structure

Abstract

To provide a structure where an electronic circuit is stored in an electronic circuit storage box which prevents cracking and reduction in strength of a box and is excellent in insulation characteristics.SOLUTION: A structure is a structure where an electronic circuit is stored in a box and the electronic circuit is sealed with an urethane-based sealing agent, in which the box is brought into contact with the urethane-based sealing agent, the box is formed from a resin composition containing (a) a crystalline thermoplastic resin and (b) a polyphenylene ether resin and contains a phase (A) containing the component (a) as a main component and a phase (B) containing the component (b) as a main component, in a contact part between the box and the urethane-based sealing agent, a phase volume ratio (A)S / (B)S of the phase (A) and the phase (B) in a range between 1 μm and 3 μm in a thickness direction from the box surface is represented by X, and a phase volume ratio (A)C / (B)C of the phase (A) and the phase (B) at the central part in a thickness direction of the box is represented by Y, 0.1≤X≤1 and Y≥X.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a structure. [Background technology]

[0002] Polyphenylene ether resins have excellent electrical insulation properties and good heat resistance, hydrolysis resistance, and flame retardancy, and are therefore used in home appliances, office equipment, automobile parts, etc. Furthermore, because polyphenylene ether resins have poor moldability when used alone, they are mainly used in combination with polystyrene, etc. Alloys of polystyrene and polyphenylene ether resins have traditionally been used as boxes for housing electronic circuits such as photovoltaic power generation modules (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2010 / 047122 [Patent Document 2] International Publication No. 2012 / 111628 Summary of the Invention [Problem to be solved by the invention]

[0004] When an alloy of polystyrene and polyphenylene ether resin is used as a box for housing an electronic circuit, a silicone-based sealant is generally used as the sealant. Silicon-based sealants are expensive, and there is a growing demand for cheaper sealants. However, when a urethane-based sealant is used as the sealant for the electronic circuit, problems such as cracking and a decrease in strength can occur in the box.

[0005] Therefore, the present invention aims to provide a structure in which an electronic circuit is stored in an electronic circuit storage box and the electronic circuit is sealed with a urethane-based sealant, in which the box is free from cracks and loss of strength and has excellent insulating properties. [Means for solving the problem]

[0006] As a result of extensive research to solve the above problems, the present inventors have found that by using a box made of a resin composition containing (a) a crystalline thermoplastic resin and (b) a polyphenylene ether resin, a structure can be obtained that is free from cracks and strength reduction even when an electronic circuit is sealed with a urethane-based sealant, and that has excellent insulating properties.

[0007] That is, the present invention is as follows. [1] A structure in which an electronic circuit is housed in a box, and at least a portion of the electronic circuit is sealed with a urethane-based sealant, the box and the urethane-based sealant are in contact with each other at least partially; the box is made of a resin composition containing (a) a crystalline thermoplastic resin and (b) a polyphenylene ether resin; The box contains an (A) phase containing the (a) component as a main component and a (B) phase containing the (b) component as a main component, the content ratio of the component (a) and the component (b) in the resin composition is 15 to 60 parts by mass of the component (a) and 40 to 85 parts by mass of the component (b) relative to 100 parts by mass in total of the components (a) and (b); the total mass ratio of the (a) component and the (b) component in 100% by mass of the resin composition is 65% by mass or more, At the contact portion between the box and the urethane-based sealant, the phase volume ratio (A) of the (A) phase to the (B) phase in the range of 1 μm to 3 μm from the surface of the box in the thickness direction is S / (B) S is X, and the phase volume ratio (A) of the (A) phase to the (B) phase at the center in the thickness direction of the box is C / (B) C When Y is set, 0.1≦X≦0.5 and Y≧X. and Y is less than 1. A structure characterized by: [2] The resin composition has a melting point of a melting peak measured by a differential scanning calorimeter of 150°C or more and 300°C or less, and a melting enthalpy of 15 J / g or more and 85 J / g or less, [1 ] The structure described. [3] The component (a) is polypropylene. [1] or [2] The structure described in [4] The resin composition further contains (c) a hydrogenated block copolymer. [3] The structure described in [5] The composition contains 1 to 20 parts by mass of the (c) component relative to 100 parts by mass of the total of the (a) component and the (b) component. [4] The structure described in [6] The resin composition further contains (d) a phosphorus-based flame retardant, [1] to [5] 2. The structure according to claim 1 , [7] The composition contains 5 to 45 parts by mass of the (d) component relative to 100 parts by mass of the total of the (a) component and the (b) component. [6] The structure described in [8] The component (d) contains a phosphate ester flame retardant. [6] or [7] The structure described in [9] [1] ~ The tracking voltage resistance measured on the surface of the box is 600V or more. [8] 2. The structure according to claim 1 , [ 10 ] [1] to [2], wherein the urethane sealant contains a phthalate ester. [9] 2. The structure according to claim 1 , [ 11 ] The urethane-based sealant contains an oxyalkylene compound having a methylene chain having 6 or more carbon atoms, [1] to [ 10

[0023] The structure according to any one of the preceding items. [ 12 ] The urethane-based sealant contains an oxyalkylene compound synthesized from castor oil. 11

[0023] The structure described in [ 13 ] Used in solar power generation modules,[1]~[ 12

[0023] The structure according to any one of the preceding items. [ 14 ] Solar power generation connector, [1]~[ 12

[0023] The structure according to any one of the preceding items. [ 15 ] [1]~[, a solar power generation junction box 12

[0023] The structure according to any one of the preceding items. [Effects of the Invention]

[0008] According to the present invention, in a structure in which an electronic circuit is stored in an electronic circuit storage box and the electronic circuit is sealed with a urethane-based sealant, the box is free from cracks and strength reduction, and a structure with excellent insulation properties is obtained. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of an example box. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist thereof.

[0011] [Structure] The structure of this embodiment is a structure in which an electronic circuit is housed in a box, and at least a portion of the electronic circuit is sealed with a urethane-based sealant, and the box and the urethane-based sealant are in contact with each other at least in part, and the box is made of a resin composition containing (a) a crystalline thermoplastic resin and (b) a polyphenylene ether resin, and the box includes an (A) phase mainly composed of the component (a) and a (B) phase mainly composed of the component (b), and at the contact portion between the box and the urethane-based sealant, a phase volume ratio (A) of the (A) phase to the (B) phase is 1 μm to 3 μm from the surface of the box in the thickness direction. S / (B) S is defined as X, and the phase volume ratio (A) of the (A) phase to the (B) phase at the center of the thickness direction of the box is C / (B) C When Y is set, 0.1≦X≦1 and Y≧X. In this specification, the (a) crystalline thermoplastic resin may be referred to as "component (a)," and the (b) polyphenylene ether resin may be referred to as "component (b)."

