reflectance of the light reflecting member is extremely reduced and thus the
effect of use of Ag or Ag base alloy as a light reflecting layer cannot be achieved. On the
other hand, the amount of added silica particles or acrylic particles is below the above
range, a sufficient light diffusion property cannot be achieved.
[0054]
Referring now to FIG. 4, another modified example of the light reflecting member
according to this embodiment is described. In a light reflecting member 1 according to
this modified example, a metal layer 16 of 0.005 to 0.5 um that contains transition metal or
metal.oxide is formed between a light reflecting layer 13 and a topcoat layer 14 according
to the above described embodiment. By forming this metal layer 16, the effect of
inhibiting aggregation of Ag in the light reflecting layer 13 by the action of e.g. heat or fight
can be exhibited so that the fight resistance can be further enhanced.
[0055]
Examples 1 to 21 of light reflecting members 1 according to this embodiment are
described more specifically below. The material compositions of Examples 1 to 8 are
shown in Table 1 below, the material compositions of Examples 9 to 16 are shown in Table
2 below, the material compositions of Examples 17 to 23 are shown in Table 3 below, and
the material compositions of Examples 24 and 25 are shown in Table 4 below.
[0056]
(Example l)
The configuration of a fight reflecting member 1 of Example 1 is shown in FIG. 2
described above. A substrate 11 of an Al (1050) material formed into the shape of the fight
reflecting member 1 (see FIG. l) by spinning is degreased with an alkaline cleaner. Then,
as an undercoat layer 12, 100 parts by mass of a reactive vinyl polymer having basic
nitrogen atoms (ACRYDIC A-9540 manufactured by DIC), 15 parts by mass of a compound
containing hydrolysable silyl groups and epoxy groups (ACRYDIC A-9585 manufactured by
DIC), 0.5 parts by mass of 2-(Benzothiazolylthio)- succinic acid (Irgacor 252 manufactured
by BASF), 100 parts by mass of xylene, 30 parts by mass of isopropyl alcohol, and 20 parts
by mass of butyl acetate are mixed in the proportion, agitated for 5 minutes, and then
applied as a coating by spraying so as to have a thickness of 12um and dried at 70°C for 20
minutes, whereby the undercoat layer 12 is formed. After the undercoat layer 12 is
formed, Ag (99.99 % purity) is DC-magnetron sputtered in an argon (Ar) gas atmosphere,
whereby a light reflecting layer 13 with average thickness of 800A is formed.
[0057]
Subsequently, the component (A): 100 parts by mass of an acrylic resin (ACRYDIC
A814 manufactured by DIC, non-volatile content 50%), the component (B): 28 parts by
mass of a butylated melamine resin (Yuban 225 manufactured by Mitsui Chemicals,
Incorporated, non-volatile content 60%), and the component (C)- 1 part by mass of an
epoxy-containing silane compound (KBM 403 manufactured by Shin-Etsu Chemical Co.,
Ltd, non-volatile content 100%) are mixed and further combined with 60 parts by mass of
butyl acetate, 60 parts by mass of ethyl acetate, and 60 parts by mass of normal butanol in
the proportion. The mixture is agitated for 5 minutes and then applied as a coating by
spraying so as to have a thickness of 12pm and dried at 150°C for 30 minutes, whereby a
topcoat layer 14 is formed. Thus, the light reflecting member 1 of Example 1 is produced.
[0058]
(Example 2)
A light reflecting member 1 of Example 2 is produced in a manner similar to that
in the above Example 1, except that the content of butylated melamine resin (Yuban 225
manufactured by Mitsui Chemicals, Incorporated) in the material composition of a topcoat
layer 14 is 65 parts by mass.
[0059]
(Example 3)
A light reflecting member 1 of Example 3 is produced in a manner similar to that
in the above Example 1, except that the content of butylated melamine resin (Yuban 225
manufactured by Mitsui Chemicals, Incorporated) in the material composition of a topcoat
layer 14 is 20 parts by mass.
