JP4793244B2 - Speaker dust cap - Google Patents

Description

  The present invention relates to a dust cap for speakers used in various audio equipment.

  As a speaker dust cap for a speaker used in an acoustic device, a speaker dust cap formed by pulping a fiber to form a speaker dust cap has been generally used for a wide range of applications. .

  With respect to recent electronic equipment such as audio equipment and video equipment, the performance has been dramatically improved as compared with the prior art due to remarkable progress in digital technology.

  Due to the performance improvement of these electronic devices, there is a strong demand from the market to improve the performance of speakers used in these electronic devices.

  In order to improve performance, which is strongly demanded by this market, it is indispensable to improve the performance of the speaker dust cap, which occupies a large weight that determines the sound quality of the speaker diaphragm. It has become. The demand for higher sound quality is particularly high in the performance enhancement of speaker dust caps, and the provision of a speaker dust cap that can achieve high sound quality is indispensable.

  A method for producing a speaker dust cap by paper making, which is a conventional speaker dust cap, will be described with reference to FIG.

  FIG. 2 is a flowchart showing a conventional method for manufacturing a speaker dust cap by papermaking.

  As shown in FIG. 2, the pulp which is the material of the speaker dust cap is put in a beater containing water and beaten finely for several days.

  Next, after passing through a chemical treatment process called input mixing of dyes, binders, fixing agents, etc., through a papermaking process consisting of a flow of papermaking tank input, dilution, dispersion, and papermaking, water is removed to some extent by the dehydration process which is the first half of the drying process. Evaporate, press heat and press in press process, further evaporate water and homogenize by press, and further, the outermost part that becomes unnecessary is punched out by a die in the second half process, and made by paper making A speaker dust cap is manufactured.

  If necessary, the sound quality adjusting agent is applied or impregnated by dipping or spraying between the pressing process and the punching process or after the punching process.

  Thus, the conventional speaker dust cap is completed.

  In addition, although the above demonstrated the manufacturing method of the dust cap for speakers which presses after papermaking, the non-press speaker dust cap which abbreviate | omitted the press process also exists.

  There is no significant difference in the method in which the sound quality adjusting agent is used even in the non-press speaker dust cap.

  The raw material for beating in FIG. 2 is unbleached pulp or bleached pulp that has been digested conventionally. Even if a speaker dust cap is manufactured from a fiber simply beaten by a beater or the like, the strength is low and the elastic modulus is low, and there are many problems in terms of strength and sound quality as a speaker dust cap.

  Various studies have been conducted to solve the above problems.

Patent Document 1 is known as prior art document information relating to the invention of this application.
JP-A-6-14391

  However, none of the conventional techniques is suitable for the above-mentioned high performance of the digitized audio equipment, and the present invention is suitable for high performance of the above-mentioned audio equipment, has little variation, has sufficient strength, The present invention provides a paper speaker dust cap with a high sound speed.

In order to achieve the above-mentioned object, the speaker dust cap of the present invention has a fiber trunk diameter of 30 μm or less, and promotes fluffing on the surface of the trunk, thereby fuzzing in a branch shape to a diameter of 1 μm or less. Bamboo fiber (hereinafter referred to as “A fiber”) at least 2 wt% or more. With the above-described configuration, it is possible to provide a speaker dust cap that can achieve high sound quality with higher internal sound and higher internal loss.

  The speaker of the present invention serves as a dust cap for speaker by papermaking that enables high sound quality. Providing a speaker using the same is useful for consumers, and its industrial value is very large.

  EXAMPLES Hereinafter, examples will be described as the best mode of the present invention and examples of the present invention, but the scope of the present invention is not limited at all.

  In the best mode of the present invention, the main fiber obtained from bamboo fiber is 80 wt% to 95 wt% of the total fiber amount, and the bamboo fiber corresponding to the A fiber is 5 wt% to 20 wt% of the total fiber amount. A dust cap for speakers is made by papermaking.

  In addition, the manufacturing method of the dust cap for speakers by papermaking is the same as the method demonstrated by the prior art.

  In the best mode, the A fiber has a diameter of 50% or more of the branch-like feathered portion of 300 nm or less, and the volume occupation ratio of the branch-like feathered portion in the A fiber may exceed 20%. preferable.

  If necessary, a sizing agent, a paper strength agent, a waterproofing agent, a pigment, and the like are used. The sound quality is adjusted by adding 3% to 10% of polylactic acid and / or raw rubber, respectively.

Example 1
A speaker dust cap containing 25 wt% of feathered bamboo fiber (formation of the A fiber by bamboo) was prepared with respect to 75 wt% of unbleached pulp obtained from conifers (650 ml beating degree). The speed of sound was 2100 m / s, and the internal loss was 0.035. Water drainage was slightly worse during production.

(Example 2)
The diameter of the trunk of the fiber is 30 μm or less with respect to the main fiber (beating degree 650 ml) obtained by beating bamboo fiber with a high-speed mixer. By promoting feathering of the surface of the trunk, the diameter is 1 μm or less. A dust cap for a speaker containing 5 wt% of fluffed bamboo fiber (formation of the A fiber by bamboo) was prepared. The sound velocity was 2380 m / s and the internal loss was 0.033.

