JP2012040827A - Method of manufacturing heat insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an inexpensive heat insulating material showing a low heat conductivity at an environmental temperature in a predetermined range.SOLUTION: The method includes three processes. In a first process, 25 wt.% mica powder and 50 wt.% sepiolite are kneaded with 25 wt.% powdery phenol resin. In this process, 8 wt.% methanol is injected. In a second process, a base material 19 is preheated to 120°C by irradiating the base material 19 with a high frequency wave. In a third process, the preheated base material 19 is molded by a mold. In such a case, the base material 19 is heated to 170°C and compressed at 20 MPa. The heating and pressurizing time is 12 min.

Description

  The present invention relates to a method for manufacturing a heat insulating material that maintains a low temperature environment by separating the high temperature environment and the low temperature environment. Such a heat insulating material is applied, for example, to a member that separates a pressing device that operates on a caliper from a brake lining around a high temperature in a braking device for a railway vehicle.

  For example, a Shinkansen vehicle includes a braking device (braking device). The braking device includes a brake disk that rotates as the vehicle travels, and a brake lining that slides on the disk to convert the vehicle's kinetic energy into thermal energy to perform braking. The brake lining is provided on the caliper and is pressed against the brake disc via a required pressing device. The pressing device conventionally employs an air-hydraulic conversion method, and converts the air pressure into oil pressure to operate the caliper. In this method, a pressure increasing cylinder for converting air pressure to oil pressure is required, and the structure is complicated. In recent years, a brake device using only air pressure has been proposed (see, for example, Patent Document 1). .

JP 2009-92194 A

  A brake device using only air pressure that has been proposed in recent years employs a diaphragm type. When compressed air is supplied to this type of device, a diaphragm made of a rubber-based material pushes out the brake lining, and the brake lining slides against the brake disc, thereby exerting a braking force. Since part of the braking energy is converted into heat, the brake lining becomes hot (environmental temperature of about 300 ° C.), and the diaphragm may be damaged when the brake lining and the diaphragm are in direct contact with each other. There is. For this reason, a heat insulating means for separating the diaphragm from the high temperature environment is required.

  The present invention has been made based on such a background, and provides a new method for manufacturing a heat insulating material that can be used as a heat insulating measure in the vehicle braking device as described above. However, various heat insulating materials have been proposed in the past, and an object of the present invention is to provide an inexpensive method for manufacturing a heat insulating material that exhibits a sufficient heat insulating effect in the aforementioned temperature environment.

  (1) In the heat insulating material manufacturing method according to the present invention, the base material is produced by kneading 15 wt% to 30 wt% mica powder and 40 wt% to 60 wt% sepiolite in a phenol resin. A step, a second step in which the base material is preheated to 120 ° C. to 130 ° C. by irradiation with high frequency, the preheated base material is heated to 165 ° C. to 175 ° C., and 16.5 MPa to 24 And a third step compressed at 5 MPa.

  According to this structure, the base material produced | generated by a 1st process exhibits a heat insulation effect. That is, sepiolite is a clay mineral whose main component is hydrous magnesium silicate, and excellent heat insulation performance is exhibited by mixing mica powder as an inorganic filler. In addition, when the phenol resin is kneaded, the mica powder as the inorganic filler is molded (solidified) by the phenol resin, so that the base material has a desired shape by adopting the mold molding. It can be formed relatively easily. That is, the degree of freedom in designing the shape of the base material is improved. In the second step, since the base material is induction-heated by high frequency, the materials constituting the base material, that is, phenol resin, sepiolite and mica powder are uniformly preheated from the inside. In the third step, the substrate is subjected to heat compression molding, and in this step, molding using a mold is generally performed. And since the above-mentioned preheating is performed in the said 2nd process, in the 3rd process, it heat-processes well to the inside of a base material, and the heat insulation performance of the base material as a molded article improves. Furthermore, since the temperature and pressure in the third step are set in the above-described range, there is an advantage that the heating and compression work is relatively simple and the processing is inexpensive. In addition, since the third step can be molded by a mold, it is easy to perform insert molding using another functional component (typically, a mounting stay or other fixing bracket) as an insert member.

