Resin composition for translucent cover, translucent cover, and luminaire

Abstract

To provide a novel resin composition for a translucent cover capable of forming a resin layer that is highly resistant to chemicals and capable of adhering to a resin layer containing polycarbonate resin.SOLUTION: There is provided a resin composition for forming a resin layer constituting a translucent cover by bonding to a resin layer containing a polycarbonate resin, wherein the resin composition contains (a) a polypropylene-based resin and (b) an ethylene methyl acrylate copolymer, and when a total amount of the (a) and the (b) is 100 pts. mass, the resin composition contains 35 pts. mass or more and 65 pts. mass or less of the (a) and 35 pts. mass or more and 65 pts. mass or less of the (b).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition for a light-transmitting cover, a light-transmitting cover, and a lighting fixture. [Background technology]

[0002] Patent Document 1 discloses a composition consisting essentially of about 10 to about 80, or 40 to 80 weight % of at least one ethylene / alkyl(meth)acrylate copolymer; (b) about 5 to about 60, or 20 to 60, or 20 to 40 weight % of at least one polyolefin; 0 to about 35, or 0.5 to 35, or 10 to 20 weight % of at least one tackifying resin; and 0 to about 35, or 5 to 20 weight % of a filler, wherein the alkyl group in the alkyl(meth)acrylate preferably has 1 to 4 carbon atoms, and the ethylene / alkyl(meth)acrylate copolymer preferably contains 5 to 30 weight % of repeating units derived from alkyl(meth)acrylate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2007-522276 Summary of the Invention [Problem to be solved by the invention]

[0004] Polycarbonate resin is used as a resin constituting a light-transmitting cover member for a lighting fixture. From the viewpoint of improving the chemical resistance of the light-transmitting cover member, a resin composition that can form a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin is desired.

[0005] An object of one aspect of the present invention is to provide a novel resin composition for a light-transmitting cover, which is capable of forming a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin. [Means for solving the problem]

[0006] As a result of intensive research to solve the above problems, the present inventors have found for the first time that a resin composition containing a specific amount of a polypropylene resin and an ethylene methyl acrylate copolymer can form a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin.The present inventors have also found for the first time that such a resin composition can be suitably used to form a resin layer that constitutes a light-transmitting cover by adhering it to a resin layer containing a polycarbonate resin, and have completed the present invention.

[0007] That is, in order to solve the above-mentioned problems, a resin composition for a translucent cover according to one embodiment of the present invention is a resin composition for forming a resin layer that constitutes a translucent cover by adhering to a resin layer containing a polycarbonate resin, and is characterized in that the resin composition contains (a) a polypropylene-based resin and (b) an ethylene methyl acrylate copolymer, and when the total amount of the (a) polypropylene-based resin and the (b) ethylene methyl acrylate copolymer is 100 parts by mass, the resin composition contains 35 parts by mass or more and 65 parts by mass or less of the (a) polypropylene-based resin and 35 parts by mass or more and 65 parts by mass or less of the (b) ethylene methyl acrylate copolymer. [Effects of the Invention]

[0008] According to one aspect of the present invention, a novel resin composition for a light-transmitting cover can be provided, which is capable of forming a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin. DETAILED DESCRIPTION OF THE INVENTION

[0009] One embodiment of the present invention will be described in detail below. In this specification, unless otherwise specified, the expression "A to B" representing a range of numerical values means "A or more and B or less."

[0010] [1. Resin composition] A resin composition for a light-transmitting cover according to one embodiment of the present invention is a resin composition for forming a resin layer that constitutes a light-transmitting cover by adhering to a resin layer containing a polycarbonate resin, and the resin composition contains (a) a polypropylene-based resin (hereinafter also referred to as "component (a)") and (b) an ethylene methyl acrylate copolymer (hereinafter also referred to as "EMA" or "component (b)"), and when the total amount of the (a) polypropylene-based resin and the (b) ethylene methyl acrylate copolymer is 100 parts by mass, the resin composition contains 35 parts by mass or more and 65 parts by mass or less of the (a) polypropylene-based resin and 35 parts by mass or more and 65 parts by mass or less of the (b) ethylene methyl acrylate copolymer.

[0011] The resin composition for a translucent cover according to one embodiment of the present invention contains the components (a) and (b) in the specific amounts described above, thereby realizing a resin composition that can form a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin. In this specification, the "resin composition for a translucent cover" may also be simply referred to as the "resin composition."

[0012] <(a) Polypropylene Resin> The polypropylene resin used in one embodiment of the present invention is at least one selected from a propylene homopolymer and a copolymer of propylene and another olefin. From the viewpoint of resin strength, the content of propylene structural units in the polypropylene resin is preferably as high as possible, for example, 80 mol% or more.

[0013] The type of polypropylene-based resin is not particularly limited, and examples thereof include propylene-based polymers selected from propylene homopolymers, propylene-ethylene block copolymers, propylene-butene block copolymers, propylene-α-olefin block copolymers, propylene-ethylene random copolymers, propylene-butene random copolymers, propylene-α-olefin random copolymers, and propylene-α-olefin graft copolymers. From the viewpoint of resin strength, propylene homopolymers are preferred. One type of polypropylene-based resin may be used alone, or two or more types may be used in combination.

