TW201623004A - Flexible sound-absorption composite film - Google Patents

Abstract

A flexible sound-absorption composite film is provided. The flexible sound-absorption composite film includes a piezoelectrical surface layer, a sound-absorption layer and an adhesive layer. The adhesive layer is used to bond the piezoelectrical surface layer and the sound-absorption layer. The aforementioned piezoelectrical surface layer includes a polyfluoro resin, the sound-absorption layer includes a hydrocarbon resin having a hydroxylic group and a hollow micro particle, and the adhesive layer includes a fluoro compatibilizer and an isocyanato crosslinker. The hollow micro particle is equally dispersed in the sound-absorption layer. In the flexible sound-absorption composite film of the present invention, a total thickness of the piezoelectrical surface layer, the sound-absorption layer and the adhesive layer is 0.5 mm to 1 mm.

Description

Flexible sound absorbing composite film

The present invention relates to a composite film, and more particularly to a flexible sound absorbing composite film having both piezoelectric and sound absorbing effects.

Humans can receive various sounds through their ears and feel the changes in the external environment. However, when the human ear receives the excessive energy for a long time, the hearing ability of the ear will be reduced, and even permanent damage will be caused.

Sound absorbing materials or soundproofing materials are generally used to reduce the noise of the environment or to avoid its harm. The aforementioned soundproofing material continuously weakens the energy of the sound wave by rebounding energy to achieve the purpose of noise reduction. However, the conventional soundproofing material cannot dissipate the energy of the sound wave, so that the sound energy of the sound wave still affects others during the process of weakening.

The conventional sound absorbing material achieves the sound absorbing effect by the following two methods. The first method utilizes a metal aluminum plate and forms a (micro) hole structure on the aluminum plate, and the energy of the sound can be absorbed by the (micro) hole structure. The second method uses a thicker sound absorbing material (for example, fiberglass cotton or foam) to achieve noise reduction.

However, the aluminum sheet of the former is susceptible to environmental influences (eg, chemical vapor corrosion) and reduces its service life. Secondly, the aluminum plate is not flexible, and its applicable environment and application range are limited. As for the latter, the sound absorbing effect of the thicker sound absorbing material is related to the thickness, and when the thickness is reduced, the sound absorbing effect is also greatly reduced.

In view of the above, it is not necessary to provide a flexible sound absorbing composite film to improve the defects of the conventional flexible sound absorbing composite film.

One aspect of the present invention provides a flexible sound absorbing composite film which is bonded to a piezoelectric surface layer and a sound absorbing layer by a bonding layer to provide piezoelectric and sound absorbing effects.

According to an aspect of the present invention, a flexible sound absorbing composite film is proposed. The flexible sound absorbing composite film comprises a piezoelectric surface layer and a sound absorbing layer provided on a surface of the piezoelectric surface layer. The piezoelectric surface layer contains a polyfluoro resin. The sound absorbing layer contains a polyhydrocarbon resin having a hydroxyl group and a plurality of hollow fine particles uniformly dispersed therein. The flexible sound absorbing composite film is characterized in that a bonding layer is provided between the piezoelectric surface layer and the sound absorbing layer.

The aforementioned bonding layer contains a fluorine-based compatibilizer and an isocyanate-based bridging agent in a weight ratio of 1:0.03 to 1:0.1. The hollow microparticles are used in an amount of from 5 to 10% by weight based on 100% by weight of the polyhydrocarbon-based resin having a hydroxyl group. The total thickness of the piezoelectric surface layer, the sound absorbing layer and the adhesive layer is from 0.5 mm to 1 mm.

According to an embodiment of the present invention, the polyfluoro resin is a polyvinylidene fluoride of a β phase.

According to another embodiment of the present invention, the polyhydroxycarbon resin having a hydroxyl group has a structure represented by the following formula (I):

In formula (I), the ratio of a to b is from 75:22 to 82:18, and the ratio of a to d is from 75:3 to 82:1.

According to still another embodiment of the present invention, the aforementioned hydrocarbon-having polyhydrocarbon resin having a structure represented by the formula (I) has a molecular weight of 105,000 to 112,000.

