JP4991115B2 - Incombustible sound absorbing foam - Google Patents

Description

  The present invention relates to a non-combustible sound absorbing foam that can be applied to a wide range of uses such as a soundproof cover applied to piping in a building, a lining for home appliances and vehicles, and an interior material for a house. Specifically, the present invention relates to a non-combustible sound absorbing foam that is thin and has excellent sound absorbing properties, sound insulating properties, and non-combustible properties.

  Conventionally, as a sound-absorbing foam, a foam-molded article made of a polymer such as polyurethane, polyethylene, or polyvinyl chloride is known. In these sound absorbing foams, when a sound hits the foam, the air vibration is transmitted to the air in the bubble portion inside the foam. Then, viscous friction of air is generated in the bubble portion, a part of sound energy is converted into heat energy, and a sound absorption effect is guided by a sound absorption mechanism in which sound absorption is generated.

  However, these conventional sound-absorbing foams have a technical problem that they have almost no effect on sound having a frequency lower than 2000 Hz.

  For example, in order to completely absorb sound with a frequency below 2000 Hz, it is sufficient to increase the thickness of the sound absorbing foam, but in the case of 10 KHz sound, the sound is completely absorbed at a thickness of 3.4 cm. On the other hand, in the case of 100 Hz, a thickness of 3.4 m is required, and in reality, it cannot be implemented due to problems such as space and cost.

  Therefore, by changing the density, foaming ratio, and cell ratio of the sound absorbing foam to increase the sound absorbing level of the foam and improving the performance, that is, by raising the bottom, the sound absorbing property can be obtained with respect to the sound having a frequency below 2000 Hz. Although attempts have been made to achieve this, only an improvement of about 20 to 30% has been made, and sufficient sound absorbing properties could not be obtained.

  As a result of intensive studies for solving such technical problems, the present applicant has proposed a sound-absorbing foam that is thin and has a sufficient sound-absorbing property for sound having a frequency lower than 2000 Hz.

This sound-absorbing foam is an organic system comprising one or more selected from a compound having a benzothiazyl group, a compound having a benzotriazole group, and a compound having a diphenylacrylate group in the base polymer constituting the foam. It is characterized by containing a high attenuation agent (see Patent Document 1).
Japanese Patent No. 3318593

  The thin and high performance sound absorbing foam proposed by the present applicant has been widely applied to automobiles, interior materials, building materials, home appliances, etc. But there was a new technical challenge. The technical issue is “incombustibility”.

  Interior restrictions are imposed by the Building Standards Act on highly public special buildings such as houses, theaters, gathering venues, hospitals, and hotels. The interior restriction refers to the use of non-combustible materials or heat-insulating materials certified as semi-incombustible materials, or non-combustible materials with legal permission for the surface of heat-insulating materials when constructing special public buildings. It is a restriction that it must be covered with materials (Building Standards Law: Article 35-2, Construction Order, Article 128-3, Paragraph 2 to Article 129).

  Such legal restrictions are also imposed on the interior of ships and aircraft. In addition, not only special buildings, but also interiors of ordinary houses and buildings, and interiors of vehicles such as automobiles, there is a large demand for incombustibility or flame retardance from both users and manufacturers.

  The present applicant has studied the problem of “non-combustibility” that is legally regulated or required as described above, and as a result, has completed the present invention.

  That is, an object of the present invention is to propose a non-combustible sound absorbing foam that is thin, has high performance, and has excellent non-combustibility.

In order to achieve the above object, the present invention provides a sound absorbing foam in which a base polymer constituting the foam includes a compound having a benzothiazyl group, a compound having a benzotriazole group, a compound having a diphenyl acrylate group, and a benzophenone group. Contains one or more organic high-attenuating agents selected from the compounds possessed, and a black paint having a viscoelastic polymer as a coating film component is applied to one surface of the foam The gist of the non-combustible sound absorbing foam is characterized by providing a skin layer made of a metal layer .

  The category of “non-combustibility” in the present invention includes “incombustibility” in addition to “non-combustibility” defined in the Building Standard Law and the like.

