JP2010043390A - Edge material for speakers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an edge material for speakers which is excellent in elasticity and has high water-proof properties. <P>SOLUTION: The edge material for speakers is obtained by laminating a sheet with a continuous fiber nonwoven fabric, which sheet is provided by applying an elastic polymer to a nonwoven fabric provided by entangling bundles of ultrafine fibers of average fiber diameter of 0.3-7.0 μm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a speaker edge material for holding and controlling the operation of a diaphragm at the outer peripheral portion of the speaker diaphragm.

  The speaker edge is used on the outer peripheral portion of the diaphragm to control the holding and operation of the speaker diaphragm. The properties required of the material include no vertical / horizontal anisotropy, light weight, elasticity, and a large mechanical internal loss (tan δ). In order to satisfy the above, a sheet-like product obtained by adding a resin to a nonwoven fabric made of ultrafine fibers has been suitably used (Patent Documents 1 and 2).

However, since these materials have a low apparent density, they have high water absorption characteristics, and for example, it has been difficult to use them as in-vehicle speakers that are highly likely to come into contact with water. In response to this problem, Patent Document 3 discloses a speaker edge in which one side or both sides are covered with an elastomer such as rubber. However, by having a rubber-like layer, there is a problem that the lightness and stretchability inherently possessed by the base material are impaired.
Japanese Patent Laid-Open No. 07-184295 Japanese Patent Laid-Open No. 11-308695 JP 2007-266721 A

An object of the present invention is to provide an edge for a speaker that has excellent stretchability and high waterproofness.

  That is, the present invention is formed by laminating a sheet-like material in which an elastic polymer adheres to a nonwoven fabric formed by entanglement of a bundle of ultrafine fibers having an average fiber diameter of 0.3 to 7.0 μm and a long fiber nonwoven fabric. This is an edge material for speakers.

  ADVANTAGE OF THE INVENTION According to this invention, the edge for speakers which has both the elasticity and waterproofness which was difficult to achieve conventionally can be provided.

  The speaker edge material of the present invention has a sheet-like material in which an elastic polymer is attached to a non-woven fabric in which bundles of ultrafine fibers are entangled (hereinafter also referred to as “ultrafine fiber bundle non-woven fabric”).

  Examples of the polymer forming the ultrafine fiber include polyester, polyamide, and polyolefin. Of these, polycondensation polymers represented by polyesters and polyamides are preferred because many have high melting points and durability. Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, and potytrimethylene terephthalate. Specific examples of the polyamide include nylon 6, nylon 66, and nylon 12. In addition, other components may be copolymerized in the polymer. The polymer may contain additives such as particles, flame retardants, antistatic agents and the like.

  It is important that the average fiber diameter of the ultrafine fibers is 0.3 to 7.0 μm. By setting the thickness to 7.0 μm or less, preferably 5.0 μm or less, good surface quality can be obtained. On the other hand, when the thickness is 0.3 μm or more, preferably 0.5 μm or more, an internal loss (tan δ) necessary for the speaker edge can be obtained, and sufficient strength can be maintained as the speaker edge.

  As a form of the bundle of ultrafine fibers, the single fibers may be separated, may be partially bonded, or may be aggregated.

  The ultrafine fiber bundle nonwoven fabric is preferably a short fiber nonwoven fabric because of its low vertical / horizontal anisotropy and good quality.

  The elastic polymer in the sheet-like material of the speaker edge material of the present invention contributes to maintaining the shape of the speaker edge and imparting appropriate rigidity and cushioning properties.

  Examples of the elastic polymer include polyurethane, polyurea, polyurethane / polyurea elastomer, polyacrylic acid, acrylonitrile / butadiene elastomer, and styrene / butadiene elastomer.

  Among these, polyurethane elastomers such as polyurethane and polyurethane / polyurea elastomer are preferable. As the polyol component of the polyurethane-based elastomer, polyester-based, polyether-based, polycarbonate-based diols, or copolymers thereof can be used. Moreover, as a diisocyanate component, aromatic diisocyanate, alicyclic isocyanate, aliphatic isocyanate, etc. can be used.

