Abstract: A nonlimiting example method for synthesizing a pigment-pendent polyamide (PP-polyamide) may comprise: functionalizing metal oxide particles bound to a pigment particle with a compound having an epoxy to produce a surface treated pigment having a pendent epoxy; and reacting the pendent epoxy with a polyamide to yield the PP-polyamide. Another nonlimiting example method for synthesizing a PP-polyamide may comprise: functionalizing metal oxide particles bound to a pigment particle with a silica particle having a carboxylic acid surface treatment to produce a surface treated pigment having a pendent carboxylic acid; converting the pendent carboxylic acid to a pendent acid chloride; and reacting the pendent acid chloride with a polyamide to yield the PP-polyamide.

Abstract: A multiple component anhydride-free, thermosetting epoxy resin composition comprising, (A) at least one epoxy resin, and (B) at least one curing agent selected from the group of (b1) a polyetheramine of the formula (1) (Formula (1)), wherein x is a number of from 2 to 8, and (b2) a polyetheramine with at least one terminal end group of the formula (2) (Formula (2)), and (C) at least one epoxy silane, is, in particular, suitable for the manufacture of instrument transformers and dry-type transformers by casting, potting and encapsulation processes, wherein said articles exhibit good mechanical, electrical and dielectrical properties.

Abstract: Described herein are polymer compositions including (i) a polymer blend containing an amorphous polyester copolymer and a semi-crystalline polyamide polymer (“polyester/polyamide blend”), (ii) 1 weight percent (wt. %) to 5 wt. % of an epoxy functionalized impact modifier and optionally (iii) one or more additives. It was surprisingly found that incorporation of a specific amount of an epoxy functionalized impact modifier into polymer compositions including a polyester/polyamide blend provided for significantly improved impact performance, relative to corresponding polymer compositions incorporating non-epoxy functionalized impact modifiers or corresponding polymer compositions free of impact modifiers. Due at least in part to the significantly improved impact performance and outstanding chemical resistance, the polymer compositions described herein can be incorporated in a wide variety of application settings, including but not limited to mobile electronic application settings.

Abstract: A polyimide that is a reaction product of a diamine represented by Chemical Formula 1, a diamine represented by Chemical Formula 2, and a tetracarboxylic dianhydride represented by Chemical Formula 3: wherein, in Chemical Formulae 1 to 3, L1, L2, Ra to Rf, m, R2, R10, R12, R13, n7, and n8 are the same as defined in the specification.

Abstract: This invention provides a polymer thick film dielectric paste composition, comprising a mixture of titanium dioxide and boron nitride powders, a resin blend of polyol and phenoxy resin, one or more additives selected from the group consisting of a linear aliphatic polyester, a block copolymer, a blocked aliphatic polyisocyanate, and a wetting and dispersing agent, and one or more polar, aprotic solvents. The paste composition may be used to form polymer thick film dielectric layers in electrical circuits subject to thermoforming and in articles requiring stretchable dielectric layers such as wearables.

Abstract: Example methods and articles of manufacture related to electrospun aramid nanofibers are provided. One example method may include forming a resultant solution by reacting a solution of aramids dissolved in a solvent with an electrophile. In this regard, the electrophile may perform a side chain substitution on the dissolved aramids. The example method may further include electrospinning the resultant solution to form an aramid nanofiber.

Abstract: The object of the present invention is to provide a tire which is excellent in steering stabilities at low temperature and at high temperature after aging without deterioration of the initial steering stabilities at low temperature and at high temperature. The present invention relates to a tire having a tread composed of a rubber composition comprising a softener comprising 5 to 50 parts by mass of an adhesive resin and 5 to 50 parts by mass of a xylene-based low-temperature plasticizer based on 100 parts by mass of a rubber component.

Abstract: A composition including an amidoamine curing agent composition or a polyamide curing agent composition are disclosed. The composition includes the reaction products of (1) an amine component including at least one multifunctional amine of structure (I): wherein each R is independently H or CH2CH2CH2NH2; R1 is H, CH3CH2CH2N—, C1-C21 alkyl, or C1-C21 alkenyl; n is 2; and m is 1 or 2, with (2) a fatty acid or ester component selected from the group consisting of a dimer fatty acid or ester component, a monofunctional fatty acid or ester component, and combinations thereof. The amidoamine curing agent composition remains as liquid at ambient temperature.