According to still another embodiment of the present invention, the hollow microparticles include a plurality of first sub-hollow particles and a plurality of second sub-hollow particles, the first sub-hollow particles having a particle diameter of 5 μm to 90 μm, and the second The particle diameter of the sub hollow particles is from 10 μm to 190 μm.

According to still another embodiment of the present invention, the first sub-hollow fine particles have an average particle diameter (D90) of 46 μm, and the second sub-hollow fine particles have an average particle diameter (D90) of 76 μm.

According to still another embodiment of the present invention, the adhesive layer comprises polyvinyl butyral, and the weight ratio of polyvinyl butyral to the fluorine-based compatibilizer is 1:5.

According to still another embodiment of the present invention, the flexible sound absorbing complex The film further comprises a protective layer, wherein the protective layer is disposed on the sound absorbing layer, and the sound absorbing layer is disposed between the protective layer and the adhesive layer.

According to still another embodiment of the present invention, the flexible sound absorbing complex The acoustic wave frequency absorbed by the film is from 100 Hz to 5000 Hz.

The flexible sound absorbing composite film of the invention is applied by using a viscous sound absorbing composite film The junction layer is combined with the piezoelectric surface layer and the sound absorbing layer, and the sound wave energy is absorbed by the hollow particles of the sound absorbing layer, so that the obtained flexible sound absorbing composite film has both piezoelectric characteristics and sound absorbing characteristics, thereby achieving the effect of noise reduction.

100‧‧‧Flexible sound absorbing composite film

100a‧‧ Direction

110‧‧‧ Piezoelectric surface

120‧‧ ‧ sound absorbing layer

120a‧‧‧ hollow particles

130‧‧‧bonded layer

200‧‧‧Flexible sound absorbing composite film

200a‧‧ Direction

210‧‧‧ Piezoelectric surface

220‧‧‧ Sound absorbing layer

220a‧‧‧ hollow particles

230‧‧‧bonded layer

240‧‧‧protection layer

1 is a cross-sectional view showing a flexible sound absorbing composite film in accordance with an embodiment of the present invention.

2 is a cross-sectional view showing a flexible sound absorbing composite film in accordance with another embodiment of the present invention.

The making and using of the embodiments of the invention are discussed in detail below. However, it will be appreciated that the embodiments provide many applicable inventive concepts that can be implemented in a wide variety of specific content. The specific embodiments discussed are illustrative only and are not intended to limit the scope of the invention.

The "sound absorbing" material according to the present invention means that the material has the effect of absorbing sound energy, and is different from the "sound insulation" material that rebounds the sound energy.

Please refer to FIG. 1 , which is flexible according to an embodiment of the present invention. A cross-sectional view of a sound absorbing composite film. In this embodiment, the flexible sound absorbing composite film 100 includes a piezoelectric surface layer 110 and a sound absorbing layer 120 disposed on a surface of the piezoelectric surface layer 110. The flexible sound absorbing composite film 100 is characterized in that a bonding layer 130 is provided between the piezoelectric surface layer 110 and the sound absorbing layer 120.

The piezoelectric surface layer 110 includes a polyfluoro resin, and the polyfluorinated tree The lipid is, for example, a β-phase polyvinylidene fluoride, and the β-phase polyvinylidene fluoride is a piezoelectric material having piezoelectric characteristics.

The aforementioned piezoelectric characteristics mean that the piezoelectric material is subjected to the action of sound waves. When the energy of the sound wave is absorbed by the piezoelectric material, the molecular chain of the piezoelectric material is oscillated, thereby generating electrical energy. In the flexible sound absorbing composite film of the present invention, the weak electric energy generated by the piezoelectric material due to the sound wave is dissipated in the piezoelectric surface layer, and the effect of absorbing the sound wave is achieved.

When preparing the above-mentioned β phase polyvinylidene fluoride, the α phase is first gathered. The vinylidene fluoride is extended in the forward direction, and the polyvinylidene fluoride of the α phase is converted into the polyvinylidene fluoride of the β phase. As the stretching ratio increases, the content of the β-phase polyvinylidene fluoride also increases. It should be specially noted that when the α-phase polyvinylidene fluoride is formed by extrusion from a die, the direction of extension of the "progressive extension" is the direction in which the film is extruded; when the α phase of polyvinylidene fluoride is used When the solution is applied to the solvent casting, since the arrangement of the molecular chains in the film is not directional, any direction of extension may be the direction in which the "longitudinal extension" extends.

