JPH02289333A - Porous structure - Google Patents

Abstract

PURPOSE:To improve sound absorbing characteristics and heat insulating characteristics and to correspond to complicated material quality by continuously changing specific gravity in the thickness or surface direction of a layer. CONSTITUTION:The temp. of the wall part of a recessed mold 7 is set to a temp. range from the softening temp. of the granular material being the raw material received in the closed space formed by the recessed mold 7 and a protruding mold 8 to the pyrolysis temp. thereof, usually, to a temp. range of 150 - 240 deg.C and the temp. of the wall part 13 of the protruding mold 8 is set to temp. lower than that of the wall part 11 of the recessed mold 7, for example, about the softening temp. of the granular material being the raw material, usually, 70 - 180 deg.C. The granular material brought into contact with the high temp. wall part 11 of the recessed mold 7 is melted to become a high specific gravity layer, in other words, a fused layer 2 at last and this layer 2 changes from air permeability to air impermeability according to a degree of fusion. Since the temp. of the wall part 13 of the protruding mold 8 is lower than that of the high temp. wall part 11, the granular material from the wall part 13 to the fused layer 12 does not reach a perfect flowable state but welded at contact parts in a semi-flowable state and a porous layer 3 is formed.

Description

[Detailed description of the invention] [Industrial usage] The present invention relates to porous structures used for sound materials, heat insulation materials, etc. Continuously changing porous N! The present invention relates to a porous structure having 4.

[Conventional technology]

Porous materials such as glass wool, rock wool, and urethane foam have traditionally been used as sound-absorbing and heat-insulating materials.Porous materials such as urethane foam and steel wool are also used as filters for air purification. There is. These porous materials? ! Vacuum cleaners, heating and cooling air conditioners,
For air purification, noise reduction, insulation, and air purification processing.
In general, sound-absorbing materials have come to be widely used, and it is strongly desired by equipment manufacturers to make porous materials low-cost, high-performance, and with fewer restrictions on shape, etc. The heat insulating material is used as a lining for a non-ventilated structure, and this structure has the function of forming a part of the flow path for air flow. In addition, the filter includes a porous material (II) on the left side of the non-ventilated material to form a filter unit.

The frame acts as a flow seal to prevent flow from leaking around the porous material of the filter unit.

Such a porous structure in which a porous material and a non-porous material are combined is made by combining separate members, molding the porous material using a foaming material, and then molding the porous material. It is manufactured by adding 710 degrees of non-breathability to the inner part.

Regarding these porous structures and their manufacturing method, see, for example, Japanese Patent Application Laid-Open No. 53-113112, ``'it Vacuum Cleaner''! # Publication No. 58-52132 ``Indoor unit of air conditioner'', JP 46-1045 Publication ``Composite article consisting of a porous thermoplastic material and a thermoplastic sheet material layer fused thereto, and its manufacture Law”, Japanese Patent Publication No. 48-19
This method is disclosed in Publication No. 654, ``Method for forming soft laminated outer skin.''

[Problem to be solved by the invention]

Conventional porous structures such as those described above have a simple shape that combines porous RF4 with uniform specific gravity and layers with higher specific gravity (for example, non-porous layers), which further improves performance. In order to achieve Vf4, there was a problem that it was difficult to obtain suitable specific gravity distribution and shape, and it was difficult to obtain good characteristics such as sound characteristics and heat insulation characteristics.The present invention solves the above problems by By having a porous layer with varying specific gravity, it is possible to obtain a porous structure that has good sound absorption and heat insulation properties and can be used with complex materials. With the goal.

[Means to solve the problem]

The porous structure according to the present invention continuously changes the specific gravity in the thickness direction of one layer or in the plane direction of the mesh layer, and has poor porosity I-.

In addition, the porous book according to the present invention has a granular material forming a porous layer with a varying specific gravity in the shape of a sphere or a round shape, and further has a major axis of 0. 2~l
O(q@).

The porous structure according to the present invention has a porous layer with a different specific gravity and a solid layer with a smaller porosity than the porous layer, and the VC is The solid layer is mochiai-like and the porous layer is sparse;
This collapsible layer is made non-air permeable.

Furthermore, the porous structure according to the present invention has a plurality of pores.

It is combined with a porous squeaking solid layer of varying specific gravity, or the solid layer is made into a skin layer with a thickness of 100 microns or less.

In addition, the porous structure according to the present invention has a porous layer with a varying specific gravity of IYUvC on one side, a solid layer with a smaller porosity than this porous layer, and a solid layer with a porosity of 100 microns or less on the other side. Furthermore, the porous structure according to the present invention, which is provided with a skin layer, has a plurality of W shapes and materials as particulate materials constituting the porous layer with varying specific gravity.

[Effect]

In the present invention, a porous layer with varying specific gravity or porosity improves each PB's poetry. 3. For example, it is possible to control the frequency characteristics of sound absorption characteristics by changing the degree of change in porosity depending on the thickness, etc., and also to balance the insulation function by radiation and heat conduction.

Furthermore, if a spherical material is used, the layer state during molding will be stabilized. Note that there is a granular shape that optimizes the sound absorption properties based on the penetration depth of sound waves and the wall-to-wall viscosity effect of acoustic energy.

Ota. Sound insulation properties can be improved by layering a porous solid layer or a skin that is fused together with a non-breathable solid layer. This minimizes the acoustic impedance of the porous material and improves its sound absorption properties in the low frequency range.

The optional multi-layer material not only functions synergistically but also functions as a structure, and also contains granular materials other than clear resin particles that contribute to sound insulation, shielding, and improving the strength of the structure. [Implementation Arrangement] An implementation arrangement of the porous structure according to the present invention (hereinafter referred to as a porous multi-layered material in the form of a porous material) will be described below.

FIGS. 11(a) and 11(b) each schematically show one side of a cross section cut in the longitudinal direction of a multilayer material (1) of a solid ellipse according to the present invention. (2) is a layer with high specific gravity, I+IJ
For example, the fused layer may be either breathable or non-breathable.