Abstract: A resin composition comprising one or more cyanate compounds (A) selected from a group consisting of a naphthol aralkyl-based cyanate compound, a naphthylene ether-based cyanate compound, a xylene resin-based cyanate compound, a trisphenolmethane-based cyanate compound, and an adamantane skeleton-based cyanate compound; a polymaleimide compound (B) represented by general formula (1); and a filler (C).

Abstract: The invention relates to a monofunctional or multifunctional acrylated or methacrylated urethane oligomer where said urethane bond is obtained without use of isocyanate and by the carbonate-amine reaction between a cyclic carbonate and a monoamine or polyamine, with subsequently the conversion of the hydroxyls in the ? position with respect to the urethane bond into ester-acids by reaction with a cyclic anhydride, which reaction is followed by the conversion of said acid functional groups into acrylated or methacrylated end groups by reaction with a polyepoxide compound in the presence of acrylic or methacrylic acid. The invention also relates to a preparation process. Said oligomer is used as crosslinkable binder for a functionality of at least 2 in coating, molding, leaktightness agent or sealing compositions or, if monofunctional, as macromonomer in polymerizable compositions for the production of grafted polymers.

Abstract: The present invention concerns the use of a compound having the following formula (I), for the preparation of a polymer. The present invention also concerns the polymers obtained from polymerization of compound of formula (I), and their processes of preparation.

Abstract: A method for making a composite structure with a surfacing film thereon. The surfacing film is co-cured with fiber-reinforced resin composite materials. The surfacing film is formed from a curable resin composition containing an epoxy novolac resin, a tri-functional or tetra-functional epoxy resin, ceramic microspheres, an amine-based curing agent, particulate inorganic fillers; and a toughening component. The surfacing film exhibits high Tg and high cross-linked density after curing, as well as high resistance to paint stripper solutions.

Abstract: The present invention relates to a method for impregnating a filter having pores suitable for retaining particles within them that may be present in a flow of air suitable for passing through the filter, according to which the filter made up of a polymer membrane is impregnated with one or more organometallic salts by applying a treatment using supercritical CO2, the metal M of each salt being chosen from among the group of rare earths, yttrium, scandium, chromium, or a combination thereof. The invention also relates to the obtained filter and an associated method for the collection and quantitative analysis of nanoparticles.

Abstract: The invention discloses safety toe caps made from nano composite material and a preparation method of the nano composite safety toe cap. The toe caps are made from multi-layers of laminated glass fiber cloth coated with resin paste, wherein the percentage ratio of the resin paste to the glass fiber cloth is as follows: the resin paste accounts for 30-45%, the glass fiber cloth accounts for 55-70%, and the total sum is 100%; the resin paste comprises the following components in percentage by mass: 30-50% of thermosetting resin, 0.1-5% of modified carbon nanotubes, 10-30% of modified nitrile rubber, 5-25% of polyurethaneacrylate, 1-5% of prepolymerized silane oligomer, 0.5-2% of a high-temperature initiator such as tert-Butyl peroxybenzoate, 1-2% of a medium-temperature initiator such as tert-Butyl peroxy-2-ethylhexanoate, 5-20% of a shrinkage-reduction additive, 1-10% of thickener A, 1-3% of thickener B and 2-5% of inner demolding agent.

Abstract: A surfacing film is formed from a curable resin composition containing an epoxy novolac resin, a tri-functional or tetra-functional epoxy resin, ceramic microspheres, an amine-based curing agent, particulate inorganic fillers; and a toughening component. The surfacing film exhibits high Tg and high cross-linked density after curing, as well as high resistance to paint stripper solutions. The surfacing film is suitable for co-curing with fiber-reinforced resin composite materials. The surfacing film may optionally contain electrically conductive additives to provide sufficient conductivity for lightning strike protection (LSP) or electromagnetic interference (EMI) shielding.

Abstract: Provided herein are compositions useful as ink or coatings which contain novel dispersants that are capable of dispersing pigments which are traditionally difficult to disperse while maintaining acceptable levels of viscosity. Use of dispersants as taught herein enables the preparation of a wide variety of inks and coatings having high pigment loading and existing within a conventionally-useful viscosity range.