When the piezoelectric surface layer 110 contains a trace amount of β phase polyvinylidene fluoride At this time, the piezoelectric surface layer 110 can absorb the energy of the sound wave to generate electric energy. In an embodiment, in order to obtain a significant effect of absorbing sound energy, based on polyposition When the content of the vinyl fluoride is 100%, the content of the polyvinylidene fluoride of the β phase is preferably not less than 60%.

In order to maintain the piezoelectric properties of the aforementioned β-phase polyvinylidene fluoride, The flexible sound absorbing composite film of the present invention preferably has a use temperature of not more than 80 ° C, and more preferably not more than 60 ° C.

The sound absorbing layer 120 includes a polyhydrocarbon tree having a hydroxyl group. The fat and the hollow fine particles 120a which are evenly dispersed in the sound absorbing layer 120.

The polyhydrocarbon resin having a hydroxyl group may have a structure represented by the following formula (I):

In formula (I), the ratio of a to b is from 75:22 to 82:18, and the ratio of a to d is from 75:3 to 82:1.

In one embodiment, the polyhydrocarbon resin having a hydroxyl group having a structure represented by the formula (I) has a molecular weight of 105,000 to 112,000.

In an embodiment, the material of the hollow particles 120a may include glass and aerogel. The aerogel described above preferably does not react with the polyhydrocarbon resin having a hydroxyl group and can be uniformly dispersed in the sound absorbing layer 120a, and the aerogel is more preferably a ceria-based aerogel.

The hollow fine particles 120a may include a plurality of first sub-hollow particles and a plurality of second sub-hollow particles. Preferably, the particle diameter of the first sub-hollow particles is different from the particle diameter of the second sub-hollow particles.

When the particle size of the first sub-hollow particle is different from the second sub-hollow micro In the particle size of the particles, the first sub-hollow particles and the second sub-hollow particles may be dispersed in the sound absorbing layer 120 in accordance with the "closest packing". In detail, the "closest packing" method means that when the hollow particles having a large particle diameter are closely arranged, due to the influence of the large particle diameter, a gap is easily formed between the hollow particles, and the hollow particles having a smaller particle diameter can be made. The filling accumulates in this gap, which in turn makes the accumulation of the daughter hollow particles more compact.

In one embodiment, the first sub-hollow particles have a particle size of 5 μm. Up to 90 μm, and the particle diameter of the second sub-hollow fine particles is from 10 μm to 190 μm. More specifically, the average particle diameter (D90) of the first sub-hollow fine particles was 46 μm, and the average particle diameter (D90) of the second sub-hollow fine particles was 76 μm.

In the sound absorbing layer 120, a polyhydrocarbon resin having a hydroxyl group may be used. Resound the energy of the sound waves and achieve the function of "sound insulation". Furthermore, since the hollow fine particles 120a have a hollow structure, and the hollow structure can block the transmission of the sound waves, and the energy of the sound waves is dissipated in the sound absorbing layer 120, the hollow fine particles 120a have the function of "absorbing sound".

The sound absorbing layer 120 of the present invention is combined with a "sound insulation" function. The polyhydrocarbon resin having a hydroxyl group and the hollow fine particles 120a having a "sound absorption" function, and the hollow fine particles are uniformly dispersed in the sound absorbing layer 120 (that is, evenly dispersed in a polyhydrocarbon resin having a hydroxyl group), so that the sound absorbing of the present invention Layer 120 is effective in absorbing the energy of the sound waves.

The amount of the polyhydrocarbon-based resin having a hydroxyl group is The hollow fine particles 120a are used in an amount of 5 to 10% by weight based on 100 parts by weight.

