JP7320429B2 - RESIN FILM FOR DIAPHRAGM OF PORTABLE DEVICE SPEAKER AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Description

TECHNICAL FIELD The present invention relates to a resin film for a diaphragm of a mobile device speaker used in a mobile phone, a mobile game device, a smart phone, etc., and a method for producing the same.

Portable devices such as mobile phones and smartphones have a built-in small speaker called a micro speaker. This diaphragm is manufactured using various materials such as metal foil, paper, and woven fabric. often

Conventional resin films for diaphragms of mobile device speakers include polyolefin resins such as polyethylene (PE) resin and polypropylene (PP) resin, polyester resins such as polyethylene terephthalate (PET) resin and polyethylene naphthalate (PEN) resin, It is molded from polyphenylene sulfide (PPS) resin, polyetherimide (PEI) resin, polyetheretherketone (PEEK) resin, or the like (see Patent Documents 1, 2, 3, and 4).

Further, in recent years, in order to ensure high strength, heat resistance, etc., use of crystalline thermoplastic polyimide (PI) resin has been proposed. In this case, the resin film for the diaphragm of the portable device speaker is formed into a belt-shaped thin film from a crystalline thermoplastic polyimide resin, cooled and wound on a winding machine, and then unwound to form the speaker of the portable device. It is secondary processed for use (see Patent Document 5).

JP-A-60-139098 JP 2019-054534 A JP 2018-191069 A JP 2018-064150 A JP 2018-042043 A

Conventional resin films for diaphragms of mobile device speakers are formed as described above, and when molded from a crystalline thermoplastic polyimide resin, they are excellent in high strength, high heat resistance, high solvent resistance, etc., but are not sufficient. Since it is not possible to obtain sufficient slipperiness, wrinkles may occur when it is wound on a winding machine during production. As a result, there arises a problem that the diaphragm resin film is broken or damaged during manufacturing or secondary processing.

As a method for solving this problem, a method has been proposed in which a tetrafluoroethylene/perfluoroethylene copolymer resin is added to a crystalline thermoplastic polyimide resin to improve the slipperiness. In the case of this method, the resin film obtained from the mixture of the crystalline thermoplastic polyimide resin and the tetrafluoroethylene/perfluoroalkoxyethylene copolymer resin is sufficiently improved in slipperiness as initially expected.

However, a resin film obtained from a mixture of a crystalline thermoplastic polyimide resin and a tetrafluoroethylene/perfluoroalkoxyethylene copolymer is a crystalline thermoplastic polyimide resin and a tetrafluoroethylene/perfluoroalkoxyethylene copolymer. It has poor compatibility with polymer resins, and its mechanical strength decreases. Therefore, if the external output is increased and used at high volume for a long time, the durability deteriorates, such as deformation or breakage of the diaphragm of the speaker of a mobile device. A new big problem arises.

In addition, when the diaphragm resin film is formed of a crystalline thermoplastic polyimide resin, it has a low elastic modulus, so the bass resonance frequency (F ₀ ) is low. It is possible to obtain sufficient low-frequency characteristics. However, a diaphragm resin film made of a crystalline thermoplastic polyimide resin has a small loss tangent (= loss elastic modulus/storage elastic modulus, or tan δ). is difficult. Furthermore, since the crystalline thermoplastic polyimide resin film is inferior in slipperiness between the resin films, wrinkles may occur when the film is wound on a winder, resulting in deterioration of quality.

The present invention has been devised in view of the above, and even if molded from a crystalline thermoplastic polyimide resin, improvement in lubricity can be expected, and the increase in loss tangent suppresses the occurrence of resonance, resulting in a favorable performance. An object of the present invention is to provide a resin film for a diaphragm of a loudspeaker of a mobile device and a method for manufacturing the same, which can obtain sound quality.

In order to achieve the above object, the present inventors have made intensive studies and, as a result, have focused on the combination of a crystalline thermoplastic polyimide resin and an adhesive fluororesin, and completed the present invention.

That is, in order to solve the above problems in the present invention, a thermoplastic polyimide is molded from a molding material containing 100 parts by mass of a crystalline thermoplastic polyimide resin and 1 part by mass or more and 100 parts by mass or less of an adhesive fluororesin. The resin is prepared from at least a tetracarboxylic component and a diamine component whose main component is an aliphatic diamine, and the apparent shear viscosity of the adhesive fluororesin at 350° C. is 9×10 ² Pa· at a load of 50 kgf. s or more and 2×10 ⁴ Pa·s or less,
52 N/mm ² or more and 68 N/mm ² or less when the maximum tensile strength at 23 ° C. is measured in accordance with JIS K 6251, and 170% when the tensile elongation at break is measured in accordance with JIS K 6251 230% or more, 1400 N/mm ² or more and 2250 N/mm ² or less when the tensile modulus at 23 ° C. is measured in accordance with JIS K 6251, and the static friction coefficient at 23 ° C. is in accordance with JIS K 7125-1999. 0.04 or more and 0.35 or less when measured, and 0.04 or more and 0.30 or less when the dynamic friction coefficient is measured in accordance with JIS K 7125-1999, and the loss tangent at 20 ° C. is 0.020. It is characterized by being 0.45 or less .

In addition, when an elastomer layer having a thickness of 10 μm or more and 100 μm or less is sandwiched between a pair of diaphragm resin films, and the durometer hardness of this elastomer layer is measured with a durometer type A according to JIS K 6253. In addition, it can be A10 or more and A90 or less.

Moreover, the diamine component of the thermoplastic polyimide resin is preferably a linear aliphatic diamine having 4 to 12 carbon atoms.
Moreover, the diamine component of the crystalline thermoplastic polyimide resin preferably contains at least an alicyclic diamine.

Also, the alicyclic diamine is preferably 1,3-bis(aminomethyl)cyclohexane.

Further, in order to solve the above problems, the present invention provides a method for manufacturing a resin film for a diaphragm of a portable device speaker according to claim 1, 2, or 3, comprising :
A molding material is prepared from 100 parts by mass of a crystalline thermoplastic polyimide resin and 1 part by mass or more and 100 parts by mass or less of an adhesive fluororesin, and the thermoplastic polyimide resin of the molding material contains at least a tetracarboxylic component and an aliphatic Diamine is a diamine component as a main component, and the apparent shear viscosity of the adhesive fluororesin at 350° C. is 9×10 2 ^Pa ·s or more and 2×10 ⁴ Pa·s or less under a load of 50 kgf,
The molding material is melt-kneaded and put into an extruder, and the molding material is extruded into a resin film for a diaphragm of a speaker of a portable device using the die of the extruder, and the resin film for a diaphragm is brought into contact with a cooling roll. and then the cooled resin film for diaphragm is wound by a winder.

Here, the resin film for a diaphragm of a portable device speaker in the scope of claims includes a resin sheet as well as a resin film. The resin film for the diaphragm of the portable device speaker may be transparent, opaque, translucent, unstretched, uniaxially stretched, or biaxially stretched. Moreover, the resin film for the diaphragm of the portable device speaker may be one sheet, or may be plural sheets. In this case, for example, an elastomer layer is interposed between a pair of resin films for a diaphragm of a portable device speaker, and an adhesive primer is placed between the resin film for a diaphragm of a portable device speaker and the elastomer layer. Layers can be interposed.

According to the present invention, since the molding material is prepared from the crystalline thermoplastic polyimide resin and the adhesive fluororesin, the loss tangent is increased, and good sound quality characteristics with suppressed resonance can be obtained. In addition, since the molding material contains a crystalline thermoplastic polyimide resin, it is possible to obtain a resin film for a diaphragm of a portable device speaker that is excellent in toughness, high heat resistance, high solvent resistance, low-pitched sound characteristics, and the like. In addition, since it contains an adhesive fluororesin with excellent dispersibility, it is possible to obtain excellent lubricity, and wrinkles are less likely to occur when the resin film for the diaphragm of the portable device speaker is wound.

According to the present invention, even if molded from a crystalline thermoplastic polyimide resin, improvement in lubricity can be expected, and wrinkles can be prevented when winding a resin film for a diaphragm of a portable device speaker. Moreover, the increase in loss tangent suppresses the occurrence of resonance, thereby obtaining an effect of obtaining good sound quality. In addition, since the apparent shear viscosity of the adhesive fluororesin at 350°C is 9 × 10 ² Pa s or more and 2 × 10 ⁴ Pa s or less when the load is 50 kgf , the adhesiveness in the crystalline thermoplastic polyimide resin The fluororesin can be uniformly dispersed, and it is expected to produce a resin film for the diaphragm of the speaker of a mobile device, which is excellent in mechanical properties, slipperiness, and sound quality properties.
In addition, when the maximum tensile strength at 23 ° C. is measured in accordance with JIS K 6251, it is 52 N / mm 2 or more and ⁶⁸ N / mm ² or less, and when the tensile elongation at break is measured in accordance with JIS K 6251, Since it is 170% or more and 230% or less, it is possible to secure the rigidity of the resin film for the diaphragm of the portable device speaker and prevent it from being easily deformed during processing of the portable device speaker. I can expect it. In addition, when the tensile modulus of elasticity at 23° C. is measured according to JIS K 6251, it is 1400 N/mm ² or more and 2250 N/mm ² or less. It is possible to prevent easy deformation during processing of the speaker, and an improvement in bass characteristics can also be expected.
In addition, the static friction coefficient at 23 ° C. is 0.04 or more and 0.35 or less when measured in accordance with JIS K 7125-1999, and the dynamic friction coefficient is 0 when measured in accordance with JIS K 7125-1999. Since it is 0.04 or more and 0.30 or less, excellent lubricity can be expected. Furthermore, since the loss tangent at 20° C. is 0.020 or more and 0.45 or less, resonance can be prevented and good sound quality can be obtained.

According to the second aspect of the invention, the durometer hardness of the elastomer layer is A10 or more and A90 or less when measured with a durometer type A according to JIS K 6253. It is possible to suppress deterioration of the sound quality and deterioration of the sound quality caused by a decrease in the vibration propagation velocity of the diaphragm of the portable device speaker. Also, it is possible to prevent deterioration of the performance of the diaphragm due to a decrease in the loss tangent.

According to the third aspect of the invention, the diamine component of the thermoplastic polyimide resin contains at least a linear aliphatic diamine having 4 to 12 carbon atoms. Subsequent workability and low hygroscopicity can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall explanatory diagram schematically showing an embodiment of a resin film for a diaphragm of a portable device speaker according to the present invention and a method for producing the same. FIG. 5 is an explanatory view schematically showing a second embodiment of a resin film for a diaphragm of a portable device speaker according to the present invention;

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As shown in FIG. A thermoplastic polyimide resin is prepared from at least a tetracarboxylic component and a diamine component containing an aliphatic diamine as a main component, and is used for a micro speaker of a mobile phone. Used for diaphragms, etc.

