JP2010219484A - Organic piezoelectric material, ultrasonic vibrator, ultrasonic probe, and ultrasonic medical image diagnosis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide organic piezoelectric materials which have superior piezoelectric characteristics and handling properties, and to provide an ultrasonic vibrator, an ultrasonic probe and an ultrasonic medical image diagnosis device using them. <P>SOLUTION: An organic piezoelectric material contains a resin composition having a partial structure represented by formula (UR1), the glass transition temperature being 100 to 180°C. In the formula (UR1), R<SB>1</SB>and R<SB>2</SB>are each independently a hydrogen atom or a substituent, n is an integer of 1 to 3, and R<SB>3</SB>, R<SB>4</SB>, R<SB>7</SB>and R<SB>8</SB>are independently a hydrogen atom, an alkyl group or an aryl group. Further, L<SB>1</SB>is an alkylene group or an arylene group, and L<SB>2</SB>is a mere bonding species, an alkylene oxy group, an arylene group or an aralkylene group. Further, X is an oxygen atom, a sulfur atom or a nitrogen atom, and the nitrogen atom may have a substituent. Furthermore, Y is an oxygen atom or a sulfur atom. The organic piezoelectric material has an electromechanical coupling constant of ≥0.20, and is used for an ultrasonic vibrator for reception by forming electrodes. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic piezoelectric material excellent in piezoelectric characteristics and handleability, an ultrasonic transducer using the same, an ultrasonic probe, and an ultrasonic medical diagnostic imaging apparatus.

  Ultrasonic probes are rapidly used as medical ultrasonic diagnostic apparatuses in addition to nondestructive inspection apparatuses. For example, a probe such as an ultrasonic endoscope radiates a high-frequency acoustic vibration from an ultrasonic transducer into a subject, receives the reflected ultrasonic wave by the ultrasonic transducer, and has a slight interface characteristic. A cross-sectional image inside the living body is obtained by processing different information depending on the difference.

  In recent years, harmonic imaging (Harmonic) that forms an image of the internal state of a subject by its harmonic frequency component, not by the frequency (fundamental frequency) component of the ultrasound transmitted from the ultrasound probe into the subject. Imaging technology is being researched and developed. In this harmonic imaging technique, (1) the side lobe level is smaller than the fundamental frequency component level, the S / N ratio (signal to noise ratio) is improved, and the contrast resolution is improved. Increasing the beam width narrows and the lateral resolution improves. (3) Multiple reflections are suppressed because the sound pressure is small and the fluctuation of the sound pressure is small at a short distance, and (4) It has various advantages such as a greater depth than the case where the attenuation beyond the focal point is the same as that of the fundamental wave and a high frequency is the fundamental wave, and enables highly accurate diagnosis (for example, Patent Document 1). reference).

In such an ultrasonic probe, a piezoelectric body that generates ultrasonic waves is used. Conventionally, as a piezoelectric body, a so-called inorganic material in which a single crystal such as quartz, LiNbO ₃ , LiTaO ₃ , or KNbO ₃ , a thin film such as ZnO or AlN, or a sintered body such as Pb (Zr, Ti) O ₃ is subjected to polarization treatment. Piezoelectric ceramics are widely used.

On the other hand, organic piezoelectric materials (also referred to as “piezoelectric polymer materials” or “polymer piezoelectric materials”) using organic polymer materials such as polyvinylidene fluoride (PVDF) and polyurea have been developed. (For example, refer to Patent Document 2). This organic piezoelectric body has greater flexibility than ceramics piezoelectric bodies, and can be easily made into any shape and form with a thin film, large area, and long length. small, hydrostatic voltage output coefficient (g _h constant) excellent sensitivity characteristics because very becomes larger, it is possible to further lower density, due to low elasticity, efficient energy propagation, having the properties and the like.

  However, in the case of polyurea, the hydrogen bond of the urea group is strong, so the solubility is very poor, and the rigidity is high, so that the handleability is extremely bad. However, there was a fault limited to the vapor deposition polymerization method.

Japanese Patent Laid-Open No. 11-276478 JP-A-6-216422

  The present invention has been made in view of the above-mentioned problems and situations, and a problem to be solved is to provide an organic piezoelectric material excellent in piezoelectric characteristics and handleability. Furthermore, it is to provide an ultrasonic transducer, an ultrasonic probe, and an ultrasonic medical image diagnostic apparatus using them.

  The above-mentioned problem according to the present invention is solved by the following means.

  1. An organic piezoelectric material comprising a resin composition having a partial structure represented by the following general formula (UR1), wherein the resin composition has a glass transition temperature of 100 to 180 ° C. .

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a substituent, and n represents an integer of 1 to _3. R ₃ , R ₄ , R ₇ and R ₈ are each independently a hydrogen atom, alkyl. R ₅ and R ₆ each independently represents a hydrogen atom, an alkyl group or an aryl group, L ₁ represents an alkylene group or an arylene group, L ₂ represents a simple bond type, an alkyleneoxy group, an arylene X represents an oxygen atom, a sulfur atom or a nitrogen atom, the nitrogen atom may have a substituent, and Y represents an oxygen atom or a sulfur atom.)
2. 2. The organic piezoelectric material as described in 1 above, wherein an electromechanical coupling constant of the organic piezoelectric material is 0.20 or more.

  3. 3. The organic piezoelectric material as described in 1 or 2 above, wherein the organic piezoelectric material is subjected to polarization treatment by an electric field or a combination of an electric field and a magnetic field.

  4). An ultrasonic transducer comprising the organic piezoelectric material according to any one of 1 to 3 and an electrode.

  5. 5. An ultrasonic probe comprising the ultrasonic transducer according to 4 above.

  6). 6. The ultrasonic probe according to 5 above, wherein the ultrasonic transducer is a receiving ultrasonic transducer.

  7). An ultrasonic medical image diagnostic apparatus comprising the ultrasonic probe according to 5 or 6 above.

  By the above means of the present invention, an organic piezoelectric material excellent in piezoelectric characteristics and handleability can be provided. Furthermore, an ultrasonic transducer, an ultrasonic probe, and an ultrasonic medical image diagnostic apparatus using them can be provided.

  That is, from the viewpoint of the mechanism of action, it is important for the organic piezoelectric material to have a dipole orientation precisely, which is achieved by polarization treatment. From the viewpoint of an ultrasonic vibrator, stability over time and thermal stability are important, and thermal physical properties of the organic piezoelectric material are important. Since the vibrator generates heat up to 60 to 80 ° C. when driven, it is necessary to guarantee the quality of the material itself even if the material continues to be used at that temperature. By defining the glass transition temperature (Tg) of the piezoelectric material, it is possible to provide a more stable piezoelectric material.

  The lower the Tg, the higher the polarization treatment effect, but it is difficult to maintain the polarization (orientation) because the Tg is low. When the Tg of the material is designed so as to be 100 to 180 ° C. (or a material within this range is selected), a high polarization effect can be obtained and both thermal stability can be achieved.

Conceptual diagram showing the configuration of the main part of an ultrasonic medical diagnostic imaging apparatus

  The organic piezoelectric material of the present invention is an organic piezoelectric material containing a resin composition having a partial structure represented by the general formula (UR1), and the glass transition temperature of the resin composition is 100 to 180 ° C. It is characterized by that. This feature is a technical feature common to the inventions according to claims 1 to 7.

