JP7583405B2 - Insulating wall material for building ventilation ducts - Google Patents

Description

The present invention relates to insulating wall materials for ventilation ducts installed in buildings.

Ventilation ducts in buildings, such as kitchen exhaust ducts, air conditioning ducts, and chimneys, are generally equipped with heat-resistant and heat-retaining insulation. This type of insulation for ventilation ducts is made of glass fiber felt and calcium silicate.

JP 2018-112329 A JP 2020-003105 A

Fiberglass felt insulation for ventilation ducts is difficult to form into a desired wall shape, and even if it is formed, it is difficult to make it stand on its own and maintain that wall shape.
Calcium silicate ventilation duct insulation is relatively dense and heavy, and has poor dehydration properties after absorbing moisture, so it takes a long time to dry.
In view of the above circumstances, an object of the present invention is to provide an insulating wall material for ventilation ducts which can be easily formed into a desired wall shape, can stand on its own and retain its shape, is lightweight, and has good dewatering properties.

In order to solve the above problems, the present invention provides a heat insulating wall material for a ventilation duct of a building,
a heat insulating shaped body formed into a predetermined wall shape along a flow path of the ventilation duct, the heat insulating shaped body including a stacked compressed body in which defibrated glass fiber bodies are stacked and compressed, and a cured inorganic binder that is diffused in the stacked compressed body and bonds the defibrated bodies together,
The density of the stacked compressed body in the heat insulating molded body is about 190 kg/m ³ to 370 kg/m ³ .
This makes it possible to obtain a heat insulating wall material for ventilation ducts which can be easily formed into a desired wall shape, can stand on its own and retain its shape, is lightweight, and has a certain degree of dewatering properties.

It is preferable that the thickness reduction degree when both sides of the insulating wall material for ventilation ducts are sandwiched between backing plates and a bolt is inserted through the insulating wall material and a tightening torque of 20 Nm is applied is 60% or less. This ensures the tightening resistance and thus the self-supporting shape retention of the insulating wall material. From the viewpoint of ensuring the tightening resistance and thus the self-supporting shape retention of the insulating wall material, it is more preferable that the density is more than 250 kg/ ^m3 and not more than about 370 kg/ ^m3 .
In the insulating wall material for ventilation ducts, the weight loss ratio after 25 hours from the start of dehydration after water absorption to the weight at the time of substantially complete water absorption is preferably more than 6%, more preferably 8% or more, and even more preferably 9% or more at a temperature of 20°C to 30°C and a relative humidity of 60% RH to 80% RH. This ensures the dehydration of the insulating wall material. From the viewpoint of reducing the weight of the insulating wall material or ensuring dehydration, the density is more preferably about 190 kg/ ^m3 or more and less than 200 kg/ ^m3 , and from the viewpoint of ensuring dehydration, it may be more than 250 kg/ ^m3 and 370 kg/m3 ^{or less} .
The time when the heat insulating wall material is substantially completely absorbed is not limited to the time when the heat insulating wall material is completely absorbed, but may be the time when the heat insulating wall material is almost completely absorbed, specifically, the time when the heat insulating wall material is at a state where ...

The density of the stack of defibrated materials before compression is preferably about 100 kg/m ³ to 200 kg/m ³ .
It is preferable that the compressed stack has a large number of streaks extending in the thickness direction and distributed in the in-plane direction, and that the defibrated bodies are intertwined with each other in each streaky portion.
The thickness direction refers to a direction connecting an inner surface (a surface facing the flow path) and an outer surface of the insulating wall material. The in-plane direction refers to a direction along a surface perpendicular to the thickness direction, or a direction along the inner surface or the outer surface. Preferably, the stack is compressed in the thickness direction to become the stacked compressed body.

It is preferable that the heat insulating wall material for ventilation ducts further comprises a surface layer sheet covering the surface of the heat insulating molded body, and the surface layer sheet is directly bonded to the heat insulating molded body by the inorganic binder cured product on the surface. The surface may be the outer surface of the heat insulating molded body, or the inner surface or flow path defining surface.

