JPH07331572A - Low-density laminated thermal insulation material and its production - Google Patents

Abstract

PURPOSE:To obtain the low-density, lightweight thermal insulation material improved in thermal insulation capability and applicability, and high in compressive resilience and vibration durability. CONSTITUTION:A crimped fiber-contg. cotton-like fibrous sheet with carbon fibers accounting for 50-100wt.% of the total fibers is horizontally folded in several layers, and at least the respective layers of the resultant laminate adjacent to each other are mutually jointed with a binder such as a thermosetting resin into a unified form, thus obtaining the objective low-density laminated thermal insulation material 5-20kg/m<3> in bulk density. For the above carbon fibers, carbonized pitch-based carbon fibers etc., can be used, and the cotton-like fibrous sheet can be laminated in >=5 layers. The content of the binder stands at 5-20wt.% of the whole thermal insulation material. This thermal insulation material may be obtained by either of the following two alternative processes: (1) the laminate is impregnated with the binder followed by heat molding; and (2) both sides of the cotton-like fibrous sheet 1 are sprayed with a resin liquor from a nozzle 15 and the sheet is folded into a laminate 7 which is then subjected to heat molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-density laminated heat insulating material which is lightweight, non-combustible or flame-retardant and useful as a heat insulating material for high-speed moving bodies, and a method for producing the same.

[0002]

2. Description of the Related Art As a heat insulating material, a sound absorbing heat insulating material using glass fiber is widely used. However, since the specific gravity of glass fiber is large, it is necessary to use a large amount of glass fiber in order to ensure the same heat insulation performance. Therefore, the weight of the heat insulating material is large and it is difficult to reduce the weight. Further, if the glass fiber is exposed on the surface of the heat insulating material, a tingling sensation is given and workability at the site is deteriorated. Therefore, it is necessary to cover the surface and the end surface of the heat insulating material with aluminum foil or the like. Furthermore, in the unlikely event of a fire, the glass fiber melts, making it impossible to maintain its function as a heat insulating material.

In order to solve such problems, it has been proposed to use carbonaceous fibers instead of glass fibers. For example, in Japanese Examined Patent Publication No. 3-13349 and Japanese Examined Patent Publication No. 3-17946, a soundproof heat insulating material constituted by batting of non-graphite carbon fiber in a coil shape or a stretchable non-graphite carbon fiber is used. Is disclosed. Since this soundproof heat insulating material is made of batting, the compression repulsion force and the restoring property in the thickness direction are still insufficient. Further, the coil-shaped or non-linear non-graphitic carbon fiber needs to be prepared by once knitting a polyacrylonitrile fiber into a cloth, heating and heat-setting, and then again unraveling the cloth. .

Japanese Patent Laid-Open No. 3-279454 discloses a sheet-like heat insulating and sound absorbing material in which inorganic short fibers such as carbon fibers are accumulated in order to reduce the possibility of delamination and to enhance the compressibility and flexibility in the surface direction. Disclosed is a heat-insulating sound-absorbing material which is zigzag-folded in the vertical direction (thickness direction) with respect to the horizontal direction, and fibers are bonded to each other by a binder to be integrally formed as a whole. However, when such a heat insulating and sound absorbing material is used as a heat insulating material, the fold direction of the sheet-like heat insulating and sound absorbing material and the orientation direction of the fibers are parallel to the heat flow direction in the arranged state of the heat insulating material. The conductivity is increased by a factor of 2 to 3 and the heat insulation performance is reduced. Further, in order to maintain the shape, many binders are required, and the sheet-like heat insulating and sound absorbing material is folded in the thickness direction of the heat insulating material. Therefore, it is difficult to obtain a thin, low-density, lightweight heat insulating material, which impairs its use as a heat insulating material for a high-speed moving body or the like that is required to be lightweight.

[0005]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a low-density, lightweight heat insulating material having high resilience, compression repulsion and vibration durability, and a method for manufacturing the same.

Another object of the present invention is non-combustible or flame retardant,
It is an object of the present invention to provide a low-density laminated heat insulating material having excellent workability and heat resistance and high heat insulating properties, and a method for producing the same.

Still another object of the present invention is to provide a low density laminated heat insulating material which is useful as a sound absorbing heat insulating material for a high speed moving body which is required to be lightweight, and a method for producing the same.

[0008]

Means for Solving the Problems As a result of earnest studies for achieving the above-mentioned object, the present inventor has found a cotton-like fiber sheet containing crimped fibers and having a specific amount of the entire fibers composed of carbonaceous fibers. When stacked vertically while rocking and integrated with a thermosetting resin, it is possible to obtain a low-density, lightweight laminate having high resilience, compression repulsion, and vibration durability. The present invention has been completed by discovering that the cotton-like fiber sheet can be oriented in a direction (shielding direction) substantially orthogonal to the heat transfer direction by arranging it in order to improve the heat insulating property.