  (2) The phenol resin kneaded in the first step is preferably a powder. The first step preferably includes a step in which methanol is mixed by 8 wt% to 10 wt% with respect to the base material. Furthermore, in the first step, it is preferable that sepiolite, mica powder and phenol resin are put in a predetermined kneading container in that order.

  Thereby, sepiolite, mica powder, and powdered phenol resin are kneaded more uniformly.

  According to the present invention, phenol resin is kneaded into mica powder and sepiolite, and heat compression molding is performed in a state of being uniformly preheated to the inside by induction heating. It can be manufactured easily and inexpensively. In addition, since insert molding is possible using the functional component as an insert member, the necessary fittings and the like are integrally formed according to the application, and therefore a heat insulating material suitable for the place of use can be manufactured at low cost.

FIG. 1 is a schematic view of a kneading apparatus 10 used in a heat insulating material manufacturing method according to an embodiment of the present invention. FIG. 2 is a schematic diagram of the high-frequency generator 26 according to one embodiment of the present invention. FIG. 3 is a schematic view of a molding apparatus 11 provided for the heat insulating material manufacturing method according to one embodiment of the present invention. FIG. 4 is a flowchart of a heat insulating material manufacturing method according to an embodiment of the present invention. FIG. 5 is a diagram showing a heat insulating material manufactured by a heat insulating material manufacturing method according to an embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with appropriate reference to the drawings.

  FIG. 1 is a schematic view of a kneading apparatus 10 used in a heat insulating material manufacturing method according to an embodiment of the present invention, where (a) is a partially sectional plan view, and (b) is a partially sectional front view. is there. FIG. 2 is a diagram schematically showing the high frequency generator 26 according to one embodiment of the present invention. FIG. 3 is a diagram schematically showing the molding apparatus 11 used in the heat insulating material manufacturing method according to the embodiment of the present invention, and the process proceeds in the order of (a) to (d). Furthermore, FIG. 4 is a flowchart of the heat insulating material manufacturing method according to an embodiment of the present invention.

  The heat insulating material manufactured by the heat insulating material manufacturing method according to the present embodiment is configured by kneading mica and sepiolite in a phenolic resin and subjecting it to a predetermined heat treatment. In the manufacturing method according to the present embodiment, powdered phenolic resin and mica are used in the manufacturing process. Of course, phenol resins other than powder may be employed.

  The kneading apparatus 10 shown in FIG. 1 can generate a base material 19 (see FIG. 1B) by uniformly mixing phenol resin, mica, and sepiolite. The kneading apparatus 10 includes a casing 12 and a stirring blade 15 disposed at the bottom of the casing 12. The casing 12 includes a main body 13 (corresponding to a “kneading container” described in claims) and a lid 14. Note that the illustration of the lid 14 is omitted in FIG. The stirring blade 15 has a rotating shaft 16 and blades 17 and 18. The main body 13 can accommodate a predetermined amount of raw materials (in this embodiment, phenol resin, mica, sepiolite, which will be described later). The lid 14 can seal the raw material in the main body 13 by being attached to the main body 13. When the rotary shaft 16 is driven by a motor (not shown) or the like, the blades 17 and 18 are rotated, and the raw materials put into the main body 13 are mixed to generate the base material 19.

  The base material 19 produced by mixing the raw materials is heated (preheated) to a predetermined temperature in advance. A high frequency generator 26 is applied to this pre-heat treatment (see FIG. 2). The base material 19 is accommodated in a required container 27 and placed on the table 28 of the high frequency generator 26. The high frequency generator 26 has a known structure and includes a high frequency generation circuit 29. The high frequency generated by the high frequency generation circuit 29 is applied to the base material 19 disposed on the table 28. Thereby, the base material 19 is heated by what is called high frequency induction heating.

  The molding apparatus 11 shown in FIG. 3 can manufacture a heat insulating material 20 (see FIG. 3D) as a product by heating and compressing a base material 19 (see FIG. 3B). The molding apparatus 11 includes a main frame 21 and a sub frame 22 provided in a lower portion of the main frame 21, an upper mold 23 and a lower mold 24 installed in the main frame 21 and the sub frame 22, respectively, And a middle mold 25 disposed in the middle.