If the hollow particles 120a are used in an amount less than 5 weight percent When the amount of the hollow fine particles 120a used is too small, the obtained sound absorbing layer 120 cannot effectively "sound", and the function of noise reduction cannot be achieved. Secondly, due to the influence of the hollow structure of the hollow fine particles 120a, the hollow fine particles 120a have a light weight. Therefore, if the hollow fine particles 120a are used in an amount of more than 10% by weight, the excessive hollow fine particles 120a lowers the mechanical mechanism of the sound absorbing film 120. The properties are more brittle, and even the polyhydrocarbon resin having a hydroxyl group cannot form a continuous body, and it is difficult to form a film, and thus the sound absorbing layer 120 of the present invention cannot be obtained.

It should be specially stated that if the amount of the hollow particles used is small At 5 weight percent, although the sound absorbing layer cannot effectively "sound", the noise reduction effect can be achieved by increasing the thickness of the sound absorbing layer. However, increasing the thickness of the sound absorbing layer increases the thickness of the resulting flexible sound absorbing composite film, which affects its application range.

With continued reference to FIG. 1, the bonding layer 130 includes a fluorine-based compatibilizer and Isocyanate bridging agent.

The above-mentioned fluorine-based compatibilizer means an official having a hydroxyl group and a fluorine atom. A long carbon chain compound based on energy. Wherein, the hydroxyl group of the fluorine-based compatibilizing agent can react with the hydroxyl group of the polyhydrocarbon-based resin having a hydroxyl group of the sound absorbing layer 120; and the fluorine atom can react with the fluorine atom of the polyfluoro-based resin of the piezoelectric surface layer 110. .

Secondly, the isocyanate bridging agent can enhance the sound absorbing layer 120. The force of the polyhydroxycarbon resin having a hydroxyl group and a fluorine-based compatibilizer.

Therefore, the bonding agent 130 of the present invention can effectively bond the piezoelectric meter The layer 110 and the sound absorbing layer 120 have the characteristics of piezoelectric characteristics and "sound absorption" of the flexible sound absorbing composite film of the present invention, thereby achieving the effect of noise reduction.

The specific example of the fluorine-based compatibilizer may be a Daikin apex chemical unit. The goods manufactured by the company, and its model number is GK-510, GK-570 or GK-580.

The specific example of the aforementioned isocyanate bridging agent may be made of Taichang resin. An isocyanate bridging agent is produced, and its isocyanate group content is from 22.5% to 24.5%.

In one embodiment, a fluorine-based compatibilizer and an isocyanate bridging agent When the weight ratio is 1:0.03 to 1:0.1, the obtained adhesive layer 130 has an interface bonding strength of 1.7 kg/in to 2.2 kg/in. Preferably, the weight ratio of the fluorine-based compatibilizer and the isocyanate-based bridging agent may be 1:0.05.

If the weight ratio of fluorine-based compatibilizer and isocyanate bridging agent is not In the above range, too little isocyanate bridging agent reduces the bonding effect of the bonding layer 130 and the sound absorbing layer 120; and too few fluorine-based compatibilizers reduce the bonding effect of the bonding layer 130 and the piezoelectric surface layer 110.

In another embodiment, the bonding layer 130 can be selectively added The weight ratio of polyvinyl butyral, polyvinyl butyral to fluorine-based compatibilizer is 1:5, and the resulting adhesive layer 130 has an interfacial adhesion strength of from 1.63 kg/in to 2.37 kg/in. Specifically, when the adhesive layer 130 comprises polyvinyl butyral, the method for manufacturing the adhesive layer 130 is, for example, first mixing polyvinyl butyral with a fluorine-based compatibilizer according to the above ratio to form a mixture, and then The mixture is mixed with an isocyanate bridging agent.

Please continue to refer to Figure 1, in a specific example, when the sound wave is in the direction When the 100a is transmitted, the piezoelectric surface layer 110 of the flexible sound absorbing composite film 100 is directed toward the source of the sound wave. When the acoustic wave contacts the piezoelectric surface layer 110, the energy of the acoustic wave portion oscillates the piezoelectric material of the piezoelectric surface layer 110 to generate electrical energy, and the generated electrical energy is converted into thermal energy and dissipated in the sound absorbing layer 120.