The molding material 2 is prepared by containing 100 parts by mass of a crystalline thermoplastic polyimide (PI) resin and 1 to 100 parts by mass of an adhesive fluororesin. The molding material 2 contains a crystalline thermoplastic polyimide resin, an adhesive fluorine resin, an antioxidant, a light stabilizer, an ultraviolet absorber, a plasticizer, a lubricant, and a flame retardant, as long as the properties of the present invention are not impaired. , antistatic agents, heat resistance improvers, inorganic compounds, organic compounds, resin modifiers and the like are selectively added.

The crystalline thermoplastic polyimide resin of the molding material 2 is obtained by polymerization of a tetracarboxylic acid component and a diamine component. Tetracarboxylic acid components of the thermoplastic polyimide resin include cyclobutane-1,2,3,4-tetracarboxylic acid, cyclopentane-1,2,3,4-tetracarboxylic acid, cyclohexane-1,2,4,5 -alicyclic tetracarboxylic acids such as tetracarboxylic acids, 3,3',4,4'-diphenylsulfonetetracarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, biphenyltetracarboxylic acid, naphthalene -1,4,5,8-tetracarboxylic acid, pyromellitic acid and the like. Alkyl esters thereof can also be used.

Among these, pyromellitic acid preferably accounts for more than 50 mol % of the tetracarboxylic acid component. This is because if the tetracarboxylic acid component contains pyromellitic acid as the main component, the heat resistance, secondary workability, and low water absorbency of the resin film 1 for diaphragm of a portable device speaker are improved. From this point of view, pyromellitic acid in the tetracarboxylic acid component is preferably 60 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more. Most preferably, all (100 mol %) of the tetracarboxylic acid component is pyromellitic acid.

It is important that the diamine component constituting the crystalline thermoplastic polyimide resin is mainly composed of an aliphatic diamine (including an alicyclic diamine). That is, it is important that more than 50 mol % of the diamine component is aliphatic diamine, preferably 60 mol % or more, more preferably 80 mol % or more, and 90 mol % or more. It is particularly preferred to have Optimally, all (100 mol %) of the diamine component is an aliphatic diamine. By using the aliphatic diamine as the main component, the resin film 1 for a diaphragm of a portable device speaker can be provided with excellent heat resistance, low water absorption, moldability, and secondary workability.

The aliphatic diamine contained in the diamine component is not particularly limited as long as it is a diamine component having amine groups at both ends of a hydrocarbon group. It preferably contains an alicyclic diamine having amine groups at both ends. Specific examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4′-diaminodicyclohexylmethane, 4,4′-methylenebis(2- methylcyclohexylamine), isophoronediamine, norbornanediamine, bis(aminomethyl)tricyclodecane, and the like. Among these, 1,3-bis(aminomethyl)cyclohexane is most suitable from the viewpoint of achieving both heat resistance, moldability, and secondary workability.

When emphasizing the moldability and secondary workability of the resin film 1 for a diaphragm of a portable device speaker, a straight-chain hydrocarbon having amine groups at both ends of a straight-chain hydrocarbon is used as the aliphatic diamine contained in the diamine component. It preferably contains an aliphatic diamine. The linear aliphatic diamine is not particularly limited as long as it is a diamine component having an amine group at both ends of an alkyl group. 3), butanediamine (4 carbon atoms), pentanediamine (5 carbon atoms), hexanediamine (6 carbon atoms), heptanediamine (7 carbon atoms), octanediamine (8 carbon atoms), nonanediamine (9 carbon atoms) , decanediamine (10 carbons), undecanediamine (11 carbons), dodecanediamine (12 carbons), tridecanediamine (13 carbons), tetradecanediamine (14 carbons), pentadecanediamine (15 carbons), Hexadecanediamine (16 carbons), heptadecanediamine (17 carbons), octadecanediamine (18 carbons), nonadecanediamine (19 carbons), eicosane (20 carbons), triacontane (30 carbons), tetra Contane (40 carbon atoms), pentacontane (50 carbon atoms) and the like can be mentioned.

Among these, linear aliphatic diamines having 4 to 12 carbon atoms are most suitable from the viewpoint of excellent moldability, secondary workability, and low hygroscopicity. This linear aliphatic diamine may have a branched structure with 1 to 10 carbon atoms.

Other diamine components may be included as components other than the aliphatic diamine contained in the diamine component. Specifically, 1,4-phenylenediamine, 1,3-phenylenediamine, 2,4-toluenediamine, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, α,α'-bis(4-aminophenyl ) 1,4′-diisopropylbenzene, α,α′-bis(3-aminophenyl)-1,4-diisopropylbenzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 4,4 '-diaminodiphenylsulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,6-diaminonaphthalene, 1,5-diaminonaphthalene, p- aromatic diamine components such as xylylenediamine and m-xylylenediamine; ether diamine components such as polyethylene glycol bis(3-aminopropyl) ether and polypropylene glycol bis(3-aminopropyl) ether; and siloxane diamines. .

The diamine component may contain either or both of an alicyclic diamine and a linear aliphatic diamine. It is desirable to include both When both the alicyclic diamine and the linear aliphatic diamine are included, the content of each is alicyclic diamine: linear aliphatic diamine = 99: 1 to 1: 99 mol%. preferably 90:10 to 10:90 mol%, more preferably 80:20 to 20:80 mol%, particularly preferably 70:30 to 30:70 mol%, 60:40 to 40:60 mol % is optimal. If the ratio of the alicyclic diamine and the linear aliphatic diamine contained in the diamine component is in the range, the heat resistance and moldability of the resin film 1 for a diaphragm of a portable device speaker are well balanced.

The melting point (also called melting temperature) of the crystalline thermoplastic polyimide resin is 280° C. or higher and 370° C. or lower, preferably 300° C. or higher and 350° C. or lower, more preferably 310° C. or higher and 330° C. or lower. This is because if the melting point of the crystalline thermoplastic polyimide resin is less than 280° C., the heat-resistant resin film 1 for the diaphragm of the portable device speaker cannot be obtained. On the other hand, when the melting point of the crystalline thermoplastic polyimide resin exceeds 370° C., the manufacturing temperature of the resin film 1 for the diaphragm of the portable device speaker exceeds 400° C. This is because it is difficult to manufacture the resin film 1 for industrial use, and problems such as limitation of the melt extruder 10 that can be used arise.

The glass transition point of the crystalline thermoplastic polyimide resin is 160° C. or higher and 240° C. or lower, preferably 170° C. or higher and 210° C. or lower, more preferably 170° C. or higher and 190° C. or lower. This is because if the glass transition point of the crystalline thermoplastic polyimide resin is less than 160° C., the heat-resistant resin film 1 for the diaphragm of the portable device speaker cannot be obtained. On the other hand, when the glass transition point of the crystalline thermoplastic polyimide resin exceeds 240° C., the melting point of the crystalline thermoplastic polyimide resin exceeds 370° C. This is because the production temperature exceeds 400° C. or higher, which hinders the production of the diaphragm resin film 1 for portable device speakers and limits the melt extruder 10 that can be used.

The apparent shear viscosity of the crystalline thermoplastic polyimide resin is 1×10 ² Pa s or more and 1×10 ⁴ Pa s or less at an apparent shear rate of 1×10 ² sec ⁻¹ at a temperature of 350° C. Within the range, preferably from 5×10 ² Pa·s to 5×10 ³ Pa·s, more preferably from 7×10 ² Pa·s to 1×10 ³ Pa·s. This is because the apparent shear viscosity of the crystalline thermoplastic polyimide resin at a temperature of 350° C. and an apparent shear rate of 1×10 ² sec ⁻¹ is in the range of 1×10 ² Pa s or more and 1×10 ⁴ Pa s or less. This is because the dispersibility of the adhesive fluororesin in the crystalline thermoplastic polyimide resin is improved, and it becomes possible to prepare the molding material 2 having excellent resin film moldability. Moreover, it is based on the reason that the resin film 1 for diaphragms which has the mechanical characteristic and sound quality characteristic suitable for a portable device speaker can be obtained.

As the crystalline thermoplastic polyimide resin, random copolymers, alternating copolymers, block copolymers, or modified products with other copolymerizable monomers are used as long as the effects of the present invention are not impaired. be able to. Further, the shape of the crystalline thermoplastic polyimide resin may be any shape such as powder, flakes, pellets, lumps, and the like.

The crystalline thermoplastic polyimide resin is not particularly limited, but preferably has thermoplasticity as described in Japanese Patent No. 5365762, Japanese Patent No. 6024859, Japanese Patent No. 6037088, or Japanese Patent No. 6394662. A polyimide resin, more preferably a thermoplastic polyimide resin described in Japanese Patent No. 6024859, Japanese Patent No. 6037088 or Japanese Patent No. 6394662 is suitable. A specific example of this thermoplastic polyimide resin is the Surprime series [manufactured by Mitsubishi Gas Chemical Co., Ltd.: product name], which is excellent in high strength, high heat resistance, high solvent resistance, crystallinity and film formability.

A crystalline thermoplastic polyimide resin is used for the molding material 2. When an amorphous thermoplastic polyimide resin is used, the tensile modulus exceeds 3000 N/mm ² and the F ₀ value increases. This is based on the reason that the low-frequency characteristics deteriorate. A specific example of the amorphous thermoplastic polyimide resin is a polyetherimide resin. As the polyetherimide resin, a polycondensate of 4,4′-[isopropylidenebis(p-phenyleneoxy)diphthalic dianhydride and m-phenylenediamine [manufactured by SABIC Innovative Plastics, product name: ULTEM 1010 ], or a condensation polymer of 4,4′-[isopropylidenebis(p-phenyleneoxy)diphthalic dianhydride and p-phenylenediamine [manufactured by SABIC Innovative Plastics, product name: ULTEM CRS5001].

The adhesive fluororesin has a repeating unit (a) based on tetrafluoroethylene (hereinafter referred to as TFE) and/or chlorotrifluoroethylene (hereinafter referred to as CTFE), a dicarboxylic anhydride group, and in the ring Repeating unit (b) based on a cyclic hydrocarbon monomer having a polymerizable unsaturated group, and repeating based on other monomers (excluding repeating units (a) and (b) if they overlap) Contains unit (c).