[0012] <Resin composition> ((a) Crystalline thermoplastic resin) The crystalline thermoplastic resin (a) used in this embodiment is not particularly limited, but examples thereof include polyethylene, polypropylene, polyoxymethylene, polyamide, polyethylene terephthalate, polybutylene terephthalate, syndioctatic polystyrene, etc. Among these, from the viewpoints of heat resistance and processability, polyethylene, polypropylene, polyamide 66, and polyamide 9T are preferred, and polypropylene is particularly preferred. The component (a) may be used alone or in combination of two or more.

[0013] -polypropylene- The polypropylene is not particularly limited, and examples thereof include unmodified polypropylene, modified polypropylene, and a mixture of both. One type of polypropylene may be used alone, or two or more types may be used in combination.

[0014] The weight average molecular weight (Mw) of the polypropylene is preferably 400,000 or more, more preferably 700,000 or more, and particularly preferably 750,000 or more, from the viewpoint of suppressing drawdown during combustion and improving the balance between fluidity and mechanical strength of the resin composition, and is preferably 1,500,000 or less, and more preferably 1,300,000 or less. The weight-average molecular weight (Mw) can be determined by a conventionally known method using gel permeation chromatography (hereinafter also referred to as "GPC"). Here, the mobile phase is not particularly limited, and for example, o-dichlorobenzene can be used, and the standard substance is not particularly limited, and for example, polystyrene can be used.

[0015] The polypropylene is not particularly limited, and examples thereof include homopolymers and / or copolymers having propylene as a repeating unit structure, and preferred are crystalline propylene homopolymers, crystalline propylene-ethylene block copolymers, and mixtures of crystalline propylene homopolymers and crystalline propylene-ethylene block copolymers. The crystalline propylene-ethylene block copolymer is not particularly limited, and examples thereof include those having a crystalline propylene homopolymer portion and a propylene-ethylene random copolymer portion.

[0016] From the viewpoint of suppressing drawdown during combustion and improving the balance between fluidity and mechanical strength of the resin composition, the melt flow rate (hereinafter also referred to as "MFR") of the polypropylene is preferably 0.1 g / 10 min or more, more preferably 0.3 g / 10 min or more, and is preferably 10 g / 10 min or less, more preferably 6 g / 10 min or less, and particularly preferably 3 g / 10 min or less. Specifically, MFR can be measured in accordance with ISO1133 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0017] The method for producing polypropylene is not particularly limited, and known methods can be used.

[0018] A specific example of a method for producing polypropylene is a method of polymerizing propylene in the presence of a polymerization catalyst composition containing a titanium trichloride catalyst, a titanium halide catalyst supported on a carrier such as magnesium chloride, or the like, and an alkylaluminum compound, at a temperature of 0 to 100°C and a pressure of 3 to 100 atmospheres. In the above method, a chain transfer agent such as hydrogen may be added to adjust the molecular weight of the polymer.

[0019] In the above method, in addition to the polymerization catalyst composition, the polymerization system may further contain an electron donor compound as an internal donor component or an external donor component to enhance the isotacticity of the resulting polypropylene and the polymerization activity of the polymerization system. These electron donor compounds are not particularly limited, and known compounds can be used. Specific examples of electron donor compounds include ester compounds such as ε-caprolactone, methyl methacrylate, ethyl benzoate, and methyl toluate; phosphites such as triphenyl phosphite and tributyl phosphite; phosphoric acid derivatives such as hexamethylphosphoric triamide; alkoxyester compounds; aromatic monocarboxylic acid esters; aromatic alkylalkoxysilanes; aliphatic hydrocarbon alkoxysilanes; various ether compounds; various alcohols; and various phenols.

[0020] The polymerization method in the above method may be either a batch method or a continuous method, and the polymerization method may be solution polymerization or slurry polymerization using a solvent such as butane, pentane, hexane, heptane, or octane, or may be bulk polymerization in a monomer or gas phase polymerization in a gaseous polymer without a solvent.

[0021] Among the methods for producing polypropylene, a method for producing a crystalline propylene-ethylene block copolymer is not particularly limited, and examples thereof include a method comprising: a first step of obtaining a crystalline propylene homopolymer portion; and a second step of copolymerizing the crystalline propylene homopolymer portion with ethylene and, if necessary, other α-olefins to obtain a propylene-ethylene block copolymer portion bonded to the crystalline propylene homopolymer portion. The other α-olefins are not particularly limited, and examples thereof include propylene, 1-butene, and 1-hexene.

[0022] The modified polypropylene is not particularly limited, and examples thereof include those obtained by grafting or adding an α,β-unsaturated carboxylic acid or a derivative thereof (e.g., an acid anhydride, an ester, etc.) to the above-mentioned polypropylene. The percentage of mass increase due to grafting or addition is not particularly limited, and is preferably 0.01% by mass or more, more preferably 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 5% by mass or less, relative to 100% by mass of the modified polypropylene.

[0023] The method for producing the modified polypropylene is not particularly limited, and examples thereof include a method of reacting the above-mentioned polypropylene with an α,β-unsaturated carboxylic acid or a derivative thereof in a molten state, a solution state, or a slurry state at 30 to 350°C in the presence or absence of a radical generator.

[0024] When the polypropylene is a mixture of unmodified polypropylene and modified polypropylene, the mixing ratio of the unmodified polypropylene and the modified polypropylene is not particularly limited and may be any ratio.

[0025] ((b) Polyphenylene ether resin) The (b) polyphenylene ether resin used in the present embodiment is not particularly limited, and examples thereof include polyphenylene ether, modified polyphenylene ether, and a mixture of both. The (b) polyphenylene ether resin may be used alone or in combination of two or more.

[0026] (b) From the viewpoint of further improving the flame retardancy of the resin composition, the reduced viscosity of the polyphenylene ether resin is preferably 0.25 dL / g or more, more preferably 0.28 dL / g or more, and is preferably 0.45 dL / g or less, more preferably 0.36 dL / g or less, and particularly preferably 0.35 dL / g or less. The reduced viscosity can be controlled by the polymerization time and the amount of catalyst. The reduced viscosity can be measured using a chloroform solution with ηsp / c of 0.5 g / dL at a temperature of 30°C, and specifically, can be measured by the method described in the examples below.