(3) is a porous layer with low specific gravity; 1 is usually breathable;

The porosity changes continuously in the thickness direction. 14) is a skin layer whose specific gravity is usually between layer (2) and layer (3).

In other words, it is a fused layer with a thickness of 100 microns or less.

The multilayer material il+ has a fusion @ (2) and a porous layer (3) -
Porous layer (3) with VC @ current layer r2)
When using the skin layer (4) as a sound absorbing material, the porous layer (1) is used as a sound absorbing material.
m + 3) facing the noise source 1nll K to absorb and attenuate the sound energy and prevent the sound waves from passing through the fusion layer (2).The 219th step is to clean the multilayer material (1), that is, the sound absorbing material. It is a sectional view of the lower part showing the row fi used in the machine. In the same figure. (5) is the outer frame, +61Fi is the blower motor 'J- which is one of the noise sources. ,
The porous layer (3) is on the blower motor (6) side and the fusion layer (2) is on the outside 1111. The arrow indicates the flow of air during operation of the vacuum cleaner.

More than! For 1 & 2, blower motor a - +61
The scratching sound generated by the sound absorbing material 11) is absorbed and insulated by the sound absorbing material 11)K.

Next, the multilayer material (porous structure) (1) 5-
Configure. 417) The manufacturing method and stability of a porous layer in which the specific gravity is continuously changed in the thickness direction or in the plane direction of the layer will be explained.

First, the manufacturing method will be explained. As for the # method, a separate patent has been filed by the same author, so here we will explain the representative rows. Fig. 3 will explain the method for making sea bream using multi-layered material as shown in the second decoy. It is a sectional view of a mold configuration. 1
7) is a concave mold with one row made of a material with good thermal conductivity such as aluminum; +8) is a convex mold with one row made of aluminum -, +91i
1 is a heater that raises the temperature of the mold, and the concave mold (7
) will be heated to a higher temperature than the convex mold (8)@method■ Use thermoplastic/sealing granular material as the raw material.

To explain the case of molding a porous structure, the 7a degree of the I part I ID of the concave mold (7) is the same as the concave mold (7).
The granular material, which is the raw material, placed in the closed space t13 formed by the convex mold (8) is softened at a temperature of q degrees or more and a heat content of 1'n degrees or less.
The temperature of the sacrificial part mouth 3 of the convex shouting metal @ (8) is the same as that of the concave all mold (7
) If the temperature is lower than the temperature of the wall part fiυ of 1 row, it is usually set at 10 to 180°C near the temperature at which the granular material used as the raw material softens. Here, if lined up in the mold (71+8), A B S (acrylonitrile -bu
A thermoplastic finger granular material (diameter 0.2 to 3 mm) such as resin (softening temperature 80 to 90 degrees Celsius) is introduced, the mold is closed under pressure, and several 10 seconds to several hours + JO pigeon. This ilO heating is carried out by producing a set of the mold F7118) mentioned above, and the pressure is 1 Y/- to several tons in the heated state.
/(-7d, the granular material in contact with the high-temperature wall 00 of the concave mold (7) melts and eventually becomes a layer with high specific gravity, in other words, a fusion layer (2). However, it changes from breathable to non-breathable depending on the degree of fusion.The wall part 13 of the convex side mold (8) has a lower temperature than that of the fusion layer (2) from the wall opening j. ) The granular materials up to ) do not reach complete fluidity, but each of the 9 granular materials is in a semi-fluid state.
! Some parts are melted blue, and finally a porous layer (3) in which the above fused layer (2) and K are welded is formed. This porous layer (3) is normally breathable, but depending on the mixture of materials such as binder, it becomes non-breathable.

In this way, a layer with a high specific gravity and a porous layer with a low specific gravity can be integrally molded at the same time.

As mentioned above, the “pull 1υ” of the concave side mold (7) and the convex side mold (8
According to experiments, it is possible to obtain a completely melted, semi-fluid state by setting the temperature of the sliding part tJ3 of 1 degree to a constant temperature. (It is desirable to have a temperature difference of 0°C or more.) If the temperature of the placing part l'111 of the concave mold (7) becomes 150°C or less, it becomes difficult for one granular material to fuse, and when it reaches 240°C or more, it melts completely. becomes too advanced, making multi-layering difficult.

When the temperature of the wall (13 of the convex side mold 18) becomes 10°C or lower, each of the 0 granular materials does not melt at the contact area and becomes difficult to adhere. (When the temperature of the 6 granular materials exceeds 80°C When the diameter of the granular material becomes less than 0.21, it becomes difficult to form a four-porous layer as the pore size progresses, the pore diameter becomes smaller and the function of the multilayer material is improved, such as sound absorption properties.

Tiles that reduce insulation properties. If an attempt is made to increase the pore size, the degree of adhesion between particles will be slightly reduced, resulting in a decrease in mechanical strength. When the diameter is 31 or more.

The heat insulation properties are good, but the single-tone properties are degraded.

Is the pressure from the mold 1kl? When /i is lower, the fusion of each granular material becomes unstable, and when the pressure exceeds 6 ton /-, the degree of accumulation becomes stricter and productivity decreases.・If the heating time is less than several tens of seconds, welding will be insufficient; if it is more than 1 hour, the melting will progress too much, the boundary between the fused layer and the porous layer will become unclear, and the properties will deteriorate. The fusion layer with high specific gravity formed in the high part of the mold is 7
J [] By changing the heat temperature, heating time, etc., the thickness of the fused layer formed1 the degree of breathability (from breathable to non-breathable)
changes, so let's change it in various ways.

Porous structures with desired characteristics can be obtained.

The typical raw material for the granular material of thermo-OT plastic clear resin is pp (polypropylene).

As (acrylic styrene), styrene, etc. can be used as a binder, and methyl ethyl ketone (MKK), cellulose, varnish, acetate, etc. can be sprayed or mixed with a granular material of thermoplastic resin to form a multilayer material. The adhesion strength of each particulate material is increased, 1 mechanical strength is improved, and handling properties are improved.