In the adhesive fluororesin, the repeating unit (a) is 50 to 99.89 mol% with respect to the total molar amount of the repeating unit (a), the repeating unit (b), and the repeating unit (c), the repeating unit (b ) is 0.01 to 5 mol %, and the repeating unit (c) is 0.1 to 49.99 mol %. Preferably, the repeating unit (a) is 50 to 99.47 mol%, the repeating unit (b) is 0.03 to 3 mol%, and the repeating unit (c) is 0.5 to 49.97 mol%, more preferably contains 50 to 98.95 mol % of repeating unit (a), 0.05 to 2 mol % of repeating unit (b), and 1 to 49.95 mol % of repeating unit (c).

This is because when the mol % of the repeating unit (a), the repeating unit (b), and the repeating unit (c) are within the range, the heat resistance and chemical resistance of the adhesive fluororesin are improved. Further, when the mol% of the repeating unit (b) is within the range, the adhesive fluororesin has excellent adhesiveness to the crystalline thermoplastic polyimide resin. Furthermore, if the mol % of the repeating unit (c) is within the range, the adhesive fluororesin will be excellent in mechanical properties such as moldability and stress crack resistance.

The "cyclic hydrocarbon monomer having a dicarboxylic anhydride group and a polymerizable unsaturated group in the ring" (hereinafter simply referred to as a cyclic hydrocarbon monomer) has one or more five-membered rings or six A polymerizable compound which is a cyclic hydrocarbon consisting of a membered ring and has a dicarboxylic anhydride group and an intracyclic polymerizable unsaturated group.

As cyclic hydrocarbons, cyclic hydrocarbons having one or more bridged polycyclic hydrocarbons are preferred. That is, a cyclic hydrocarbon consisting of a bridged polycyclic hydrocarbon, a cyclic hydrocarbon in which two or more bridged polycyclic hydrocarbons are condensed, or a cyclic hydrocarbon in which a bridged polycyclic hydrocarbon and another cyclic hydrocarbon are condensed Preferably. In addition, this cyclic hydrocarbon monomer has one or more intracyclic polymerizable unsaturated groups, ie, one or more polymerizable unsaturated groups present between carbon atoms constituting a hydrocarbon ring. The cyclic hydrocarbon monomer further has a dicarboxylic anhydride group (--CO--O--CO--), and the dicarboxylic anhydride group may be bonded to two carbon atoms constituting the hydrocarbon ring, and the ring It may be bonded to two outer carbon atoms.

Preferably, the dicarboxylic anhydride group is a carbon atom that constitutes the ring of the cyclic hydrocarbon and bonds to two adjacent carbon atoms. Furthermore, instead of hydrogen atoms, halogen atoms, alkyl groups, halogenated alkyl groups, and other substituents may be bonded to the carbon atoms that constitute the ring of the cyclic hydrocarbon. Specific examples include those represented by the following formulas (1) to (8). Here, R in the formulas (2), (5) to (8) is a lower alkyl group having 1 to 6 carbon atoms, a halogen atom selected from a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, the lower A halogenated alkyl group in which a hydrogen atom in the alkyl group is substituted with a halogen atom.

As the cyclic hydrocarbon monomer, preferably represented by formula (1), 5-norbornene-2,3-dicarboxylic anhydride (hereinafter referred to as NAH), represented by formulas (3) and (4) Cyclic hydrocarbon monomers that are acid anhydrides, formulas (2), and formulas (5) to (8) include cyclic hydrocarbon monomers in which the substituent R is a methyl group. NAH is more preferable.

Other monomers include vinyl fluoride, vinylidene fluoride (hereinafter referred to as VdF), CTFE (except when used as repeating unit (a)), trifluoroethylene, hexafluoropropylene (hereinafter referred to as HFP ), CF ₂ ═CFOR ^{f 1} (wherein R ^{f 1} is a perfluoroalkyl group having 1 to 10 carbon atoms and which may contain an oxygen atom between carbon atoms), CF ₂ ═CFOR ^{f 2} SO ₂ X ¹ (R ^{f 2} is a perfluoroalkylene group having 1 to 10 carbon atoms which may contain an oxygen atom between carbon atoms, X ¹ is a halogen atom or a hydroxyl group), CF ₂ ═CFOR ^{f 2} CO ₂ X ² (wherein R ^{f 2} is the above X ² is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms), CF ₂ =CF(CF ₂ ) _p OCF=CF ₂ (where p is 1 or 2), CH ₂ =CX ³ (CF ₂ ) _q X ⁴ (where X ³ and X ⁴ are each independently a hydrogen atom or a fluorine atom, q is an integer of 2 to 10), perfluoro(2-methylene-4-methyl-1,3-dioxolane ), olefins having 2 to 4 carbon atoms such as ethylene, propylene and isobutene, vinyl esters such as vinyl acetate, and vinyl ethers such as ethyl vinyl ether and cyclohexyl vinyl ether. Other monomers may be used singly or in combination of two or more.

Specific examples of _CF2 = _CFOR ^f1 include _{CF2 = CFOCF2CF3 , CF2} = _{CFOCF2CF2CF3 , CF2} = _{CFOCF2CF2CF2CF3 , CF2 =} CFO( _CF2 ) ₈ F and the like. _{Preferably , CF2} = _CFOCF2CF2CF3 . Further, as specific examples of _CH2 = ^CX3 ( _CF2 ) _qX4 ^, for example, _CH2 =CH( _CF2 ) _2F , _CH2 =CH( _CF2 ) _3F , _CH2 =CH( _CF2 ) ₄ F, CH ₂ =CF(CF ₂ ) ₃ H, CH ₂ =CF(CF ₂ ) ₄ H and the like. Preferably _CH2 =CH( _CF2 ) _4F or _CH2 =CH( _CF2 ) _2F .

Other monomers preferably include VdF, HFP, CTFE (except when used as repeating unit (a)), CF ₂ =CFOR ^{f 1} , CH ₂ =CX ³ (CF ₂ ) _q X ⁴ , One or more selected from the group consisting of ethylene, propylene and vinyl acetate, more preferably HFP, CTFE (except when used as repeating unit (a)), CF ₂ =CFOR ^{f 1} , ethylene and _CH2 = ^CX3 ( _CF2 ⁾ _qX4 . Most preferably HFP or CF ₂ =CFOR ^{f 1} . As CF ₂ =CFOR ^{f 1} , R ^{f 1} is preferably a perfluoroalkyl group having 1 to 6 carbon atoms, more preferably a perfluoroalkyl group having 2 to 4 carbon atoms, and most preferably a perfluoropropyl group.

Specific examples _of the adhesive fluororesin include TFE/ _CF2 = _CFOCF2CF2CF3 /NAH copolymer, TFE _{/ HFP} /NAH copolymer, TFE/ _CF2 = _{CFOCF2CF2CF3 /} HFP/NAH copolymer, TFE/VdF/NAH copolymer, TFE/ _CH2 =CH( _CF2 ) _4F /NAH/ethylene copolymer, TFE/ _CH2 =CH( _CF2 ) _2F /NAH /ethylene copolymer, CTFE/ _CH2 =CH( _CF2 ) _4F /NAH/ethylene copolymer, CTFE/ _CH2 =CH( _CF2 ) _2F /NAH/ethylene copolymer, CTFE/ _CH2 ═CH(CF ₂ ) ₂ F/NAH/ethylene copolymer and the like.

The melting point of the adhesive fluororesin is preferably 150° C. or higher and 320° C. or lower, more preferably 200° C. or higher and 310° C. or lower. This melting point can be prepared by appropriately selecting the content ratio of the repeating unit (a), the repeating unit (b), and the repeating unit (c) within the above range.

As the polymer terminal group of the adhesive fluororesin, if it has an adhesive functional group such as an ester group, a carbonate group, a hydroxyl group, a carboxyl group, a carbonyl fluoride group, or an acid anhydride residue, crystals other than the adhesive fluororesin It is preferable because it is excellent in adhesiveness with a thermoplastic polyimide resin having a high viscosity. Moreover, the polymer terminal group having an adhesive functional group can be introduced by appropriately selecting a radical polymerization initiator, a chain transfer agent, etc. during the production of the adhesive fluororesin.

The apparent shear viscosity of the adhesive fluororesin at a temperature of 350° C. is 1×10 ² Pa.s or more and 1×10 ⁵ Pa.s or less, preferably 7×10 ² Pa.s or more when a load of 50 kgf is applied. 5×10 ⁴ Pa·s or less, more preferably 9×10 ² Pa·s or more and 2×10 ⁴ Pa·s or less. This is because the adhesive fluororesin can be uniformly dispersed in the crystalline thermoplastic polyimide resin if the apparent shear viscosity is within this range, and the portable device has excellent mechanical properties, slipperiness, and sound quality properties. This is because the production of the resin film 1 for speaker diaphragms can be expected.

A method for producing the adhesive fluororesin is not particularly limited, but a radical polymerization method using a radical polymerization initiator is used. Examples of this polymerization method include bulk polymerization, solution polymerization using organic solvents such as fluorocarbons, chlorinated hydrocarbons, fluorochlorohydrocarbons, alcohols and hydrocarbons, aqueous media and, if necessary, suitable organic solvents. Suspension polymerization to be used, emulsion polymerization to use an aqueous medium and an emulsifier may be mentioned, but solution polymerization is particularly desirable.

The adhesive fluororesin is not particularly limited, but is preferably the adhesive fluororesin described in Japanese Patent No. 4424246, Japanese Patent No. 5263269, Japanese Patent No. 5365939, or Japanese Patent Application Laid-Open No. 2019-43134. can give. Specific examples of this adhesive fluororesin include LH-8000 [manufactured by AGC: product name], AH-5000 [manufactured by AGC: product name], AH-2000 [manufactured by AGC: product name] EA-2000, etc. [manufactured by AGC: product name]. Among these adhesive fluororesins, EA-2000, which is excellent in heat resistance, is suitable.

The amount of the adhesive fluororesin to be added is 1 part by mass or more and 100 parts by mass or less, preferably 5 parts by mass or less and 90 parts by mass or less, more preferably 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the crystalline thermoplastic polyimide resin. It is below the department. This is because if the amount added is less than 1 part by mass, improvement in the loss tangent of the resin film 1 for a diaphragm of a portable device speaker cannot be expected. This is because the resin film 1 for the diaphragm of the device speaker is inferior in rigidity, so that the handleability during processing of the speaker of the portable device is deteriorated. From the above, if the amount of the adhesive fluororesin added is within the range of 1 part by mass or more and 100 parts by mass or less, the vibration of the mobile device speaker is excellent in sound quality characteristics that suppresses the occurrence of resonance, and further prevents deterioration in handling performance. A board resin film 1 is obtained.

