JP2018192588A - Surface modification method, ultrasonic transmission member and surface modification device - Google Patents

Abstract

To provide a surface modification method which dispenses with a step of spraying a peening material such as of a steel ball or jetting high-pressure water and is modifying the surface of a modification workpiece uniformly and high-densely with a simple means, and to provide an ultrasonic transmission member and a surface modification device excellent in operability and capable of modifying the surface of the modification workpiece at low cost.SOLUTION: There are provided: a surface modification method, where an ultrasonic transmission member is configured of a liquid crystal polymer, to form compression residual stress in the surface of a modification workpiece by giving ultrasonic waves to the surface of the modification workpiece, in a liquid, via an ultrasonic transmission member; an ultrasonic transmission member configured of liquid crystal polymer; and a surface modification device including the same.SELECTED DRAWING: None

Description

  The present invention relates to a method for modifying the surface of a material to be modified, and an ultrasonic transmission member and a surface modifying apparatus used in the method.

  Conventionally, shot peening in which a steel ball or a hard object is hit against the surface of a material to be reformed is known as a surface modification technique that forms a compressive residual stress on the surface of a material such as metal and relaxes the stress on the surface of the material. In this shot peening, a steel ball having a diameter of several millimeters is blown onto the surface of the material to be reformed by compressed air, and the surface of the material to be reformed is generated by an impact force generated when the steel ball collides with the surface of the material to be reformed. Compressive stress is formed on the surface. However, the method of hitting a steel ball or the like requires a peening material such as a steel ball and a step of blowing compressed air, and if the surface shape of the material to be reformed is complicated, the compression stress forming effect becomes non-uniform. At the same time, there has been a problem that steel balls or the like are retained in the recesses of the material to be reformed and recovery thereof becomes difficult.

  As a method that does not use peening materials such as steel balls, surface modification by water jet peening is performed in which high-pressure water is jetted from a nozzle in the water, and the underwater water jet with cavitation collides with the surface to be processed to improve the stress on the surface to be processed A quality method is also known (Patent Document 1). However, this method also requires a facility for injecting high-pressure water. When the surface to be processed has a complicated shape, cavitation occurs and the compressive stress formation effect is not uniform.

  As a method that does not require peening materials such as steel balls or special equipment, the object to be reformed is caused by the cavitation action that occurs when a vibrating body is placed on the surface of the material to be reformed with a liquid interposed and the vibrating body is vibrated at high frequency. A method for imparting a peening effect to a material has been proposed (Patent Document 2).

  In this method, cavitation bubbles are generated in the liquid, and compressive residual stress is formed on the surface of the material to be modified by peening using shock waves generated and collapsed. There is an effect that a process such as spraying of a peening material, compressed air, and injection of high-pressure water becomes unnecessary.

  High-frequency vibration is performed by applying an ultrasonic band, that is, an ultrasonic wave. However, formation of compressive residual stress due to generation of cavitation bubbles requires a long time and it is difficult to perform uniform surface modification. In particular, in the case where the surface shape of the material to be modified is complicated or in the case of the material to be modified having a small size, the tendency is remarkable, and further improvement has been demanded.

Japanese Patent No. 3373738 JP 2003-220523 A

  The object of the present invention is to eliminate the need for steps such as peening materials such as steel balls, spraying of compressed air, and high pressure water injection, and compressive residual stress uniformly and densely on the surface of the material to be reformed by simple means. It is an object of the present invention to provide a surface modification method capable of forming a surface.

  Another object of the present invention is to provide an ultrasonic transmission member and a surface modification device that are excellent in operability and can form a compressive residual stress uniformly and densely on the surface of a material to be modified at low cost. It is in.

  As a result of intensive studies on a method for forming a compressive residual stress by applying ultrasonic waves and modifying the surface of a material to be modified, the present inventors have conducted ultrasonic transmission composed of a liquid crystal polymer in a liquid. It has been found that the surface modification effect of the material to be modified is significantly improved by applying ultrasonic waves through the member, and the present invention has been completed.

  That is, the present invention provides a surface modification method in which ultrasonic waves are applied to a surface of a material to be modified via an ultrasonic transmission member in a liquid to form a compressive residual stress on the surface of the material to be modified.

  The present invention is also an ultrasonic transmission member that modifies the surface by transmitting ultrasonic waves to the surface of the material to be modified and forming a compressive residual stress on the surface of the material to be modified, and is composed of a liquid crystal polymer. An ultrasonic transmission member is provided.