Example ■-1 In the manufacturing method, 9. of the concave mold (7). The temperature of the part nt+ was set to 150°C, the temperature of the wall circle of the convex one-rule mold (8) was set to taa''c, and AB8 resin was used as 'GTR-4 (manufactured by Kikagaku Kogyo Co., Ltd.). )(grade).

Thermoplastic reciprocal granular material that softens once at 86°C.

Spherical particles 7i with a diameter of 11 are placed in a mold, and molded into a mold f71 +
81 closed. Qingmen (11103+81′l hand pheasant is 1
A little less than 10 minutes passed in this state where it was 0 (that is, QO
Continued fever-like deafness) and mold 17)! 8) The 7JO pressure in the 7i-numerical QC1 thermal state is 50 to 9
It was /-. The multilayer material C1) formed in this manner had 10 fins per fin, in which there was no fusion layer (2) or 91 fins, and only a porous layer (3).

Manufacturing method (2) The case of molding a multilayer material using thermosetting 11 fat granular material as a raw material will be explained.

In the same manner as manufacturing method ■, make a concave 10 I7 mold + 71 ring part U.
The temperature is higher than the softening temperature of the granular material and lower than thermal decomposition, and the temperature of the wall 03 of the convex mold 18 is lower than the temperature of the wall 111 of the concave mold 7. Mold 1 is set near the temperature at which the granular material softens.
If there is one row of thermosetting Meitetsu in 71 +81, it is phenol.

PBT (polybutylene terephthalate), PELT (
Particles of a granular material such as polyethylene terephthalate (I) with a diameter of about 0.2 to 3H are mixed with a binder, cellulose, adhesives, etc., and then the mold F71 +81 is closed under pressure. .

Heat for several minutes to several hours. This heating is performed using the mold fil mentioned above.
It is carried out at a set temperature of +81, and the pressing force is 1 Y/- to several tons/- in the heated state.

When doing this, the granular material that has come into contact with the high-temperature wall part α9 of the concave mold (7) is softened and adhered with a binder to form a layer with a high specific gravity, depending on the degree of softening.

Changes from breathable to non-breathable. Since the wall part (I3) of the convex side mold (8) is lower in temperature than the high temperature wall part α0, the granular material from the wall part f13 to the above-mentioned layer 12+ with high specific gravity does not reach the complete flow #h. In a semi-fluid state, each of the nine granular materials is bonded with a binder at the contact portion, and finally, the porous layer 13 bonded to the layer (2) with a high specific gravity is formed inside the porosity. The porous layer 13) is normally breathable, but becomes non-breathable when the amount of binder mixed is increased.

Manufacturing method column ■-1 In manufacturing method ■, the temperature of the concave mold (7) is set to 200°C, the temperature of the wall T13 of the convex mold (8) is set to 150°C, As a thermosetting resin, phenolic resin (manufactured by Meiwa Kasei Co., Ltd., MY-152 (
grade), granular material with a diameter of 1 dragon at a softening temperature of 190℃), and powdered cellulose 15% as a binder.
Then, the molds +71 and +81 were closed. The distance between the wall surfaces [111113 was 101]. In this state, the mold is allowed to wander for 10 minutes (that is, the heating state is maintained) and then the mold (
7) (8) was released. The pressing force in the heated state was sobg/crI. The multilayer material f11, which was molded like a scallop, had a thickness of 10 m, and the layer with a high specific gravity (2
) had no defects, only the porous layer (3).

In addition, in the above-mentioned manufacturing methods ■ and ■, the high temperature side and low @ side molds! 7) (s) This is a line in which raw materials are introduced while keeping the temperature of the wall section lll1II3 constant.For example, when both molds are at room temperature, the raw materials are introduced, and then the mold temperature is maintained at a predetermined level. A similar multilayer material can also be formed by a method in which a molded body is formed during the process of raising the temperature to .

In this case, the temperature difference between the high-temperature side mold and the low-temperature side mold when ejecting the molding was found to be possible even with a slight temperature difference of, for example, 2° C. using RFI. This difference in finish quality is due to the material of the material,
It changes depending on the properties such as size and shape, the heating rate of the mold, the pressing force, etc.

As shown in Fig. 4, there is a difference of 1 degree between the wall an of the concave mold (7) and the wall (+3) of the convex mold (8). Place part of type (8) (+1 to 1 e.g. PBT
(Polybutylene terephthalate) resin, P RP
(rtbθrr6inforced pl!Icti
cs ) + aj It may be made of a material Q4 with poor thermal conductivity such as fat, or the molds (7) and (8) may be made of the same material but have different sizes.The key point is that it depends on the material and size. Depending on the combination of the heat capacity and the size of the heat generation Mt of the heater, the mold 171! 8
) may be set transiently or at constant temperature.

Furthermore, in order to change the specific gravity of the porous layer of a multilayer material in the direction of the layer surface of the porous layer, it is only necessary to change the temperature of the mold on the low @ side along the layer surface direction. Among these molds, the porous layer portion facing the higher temperature area has a higher specific gravity, and the porous layer portion facing the lower temperature area has a smaller specific gravity.

On the other hand, in the above-mentioned manufacturing method, since the multilayer material can be integrally molded, by changing the mold, it is possible to easily handle the multilayer material having a shape of 1% in 4 pheasants in various shapes.

Next, various characteristics and applications of the porous layer manufactured in this way, in which the specific gravity is continuously changed in the thickness direction of the layer or in the plane direction of the layer, will be explained.

(1) Sound absorption characteristics Figure 5 shows the porosity (specific gravity) distribution row in the thickness direction of a 10-thickness porous structure (porous layer throughout the entire area) formed by manufacturing method ■-1. In the figure, curves A and O exhibit approximately -like characteristics in which the porosity is about 25 (%) and about 10 (%), respectively, in the thickness direction. has a porosity distribution in the thickness direction. (It changes continuously in the range of 0 to 25 (%).

