JP2003113565A - Formed glassfiber article and forming method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a formed glassfiber article suitable for the use at a high temperature, keeping the flexibility of the constituent fiber and relatively easily formable to a complicate form at a low cost and provide a method for forming the article. SOLUTION: A core material 11 for vacuum insulation use consisting of a formed glassfiber article is produced by a process comprising an attaching step to immerse a needle mat 1 obtained by the needling of glassfibers in an aqueous solution of a silica sol 2 and squeeze the mat with a roller 4, a compression-molding step to place the mat between a pair of upper and lower heated plates 5 of a hot press and bond the fibers with an inorganic binder attached to the glassfibers to form a compression-molded plate, a welding step to heat the formed needle mat 1 in an electric oven 8 and keep the mat at a temperature lower than the softening point of the glassfiber to weld the glass fiber to the inorganic binder or weld the contact point of the glassfibers with each other and a solidifying step to take the needle mat 1 out of the electric oven 8 and spontaneously cool the mat to solidify the bonded points.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a glass fiber molded article and a method for molding the same.

[0002]

2. Description of the Related Art There are the following methods for molding molded articles such as mats, boards and papers from glass fibers. Felt molding: A method in which short glass fibers are bonded and bonded with a binder to form a felt mat. Needling: A method in which long glass fibers are entangled with each other by needle punching and bonded to each other to form a slightly compressed mat. The surface may be coated with a binder. Papermaking: A method in which glass fibers are put into a binder-added water to form a slurry, and the slurry is scooped up so as to make paper and then dried, and the glass fibers are bonded and bonded with a binder. Each binder used in the above ~, starch-based,
Organic binders such as silicone and rubber are common,
The organic binder may be mixed with an inorganic binder such as silica.

An example of using a glass fiber molded product obtained by hardening a glass fiber material with an inorganic binder is an adsorbent attached to the glass fiber molded product hardened with the inorganic binder and at least one metal foil for sealing them. There is a heat insulation panel provided with the laminated film which has (JP-A-63-18).
7084).

Further, as a method having an effect of adhering glass fibers to each other, there is a vacuum heat insulating material in which inorganic fibers are treated with an acid to bond each contact point with a component eluted from the fibers (Japanese Patent Laid-Open No. 7- 167376).

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Needling and papermaking have advantages and disadvantages as summarized in Table 1 below, and they are applied to applications making use of their respective advantages. However, the molded product is suitable for high temperature use,
In addition, there has been no molding method that facilitates molding into various shapes and increases the strength of the molded product. That is,
Felt molding and papermaking require an organic binder. Therefore, when the molded product is used at high temperature, smoke is generated due to decomposition of the organic binder, or the binding force due to the organic binder is lost to lose heat resistance. However, there is a problem that the degree of vacuum is lowered due to vaporization of the organic binder and the heat insulation performance is deteriorated, and it is not suitable for high temperature use. On the other hand, since the needling does not require a binder, this problem does not occur unless the binder is coated, but it is possible to mold only a simple plate-like mat, or because it is a connection by a discrete needling point. There was a problem that it was difficult to increase the strength.

When an inorganic binder is used, it is necessary to maintain the high heat insulation performance because the inorganic binder is pulverized and scatters in the portion where the coating material is sealed, the sealing is incomplete and the degree of vacuum is lowered. There is a problem that there is a risk of hindering the perfect sealing. Further, silica sol is used as the inorganic binder,
Although there are cement type and the like, there is a problem that the pressure resistance is inferior as compared with the organic binder.

Furthermore, with the binding force of only the inorganic binder,
0.1 MPa (1.02 kg / cm ^Two) Compressibility under pressure
Of less than 10% requires an increase in bulk density,
Rate and vacuum deaeration will be reduced. Also, the compression rate is 1
If it exceeds 0%, put it in a heat-insulating container or bag as a core material and vacuum.
When evacuated, the vacuum force may cause the heat insulating container or bag to dent significantly.
Have problems.

Further, the method of binding glass fibers to each other by acid treatment has a problem that the acid component is likely to remain in the binding portion, the coating material such as stainless steel is likely to be corroded and deteriorated, and the environment is polluted. .