As described above, the present invention is a sound-absorbing foam having a benzothiazyl group compound, a benzotriazole group compound, a diphenyl acrylate group compound, and a benzophenone group compound in the base polymer constituting the foam. From a metal layer that contains one or more organic high-attenuating agents selected from among them, and a black paint having a viscoelastic polymer as a coating film component is applied to one surface of the foam By providing such a skin layer , it is thin, has excellent sound absorbing properties and sound insulating properties, particularly excellent sound absorbing properties in a low frequency range of 2000 Hz or less, and has sufficient nonflammability.

  Hereinafter, the noncombustible sound absorbing foam of the present invention will be described in more detail. In the noncombustible sound absorbing foam of the present invention, the foam is, for example, polyurethane, polyvinyl alcohol, polyvinyl chloride, chlorinated polyethylene, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polymethyl methacrylate, polystyrene, styrene-butadiene-acrylonitrile. One or a mixture of two or more polymers selected from copolymers, polyvinyl formal, epoxy, phenol, urea, and silicon, or acrylic rubber (ACR), acrylonitrile-butadiene rubber (NBR), styrene-butadiene One or a mixture of two or more rubber polymers selected from rubber (SBR), butadiene rubber (BR), natural rubber (NR), isoprene rubber (IR), and chloroprene rubber (CR) as a base polymer It can be formed.

  Foam absorbs an inert gas into the polymer by using the above-mentioned base polymer with a conventionally known bubble generating means, that is, a bubble generating means using a pyrolytic foaming agent, a bubble generating means using a volatile solvent, or a high pressure. It is obtained by foam molding using a bubble generating means for foaming at normal pressure.

  In selecting the base polymer that constitutes the foam, the application and use form of the foam, handleability, moldability, availability, temperature performance (heat resistance and cold resistance), weather resistance, price, etc. It is desirable to consider.

  In addition, although it is arbitrary as a foaming ratio of the base polymer which comprises foam | foam, Preferably it is 5-50 times, More preferably, it is 10-30 times. This is because, when the expansion ratio is less than 5 times, sufficient sound absorption cannot be obtained, and when the expansion ratio exceeds 50 times, the mechanical strength is lowered. Further, the number of pores and the bulk density of the foam also increase the sound absorption as the numerical value increases. Therefore, when the foam is molded, it may be appropriately determined according to the expansion ratio.

  The foam cell structure is, in principle, an open cell structure. However, depending on the application location of the foam and the required sound absorption and mechanical strength, it may be a closed cell type.

  The base polymer constituting the foam contains an organic high attenuation agent. An organic high damping agent dramatically increases the sound absorption, particularly in the low frequency range of 2000 Hz or less, by greatly increasing the amount of dipole moment of the base polymer constituting the foam. It is an additive that can be used.

  Examples of organic high-attenuating agents having such effects include N, N-dicyclohexylbenzothiazyl-2-sulfenamide (DCHBSA), 2-mercaptobenzothiazole (MBT), and dibenzothiazyl sulfide (MBTS). N-cyclohexylbenzothiazyl-2-sulfenamide (CBS), N-tert-butylbenzothiazyl-2-sulfenamide (BBS), N-oxydiethylenebenzothiazyl-2-sulfenamide (OBS) ), A compound containing a benzothiazyl group such as N, N-diisopropylbenzothiazyl-2-sulfenamide (DPBS), benzotriazole having an azole group bonded to the benzene ring as a mother nucleus, and a phenyl group bonded thereto 2 -{2'-hydroxy-3 '-(3 ", 4", 5 ", 6" Torahydrophthalimidemethyl) -5′-methylphenyl} -benzotriazole (2HPMB), 2- {2′-hydroxy-5′-methylphenyl} -benzotriazole (2HMPB), 2- {2′-hydroxy- 3'-t-butyl-5'-methylphenyl} -5-chlorobenzotriazole (2HBMPCB), 2- {2'-hydroxy-3 ', 5'-di-t-butylphenyl} -5-chlorobenzotriazole A compound having a benzotriazole group such as (2HDBPCB), a compound having a diphenyl acrylate group such as ethyl-2-cyano-3,3-diphenyl acrylate, or 2-hydroxy-4-methoxybenzophenone (HMBP), 2-hydroxy- 4-methoxybenzophenone-5-sulfonica It can include one or more selected from among compounds having a benzophenone group such de (HMBPS).

