JP2007127908A - Sound absorbing film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sound absorbing film satisfying both transparency and sound absorbency. <P>SOLUTION: The sound absorbing film is configured in such a way that a transparent or translucent air permeable film 1 in which a plurality of vent holes 4 penetrating the film from the surface to the backside are interspersed and a translucent or translucent base material film 2 are laminated and bonded a specified gap away from each other via tacky adhesive layers provided in a linear and/dotty form, and air layers 5 communicating the tacky adhesive layers and the vent holes are disposed between both the films. It is preferable that the thickness of the tacky adhesive layer 3 is ≤5 mm and a tacky adhesive agent forming the tacky adhesive layer has a loss tangent of ≥0.50 by linear viscoelasticity measurement at 23°C. The area of the junctions by the tacky adhesive layers between the air permeable film 1 and the base material film 2 is preferably 10 to 70% of the entire area of the film 1 or film 2 on the tacky adhesive layer 3 side. Preferably, the thickness of the air permeable film 1 is 10 to 200 μm, the aperture ratio of the vent holes 4 is 3 to 50%, and the thickness of the base material film 2 is ≥30 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sound-absorbing film having both transparency and sound-absorbing property.

  Conventionally, in order to reduce noise, the sound absorbing material has been applied to various uses as a member of a house, a railway vehicle, an aircraft, a vehicle, and the like, and has very high needs. Examples of materials that absorb sound include porous materials such as glass wool and rock wool, and perforated plate structures such as perforated gypsum board and perforated hard board, for example, specific dynamic viscoelasticity and density. A sound-absorbing material using a highly sound-insulating material as a sound-absorbing material (Patent Document 1) made of a synthetic resin film molded body, or between a polymer film having micro-perforations and an object that requires sound-proofing Such as a polymer film sound absorbing material having a void (Patent Document 2), a sound insulating material having a specific density sound absorbing layer and a porous resonance layer made of a non-breathable material through an adhesive layer (Patent Document 3), etc. Numerous sound absorbing materials have been developed, including soundproofing structures that are characterized by the processing and arrangement of soundproofing materials.

  By the way, in recent years, the range in which the sound absorbing material is required is expanded due to noise problems and various functions are required for the sound absorbing material. One of them is transparency. For example, when considering increasing the soundproofing effect of the entire room, the sound absorption of the window glass as the opening is very important, and the window glass is required to have original transparency in addition to the sound absorbing effect. However, conventionally, a sound-absorbing material having both sound-absorbing properties and transparency, particularly a sound-absorbing film that can be easily applied and has excellent transparency has not yet been put to practical use.

JP 2001-272985 A JP 2002-521722 A JP 2005-121994 A

  The present invention provides a sound absorbing film having both transparency and sound absorbing property.

  The present inventors provide the above-mentioned transparent film by providing an adhesive layer and an air layer made of an adhesive having a specific linear viscoelasticity between a breathable transparent film having a vent hole on one side and a base film. The inventors have found that the object can be achieved and have completed the present invention.

The sound-absorbing film of the present invention comprises a transparent or translucent breathable film in which a plurality of air holes penetrating from the front surface to the back surface are scattered, and a transparent or translucent base film, with a certain amount interposed therebetween via an adhesive layer. The pressure-sensitive adhesive layer is provided in a linear or / and dot shape, and an air layer that communicates the pressure-sensitive adhesive layer and the air hole is provided between both films. To do.
Moreover, it is preferable to use the adhesive whose thickness of the said adhesion layer is 5 mm or less and whose loss tangent by the linear viscoelasticity measurement at 23 degreeC is 0.50 or more as an adhesive which forms the said adhesion layer.
Furthermore, in the said adhesion layer, it is preferable that the area of the junction part by the adhesion layer of the said air permeable film and the said base film is 10-70% of a film area.
Furthermore, it is preferable that the thickness of the air permeable film is 10 to 200 μm and the aperture ratio of the air holes is 3 to 50%.
It is preferable that the base film has a thickness of 30 μm or more.

  Further, the sound-absorbing film of the present invention uses a release paper instead of the base film, and laminates and joins the release paper and the breathable film with a certain interval through the adhesive layer, The air layer which connects the adhesion layer and the said vent hole may be provided between this air permeable film and this release paper.

