JPH07144977A - Sound-absorbing composite compact and its production - Google Patents

Abstract

PURPOSE:To improve the adsorptivity, heat-insulating property and in combustibility in the wide frequency region by placing an inorg. fiber sheet layer in a specified cured layer, integrating both layers and compacting the product into a sheet. CONSTITUTION:Ten to 30 pts.wt. of alkali silicate (expressed in terms of 40wt.% solid) and 10-25 pts.wt. of silicon (alloy powder) are added to 100 pts.wt. of a foamed vitreous bead having 0.2-8mm diameter and 20-80% porosity to obtain a mixture. The mixture is injected into a formwork 1 having degassing holes 2, a fiber sheet layer 5 having a slightly smaller size than the inner dimensions of the formwork 1 is laid thereon at a distance from the peripheral wall of the formwork so that the thickness of the layer 5 is controlled to 4/10-7/10 of the total thickness, and then the mixture is packed to cover the surface and end of the layer 5. The mixture is cured at ordinary temp., the layer 5 is placed in the cured layers 4 and 4' and integrated, and then the integrated material is formed into a sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound-absorbing composite molded article which is useful as a lightweight heat insulating wall / ceiling / roofing material having a high sound absorbing property and a method for producing the same.

[0002]

2. Description of the Related Art In JP-A-60-65777, a lightweight non-combustible molded article is prepared by mixing and molding an inorganic lightweight powder such as pearlite, an alkali silicate binder, and a curing agent made of silicon or a silicon alloy. It is disclosed that
No. 62-7681 discloses that an inorganic heat insulating material is obtained by mixing a granular inorganic foam such as obsidian and vermiculite with a curing agent composed of a silicic acid alkali binder, metallic silicon powder and phosphate to obtain an inorganic heat insulating material. It is known to manufacture various molded bodies by mixing foamed particles with an alkali silicate solution and silicon or a silicon alloy and molding the mixture.

However, in the cases disclosed above, from the viewpoint of the function as a sound absorbing material, it is not possible to obtain an excellent sound absorbing coefficient in a wide frequency range of sound. The present invention solves the above problems, and provides a sound absorbing composite molded article having sound absorbing properties in a wide frequency range, and having heat insulating properties and nonflammability, and a method for producing the same.

[0004]

DISCLOSURE OF THE INVENTION According to the present invention, an inorganic fiber sheet layer is internally integrated into a hardened layer composed mainly of glassy foamed particles, an alkali silicate liquid, and silicon or silicon alloy powder to form a plate. A sound-absorbing composite molded article formed into a shape, and the thickness of the fiber sheet layer in the sound-absorbing composite molding is 4/10 to 7/10 of the total thickness. And 100 glassy foam particles in the molding frame.
Parts by weight, 10 to 30 parts by weight of alkali silicate liquid (but solid content 40 wt
%), And a mixture of 10 to 25 parts by weight of silicon or silicon alloy powder, and a fiber sheet layer of a size smaller than the inner size of the molding frame is laid on the mixture at a distance from the peripheral wall of the frame. The surface and end of the fiber sheet layer are covered with a mixture of the same glassy foam particles, alkali silicate liquid, and silicon or silicon alloy powder as in the above mixture, and the mixture is directly cured at room temperature to integrally integrate the fiber sheet layer. It consists of things that I tried to incarnate.

In the present invention, as glassy expanded particles, natural glass expanded particles such as shirasu balloon and expanded perlite, and artificial glass such as soda lime silica type glass, alumino lime silicate type glass and aluminoborosilicate type glass. Foam particles can be used. It is preferable to use a glassy foamed product such as Cerafoam manufactured by Central Glass Co., Ltd., in which scrap glass discharged during cutting and polishing is sized to a proper particle size.

The particle size and porosity of the glassy foamed particles are not specified, and a wide range of particle sizes and porosities having a particle size of about 0.2 to 8 mm and a porosity of about 20 to 90% can be adopted.

The alkali silicate liquid acts as a binder, and a commonly used sodium silicate aqueous solution may be used. Its SiO ₂ / Na ₂ O molar ratio is on the order of 2 to 3, and the sodium silicate concentration in the aqueous solution is It is around 40wt%.

The addition ratio of the alkali silicate liquid to the glassy foam particles is 10 to 30 parts by weight based on 100 parts by weight of the glassy foam particles. If the amount is less than 10 parts by weight, it is difficult for the alkali silicate liquid to spread over the entire surface of the glassy foamed particles, resulting in insufficient adhesion. On the other hand, if it exceeds 30 parts by weight, not only the binder becomes excessive, but the cost rises, but also the moldability, the durability of the obtained molded product, the heat resistance, etc. are deteriorated.