  As an embodiment of the present invention, from the viewpoint of the effect of the present invention, the electromechanical coupling constant of the organic piezoelectric material is preferably 0.20 or more. The organic piezoelectric material is preferably subjected to polarization treatment by an electric field or a combination of an electric field and a magnetic field.

  The organic piezoelectric material of the present invention can be suitably used for an ultrasonic vibrator. Further, the ultrasonic transducer can be suitably used for an ultrasonic probe. In this case, the ultrasonic transducer is preferably a receiving ultrasonic transducer.

  The ultrasonic probe can be suitably used for an ultrasonic medical image diagnostic apparatus.

  Hereinafter, the present invention, its components, and the best mode and mode for carrying out the invention will be described in detail.

(Resin composition constituting organic piezoelectric material)
The organic piezoelectric material of the present invention is an organic piezoelectric material containing a resin composition having a partial structure represented by the general formula (UR1), and the glass transition temperature of the resin composition is 100 to 180 ° C. It is characterized by that.

  Below, the resin composition which comprises the said organic piezoelectric material is demonstrated.

(Partial structure represented by the general formula (UR1))
The organic piezoelectric material of the present invention is a resin-containing composition having a partial structure represented by the general formula (UR1).

As an embodiment of the present invention, in the general formula (UR1), R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. Examples of the substituent include an alkyl group having 1 to 10 carbon atoms ( Methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, etc.), halogen atom (chlorine atom, bromine atom, iodine atom, fluorine atom etc.), alkoxy group (methoxy group) Ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group etc.), aryl group (phenyl group etc.), cyano group, hydroxyl group and the like. A hydrogen atom or an alkyl group is preferable, and a hydrogen atom is more preferable.

  n represents an integer of 1 to 3, and preferably n is 1.

R ₃ , R ₄ , R ₇ and R ₈ each independently represents a hydrogen atom, an alkyl group or an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, and a cyclohexyl group, and examples of the aryl group include a phenyl group, a naphthyl group, and an anthranyl group. Etc. can be mentioned. R ₃ and R 4 may be bonded to each other to form a ring structure. A hydrogen atom or an alkyl group is preferred, a hydrogen atom, a methyl group, an ethyl group or a propyl group is more preferred, and a hydrogen atom, a methyl group or an ethyl group is most preferred.

R ₅ and R ₆ each independently represents a hydrogen atom, an alkyl group or an aryl group. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, and a cyclohexyl group, and examples of the aryl group include a phenyl group, a naphthyl group, and an anthranyl group. Etc. can be mentioned. A hydrogen atom or an alkyl group is preferred, a hydrogen atom, a methyl group, an ethyl group, an isopropyl group or a propyl group is more preferred, and a hydrogen atom, a methyl group or an ethyl group is most preferred.

L ₁ represents an alkylene group or an arylene group. As an alkylene group, a methylene group, ethylene group, n-propylene group, n-butylene group etc. are mentioned, for example. Examples of the arylene group include a phenylene group, a naphthylene group, and a biphenylene group.

L ₂ represents a simple bond type, an arylene group or an aralkylene group. Here, the “simple bond type” means that the left and right bonds of L ₂ in the general formula (UR1) are directly connected.

  Examples of the arylene group include a phenylene group, a naphthylene group, and a biphenylene group. Examples of aralkylene groups include benzylene groups and phenethylene groups.

L ₁ and L ₂ may each independently have a substituent, and examples of the substituent include the substituents exemplified in the above R ₁ and R ₂ .

Preferably, L ₁ is an alkylene group, L ₂ is a simple bond type or an arylene group, and more preferably, L ₁ is an alkylene group and L ₂ is a simple bond type.

X represents an oxygen atom, a sulfur atom or a nitrogen atom, and the nitrogen atom may have a substituent. As a substituent, the substituent quoted by said R < ₁ > and R < ₂ > can be mentioned, Preferably, they are a hydrogen atom or an alkyl group. Y represents an oxygen atom or a sulfur atom.

  The partial structure represented by the general formula (UR1) is obtained by reacting a compound represented by the following general formula (UR2) with a compound represented by the following general formula (UR3), and then reacting a compound or isocyanate having active hydrogen. It can be formed by reacting a compound having a nate group.

(In the formula, R ₁ and R ₂ have the same meanings as R ₁ and R _{2 in the} general formula (UR1). N has the same meaning as n in the general formula (UR1). R ₇ and R ₈ are And R ₇ and R _{8 in} the general formula (UR1), A ₁ represents an isocyanate group, an isothiocyanate group, or an amino group, m represents 0 or 1, and A ₁ represents an isocyanate group. Or, in the case of an isothiocyanate group, m represents 0.)
A ₁ bonded to the carbon atom of the compound represented by the general formula (UR2) may be in any position of the ortho position, the meta position, and the para position. As the compound represented by the general formula (UR2), when A ₁ is an isocyanate group, for example, isocyanatobenzyl isocyanate, isocyanatophenethyl isocyanate, α- (isocyanatophenyl) -ethyl isocyanate, and the like. Can be mentioned. When A1 is an amino group, examples include aminobenzylamine, 2- (4-aminophenyl) ethylamine, and the like, preferably isocyanatobenzyl isocyanate or isocyanatophenethyl isocyanate, and more preferably isocyanato. Natobenzyl isocyanate. When A ₁ is an isothiocyanate group, for example, isothiocyanatobenzyl isocyanate, isothiocyanatophenethyl isocyanate, α- (isothiocyanatophenyl) -ethyl isothiocyanate and the like can be mentioned. When A1 is an amino group, examples thereof include aminobenzylamine, 2- (4-aminophenyl) ethylamine, and the like, preferably isothiocyanatobenzyl isothiocyanate or isothiocyanatophenethyl isothiocyanate, Preferably, isothiocyanatobenzyl isothiocyanate.

(Wherein, _{R 3} and _{R 4,} .L ₁ and _{L 2} have the same meanings as _{R 3} and _{R 4} in the general formula (UR1) is by the _{L 1} and _{L 2} as defined in formula (UR1) R ₅ and R ₆ have the same meanings as R ₅ and R _{6 in} formula (UR1), B ₁ represents an isocyanate group, an isothiocyanate group, or an amino group, and r represents 0 or 1. And when B1 is an isocyanate group or an isothiocyanate group, r represents 0.)
As the compound represented by the general formula (UR3), when B ₁ is an amino group, for example, 1,3-diaminopropane, 1,3-diaminopentane, 2,2-dimethyl-1,3-propanediamine 1,5-diaminopentane, 2-methyl-1,5-diaminopentane, 1,7-diaminoheptane, N, N-bis (3-aminopropyl) methylamine, 1,3-diamino-2-propanol, Examples include diethylene glycol-bis (3-aminopropyl) ether, m-xylylenediamine, 4-aminobenzylamine, 3-aminobenzylamine, 1,3-bis (aminomethyl) cyclohexane, piperazine and the like.

When B ₁ is an isocyanate group, for example, 1,3-bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,3-cyclopentane diisocyanate Etc. When B ₁ is an isothiocyanate group, for example, 1,3-bis (isothiocyanatomethyl) cyclohexane, isophorone diisothiocyanate, trimethylene diisothiocyanate, tetramethylene diisothiocyanate, pentamethylene diisothiocyanate, hexamethylene Examples include diisothiocyanate and 1,3-cyclopentane diisothiocyanate.