[0027] -Polyphenylene ether- The polyphenylene ether is not particularly limited, and examples thereof include a homopolymer having a repeating unit structure represented by the following formula (3) and / or a copolymer having a repeating unit structure represented by the following formula (3).

[0028] [ka] [In the formula, R 31 , R 32 , R 33 , and R 34 are each independently a monovalent group selected from the group consisting of a hydrogen atom, a halogen atom, a primary alkyl group having 1 to 7 carbon atoms, a secondary alkyl group having 1 to 7 carbon atoms, a phenyl group, a haloalkyl group, an aminoalkyl group, a hydrocarbyloxy group, and a halohydrocarbyloxy group in which at least two carbon atoms separate the halogen atom from the oxygen atom.

[0029] Such polyphenylene ether is not particularly limited, and known ones can be used. Specific examples of polyphenylene ether include homopolymers such as poly(2,6-dimethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), poly(2-methyl-6-phenyl-1,4-phenylene ether), and poly(2,6-dichloro-1,4-phenylene ether); and copolymers such as copolymers of 2,6-dimethylphenol with other phenols such as 2,3,6-trimethylphenol and 2-methyl-6-butylphenol; poly(2,6-dimethyl-1,4-phenylene ether) and copolymers of 2,6-dimethylphenol with 2,3,6-trimethylphenol are preferred, and poly(2,6-dimethyl-1,4-phenylene ether) is more preferred.

[0030] The method for producing polyphenylene ether is not particularly limited, and a conventionally known method can be used. Specific examples of the method for producing polyphenylene ether include the method described in U.S. Pat. No. 3,306,874, etc., which involves oxidatively polymerizing 2,6-xylenol using a complex of cuprous salt and amine as a catalyst, and the methods described in U.S. Pat. No. 3,306,875, U.S. Pat. No. 3,257,357, U.S. Pat. No. 3,257,358, JP-B-52-17880, JP-A-50-51197, JP-A-63-152628, etc.

[0031] -Modified polyphenylene ether- The modified polyphenylene ether is not particularly limited, and examples thereof include those obtained by grafting or adding a styrene polymer or a derivative thereof to the above-mentioned polyphenylene ether. The percentage of mass increase due to grafting or addition is not particularly limited, and is preferably 0.01% by mass or more, and more preferably 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 5% by mass or less, relative to 100% by mass of the modified polyphenylene ether.

[0032] The method for producing the modified polyphenylene ether is not particularly limited, and examples thereof include a method of reacting the polyphenylene ether with a styrene-based polymer or a derivative thereof in a molten state, a solution state, or a slurry state at 80 to 350°C in the presence or absence of a radical generator.

[0033] When the (b) polyphenylene ether resin used in this embodiment is a mixture of polyphenylene ether and modified polyphenylene ether, the mixing ratio of the polyphenylene ether and the modified polyphenylene ether is not particularly limited and may be any ratio.

[0034] ((c) Hydrogenated Block Copolymer) In this embodiment, when polyethylene, polypropylene, polyamide 66, polyamide 9T, or polypropylene is used as the (a) crystalline thermoplastic resin (preferably when polypropylene is used), the resin composition preferably contains (c) a hydrogenated block copolymer as a compatibilizer. Note that the (c) hydrogenated block copolymer does not contain the (a) component or the (b) component. The (c) hydrogenated block copolymer used in this embodiment is not particularly limited, and examples thereof include unmodified hydrogenated block copolymers, modified hydrogenated block copolymers, and mixtures of both. The (c) hydrogenated block copolymers may be used alone or in combination of two or more. The (c) hydrogenated block copolymer acts as a compatibilizer or impact resistance agent for the above polypropylene and the above (b) polyphenylene ether resin. The (c) hydrogenated block copolymer may be used alone or in combination of two or more.

[0035] (c) The hydrogenated block copolymer is a block copolymer obtained by hydrogenating at least a portion of a block copolymer comprising a polymer block A mainly composed of a vinyl aromatic compound and a polymer block B mainly composed of a conjugated diene compound. Here, the sum of the 1,2-vinyl bond content and the 3,4-vinyl bond content of the conjugated diene compound in polymer block B (hereinafter also referred to as the "total vinyl bond content") is 30 to 90%. The sum of the 1,2-vinyl bond content and the 3,4-vinyl bond content (total vinyl bond content) refers to the ratio of the sum of the 1,2-vinyl bond content and the 3,4-vinyl bond content to the sum of the 1,2-vinyl bond content, the 3,4-vinyl bond content, and the 1,4-conjugated bond content in polymer block B before hydrogenation. The total vinyl bond content can be measured using an infrared spectrophotometer and calculated according to the method described in Analytical Chemistry, Volume 21, No. 8, August 1949.

[0036] Matters relating to the unmodified and modified hydrogenated block copolymers will be described below.

[0037] -Polymer block A mainly composed of vinyl aromatic compounds- The polymer block A mainly composed of a vinyl aromatic compound is not particularly limited, and examples thereof include a homopolymer block of a vinyl aromatic compound, and a copolymer block of a vinyl aromatic compound and a conjugated diene compound. In addition, the phrase "mainly composed of a vinyl aromatic compound" in the polymer block A means that the content of the vinyl aromatic compound moiety in the polymer block A before hydrogenation is more than 50% by mass, and the content is preferably 70% by mass or more, more preferably 80% by mass or more, and may be 100% by mass or less.

[0038] The vinyl aromatic compound constituting the polymer block A is not particularly limited and examples thereof include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, diphenylethylene, etc., with styrene being preferred. The above vinyl aromatic compounds may be used alone or in combination of two or more.

[0039] From the viewpoint of improving the heat creep resistance of the resin composition, the number average molecular weight (Mn) of the polymer block A is preferably 15,000 or more, more preferably 20,000 or more, particularly preferably 25,000 or more, and is preferably 100,000 or less. The number average molecular weight (Mn) can be determined by a conventionally known method using GPC (mobile phase: chloroform, standard substance: polystyrene). Specifically, the number average molecular weight (Mn) can be measured by the method described in the examples below.