Among silicon and silicon alloy powders, ferrosilicon or ferrosilicon-containing residue (ferrosilicon dust) obtained when ferrosilicon is produced and purified can be used as the most general one. Silicon (alloy) powder acts as a curing agent, and the reaction between the alkali content in the alkali silicate liquid and silicon in the silicon (alloy) powder further generates and hardens alkali silicate, and hydrogen and excess water (steam) ) Is released, and the release trace remains as pores. The above reaction is an exothermic reaction, and reaches about 100 ° C. even at room temperature, whereby water is also dissipated and it is cured.

The addition ratio of the silicon (alloy) powder to the glassy foam particles is approximately 10 to 25 parts by weight in proportion to the addition amount of the alkali silicate liquid. If the amount is less than 10 parts by weight, the effect as a curing agent cannot be sufficiently achieved, and if the amount exceeds 25 parts by weight, the amount becomes excessive and the loss occurs accordingly. Incidentally, in order to obtain a molded product having a low specific gravity and a high porosity, an amount close to the upper limit of the above range in combination with the addition amount of the alkali silicate liquid to the glassy foamed particles is obtained to obtain a high specific gravity and a low porosity. In this case, similarly, an amount close to the lower limit of the above range may be added together with the addition amount of the alkali silicate liquid.

The bulk specific gravity of the hardened layer can be increased by appropriately combining the glassy foamed particles, the alkali silicate solution, and the silicon (alloy) powder.
It can be adjusted to about 0.3 to 1.5.

The fiber sheet layer is not particularly limited, but various commercially available inorganic short fiber yarns are usually used.
(Rock wool, slag wool, glass wool, etc.), glass chopped strands or long glass fiber threads bonded and molded with a phenol resin, polyester resin, or other thermosetting resin binder can be used.

These fiber sheets are commercially available with a bulk specific gravity of 0.01 to 0.20 depending on the degree of accumulation of the fibers, but the fibers are densely accumulated, and therefore, they do not expand so much when filling the hardened layer during molding. A material having a bulk specific gravity of about 0.10 to 0.20, which does not shrink and is relatively tough and easy to mold, can be suitably used.

In producing the sound absorbing composite molded article,
First, a molding frame having gas vent holes in the side frame and the lid is prepared, and a mixture of glassy foam particles and silicon (alloy) powder in a predetermined ratio is kneaded with a predetermined amount of alkali silicate liquid to prepare a mixture. Then, a fiber sheet of a size smaller than the molding frame is laid apart from the peripheral wall of the frame, and the same glassy foamed particles, alkali silicate liquid, and silicon (alloy) powder are placed on it. By filling the mixture, setting the lid and leaving it for 30 minutes to 1 hour, then removing from the mold and drying,
It is possible to obtain a sound absorbing composite molded body in which the fibrous sheet layer is integrally integrated in the cured layer.

The attached FIG. 1 shows a state in which a molding frame is filled with a raw material and cured, 1 is a molding frame, 2 and 2 are gas vent holes provided in the frame, 4 is a cured layer cast at the beginning, 4'represents a cured layer filled later, and 5 represents a fiber sheet layer.

It is not necessary that the mixture of the above-mentioned casting (cured layer) and the mixture filled afterward (cured layer) have the same ratio of each component material, but the ratios should be mutually changed and the bulk specific gravity should be changed. You can also

Since the fibrous sheet is made of flexible fibers, the adhesion to the hardened layer is insufficient, and therefore the end of the fibrous sheet is covered with the hardened layer. When manufacturing a large-sized product such as a molded product exceeding 1 m □, there is a risk that peeling may occur if a large-sized fiber sheet is covered and locked only at the edges, but multiple small-sized sheets may be used as the fiber sheet. It may be designed as appropriate by laying each other at intervals.

The thicker the sound-absorbing composite molded article, the higher the sound-absorbing performance. However, when it is mounted on a wall or other body,
It is suitable to set it to about 10 mm to 30 to 40 mm.

Generally, the cured layer has excellent sound absorbing performance in the short to medium wavelength region, and the fiber sheet layer has excellent sound absorbing performance in the long wavelength region. The thickness of the fibrous sheet layer in the composite molded body is 4% of the total thickness in order to obtain sound absorbing performance over a wide frequency range.
The range is from / 10 to 7/10. When it is less than 4/10, the ratio of the hardened layer is relatively increased and the sound absorption performance in the long wavelength region is inferior. The ratio of the hardened layer is reduced and the sound absorption performance in the short to medium wavelength region is poor.

As described above, according to the present invention, since the fibrous sheet layer is internally provided in the hardened layer, the function and effect of having a high sound absorbing performance in a wide frequency range are exhibited, and at the same time when the hardened layer is hardened at the time of molding, it is possible to perform simultaneous integration. It has the advantage that it can be molded into a sheet and that the separation of the cured layer and the sheet layer can be suppressed.