[0014] When the polypropylene-based resin is a copolymer, the olefin other than propylene that can be contained as a structural unit includes at least one selected from the group consisting of ethylene and α-olefins having 4 to 30 carbon atoms. Examples of the α-olefin include 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. The content of the structural unit of the olefin other than propylene in the polypropylene-based resin is not particularly limited.

[0015] The polypropylene resin may be an unmodified polypropylene resin or an acid-modified polypropylene resin, and a maleic acid-modified polypropylene resin is more preferred. In this specification, the maleic acid-modified polypropylene resin may be referred to as a "maleic acid-modified polypropylene resin" or "component (c)".

[0016] The polypropylene resin and the maleic acid-modified polypropylene resin can be produced by a conventional synthesis method, for example, according to the synthesis method described in Japanese Patent No. 7129129.

[0017] (Content of component (a) and component (c)) A resin composition according to one embodiment of the present invention contains 35 parts by mass or more and 65 parts by mass or less of component (a) when the total amount of components (a) and (b) is 100 parts by mass, thereby providing a resin composition that can form a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin.

[0018] From the viewpoint of the chemical resistance of the resulting resin, the content of component (a) is preferably 40 parts by mass or more, and more preferably 50 parts by mass or more, when the total amount of components (a) and (b) is 100 parts by mass. Also, from the viewpoint of adhesion to a resin layer containing a polycarbonate resin, the content of component (a) is preferably 60 parts by mass or less, and more preferably 55 parts by mass or less, when the total amount of components (a) and (b) is 100 parts by mass.

[0019] Furthermore, when the resin composition according to an embodiment of the present invention includes component (c) as component (a), from the viewpoint of optical performance, the content of component (c) is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, when the total amount of components (a) and (b) is 100 parts by mass. Furthermore, from the viewpoint of extrusion moldability, the content of component (c) is preferably 6 parts by mass or less, more preferably 5 parts by mass or less, when the total amount of components (a) and (b) is 100 parts by mass.

[0020] <(b) Ethylene methyl acrylate copolymer> The ethylene methyl acrylate copolymer is a copolymer of ethylene and methyl acrylate. The content of methyl acrylate structural units in the EMA used in one embodiment of the present invention is not particularly limited.

[0021] EMA can be produced by conventional synthesis methods, for example, according to the synthesis method described in Patent Document 1.

[0022] ((b) Content of ingredients) A resin composition according to one embodiment of the present invention contains 35 parts by mass or more and 65 parts by mass or less of component (b) when the total amount of components (a) and (b) is 100 parts by mass, thereby providing a resin composition that can form a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin.

[0023] From the viewpoint of adhesion to a resin layer containing a polycarbonate resin, the content of component (a) is preferably 40 parts by mass or more, and more preferably 50 parts by mass or more, when the total amount of components (a) and (b) is 100 parts by mass. Furthermore, from the viewpoint of chemical resistance of the resulting resin, the content of component (b) is preferably 60 parts by mass or less, and more preferably 55 parts by mass or less, when the total amount of components (a) and (b) is 100 parts by mass.

[0024] The total content of components (a) and (b) in the resin composition according to one embodiment of the present invention is 98% by mass or more, preferably 99% by mass or more, based on the total amount (100% by mass) of the resin composition. The upper limit of the total content of components (a) and (b) is, for example, 100% by mass or less, preferably less than 100% by mass, more preferably 99.9% by mass or less, and even more preferably 99.8% by mass or less.

[0025] <Antioxidants> In addition to the above-described components, the resin composition according to one embodiment of the present invention may contain an antioxidant within a range that does not impair the effects of the present invention. The antioxidant is a substance that has the function of preventing oxidation of the resin composition according to one embodiment of the present invention. Examples of the antioxidant include conventionally known antioxidants used for the purpose of preventing oxidation of resin compositions, such as phenol compounds, phosphorus compounds, and thioether compounds. These may be used alone or in combination of two or more.

[0026] From the viewpoint of preventing yellowing in a dark place, the resin composition according to one embodiment of the present invention preferably further contains an antioxidant containing a thioether compound (hereinafter also referred to as a "thioether-based antioxidant").

[0027] Examples of the thioether antioxidant include dialkyl thiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and pentaerythritol tetra(β-alkylmercaptopropionate) esters. These may be used alone or in combination of two or more.

[0028] From the viewpoint of sufficiently preventing yellowing of the resin composition according to one embodiment of the present invention in a dark place, the content of the thioether-based antioxidant is preferably within the following range. Specifically, the content of the thioether-based antioxidant is preferably 0.01 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.1 parts by mass or more, when the total amount of the components (a) and (b) is 100 parts by mass. Furthermore, the content of the thioether-based antioxidant is preferably within the following range. Specifically, the content of the thioether-based antioxidant is preferably 2 parts by mass or less, more preferably 1 part by mass or less, and even more preferably 0.8 parts by mass or less, when the total amount of the components (a) and (b) is 100 parts by mass.

