Resin composition, substrate with piezoelectric film, and method for producing substrate with piezoelectric film

Abstract

The purpose of the present invention is to provide a resin composition which, when used for forming a piezoelectric film comprising piezoelectric particles bonded to each other with a binder resin, enables the piezoelectric particles to have satisfactory dispersibility and attains satisfactory in-plane evenness. This resin composition comprises the following (A) to (C): (A) a binder resin; (B) piezoelectric particles; and (C) a compound ((C) compound) having an acidic group and a structure represented by general formula (1) (R1 represents a hydrogen atom or a C1-C9 hydrocarbon group).

Description

Resin composition, substrate with piezoelectric film, and method for manufacturing substrate with piezoelectric film

[0001] The present invention relates to a resin composition, a substrate with a piezoelectric film, and a method for producing a substrate with a piezoelectric film.

[0002] In recent years, there has been an increasing need for personal authentication using biometric patterns such as a user's fingerprint, vein pattern, voiceprint, and iris as a method of identifying a user in bank ATMs (Automated Teller Machines), mobile phones, PDAs (Personal Data Assistants), and the like. Fingerprint authentication has particularly attracted attention as a personal authentication method, replacing personal identification numbers (PINs) for smartphones, a type of PDA. Known fingerprint authentication methods include optical, capacitive, and ultrasonic. While optical and capacitive methods are currently widely used, they still have issues with reading reliability and high security against forgery. On the other hand, ultrasonic methods can penetrate ultrasonic waves not only to the surface of a fingerprint but also to the interior of the finger, enabling them to read the vein pattern and blood flow inside the finger. This provides significantly higher reading reliability and anti-counterfeiting capabilities than optical and capacitive methods.

[0003] An ultrasonic fingerprint authentication device emits ultrasonic waves from a piezoelectric element, which transmits from the surface of the finger to the inside of the finger and converts the reflected ultrasonic waves into an electrical signal for detection. Materials that make up piezoelectric elements are broadly classified into inorganic piezoelectric materials and organic piezoelectric materials. Piezoelectric particles, typified by lead zirconate titanate (PZT), are widely used as inorganic piezoelectric materials, while organic piezoelectric materials include polyvinylidene fluoride (hereinafter referred to as PVDF), vinylidene fluoride-trifluoroethylene copolymer, polylactic acid, etc. Inorganic piezoelectric materials have superior power generation performance compared to organic piezoelectric materials, but are inferior in flexibility and impact resistance, so are usually used in combination with a binder resin. (Patent Document 1)

[0004] Japanese Patent Application Laid-Open No. 2005-22909

[0005] However, in a piezoelectric film containing piezoelectric particles and in which the piezoelectric particles are fixed with a binder resin, there is a problem that the in-plane uniformity of the piezoelectric properties deteriorates due to localization of the piezoelectric particles. Therefore, an object of the present invention is to provide a resin composition that enables good dispersion of the piezoelectric particles and good in-plane uniformity to be obtained in a piezoelectric film in which the piezoelectric particles are fixed with a binder resin.

[0006] The present invention is as follows: (1) A resin composition containing the following (A) to (C): (A) a binder resin; (B) piezoelectric particles; and (C) a compound having a structure represented by general formula (1) and an acidic group ((C) compound).

[0007]

[0008] R １represents hydrogen or a hydrocarbon group having 1 to 9 carbon atoms. (2) The resin composition according to (1), wherein the (B) piezoelectric particles are perovskite-type oxides. (3) The resin composition according to (1) or (2), wherein the (B) piezoelectric particles contain at least one selected from lead zirconate titanate, niobium pentoxide, potassium niobate, magnesium niobate, sodium niobate, potassium sodium niobate (KNN), and composite compounds thereof. (4) The resin composition according to any one of (1) to (3), wherein the (B) piezoelectric particles have an average particle size of 300 to 1,800 nm. (5) The resin composition according to any one of (1) to (4), wherein the (C) compound has an acid value of 50 to 150 mg KOH / g. (6) The resin composition according to any one of (1) to (5), wherein the (C) compound has a weight-average molecular weight MW of 5,000 to 50,000. (7) The resin composition according to any one of (1) to (6), wherein the (C) compound further has a carbon-carbon double bond. (8) The resin composition according to any one of (1) to (7), further comprising a (D) reactive monomer, wherein the (D) reactive monomer contains two or more reactive groups of at least one type selected from an epoxy group, an oxetane group, a (meth)acrylic group, and a methylol group. (9) The resin composition according to any one of (1) to (8), further comprising an (E) curing agent. (10) A piezoelectric film-attached substrate having a piezoelectric film obtained by curing the resin composition according to any one of (1) to (9). (11) A method for producing a piezoelectric film-attached substrate, comprising the steps of: applying the resin composition according to any one of (1) to (9) to a substrate; and curing the resulting coating film by exposure and / or heating at 80 to 300°C.

[0009] The resin composition of the present invention can provide a piezoelectric film having excellent power generation performance and in which piezoelectric particles are uniformly distributed.

[0010] Preferred embodiments of the resin composition of the present invention will be specifically described below, but the present invention is not limited to the following embodiments and can be practiced with various modifications depending on the purpose and application.