That is, the low density laminated heat insulating material of the present invention is
A laminated body in which cotton-like fiber sheets containing crimped fibers and 50 to 100% by weight of the entire fibers are composed of carbonaceous fibers are laminated in a plurality of layers in the thickness direction, and at least each layer of the laminated body is joined. It has a bulk density of 5 to 20 kg / m ³ . The cotton-like fibrous sheet may be composed of crimped carbonaceous fibers alone, or may be used in combination with other fibers. The cotton fiber sheet often contains 50% by weight or more of carbonized carbon fibers. In many cases, the thickness of the cotton-like fiber sheet is about 0.1 to 20 mm and the number of folds is 5 or more. Further, a thermosetting resin can be used as the binder.

The low-density laminated heat insulating material is (1) a method in which the cotton-like fiber sheet is laterally folded to be laminated in a plurality of layers, and the obtained laminated body is impregnated with a binder, and molded.
(2) It can be produced by a method of spraying a binder on both sides of the cotton-like fiber sheet, stacking the cotton-like fiber sheet in a plurality of layers while folding the cotton-like fiber sheet in the lateral direction, and molding the obtained laminate. .

The present invention will be described in more detail below.

[0012] The cotton-like fiber sheet contains at least crimped fibers in order to improve the restorability, compression repulsion and vibration durability and to obtain a low-density and lightweight heat insulating material. The crimped fibers may be carbonaceous fibers or non-carbonaceous fibers. When such crimped fibers are included, the cotton-like fiber sheet has a three-dimensional network structure and low bulk density. In addition,
The crimped fiber can be produced by a conventional method, and the carbonaceous crimped fiber can be produced by spinning using, for example, a vortex method (Japanese Patent Publication No. 58-057374).

The cotton-like fiber sheet is made up of 50 to 10 fibers.
0% by weight is composed of carbonaceous fibers. The carbonaceous fiber may be a crimped fiber or a straight non-crimped fiber. The carbonaceous fibers include, for example, carbon fibers which are carbonized or graphitized from polyacrylonitrile, phenol resin, polymer such as rayon, pitch such as coal pitch and petroleum pitch as raw materials. In addition, carbonization means, for example, firing treatment at a temperature of about 450 to 1500 ° C., unless otherwise specified. What is "graphitization"?
Unless otherwise specified, for example, it means firing at a temperature of about 1500 to 3000 ° C., and the case where the crystal structure is not a graphite structure is also included in the concept of graphitization.

The carbonaceous fiber is a graphitized fiber (for example, 15
The carbon fiber may be carbon fiber fired at about 00 to 3000 ° C.), but carbonized fiber is preferable from the viewpoint of folding processability. Carbonized fiber has a firing temperature of 450 to 1500 ° C.
(For example, 500 to 1300 ° C.), preferably 600 to
The carbon fiber is preferably fired at 1200 ° C, more preferably 700 to 900 ° C. Firing temperature is 450
Below ℃, in the case of polyacrylonitrile-based carbon fiber,
Toxic HCN gas and NH ₃ gas may be generated during heating due to fire, and other fibers (eg pitch-based carbon fiber) may have poor fiber processability such as processability into a cotton fiber sheet. easy. On the other hand, when the temperature exceeds 1500 ° C., the cost becomes high and the firing yield is lowered, which is not economical, and the fiber is liable to be brittle in terms of workability. If pitch-based carbon fiber is used,
Unlike the flame-resistant polyacrylonitrile fiber, HCN gas and NH ₃ gas are not generated by heating,
The safety can be improved.

The cotton-like fiber sheet contains crimped fibers,
In addition, it is sufficient that the specific amount of the entire fiber is composed of carbonaceous fiber. When the crimped fibers are carbonaceous fibers, the cotton-like fiber sheet may be composed of the crimped carbonaceous fibers alone, but other fibers (other crimped fibers, non-crimped fibers) The carbonaceous fiber or the non-crimped non-carbonaceous fiber) can also be used in combination. Other fibers include various non-combustible or flame-retardant fibers such as inorganic fibers (eg, glass fibers;
Ceramic fiber such as aluminum silicate fiber, alumina fiber, silicon carbide fiber; mineral fiber such as asbestos and rock wool; metal fiber such as stainless steel; non-crimped carbon fiber made of the same material as the carbon fiber Etc.), organic fibers (for example, viscose rayon, rayon fibers such as cupra, acetate fibers, thermosetting resin fibers (for example, phenol resin fibers such as novoloid fibers), nylon fibers, flame-retardant polyester fibers, polyvinyl alcohol Examples thereof include synthetic fibers (vinylon fibers), polyether sulfone fibers, polymer fibers such as aromatic polyamide fibers (aramid fibers, etc.), and the like. At least one of these fibers can be used.

Preferred non-combustible or flame-retardant fibers include organic fibers to reduce the bulk density of the insulation. In order to suppress the increase in bulk density, ceramic fibers,
When using inorganic fibers such as mineral fibers and metal fibers, the amount of inorganic fibers used is often small. The other fibers may be crimped fibers or linear non-crimped fibers.

The crimp degree in the crimped fiber may be within a range that does not impair the resilience, resilience and vibration durability of the heat insulating material, and is, for example, about 0.5 to 5 times per 10 mm. The fiber diameter of the crimped fiber and the non-crimped fiber is, for example, 4 to 30.
It is about μm, and often about 7 to 20 μm.