When using this type of porous structure as a sound absorbing material, its sound absorbing properties become an issue. No. 61g shows the results of measuring the normal incidence sound absorption coefficients of samples having the three types of porosity distributions shown in FIG. In addition, in a sample having a porosity distribution in the thickness direction of curve B, 7F! The sound wave was incident on the side with a porosity of 10%. As can be seen from the figure, it was confirmed that the sample with the porosity distribution (track #B) had good sound absorption characteristics.

The reason for this can be considered to be as follows.In the above-mentioned measurement specified in TI8, the structure is shown in Figure 1, where the back surface of the object to be measured (porous object) (1) is a rigid wall. It is 1. Therefore, when a sound wave Gυ is incident into a porous body fil, the particle velocity of the sound wave 0υ is zero at the rigid wall surface rB.The particle velocity moves away from the rigid wall surface (7) and approaches the incident surface (
The incidence surface position G3 is relatively thick (the entrance surface position G3 is thick).As the sound wave is absorbed, the sound wave propagates through the narrow gap in the porous body (1). This is because acoustic energy is converted into thermal energy and dissipated due to the viscous effect of 41, which has a large porosity, has a small porosity, and the gap in the porous body (1) becomes narrower, resulting in a thicker viscous effect (However, as the porosity becomes smaller and the porosity increases, the sound waves become more resistant to the pores) It becomes difficult for the sound to penetrate into the solid body ill (and the sound absorption coefficient decreases. In Figures 5 and 6, the sample of curve 1 A has a very low porosity, and the sample of curve @C has a low porosity. It can be said that the porosity is too small to obtain a suitable viscous effect.Song @ B's Vi, the sound wave incidence surface of the porous body (1) (
The optimum porosity is at the maximum particle velocity 1), and the porosity increases toward the rigid wall, so that sound waves can easily enter deep into the porous body (1).

As a result, the sound absorption properties are excellent.5 Next, the effect of improving the sound absorption properties by changing the porosity (specific gravity) in the planar direction of the porous body is explained in Section 81.
shows the change in porosity of three types of samples.1 Curve A→
The porosity decreases in the order of B-eQ. The sound absorption characteristics of this type of sound are shown in Figure 9. From this figure, especially if the porosity on the sound wave incident surface side is made smaller (corresponding to the curve y6cK), the sound absorption coefficient in the low frequency range is improved. Therefore, by creating a distribution in the porosity in the plane direction of the porous body, it is possible to obtain good sound absorption characteristics in a wide frequency band. However, [warmth 10010]
The sound absorption characteristics when set to 0 will be explained.

Figure 10 shows the porosity distribution of three types of samples.
Figure 1 shows their normal incidence sound absorption coefficients. From these figures, if 1iiJ is 100C 覦i+).

It can be seen that the characteristics are opposite to those when the thickness is 10 (w). That is, when the thickness is 100 (+u+), the sound absorption characteristics are better as the porosity decreases toward the rigid wall side (curve C).

It can be thought of as follows: When the order becomes thicker, the distance that the sound waves propagate within the porous body becomes longer, so the sound waves are more likely to be reflected during the propagation (the less the amount of reflection is, the more the sound waves are reflected). To this end, it is effective to eliminate the discontinuity between the characteristic sound impedance (product of air density multiplied by sound speed) on the air side where the sound waves are incident and the acoustic impedance of the porous body7- In other words, the porosity of the porous body facing 1 m of air is made larger to match its acoustic beak impedance to the specific acoustic impedance of the air, and the porosity is gradually decreased toward the agent layer ( On the other hand, if each porous body has one strength, the sound absorption properties will be better.

As mentioned above, what is the optimal porosity distribution for porous materials?

Although it depends on the IQ, it has been confirmed that good sound absorption characteristics can be obtained by continuously changing the IQ.

Porous materials have traditionally been used as heat insulators and protective goods. The reason why a porous body has an insulating and heat-retaining effect is that the heat transfer due to the convection of the gas contained in the narrow gaps of the porous body is small (and also due to the contact transfer of the surrounding bodies that make up the porous body). It is common knowledge that this is due to the fact that the thermal conductivity is low due to the small thermal area, but porous materials are strongly influenced by radiation heat transfer.

In order to reduce the radiant heat transfer of the cage, which has a large effect on the insulation and heat retention characteristics, conventional methods have been used, for example, to coat the surface of the insulation and heat insulation material with aluminum@'5-. Although it is designed to prevent radiation from entering, productivity is poor and there are problems with durability such as peeling of parts when pasting. On the other hand, efforts are also being made to reduce the porosity of porous materials to improve radiation heat transfer. The porous structure according to the present invention has a varied porosity (specific gravity), and the degree of change can be changed as appropriate depending on the use. Therefore, by reducing the incoming porosity near the 0 surface, and increasing the porosity inside, the radiation can be blocked at the 9 surface.

In addition, since the conduction can be prevented from becoming thick, a porous body with excellent heat insulation and heat retention properties can be obtained.

Oil-impregnated bearings are usually made by impregnating a porous body with lubricating oil.

It is a self-lubricating device that does not require external lubrication.
In areas with small bearing loads, sliding bearings with forced lubrication on one part, which are widely used due to their low cost, require 20 to 9/ff 14 degrees of oil pressure on the sliding surface during la1 rotation. This causes the shaft to lift up, resulting in so-called complete lubrication (liquid lubrication) in which the shaft and bearing do not come into contact within the @ layer. - On the other hand, in oil-impregnated bearings, even if oil pressure is generated, a portion of it leaks to the outside through the porous layer of the bearing, resulting in a decrease in oil pressure, and a so-called boundary clearance occurs in which the shaft and bearing come into local contact. It's going to be this. Therefore, the bearing friction coefficient is also 0.0 in the case of 1 liter of lubrication.
2 to 0.05.