[0011] The resin composition of the present invention is a resin composition containing (A) a binder resin, (B) piezoelectric particles, and (C) a compound ((C) compound) having a structure represented by general formula (1) and an acidic group, and has appropriate fluidity before curing, allowing it to be applied to a substrate. After application, a piezoelectric film can be formed by photocuring and / or thermal curing at 80 to 300°C. The piezoelectric film of the present invention is obtained by curing the resin composition of the present invention, and contains piezoelectric particles, with the piezoelectric particles fixed with a binder resin. The piezoelectric film-coated substrate of the present invention is a substrate having a piezoelectric film formed by curing the resin composition of the present invention, and the piezoelectric film is formed on the substrate.

[0012] <(A) Binder Resin> The (A) binder resin used in the present invention is a binding component made of a natural resin and / or a synthetic resin, and functions to fix the (B) piezoelectric particles and improve the flexibility of the formed piezoelectric film. The content of the (A) binder resin in the solid content of the resin composition is preferably 1% by mass or more, more preferably 2% by mass or more. On the other hand, from the viewpoint of the piezoelectric particle density in the formed piezoelectric film, the content of the (A) binder resin in the solid content of the resin composition is preferably 20% by mass or less, more preferably 15% by mass or less. Here, the solid content of the resin composition refers to all components contained in the resin composition, excluding volatile components such as solvents. The amount of solid content of the resin composition can be determined by heating the resin composition and measuring the residue after evaporating the volatile components.

[0013] Preferred examples of the (A) binder resin include epoxy resin, polysiloxane, polyimide, polyimide precursor, polybenzoxazole, polybenzoxazole precursor, polyamideimide, cardo polymer, (meth)acrylic resin, novolac resin, etc. Among these, (meth)acrylic resin is particularly preferred from the viewpoint of flexibility, dispersibility of piezoelectric particles, etc.

[0014] The (meth)acrylic resin is preferably a copolymer of an acrylic monomer having a carbon-carbon double bond with another monomer. Examples of the acrylic monomer having a carbon-carbon double bond include acrylates having a chain aliphatic hydrocarbon group having 1 to 18 carbon atoms, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, isodecyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, allyl acrylate, lauryl acrylate, and stearyl acrylate; benzyl acrylate, phenyl acrylate, and the like. Examples of suitable copolymers include acrylates having a cyclic aromatic hydrocarbon group having 6 to 10 carbon atoms, such as acrylate, 1-naphthyl acrylate, and 2-naphthyl acrylate; acrylates having a cyclic aliphatic hydrocarbon group having 6 to 15 carbon atoms, such as cyclohexyl acrylate, dicyclopentanyl acrylate, 4-tert-butylcyclohexyl acrylate, dicyclopentenyl acrylate, dicyclopentadienyl acrylate, isobornyl acrylate, and 3,3,5-trimethylcyclohexyl acrylate, as well as acrylates obtained by replacing these acrylates with methacrylates. Two or more of these may be used. Examples of copolymerization components other than acrylic monomers include acrylonitrile; acrylamide; styrenes such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, chloromethylstyrene, and hydroxymethylstyrene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, and vinylacetic acid, and acid anhydrides thereof. Two or more of these may be used.

[0015] The (meth)acrylic resin preferably has a curable group in the side chain or molecular end, which can improve the curing reaction rate during exposure or heating. As the curable group, an epoxy group or a group having a carbon-carbon double bond is suitably used, and a group having a carbon-carbon double bond is particularly preferred. The presence of a group having a carbon-carbon double bond can improve the toughness of the piezoelectric film. Examples of structures having a carbon-carbon double bond include a vinyl group, an allyl group, and a (meth)acrylic group. Two or more of these may be present. Methods for introducing a carbon-carbon double bond into an acrylic resin include, for example, reacting a mercapto group, amino group, hydroxyl group, or carboxyl group in the acrylic resin with a compound having a glycidyl group or an isocyanate group and a carbon-carbon double bond, acrylic acid chloride, methacrylic acid chloride, allyl chloride, or the like.

[0016] Examples of compounds having a glycidyl group and a carbon-carbon double bond include glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, glycidyl ethyl acrylate, crotonyl glycidyl ether, glycidyl crotonate, glycidyl isocrotonate, Cyclomer (registered trademark) M100, A200 (all manufactured by Daicel Corporation). Examples of compounds having an isocyanate group and a carbon-carbon double bond include acryloyl isocyanate, methacryloyl isocyanate, acryloylethyl isocyanate, methacryloylethyl isocyanate, etc. Two or more of these may be used.

[0017] <(B) Piezoelectric Particles> The (B) piezoelectric particles used in the present invention are made by processing ceramics having ferroelectric properties into a powder form, and can exhibit piezoelectric properties by converting electrical energy and kinetic energy. The (B) piezoelectric particles preferably contain metal atoms and oxygen atoms. The misalignment of the charge centers of the metal atoms and oxygen atoms improves piezoelectric performance. Furthermore, the presence of an acidic moiety derived from the oxygen atoms and a basic moiety derived from the metal atoms is preferable because it improves dispersibility as described below.

