JP2008266856A - Heat insulating material and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat insulating material used for a heat insulating position in an electromagnetic induction heater or the like, and a method for manufacturing it which are improved so that no decrease or little decrease in strength may be generated after heating and no smell may be generated during heating. <P>SOLUTION: The heat insulating material 10 prepared by making a paper by using an inorganic fiber 13 comprising a ceramic fiber (silica fiber) 12 and an attapulgite 11, is used. In this case, the composition ratio of the attapulgite 11 to the inorganic fiber 13 is set at 10-50%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat insulating material suitable for an electric heating device, a heat insulating material for a heating device, a sealing material for a high temperature portion, or the like.

  This type of heat insulating material is, for example, one that is molded by adding a foaming agent or the like to a synthetic resin, or one that is used as a mat by adding a synthetic resin to a melted ore and made into a cotton-like shape In general, however, a means for reinforcing and molding the heat insulating member by adding an organic binder is employed. That is, in recent years, as disclosed in Patent Document 1, a heat-resistant ceramic sheet formed by binding inorganic fibers composed of ceramic fibers and glass fibers with an organic binder, that is, heat insulation composed of a synthetic resin and an organic binder. A lot of materials have been used.

However, a heat insulating material made of a synthetic resin and an organic binder is excellent in mold retention, but has a property of reducing strength after heating. In addition, a heat insulating material composed of a synthetic resin and an organic binder has a property that odor is generated during heating or smoke is easily generated, and there is still room for improvement.
Japanese Patent Publication No. 6-17277

  An object of the present invention is to provide an improved heat insulating material and a method for producing the same so that there is no or little reduction in strength after heating, and no odor or smoke is generated during heating.

  The invention according to claim 1 is characterized in that, in the heat insulating material, the paper is made by using the inorganic fiber 13 having the ceramic fiber 12 and the attapulgite 11.

  The invention according to claim 2 is characterized in that, in the heat insulating material according to claim 1, the constituent ratio of the attapulgite 11 to the inorganic fibers 13 is set to 10 to 50%.

  The invention according to claim 3 is characterized in that, in the heat insulating material according to claim 1 or 2, the heat insulating material is used in a heat insulating portion in the electromagnetic induction heater.

  The invention according to claim 4 is a method for producing a heat insulating material, wherein a mixing step a for mixing the ceramic fiber 12 and the attapulgite 11 to create the inorganic fiber 13 and a paper making step b for making a paper using the inorganic fiber 13 , Characterized by having.

  The invention according to claim 5 is the method for manufacturing a heat insulating material according to claim 4, wherein, in the mixing step a, the constituent ratio of the attapulgite 11 to the inorganic fibers 13 is set to 10 to 50%. It is what.

  According to the invention of claim 1, since the heat insulating material is formed by paper making using inorganic fibers having ceramic fibers and attapulgite, the conventional heat insulating material formed by adding an organic binder Compared to the above, it is excellent in mold retaining system formability, and strength reduction after heating can be reduced. Moreover, there is no smell and smoke at the time of a heating, and it is preferable. As a result, it is possible to provide an improved heat insulating material that has no or little decrease in strength after heating and that does not generate odor or smoke during heating.

  According to invention of Claim 2, it becomes a thing with a small bulk density (refer FIG. 1), and can provide the heat insulating material which has the more excellent heat insulation. The heat insulating material by this invention can be effectively used for the heat insulation location in an electromagnetic induction heater like Claim 3.

  The invention of claim 4 is a method of the invention of claim 1 and claim 5 is a method of the invention of claim 2, respectively, and can obtain an effect equivalent to the effect according to the corresponding claim.

  Embodiments of a heat insulating material and a method for manufacturing the same according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a tensile test result table in each example and each comparative example of a heat insulating material, FIG. 2 is a principle diagram showing a manufacturing method of the heat insulating material, and FIG. 3 is an operation diagram showing another example of papermaking.

  As shown in FIGS. 2 and 3, the heat insulating material according to the present invention is formed by paper making using inorganic fibers 13 having silica fibers (an example of ceramic fibers) 12 and attapulgite 11. The composition ratio with respect to the inorganic fiber 13 is set to 10 to 50%.