  The compound having active hydrogen to be reacted after reacting the compound represented by the general formula (UR2) and the compound represented by the general formula (UR3) has two or more amino groups in the molecule. Examples include polyamines, polyols having two or more hydroxyl groups in the molecule, and amino alcohols.

  Examples of the polyamine include 2,7-diamino-9H-fluorene, 3,6-diaminoacridine, acriflavine, acridine yellow, 2,2- in addition to the diamines listed in the general formulas (UR2) and (UR3). Bis (4-aminophenyl) hexafluoropropane, 4,4'-diaminobenzophenone, bis (4-aminophenyl) sulfone, 4,4'-diaminodiphenyl ether, bis (4-aminophenyl) sulfide, 1,1-bis (4-aminophenyl) cyclohexane, 4,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 3,3'-diaminobenzophenone, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4- ( Phenyldiazenyl) benzene-1,3-diamine, 1,5-dia Bruno naphthalene, 1,3-phenylenediamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 1,8-diaminonaphthalene and the like.

  Polyols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol In order not to lower the piezoelectric characteristics, a polyol having a total carbon number of 10 or less is preferable.

  Examples of amino alcohol include aminoethanol, 3-amino-1-propanol, 2- (2-aminoethoxy) ethanol, 2-amino-1,3-propanediol, and 2-amino-2-methyl-1,3. -Propanediol, 1,3-diamino-2-propanol, etc. can be mentioned.

  The compound having an isocyanate group to be reacted after reacting the compound represented by the general formula (UR2) and the compound represented by the general formula (UR3) includes two isocyanate groups in the molecule. The polyisocyanate which has the above is mentioned.

  Examples of the polyisocyanate include 9H-fluorene-2,7-diisocyanate and 9H-fluoren-9-one-2,7-diisocyanate in addition to the diisocyanates listed in the general formulas (UR2) and (UR3). 4,4'-diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 1,3-bis (isocyanatomethyl) ) Cyclohexane, 2,2-bis (4-isocyanatophenyl) hexafluoropropane, 1,5-diisocyanatonaphthalene and the like.

  Hereinafter, although the preferable specific example of the partial structure represented by the said general formula (UR1) is given, this invention is not limited to this.

(Method for producing a resin-containing composition having a partial structure represented by the general formula (UR1))
The resin-containing composition according to the present invention is characterized by being a resin having a partial structure represented by the general formula (UR1). In addition to the resin, the composition contains a raw material, You may contain the additive etc. for providing a special function.

  Hereinafter, the manufacturing method of the composition which does not contain a special additive is demonstrated.

  The resin-containing composition having a partial structure represented by the general formula (UR1) is activated after reacting the compound represented by the general formula (UR2) with the compound represented by the general formula (UR3). It is obtained by reacting a compound having hydrogen.

  In the case where the compound represented by the general formula (UR3) and the compound having active hydrogen are the same, there is no limitation in the order of addition of the starting monomer, and the general formula is compared with the compound represented by the general formula (UR2). A compound represented by (UR3) may be added, or the order of addition may be reversed. The amount of the general formula (UR3) used relative to the general formula (UR2) is preferably 0.8 to 1.2 times mol, more preferably 0.9 to 1.1 times mol, and particularly preferably 1. 0 times mole.

  When the compound represented by the general formula (UR3) is different from the compound having active hydrogen, the compound represented by the general formula (UR3) is added to the compound represented by the general formula (UR2). The compound having active hydrogen may be added, and the compound represented by the general formula (UR3) and the compound having active hydrogen are mixed and added to the compound represented by the general formula (UR2). Also good. The amount of the general formula (UR3) used relative to the general formula (UR2) is preferably 0.4 to 0.6 times mol, more preferably 0.45 to 0.55 times mol, and particularly preferably 0.8. It is 49-0.51 times mole. The amount of the compound having active hydrogen with respect to the general formula (UR2) is preferably 0.4 to 0.6 times mol, more preferably 0.45 to 0.55 times mol, particularly preferably 0.49. -0.51 times mole.

  When the compound represented by the general formula (UR3) and the compound having active hydrogen are the same, the reaction temperature is not limited, but is preferably 0 ° C to 100 ° C, more preferably 10 ° C to 80 ° C. More preferably, it is 20 degreeC-70 degreeC.

  When the compound represented by the general formula (UR3) is different from the compound having active hydrogen, the reaction temperature is preferably -40 to 60 ° C, more preferably -20 to 30 ° C, and particularly preferably -10 to 10 ° C. 10 ° C. Further, after the addition of the compound having active hydrogen is completed, the reaction may be continued at a constant temperature, or the reaction may be completed by raising the temperature.

  As the solvent used for the reaction, it is necessary to use a highly polar solvent in order that the target resin composition is highly polar and the polymerization proceeds efficiently. For example, it is preferable to select a highly polar aprotic solvent such as DMF (N, N-dimethylformamide), DMAc (N, N-dimethylacetamide), DMSO (dimethylsulfoxide), NMP (N-methylpyrrolidone), As long as the reaction substrate and target compound dissolve well, aliphatic hydrocarbons such as cyclohexane, pentane and hexane, aromatic hydrocarbons such as benzene, toluene and chlorobenzene, THF (tetrahydrofuran), diethyl ether, ethylene glycol diethyl It may be a solvent such as ethers such as ether, ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, esters such as methyl propionate, ethyl acetate, butyl acetate, etc. May be.

  When the terminal group of the compound having active hydrogen is a hydroxyl group, in order to efficiently promote urethane bond formation, three compounds such as N, N, N ′, N′-tetramethyl-1,3-butanediamine, triethylamine, and tributylamine are used. Secondary alkylamines, condensed ring amines such as 1,4-diazabicyclo [2.2.2] octane, 1,8-diazabicyclo [5.4.0] unde-7-ene, DBTL, tetrabutyltin, tributyltinacetic acid A well-known urethane bond production | generation catalyst, such as alkyl tins, such as ester, can be used.

  The amount of the catalyst used is preferably 0.1 to 30 mol% based on the monomer substrate in consideration of efficient reaction and reaction operation.

  The polymerized resin composition is preferably purified by reprecipitation.

  The method for reprecipitation of the resin composition is not particularly limited, but a method in which the resin composition is dissolved in a good solvent and then dropped into a poor solvent for precipitation is preferable.

  As used herein, the “good solvent” may be any solvent as long as it dissolves the resin composition, but is preferably a polar solvent, specifically, DMF (N, N-dimethylformamide), Examples thereof include highly polar aprotic solvents such as DMAc (N, N-dimethylacetamide), DMSO (dimethylsulfoxide), and NMP (N-methylpyrrolidone).

  The “poor solvent” may be any solvent as long as it does not dissolve the resin composition, but is an aliphatic hydrocarbon such as cyclohexane, pentane or hexane, or an aromatic carbon such as benzene, toluene or chlorobenzene. Examples include hydrogens, ethers such as diethyl ether and ethylene glycol diethyl ether, esters such as methyl propionate, ethyl acetate and butyl acetate, and alcohols such as methanol, ethanol and propanol.

(Control of glass transition temperature)
The glass transition temperature (Tg) can be controlled to some extent by changing the unit structure of the polymer. When Tg is 180 ° C. or higher, a urethane bond is added, hydrogen in the urea bond is replaced with another group (for example, an alkyl group), an oxyalkylene group is introduced into the molecular chain constituting the main chain, etc. Can be lowered. On the other hand, when the temperature is 100 ° C. or lower, Tg can be increased by adding a urea bond, eliminating a substituent in the urea bond, or increasing the ratio of the aromatic structure.