An object of the present invention is to solve the above-mentioned problems, to make molded articles suitable for high temperature use, to maintain the flexibility of fibers, and to relatively easily and inexpensively form a glass fiber molded article and a molding method thereof. Is to provide.

[0010]

In order to achieve the above object, the glass fiber molded article of the present invention has a glass fiber formed into a desired compressed shape with fixation between the fibers by an inorganic binder adhered to the glass fiber. While being compression-molded, the glass fiber and the inorganic binder and the contact points between the glass fibers are fused at a temperature lower than the softening point of the glass.

Further, the method for molding a glass fiber molded article of the present invention comprises a step of adhering an inorganic binder to the glass fiber and a step of compressing the glass fiber into a desired compressed shape so that the inorganic binder adhered to the glass fiber is A compression molding step of maintaining a compressed shape by fixing the fibers, and a temperature of the glass fiber lower than the softening point of the glass fiber by 10 to 100 ° C. to maintain the glass fiber and the inorganic binder. The present invention is characterized by including a fusing step of fusing the spaces and the contact points of the glass fibers with each other, and a solidifying step of cooling the glass fibers to solidify the fusing.

The type of glass constituting the glass fiber is not particularly limited, but A glass, C glass, E glass, T
Glass etc. can be illustrated. In addition to glass fibers, heat-resistant inorganic fibers other than glass fibers (alumina fibers, ceramic fibers, silica fibers, rock wool, etc.) or heat-resistant metal fibers (stainless steel, chromium-nickel alloys, high nickel alloys, high cobalt alloys) Fibers) can also be mixed. The fiber diameter of the glass fiber is not particularly limited, but 1 to
The thickness is preferably 30 μm, and although it depends on the degree of vacuum, the thinner it is, the lower the thermal conductivity is and the more excellent the heat insulating performance tends to be.

Examples of the inorganic binder include silica sol, alumina sol, titania sol, zirconia sol, water glass and the like. These may be mixed, or ceramic powder or low melting point glass may be added. When ceramic powder is added, titania and silicon nitride, which are powders having low solid thermal conductivity, are preferable. Further, in this case, the voids become small and the gas heat conduction is almost eliminated, so that the vacuum heat insulation performance is improved. On the other hand, when the ceramic powder is added, the number of heat transfer points of the object increases, and solid heat conduction in which heat is transferred through the powder increases, so that there is a problem that the vacuum heat insulation performance deteriorates. Therefore, when a glass fiber molded product to which ceramic powder is added is used as a core material for vacuum heat insulation, it is important to adjust the addition amount to maximize the reduction of contradictory heat conduction under the temperature conditions. Furthermore, an organic binder may be added as necessary to enhance the adhesion dispersibility and adhesion of the inorganic binder. The organic component is vaporized by the heat treatment in the subsequent step and can be eliminated.

The attaching step is not particularly limited, but a method of immersing a needle mat formed by needling glass fibers in an inorganic binder and squeezing with a roller can be exemplified. The compression molding step is not particularly limited, but a method of compressing the glass fiber with a heated sandwich plate can be exemplified.

The fusing step is not particularly limited, but the glass fibers fixed by an inorganic binder and compression-molded are removed from the sandwich plate, and the contact points between the glass fibers and the inorganic binder and between the glass fibers are heated by heating. A method of fusing can be exemplified. At this time, the glass fibers are protected from the external heat by the inorganic binder. The heating conditions are not limited, but in order to prevent fiber deterioration and maintain flexibility, it is preferable to perform fusion treatment at a temperature lower by 10 to 100 ° C. than the softening point and in a short time.

The above-mentioned temperature is defined as "temperature lower than the softening point by 10 to 100 ° C.", because at a temperature higher than the upper limit of this range, the glass fiber may be excessively melted and shrunk into a lump. This is because if the temperature is lower than the lower limit of the range, the viscosity of the glass fiber is too high and it becomes difficult to fuse.
More preferably, the temperature is 20 to 80 ° C. lower than the softening point, and further preferably 30 to 60 ° C. from the softening point.
The temperature is lower by ℃.