[0060]
(Example 4)
A light reflecting member 1 of Example 4 is produced in a manner similar to that
in the above Example 1, except that the content of epoxy-containing silane compound
(KBM 403 manufactured by Shin-Etsu Chemical Co., Ltd.) in the material composition of a
topcoat layer 14 is 4.5 parts by mass.
[0061]
(Example 5)
A light reflecting member 1 of Example 5 is produced in a manner similar to that
in the above Example 1, except that the content of epoxycontaining silane compound
(KBM 403 manufactured by Shin-Etsu Chemical Co., Ltd.) in the material composition of a
topcoat layer 14 is 0.08 parts by mass.
[0062]
(Example 6)
A light reflecting member 1 of Example 6 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 2.6
parts by mass of a triazole ultraviolet absorber (TINUVIN 384-2 manufactured by BASF,
non-volatile content 95%) and 2.9 parts by mass of a triazine ultraviolet absorber
(TINUVIN 400 manufactured by BASF, non-volatile content 85%) are further contained as
the component (D).
[0063]
(Example 7)
A light reflecting member 1 of Example 7 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 4.7
parts by mass of a triazole ultraviolet absorber (TINUVIN 384-2 manufactured by BASF)
and 5.3 parts by mass of a triazine ultraviolet absorber (TINUVIN 400 manufactured by
BASF) are further contained as the component (D).
[0064]
(Example 8)
A light reflecting member 1 of Example 8 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 0.26
parts by mass of a triazole ultraviolet absorber (TINUVIN 384-2 manufactured by BASF)
and 0.29 parts by mass of a triazine ultraviolet absorber (TINUVIN 400 manufactured by
BASF) are further contained as the component (D).
[0065]
(Example 9)
A light reflecting member 1 of Example 9 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 0.5
parts by mass of an organic sulfonic acid (CAT 6000 manufactured by Mitsui Chemicals,
Incorporated, non-volatile content 40%) is further contained as the component (E).
[0066]
(Example 10)
A light reflecting member 1 of Example 10 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 4
parts by mass of an organic sulfonic acid (CAT 6000 manufactured by Mitsui Chemicals,
Incorporated) is further contained as the component (E).
[0067]
(Example 11)
A light reflecting member 1 of Example 11 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 0.1
part by mass of an organic sulfonic acid (CAT 6000 manufactured by Mitsui Chemicals,
Incorporated) is further contained as the component (E).
[0068]
(Example 12)
A light reflecting member 1 of Example 12 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 45
parts by mass of a fluorine resin (ZX 001 manufactured by Fuji Kasei Kogyo Co., Ltd.,
non-volatile content 35%) is further contained as the component (F).
[0069]
(Example 13)
Alight reflecting member 1 of Example 13 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 135
parts by mass of a fluorine resin (ZX 001 manufactured by Fuji Kasei Kogyo Co., Ltd.) is
further contained as the component (F).
[0070]
(Example 14)
Alight reflecting member 1 of Example 14 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 50
parts by mass of a fluorine resin (KD 220 manufactured by Kanto Denka Kogyo Co., Ltd.,
non-volatile content 30%) is further contained as the component (F).
[0071]
(Example 15)
Alight reflecting member 1 of Example 15 is produced in a manner similar to that
in the above Example 1, except that 17 parts by mass of a methylated melamine resin
(Cymel 303 manufactured by Cytec, non-volatile content 100%) is contained as the
melamine resin (B) in the material composition of a topcoat layer 14 and 0.5 parts by mass
of an organic sulfonic acid (CAT 6000 manufactured by Mitsui Chemicals, Incorporated) is
further contained as the component (F).
[0072]
(Example 16)
A light reflecting member 1 of Example 16 is produced in a manner similar to that
in the above Example 1, except that, as the epoxy-containing silane compound (C) in the
material composition of_ a topcoat layer 14, 2 parts by mass of Marproof G-01100
(manufactured by NOF CORPORATION, non-volatile content 100%) is contained in place
ofKBM403.