  Attapulgite (Poratey: trade name) is an industrial inorganic raw material (hydrous magnesium silicate mineral) specially processed from a fibrous clay mineral produced in nature. Its properties have many properties such as thixotropic properties, adsorptivity and plasticity, and a wide range of applications are expected. That is, when attapulgite is powdered and heat-treated (heated to 100 ° C. to 200 ° C.), the zeolitic water escapes and becomes a cavity, increasing the adsorption power. In addition, because the fibrous structure is intertwined, it exerts a strong viscosity when immersed in water, pesticide carrier, adhesive, caking material, building material interior / exterior board conditioning material, viscosity, conditioning agent, feed, water purification agent, chemical・ Can be used for oil bleaching agents.

The main component of attapulgite is palygorskite (hydrous magnesium aluminum silicate), and the chemical structure is represented by (Mg, Al) ₅ Si ₈ O ₂₀ (OH) _2. (OH ₂ ) ₄ .4H ₂ O. The crystal structure is in the form of a hollow fiber, and several tunnels are vacated along the entire length, and these tunnels contribute to a unique adsorption effect. In addition, calcite, quartz, smectite, chlorite and the like are included as impurities.

  In other words, attapulgite is a fibrous substance having a length of 15 to 20 μm mainly composed of silicon dioxide, and has excellent crystallinity and adsorbability and heat resistance. It is used as a sealing material by mixing it with rubber or the like, and has a property of maintaining a cushioning property even at about 600 ° C. at almost the same high temperature as asbestos. It is also possible to use paper as a liquid filter medium. Because the fiber shape is similar to asbestos, existing production lines can be used, but there is no thorn like asbestos, and the risk of piercing the lungs even when inhaled is small, so it is effective as an asbestos alternative material.

  As shown in FIG. 2, the heat insulating material is produced by mixing the silica fiber 12 and the attapulgite 11 to create the inorganic fiber 13 and the paper making using the inorganic fiber 13 created by the mixing step a. And a paper making step b. In the mixing step a, the composition ratio of the attapulgite 11 to the inorganic fibers 13 is set to 10 to 50%. In the paper making process b, a square sheet paper machine, which will be described later, is used. Another example is the method shown in FIG.

  That is, as shown in FIG. 3, a dispersion (inorganic fiber) 13 of silica fiber 12, attapulgite 11, and water 9 is placed in hopper 1 and wound around rollers 2 and 3 from outlet 1a at the lower end of hopper 1. The dispersion liquid is dropped and supplied onto the upper surface of the endless rotating belt-like wire mesh 4 on the conveyance start end side. While being conveyed in the direction of arrow A on the wire mesh 4, the dispersion liquid is sprinkled (drawn) to form an approximate sheet-like body, and along the large-diameter lifting drum 5 from the conveyance end of the wire mesh 4. This is a papermaking step b in which a heat insulating material sheet (papermaking sheet) 8 is formed by passing between a plurality of upper and lower finishing rollers 6 and 7 after being lifted and conveyed. The heat insulating material 10 actually used may be used by laminating a plurality of the heat insulating material sheets 8.

  Several examples related to the cut-off material sheet produced as described above and a comparative example were prepared and subjected to a tensile test. In the tensile strength test, the tensile strength of the obtained heat insulating material sheet was measured at room temperature and after heating at 400 ° C. for 12 hours. The specimen has a width of 15 mm and a length of 50 mm, and the tensile strength at a pulling speed of 5 mm / min is obtained using a digital force gauge (eg, Nidec Sympo). The characteristic comparison table | surface which calculated | required the tension test result and the bulk density is shown in FIG. In addition, the test result of each Example and each comparative example is as follows.