[0018] The (B) piezoelectric particles are preferably piezoelectric particles having a perovskite crystal structure. That is, the (B) piezoelectric particles are preferably perovskite oxides. By adopting a perovskite crystal structure, due to properties unique to certain elements, such as the covalent bond between metal and oxygen and the lone electron pairs of metals, centrosymmetry is broken in the crystal structure, resulting in excellent piezoelectric properties. Examples of piezoelectric particles having a perovskite crystal structure include ternary transition metal oxides such as barium titanate, lead titanate, lead zirconate titanate, and potassium sodium niobate. Examples of piezoelectric particles not having a perovskite crystal structure include potassium sodium tartrate and niobium pentoxide.

[0019] From the viewpoint of piezoelectric properties, the (B) piezoelectric particles preferably contain one or more of the elements niobium, lead, titanium, zinc, barium, bismuth, zirconium, lanthanum, potassium, sodium, calcium, and magnesium. Of these, it is more preferable that the piezoelectric particles do not contain lead, because this is safe for the human body and the environment.

[0020] (B) The piezoelectric particles preferably contain at least one selected from barium titanate, lead zirconate titanate, niobium pentoxide, potassium niobate, magnesium niobate, sodium niobate, potassium sodium niobate (KNN), and composite compounds thereof, more preferably at least one selected from barium titanate, lead zirconate titanate, potassium niobate, magnesium niobate, sodium niobate, potassium sodium niobate (KNN), and composite compounds thereof, and more preferably at least one selected from lead zirconate titanate, niobium pentoxide, potassium niobate, magnesium niobate, sodium niobate, potassium sodium niobate (KNN), and composite compounds thereof. Barium titanate particles and KNN particles are particularly preferred because of their excellent piezoelectric properties and safety to the human body and the environment.

[0021] (B) The piezoelectric particles may contain other metal components. For example, the KNN particles may contain alkali metals such as Li (lithium) in addition to K (potassium) and Na (sodium), and may also contain alkaline earth metals such as Ca (calcium), Sr (strontium), Ba (barium), Ta (tantalum), and Sb (antimony) in addition to Nb (niobium). Furthermore, the KNN particles may contain small amounts of Bi (bismuth), Fe (iron), Al (aluminum), Mn (manganese), Co (cobalt), Ni (nickel), etc.

[0022] The content of the (B) piezoelectric particles is preferably 30% by mass to 90% by mass, more preferably 60% by mass to 80% by mass, based on the solid content of the resin composition. A content of 30% by mass or more can improve the piezoelectric properties, and a content of 90% by mass or less can improve the flexibility of the piezoelectric film.

[0023] The average particle size of the (B) piezoelectric particles is preferably 300 to 1800 nm, and more preferably 500 to 1200 nm. By making the particle size 300 nm or more, the specific surface area of ​​the particles can be suppressed, thereby improving the flow characteristics and processing characteristics even when the content of (A) binder resin is low. By making the particle size 1800 nm or less, the surface of the formed piezoelectric film can be smoothed and noise can be reduced. These particle sizes are calculated as median diameters from particle size distributions measured by laser diffraction using a particle size distribution analyzer (N4-PLUS; manufactured by Beckman Coulter, Inc.) or the like.

[0024] <Compound (C)> The resin composition of the present invention contains a compound (C) having a structure represented by general formula (1) and an acidic group (compound (C)).

[0025]

[0026] R １ represents hydrogen or a hydrocarbon group having 1 to 9 carbon atoms. Particularly preferred is an alkyl group having 1 to 6 carbon atoms. Most preferred is R １ is hydrogen, a methyl group, or an ethyl group.

[0027] The present inventors have found that the inclusion of compound (C) in the resin composition of the present invention dramatically improves the dispersibility of piezoelectric particles. The improved dispersibility of piezoelectric particles results in uniform distribution of piezoelectric particles in a piezoelectric film using the resin composition of the present invention, resulting in reduced surface roughness. In particular, when the piezoelectric particles (B) contain metal atoms and oxygen atoms, they have acidic moieties derived from oxygen atoms and basic moieties derived from metal atoms. This is thought to be because the structure of compound (C) represented by general formula (1) interacts with the acidic moieties derived from oxygen atoms on the surface of the piezoelectric particles, and the compound having an acidic group interacts with the basic moieties derived from metal atoms on the surface of the piezoelectric particles. It is preferable for compound (C) to have two or more structures represented by general formula (1) and two or more acidic groups, as this further improves dispersibility.

[0028] The content of the (C) compound is preferably 0.01 to 5.0 mass% relative to the solid content of the resin composition. More preferably, it is 0.3 to 3 mass%. By setting the content of the (C) compound to 0.01 mass% or more, the dispersibility of the piezoelectric particles can be improved, and by setting it to 5.0 mass% or less, the strength of the piezoelectric film can be made sufficient.

[0029] Examples of the structure represented by general formula (1) include an amide structure and a urethane structure. A urethane structure is preferred from the viewpoint of suppressing reaction with the binder resin in the resin composition and improving storage stability. That is, the compound (C) is preferably an amide resin or a urethane resin, and particularly preferably a urethane resin. A suitable method for introducing a urethane structure is, for example, a reaction between an isocyanate compound and various nucleophiles.