The present invention makes it possible to obtain an insulating wall material for ventilation ducts that is easy to mold into a desired wall shape, can stand on its own and retain its shape, is lightweight, and has a certain degree of dewatering properties.

FIG. 1 is a cross-sectional view of a ventilation duct for a building according to one embodiment of the present invention. FIG. 2 is a perspective view of the building ventilation duct. FIG. 3 is an exploded perspective view of the air duct for a building. FIG. 4 is an explanatory diagram illustrating an enlarged cross-sectional structure of the insulating wall material of the building ventilation duct. 5(a) to (h) are explanatory diagrams of the manufacturing process of the heat insulating wall material.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
1 and 2 show a building ventilation duct 1. The building may be a house, an office building, or a factory. The building ventilation duct 1 may be a kitchen exhaust duct, an air conditioning duct, or a chimney (smoke exhaust duct).
The building ventilation duct 1 has, for example, a cylindrical shape.

As shown in Figures 1 and 3, the building ventilation duct 1 includes a heat insulating wall material 2 and an inner surface member 3. The heat insulating wall material 2 includes a pair of heat insulating molded bodies 10 and a surface sheet 4. The heat insulating molded bodies 10 are molded to match the wall shape of the building ventilation duct 1. For example, each heat insulating molded body 10 has a half-cylinder shape. Two heat insulating molded bodies 10 are joined together to form the cylindrical heat insulating wall material 2.
Although not shown in the drawings, adhesive tape or adhesive is used as a means for joining the heat insulating bodies 10 together.

As shown in Fig. 4, the heat insulating molded body 10 includes a stacked compressed body 11 and a cured inorganic binder 12. The stacked compressed body 11 is obtained by compressing a stack 11x in which a large number of defibrated glass fiber bodies 11a are stacked.
The glass fiber contains SiO ₂ as a main component, and may also contain Al ₂ O ₃ , Fe ₂ O ₃ , TiO ₂ , CaO, Na ₂ O, etc. The SiO ₂ content in the glass fiber is preferably about 50 to 98 wt %, more preferably about 60 to 95 wt %, and even more preferably about 70 to 95 wt %.
The defibrated glass fiber material 11a is preferably long fiber, and its average length is usually 10 mm or more, preferably 20 mm or more, more preferably 30 mm or more, and even more preferably 50 mm or more. The average diameter of the defibrated glass fiber material 11a is usually about 2 to 30 μm, preferably about 5 to 30 μm, more preferably about 5 to 20 μm, and even more preferably about 5 to 15 μm.
The density of the stack 11x (FIG. 5(d)) in which the defibrated bodies 11a are stacked before compression is preferably about 100 kg/m ³ to 200 kg/m ³ .
The density of the compressed laminate 11 in the heat insulating molded body 10 is about 190 kg/m ³ to 370 kg/m ³ .

The hardened inorganic binder 12 is formed by hardening the inorganic binder 12a ( FIG. 5( e )) that is applied to and impregnated into the stack 11x. The defibrated bodies 11a are bonded together via the hardened inorganic binder 12. The hardened inorganic binder 12 is dispersed almost uniformly over the entire area of the heat insulating molded body 10.
Preferably, the inorganic binder 12a is a thermosetting inorganic binder that is in a liquid state when applied or impregnated and is irreversibly cured by heating.
The main components of the inorganic binder 12a include silica, aluminum silicate, and other clay minerals. The weight ratio of silica to aluminum silicate is, for example, silica:aluminum silicate=50:50 to 10:90.
Furthermore, the inorganic binder 12a before hardening also contains water and other liquids. The viscosity of the inorganic binder 12a can be adjusted by the amount of liquid such as water. The aluminum silicate may be hydrated aluminum silicate.

