JP6396237B2 - Method for manufacturing film for speaker diaphragm - Google Patents

Description

  The present invention relates to a method for producing a lightweight speaker diaphragm film having excellent sound quality characteristics and heat resistance.

  Various electronic devices including a mobile phone, a smartphone, a portable music device, a portable game machine, a tablet personal computer, and the like incorporate a small speaker that reproduces sound. The diaphragm that generates sound waves by vibrating the speaker is (1) metal foil, (2) natural resin paper, woven fabric, or non-woven fabric, and (3) synthetic resin film, woven fabric, or non-woven fabric. Is formed.

  When the diaphragm is a film made of (3) synthetic resin, polyolefin resin such as polyethylene (PE) resin and polypropylene (PP) resin, polyethylene terephthalate (PET) resin, polyethylene terephthalate (PEN) resin (Patent Literature) 1) and the like, and synthetic resin films made of polyphenylene sulfide (PPS) resin or the like have been proposed and used.

  By the way, in recent years, more and more functions and performance are being improved in speakers. Therefore, the required characteristics for the diaphragm of the speaker are becoming increasingly severe. The required properties required for this diaphragm are light weight (low density or low specific gravity), moderate rigidity (Young's modulus, elastic modulus), excellent thickness accuracy, high strength, and durability. And the like. In addition to these characteristics, heat resistance, moisture resistance or water resistance, and moldability (press molding, vacuum forming, pressure forming, etc.) are also included.

Japanese Patent Application Laid-Open No. Sho 62-26397 JP-A-60-139098 JP 58-222699 A JP 2007-43597 A

However, when the diaphragm is made of (1) metal foil, it is excellent in moisture resistance, water resistance, and heat resistance, but has a high density and rigidity, so that the minimum resonance frequency (f ₀ ) is high, and the reproduction characteristic of bass is insufficient It becomes. When the diaphragm is (2) natural resin paper, woven fabric, or non-woven fabric, the density is low and the weight is low, but there are problems in moisture resistance, water resistance, and heat resistance. In addition, the manufacturing process of the speaker is complicated and problematic.

  When the diaphragm is a film made of (3) synthetic resin, specifically a film made of polyolefin resin, it is lightweight and has a large loss tangent and is excellent in moisture resistance, water resistance, or moldability, but has low rigidity. Problems arise in heat resistance.

Further, in the case of a film made of polyethylene terephthalate resin, it is excellent in rigidity and heat resistance as compared with a polyolefin resin film, but the loss tangent is small and the sound quality is insufficient. Further, since the density is as large as 1.4 g / cm ³ , it is not possible to reduce the weight. Moreover, since the diaphragm which consists of a film made from a polyethylene terephthalate resin will deform | transform at the temperature of about 70 degreeC, heat resistance is inadequate.

In addition, in the case of a film made of polyethylene naphthalate resin, it has high strength, excellent durability, very large loss tangent, and excellent sound quality characteristics. It is necessary to perform orientation. However, when the film is highly oriented, the rigidity (elastic modulus) of the film is increased, so that the lowest resonance frequency (f ₀ ) is increased and the bass reproduction characteristic is insufficient. Moreover, when it is highly oriented, the formability of the film, such as press molding, vacuum forming, or pressure forming, is lowered. In addition, the density is as large as 1.36 g / cm ^3, and weight reduction cannot be achieved.

In the case of a film made of polyphenyl sulfide resin, it has high strength, excellent durability, and excellent heat resistance. However, in order to bring out these properties, it needs to be oriented by advanced biaxial stretching. However, when the orientation is high, the lowest resonance frequency (f ₀ ) is increased as described above, so that the low-frequency sound reproduction characteristics are insufficient, and the moldability such as press molding, vacuum molding, or pressure molding of the film is also achieved. descend. In the case of a film made of polyphenylene sulfide resin, the loss tangent is small, causing a problem in sound quality. In addition, since the density is as large as 1.37 g / cm ³ , the weight reduction is hindered.

  In view of the above, a film made of polyetherimide (PEI) resin or a film made of polyetheretherketone (PEEK) resin has been proposed and used as a film for a diaphragm (Patent Documents 2, 3, and 4). reference).

  Polyetherimide resin is lighter in density and lighter than polyethylene terephthalate resin, polyethylene naphthalate resin, and polyphenylene sulfide resin. In addition, since the polyetherimide resin is an amorphous resin, when forming a film, compared to a film made of a crystalline resin such as polyethylene terephthalate resin, polyethylene naphthalate resin, or polyphenylene sulfide resin, the diaphragm is molded. It has excellent properties (diaphragm molding: press molding, pressure molding, vacuum molding, etc.). Furthermore, the polyetherimide resin film has a high loss tangent, so it has excellent sound quality characteristics. Speakers for various small electronic devices such as mobile phones, smartphones, portable music devices, portable game machines, and tablet personal computers have been used. Or, it is used for a diaphragm of a vehicle-mounted speaker.

  However, it has been reported that the heat resistant temperature of a diaphragm made of a film made of polyetherimide resin is 150 ° C. or less (Patent Document 3). Therefore, sufficient heat resistance cannot be obtained with a film made of polyetherimide resin. In addition, since the strength is small, there is a problem that if the external output is increased, the film is torn.

On the other hand, it has been reported that the heat resistant temperature of a diaphragm obtained from a film made of polyetheretherketone (PEEK) resin is about 200 to about 300 ° C., which is more heat resistant than polyetherimide resin. Is excellent. However, the elastic modulus (tensile elastic modulus) of the polyetheretherketone resin film is very large and exceeds 2800 N / mm ² . Therefore, the diaphragm obtained from this film has a high minimum resonance frequency (f ₀ ), and low-frequency reproduction is insufficient.

  The present invention has been made in view of the above, and can prevent complication of the manufacturing process of the speaker, and can obtain excellent moisture resistance, water resistance, heat resistance, light weight, moldability, and sound quality characteristics. It aims at providing the manufacturing method of the film for diaphragms of a speaker.