The sound-absorbing film of the present invention is used by applying an adhesive or the like to a construction surface such as a window glass or a wall on the construction surface or the back surface of the substrate film and sticking it. When the surface is attached to a mirror-like flat construction surface such as a window glass, a film having self-adhesiveness may be used as the base film.
Also, for the construction surface where the adhesive of the adhesive layer can be directly adhered, the release paper is peeled off using a release paper instead of the base film without providing the base film. While providing a certain interval between the breathable film and the work surface, install so that there is an adhesive layer and an air layer communicating with the vent hole between the breathable film and the work surface. Also good.

The sound-absorbing film of the present invention has the structure described above, and the intruding sound propagated from the sound source side through the vent hole to the air layer provided in the sound-absorbing film is efficiently converted into the vibration of the film and absorbed, Since it is absorbed by the adhesive layer having a specific viscoelasticity provided in the sound absorbing film, the propagation of sound from the sound source side to the anti-sound source side is suppressed, and the sound absorbing effect is enhanced.
In addition, since a transparent or translucent film is used, the transparency is excellent, and even if it is used by being attached to a window glass or the like, the transparency and the lighting performance are not impaired.
Further, since it is transparent or translucent even when used on a wall or the like, there is no risk of impairing the aesthetics of the room.
Furthermore, the sound-absorbing film of the present invention can be produced as a long film and can be wound into a roll, so that it can be applied to various sizes of construction surfaces, so that it is easy to work. Excellent and excellent transport workability.

Hereinafter, although the sound-absorbing film of the present invention will be described in more detail, the present invention is not limited to this correspondence. FIG. 1 is an enlarged sectional view schematically showing a vertical section of a sound-absorbing film corresponding to one embodiment of the present invention, and FIG. 2 is a partially broken front view of the sound-absorbing film in FIG. 1 viewed from the breathable film side. .
The sound-absorbing film of the present invention includes a transparent or translucent air-permeable film 1 in which a plurality of air holes 4 penetrating from the front surface (sound source side) to the back surface are scattered, and a transparent or translucent base film 2. The air layer 5 is provided in the space formed between the pressure-sensitive adhesive layers 3 by being laminated and bonded in a linear or / and dot-like manner with a space of the air gap 4 therebetween. In other words, the adhesive layer 3 and the air layer 5 are provided between the breathable film 1 and the base film 2.
That is, the pressure-sensitive adhesive layer 3 serves not only as an adhesive for joining the breathable film 1 and the base film 2 but also as a spacer for keeping a certain distance between the two films, and the air layer 5. It is also a partition wall.

  In the implementation correspondence shown in FIG. 1 and FIG. 2, an example in which the adhesive layer 3 is provided in parallel with a certain interval in a stripe shape is shown. However, the adhesive layer 3 is composed of the breathable film 1 and the base film 2. You may make it dot regularly or randomly on the surface on the opposite side. However, in order to give the air permeable film 1 a function as an air hole, the adhesive layer 3 is formed at a position avoiding the opening of the air hole 4 formed in the air permeable film 1. When 1 and the base film 2 are bonded via the pressure-sensitive adhesive layer 3, it is preferable that the air layer 5 formed between the pressure-sensitive adhesive layers 3 and the air holes 4 are communicated with each other.

As the air-permeable film 1, for example, a transparent or translucent film such as an olefin-based, urethane-based, vinyl chloride-based, or polyethylene terephthalate-based material that has been physically perforated, or a nonwoven fabric is hot-pressed to increase transparency. Nonwoven fabric film having vent holes that have been made.
The thickness of the air permeable film 1 is preferably 10 to 200 μm, and if it is less than 10 μm, physical properties are insufficient when providing a vent or construction, and sound absorption performance is also inferior. While performance is inferior, it is not preferable in terms of workability as a sound-absorbing film.
The diameter of the vent hole 4 formed in the breathable film 1 is preferably 2 mm or less. If it exceeds 2 mm, it is not preferable in appearance, and the sound absorption is inferior.
It is preferable to adjust the aperture ratio to be in the range of 3 to 50% of the total area of the breathable film 1. Even if the opening rate of the vent hole 4 is less than 3% or more than 50%, the sound absorbing effect of the obtained sound absorbing film is hardly exhibited, which is not preferable.
On the other hand, the thickness of the base film 2 is preferably 30 μm or more, and if it is 30 μm or less, there is a possibility that the sound absorption and workability may be hindered. As a material, a film made of an olefin resin, a urethane resin, an acrylic resin, a polyethylene terephthalate resin, a vinyl chloride resin, or the like can be used.
Moreover, when using a release paper instead of a base film, what has a release layer on the surface generally used can be used.