The proportion of the defibrated body 11a in the heat insulating molded body 10 is preferably about 80 wt % to 90 wt %.
The proportion of the cured inorganic binder 12 in the heat insulating molded body 10 is preferably 10 wt % to 20 wt %.
In the heat insulating molded body 10, the remainder excluding the defibrated body 11a and the inorganic binder cured material 12 is mostly occupied by voids (air gaps or air layers). The volume ratio of the voids (air gaps) in the heat insulating molded body 10 is preferably about 0.1 vol% to 10 vol%, and more preferably about 0.5 vol% to 5 vol%. The voids are almost uniformly dispersed inside the heat insulating molded body 10.

A large number of streak portions 13 are formed in the stacked compressed body 11 and thus in the heat insulating molded body 10. These streak portions 13 each extend in the thickness direction (radial direction, up and down direction in FIG. 4) of the heat insulating molded body 10, and are arranged dispersedly in the in-plane directions (circumferential direction and axial length direction, left and right in FIG. 4 and perpendicular to the paper surface), preferably arranged at approximately uniform intervals. In each streak portion 13, the defibrated bodies 11a are intertwined with each other. The arrangement interval d ₁₃ of the streak portions 13 is preferably d ₁₃ = about 0.1 mm to 10 mm, more preferably d ₁₃ = about 0.5 mm to 5 mm.

The outer peripheral surface (surface) of the heat insulating molded body 10 is covered with a surface sheet 4 such as an aluminum glass cloth. The surface sheet 4 is directly bonded and integrated with the heat insulating molded body 10 by an inorganic binder that appears on the outer peripheral surface of the heat insulating molded body 10. No separate adhesive is used to bond the surface sheet 4.
When both sides of the insulating wall material 2 are sandwiched between backing plates made of steel plates and bolts are inserted through the material and tightened with a tightening torque of 20 Nm, the degree of thickness reduction is preferably 60% or less.
The weight loss ratio of the insulating wall material 2 after 25 hours from the start of dehydration after water absorption to the weight at the time of substantially complete water absorption is preferably more than 6%, more preferably 8% or more, and even more preferably 9% or more in an environment of a temperature of 20°C to 30°C and a relative humidity of 60% RH to 80% RH.

An inner surface member 3 is provided on the inner peripheral surface of the heat insulating wall material 2. The inner surface member 3 is formed of, for example, a metal pipe having a circular cross section. The internal space of the inner surface member 3 serves as a flow path for the fluid to be circulated, such as kitchen exhaust air, air conditioning air, and chimney exhaust gas.
The metal pipe may be a spiral pipe of a galvanized steel sheet or a stainless steel pipe. The material of the inner surface member 3 is not limited to metal, and may be resin, ceramics, paper, wood, etc. The inner surface member 3 may be formed of a sheet similar to the surface sheet 4, and may be directly bonded to the heat insulating molded body 10 by an inorganic binder that appears on the inner peripheral surface (surface) of the heat insulating molded body 10 to be integrated with it.

The building ventilation duct 1 is manufactured as follows.
As shown in FIG. 5(a), glass fibers 2a serving as a material are prepared.
5(b), the glass fibers 2a are defibrated to obtain a defibrated body 11a. The defibrated body 11a is piled up to form a stack 11x.
As shown in Fig. 5(c), the stack 11x is needle-punched by a needle punch device 5 having many needles 5a. The needles 5a have protruding barbs 5c. The high-speed reciprocating motion of the needles 5a causes the defibrated bodies 11a to intertwine with each other. As a result, as shown in Fig. 5(d), the stack 11x becomes mat-like, and many streaky portions 13 extending in the thickness direction of the stack 11x are formed.
The stack 11x at this stage has no shape retention and can be easily deformed by gravity or other external forces.

