KR20090062155A - Polyurethane foam acoustic absorbent using dash-panel of automobile - Google Patents

Abstract

A polyurethane foam sound-absorbing material for a dash panel of a vehicle is provided to reduce the absorbed noise and to expand a route for noise absorption by using polyether polyol containing monool. A polyurethane foam sound-absorbing material for a dash panel of a vehicle comprises the followings: monool 0.01 ~3 weight% including monofunctional hydroxyl; an amine-based catalyst 0.5 ~ 2 parts by weight based on polyether polyol 100 parts by weight; a foam stabilizer 0.5 ~ 3 parts by weight; and resin premix containing a blowing agent 2 ~ 7 parts by weight. A weight ration of resin premix and the isocyanate is 1 : 0.75 ~ 1.2. An average molecular weight of the polyether polyol is 4000 ~ 6500 g/mol.

Description

Polyurethane foam acoustic absorbent using dash-panel of automobile}

The present invention is to prepare a polyurethane foam sound absorbing material using a polyether polyol containing 3% or less monool containing a monofunctional hydroxyl group, to a polyurethane foam sound absorbing material prepared using a conventional propylene oxide-based polyether polyol Compared with the polyurethane foam foam sound-absorbing material which can expand the path of the sound absorption and reduce the absorbed noise in comparison.

To this end, in the present invention, after preparing a polyether polyol prepared by reacting propylene oxide, a low molecular weight polyol is 3 wt% or less based on the total weight of the polyether polyol using a size exclusion separation method. By manufacturing the polyurethane foam foam sound absorbing material containing the polyether polyol from which the low molecular weight polyol was separated as much as possible, the sound absorption property, that is, dustproofness was greatly improved.

In general, typical noise flowing into a vehicle interior includes engine permeation noise generated from an engine and transmitted through a vehicle body or air.In order to suppress such engine permeation noise, an engine cover or a hood insulator is used in a typical vehicle. However, through these alone there is a limit and insufficient in removing the noise to the desired level.

More specifically, sound absorbing materials are applied to various locations in automobiles. For example, sound absorbing materials are installed in a dash panel that separates an engine compartment from a compartment to block noise generated from an engine compartment. A sound absorbing material for blocking is installed in the floor panel or the like.

In the dash panel, a dash outer attached to the exterior of the vehicle and a dash inner attached to the interior serve to remove most of the noise.

And, the sound absorbing material installed on the floor panel (floor panel) is installed on the floor of the floor carpet, the noise introduced by the floor carpet in the car is the noise generated from the engine flows through the body and the tire and the road surface The noise generated at the time of contact is largely classified into the noise flowing through the vehicle body. There are two ways to improve the noise, and to improve the sound absorbing performance and the sound insulating performance.

In general, sound absorption means that the generated sound energy is converted into thermal energy and extinguished as it is transmitted through the inner path of the material, and the sound insulation is reflected by the shield and blocked.

The sound absorption performance is mainly related to the internal shape and pore structure of the material, and the sound insulation performance is closely related to the density and structure of the material. That is, in order to satisfy the sound absorbing performance, many fine open cell particles such as urethane foam should be present, and in the case of felt, it is already known that fibers having low fineness should be used.

The sound absorption mechanism for polyurethane foams is the incidence at the foam surface. Attenuation by reflection, viscous resistance of air inside the cell and sound attenuation by vibration, and thermal energy conversion of vibration energy delivered to the foam. On the basis of this sound absorption mechanism, sound absorption performance is influenced by the surface condition, density and thickness of the foam, the size and shape of the cell in terms of morphology, and by the polyurethane microstructure and its physical properties in material terms. Receive. One of the morphological factors of the cell structure is the type and content of foaming agents, surfactants, and bubble openers, including components constituting polyurethane raw materials, and the relative speeds of polyurethane synthesis and foaming reactions according to catalyst or reaction temperature. Individual factors that affect the cell structure, on the other hand, directly affect the formation of polyurethane microstructures.

In addition, when the difference between the density of the surface and the sound absorbing material in the sound absorbing material, by using the principle that the energy loss is increased according to the different surface density of the sound absorbing material can exhibit more improved performance than the same surface density.