[0040] -Polymer block B mainly composed of conjugated diene compounds- The polymer block B mainly composed of a conjugated diene compound is not particularly limited, and examples thereof include a homopolymer block of a conjugated diene compound, and a copolymer block of a conjugated diene compound and a vinyl aromatic compound. In addition, the phrase "mainly composed of a conjugated diene compound" in the polymer block B means that the content of the conjugated diene compound portion in the polymer block B before hydrogenation exceeds 50% by mass. From the viewpoint of improving the fluidity of the resin composition, the content is preferably 70% by mass or more, more preferably 80% by mass or more, and may be 100% by mass or less.

[0041] The conjugated diene compound constituting the polymer block B is not particularly limited and examples thereof include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc., butadiene, isoprene, and combinations thereof are preferred, and butadiene is more preferred. The above conjugated diene compounds may be used alone or in combination of two or more.

[0042] Here, in the microstructure of polymer block B (bonding form of the conjugated diene compound), the sum of the 1,2-vinyl bond amount and the 3,4-vinyl bond amount (total vinyl bond amount) is 30% or more, preferably 45% or more, and more preferably 65% or more, and is 90% or less, from the viewpoint of improving the compatibility of polymer block B with component (a).

[0043] The method for synthesizing the block copolymer containing the polymer block A and the polymer block B is not particularly limited, and examples thereof include known methods such as anionic polymerization.

[0044] The block structure of the unmodified and modified hydrogenated block copolymers is not particularly limited, and examples of the component (c) include structures such as AB, ABA, BABA, (AB-)M, and ABABA, where "A" represents polymer block A and "B" represents polymer block B. Here, (AB-)M represents the reaction residue of a polyfunctional coupling agent such as silicon tetrachloride (M=Si) or tin tetrachloride (M=Sn), or the residue of an initiator such as a polyfunctional organolithium compound.

[0045] The molecular structure of the unmodified and modified hydrogenated block copolymers is not particularly limited, and examples thereof include linear, branched, radial, and combinations thereof.

[0046] The distribution of the vinyl aromatic compound in the molecular chain of polymer block A and the distribution of the conjugated diene compound in the molecular chain of polymer block B contained in the block copolymer are not particularly limited, and examples thereof include random, tapered (where the monomer portion increases or decreases along the molecular chain), partial block, and combinations thereof.

[0047] When a block copolymer contains a plurality of polymer blocks A or a plurality of polymer blocks B, the plurality of polymer blocks A or the plurality of polymer blocks B may have the same structure or different structures.

[0048] With respect to the entire block copolymer including polymer block A and polymer block B, from the viewpoints of improving the fluidity, impact resistance, and appearance of the hydrogenated block copolymer and reducing the occurrence of welds, the content of the vinyl aromatic compound in the block copolymer before hydrogenation is preferably 20% by mass or more, more preferably 30% by mass or more, and is preferably 95% by mass or less, more preferably 80% by mass or less. The content of the vinyl aromatic compound can be measured using an ultraviolet spectrophotometer.

[0049] The number average molecular weight (Mn) of the block copolymer before hydrogenation is preferably 5,000 or more, more preferably 10,000 or more, and particularly preferably 30,000 or more, and is preferably 1,000,000 or less, more preferably 800,000 or less, and particularly preferably 500,000 or less. The number average molecular weight can be determined by a conventionally known method using GPC (mobile phase: chloroform, standard substance: polystyrene).

[0050] The molecular weight distribution (Mw / Mn) of the block copolymer before hydrogenation is preferably 10 or less, more preferably 8 or less, and particularly preferably 5 or less. The molecular weight distribution (Mw / Mn) can be calculated by dividing the weight average molecular weight (Mw) determined by a conventional method using GPC (mobile phase: chloroform, standard substance: polystyrene) by the number average molecular weight (Mn) described above.

[0051] The method for hydrogenating the block copolymer is not particularly limited, and examples thereof include methods of hydrogenating using a homogeneous hydrogenation catalyst such as (1) a supported heterogeneous hydrogenation catalyst in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, or diatomaceous earth; (2) a so-called Ziegler-type hydrogenation catalyst in which a transition metal salt such as an organic acid salt or an acetylacetonate salt of Ni, Co, Fe, or Cr, etc., is used with a reducing agent such as an organoaluminum; or (3) a homogeneous hydrogenation catalyst such as a so-called organometallic complex of an organometallic compound such as Ti, Ru, Rh, or Zr, for example, under conditions of a reaction temperature of 0 to 200°C and a hydrogen pressure of 0.1 to 15 MPa.

[0052] The hydrogenation rate of the conjugated diene compound moiety constituting the polymer block B in the unmodified and modified hydrogenated block copolymers is not particularly limited, but from the viewpoint of improving heat resistance, it is preferably 50% or more, more preferably 80% or more, and particularly preferably 90% or more, based on the total amount of double bonds derived from the conjugated diene compound. The hydrogenation rate can be measured using a nuclear magnetic resonance (NMR) spectrometer.

[0053] The method for producing the unmodified and modified hydrogenated block copolymers is not particularly limited, and known production methods can be used. Specific examples of known production methods include those described in JP-A-47-11486, JP-A-49-66743, JP-A-50-75651, JP-A-54-126255, JP-A-56-10542, JP-A-56-62847, JP-A-56-100840, JP-A-2-300218, British Patent No. 1,130,770, U.S. Pat. No. 3,281,383, U.S. Pat. No. 3,639,517, British Patent No. 1,020,720, U.S. Pat. No. 3,333,024, and U.S. Pat. No. 4,501,857.

[0054] In the following, matters relating to the modified hydrogenated block copolymer will be particularly described.

[0055] -Modified hydrogenated block copolymer- The modified hydrogenated block copolymer is obtained by grafting or adding an α,β-unsaturated carboxylic acid or a derivative thereof (for example, an acid anhydride, an ester, etc.) to the above unmodified hydrogenated block copolymer.

[0056] The percentage of mass increase due to grafting or addition is not particularly limited, and is preferably 0.01% by mass or more, more preferably 10% by mass or less, more preferably 7% by mass or less, and particularly preferably 5% by mass or less, relative to 100% by mass of the unmodified hydrogenated block copolymer.

[0057] The method for producing the modified hydrogenated block copolymer is not particularly limited, and examples thereof include a method of reacting the unmodified hydrogenated block copolymer with an α,β-unsaturated carboxylic acid or a derivative thereof in the presence or absence of a radical generator, in a molten state, a solution state, or a slurry state, at a temperature of 80 to 350°C.