  FIG. 1 shows a 10,000 times micrograph of the fibers of the main part of the speaker dust cap in this example.

(Comparative Example 1)
A dust cap for a speaker was prepared by containing 10 wt% of aramid pulp in 90 wt% of unbleached pulp obtained from softwood pulp (degree of beating 650 ml). The speed of sound was 1950 m / s, and the internal loss was 0.028.

  As described above, by mixing the A fiber, it was confirmed that the internal loss was higher than that of the conventional dust cap for speaker of papermaking, and the following was confirmed.

  That is, the effect is small when the dust cap for speakers contains less than 2 wt% of the A fiber.

  Preferably, it is 3 wt% or more and 50 wt% or less, but even if it contains 50 wt% or more, the effect is not improved, and most preferably 5 wt% or more and 20 wt% or less.

  When 5 wt%, not only the strength and elastic modulus are increased, but also the variation in the physical properties of the speaker dust cap is reduced as compared with the case of 3 wt%.

  On the other hand, if it exceeds 20 wt%, not only the improvement in strength and elastic modulus becomes very small, but also water will be lost during dehydration, making it difficult to produce.

  In addition, there is no particular limitation as long as the fiber trunk is a natural fiber of 30 μm or less, but bamboo fiber is desirable in terms of facilitating surface feathering. In this case, the method using a high-pressure homogenizer is the most preferable. effective.

  It was also confirmed that the feather diameter on the trunk surface of the feathered fiber was 1 μm or less. If it exceeds 1 μm, the fiber entanglement is small when producing a dust cap for a paper speaker, and the strength cannot be obtained.

  Furthermore, it was confirmed that 50% or more of the diameter of the branch portion on the surface of the A fiber is 500 nm or less, which is more effective and more preferable. Most preferably, when the diameter of 50% or more of the branch-like portion is 300 nm or less, it was confirmed that the rigidity was further increased when the speaker dust cap was formed (based on the result of visual measurement using an electron microscope).

  The amount of the component to be blended in the speaker dust cap at the time of manufacture differs depending on the ratio of the A fiber trunk and the branch-like feather part, but when the feather part is 20% or less in volume, the component Even if a large amount of is added, the strength and elastic modulus of the speaker dust cap do not improve much. Further, when the feather part is 50% or more in volume, the feather part becomes large, so that the effect of fiber entanglement becomes small.

  The volume ratio of the trunk portion and the feathered portion of the A fiber is preferably 4/1 or more and 1/1 or less, although it varies somewhat depending on the blending ratio of the fiber other than the A fiber and the A fiber. The measurement is based on the result of visual observation per unit based on an electron micrograph.)

  The method for producing feathering of the A fiber of the present invention is not particularly defined, but a method of using a disc refiner, a Jordan or a beater, a method of producing with a stone mortar capable of applying a large shearing force, etc. It is possible to apply a known method such as a method of manufacturing with a pressure homogenizer having both a large shearing force due to a collision and a feathering promotion effect caused by a pressure difference.

  The present invention requires a pulp other than the above components, but it may be a chemical fiber or a natural fiber. However, the strength and elastic modulus of the speaker dust cap are improved, and the environment (rapidly growing natural fiber can be supplied continuously From the viewpoint of resources, bamboo fiber is preferred. That is, it was confirmed that the most preferred form is a combination of bamboo fiber as the main fiber and bamboo fiber as the component.

  An additive may be added to the speaker dust cap of the present invention as necessary. The addition of existing sizing agents, paper strength agents, dyes and the like is not limited, but polylactic acid and raw rubber are preferred from the viewpoint of environmentally friendly additives. Polylactic acid is preferable in terms of improving the rigidity of the speaker dust cap, and raw rubber is preferable in terms of increasing internal loss.

  The dust cap for speakers made of paper according to the present invention and the speaker obtained therefrom are very useful because they satisfy the high sound quality required from the market. In addition, the use of bamboo fiber, which is the best in the present invention, is friendly to the global environment.

10,000 times micrograph of the essential fiber of the present invention Flow chart showing the manufacturing method of speaker dust cap by papermaking

Claims (6)

A speaker dust cap made of paper having a trunk diameter of 30 μm or less and containing 2 wt% or more of bamboo fibers having a trunk surface fluffed into a diameter of 1 μm or less. The speaker dust cap according to claim 1, wherein 50% or more of the portion fluffed in a branch shape with a diameter of 1 µm or less has a diameter of 500 nm or less. The speaker dust cap according to claim 1 or 2, wherein the volume of the portion fluffed in a branch shape on the surface of the fiber trunk occupies 20% or more. Diameter stem is at 30μm or less, according to claim 1 or claim 2 or claim 3 main component in the fiber component other than bamboo fibers fluffed to branch the surface of the trunk below the diameter of 1μm is bamboo fiber The dust cap for speakers described in 1. A speaker dust cap comprising polylactic acid in the speaker dust cap according to claim 1, claim 2, claim 3 or claim 4 . Claim 1 or claim 2 or claim 3 or speaker dust cap which contains the raw rubber speaker dust cap according to claim 4.