  The present invention also includes an ultrasonic wave generation means having an ultrasonic wave transmission member for transmitting ultrasonic waves generated from an ultrasonic vibrator to the surface of the material to be modified, and a container for containing the material to be modified in a liquid. A surface modification device in which an ultrasonic transmission member is made of a liquid crystal polymer is provided.

  The surface modification method and the surface modification apparatus of the present invention use an ultrasonic transmission member composed of a liquid crystal polymer to form a compressive residual stress on the surface of the material to be reformed with high density and uniformity. The surface of the modifying material can be efficiently modified. In particular, even when the surface shape of the material to be reformed is complicated or even a material to be reformed having a small size can be efficiently modified.

It is a schematic sectional drawing explaining the 1st embodiment of the surface modification apparatus of this invention. It is a schematic sectional drawing explaining the 2nd embodiment of the surface modification apparatus of this invention. It is a schematic sectional drawing explaining the 3rd embodiment of the surface modification apparatus of this invention. It is a schematic sectional drawing explaining the 4th embodiment of the surface modification apparatus of this invention.

  In the surface modification method of the present invention, ultrasonic waves are applied to the surface of the material to be modified immersed in a liquid via an ultrasonic transmission member made of a liquid crystal polymer.

  By passing through an ultrasonic transmission member composed of a liquid crystal polymer, the ultrasonic waves become unsteady and uniform sound pressure, resulting in high density and uniform cavitation bubbles in the liquid, thus forming compressive residual stress. It is estimated that the surface modification effect is improved.

  Although the example of the surface modification apparatus used for the surface modification method of this invention is given to the following, it does not intend that the structure of a surface modification apparatus is limited to these.

  A first embodiment of the surface modification apparatus of the present invention is shown in FIG. The surface modifying apparatus 1 includes an ultrasonic wave generating unit 2 disposed at a position facing the surface to be treated 41 of the material 4 to be modified.

  The ultrasonic generator 2 includes an ultrasonic transducer 21, an ultrasonic transmission member 22, and a cavitation generator 23, and generates ultrasonic waves by a current supplied from the ultrasonic power supply device 3 through the electric wire 31. Yes.

  As the ultrasonic transducer 21, for example, a material using a giant magnetostrictive material or a piezoelectric ceramic material is preferably used.

  The ultrasonic transmission member 22 is a member that is made of a liquid crystal polymer and transmits ultrasonic waves generated by the ultrasonic transducer 21. The ultrasonic transmission member 22 is joined to the ultrasonic transducer 21 by fixing means such as adhesion or screwing. The shape and dimensions of the ultrasonic transmission member can be appropriately set according to the material to be modified and the ultrasonic vibrator. The thickness of the ultrasonic transmission member may be, for example, 0.1 to 20 mm.

  The cavitation generating unit 23 is made of metal, ceramic, or a resin material containing a liquid crystal polymer. The cavitation generating unit 23 has a cavitation generating surface 24 and is joined to the ultrasonic transmission member 22 by fixing means such as adhesion or screwing. When the cavitation generating unit 23 is made of a liquid crystal polymer, the cavitation generating unit 23 may be integrally formed with the ultrasonic transmission member 22.

  The shape of the cavitation generating part 23 is not particularly limited, but for example, it can be a flat plate or the like, and from the viewpoint of generating more complex ultrasonic waves, an uneven surface such as a lattice-like groove or rib It may have a structure or a mesh shape. When the ultrasonic wave generating means 2 is movable with respect to the material 4 to be modified, it may be horn-shaped or bar-shaped.

  The ultrasonic wave generated by the ultrasonic transducer 21 is transmitted to the cavitation generating unit 23 via the ultrasonic transmission member 22 joined to the ultrasonic transducer 21, and the gap 10 between the cavitation generating surface 24 and the surface to be processed 41. Cavitation bubbles 9 are generated in the liquid 8 present in

  The gap 10 which is the shortest distance between the cavitation generating surface 24 and the surface to be processed 41 is preferably 100 μm to 10 mm, more preferably 500 μm to 5 mm from the viewpoint of obtaining a sufficient surface modification effect.

  The ultrasonic wave generation means 2 is disposed close to the lower portion of the material to be modified 4 by the support means 5 so that the cavitation generation surface 24 faces the processing surface 41.

  The support unit 5 supports the ultrasonic wave generation unit 2 by bonding one side to the ultrasonic wave generation unit 2 and bonding the other side to, for example, the inner wall of the container 6.

  The support unit 5 may be configured to apply ultrasonic waves to the material to be modified 4 while moving the ultrasonic wave generation unit 2.