[0073]
(Example 17)
Alight reflecting member 1 of Example 17 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 150
parts by mass of a fluorine resin (KD 220 manufactured by Kanto Denka Kogyo Co., Ltd.)
is contained as the component (F).
[0074] -
(Example 18)
Alight reflecting member 1 of Example 18 is produced in a manner similar to that
in the above Example 1, except that, as the epoxy-containing silane compound (C) in the
material composition of a topcoat layer 14, 4.5 parts by mass of Marproof G-01100
(manufactured by NOF CORPORATION) is contained in place of KBM 403.
[0075]
(Example 19)
Alight reflecting member 1 of Example 19 is produced in a manner similar to that
in the above Example 1, except that, as the epoxy-containing silane compound (C) in the
material composition of a topcoat layer 14, 0.08 parts by mass of Marproof G-01100
(manufactured by NOF CORPORATION) is contained in place of KBM 403.
[0076]
(Example 20)
A light reflecting member 1 of Example 20 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 2
parts by mass of silica particles (Sylysia 430 manufactured by Fuji Silysia Chemical Ltd.)
are further contained as other component.
[0077]
(Example 21)
A light reflecting member 1 of Example 21 is produced in a manner similar to that
in the above Example 1, except that, in the material composition of a topcoat layer 14, 2
parts by mass of acrylic particles (MBX-5 manufactured by Sekisui Plastics Co., Ltd.) are
further contained as other component.
[0078]
(Example 22)
A light reflecting member 1 of Example 22 is produced in a manner similar to that
in the above Example 7, except that, in the material composition of a topcoat layer 14, 2
parts by mass of a hindered amine light stabilizer (TINUVIN 123 manufactured by BASF,
non-volatile content 100%) is further contained as the component (G).
[0079]
(Example 23)
A light reflecting member 1 of Example 23 is produced in a manner similar to that
in the above Example 7, except that, in the material composition of a topcoat layer 14, 2
parts by mass of a benzoate light stabilizer (TINUVIN 120 manufactured by BASF,
non-volatile content 100%) is further contained as the component (G).
[0080]
(Example 24)
A light reflecting member 1 of Example 24 is produced in a manner similar to that
in the above Example 7, except that, in the material composition of a topcoat layer 14, 6
parts by mass of a hindered amine light stabilizer (TINUVIN 123 manufactured by BASF,
non-volatile content 100%) is further contained as the component (G).
[0081]
(Example 25)
A light reflecting member 1 of Example 25 is produced in a manner similar to that
in the above Example 7, except that, in the material composition of a topcoat layer 14, 6
parts by mass of a benzoate light stabilizer (TINUVIN 120 manufactured by BASF,
non-volatile content 100%) is further contained as the component (G).
[0082]'
Next, Comparative Examples 1 to 11, which are compared with the above
Examples 1 to 25, are described. The material compositions of Comparative Examples 1
to 8 are shown in Table 5 below and the material compositions of Examples 9 to 11 are
shown in Table 6 below.
[0083]
(Comparative Example l)
A light reflecting member of Comparative Example 1 is produced in a manner
similar to that in the above Example 1, except that the content of butylated melamine
resin (Yuban 225 manufactured by Mitsui Chemicals, Incorporated) as the component (B)
in the material composition of a topcoat layer 14 is 80 parts by mass.
[0084]
(Comparative Example 2)
A light reflecting member of Comparative Example 2 is produced in a manner
similar to that in the above Example 1, except that the content of butylated melamine
resin (Yuban 225 manufactured by Mitsui Chemicals, Incorporated) as the component (B)
in the material composition of a topcoat layer 14 is 10 parts by mass.
[0085]
(Comparative Example 3)
A light reflecting member of Comparative Example 3 is produced in a manner
similar to that in the above Example 1, except that no butylated melamine resin (Yuban
225, manufactured by Mitsui Chemicals, Incorporated) as the component (B) in the
material composition of a topcoat layer 14 is added.