5(e), an inorganic binder 12a is applied to both surfaces (upper and lower surfaces in the figure) of the stack 11x. The application is preferably performed by a roller, but may also be performed by a spray.
Instead of coating, the stack 11x may be immersed in an inorganic binder tank to impregnate the inorganic binder 12a into the stack 11x. In this case, it is preferable to immerse the upper and lower parts of the stack 11x in the inorganic binder tank by half or less of the thickness of the stack 11x. It is preferable to form a non-impregnated layer of the inorganic binder 12a in the central part of the stack 11x in the thickness direction. This ensures a void (air layer) in the stack 11x. For this reason, in the stage from coating or impregnation to the compression molding described later, the content of the inorganic binder 12a in the stack 11x is high on both side parts (upper and lower parts) of the stack 11x and low in the central part of the stack 11x in the thickness direction. In addition, the presence rate of voids (air gaps) in the stack 11x is low on both side parts of the stack 11x and high in the central part of the stack 11x in the thickness direction.

5(f), a surface sheet 4 is attached to the upper surface (the surface facing the outer periphery of the ventilation duct 1) of the stack 11x after coating or impregnation. The surface sheet 4 is directly bonded to the stack 11x by the inorganic binder 12a that appears on the upper surface of the stack 11x.

As shown in FIG. 5(f), molds 6 and 7 having mold surfaces 6a and 7a corresponding to the finished shape (half-cylinder shape) of the heat-insulating molded body 10 are prepared separately. A heater 8 is built into at least one of the molds 6 and 7. In the figure, the heater 8 is composed of multiple rod-shaped heaters, but is not limited to this and may be a plate heater, etc.

The stack 11x is set between the molds 6 and 7.
5(g), the dies 6 and 7 are closed, and the stack 11x is compressed and molded while being heated by a heater 8. An air cylinder is preferably used for the compression.
The pressure in the heating and compression molding step is preferably about 0.1 MPa to 0.7 MPa. The heating temperature is preferably about 100° C. to 400° C. The molding time (duration of application of the pressure and heating) is preferably about 3 minutes to 30 minutes.
As a result, the stack 11x is compressed in the thickness direction to become the compressed stack body 11. Preferably, the compressed stack body 11 is compression molded so that the thickness of the compressed stack body 11 is about one half to one fourth of the thickness of the stack 11x before compression.
In addition, the heating increases the fluidity of the inorganic binder 12a, and the liquid component of the inorganic binder 12a boils, vaporizes, and dissipates. In this process, the solid component of the inorganic binder 12a diffuses throughout the entire stack 11x and becomes the cured inorganic binder 12.
Furthermore, the voids (air gaps or air layers) in the stack 11x are reduced in volume by the compression of the stack 11x, and the voids are diffused throughout the entire compressed stack 11 as the inorganic binder 12a diffuses and the liquid components evaporate and dissipate.
As shown in FIG. 5(h), the mold is then removed.

This forms the heat insulating molded body 10 having at least a part of the wall shape (semi-cylinder shape) of the duct 1. The defibrated bodies 11a throughout the entire heat insulating molded body 10 are bonded evenly via the cured inorganic binder 12, thereby ensuring the self-supporting shape retention of the heat insulating molded body 10. Furthermore, since the defibrated bodies 11a are entangled with each other in the streak-like portions 13, it is possible to more reliably prevent the stacked compressed body 11 from coming apart, and the self-supporting shape retention of the heat insulating molded body 10 can be further improved.
By using glass fiber as the main material of the heat insulating molding 10, the heat insulating properties and heat resistance of the heat insulating molding 10 can be ensured.
Furthermore, by using an inorganic binder instead of an organic binder as the binder, it is possible to ensure the heat resistance, fire resistance, and heat insulation of the heat insulating molded body 10. In addition, by uniformly dispersing voids throughout the entire heat insulating molded body 10, the heat insulation property is further improved.
A surface sheet 4 is laminated integrally on the outer peripheral surface (surface) of the heat insulating molded body 10. The surface sheet 4 is directly bonded to the heat insulating molded body 10 by the cured inorganic binder 12 on the outer peripheral surface (surface) of the heat insulating molded body 10. Since the cured inorganic binder 12 serves as a bonding means for the surface sheet 4, a separate bonding means such as an adhesive is not required.