[0029] <Other additives> In addition to the above-described components, the resin composition according to one embodiment of the present invention may contain optional additives such as lubricants, weathering agents, and antistatic agents, provided that the effects of the present invention are not impaired. These additives may be additives commonly used in the relevant technical field. The content of the additives in the resin composition may be appropriately adjusted in consideration of the performance of each additive. Furthermore, in consideration of reducing the influence on the physical properties of the resulting molded article, the total content of the additives in the resin composition is preferably 5% by mass or less, and more preferably 3% by mass or less, based on the total amount (100% by mass) of the resin composition.

[0030] <Properties and Form of Resin Composition> The level of adhesion of the resin composition according to one embodiment of the present invention to a resin layer containing a polycarbonate resin is not particularly limited. For example, after forming a laminate in which a resin layer (first resin layer) made of the resin composition according to one embodiment of the present invention and a resin layer (second resin layer) containing a polycarbonate resin are bonded by a heat press bonding method, it is preferable that the second resin layer does not peel off from the first resin layer when an incision is made in the laminate. In this evaluation test, an incision is made in the laminate so as to cut the laminate in the stacking direction of the first and second resin layers. The presence or absence of peeling between the second resin layer and the first resin layer is confirmed by visually observing the incised cross section of the laminate.

[0031] Resin compositions that do not cause peeling between the second resin layer and the first resin layer in the above evaluation tests have good adhesion to resin layers containing polycarbonate resin, and therefore such resin compositions can be suitably used as resin compositions for forming a resin layer on the surface of a resin layer containing polycarbonate resin in a translucent cover.

[0032] Although the level of chemical resistance of the resin composition according to one embodiment of the present invention is not particularly limited, for example, the resin composition according to one embodiment of the present invention preferably has a critical strain of 0.6% or more as measured by a chemical crack test method. Since a resin composition having a critical strain of 0.6% or more has good chemical resistance, such a resin composition can be suitably used as a resin composition for forming a chemical-resistant resin layer on the surface of a resin layer containing a polycarbonate resin in a translucent cover.

[0033] In the present specification, the chemical crack test method is a test in which a dumbbell test piece having a width of 2 cm, a length of 19 cm, and a thickness of 4 mm is obtained by injection molding a resin composition according to an embodiment of the present invention under the conditions of a cylinder temperature of 190°C to 210°C, a mold temperature of 50°C, a cycle time of 30 seconds, and a residence time of 30 seconds, and the dumbbell test piece is attached along the curved surface of a constant strain jig having a predetermined strain (R) (for example, a strain (R) of 0.6%), any one of the following test solutions (i) to (v) is applied to the apex of the curve of the dumbbell test piece, and the dumbbell test piece is left in a thermostatic chamber set at a temperature of 23±2°C and a humidity of 50±5% in a windless state where the dumbbell test piece is not directly exposed to wind for 24 hours, and then the presence or absence of cracks in the appearance of the dumbbell test piece is visually confirmed: (i) 30% by mass aqueous sodium hydroxide solution (ii) Household detergent Glass Magiclean (registered trademark) (Kao Corporation) undiluted solution (iii) Sanpol (registered trademark) (manufactured by Dai Nippon Jochugiku Co., Ltd.) undiluted solution (iv) Lubricant KURE5-56 (registered trademark) (Kure Industries Co., Ltd.) undiluted solution (v) Water-soluble machining oil UC1230DF (registered trademark) (Nippon Machine Oil Co., Ltd.) undiluted solution, The critical strain is the maximum strain (R) among the strains (R) of the constant strain jig used under test conditions where no cracks occur for all of the test liquids (i) to (v).

[0034] The level of the optical properties of the resin composition according to one embodiment of the present invention is not particularly limited, but for example, the resin composition according to one embodiment of the present invention preferably has a total light transmittance of 70% or more, more preferably 75% or more, more preferably 80% or more, and even more preferably 85% or more. The upper limit of the total light transmittance is not particularly limited, but may be, for example, 100% or less, 98% or less, or 95% or less. Resin compositions with a total light transmittance of 70% or more have good optical properties and can therefore be suitably used as resin compositions for translucent covers.

[0035] In this specification, the total light transmittance refers to the total light transmittance of a 2 mm thick plate obtained by injection molding a resin composition according to one embodiment of the present invention under the following conditions: a cylinder temperature of 190°C to 210°C, a mold temperature of 50°C, a cycle time of 30 seconds, and a residence time of 30 seconds. The total light transmittance is measured using a known spectrophotometer. In this specification, the total light transmittance may be simply referred to as "transmittance."

[0036] The level of the optical properties of the resin composition according to one embodiment of the present invention is not particularly limited, but for example, the resin composition according to one embodiment of the present invention preferably has a haze value of 62% or less, more preferably 60% or less, more preferably 55% or less, and even more preferably 50% or less. The lower limit of the haze value is not particularly limited, but may be, for example, 5% or more, 20% or more, or 40% or more. Resin compositions with a haze value of 62% or less have good optical properties and can therefore be suitably used as resin compositions for translucent covers.

[0037] In this specification, the haze value refers to the haze value of a 0.8 mm thick plate obtained by injection molding a resin composition according to one embodiment of the present invention under the following conditions: cylinder temperature: 190 to 210°C, mold temperature: 50°C, cycle time: 30 seconds, and residence time: 30 seconds. The haze value is measured by the method of JIS K 7136:2000.