In the molding material 2, in addition to the above resins, polyimide resins such as polyimide (PI) resins, polyamideimide (PAI) resins, polyetherimide (PEI) resins, polyamide 4T (PA4T) resins, polyamide 6T (PA6T) resins, etc. ) resin, modified polyamide 6T (PA6T) resin, polyamide 9T (PA9T) resin, polyamide 10T (PA10T) resin, polyamide 11T (PA11T) resin, polyamide 6 (PA6) resin, polyamide 66 (PA66) resin, polyamide 46 (PA46 ) resins such as polyamide resins, polyethylene terephthalate (PET) resins, polybutylene terephthalate (PBT) resins, polyester resins such as polyethylene naphthalate (PEN) resins, polyether ketone (PEK) resins, polyether ether ketone (PEEK) resins , polyether ether ether ketone (PEEEK) resin, polyether ketone ketone (PEKK) resin, polyether ether ketone ketone (PEEKK) resin, polyarylene ether ketone resin such as polyether ketone ether ketone ketone (PEKEKK) resin, polysulfone ( PSU) resin, polyether sulfone (PES) resin, polysulfone resin such as polyphenylsulfone (PPSU) resin, polyphenylene sulfide (PPS) resin, polyphenylene sulfide ketone resin, polyphenylene sulfide sulfone resin, polyphenylene sulfide ketone sulfone resin, etc. Polyarylene sulfide resin, liquid crystal polymer (LCP), polycarbonate (PC) resin, polyarylate (PAR) resin and the like are added as necessary.

In the above, when manufacturing the resin film 1 for the diaphragm of the portable device speaker, first, as shown in FIG. 1, the crystalline thermoplastic polyimide resin and the adhesive fluororesin are stirred and mixed at room temperature. After melt-kneading for a predetermined time to prepare a molding material 2, the molding material 2 is continuously molded into a band-shaped resin film 1 for a diaphragm of a portable device speaker.

The method for preparing the molding material 2 is as follows: (1) A crystalline thermoplastic polyimide resin and an adhesive fluororesin are stirred and mixed at room temperature, and then melted and kneaded to obtain a molding material for the resin film 1 for the diaphragm of a portable device speaker. (2) adding an adhesive fluororesin to a molten crystalline thermoplastic polyimide resin without stirring and mixing the crystalline thermoplastic polyimide resin and the adhesive fluororesin; A method of preparing the molding material 2 by melt-kneading may be mentioned. In addition, in this invention, "room temperature" means 0 degreeC or more and 50 degrees C or less.

Any of these methods can be adopted, but method (1) is preferable from the viewpoint of dispersibility and workability. First, the method (1) will be explained. When stirring and mixing the crystalline thermoplastic polyimide resin and the adhesive fluororesin, a tumbler mixer, a Hensil mixer, a V-type mixer, a Nauta mixer, and a ribbon blender are used. Alternatively, a universal stirring mixer or the like is used.

The crystalline thermoplastic polyimide resin and the adhesive fluororesin are mixed by mixing rolls, pressure kneaders, Banbury mixers, planetary mixers, twin-screw extruders, tri-screw extruders, and four-screw extruders. The molding material 2 is prepared by being melt-kneaded and dispersed by a multi-screw extruder such as a molding machine. When the molding material 2 is prepared, the temperature of the melt-kneader should be 300° C. or higher and 400° C. or lower, preferably 330° C. or higher and 370° C. or lower. This is because if the temperature of the melt extruder 10 exceeds 400° C., the adhesive fluororesin is violently decomposed, which is undesirable.

Next, the method (2) will be described. In this method, a crystalline thermoplastic polyimide resin is mixed with a mixing roll, a pressure kneader, a Banbury mixer, a planetary mixer, a twin-screw extruder, and a tri-screw extruder. The thermoplastic polyimide resin and the adhesive fluororesin are melted in a molding machine, a multi-screw extruder such as a four-screw extruder, etc., and the adhesive fluororesin is added to the thermoplastic polyimide resin and melt-kneaded to disperse it. is prepared. When preparing a composition comprising a thermoplastic polyimide resin and an adhesive fluororesin, the temperature of the melt kneader should be 300° C. or higher and 400° C. or lower, preferably 330° C. or higher and 370° C. or lower. This is because when the temperature of the melt extruder 10 exceeds 400° C., the adhesive fluororesin is violently decomposed as described above.

The molding material 2 is usually extruded into lumps, strands, sheets, or rods, and then processed into powder, granules, pellets, or other forms suitable for molding using a crusher or a cutter.

The resin film 1 for the diaphragm of the portable device speaker made of the molding material 2 can be produced by a known method such as a melt extrusion molding method, a power render molding method, or a casting molding method. Here, the melt extrusion molding method is a molding material 2 of a crystalline thermoplastic polyimide resin and an adhesive fluororesin using a melt extrusion molding machine 10 consisting of a single-screw extruder, a twin-screw extruder, or the like. are melted and kneaded, and the belt-shaped resin film 1 for the speaker diaphragm of a mobile device is continuously extruded from a T-die 13 at the tip of a melt extruder 10. From the standpoint of ease of handling and simplification of equipment, melt extrusion molding is the most suitable method for manufacturing the resin film 1 for a diaphragm of a portable device speaker.

The melt extruder 10 is, for example, a single-screw extruder, a twin-screw extruder, or the like, and functions to melt and knead the molding material 2 that is fed. A raw material inlet 11 for the molding material 2 is installed in the upper rear portion of the melt extruder 10, and the raw material inlet 11 contains helium gas, neon gas, argon gas, krypton gas, nitrogen gas, and carbon dioxide gas. An inert gas supply pipe 12 is connected to supply an inert gas such as a is prevented.

As the melt extruder 10 such as a single-screw extruder or a twin-screw extruder, it is preferable to use a melt extruder 10 having a vent port. This is because the use of the vent port for melt-kneading under reduced pressure makes it easier to sufficiently deaerate moisture and sublimated organic matter contained in the molding material 2 . Also, it is not necessary to adjust the moisture content of the molding material 2 before melt-kneading.

The temperature during melt kneading in the melt extruder 10 is not particularly limited as long as it is a temperature at which the molding material 2 can be melted and the temperature at which the molding material 2 does not decompose. A range below the decomposition temperature is good. Specifically, the temperature is adjusted to 300° C. or higher and 400° C. or lower, preferably 330° C. or higher and 370° C. or lower. This is because if the temperature is less than 300°C, the molding material 2 containing the thermoplastic polyimide resin cannot be melt-extruded, and if the temperature exceeds 400°C, the adhesive fluororesin may be violently decomposed. because there is

The molding material 2 melted and kneaded by the melt extruder 10 is continuously extruded into the band-shaped resin film 1 for the diaphragm of the portable device speaker by means of a T-die 13 at the tip of the melt extruder 10. A continuous resin film 1 for a diaphragm of a portable device speaker is sandwiched between a pair of lower pressing rolls 17 and a cooling roll 18 to be cooled, and then wound by a winder 20 to manufacture the film.

The T-die 13 is attached to the tip of the melt extruder 10 through a connecting pipe 14, and functions to continuously push downward the band-shaped resin film 1 for the diaphragm of the portable device speaker. The temperature of the T-die 13 during extrusion is in the range of the melting point of the molding material 2 or more and less than the thermal decomposition temperature. Specifically, the temperature is adjusted to 300° C. or higher and 400° C. or lower, preferably 330° C. or higher and 370° C. or lower. When the temperature is less than 300°C, the molding material 2 containing the crystalline thermoplastic polyimide resin cannot be melt-extruded, and when the temperature exceeds 400°C, the adhesive fluororesin is severely decomposed. because there is a risk of

A gear pump 15 and a filter 16 are preferably attached to the connecting pipe 14 upstream of the T-die 13 . The gear pump 15 transfers the molding material 2 melted and kneaded by the melt extruder 10 to the T-die 13 at a constant flow rate and with high accuracy through the filter 16 . The filter 16 separates gel, foreign matter, etc. from the molten molding material 2 and transfers the molten molding material 2 to the T-die 13 .

A pair of pressing rolls 17 are rotatably supported below the T-die 13 and sandwich a cooling roll 18 so as to be slidably contactable. The film 1 is clamped and cooled. A winding tube 21 of a winder 20 for winding the resin film 1 for a diaphragm of a portable device speaker is rotatably installed further downstream of the downstream pressure roll 17 among the pair of pressure rolls 17, and pressure is applied. Between the roll 17 and the winding tube 21 of the winding machine 20, a slit blade 22 for forming a slit in the side portion of the resin film 1 for a diaphragm of a portable device speaker is arranged so as to be able to move up and down. Between the blade 22 and the winding tube 21 of the winding machine 20, there is a rotatable tension roll 19 for applying tension to the resin film 1 for the diaphragm of the portable device speaker and smoothly winding it. Supported.

At least natural rubber, isoprene rubber, butadiene rubber, silicone rubber, fluororubber, or the like is applied on the peripheral surface of each compression roll 17 from the viewpoint of improving the adhesion between the diaphragm resin film 1 of the portable device speaker and the cooling roll 18 . If necessary, a rubber layer is formed, and an inorganic compound such as silica or alumina is selectively added to the rubber layer. Among these, it is preferable to adopt silicone rubber and fluororubber, which are excellent in heat resistance.

As the pressing roll 17, a metal elastic roll having a metal surface is used as necessary. When this metal elastic roll is used, the surface of the resin film 1 for the diaphragm of the portable device speaker having excellent smoothness is obtained. Molding becomes possible. Specific examples of metal elastic rolls include metal sleeve rolls, air rolls [manufactured by Dymco Corporation: product name], and UF rolls [manufactured by Hitachi Zosen Corporation: product name].

Such pressure roller 17 is adjusted to a temperature of 50° C. or higher and 260° C. or lower, preferably 100° C. or higher and 240° C. or lower, more preferably 130° C. or higher and 220° C. or higher, further preferably 150° C. or higher and 200° C. or lower. The diaphragm resin film 1 of the device speaker is slidably contacted and pressed against the cooling roll 18 . The temperature range of the pressure roll 17 is that when the temperature of the pressure roll 17 exceeds 260° C., the resin film 1 for the diaphragm of the speaker of the mobile device being manufactured sticks to the pressure roll 17, causing the speaker of the mobile device to vibrate. This is because the board resin film 1 may be broken, or the rubber layer formed on the pressing roll 17 may be thermally decomposed.

Conversely, if the temperature of the pressure roll 17 is less than 50° C., condensation will occur on the pressure roll 17, which is not preferable. As a method for temperature adjustment and cooling of the pressing roll 17, a method using a heat medium such as air, water, oil, or the like, an electric heater, a dielectric heating roll, or the like can be used.

