JP5763925B2 - Insulation manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a heat insulating material.

Conventionally, a heat insulating material mainly composed of inorganic fibers such as silica alumina fiber or alumina fiber using a papermaking method has been manufactured.
In a conventional heat insulating material manufacturing method as shown in Patent Document 1, after adding inorganic fibers into water, stirring and opening, silica sol or the like serving as a binder is added to water containing inorganic fibers, and inorganic particles are added. In addition, finally, a flocculant is added to agglomerate inorganic fibers, inorganic particles, silica sol and the like in water, and then a heat insulating material is obtained by filtration and dehydration.

Recently, however, in Europe, the use of heat insulating materials using inorganic fibers such as silica-alumina fibers is being regulated by the EU SVHC regulations, and the development of heat insulating materials that do not use these inorganic fibers is awaited. .

So-called biosoluble fibers are attracting attention as inorganic fibers that are outside the scope of regulations in Europe. Biosoluble fibers have the property of dissolving in physiological saline, so even if they are taken into the body, they are dissolved and discharged outside the body. Because.

In addition to the above-mentioned biosoluble fiber, rock wool is mentioned as a fiber that is outside the scope of regulations in Europe.

Japanese Patent Laid-Open No. 5-9083

However, biosoluble fibers and rock wool have different surface states from silica alumina fibers and the like. Therefore, when manufacturing a heat insulating material using a biosoluble fiber and rock wool, when using the conventional heat insulating material manufacturing method of Patent Document 1 described above, inorganic particles, silica sol and the like do not aggregate well, filtration, It turned out that dehydration etc. cannot be performed well. As a result, the conventional method for manufacturing a heat insulating material of Patent Document 1 has a problem that it is difficult to obtain a heat insulating material having a sufficiently high density and high strength.

The present invention has been made to solve such problems, and provides a heat insulating material that has sufficient density and strength and maintains sufficient strength even when used at high temperatures. Objective.

That is, in the method for producing a heat insulating material according to claim 1, after the cationic polymer and the inorganic fiber are put into water, the slurry in which the inorganic fiber and the cationic polymer are dispersed in water, Next, a cationic flocculant is added to the slurry to which the water-soluble inorganic binder is added, an anionic flocculant is further added, and an aggregate is produced. It is characterized by being put into a mold and dehydrated.

In the method for manufacturing a heat insulating material according to claim 1, first, inorganic fibers and a cationic polymer are dispersed in water. At this time, the inorganic fibers are opened in water. At this time, the inorganic fiber is considered to be negatively charged in water. It is considered that the negative charge is neutralized and the repulsive force is reduced by the cationic polymer clinging to the opened inorganic fibers that are negatively charged in water. For this reason, the fine particles constituting the water-soluble inorganic binder such as silica sol which plays a role as an adhesive to be added thereafter easily aggregate. As a result, flocs containing fine particles constituting inorganic fibers, a cationic polymer and a water-soluble inorganic binder can be formed with a cationic flocculant, and flocs can be agglomerated with an anionic flocculant to produce an aggregate. Thus, the entanglement between the fibers is improved by firmly agglomerating the fine particles constituting the inorganic fiber and the water-soluble inorganic binder, and the fine particles constituting the water-soluble inorganic binder adhere to the inorganic fiber, and the inorganic fibers are Can be tightly coupled. Therefore, a heat insulating material having sufficient density and strength and having sufficient strength even when used at a high temperature can be produced by dehydrating the obtained aggregate. Moreover, since the aggregate containing inorganic fibers can be sufficiently aggregated, dehydration molding can be performed in a short time, and a heat insulating material can be produced efficiently. The reason why the inorganic fibers are negatively charged is considered to be because the inorganic fibers containing silica and having SiOH groups release H ⁺ into SiO ⁻ in water. In addition, when the inorganic fiber dispersed in water has almost no charge, the addition of the cationic flocculant and the anionic flocculant causes the flocculant to adhere to these flocculants and can be made into a large flocculent as well. .