Crimped fibers and non-crimped fibers are often used as short fibers, and their fiber length is in a non-stretched state,
For example, 0.1 to 10 cm, preferably 0.5 to 8 cm
The fiber length is often about 1 to 5 cm.
When the fiber length is less than 0.1 cm, the three-dimensional network structure of the cotton-like fiber sheet cannot be maintained, and it is difficult to obtain a low-density heat insulating material. When the fiber length exceeds 10 cm, the three-dimensional network structure is insufficient, It is difficult to increase the bulk.

The ratio of crimped fibers to non-crimped fibers can be selected within a wide range as long as the characteristics of the heat insulating material are not deteriorated, and for example, 50 to 100% by weight of crimped fibers (preferably 60 to 1).
00% by weight) and non-crimped fibers are 0 to 50% by weight (preferably 0 to 40% by weight). When the content of the crimped fiber is less than 50% by weight, it is often difficult to form a fiber sheet having a three-dimensional network structure, and the bulkiness due to folding is decreased, and the repulsion property of the heat insulating material is reduced.・ Vibration durability often decreases.

The ratio of carbonaceous fibers to non-carbonaceous fibers can be selected within a wide range as long as the heat insulating property is not deteriorated. For example, carbonaceous fibers of 50 to 100% by weight (preferably 60 to 100% by weight) and The non-carbonaceous fiber is about 0 to 50% by weight (preferably 0 to 40% by weight). When the content of the carbonaceous fiber is less than 50% by weight, it becomes difficult to maintain the shape of the heat insulating material when the glass fiber or the organic fiber is melted or disappears.

When a cotton-like fiber sheet is made of such a mixed fiber, even if the glass fiber or the organic fiber is melted or disappears, the carbonaceous fiber contained as the main component remains while maintaining its shape. The shape of the heat insulating material can be maintained. In addition, the bulk density of the heat insulating material is reduced, and the compression resilience
In order to improve vibration durability, shape retention, and the like, in the preferred cotton-like fiber sheet, the carbonaceous fibers are crimped carbonaceous fibers.

The thickness of the cotton-like fiber sheet can be selected according to the number of folds, the thickness of the molded heat insulating material, and the like.
-20 mm, preferably 0.5-15 mm, more preferably 1-10 mm. The bulk density of the cotton-like fiber sheet may be selected resilience of the insulation, and compression resilience in a range not impaired, for example, 0.1~15kg / m ^3,
It is preferably about 0.5 to 10 kg / m ³ , and often has a bulk density of about 1 to 7 kg / m ³ .

The cotton-like fiber sheets are folded to be laminated in a plurality of layers in the thickness direction of the heat insulating material (horizontal direction to the surface direction) to form a laminated body. That is, a laminated body is formed by vertically stacking cotton-like fiber sheets and stacking them. Number of folds of cotton-like fiber sheet (number of layers)
Can be selected according to the heat insulating property, the resilience, the resilience of the heat insulating material, and is, for example, 5 layers or more, preferably 7 to 100 layers, more preferably about 7 to 70 layers, and about 10 to 50 layers. Often there is. When the number of layers of the cotton-like fiber sheet is less than 5, the repulsion at the time of construction, vibration durability, etc. are reduced,
Adhesion to the heat-insulated site may be reduced and a gap may be generated. Probably because the fibers are oriented in the direction orthogonal to the laminated surface due to the folding and the orientation direction is maintained even after heat curing, a heat insulating material having high compression repulsion and vibration durability during construction can be obtained.

At least each layer of the laminate (that is, between the folding surfaces of the cotton-like fiber sheet) is joined by a binder. As the binder, an inorganic binder or an inorganic adhesive can be used, but an organic binder (organic adhesive) is often used. As the organic binder, thermosetting resins such as epoxy resin, phenol resin, vinyl ester resin, unsaturated polyester resin, thermosetting acrylic resin, polyurethane resin, and polyimide; polyvinyl acetate, ethylene-vinyl acetate copolymer, Examples include acrylic adhesives, thermoplastic resins such as polyamide, polyester, and polyacetal; and rubber adhesives such as butyl rubber and silicone rubber. The above resins are used alone or in combination of two or more.

Preferred organic binders include thermosetting resins having high heat resistance, particularly epoxy resins, vinyl ester resins,
Includes phenolic resins and the like. When a thermosetting resin is used, a curing agent depending on the type of resin can be used.

In the laminate, it is sufficient that at least the layers are bonded with the binder, and the layers are often bonded by the binder near the surface of the layers or the binder impregnated in the entire layers. The layers of the laminate may be joined together by a binder impregnated in the cotton fiber sheet.
The content of the binder is within a range that does not impair the integrity of the heat insulating material,
It can be appropriately selected according to the bulk density of the heat insulating material, for example,
5 to 20% by weight, preferably 7-1, of the total heat insulating material
It is about 8% by weight, more preferably about 8 to 15% by weight. In addition, each layer in the vertical direction adjacent to each other in the laminate is
Compressed in the process of molding into a predetermined shape such as pressure heat molding,
In many cases, they are in close contact.

Such a laminated heat insulating material is characterized by having a low density. For example, the heat insulating material has a bulk density of 5 to
20 kg / m ^3, preferably 8~18kg / m ^3, more preferably 10~16kg / m ³ approximately, 8-2
It is often about 0 kg / m ³ .