[0038] The fluidity level of the resin composition according to one embodiment of the present invention is not particularly limited. For example, the melt mass flow rate (MFR) of the resin composition according to one embodiment of the present invention, as measured by JIS K 7210-1 (230°C, 2.16 kg), is preferably 6.0 g / 10 min or less, more preferably 5.0 g / 10 min or less, more preferably 4.0 g / 10 min or less, and even more preferably 3.5 g / 10 min or less. The lower limit of the MFR is not particularly limited, but may be, for example, 0.1 g / 10 min or more, 1.0 g / 10 min or more, or 3.0 g / 10 min or more. Resin compositions with an MFR of 6.0 g / 10 min or less have good fluidity and can be used for extrusion molding.

[0039] In this specification, MFR is measured in accordance with JIS K 7210-1:2019 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0040] The form of the resin composition according to one aspect of the present invention is not particularly limited, and may be any form such as, for example, powder, granules, pellets, etc. The resin composition according to one aspect of the present invention is preferably in the form of pellets, in terms of ease of extrusion molding.

[0041] <Applications of resin composition> The resin composition according to one embodiment of the present invention has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin. Taking advantage of the above-mentioned features, the resin composition according to one embodiment of the present invention can be suitably used as a resin material for forming a resin layer that constitutes a translucent cover by adhering to a resin layer containing a polycarbonate resin. Therefore, the resin composition according to one embodiment of the present invention can be used as a resin composition for a translucent cover.

[0042] <Method of manufacturing resin composition> The resin composition according to one embodiment of the present invention can be produced, for example, by blending and melt-kneading component (a) and component (b). For example, the components can be blended and kneaded using a Henschel mixer, Banbury mixer, single-screw extruder, twin-screw extruder, multi-screw extruder, co-kneader, or the like. The heating temperature during kneading is usually in the range of 20°C to 60°C higher than the melting point of the resin.

[0043] Alternatively, the above components may be compounded and pre-mixed (pre-blended) using a commonly used device (for example, a ribbon blender, a drum tumbler, etc.), and then kneaded using the above device.

[0044] [2.Translucent cover] A light-transmitting cover according to one aspect of the present invention is a light-transmitting cover configured to cover a light source, and the light-transmitting cover is formed by integrally stacking multiple resin layers in the light-emitting direction of the light source. The multiple resin layers constituting the light-transmitting cover according to one aspect of the present invention include a first resin layer formed from the resin composition according to one aspect of the present invention and a second resin layer containing a polycarbonate resin, the first resin layer and the second resin layer being bonded together, and the first resin layer being disposed further outward from the light source than the second resin layer. The resin composition according to one aspect of the present invention in the light-transmitting cover according to one aspect of the present invention has already been described, so description will not be repeated here.

[0045] A light-transmitting cover according to one aspect of the present invention is a laminated molded body having a plurality of resin layers including a first resin layer and a second resin layer, and is configured to cover a light source, allowing light emitted from the light source to pass through the light-transmitting cover according to one aspect of the present invention.

[0046] Further, since the plurality of resin layers of the translucent cover according to one aspect of the present invention are integrally laminated in the light irradiation direction of the light source, a translucent cover according to one aspect of the present invention that makes use of the characteristics of a plurality of resin materials can be realized. Specifically, by forming the second resin layer on the light source side with a polycarbonate resin having characteristics of being difficult to break and difficult to burn, the strength and the non-flammability of the translucent cover itself according to one aspect of the present invention can be ensured. Further, by forming the first resin layer laminated on the outer surface as viewed from the light source than the second resin layer with the resin composition according to one aspect of the present invention, a resin film having good adhesion to the second resin layer containing a polycarbonate resin can be formed on the surface of the second resin layer. Since the first resin layer has excellent chemical resistance, the first resin layer serves as a barrier and it becomes difficult for chemicals to reach the second resin layer. As a result, excellent chemical resistance can be imparted to the translucent cover according to one aspect of the present invention.

[0047] The thickness of the translucent cover according to one aspect of the present invention is not particularly limited and can be set as appropriate. For example, the thickness of the translucent cover can be 0.8 mm or more and 3.0 mm or less. The thickness (T1) of the first resin layer is not particularly limited and can be set as appropriate. For example, the thickness (T1) of the first resin layer can be 0.1 mm or more and 0.5 mm or less.

[0048] Further, the thickness (T2) of the second resin layer is not particularly limited and can be set as appropriate. For example, the thickness (T2) of the second resin layer can be 0.7 mm or more and 2.5 mm or less. From the viewpoint of imparting flame retardancy to the translucent cover according to one aspect of the present invention, the thickness (T2) of the second resin layer is preferably a thickness equal to or greater than the thickness at which it becomes V-0 in the flame retardancy test of the UL94 standard. Thereby, the second resin layer can satisfy the V-0 standard in the flame retardancy test of the UL94 standard.

[0049] In the translucent cover according to one aspect of the present invention, it is preferable that the thickness (T1) of the first resin layer and the thickness (T2) of the second resin layer satisfy T1 < T2. Thereby, a translucent cover with high light extraction efficiency can be provided.