  The weight average molecular weight of the polyurethane is preferably 50,000 to 300,000. By maintaining the weight average molecular weight at 50,000 or more, more preferably 100,000 or more, and even more preferably 150,000 or more, the strength of the sheet-like material and the speaker edge can be maintained, and the extra fine fibers can be prevented from falling off. Can do. Moreover, by making it 300,000 or less, More preferably, it is 250,000 or less, the increase in the viscosity of a polyurethane solution can be suppressed and it can make it easy to impregnate a microfiber bundle nonwoven fabric.

  The elastic polymer may contain an elastomer resin such as polyester, polyamide, or polyolefin, an acrylic resin, an ethylene-vinyl acetate resin, or the like.

  In addition, additives such as colorants, antioxidants, antistatic agents, dispersants, softeners, coagulation modifiers, flame retardants, antibacterial agents, and deodorants are blended in the elastic polymer as necessary. Also good.

  The content of the elastic polymer is preferably 5 to 200% by mass with respect to the ultrafine fiber bundle nonwoven fabric. The surface state, cushioning property, hardness, strong elongation, etc. of the speaker edge can be adjusted by the content. By setting the content to 5% by mass or more, more preferably 20% by mass or more, and further preferably 30% by mass or more, fiber dropout can be reduced. On the other hand, by making it 200% by mass or less, more preferably 100% by mass or less, and further preferably 80% by mass or less, workability and productivity are improved, and a state in which ultrafine fibers are sufficiently dispersed on the surface is obtained. be able to.

  In the speaker edge material of the present invention, it is preferable that the surface on the opposite side of the lamination of the sheet-like material including the ultrafine fiber bundle nonwoven fabric with the long fiber nonwoven fabric described later has napped fibers made of ultrafine fibers. By doing so, surface quality can be improved and internal loss as a speaker edge can be improved.

  It is important that the edge material for a speaker of the present invention is formed by further laminating a long-fiber non-woven fabric on a sheet-like material including the ultrafine fiber bundle non-woven fabric as described above. The long-fiber non-woven fabric can impart water repellency to the speaker edge without impairing the stretchability of the sheet-like material including the ultra-fine fiber bundle non-woven fabric.

  From the viewpoint of imparting water repellency, polyolefin is preferably used as the polymer that forms the fibers of the long-fiber nonwoven fabric. As an example of polyolefin, polyethylene, polypropylene, or the like can be employed.

  As the long-fiber nonwoven fabric, the melt-blown nonwoven fabric has an appropriate elongation and does not impair the properties of the ultra-fine fiber bundle nonwoven fabric. It is preferable because it is easy to adopt.

  As an average fiber diameter of the fiber of a long-fiber nonwoven fabric, 0.01-50 micrometers is preferable. By setting the thickness to 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less, the uniformity of basis weight is excellent. On the other hand, by setting the thickness to 0.01 μm or more, more preferably 0.1 μm or more, and further preferably 0.5 μm or more, the strength of the long-fiber nonwoven fabric can be maintained, and the number of intersections between the fibers increases to increase the air permeability. The waterproofness is improved by lowering.

The basis weight of the long-fiber nonwoven fabric, 40 and 80 g / ^{m 2} is preferred. By setting it to 40 g / m ² or more, sufficient water repellency can be imparted to the sheet. On the other hand, by setting it to 80 g / m ² or less, more preferably 70 g / m ² or less, the stretchability of the sheet can be maintained.

The basis weight of the speaker edge material of the present invention is preferably 100 to 600 g / m ² . By setting it to 100 g / m ² or more, more preferably 150 g / m ² or more, the shape and dimensional stability of the speaker edge are excellent. On the other hand, when it is 600 g / m ² or less, and more preferably 300 g / m ² or less, it is excellent in attachment workability to a speaker.

