JP4167636B2 - Flame retardant sound absorbing material - Google Patents

Description

  The present invention relates to a flame-retardant sound-absorbing material, and more particularly to a flame-retardant sound-absorbing material that conforms to the Federal Motor Vehicle Safety Standard FMVSS302 and can be disposed in a place where flame retardancy is required, such as an automobile engine room. About.

Conventionally, as this kind of sound-absorbing material, (a) a porous body layer made of glass wool, rock wool or the like, (b) high density and low density fiber aggregates having different air permeability of 5 to 100 times A laminate of at least two layers is known (see, for example, Patent Document 1).

However, in the sound absorbing material (a) , in order to exhibit a required sound absorbing effect with respect to noise having a frequency band of 500 Hz or less, the thickness of the porous body layer must be increased. There was a problem that the weight of the sound absorbing material was increased overall. In addition, the sound absorbing material (b) uses a viscous resistance of air, and by laminating fiber assemblies having different densities on a porous sound absorbing structure that absorbs sound by converting sound wave energy into heat energy, The high-density part is an additional mass, and the low-density part plays the role of a spring, so that a so-called dynamic vibration absorber is constructed to improve the sound absorption coefficient particularly in the low frequency band. In particular, in a so-called low frequency band of 100 Hz or less, there is a problem that a sufficient sound absorption effect cannot be obtained. In addition, sound and vibration in the low frequency band generate not only air propagation sound but also rattling of buildings and windows, so it is necessary to take measures against solid propagation sound and vibration prevention at the same time. The countermeasure was difficult.

  For this reason, the present applicant firstly uses a viscous resistance of air to convert sound wave energy into thermal energy and absorbs sound, and then a sound absorbing material in which fiber assemblies having different densities are laminated. Has been developed and applied (Japanese Patent Laid-Open No. 2003-316364).

  The sound absorbing material includes a foam layer disposed on the sound source side and a porous body layer laminated on the rigid wall side of the foam layer. Here, the foam layer is formed of a foam containing a first diol having a molecular weight of 500 to 5000, a second diol having a molecular weight of 500 or less, an inorganic filler, water as a foaming agent, and isocyanate. Moreover, the porous body layer is formed of general-purpose glass wool.

  According to the sound absorbing material having such a configuration, a so-called dynamic vibration absorber, in which the high density portion plays the role of additional mass and the low density portion plays the role of spring, can improve the sound absorption coefficient particularly in the low frequency band. .

  However, the sound absorbing material having such a configuration has the following drawbacks.

  First, since the sound absorbing material itself is not provided with flame retardancy, it cannot be disposed in a place where flame retardancy is particularly required, such as an engine room of an automobile.

Secondly, the glass wool constituting the porous layer has a weak sound absorbing effect in a low frequency region of 150 Hz or less .

JP-A-8-152890 JP 2003-316364 A

The present invention, in the first, can be disposed in an automobile engine room or the like where flame retardancy is required, the second flame-retardant sound absorption can effectively absorb the noise of the following low-frequency region 150Hz The purpose is to provide materials.

The flame-retardant sound absorbing material according to the first aspect of the present invention includes a flame-retardant foam layer disposed on the sound source side, a porous body layer laminated on the rigid wall side of the foam layer , and foam And a coating surface formed on the sound source side surface of the body layer, and a plurality of holes are formed on the sound source side of the coating surface in order to improve sound absorption characteristics .

The flame-retardant sound absorbing material according to the second aspect of the present invention includes a foam layer having flame retardancy arranged on the sound source side, a porous body layer laminated on the rigid wall side of the foam layer, and foam A film surface formed on the sound source side surface of the body layer, and the sound source side of the film surface is roughened by friction processing in order to improve sound absorption characteristics .

A third aspect of the present invention is the flame retardant sound absorbing material according to the first aspect or the second aspect , wherein the foam layer is a first diol having a molecular weight of 500 to 5000, and a second diol having a molecular weight of 500 or less. , Inorganic filler, water as a foaming agent, and isocyanate and flame retardant components are used as raw material components.