[0050] <Second resin layer> (Polycarbonate resin) The polycarbonate resin contained in the second resin layer is not particularly limited in type, as long as it is a resin containing a polymer having a carbonate bond (-O-CO-O-) in the main chain. The polycarbonate resin may be, for example, an aromatic polycarbonate resin or an aliphatic polycarbonate. The aromatic polycarbonate resin is a polycarbonate resin containing an aromatic ring such as a benzene ring between carbonate bonds in the main chain, and the aliphatic polycarbonate resin is a polycarbonate resin not containing an aromatic ring such as a benzene ring between carbonate bonds in the main chain. The polycarbonate resin may also have a branched structure. One type of polycarbonate resin may be used alone, or two or more types may be used in combination in any ratio.

[0051] The polycarbonate resin may be produced by a known method. For example, the polycarbonate resin may be produced by reacting a dihydric phenol with a carbonate precursor by a solution method (interfacial polycondensation method) or a melting method (ester exchange method), i.e., by the interfacial polycondensation method of reacting a dihydric phenol with phosgene in the presence of a terminal terminator, or by the ester exchange method of reacting a dihydric phenol with diphenyl carbonate or the like in the presence of a terminal terminator.

[0052] The dihydric phenol, carbonate precursor, end-capping agent, etc. that can be used in the production of polycarbonate resins can be those commonly used in the art. For example, the dihydric phenol, carbonate precursor, end-capping agent, etc. disclosed in WO 2018 / 181949 can be used in the production of polycarbonate resins.

[0053] From the viewpoint of moldability, the polycarbonate resin used in one embodiment of the present invention preferably has a melt mass flow rate (MFR) measured by JIS K 7210-1 method (300°C, 2.16 kg) of 15 g / 10 min or less, more preferably 13 g / 10 min or less, and even more preferably 10 g / 10 min or less. The lower limit of the MFR is not particularly limited, but may be, for example, 0.1 g / 10 min or more, 1 g / 10 min or more, or 3 g / 10 min or more. Polycarbonate resins with an MFR of 7 g / 10 min or less have good fluidity and are therefore suitable for use in extrusion molding.

[0054] (Other ingredients) The resin forming the second resin layer may contain, in addition to the polycarbonate resin, any additives such as antioxidants, lubricants, weatherproofing agents, antistatic agents, etc., within the range that does not impair the effects of the present invention. These additives have already been described as additives to be added to the resin composition according to one aspect of the present invention, and therefore will not be described again here.

[0055] <Other resin layers> The light-transmitting cover according to one aspect of the present invention may have a resin layer other than the first resin layer and the second resin layer (hereinafter referred to as "another resin layer"). The other resin layer is preferably disposed more inward than the second resin layer when viewed from the light source. The type of resin forming the other resin layer is not particularly limited and can be appropriately selected depending on the purpose. Examples of resins forming the other resin layer include acrylic resin and polystyrene resin. The light-transmitting cover according to one aspect of the present invention may have one or more other resin layers.

[0056] (Manufacturing method of light-transmitting cover) The light-transmitting cover according to one embodiment of the present invention can be manufactured by a conventional molding method for a resin laminate, such as co-extrusion molding, injection molding, or vacuum molding.

[0057] (Applications of translucent covers) The multiple resin layers constituting the light-transmitting cover according to one embodiment of the present invention include a first resin layer formed from the resin composition according to one embodiment of the present invention and a second resin layer containing a polycarbonate resin. Therefore, the light-transmitting cover according to one embodiment of the present invention has excellent chemical resistance. While the use of the light-transmitting cover according to one embodiment of the present invention is not particularly limited, taking advantage of the above-described features, the cover can be suitably used, for example, as a cover for covering a light source in a device equipped with a light source, such as a lighting fixture or a signboard. Therefore, the light-transmitting cover according to one embodiment of the present invention can be used as a light-transmitting cover for a lighting fixture or a signboard.

[0058] [3. Lighting equipment] A lighting fixture according to an aspect of the present invention includes a light-transmitting cover according to an aspect of the present invention, a light source, and a fixture body in which the light source is installed. The light-transmitting cover according to an aspect of the present invention in the lighting fixture according to an aspect of the present invention has already been described, and therefore will not be described again here.

[0059] The type of light source is not particularly limited, and may be any conventional light source used in lighting fixtures, such as a white light-emitting diode (LED), a fluorescent lamp, or a mercury lamp.

[0060] The specific structure of the fixture body is not particularly limited as long as it is a structure that can accommodate a light source. For example, it can be a structure that is attached to the ceiling with a hanging bolt and detachably holds the light source. Such a structure is disclosed, for example, in Japanese Patent No. 6976164.

[0061] In a lighting fixture according to an aspect of the present invention, the light-transmitting cover according to an aspect of the present invention is attached to a fixture body in which a light source is installed so as to cover the light source.

[0062] (Use of lighting fixtures) The lighting fixture according to one aspect of the present invention has excellent chemical resistance because it includes the light-transmitting cover according to one aspect of the present invention. The lighting fixture according to one aspect of the present invention is not particularly limited in its applications, but by taking advantage of the above-described features, it has excellent resistance to chemicals such as household detergents and commercial detergents, and can therefore be suitably used as a household lighting fixture, a commercial lighting fixture, etc. Furthermore, as a commercial lighting fixture, it can be suitably used in special environments such as food factories, pharmaceutical factories, and machine parts factories where chemicals and oils evaporate and adhere to the lighting device.