In the case of oil-impregnated bearings, the increase in η is 0.1 to 0.2, and the increase in degree is also relatively high.

The permissible bearing load of the above oil-impregnated bearings can be improved if the oil content of the sliding surface can be improved.In contrast, conventional methods have been proposed that allow oil flow to occur through the porous material without reducing the oil pressure. It is being considered.

There is a method in which the receiving surface is divided into a layer with a small pore diameter of the porous body, and the oil retaining part is divided into a layer with a large pore diameter.

That is, by joining a lining layer with a small pore diameter to an oil retaining layer, the lining layer improves the oil pressure drop. This method is described, for example, in the publication ``Oil-less Bearings'' by Yosaki, published by Agne Publishing, p. 87J. but.

In this method, the pore diameter (porosity) is discontinuous in the contiguous part of the two layers, so the self-lubricating resistance from the oil retaining layer to the lining layer is large (and the bearing load improvement effect is not fully demonstrated). There wasn't.

On the other hand, porous PI according to the present invention! In the iI structure.

The diameter of the pores in the porous bearing is reduced to a small size on the bearing surface.
Since the pore diameter can be continuously increased toward the bottom, the oil pressure is improved and the self-lubricating amount is maintained at an appropriate level, resulting in good bearing performance.

The porous structure according to the present invention can change the pore diameter (porosity), so if used as a filter, it can continuously remove dust, reduce clogging, and obtain a filter with high dust capture efficiency. In addition, outside A11
If 8 is used as a structure having a layer with a small pore diameter, it can be made into an integrated filter unit.

In addition, porous structures with porous layers with continuously varying porosity (specific gravity) can be used in fields other than those mentioned above, taking advantage of their excellent properties and ability to be used with flexible materials. It goes without saying that it can be done.

The anti-fingerprint that forms the porous layer explained above is spherical in shape? It may be 1 or 0 cylindrical, 1 yen circular, cubic, etc. Thermoplastic resin particles with whiskers tend to melt at the whiskers, so
Suitable as a raw material. In addition, for the purpose of reducing the weight of the multilayer material, for example, foamed hollow granular materials or foamable materials can be used as raw materials. Further, short fibers may be mixed into the raw material for reinforcement, and thread-like thermoplastic fat may be mixed into the raw material as a binder.

In addition, it was confirmed that there is a range in which the shape and major axis of a single granular material have better properties in terms of properties as a porous body, especially sound absorption properties. This will be explained below.

Figure 12 is a diagram showing custom-made variations in the normal incidence sound absorption coefficient (variations in characteristics with 5 samples) when the shape of the granular material is changed.5 Curve A shows that the granular material has a diameter o,
8 (fl), cylindrical shape with length 1 (dragon) 0 Curve B is spherical with diameter 1 (fl). In both cases, the thickness of the porous layer is 10 (mw), and the wave number at which the sound absorption coefficient was measured is 2 (Kllz).From the figure, the spherical one (curve B) is 0.

It can be seen that there is little difference in properties due to differences in samples, and it is extremely stable.This knock-out method has only one point of contact between the granular materials in the case of a single spherical shape.

This is probably because the layered egg of the granular material becomes stable and uniform during molding, so it is better to make it spherical (spherical or beak-shaped), especially when stability is required between samples. However, a more preferable porous structure could be obtained. It was confirmed that the sound absorption properties also differ depending on the major axis of the nine granular materials. Figure 13 shows the relationship between the long axis and sound absorption coefficient of a single granular material.The sample thickness is dlo (*N), and the measured sacrificial wave size is 2 (Ktlz). If the diameter of the granular material is made too small or too large, it becomes difficult for sound waves to penetrate into the porous body.

From the figure, the major axis of a single granular material is:

By setting it in the practical range of 0.2 to 3.0 (+*m), preferably in the range of 1.0 to 2.0 (1n),
It was confirmed that the sound absorption properties can be improved.

Next, another example of the porous structure according to the present invention will be described. This porous structure consists of a porous layer whose specific gravity is continuously changed in the thickness direction or plane direction of the layer, and a solid layer with a smaller porosity than this porous layer (a solid layer with a higher specific gravity). If one of the granular materials is a thermoplastic resin, this solid layer will be fused If1, and depending on the degree of fusion, it will vary from breathable to non-breathable.Also, one granular material will be thermoset. In the case of a porous resin, one granular material is softened and bonded with a binder to form a layer with a high specific gravity, which changes from breathable to non-breathable depending on the degree of softening, which is typical of such porous structures. The manufacturing method will be explained below.

! 1 town:! Law 1) ;n! 1■-2 In the special method, the temperature of the pipe part o9 of the concave mold (7) is set to 1
The temperature was set at 50°C, the degree of deviation of Teito 03 of the convex side mold (8) was set at 100°C, and the AH8 resin was heated to GTR-40 (grade) manufactured by Ichiki Kagaku Kogyo Co., Ltd.

A granular thermoplastic resin material with a softening temperature of 86°C.

Put spherical particles with a diameter of 1 mm into a mold, mold fil +81
closed. Wall fill (the upper female between 11 and 11 was 10 dragons) After 20 minutes of 1lJ1 (that is, the heating state was continued), the mold +71181 was opened, and the pressurizing force when the mold was still in the heating state was 100 k. #/, ffl.

The multilayer material C1) formed in this way is shown in FIG. The roughness was about 9th.

Manufacturing method column ■-3 In manufacturing method ■, set the temperature of the tube part (111 of the concave mold ear) to 180℃, and set the distance of Teito 03 of the convex mold (8) to 130℃. Then, use ABsil oil and GTR-40 (grade) manufactured by Fuuka Kagaku Kogyo Co., Ltd.

A granular thermoplastic resin material with a softening temperature of 86°C.