According to a fourth aspect of the present invention, in the flame-retardant sound absorbing material according to any one of the first to third aspects, the density of the foam constituting the foam layer is 50 to 500 kg / m ^3. It is what is.

According to a fifth aspect of the present invention, in the flame retardant sound-absorbing material according to the third or fourth aspect, the ratio of the hydroxyl group content contained in the first diol to the hydroxyl group content contained in the second diol is 1: 0.3-2.5.

According to a sixth aspect of the present invention, in the flame retardant sound absorbing material according to any one of the third to fifth aspects, the content of the inorganic filler is 10 with respect to 100 parts by weight of the first diol. It is -200 weight part.

According to a seventh aspect of the present invention, in the flame retardant sound absorbing material according to any one of the third to sixth aspects, the content of water as a foaming agent is 100 parts by weight of the first diol. 2 to 5 parts by weight.

According to an eighth aspect of the present invention, in the flame retardant sound absorbing material according to any one of the third to seventh aspects, the hydroxyl content of water as the first and second diols and the blowing agent is The isocyanate index (NCO / OH), which is the ratio between the total and the isocyanate content of the isocyanate, is in the range of 0.5 to 1.0.

A ninth aspect of the present invention is the flame retardant sound absorbing material according to any one of the third to ninth aspects, wherein the isocyanate index is in the range of 0.6 to 0.9. .

According to a tenth aspect of the present invention, in the flame retardant sound absorbing material according to any one of the third to ninth aspects, the content of the flame retardant is 2 to 100 parts by weight of the first diol. 100 parts by weight.

An eleventh aspect of the present invention is the flame retardant sound absorbing material according to any one of the third to tenth aspects, wherein the first diol is a polyester polyol, a polyether polyol, a polybutadiene polyol, or a polyisoprene. The diol is any diol selected from a polyol, a polyolefin polyol, a polyacrylate polyol, and a polycarbonate polyol.

According to a twelfth aspect of the present invention, in the flame retardant sound absorbing material according to any one of the third to eleventh aspects, the second diol is ethylene glycol, propylene glycol, butanediol, hexanediol, It is a diol selected from an aliphatic system such as octanediol and decanediol, or an aromatic system such as N, N-bis (2-hydroxypropyl) aniline.

A thirteenth aspect of the present invention is the flame retardant sound absorbing material according to any one of the third to twelfth aspects, wherein the inorganic filler is carbon black, silica, calcium carbonate, mica, talc, oxidation Any inorganic filler selected from magnesium, aluminum oxide, magnesium hydroxide, and aluminum hydroxide.

A fourteenth aspect of the present invention is the flame retardant sound absorbing material according to any one of the third to thirteenth aspects, wherein the isocyanate is 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate , 4,4′diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude tolylene diisocyanate, crude diphenylmethane diisocyanate, p-phenylene diisocyanate, p-xylene diisocyanate, tetramethylene-1,4-diisocyanate It is what is.

A fifteenth aspect of the present invention is the flame retardant sound absorbing material according to any one of the third to fourteenth aspects, wherein the flame retardant is magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, red phosphorus Or any other flame retardant selected from the group consisting of phosphorus, such as melamine cyanurate and melamine sulfate, silicones such as silicone powder and organopolysiloxane, and zinc borate.

A sixteenth aspect of the present invention is the flame retardant sound absorbing material according to any one of the third to fifteenth aspects, wherein the porous body layer is made of glass wool, rock wool, coarse wool felt, vegetable fiber felt. , Animal fiber felt, synthetic fiber felt, or a mixture thereof.

According to a seventeenth aspect of the present invention, in the flame retardant sound absorbing material according to any one of the first to sixteenth aspects, the combustion rate defined in the Federal Motor Vehicle Safety Standard FMVSS302 is less than 10 cm / min. It is.

According to the flame-retardant sound-absorbing material of the first to seventeenth aspects of the present invention, the following effects are obtained.