[Examples 1 to 4]
Square sheet paper made of slurry obtained by dispersing attapulgite mineral [Example: Poresi PF (A) made by Showa KDE], silica fiber (fiber diameter 7 μm, fiber length 12 mm) and 5000 ml of water with a home mixer for 1 minute. Paper was fired with a machine [Example: 25 cm square manufactured by Kumagai Riki Kogyo Co., Ltd.] to obtain a sheet (heat insulating material sheet) having a basis weight of 350 g / m ² . However, the composition ratio of attapulgite to inorganic fibers composed of attapulgite and silica fibers is set to 10 to 50%. That is, the composition ratio of attapulgite is 10% in Example 1, 20% in Example 2, 25% in Example 3, and 50% in Example 4.

[Comparative Example 1]
A slurry liquid in which paper pulp, silica fiber (fiber diameter: 7 μm, fiber length: 12 mm) and 5000 ml of water are dispersed for 1 minute with a home mixer is applied to a square sheet paper machine [Example: 25 cm square manufactured by Kumagai Riki Kogyo]. Paper sheeting was performed to obtain a sheet (insulation sheet) having a basis weight of 350 g / m ² . In this case, the composition ratio of paper pulp and silica fiber is 1: 9.

[Comparative Examples 2 and 3]
Square sheet paper made of slurry obtained by dispersing attapulgite mineral [Example: Poresi PF (A) made by Showa KDE], silica fiber (fiber diameter 7 μm, fiber length 12 mm) and 5000 ml of water with a home mixer for 1 minute. Paper was fired with a machine [Example: 25 cm square manufactured by Kumagai Riki Kogyo Co., Ltd.] to obtain a sheet (heat insulating material sheet) having a basis weight of 350 g / m ² . However, the composition ratio of attapulgite to inorganic fibers composed of attapulgite and silica fibers is set to less than 10% or more than 50%. That is, the composition ratio of attapulgite is 75% in Comparative Example 2 and 85% in Comparative Example 3.

  As can be seen from FIG. 1, the comparative example 1 obtained by mixing paper pulp and silica fibers with an organic binder exhibits a good bulk density, but the tensile strength after heating is reduced. The form cannot be kept large. And in the thing of the comparative examples 2 and 3 by paper making using the inorganic fiber which consists of an attapulgite and silica fiber with a composition ratio exceeding 50, there is no problem in particular in the fall of the tensile strength after a heating, and it uses as a heat insulating material. Although it is possible, there is a drawback that the bulk density is large.

On the other hand, the heat insulating material sheets of Examples 1 to 4 obtained by papermaking using inorganic fibers composed of attapulgite and silica fibers having a composition ratio of 10 to 50% are excellent in shape retention and are heated. The decrease in tensile strength is small, and the bulk density is 0.2 g / cm ² or less, and the heat insulation is excellent. Moreover, since no organic binder is used, no odor or smoke is produced during production, and it is environmentally friendly. In addition, there exists a tendency for tensile strength and bulk density to become large, so that the composition ratio of attapulgite is large.

  The heat insulating material 10 (refer FIG. 2) by this invention is electromagnetic induction heaters (or this), such as IH jar (electromagnetic induction rice cooker), IH cooking heater (electromagnetic induction heater), a microwave oven (electromagnetic induction cooker), for example. It is possible to use suitably for the heat insulation location in the (equipment containing).

The figure which shows the characteristic comparison table of each Example and each comparative example of a heat insulating material Principle diagram showing the method of manufacturing insulation Action diagram showing another example of paper making process

Explanation of symbols

11 Attapulgite 12 Ceramic fiber 13 Inorganic fiber a Mixing process b Paper making process

Claims (5)

  A heat insulating material made by papermaking using inorganic fibers comprising ceramic fibers and attapulgite.   The heat insulating material according to claim 1, wherein a composition ratio of the attapulgite to the inorganic fiber is set to 10 to 50%.   The heat insulating material according to claim 1 or 2, wherein the heat insulating material is used for a heat insulating portion in an electromagnetic induction heater.   A method for producing a heat insulating material, comprising: a mixing step of mixing ceramic fibers and attapulgite to create inorganic fibers; and a paper making step of making paper using the inorganic fibers.   In the said mixing process, the manufacturing rate of the heat insulating material of Claim 4 which sets the structural ratio with respect to the said inorganic fiber of the said attapulgite to 10 to 50%.

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