As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have completed the present invention, paying attention to the specific gravity (or density), heat resistance, and elastic modulus of the polyamide 9T resin film. That is, in order to solve the above problems in the present invention, a manufacturing method for forming a diaphragm film for a speaker by a melt extrusion method using a polyamide 9T resin-containing molding material,
A molding material containing polyamide 9T resin is melt-kneaded, and using this molding material, a diaphragm film for a speaker is continuously extruded from a die of an extrusion molding machine, and the extruded diaphragm film is bonded to a pressure roll and a cooling roll. And the characteristics of the diaphragm film after cooling are set to a specific gravity of 1.1 to 1.2, a tensile elastic modulus of 1500 to 2800 N / mm ² , and a thickness of 3 to 100 μm. It is said.

  The polyamide 9T resin has an intrinsic viscosity measured in concentrated sulfuric acid at 30 ° C. of 0.4 to 3.0 dl / g, the moisture content before melt kneading of the polyamide 9T resin is 5000 ppm or less, and contains this polyamide 9T resin. The molding material can be put into an extruder while supplying an inert gas.

  Here, it is preferable that 60-100 mol% of the dicarboxylic acid component of the polyamide 9T resin in the claims is terephthalic acid. The polyamide 9T resin is preferably a resin in which 10% or more of the end groups of the molecular chain are sealed with a monocarboxylic acid end-capping agent. Moreover, the number of press-bonding rolls and cooling rolls can be increased or decreased as necessary.

  At the downstream side of the pressure roll, a winder for the diaphragm film is installed, and between these pressure roll and the winder, a slit blade that forms a slit on the side of the diaphragm film is disposed, Between the slit blade and the winder, a tension roll for applying tension to the diaphragm film can be rotatably supported. The speaker according to the present invention is used in various electronic devices including at least a mobile phone, a smartphone, a portable music device, a portable game machine, a tablet personal computer, and the like.

According to the present invention, since the specific gravity of the diaphragm film after cooling is in the range of 1.1 to 1.2, the density can be reduced and good sound quality characteristics can be obtained. Moreover, since the tensile elastic modulus of the diaphragm film is in the range of 1500 to 2800 N / mm ² , the high frequency resonance frequency (f _H ) of the diaphragm becomes lower than necessary, and the minimum resonance frequency (f ₀ ) becomes higher. As a result, it is possible to suppress the sound reproduction characteristics from becoming insufficient. Furthermore, since the thickness of the diaphragm film is in the range of 3 to 100 μm, the mechanical strength of the diaphragm film can be remarkably lowered and the molding accuracy can be prevented from being lowered.

According to the present invention, the characteristics of the diaphragm film after cooling have a specific gravity of 1.1 to 1.2, a tensile elastic modulus of 1500 to 2800 N / mm ² and a thickness of 3 to 100 μm. There is an effect that complications can be prevented. Further, there is an effect that excellent moisture resistance, water resistance, heat resistance, light weight, moldability, and sound quality characteristics can be obtained.

  According to the invention described in claim 2, since the intrinsic viscosity of polyamide 9T resin measured in concentrated sulfuric acid at 30 ° C. is in the range of 0.4 to 3.0 dl / g, the moldability of the film is improved, and the machine A diaphragm film excellent in mechanical properties and heat resistance can be obtained. In addition, since the moisture content before melt kneading of the polyamide 9T resin is set to 5000 ppm or less, it is possible to eliminate the possibility that the polyamide 9T resin foams during the production of the diaphragm film. Furthermore, since a molding material containing polyamide 9T resin is introduced while supplying an inert gas, and melted and kneaded by an extrusion molding machine, it is possible to prevent the molding material from being deteriorated by oxidation, oxygen crosslinking, or the like. become.

It is a whole explanatory view showing typically an embodiment of a manufacturing method of a film for a diaphragm of a speaker concerning the present invention.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. A method for manufacturing a film for a speaker diaphragm in this embodiment includes a molding material 2 containing polyamide 9T resin as shown in FIG. Melting and kneading, and using this molding material 2, the diaphragm film 1 having an appropriate elastic modulus is extruded from the T die 13 of the melt extrusion molding machine 10, and the diaphragm film 1 is placed between the pressure roll 16 and the cooling roll 17. The characteristics of the diaphragm film 1 are such that the specific gravity is 1.1 to 1.2, the tensile modulus is 1500 to 2800 N / mm ² , and the thickness is 3 to 100 μm.

  Polyamide 9T resin is composed of a dicarboxylic acid component in which 60 to 100 mol% of the dicarboxylic acid component is terephthalic acid, 60 to 100 mol% of the diamino acid component, and 1,9-nonanediamine and 2-methyl-1,8-octane. It is a polyamide resin comprising a diamine component selected from diamines, and has a melting point in the range of 260 to 350 ° C, generally around 300 ° C.

  As the dicarboxylic acid component of the polyamide 9T resin, terephthalic acid is used. The amount of terephthalic acid used is 60 mol% or more, preferably 75 mol% or more, more preferably 90 mol% or more, based on the entire dicarboxylic acid component. This is because, when the terephthalic acid component is less than 60 mol%, various physical properties such as heat resistance, low water absorption, and chemical resistance of the obtained diaphragm film 1 are lowered.

  As other dicarboxylic acid components other than the terephthalic acid component, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, Aliphatic dicarboxylic acids such as 3,3-diethylsuccinic acid, azelaic acid, sebacic acid and suberic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, 4,4 '-Oxydibenzoic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4' Dicarboxylic acids, aromatic dicarboxylic acids such as 4,4'-biphenyl dicarboxylic acid or any mixture thereof.

  Of these, aromatic dicarboxylic acids are preferably used. In addition, polyvalent carboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid are used as long as melt molding is possible.

  As the diamine component of the polyamide 9T resin, a diamine selected from 1,9-nonanediamine and 2-methyl-1,8-octanediamine is used. The amount of the diamine used is 60 mol% or more, preferably 70 mol% or more, more preferably 80 mol% or more with respect to the entire diamine component. By using a diamine selected from the above amounts of 1,9-nonanediamine and 2-methyl-1,8-octanediamine as the diamine component, heat resistance, chemical resistance, low water absorption, light weight, sliding property A polyamide resin having excellent properties, mechanical properties, and moldability can be obtained.

  The molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is preferably 50:50 to 99: 1, more preferably 60:40 to 90:10. This is because a film particularly excellent in heat resistance and low water absorption can be obtained by using 1,9-nonanediamine and 2-methyl-1,8-octanediamine together in the above molar ratio.