(Organic piezoelectric material)
The organic piezoelectric material of the present invention can be obtained by forming a film using a resin composition containing the formed resin, or by subjecting the resin composition film to further polarization treatment. Can be formed.

  In the organic piezoelectric film, when a stress is applied to the piezoelectric film, charges of opposite signs appear in proportion to both ends of the piezoelectric film, that is, an electric polarization phenomenon occurs, and conversely, the piezoelectric material is transmitted. It has the property (piezoelectric performance) that a distortion proportional to the occurrence of the electric field (applying an electric field) is generated. In particular, in the organic piezoelectric film made of the organic piezoelectric material of the present invention, a large piezoelectric effect is generated by polarization due to orientation freezing of the dipole moment of the polymer main chain or side chain.

  On the other hand, when energy (heat) is applied to the piezoelectric film, the magnitude of spontaneous polarization in the piezoelectric film changes accordingly. At this time, the surface charge existing on the surface of the piezoelectric film so as to neutralize the spontaneous polarization cannot respond to the energy change as quickly as the spontaneous polarization. There is a charge corresponding to the change in spontaneous polarization. The generation of electricity associated with this energy change is called pyroelectricity. In particular, in the organic piezoelectric film made of the organic piezoelectric material of the present invention, polarization due to orientation freezing of the dipole moment of the main chain or side chain of the polymer Results in greater pyroelectric performance.

(Method of forming organic piezoelectric film)
The organic piezoelectric film is preferably formed by coating. Examples of the coating method include spin coating, solvent casting, melt casting, roll coating, flow coating, printing, dip coating, and bar coating.

  An adjustment method for using an electromechanical coupling constant of 0.2 or more is to prepare a film from an organic piezoelectric material containing the resin composition, and the film is stretched, annealed, polarized, etc. It is obtained by applying. Annealing treatment and polarization treatment may be used in combination.

  In the case of a stretching process, it is desirable to stretch 2 to 5 times. Although the temperature at the time of stretching depends on the physical properties of the organic piezoelectric material, stretching at 20 to 150 ° C is preferable, and 40 to 120 ° C is more preferable.

  In the case of the annealing treatment, if the organic piezoelectric material is a material exhibiting ferroelectricity, it is necessary to carry out at a temperature equal to or lower than the Curie temperature. On the other hand, if the material does not exhibit ferroelectricity, it is necessary to carry out at a melting point or lower.

(Organic piezoelectric film)
The organic piezoelectric film according to the present invention can be produced using the above piezoelectric material by various conventionally known methods such as a melting method and a casting method.

  In the present invention, as a method for producing an organic piezoelectric film, basically, a method of applying a solution of the above polymer material or the like on a substrate and drying it, or using a raw material compound of the above polymer material has been conventionally used. A method of forming a polymer film by a known solution polymerization coating method or the like can be employed.

  Specific methods and conditions of the solution polymerization coating method can be carried out according to various conventionally known methods. For example, a method of forming an organic piezoelectric film by applying a mixed solution of raw materials on a substrate, drying to some extent under reduced pressure conditions (after removing the solvent), heating, thermal polymerization, and then or simultaneously performing polarization treatment Is preferred.

  In order to improve the piezoelectric characteristics, it is useful to add a process for aligning the molecular arrangement. Examples of means include stretching film formation and polarization treatment.

  Various known methods can be adopted for the method of stretching film formation. For example, a solution in which the above organic polymer material is dissolved in an organic solvent such as ethyl methyl ketone (MEK) is cast on a substrate such as a glass plate, and the solvent is dried at room temperature to obtain a film having a desired thickness. Then, the film is stretched to a predetermined length at room temperature. The stretching can be performed in a uniaxial or biaxial direction so that the organic piezoelectric film having a predetermined shape is not broken. The draw ratio is 2 to 10 times, preferably 2 to 6 times.

(Polarization treatment)
As a polarization treatment method in the polarization treatment according to the present invention, a conventionally known method such as DC voltage application treatment, AC voltage application treatment, or corona discharge treatment can be applied.

  For example, in the case of the corona discharge treatment method, the corona discharge treatment can be performed by using a commercially available device comprising a high voltage power source and electrodes.

  Since the discharge conditions vary depending on the equipment and the processing environment, it is preferable to select the conditions as appropriate. The voltage of the high voltage power source is preferably -1 to -20 kV, the current is 1 to 80 mA, the distance between the electrodes is preferably 1 to 10 cm, and the applied voltage is preferably 0.5 to 2.0 MV / m. .

  As the electrodes, needle-like electrodes, linear electrodes (wire electrodes), and mesh-like electrodes that have been conventionally used are preferable, but the invention is not limited thereto.

  In the case where the organic piezoelectric material of the present invention is subjected to polarization treatment by corona discharge, a planar electrode is disposed so as to be in contact with the first surface of the organic piezoelectric material, and the second electrode is opposed to the first surface. It is preferable that a columnar corona discharge electrode is installed on the surface side of the electrode and the polarization treatment is performed by corona discharge.

  The polarization treatment prevents the oxidation of the surface of the material due to water and oxygen and does not impair the piezoelectricity. For this reason, the absolute mass humidity is 0.004 or less in a nitrogen or rare gas (helium, argon, etc.) stream. The embodiment applied in the environment is preferred. A nitrogen stream is particularly preferable.

  In addition, at least one of an organic piezoelectric material including a planar electrode placed in contact with the first surface or a cylindrical corona discharge electrode provided on the second surface side moves at a constant speed. However, corona discharge is preferably performed.

In the present application, “mass absolute humidity” means that when the mass of water vapor contained in the humid air is m _w [kg] with respect to the mass m _DA [kg] of dry air, The ratio SH (Specific humidity) defined by is expressed in [kg / kg (DA)] (DA is an abbreviation of dry air). However, in the present application, the unit is omitted.

(Formula): SH = m _w / m _DA [kg / kg (DA)]
Here, air containing water vapor is referred to as “wet air”, and air obtained by removing water vapor from the humid air is referred to as “dry air”.

In addition, the definition of mass absolute humidity under nitrogen or rare gas (helium, argon, etc.) airflow is the same as the case of the above-mentioned air, and the moisture vapor contained in the wet gas with respect to the dry gas mass m _DG [kg]. When the mass is m _w [kg], it means the ratio SH defined according to the above formula, and the unit is represented by [kg / kg (DG)] (DG is an abbreviation for dry gas). However, in the present application, the unit is omitted.

  In addition, “installation” means that an existing electrode separately prepared in advance is placed so as to be in contact with the surface of the organic piezoelectric material, or the electrode constituent material is attached to the surface of the organic piezoelectric material by a vapor deposition method or the like. It refers to forming an electrode above.

  In addition, it is preferable that the organic piezoelectric film formed of the organic piezoelectric material of the present invention is formed in an electric field in the formation process, that is, a polarization treatment is performed in the formation process. At this time, a magnetic field may be used in combination.

  In the corona discharge treatment method according to the present invention, the treatment can be performed using a commercially available apparatus comprising a high voltage power source and electrodes.