  First, since the sound absorbing material itself is provided with flame retardancy, the flame retardant sound absorbing material can be disposed in a place where flame retardancy is required, such as an engine room of an automobile, Since no halogen-based flame retardant or lead-based compound is used as a flame retardant, there is no risk of generating toxic gases during combustion, and a flame-retardant sound-absorbing material with environmental protection measures can be provided.

Secondly , the formation of holes or the like on the coating surface formed on the sound source side of the foam layer improves the air permeability of the foam layer having flame retardancy, and consequently improves the sound absorption characteristics in the low frequency region. be able to.

Hereinafter, an embodiment to which the flame-retardant sound absorbing material of the present invention is applied will be described with reference to the drawings .

Figure 1 is a sectional view showing an embodiment of the flame-retardant noise absorbing material in the present invention.

In the drawing, a flame retardant sound-absorbing material of the present invention, the foam layer 1 with a fire retardant disposed on the sound source side, a porous layer 2 laminated on rigid wall 3 side of the foam layer 1 And a coating surface 4 for improving sound absorption characteristics formed on the sound source side surface of the foam layer 1.
It has.

  As the foam layer 1 having flame retardancy, a foam having open-cell foaming is used. This is because when the sound wave enters the foam layer 1, the air in the gap portion vibrates, the sound wave energy is converted into heat energy by the viscous resistance of the air, and the sound absorption is performed. This is because the foam layer 1 itself vibrates and the sound wave energy is converted into heat energy by the viscous resistance at this time, and sound absorption is performed. In addition, the porous body layer 2 is laminated on one side of the flame retardant foam layer 1 because the foam layer 1 part acts as an additional mass, that is, a weight, and the porous body layer part is a spring. That is, it acts as a role of an air spring, and performs sound absorption by membrane vibration.

  The foam layer 1 having such flame retardancy is formed of the following foam.

  1stly, the foam uses as a raw material each component of the 1st diol of molecular weight 500-5000, the 2nd diol of molecular weight 500 or less, an inorganic filler, water as a foaming agent, isocyanate, and a flame retardant, In particular, a foam with added vibration damping properties can be obtained by making the first diol, which is the main polymer, a diol having a molecular weight of 500 to 5000, preferably 1000 to 2000. Here, when the main polymer is composed of a diol having a molecular weight of less than 500, a hard foam is obtained and vibration damping properties cannot be obtained. The body cannot be obtained. When a polyol other than triol or the diol used in the present invention is used as the main polymer, it is difficult to obtain vibration damping properties.

Second, the density of the foam is preferably in the range of 50 to 500 kg / m ³ . If the density is less than 50 kg / m ³ , the air permeability becomes too good, and the sound absorption efficiency in the low frequency region is deteriorated. If the density exceeds 500 kg / m ³ , the air permeability becomes too bad and the sound is reflected and the sound absorption is difficult. Because it becomes.

  Thirdly, as the first diol constituting the foam, polyester polyol, polyether polyol, polybutadiene polyol, polyisoprene polyol, polyolefin polyol, polyacrylic ester polyol, polycarbonate polyol and the like are suitable.

  Fourth, the second diol constituting the foam is used as a chain extender of the foam layer 1 of the present invention and plays a role of reinforcement. Here, the reason why the molecular weight is 500 or less is that if the molecular weight exceeds 500, the reinforcing effect cannot be obtained. Further, when this component is a polyol other than triol or diol used in the present invention, the reinforcing effect becomes too great and the vibration damping property is impaired.

  Fifth, the second diol constituting the foam may be an aliphatic group such as ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, decanediol, or N, N-bis (2-hydroxypropyl). Aromatic diols such as aniline are preferred.

  Here, the ratio of the hydroxyl group content contained in the first diol used in the foam and the hydroxyl group content contained in the second diol is preferably 1: 0.3 to 2.5. This is because if the ratio of the hydroxyl group content of the second diol is less than 0.3, the reinforcing effect becomes insufficient, and even if the ratio of the hydroxyl group content exceeds 2.5, no difference in effect is observed.