The remaining sonic energy will continue to be transmitted to the sound absorbing layer 120. When the energy of the sound wave is transmitted to the sound absorbing layer 120, the polyhydrocarbon resin having a hydroxyl group in the sound absorbing layer 120 bounces part of the sound energy, but the hollow particle 120a absorbs the energy of the sound wave (including the energy of the sound wave transmission and the aforementioned The energy of the rebound). Therefore, when the remaining energy of the aforementioned sound wave is transmitted to the sound absorbing layer 120, the sound absorbing layer 120 absorbs the energy of the sound wave to achieve the effect of noise reduction.

Please refer to FIG. 2, which illustrates another embodiment in accordance with the present invention. A cross-sectional view of a flexible sound absorbing composite film. In this embodiment, the structure of the flexible sound absorbing composite film 200 is substantially the same as that of the flexible sound absorbing composite film 100, and the difference is that the flexible sound absorbing composite film 200 further includes the protective layer 240. The protective layer 240 is disposed on the sound absorbing layer 220, and the sound absorbing layer 220 is disposed between the protective layer 240 and the bonding layer 230.

In an embodiment, the protective layer 240 may be agglomerated with hydroxyl groups. It is made of a hydrocarbon-based resin in which the polyhydrocarbon-based resin having a hydroxyl group of the protective layer 240 may be the same as or different from the polyhydrocarbon-based resin having a hydroxyl group used in the sound absorbing layer 220. Preferably, when the material used for the protective layer 240 is the same as the polyhydrocarbon resin having a hydroxyl group of the sound absorbing layer 220, the protective layer 240 and the sound absorbing layer 220 have a good bonding effect without using a binder. In addition, due to The polyhydrocarbon resin having a hydroxyl group has the effect of "sound insulation", so the protective layer 240 can improve the noise reduction effect of the flexible sound absorbing composite film.

Similarly, in a specific example, when the sound wave is transmitted in the direction 200a When delivered, the piezoelectric skin 210 of the flexible sound absorbing composite film 200 is oriented toward the source of the sound waves. When the sound wave contacts the flexible sound absorbing composite film 200, part of the sound wave energy oscillates the piezoelectric material of the piezoelectric surface layer 210, and the remaining energy is transmitted to the sound absorbing layer 220.

The foregoing remaining energy will be hydroxylated in the sound absorbing layer 220. The polyhydrocarbon resin and the polyhydrocarbon resin having a hydroxyl group in the protective layer 240 bounce, but the hollow microparticles 220a can absorb the energy of the rebounded sound wave and the energy transmitted to the sound absorbing layer 220, thereby achieving the effect of "sound absorption", thereby being effective. Noise reduction.

In an application example, the flexible sound absorbing composite film of the present invention can be The absorbed acoustic wave frequency is from 100 Hz to 5000 Hz, and the total thickness of the piezoelectric surface layer, the sound absorbing layer and the adhesive layer is from 0.5 mm to 1 mm.

If the total thickness is less than 0.5 mm, the flexible sound absorbing complex The film is not easy to prepare, and the thickness is too thin to reduce its noise reduction effect. If the total thickness is greater than 1 mm, although the larger thickness can increase the noise reduction effect, the excessively thick sound absorbing film also reduces the application field.

Secondly, the flexible sound absorbing composite film of the present invention is utilized. The polymer material (polyfluoro resin and polyhydrocarbon resin) is obtained, so that the flexible sound absorbing composite film of the present invention has flexibility and can be flexed to match the occasion or device used, thereby expanding its application. The convenience of the field and use.

Furthermore, the aforementioned polymeric materials are resistant to chemicals (including Corrosion of chemical vapor), so that the flexible sound absorbing composite film can be used in a chemical environment for a long time.

The following examples are used to illustrate the application of the present invention, and It is not intended to limit the invention, and various modifications and refinements can be made without departing from the spirit and scope of the invention.

Preparation of bonding layer

The adhesive layers of Specific Examples 1 to 3 and Comparative Specific Example 1 and Comparative Specific Example 2 were prepared according to the first table.

Specific example 1

First, weigh 100% by weight of a fluorine-based compatibilizer (manufactured by Daikin Shoutsu Chemical Co., Ltd. and its model number is GK-570) and 3 wt% of isocyanate bridging agent (made by Taichang Resin) And mix the two.