As the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer 3, a pressure-sensitive adhesive made of acrylic resin, urethane resin, silicon resin, or the like is used, and among these, the loss tangent by linear viscoelasticity measurement at 23 ° C. is 0. It is preferable to use an adhesive that is 5 or more.
When the loss tangent of the pressure-sensitive adhesive is 0.50 or less as the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer 3, it is not preferable because the sound-absorbing effect of the sound-absorbing film is hardly exhibited.
Moreover, it is preferable that the area of the joined portion when the breathable film 1 and the base film 2 are joined via the adhesive layer 3 is 10 to 70% of the area of the film 1 or 2 in the adhesive layer 3. If it is less than%, it is difficult to keep the air-permeable film 1 and the base film 2 at regular intervals, and the sound absorbing performance is also deteriorated. If it exceeds 70%, the sound absorbing performance is deteriorated, which is not preferable.

The joining part for joining the breathable film 1 and the base film 2 with the adhesive 3 may be joined by point bonding (the adhesive layer 3 is formed in a dot shape) or in a linear form within the above range. You may adhere | attach (form the adhesion layer 3 in stripe form).
In the gap between the breathable film 1 and the base film 2, the portion not joined by the adhesive layer 3 becomes the air layer 4. At this time, the thicker the adhesive layer 4, the better the sound absorption in the low frequency region. Therefore, the thickness of the adhesive layer 4 (the thickness of the adhesive layer 4 in the direction perpendicular to the surface of the sound absorbing film) is 5 mm or less, preferably 0.5 to 3 mm. If the thickness of the adhesive layer 4 is less than 0.5 mm, a sufficient sound absorbing effect cannot be obtained. On the other hand, if the thickness is greater than 5 mm, it is difficult to handle as a film, and there is a problem that its use is limited.

The sound-absorbing film of the present invention is provided with an adhesive layer on the back surface or the work surface of the base film 2, and external noise such as a residence, automobile, railway vehicle, aircraft, etc. propagates to the inside through this adhesive layer. By affixing to a construction surface that needs to be suppressed, external noise is absorbed by the sound absorbing film, and the sound absorbing effect can be enhanced.
In the sound-absorbing film of the present invention, when the base film 2 has self-adhesiveness, it is preferable to laminate release paper instead of the adhesive on the back surface of the base film 2.
Moreover, the release paper is used instead of the base film 2, and the release paper is peeled off at the time of use, and the breathable film and the work surface are held at a constant interval via the adhesive layer. By sticking, it is also possible to use the work surface as an alternative to the base film.

  Further, at least one of the breathable film 1 and the base film 2 is formed of a material having a heat ray absorbing function such as a conductive metal oxide such as antimony-doped tin oxide (ATO) or tin-doped indium oxide (ITO). By kneading into the resin constituting the film or by applying it to the film surface, it is possible to obtain a sound-absorbing film that has heat insulation performance in addition to transparency and sound-absorbing property, and is pasted on a window glass or the like. Can be used effectively.

[Examples 1 to 14]
[Production of sound-absorbing film]
A hole with a diameter of 0.5 mm is uniformly perforated in a polypropylene film (made by Achilles Co., Ltd.) with a thickness of 25%, and an adhesive is applied to the surface of a 150 μm PET film. KP-2177 (Nippon Carbide, loss tangent = 0.3), KP-2361 (Nippon Carbide, loss tangent = 0.5), KP-2245 (Nippon Carbide, loss tangent = 1. 0), the pressure-sensitive adhesive was applied so that the bonding area was 50%, the film thickness of the pressure-sensitive adhesive was adjusted, and the respective polypropylene films were bonded together. Is shown in Table 1.

[Examples 15 to 19]
In addition, Table 2 shows the sound absorption rate of the sound absorbing film configured in the same manner as in Example 11 except that the bonding area is as shown in Table 2.

[Measurement of loss tangent]
About each sound-absorbing film obtained as mentioned above, loss tangent was measured by tension mode on the conditions of temperature 23 degreeC and measurement frequency 100-10000Hz using RSA-II made from Rheometrics. The obtained results are shown in Tables 1 and 2.
[Measurement of normal incidence sound absorption coefficient]
Each sound-absorbing film obtained as described above was measured according to the method for measuring the normal incident sound absorption coefficient of building materials according to the JIS A 1405 in-pipe method. The frequency region was measured at 100 to 4000 Hz. The normal incident sound absorption coefficient was measured for each sample, and the maximum incident sound absorption coefficient in the frequency region of 500 Hz or less was obtained. The obtained results are shown in Tables 1 and 2.