In order to improve sound insulation performance, it is a general technique to use a heavy insulation material, which is a separate sound insulation material.

As described above, in automobiles, sound absorbing materials are applied to various locations including the dash panel, the floor panel, the door panel, the interior side of the roof panel, and various other interior materials, which are the parts where noise is most introduced. Polyurethane foam or fibrous felt is used as the material of the sound absorbing material, and recently, polyethylene terephtalate (hereinafter, referred to as "PET") felt is widely used to improve sound absorption and thermal insulation performance. In order to suppress noise, a polyurethane foam is generally used as a sound absorbing material.

The vehicle sound absorbing material such as polyurethane foam has pores inside itself so that sound can enter, and the sound so absorbed is bumped into the material. To better understand noise reduction in more detail, when noise hits a material, some of it is reflected and some is absorbed. The absorbed sound vibrates the structure of the material, and the vibration energy generated by the sound is converted into heat energy, and the heat energy is dissipated. In this way, the noise is reduced.

Polyurethane foams are generally produced by the reaction of polyether polyols and isocyanates prepared through the reaction of glycerin and polypropylene oxide. By the way, the polyether polyol inevitably generates a monool containing a mono-functional hydroxyl group in the reaction process, when the molecular weight of the polyether polyol is more than 3000 g / mol monool containing a monofunctional hydroxyl group About 10% by weight. For this reason, in the polyurethane foam obtained after the reaction with isocyanate, a polyol which does not form a network structure as shown in FIG. 4 by the reaction with the isocyanate is present, which is very disadvantageous in sound absorption characteristics.

Accordingly, in the automotive industry, there is an increasing demand for a polyurethane foam sound absorbing material having excellent sound absorbing effect while maximizing the advantages of the existing polyurethane foam.

As a result of continuous studies and efforts by the present inventors to solve the problems of the conventional polyurethane foam sound absorbing material and the industrial demand, monool containing a monofunctional hydroxyl group from the polyether polyol used in the production of polyurethane foam sound absorbing material (hereinafter, " Removing mono), i.e., monools containing relatively polyfunctional hydroxyl groups by minimizing the content of monools containing monofunctional hydroxyl groups within the polyether polyols themselves (hereinafter referred to as "polyfunctional monools"). Polyurethane foam produced using polyether polyol with an increased amount of polyol) has been developed to have a network structure, and by using it as a sound absorbing material, a conventional polyurethane foam composition Sound-absorbing effect in the main frequency range than existing sound absorbing materials while making the most of its advantages And to provide a superior polyurethane foam sound-absorbing material.

The present invention for solving the above problems

Resin containing 0.5 to 2 parts by weight of amine catalyst, 0.5 to 3 parts by foaming agent and 2 to 7 parts by weight of blowing agent based on 100 parts by weight of polyether polyol containing 0.01 to 3% by weight of monool containing monofunctional hydroxyl group Premix; And

It relates to a polyurethane foam sound absorbing material for automobile dash panel, characterized in that the weight ratio of the resin premix and the isocyanate is contained in the resin premix: isocyanate = 1: 0.75 to 1.2.

The present invention relates to a polyurethane foam sound absorbing material,

Polyurethane foam sound absorbing material of the present invention because the internal structure is the same as the network structure as shown in Figure 3 compared to the existing polyurethane foam sound absorbing material is expanded path of the sound absorption and excellent in reducing the absorbed noise.

Existing polyurethane foam sound-absorbing material had a problem that the sound absorption effect is inferior because of the same internal structure as shown in Figure 4, the inventors have studied steadily about this, the same as the network structure as shown in Figure 3 polyurethane foam excellent sound absorption effect The sound absorbing material was invented. In order for the polyurethane foam sound absorbing material to have a network structure as shown in FIG. 3, a monool containing a monofunctional hydroxyl group from a polyether polyol which is a composition of the polyurethane foam sound absorbing material using a specific technique (hereinafter, “monofunctional monool”). We'll need to remove it.

Hereinafter, the present invention will be described in detail.