The cooling roll 18 is made of, for example, a metal roll having a diameter larger than that of the pressing roll 17 . The thickness is controlled within a predetermined range while cooling the resin film 1 for the diaphragm of the portable device speaker together with the compression roll 17 . The cooling roll 18 is heated to a temperature of 50° C. or higher and 260° C. or lower, preferably 100° C. or higher and 240° C. or lower, more preferably 130° C. or higher and 220° C. or higher, and still more preferably 150° C. or higher and 200° C. or lower. It is adjusted and comes into sliding contact with the diaphragm resin film 1 of the portable device speaker.

The reason why the temperature of the cooling roll 18 is adjusted to 50° C. or more and 260° C. or less is that when the temperature of the cooling roll 18 exceeds 260° C., the resin film 1 for the diaphragm of the speaker of the portable device being manufactured does not reach the cooling roll 18 . This is because there is a risk that the resin film 1 for the diaphragm of the speaker of a portable device may be broken due to adhesion to the pressure roller 17 or, in the case of the pressure roll 17 coated with a rubber layer, the rubber layer of the pressure roll 17 may be thermally decomposed. . On the other hand, if the temperature of the cooling roll 18 is less than 50° C., condensation will occur on the cooling roll 18, which is not preferable. The temperature adjustment and cooling method of the cooling roll 18 may be a method using a heat medium such as air, water, or oil, an electric heater, induction heating, or the like.

In the above, when more specifically and actually manufacturing the resin film 1 for the diaphragm of the portable device speaker, as shown in FIG. is supplied while supplying an inert gas indicated by an arrow in FIG. A resin film 1 for a diaphragm of a device speaker is continuously extruded in a belt shape.

At this time, the water content of the molding material 2 before melt extrusion is adjusted to 2000 ppm or less, preferably 1000 ppm or less, more preferably 100 ppm or more and 500 ppm or less. This is because if the moisture content exceeds 2000 ppm, the molding material 2 may foam immediately after being extruded from the T-die 13 .

After extruding the resin film 1 for the diaphragm of the portable device speaker, it is sequentially wound around a pair of pressure bonding rolls 17, the cooling roll 18, the tension roll 19, and the winding tube 21 of the winder 20, and the film for the diaphragm of the portable device speaker is wound. After the resin film 1 is cooled by the cooling roll 18, both sides of the resin film 1 for the diaphragm of the portable device speaker are cut by the slit blades 22, respectively, and the film is sequentially wound on the winding tube 21 of the winding machine 20. It is possible to manufacture the resin film 1 for the diaphragm of the portable device speaker. When manufacturing the resin film 1 for the diaphragm of the portable device speaker, fine irregularities are formed on the surface of the diaphragm resin film 1 for the portable device speaker to the extent that the effect of the present invention is not lost. The coefficient of friction of the surface of the diaphragm resin film 1 can be reduced.

The thickness of the resin film 1 for a diaphragm of a portable device speaker is not particularly limited as long as it is 1 μm or more and 1000 μm or less. 3 μm or more and 100 μm or less, more preferably 4 μm or more and 97 μm or less, further preferably 6 μm or more and 75 μm or less.

The relative crystallinity of the resin film 1 for a diaphragm of a portable device speaker is 80% or more, preferably 90% or more, more preferably 95% or more, and still more preferably 100%. This is because if the relative crystallinity of the resin film 1 for the diaphragm of the portable device speaker is less than 80%, the resin film 1 for the diaphragm of the portable device speaker has a problem in heat resistance. Also, if the relative crystallinity is 80% or more, it can be expected to ensure the mechanical strength and heat resistance that can be used for speakers of mobile devices.

The degree of crystallinity of the resin film 1 for a diaphragm of a portable device speaker can be represented by relative degree of crystallinity. The relative crystallinity of the diaphragm resin film 1 for portable device speaker is calculated by the following formula based on the results of thermal analysis measured at a temperature elevation rate of 10° C./min using a differential scanning calorimeter.
Relative crystallinity (%) = {1-(ΔHc/ΔHm)}×100
ΔHc: amount of heat at recrystallization peak (J/g)
ΔHm: heat quantity at melting peak (J/g)

The mechanical properties of the resin film 1 for a diaphragm of a portable device speaker can be evaluated by the maximum tensile strength at 23° C., the tensile elongation at break, and the tensile elastic modulus. The maximum tensile strength is 40 N/mm ² or more, preferably 50 N/mm ² or more and 200 N/mm ² or less, more preferably 52 N/mm ² or more and 68 N/mm ^{2 or} less, as measured according to JIS K 6781 or 7127. . Further, the tensile elongation at break is preferably 100% or more, preferably 150% or more and 300% or less, more preferably 170% or more and 230% or less, as measured by a method based on JIS K 6781 or 7127.

This is because when the maximum tensile strength is less than 40 N/mm ² and the elongation at break is less than 100%, the resin film 1 for the diaphragm of the portable device speaker does not have sufficient toughness. This is because there is a risk that troubles such as breakage or cracking may occur during processing of the resin film 1 for use, making production difficult.
The tensile elastic modulus of the resin film 1 for a diaphragm of a portable device speaker at 23° C. is 1000 N/mm ² or more and 3000 N/mm ^{2 or} less, preferably 1250 N/mm ² or more by a measurement method based on JIS K 6781 or JIS K 7127. The optimal range is 2750 N/mm ² or less, more preferably 1400 N/mm ² or more and 2250 N/mm ² or less.

This is because if the tensile modulus of elasticity is less than 1000 N/mm ² , the resin film 1 for the diaphragm of the portable device speaker is inferior in rigidity, and is easily deformed during processing of the portable device speaker. based on the reason that In addition, it is based on the reason that the improvement of the low-pitched sound characteristic cannot be aimed at. Conversely, if it exceeds 3000 N/mm ² , the F ₀ value increases and the bass characteristics cannot be improved.

The static friction coefficient of the resin film 1 for a diaphragm of a portable device speaker at 23° C. is 0.50 or less, preferably 0, from the viewpoint of obtaining excellent slipperiness when measured by a measurement method based on JIS K 7125-1999. 0.40 or less, more preferably 0.35 or less. Although the lower limit of the coefficient of static friction is not particularly limited, it is practically 0.04 or more. In addition, the dynamic friction coefficient of the resin film 1 for a diaphragm of a portable device speaker at 23° C. is 0.50 or less, preferably 0.50 or less, from the viewpoint of obtaining excellent slipperiness when measured by a measurement method based on JIS K 7125-1999. 0.40 or less, more preferably 0.30 or less. Although the lower limit of the coefficient of dynamic friction is not particularly limited, it is practically 0.04 or more.

In order to prevent resonance and obtain good sound quality, the loss tangent of the resin film 1 for a diaphragm of a portable device speaker at 20° C. is 0.014 or more, preferably 0.018 or more, more preferably 0.020 or more, and more preferably 0.020 or more. Optimum is 0.020 or more. This is because when the loss tangent is less than 0.015, resonance occurs and good sound quality cannot be obtained. Although the upper limit of the loss tangent is not particularly restricted, it is preferably 0.45 or less.

Fine unevenness can be formed on the front and back surfaces of the resin film 1 for a diaphragm of a portable device speaker to reduce the coefficient of friction. (2) A method of sandwiching the resin film 1 for a diaphragm of a portable device speaker between a pressing roll 17 provided and a cooling roll 18 having fine irregularities to form fine irregularities, (2) Resin film for a diaphragm of a portable device speaker A method of spraying fine inorganic compounds such as zirconia, glass, stainless steel, etc., polycarbonate resins, polyamide resins, or organic compounds such as plant seeds on 1 to form fine unevenness, (3) Resin for diaphragms of mobile device speakers. A method of press-molding the film 1 with a mold having fine unevenness to form fine unevenness can be mentioned. Among these methods, the method (1) is the most suitable from the viewpoints of simplification of equipment, accuracy of unevenness size, uniformity of unevenness formation, ease of unevenness formation, and continuous formation of unevenness. .

The method (1) will be described in more detail. While discharging onto a cooling roll 18 provided on the peripheral surface, this discharged material is sandwiched between the cooling roll 18 and a pressing roll 17 provided with fine unevenness on the peripheral surface, and the resin film 1 for the diaphragm of the portable device speaker is melt extruded. (1-2) A molded resin film 1 for a diaphragm of a portable device speaker is sandwiched between a pressing roll 17 having fine unevenness on its peripheral surface and a cooling roll 18 having fine unevenness on its peripheral surface. , and a method of forming unevenness. Among these, the method (1-1) is preferable from the viewpoint of simplification of equipment.

According to the above configuration, since the molding material 2 contains the crystalline thermoplastic polyimide resin, it is possible to obtain the resin film 1 for the diaphragm of the portable device speaker, which is excellent in high strength, high heat resistance, high solvent resistance, and the like. can. Further, an adhesive fluororesin having excellent dispersibility is added to the molding material 2 to reduce the static friction coefficient of the resin film 1 for the diaphragm of the portable device speaker to 0.260 or more and 0.350 or less, and to reduce the dynamic friction coefficient. Since it is as small as 0.160 or more and 0.290 or less, it is possible to obtain sufficient slipperiness, and when the resin film 1 for a diaphragm of a portable device speaker is wound by a winder 20, wrinkles are not generated. do not have. Therefore, it is possible to effectively solve the problem that the resin film 1 for the diaphragm of the portable device speaker is broken or damaged during manufacturing or secondary processing.

In addition, instead of fluororesins such as tetrafluoroethylene and perfluoroalkoxyethylene copolymers, adhesive fluororesins that are highly compatible with crystalline thermoplastic polyimide resins are used, making them suitable for use as diaphragm resins for mobile device speakers. The film 1 can be smoothly produced by a melt extrusion method. In addition, since the molding material 2 is prepared from a crystalline thermoplastic polyimide resin and an adhesive fluororesin, the loss tangent increases in addition to the bass characteristics, and excellent sound quality characteristics with suppressed resonance can be obtained. can. Therefore, important bass sounds can be emphasized and reproduced by the portable device without relying on the software of the portable device or without connecting a dedicated external speaker to the portable device.

In addition, since the bass characteristics can be improved without increasing the size and weight of the speaker, it is possible to contribute to the demand for thinner, smaller, and lighter portable equipment. In addition, since the resin film 1 for a diaphragm of a portable device speaker having a relative crystallinity of 80% or more, which is excellent in heat resistance, is used for the speaker, excellent heat resistance can be expected. Furthermore, since the diaphragm resin film 1 containing a crystalline thermoplastic polyimide resin with excellent heat radiation properties is used, the loss is reduced and the stable long-term use of the diaphragm resin film 1 for portable device speakers is possible.