[0021]

【Example】

[Example 1 and Comparative Examples 1 and 2] (Materials under test) Central Glass Co., Ltd. trade name Cerafoam processing wastes of vitreous foamed molded product have a particle size of 6
mm or less and 0.2 mm or more were crushed and sized to obtain glassy foam particles. The bulk specific gravity is 1.0 to 1.7, and the porosity is about 60 to 35%. Separately, commercially available ferrosilicon powder with a particle size of 50 μm or less, and
A No. 3 sodium silicate aqueous solution consisting of Na ₂ O.3SiO ₂ was prepared.
The solid concentration of sodium silicate is 40 wt%.

As the inorganic fiber sheet, soda lime silica glass fiber produced by Central Glass Wool Co., Ltd. was collected in each set thickness and bonded with a phenol resin binder. The thickness of the fiber sheet is
There are 3 types of 8mm, 10mm and 14mm, and the bulk density is 1.0
Is.

(Preparation of Sample) Example 1; 20 parts by weight of ferrosilicon powder was added to 100 parts by weight of glassy foam particles and mixed, and further 26 parts of sodium silicate aqueous solution was added.
The mixture obtained by adding and kneading parts by weight was cast as a lower layer side into a molding frame having gas vent holes in a frame side portion and a lid portion prepared in advance, and the glass fiber sheet having a thickness of 10 mm was laid thereon.

The glass fiber sheet had a size of 260 mm × 260 mm with respect to the frame size of 300 mm × 300 mm, and the glass fiber sheet was arranged so as to be located in the approximate center with a space from the peripheral wall of the frame.

Furthermore, a glassy foamed granule similar to the above is further formed thereon.
After filling the mixture consisting of 100 parts by weight, 20 parts by weight of ferrosilicon powder, and 26 parts by weight of aqueous solution of sodium silicate, set the lid, let it stand for about 1 hour to cure, and further remove the mold and let it dry, then leave it in place. A molded body sample indicated by reference numeral 3 was prepared. The molded product has a thickness of 6 mm and a hardened layer of 5 mm each, and approximately 10
The fiber sheet layer of mm was sandwiched, and the end surface of the fiber sheet was covered with the cured layer, and the thickness ratio of the fiber sheet layer was about 1/2 of the whole.

COMPARATIVE EXAMPLE 1 20 parts by weight of ferrosilicon powder was added to 100 parts by weight of glassy foamed particles and mixed, and 26 parts by weight of an aqueous solution of sodium silicate was added and kneaded. After casting in a molding frame having a gas vent hole, a lid was set, the mold was left to stand for about 1 hour to cure, and the mold was removed and left to dry to prepare a comparative sample. The thickness of the sample was 22 mm, which was almost the same as in Example 1.

Comparative Example 2 For comparison, a glass fiber sheet having a thickness of 10 mm similar to the fiber sheet adopted in Example 1 was used, and two glass fiber sheets were laminated with an epoxy adhesive to give a thickness of 20 mm. . The following measurements were performed on each of the obtained samples.

(Measurement) Measurement of bulk specific gravity: Cut pieces of each sample (each layer) were sampled, and their volume and weight were measured to calculate the bulk specific gravity.

The bulk specific gravity of the hardened layer in Example 1 is 0.5 (a porosity of about 80% or more), and the fiber sheet layer has a bulk specific gravity of 0.1 (porosity of about 95%). The molded sample of Comparative Example 1 has a bulk specific gravity of 0.5 as in the cured layer of Example 1, and the sheet sample of Comparative Example 2 has a bulk specific gravity of 0.1 as in the fiber sheet of Example 1.

Measurement of sound absorption coefficient: According to the method specified in JIS A 1405, a sample of a predetermined size is set on the sample support part of the device, and a sound wave from a frequency of 100 Hz to 5000 Hz is gradually emitted from the sound source part to absorb the sound of the sample. The rate was measured.

The graph of FIG. 2 shows the sound absorption coefficients of Example 1, Comparative Example 1 and Comparative Example 2 at frequencies of 125 Hz to 5000 Hz, where the vertical axis represents the sound absorption coefficient and the horizontal axis represents the frequency. It can be seen that Example 1 has a wide and high sound absorbing performance in the middle to high range. On the other hand, in Comparative Examples 1 and 2, the high sound absorption area is limited to a specific range.

[Examples 2 and 3] (Sample material) The same materials as those in Example 1 and Comparative Examples 1 and 2 were adopted as raw materials.

(Preparation of sample) Example 2; 20 parts by weight of ferrosilicon powder was added to 100 parts by weight of glassy foamed particles and mixed, and further 26 parts by weight of sodium silicate solution was added and kneaded to prepare a frame side part prepared in advance. And cast as a lower layer side into a molding frame having a gas vent hole in the lid,
On top of that, a glass fiber sheet (with a thickness of 14
mm) is laid, 20 parts by weight of ferrosilicon powder is added to 100 parts by weight of the same glassy foamed particles as above, and mixed by adding 26 parts by weight of sodium silicate solution.Then, the lid is set. Then, it was left as it was for about 1 hour to be cured, and then it was released from the mold and left to dry to prepare a molded body sample.