[0030] Examples of the isocyanate compound include methyl isocyanate (MIC), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI). In order to introduce two or more structures represented by general formula (1), MDI, HDI, TMHDI, TDI, and IPDI are preferred, and HDI and TMHDI are particularly preferred from the viewpoint of interaction with piezoelectric particles.

[0031] As the nucleophilic agent, an epoxy compound is preferred, and an epoxy compound having two or more epoxy groups is particularly preferred. By using such a compound, two or more structures represented by general formula (1) can be introduced. Although the epoxy compound having two or more epoxy groups is not particularly limited, a compound represented by general formula (2) is preferred from the viewpoint of the toughness of the resin composition coating film.

[0032]

[0033] R ２ are each independently a hydrogen atom, a methyl group, a trifluoromethyl group, L ２ each independently represents a divalent organic group. ２ It is preferable that L has an alkylene oxide group having 1 to 6 carbon atoms in order to improve the reaction rate. ２ is more preferably an alkylene oxide group having 1 to 6 carbon atoms. ２ is an alkylene oxide group having 1 to 3 carbon atoms.

[0034] The acidic group of the (C) compound refers to a functional group capable of donating hydrogen ions. Specific examples include phenolic hydroxyl groups, carboxyl groups, silanol groups, sulfo groups, and phosphine oxide groups. From the viewpoint of interaction with piezoelectric particles, carboxyl groups are particularly preferred. The amount of acidic groups introduced is preferably adjusted so that the acid value of the (C) compound is 50 to 150 mg KOH / g. That is, the acid value of the (C) compound is preferably 50 to 150 mg KOH / g. By setting the acid value to 50 mg KOH / g or more, the effect of improving the dispersibility of the (B) piezoelectric particles can be maintained, while by setting the acid value to 150 or less, the storage stability of the resin composition can be improved. An acid value of 70 to 120 mg KOH / g is even more preferred. The (C) compound is preferably a polymer such as an acrylic resin, a urethane resin, an epoxy resin, a polyimide resin, or a polybenzoxazole resin, as this further improves interaction with the piezoelectric particles. Urethane resins and epoxy resins are even more preferred. The weight average molecular weight MW of the (C) compound is preferably 5,000 to 50,000. By making the MW 5,000 or more, the effect of improving the dispersibility of the (B) piezoelectric particles can be maintained, and by making the MW 50,000 or less, the fluidity of the resin composition can be improved, thereby improving the flatness of the coating surface. A MW of 8,000 to 20,000 is even more preferable.

[0035] The (C) compound preferably further has a carbon-carbon double bond. By having a carbon-carbon double bond, it reacts with the (A) binder resin, and the strength of the resin composition coating film can be increased. From the viewpoint of reactivity, the carbon-carbon double bond is preferably a (meth)acrylic group.

[0036] Examples of methods for introducing a carbon-carbon double bond include reacting a terminal isocyanate group generated by reacting an isocyanate compound with a nucleophile, and then reacting the resulting terminal isocyanate group with a compound having a hydroxyl group and a carbon-carbon double bond.

[0037] <(D) Reactive Monomer> The resin composition of the present invention may further contain (D) a reactive monomer. Here, the reactive monomer refers to a compound having a reactive functional group. Examples of the reactive functional group include an epoxy group, an oxetane group, a (meth)acrylic group, and a methylol group. As the (D) reactive monomer, one containing two or more reactive groups of at least one type selected from an epoxy group, an oxetane group, a (meth)acrylic group, and a methylol group is preferably used.

[0038] Examples of compounds having an epoxy group include glycidyl ethers of aliphatic alcohols, glycidyl ethers of phenols, glycidyl ethers of alkylene glycols, glycidyl ethers of phenoxyalkyl alcohols, glycidyl ethers of saturated or unsaturated fatty acids, and low-molecular-weight epoxy compounds having at least one epoxy group in the molecule, such as aliphatic or aromatic olefin epoxides, and examples thereof include butyl glycidyl ether, allyl glycidyl ether, hexanediol diglycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, butanediol glycidyl ether, and glycidyl esters of acrylic acid or methacrylic acid.

[0039] Examples of compounds having an oxetane group include OXT-121, OXT-221, OX-SQ-H, OX-SC, PNOX-1009, and RSOX (all trade names, manufactured by Toagosei Co., Ltd.), Ethanacol OXBP, and Ethanacol OXTP (all trade names, manufactured by Ube Industries, Ltd.).

[0040] Examples of the compound having a (meth)acrylic group include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, trimethylolpropane dimethacrylate, trimethylolpropane trimethacrylate, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, neopentyl glycol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol dimethacrylate, dimethylol-tricyclodecane diacrylate, acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tripentaerythritol heptaacrylate, tripentaerythritol octaacrylate, tetrapentaerythritol nonaacrylate, tetrapentaerythritol decaacrylate, pentaerythritol undecaacrylate, pentaerythritol dodecaacrylate, tripentaerythritol heptamethacrylate, tripentaerythritol octamethacrylate, tetrapentaerythritol nonamethacrylate, tetrapentaerythritol decamethacrylate, pentaerythritol undecamethacrylate, pentaerythritol dodecamethacrylate, and dimethylol tricyclodecane diacrylate.