  The subframe 22 is slid in the vertical direction in the figure by a hydraulic cylinder device (not shown). Thereby, the upper mold 23 and the lower mold 24 perform mold clamping / mold opening. The middle mold 25 and the lower mold 24 form a cavity when the upper mold 23 and the lower mold 24 perform clamping. This cavity prescribes | regulates the shape of the heat insulating material 20 formed after the base material 19 is heat-pressed. Therefore, by changing the shapes of the upper mold 23, the lower mold 24, and the middle mold 25, the heat insulating material 20 having a required shape can be molded.

  The molding apparatus 11 can perform insert molding. In the present embodiment, the upper mold 23 includes a cage (not shown) and can hold a required insert part. Such an insert part is typically a mounting stay or other fixing bracket. However, the insert part is not limited to this, and various functional parts can be adopted. In this embodiment, the stay 31 for attaching the heat insulating material 20 as a molded product to a predetermined part is inserted.

  Next, a specific method for manufacturing the heat insulating material 20 will be described with reference to FIG.

[First step]

  As raw materials, powdered phenol resin, mica powder and sepiolite are adopted and weighed (step S1). The ratio of these raw materials is 50% by weight for sepiolite, 25% by weight for mica powder and 25% by weight for powdered phenol resin. Further, sepiolite may be 52% by weight, mica powder may be 16% by weight, and powdered phenol resin may be 32% by weight. The ratio of the raw materials is not limited to this, and other mixing ratios may be adopted as long as sepiolite is 40 wt% to 60 wt% and mica powder is 15 wt% to 30 wt%. .

  The weighed raw materials are put into the main body 13 of the kneading apparatus 10 and the rotary shaft 16 is driven. As a result, the blades 17 and 18 are rotated, and the base materials 19 are generated by mixing the raw materials (step S2). At this time, in this embodiment, methanol is injected into the main body 13. The amount of methanol is 8% by weight with respect to the base material 19. However, the amount of methanol injected may be 8 to 10% by weight. Thereby, the raw materials are kneaded very uniformly. Of course, the equipment 19 can be produced by mixing raw materials even if methanol is not injected.

[Second step]

  After the base material 19 is kneaded, the base material 19 is high-frequency heated by the high-frequency generator 26 (step S3). The base material 19 is irradiated with a high frequency for a predetermined time with a predetermined output. Thereby, the base material 19 is preheated to 120 degreeC. In addition, the preheating temperature of the base material 19 is set to 120 ° C to 130 ° C.

[Third step]

  The preheated base material 19 is put into the molding apparatus 11. First, as shown in FIG. 3A, before the base material 19 is inserted, the sub-frame 22 moves downward and the mold is opened. Then, the preheated base material 19 is accommodated in the cavity defined by the middle mold 25 and the lower mold 24 (see FIG. 5B). Simultaneously with this operation, the stay 31 is mounted on the upper mold 23.

  Next, the lower mold 24 is raised by the hydraulic cylinder device, and the mold is clamped (see FIG. 10C). Heated simultaneously with mold clamping. This heating is performed by a heater (not shown). At this time, the pressure applied to the base material 19 is 20 MPa, and the base material 19 is heated to 170 ° C. The pressure heating time is 12 minutes in this embodiment. Thereby, the heat insulating material 20 is produced | generated (step S4). However, although the pressure, temperature, and time applied to the base material 19 are changed depending on the composition ratio of the raw materials, the temperature is 165 ° C. to 175 ° C., the pressure is 16.5 MPa to 24.5 MPa, and the time is 10 minutes. Set to ~ 15 minutes.

  Thereafter, the lower mold 24 is moved downward by the hydraulic cylinder device to open the mold. The molded heat insulating material 20 is taken out from the lower mold 24 (step S5). The heat insulating material 20 taken out from the molding apparatus 11 is cooled and finished on the surface or the like to become a product.

  FIG. 5 shows the heat insulating material 20 manufactured as described above. FIG. 5A is a plan view, FIG. 5B is a partial cross-sectional front view, and FIG. 5C is a bottom view. .