[0086]
(Comparative Example 4)
A light reflecting member of Comparative Example 4 is produced in a manner
similar to that in the above Example 1, except that the content of epoxy-containing silane
compound (KBM 403 manufactured by Shin-Etsu Chemical Co., Ltd.) as the component (C)
in the material composition of a topcoat layer 14 is 6 parts by mass.
[0087]
(Comparative Example 5)
A light reflecting member of Comparative Example 5 is produced in a manner
similar to that in the above Example 1, except that the content of epoxy-containing silane
compound (KBM 403 manufactured by Shin-Etsu Chemical Co., Ltd.) as the component (C)
in the material composition of a topcoat layer 14 is 0.04 parts by mass.
[0088]
(Comparative Example 6)
A light reflecting member of Comparative Example 6 is produced in a manner
similar to that in the above Example 1, except that no epoxy-containing silane compound
(KBM 403 manufactured by Shin-Etsu Chemical Co., Ltd.) as the component (C) in the
material composition of a topcoat layer 14 is added.
[0089]
(Comparative Example 7)
A light reflecting member of Comparative Example 7 is produced in a manner
similar to that in the above Example 1, except that, in the material composition of a
topcoat layer 14, 6.3 parts by mass of a triazole ultraviolet absorber (TINUVIN 384-2
manufactured by BASF) and 7.1 parts by mass of a triazine ultraviolet absorber (TINUVIN
400 manufactured by BASF) are further contained as the component (D).
[0090]
(Comparative Example 8)
A light reflecting member of Comparative Example 8 is produced in a manner
similar to that in the above Example 1, except that, in the material composition of a
topcoat layer 14, 6 parts by mass of an organic sulfonic acid (CAT 6000 manufactured by
Mitsui Chemicals, Incorporated) is further contained as the component (E).
[0091]
(Comparative Example 9)
A light reflecting member of Comparative Example 11 is produced in a manner
similar to that in the above Example 1, except that, in the material composition of a
topcoat layer 14, 150 parts by mass of a fluorine resin (ZX 001 manufactured by Fuji Kasei
Kogyo Co., Ltd.) is further contained as the component (F).
[0092]
(Comparative Example 10)
As the material that makes up a topcoat layer 14, an acrylic lacquer (A-190
manufactured by DIC, non-volatile content 50%) is used.
[0093]
(Comparative Example 11)
A light reflecting member of Comparative Example 11 is produced in a manner
similar to that in the above Example 1, except that a straight silicone resin (SH-804
manufactured by Dow Corning Toray Co., Ltd.) is used as the material for a topcoat layer
14.
[0094]
For the light reflecting members according to the Examples and the Comparative
Examples produced as described above, reflectance measurements, adhesion tests after
immersion in boiling water, heat resistance tests, light resistance tests, corrosion
resistance tests, and gas barrier resistance tests have been carried out. The test methods
are shown below. The evaluation results of the tests are shown in Table 1 to Table 6
below.
[0095]
As the reflectance of each light reflecting member (sample), the reflectance at 555
nm is measured using a recording spectrophotometer U-4000 manufactured by Hitachi
High-Technologies Corporation.
(Criteria)
80 % or more: O
Less than 80%: x
[0096]
In the adhesion test after immersion in boiling water, water is boiled in a 20 liter
container of stainless steel placed on a hot plate, and a sample is immersed in it for one
hour. Then, after eleven lengthwise and crosswise cuts 1 mm apart are made with a
cutter knife, the percentage of sample surface that is not peeled with adhesive tape is
evaluated.
(Criteria)
100/100: O
51-99/100: A
0-50/100: x
[0097]
In the heat resistance test, a sample is left in a hot air circulating tank kept at
150°C and the reflectances after 30 days and after 450 days are measured.
(Criteria)
80% or more: O
Less than 80%: x
[0098]
In the light resistance test, a sample is left with a mercury lamp lighted in the
atmosphere of 120°C, and the reflectances after 30 days and after 450 days are measured.