[0041] Examples of compounds having a methylol group include the following melamine derivatives and urea derivatives (trade names MH-30HM, MX-270, MX-280, MX-290, manufactured by Sanwa Chemical Co., Ltd.), and phenolic compounds (trade names DML-PTBP, DMOM-PTBP, TML-BPA, TMOM-BPA, TML-BPAF, TMOM-BPAF, manufactured by Honshu Chemical Industry Co., Ltd.).

[0042]

[0043] From the viewpoint of reactivity, a compound having an epoxy group is particularly preferred, and the reactive monomers may be used alone or in combination of two or more kinds.

[0044] <(E) Curing Agent> The resin composition of the present invention may further contain (E) a curing agent. The (E) curing agent serves to activate the reaction of the (D) reactive monomer. As the curing agent, an acid generator, a base generator, an acid anhydride, an amine-based latent curing agent, etc. can be selected.

[0045] The curing agent and acid generator are compounds that generate an acid upon irradiation with light and / or heating, and the acid generated is preferably a strong acid such as perfluoroalkylsulfonic acid or p-toluenesulfonic acid.

[0046] Specific examples of acid generators that can be preferably used include SI-100, SI-101, SI-105, SI-106, SI-109, PI-105, PI-106, PI-109, NAI-100, NAI-1002, NAI-1003, NAI-1004, NAI-101, NAI-105, NAI-106, NAI-109, NDI-101, NDI-105, NDI-106, NDI-109, PAI-01, PAI-101, PAI-106, and PAI-1001 (all trade names, manufactured by Midori Chemical Industry Co., Ltd.); Examples of such polyisoprene include SP-077 and SP-082 (trade names, manufactured by ADEKA Corporation), TPS-PFBS (trade name, manufactured by Toyo Gosei Co., Ltd.), CGI-MDT and CGI-NIT (trade names, manufactured by Ciba Japan Co., Ltd.), WPAG-281, WPAG-336, WPAG-339, WPAG-342, WPAG-344, WPAG-350, WPAG-370, WPAG-372, WPAG-449, WPAG-469, WPAG-505, and WPAG-506 (trade names, manufactured by Wako Pure Chemical Industries, Ltd.).

[0047] An onium salt compound can also be used as the acid generator. Specific examples of the onium salt compound include diazonium salts, ammonium salts, iodonium salts, sulfonium salts, phosphonium salts, and oxonium salts. Preferred onium salt compounds include diphenyliodonium triflate, diphenyliodonium pyrenesulfonate, diphenylpyrenedodecylbenzenesulfonate, triphenylsulfonium triflate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium naphthalenesulfonate, and (hydroxyphenyl)benzylmethylsulfonium toluenesulfonate. These compounds may be used alone or in combination of two or more.

[0048] The content of the acid generator in the resin composition of the present invention is not particularly limited, but is in the range of 0.01 to 5 parts by mass relative to the solid content of the resin composition. When the content is 0.01 part by mass or more, the effect becomes greater, and when it is 5 parts by mass or less, the storage stability becomes better.

[0049] As the curing agent or base generator, any agent that generates a base upon light irradiation and / or thermal curing may be used, and examples thereof include 1,5,7-triazacyclo[4,4,0]dec-5-ene 2-(9-oxoxanthen-2-yl)propionate, 1-(anthraquinone-2-yl)ethyl N-cyclohexylcarbamate, 9-anthrylmethyl N,N-diethylcarbamate, 9-anthrylmethyl N-cyclohexylcarbamate, 9-anthrylmethylpiperidine 1-carboxylate, and 9-anthrylmethyl N,N-dicyclohexylcarbamate. , 1-(anthraquinone-2-yl)ethyl N,N-dicyclohexylcarbamate, 2-(3-benzoylphenyl)cyclohexylammonium propionate, 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium butyltriphenylboronate, 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidinium 2-(3-benzoylphenyl)propionate, (2-nitrophenyl)methyl 4-hydroxypiperidine-1-carboxylic acid, guanidinium 2-(3-benzoylphenyl)propionate, etc. Two or more of these may be used.

[0050] The content of the base generator in the resin composition of the present invention is preferably 0.5% by mass or more, and from the viewpoint of storage stability, preferably 2.0% by mass or less, based on the solid content of the resin composition.

[0051] As the curing agent, examples of acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, himic anhydride, succinic anhydride, trimellitic anhydride, and pyromellitic anhydride, and these may be used alone or in combination of two or more.

[0052] The content of the acid anhydride in the resin composition of the present invention is preferably 0.5 to 7 mass %, more preferably 1.0 to 5 mass %, based on the solid content of the resin composition.