Abstract: A resin composition which has low stress, and good adhesive property in high temperature and high moisture environments and which is useful in adhesive applications in low stress, high moisture sensitivity level electronic packages. Preferably, a flexible epoxy anhydride adduct modified solid bismaleimide and solid benzoxazine resin composition that can survive high temperature and high moisture conditions and maintain good adhesion strength and minimize the stress resulting from a coefficient of thermal expansion mismatch between a silicon die and a substrate which is Ball Grid Array solder mask or a smart card polyethylene terephthalate or silver or copper metal lead frame.

Abstract: A family of carboxylic acid groups containing fluorene/fluorenon copolymers is disclosed as binders of silicon particles in the fabrication of negative electrodes for use with lithium ion batteries. Triethyleneoxide side chains provide improved adhesion to materials such as, graphite, silicon, silicon alloy, tin, tin alloy. These binders enable the use of silicon as an electrode material as they significantly improve the cycle-ability of silicon by preventing electrode degradation over time. In particular, these polymers, which become conductive on first charge, bind to the silicon particles of the electrode, are flexible so as to better accommodate the expansion and contraction of the electrode during charge/discharge, and being conductive promote the flow battery current.

Abstract: The present disclosure provides a liquid curing agent composition comprising at least 50% by weight of a polyamine and 0.2% to 10% by weight of dicyandiamide, the amine/epoxy composition and the product from the cured amine/epoxy composition.

Abstract: The present invention concerns a method of preparing a hybrid fiber including polyamide and polyester. Particularly, the method of preparing a hybrid fiber comprises, forming a blend by melting a) 4.99 to 95% by weight of a thermoplastic polyamide resin, b) 4.99 to 95% by weight of a thermoplastic polyester resin, and c) 0.01 to 10% by weight of an epoxy resin at 250 to 300° C., and blend spinning and elongating 10 to 90% by weight of the blend with 90 to 10% by weight of a polyester resin. The hybrid fiber shows highly improved compatibility of the polyamide resin and the thermoplastic polyester resin, and shows excellent strength and elongation.

Abstract: A method for preparing poly(butylene terephthalate-co-adipate) copolymer includes reacting (i) poly(butylene terephthalate-co-adipate) oligomers, wherein the oligomers comprise at least one polymer residue derived from a polyethylene terephthalate component and a quencher, with (ii) a chain extender under conditions sufficient to form the poly(butylene terephthalate-co-adipate) copolymer.

Abstract: Disclosed is a thermoplastic melt-mixed composition including: a) a polyamide resin; b) a polyetherol compound provided by reacting: b1) one or more polyepoxy compound having at least two or more epoxy groups; and b2) one or more polyhydric alcohols having two or more hydroxyl groups; c) 10 to 60 weight percent of reinforcing agent; d) 0 to 30 weight percent polymeric toughener; and e) 0 to 10 weight percent further additives. Also disclosed are molded parts derived from the composition.

Abstract: A process for preparing a reinforced and reactive thermoplastic composition having a continuous phase based on a thermoplastic polymer and dispersed therein is a discontinuous phase based on a reactive reinforcing agent that may be immiscible with the thermoplastic polymer is provided. A composition obtained by this process is also provided. The reinforcing agent is selected from the group consisting of epoxy resins, polyorganosiloxanes having SiH functional group(s), diisocyanates or polyisocyanates and mixtures thereof, comprises a grafting, a branching and/or a crosslinking, that are carried out in situ, by reactive compounding of these phases with a shear rate greater than 102 s?1, of the reinforcing agent onto the chain of the thermoplastic polymer, so that the discontinuous phase is dispersed homogeneously in the continuous phase in the form of nodules having a number-average size of less than 5 ?m.

Abstract: A composition comprising: a first polymer comprising a poly(etherimide-siloxane) copolymer comprising (a) a repeating polyetherimide unit, and (b) a poly(siloxane) block unit, a second polymer different from the first polymer and comprising bromine; and optionally, a third polymer comprising a polycarbonate different from the first polymer and second polymer; wherein polysiloxane block units are present in the composition in an amount of at least 0.3 wt %, and bromine is present in the composition in an amount of at least 7.8 wt %, each based on the sum of the wt % of the first, second, and third polymers; and further wherein an article molded from the composition has an OSU integrated 2 minute heat release test value of less than 65 kW-min/m2 and a peak heat release rate of less than 65 kW/m2, and an E662 smoke test Dmax value of less than 200.