The present invention relates to a polyurethane foam sound absorbing material,

Resin premixes containing a polyether polyol containing an monool containing a monofunctional hydroxyl group in an amount of 0.01 to 3% by weight, an amine catalyst, a foam stabilizer and a blowing agent; And

It is characterized by including an isocyanate.

In general, polyether polyols are generally obtained by reacting glycerol (C ₃ H ₈ O ₃ , the official name of glycerin) with polypropylene oxide, in which coherent monools and multi-integral monools inevitably occur. Do it. Typically, polyols having an average molecular weight of 6500 g / mol or less are called low molecular polyols, and in the present invention, polyether polyols having an average molecular weight of less than 6500 g / mol are defined as low molecular polyether polyols. In general, when the average molecular weight of the polyether polyol is more than 3000 g / mol, it usually contains about 10% by weight or more of the coherent monool, the polyurethane foam sound absorbing material made of a polyether polyol by the inclusion of this coherent monool The content of the multi-integral monool is relatively low, so that it does not have a network structure as shown in FIG. 3 and has an internal structure as shown in FIG.

In order to remove the coherent monool from the polyether polyol, a size exclusion separation and a gel permeation chromatography commonly used in the art are used. 0.01-3 wt% or less of polyether polyol based on the total weight of the ether polyol was prepared and used. Here, the polyether polyol before separation was used a low molecular weight polyether polyol having an average molecular weight of 4000 ~ 6500 g / mol, when the average molecular weight of less than 4000 g / mol is used to reduce the mechanical properties of the final product industrial problem This is because a problem occurs that the uniformity of the foam cell structure is lowered due to the high viscosity.

The separation can be verified by gel permeation chromatography (GPC).

The polyether polyol containing 0.01 to 3% by weight of the monofunctional monool preferably has an average functional group of 2 to 5 and a hydroxyl group of 300 to 700 mg KOH / g, where the average functional group is less than 2 This is because the foam molding machine crosslinkability is poor, and the foam molding is not desired. When the crosslinking property exceeds 5, excessive crosslinking occurs and the viscosity of the reactant increases sharply, resulting in a problem that foam molding is not performed. In addition, when the hydroxyl value is less than 300 mg KOH / g polyol reactor that can react with the isocyanate is a problem that does not form a normal foam, when the excess of 700 mg KOH / g there is a problem that the viscosity rises rapidly due to excessive crosslinking reaction occurs Because.

The coherent monool is characterized by a low molecular monool having an average molecular weight of 600 g / mol or less, which is completely uniform in the reaction between glycerol (C ₃ H ₈ O ₃ , the official name of glycerin) and polypropylene oxide. It happens because you don't.

Hereinafter, the composition of the present invention and its composition ratio will be described in more detail.

The present invention

Resin containing 0.5 to 2 parts by weight of amine catalyst, 0.5 to 3 parts by foaming agent and 2 to 7 parts by weight of blowing agent based on 100 parts by weight of polyether polyol containing 0.01 to 3% by weight of monool containing monofunctional hydroxyl group Premix; And

It is characterized in that the weight ratio of the resin premix and the isocyanate is included as the resin premix: isocyanate = 1: 0.75 to 1.2.

The amine catalyst serves to promote the reaction of the isocyanate and polyol to have a network structure, the amine catalyst is pentamethylene diethylenetriamine, dimethylcyclohexylamine, tris (3-dimethylamino) propyl It is preferable to use at least one selected from hexahydrotriamine {tris (3-dimethylamino) propylhexahydrotriamine}, triethylenediamine and derivatives thereof, but pentamethylenediethylenetriamine having excellent crosslinking reaction promoting properties may be used. It is more preferable to use. In this case, when the amine catalyst is less than 0.5 parts by weight, the reaction is delayed, and curing failure occurs. When the amine catalyst is more than 2 parts by weight, the reaction occurs quickly, resulting in unfilled and cracked foam.