A spherical particle with a diameter t*x is placed in a mold, and a mold t71 +
81 closed. The distance between Qingmen αu0 was 10 dragons. After 15 minutes in this state, mold f71 +s+ '
l? Opened. Note that the pressure of one river in the case of η[l heated calyx is 1
The multilayer material previously formed was 9/- to 00 +11
is 1 drop is fQw + Among them, 1 drop of the cryolayer (2) was about 1 drop, and 1 drop of the porous layer (3) was about 9 fins, but @
! Porous layer (3)
In manufacturing process ■-2, the surface part of the mold (7) was partially integrated and a skin R with a radius of 30 μm was formed. , pipe part 113 of the 61 rule mold (8)
The temperature was set at 150°C, and a phenol resin (Meiwa Kasei Co., Ltd.
(grade), softening temperature of 190℃), granular material with a diameter of 1 dragon, and powdered cellulose as a binder, 15 tons
%, and the mold f71'8) was closed. The abbreviation between wall surfaces 111111 was IQrM. After 25 minutes elapsed in this state (that is, 0 mouth heat state R), the mold f71 +81 was opened. The multilayer material Ell has a thickness of 101
The thickness of the layer (2) with high specific gravity is about 1mm.
+The thickness of the porous layer (3) was about 9 degrees.A granular material obtained by coating a thermosetting resin with a thermoplastic resin may be used as the raw material.

The characteristics of the multilayer material (layered porous structure) formed as described above will be explained below. ■-2 and Actual ■-3 indicate the porosity (%) against the thickness (w) K of the multilayer materials manufactured by manufacturing method column ■-2 and manufacturing method column ■-3, respectively. The three-layer composite layer r21 is In the porous layer (3) of Example 1-2, which is impervious to air, the porosity changes continuously in the vertical direction, and the porosity becomes blue at one surface (low temperature side). The porosity of the porous layer (3) of Example II-3 changes continuously in the thickness direction, but the porosity reaches its maximum at the center of the porous layer (3) and reaches the surface (low temperature). The porosity decreases,
In other words, the porosity of the first surface portion is between the slightly larger porosity of the porous layer (3) and the porosity of the fused layer (2), and a partially fused skin layer 14) is formed. As long as the specific gravity is the same, it goes without saying that the smaller the porosity, the greater the problem when using a multilayer material as a sound absorbing material. Figure 16 is a curve diagram showing the normal incidence sound absorption coefficient on the specific axis, and -2 of the 5 curves showing the results of measuring the normal incidence sound absorption coefficient with the above-mentioned J Engineering 5A1405 is the multilayer material manufactured by -2 in the manufacturing method row. As can be seen from the 5 layers, each of which shows the characteristics of a 10 layer thick urethane foam, which is a conventional sound absorbing material, the normal incidence sound absorption coefficient of the multilayer material is higher than that of a conventional sound absorbing material (urethane foam). Fig. 11 is a similar caustic curve diagram of normal incidence sound absorption coefficient, and both curves are the characteristics of the multilayer material manufactured by the method described above. 2, real ■-3 are respectively eimodal sequence ■-2, l! ! ! This figure shows the characteristics of the multi-layered material of 10 degrees (manufactured by Method 1-3). The properties of manufacturing method example ■-3 are good.The knockout seems to be due to the effect of optimizing the porosity of the surface area.Secondly, the phenomenon of improving sound absorption properties due to the skin layer was clarified and on-site optimization was performed. The problem I will explain is that AB81 fat is used as the porous material.

A 10-cut sample was produced using the above-mentioned manufacturing method (■).

Figure 1B shows the actual measurement results of the porosity distribution of this sample, and Figure 1919 shows the normal incidence sound absorption coefficient with the side with the smaller porosity serving as the sound wave incidence surface. , the sound absorption coefficient was very high at low (material) waves of 40G (Hz), and moreover, good sound absorption properties with a value exceeding 90 (%) were obtained. At this time, when the low porosity part of the sound wave incidence surface 1111 of this sample was fractured and inspected using a microscope, it was found that the surface had a rough impermeable skin layer with a grindness of about 30 microns. It was done.

This phenomenon will be explained using the sound box model shown in FIG. The acoustic impedance (indicated by 2 in the figure) of the porous structure is expressed by the following equation (1).

Here *rn: acoustic resistance ω of the porous layer (3)
: Angular velocity - : Inertance j of air in porous layer 13) : Thickness ρ* of porous layer (3) : Equivalent density of air in porous layer (3) C: Inside porous 1-(3) Equivalent sound speed of air m Niskin layer 14)
The same wave number at which the areal density sound absorption coefficient becomes thicker is the case where the complex component of Equation 1 (1) becomes zero, and the frequency f becomes the following equation +21.

The areal density m of the skin layer is the inertance mfi of the porous layer
As is clear from Equation 1 (2), the frequency f at which the blue flame sound absorption coefficient is obtained can be significantly lowered to the low 8 wave range by providing a skin layer. Since the sound absorption coefficient of the porous layer is poor in the low solid wave range, the improvement measures (!: L-) are effective.The above effect of the skin layer is well known, but conventionally the skin layer was made of a porous material. I used the method of pasting it on.

In such a pasting method, the frequency at which the maximum sound absorption coefficient is obtained is lowered, but the absolute value of the sound absorption coefficient is lowered, and is usually 80 (%) or less. The reason for this is thought to be as follows.

From equation 11),! In the frequency region of large sound absorption coefficient, the acoustic impedance is 2.

Z = rfi signal. As is generally known, rn=ρC(ρ,
When C is the density of air, the speed of sound), the sound absorption coefficient is 100 (%
)become. However, when the skin layer is pasted as in the past, the resistance component at the pasted portion between the skin layer and the porous body becomes large. This is.

Since it is in series with the acoustic resistance of the porous body, the above rn=ρC
However, even when the properties were not satisfied, the instability of pasting caused variations in properties.

In contrast, in the present invention, the skin layer and the porous layer are integrally molded, so that the above-mentioned drawbacks can be eliminated.

Furthermore, we experimented with sound absorption characteristics by changing the thickness of the skin layer.
As a result, when the thickness of the skin layer exceeds 100 microns, the skin layer starts to function not as a mass but as a single elastic Ig (spring system).