Next, FIG. 2 shows a second embodiment of the present invention. It has a multi-layer structure in which an elastomer layer 3 having a thickness of 10 μm or more and 100 μm or less is sandwiched and adhered between resin films 1 .

Examples of elastomers for the elastomer layer 3 include silicone resins, urethane resins, acrylic resins, fluorine resins, polyester resins, polyamide resins, hydrocarbon resins, styrene resins, vinyl chloride resins, and vinyl acetate resins. Among these elastomers, silicone resins, particularly heat-curable silicone resins, are preferable because they are excellent in heat resistance, weather resistance, flame retardancy, sound quality characteristics, compression characteristics, and the like. Examples of heat-curable silicone resins include addition-curable millable silicone resins and addition-curable liquid silicone resins.

Addition-curing millable silicone resins are usually composed of organopolysiloxane, a silica-based filler, and a curing agent (a known curing agent obtained by combining a platinum-based catalyst and an organohydrogenpolysiloxane, and an organic peroxide, etc.). ) and various additives such as silica fine powder are used in the form of a composition.

In contrast, the addition-curable liquid silicone resin contains an organopolysiloxane containing at least two silicon-bonded alkenyl groups per molecule and at least two silicon-bonded hydrogen atoms per molecule. and an inorganic filler having an average particle diameter of 1 μm or more and 30 μm or less and a bulk density of 0.1 g/cm ³ or more and 0.5 g/cm ³ or less (diatomaceous earth, perlite, pulverized perlite foam) , mica, calcium carbonate, glass flakes, hollow fillers, etc.) and addition reaction catalysts (platinum black, platinic chloride, chloroplatinic acid, reactants of chloroplatinic acid and monohydric alcohols, chloroplatinic acid and olefins complex with, platinum bisacetoacetate, palladium-based catalyst, rhodium-based catalyst, etc.) is added in the form of a resin composition.

The durometer hardness of the silicone resin when the silicone resin is used for the elastomer layer 3 is A10 or more and A90 or less, preferably A20 or more and A70 or less, more preferably A20 or more and A70 or less, when measured with a durometer type A according to JIS K 6253. A range of A20 or more and A50 or less is optimal. This is because if the durometer hardness is less than A10, the compression set property of the silicone resin layer is deteriorated, or the vibration propagation speed of the diaphragm is lowered, resulting in a problem of sound quality. Conversely, if the durometer hardness exceeds A90, the loss tangent becomes small, resulting in deterioration of the performance of the diaphragm.

A multilayer structure may be formed in which a primer layer is interposed between the diaphragm resin film 1 and the elastomer layer 3 of a pair of portable device speakers for the purpose of firmly adhering them. Each primer is interposed between the elastomer layer 3 and the resin film 1 for the diaphragm of the portable device speaker, and functions to firmly bond them.

The primer is not particularly limited as long as it can adhere the silicone resin and the resin film 1 for the diaphragm of the portable device speaker. Modified products, oil-free alkyd resins, acrylic resins, silicone resins, epoxy resins, fluorine resins, phenolic resins, silane coupling agents, titanate coupling agents, aluminum coupling agents, and mixtures thereof. Examples of cross-linking agents for curing and/or cross-linking these resins include isocyanate compounds, melamine compounds, epoxy compounds, peroxides, phenol compounds, hydrogensiloxane compounds and silane compounds.

Each thin primer has a thickness of 0.1 μm to 5 μm, preferably 1 μm to 3 μm. This is because when the thickness of the primer is less than 0.1 μm, the adhesion between the elastomer layer 3 and the resin film 1 for the diaphragm of the speaker of a portable device is insufficient, resulting in a problem during molding into the diaphragm or during use. It is because there is a possibility that it may peel off. On the other hand, if the thickness of the primer exceeds 5 μm, it may adversely affect the secondary moldability of the diaphragm or the acoustic characteristics.

In this embodiment, the same effects as those in the above embodiment can be expected, and besides, the compression set property of the elastomer layer 3 is deteriorated, and the vibration propagation speed of the diaphragm of the portable device speaker is lowered, resulting in a problem of sound quality. Clearly it can be prevented from occurring.

Various types of antistatic agents, silicone resins, acrylic resins, urethane resins, and other elastomers are applied to the surface of the resin film 1 for the diaphragm of the portable device speaker of the above-described embodiment, as long as the effects of the present invention are not lost. Alternatively, various metals such as aluminum, tin, nickel, and copper may be deposited. A plurality of discs, meshes, etc., of the filter 16 are selectively laminated and used as required. Furthermore, the aperture shape of the filter 16 is not particularly limited to circular, elliptical, rectangular, polygonal, or the like.

Hereinafter, examples of the resin film for a diaphragm of a portable device speaker according to the present invention and a method for producing the same will be described together with comparative examples.
[Example 1]
First, a molding material was prepared from a crystalline thermoplastic polyimide resin and an adhesive fluororesin. As the crystalline thermoplastic polyimide resin, 100 parts by mass of commercially available Serprim TO-65 [manufactured by Mitsubishi Gas Chemical Co., Ltd.: product name, (hereinafter abbreviated as "TO-65")] is prepared, and this crystallinity was dried in a dehumidifying dryer heated to 160° C. for 12 hours. As the adhesive fluororesin, 5 parts by mass of commercially available adhesive fluororesin EA-2000 (manufactured by AGC: product name, hereinafter abbreviated as “EA-2000”) was prepared. The apparent shear viscosity of the thermoplastic polyimide resin and the adhesive fluororesin was evaluated by the apparent shear viscosity at a temperature of 350°C.

After preparing these, the two types of resins are put into a mixer and stirred and mixed to prepare a stirred mixture, and the stirred mixture is melt-kneaded with a co-rotating twin-screw extruder or the like and extruded into a strand shape, After the extrudate was solidified by water cooling, it was cut into pellets to prepare a molding material. A co-rotating twin-screw extruder of φ25 mm, L/D=41 type was used. The stirred mixture was melt-kneaded under conditions of a cylinder temperature of 200 to 350°C and a die temperature of 350°C to prepare a molding material. The temperature during melt-kneading was determined by measuring the temperature of the molding material in a molten state immediately after being extruded from the die.

Next, the molding material is put into a dehumidifying dryer heated to 160° C. and dried for 24 hours. The resulting molding material was continuously extruded from a T-die to extrusion-mold a resin film for a diaphragm of a portable device speaker into a belt shape. The single-screw extruder had a diameter of 20 mm and a screw: full-flight screw (L/D=25, compression ratio: 2.5) type. The temperature of the single-screw extruder was adjusted to 340 to 350°C, the temperature of the T-die was adjusted to 350°C, and the temperature of the connecting pipe connecting the single-screw extruder and the T-die and the temperature of the gear pump were each adjusted to 350°C. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 351°C.

After extruding the resin film for the diaphragm of the portable device speaker in this manner, the resin film for the diaphragm of the portable device speaker is applied to a pair of silicone rubber press rolls and a 150° C. cooling roll as shown in FIG. Rolls and a 3-inch winding tube of a winding machine located downstream of these are sequentially wound, sandwiched between a compression roll and a metal roll, and continuous both sides of a resin film for a diaphragm of a portable device speaker. was cut with a slit blade and successively wound around a winding tube to produce a resin film for a diaphragm of a portable device speaker having a length of 10 m and a width of 130 mm.

After manufacturing the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. The generation was measured, summarized in Table 1, and evaluated. The mechanical properties are the maximum tensile strength, elongation at break, and tensile elastic modulus of the resin film for the diaphragm of the speaker of portable equipment. It was evaluated by the loss tangent.

・Apparent shear viscosity of crystalline thermoplastic polyimide resin Measured using [product name manufactured by IMATEK]. Specifically, capillary die: φ1.0 mm × 16 mm (long die), φ1.0 mm × 0.25 mm (short die), barrel diameter: 15 mm, temperature: 350 ° C. Under the conditions, a crystalline thermoplastic polyimide resin 40 g of is put into the barrel, and the piston is pushed at a speed of 50 mm / min until the pressure reaches 0.9 MPa on the long die side and 0.3 MPa on the short die side. When the pressure reaches a predetermined value, leave it as it is for 6 minutes. held.

After that, the piston is pushed again at a speed of 50 mm/min until the pressure reaches 0.9 MPa on the long die side and 0.3 MPa on the short die side ^. , 2×10 ¹ , 3×10 ¹ , 5×10 ¹ , 8×10 ¹ , 1×10 ² , 3×10 ² , 8×10 ² sec ⁻¹ ), and the apparent shear viscosity is asked. The apparent shear viscosity of the crystalline thermoplastic polyimide resin was obtained by obtaining the apparent shear viscosity of the crystalline thermoplastic polyimide resin at an apparent shear rate of 1×10 ² sec ⁻¹ .

- Apparent shear viscosity of adhesive fluororesin The apparent shear viscosity of the adhesive fluororesin at a temperature of 350°C was measured using a flow tester. Specifically, 1.5 cm ³ of resin is filled in a cylinder at 350°C fitted with a die (diameter: 1 mm, length 10 mm), and a plunger with an area of 1.0 cm ² is attached to the top of this cylinder. When the temperature of the cylinder reached 350° C., it was preheated for 5 minutes, and immediately after this preheating, a load of 50 kgf was applied to melt out the adhesive fluororesin, and its apparent shear viscosity was measured. The measurement was performed three times, and the average value was taken as the apparent shear viscosity.

・Thickness of the resin film for the diaphragm of the portable device speaker The film thickness of the resin film for the diaphragm of the portable device speaker is measured using a micrometer (manufactured by Mitutoyo, product name: Coolant proof micrometer code MDC-25PJ). bottom. In the measurement, measurements were taken at five arbitrary points in the width direction (perpendicular direction to the extrusion direction) of the resin film for the diaphragm of the portable device speaker, and the average value was taken as the film thickness.

・Mechanical properties of the resin film for the diaphragm of the portable device speaker The mechanical properties of the resin film for the diaphragm of the portable device speaker shall be evaluated by measuring the maximum tensile strength, tensile elongation at break, and tensile modulus. bottom. Specifically, according to JIS K 6251, the extrusion speed and width direction were measured under conditions of a tensile speed of 50 mm/min, a temperature of 23° C.±2° C., and a relative humidity of 50% RH±5% RH. A test piece of JIS K6251 No. 2 was used. Five measurements were taken, and the average value was taken as the maximum tensile strength, tensile elongation at break, and tensile modulus.