  Since the discharge conditions vary depending on the equipment and processing environment, it is preferable to select the conditions as appropriate. However, the voltage of the high voltage power supply is 1 to 20 kV for both positive and negative voltages, 1 to 80 mA for the current, and the distance between the electrodes. 0.5-10 cm is preferable, and the applied electric field is preferably 0.5-2.0 MV / m. The organic piezoelectric material or the organic piezoelectric film during the polarization treatment is preferably 50 to 250 ° C, more preferably 70 to 180 ° C.

  As an electrode used for corona discharge, it is necessary to use a columnar electrode as described above in order to perform a polarization treatment uniformly.

  In addition, in this application, it is preferable that the diameter of the circle | round | yen of a cylindrical electrode is 0.1 mm-2 cm. The length of the cylinder is preferably set to an appropriate length according to the size of the organic piezoelectric material to be polarized. For example, in general, the thickness is preferably 5 cm or less from the viewpoint of uniformly performing the polarization treatment.

  These electrodes are preferably stretched at a portion where corona discharge is performed, and can be realized by a method of applying a constant weight to both ends of the electrodes or fixing the electrodes in a state where a constant weight is applied. Moreover, as a constituent material of these electrodes, a general metal material can be used, but gold, silver and copper are particularly preferable.

  In order to perform a uniform polarization process, it is preferable that the planar electrode placed so as to be in contact with the first surface is in close contact with the organic piezoelectric material. That is, it is preferable to perform corona discharge after forming an organic polymer film or an organic piezoelectric film on a substrate provided with a planar electrode.

  In addition, as a manufacturing method of the ultrasonic transducer | vibrator which concerns on this invention, before the formation of the electrode installed in both surfaces of an organic piezoelectric (body) film | membrane, a polarization process is carried out either after an electrode formation on one side or after an electrode formation on both sides It is preferable that it is the manufacturing method of the aspect to do. Moreover, it is preferable that the said polarization process is a voltage application process.

  In the present invention, it is preferable that the organic piezoelectric material is subjected to polarization treatment by an electric field or a combination of an electric field and a magnetic field as described above.

(substrate)
As the substrate, the selection of the substrate varies depending on the use and usage of the organic piezoelectric film according to the present invention. In the present invention, a plastic plate or film such as polyimide, polyamide, polyimide amide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate resin, or cycloolefin polymer is used. Can do. Further, the surface of these materials may be covered with aluminum, gold, copper, magnesium, silicon or the like. A single crystal plate or film of aluminum, gold, copper, magnesium, silicon alone, or a rare earth halide may also be used. The substrate itself may not be used.

(Ultrasonic transducer)
The ultrasonic transducer according to the present invention is characterized by using an organic piezoelectric film formed using the organic piezoelectric material of the present invention. The ultrasonic transducer is preferably an ultrasonic receiving transducer used in an ultrasonic medical diagnostic imaging device probe including an ultrasonic transmitting transducer and an ultrasonic transmitting transducer. .

  In general, an ultrasonic vibrator has a pair of electrodes sandwiched between layers (or films) made of a film-like piezoelectric material (also referred to as “piezoelectric film”, “piezoelectric film”, or “piezoelectric layer”). An ultrasonic probe is configured by arranging a plurality of transducers, for example, one-dimensionally.

  Then, a predetermined number of transducers in the major axis direction in which a plurality of transducers are arranged is set as the aperture, and the plurality of transducers belonging to the aperture are driven to focus the ultrasonic beam on the measurement site in the subject. And has a function of receiving reflected echoes of ultrasonic waves emitted from the subject by a plurality of transducers belonging to the aperture and converting them into electrical signals.

  Hereinafter, each of the ultrasonic wave receiving transducer and the ultrasonic wave transmitting transducer according to the present invention will be described in detail.

<Ultrasound receiving transducer>
An ultrasonic receiving vibrator according to the present invention is a vibrator having an ultrasonic receiving piezoelectric material used for a probe for an ultrasonic medical diagnostic imaging apparatus, and the piezoelectric material constituting the ultrasonic receiving vibrator is an element of the present invention. An embodiment using an organic piezoelectric film formed using an organic piezoelectric material is preferable.

The organic piezoelectric material or the organic piezoelectric film used for the ultrasonic receiving vibrator preferably has a relative dielectric constant of 10 to 50 at the thickness resonance frequency. The relative dielectric constant is adjusted by adjusting the number, composition, degree of polymerization, etc. of the polar functional groups such as the substituent R, CF ₂ group, and CN group of the compound constituting the organic piezoelectric material, and the polarization treatment described above. Can be done by.

  The organic piezoelectric film constituting the receiving vibrator of the present invention can also be configured by laminating a plurality of polymer materials. In this case, as the polymer material to be laminated, the following polymer material having a relatively low relative dielectric constant can be used in addition to the above polymer material.

  In the following examples, the numerical values in parentheses indicate the relative dielectric constant of the polymer material (resin).

  For example, methyl methacrylate resin (3.0), acrylonitrile resin (4.0), acetate resin (3.4), aniline resin (3.5), aniline formaldehyde resin (4.0), aminoalkyl resin ( 4.0), alkyd resin (5.0), nylon-6-6 (3.4), ethylene resin (2.2), epoxy resin (2.5), vinyl chloride resin (3.3), chloride Vinylidene resin (3.0), urea formaldehyde resin (7.0), polyacetal resin (3.6), polyurethane (5.0), polyester resin (2.8), polyethylene (low pressure) (2.3), Polyethylene terephthalate (2.9), polycarbonate resin (2.9), melamine resin (5.1), melamine formaldehyde resin (8.0), cellulose acetate (3.2), acetic acid Sulfonyl resin (2.7), styrene resins (2.3), styrene-butadiene rubber (3.0), styrene resin (2.4), it can be used polytetrafluoroethylene (2.0) or the like.

  The polymer material having a low relative dielectric constant is preferably selected in accordance with various purposes such as adjusting the piezoelectric characteristics or imparting the physical strength of the organic piezoelectric film. .

<Transmitter for ultrasonic transmission>
The ultrasonic transmission vibrator according to the present invention is preferably made of a piezoelectric material having an appropriate relative dielectric constant in relation to the vibrator having the receiving piezoelectric material. Moreover, it is preferable to use a piezoelectric material excellent in heat resistance and voltage resistance.

  Various known organic piezoelectric materials and inorganic piezoelectric materials can be used as the ultrasonic transmitting vibrator constituent material.

  As the organic piezoelectric material, a polymer material similar to the above-described organic piezoelectric material for constituting an ultrasonic receiving vibrator can be used.

Inorganic materials include quartz, lithium niobate (LiNbO ₃ ), potassium tantalate niobate [K (Ta, Nb) O ₃ ], barium titanate (BaTiO ₃ ), lithium tantalate (LiTaO ₃ ), or titanate Lead zirconate (PZT), strontium titanate (SrTiO ₃ ), barium strontium titanate (BST), or the like can be used. PZT is preferably Pb (Zr _1-n Ti _n ) O ₃ (0.47 ≦ n ≦ 1).

<electrode>
The piezoelectric (body) vibrator according to the present invention is manufactured by forming electrodes on both surfaces or one surface of a piezoelectric film (layer) and polarizing the piezoelectric film. When producing an ultrasonic wave receiving vibrator using an organic piezoelectric material, the electrode on the first surface used for the polarization treatment may be used as it is. The electrode is formed using an electrode material mainly composed of gold (Au), platinum (Pt), silver (Ag), palladium (Pd), copper (Cu), nickel (Ni), tin (Sn), or the like. .