The "temperature lower than the softening point by 10 to 100 ° C." may be replaced with "the temperature at which the viscosity is 5 × 10 ⁷ P to 10 ⁹ P" from the viewpoint of the viscosity of the glass constituting the glass fiber. it can. This is because if the viscosity is lower than 5 × 10 ⁷ P, the glass fibers may be excessively melted and shrink into a lump, and if the viscosity is higher than 10 ⁹ P, it is difficult to fuse the glass fibers. More preferably, "the viscosity is 6 × 1
“Temperature at which 0 ⁷ P to ⁸ × 10 ⁸ P is obtained”, and more preferably “Temperature at which viscosity is 7 × 10 ⁷ P to 5 × 10 ⁸ P”.

Here, the mechanism of fusion bonding will be described by taking the contact points between the glass fibers and the inorganic binder and between the glass fibers as an example. Since glass fibers are amorphous, they do not have the melting point of crystalline substances, and when the temperature is raised, the viscosity continuously decreases with the migration of the primitive substances, and it shifts to a liquid. go. Generally, the softening point of glass refers to the temperature when the viscosity is 4.5 × 10 ⁷ P (log η = 7.65), which is the lower limit temperature at which the glass can be molded. The molding method of the present invention utilizes the continuously changing viscosity of glass as described above, and the glass has a viscosity of 4.5 × 10 ⁷
When the temperature is slightly lower than P, the phenomenon of fusion between the glass fiber and the inorganic binder and between the glass fibers at the contact points of each other is utilized, and surface fusion is performed to the extent that thermal degradation inside the fiber does not occur, It utilizes the phenomenon that a neck can be formed in a short time during the sintering process of ceramic powder. In fact, in theory, it seems that the molding of resin is closer to this mechanism than the sintering of ceramics. Further, since the fusion is point contact fusion, closed air bubbles are not left behind.

The time for holding at the temperature "10 to 100 ° C. lower than the softening point" or each temperature in the other range is
Depending on whether the temperature is high or low within the range, it is shortened when the temperature is high (for example, 1 to 20 minutes) and long when the temperature is low (for example, 15 to 50 minutes). In addition, the same time differs depending on the compression shape and size, and is made longer when, for example, the thickness is large and it is difficult to transfer heat to the inside.

The compressed shape is not particularly limited,
Forming into complicated shapes such as plate shape (including not only flat plate shape but also curved plate shape, corrugated plate shape, etc.), rod shape, block shape, box shape, tubular shape, etc., and further forming large irregularities on the surface An example is molding.

The glass fiber molded article is not particularly limited, but is often used because it has a bulk density of 250 to 480 kg / m ^3.
Then, it is preferable that the compressibility is 10% or less at a pressure of 0.1 MPa. The load of compression is not particularly limited and may be very light, but when molding a product having a high compression ratio and a high specific gravity (high density), it is necessary to increase the load.

Further, "compressing the glass fiber into a desired compressed shape" is preferably carried out prior to "holding at a temperature lower than the softening point by 10 to 100 ° C." or each temperature in the other range. .

The use of the glass fiber molded product obtained by the method for molding a glass fiber molded product is not particularly limited, but a vacuum heat insulating core material can be exemplified.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a vacuum heat insulating core material and a molding method thereof embodying the present invention will be described. Note that the materials, configurations, numerical values, etc. described in the embodiments are merely examples, and can be changed as appropriate. [Embodiment] (1) Adhesion step As shown in FIGS. 1A to 1C, a needle mat 1 (thickness 10 mm, fiber diameter 9 μm, bulk density 100 kg) formed by needling glass fibers made of E glass. / M ³ ,
Silica sol 2 (Snowtex ST20 manufactured by Nissan Chemical Industries, Ltd.) is diluted with the same weight of water 3 and the binder is not used. Then, it was squeezed by the roller 4.
The impregnating liquid amount was 5.5 kg / m ² , and the inorganic binder adhered to the glass fiber.