[0058] ((d) Phosphorus-based flame retardants) In this embodiment, a phosphorus-based flame retardant is preferably contained in the resin composition because it can impart flame retardancy. The phosphorus-based flame retardant is not particularly limited, but examples thereof include phosphate ester-based flame retardants, condensed phosphates or derivatives thereof, organic phosphinates or derivatives thereof, phosphazenes or derivatives thereof, and mixtures thereof. From the viewpoint of maintaining flame retardancy over a long period of time, phosphate ester-based flame retardants are preferred. (d) The phosphorus-based flame retardants may be used alone or in combination of two or more.

[0059] -Phosphate ester flame retardant- The phosphate ester-based flame retardant optionally used in this embodiment is not particularly limited, and may be any phosphate ester compound (phosphate ester compound, condensed phosphate ester compound, etc.) that has the effect of improving the flame retardancy of the resin composition, such as triphenyl phosphate, phenyl bis dodecyl phosphate, phenyl bis neopentyl phosphate, phenyl-bis(3,5,5'-trimethyl-hexyl phosphate), ethyl diphenyl phosphate, 2-ethyl-hexyl di(p-tolyl) phosphate, bis-(2-ethylhexyl)-p-tolyl phosphate, tritolyl phosphate, bis-(2-ethylhexyl)phenyl phosphate, tri-(nonylphenyl) phosphate, phosphate, di(dodecyl)-p-tolyl phosphate, tricresyl phosphate, dibutyl phenyl phosphate, 2-chloroethyl diphenyl phosphate, p-tolyl bis(2,5,5'-trimethylhexyl) phosphate, 2-ethylhexyl diphenyl phosphate, bisphenol A bis(diphenyl phosphate), diphenyl-(3-hydroxyphenyl) phosphate, bisphenol A bis(dicresyl phosphate), resorcinol bis(diphenyl phosphate), resorcinol bis(dixylenyl phosphate), 2-naphthyl diphenyl phosphate, 1-naphthyl diphenyl phosphate, di(2-naphthyl)phenyl phosphate, and the like.

[0060] In particular, the phosphate ester compounds include: The following formula (4) [ka] [In the formula, Q 41 , Q 42 , Q 43 , Q 44 are each independently an alkyl group having 1 to 6 carbon atoms; R 41 , R 42 are each independently a methyl group; R 43 , R 44 are each independently a hydrogen atom or a methyl group; x is an integer of 0 or greater; p1, p2, p3, and p4 are each an integer of 0 to 3; and q1 and q2 are each an integer of 0 to 2. or The following formula (5) [ka] [In the formula, Q 51 , Q 52 , Q 53 , Q 54 are each independently an alkyl group having 1 to 6 carbon atoms; R 51 is a methyl group; y is an integer of 0 or greater; r1, r2, r3, and r4 are each an integer of 0 to 3; and s1 is each an integer of 0 to 2. The aromatic condensed phosphate ester compound represented by the following formula (I) is preferably used as a main component. The aromatic condensed phosphate ester compounds represented by the above formula (4) and formula (5) may each contain multiple types of molecules, and it is preferable that x and y in each molecule are integers of 1 to 3.

[0061] In a suitable phosphate ester compound containing as a main component at least one compound selected from the group consisting of condensed phosphate ester compounds represented by the above formula (4) and the above formula (5), it is preferred that the average value of x or y as a whole is at least 1. The above suitable phosphate ester compound is generally available as a mixture containing at least 90% of compounds in which x or y is 1 to 3, and contains, in addition to the compounds in which x or y is 1 to 3, polymers in which x or y is 4 or more and other by-products.

[0062] The resin composition may contain components other than the component (a), the component (b), the hydrogenated block copolymer (c), and the phosphorus-based flame retardant (d) within a range that does not impair the effects of the present invention.

[0063] (characteristic) The shape of the box of this embodiment is not particularly limited, but examples thereof include a cube, a rectangular parallelepiped, a polygonal pyramid, a polygonal prism, a cone, a cylinder, and a sphere. The wall of the box may have the same thickness on all sides, or may have different thicknesses. The wall of the box of this embodiment preferably has a thickness of 0.5 mm or more, more preferably 1 to 5 mm. The box of this embodiment is in contact with at least a portion of the urethane sealant. Preferably, at least a portion of the inner surface of the box is in contact with the urethane sealant.

[0064] -Morphology of the Box- The box of this embodiment includes an (A) phase mainly composed of the component (a) and a (B) phase mainly composed of the component (b). The (B) phase may include components (c) and (d) in addition to the component (b). The box of this embodiment may consist of only the (A) and (B) phases, or may include other phases (for example, phases not mainly composed of the components (a) and (b)). The "main component" in the (A) phase and the (B) phase refers to a component that accounts for more than 50% by mass, preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, relative to 100% by mass of the unit mass of each phase. At the contact portion between the box and the urethane-based sealant, the volume ratio (phase volume ratio) (A) of the (A) phase to the (B) phase in the range of 1 μm to 3 μm from the surface of the box in the thickness direction S / (B) S where X is the volume ratio of the (A) phase to the (B) phase at the center of the box in the thickness direction (phase volume ratio) (A) C / (B) C When Y is defined as Y≧X. When the phase volume ratio is in this range, the resistance to the urethane sealant tends to be excellent. The above X and Y can be measured by the method described in the examples below. Furthermore, from the viewpoint of better chemical resistance, it is preferable that Y>X, more preferably Y>1.1X, even more preferably Y>1.2X, and even more preferably Y>1.3X. X is preferably less than 1, more preferably 0.1≦X≦0.5, and even more preferably 0.15≦X≦0.4. Y is also preferably less than 1. When there are multiple contact points between the box and the urethane-based sealant, it is preferable that at least one contact point satisfies the above range, it is more preferable that all contact points satisfies the above range, and it is even more preferable that the entire inner surface of the box where the box and the urethane-based sealant come into contact satisfies the above range. The center refers to the range of ±5% of the 100% thickness of the box from the center of the thickness direction of the box in the direction perpendicular to the contact part, which is part of the inner surface of the box. Methods for obtaining a box that satisfies the above-mentioned morphology include a method for adjusting the mass ratio of (a) crystalline thermoplastic resin and (b) polyphenylene ether resin in the resin composition, and a method for adjusting molding conditions such as molding temperature and average flow velocity when injection molding the resin composition produced in the melt-kneading process.