  The heat insulating material 20 is applied to, for example, a railway vehicle brake device, particularly a pneumatic brake device using a diaphragm. Specifically, the heat insulating material 20 is interposed between the diaphragm and the brake lining, and separates the diaphragm from the high temperature environment. Although the outer shape of the heat insulating material 20 according to the present embodiment is an ellipse, this is a request on the brake device side to which the heat insulating material 20 is attached. Therefore, the shape of the heat insulating material 20 can be variously changed according to the application. The heat insulating material 20 includes a stay 31. Since the stay 31 is inserted as described above, the stay 31 is firmly fixed to the heat insulating material 20. A positioning hole 30 is provided at a predetermined position of the heat insulating material 20. This hole 30 is also easily provided by a mold. But the hole 30 may be abbreviate | omitted.

  The sepiolite is a clay mineral containing hydrated magnesium silicate as a main component, and the heat insulating material 20 constituted by mixing mica powder as an inorganic filler therein is in a certain temperature range (300 ° C. or less). Excellent heat insulation performance in The physical property values of the heat insulating material 20 according to the present embodiment are as follows.

Thermal conductivity 0.78 to 1.05 W / mk
Compressive strength 130MPa
Hardness HR _L 100 (JIS G 0202 Rockwell hardness)
Specific gravity 2.1
Water absorption rate 2.3%
Charpy impact value 1.5 kJ / m ²

  Moreover, since the said base material 19 is a thing by which the powder phenol resin was knead | mixed, the said mica powder is solidified with a powder phenol resin. That is, when the heat insulating material 20 is formed by molding as in the present embodiment, the shape of the heat insulating material 20 as a product is mass-produced relatively easily. Therefore, the outer shape of the heat insulating material 20 can be easily and inexpensively formed into an appropriate shape according to the application by changing the mold, and there is an advantage that the degree of freedom of design is increased.

  In particular, since the base material 19 is preheated by high frequency before being heated and pressurized, the powdered phenol resin, sepiolite and mica powder constituting the base material 19 are uniformly mixed. Therefore, the heat insulation performance of the heat insulating material 20 is further improved. In addition, since the temperature and pressure of the base material 19 are in the above-described degree, the heating and compressing operation is relatively simple and processed at a low cost.

  In the heat insulating material 20, functional parts such as the stay 31 can be easily installed at a required position at the time of molding. The reason is none other than the fact that insert molding as described above is possible, but as a result of such functional parts being easily installed, the retrofitting work of the functional parts to the heat insulating material 20 becomes unnecessary, and as a result, The manufacturing cost of the heat insulating material 20 is significantly reduced. In addition, since the heat insulating material 20 as a molded product is kneaded with phenol resin, there is an advantage that subsequent machining and the like are easy. Therefore, necessary drilling and chamfering can be easily performed on the molded heat insulating material 20.

  Further, since the heat insulating material 20 is configured by heat compression molding using the upper mold 23, the lower mold 24, and the middle mold 25, the surface roughness of the heat insulating material 20 as a molded product can be set to be extremely small. . Thereby, even if it is a case where the heat insulating material 20 contacts directly with the other party member which is easy to damage like a diaphragm, there exists an advantage that the said other party member is not damaged.

DESCRIPTION OF SYMBOLS 10 ... Kneading apparatus 11 ... Molding apparatus 13 ... Main body 14 ... Cover 19 ... Base material 20 ... Heat insulating material 26 ... High frequency generator

Claims (4)

A first step in which a base material is produced by kneading 15 wt% to 30 wt% mica powder and 40 wt% to 60 wt% sepiolite in a phenol resin;
A second step in which the substrate is preheated to 120 ° C. to 130 ° C. by being irradiated with a high frequency;
A heat insulating material manufacturing method comprising: a third step in which the preheated base material is heated to 165 ° C. to 175 ° C. and compressed at 16.5 MPa to 24.5 MPa.   The heat insulating material manufacturing method according to claim 1, wherein the phenol resin kneaded in the first step is a powder.   The said 1st process is a heat insulating material manufacturing process of Claim 2 including the process by which methanol is mixed only 8weight%-10weight% with respect to the said base material. The heat insulating material manufacturing method according to any one of claims 1 to 3, wherein in the first step, sepiolite, mica powder, and phenol resin are charged in a predetermined kneading container in that order.

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