  As other diamine components other than the above, ethylenediamine, propylenediamine, 1,4-butanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,10-decanediamine, 1,12-dodecanediamine, 3-methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 5-methyl-1,9-nonanediamine Aliphatic amines such as cyclohexanediamine, methylcyclohexanediamine, and isophoronediamine; p-phenylenediamine, m-phenylenediamine, xylenediamine, 4,4′-diaminodiphenylsulfone, 4,4′-diamino Aromatic diamino such as diphenyl ether, or any of these Mixtures thereof.

  In the polyamide 9T resin, 10% or more, preferably 40% or more, more preferably 70% or more of the end groups of the molecular chain may be sealed with an end-capping agent. This is because the end-sealing improves the viscosity stability of the diaphragm film 1 during melt molding, and the diaphragm film 1 having excellent hot water resistance and surface appearance can be obtained.

  The end-capping agent is not particularly limited as long as it is a monofunctional compound having reactivity with the amino group or carboxyl group of the polyamide end group, and is monocarboxylic acid, monoamine, acid anhydride, monoisocyanate, monoacid halogen. Compounds, monoesters, monoalcohols and the like can be used. Of these, monocarboxylic acids or monoamines are preferable from the viewpoints of reactivity and stability of the capped end, and monocarboxylic acids are most suitable from the viewpoint of ease of handling.

  The monocarboxylic acid used as the end-capping agent is not particularly limited as long as it has reactivity with an amino acid. For example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, Aliphatic monocarboxylic acids such as tridecylic acid, myristic acid, threlic acid, pivalic acid and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid Examples include acids, aromatic monocarboxylic acids such as methyl naphthalene carboxylic acid and phenyl acetic acid, or any mixture thereof.

  Of these, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid from the viewpoints of reactivity, stability of the sealing end, price, etc. Benzoic acid is particularly preferred.

  The amino acid used as the end-capping agent is not particularly limited as long as it has reactivity with a monocarboxylic acid. For example, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, Aliphatic monoamines such as stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic amines such as aniline, toluidine, diphenylamine, and aftylamine, or any of these Applicable to mixtures.

  Of these, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline are the most suitable from the viewpoints of reactivity, boiling point, stability of the sealing end, and price.

  The polyamide 9T resin is usually used in a form suitable for molding such as powder, granule, pellet and the like. In addition, for the polyamide 9T resin, stabilizers (copper compounds, etc.), colorants (titanium oxide, carbon black, etc.), ultraviolet absorbers, light stabilizers, antioxidants (hindered phenols, hindered amines) are necessary. Thio, phosphorus, etc.), antistatic agent, bromine polymer, flame retardant (antimony oxide, metal hydroxide, etc.), crystal nucleating agent (talc, calcium carbonate, silica, alumina, etc.), plasticizer, mold release Agent, lubricant (silicone, fluorine, etc.), inorganic filler, organic filler (graphite, carbon nanotube, graphene, fullerene, etc.), inorganic fiber (potassium titanate whisker, aluminum borate whisker, etc.), organic fiber Additives such as (aramid fiber, carbon fiber, etc.) are added during or after the synthesis of the polyamide 9T resin. These additives may be surface-treated with a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, or the like as necessary.

  The intrinsic viscosity [η] of polyamide 9T resin measured in concentrated sulfuric acid at 30 ° C. is in the range of 0.4 to 3.0 dl / g, preferably in the range of 0.6 to 2.0 dl / g, more preferably The range of 0.8-1.8 dl / g is good. This is because if the intrinsic viscosity [η] is within the range, the film moldability is improved, and the diaphragm film 1 having excellent mechanical properties, heat resistance, and the like can be obtained.

  As a method for producing such a polyamide 9T resin, for example, the production methods described in JP-A-7-228689, JP-A-7-228769, JP-A-7-228772, JP-A-7-228774, etc. can give. As a specific example of this polyamide 9T resin, for example, Genesta (product name, manufactured by Kuraray Co., Ltd.) can be mentioned.

  Other polyamide resins and thermoplastic resins are selectively added to the molding material 2 containing the polyamide 9T resin as long as the effects of the present invention are not impaired. Other polyamide resins include polyamide 6T resin, modified polyamide 6T resin, semi-aromatic polyamide resin such as polyamide 10T resin and polyamide 11T resin, or fat such as polyamide 6 resin, polyamide 66 resin, polyamide 12 resin and polyamide 46 resin. Group polyamide resin.

  Other thermoplastic resins include polyethylene resins, polypropylene resins, polyolefin resins such as polymethylpentene resins, thermoplastic elastomers of olefin resins modified with dicarboxylic acid and / or derivatives thereof, polyimide resins, polyamideimide resins and polyethers. Polyimide resins such as imide resins, polyarylene ketone resins such as polyether ether ketone resins and polyether ketone resins, polysulfone resins, sulfone resins such as polyether sulfone resins and polyphenylene sulfone resins, polyphenylene sulfide resins, etc. Polyarylene sulfide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyester resin such as polyethylene naphthalate resin and polybutylene naphthalate resin, poly Tetrafluoroethylene resin, tetrafurfuryl Oto ethylene - perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene - hexafluoropropylene copolymer, tetrafluoroethylene - fluorocarbon resins such as ethylene copolymers, liquid crystal polymers, and the like. The liquid crystal polymer may be any of type I, type II, and type III.

  When manufacturing the speaker diaphragm film 1 using the molding material 2 containing the polyamide 9T resin, a known manufacturing method such as a melt extrusion molding method, a calendar molding method, or a casting molding method may be employed. it can. However, from the viewpoints of improving the thickness accuracy, productivity, and handling properties of the diaphragm film 1 and simplifying the equipment, it is preferable to continuously extrude thinly by a melt extrusion method.

  Here, as shown in FIG. 1, the melt extrusion molding method uses a melt extrusion molding machine 10 to melt and knead the molding material 2, and from the T die 13 at the front end of the melt extrusion molding machine 10 to the diaphragm film This is a method of continuously extruding 1.