  The container 6 holds the liquid 8 so that at least the cavitation generating surface 24 and the surface to be processed 41 are immersed. The container 6 only needs to be able to fill the gap 10 with the liquid 8, and may be, for example, a tank shape.

  As the liquid 8 filling the space between the cavitation generating surface 24 and the surface 41 to be processed, water, an aqueous solution, oil, an organic solvent, or the like can be used.

  The to-be-reformed material 4 is supported by the to-be-modified material support means 7 at a position where the surface to be treated 41 faces the cavitation generating surface 24.

  Although it does not specifically limit as a material of the to-be-reformed material 4 which concerns on this invention, For example, a metal, ceramics, resin, etc. are mentioned. Of these, metals are preferred. Examples of the metal include iron, carbon steel, stainless steel, aluminum alloy, and magnesium alloy.

  The frequency of the ultrasonic wave according to the present invention may be in any region from a low frequency to a high frequency, but is preferably 20 kHz to 5 MHz, more preferably 30 kHz to 4 MHz from the viewpoint that surface modification is more effective. 50 kHz to 3 MHz is more preferable.

  The frequency of the ultrasonic wave in the ultrasonic power supply device 3 is, for example, 1 to 10 seconds as a period from the point of increasing the unsteadiness and uniformity of the ultrasonic wave and further improving the homogenization effect of the surface modification. It may be changed continuously or intermittently between 1 MHz and 5 MHz.

  A second embodiment of the surface modification apparatus of the present invention is shown in FIG.

  In the second embodiment, the ultrasonic wave generating means 2 is placed on the upper part of the material to be reformed 4 arranged at the bottom of the container 6 so that the cavitation generating surface 24 faces the surface to be processed 41 by the supporting means 5. Closely arranged.

  In the second embodiment, since the material to be reformed is disposed at the bottom of the container 6, the material support means need not be provided.

  A third embodiment of the surface modification apparatus of the present invention is shown in FIG.

  In the third embodiment, the container 6 is made of a liquid crystal polymer, and the cavitation generator 23 is provided at a portion facing the material to be reformed 4.

  The ultrasonic transducer 21 is joined to the outside of the container 6, but may be joined to the inside of the container 6 as long as cavitation generation is not hindered.

  In the third embodiment, since at least a part of the container 6 is made of a liquid crystal polymer, the part made of the liquid crystal polymer serves as an ultrasonic transmission member, and the part made of the liquid crystal polymer of the container 6 The surface of the cavitation generating unit 23 and / or the inner wall surface of the container 6 that is in contact with each other serves as the cavitation generating surface 24. In the third embodiment, the supporting means for supporting the ultrasonic wave generating means is not necessary. Also in the third embodiment, when the cavitation generator 23 is made of a liquid crystal polymer, it may be integrally formed with a portion of the container 6 made of the liquid crystal polymer.

  The material to be reformed 4 is disposed close to the bottom of the container 6 so that the surface 41 to be treated faces the inner wall surface of the container 6.

  A fourth embodiment of the surface modification apparatus of the present invention is shown in FIG.

  In the fourth embodiment, the ultrasonic transducer 21 and the ultrasonic transmission member 22 are indirectly connected.

  That is, the ultrasonic wave generated by the ultrasonic vibrator 21 is transmitted to the cavitation generating unit 24 via the container 6 and the ultrasonic transmission member 22 to generate cavitation bubbles between the cavitation generating surface and the surface to be modified. .

  The ultrasonic transducer 21 is preferably joined to the outside of the container 6, but may be joined to the inside.

  In the fourth embodiment, since the ultrasonic transmission member 22 is configured to be mounted on or bonded to the container 6, a support unit for supporting the ultrasonic wave generation unit is not necessary.

  In the first to fourth embodiments, the case where cavitation is generated above or below the material to be reformed 4 has been described, but in any mode, in addition to or in place of the above, the material to be reformed Cavitation bubbles may be generated on the side of the material 4. Further, it may be a mode in which the first to fourth embodiments are combined, that is, a mode in which cavitation is generated above and below the material to be reformed. Bubbles may be generated.

  The liquid crystal polymer used in the present invention is a liquid crystal polyester resin or liquid crystal polyester amide resin that forms an anisotropic molten phase, which is called a thermotropic liquid crystal polymer by those skilled in the art.

  The property of the anisotropic molten phase of the liquid crystal polymer can be confirmed by a normal deflection inspection method using an orthogonal deflector, that is, by observing a sample placed on a hot stage in a nitrogen atmosphere.