[0063] 〔summary〕 A resin composition for a light-transmitting cover according to a first aspect of the present invention is a resin composition for forming a resin layer constituting a light-transmitting cover by adhering to a resin layer containing a polycarbonate resin, The resin composition is (a) a polypropylene-based resin; (b) ethylene methyl acrylate copolymer; Contains When the total amount of the (a) polypropylene resin and the (b) ethylene methyl acrylate copolymer is 100 parts by mass, (a) 35 parts by mass or more and 65 parts by mass or less of a polypropylene-based resin, and (b) 35 parts by mass or more and 65 parts by mass or less of ethylene methyl acrylate copolymer, It is characterized in that it contains

[0064] In the resin composition for a translucent cover according to aspect 2 of the present invention, it is preferable that, in the above-mentioned aspect 1, a laminate is formed by bonding a resin layer made of the resin composition and a resin layer containing the polycarbonate resin by a heat press bonding method, and then when an incision is made in the laminate, the resin layer containing the polycarbonate resin does not peel off from the resin layer made of the resin composition.

[0065] The resin composition for a light-transmitting cover according to Aspect 3 of the present invention, in Aspect 1 or 2, preferably has a total light transmittance of 70% or more.

[0066] The resin composition for a light-transmitting cover according to Aspect 4 of the present invention, in any one of Aspects 1 to 3, preferably has a haze of 62% or less.

[0067] In the resin composition for a light-transmitting cover according to Aspect 5 of the present invention, in any one of Aspects 1 to 4, the critical strain measured by a chemical crack test method is preferably 0.6% or more.

[0068] In the resin composition for a translucent cover according to aspect 6 of the present invention, in any one of aspects 1 to 5, it is preferable that the melt mass flow rate (MFR) measured by the JIS K 7210-1 method (230°C, 2.16 kg) is 6.0 g / 10 min or less.

[0069] A resin composition for a light-transmitting cover according to a seventh aspect of the present invention is the resin composition for a light-transmitting cover according to any one of the first to sixth aspects, further comprising (c) a maleic acid-modified polypropylene resin as the (a) polypropylene-based resin; With respect to 100 parts by mass of the total of the (a) polypropylene resin and the (b) ethylene methyl acrylate copolymer, It is preferable that the (c) maleic acid-modified polypropylene resin is contained in an amount of 2 parts by mass or more and 6 parts by mass or less.

[0070] The resin composition for a light-transmitting cover according to Aspect 8 of the present invention is preferably the resin composition for any one of Aspects 1 to 7, further comprising an antioxidant containing a thioether compound.

[0071] A light-transmitting cover according to a ninth aspect of the present invention is a light-transmitting cover configured to cover a light source, The light-transmitting cover is formed by integrally stacking a plurality of resin layers in the light irradiation direction of the light source, The plurality of resin layers include a first resin layer formed from the resin composition according to any one of Aspects 1 to 8; a second resin layer containing a polycarbonate resin; The first resin layer and the second resin layer are adhered to each other, and the first resin layer is disposed outside the second resin layer as viewed from the light source.

[0072] In the aspect 10 of the present invention, in the aspect 9, it is preferable that the thickness (T1) of the first resin layer and the thickness (T2) of the second resin layer satisfy T1 < T2.

[0073] The lighting fixture according to the aspect 11 of the present invention includes the translucent cover described in the aspect 10, a light source, and a fixture body on which the light source is installed.

[0074] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Example

[0075] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0076] [Raw materials of resin composition] The raw materials of the resin composition used in Examples and Comparative Examples are as follows. <(a) Polypropylene (PP) - based resin> Polypropylene resin (homopolymer, manufactured by Prime Polymer Co., Ltd., trade name "F - 300SP") (c) Maleic acid - modified polypropylene resin (manufactured by SI Group, inc., trade name "POLYBOND TM 3200") <(b) Ethylene - methyl acrylate copolymer> Manufactured by Japan Polyethylene Corporation, trade name "Lex Pearl TM EB050S" <Antioxidant> Thioether - based antioxidant (manufactured by ADEKA Corporation, trade name "Adekastab (registered trademark) AO - 412S")

[0077] [Examples 1 to 10, Comparative Examples 1 to 5] The components were pre-blended at the compounding ratios shown in Table 1 or Table 2. The pre-blended mixture was melt-kneaded using a twin-screw extruder with a screw diameter of 37 mm (Shibaura Machine Co., Ltd., product name "TEM-37SX") with a cylinder temperature set to 180 to 220°C. The strand extruded from the die was cooled on a cooling mesh conveyor and cut with a pelletizer to obtain pellets of the resin composition. Various test pieces were prepared from these pellets using an injection molding machine, and the following evaluations were performed. In Tables 1 and 2, the unit of compounding amount is parts by mass, and the values shown are those when the total amount of the base resin and silica is 100 parts by mass.