[0065] By reducing the mass proportion of the (a) crystalline thermoplastic resin in the resin composition, X tends to decrease. Furthermore, if the mass proportion of the (a) crystalline thermoplastic resin is too high or too low, the ratio of Y to X tends to decrease. From the viewpoint of a desirable phase volume ratio, the mass ratio of the (a) crystalline thermoplastic resin to the (b) polyphenylene ether resin, (a) component / (b) component, is preferably 15 / 85 to 60 / 40, more preferably 20 / 80 to 50 / 50, and even more preferably 25 / 75 to 45 / 55. Furthermore, the total mass ratio of the (a) component and the (b) component in 100% by mass of the resin composition is preferably 60% by mass or more, more preferably 65% by mass or more, and particularly preferably 70% by mass or more.

[0066] The box can be formed by molding the resin composition, for example, by injection molding, compression molding, etc., with injection molding being preferred. In injection molding, the molding temperature is preferably 20°C to 50°C higher than the melting point of the (a) crystalline thermoplastic resin. While there are no particular limitations on the injection molding conditions, it is preferable that the average flow velocity of the molten resin in the molded product be 5 to 100 mm / sec, from the viewpoint of a desirable phase volume ratio. The average flow velocity is more preferably 5 to 50 mm / sec, and even more preferably 5 to 30 mm / sec. By reducing the average flow velocity, it tends to be possible to increase the ratio of Y to X. The average flow rate can be calculated from the time required for filling and the volume of the molded product.

[0067] -Heat resistance- The resin composition preferably has a melting point of a melting peak measured by a differential scanning calorimeter of 150°C to 300°C and a melting enthalpy of 15 J / g to 85 J / g, more preferably a melting point of 155°C to 275°C and a melting enthalpy of 17 J / g to 80 J / g, and even more preferably a melting point of 160°C to 270°C and a melting enthalpy of 20 J / g to 70 J / g. The melting point and melting enthalpy of the melting peak can be measured by the method described in the Examples below.

[0068] - Tracking resistance - The tracking resistance voltage measured on the surface of the molded box is preferably 600 V or more. The tracking voltage resistance can be measured by the method described in the examples below.

[0069] -composition- In the resin composition, the mass proportions of the components (a) and (b) are preferably 1 to 60 parts by mass of the component (a) and 40 to 99 parts by mass of the component (b) relative to 100 parts by mass of the total of the components (a) and (b), from the viewpoint of chemical resistance and insulating performance, and more preferably 16 to 58 parts by mass of the component (a) and 42 to 84 parts by mass of the component (b). The mass ratio of component (a) to 100 parts by mass of the resin composition is preferably 10 to 50 parts by mass, more preferably 15 to 40 parts by mass, from the viewpoints of chemical resistance and insulating performance. The mass ratio of component (b) to 100 parts by mass of the resin composition is preferably 20 to 65 parts by mass, more preferably 25 to 60 parts by mass, from the viewpoints of chemical resistance and insulating performance. When component (a) is polypropylene, from the viewpoint of impact resistance, it is preferable that the component (c) contains 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and even more preferably 5 to 13 parts by mass of hydrogenated block copolymer per 100 parts by mass of the total of components (a) and (b). When (d) a phosphorus-based flame retardant is further contained, from the viewpoint of flame retardancy, the phosphorus-based flame retardant is preferably contained in an amount of 5 to 45 parts by mass, more preferably 10 to 44 parts by mass, and even more preferably 20 to 43 parts by mass, per 100 parts by mass of the total of components (a) and (b). The composition of the resin composition may be analyzed using a sample cut out from the contact portion in the thickness direction from the surface of the box to the entire thickness.

[0070] <Electronic circuit> Examples of the electronic circuits include electronic circuits stored in a junction box for connecting a cable from a photovoltaic power generation module that converts solar light energy into electricity, such as a DC switch, a backflow prevention diode, a fuse, an output terminal block, and a surge absorber. Preferably, at least a portion of the electronic circuit is housed inside the box, and more preferably, the entire organ electronic circuit is housed inside the box.

[0071] <Urethane sealant> In this embodiment, the urethane-based sealant is a sealant containing an isocyanate compound and a polyol compound as main components. From the viewpoint of processability, the urethane sealant preferably contains a phthalate ester. From the viewpoint of water vapor permeation resistance, the urethane sealant preferably contains an oxyalkylene compound having a methylene chain with six or more carbon atoms. From the viewpoint of water vapor permeation resistance, the urethane sealant preferably contains an oxyalkylene compound synthesized from castor oil.

[0072] According to the structure of this embodiment, by controlling the phase volume ratio near the wall surface of the box and the phase volume ratio at the center of the wall of the box at the contact portion between the urethane sealant and the box within a specific range, cracking of the box can be prevented and a decrease in the strength of the box can be suppressed. Therefore, the structure of this embodiment is preferably used in, for example, a photovoltaic power generation module, and more preferably is a component within the photovoltaic power generation module. Furthermore, the structure of this embodiment is preferably a photovoltaic power generation connector or a photovoltaic power generation junction box. [Example]

[0073] The present embodiment will be described below with reference to examples, but the present embodiment is not limited to these examples. The raw materials used are as follows.

[0074] (a) Crystalline thermoplastic resin (a-1) Polypropylene Novatec EA9FT manufactured by Japan Polypropylene Corporation was used. (a-2) Polyethylene Suntech J320 manufactured by Asahi Kasei Chemicals was used. (a-3) Polyamide 66 (PA66) We used Leona 1400S manufactured by Asahi Kasei Chemicals. (a-4) Polyamide 9T (PA9T) Referring to the method described in the examples of JP 2000-204239 A, 3256.2 g (19.6 mol) of terephthalic acid, 2690.9 g (17.0 mol) of 1,9-nonanediamine, 474.9 g (3.0 mol) of 2-methyl-1,8-octanediamine, 97.7 g (0.8 mol) of benzoic acid, 6.5 g of sodium hypophosphite monohydrate (0.1% by mass relative to the total of the four polyamide raw materials), and 6 L of distilled water were placed in a 20 L autoclave, and the inside atmosphere was replaced with nitrogen. After stirring at 100°C for 30 minutes, the inside temperature was raised to 310°C over 2 hours. At this time, the autoclave was pressurized at 22 kg / cm. 2 After maintaining this state for 1 hour, the temperature was raised to 330°C, and then the temperature was maintained at 330°C for 2 hours, while the steam was gradually released and the pressure was reduced to 22 kg / cm. 2 The reaction was carried out while maintaining the pressure at 10 kg / cm for 30 minutes. 2 The temperature was lowered to 0°C and the reaction was continued for another hour, yielding a prepolymer with an intrinsic viscosity [η] of 0.30 dL / g. This prepolymer was dried at 100°C under reduced pressure for 12 hours and pulverized to a size of 2 mm or less. This was subjected to solid-state polymerization at 230°C and 0.1 mmHg for 10 hours to yield a polyamide granular polymer. The resulting granular polymer was pelletized using a twin-screw extruder set at a cylinder temperature of 330°C, and this was designated (a-4).