  The content of the organic high attenuation agent is preferably 1 to 100 parts by weight with respect to 100 parts by weight of the base polymer constituting the foam. For example, when the content of the organic high attenuation agent is less than 1 part by weight, a sufficient effect due to the addition of the organic high attenuation agent that increases the amount of dipole moment cannot be obtained. This is because when the content of the damping agent exceeds 100 parts by weight, the base polymer constituting the foam and the organic high damping agent may not be sufficiently compatible.

  In determining the type of organic high attenuation agent to be included in the base polymer constituting the foam, considering the compatibility of the organic high attenuation agent and the base polymer constituting the foam, that is, the SP value, You should select the ones with similar values.

  The amount of dipole moment varies depending on the type of base polymer and organic high-damping agent constituting the foam. Even if the same organic high attenuation agent is used, the amount of dipole moment varies depending on the temperature at which sound energy is transmitted. The amount of dipole moment varies depending on the energy level of the sound. For this reason, considering the temperature at the time of application of the foam and the magnitude of sound energy, the base polymer and organic high damping agent that make up the foam are selected so that the maximum amount of dipole moment is obtained at that time. It is desirable to use it.

  It should be noted that additives such as antioxidants, reinforcing agents / reinforcing agents, antistatic agents, flame retardants, lubricants, foaming agents, and coloring agents are appropriately blended in the foam as long as the sound absorption of the foam is not impaired. Can do.

A skin layer composed of a metal layer coated with a black paint having a viscoelastic polymer as a coating film component is provided on one surface of the foam. As a metal layer, what consists of metals, such as aluminum, iron, stainless steel, copper, is desirable. Specifically, it can be used in the form of a metal foil formed by stretching the metal and having a thickness of 5 to 30 microns. By providing this metal layer on one surface of the foam, it is possible to impart nonflammability to the foam. In addition to the metal foil, a metal layer that is formed by rolling a metal into a thin plate shape can also be used.

  Among the metals constituting the metal layer, aluminum is preferable in that it is excellent in incombustibility, is lightweight, is inexpensive, and is easily available. In addition, stainless steel, copper, or the like can be used depending on the application or use condition. In addition, the metal layer is not limited to one made of a single metal foil or thin plate, and a plurality of metal foils or thin plates can be used in layers.

  The thickness of the metal layer is preferably in a range that ensures sufficient nonflammability and does not impair handling properties, and is specifically 20 to 100 microns.

A black paint is applied to the surface (non-adhesion side surface) of the metal layer . The metal layer may turn black or red due to oxidation. For this reason, a black paint is applied to the metal layer surface (non-adhesive side surface) so that the appearance is not impaired. A black paint is a coating of a viscoelastic polymer such as rubber, plastic, or asphalt with a black dye made of carbon added to the metal layer surface. It has the function of preventing the oxidation of the layer and increasing the strength of the layer. In addition, since the coating film component of the paint has a viscoelastic polymer as a main component, when it is applied, the thermal conductivity of the metal layer is lowered, which also contributes to the improvement of the incombustibility of the sound absorbing foam .

Further, the skin layer can also take the form of a composite layer in which the metal layer and the inorganic fiber layer are used in combination. When the skin layer is a composite layer in which a metal layer and an inorganic fiber layer are used in combination, it is desirable that the inorganic fiber layer is on the inside (foam side) and the metal layer is on the outside.

An inorganic fiber layer consists of 1 type, or 2 or more types chosen from glass fiber, rock wool fiber, carbon fiber, and ceramic fiber. Examples of the form of the fiber layer include woven fabric, knitted fabric, non-woven fabric, and paper.

The fiber density of the inorganic fiber layer is 10 kg / m ^Three The above is desirable. 10kg / m ^Three It is because sufficient nonflammability cannot be obtained if the density is smaller than the above. Moreover, as thickness of an inorganic fiber layer, 0.5 mm or more is preferable. When the thickness of the inorganic fiber layer is less than 0.5 mm, sufficient nonflammability may not be obtained, or the handleability may be deteriorated.