  In forming the electrodes, first, a base metal such as titanium (Ti) or chromium (Cr) is formed to a thickness of 0.02 to 1.0 μm by sputtering, and then the metal mainly composed of the above metal elements and those A metal material made of the above alloy, and further, if necessary, a part of the insulating material is formed to a thickness of 1 to 10 μm by sputtering, vapor deposition or other suitable methods. In addition to sputtering, these electrodes can be formed by screen printing, dipping, or thermal spraying using a conductive paste in which fine metal powder and low-melting glass are mixed.

  Furthermore, a piezoelectric element is obtained by supplying a predetermined voltage between the electrodes formed on both surfaces of the piezoelectric film to polarize the piezoelectric film.

(Ultrasonic probe)
The ultrasonic probe according to the present invention is a main component of an ultrasonic diagnostic imaging apparatus and has a function of generating ultrasonic waves and transmitting / receiving ultrasonic beams. The internal configuration of the ultrasonic probe may take various forms, but as a general configuration, from the tip (surface contacting the living body that is the subject), the “acoustic lens”, “acoustic matching layer”, A configuration of an aspect in which “ultrasonic transducer (element)” and “backing” are juxtaposed in this order may be employed.

  An ultrasonic probe according to the present invention is a probe for an ultrasonic medical image diagnostic apparatus including an ultrasonic transmission transducer and an ultrasonic reception transducer. The ultrasonic receiving transducer according to the invention is used.

  In the present invention, both transmission and reception of ultrasonic waves may be performed by a single transducer, but more preferably, the transducers are configured separately for transmission and reception in the probe.

  The piezoelectric material constituting the transmitting vibrator may be a conventionally known ceramic inorganic piezoelectric material or an organic piezoelectric material.

  In the ultrasonic probe according to the present invention, the ultrasonic receiving transducer of the present invention can be arranged on or in parallel with the transmitting transducer.

  As a more preferred embodiment, the structure for laminating the ultrasonic receiving transducer of the present invention on the ultrasonic transmitting transducer is good, and in this case, the ultrasonic receiving transducer of the present invention is another high-frequency transducer. You may laminate | stack on the vibrator | oscillator for transmission in the form joined together on the molecular material (The polymer (resin) film, for example, polyester film) whose relative dielectric constant is comparatively low as a support body. In this case, it is preferable that the film thickness of the receiving vibrator and the other polymer material be matched to a preferable receiving frequency band in terms of probe design. Considering a practical ultrasonic medical diagnostic imaging apparatus and biological information collection from a practical frequency band, the film thickness is preferably 40 to 150 μm.

  The probe may be provided with a backing layer, an acoustic matching layer, an acoustic lens, and the like. Also, a probe in which vibrators having a large number of piezoelectric materials are two-dimensionally arranged can be used. A plurality of two-dimensionally arranged probes can be sequentially scanned to form a scanner.

(Acoustic lens)
The acoustic lens according to the present invention is arranged to focus an ultrasonic beam using refraction and improve resolution. The present invention is characterized in that a substance that emits light when irradiated with excitation light, that is, a luminescent substance is added to a region near the subject surface of the acoustic lens.

The acoustic lens converges the ultrasonic wave and is in close contact with the living body to match the acoustic impedance of the living body (density × sound speed; (1.4 to 1.6) × 10 ⁶ kg / m ² · sec), It is a necessary condition that the reflection of ultrasonic waves can be reduced and that the ultrasonic attenuation amount of the lens itself is small.

  That is, an acoustic lens conventionally made of a polymer material such as rubber or the like is provided at a portion in contact with the human body to focus the ultrasonic beam. As the lens material used here, it is desirable that the sound velocity is sufficiently smaller than that of the human body, the attenuation is small, and the acoustic impedance is close to the value of the human skin. If the lens material has a sound velocity sufficiently smaller than that of the human body, the lens shape can be made convex, and slipping can be performed safely when making a diagnosis, and if the attenuation is reduced, sensitivity is improved. If the ultrasonic impedance can be transmitted and received and the acoustic impedance is close to the value of the skin of the human body, the reflection will be small, in other words, the transmittance will be large. Because.

  In the present invention, the material constituting the acoustic lens includes conventionally known homopolymers such as silicon rubber, fluorine silicon rubber, polyurethane rubber, epichlorohydrin rubber, and ethylene-propylene copolymer rubber obtained by copolymerizing ethylene and propylene. Copolymer rubber etc. can be used. Of these, it is preferable to use silicon rubber.

  Examples of the silicon rubber used in the present invention include silicon rubber and fluorine silicon rubber. In particular, it is preferable to use silicon rubber because of the characteristics of the lens material. Silicon rubber is an organopolysiloxane having a molecular skeleton composed of Si—O bonds, and having a plurality of organic groups bonded to Si atoms. Usually, the main component is methylpolysiloxane, and the entire organic structure is organic. 90% or more of the groups are methyl groups. A material in which a hydrogen atom, a phenyl group, a vinyl group, an allyl group or the like is introduced instead of the methyl group can also be used. The silicone rubber can be obtained, for example, by kneading a curing agent (vulcanizing agent) such as benzoyl peroxide in an organopolysiloxane having a high polymerization degree, followed by heat vulcanization and curing. If necessary, organic or inorganic fillers such as silica and nylon powder, and vulcanization aids such as sulfur and zinc oxide may be added.

  Examples of the butadiene rubber used in the present invention include butadiene alone or a copolymer rubber mainly composed of butadiene and copolymerized with a small amount of styrene or acrylonitrile. In particular, it is preferable to use butadiene rubber because of the characteristics of the lens material. The butadiene rubber refers to a synthetic rubber obtained by polymerization of butadiene having a conjugated double bond. Butadiene rubber can be obtained by 1,4 or 1.2 polymerization of butadiene alone having a conjugated double bond. A butadiene rubber vulcanized with sulfur or the like can be used.

  The acoustic lens according to the present invention can be obtained by mixing silicon rubber and butadiene rubber and curing them. For example, it can be obtained by mixing silicon rubber and butadiene rubber in an appropriate ratio by a kneading roll, adding a vulcanizing agent such as benzoyl peroxide, and heat vulcanizing and crosslinking (curing). At that time, it is preferable to add zinc oxide as a vulcanization aid. Zinc oxide can accelerate vulcanization and shorten the vulcanization time without deteriorating lens characteristics. In addition, other additives may be added as long as the characteristics of the colorant and the acoustic lens are not impaired. The mixing ratio of the silicone rubber and the butadiene rubber is preferably 1: 1 in order to obtain a material whose acoustic impedance is close to that of the human body and whose sound speed is smaller than that of the human body and less attenuated. The mixing ratio can be changed as appropriate.

  In the present invention, an inorganic filler such as silica, alumina, titanium oxide, nylon, etc., depending on the purpose of adjusting the speed of sound, adjusting the density, etc., based on the rubber material such as silicon rubber (main component). An organic resin or the like can also be blended.

(Backing layer)
In the present invention, it is also preferable that a backing layer is provided on the back surface of the ultrasonic transducer for the purpose of suppressing propagation of ultrasonic waves to the rear. Thereby, the pulse width can be shortened.

(Acoustic matching layer)
The acoustic matching layer (also referred to as “λ / 4 layer”) is arranged in multiple layers in order to reduce the difference in acoustic impedance between the transducer and the living body and efficiently transmit and receive ultrasonic waves.