  Moreover, as thickness of the edge material for speakers of this invention, 0.2-10 mm is preferable. When the thickness is 0.2 mm or more, preferably 0.3 mm or more, the shape and dimensional stability of the speaker edge are excellent. On the other hand, when the thickness is 10 mm or less, more preferably 5 mm or less, the processability to attach to the speaker is excellent.

  The edge material for a speaker of the present invention preferably has an elongation at break after pressing at a temperature of 170 ° C. and a pressure of 0.5 MPa in a vertical direction and a horizontal direction of 50 to 150%. By setting it to 50% or more, sufficient followability can be maintained, and by setting it to 150% or less, the shape retention characteristics of the speaker edge can be ensured.

The speaker edge material of the present invention is JIS L 1092: 1998 6.1. After being pressed at a temperature of 170 ° C. and a pressure of 0.5 MPa. It is preferred water pressure resistance by the method A is 30~150cmH ₂ O. It is possible to obtain sufficient waterproof With 30 cm H ₂ O or more. On the other hand, by a 150cmH 2 _O or less, it is possible to retain the properties of the substrate stretch or the like.

  Next, a method for producing the speaker edge material of the present invention will be described.

  As a means for obtaining an ultrafine fiber bundle nonwoven fabric, it is preferable to use an ultrafine fiber generating fiber. Although it is difficult to produce an ultrafine fiber bundle nonwoven fabric directly from an ultrafine fiber, an ultrafine fiber bundle is produced by producing a nonwoven fabric from an ultrafine fiber generating fiber and generating the ultrafine fiber from the ultrafine fiber generating fiber in the nonwoven fabric. A nonwoven fabric can be obtained.

  As ultrafine fiber generation type fibers, two-component thermoplastic resins with different solvent solubility are used as sea components / island components, and the sea components are dissolved and removed using a solvent to remove island components into ultrafine fibers. It is possible to employ a peelable composite fiber that splits into ultrafine fibers by disposing two or more components of thermoplastic resin alternately in a radial or multilayer manner on the fiber cross section and separating and separating each component.

  Sea-island type fibers include sea-island type composite fibers that use a sea-island type composite base to spun two sea and island components together, and mixed spinning fibers that mix and spin the two sea and island components. However, sea-island type composite fibers are more preferable because ultrafine fibers having a uniform fineness can be obtained, and a sufficiently long ultrafine fiber can be obtained and contribute to the strength of the sheet-like material.

  As the sea component of the sea-island type fiber, it is possible to use polyethylene, polypropylene, polystyrene, copolymer polystyrene, copolymer polyester, polylactic acid, thermoplastic PVA-based resin, etc. having a copolymer component such as sodium sulfoisophthalic acid or polyethylene glycol. it can.

  The sea component may be dissolved and removed at any timing before the elastic polymer is applied, after the elastic polymer is applied, or after the raising treatment.

As a method for obtaining a nonwoven fabric, a method of entanglement of a web with a needle punch or a water jet punch, a spun bond method, a melt blow method, a paper making method, or the like can be employed.
Among these, those that undergo treatment such as needle punching and water jet punching are preferred in order to increase the entanglement of the fibers to impart sufficient strength to the nonwoven fabric and improve the quality of the nonwoven fabric.

  In the needle punching process, the number of barbs is preferably 1 to 3. By using one or more fibers, efficient fiber entanglement becomes possible. On the other hand, fiber damage can be suppressed by setting it to 3 or less.

The number of needle punches is preferably 500 to 8000 / cm ² . By setting it to 500 lines / cm ² or more, denseness can be obtained, and a highly accurate finish can be obtained. On the other hand, by setting it to 8000 pieces / cm ² or less, deterioration of workability, fiber damage, and strength reduction can be prevented.

  Moreover, when performing a water jet punch process, it is preferable to perform water in the state of a columnar flow. Specifically, water may be ejected from a nozzle having a diameter of 0.05 to 1.0 mm at a pressure of 1 to 60 MPa.