  The liquid crystal polymer used in the present invention may be either a semi-aromatic liquid crystal polymer having an aliphatic group in the molecular chain, or a wholly aromatic liquid crystal polymer in which the molecular chain is entirely composed of aromatic groups.

  As the repeating unit constituting the liquid crystal polymer used in the present invention, aromatic oxycarbonyl repeating unit, aromatic dicarbonyl repeating unit, aromatic dioxy repeating unit, aromatic aminooxy repeating unit, aromatic diamino repeating unit, aromatic Examples thereof include aminocarbonyl repeating units, aromatic oxydicarbonyl repeating units, aliphatic dioxy repeating units, and aliphatic dicarbonyl repeating units.

  Specific examples of the monomer that gives an aromatic oxycarbonyl repeating unit include, for example, 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy- Aromatics such as 2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4′-hydroxyphenyl-4-benzoic acid, 3′-hydroxyphenyl-4-benzoic acid, 4′-hydroxyphenyl-3-benzoic acid Examples thereof include hydroxycarboxylic acids and alkyl, alkoxy or halogen substituted products thereof, and ester-forming derivatives thereof such as acylated products, ester derivatives and acid halides thereof. Among these, 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferable from the viewpoint of easy adjustment of the characteristics and crystal melting temperature of the liquid crystal polymer obtained.

  Specific examples of the monomer that gives an aromatic dicarbonyl repeating unit include, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1 Aromatic dicarboxylic acids such as 1,4-naphthalenedicarboxylic acid and 4,4′-dicarboxybiphenyl and their alkyl, alkoxy or halogen substituents, and ester-forming derivatives such as ester derivatives and acid halides thereof. . Among these, terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferable because the mechanical properties, heat resistance, crystal melting temperature, and molding processability of the liquid crystal polymer from which terephthalic acid, 2,6-naphthalenedicarboxylic acid are obtained can be easily adjusted to appropriate levels.

  Specific examples of the monomer that provides an aromatic dioxy repeating unit include, for example, hydroquinone, resorcin, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, Aromatic diols such as 4,4′-dihydroxybiphenyl, 3,3′-dihydroxybiphenyl, 3,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl ether and their alkyl, alkoxy or halogen substituents, and these And ester-forming derivatives such as acylated products. Among these, hydroquinone and 4,4′-dihydroxybiphenyl are preferable because they are easy to adjust the reactivity during polymerization and the mechanical properties, heat resistance, crystal melting temperature, and moldability of the obtained liquid crystal polymer to appropriate levels. .

  Specific examples of the monomer that gives an aromatic aminooxy repeating unit include, for example, 4-aminophenol, 3-aminophenol, 4-amino-1-naphthol, 5-amino-1-naphthol, and 8-amino-2. -Aromatic hydroxyamines such as naphthol, 4-amino-4'-hydroxybiphenyl and their alkyl, alkoxy or halogen substitutions, and ester-forming derivatives such as their acylates.

  Specific examples of the monomer that gives an aromatic diamino repeating unit include aromatic diamines such as 1,4-diaminobenzene, 1,3-diaminobenzene, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, and the like. And alkyl, alkoxy or halogen substitution products thereof, and amide-forming derivatives thereof such as acylated products thereof.

  Specific examples of the monomer that gives an aromatic aminocarbonyl repeating unit include aromatic aminocarboxylic acids such as 4-aminobenzoic acid, 3-aminobenzoic acid, and 6-amino-2-naphthoic acid, and alkyls thereof. , Alkoxy- or halogen-substituted products, and ester-forming derivatives thereof such as acylated products, ester derivatives, and acid halides.

  Specific examples of monomers that give aromatic oxydicarbonyl repeat units include hydroxy aromatic dicarboxylic acids such as 3-hydroxy-2,7-naphthalenedicarboxylic acid, 4-hydroxyisophthalic acid, and 5-hydroxyisophthalic acid. Examples include acids and their alkyl, alkoxy or halogen-substituted products, and ester-forming derivatives thereof such as acylated products, ester derivatives and acid halides thereof.

  Specific examples of the monomer that gives an aliphatic dihydroxy repeating unit include aliphatic diols such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and acylated products thereof. In addition, polymers containing aliphatic dioxy repeating units such as polyethylene terephthalate and polybutylene terephthalate are converted into the above-mentioned aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols and their acylated products, ester derivatives, acid halides. A liquid crystal polymer containing an aliphatic dioxy repeating unit can also be obtained by reacting with the above.