  The melt extrusion molding machine 10 includes, for example, a single screw extrusion molding machine or a twin screw extrusion molding machine, and functions to melt and knead the molding material 2 that has been charged. A raw material inlet 11 for the molding material 2 is installed at the upper rear of the melt extrusion molding machine 10. The raw material inlet 11 has helium gas, neon gas, argon gas, krypton gas, nitrogen gas, carbon dioxide gas. An inert gas supply pipe 12 that supplies an inert gas such as an arrow (see the arrow in FIG. 1) as necessary is connected. The flow of the inert gas through the inert gas supply pipe 12 causes the molding material 2 to flow. Oxidation degradation and oxygen crosslinking are effectively prevented.

  The temperature at the time of melt kneading of the melt extrusion molding machine 10 is adjusted to the melting point of the polyamide 9T resin to 370 ° C, preferably 310 ° C to 350 ° C. This is because if the polyamide 9T resin is less than the melting point, the polyamide 9T resin-containing molding material 2 cannot be melt-extruded, and conversely if it exceeds 370 ° C., the polyamide 9T resin may be decomposed. Based on the reason that there is.

  The T-die 13 is attached to the tip of the melt extrusion molding machine 10 via a connecting pipe 14 and functions to continuously extrude the thin band-shaped diaphragm film 1 downward. A gear pump 15 mounted on the connecting pipe 14 is located upstream of the T die 13, and the gear pump 15 transfers the molding material 2 to the T die 13 at a constant speed and with high accuracy. The temperature during extrusion of the T die 13 is adjusted to the melting point of the polyamide 9T resin to 370 ° C., preferably 310 ° C. to 350 ° C. This is based on the reason that when the melting point of the polyamide 9T resin is lower than the melting point of the molding material 2, it becomes difficult to melt-extrude the molding material 2, and when it exceeds 370 ° C., the polyamide 9T resin may be decomposed.

  A pair of crimping rolls 16 is pivotally supported below the T-die 13 so as to sandwich the cooling roll 17. Of the pair of crimping rolls 16, a winding tube 19 of a winder 18 that winds up the diaphragm film 1 is rotatably installed downstream of the downstream crimping roll 16. A slit blade 20 that forms a slit in the side portion of the diaphragm film 1 is disposed so as to be movable up and down between the 18 winding tubes 19, and the slit blade 20 and the winding tube of the winding machine 18. A required number of rotatable tension rolls 21 for supporting the diaphragm film 1 to be smoothly wound up by applying tension to the diaphragm film 1 are supported between the two.

  From the viewpoint of improving the adhesion between the diaphragm film 1 and the cooling roll 17, at least the natural rubber, the isoprene rubber, the butadiene rubber, the norbornene rubber, the acrylonitrile butadiene rubber, the nitrile rubber, and the urethane are provided on the peripheral surface of each pressure roll 16. A rubber layer such as rubber, silicone rubber, or fluorine rubber is coated as necessary, and an inorganic compound such as silica or alumina is selectively added to the rubber layer. Among these, it is preferable to employ silicone rubber or fluororubber having excellent heat resistance.

  As the pressure-bonding roll 16, a metal elastic roll having a metal surface is used as necessary. When this metal elastic roll is used, the diaphragm film 1 having a smooth surface can be formed. . Specific examples of the metal elastic roll include a metal sleeve roll, an air roll (a product name manufactured by Dimco), and a UF roll (a product name manufactured by Hitachi Zosen).

  Such a pressure roll 16 is adjusted to a temperature of 230 ° C. or lower, preferably 200 ° C. or lower, more preferably 50 ° C. to 180 ° C., and is slidably contacted with the diaphragm film 1 and pressed against the cooling roll 17. The range of the temperature of the pressure roll 16 is that when the temperature of the pressure roll 16 exceeds 230 ° C., the diaphragm film 1 is adhered to the pressure roll 16 during the production of the diaphragm film 1, and the diaphragm film This is because 1 may be broken. Conversely, when the temperature is lower than 50 ° C., the thickness accuracy of the diaphragm film 1 is lowered.

  The cooling roll 17 is made of, for example, a metal roll having a diameter larger than that of the pressure-bonding roll 16, and sandwiches the diaphragm film 1, which is rotatably supported below the T-die 13 and is pressed between the pressure-rolling rolls 16. The diaphragm film 1 functions together with the pressure roll 16 while cooling the diaphragm film 1 within a predetermined range. The cooling roll 17 is adjusted to a temperature of 230 ° C. or less, preferably 200 ° C. or less, more preferably 50 ° C. to 180 ° C., and is in sliding contact with the diaphragm film 1, similarly to the press roll 16. This is because if the temperature of the cooling roll 17 exceeds 230 ° C., the diaphragm film 1 may stick to the cooling roll 17 during the production of the diaphragm film 1 and break.

  In the above, when the diaphragm film 1 is manufactured, as shown in FIG. 1, the molding material 2 is fed into the raw material inlet 11 of the melt extrusion molding machine 10 while supplying the inert gas indicated by the arrow in FIG. Then, the molding material 2 is melted and kneaded in a heated and pressurized state by the melt extrusion molding machine 10, and the belt-shaped diaphragm film 1 is continuously extruded from the T die 13. At this time, the moisture content of the polyamide 9T resin before melt-kneading is adjusted to 5000 ppm or less, preferably 2000 ppm or less, more preferably 250 to 2000 ppm or less. This is based on the reason that the polyamide 9T resin may foam when the water content before the melt kneading of the polyamide 9T resin exceeds 5000 ppm.

  When the diaphragm film 1 is extruded, the diaphragm film 1 is wound around the winding tube 19 of the pair of pressure roll 16, the cooling roll 17, the tension roll 21, and the winder 18, and the diaphragm film 1 is cooled by the cooling roll 17. If both sides of the diaphragm film 1 are cut with the slit blades 20 and wound around the winding tube 19 in sequence, the diaphragm film 1 made of polyamide 9T resin can be manufactured.

  Fine irregularities can be formed on the surface of the diaphragm film 1 as long as the effects of the present invention are not lost, and the friction coefficient of the surface of the diaphragm film 1 can be reduced. For example, (1) a polyamide 9T resin is melt-kneaded by a melt extrusion molding machine 10, and the melt-kneaded polyamide 9T resin is transferred from a T die 13 to a cooling roll having fine unevenness on the peripheral surface. A method of discharging and adhering onto the diaphragm 17 to form fine irregularities at the same time when the diaphragm film 1 is formed; (2) on the cooling roll 17 having fine irregularities on the peripheral surface after the diaphragm film 1 is manufactured; There is a method for forming fine irregularities by closely adhering to the substrate. Either method can be adopted, but from the viewpoint of simplification of equipment, the method (1) is preferable.