[0075] (b) Polyphenylene ether resin (b-1) Polyphenylene ether obtained by oxidative polymerization of 2,6-xylenol, with a reduced viscosity ηsp / c of 0.41 dL / g The reduced viscosity was measured using an Ubbelohde viscometer in a 0.5 g / dL chloroform solution at 30°C.

[0076] (c) Hydrogenated block copolymer (c-1) A hydrogenated block copolymer was synthesized that had a hydrogenated polybutadiene-polystyrene-hydrogenated polybutadiene-polystyrene structure (BABA), with a bound styrene content of 44%, a number average molecular weight of the entire polymer of 95,000, a molecular weight distribution of 1.06, a number average molecular weight of the polystyrene block of 20,900, a total amount of 1,2-vinyl bonds and 3,4-vinyl bonds in the polybutadiene before hydrogenation of 75%, and a hydrogenation rate of the polybutadiene block of 99.9%. The total vinyl bond content of the polybutadiene block was measured using an infrared spectrophotometer, and the calculation method was performed in accordance with the method described in Analytical Chemistry, Volume 21, No. 8, August 1949. The amount of bound styrene was measured using an ultraviolet spectrophotometer. Furthermore, the number average molecular weight and molecular weight distribution of the entire polymer and the number average molecular weight of the polystyrene block were measured using GPC (mobile phase: chloroform, standard substance: polystyrene). Furthermore, the hydrogenation rate of the polybutadiene block was measured using NMR.

[0077] (d) Phosphorus-based flame retardants (d-1) Phosphinates (Clariant Exolit OP1312) (d-2) Condensed phosphate ester compound E890 manufactured by Daihachi Chemical Co., Ltd.

[0078] (e) Other ingredients HIPS: (Product name "CT-60", manufactured by Petrochemicals Co., Ltd.)

[0079] [Production Examples 1 to 10] A twin-screw extruder ZSK-25 (manufactured by Coperion, number of barrels: 12) was used as the resin composition production device. The twin-screw extruder had a first raw material supply port (first barrel) on the upstream side of the raw material flow direction, a second (sixth barrel) and a third raw material supply port (eighth barrel) downstream of this, and a liquid addition pump further downstream. Vacuum vents were provided between the first raw material supply port and the second raw material supply port, and between the third raw material supply port and the liquid addition pump. The extruder screw had three kneading blocks. The first kneading block was located in the fourth barrel of the extruder and consisted of, from the upstream side, one R-KD (feed type: R-type kneading disc) with L (the length in the screw axial direction of the screw constituting the kneading block) of 12 mm, one N-KD (non-conveying type: N-type kneading disc) with L of 24 mm, and one L-KD (reverse feed: L-type kneading disc) with L of 12 mm. The second kneading block was located at the seventh barrel of the extruder and consisted of, from the upstream side, one R-KD with an L of 12 mm, one L-KD with an L of 12 mm, and one R-KD with an L of 12 mm. The third kneading block was located at the ninth barrel of the extruder and consisted of, from the upstream side, one R-KD with an L of 12 mm and one L-KD with an L of 12 mm. The term "kneading block" refers to a block consisting of multiple continuous screw elements known as kneading disks, which have a high kneading effect. Furthermore, the raw materials were supplied to the second and third supply ports using a forced side feeder from the side opening of the extruder. The components (a) to (d) were fed into the twin-screw extruder configured as described above in the composition shown in Table 1 and melt-kneaded at a screw rotation speed of 300 rpm and a discharge rate of 15 kg / hour to obtain pellets of the resin composition of Production Example 1. The extrusion temperature was 270°C when polypropylene and polyethylene were used, 300°C when polyamide 66 was used, and 330°C when polyamide 9T was used. According to the blending ratios in Table 1, pellets of the resin compositions of Production Examples 1 to 10 were obtained.

[0080] [Examples 1 to 11, Comparative Examples 1 to 3] Using the pellets obtained in Production Examples 1 to 10, box-shaped molded articles (120 mm × 80 mm × 50 mm, wall thickness 2 mm) having the shape shown in FIG. 1 were produced by injection molding. The injection molding was performed using an injection molding machine (Toshiba Corporation, EC100) with a mold temperature of 70°C, injection time of 15 seconds, and cooling time of 10 seconds. The average flow velocity was 25 mm / sec as shown in Table 1, but was changed to 10 mm / sec, 45 mm / sec, and 100 mm / sec in Examples 1, 3, and 4, respectively, and 200 mm / sec in Comparative Example 1. The cylinder temperature was 270°C when (a-1) polypropylene and (a-2) polyethylene were used, 300°C when (a-3) polyamide 66 was used, and 330°C when (a-4) polyamide 9T was used. Also, a 4 mm thick ISO test piece was obtained by the same injection molding under the injection molding conditions of 15 seconds for injection and 10 seconds for cooling. The box-shaped molded products and ISO test pieces were subjected to the following evaluations. The evaluation results are shown in the evaluation column of Table 1.

[0081] [Melting temperature, enthalpy of fusion] A PerkinElmer Diamond DSC differential scanning calorimeter was used. The temperature was increased and decreased at a rate of ±20°C / min. Approximately 10 mg of a sample cut from the box-shaped molded product was heated from 50°C and held at 350°C for 3 minutes. The sample was then cooled to 50°C and heated again to observe the melting peak. The temperature at the top of the peak was taken as the melting temperature (i.e., the melting point of the melting peak). The heat of fusion (enthalpy of fusion) was determined from the area of the peak according to JIS K7122.