  Specific examples of the monomer that gives the aliphatic dicarbonyl repeating unit include, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, and tetradecane. Examples thereof include aliphatic dicarboxylic acids such as diacid, fumaric acid, maleic acid and hexahydroterephthalic acid, and ester-forming derivatives thereof such as ester derivatives and acid halides thereof.

  The liquid crystal polymer used in the present invention may contain a thioester bond as long as the object of the present invention is not impaired. Examples of the monomer that gives such a bond include mercapto aromatic carboxylic acid, aromatic dithiol, and hydroxy aromatic thiol. The amount of these monomers used is aromatic oxycarbonyl repeating unit, aromatic dicarbonyl repeating unit, aromatic dioxy repeating unit, aromatic aminooxy repeating unit, aromatic diamino repeating unit, aromatic aminocarbonyl repeating unit, It is preferably 10 mol% or less based on the total amount including the total amount of monomers that give the aromatic oxydicarbonyl repeating unit, aliphatic dioxy repeating unit, and aliphatic dicarbonyl repeating unit.

  Depending on the composition and composition ratio of the monomers and the sequence distribution of each repeating unit in the polymer, polymers that combine these repeating units may or may not form an anisotropic molten phase. The liquid crystal polymer used is limited to those forming an anisotropic melt phase.

Specific examples of the liquid crystal polymer used in the present invention include a copolymer composed of repeating units given by the following combination of monomers.
1) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid copolymer 2) 4-hydroxybenzoic acid / terephthalic acid / 4,4′-dihydroxybiphenyl copolymer 3) 4-hydroxybenzoic acid / terephthalic acid / Isophthalic acid / 4,4′-dihydroxybiphenyl copolymer 4) 4-hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4′-dihydroxybiphenyl / hydroquinone copolymer 5) 4-hydroxybenzoic acid / terephthalic acid / Hydroquinone copolymer 6) 6-hydroxy-2-naphthoic acid / terephthalic acid / hydroquinone copolymer 7) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / 4,4′-dihydroxybiphenyl Copolymer 8) 6-Hydroxy-2-naphthoic acid / terephthalic acid / 4,4'-dihydride Xibiphenyl copolymer 9) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / hydroquinone copolymer 10) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / hydroquinone / 4,4'-dihydroxybiphenyl copolymer 11) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / 4,4'-dihydroxybiphenyl copolymer 12) 4-hydroxybenzoic acid / terephthalic acid / 2 6-Naphthalenedicarboxylic acid / hydroquinone copolymer 13) 4-hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 14) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / 2,6 -Naphthalenedicarboxylic acid / hydroquinone copolymer 15) 4-hydroxy Benzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone / 4,4′-dihydroxybiphenyl copolymer 16) 4-hydroxybenzoic acid / terephthalic acid / 4-aminophenol copolymer 17) 6-hydroxy- 2-naphthoic acid / terephthalic acid / 4-aminophenol copolymer 18) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / 4-aminophenol copolymer 19) 4-hydroxybenzoic acid / Terephthalic acid / 4,4′-dihydroxybiphenyl / 4-aminophenol copolymer 20) 4-hydroxybenzoic acid / terephthalic acid / ethylene glycol copolymer 21) 4-hydroxybenzoic acid / terephthalic acid / 4,4′- Dihydroxybiphenyl / ethylene glycol copolymer 22) 4-hydroxy Benzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / ethylene glycol copolymer 23) 4-hydroxybenzoic acid / 6-hydroxy-2-naphthoic acid / terephthalic acid / 4,4′-dihydroxybiphenyl / ethylene Glycol copolymer 24) 4-hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / 4,4′-dihydroxybiphenyl copolymer.

  Among these, liquid crystal polymers composed of the monomer structural units of 1), 9), 10) and 14) are preferable.

  The liquid crystal polymer used in the present invention may be a blend of two or more liquid crystal polymers.

  The melt viscosity of the liquid crystal polymer used in the present invention (measured with a capillary rheometer, the measurement temperature is crystal melting temperature + 10 ° C. to crystal melting temperature + 40 ° C., 1000 s-1) is the mechanical strength of the ultrasonic transmission member according to the present invention. From the point to ensure, 5-1000 Pa.s is preferable, 10-300 Pa.s is more preferable, 15-200 Pa.s is further more preferable.