The thickness of the molded body is 3 m in each of the upper and lower cured layers.
m, the fiber sheet layer was 14 mm, and the thickness ratio of the fiber sheet layer was 7/10 of the whole.

Example 3 20 parts by weight of ferrosilicon powder were added to 100 parts by weight of glassy expanded beads and mixed, and further 26 parts by weight of sodium silicate solution were added and kneaded, and the mixture was added to the frame side portion and lid portion prepared in advance. A lower layer side was cast into a molding frame having a gas vent hole, and a glass fiber sheet was formed thereon in the same manner as in Example 1.
(However, a thickness of 8 mm) is laid, 20 parts by weight of ferrosilicon powder is added to 100 parts by weight of the same glassy foamed particles as above and mixed, and further 26 parts by weight of sodium silicate solution is added and kneaded. Was set, left to stand for about 1 hour to cure, then demolded and left to dry to prepare a molded body sample.

The thickness of the molded body is 6 m for the upper and lower hardened layers, respectively.
m, the fiber sheet layer was 8 mm, and the thickness ratio to the total thickness of the fiber sheet layer was 4/10.

(Measurement) Bulk Specific Gravity: Bulk specific gravity was measured in the same manner as in Example 1 and Comparative Examples 1 and 2. In Examples 2 and 3, the hardened layer has a bulk specific gravity of 0.5 (porosity of about 80% or more), and the fiber sheet layer has 0.1.
(Porosity about 95%).

Measurement of Sound Absorption Coefficient; Example 1, Comparative Example 1,
The sound absorption coefficient was measured in the same manner as in 2. The graph in Figure 3 shows a frequency of 125H.
The sound absorption coefficients of Example 2 and Example 3 at z to 5000 Hz are shown in comparison with Example 1, and as is clear from the drawing, there are some differences from each other, but similar to Example 1, Example 2, It can be seen that in Example 3 as well, it has a wide range of high sound absorbing properties in the middle to high range and is effective.

Further, the sample of Example 1 was further provided with an air space (air layer) of 30 mm behind and the sound absorption coefficient was measured. As shown in Example 1'in FIG. 3, in the low sound range of 250 Hz to 500 Hz. It can be seen that also shows high sound absorption performance.

As is apparent from the above examples, the sound absorbing performance in a wide frequency range is exhibited by adopting the structure in which the fibrous sheet layer is incorporated in the hardened layer. Also,
Needless to say, since the whole is composed of an inorganic material rich in silica, it has incombustible heat resistance, and has internal pores, and thus has heat insulating properties.

[0041]

EFFECTS OF THE INVENTION According to the present invention, the structure in which the fibrous sheet layer is incorporated in the hardened layer exhibits high sound absorbing performance in a wide frequency range, and the molded product is hardened by hardening the hardened layer at room temperature. An effect that it can be easily manufactured simultaneously and integrally.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a state where a molding frame is filled with a raw material and cured in the present invention.

FIG. 2 is a graph showing a sound absorption coefficient in comparison with an example of the present invention and a comparative example.

FIG. 3 is a graph showing a sound absorption coefficient according to another mode.

[Explanation of symbols]

 1 ---- Molding frame 2. 2 ---- Gas vent hole 3 ---- Sound absorbing composite molded body 4.4 '--- Hardened layer 5 ---- Fiber sheet layer

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Claims (3)

[Claims] 1. A glass fiber foamed particle, an alkali silicate solution, and a hardened layer containing silicon or silicon alloy powder as a main material, and an inorganic fiber sheet layer is internally integrated and formed into a plate shape. Sound absorbing composite molded body. 2. The fiber sheet layer has a thickness of 4/10 to the total thickness.
The sound-absorbing composite molded article according to claim 1, which is 7/10. 3. A method for producing the sound-absorbing composite molded article according to claim 1, wherein the molding frame has glass foam particles 100.
Parts by weight, 10 to 30 parts by weight of alkali silicate liquid (but solid content 40 wt
%), And a mixture of 10 to 25 parts by weight of silicon or silicon alloy powder, and a fiber sheet layer of a size smaller than the inner size of the molding frame is laid on the mixture at a distance from the peripheral wall of the frame. The surface and end of the fiber sheet layer are covered with a mixture of the same glassy foam particles, alkali silicate liquid, and silicon or silicon alloy powder as in the above mixture, and the mixture is directly cured at room temperature to integrally integrate the fiber sheet layer. A method for producing a sound-absorbing composite molded article, which is characterized in that