Abstract: A high-viscosity polyamide composition including a branched polyamide is described. Also described, is a relationship between a high-viscosity polyamide composition and a composition including a copolyamide of a statistical tree type resulting from a reaction between a multifunctional monomer including at least three reactive functions in order to form an amide function. Further described, are three reactive functions of two different types and bifunctional monomers used in the manufacture of linear polyamides. A resulting copolyamide can have a very low melt flow index relative to the linear polyamide and improved impact resistance properties. Lastly, use of such a composition for extrusion blow-molding articles is described.

Abstract: A solid dry to the touch at ambient temperature structural adhesive which can be cured at elevated temperature and which can be moulded at an intermediate temperature is provided as well as the use of the adhesive for bonding metals.

Abstract: An adhesive for anchoring materials in or to concrete or masonry exhibits a shorter cure time than previous adhesives and comprises an epoxy compound and a curing agent of at least one aliphatic amine and at least one tertiary amine, optionally with a reactive dilent, which possesses sufficent strength to pass ICBO Heat Creep Test at 110 degrees F. and the ICBO Damp Hole Test at 75 degrees F.

Abstract: It is an object to provide a liquid thermosetting composition that yields an epoxy resin having physical properties of the cured product such as high flexural strength along with adequate handleability as liquid, to be used in transparent sealants for optical semiconductors, such as transparent sealants for LEDs (light-emitting devices) and the like. There is provided a thermosetting composition containing an epoxy compound that a side chain between a triazinetrione ring and an epoxy group substituted on the triazinetrione ring is long (elongated).

Abstract: The present invention relates to copolymers for solar cells based on acridonic units comprising: a monomeric unit (A) having general formula (I) wherein X is S or Se, Y is 0, S or NR? and R, R?, the same or different, are C4-C24 alkyl groups, aryl groups optionally substituted with other functional groups, acyl groups or thioacyl groups; at least one monomer unit (B) having general formula (II) wherein Z is 0, S, Se or N—R?, wherein R? is a C4-C24 alkyl group, an aryl group optionally substituted with other functional groups, an acyl group or thioacyl group, said monomeric unit (B) being connected to any position available of a hetero-aromatic side ring of the unit (A) through one of the two positions indicated by the dashed lines in general formula (II). Photovoltaic devices comprising said alternating ?-conjugated polymers are also described.

Abstract: A halogen-free resin composition, a copper clad laminate using the same, and a printed circuit board using the same are introduced. The halogen-free resin composition comprising (A) 100 parts by weight of epoxy resin; (B) 3 to 15 parts by weight of diaminodiphenyl sulfone (DDS); and (C) 5 to 70 parts by weight of phenolic co-hardener. The halogen-free resin composition features specific ingredients and proportion to thereby achieve satisfactory maximum preservation period of the prepreg manufactured from the halogen-free resin composition, control the related manufacturing process better, and attain satisfactory laminate properties, such as a high degree of water resistance, a high degree of heat resistance, and satisfactory dielectric properties, and thus is suitable for producing a prepreg or a resin film to thereby be applicable to copper clad laminates and printed circuit boards.

Abstract: Compositions including a blend of a) a polysulfone (PSU); b) a polyphenylene sulfide (PPS); and, c) a polyetherimide and epoxy. The polyetherimide and epoxy can be present in an amount effective to act as a compatibilizer for the polysulfone (PSU) and polyphenylene sulfide (PPS). Various embodiments relate to a method of compatibilizing a blend of polysulfone (PSU) and polyphenylene sulfide (PPS). The method can include a) melt mixing a polysulfone (PSU) and a polyetherimide; and b) melt mixing a polyphenylene sulfide (PPS) and an epoxy. Step a) and b) can be carried out by one of sequential mixing and simultaneous mixing.

Abstract: Crosslinked polyimide-poly(alkylene oxide) copolymers capable of holding large volumes of liquid while maintaining good dimensional stability. Copolymers are derived at ambient temperatures from amine endcapped amic-acid oligomers subsequently imidized in solution at increased temperatures, followed by reaction with trifunctional compounds in the presence of various additives. Films of these copolymers hold over four times their weight at room temperature of liquids such as ionic liquids (RTIL) and/or carbonate solvents. These rod-coil polyimide copolymers are used to prepare polymeric electrolytes by adding to the copolymers various amounts of compounds such as ionic liquids (RTIL), lithium trifluoromethane-sulfonimide (LiTFSi) or other lithium salts, and alumina.