  Sixth, the inorganic filler constituting the foam is used for the purpose of reinforcing the foam layer and adding damping properties. This inorganic filler is preferably blended in an amount of 10 to 200 parts by weight per 100 parts by weight of the first diol having a molecular weight of 500 to 5000. If the amount is less than 10 parts by weight, the effect of adding sufficient reinforcement and vibration damping is small, and if it exceeds 200 parts by weight, the viscosity of the composition before molding becomes high and molding becomes difficult.

  Seventh, as the inorganic filler constituting the foam, carbon black, silica, calcium carbonate, mica, talc, magnesium oxide, aluminum oxide, magnesium hydroxide, aluminum hydroxide and the like are suitable.

  Eighth, water constituting the foam is used as a foaming agent. Although the addition amount of a foaming agent should just be the quantity from which a foam is obtained, 2-5 weight part is suitable with respect to 100 weight part of 1st diols with a molecular weight of 500-5000. This is because if the amount is less than 2 parts by weight, sufficient foaming is not performed, and if the amount exceeds 5 parts by weight, no significant difference in effect is observed.

  Ninthly, as the isocyanate constituting the foam, basically those used for the production of urethane foam can be used, and in particular, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude tolylene diisocyanate, crude diphenylmethane diisocyanate, p-phenylene diisocyanate, p-xylene diisocyanate, tetramethylene-1,4-diisocyanate and the like are suitable. Can be used as a mixture.

  Tenth, in order to impart moderate rigidity and vibration damping to the foam, the ratio of the total hydroxyl group content of the first diol, the second diol, and water as the blowing agent to the isocyanate content of the isocyanate It is desirable that the isocyanate index (NCO / OH) is in the range of 0.5 to 1.0, preferably 0.6 to 0.9. This is because if the isocyanate index is less than 0.5, the degree of cross-linking decreases and rigidity decreases, and if it exceeds 1.0, moderate rigidity is obtained, but vibration damping performance decreases.

  Eleventh, the flame retardant constituting the foam is used for the purpose of adding flame retardancy to the foam layer 1. The content of the flame retardant is preferably 2 to 100 parts by weight with respect to 100 parts by weight of the first diol. Examples of the flame retardant include phosphorus-based materials such as magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate and red phosphorus, nitrogen-based materials such as melamine cyanurate and melamine sulfate, silicone-based materials such as silicone powder and organopolysiloxane, boron Any flame retardant selected from zinc acid is suitable.

  12thly, you may add suitably the catalyst used for manufacture of a normal urethane foam layer, a foaming agent, a flame retardant, a plasticizer, a coloring agent, etc. to said foam according to the objective.

  Next, the porous body layer 2 is formed of the following.

  First, the porous body layer 2 is formed of glass wool, rock wool, coarse wool felt, vegetable fiber felt, animal fiber felt, synthetic fiber felt or a mixture thereof.

Second, the porous body layer 2 is formed with a loss coefficient η of 0.05 or more, an air permeability of 0.1 dm ³ / s or more, a thickness of 1 to 50 mm, and preferably 10 to 25 mm. . As described later, the porous body layer 2 having such a configuration has excellent sound absorption characteristics over a wide range from a low frequency region to a high frequency region, and is also effective in reducing solid propagation sound and vibration. Demonstrate vibration damping.

  Thirdly, the porous body layer 2 is formed of a material having a thermal conductivity of 0.1 to 0.5 W / mK or a base material made of urethane foam or a urethane foam base material blended with a thermal conductivity imparting material. Has been. Here, as the thermal conductivity imparting material, one selected from those composed of ceramics or metal materials, silicon carbide powder, alumina powder, aluminum powder, graphite, copper powder, stainless steel powder or 2 A mixture of at least seeds or graphite (the amount of graphite added is 10 to 150 parts by weight with respect to 100 parts by weight of the polyol forming the urethane foam) is used.