  The specific gravity of the diaphragm film 1 after cooling is optimally 1.1 to 1.2, preferably 1.12 to 1.18, more preferably 1.12 to 1.16. This is based on the reason that, within such a range, the density is small and the weight can be reduced, and good sound quality characteristics can be obtained.

The tensile modulus of the diaphragm film 1 after cooling is optimally in the range of 1500-2800 N / mm ² , preferably 1800-2500 N / mm ² , and more preferably 2000-2500 N / mm ² . This is because, when the tensile elastic modulus of the diaphragm film 1 is less than 1500 N / mm ² , the high frequency resonance frequency (f _H ) of the diaphragm made of the diaphragm film 1 is low, and high-frequency sound reproduction becomes insufficient. Because. Further, if it exceeds 2800 N / mm ² , the minimum resonance frequency (f ₀ ) of the diaphragm obtained from the film is high, and low-frequency reproduction is insufficient.

  Moreover, the thickness of the film 1 for diaphragms after cooling is 3-100 micrometers, Preferably it is 5-95 micrometers, More preferably, the range of 8-90 micrometers is suitable. This is because when the thickness of the diaphragm film 1 is less than 3 μm, the mechanical strength of the film is remarkably lowered, so that it is difficult to form the diaphragm film 1. On the contrary, when the thickness of the diaphragm film 1 exceeds 100 μm, the molding accuracy to the diaphragm is lowered. The thickness of the diaphragm film 1 can be measured with various micrometers.

  The thickness tolerance of the diaphragm film 1 is preferably within an average value ± 5%, and more preferably within an average value ± 3%. This is because if the thickness tolerance of the diaphragm film 1 is out of the range of the average value ± 5%, the sound quality varies, which is not preferable. The thickness tolerance of the diaphragm film 1 can be obtained by a predetermined formula.

According to the above, since the diaphragm is not made of metal foil, the lowest resonance frequency (f ₀ ) can be lowered and sufficient reproduction characteristics with low sound can be obtained. Further, since the diaphragm is not natural resin paper, woven fabric, or non-woven fabric, excellent moisture resistance, water resistance, and heat resistance can be obtained, and simplification and simplification of the speaker manufacturing process can be achieved. be able to. In addition, since a film made of polyamide 9T resin having an appropriate tensile elastic modulus is excellent in low sound reproduction and high sound reproduction, it is possible to obtain an excellent speaker diaphragm. Further, since the film made of polyamide 9T resin has a small specific gravity, it is possible to obtain a diaphragm for a speaker that is light in weight and excellent in heat resistance.

  In addition, on the surface of the diaphragm film 1 in the above embodiment, various antistatic agents, silicone resins, acrylic resins, urethane resins and other elastomers can be applied within a range not losing the effects of the present invention, aluminum, Various metals such as tin, nickel, and copper may be deposited.

  Examples of the method for manufacturing a diaphragm film for a speaker according to the present invention will be described below together with comparative examples.

[Example 1]
First, a commercially available polyamide 9T resin (product name: Genesta N1000A-M42 NATURAL) prepared as a molding material was prepared, and this polyamide 9T resin was dried for 12 hours in a dehumidifying dryer heated to 115 ° C., and the dried polyamide The 9T resin is set in a φ40 mm single screw extruder equipped with a T die having a width of 900 mm, melt kneaded, and this melt kneaded polyamide 9T resin is continuously extruded from the T die of the single screw extruder to vibrate the diaphragm. A polyamide 9T resin film, which is a film for use, was extruded into a strip shape.

  At this time, the moisture content of the polyamide 9T resin was measured by a Karl Fischer titration method using a trace moisture measuring device (product name CA-100 manufactured by Mitsubishi Chemical Corporation). As a result of the measurement, the moisture content during drying of the polyamide 9T resin was 286 ppm. The single screw extruder was L / D = 32, compression ratio: 2.5, screw: full flight screw type. The temperature of the single screw extruder was adjusted to 230 to 350 ° C., the temperature of the T die was adjusted to 315 to 320 ° C., and the temperature of the connecting pipe connecting the single screw extruder and the T die was adjusted to 315 ° C.

  Regarding the temperature of the melted polyamide 9T resin, the resin temperature at the inlet of the T die was measured, and the measured temperature was 318 ° C. Further, when the polyamide 9T resin was charged into the single screw extruder, nitrogen gas 18 L / min was supplied.

  When the polyamide 9T resin film is extrusion-molded in this way, both sides of the continuous polyamide 9T resin film are cut with a slit blade and sequentially wound on a winding tube of a winder, and a polyamide 9T resin film having a length of 100 m and a width of 620 mm is obtained. Manufactured. At this time, the polyamide 9T resin film is successively applied to a pair of pressure-bonding rolls made of silicone rubber, a metal roll which is a 180 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding tube located downstream of these. It was wound and sandwiched between a pressure roll and a metal roll.

  When a polyamide 9T resin film as a diaphragm film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus, and heat resistance of this polyamide 9T resin film were evaluated, and the results are shown in Table 1. About heat resistance, it evaluated by the storage elastic modulus in 250 degreeC.

-Film thickness of the polyamide 9T resin film The thickness of the polyamide 9T resin film was measured using a micrometer (product name: coolant proof micrometer code MDC-25PJ, manufactured by Mitutoyo Corporation). In the measurement, the thickness of a predetermined position where the extrusion direction and the width direction (the direction perpendicular to the extrusion direction) of the polyamide 9T resin film intersect was measured at 100 locations, and the average value was taken as the film thickness. The measurement locations in the extrusion direction were 100 mm, 200 mm, 300 mm, 400 mm, and 500 mm at 100 mm intervals from the tip of the polyamide 9T resin film.

  On the other hand, the measurement location in the width direction is 25 mm from the left end of the polyamide 9T resin film, then 55 mm, 85 mm, 115 mm, 145 mm, 175 mm, 205 mm, 235 mm, 265 mm, 295 mm, 325 mm, 355 mm, 385 mm, 385 mm, 415 mm at 30 mm intervals. 445 mm, 475 mm, 505 mm, 535 mm, 565 mm, and 595 mm.