Further, the laminated heat insulating material has a low density and has a high tensile strength in the thickness direction even though the fiber sheets are laminated in the thickness direction. For example, the tensile strength in the thickness direction of the heat insulating material is 5 to 20 g /
It is about cm ² , preferably about 8 to 17 g / cm ² , and more preferably about 10 to 15 g / cm ² . Since it has such a tensile strength while having a low density, the heat insulating material has high integrity. Therefore, by interposing a heat insulating material in the heat-insulated portion of the railway vehicle, it is possible to prevent the displacement and the drop from the heat-insulated portion in combination with the high resilience and the compression resilience.
The tensile strength in the thickness direction is obtained by joining both side surfaces (fiber sheet surface) in the thickness direction of the heat insulating material to the adherend with an adhesive, and applying an external force in the tensile direction to the heat insulating material by the adherent, It means the strength at which the heat insulating material breaks (peeling strength).

Since such a heat insulating material has a low bulk density, it is lightweight and has a high compression resilience due to its resilience and cushioning property, and when it is interposed or interposed in the heat insulating portion, it adheres to the heat insulating portion. . Therefore, it is possible to bring the heat-insulated portion into close contact with the heat-insulated portion only by interposing or interposing a heat insulating material between the heat-insulated portion, which makes it possible to enhance the workability at the site and also to prevent the heat-insulated portion from being vibrated from the outside. It is possible to maintain high adhesion with and prevent misalignment, and high vibration durability. Further, when the heat insulating material is disposed in the heat insulating portion, since the cotton-like fiber sheets are laminated in the thickness direction, each fiber sheet extends in the direction orthogonal to the heat transfer direction. Therefore, the heat shielding effect and the heat insulating property are high. Furthermore, it is highly nonflammable or flame retardant, has high heat resistance, can suppress the generation of toxic gases, and is highly safe.

The heat insulating material of the present invention can be used in various ways, for example,
It can be manufactured by going through a step of laminating the cotton-like fiber sheet containing crimped fibers in a plurality of layers while laterally folding, and a step of integrally molding the obtained laminate with a binder.

More specifically, in the method for producing a heat insulating material, (1) a step of laminating a cotton-like fiber sheet containing crimped fibers in a plurality of layers while laterally folding it, and A method including an impregnation step of impregnating a binder and a step of forming a laminate impregnated with the binder is included.

The cotton-like fiber sheet is formed by opening the fibers made of crimped carbonaceous fibers by an opening means such as an opening machine, and then opening the sheet web by a carding means such as a card machine. Can be prepared by forming The orientation of the fibers in the sheet web is not particularly limited. For example, the sheet-shaped web is not limited to the card machine, but may be a random web having no fiber orientation, which is prepared by blowing fibers with an air stream and depositing them on a rotating perforated cylinder. .

In the laminating step, in the process of continuously supplying the cotton-like fiber sheet from the upper side to the lower side to the mounting table, the conveyor, etc., the fibers are folded by reciprocating in the thickness direction (lateral direction). The sheets can be stacked successively. When folded on the conveyor, the speed of the conveyor is lower than the supply speed of the fiber sheet.

The laminate may be subjected to the impregnation step as it is, but it is usually cut with a cutter into a predetermined shape and impregnated with an impregnating agent containing a binder. The impregnating agent containing the binder is often used as a solution or dispersion,
By immersing the laminate in such an impregnating agent,
It can be impregnated with a binder such as a thermosetting resin.
The impregnating agent can be prepared by dissolving or dispersing the binder in water, an organic solvent or the like. The content of the binder in the impregnating agent is, for example, 5 to 75% by weight, preferably 10 to 6%.
It is about 0% by weight. In order to adjust the amount of impregnation, the impregnated laminated body is usually subjected to a squeezing means such as a squeezing roller to remove excess impregnating agent.

The laminate subjected to the impregnation step is usually subjected to the molding step after removing the solvent in the impregnating agent by drying or the like. In this forming step, the laminate is usually heated and pressed to obtain a heat insulating material. When a thermosetting resin is used as the binder, the binder is cured by heating in the molding step, and the laminate is integrated. The heat insulating material thus obtained can be cut into a predetermined size by a cutter or the like, if necessary.

In the method (1), the binder may be impregnated not only by dipping but also by coating or spraying. Further, the fiber sheet may be previously impregnated with the binder to be laminated, but since the fiber sheet has low mechanical strength, the fiber sheet may be broken during the lamination process.

According to another method of the present invention, (2) a laminating step of laminating a plurality of layers while horizontally folding the cotton-like fiber sheet while spraying a binder on both sides of the cotton-like fiber sheet. A method of manufacturing a heat insulating material through a molding step of molding the obtained laminated body is also included. In such a method, the binder can be uniformly attached to the fiber sheet and the fiber sheet is not broken. In addition, each fiber sheet can be joined with a small amount of binder, and the density of the heat insulating material can be reduced.