  The foam and the skin layer, the metal layer constituting the skin layer, the inorganic fiber layer, and the metal layer and the inorganic fiber layer are bonded via an adhesive. The adhesive is not particularly limited. For example, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, polyamide, acrylic ester, methacrylic ester, phenol resin, epoxy resin, urea resin, polyisocyanate, or polyvinyl acetal / Examples thereof include those composed of an adhesive component made of one or a mixture selected from phenol and epoxy / nylon composite polymers.

  In addition, this invention is not limited to the following Example, It can implement freely by changing in the range described in the "Claims".

Reference example 1
Aluminium foil with a thickness of 50 microns is acrylic on one surface of a sound-absorbing foam with a thickness of 20 mm. Bonding via a system adhesive, a non-combustible sound absorbing foam was obtained.

Example 1
A noncombustible sound absorbing foam was obtained in the same manner as in Reference Example 1 except that a 50 micron thick aluminum foil coated with a black dye was adhered to the sound absorbing foam of Reference Example 1.

Reference example 2
Except for using a 20 mm-thick sound absorbing foam (a dipolgy sound absorbing foam standard type (with a heat shrinkage rate of -1.7% at 70 ° C. for 24 hours), manufactured by CCI Inc.), the same as in Reference Example 1 A non-combustible sound absorbing foam was obtained.

Example 2
A nonflammable sound-absorbing foam was obtained in the same manner as in Example 1 except that a sound-absorbing foam (a diporge sound-absorbing foam standard type (with a heat shrinkage rate of -1.7% at 70 ° C. for 24 hours) was used).

Comparative Example A non-combustible sound absorbing foam obtained by adhering a 50 micron thick aluminum foil obtained by applying the black paint of Example 1 to a sound absorbing foam having a thickness of 20 mm (Basotect, manufactured by BASF Japan Ltd.).

The sound absorptivity was evaluated for Examples 1 and 2 above , Reference Examples 1 and 2 and Comparative Examples. The sound absorption was evaluated according to the normal incidence sound absorption coefficient (JIS A 1405-1963). Specifically, using a sound tube (two types, 99 mm and 29 mm in diameter) with a speaker attached to one end and a sample attached to the other end, pure sound with a specified frequency is generated from the speaker, The sound absorption ratio of the sample when the sound is incident vertically is obtained from the sound pressure ratio of the node. The result is shown in FIG.

From FIG. 1, it is confirmed that the foams according to Examples 1 and 2 and Reference Examples 1 and 2 have excellent sound absorption (sound absorption rate) that greatly exceeds the foam of the comparative example in a frequency region below 2000 Hz. It was done.

Next, the sound insulation was evaluated for the above Examples 1 and 2, Reference Examples 1 and 2 , and Comparative Example. The sound insulation was evaluated according to the reverberation room method sound absorption coefficient test (JIS A 1416). Specifically, the sample is placed in the opening of the boundary wall (boundary floor) of two adjacent reverberation chambers (2nd and 3rd reverberation chambers in the case of a boundary wall and 2nd and 4th reverberation chambers in the case of a boundary floor). This is a method in which sound energy transmitted through one of the sound source chambers and the other as a sound receiving chamber is measured, and the sound insulation performance of the wall and floor is determined. The result is shown in FIG.

From FIG. 2, it was confirmed that the foams according to Examples 1 and 2 and Reference Examples 1 and 2 had excellent sound insulation properties that exceeded the foams of the comparative examples in the frequency region below 2000 Hz.

Next, nonflammability was evaluated for Examples 1 and 2 and Reference Examples 1 and 2 . Nonflammability was evaluated based on whether the following three requirements could be satisfied for 20 minutes after heating. (1) Does not burn. (2) No harmful deformation, dissolution, cracks, etc. occur. (3) Do not generate smoke or gas harmful to evacuation. The results are shown in Tables 1 and 2.