(Ultrasonic medical diagnostic imaging equipment)
The ultrasonic probe according to the present invention can be used for various types of ultrasonic diagnostic apparatuses. FIG. 1 is a conceptual diagram showing the configuration of the main part of an ultrasonic medical image diagnostic apparatus according to an embodiment of the present invention.

  This ultrasonic medical diagnostic imaging apparatus transmits an ultrasonic wave to a subject such as a patient, and an ultrasonic probe in which piezoelectric vibrators that receive ultrasonic waves reflected by the subject as echo signals are arranged. (Probe). In addition, an electric signal is supplied to the ultrasonic probe to generate an ultrasonic wave, and a transmission / reception circuit that receives an echo signal received by each piezoelectric vibrator of the ultrasonic probe, and transmission / reception control of the transmission / reception circuit A transmission / reception control circuit is provided.

  Furthermore, an image data conversion circuit that converts echo signals received by the transmission / reception circuit into ultrasonic image data of the subject is provided. Further, a display control circuit for controlling and displaying the monitor with the ultrasonic image data converted by the image data conversion circuit and a control circuit for controlling the entire ultrasonic medical image diagnostic apparatus are provided.

  A transmission / reception control circuit, an image data conversion circuit, and a display control circuit are connected to the control circuit, and the control circuit controls operations of these units. Then, an electrical signal is applied to each piezoelectric vibrator of the ultrasonic probe to transmit an ultrasonic wave to the subject, and the reflected wave caused by acoustic impedance mismatch inside the subject is detected by the ultrasonic probe. Receive at.

  The transmission / reception circuit corresponds to “means for generating an electrical signal”, and the image data conversion circuit corresponds to “image processing means”.

  According to the ultrasonic diagnostic apparatus as described above, by utilizing the characteristics of the ultrasonic receiving vibrator excellent in piezoelectric characteristics and heat resistance of the present invention and suitable for high frequency and wide band, the image quality and its An ultrasonic image with improved reproduction and stability can be obtained.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to these.

Example 1 Production of Resin Composition and Resin Composition Film <Polymerization Method A>
The compounds represented by the general formula (UR2) (described in Tables 1 and 2) were dissolved in DMF and cooled to 0 ° C. A compound represented by the general formula (UR2) and an equimolar amount of the compound represented by the general formula (UR3) (described in Table 1 and Table 2) were dissolved in DMF and added. After stirring at 0 ° C. for 1 hour, compounds having active hydrogen (described in Tables 1 and 2) were added by dissolving in DMF, heated to 30 ° C. and stirred for 24 hours. Furthermore, the reaction solution is heated to 80 ° C., stirred for 8 hours, concentrated under reduced pressure until the amount of the reaction solution is halved, reprecipitated with methanol, and dried under reduced pressure at 70 ° C. Thus, the intended resin composition was obtained.

<Polymerization method B>
The compounds represented by the general formula (UR2) (described in Tables 1 and 2) were dissolved in DMF and cooled to 0 ° C. A compound represented by the general formula (UR2) and an equimolar amount of the compound represented by the general formula (UR3) (described in Table 1 and Table 2) were dissolved in DMF and added. After stirring at 0 ° C. for 1 hour, compounds having active hydrogen (described in Tables 1 and 2) were added by dissolving in DMF, followed by addition of 0.1 g of DBTL. The reaction solution was heated to 30 ° C. and stirred for 24 hours, and then concentrated under reduced pressure until the amount of the reaction solution was halved and reprecipitated with methanol. After filtration, the intended resin composition was obtained by drying under reduced pressure at 70 ° C.

<Polymerization method C>
The compounds represented by the general formula (UR2) (described in Tables 1 and 2) were dissolved in DMF and cooled to 0 ° C. Two times moles of the compound represented by the general formula (UR3) (described in Table 1 and Table 2) with respect to the compound represented by the general formula (UR2) were dissolved in DMF and added. After stirring at 0 ° C. for 1 hour, the temperature was raised to 30 ° C. and stirring was performed for 24 hours. Under reduced pressure conditions, the reaction solution was concentrated until the liquid volume was reduced to half, reprecipitated with methanol, and then dried under reduced pressure at 70 ° C. to obtain the intended resin composition.

  The weight average molecular weight and molecular weight distribution of the resin composition were measured by GPC and determined in terms of polystyrene.

  In this example, the weight average molecular weight (Mn) and the molecular weight distribution (Mw / Mn) were calculated by gel permeation chromatography (GPC) in the following manner. The measurement conditions are as follows.

Solvent: 30 mM LiBr in N-methylpyrrolidone Device: HLC-8220GPC (manufactured by Tosoh Corporation)
Column: TSKgel SuperAWM-H x 2 (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Sample concentration: 1.0 g / L
Injection volume: 40 μl
Flow rate: 0.5 ml / min
Calibration curve: Standard polystyrene: PS-1 (manufactured by Polymer Laboratories) Mw = 580 to 2,560,000 calibration curves with 9 samples were used.

<Preparation of resin composition film>
These obtained resin compositions were applied and dried on a 25 μm polyimide film which had been pre-deposited on the surface with a 1% methanol solution of polyvinyl alcohol having a polymerization degree of 500 so that the dry film pressure would be 0.1 μm. Coating and drying were performed on the substrate so that the dry film pressure was 7 μm. Next, after an aluminum electrode is attached by vapor deposition to the surface of the substrate on which the film of the resin composition is thus formed, 100MV is used by using a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.). In a state where an electric field of / m is applied, the temperature rises at a rate of 5 ° C./min to the temperature of Tg + 20 ° C. evaluated below, and after holding for 15 minutes, gradually cools to room temperature while applying the voltage, and performs a polling treatment. Application resin composition films -1 to 15 were produced. In addition, since the said resin composition film | membrane is equipped with the electrode, it can be used with an ultrasonic transducer | vibrator.

Comparative Example 1 Preparation of Comparative Resin Composition and Comparative Resin Composition Film 0.87 g of p-isocyanatobenzyl isocyanate was dissolved in 10 ml of DMF and cooled to 0 ° C. A solution prepared by dissolving 1.30 g of 2,2-bis (4- (4-aminophenoxy) phenyl) hexafluoropropane and 0.16 g of ethylene glycol in 10 ml of DMF was added in one pot and stirred for 1 hour. DBTL 0.1g was added to the reaction liquid, and it heated up at 30 degreeC, and stirred for 24 hours. Under reduced pressure conditions, the reaction solution was concentrated until the liquid volume became half, reprecipitated with methanol, and then dried under reduced pressure at 70 ° C. to obtain 2.2 g of a comparative resin composition (1).

  The obtained resin composition was applied and dried on a 25 μm polyimide film that had been pre-deposited on the surface with a methanol solution of polyvinyl alcohol having a polymerization degree of 1% of 500% so that the dry film pressure was 0.1 μm. On the substrate, coating and drying were performed so that the dry film pressure was 7 μm. Next, after an aluminum electrode is attached by vapor deposition to the surface of the substrate on which the film of the resin composition is thus formed, 100MV is used by using a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.). In a state where an electric field of / m is applied, the temperature rises at a rate of 5 ° C./min to the temperature of Tg + 20 ° C. evaluated below, and after holding for 15 minutes, gradually cools to room temperature while applying the voltage, and performs a polling treatment. Application comparative resin composition film-1 was prepared.