The apparent density of the ultrafine fiber-generating fiber nonwoven fabric after needle punching or water jet punching is preferably 0.15 to 0.30 g / cm ³ . By setting it to 0.15 g / cm ³ or more, the shape stability and dimensional stability of the polishing cloth are excellent, and the occurrence of processing unevenness and scratch defects due to the elongation of the polishing cloth during polishing processing can be suppressed. On the other hand, by setting it to 0.30 g / cm ³ or less, a sufficient space for imparting the elastic polymer can be maintained.

  From the viewpoint of densification, the ultrafine fiber generating fiber nonwoven fabric obtained in this way is preferably shrunk by dry heat or wet heat, or both, and further densified.

  Solvents that dissolve easily soluble polymers (sea components) from ultrafine fiber-generating fibers are organic solvents such as toluene and trichlorethylene in the case of polyolefins such as polyethylene and polystyrene, and sodium hydroxide in the case of polylactic acid and copolymer polyesters. In the case of an alkaline aqueous solution such as a thermoplastic PVA resin, hot water can be used. The ultrafine fiber generation processing (sea removal treatment) can be performed by immersing the ultrafine fiber generation fiber nonwoven fabric in a solvent and squeezing it.

  The ultrafine fiber generation processing may be performed before the napping treatment or after the napping treatment.

  The elastic polymer may be applied before or after the ultrafine fiber generation processing.

  As the solvent used for imparting the elastic polymer, N, N′-dimethylformamide, dimethyl sulfoxide and the like can be preferably used. Alternatively, an aqueous polyurethane dispersed as an emulsion in water may be used.

  The elastic polymer is applied to the non-woven fabric by immersing the non-woven fabric in an elastic polymer solution dissolved in a solvent, and then dried to substantially solidify and solidify the elastic polymer. In drying, you may heat at the temperature which does not impair the performance of a nonwoven fabric and an elastic polymer.

  The napping treatment can be performed using sandpaper, a roll sander or the like. Furthermore, in order to form uniform napping on the surface of the speaker edge material, it is preferable to reduce the grinding load. In order to reduce the grinding load, for example, it is more preferable that the number of buff stages is multistage buffing with three or more stages, and the number of sandpaper used in each stage is in the range of 150 to 600 of JIS regulations.

  As a method of laminating the long fiber nonwoven fabric on the sheet-like material containing the ultrafine fiber bundle nonwoven fabric, for example, there is a method of collecting and integrating the long fibers directly on the sheet material containing the ultrafine fiber bundle nonwoven fabric by the melt blow method. From the viewpoints of processability, adhesiveness and the like.

  In use, the speaker edge material is subjected to hot press molding. The conditions for press molding can be appropriately changed depending on the design of the speaker edge. The mold temperature is preferably 100 to 180 ° C., the pressing pressure is 0.1 to 1.0 MPa, and the heating time is preferably 5 to 40 seconds.

[Measurement method and evaluation method]
(1) Melting point
Using a Perkin Elmaer DSC-7, the peak top temperature indicating the melting of the polymer at 2nd run was taken as the melting point of the polymer. At this time, the rate of temperature increase was 16 ° C./min, and the sample amount was 10 mg.

(2) Melt flow rate (MFR)
Sample pellets 4 to 5 g are put in a cylinder of an MFR electric furnace, and are loaded for 10 minutes from an orifice having a vertical hole with an outer diameter of 9.5 mm, an inner diameter of 2.0955 mm, and a height of 8 mm under the conditions of a load of 325 gf and a temperature of 270 ° C. The amount of resin extruded (g) was measured. The same measurement was repeated 3 times, and the average value was defined as MFR.