[0078] <Injection molding> Injection molding machine (Shibaura Machine Co., Ltd., product name "EC-100SX", mold clamping force: 10kN) Cylinder temperature: 190~210℃ Mold temperature: 50℃

[0079] [evaluation] <Melt Mass Flow Rate (MFR)> (Measurement method) The resin compositions of the examples and comparative examples were measured for MFR at a temperature of 230°C and a load of 2.16 kg in accordance with JIS K 7210-1:2019.

[0080] <Haze> (Test piece) Using pellets of the resin composition of the Examples or Comparative Examples, plate test pieces 10 cm wide, 10 cm long, and 0.8 mm thick were prepared by injection molding under the following conditions: cylinder temperature 190 to 210°C, mold temperature 50°C, cycle time 30 seconds, and residence time 30 seconds.

[0081] (Measurement method) The haze value was measured according to the method of JIS K 7136:2000.

[0082] <Total light transmittance> (Test piece) Using pellets of the resin composition of the Examples or Comparative Examples, plate test pieces 10 cm wide, 10 cm long, and 2 mm thick were prepared by injection molding under the following conditions: cylinder temperature 190 to 210°C, mold temperature 50°C, cycle time 30 seconds, and residence time 30 seconds.

[0083] (Measurement method) The total light transmittance was measured using a spectrophotometer ("UH-4150" manufactured by Hitachi High-Technologies Corporation).

[0084] <Adhesion to polycarbonate (PC) resin> (Test piece) Using pellets of the resin composition of the Examples or Comparative Examples, plate test pieces having a width of 10 cm, a length of 10 cm and a thickness of 2.0 mm were prepared by injection molding. (PC pellets) Mitsubishi Engineering Plastics Corporation, product name "Iupilon TM EKD2113U"

[0085] (Test Method) (1) A PC pellet (a second resin layer containing a PC resin) was placed on a plate specimen (a first resin layer made of a resin composition), and the plate specimen and the PC pellet were bonded together by a heat press bonding method to form a laminate. The heat press bonding method involved melting the plate specimen and the PC pellet for 5 minutes, then pressing them together for 1 minute (280°C, 250 kN), followed by a cooling press (water cooling, 250 kN) for 1.5 minutes. (2) The obtained laminate was cut with scissors, and the cross section of the laminate was visually observed.

[0086] (Judgment criteria) The plate specimen was visually inspected for peeling between the specimen and the PC pellet. Based on the cross-sectional observation results, the adhesion to the PC was evaluated using a three-level score of 1 to 3 according to the following criteria: 3: No peeling is observed on the cross section 2: Peeling is observed in part of the cross section 1: Peeling is observed throughout the cross section A score of 1 indicates no adhesion to the PC, a score of 2 indicates partial adhesion to the PC, and a score of 3 indicates adhesion to the PC.

[0087] <Chemical crack test> A chemical crack test was carried out to evaluate the chemical resistance. (Test solution) The following five test solutions were used: (i) 30% by mass aqueous sodium hydroxide solution (ii) Household detergent Glass Magiclean (registered trademark) (Kao Corporation) undiluted solution (iii) Sanpol (registered trademark) (manufactured by Dai Nippon Jochugiku Co., Ltd.) undiluted solution (iv) Lubricant KURE5-56 (registered trademark) (Kure Industries Co., Ltd.) undiluted solution (v) Water-soluble machining oil UC1230DF (registered trademark) (Nippon Machine Oil Co., Ltd.) undiluted solution

[0088] (Test piece) Using pellets of the resin composition of the Examples or Comparative Examples, dumbbell test pieces measuring 2 cm wide, 19 cm long, and 4 mm thick were prepared by injection molding under the following conditions: cylinder temperature of 190 to 210°C, mold temperature of 50°C, cycle time of 30 seconds, and residence time of 30 seconds.

[0089] (Test Method) (1) A dumbbell test piece was attached along the curved surface of a constant strain jig with a strain (R) of 0.6%. (2) The test liquid was dropped or applied near the apex of the curve of the dumbbell test piece. The amount of the test liquid dropped or applied was 0.5 ml / cm. 2 was used as a guideline. (3) The dumbbell test pieces were left in a thermostatic chamber set at a temperature of 23±2°C and a humidity of 50±5% for 24 hours in a windless environment where the dumbbell test pieces were not exposed to direct wind.

[0090] (4) Chemical substances (components contained in the test solution) adhering to the surface of the dumbbell test piece were wiped off with a soft cloth or the like. (5) The appearance was visually inspected to check for crazes, deterioration, or cracks. Each test solution was tested separately.

[0091] (Judgment criteria) If cracks were not visually observed, the critical strain was determined to be 0.6% or more. On the other hand, if cracks were visually observed, the critical strain was determined to be less than 0.6%. For each test solution, it was determined whether the critical strain was 0.6% or more.

[0092] Based on the results for each test solution, the chemical resistance was evaluated using a two-level score of 1 to 2 according to the following criteria. 2: Critical strain is 0.6% or more for all five test liquids 1: Critical strain is less than 0.6% for at least one of the five test solutions A score of 1 indicates poor chemical resistance, and a score of 2 indicates good chemical resistance.