A pair of the semi-cylindrical heat insulating molded bodies 10 are prepared.
The pair of heat insulating molded bodies 10 are placed on both sides of the inner surface member 3 which is separately prepared.
The pair of heat insulating molded bodies 10 are joined together by a joining means such as an adhesive tape or an adhesive, thereby obtaining a cylindrical heat insulating wall material 2.
In this manner, the building ventilation duct 1 is obtained. The inner surface member 3 serves to prevent the defibrated body 11a from scattering from the inner peripheral surface of the insulating wall material 2. The surface sheet 4 serves to prevent the defibrated body 11a from scattering from the outer peripheral surface of the insulating wall material 2.
According to the present invention, by preparing a mold corresponding to the wall shape of various building ventilation ducts, the shape of the heat insulating molded body 10 and therefore the shape of the heat insulating wall material 2 can be set arbitrarily.
By setting the density of the stacked compressed body 11 in the heat insulating molded body 10 to about 190 kg/m ³ to 370 kg/m ³ , a heat insulating wall material for ventilation ducts that is self-supporting and capable of retaining its shape, is lightweight, and has a certain degree of dewatering ability can be obtained.
By setting the density to 190 kg/m3 or ^more , preferably more than 250 kg/ ^m3 , and setting the degree of thickness reduction to 60% or less, the tightening resistance and therefore the self-supporting shape retention of the insulating wall material 2 for ventilation ducts can be sufficiently ensured.
By setting the density to 370 kg/m3 or ^less (but may be more than 250 kg/m3 ⁾ , preferably less than 200 kg/ ^m3 , and setting the weight reduction rate to preferably more than 6%, more preferably 8% or more, and even more preferably 9% or more, the insulating wall material 2 can be made lightweight and dewaterability as an insulating wall material 2 for a ventilation duct can be ensured.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the building ventilation duct is not limited to a kitchen exhaust hood, an air conditioning duct, or a chimney, but may be a ventilation duct or the like.
The shape of the ventilation duct is not limited to a cylindrical shape, but may be a rectangular or other polygonal cylindrical shape, or may be any other shape. The insulating wall material may be a flat plate, a curved plate, or any other shape.
The defibrated body 11a is not limited to long fibers, and may be short fibers.
The inorganic binder 12a is not limited to a thermosetting binder, and may be, for example, a water-setting binder that hardens by a hydration reaction or the like. The inorganic binder 12a may be melted by heating to bond the defibrated bodies 11a together, and then hardened by cooling. The inorganic binder 12a may contain a dispersion medium or a solvent. The dispersion medium or solvent may be vaporized when heated. The dispersion medium or solvent may be water.
A surface layer sheet 4 may be provided on the inner surface (the surface defining the duct flow path) of the wall-shaped heat insulating molded body. The surface layer sheet 4 may be directly bonded to the heat insulating molded body by an inorganic binder on the inner surface of the heat insulating molded body. The surface layer sheet may be omitted.

The present invention is not limited to the following examples.
In Example 1, the clamping force resistance according to the density of the insulating wall material was verified.
Samples 1 to 4 of a heat insulating wall material were prepared, each of which was made of a heat insulating molded body containing a compressed laminate and a cured inorganic binder.
The length and width of the insulating wall material samples 1 to 4 were approximately 100 mm x approximately 100 mm, and the initial thickness (before tightening) was 19.7 mm to 20.7 mm. The thickness was measured at four points on each of the insulating wall material samples 1 to 4, and the average value was used (similar to Example 2).
The initial (pre-clamping) densities of the insulating wall material samples ranged from 198 kg/m ³ to 367 kg/m ³ .
Both sides of each of the insulating wall material samples 1 to 4 were sandwiched between a pair of backing plates made of steel plates, a bolt was passed from one backing plate through the insulating wall material samples 1 to 4 and the other backing plate, a nut was screwed in, and the degree of thickness reduction ( (initial thickness - thickness after tightening ) / initial thickness) was measured when a tightening torque of 20 Nm was applied.
As shown in Table 1, the measurement results were 59%, 50%, 42%, and 30%, respectively, confirming that sufficient self-supporting shape retention was ensured for use as an insulating wall material for ventilation ducts.