-Film thickness tolerance of polyamide 9T resin film About the film thickness tolerance of the polyamide 9T resin film, it calculated | required from the following formula | equation.
Film thickness tolerance [%] = {(MAX or MIN) − (AVE)} / (AVE) × 100
Where MAX: maximum value of film thickness
MIN: Minimum film thickness
AVE: Average value of film thickness A when the obtained film thickness tolerance was within ± 3%, B when within ± 3 to 5%, and NG when over ± 5%.

-Specific gravity of the polyamide 9T resin film The specific gravity of the polyamide 9T resin film was measured under the condition of a temperature of 23 ° C in accordance with the measuring method of JIS K7112 (Method A).

-Tensile elastic modulus of polyamide 9T resin film The tensile elastic modulus of the polyamide 9T resin film was measured in accordance with JIS K7127 (test piece type 1B) under the conditions of a tensile speed of 50 mm / min and a temperature of 23 ° C. The tensile modulus was measured in the film extrusion direction and the width direction (perpendicular to the extrusion direction).

-Storage elastic modulus of polyamide 9T resin film The heat resistance of the polyamide 9T resin film was evaluated by the storage elastic modulus. The storage modulus of the polyamide 9T resin film was measured in the extrusion direction and the width direction (perpendicular to the extrusion direction) of the polyamide 9T resin film.

  Specifically, when measuring the storage elastic modulus of the polyamide 9T resin film in the extrusion direction, the extrusion direction is 60 × 6 mm in the width direction, and when measuring the storage elastic modulus in the width direction, the size is 6 mm × 60 mm in the extrusion direction. Cut out and measured. In measuring the storage elastic modulus, a frequency mode of 3 Hz, a strain of 0.1%, and a rate of temperature increase by a tensile mode using a viscoelastic spectrometer (product name: RSA-G2 manufactured by TS Instruments Japan Co., Ltd.) Measurement was performed under the conditions of 3 ° C./min, a measurement temperature range of −60 to 320 ° C. and a check interval of 21 mm, and a storage elastic modulus at 250 ° C. was obtained.

[Example 2]
The polyamide 9T resin after drying used in Example 1 was extruded into a band-like polyamide 9T resin film as a diaphragm film using the same single screw extruder and T dice as in Example 1. The temperatures of the single screw extruder, the T die, and the connecting pipe connecting the single screw extruder and the T die were the same as those in Example 1. The temperature of the melted polyamide 9T resin was determined by measuring the resin temperature at the T-die inlet, and the measured temperature was 317 ° C.

  After the polyamide 9T resin film was extrusion-molded in this way, both sides of the continuous film were cut with a slit blade and wound up sequentially around a winding tube of a winder to produce a polyamide 9T resin film having a length of 100 m and a width of 620 mm. At this time, the polyamide 9T resin film is successively applied to a pair of pressure-bonding rolls made of silicone rubber, a metal roll which is a 180 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding tube located downstream of these. It was wound and sandwiched between a pressure roll and a metal roll.

  When a polyamide 9T resin film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus, and storage elastic modulus at 250 ° C. of this polyamide 9T resin film were measured, and the results are shown in Table 1.

Example 3
First, a commercially available polyamide 9T resin (product name: Genesta N1000A-M42 BLACK) manufactured as a molding material was dried for 12 hours in a dehumidifying dryer heated to 115 ° C., and this dried polyamide 9T resin was used as Example 1. Extrusion molding was performed on a strip-shaped polyamide 9T resin film by the same production method.

  At this time, the moisture content of the polyamide 9T resin was measured by the same method as in Example 1. As a result of the measurement, the moisture content when the polyamide 9T resin was dried was 291 ppm. Moreover, the temperature of the single screw extruder was adjusted to 230 to 340 ° C, the temperature of the T die was 310 to 320 ° C, and the temperature of the connecting pipe connecting the single screw extruder and the T die was adjusted to 315 ° C. Further, the temperature of the melted polyamide 9T resin was determined by measuring the resin temperature at the inlet of the T die, and the measured temperature was 314 ° C.

  When the polyamide 9T resin film was extruded, a polyamide 9T resin film having a length of 100 m and a width of 620 mm was produced in the same manner as in Example 1. The film thickness, film thickness tolerance, specific gravity, tensile elastic modulus of this polyamide 9T resin film, And the storage elastic modulus in 250 degreeC was measured, and the result was described in Table 1.

Example 4
Using the polyamide 9T resin after drying used in Example 3 and a single screw extruder similar to that used in Example 1 and a T die, a belt-shaped polyamide 9T resin film was extruded. The temperatures of the single-screw extruder, the T-die, and the connecting pipe that connects the single-screw extruder and the T-die were the same as those in Example 3. The temperature of the melted polyamide 9T resin was 311 ° C. when the resin temperature at the T-die inlet was measured.

  After the polyamide 9T resin film was extruded, both sides of the continuous film were cut with a slit blade and wound up sequentially around the winding tube of a winder to produce a polyamide 9T resin film having a length of 100 m and a width of 620 mm. At this time, the polyamide 9T resin film is sequentially applied to a pair of pressure-bonding rolls made of silicone rubber, a metal roll which is a 185 ° C. cooling roll having irregularities on the peripheral surface, and a 6-inch winding tube located downstream of these. It was wound and sandwiched between a pressure roll and a metal roll.

  When a polyamide 9T resin film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus, and storage elastic modulus at 250 ° C. of this polyamide 9T resin film were measured, and the results are shown in Table 1.

Example 5
Using the polyamide 9T resin after drying used in Example 3 and a single screw extruder similar to that used in Example 1 and a T die, a belt-shaped polyamide 9T resin film was extruded. The temperature of the single screw extruder, the T die, and the connecting pipe connecting the single screw extruder and the T die were the same as those in Example 3. The temperature of the molten polyamide 9T resin was 312 ° C. when the resin temperature at the T-die inlet was measured.

  After the polyamide 9T resin film was extrusion-molded, both sides of the continuous film were cut with a slit blade and sequentially wound around a winding tube of a winder to produce a polyamide 9T resin film having a length of 150 m and a width of 620 mm. At this time, the polyamide 9T resin film is sequentially applied to a pair of pressure-bonding rolls made of silicone rubber, a metal roll which is a 100 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding tube located downstream of these. It was wound and sandwiched between a pressure roll and a metal roll.