Then, the mixed material was heated to 60 ° C to carry out a synthesis reaction, and the adhesive layer of Specific Example 1 was obtained. The obtained adhesive layer was evaluated by the following "interfacial adhesion strength" evaluation method, and the obtained result is shown in the first table.

Specific Example 2 and Specific Example 3, Comparative Specific Example 1 and Comparative Specific Example 2

In the specific example 2, the specific example 3, the comparative specific example 1 and the comparative specific example 2, the preparation method similar to the manufacturing method of the adhesive layer of the specific example 1 is used, except the specific example 2 and the specific example 3 and the comparative specific example 1. And the specific example 2 is used to change the amount of isocyanate bridging agent used, of which specific examples 2 The isocyanate-based bridging agent is not used, and the amount of use and evaluation results are shown in Table 1, and will not be further described herein.

Preparation of flexible sound absorbing composite film

First, polyvinylidene fluoride is melted and subjected to a film forming step to obtain a piezoelectric film having an α phase of polyvinylidene fluoride. Then, the piezoelectric film is subjected to an extension step, and a piezoelectric surface layer having a β phase of polyvinylidene fluoride can be obtained, wherein the temperature of the stretching step is 100 ° C, the stretching ratio is 3.5 times, and the β phase is polyvinylidene fluoride. The ethylene content is from 68.7% to 70.3%.

Next, the flexible sound absorbing composite films of Examples 1 to 7 and Comparative Example 1 and Synthesis Example 2 were prepared according to the second table.

Example 1

First, 100% by weight of polyvinyl butyral and 5 weight percent of hollow glass spheres (commercially available from Potters, trade name: Q-cel, and an average diameter of 46 μm) were mixed to make hollow glass spheres. It is evenly dispersed in polyvinyl butyral.

The hollow glass ball can be stirred at a low rotation speed by a stirring device made of a polymer material to avoid breakage of the hollow glass ball caused by intense agitation.

Then, a film forming step of the mixture of polyvinyl butyral and hollow glass spheres is carried out to obtain a sound absorbing layer.

Then, the flexible sound absorbing composite film of the first embodiment can be obtained by using the bonding layer of the above-mentioned Synthesis Example 2 in combination with the sound absorbing layer and the piezoelectric surface layer, wherein the flexible sound absorbing composite film of the first embodiment has a thickness of 1 metric. PCT. Made by The flexible sound absorbing composite film was evaluated by the following evaluation method of "sound absorption coefficient", and the obtained results are shown in Table 2.

Example 2 to Example 7 and Comparative Example 1 and Comparative Example 2

Examples 2 to 7 and Comparative Example 1 and Comparative Example 2 were prepared in the same manner as in the method of producing the adhesive layer of Example 1, except that Examples 2 to 7 and Comparative Example 1 and Comparative Example were used. 2 is used to change the amount of hollow glass spheres used and the average particle diameter thereof, and the amount, conditions, and evaluation results are shown in Table 2, and will not be further described herein. Among them, Example 7 is a method of simultaneously mixing two hollow glass spheres having different average particle diameters.

Evaluation method 1. Interface strength

The interfacial adhesion strength of the adhesive layer of the present invention was measured by a tensile tester according to the Japanese Industrial Standards (JIS) L1089 method.

2. Sound absorption coefficient

The sound absorption coefficient of the flexible sound absorbing composite film of the present invention is measured by Impedance Tube Solutions and according to the standard set by E 1050 of American Society for Testing and Materials (ASTM). Measurement.

Next, the Noise Reduction Coefficient (NRC) contained in the second table calculates the summed average of the sound absorption coefficients of the flexible sound absorbing composite film measured at 200 Hz to 2000 Hz.

It can be seen from the results of Tables 1 and 2 that when the fluorine layer of the bonding layer is compatible When the weight ratio of the agent to the isocyanate bridging agent is from 1:0.03 to 1:0.1, the resulting adhesive layer has an interfacial adhesion strength of from 1.7 kg/in to 2.2 kg/in. Therefore, the adhesive layer of the present invention can surely bond the piezoelectric surface layer and the sound absorbing layer, and the flexible sound absorbing composite film has both "piezoelectric characteristics" and "sound absorption characteristics", thereby improving the noise reduction effect of the flexible sound absorbing composite film. .