The foam stabilizer, which is one of the components of the present invention, serves to adjust the formation of uniform cells and to prevent the cells from being combined when the cells are formed in the foam, and to form a uniform cell. Although not particularly limited, it is possible to use an organosilicon foam stabilizer having excellent reactant dispersibility in the reaction of a polyether polyol containing a monofunctional monool and an isocyanate, and selected from silicone oil and derivatives thereof among the organosilicon foam stabilizers. It can mix and use species. When used in the range of 0.5 to 3 parts by weight based on 100 parts by weight of the polyether polyol, there is a problem that the foam molding becomes non-uniform when less than 0.5 parts by weight, and a problem that the foam formability is slowed when it exceeds 3 parts by weight.

One of the other components of the present invention, the blowing agent may use water or cyclopentane (Cyclopentane), 2 to 7 parts by weight, more preferably 2 to 5 parts by weight based on 100 parts by weight of the polyether polyol. have. Here, if the content is less than 2 parts by weight, the polyurethane foam may not be sufficiently foamed, and if it exceeds 7 parts by weight, a problem may occur in the polyurethane foam due to rapid foaming.

As for the polyurethane foam sound absorption material of this invention, it is preferable to use the said resin premix and an isocyanate in the weight ratio of resin premix: isocyanate = 1: 1: 0.75-1.2. If the weight ratio of the isocyanate to the resin premix is less than 1: 0.75, the hardness decrease problem of the final polyurethane foam sound absorbing material occurs, and if the weight ratio exceeds 1: 1.2, the elasticity decreases due to the hardness increase.

Although the said isocyanate is not specifically limited, Monoisocyanate, diisocyanate, etc. are used, but diisocyanate is preferable in this invention. The diisocyanate used in the present invention is toluene diisocyanate (hereinafter defined as "TDI"), diphenylmethane diisocyanate (hereafter defined as "MDI") and toylene diisocyanate ( Torilene diisocyanate) and derivatives thereof may be used.

In particular, the diphenylmethane diisocyanate is monomeric (4,4-diphenyl methane diisocyanate), monomeric (monomeric) 2,4-diphenylmethane diisocyanate, 2,2-di At least one selected from phenylmethane diisocyanate, polymeric 4,4-diphenylmethane diisocyanate, polymeric 2,4-diphenylmethane diisocyanate, polymeric 2,2-diphenylmethane diisocyanate and derivatives thereof It is preferable to use, and in particular, MDI used in the present invention more preferably comprises a molecular structure of the formula (1) and the average functional group is 2.0 to 3.1.

In Formula 1, n means an integer.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited by the following examples.

Example  One

100 g of glycerol (Akzo Nobel, Glycerine) and 100 g of polypropylene oxide (SKC, PO) were reacted at a reaction temperature of 60 ^o C in a high pressure reactor to prepare a polyether polyol. Polyether polyols were prepared to contain 2% by weight of monolithic monool using a size exclusion separation method using the apparatus, and separation was confirmed as shown in FIG. 2 by GPC (gel permeation chromatography).

Resin premix by mixing polyether polyol having an average molecular weight of 6000 g / mol, an amine catalyst pentamethylenediethylenetriamine, a silicon oil as an organosilicon foaming agent, and water as a blowing agent at a temperature of 20 + 1 ^o C. After the preparation, the resin premix was mixed with the resin premix and the isocyanate so that the weight ratio of isocyanate is 1: 0.91 and stirred vigorously for 7 seconds, and then injected into a mold 100 x 100 x 2.5 cm ³ polyurethane foam A sound absorbing material was prepared.

Example  2 to 6

In the same manner as in Example 1, except that Examples 2 to 6 to have a composition shown in Table 1 to prepare a polyurethane foam sound absorbing material.

Comparative example  1 to 6

In the same manner as in Example 1, except that Comparative Examples 1 to 6 to have a composition shown in Table 1 to prepare a polyurethane foam sound absorbing material.