Abstract: Epoxy containing phosphonate monomers, polymers, copolymers, oligomers and co-oligomers and methods for making the same are describes herein. These materials can be used to make polymers, and can be combined with other polymers, oligomers or monomer mixtures to make resins with excellent fire resistance that can be used in a variety of industrial and consumer products.

Abstract: Methods for forming high molecular weight chain-extended condensation polymers are disclosed. The methods include adding a chain extender during the polymerization process of a condensation polymer to provide a chain-extended condensation polymer, wherein the chain extender comprises a polymerization product of at least one epoxy-functional (meth)acrylic monomer, and at least one styrenic and/or (meth)acrylic monomer.

Abstract: The invention relates to a process for preparing a reinforced and reactive thermoplastic composition having a continuous phase which is based on at least one thermoplastic polymer and dispersed in which is a discontinuous phase based on at least one reactive reinforcing agent that may be immiscible with said at least one thermoplastic polymer, and also to a composition obtained by this process.

Abstract: Compositions of PHAs with PBS and/or PBSA are described and methods of making the same.

Abstract: This invention relates to an insulating film for a printed circuit board having improved thermal conductivity, a manufacturing method thereof and a printed circuit board using the same, wherein the insulating film includes an amphiphilic block copolymer having a vertical structure formed in a thickness direction by chemically coupling a hydrophilic compound with a hydrophobic compound.

Abstract: A gas separation membrane having a polyimide structure. The polyimide structure is provided to contain a repeating unit represented by general formula (1): (In the formula, R1 is a divalent organic group and R2 is a tetravalent organic group), wherein R1 is a divalent organic group represented by general formula (2): (In the formula, Raa is a single bond, an oxygen atom, a sulfur atom, —SO2— group, —CH2— group, —C(?O)— group, —C(CH3)2— group, —C(CH3)(CH2CH3)— group, —C(CF3)2— group or a divalent organic group formed by removing any two hydrogen atoms from a C3-C12 alicyclic hydrocarbon or C6-C25 aromatic hydrocarbon. Rab is a C1-C6 alkyl group. “ac” and “ad” mutually independently represent an integer of 0 to 2 such that 1?ac+ad?4. HFIP represents a —C(CF3)2OH group. A straight line that intersects with a wiggly line represents a bonding moiety).

Abstract: A curing agent composition including at least one benzylated polyamine compound. The benzylated polyamine compound is a reaction product of a benzaldehyde compound or benzyl halide compound and a polyamine according to the following formula: H2N—CH2-A-CH2-NH2 where A is a phenylene group or a cyclohexylene group. A method for making the curing agent composition and an amine-epoxy composition are also disclosed.

Abstract: A resin system containing: (i) a thermosetting resin precursor component comprising one or more multi-functional epoxy resin precursor(s) having a functionality of at least three, preferably wherein said precursor(s) are selected from a tri-functional epoxy resin precursor and/or a tetra-functional epoxy resin precursor; (ii) a thermoplastic polyamide particle component wherein the polyamide particles have a melting temperature TPA; and (iii) one or more curing agent(s), wherein the resin precursor component, the thermoplastic particle and the curing agent(s) are selected such that gelation of the epoxy matrix during the cure cycle of the resin system occurs at a gelation temperature TGEL which is at or below TPA.

Abstract: A thermosetting adhesive composition comprising (A) a modified polyamideimide resin that dissolves in organic solvents, (B) a thermosetting resin and (C) a curing agent or curing accelerator.

Abstract: The solvent resistance of epoxy resins toughened with polyethersulfone is improved by using low molecular weight polyethersulfone. The resulting thermoplastic toughened epoxy resins are useful for making prepreg for aerospace applications.

Abstract: An adhesive composition for semiconductor containing an organic-solvent-soluble polyimide (a), an epoxy compound (b) and a hardening accelerator (c), wherein per 100 wt parts of the epoxy compound (b), there are contained 15 to 90 wt parts of the organic-solvent-soluble polyimide (a) and 0.1 to 10 wt parts of the hardening accelerator (c), wherein the epoxy compound (b) contains a compound being liquid at 25° C. under 1.013×105 N/m2 and a compound being solid at 25° C. under 1.013×105 N/m2, and wherein a ratio of compound being liquid based on all the epoxy compounds is 20 wt % or more and 60 wt % or less.