(2) Compression molding step Next, as shown in FIG. 2 (a), the glass fiber after drawing is sandwiched between both sandwiching plates 5 heated to 160 ° C., and a height of 4 mm is provided between the peripheral edges. The stopper 6 (metal gauge) was set. The stopper 6 regulates the reduction of the thickness and compresses into a desired compression shape. Eventually, the needle mat 1 was compressed to a thickness of 4 mm by compression (hot pressing) by the both sandwiched plates 5 and formed into a plate shape (FIG. 2B). FIG. 3 (a) is an enlarged schematic view of the joining of the glass fiber 14 and the silica sol 2 at this time.
Shown in. In this step, the silica sol 2 is powdered and solidified as the water content covering the entire glass fiber 14 is evaporated, so that the glass fiber 1 passes through the silica sol 2.
4 pieces were joined and compression molded.

(3) Fusing Step Next, as shown in FIG. 2 (c), the needle mat 1 formed by removing from both sandwiching plates 5 and fixing the inorganic binder is placed on the refractory 7. It is placed, placed in an electric furnace 8 and heated by a heater 9 and held at 780 ° C., which is 60 ° C. lower than the softening point 840 ° C. of the E glass fiber, for 30 minutes, so that the space between the glass fiber and the silica sol of the inorganic binder or the glass fibers Of the contact points were fused. Glass fiber 1 at this time
3 (b) is an enlarged schematic view of the fused portion 15 between the glass sol 2 and the silica sol 2 and between the glass fibers 14.

(4) Solidifying Step After the above-mentioned holding for 30 minutes, the needle mat 1 was taken out from the electric furnace 8 and naturally cooled at room temperature to solidify the fusion. The thickness was 4 mm and the bulk density was 380 kg / m
No. ³ vacuum insulation core material was molded. This is because the silica sol solid content is 130 kg in 250 kg / m ^{3 of} glass fiber.
/ M ³ means that it was added.

When this molded product was evaluated, the average fiber diameter was 9 μm, the fiber length was 10 to 30 mm, the loss on ignition was 0.1% or less, and the compressibility was 0.10 MPa (1.02 kg / c).
m ² ) is 10% or less, and the tensile strength is 12 kgf / c.
It was m ² . In addition, there is no decrease in tensile strength in the air atmosphere at 500 ° C., and the pressure is 0.1 MPa (1.02 kg / cm ² ).
The compression recovery property by pressurization was 100% and remained unchanged.

As shown in FIG. 2D, the vacuum heat insulating core material 11 is sandwiched between two covering materials 10 from both sides in the length direction of the molded vacuum heat insulating core material 11 for vacuum heat insulating. The peripheral portions of the coating materials 10 were bonded with a sealing material so as to cover the peripheral end surface 12 of the core material 11 to form a vacuum heat insulating material 13.

The material of the sandwich plate 5 is not limited to stainless steel, but may be ceramics (alumina, SiC, etc.).
Etc.) When the area of the sandwich plate 5 is small, the degree of freedom of the material is high, but when the area of the sandwich plate 5 is large,
In stainless steel, warpage due to thermal expansion occurs and it becomes difficult to form, and thus ceramics that are less problematic are preferable.

As the temperature condition in this embodiment, it is preferable to maintain the temperature at a temperature 30 to 60 ° C. lower than the softening point 840 ° C. of E glass for 10 to 30 minutes. Eg 8
If the substrate is held at 10 ° C. for a long time, the board thickness may be less than the height of the stopper 6, so that the temperature and the holding time corresponding to each required size are required. In addition, for example, in the case of glass fiber made of C glass, a temperature 30 to 60 ° C. lower than the softening point 760 ° C. (eg 70
It is preferable to hold at 0 ° C. for 10 to 30 minutes.

[Comparative Example 1] Example in which the fusion process and the solidification process performed in the embodiment are not performed (1) Adhesion process E Needle mat formed by needling glass fibers made of glass (thickness 10 mm, fiber 9 μm, density 100
Silica sol (Snowtex ST20 manufactured by NISSAN CHEMICAL INDUSTRIES CO., LTD.) was diluted with kg / m ^{3 of} the binder (no binder), and was dipped and then squeezed with a roller to obtain an impregnating liquid amount of 5.5 kg / m ^2, and the inorganic binder are adhered to the glass fiber.