Next, on the sound source side of the coating surface 4, a large number of holes (not shown) are provided in a direction perpendicular to the coating surface 4 with needle-like members.

By forming such a hole in the coating surface 4, the air permeability of the coating surface 4 is improved, and as a result, the peak frequency of the sound absorption coefficient can be moved to the low frequency side.

FIG. 2 shows the sound absorption characteristics of the flame retardant sound absorbing material in the embodiment of the present invention. Here, in the figure, the thin line L4 is a sound absorption characteristic of a conventional sound absorbing material having no holes in the coating surface 4, and the dotted line L5 is 1 cm on the sound source side of the coating surface 4 by a needle-like member. ² The sound absorption characteristics of the first flame-retardant sound-absorbing material of the present invention in which 50 holes are formed per hit, the thick line L6 is 1 cm by the needle-like member on the sound source side of the coated surface 4 ² The sound absorption characteristic of the 2nd flame-retardant sound-absorbing material of this invention which formed 200 holes per hit is shown. From the figure, it can be seen that the peak frequency of the sound absorption rate in the first and second flame-retardant sound-absorbing materials of the present invention moves to the low frequency side. Therefore, if the flame-retardant sound absorbing material in the embodiment of the present invention is used, it is possible to provide a flame-retardant sound absorbing material that can cope with a low frequency region of 150 Hz or less. In addition, it replaces with formation of the hole by such a needle-shaped member, and there exists an effect similar to the above-mentioned flame-retardant sound-absorbing material, even if it subjects the coating surface 4 to friction processing by the grinder and roughens the said surface. .

The flame-retardant sound-absorbing material having such a structure is attached to a sound source such as an engine and has sound absorption performance effective in reducing air-borne sound, solid-borne sound, and vibration generated from the engine. Even if the temperature in the room or the soundproof box rises due to the above operation, the temperature rise of the porous body can be suppressed, the deterioration is not promoted, and the life is prolonged.

  The above-mentioned flame-retardant sound-absorbing material has a flame rate of UL94 flame retardant, which has a combustion speed of less than 10 cm / min as defined in the Federal Motor Vehicle Safety Standard (FMVSS) 302. Note that the test method of FMVSS 302 conforms to JIS D1201.

As described above, according to the flame-retardant sound-absorbing material of the present invention, since the sound-absorbing material itself is provided with flame retardancy, the sound-absorbing material is placed in a place requiring flame retardancy such as an engine room of an automobile. Further, since no halogen-based flame retardant or lead-based compound is used as a flame retardant, there is no possibility of generating toxic gas during combustion even if the foam layer burns. Further, the formation of holes or the like on the coating surface improves the air permeability of the coating surface, and as a result, the peak frequency of the sound absorption coefficient can be moved to the low frequency side.

  In the above-described embodiment, a single foam layer having a uniform foam density is described as the foam layer 1. However, the foam layer 1 has the following configuration, for example, first, continuous inside. A foam having bubbles, in which a thin film layer (coating surface) is integrally formed with the foam on the surface of the sound source, and secondly, for example, a thin film layer having a thickness of 1 mm or less is disposed on the sound source side One that is integrally molded with the foam on both sides of the rigid wall, third, the foam density of the open-cell foam is inclined differently in the thickness direction, and fourth, a plurality of different continuous Cell foams laminated in such a manner that the foam density is arranged in an inclined manner, Fifth, the foam density of the open cell foam is high on the sound source side, Sixth, open cell You may use what consists of a viscoelastic body as a foam.