(Criteria)
80% or more: O
Less than 80%: x
[0099]
In the corrosion resistance test, 7 cycles of salt spray tests (saltwater
concentration of 5%, spray for 8 hours, stop of 16 hours) are performed in conformity with
JIS Z 2371, Methods, of salt spray testing, and then the sample is removed for
measurement of the reflectance.
(Criteria)
80% or more: O
Less than 80%: x
[0100]
In the gas barrier property test, 1 g of potassium sulfide and 10 g of water in a
sample tube are placed in a desiccator together with a sample. The sample is taken out
after 24 hours and after 200 hours with the temperature kept at 90 degrees and the.
reflectance is measured.
(Criteria)
80% or more: O
Less than 80%: x
[0101]
In the discoloration resistance test, a sample, which is formed on a 100 mm square
anodized plate so that the resin composition is 100 um thick, is left for 100 days with a
mercury lamp lighted in the atmosphere of 120°C, and the color difference from the initial
stage is measured by a spectrophotometric system and evaluated at AEab.
(Criteria)
Less than 1: ©
Not less than 1 and less than 3: O
Not less than 3 and less than 5: A
5 or more: x

The comparison of Examples 1 to 3 and 15 with Comparative Examples 1 to 3
shows the following. It is preferable that the component (B) is 20 to 80 parts by mass,
more preferably 20 to 65 parts by mass, of a melamine resin per the solid content of the
aery he resin (A). Especially, if the component (B) is not contained, the heat resistance,
light resistance, and gas barrier property are significantly decreased as is obvious from
Comparative Example 3. Further, according to the comparison of Examples 1, 4, 5, 16, 18,
and 19 with Comparative Examples 4 to 6, it is preferable that the component (C) is 0.08 to
10 parts by mass, more preferably 1 to 4.5 parts by mass, of an epoxy-containing silane
compound or acrylic resin per 100 parts by mass of the solid content of the acrylic resin (A).
Especially, if the component (C) is not contained, the adhesion is significantly decreased as
is obvious from Comparative Example 6.
[0109]
Further, the comparison of Examples 6 to 8 with Comparative Example 7 shows
the following. It is preferable that the component (D) is a total of 0.1 to 20 parts by mass,
more preferably 0.55 to 10 parts by mass, of a triazole ultraviolet absorber and/or a
triazine ultraviolet absorber per 100 parts by mass of the solid content of the acrylic resin
(A).
[0110]
.. Further, the comparison of Examples 1 and 9 to 11 with Comparative Example 8
shows the following. It is preferable that the component (E) is 0.1 to 10 parts by mass,
more preferably 0.1 to 4 parts by mass, of an organic sulfonic acid per 100 parts by mass of
the solid content of the acrylic resin (A). By containing this component (E), the gas
barrier property can be improved.
[0111]
Further, the comparison of Examples 12 to 14 and 17 with Comparative Example
9 shows the following. It is preferable that the component (F) is 1 to 150 parts by mass,
more preferably 45 to 135 parts by mass, of a fluorine resin that has fluoroalkylene groups
or perfluoroalkyl groups in the skeleton and has hydroxyl groups as cross linking sites, per
100 parts by mass of the solid content of the aery he resin (A). By containing this
component (F), the heat resistance and the light resistance can be improved.
[0112]
Additionally, Examples 20 and 21 have improved light diffusion properties by
containing silica particles or acrylic particles as other components. Evaluation of light
diffusion properties has not been carried out here. In these Examples, the gas barrier
properties are slightly improved. Comparative Examples 10 and 11, which have main
components different from those of Examples 1 to 21, have low gas barrier properties.
[0113]
Examples 22 and 23 have further improved resistance to discoloration as
compared to Example 7 by containing 4% of a light stabilizer as the component (G) relative
to the solid content of the component (A). Since radicals generated in the resin by
exposure of the resin composition to light and heat are deactivated and thus the resin is
chemically stabilized, discoloration of the resin can be reduced.