Abstract: Disclosed is an epoxy resin composition which has excellent workability and excellent thermal resistance after curing. The epoxy resin composition contains a compound which has a specific imide structure obtained by reacting a diamine having a phenolic hydroxyl group, such as 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6FAP), with a tetracarboxylic dianhydride, and which has a number average molecular weight of 1,000 to 5,000; and a compound having at least two epoxy groups, such as a bisphenol A type epoxy resin.

Abstract: The invention provides an adhesive sheet which can be stuck to a wafer at low temperatures of 100° C. or below, which is soft to the extent that it can be handled at room temperature, and which can be cut simultaneously with a wafer under usual cutting conditions; a dicing tape integrated type adhesive sheet formed by lamination of the adhesive sheet and a dicing tape; and a method of producing a semiconductor device using them. In order to achieve this object, the invention is characterized by specifying the breaking strength, breaking elongation, and elastic modulus of the adhesive sheet in particular numerical ranges.

Abstract: A UV-protective water-soluble polyaminoamide comprising UV-absorbing end groups, wherein the polyaminoamide absorbs ultraviolet light radiation having a wavelength of about 200 nm to about 420 nm, compositions comprising the UV-protective polyaminoamide and methods of treating substrates with the UV-protective polyaminoamide.

Abstract: The present invention aims to provide a carboxyl group-containing polyimide, and prepolymer thereof which give a cured product highly satisfying thermosetting property, PCT resistance, solvent resistance and peel strength at the same time. The present invention relates to a terminal acid anhydride group-containing imide prepolymer which is characterized by being produced by reacting an acid anhydride group in a tetracarboxylic acid dianhydride with an isocyanate group in a diisocyanate compound, and a carboxyl group-containing polyimide which is characterized in having such a structure where the chain of said terminal acid anhydride group-containing imide prepolymer is extended via a polyol compound. The present invention also relates to a thermosetting resin composition and a flexible metal-clad laminate which utilize such carboxyl group-containing polyimide.

Abstract: Compositions and methods for forming surfactants, aqueous dispersions, and curing agents are provided. In one aspect, the invention relates to improved epoxy functional surfactants prepared by reaction of an epoxy composition and an amidoamine composition formed from a blend of acid-terminated polyoxyalkylene polyols. The improved epoxy functional surfactants may be reacted with an excess of epoxy composition and water to result in an aqueous dispersion. The amidoamone composition may be a reaction mixture of a diamine compound and an acid terminated polyoxyalkylene composition formed from two or more polyoxyalkylene polyol compounds. The epoxy functional surfactant may be reacted with amine compounds to form a compound suitable as a curing agent.

Abstract: Compositions and methods for forming surfactants, aqueous dispersions, and curing agents are provided. In one aspect, the invention relates to improved epoxy functional surfactants prepared by reaction of an epoxy composition and an amidoamine composition formed from a blend of acid-terminated polyoxyalkylene polyols. The improved epoxy functional surfactants may be reacted with an excess of epoxy composition and water to result in an aqueous dispersion. The amidoamone composition may be a reaction mixture of a diamine compound and an acid terminated polyoxyalkylene composition formed from two or more polyoxyalkylene polyol compounds. The epoxy functional surfactant may be reacted with amine compounds to form a compound suitable as a curing agent.

Abstract: To provide a resin composition that contains a solvent-soluble polyimide and can provide a film exhibiting high viscoelasticity and flexibility at high temperatures. To attain this, a polyimide resin composition is provided that includes a polyimide having a polycondensation unit of a tetracarboxylic acid dianhydride and a diamine, wherein the tetracarboxylic acid dianhydride includes an (?1) tetracarboxylic acid dianhydride represented by general formula (1), or the diamine includes an (?1) aromatic diamine represented by general formula (2), the diamine includes an (?2) aliphatic diamine represented by general formula (3) or (4), a total amour of the (?1) tetracarboxylic acid dianhydride and the (?1) aromatic diamine is 5 to 49 mol % with respect to a total amount of the tetracarboxylic acid dianhydride and the diamine, and an amine equivalent of the polyimide is 4,000 to 20,000.