As can be seen from Table 1, among the sound-absorbing films of the present invention, when the aperture ratio is the same, the sound-absorbing film (Example 1) in which the film thickness of the breathable film is thinner than a certain thickness range, or the sound-absorbing film thicker than a certain thickness range. Both the films (Example 5) have a low sound absorption rate. In particular, when the thickness of the air-permeable film is large, the air-permeable film hardly vibrates due to sound, and the sound absorption due to the vibration of the film is low.
Further, when the thickness of the air permeable film is the same, the opening ratio of the air holes provided in the air permeable film is lower than a certain ratio (Example 6) or higher than the certain ratio (Example 8). ) Both have a low sound absorption coefficient, and particularly when the aperture ratio is low, it is not preferable because the sound does not easily pass through the air-permeable layer and the sound is reflected by the air-permeable film.

  Furthermore, even if the sound absorbing film has a loss tangent of the adhesive layer lower than a certain value (Example 9) or the sound absorbing film having a thickness of the adhesive layer thinner than a certain thickness (Example 10), sufficient sound absorbing is achieved. An effective sound-absorbing film cannot be obtained. In particular, when the thickness of the adhesive layer is thick (Example 14), a sufficient sound absorbing effect can be obtained, but there are difficulties in handling such as workability.

As can be seen from the comparison of Examples 1 to 8, when the tangent loss of the adhesive layer and the layer thickness are the same among the sound-absorbing films of the present invention, the thickness of the breathable film is in the range of about 10 to 200 mμ, By setting the aperture ratio of the ventilation holes of the breathable film to about 3 to 50%, a practically preferable sound absorbing film having a sound absorption rate of about 20% or more can be obtained.
Further, as can be seen from the comparison of Examples 9 to 13, when the film thickness of the air-permeable film and the aperture ratio of the air holes are made constant among the sound-absorbing films of the present invention, the loss tangent of the adhesive layer is about 0.5. Even when the layer thickness is 5 mm or less, a practically preferable sound-absorbing film having a sound absorption coefficient of about 20% or more can be obtained.

  Further, as is apparent from Table 2, even if the bonding area by the adhesive layer is too small (Example 15) or too large (Example 19), the sound absorption performance tends to be lowered, and the breathable film or substrate It can be seen that in the case of 10 to 70% of the entire area of the surface on the adhesive layer side of the material film (Examples 16, 17, and 18), excellent sound absorbing performance is exhibited.

It is an expanded sectional view perpendicular to the surface of the sound-absorbing film of the present invention. It is a front view which shows the state by which the sound-absorbing film of this invention was partially fractured seeing from the air permeable film side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Breathable film 2 Base film 3 Adhesive layer 4 Vent hole 5 Air layer

Claims (6)

A transparent or semi-transparent air permeable film in which a plurality of air holes penetrating from the front surface to the back surface are scattered and a transparent or semi-transparent substrate film are laminated and bonded at a predetermined interval via an adhesive layer. ,
The adhesive layer is provided in a linear or / and dot shape,
A sound-absorbing film, wherein an air layer that communicates the adhesive layer and the vent hole is provided between the two films.   The pressure-sensitive adhesive layer has a thickness of 5 mm or less, and a pressure-sensitive adhesive having a loss tangent by linear viscoelasticity measurement at 23 ° C of 0.50 or more is used as the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer. 2. The sound absorbing film according to 1.   In the said adhesion layer, the area of the junction part by the adhesion layer of the said air permeable film and the said base film is 10-70% of a film area, The any one of Claims 1-3 characterized by the above-mentioned. The sound absorbing film as described.   3. The sound-absorbing film according to claim 1, wherein the air-permeable film has a thickness of 10 to 200 μm and an opening ratio of the air holes of 3 to 50%.   The sound-absorbing film according to claim 1, wherein the base film has a thickness of 30 μm or more. A transparent or semi-transparent air permeable film in which a plurality of air holes penetrating from the front surface to the back surface are scattered, and a release paper are laminated and bonded at a predetermined interval via an adhesive layer.
The adhesive layer is provided in a linear or / and dot shape,
A sound-absorbing film, wherein an air layer is provided between the film and the release paper to communicate the pressure-sensitive adhesive layer and the vent hole.

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