(Comparative Example 2) Production of Comparative Resin Composition Film The aforementioned polyimide substrate was mounted in a vacuum processing chamber, and 4,4'-diaminodiphenylmethane was filled in one of the evaporation containers and 4,4'-diphenylmethane diisocyanate was filled in the other, respectively. Then, with the shutter closed, the total pressure in the processing chamber was set to 1.33 × 10 ⁻¹ Pa (1 × 10 ⁻³ Torr) by a vacuum exhaust system. 4,4′-diphenylmethane diisocyanate was heated to a temperature of 70 ± 2 ° C. and 4,4′-diaminodiphenylmethane was heated to a temperature of 110 ± 2 ° C., and vapor deposition polymerization was performed on a polyimide substrate, and vapor deposition was performed to 7 μm. In this way, the substrate on which the polyurea film is formed is taken out, and while applying a voltage to 0.2 MV / m using a high voltage power supply device HARB-20R60 (manufactured by Matsusada Precision Co., Ltd.) and a needle electrode, The temperature was raised at a rate of 5 ° C./min to a temperature of 180 ° C. evaluated below, and after maintaining for 15 minutes, it was gradually cooled to room temperature while the voltage was applied to prepare Comparative Resin Composition Film-2.

(Example 2)
The obtained various resin composition films were used as ultrasonic vibrators, and the piezoelectricity was evaluated by a resonance method in a state of heating to room temperature and 100 ° C. In addition, a piezoelectric characteristic is shown as a relative value with the value when measured at room temperature of the PVDF film as 100%.

Example 3
Of the obtained resin composition films, a part of the resin composition film is cut into 2 cm squares, and the pyroelectric property is set in a temperature bath whose temperature is variable from −100 degrees Celsius to 150 degrees Celsius, and the rate of temperature rise The pyroelectric rate was measured by observing the generated electric charge with a microammeter. The pyroelectric rate is shown as a relative value with the PVDF film value being 100%.

  In addition, 2 mg was taken out about one part resin composition film | membrane among the obtained said various resin composition films | membranes, and Tg (glass transition temperature) was measured by DSC (differential scanning calorimetry).

  The measurement results and the like are summarized in Tables 1 to 3.

  As is apparent from the results shown in Table 3, it can be seen that the piezoelectric properties and pyroelectric properties of the organic piezoelectric film formed from the resin composition of the present invention are superior to those of the comparative example.

Example 4
(Preparation and evaluation of ultrasonic probe)
<Production of piezoelectric material for transmission>
Component raw materials CaCO ₃ , La ₂ O ₃ , Bi ₂ O ₃ and TiO ₂ , and subcomponent raw materials MnO are prepared, and for the component raw materials, the final composition of the components is (Ca _0.97 La _0.03 ) Weighed to be Bi _4.01 Ti ₄ O ₁₅ . Next, pure water was added, mixed in a ball mill containing zirconia media in pure water for 8 hours, and sufficiently dried to obtain a mixed powder. The obtained mixed powder was temporarily molded and calcined in air at 800 ° C. for 2 hours to prepare a calcined product. Next, pure water was added to the obtained calcined material, finely pulverized in a ball mill containing zirconia media in pure water, and dried to prepare a piezoelectric ceramic raw material powder. In pulverization, the piezoelectric ceramic raw material powder having a particle diameter of 100 nm was obtained by changing the pulverization time and pulverization conditions. 6% by mass of pure water as a binder is added to each piezoelectric ceramic raw material powder having a different particle diameter, press-molded to form a plate-shaped temporary molded body having a thickness of 100 μm, and this plate-shaped temporary molded body is vacuum-packed and then 235 MPa. It shape | molded by the press with the pressure of. Next, the molded body was fired. The final sintered body had a thickness of 20 μm. The firing temperature was 1100 ° C. An electric field of 1.5 × Ec (MV / m) or more was applied for 1 minute to perform polarization treatment.

<Production of laminated resonator for reception>
A laminated vibrator was produced in which the organic piezoelectric film produced in Example 1 and a polyester film having a thickness of 50 μm were bonded together with an epoxy adhesive. Thereafter, polarization treatment was performed in the same manner as described above.

  Next, according to a conventional method, an ultrasonic probe was prototyped by laminating a laminated receiver for reception on the above-described piezoelectric material for transmission and installing a backing layer and an acoustic matching layer.

  As a comparative example, a probe similar to the above-described ultrasonic probe was manufactured using the comparative resin composition film-1 instead of the above-described laminated resonator for reception.

  Next, the above two types of ultrasonic probes were evaluated by measuring the reception sensitivity and the dielectric breakdown strength.

Incidentally, the reception sensitivity is originating the fundamental frequency _{f 1} of 5 MHz, to determine the received relative sensitivity of 20MHz as 15 MHz, 4 harmonics as received second harmonic wave _{f 2} as 10 MHz, 3 harmonic. For the relative sensitivity of reception, a sound intensity measurement system Model 805 (1 to 50 MHz) manufactured by Sonora Medical System, Inc. (2021 Miller Drive Longmont, Colorado (0501 USA)) was used.

  The dielectric breakdown strength was measured by multiplying the load power P by 5 times, testing for 10 hours, and then returning the load power to the reference to evaluate the relative reception sensitivity. The sensitivity was evaluated as good when the decrease in sensitivity was within 1% before the load test, more than 1% and less than 10%, and 10% or more as bad.

  In the above evaluation, the ultrasonic probe including the receiving piezoelectric (body) laminated vibrator according to the present invention has a relative receiving sensitivity of about 2.0 times that of the comparative example, and has a dielectric breakdown. It was confirmed that the strength was good. That is, it was confirmed that the ultrasonic wave receiving transducer of the present invention can be suitably used for a probe used in an ultrasonic medical image diagnostic apparatus as shown in FIG.

1 Receiving piezoelectric material (film)
2 Support 3 Piezoelectric material for transmission (film)
4 Backing layer 5 Electrode 6 Acoustic lens

Claims (7)

An organic piezoelectric material comprising a resin composition having a partial structure represented by the following general formula (UR1), wherein the resin composition has a glass transition temperature of 100 to 180 ° C. .

(In the formula, R ₁ and R ₂ each independently represent a hydrogen atom or a substituent, and n represents an integer of 1 to _3. R ₃ , R ₄ , R ₇ and R ₈ are each independently a hydrogen atom, alkyl. R ₅ and R ₆ each independently represents a hydrogen atom, an alkyl group or an aryl group, L ₁ represents an alkylene group or an arylene group, L ₂ represents a simple bond type, an alkyleneoxy group, an arylene X represents an oxygen atom, a sulfur atom or a nitrogen atom, the nitrogen atom may have a substituent, and Y represents an oxygen atom or a sulfur atom.) 2. The organic piezoelectric material according to claim 1, wherein an electromechanical coupling constant of the organic piezoelectric material is 0.20 or more. The organic piezoelectric material according to claim 1, wherein the organic piezoelectric material is subjected to a polarization treatment by an electric field or a combination of an electric field and a magnetic field. An ultrasonic transducer comprising the organic piezoelectric material according to claim 1 and an electrode. An ultrasonic probe comprising the ultrasonic transducer according to claim 4. The ultrasonic probe according to claim 5, wherein the ultrasonic transducer is a receiving ultrasonic transducer. An ultrasonic medical image diagnostic apparatus comprising the ultrasonic probe according to claim 5.

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