  When the polyamide 9T resin film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus, and storage elastic modulus at 250 ° C. of the polyamide 9T resin film were measured, and the results are shown in Table 2.

Example 6
First, a commercially available polyamide 9T resin (product name: Genesta TS-329, manufactured by Kuraray Co., Ltd.) was dried for 12 hours with a dehumidifying dryer heated to 115 ° C., and this dried polyamide 9T resin was uniaxially similar to Example 1. By using an extruder and a T-die, it was extruded into a band-shaped polyamide 9T resin film.

  At this time, the moisture content of the polyamide 9T resin was measured by the Karl Fischer titration method using a trace moisture measuring device (product name CA-100 manufactured by Mitsubishi Chemical Corporation). The moisture content when the polyamide 9T resin was dried was 255 ppm. Met. The temperature of the single screw extruder was adjusted to 230 to 350 ° C., the temperature of the T die was adjusted to 300 to 305 ° C., and the temperature of the connecting pipe connecting the single screw extruder and the T die was adjusted to 315 ° C.

  After the polyamide 9T resin film was extrusion-molded, both sides of the continuous film were cut with a slit blade and sequentially wound around a winding tube of a winder to produce a polyamide 9T resin film having a length of 150 m and a width of 620 mm. At this time, the polyamide 9T resin film is successively applied to a pair of pressure-bonding rolls made of silicone rubber, a metal roll which is a 180 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding tube located downstream of these. It was wound and sandwiched between a pressure roll and a metal roll.

  When a polyamide 9T resin film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus, and storage elastic modulus at 250 ° C. of this polyamide 9T resin film were measured, and the results are shown in Table 2.

Example 7
First, a commercially available polyamide 9T resin (product name: Genesta TS-364, manufactured by Kuraray Co., Ltd.) was dried for 12 hours with a dehumidifying dryer heated to 115 ° C., and this dried polyamide 9T resin was uniaxial as in Example 1. A belt-shaped polyamide 9T resin film was extruded by using an extruder and a T-die.

  At this time, the moisture content of the polyamide 9T resin was measured by a Karl Fischer titration method using a trace moisture measuring device (product name: CA-100 type, manufactured by Mitsubishi Chemical Corporation). It was 281 ppm. The temperature of the single screw extruder was adjusted to 230 to 330 ° C., the temperature of the T die was 310 to 315 ° C., and the temperature of the connecting pipe connecting the single screw extruder and the T die was adjusted to 310 ° C.

  After the polyamide 9T resin film was extruded, both sides of the continuous film were cut with a slit blade and wound up sequentially around the winding tube of a winder to produce a polyamide 9T resin film having a length of 100 m and a width of 620 mm. At this time, the polyamide 9T resin film is successively applied to a pair of pressure-bonding rolls made of silicone rubber, a metal roll which is a 180 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding tube located downstream of these. It was wound and sandwiched between a pressure roll and a metal roll.

  When a polyamide 9T resin film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus, and storage elastic modulus at 250 ° C. of this polyamide 9T resin film were measured, and the results are shown in Table 2.

[Comparative Example 1]
First, a commercially available polyetheretherketone resin (product name: VestaKeep 3300G, manufactured by Daicel-Evonik) was dried as a molding material for 12 hours in a dehumidifying dryer heated to 160 ° C., and the dried polyetheretherketone resin was used. By using the same single screw extruder and T dice as in Example 1, a band-shaped polyetheretherketone resin film as a diaphragm film was extruded.

  At this time, the moisture content of the polyetheretherketone resin was measured by a Karl Fischer titration method using a trace moisture measuring device (product name: CA-100 manufactured by Mitsubishi Chemical Corporation). As a result of the measurement, the water content of the polyetheretherketone resin was 159 ppm. The temperature of the single screw extruder was adjusted to 250 to 450 ° C., the temperature of the T die was adjusted to 400 ° C., and the temperature of the connecting pipe connecting the single screw extruder and the T die was adjusted to 400 ° C.

  Once the polyetheretherketone resin film is extruded, both sides of the continuous film are cut with a slit blade and wound into the winding tube of a winder in order to obtain a polyetheretherketone resin film having a length of 100 m and a width of 620 mm. Manufactured. At this time, the polyether ether ketone resin film is composed of a pair of pressure-bonding rolls made of silicone rubber, a metal roll that is a 210 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding tube located downstream of these rolls. Were sequentially wound and sandwiched between a crimping roll and a metal roll.

  When the polyether ether ketone resin film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus, and storage elastic modulus at 250 ° C. of this polyether ether ketone resin film were measured, and the results are shown in Table 3. did.

[Comparative Example 2]
First, a commercially available polyetherimide resin (product name: ULTEM CRS5001-1000-NB, manufactured by SABIC Innovative Plastics) was dried for 12 hours in a dehumidifying dryer heated to 150 ° C., and this dried polyetherimide resin was used as an example. 1 was used to extrude a belt-shaped polyetherimide resin film as a diaphragm film.

  At this time, when the moisture content of the polyetherimide resin was measured by the Karl Fischer titration method using a trace moisture measuring device (product name: Model CA-100 manufactured by Mitsubishi Chemical Corporation), the moisture content of the polyetherimide resin was 229 ppm. Met. The temperature of the single screw extruder was adjusted to 230 to 390 ° C., the temperature of the T die was adjusted to 380 to 385 ° C., and the temperature of the connecting pipe connecting the single screw extruder and the T die was adjusted to 390 ° C.

  After the polyetherimide resin film was extruded, both sides of the continuous film were cut with a slit blade and wound up sequentially around the winding tube of a winder to produce a polyetherimide resin film having a length of 100 m and a width of 620 mm. . At this time, the polyetherimide resin film is applied to a pair of pressure-bonding rolls made of silicone rubber, a metal roll which is a 220 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding tube located downstream thereof. It wound around sequentially and was pinched | interposed into the crimping | compression-bonding roll and the metal roll.

  When a polyetherimide resin film was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus and storage elastic modulus at 250 ° C. of this polyetherimide resin film were measured, and the results are shown in Table 3.