[0093] <Overall Judgment> Based on the evaluation results of adhesion to PC and chemical resistance, the samples were evaluated using a three-level score of 1 to 3 according to the following criteria. 3: Adhesion to PC is good and chemical resistance is excellent 2: Partial adhesion to PC and good chemical resistance 1: No adhesion to PC or chemical resistance

[0094] <Extrusion moldability> (Test Method) The translucent cover member was formed by multi-color extrusion molding. Specifically, resin materials were melted in an extruder, and the melted resin materials were merged in a mold and integrated in the molten state to obtain the translucent cover member. The extrusion molding was performed under the following temperature conditions. <Temperature conditions for extrusion molding> First resin layer cylinder temperature: 190℃~210℃ Second resin layer cylinder temperature: 260℃~320℃ Mold temperature: 25℃~50℃

[0095] The translucent cover member is integrally formed by laminating a first resin layer and a second resin layer in the radial direction in the cross-sectional direction. Specifically, the translucent cover member is a multi-color molded body formed by multi-color molding using a resin material constituting the first resin layer and a resin material constituting the second resin layer.

[0096] (Judgment criteria) Based on the test results, the extrusion moldability was evaluated using a score of 1 to 3 according to the following criteria. 3: A clear two-layer structure can be formed in the thickness direction, and the thickness of each layer is almost uniform. 2: A clear two-layer structure can be formed in the thickness direction, but the thickness of each layer is uneven. 1: Extrusion molding is possible, but the two materials are mixed together and a two-layer structure cannot be formed. A score of 3 was judged to indicate good extrusion moldability.

[0097] [result] The results are shown in Tables 1 and 2. [Table 1] [Table 2]

[0098] The results shown in Tables 1 and 2 indicate that a resin composition containing (a) a polypropylene-based resin and (b) an ethylene methyl acrylate copolymer, and containing specific amounts of the (a) polypropylene-based resin and the (b) ethylene methyl acrylate copolymer when the total amount of the (a) polypropylene-based resin and the (b) ethylene methyl acrylate copolymer is 100 parts by mass, can form a resin layer that has excellent chemical resistance and can be adhered to a resin layer containing a polycarbonate resin.

[0099] Furthermore, a comparison of Examples 5 to 8 with Examples 9 and 10 showed that a resin composition containing a specific amount of (c) maleic acid-modified polypropylene resin as the (a) polypropylene-based resin in the resin composition has good extrusion moldability in addition to the above-mentioned effects. This shows that the translucent cover according to one embodiment of the present invention can be suitably produced by co-extrusion molding the resin composition for a translucent cover according to one embodiment of the present invention with a resin composition containing a PC resin. [Industrial Applicability]

[0100] The resin composition according to one aspect of the present invention can be suitably used as a resin composition for a light-transmitting cover.

Claims

1. A resin composition for forming a resin layer that constitutes a translucent cover by adhering to a resin layer containing a polycarbonate resin, The resin composition is (a) a polypropylene-based resin; (b) an ethylene methyl acrylate copolymer; and Contains When the total amount of the (a) polypropylene resin and the (b) ethylene methyl acrylate copolymer is 100 parts by mass, (a) 35 parts by mass or more and 65 parts by mass or less of a polypropylene-based resin, and (b) 35 parts by mass or more and 65 parts by mass or less of an ethylene methyl acrylate copolymer; A resin composition for a light-transmitting cover, comprising:

2. 2. The resin composition according to claim 1, wherein after forming a laminate in which a resin layer made of the resin composition and a resin layer containing the polycarbonate resin are bonded by a heat press bonding method, when an incision is made in the laminate, the resin layer containing the polycarbonate resin does not peel off from the resin layer made of the resin composition.

3. The resin composition according to claim 1, wherein the resin composition has a total light transmittance of 70% or more.

4. The resin composition according to claim 1, wherein the haze is 62% or less.

5. 2. The resin composition according to claim 1, wherein the critical strain measured by a chemical crack test method is 0.6% or more.

6. 2. The resin composition according to claim 1, wherein the melt mass flow rate (MFR) measured by JIS K 7210-1 method (230°C, 2.16 kg) is 6.0 g / 10 min or less.

7. The (a) polypropylene-based resin contains (c) maleic acid-modified polypropylene resin, With respect to a total of 100 parts by mass of the (a) polypropylene-based resin and the (b) ethylene methyl acrylate copolymer, The resin composition according to claim 1, comprising 2 parts by mass or more and 6 parts by mass or less of the maleic acid-modified polypropylene resin (c).

8. The resin composition according to claim 1 , further comprising an antioxidant containing a thioether compound.

9. A light-transmitting cover configured to cover the light source, The light-transmitting cover is formed by integrally stacking a plurality of resin layers in the light irradiation direction of the light source, The plurality of resin layers include a first resin layer formed from the resin composition according to any one of claims 1 to 8; a second resin layer containing a polycarbonate resin; A translucent cover characterized in that the first resin layer and the second resin layer are bonded together, and the first resin layer is positioned further outward from the light source than the second resin layer.

10. The light-transmitting cover according to claim 9, wherein a thickness (T1) of the first resin layer and a thickness (T2) of the second resin layer satisfy a relationship of T1<T2.

11. A lighting fixture comprising: the light-transmitting cover according to claim 10; a light source; and a fixture body in which the light source is installed.

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