(3) Average fiber diameter of ultrafine fibers A cross section parallel to the thickness direction of the nonwoven fabric was observed with a scanning electron microscope (VE-7800 manufactured by SEM KEYENCE) at a magnification of 3000 times, and randomly within a field of view of 30 μm × 30 μm. The diameters of 50 single fibers extracted in the above were measured. This was performed at three locations, and the average value of the diameters of a total of 150 single fibers was calculated.
When the ultrafine fiber has an irregular cross section, first, the cross section of the single fiber is measured, and the diameter of the single fiber is obtained by calculating the diameter of a circle having the same area as the cross section.

(4) Weight per unit area Measured according to JIS L 1906: 2000.
Three test pieces each having a size of 20 cm × 20 cm were sampled, each mass (g) was measured, and the average value was expressed as a mass per 1 m ² (g / m ² ).

(5) Thickness Measured according to JIS L 1096: 1999 8.5 applied mutatis mutandis to JIS L 1906: 2000.
Thickness was measured after waiting for 10 seconds under a pressure of 23.5 kPa using a thickness measuring machine (“Peacock” (registered trademark) H manufactured by Ozaki Mfg. Co., Ltd.) at five different locations of the sample. The average value was calculated.

(6) Apparent density The apparent density was determined by dividing the basis weight value measured above by the thickness value.

(7) Press treatment The speaker edge material was pressed with a pair of flat rolls made of steel and having a roll diameter of 60 cm at a roll temperature of 170 ° C., a press pressure of 0.5 MPa, and a feed rate of 0.5 m / min.

(8) Elongation at break Measured according to JIS L 1906: 2000.
Twenty sample pieces each having a width of 1 cm and a length of 20 cm were collected for each of the vertical direction and the horizontal direction of the speaker edge material subjected to the press treatment.
The sample piece is attached to a constant-speed extension tensile tester with a gripping interval of 10 cm in a state where the sample piece is pulled to the extent that sagging does not occur. Was the elongation at break, and the average value was calculated for each of the vertical and horizontal directions.

(9) Water pressure resistance (low water pressure method)
JIS L 1092: 1998 6.1. It measured according to A method (low water pressure method).
Five test pieces of 15 cm × 15 cm were collected from the speaker edge material subjected to the above-mentioned press treatment, and attached to the water resistance test apparatus so that the long fiber non-woven fabric was in contact with the water, and the water was applied to the long fiber non-woven fabric side. Raise the inserted level device at a speed of 10 cm / min to raise the water level, measure the water level when water comes out from three places on the back side of the test piece, and calculate the average value of the five measurement results did.

(10) tan δ
It was measured by the vibration lead method.

[Example 1]
(Sheet containing ultrafine fiber bundle nonwoven fabric)
PET having a melting point of 263 ° C. and MFR 2.5 was used as an island component, and polystyrene having a melting point of 87 ° C. and MFR 18 was used as a sea component.
Using the above sea and island components, a 36 island / hole sea-island type composite die, spinning temperature 285 ° C., island / sea mass ratio 55/45, discharge rate 1.2 / min / hole, spinning speed 1240 m / Melt spun in minutes. Next, it is stretched 3.5 times in a 90 ° C. liquid bath, crimped by an indentation type crimper, cut, and a raw material of sea-island type composite fiber having a fineness of 2.9 dtex and a fiber length of 51 mm is obtained. Obtained.
Using the raw cotton, a laminated web was formed through a card and a cross wrapper process. Next, needle punching was performed with a needle punching machine having a total barb depth of 0.08 mm and a 1 barb needle implanted at a needle depth of 7 mm and a punch count of 3000 / cm ² , with a basis weight of 595 g / m ² and an apparent density of 0.23 g. An ultrafine fiber generating fiber nonwoven fabric of / cm ³ was produced.
The ultrafine fiber generating fiber nonwoven fabric was subjected to hot water shrinkage at 95 ° C., and then 24% by mass of polyvinyl alcohol was added to the fiber mass, and then dried.
To this non-woven fabric, polyurethane having a polymer diol of 75% by mass of polyether and 25% by mass of polyester is added in a solid content of 23% by mass with respect to the mass of the fiber, and 30% N, N- at a liquid temperature of 35 ° C. The polyurethane was coagulated with an aqueous dimethylformamide (DMF) solution, and DMF and polyvinyl alcohol were removed with hot water at about 85 ° C.
Then, the half-cut surface was half-cut with a half-cutting machine having an endless band knife, and the non-half cut surface was ground in three stages with JIS # 320 sandpaper to form napped hairs.
Subsequently, it is dyed with a liquid dyeing machine at a temperature of 120 ° C. for 45 minutes at a liquid dyeing machine with a blue dye (“Sumikaron” Blue S-BBL200 manufactured by Sumika Chemtex Co., Ltd.) 20% owf. It dried and obtained the sheet-like material containing a microfiber bundle nonwoven fabric.
The sheet-like product had an average fiber diameter of ultrafine fibers of 2.1 μm, a thickness of 0.51 mm, a basis weight of 172 g / m ² , and an apparent density of 0.337 g / cm ³ .