・Slipperiness of resin film for diaphragm of portable device speaker The slipperiness of the resin film for diaphragm of portable device speaker was evaluated by measuring static friction coefficient and dynamic friction coefficient. These static friction coefficient and dynamic friction coefficient were measured according to JIS K7125-1999. Specifically, using a surface property measuring machine [product name: HEDON-14 manufactured by Shinto Kagaku Co., Ltd.], under an environment of 23 ° C. ± 2 ° C., 50% RH ± 5% RH, test speed: 100 mm / min , load: 200 g, contact area: 63.5 mm x 63.5 mm.

Then, the outer surface of the resin film for the diaphragm of the portable device speaker is fixed to the moving table side, the inner surface of the resin film for the diaphragm of the portable device speaker is fixed to the fixed table side, a load of 200 g is applied, and a load of 100 mm/min is applied. The static friction coefficient and dynamic friction coefficient were measured at speed respectively.

- Acoustic Characteristics of Resin Film for Diaphragm of Portable Device Speaker The acoustic characteristics of the resin film for diaphragm of portable device speaker were evaluated by measuring the loss tangent at 20°C. This loss tangent was measured in the extrusion direction and the width direction. Specifically, when measuring the loss tangent in the extrusion direction of the resin film, the size is 60 mm in the extrusion direction x 6 mm in the width direction, and when measuring the loss tangent in the width direction, the size is 6 mm in the extrusion direction x 60 mm in the width direction. was cut out and measured. When measuring the loss tangent, the tensile mode using a viscoelastic spectrometer (product name: RSA-G2 manufactured by TS Instrument Japan) was used at a frequency of 1 Hz, a strain of 0.1%, and a heating rate of 3. C./min, measurement temperature range -60.degree. C. to 360.degree.

・Occurrence of wrinkles during winding of the resin film for the diaphragm of the speaker of mobile devices during manufacturing Regarding the presence or absence of occurrence, after winding 100 m on the winding tube, it was visually observed and marked as ◯×. ◯ indicates that no wrinkles occurred, and x indicates that wrinkles occurred.

[Example 2]
In Example 1, the crystalline thermoplastic polyimide resin [Surprim TO-65] dried at 160 ° C. for 24 hours and the adhesive fluororesin of Example 1 [product name: EA-2000] were prepared, and the adhesion The fluororesin is weighed so as to be 10 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic polyimide resin, and then the two types of resin are put into a mixer and stirred for 1 hour at room temperature. A mixture was prepared.

Thereafter, the stirred mixture was charged into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. Regarding the temperature during melt kneading of the crystalline thermoplastic polyimide resin and the adhesive fluororesin, the temperature of the molten molding material immediately after being extruded from the die was measured.

Next, the molding material dried at 160 ° C. for 24 hours was put into the φ20 mm single screw extruder with a T die of 150 mm width used in Example 1 and melt-kneaded, and the melt-kneaded molding material was passed through the T die. By continuously extruding, a resin film for a diaphragm of a portable device speaker was extruded into a belt shape. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 350°C.

After extrusion-molding the resin film for the diaphragm of the portable device speaker in this manner, the resin film for the diaphragm is successively wound around a winding tube in the same manner as in Example 1, thereby producing a portable device having a length of 10 m and a width of 120 mm. We manufactured a resin film for speaker diaphragms. After manufacturing the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. Development was measured and reported in Table 1 and evaluated.

[Example 3]
In Example 1, the crystalline thermoplastic polyimide resin [Surprim TO-65] dried at 160 ° C. for 24 hours and the adhesive fluororesin of Example 1 [product name: EA-2000] were prepared, and the adhesion The fluororesin is weighed to 20 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic polyimide resin, and then the two types of resin are put into a mixer and stirred for 1 hour at room temperature. A mixture was prepared.

Thereafter, the stirred mixture was charged into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. Regarding the temperature during melt kneading of the crystalline thermoplastic polyimide resin and the adhesive fluororesin, the temperature of the molding material in a molten state immediately after being extruded from the die was measured.

Next, the molding material dried at 160 ° C. for 24 hours was put into the φ20 mm single screw extruder with a T die of 150 mm width used in Example 1 and melt-kneaded, and the melt-kneaded molding material was passed through the T die. By continuously extruding, a resin film for a diaphragm of a portable device speaker was extruded into a belt shape. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 354°C.

After extrusion-molding the resin film for the diaphragm of the portable device speaker in this manner, the resin film for the diaphragm is successively wound around a winding tube in the same manner as in Example 1, thereby producing a portable device having a length of 10 m and a width of 120 mm. We manufactured a resin film for speaker diaphragms. After manufacturing the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. Development was measured and reported in Table 1 and evaluated.

[Example 4]
In Example 1, the crystalline thermoplastic polyimide resin [Surprim TO-65] dried at 160 ° C. for 24 hours and the adhesive fluororesin of Example 1 [product name: EA-2000] were prepared, and the adhesion The fluororesin is weighed so as to be 50 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic polyimide resin, and then the two types of resin are put into a mixer and stirred and mixed for 1 hour at room temperature. A mixture was prepared.

Thereafter, the stirred mixture was charged into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. Regarding the temperature during melt kneading of the crystalline thermoplastic polyimide resin and the adhesive fluororesin, the temperature of the molding material in a molten state immediately after being extruded from the die was measured.

Next, the molding material dried at 160 ° C. for 24 hours was put into the φ20 mm single screw extruder with a T die of 150 mm width used in Example 1 and melt-kneaded, and the melt-kneaded molding material was passed through the T die. By continuously extruding, a resin film for a diaphragm of a portable device speaker was extruded into a belt shape. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 353°C.

After extruding the resin film for the diaphragm of the portable device speaker, the diaphragm resin film was successively wound around a winding tube in the same manner as in Example 1, thereby producing a portable device speaker having a length of 10 m and a width of 120 mm. was manufactured. After manufacturing the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. Development was measured and reported in Table 1 and evaluated.

[Example 5]
In Example 1, the crystalline thermoplastic polyimide resin [Surprim TO-65] dried at 160 ° C. for 24 hours and the adhesive fluororesin of Example 1 [product name: EA-2000] were prepared, and the adhesion After weighing the fluororesin so as to be 90 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic polyimide resin, the two types of resins are put into a mixer and stirred and mixed for 1 hour at room temperature to form a stirred mixture. was prepared.

Thereafter, the stirred mixture was charged into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. Regarding the temperature during melt kneading of the crystalline thermoplastic polyimide resin and the adhesive fluororesin, the temperature of the molten molding material immediately after being extruded from the die was measured.

Next, the molding material dried at 160 ° C. for 24 hours was put into the φ20 mm single screw extruder with a T die of 150 mm width used in Example 1 and melt-kneaded, and the melt-kneaded molding material was passed through the T die. By continuously extruding, a resin film for a diaphragm of a portable device speaker was extruded into a belt shape. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 353°C.

After extruding the resin film for the diaphragm of the portable device speaker, the diaphragm resin film was successively wound around a winding tube in the same manner as in Example 1, thereby producing a portable device speaker having a length of 10 m and a width of 120 mm. was manufactured. After manufacturing the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. Development was measured and reported in Table 2 and evaluated.

[Comparative Example 1]
The molding material was changed to crystalline thermoplastic polyimide resin only. As this crystalline thermoplastic polyimide resin, 100 parts by mass of TO-65 used in Example 1 was prepared, and this crystalline thermoplastic polyimide resin was dried for 12 hours in a dehumidifying dryer heated to 160 ° C. . After the crystalline thermoplastic polyimide resin was prepared and dried in this manner, the crystalline thermoplastic polyimide was introduced into the single-screw extruder having a width of 150 mm and a T-die of φ20 mm and was used in Example 1, and melt-kneaded. Then, the melt-kneaded molding material was continuously extruded from a T-die to extrusion-mold a resin film for a diaphragm of a portable device speaker into a belt shape.

After the resin film for the diaphragm of the portable device speaker is extruded, the resin film for the diaphragm is applied to a pair of silicone rubber pressing rolls, a metal roll as a cooling roll at 150° C., and a roll as shown in FIG. The film is sequentially wound on a 3-inch winding tube of a winding machine located downstream, sandwiched between a compression roll and a metal roll, and a continuous resin film for a speaker diaphragm of a portable device is sequentially wound on the winding tube. Thus, a resin film for a diaphragm of a portable device speaker having a length of 10 m and a width of 120 mm was manufactured.

After manufacturing the resin film for the diaphragm of the portable device speaker for comparison, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding when wound on the winding tube of this resin film for the diaphragm of the portable device speaker were measured. The occurrence of wrinkles was measured, described in Table 3, and evaluated.

[Comparative Example 2]
First, the crystalline thermoplastic polyimide resin dried at 160 ° C. for 24 hours in Example 1 and the adhesive fluororesin EA-2000 in Example 1 are prepared, and the adhesive fluororesin is a crystalline thermoplastic. A stirred mixture was prepared by weighing 150 parts by mass with respect to 100 parts by mass of the polyimide resin, then putting the two types of resins into a mixer and stirring and mixing at room temperature for 1 hour.

Thereafter, the stirred mixture was charged into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. Regarding the temperature during melt kneading of the crystalline thermoplastic polyimide resin and the adhesive fluororesin, the temperature of the molding material in a molten state immediately after being extruded from the die was measured.

Next, the molding material dried at 160 ° C. for 24 hours was put into the φ20 mm single screw extruder with a T die of 150 mm width used in Example 1 and melt-kneaded, and the melt-kneaded molding material was passed through the T die. By continuously extruding, a resin film for a diaphragm of a portable device speaker was extruded into a belt shape. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 353°C.

After the resin film for the diaphragm of the portable device speaker is extruded, the resin film for the diaphragm is applied to a pair of silicone rubber pressing rolls, a metal roll as a cooling roll at 150° C., and a roll as shown in FIG. The film is sequentially wound on a 3-inch winding tube of a winding machine located downstream, sandwiched between a compression roll and a metal roll, and a continuous resin film for a speaker diaphragm of a portable device is sequentially wound on the winding tube. Thus, a resin film for a diaphragm of a portable device speaker having a length of 10 m and a width of 120 mm was manufactured.

After manufacturing the resin film for the diaphragm of the portable device speaker for comparison, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding when wound on the winding tube of this resin film for the diaphragm of the portable device speaker were measured. The occurrence of wrinkles was measured, described in Table 3, and evaluated.