However, Comparative Examples except Comparative Examples 3, 5 and 6 did not remove the coherent monool separately.

division Resin Premix Isocyanate Resin Premix: Isocyanate Weight Ratio Polyether polyols Amine catalyst Foam stabilizer blowing agent A B C D Pentamethylenediethylenetriamine Silicone oil Water (H ₂ O) Cyclo-pentane MDI TDI Example 1 100 - - - 0.6 One 3 - 95 - 1: 0.91 Example 2 100 - - - One 2 4 - 105 - 1: 0.98 Example 3 100 - - - 1.5 1.5 3 - 125 - 1: 1.18 Example 4 100 - - - One 1.5 - 2.5 100 - 1: 0.95 Example 5 100 - - - 1.2 1.5 - 2.5 - 110 1: 1.05 Example 6 100 - - - One 1.5 3 - - 100 1: 1.18 Comparative Example 1 - 100 - - 0.6 One. 3 - 95 - 1: 0.91 Comparative Example 2 - 100 - - One 2 4 - 105 - 1: 0.98 Comparative Example 3 - - 100 - 0.6 One 3 - 95 - 1: 0.91 Comparative Example 4 - - - 100 0.6 One 3 - 95 - 1: 0.91 Comparative Example 5 100 - - - 0.6 One 3 - 130 - 1: 1.24 Comparative Example 6 100 - - - 0.6 One 3 - 75 - 1: 0.72 The composition components used above are as follows. ① A: Polyether polyol having an average molecular weight of 6000 g / mol and containing an average of 2% by weight of a consistent monool. ② B: Polyether polyol with an average molecular weight of 6000 g / mol and no uniform monool removed. ③ C: polyether polyol having an average molecular weight of 6000 g / mol and containing an average of 3.5% by weight of a consistent monool. ④ D: Polyether polyol having an average molecular weight of 9000 g / mol and containing an average of 2% by weight of a consistent monool. ⑤ Pentamethylenediethylenetriamine: Manufacturer Tosho, trade name Toyocat DT 4. ⑥ Silicone oil: Air Product DABCO-15 ⑦ Cyclopentane: Manufacturer Sigma Aldissa ⑧ MDI: Diphenylmethane diisocyanate, Diphenyl-methane diisocyanate, manufacturer Kumho Mitsui Chemicals Cosmonate MC-70, 31.2 wt% functional group content, viscosity 197 cps / 25 ° C

Experimental Example

Polyurethane foam sound absorbing material prepared through the above Examples and Comparative Examples was carried out as follows, foam formability evaluation, sound absorption rate evaluation, gel permeation chromatography (GPC) analysis, compressive strength and compressive hardness.

Experimental Example  One

Foam appearance and formability evaluation

The foam appearance measurement was evaluated by visually confirming the surface of the polyurethane foam sound absorbing material in which the production was completed.

The foam formability evaluation measured the cream time (hereinafter referred to as "CT") and the rise time (hereinafter referred to as "RT") at the time of foam preparation. CT represents the time interval from the mixing of the foaming compositions to the time when changes in the volume and viscosity of these reaction mixtures are visually observed, and RT represents the time from mixing of the foaming composition to the end of foaming of the foam. The high molecular weight tablet-separated polyol-added foam and the general high elastic foam were molded under the same composition conditions to compare and evaluate foam formability, and the results are shown in Table 2 below.

division Foam appearance evaluation Foam Formability Evaluation Example 1 Good Good Example 2 Good Good Example 3 Good Good Example 4 Good Good Example 5 Good Good Example 6 Good Good Comparative Example 1 Good Good Comparative Example 2 Good Good Comparative Example 3 Good Good Comparative Example 4 Good Good Comparative Example 5 Good Good Comparative Example 6 Good Good

Looking at the appearance and moldability evaluation of the polyurethane foam sound absorbing material shown in Table 2,

It can be confirmed that the polyurethane foam sound absorbing material of the present invention is almost equal in appearance and formability as compared with the conventional polyurethane foam sound absorbing material.

Experimental Example  2

Sound absorption  evaluation

It was evaluated in the frequency range of 1 to 5000 Hz by the vertical incidence sound absorption rate evaluation method used to evaluate the sound absorption rate of the polyurethane foam material. In detail, the sound absorption rate was calculated from the negative decay time in the longitudinal direction of the tube using a tube having a sufficiently rigid wall surface having a cross-sectional dimension of 25 to 110 mm and a length of 45 to 25 cm. The results are shown in Table 3 below, and the configuration of the measuring device used for sound absorption evaluation is as follows.

Sound absorption coefficient (alpha) ₀ is calculated | required by following formula (1).