(Edge material for speakers)
MFR800 polypropylene was melted, and a discharge amount of 300 g / min, nozzle temperature of 280 ° C., air temperature from a base of a 1200 mm wide melt blown cloth device in which discharge holes 1201 having a diameter of 0.4 mm were arranged in a straight line with a hole pitch of 1 mm, air temperature of 280 ° C., air Injected at a pressure of 0.05 MPa, the polypropylene fibers are collected on the sheet-like material that is placed on the collecting conveyor of the melt-blow cloth making apparatus and runs at 5.5 m / min, and has a basis weight of 45 g / m ² . A meltblown nonwoven fabric was laminated and integrated to obtain a speaker edge material.

[Example 2]
(Sheet containing ultrafine fiber bundle nonwoven fabric)
The same one as used in Example 1 was used.

(Edge material for speakers)
An edge material for a speaker was produced in the same manner as in Example 1 except that the basis weight of the melt blown nonwoven fabric was changed to 65 g / m ² by setting the traveling speed of the sheet-like material to 3.8 m / min.

[Comparative Example 1]
(Sheet containing ultrafine fiber bundle nonwoven fabric)
The same one as used in Example 1 was used.

(Edge material for speakers)
The long fiber nonwoven fabric was not laminated, and the sheet-like material containing the above-mentioned ultrafine fiber bundle nonwoven fabric was used as an edge material for speakers.
The obtained speaker edge material has low water pressure resistance and cannot be applied to a vehicle-mounted speaker that is required to be waterproof.

[Comparative Example 2]
(Sheet containing ultrafine fiber bundle nonwoven fabric)
The same one as used in Example 1 was used.

(Edge material for speakers)
The long fiber nonwoven fabric was not laminated, but instead, SBR (styrene butadiene rubber) having a basis weight of 50 g / m ² was laminated and integrated by calendering to obtain a speaker edge material.
Since the obtained speaker edge material had a low elongation at break, the workability and followability to vibration were poor, and it was not suitable for use.

Claims (5)

A sheet-like material in which an elastic polymer is attached to a nonwoven fabric obtained by entanglement of a bundle of ultrafine fibers having an average fiber diameter of 0.3 to 7.0 μm and a long-fiber nonwoven fabric are laminated. Edge material for speakers. The speaker edge material according to claim 1, wherein the long fiber nonwoven fabric is a melt blown nonwoven fabric. The speaker edge material according to claim 1 or 2, wherein the long-fiber nonwoven fabric is made of polyolefin fibers. The speaker edge material according to any one of claims 1 to 3, wherein an average fiber diameter of fibers constituting the long fiber nonwoven fabric is 0.01 to 50 µm. JIS L 1092: 1998 6.1. After press treatment at a temperature of 170 ° C. and a pressure of 0.5 MPa. Water pressure due A method is 30~150cmH ₂ O, loudspeaker edge material according to claim 1.