FIG. 1 is a schematic perspective view showing an example of a laminated body formed of a cotton-like fiber sheet, FIG. 2 is a schematic side view for explaining a folding mechanism, and FIG. 3 is a schematic perspective view showing a binder spraying device. 4 and 5 are schematic plan views of the apparatus shown in FIG.

The fiber sheet 1 spun by a carding means such as a card machine is a conveyor 2 and a pair of belts 3.
Are continuously conveyed by and are introduced into the vertical cross wrapper 4 from above the belt 3a. In the cross wrapper 4, the fiber sheet 1 is held while being held by the pair of belts 3.
Are conveyed from the upper part to the lower part. Moreover, the fiber sheet is fed from the lower part of the cross wrapper 4 onto a mount table which can be raised or lowered or a conveyer 6 which can be moved forward, while swinging in the lateral direction by a swing mechanism capable of swinging in the thickness direction of the fiber sheet 1. It The fiber sheet 1 is folded into a plurality of layers on the conveyor 6 to form a laminated body 7. The swing mechanism is
The fiber sheet 1 is provided with a rail 5a arranged so as to extend in the thickness direction, and a roller 5b running on the rail left and right. As the roller 5b runs, the distance between the upper belt 3a and the rail 5a may fluctuate, and an external force may act on the fiber sheet 1. Therefore, in the above apparatus, the distance is kept constant by changing the inclination angle of the upper belt 3a as the roller 5b travels, and the external force is suppressed from acting on the fiber sheet 1.

In the laminating step, since the fiber sheet 1 is folded while applying a binder, the lower part of the swing mechanism is reciprocated in the width direction of the fiber sheet 1 on both sides of the fiber sheet 1. A possible spray mechanism is installed.

As shown in FIGS. 3 and 4, the spraying mechanism includes holding plates 11 attached to both sides of the lower part of the swing mechanism on the outer side of the width of the fiber sheet 1, and the holding plates 11. A pair of rails 1 mounted substantially parallel between the plates 11.
2, a pulley 13 movable along each rail 12, a mounting plate 14 to which these pulleys 13 are mounted, a hollow arm 15a mounted to this mounting plate 14, and a distal end of this arm 15a. And a nozzle 15. In order to prevent the pulleys 13 from falling off the rails 12 and to move the mounting plate 14 smoothly, each rail 12 is provided with two pulleys 13, and each pulley 13 has a rail 12a. An annular recess formed corresponding to the width of the. Further, a flexible tube or hose 16 for supplying a solution of a binder such as a thermosetting resin is connected to the arm 15a. The tip of the arm 15a is bent or curved, and the nozzle 15 faces the surface of the fiber sheet 1. Further, the nozzle 15 has a rotatable hinge mechanism 15
The spray angle is variable depending on b.

A pair of gears 18 are rotatably attached to both sides of the plate 17 of the holding plate 11, and a chain 19 is hung between the gears 18. One gear 18 is rotationally driven by a motor 21 via a belt 20 stretched between pulleys.

The mounting plate 14 is connected to the chain 19 to reciprocate the nozzle 15. A stopper 22 is attached to a portion of the plate 17 or the holding plate 11 corresponding to the width of the fiber sheet 1 so as to restrict the movement of the pulley 13 and detect arrival of the pulley. The detection signal from the stopper 22 can be used as an inversion signal for inverting the rotation direction of the motor 21.

By adopting such a mechanism, a small amount of binder (resin) can be uniformly attached to both surfaces of the fiber sheet 1. That is, as the chain 19 is moved by the rotational driving of the motor 21, the pulley 1 is moved on the rail 12.
While the nozzle 3 moves smoothly, the nozzle 15 moving in the width direction of the fiber sheet 1 can spray or spray the binder solution uniformly. In addition, the pulley 13 moved to one end
Is detected by the stopper 22, and the motor 21 moves the chain 19 in the reverse direction on the basis of the reverse signal from the stopper 22. Therefore, while the pulley 13 and the nozzle 15 are reciprocated between the stoppers 22 corresponding to the width of the fiber sheet 1, the binder solution can be uniformly sprayed or sprayed on both surfaces of the fiber sheet 1. Moreover, since it can be uniformly applied to the surface of the fiber sheet 1, not only the amount of the binder solution used can be reduced, but also the obtained laminate 7 can be integrated with a small amount of the binder, and a low bulk density laminated heat insulating material. Is useful in obtaining

Note that the number of nozzles is not limited to one, and a plurality of nozzles may be used on at least one surface side of the fiber sheet. In addition, the reciprocating mechanism of the nozzle is not limited to the above-mentioned mechanism, and various mechanisms can be adopted. For example, a sliding groove that may be annular and is formed in a region corresponding to the width of the fiber sheet A rotatable cylindrical cam which may be composed of a slider slidably arranged in the groove and having a nozzle attached thereto, and a drive mechanism (for example, a crank mechanism) for reciprocating the slider. And a spiral groove forming a loop formed on the peripheral surface of the cam, and a slider slidably arranged in the spiral groove and having a nozzle attached thereto.

In order to uniformly spray the resin liquid in the width direction of the fiber sheet by the fixed nozzle, it is usually necessary to spray a large amount of the resin liquid by a plurality of nozzles, so that the bulk density of the heat insulating material is reduced. There is a limit to what you can do. On the other hand, when the nozzle reciprocates in the width direction of the fiber sheet, a small amount of resin liquid can be uniformly sprayed, and the increase in bulk density of the heat insulating material can be suppressed.