  In the present specification and claims, “crystal melting temperature” refers to crystal melting measured by a differential scanning calorimeter (hereinafter abbreviated as DSC) at a heating rate of 20 ° C./min. It is obtained from the peak temperature. More specifically, after observing an endothermic peak temperature (Tm1) observed when a liquid crystal polymer sample is measured from room temperature under a temperature rising condition of 20 ° C./min, the temperature is 10 to 50 ° C. higher than Tm1. Hold for a minute, then cool the sample to room temperature under a temperature drop condition of 20 ° C./min, then observe the endothermic peak when measured again under a temperature rise condition of 20 ° C./min, and the temperature showing the peak top is the liquid crystal The crystal melting temperature of the polymer. As the measuring device, for example, Exstar 6000 manufactured by Seiko Instruments Inc. can be used.

  The liquid crystal polymer used in the present invention can measure logarithmic viscosity in pentafluorophenol. The liquid crystal polymer used in the present invention preferably has a logarithmic viscosity of 0.3 dl / g or more when measured at a temperature of 60 ° C. in pentafluorophenol (concentration: 0.1 g / dl). / G is more preferable, and 1 to 8 dl / g is more preferable.

  The production method of the liquid crystal polymer used in the present invention is not particularly limited, and a known polycondensation method for forming an ester bond or an amide bond with the above monomer components, for example, a melt acidosis method, a slurry polymerization method, or the like is used. Can do.

  The melt acidolysis method is a method suitable for producing the liquid crystal polymer used in the present invention, and this method is a method in which a monomer is first heated to form a melt of a reactant and the reaction is continued. Thus, a molten polymer is obtained. A vacuum may be applied to facilitate removal of volatiles (for example, acetic acid, water, etc.) by-produced in the final stage of the condensation.

  The slurry polymerization method is a method of reacting in the presence of a heat exchange fluid, and the solid product is obtained in a state suspended in a heat exchange medium.

  In both the melt acidification method and the slurry polymerization method, the polymerizable monomer component used for producing the liquid crystal polymer is reacted at room temperature as a modified form in which the hydroxyl group is acylated, that is, a lower acylated product. Can also be provided. The lower acyl group preferably has 2 to 5 carbon atoms, more preferably 2 or 3 carbon atoms. Particularly preferred is a method using an acetylated product of the monomer component in the reaction.

  The lower acylated product of the monomer may be separately acylated and synthesized in advance, or may be produced in the reaction system by adding an acylating agent such as acetic anhydride to the monomer during the production of the liquid crystal polymer. .

  In either case of the melt acidolysis method or the slurry polymerization method, a catalyst may be used as needed during the reaction.

Specific examples of the catalyst include, for example, organic tin compounds (dialkyltin oxide such as dibutyltin oxide, diaryltin oxide), organic titanium compounds (titanium dioxide, antimony trioxide, alkoxy titanium silicate, titanium alkoxide, etc.), carboxylic acid Examples thereof include gaseous acid catalysts such as alkali and alkaline earth metal salts (such as potassium acetate and sodium acetate), Lewis acids (such as BF ₃ ), and hydrogen halides (such as HCl).

  10-1000 ppm is preferable with respect to a monomer weight, and, as for the usage-amount of a catalyst, 20-200 ppm is more preferable.

  The liquid crystal polymer obtained by such a polycondensation reaction is extracted from the polymerization reaction tank in a molten state, and then processed into pellets, flakes, or powders for use in molding.

  The liquid crystal polymer used in the present invention may further contain an inorganic and / or organic filler as an optional component from the viewpoint of further improving the mechanical strength of the ultrasonic transmission member.

  Specific examples of the inorganic and / or organic filler that may be contained in the liquid crystal polymer used in the present invention include, for example, glass fiber, silica alumina fiber, alumina fiber, carbon fiber, potassium titanate fiber, and aluminum borate fiber. , Aramid fibers, polyarylate fibers, talc, mica, graphite, wollastonite, dolomite, clay, glass flakes, glass beads, glass balloons, calcium carbonate, barium sulfate, titanium oxide, etc. Or two or more of them may be used in combination.

  In these, a talc and glass fiber are preferable at the point with the outstanding balance of a physical property and cost.

  Further, the inorganic and / or organic filler may be subjected to a surface treatment. Examples of the surface treatment method include a method of adsorbing a surface treatment agent on the surface of the filler, a method of adding a surface treatment agent when kneading the liquid crystal polymer and the filler, and the like.

  Surface treatment agents include reactive coupling agents (silane coupling agents, titanate coupling agents, borane coupling agents, etc.), lubricants (higher fatty acids, higher fatty acid esters, higher fatty acid metal salts, fluorocarbon surface activity) Agent).