表１及び表２から、実施例１及び２、参考例１及び２に係るフォームは、いずれも着火や着炎はなく、煙の発生もごく僅かであり、変形も無い若しくはあってもごく僅かであり、不燃性に優れていることが確認された。また、黒色塗料を塗布した実施例１及び実施例２のフォームは、未塗布の参考例１及び参考例２の各フォームに比べて、炭化量も少なく、変形もないことから、不燃性に優れていることが確認された。尚、上記実施例１及び２、参考例１及び２に係る各フォームは、社団法人日本鉄道車両機会技術協会から「不燃性」又は「難燃性」の認定を得ている。

From Table 1 and Table 2, the foams according to Examples 1 and 2 and Reference Examples 1 and 2 are not ignited or ignited, the generation of smoke is negligible, and there is little or no deformation. It was confirmed that it was excellent in nonflammability. Also, the foams of Example 1 and Example 2 coated with black paint are less non-flammable than the uncoated foams of Reference Example 1 and Reference Example 2. It was confirmed that In addition, each form which concerns on the said Example 1 and 2 and the reference examples 1 and 2 has acquired "nonflammability" or "flame retardant" authorization from Japan Railway Vehicle Opportunity Technology Association.

The graph which showed the normal incidence sound absorption coefficient in each frequency of 100-5000 Hz about Example 1 and 2, Reference Example 1 and 2 , and a comparative example. The graph which showed the transmission loss (dB) in each frequency of 100-5000 Hz about Example 1 and 2, Reference Example 1 and 2 , and a comparative example.

Claims (7)

A sound absorbing foam,
An organic compound comprising one or more selected from a compound having a benzothiazyl group, a compound having a benzotriazole group, a compound having a diphenyl acrylate group, and a compound having a benzophenone group in the base polymer constituting the foam System high damping agent is included,
A nonflammable sound absorbing foam, characterized in that a skin layer made of a metal foil coated with a black paint having a viscoelastic polymer as a coating film component is provided on one surface of the foam. The organic high-damping agent is 1 to 100 with respect to 100 parts by weight of the base polymer constituting the foam.
The noncombustible sound absorbing foam according to claim 1, wherein the noncombustible sound absorbing foam is contained in a proportion by weight. Compounds having a benzothiazyl group are N, N-dicyclohexylbenzothiazyl-2-sulfenamide (DCHBSA), 2-mercaptobenzothiazole (MBT), dibenzothiazyl sulfide (MBTS), N-cyclohexylbenzothiazyl-2. -Sulfenamide (CBS), N-tert-butylbenzothiazyl-2-sulfenamide (B
It is any one of BS), N-oxydiethylenebenzothiazyl-2-sulfenamide (OBS), and N, N-diisopropylbenzothiazyl-2-sulfenamide (DPBS). The noncombustible sound absorbing foam according to 1 or 2. A compound having a benzotriazole group has 2- {2'-hydroxy-3 '-() having a benzotriazole having an azole group bonded to a benzene ring as a mother nucleus and a phenyl group bonded thereto.
3 ", 4", 5 ", 6" tetrahydrophthalimidemethyl) -5'-methylphenyl}-
Benzotriazole (2HPMMB), 2- {2'-hydroxy-5'-methylphenyl} -benzotriazole (2HMPB), 2- {2'-hydroxy-3'-t-butyl-5'-methylphenyl} -5 -Chlorobenzotriazole (2HBMPCB) and 2- {2'-hydroxy-3 ', 5'-di-t-butylphenyl} -5-chlorobenzotriazole (2HDBPCB) Item 3. The noncombustible sound absorbing foam according to item 1 or 2. The incombustible sound absorbing foam according to claim 1 or 2, wherein the compound having a diphenyl acrylate group is ethyl-2-cyano-3,3-diphenyl acrylate. The compound with benzophenone group is 2-hydroxy-4-methoxybenzophenone (
The noncombustible sound absorbing foam according to claim 1 or 2, wherein the nonflammable sound absorbing foam is any one of HMBP) and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (HMBPS). The non-combustible sound absorbing foam according to claim 1, wherein the metal layer is made of a metal selected from aluminum, iron, stainless steel, and copper.

Images