The laminated body obtained as described above is often subjected to the drying, curing and molding steps as in the method (1). If necessary, the folded end of the obtained laminate or heat insulating material may be cut in the laminating direction to obtain a low density laminated heat insulating material.

The low-density laminated heat insulating material of the present invention is lightweight and highly incombustible, flame-retardant, heat-resistant, safe, repulsive at the time of construction, vibration-resistant and field-applicable. Therefore, it can be used not only as a heat insulating material for a high-speed moving object such as a railroad vehicle, a long distance bus, a high-speed ship, and an aircraft, but also as a sound absorbing heat insulating material and a sound insulating material.

[0049]

INDUSTRIAL APPLICABILITY The heat insulating material of the present invention contains crimped fibers, a specific amount of fibers is composed of carbonaceous fibers, and has a laminated structure laminated in a specific direction. It is lightweight and has high resilience, repulsion, and vibration durability. In addition, since it contains carbonaceous fibers, it has high non-combustibility or flame retardancy, heat resistance and safety, and can be adhered to the heat-insulated site only by interposing it in the heat-insulated site due to the resilience and restoration property. Since it does not have a tingling sensation, it has high workability and heat insulation. Therefore, it is useful as a sound absorbing and heat insulating material for a high-speed moving body that is required to be lightweight.

According to the method of the present invention, the low-density laminated heat insulating material having the above-mentioned excellent properties can be obtained by a simple operation.

[0051]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited by these examples.

Example 1 A bulky crimped pitch-purpose general-purpose carbon fiber spun by the vortex method (DONAC CO., LTD., Dona Carbo, average fiber diameter 13 μm, average fiber length 75 mm) was opened and a metallic card machine ( It was sequentially supplied to Ikegami Machinery Co., Ltd., 60-MDK to obtain a cotton-like fiber sheet having an average thickness of 7 mm. The bulk density of this fiber sheet was 5.7 kg / m ³ . Spray molding machine (vertical cross wrapper manufactured by Iwamoto Manufacturing Co., Ltd.)
While traversing one nozzle disposed on each side of the fiber sheet having a three-dimensional network structure, while spraying a small amount of the phenol resin solution evenly on both sides of the web,
While advancing the conveyor horizontally at a speed of 0.6 m / min, the fiber sheet was folded with a width of 1.2 m to obtain a laminated continuous body of 20 layers. When spraying the resin liquid, a spray device (manufactured by Spraying Systems Japan, model number TG
0.6, 1-fluid full cone spray tip) was used, and the spray pressure was 1.5 kg / cm ² (gauge pressure).
Further, as the resin liquid, a mixed liquid of 20 parts by weight of a water-soluble phenol resin (Sumilite resin, manufactured by Sumitomo Dures Co., Ltd.) and 80 parts by weight of water was used.

The laminated continuous body, to which the resin has been attached by spraying and which has been folded, is cut into a length of 2.25 m using a rotary cutter (supplier company),
A resin-adhered laminate (1.2 m × 2.25 m) weighing 973 g per square meter was obtained.

The resin-adhered laminate was inserted into a hot air circulation type curing oven (cure oven) having a plurality of shelf structures and a thickness adjusting function, and the thickness adjusting plates were spaced at a distance of 50 mm and a temperature of 23.
A low density laminated heat insulating material (1.2 m × 2.25 m × thickness 50 mm) was obtained by heating and curing at 0 ° C. for 30 minutes.
Weight per square meter of low density laminated insulation is 60
It was 5 g (bulk density 12.1 kg / m ³ ), and when the resin content was calculated, it was about 10% by weight based on the whole heat insulating material.

In order to evaluate the heat insulation performance, the flat plate comparison method (J
The thermal conductivity of the heat insulating material was measured by IS A1412) and found to be 0.046 kcal / m · h · ° C (average temperature 7
0 ° C condition), 0.039 kcal / m · h · ° C (average temperature 40 ° C condition) and 0.036 kcal / m · h · ° C
(Average temperature of 25 ° C.). Furthermore, when a material combustion test for railway vehicles (vehicle test 65-599) was performed, it was confirmed to be a non-combustible material, and when subjected to a vibration test method for railway vehicle parts (JIS E4031), no abnormalities were confirmed. It was Further, when the thickness restoration ratio was measured, it was restored to the original thickness and was about 100%. further,
When the repulsive force of the heat insulating material when compressed to 1/2 of the original thickness is measured, it has a high repulsiveness of 1.2 g / cm ² and does not have the tingling sensation of glass fiber, It could also be used favorably in construction.

Example 2 The pitch-based general-purpose carbon fiber of Example 1 was fed to an opening machine and a metallic card machine in the same manner as in Example 1, and a cotton-like fiber sheet having an average thickness of 7 mm (bulk density: 5.7 kg / m ³ )
Got The spun web is fed to a web forming machine (horizontal cross layer manufactured by Ikegami Kikai Co., Ltd.), and 0.6 m
It was folded with a width of 1.2 m on a conveyor moving forward at a speed of / minute to obtain a laminated continuous body of 20 layers.