  The content of the inorganic and / or organic filler is preferably 1 to 150 parts by weight and more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the liquid crystal polymer.

  If the content of the inorganic and / or organic filler is less than 1 part by weight, the strength of the ultrasonic transmission member tends to be difficult to improve, and if it exceeds 150 parts by weight, the strength of the ultrasonic transmission member Tends to decrease.

  Other additives may be further added to the liquid crystal polymer used in the present invention as long as the object of the present invention is not impaired.

  Specific examples of other additives include, for example, lubricants (higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid metal salts (herein higher fatty acids are those having 10 to 25 carbon atoms), etc.) , Mold release improver (polysiloxane, fluorine resin, etc.), colorant (dye, pigment, carbon black, etc.), flame retardant, antistatic agent, surfactant, nucleating agent (talc, organophosphate, sorbitols) Etc.), anti-blocking agents, antioxidants (phosphorus-based antioxidants, phenol-based antioxidants, sulfur-based antioxidants, etc.), weathering agents, heat stabilizers, neutralizing agents and the like. These additives may be used alone or in combination of two or more.

  0.01-5 weight part is preferable with respect to 100 weight part of liquid crystal polymers, and, as for the total amount of the other additive which may be added, 0.1-3 weight part is more preferable.

  When the total amount of the other additives is less than 0.01 parts by weight, the function of the additive tends to be difficult to be realized. When the total amount exceeds 5 parts by weight, the liquid crystal polymer or the liquid crystal polymer composition is molded. Thermal stability tends to be poor.

  Other resin components may be further added to the liquid crystal polymer used in the present invention as long as the object of the present invention is not impaired.

  Specific examples of other resin components include, for example, polyamide, polyester, polyacetal, polyphenylene ether, and modified products thereof, and thermoplastic resins such as polysulfone, polyethersulfone, polyetherimide, and polyamideimide, phenol resin, and epoxy. Examples thereof include thermosetting resins such as resins and polyimide resins. These resin components may be used alone or in combination of two or more.

  When the other resin component is contained, the content of the resin component is preferably 0.1 to 100 parts by weight, more preferably 0.1 to 80 parts by weight with respect to 100 parts by weight of the liquid crystal polymer.

  The liquid crystal polymer used in the present invention is a mixture of a liquid crystal polymer and a compatibilizer, inorganic and / or organic filler, other additives or other resin components, and a Banbury mixer, kneader, single-screw or twin-screw extruder. Can be obtained by melt-kneading from the vicinity of the crystal melting temperature of the liquid crystal polymer under a temperature condition of crystal melting temperature + 50 ° C., and can be formed into an ultrasonic transmission member by a conventional method such as injection molding or extrusion molding.

  The modification method using the ultrasonic transmission member composed of the liquid crystal polymer of the present invention can be applied to, for example, surface modification of parts related to automobile members, building members, precision machines, industrial machines, and the like. .

  Hereinafter, although an example explains the present invention in detail, the present invention is not limited to this.

<Synthesis Example 1> (Synthesis of Liquid Crystal Polymer 1)
A reaction vessel equipped with a stirrer with a torque meter and a distillation tube was charged with 655.3 g (73 mol%) of 4-hydroxybenzoic acid and 330.3 g (27 mol%) of 6-hydroxy-2-naphthoic acid, and 1.02 moles of acetic anhydride was charged with respect to the amount (moles) of hydroxyl groups of all monomers, and deacetic acid polymerization was performed under the following conditions.

  The temperature was raised from room temperature to 170 ° C. over 1 hour under a nitrogen gas atmosphere, and the same temperature was maintained for 30 minutes. Next, the temperature was raised to 330 ° C. over 3 hours and further reacted at 330 ° C. for 10 minutes, and then the pressure was reduced to 10 mmHg over 1.5 hours. When the predetermined torque was exhibited, the polymerization reaction was terminated, the contents were taken out from the reaction vessel, and liquid crystal polymer pellets were obtained with a pulverizer.

<Synthesis Example 2> (Synthesis of Liquid Crystal Polymer 2)
In a reaction vessel equipped with a stirrer with a torque meter and a distillation tube, 628.4 g (70 mol%) of 4-hydroxybenzoic acid, 24.5 g (2 mol%) of 6-hydroxy-2-naphthoic acid, 2,6 -196.7 g (14 mol%) of naphthalenedicarboxylic acid and 100.2 g (14 mol%) of hydroquinone were charged, and 1.05 times mol of acetic anhydride was added to the amount of hydroxyl groups (mol) of all monomers, Deacetic acid polymerization was performed under the following conditions.