: 관 길이, c : 음속

: Tube length, c: Sound velocity

: 시료가 없는 시료측을 완전 반사면으로 하였을 때 잔향시간.

: Reverberation time when the sample side without sample is the complete reflection surface.

: 시료를 붙였을 때의 잔향시간.

: Reverberation time when sample is attached.

The closer the value of sound absorption coefficient (alpha) ₀ is to 1, the more excellent the sound absorption characteristic of a material is.

Classification (frequency) 1000 Hz 1500 Hz 2000 Hz 2500 Hz 3000 Hz 3500 Hz 4000 Hz 4500 Hz Example 1 0.23 0.29 0.36 0.48 0.57 0.71 0.78 0.85 Example 2 0.24 0.29 0.37 0.50 0.57 0.74 0.81 0.87 Example 3 0.23 0.28 0.36 0.52 0.59 0.68 0.80 0.87 Example 4 0.22 0.27 0.36 0.51 0.55 0.70 0.77 0.85 Example 5 0.24 0.28 0.35 0.50 0.54 0.66 0.71 0.82 Example 6 0.24 0.28 0.33 0.49 0.58 0.69 0.72 0.83 Comparative Example 1 0.23 0.27 0.35 0.38 0.45 0.53 0.58 0.67 Comparative Example 2 0.25 0.30 0.34 0.40 0.46 0.55 0.63 0.69 Comparative Example 3 0.22 0.29 0.34 0.41 0.49 0.60 0.65 0.74 Comparative Example 4 0.27 0.35 0.37 0.39 0.41 0.47 0.52 0.60 Comparative Example 5 0.25 0.26 0.34 0.45 0.55 0.67 0.77 0.81 Comparative Example 6 0.28 0.31 0.35 0.46 0.53 0.66 0.75 0.83

Looking at Table 3, the results of the sound absorption rate evaluation experiment, although the Example and Comparative Example shows a relatively similar sound absorption rate between 1000 Hz to 2000 Hz, the poly produced in Examples 1 to 6 at a frequency between 2500 Hz and 4500 Hz It can be seen that the urethane foam sound absorbing material is significantly different sound absorption rate than the polyurethane foam sound absorbing material of the comparative example.

Particularly, in Comparative Example 3, in which a polyurethane foam sound absorbing material was manufactured using a polyether polyol containing 3.5 wt% of a coherent monool, the sound absorption rate was higher than that of Comparative Examples 1, 2, and 4, but it was confirmed that the lower than the Example. From this it can be concluded that it is desirable to produce polyurethane foam sound absorbing materials using polyether polyols containing 3% by weight of a coherent monool.

And, unlike the Examples, when looking at the sound absorption rate measurement results of Comparative Examples 5 and 6 prepared out of the range of resin premix: isocyanate = 1: 0.75 to 1.2, it can be seen that the sound absorption rate is higher than that of other comparative examples, Sound absorption rate was as high as the example. From this, it can be concluded that there is no correlation between the weight ratio of the resin premix and the isocyanate and the sound absorption rate.

As a result of the sound absorption rate test results, as can be seen from the sound absorption rate evaluation test results of the polyurethane foam material produced by the manufacturing method of the present invention, the vehicle in the frequency region of interest 1000 ~ 5000Hz, more preferably 2500 ~ 5000 Hz When applied as a sound absorbing material for the excellent sound insulation performance has been shown.

Experimental Example  3

GPC  Assay

Polyurethane foam sound absorbing material prepared in Example 1 and Comparative Example 1 was subjected to gel permeation chromatography (GPC) measurement and analysis, and the results are shown in FIGS. 1 and 2, respectively. In FIG. 2, which is the experimental result of the conventional polyurethane foam sound absorbing material, when the area indicated by the arrow is shown, it can be seen that the graph is slightly raised, which indicates that a large amount of monools having a consistent capacity exist. Looking at Figure 1, unlike the results of Figure 2, since the content of the monofunctional monool is very low, it can be seen that the graph of the same portion is gentle, unlike the arrow display portion of FIG. This confirms that the coherent monool is removed from the polyether polyol using the size exclusion separation method.