[0082] [Phase volume ratio] A urethane sealant (UF-820A / B, manufactured by Sanyu Rec Co., Ltd.) was applied to the box-shaped molded product and cured at 60°C for 1 hour. After 24 hours, the contact area was cut in the thickness direction of the box using an ultramicrotome to prepare thin film sections approximately 80 nm thick, including the surface of the molded product. The thin film sections were observed using a transmission electron microscope (SEM) at 2,500x magnification. The observed images were analyzed using image analysis software (product name LUSEX SE, manufactured by Nireco Corporation). A straight line connects the surface of the molded product that was in contact with the urethane sealant on both the left and right sides of the image, and this is designated line A. A line parallel to line A and shifted 1 μm in the thickness direction from the surface toward the interior of the molded product is designated line B, and a line shifted 3 μm toward the interior of the molded product is designated line C. (a) The dispersed phase primarily composed of crystalline thermoplastic resin, and (b) the black continuous phase primarily composed of PPE, both observed between lines B and C, are designated phase (A), and phase (B), respectively. The area ratio of phase (A) to phase (B) is designated the phase volume ratio (X) near the surface of the molded product. Similarly, a box-shaped molded product was cut using an ultramicrotome from the same contact point as above in the thickness direction of the box to prepare a thin film slice approximately 80 nm thick that included the center of the molded product, and this was analyzed using the same equipment. After adjusting the center of the molded product to be at the center of the observation field, within a range of 1 μm above and below the center, (a) the dispersed phase mainly composed of crystalline thermoplastic resin was defined as phase (A), and the black continuous phase mainly composed of PPE was defined as phase (B). The area ratio of phase (A) to phase (B) was defined as the phase volume ratio (Y) of the core part of the molded product.

[0083] [Tracking resistance] A tracking resistance test was conducted in accordance with UL 746A (ASTM D3638) using a tracking resistance tester, Model HAT-500-3, manufactured by Hitachi Chemical Co., Ltd. Test pieces measuring 65 mm wide x 90 mm long were cut out from the box-shaped molded product, and the tracking resistance test was conducted as follows. The test piece was placed in a HAT-500-3 device, and a voltage of 100 to 600 V was applied in 25 V increments between two electrodes in contact with the surface of the test piece. A 0.1% aqueous solution of ammonium chloride was dripped between the electrodes every 30 seconds. The number of drips of the aqueous solution of ammonium chloride was then measured until a current of 0.1 A or more was passed through the test piece for 0.5 seconds or more (dielectric breakdown). The tracking resistance test was carried out five times, and the voltage (V) was measured at which the average number of drops of the ammonium chloride aqueous solution became less than 50. The tracking resistance was evaluated based on the obtained voltage.

[0084] [Resistant to urethane sealants] A 10mm wide x 50mm long test piece cut from a box-shaped molded product was attached to a bending bar, and while strain corresponding to the curvature of the bending bar was applied, a urethane sealant (UF-820A / B, manufactured by Sanyu Rec Co., Ltd.) was applied to the surface of the test piece and cured at 60°C for 1 hour. After 48 hours, the occurrence of cracks on the surface of the test piece was observed, and the minimum strain at which cracks occurred was evaluated as the critical strain value.

[0085] [Strength retention after application of urethane sealant] A urethane sealant (UF-820A / B manufactured by Sanyu Rec Co., Ltd.) was applied to the bottom surface of the obtained box-shaped molded product and cured at 60°C for 1 hour. After leaving it for 48 hours, it was dropped freely from a height of 1 m onto a concrete surface, and those that had no cracks on the inside of the bottom surface were rated as ◯ (good), and those that had cracks were rated × (bad).

[0086] [Tensile strength, tensile elongation] Using the obtained ISO test pieces, the tensile strength (MPa) and tensile elongation (%) were measured in accordance with ISO527-1.

[0087] [Impact properties] Using the obtained ISO test specimen, the Charpy impact strength (notched, unit kJ / m) was measured in accordance with ISO179-1. 2 ) was measured.

[0088]

Table 1

Claims

1. A structure in which an electronic circuit is housed in a box, and at least a portion of the electronic circuit is sealed with a urethane-based sealant, the box and the urethane-based sealant are in contact with each other at least partially; the box is made of a resin composition containing (a) a crystalline thermoplastic resin and (b) a polyphenylene ether resin; The box includes an (A) phase containing the (a) component as a main component, and a (B) phase containing the (b) component as a main component, the resin composition contains the component (a) in an amount of 15 to 60 parts by mass and the component (b) in an amount of 40 to 85 parts by mass, relative to 100 parts by mass of the total of the component (a) and the component (b); the total mass ratio of the (a) component and the (b) component in 100% by mass of the resin composition is 65% by mass or more, At the contact portion between the box and the urethane-based sealant, the phase volume ratio (A) of the (A) phase to the (B) phase in the range of 1 μm to 3 μm from the surface of the box in the thickness direction is Ｓ / (B) Ｓ is X, and the phase volume ratio (A) of the (A) phase to the (B) phase at the center of the thickness direction of the box is Ｃ / (B) Ｃ where Y is the number of the saturation points, 0.1≦X≦0.5 and Y≧X; Y is less than 1; A structure characterized by:

2. The structure according to claim 1, wherein the resin composition has a melting point of a melting peak measured by a differential scanning calorimeter of 150°C or more and 300°C or less, and a melting enthalpy of 15 J / g or more and 85 J / g or less.

3. 3. The structure according to claim 1, wherein the component (a) is polypropylene.

4. The structure according to claim 3 , wherein the resin composition further contains (c) a hydrogenated block copolymer.

5. 5. The structure according to claim 4, wherein the component (c) is contained in an amount of 1 to 20 parts by mass per 100 parts by mass of the total of the components (a) and (b).

6. The structure according to any one of claims 1 to 5, wherein the resin composition further contains (d) a phosphorus-based flame retardant.

7. 7. The structure according to claim 6, wherein the component (d) is contained in an amount of 5 to 45 parts by mass per 100 parts by mass of the total of the components (a) and (b).

8. The structure according to claim 6 or 7, wherein the component (d) comprises a phosphate ester flame retardant.

9. 9. The structure according to claim 1, wherein the box has a tracking voltage resistance of 600 V or more measured on the surface thereof.

10. The structure according to any one of claims 1 to 9, wherein the urethane-based sealant contains a phthalic acid ester.

11. The structure according to any one of claims 1 to 10, wherein the urethane-based sealant contains an oxyalkylene compound having a methylene chain having 6 or more carbon atoms.

12. The structure of claim 11 , wherein the urethane-based sealant comprises an oxyalkylene compound synthesized from castor oil.

13. The structure according to any one of claims 1 to 12, for use in a photovoltaic module.

14. The structure of any one of claims 1 to 12, which is a photovoltaic connector.

15. The structure according to any one of claims 1 to 12, which is a junction box for photovoltaic power generation.

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