  The temperature was raised from room temperature to 170 ° C. over 1 hour in a nitrogen gas atmosphere, and maintained at 170 ° C. for 30 minutes. Next, the temperature was raised to 350 ° C. over 7 hours while distilling off the acetic acid produced as a by-product, and then the pressure was reduced to 5 mmHg over 1.5 hours. When the predetermined torque was exhibited, the polymerization reaction was terminated, the contents were taken out from the reaction vessel, and a wholly aromatic liquid crystal polymer pellet was obtained by a pulverizer.

<Production of ultrasonic transmission member>
With respect to the liquid crystal polymer pellets obtained in Synthesis Examples 1 and 2, flat plate samples (80 mm × 80 mm × 1 mmt) were prepared using an injection molding machine.

  Moreover, the flat plate sample was similarly produced about polyethylene resin (2100J by Prime Polymer Co., Ltd.).

  As the metallic ultrasonic transmission member, a steel plate (SPCC equivalent, 50 mm × 50 mm × 1 mmt) was used.

Example 1
An ultrasonic power supply device by adhering an ultrasonic transducer (ceramic oscillator, 2 mmφ × 1 mmt) to the lower surface of a flat plate made from the liquid crystal polymer pellet obtained in Synthesis Example 1 which is a sample of an ultrasonic transmission member, with a silicone-based adhesive (DAGATRONIC CORPORATION, DAGATRON 8202) was connected, and the frequency was adjusted using an oscilloscope (Pico Technology Limited).

  In the water tank, a steel plate (SPCC equivalent, 50 mm x 50 mm x 1 mmt) is placed as a material to be reformed at an interval of 1 mm on the top surface of the ultrasonic transmission member, and all of the material to be reformed including the surface to be treated is at room temperature. Then, ultrasonic waves were applied for 15 minutes at 100 kHz.

  The surface to be treated of the material to be modified is measured at 8 locations using a residual stress measuring device μ-x360n (manufactured by Pulstec Industrial Co., Ltd.) according to X-ray stress measurement (Japan Society of Materials Science, Steel). The average stress value and standard deviation were calculated.

  Compared to the value of the untreated material to be reformed, the smaller the stress value, the more effectively it was modified, and the smaller the standard deviation, the more uniformly reformed.

Example 2 and Comparative Examples 1-2
An ultrasonic wave was applied in the same manner as in Example 1 except that the ultrasonic transmission member was changed as shown in Table 1, and a residual stress value (average value) and a standard deviation were calculated. The results are shown in Table 1.

  As a reference example, Table 1 shows the residual stress values (average values) and standard deviations measured and calculated in the same manner as in Example 1 for the surface of the material to be modified before applying ultrasonic waves.

  When the liquid crystal polymer is used as an ultrasonic transmission member (Examples 1 and 2), the residual stress values are −25 MPa and −22 MPa, which are smaller than the untreated steel plate (reference example), and the standard deviation is small. 38 MPa and 42 MPa, indicating that a uniform and effective reforming effect was obtained.

  In contrast, stainless steel (SUS304) and polyethylene resin (Comparative Examples 1 and 2) had a larger standard deviation than the untreated steel sheet (Reference Example), and were inferior in the reforming effect.

DESCRIPTION OF SYMBOLS 1 Surface modification apparatus 2 Ultrasonic generation means 21 Ultrasonic vibrator 22 Ultrasonic transmission member 23 Cavitation generation part 24 Cavitation generation surface 3 Ultrasonic power supply device 31 Electric wire 4 To-be-modified material 41 To-be-processed surface 5 Support means 6 Container 7 Reformable material support means 8 Liquid 9 Cavitation bubble 10 Gap

Claims (3)

In a liquid, a surface modification method that applies ultrasonic waves to the surface of a material to be modified through an ultrasonic transmission member to form a compressive residual stress on the surface of the material to be modified,
A surface modification method in which an ultrasonic transmission member is composed of a liquid crystal polymer.   An ultrasonic transmission member that modifies the surface of a material to be modified by transmitting ultrasonic waves to the surface of the material to be modified and forming a compressive residual stress on the surface of the material to be modified. Ultrasonic transmission member.   A surface modification apparatus comprising an ultrasonic wave generation means having an ultrasonic wave transmission member for transmitting ultrasonic waves generated from an ultrasonic vibrator to the surface of a material to be modified, and a container for containing the material to be modified in a liquid. A surface modification device in which the ultrasonic transmission member is made of a liquid crystal polymer.

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