Experimental Example  4

Compressive strength and Compression hardness  Experiment

The compressive strength was evaluated based on KS M 3808, and the compressive evaluation was evaluated based on KS M 3015. The results are shown in Table 4 below.

division Compressive strength (MPa) Compression Hardness (Kgf / 314㎡) Example 1 1.58 22.35 Example 2 1.60 21.23 Example 3 1.84 25.17 Example 4 1.60 22.51 Example 5 1.61 21.11 Example 6 1.59 22.34 Comparative Example 1 1.59 22.16 Comparative Example 2 1.62 23.24 Comparative Example 3 1.65 23.27 Comparative Example 4 1.63 23.03 Comparative Example 5 2.12 30.32 Comparative Example 6 1.31 18.75

Looking at the results of the compressive strength and compressive hardness shown in Table 4, it can be seen that the compressive strength and the compressive hardness are relatively increased when the weight ratio of the isocyanate to the resin premix is increased in the Examples and Comparative Examples. In the case of Comparative Example 5 in which resin premix: isocyanate = 1: 0.75 to 1.2 is exceeded, the compressive strength and the compressive hardness are too low or too high, making it unsuitable to use as a polyurethane foam sound absorbing material.

Summarizing the experimental example, it can be seen that the polyurethane foam sound absorbing material of the present invention is superior to the conventional one in terms of physical properties while excellent sound absorption performance than the conventional polyurethane sound absorbing material. Accordingly, the present invention is suitable for various machinery and sound absorbing materials for automobiles, and in particular, it is preferable to use the polyurethane foam sound absorbing materials for automotive inner or outer dash panels.

1 is a GPC (gel permeation chromatography) measurement results of the polyurethane foam sound absorbing material prepared in Example 1 by Experimental Example 3.

2 is a GPC measurement result of the existing polyurethane foam sound absorbing material prepared in Comparative Example 1 by Experimental Example 3.

Figure 3 is a schematic diagram of the internal structure of the polyurethane foam sound absorbing material of Example 1, it can be confirmed that the mesh structure.

Figure 4 is a general view of the internal structure of the existing polyurethane foam sound absorbing material of Comparative Example 1, the structure is partially broken, it can be confirmed that the mesh structure is not achieved.

Claims (9)

Resin containing 0.5 to 2 parts by weight of amine catalyst, 0.5 to 3 parts by foaming agent and 2 to 7 parts by weight of blowing agent based on 100 parts by weight of polyether polyol containing 0.01 to 3% by weight of monool containing monofunctional hydroxyl group Premix; And A polyurethane foam sound absorbing material for automobile dash panel, characterized in that the weight ratio of the resin premix and the isocyanate is contained in the resin premix: isocyanate = 1: 0.75 to 1.2. The polyurethane foam sound absorbing material for automobile dash panel according to claim 1, wherein the polyether polyol has an average molecular weight of 4000 to 6500 g / mol. The polyurethane foam sound absorbing material of claim 1, wherein the polyether polyol is formed by size exclysion sepation. The polyurethane foam sound absorbing material for automobile dash panel according to claim 1, wherein the polyether polyol has an average functional group of 2 to 5 and a hydroxyl group of 300 to 700 mg KOH / g. The method of claim 1, wherein the amine catalyst is pentamethylene diethylenetriamine, dimethylcyclohexylamine, tris (3-dimethylamino) propyl hexahydrotriamine (tris (3-dimethylamino) propylhexahydrotriamine} and triethylene Polyurethane foam sound absorbing material for automobile dash panel, characterized in that it contains at least one selected from triethylenediamine. The polyurethane foam sound absorbing material for automobile dash panel according to claim 1, wherein the foam stabilizer comprises an organosilicon foam stabilizer. The polyurethane foam sound absorbing material according to claim 1, wherein the blowing agent contains water or cyclopentane. The automobile according to claim 1, wherein the isocyanate includes at least one selected from toluene diisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate. Polyurethane foam sound absorbing material for dash panel. The polyurethane foam sound absorbing material for automobile dash panel according to any one of claims 1 to 8, which is used to absorb a frequency of 1000 to 4500 Hz.

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