The folded continuous laminated body was cut into a length of 2.25 m using a rotary cutter (supplier company), and the laminated body (1.2 m × 2.25 m, weight 595 g per square meter). ) Got.

Both sides of the laminate were sandwiched by open glass cloths and immersed in an impregnation bath to allow the resin solution to permeate the laminate. As the resin liquid, a mixed liquid of 10 parts by weight of a water-soluble phenol resin (Tamanol manufactured by Arakawa Chemical Co., Ltd.) and 90 parts by weight of methanol was used. Excess resin liquid of the laminate is squeezed using a squeezing roll, the glass cloth is removed, and then naturally dried at room temperature to obtain a resin-impregnated laminate (1.2 m × 2.25 m, per square meter). A weight of 1733 g) was obtained.

The resin-impregnated laminate was inserted into the hot air circulation type curing oven (cure oven) used in Example 1 and heat-cured at a temperature of 170 ° C. for 60 minutes at a space of 50 mm between thickness adjusting plates.
Four sides of the heat insulating molded heat insulating material were trimmed (ear cut) by the rotary cutter to obtain a low density laminated heat insulating material (1.05 m × 2.1 m × thickness 50 mm). The weight of the heat insulating material was 665 g per square meter (bulk density: 13.3 kg / m ³ ), and the resin content was about 12% by weight based on the whole heat insulating material.

When the thermal conductivity of the molded body was measured in the same manner as in Example 1, it was 0.044 kcal / m · h · ° C.
(Average temperature 70 ° C.). Further, in the material combustion test for railway vehicles, it corresponds to a non-combustible material, and it was confirmed by the vibration test method of railway vehicle parts that there was no abnormality, and the thickness restoration rate was about 100%. Furthermore, the repulsive force when compressed to 1/2 of the original thickness is 1.6 g / cm ² , which has high resilience and does not have the tingling sensation of glass fiber, and is suitable for actual vehicle construction. It could be used suitably.

Comparative Example 1 A heat insulating material (thickness: 50 mm, bulk density: 14 kg //) prepared by mixing 70 parts by weight of polyacrylonitrile (PAN) type carbon fiber (flameproofing fiber) and 30 parts by weight of polyester fiber.
m ³ ), the thermal conductivity was 0.045.
kcal / m · h · ° C (70 ° C), thickness restoration rate = 70
%, Repulsive force when compressed to 1/2 = 0.2 g / cm ²
Met. When the heat insulating material was exposed to a flame, the polyester fiber was melted, and HCN gas and NH
_Three gases were produced.

Comparative Example 2 The characteristics of a glass wool heat insulating material (thickness 50 mm, bulk density 20 kg / m ³ ) produced by using glass fibers were measured to find that the thermal conductivity was 0.039 kcal / m · h · ° C.
(Average temperature 40 ° C), repulsive force when compressed to 1/2 =
It was 1.6 g / cm ² . The above heat insulating material is
There was a tingling sensation that melted when exposed to the flame.
Further, in order to obtain the same heat insulation performance as compared with the heat insulation material of Example 1, about 1.7 times the weight was required.

Example 3 70 parts by weight of the pitch-based general-purpose carbon fiber used in Example 1 and 30 parts by weight of flame-retardant polyester cotton were respectively fed to an opening machine and then mixed and fed to a metallic card machine. A thin cotton fiber sheet was obtained. This fiber sheet was used in Example 1.
And spraying the resin liquid on both sides of the fiber sheet, and folding it with a width of 1.2 m on a conveyor moving at a speed of 0.6 m / min to obtain a laminated continuous body of 20 layers. It was As the resin liquid, a mixed liquid of 50 parts by weight of a water-soluble phenolic resin (Register Top manufactured by Gunei Chemical Co., Ltd.) and 50 parts by weight of water was used and sprayed at a spray pressure of 1.0 kg / cm ² (gauge pressure).

The obtained laminated continuous body was cut with a rotary cutter in the same manner as in Example 1, and the resin-attached laminated body (1.2 m) having a weight per square meter of 923 g was cut.
X2.25 m) was obtained.

The resin-adhered laminate was inserted into the hot air circulation type curing oven (cure oven) used in Example 1 and heat-cured at a temperature of 170 ° C. for 30 minutes at a thickness adjusting plate interval of 50 mm.
Four sides of the heat insulating molded heat insulating material were trimmed (ear cut) by the rotary cutter to obtain a low density laminated heat insulating material (1.05 m × 2.1 m × thickness 50 mm). The weight of the heat insulating material was 695 g per square meter (bulk density: 13.9 kg / m ³ ), and the resin content was about 14% by weight based on the whole heat insulating material.

When the thermal conductivity of the molded body was measured in the same manner as in Example 1, it was 0.043 kcal / m · h · ° C.
(Average temperature 70 ° C.). Further, in the material combustion test for railway vehicles, it corresponds to a non-combustible material, and it was confirmed by the vibration test method of railway vehicle parts that there was no abnormality, and the thickness restoration rate was about 100%. Furthermore, the repulsive force when compressed to 1/2 of the original thickness is 1.8 g / cm ² , which is highly repulsive and does not have the tingling sensation of glass fiber, and is suitable for actual vehicle construction. It could be used suitably.