[0053] As the amine-based latent curing agent, an active hydrogen-containing amine-based latent curing agent is preferred because of its excellent reactivity. Specific examples include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyoxypropylenediamine, polyoxypropylenetriamine, isophoronediamine, menthenediamine, bis(4-amino-3-methyldicyclohexyl)methane, diaminodicyclohexylmethane, bis(aminomethyl)cyclohexane, N-aminoethylpiperazine, m-phenylenediamine, p-phenylenediamine, tolylene-2,4-diamine, mesitylene-2,6-diamine, 4,4-diaminodiphenylmethane, 2,6-naphthylenediamine, and 2-aminopropylimidazole.

[0054] The content of the amine-based latent curing agent in the resin composition of the present invention is preferably 0.001% by mass to 5% by mass, more preferably 0.01% by mass to 3% by mass, based on the solid content of the resin composition. A content of 0.001% by mass or more ensures sufficient curing, while a content of 5% by mass or less reduces unreacted materials and provides a film with good properties.

[0055] In the present invention, the resin composition may contain a surfactant as a leveling agent. By including a surfactant, flow properties during application can be improved. Examples of such surfactants include fluorine-based surfactants such as "Megafac" (registered trademark) F142D, F172, F173, F183, F445, F470, F475, and F477 (all trade names, manufactured by Dainippon Ink and Chemicals, Inc.), and NBX-15 and FTX-218 (all trade names, manufactured by Neos Corporation); silicone-based surfactants such as "BYK" (registered trademark) -333, 301, 331, 345, and 307 (all trade names, manufactured by BYK Japan KK); polyalkylene oxide-based surfactants; and poly(meth)acrylate-based surfactants. Two or more of these surfactants may be included.

[0056] Furthermore, for the purpose of improving adhesion to the substrate, the resin composition may contain an adhesion improver. Examples of the adhesion improver include silane coupling agents. Specific examples of silane coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N-β(aminoethyl)γ-amino Examples include propylmethyldimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, bis(triethoxypropyl)tetrasulfide, γ-isocyanatopropyltriethoxysilane, etc. These may be used alone or in combination of two or more.

[0057] The content of the adhesion improver in the resin composition of the present invention is usually 0.1 to 5.0% by mass, preferably 0.3 to 3.0% by mass, based on the solid content of the resin composition.

[0058] The resin composition is produced by adding (A) a binder resin, (B) piezoelectric particles, (C) a compound having a structure represented by general formula (1) and an acidic group, and, if necessary, (D) a reactive monomer, (E) a curing agent, a leveling agent, an adhesion improver, a solvent, etc., and then uniformly kneading the mixture at room temperature, usually using a three-roll mill.

[0059] The piezoelectric film-coated substrate of the present invention has a piezoelectric film formed on a substrate by curing the resin composition of the present invention. The piezoelectric film-coated substrate of the present invention is preferable because it has a piezoelectric film in which piezoelectric particles having excellent power generation performance are uniformly distributed.

[0060] The method for producing a substrate with a piezoelectric film of the present invention preferably includes a step of applying the resin composition of the present invention to a substrate, and a step of curing the resulting coating film by exposure to light and / or heating at 80 to 300°C.

[0061] Examples of methods for applying the resin composition include screen printing and slit coating. Examples of screen printing include a method in which a photosensitive emulsion mask is formed in a pattern as needed on a 200-400 mesh stainless steel screen, and a polyurethane squeegee is used to form a coating film of the resin composition on a substrate with a desired thickness. Examples of slit coating include a method in which a die with a width of 100 mm and a clearance of 0.2 mm is used to extrude the resin composition by compressed air, thereby forming a coating film on a substrate with a desired thickness.

[0062] When the resin composition contains a solvent, the composition may include a drying step of removing the solvent by heating at about 110° C. after application to the substrate.

[0063] Methods for curing the coating film include photocuring by exposure to light and thermal curing by heating, and these may be combined. In the case of photocuring, high-power UV light of about 80 to 150 W is used to cure the film by short exposure times of seconds, and high performance characteristics can be expected. In the case of thermal curing, thermal curing is preferably carried out at 80 to 300°C for about 15 minutes to 2 hours. Drying devices used for thermal curing include, for example, a hot air oven and a hot plate.

[0064] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0065] <Evaluation of Resin Composition> 1. Storage Stability After regulating the temperature of the resin composition for 3 minutes in a thermostatic bath at 25°C, the viscosity was measured at atmospheric pressure using a Brookfield viscometer (Brookfield viscometer, model HB DV-I; manufactured by Eiko Seiki Co., Ltd.) at a rotation speed of 10 rpm. The viscosity 1 day after preparation of the resin composition was defined as η1, and the viscosity 5 days after preparation as η2, and the ratio of η1 to η2 (η2 / η1) was calculated. 4: η2 / η1≦1.2 3: 1.2<η2 / η1≦1.5 2: 1.5<η2 / η1≦2.0 1: 2.0<η2 / η1.

[0066] 2. Screen Printability The paste obtained in each Example and Comparative Example was applied to a PET film (S10 "Lumirror" (registered trademark) #125; manufactured by Toray Industries, Inc.) by screen printing in multiple layers so that the film would have a dry thickness of 10 μm, and each was dried in a hot air dryer at 70° C. for 10 minutes to obtain a dried film of the paste on the PET film. The coating was performed by changing the gap between the screen and the stage, and the smallest gap d that allowed for uniform coating over the entire surface was evaluated according to the following criteria: 4: d≦1.0 3: 1.0<d≦2.0 2: 2.0<d 1: Cannot be printed.