[Comparative Example 3]
First, a crystalline thermoplastic polyimide resin dried at 160 ° C. for 24 hours in Example 1 and a non-adhesive fluorine resin tetrafluoroethylene-perfluoroalkoxyethylene copolymer (hereinafter referred to as "PFA resin ”) to prepare a molding material. As the PFA resin, commercially available NEOFLON AP-210 [manufactured by Daikin Industries, Ltd.: product name (hereinafter abbreviated as "AP-210")] was used. This PFA resin was prepared in an amount of 15 parts by mass with respect to 100 parts by mass of the crystalline thermoplastic polyimide resin. Once these were prepared, the two resins were charged into a mixer and mixed to prepare a stirred mixture. The apparent shear viscosity of this AP-210 at a temperature of 350° C. was measured in the same manner as the measurement of the apparent shear viscosity of the adhesive fluororesin in Example 1.

After preparing the stirred mixture, the stirred mixture was put into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. The kneading temperature was determined by measuring the temperature of the molding material in a molten state immediately after being extruded from the die, and was 346°C.

Next, the molding material dried at 160 ° C. for 24 hours was put into the φ20 mm single screw extruder with a T die of 150 mm width used in Example 1 and melt-kneaded, and the melt-kneaded molding material was passed through the T die. By continuously extruding, a resin film for a diaphragm of a portable device speaker was extruded into a belt shape. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 353°C.

After manufacturing the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. It was decided to measure the development and record it in Table 3 for evaluation.

[Comparative Example 4]
First, a molding material was prepared from an amorphous thermoplastic polyimide resin and an adhesive fluororesin. A polyetherimide resin [polycondensate of 4,4′-[isopropylidenebis(P-phenyloxy)diphthalic dianhydride and m-phenylenediamine] was used as the amorphous thermoplastic polyimide resin. . Commercially available ULTEM 1010-1000-NB [manufactured by SABIC: product name (hereinafter abbreviated as "1010")] was used as the amorphous thermoplastic polytherimide resin. 100 parts by mass of 1010 was prepared and dried for 12 hours in a dehumidifying dryer heated to 160°C. The apparent shear viscosity of 1010 at 350° C. was measured in the same manner as for the crystalline thermoplastic polyimide resin of Example 1.

As the adhesive fluororesin, 10 parts by mass of EA-2000 used in Example 1 was prepared. After these were prepared, a stirred mixture was prepared by putting the two types of resins into a mixer and stirring and mixing them. After the stirred mixture was prepared in this manner, the stirred mixture was charged into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. The kneading temperature was determined by measuring the temperature of the molding material in a molten state immediately after being extruded from the die, and was 346°C.

Next, the molding material is put into a dehumidifying dryer heated to 160° C. and dried for 24 hours, and the dried molding material is put into the single-screw extruder with a T-die of 150 mm in width used in Example 1 and melted. The melt-kneaded molding material was continuously extruded from a T-die to extrusion-mold a belt-shaped resin film for a speaker diaphragm of a mobile device having a width of 130 mm and a length of 10 m. The same equipment as in Example 1 was used for the single-screw extruder and T-die. The temperature of the single-screw extruder was adjusted to 340 to 360°C, the temperature of the T-die was adjusted to 360°C, and the temperature of the connecting pipe connecting the single-screw extruder and the T-die was adjusted to 360°C. The temperature of the resin at the inlet of the T-die was measured and found to be 361°C.

After manufacturing the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. It was decided to measure the development and record it in Table 3 for evaluation.

[Comparative Example 5]
Polyetherimide resin [4,4'-[isopropylidenebis(P-phenyloxy)diphthalic dianhydride], which is a commercially available amorphous thermoplastic polyimide resin, from a crystalline thermoplastic polyimide resin. and p-phenylenediamine, manufactured by SABIC, product name: ULTEM CRS5001-1000-NB (hereinafter abbreviated as "CRS5001").

100 parts by mass of this CRS5001 was prepared, and this 5001 was dried in a dehumidifying dryer heated to 160° C. for 12 hours. The apparent shear viscosity of 5001 at 350° C. was measured in the same manner as for the crystalline thermoplastic polyimide resin of Example 1. As the adhesive fluororesin, 10 parts by mass of EA-2000 used in Example 1 was prepared. After these were prepared, a stirred mixture was prepared by putting the two types of resins into a mixer and stirring and mixing them.

After preparing the stirred mixture, the stirred mixture was put into the co-rotating twin-screw extruder used in Example 1, and a molding material was prepared in the same manner as in Example 1. The stirred mixture was melt-kneaded under conditions of a cylinder temperature of 200 to 360°C and a die temperature of 360°C to prepare a molding material. The temperature during melt-kneading was determined by measuring the temperature of the molding material in a molten state immediately after being extruded from the die.

Next, the molding material is put into a dehumidifying dryer heated to 160° C. and dried for 24 hours, and the dried molding material is put into the single-screw extruder with a T-die of 150 mm in width used in Example 1 and melted. After kneading, the melt-kneaded molding material was continuously extruded from a T-die to extrusion-mold a resin film for a diaphragm of a portable device speaker into a belt shape. The same single-screw extruder as in Example 1 was used as the single-screw extruder. The temperature of the single-screw extruder was adjusted to 350 to 365°C, the temperature of the T-die was adjusted to 365°C, and the connecting pipes connecting the single-screw extruder and the T-die were adjusted to 365°C. As for the temperature of the molten molding material, the temperature of the resin at the inlet of the T-die was measured, and it was 372°C.

After obtaining the resin film for the diaphragm of the portable device speaker, the film thickness, mechanical properties, slipperiness, acoustic properties, and winding wrinkles when wound on the winding tube of the resin film for the diaphragm of the portable device speaker are measured. The occurrence of was measured and described in Table 4 for evaluation.

〔evaluation〕
In each example, since the adhesive fluororesin was added to the crystalline thermoplastic polyimide resin, the loss tangent of the resin film for the diaphragm of the portable device speaker at 20° C. increased to 0.015 or more, and resonance occurred. We were able to obtain high-quality sound quality characteristics by suppressing the In addition, since it is prepared from a crystalline thermoplastic polyimide resin and an adhesive fluoropolymer resin, it is possible to obtain sufficient lubricity due to the decrease in the coefficient of static friction and the coefficient of dynamic friction. It was possible to prevent the occurrence of wrinkles when winding on the winder.

In addition, since the tensile modulus of elasticity is 1000 N/mm ² or more and 3000 N/mm ² or less, the resin film for the diaphragm of the portable device speaker has good handleability, and no problem occurred in molding the portable device speaker. Furthermore, it was confirmed that in addition to high-pitched sound characteristics, excellent low-pitched sound characteristics and good sound quality characteristics with reduced resonance were obtained.

On the other hand, in the case of Comparative Example 1, since no adhesive fluororesin was added, the static friction coefficient and the dynamic friction coefficient of the resin film for the diaphragm of the portable device speaker were high, and the loss tangent at 20° C. was 0.013. It was below. As a result, wrinkles were observed when the resin film for the diaphragm was wound on the winder, and resonance could not be suppressed, and good sound quality could not be obtained.

In the case of Comparative Example 2, since 150 parts by mass of the adhesive fluororesin was added to 100 parts by mass of the crystalline thermoplastic polyimide resin, the tensile elastic modulus of the resin film for the diaphragm of the portable device speaker was less than 1000 N/mm ² . However, the resin film for the diaphragm of the portable device speaker was poor in handleability, and a problem arose in the formability of the portable device speaker.

In the case of Comparative Example 3, the loss tangent at 20° C. was 0.014 or less for the resin film for the diaphragm of the portable device speaker to which the PFA resin, which is a non-adhesive fluororesin, was added. As a result, it was not possible to suppress the occurrence of resonance in the resin film for the diaphragm of the portable device speaker, and it was not possible to obtain good sound quality. Furthermore, in the case of Comparative Examples 4 and 5, since the amorphous thermoplastic polyimide resin was used, the tensile modulus exceeded 3000 N/mm ² and the F ₀ value increased, resulting in deterioration of the bass characteristics. could not be prevented.

INDUSTRIAL APPLICABILITY A resin film for a diaphragm of a portable device speaker and a method for producing the same according to the present invention are used in the field of manufacturing mobile phones, portable game devices, smart phones, and the like.

1 resin film for diaphragm 2 molding material 3 elastomer layer 10 melt extruder (extrusion molding machine)
13 T dice (dice)
17 compression roll 18 cooling roll 20 winder

Claims (4)

It is molded from a molding material containing 100 parts by mass of a crystalline thermoplastic polyimide resin and 1 part by mass or more and 100 parts by mass or less of an adhesive fluororesin, and the thermoplastic polyimide resin contains at least a tetracarboxylic component and an aliphatic diamine. The apparent shear viscosity of the adhesive fluororesin at 350° C. is 9×10 2 ^Pa s or more and 2×10 ⁴ Pa s or less under a load of 50 kgf,
52 N/mm ² or more and 68 N/mm ² or less when the maximum tensile strength at 23 ° C. is measured in accordance with JIS K 6251, and 170% when the tensile elongation at break is measured in accordance with JIS K 6251 230% or more, 1400 N/mm ² or more and 2250 N/mm ² or less when the tensile modulus at 23 ° C. is measured in accordance with JIS K 6251, and the static friction coefficient at 23 ° C. is in accordance with JIS K 7125-1999. 0.04 or more and 0.35 or less when measured, and 0.04 or more and 0.30 or less when the dynamic friction coefficient is measured in accordance with JIS K 7125-1999, and the loss tangent at 20 ° C. is 0.020. A resin film for a diaphragm of a loudspeaker for a mobile device, wherein the resin film is 0.45 or less . An elastomer layer having a thickness of 10 μm or more and 100 μm or less is sandwiched between a pair of diaphragm resin films. 2. The resin film for a diaphragm of a portable device speaker according to claim 1, having an A10 or more and an A90 or less. 3. The resin film for a diaphragm of a portable device speaker according to claim 1, wherein the diamine component of the thermoplastic polyimide resin is a linear aliphatic diamine having 4 to 12 carbon atoms. A method for manufacturing a resin film for a diaphragm of a portable device speaker according to claim 1, 2, or 3 ,
A molding material is prepared from 100 parts by mass of a crystalline thermoplastic polyimide resin and 1 part by mass or more and 100 parts by mass or less of an adhesive fluororesin, and the thermoplastic polyimide resin of the molding material contains at least a tetracarboxylic component and an aliphatic Diamine is a diamine component as a main component, and the apparent shear viscosity of the adhesive fluororesin at 350° C. is 9×10 2 ^Pa ·s or more and 2×10 ⁴ Pa·s or less under a load of 50 kgf,
The molding material is melt-kneaded and put into an extruder, and the molding material is extruded into a resin film for a diaphragm of a speaker of a portable device using the die of the extruder, and the resin film for a diaphragm is brought into contact with a cooling roll. 1. A method for producing a diaphragm resin film for a speaker of a mobile device, comprising: cooling the resin film for a diaphragm by a winding machine;

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