On the contrary, the number of laps with the highest sound absorption coefficient of 41 increased, and the desired effect could not be obtained. Therefore. (It was confirmed that 00 microns or less is appropriate.

The above-mentioned layered porous structure has mainly been explained in the case of two layers, but it can also be a three-layered porous structure or a porous structure with arbitrary layers and arbitrary materials.

FIG. 21 shows a triple-layered porous structure (
19). When this is used together with a sound absorbing material, as mentioned above, the skin layer 14) and the porous layer (3) have excellent sound absorbing properties, and a non-oily material is used. Since the solid layer (2) acts as a sound insulator, it is possible to create a structure that effectively exhibits both sound absorbing and sound insulating functions.

In addition, when used as a heat insulating material, the skin layer 1
It is possible to create a structure in which 4J serves as a radiant heat insulator, the porous layer (3) serves as a heat conductive heat insulator, and the solid #(2) serves as a device component case.

#! 22, this is an example of a target multilayer structure, and both the solid layer (2) and the IIIK porous layer! 3) and a skin layer (4). This structure can be applied to a split or cell silencer. Figure 23 shows one example of this, in which a multilayered structure (lb) is arranged so as to divide the inside of the duct (toward) into a plurality of 41 parts, and a striped one-foot structure (lb) with excellent low-frequency sound deadening performance is used. It can be a cell type silencer.

It goes without saying that the present invention is not limited to the above-mentioned examples, but can be applied to porous structures having arbitrary layers and made of arbitrary materials depending on the application in various fields.

Further, when a material containing particles other than resin particles is used in one granular material, the function of the porous structure can be expanded.

first. (I will explain the one-piece construction method.

Tonpo row ■-1 Figure 24 is a cross-sectional view showing the metal mold (71!81 closed) where the material containing two types of grains is placed in the space αa of (7) '81. Into the mold (71), 4 is first stacked with iron grains a!9 with a major axis of approximately 0.2 milled, and filled so that the thickness is approximately IH, and then the major axis is approximately 1 vp (D A B 8
Fill the f@ fat grain tie ($1! same as that used in the sequence ■-2) so that it is about 2 fins higher than the height (10w) of the closed space aS. After filling, convex side mold (8) (
By closely joining the plate-shaped mold (in Fig. 24) to the concave mold (7), the packed layer of iron particles n9 and ABB resin particles a9 is compressed, and a packed layer of different types of particles is formed in the closed space a3. Under conditions of 5 or more to form a
Higher temperature, that is, the concave mold temperature is 150℃.

The temperature of the convex side mold is raised to 100° C. and the iron particles +9 are heated for about 20 minutes. Since the melting point of iron particles +9 is about tsoo° C., the shape of the iron particles is maintained.

On the other hand, since the hBs heavy fat grains are particularly hot in the dark part συ of the concave 1111J mold (7), the iron grains in contact with the VC also become high temperature, and the fat grains αe melt AB84, which is in contact with the iron grain α1. The molten AB S'll fat particles flow and wrap around the grains.

After heating and cooling, the molded multilayer body 11) has a thickness of 10 m, in which the fused layer (2) into which iron particles n'J are mixed has a thickness of about 1 m, and the porous layer (3) The specific gravity of the fused layer (2), which is an integrated laminate with a thickness of approximately 9, is the same as that of ABsi14 fat if it does not contain iron grains* 1.05 gr/cc. However, when iron particles were added, only the fused layer was cut and its specific gravity was measured and found to be 4.4 gr/cc. When using the porous layer of a multilayer material as a sound absorbing material and the fused layer as a sound insulating material, the higher the specific gravity of the sound insulating material, the better the sound insulation properties.
This multilayer material has excellent sound insulation properties. Previously, ABs@
In order to increase the sound insulation of a material with a specific gravity or light weight, such as fat, it was necessary to make the material thicker or to attach metal such as china plate, but with this imitation method, it would not melt. By mixing a material with a high specific gravity into the part, a multilayer material having a porous layer and a fused layer with a higher specific gravity can be easily realized.

Figure 26 is a curve diagram showing the sound insulation properties of this multilayer material. 5 curves ■-21 curves ■-1 are manufacturing method examples ■-2
A multi-layered material (without iron grains) manufactured with a thickness of 10 mm,
This shows the sound insulation properties of a multilayer material (containing iron particles) manufactured using the manufacturing method [MJ■-1] with a drop size of 101.
Measurements were made using the characteristic measurement diagram shown in Figure 5. Pipe +171 (
In 1G (Itsφ).

Insert the multilayer material (tl) to be measured, and connect the microphones 1, 42 and 9 in front and behind it.Inject sound through the speaker wire from one end of the vibro η.The other end of the pipe (I71) is closed. The closed end is filled with glass wool Qυ with a length of approximately 1000 mm, and is treated to prevent sound from being reflected at the closed end. Sound pressure level is microphone 41 I
The sound pressure level of the transmitted wave that penetrates the multilayer material is measured by the Q value of the microphone 42. The sound insulation degree (dB) of the multilayer material was evaluated by subtracting the sound pressure level of the transmitted wave from the sound pressure level of the incident wave.

As shown in FIG. 26, the one containing iron particles (Example ■-1) has improved g sound intensity by about 10 dB than the one without iron particles (Example ■-2).

In the above description, iron particles were used as particles to be mixed with resin particles.

Similar effects can be achieved with other metals, glass, and other materials with high specific gravity.
Aluminum etc. for iB shielding and heat conduction I! It is possible to mix a material that is effective in magnetic shielding, or to improve the strength of the fused layer or porous layer, glass fiber or the like may be mixed into the clear resin particles and molded.

〔Effect of the invention〕

As explained above, the present invention has a porous material whose specific gravity is continuously changed in the thickness direction of the zero layer and in the plane direction of the structured layer, so it is possible to improve the properties such as sound absorption properties and heat insulation properties. You can get a beak structure.