[0067] <Evaluation of Various Piezoelectric Films> 1. Uniformity The density (D1) of the piezoelectric film was measured for 10 samples as follows, and the 3σ was calculated. (1) The mass of a PET film (S10 "Lumirror" #125; manufactured by Toray Industries, Inc.) was measured. (W1) (2) A 10 μm-thick emulsion was formed on the PET film by screen printing using a 200-mesh stainless steel screen. (3) The formed piezoelectric film was cured by heat or UV. (4) The mass including the PET film after curing was measured. (W2) (5) The thickness (T1) of the piezoelectric film was measured using a surface roughness meter (surface roughness and shape measuring instrument ("Surfcom" (registered trademark) 1400D manufactured by Tokyo Seimitsu Co., Ltd.)). The density (D1) of the piezoelectric film for 10 samples was calculated using the following formula, and their standard deviation σ was calculated. Evaluation was based on the following criteria. D1=(W2-W1) / (6×6×T1) 4: σ≦0.10 3: 0.10<σ≦0.15 2: 0.15<σ≦0.20 1: 0.20<σ.

[0068] 2. Measurement of surface roughness (Ra (average roughness), Rz (maximum roughness) of cured film) Using a surface roughness meter (surface roughness and profile measuring instrument ("Surfcom" (registered trademark) 1400D manufactured by Tokyo Seimitsu Co., Ltd.), the surface roughness (Ra) of a piezoelectric film with a thickness of approximately 10 μm formed on a PET film for density measurement was measured and evaluated according to the following criteria. As described above, improved dispersibility of piezoelectric particles results in uniform distribution of piezoelectric particles in a piezoelectric film using the resin composition of the present invention, reducing surface roughness and allowing evaluation of the dispersibility of piezoelectric particles. 4: σ≦0.10 3: 0.10<σ≦0.15 2: 0.15<σ≦0.20 1: 0.20<σ.

[0069] 3. Pencil hardness The pencil hardness of the piezoelectric film formed on the PET film was measured in accordance with JIS K5600-5-4 using a UNI MITSUBISHI pencil. 4: No peeling of any of the grid cells, or small peeling of the coating at the intersections of the cuts. Not clearly exceeding 5%. 3: The coating has peeled off at the intersections along the cut lines. 5% or more but less than 15%. 2: The coating has peeled off partially or completely along the cut lines. 15% or more but less than 35%. 1: The coating has peeled off significantly partially or completely along the cut lines. 35% or more but less than 65%. 0: 65% or more has peeled off.

[0070] 4. Chemical Resistance 1 ml of acetone was dropped onto the piezoelectric film formed on the PET film, and after leaving it to stand for 30 seconds, the solvent was wiped off with Toraysee (trade name; manufactured by Toray), and the state of the wiped residue was visually evaluated according to the following criteria: 4: No wiped residue 3: Wiped residue visible, but the piezoelectric film remains and the substrate is not visible 2: Part of the piezoelectric film is removed, and the substrate is visible 1: The piezoelectric film is completely removed

[0071] 5. Toughness The piezoelectric film formed on the PET film was bent at 90° and then returned to its original position, and the state of the piezoelectric film was observed and evaluated according to the following criteria: 4: No change 3: Marks were observed on the surface of the piezoelectric film, but the piezoelectric film was present and the substrate was not visible 2: Cracks occurred in the piezoelectric film, and the substrate was visible 1: The piezoelectric film peeled off from the substrate.

[0072] The compounds used in the examples and comparative examples are as follows: Binder resin (A-1): a resin obtained by addition reaction of glycidyl methacrylate with the carboxyl group of a copolymer of methacrylic acid / methyl methacrylate / styrene (molecular weight 20,000, containing double bonds) Binder resin (A-2): "KAYARAD" (registered trademark) CCR-1322H (novolac resin, Mw 8,000; manufactured by Nippon Kayaku Co., Ltd.) Piezoelectric particles (B-1): potassium sodium niobate particles (average particle diameter 500 nm) Piezoelectric particles (B-2): potassium sodium niobate particles (average particle diameter 300 nm) Piezoelectric particles (B-3): potassium sodium niobate particles (average particle diameter 2,000 nm) Piezoelectric particles (B-4): potassium sodium tartrate particles (average particle diameter 1,000 nm) Reactive monomer (D-1): CELLOXIDE 2021P (trade name; manufactured by Daicel Chemical Industries, Ltd., bifunctional epoxy compound)

[0073]

[0074] Reactive monomer (D-2): OXT-221 (trade name, manufactured by Toagosei, bifunctional oxetane compound)

[0075]

[0076] Reactive monomer (D-3): MX-270 (trade name, manufactured by Nippon Carbide, tetrafunctional methylol compound)

[0077]

[0078] Curing agent (E-1): San-Aid SI-200 (trade name; manufactured by Sanshin Chemical Industry Co., Ltd., acid generator).