(2) Compression molding step The glass fibers after drawing were placed on both sandwich plates heated to 160 ° C., and a stopper (metal gauge) having a height of 4 mm was set between the peripheral edges. By pressing for approximately 5 minutes, a molded body having a thickness of 4 mm and a bulk density of 380 kg / m ³ was obtained. Here, for comparison with the example, the heat treatment is not performed. When this molded product was evaluated, the average fiber diameter was 9 μm, the fiber length was 10 to 30 mm, the loss on ignition was 0.5%, and the compression rate was 0.10 MPa (1.02 kg / c).
m ² ), and the tensile strength was 8 kgf / cm ² .

As in Comparative Example 1, without heat treatment,
1 at a compression rate of 0.10 MPa (1.02 kg / cm ² ).
In order to achieve 0% or less, it is necessary to increase the bulk density to 500 kg / m ³ or more. In this case, the thermal conductivity and the vacuum degassing property were deteriorated, so that the heat insulating effect was deteriorated, and the flexibility of the fiber was restricted, and the compression recovery property tended to be impaired.

[Comparative Example 2] Example in which the attaching step and the compression molding step included in the example are not performed (1) Fusing step / solidifying step E Needle mat formed by needling glass fiber made of glass (thickness: 12 mm , Fiber 9 μm, bulk density 10
A mat of 0 kg / m ³ , no binder is installed between both sandwich plates (stainless steel plate (thickness 2 mm, SUS304)), and a stopper (SUS3) with a height of 4 mm is provided between the peripheral edges.
04) was set.

While the needle mat was sandwiched between both sandwich plates, it was heated in an electric furnace at 780 ° C. for 30 minutes and then cooled and solidified to obtain a thickness of 4 mm and a bulk density of 319 kg / m.
A molded product of ³ (linear shrinkage in the plane direction of about 3% occurred) was obtained. When this molded product was evaluated, the average fiber diameter was 9 μm, the fiber length was 10 to 30 mm, the loss on ignition was 0.1% or less, and the compression rate was 5% at 0.10 MPa (1.02 kg / cm ² ). It was

In the method of Comparative Example 2, even the fibers inside were prone to thermal deterioration, and there was a tendency to slightly impair the compression recovery property. In addition, it is difficult to form a complex shape such as a box shape or a tubular shape, or to form large irregularities on the surface.

"Inorganic binder fusion molding" is a method of fixing with an inorganic binder and then fusion molding as described in the present invention, and "papermaking" is a molding method of Comparative Example 1 in which only an inorganic binder is molded. The molding method like Comparative Example 2 which does not use the inorganic binder is referred to as "fusion molding", and its advantages and disadvantages are summarized in Table 1 below in comparison with the conventional molding methods.

[0039]

[Table 1]

Here, the "simple shape" refers to the ease of forming into a simple shape such as a plate shape, a rod shape, or a block shape, and the "complex shape" refers to forming into a complicated shape such as a box shape or a tubular shape. Says the ease. Further, the "heat resistance" does not mean the heat resistance of the glass fiber itself, but the heat resistance of a molded product obtained by integrating the glass fiber and other materials. In the case of glass fibers to which organic matter such as resin needs to be added, the heat resistance of the organic matter determines the heat resistance of the molded product.

The advantages of the inorganic binder fusion molding are as follows. Due to the fusion of the surface layer by heat treatment, the flexibility of the fibers inside is maintained, and the compression recovery is not impaired. A large (large-area) board can be made relatively easily with a jig. Since it does not contain organic matter at all, no smoke is emitted during high temperature use, and therefore vacuum deterioration does not occur for a long time when used in a vacuum state. The softness and specific gravity (bulk density) of the surface can be easily changed by setting the conditions. There is no powdery surface when molded with only an inorganic binder. It is relatively easy to form a complex shape such as a box shape or a tubular shape, or to form large irregularities on the surface.

The use of the glass fiber molded body obtained by the fusion molding of the inorganic binder is not particularly limited, but it is suitable for a heat insulating material (in particular, a heat insulating core material) used in various heat insulating containers, various heat appliances and the like. At present, the heat insulating core material of the vacuum heat insulating container to be used at around 400 ° C and the vacuum heat insulating core material to be used at -20 to 80 ° C (for example, the vacuum heat insulating core material of a thermos bottle) are planned. It is an application that makes full use of the advantage of. In addition, it is suitable for applications in which a calcareous board or a ceramic board is used and up to about 500 ° C.