[Comparative Example 3]
First, in order to prepare a molding material, the polyamide 9T resin used in Example 1 was pulverized by a freeze pulverization method. When the particle size distribution of the pulverized polyamide 9T resin was measured by an air jet sieve standard sieve, the 48 mesh pass was 96%.

  When the polyamide 9T resin is pulverized in this way, 30 parts by mass of talc is added to 100 parts by mass of the polyamide 9T resin and commercial talc (manufactured by Nippon Talc, product name: MS-P) in a resin container. In addition, a φ10 mm zirconia ball is put in a resin container, and a lid is attached to the resin container and attached to a tumbler mixer. The tumbler mixer is rotated at 23 ° C. for 1 hour to obtain polyamide 9T resin and talc. The zirconia balls were dispersed and mixed, and then the zirconia balls were taken out to prepare a stirring mixture.

  After the polyamide 9T resin and talc are dispersed and mixed to prepare a stirring mixture, the stirring mixture is supplied to a high-speed twin-screw extruder equipped with a vacuum pump and melt-kneaded under reduced pressure. It was extruded from a part die into a rod shape, cut after water cooling, dried in a dehumidifying dryer heated to 115 ° C. for 12 hours, cooled to room temperature after drying, and a pellet shape having a length of 4 to 7 mm and a diameter of 2 to 4 mm A molding material was prepared. The stirred mixture was melt-kneaded under conditions of a cylinder temperature of 330 to 350 ° C, an adapter temperature of 350 ° C, and a die temperature of 350 ° C.

  Next, the molding material is dried in a dehumidifying dryer heated to 115 ° C. for 12 hours, and the dried molding material is set in a φ40 mm single screw extruder equipped with a T die having a width of 900 mm, and melt-kneaded. The kneaded molding material was continuously extruded from a T-die of a single screw extruder, and a polyamide 9T resin film containing talc was extruded into a band shape.

  At this time, the moisture content of the molding material was measured by a Karl Fischer titration method using a trace moisture measuring device (product name CA-100 manufactured by Mitsubishi Chemical Corporation). As a result of the measurement, the moisture content when the molding material was dried was 307 ppm. The single screw extruder was L / D = 32, compression ratio: 2.5, screw: full flight screw type. The temperature of the single screw extruder was adjusted to 230 to 350 ° C., the temperature of the T die was adjusted to 315 to 320 ° C., and the temperature of the connecting pipe connecting the single screw extruder and the T die was adjusted to 315 ° C.

  Regarding the temperature of the molten molding material, the resin temperature at the inlet of the T die was measured, and the measured temperature was 334 ° C. Further, when charging the molding material into the single screw extruder, nitrogen gas of 18 L / min was supplied.

  After extruding a polyamide 9T resin film containing talc, both sides of the continuous film are cut with a slit blade and wound into a winding tube of a winder, and the diaphragm film has a length of 100 m and a width of 620 mm. A polyamide 9T resin film was produced. At this time, the polyamide 9T resin film containing talc is composed of a pair of pressure-bonding rolls made of silicone rubber, a metal roll that is a 180 ° C. cooling roll with irregularities on the peripheral surface, and a 6-inch winding located downstream thereof. The tube was wound around the tube one after another and sandwiched between a crimping roll and a metal roll.

  When a polyamide 9T resin film containing talc was obtained, the film thickness, film thickness tolerance, specific gravity, tensile elastic modulus and heat resistance of this polyamide 9T resin film were evaluated, and the results are shown in Table 3. About heat resistance, it evaluated by the storage elastic modulus in 250 degreeC.

[Result]
The polyamide 9T resin film obtained by the examples has a smaller specific gravity than the polyether ether ketone resin film of Comparative Example 1, the polyetherimide resin film of Comparative Example 2, and the polyamide 9T resin film of Comparative Example 3. Is lightweight. Therefore, when the polyamide 9T resin film of an Example is employ | adopted as a film for diaphragms, it is estimated that it is excellent in the acoustic radiation sound pressure level maintenance effect.

Moreover, the elasticity modulus of the polyamide 9T resin film of an Example has a moderate tensile elasticity modulus with 1800-2700N / mm < ² > unlike the comparative example. Therefore, when the polyamide 9T resin film of the example is employed as a film for a diaphragm, it is presumed that bass reproduction characteristics and treble reproduction are particularly excellent. On the other hand, in the case of Comparative Examples 1 and 3, since the tensile elastic modulus exceeds 3000 N / mm ² , it is estimated that the bass reproduction characteristics are insufficient.

Furthermore, the storage elastic modulus at 250 ° C. of the polyamide 9T resin film of the example was 1.0 × 10 ⁸ Pa or more, which was superior to the polyetherimide resin, unlike the comparative example. Therefore, the film of the example obtained from the polyamide 9T resin is light and has an appropriate tensile elastic modulus. Therefore, when it is adopted as a film for a diaphragm, it is assumed that it has excellent sound quality characteristics in addition to heat resistance. Is done.

  The method for manufacturing a speaker diaphragm film according to the present invention is used in the field of manufacturing audio equipment.

DESCRIPTION OF SYMBOLS 1 Film for diaphragm 2 Molding material 10 Melt extrusion molding machine (extrusion molding machine)
13 T Dice (Dice)
16 Pressure roll 17 Cooling roll 18 Winding machine 19 Winding pipe

Claims (2)

A manufacturing method for forming a diaphragm film for a speaker by a melt extrusion molding method using a polyamide 9T resin-containing molding material,
A molding material containing polyamide 9T resin is melt-kneaded, and using this molding material, a diaphragm film for a speaker is continuously extruded from a die of an extrusion molding machine, and the extruded diaphragm film is bonded to a pressure roll and a cooling roll. And the characteristics of the diaphragm film after cooling are set to a specific gravity of 1.1 to 1.2, a tensile elastic modulus of 1500 to 2800 N / mm ² , and a thickness of 3 to 100 μm. A method for manufacturing a film for a diaphragm of a speaker.   Molding material containing polyamide 9T resin having an intrinsic viscosity measured in concentrated sulfuric acid at 30 ° C. of 0.4 to 3.0 dl / g and a moisture content of 5000 ppm or less before melt kneading of polyamide 9T resin. The method for producing a film for a speaker diaphragm according to claim 1, wherein an inert gas is supplied to an extrusion molding machine.

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