[0114]
Examples 24 and 25, which contain 12% of a light stabilizer as the component (G)
relative to the solid content of the component (A), have low gas barrier properties as
compared to Examples 22 and 23 but exhibit excellent resistance to discoloration. In
order to sufficiently secure the maintenance of gas barrier properties, it is preferable that
the amount of light stabilizer added as the component (G) is 0.1 to 10 parts by mass per
100 parts by mass of the solid content of the acrylic resin (A).
[0115]
The prevent invention is not limited to the above described embodiment but
various modifications may be made. For example, it is possible to make multiple topcoat
layers 14 and use different hght-transmitting resin coating compositions, which are
described above, for the respective topcoat layers 14. Further, the hght-transmitting resin
coating composition is used for the topcoat layer 14 in the above described embodiment,
but it may be used for an undercoat layer 12. Moreover, the example in which the metal
layer 16 is formed between the light reflecting layer 13 and the topcoat layer 14 is shown,
but another layer, e.g. a light diffusion layer or a layer to adjust coating thickness, may be
formed in place of or in addition to the metal layer 16.
[0116]
This application is based on Japanese Patent Application No. 2010-179761, the
content of which is incorporated herein by reference.
DESCRIPTION OF REFERENCE NUMERALS
[0117]
1 light reflecting member
2 lighting apparatus
3 light source
11 substrate
12 undercoat layer
13 light reflecting layer
14 topcoat layer
15 silica particles or acrylic particles
CLAIMS
1. A light-transmitting resin coating composition comprising the following
components'
(A) an acrylic resin having hydroxyl groups as cross-linking sites;
(B) 20 to 80 parts by mass of a melamine resin per 100 parts by mass of solid
content of the acrylic resin (A); and
(C) 0.1 to 10 parts by mass of an epoxy-containing silane compound or acrylic resin
per 100 parts by mass of the solid content of the acrylic resin (A).
2. The light-transmitting resin coating composition according to claim 1, further
comprising-
(D) a total of 0.1 to 20 parts by mass of a triazole ultraviolet absorber and/or a
triazine ultraviolet absorber per 100 parts by mass of the solid content of the acrylic resin
(A).
3. The light-transmitting resin coating composition according to claim 1 or 2, further
comp rising:
(E) 0.1 to 10 parts by mass of an organic sulfonic acid per 100 parts by mass of the
solid content of the acrylic resin (A).
4. The light-transmitting resin coating composition according to any one of claims 1
to 3, wherein
the melamine resin (B) comprises a methylated melamine resin.
5. The light-transmitting resin coating composition according to any one of claims 1
to 4, further comprising:
(F) 1 to 100 parts by mass of a fluorine resin, which has fluoroalkylene groups or
perfLuoroalkyl groups in a skeleton and has hydroxyl groups as cross-Unking sites, per 100
parts by mass of the solid content of the acrylic resin (A).
6. The light-transmitting resin coating composition according to any one of claims 1
to 5, further comprising:
(G) 0.1 to 10 parts by mass of at least either a hindered amine light stabilizer or a
benzoate light stabilizer per 100 parts by mass of the solid content of the acrylic resin (A).
7. Alight reflecting member comprising a substrate, a light reflecting layer formed of
Ag or Ag base alloy on the substrate, and a topcoat layer formed on the light reflecting
layer, wherein
the topcoat layer comprises the light-transmitting resin coating composition
according to any one of claims 1 to 6.
8. A light reflecting member comprising a substrate, an undercoat layer formed on a
surface of the substrate, a light reflecting layer formed of Ag or Ag base alloy on the
undercoat layer, and a topcoat layer formed on the light reflecting layer, wherein
the topcoat layer comprises the light-transmitting resin coating composition
according to any one of claims 1 to 6.
9. The light reflecting member according to claim 7 or 8, wherein the topcoat layer
comprises silica particles or acrylic particles.
10. A lighting apparatus comprising a light source and the light reflecting member
according to any one of claims 7 to 9 that reflects light from the light source.