The present invention is not limited to the configuration of the above-described embodiment, and may be embodied with appropriate modifications, for example, as follows, without departing from the spirit of the invention. (1) The number of the needle mats 1 should be one, or the number of layers should be two or four or more. (2) To stack different types of needle mats 1. (3) Forming a box by combining two shaped bodies with a U-shaped cross section.

[0044]

As described above in detail, according to the glass fiber molded product and the molding method thereof according to the present invention, the molded product is suitable for high temperature use, the flexibility of the fiber is maintained, and the complex shape is comparatively formed. It has an excellent effect that it can be made easily and inexpensively.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing (a) a needle mat, (b) an inorganic binder treatment, and (c) a roller squeeze after an inorganic binder treatment according to an embodiment of the present invention.

FIG. 2 is (a), (b) both sandwich plate usage diagrams, (c) electric furnace installation diagram, and (d) an explanatory diagram showing a vacuum heat insulating core material according to the embodiment.

3A and 3B are enlarged schematic diagrams of the joining of the glass fiber and the inorganic binder according to the same embodiment, and FIG. 3B is an enlarged schematic diagram of the joining of the glass fiber and the inorganic binder after fusion.

[Explanation of symbols]

1 Needle mat 2 Silica sol 5 sandwich plate 8 electric furnace 11 Vacuum insulation core material 14 glass fiber 15 Fusion part

Claims (9)

[Claims] 1. A glass fiber is compression-molded into a desired compression shape with fixation between fibers by an inorganic binder adhered to the glass fiber, and the glass fiber is sandwiched between the inorganic fiber and the glass fiber. A glass fiber molded product obtained by fusing at a contact point of less than the softening point of glass. 2. An adhering step of adhering an inorganic binder to glass fibers, compressing the glass fibers into a desired compressed shape, and the inorganic binder adhered to the glass fibers holds the compressed shape by fixing the fibers together. By a compression molding step and maintaining the glass fiber at a temperature lower than the softening point of the glass fiber by 10 to 100 ° C., the contact points between the glass fiber and the inorganic binder and the contact points between the glass fibers are fused to each other. A method for molding a glass fiber molded article, which includes a fusion step of: and a solidification step of solidifying the fusion by cooling the glass fiber. 3. An adhering step of adhering an inorganic binder to glass fibers, and compressing the glass fibers into a desired compression shape, and the inorganic binder adhering to the glass fibers fixes the fibers to maintain the compression shape. By the compression molding step and maintaining the glass fiber at a temperature at which the viscosity becomes 5 × 10 ⁷ P to 10 ⁹ P, the contact points between the glass fiber and the inorganic binder and the contact points between the glass fibers are fused. Fusing process to
A method of molding a glass fiber molded article, which includes a solidifying step of solidifying the fusion by cooling the glass fiber. 4. The method for molding a glass fiber molded article according to claim 2, wherein in the attaching step, the glass fiber is immersed in an inorganic binder and squeezed. 5. The method for molding a glass fiber molded article according to claim 2, wherein in the compression molding step, the glass fiber is compressed by a sandwich plate that is heated. 6. The method for molding a glass fiber molded article according to claim 2, wherein the fusion bonding step is carried out by removing the glass fiber fixed by the inorganic binder and compression molded from the sandwich plate. 7. The method for molding a glass fiber molded product according to claim 1 or a glass fiber molded product according to claim 2 or 3, wherein the glass fiber is a needle mat formed by needling glass fiber. 8. The glass fiber molded article has a bulk density of 25.
0-480kg / m ^ThreeThen, compressibility at 0.1 MPa pressurization
Is less than or equal to 10%.
Lath fiber molded product or glass fiber according to claim 2 or 3.
Molding method for molded products. 9. The glass fiber molded product according to claim 1, or the glass fiber molded product according to claim 2 or 3, wherein the glass fiber molded product is a vacuum heat insulating core material.