[0079] Synthesis Example (C-1): Synthesis of Compound (C) Into a 3 L flask equipped with a stirrer and a reflux condenser were charged 368.0 g of RE-310S (trade name, manufactured by Nippon Kayaku, bifunctional bisphenol-A type epoxy resin, epoxy equivalent: 184.0 g / equivalent), 141.2 g of acrylic acid (molecular weight: 72.06) as a monocarboxylic acid compound (b) having an ethylenically unsaturated group in the molecule, 1.02 g of hydroquinone monomethyl ether as a thermal polymerization inhibitor, and 1.53 g of triphenylphosphine as a reaction catalyst, and the mixture was reacted at a temperature of 98°C until the acid value of the reaction solution reached 0.5 mg KOH / g or less, to obtain an epoxy carboxylate compound (theoretical molecular weight: 509.2).

[0080] Next, 755.5 g of carbitol acetate as a solvent, 268.3 g of 2,2-bis(dimethylol)-propionic acid (molecular weight: 134.16), 1.08 g of 2-methylhydroquinone as a thermal polymerization inhibitor, and 140.3 g of spiroglycol (molecular weight: 304.38) were added to this reaction solution, and the temperature was raised to 45°C. 485.2 g of trimethylhexamethylene diisocyanate (molecular weight: 210.27) was gradually added dropwise to this solution so that the reaction temperature did not exceed 65°C. After the dropwise addition was completed, the temperature was raised to 80°C and the reaction was continued for 6 hours, yielding a resin solution containing compound (C-1) containing a urethane bond as a structure represented by general formula (1) and a carboxyl group as an acidic group. The IR spectrum of the resin solution was measured, revealing a peak at 1530 (cm －１ A peak of urethane bonds was observed near 0.05°C. The acid value of the solid content was 80.0 mg KOH / g, and the weight average molecular weight was 10,000. An appropriate amount of carbitol acetate was added to the obtained resin solution to prepare a resin solution with a solid content concentration of 60% by mass.

[0081] Synthesis Examples (C-2 to C-6): Synthesis of Compound (C) The same procedure as in Synthesis Example (C-1) was repeated except for changing the amounts added as shown in Table 1, to obtain resin solutions containing compounds (C-2 to C-6) containing a urethane bond as the structure represented by general formula (1) and a carboxyl group as the acidic group. The thermal polymerization inhibitor, reaction catalyst, and solvent are not described. The IR spectrum of the resin solution was measured, revealing a peak at 1530 (cm －１The acid value of the solid content and the weight average molecular weight of the produced compound (C) are shown in Table 1.

[0082] Example 1 10 g of binder resin (A-1), 75 g of piezoelectric particles (B-1), 1.5 g of compound (C-1), 13 g of reactive monomer (D-1), and 0.5 g of curing agent (E-1) were first placed in a plastic beaker and kneaded by hand, and then kneaded four times using a three-roll mill.

[0083] Using this paste, a 60 mm square coating film was formed on a PET film using a 200-mesh stainless steel screen with an emulsion thickness of 10 μm. This was then dried with hot air at 150°C for 30 minutes. The film thickness was 10.0 μm. The results of evaluation using the above-mentioned method are shown in Table 2.

[0084] Examples 2 to 16, Comparative Examples 1 to 4 Example 1 was repeated except for the changes shown in Tables 2 and 3.

[0085]

[0086]

[0087]

Claims

1. A resin composition comprising the following (A) to (C): (A) a binder resin; (B) piezoelectric particles; and (C) a compound having a structure represented by general formula (1) and an acidic group (compound (C)). R １ represents hydrogen or a hydrocarbon group having 1 to 9 carbon atoms.

2. The resin composition according to claim 1, wherein the piezoelectric particles (B) are perovskite-type oxides.

3. The resin composition according to claim 1, wherein the (B) piezoelectric particles contain at least one selected from lead zirconate titanate, niobium pentoxide, potassium niobate, magnesium niobate, sodium niobate, potassium sodium niobate (KNN), and composite compounds thereof.

4. The resin composition according to claim 1, wherein the average particle size of the piezoelectric particles (B) is 300 to 1,800 nm.

5. The resin composition according to claim 1, wherein the acid value of the compound (C) is 50 to 150 mg·KOH / g.

6. The resin composition according to claim 1, wherein the weight average molecular weight MW of the compound (C) is 5,000 to 50,000.

7. The resin composition according to claim 1, wherein the compound (C) further has a carbon-carbon double bond.

8. The resin composition according to claim 1, further comprising (D) a reactive monomer, said (D) reactive monomer containing two or more reactive groups of at least one type selected from the group consisting of epoxy groups, oxetane groups, (meth)acrylic groups and methylol groups.

9. The resin composition according to claim 1, further comprising (E) a curing agent.

10. A substrate with a piezoelectric film, comprising a substrate and a piezoelectric film formed by curing the resin composition according to any one of claims 1 to 9.

11. A method for producing a substrate with a piezoelectric film, comprising the steps of: applying the resin composition according to any one of claims 1 to 9 onto a substrate; and curing the resulting coating film by exposure to light and / or heating at 80 to 300°C.

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