Second, it can be seen from the above embodiments of the present invention that the present invention When the hollow particles in the sound absorbing layer are composed of the first sub-hollow particles and the second sub-hollow particles having different particle diameters, the obtained flexible sound absorbing composite film has a higher noise reduction coefficient, so that it is better. "Sound absorption" effect.

Furthermore, as the amount of hollow particles added increases, flexibility The noise reduction factor of the sound absorbing composite film is also increased. Accordingly, the hollow fine particles of the sound absorbing layer of the present invention can enhance the "sound absorbing" effect of the flexible sound absorbing composite film.

In addition, since the high frequency sound waves have a large oscillation frequency, The piezoelectric characteristics of the piezoelectric material of the piezoelectric surface layer are more obvious. Therefore, for high-frequency sound waves, the piezoelectric surface layer of the flexible sound absorbing composite film of the present invention can effectively absorb its energy, and further improve the noise reduction effect of the flexible sound absorbing composite film.

The present invention has been disclosed in the above embodiments, and is not intended to limit the present invention. Any one of ordinary skill in the art to which the present invention pertains can make various changes without departing from the spirit and scope of the invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

100‧‧‧Flexible sound absorbing composite film

100a‧‧ Direction

110‧‧‧ Piezoelectric surface

120‧‧ ‧ sound absorbing layer

120a‧‧‧ hollow particles

130‧‧‧bonded layer

Claims (9)

A flexible sound absorbing composite film comprising a piezoelectric surface layer and a sound absorbing layer disposed on a surface of the piezoelectric surface layer, the piezoelectric surface layer comprising a polyfluoro resin, the sound absorbing layer comprising a polyhydrocarbon having a hydroxyl group a resin and a plurality of hollow fine particles dispersed therein, wherein a bonding layer is disposed between the piezoelectric surface layer and the sound absorbing layer, wherein the bonding layer comprises a fluorine system having a weight ratio of 1:0.03 to 1:0.1. The compatibilizing agent and the isocyanate bridging agent are used in an amount of 100% by weight based on the hydroxyl group-containing polyhydrocarbon resin, and the hollow particles are used in an amount of 5 to 10% by weight, and the piezoelectric skin layer The sound absorbing layer and the bonding layer have a total thickness of 0.5 mm to 1 mm. The flexible sound absorbing composite film according to claim 1, wherein the polyfluoro resin is a polyvinylidene fluoride of a β phase. The flexible sound absorbing composite film according to claim 1, wherein the polyhydroxycarbon resin having a hydroxyl group has a structure represented by the following formula (I): In formula (I), the ratio of a to b is from 75:22 to 82:18, and the ratio of a to d is from 75:3 to 82:1. The flexible sound absorbing composite film according to claim 3, wherein the hydroxyl group-having polyhydrocarbon resin having a structure represented by the formula (I) has a molecular weight of 105,000 to 112,000. The flexible sound absorbing composite film according to claim 1, wherein the hollow particles comprise a plurality of first sub-hollow particles and a plurality of second sub-hollow particles, and the particle diameters of the first sub-hollow particles are 5 μm to 90 μm, and the second sub-hollow particles have a particle diameter of 10 μm to 190 μm. The flexible sound absorbing composite film according to claim 5, wherein the first sub-hollow particles have an average particle diameter (D90) of 46 μm, and the average particle diameter of the second sub-hollow particles (D90) It is 76 μm. The flexible sound absorbing composite film according to claim 1, wherein the adhesive layer comprises polyvinyl butyral, and the weight ratio of the polyvinyl butyral to the fluorine-based compatibilizer is 1: 5. The flexible sound absorbing composite film according to claim 1, further comprising a protective layer, wherein the protective layer is disposed on the sound absorbing layer, and the sound absorbing layer is disposed between the protective layer and the adhesive layer. The flexible sound absorbing composite film according to claim 1, wherein the flexible sound absorbing composite film absorbs a sound wave frequency of 100 Hz to 5000 Hz.