In Example 2, the dehydration after water absorption according to the density of the insulating wall material was examined.
Heat insulating wall material samples 5 to 8 were prepared, each of which was made of a heat insulating molded body containing a stacked compressed body and a cured inorganic binder.
The length and width of each of the heat insulating wall material samples 5 to 8 was about 100 mm×about 100 mm, and the thickness was 20 mm to 20.8 mm.
The initial weight (before water absorption) of the insulating wall material samples was 0.041 kg to 0.073 kg.
The densities of the insulating wall material samples ranged from 205 kg/m ³ to 347 kg/m ³ .
These insulating wall material samples were immersed in water in a bucket to absorb water (water absorption process). After these insulating wall material samples were substantially completely absorbed in the water absorption process for 1 hour (60 minutes), they were taken out of the bucket and immediately weighed, which was 0.220 kg to 0.244 kg.
The removed heat insulating wall material sample was left to stand in an environment at a temperature of 20° C. to 30° C. and a relative humidity of 60% RH to 80% RH to dehydrate.
As shown in Table 2, the weight of the insulating wall material sample 25 hours after removal (at the end of the water absorption step) was 0.197 kg to 0.221 kg, and the weight loss rate was 9% to 10%.

[Comparative Example]
As a comparative example, a thermal insulation wall material sample made of calcium silicate was prepared. The length and width of the thermal insulation wall material sample made of calcium silicate was 99 mm x 99 mm, the thickness was 26.3 mm, and the density was 440 kg/ ^m3 . When the dehydration of the thermal insulation wall material sample made of calcium silicate was examined under the same conditions as in Example 2, the weight loss rate was 6%.
It has been confirmed that the insulating wall material according to the present invention is lighter in weight and has superior dewatering properties than insulating wall materials made of calcium silicate.

The present invention can be applied to ventilation ducts such as kitchen exhaust ducts, air conditioning ducts, and chimneys in buildings, for example.

Reference Signs List 1: Building ventilation duct 2: Insulating wall material 2a: Glass fiber 4: Surface sheet 10: Insulating molded body 11: Stacked compressed body 11a: Defibrated body 11x: Stacked body 12: Inorganic binder hardened body 12a: Inorganic binder 13: Stripe-like portion

Claims (2)

A heat insulating wall material for ventilation ducts in a ventilation duct of a building,
a heat insulating shaped body formed into a predetermined wall shape along a flow path of the ventilation duct, the heat insulating shaped body including a stacked compressed body in which defibrated glass fiber bodies are stacked and compressed, and a cured inorganic binder that is diffused in the stacked compressed body and bonds the defibrated bodies together,
The density of the stacked compressed body in the heat insulating molded body is more than 250 kg/ ^m3 and 370 kg/ ^m3 or less,
The insulating wall material for ventilation ducts is characterized in that when both sides of the insulating wall material for ventilation ducts are sandwiched between backing plates, a bolt is inserted through the insulating wall material and a tightening torque of 20 Nm is applied, the degree of thickness reduction is 50% or less. A heat insulating wall material for ventilation ducts in a ventilation duct of a building,
a heat insulating shaped body formed into a predetermined wall shape along a flow path of the ventilation duct, the heat insulating shaped body including a stacked compressed body in which defibrated glass fiber bodies are stacked and compressed, and a cured inorganic binder that is diffused in the stacked compressed body and bonds the defibrated bodies together,
The density of the stacked compressed body in the heat insulating molded body is more than 250 kg/ ^m3 and 370 kg/ ^m3 or less,
The insulating wall material for ventilation ducts is characterized in that the weight loss ratio after 25 hours from the start of dehydration after water absorption, relative to the weight when the insulating wall material for ventilation ducts has substantially completely absorbed water, is 9% or more at a temperature of 20°C to 30°C and a relative humidity of 60% RH to 80% RH.

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