Sectional view showing an embodiment of the flame-retardant noise absorbing material in the present invention. Explanatory drawing which shows the sound absorption characteristic of the flame-retardant sound-absorbing material which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Foam layer 2 ... Porous body layer 3 ... Rigid wall 4 ... Coating surface

Claims (17)

A flame retardant foam layer disposed on the sound source side, a porous body layer laminated on the rigid wall side of the foam layer, and a coating surface formed on the sound source side surface of the foam layer ,
A flame-retardant sound-absorbing material , wherein a plurality of holes are formed on the sound source side of the coating surface in order to improve sound-absorbing characteristics . A flame retardant foam layer disposed on the sound source side, a porous body layer laminated on the rigid wall side of the foam layer, and a coating surface formed on the sound source side surface of the foam layer ,
The flame retardant sound absorbing material, wherein the sound source side of the coated surface is roughened by friction processing in order to improve sound absorbing characteristics . The foam layer is composed of a first diol having a molecular weight of 500 to 5000, a second diol having a molecular weight of 500 or less, an inorganic filler, water as a foaming agent, an isocyanate, and a flame retardant as raw material components. The flame-retardant sound-absorbing material according to claim 1 or 2, characterized in that The flame-retardant sound-absorbing material according to any one of claims 1 to 3, wherein the density of the foam constituting the foam layer is 50 to 500 kg / m ³ . The ratio of the hydroxyl group content contained in said 1st diol and the hydroxyl group content contained in said 2nd diol is 1: 0.3-2.5, The claim 3 or 4 characterized by the above-mentioned. The flame-retardant sound-absorbing material described. The content of the inorganic filler, claims 3 to 5 flame retardant noise absorbing material according to any one, characterized in that the 10 to 200 parts by weight with respect to the first diol 100 parts by weight. The content of water as a blowing agent, a flame retardant acoustical of claims 3 to 6 any one of claims, characterized in that to said first diol 100 parts by weight of 2 to 5 parts by weight Wood. The isocyanate index (NCO / OH), which is the ratio of the total hydroxyl content of the first and second diols and water as a blowing agent to the isocyanate content of the isocyanate, is in the range of 0.5 to 1.0. It claims 3 to 7 fire retardant sound absorbing material according to any one, characterized in that in the. The isocyanate index is claims 3 to 8 fire retardant noise absorbing material according to any one that lies in the range of 0.6 to 0.9. The flame content of retardant, claims 3 to 9 any one fire retardant sound absorbing material, wherein the relative said first diol 100 parts by weight of 2 to 100 parts by weight. The first diol is any diol selected from a polyester polyol, a polyether polyol, a polybutadiene polyol, a polyisoprene polyol, a polyolefin polyol, a polyacrylate polyol, and a polycarbonate polyol. It claims 3 to 10 fire retardant noise absorbing material according to any one of to. The second diol is selected from among aliphatic systems such as ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol and decanediol, or aromatic systems such as N, N-bis (2-hydroxypropyl) aniline. claims 3 to 11 any one fire retardant sound absorbing material, wherein the selected is any diol. The inorganic filler is any inorganic filler selected from carbon black, silica, calcium carbonate, mica, talc, magnesium oxide, aluminum oxide, magnesium hydroxide, and aluminum hydroxide. It claims 3 to 12 fire retardant noise absorbing material according to any one. The isocyanate is 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4 ′ diphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate, crude tolylene diisocyanate, crude diphenylmethane diisocyanate, p-phenylene diisocyanate, p-xylene diisocyanate. , claims 3 to 13 fire retardant noise absorbing material according to any one of to, characterized in that any of the isocyanates selected from among tetramethylene-1,4-diisocyanate. The flame retardant is made of phosphorus such as magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate and red phosphorus, nitrogen such as melamine cyanurate and melamine sulfate, silicone such as silicone powder and organopolysiloxane, zinc borate inner shell claims 3 to 14 fire retardant noise absorbing material of any one, wherein the selected is any of the flame retardant. The porous layer, glass wool, rock wool, guard hair felt, vegetable fiber based felt, animal fibers based felt, claims 3 to be either or characterized by consisting of a mixture of synthetic fiber-based felts 15 The flame-retardant sound-absorbing material according to any one of the above. The flame-retardant sound-absorbing material according to any one of claims 1 to 16 , wherein a combustion rate defined in the US Federal Motor Vehicle Safety Standard FMVSS302 is less than 10 cm / min.

Images