In addition, in the present invention, a porous layer with a changed specific gravity is used as WII.
Fi! The granular material is made into a sphere or a circular shape.

Furthermore, since the major axis is set to 0.2 to 3.0 mm, it is possible to improve the characteristics and improve the stability.

Further, according to the present invention, the porous layer has a changed specific gravity,
This porous layer is layered with a solid layer that has a smaller porosity than the porous layer, and the solid layer is a fusion layer that is bonded to the porous layer, and furthermore, this fusion III is made non-air permeable, so it absorbs sound. Characteristics etc. can be adjusted. Sincerely.

Since the interlayers are fused, a porous structure that can be used with complex materials can be obtained.

Furthermore, in the present invention, since a plurality of porous layers and solid layers having different specific gravity are combined, the field of application of the porous structure can be expanded.

In addition, in the present invention, since the solid layer is made into a skin layer with a thickness of 100 microns or less, it has even better sound absorption properties and insulation properties. ! 1 characteristic can be improved.

In addition, in the present invention, -I1 of the porous layer with varying specific gravity
On the 15th side, a solid layer with a smaller porosity than this porous layer,
Since a skin layer with a polishing thickness of 100 microns or less is provided on the other IRff surface, the characteristics can be synergistically improved, and in some cases, it can also serve as a device structure.

Furthermore, in the present invention, the granular material constituting the porous structure with varying specific gravity is made of a plurality of different shapes and materials, so that the porous structure has a 4. ＃Capability can be expanded.

[Brief explanation of drawings]

Figures 1 (A) and (B) are schematic cross-sectional views of the multilayer material (porous structure) according to the present invention, and Figure 2 shows the use of the multilayer material shown in Figure 1 with sound absorption. FIGS. 3 and 4 are sectional views of the main parts of a vacuum cleaner according to the present invention, respectively, and FIG. A curve diagram showing the porosity relative to the thickness of the porous structure. Figure 6 is a characteristic curve diagram of the normal incidence sound absorption coefficient of the porous body whose porosity curve is shown in Figure 5. Figure 1 is the vertical incidence sound absorption coefficient diagram. A configuration diagram when measuring the incident sound absorption coefficient, FIG. 8 is a curve diagram showing the porosity with respect to the thickness of the porous structure of the second embodiment a] according to the present invention, and FIG. Characteristic curve #i1 of normal incidence sound absorption coefficient of porous structure showing porosity curve, $10
The figure is a curve diagram showing the porosity versus the thickness of the porous structure of the third implementation row according to the present invention, and FIG. 11 is a curve diagram showing the porosity of the porous structure shown in FIG. FIG. 12 is a characteristic curve diagram of the normal incidence sound absorption coefficient; FIG. 12 is a diagram showing variations in the characteristic of the normal incidence sound absorption coefficient when the shape of the granular material forming the porous layer is changed; Fig. 13 is a characteristic diagram showing the relationship between the diameter of the granular material and the sound absorption coefficient, Fig. 14 is a partial cross-sectional view of the layered porous structure according to the present invention, and Fig. 15 is a characteristic diagram showing the relationship between the diameter of the granular material and the sound absorption coefficient. Curve diagram showing the porosity versus the thickness of the porous structure of the implementation row, No. 16
Figure 1 and Figure 1.gamma. are curve diagrams comparing the normal incidence sound absorption coefficient characteristics of the conventional porous structure and the porous structure whose porosity curve is shown in Figure 15. FIG. 18 is a curve diagram showing the porosity of the porous structure having a skin layer according to the present invention, and FIG. 19 is a vertical curve diagram of the porous structure having the skin layer whose porosity curve is shown in FIG. A characteristic curve diagram of the incident sound absorption coefficient, FIG. 2a is an acoustic model diagram of a porous structure for explaining the effect of the skin layer, and FIGS. 21 to 23 are diagrams showing the arbitrary layered porous structure according to the present invention. A sectional view shown. Fig. 24 is a sectional view of the mold configuration for manufacturing a porous structure containing iron particles, Fig. 25 is a characteristic measurement diagram for measuring sound insulation properties, and Fig. 261 is a diagram of two types of porous structures according to the present invention. It is a sound insulation degree characteristic curve diagram of. In the figure, (1) is a multilayer material (porous structure), +21 is a fusion layer (layer with high specific gravity, solid layer), and t3) is a porous layer. (4) is a skin layer, a9 iron grains, and tUf! resin grains. Note that the same reference numerals in Figure 1 indicate the same or corresponding parts. Figure 1 (A) Figure 2 (B) Figure 1 Diagram: Kaji Port Blue Diagram @ River <& Toya@-7 ・4g" ← Loquat, bg climb? President diameter (mm) Figure 0゜6 to 32 to 6.4 → Dragon piece (Hz)

Claims (10)

[Claims] (1) A porous structure having a porous layer in which the specific gravity is continuously changed in the thickness direction or in the plane direction of the layer, (2) The porous structure according to claim 1, wherein the granular surface material constituting the porous layer is spherical or ellipsoidal. (3) The porous structure according to claim 2, wherein the long axis of the granular material is 0.2 to 3.0 (mm). (4) A porous structure comprising the porous layer according to claim 1 and a solid layer having a smaller porosity than the porous layer. (5) The porous structure according to claim 4, wherein the solid layer is a fused layer and is fused to the porous layer. (6) The porous structure according to claim 5, wherein the fused layer is non-air permeable. (7) The porous structure according to claim 4, characterized in that a plurality of porous layers and a solid layer are combined. (8) The porous structure according to claim 4, wherein the solid layer is a skin layer having a thickness of 100 microns or less. (9) The porous layer according to claim 1 is characterized in that a solid layer having a porosity smaller than that of the porous layer is provided on one side, and a skin layer having a thickness of 100 microns or less is provided on the other side. Porous structure. (10) Claim 1, 4 or 9, characterized in that the granular material constituting the porous layer has a plurality of different shapes and materials.
The porous structure described.