Example 4 In the same manner as in Example 3 except that 70 parts by weight of the pitch-based general-purpose carbon fiber used in Example 1 and 30 parts by weight of rayon cotton were used, the resin-adhered laminate was heat-cured to be molded and heat-insulated. I got the material. Trimming (ear cut) the four sides of the molded heat insulating material with the rotary cutter, and low density laminated heat insulating material (1.05 m
X 2.1 m x thickness 50 mm) was obtained.

Weight of insulation is 65 per square meter
It was 1 g (bulk density 13.0 kg / m ³ ). In addition, when the resin content of the whole molded product was calculated, it was about 12
% By weight.

When the thermal conductivity of the molded article was measured in the same manner as in Example 1, it was 0.044 kcal / m · h · ° C.
(Average temperature 70 ° C.). Further, in the material combustion test for railway vehicles, it corresponds to a non-combustible material, and it was confirmed by the vibration test method of railway vehicle parts that there was no abnormality, and the thickness restoration rate was about 100%. Furthermore, the repulsive force when compressed to 1/2 of the original thickness is 1.5 g / cm ² , which has high resilience and does not have the tingling sensation of glass fiber, and is suitable for actual vehicle construction. It could be used suitably.

The results of the above Examples and Comparative Examples are shown in the table below. The vibration durability, safety, heat resistance and workability were evaluated on the basis of excellent (◯), good (Δ), and poor (x).

[0071]

[Table 1]

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a laminated body.

FIG. 2 is a schematic side view for explaining a folding mechanism.

FIG. 3 is a schematic perspective view showing a binder spraying device.

FIG. 4 is a schematic plan view of the device shown in FIG.

[Explanation of Codes] 1 ... Cotton fiber sheet 7 ... Laminated body 12 ... Rail 13 ... Pulley 15 ... Nozzle 18 ... Gear 19 ... Chain

Claims (13)

[Claims] 1. A crimped fiber is included, and 50 to 50% of the entire fiber is included.
A cotton-like fibrous sheet composed of 100% by weight of carbonaceous fibers is composed of a laminate in which a plurality of layers are laminated in the thickness direction, and a binder for joining at least each layer of the laminate, A low-density laminated heat insulating material having a density of 5 to 20 kg / m ³ . 2. The cotton-like fiber sheet has a fiber length of 0.1 to 10.
The low-density laminated heat insulating material according to claim 1, which is composed of 50 to 100% by weight of the crimped carbonaceous fiber having a size of cm and 0 to 50% by weight of the other fiber. 3. The low-density laminated heat insulating material according to claim 1, wherein the crimped carbonaceous fibers are pitch-based carbon fibers. 4. The low density laminated heat insulating material according to claim 1, wherein the cotton-like fiber sheet contains 50% by weight or more of carbonized carbon fibers. 5. The low density laminated heat insulating material according to claim 1, wherein five or more layers of cotton-like fiber sheet having a thickness of 0.1 to 20 mm are folded. 6. The low-density laminated heat insulating material according to claim 1, wherein the binder is composed of a thermosetting resin, and the content of the thermosetting resin is 5 to 20% by weight based on the whole heat insulating material. 7. The low-density laminated heat insulating material according to claim 1, which has a bulk density of 8 to 18 kg / m ³ . 8. A cotton-like fibrous sheet having a thickness of 0.5 to 15 mm, containing 50 to 100% by weight of crimped pitch-based carbonaceous fibers having a fiber length of 0.5 to 8 cm in all the fibers, in a thickness direction of 7.
.About.50 layers and a thermosetting resin in which at least each layer of the laminate is bonded and the ratio to the laminate is 7 to 18% by weight, and the bulk density is 10 to 16.
Low-density laminated insulation with kg / m ³ . 9. A crimped fiber is included, and 50 to 50% of the entire fiber is included.
A method for producing a low-density laminated heat insulating material, comprising laminating a plurality of layers while laterally folding a cotton-like fiber sheet composed of 100% by weight of carbonaceous fibers, impregnating the obtained laminate with a binder, and molding. 10. Crimped fiber is included and 50 of the entire fiber is included.
The binder is sprayed on both sides of a cotton-like fiber sheet composed of 100% by weight of carbonaceous fiber, and the cotton-like fiber sheet is laterally folded to be laminated into a plurality of layers to form a laminate. Method for producing low-density laminated heat insulating material. 11. A thermosetting resin is sprayed on both sides of the cotton-like fiber sheet by a spraying device that is movable in the width direction on both sides of the cotton-like fiber sheet while reciprocating the cotton-like fiber sheet in the thickness direction. The method for producing a low-density laminated heat insulating material according to claim 10, wherein the obtained laminated body is heat-molded. 12. The method for producing a low-density laminated heat insulating material according to claim 9, wherein a cotton-like fiber sheet having a bulk density of 0.1 to 15 kg / m ³ is folded. 13. The method for manufacturing a low-density laminated heat insulating material according to claim 9, wherein the bent end portion is cut in the laminating direction.