In the method for producing a heat insulating material according to claim 2, in the step of introducing the cationic polymer and the inorganic fiber into water, the cationic polymer is first introduced into water, and the cationic polymer is dispersed and / or dissolved in water. Then, the inorganic fiber is thrown into water and dispersed.
If the cationic polymer is not well dispersed and lumps remain, it is difficult to disperse and entangle the input fibers in the lumped cationic polymer, but the heat insulating material according to claim 2 In this production method, the cationic polymer is poured into water, sufficiently dispersed and / or dissolved, and then the inorganic fiber is introduced. Therefore, the negative polymer charged into the sufficiently dispersed positively charged cationic polymer is added. Insulating fibers having electric charges are more easily entangled, and a heat insulating material having sufficient density and strength can be manufactured.

In the method for producing a heat insulating material according to claim 3, since the cationic polymer is a cationized starch composed of a polymer having a predetermined size, the cationized starch having a positive charge having a predetermined size and sufficiently dispersed. Inorganic fibers having a mass charge are entangled with each other to form a lump of an appropriate size. Since the inorganic fibers having a negative charge attached to such cationized starch and the neutralized mass do not repel each other, they are more likely to aggregate in a later step.

In the method for manufacturing a heat insulating material according to claim 4, the inorganic fiber is a biosoluble fiber, rock wool, alumina fiber, silica-alumina fiber, or silica alumina zirconia fiber.
Moreover, in the manufacturing method of Claim 5, an inorganic fiber is a biosoluble fiber or rock wool.
In the present invention, even a biosoluble fiber and rock wool that have not been used in the past can form a sufficiently agglomerated floc by using the method of the present invention, and have sufficient density and strength. In addition, it is possible to produce a heat insulating material that maintains sufficient strength even when used at high temperatures.
In addition, even when a conventionally used alumina fiber, silica-alumina fiber, or silica alumina zirconia fiber is used, a sufficiently agglomerated floc can be formed by using the method of the present invention. A heat insulating material having a sufficient density and strength and having a sufficient strength even when used at a high temperature can be produced.

In the method for manufacturing a heat insulating material according to claim 6, the biosoluble fiber contains an alkali metal compound or an alkaline earth metal compound.
Accordingly, the biosoluble fiber in the heat insulating material has a property of being dissolved in physiological saline, and even if it is taken into the human body, it is dissolved and discharged out of the body. Therefore, the heat insulating material using the biosoluble fiber has an excellent feature that it is excellent in safety to the human body.

In the method for producing a heat insulating material according to claim 7, before adding the water-soluble inorganic binder, the cationic polymer and the inorganic fiber are poured into water, and then the inorganic particles are added.
Thus, before adding the water-soluble inorganic binder, after adding the cationic polymer and the inorganic fiber into the water and then adding the inorganic particles, it is also added first and charged negatively in the water. It is considered that the negative charge is neutralized and the repulsive force is reduced by the cationic polymer clinging to the opened inorganic fibers. Therefore, the inorganic particles to be added thereafter and the fine particles constituting the water-soluble inorganic binder easily aggregate, and a heat insulating material in which the inorganic particles are firmly attached to the inorganic fibers in the heat insulating material can be obtained.

In the method for manufacturing a heat insulating material according to claim 8, the inorganic particles are at least one selected from the group consisting of bentonite, titanium oxide, silica powder, and alumina powder.
When the heat insulating material contains bentonite, silica powder, alumina powder, etc., particles such as bentonite, silica powder, alumina powder are mixed with fine particles constituting the water-soluble inorganic binder, bentonite, silica powder, alumina powder, etc. It plays the role of an adhesive together with the fine particles constituting the water-soluble inorganic binder. Therefore, these particles adhere firmly to the fibers and adhere the inorganic fibers together, and remain in the obtained heat insulating material, thereby improving the strength of the heat insulating material. Furthermore, the characteristic according to the function of each inorganic particle can be provided to a heat insulating material.
Specifically, the mechanical strength is improved when the heat insulating material has bentonite. When the heat insulating material contains titanium oxide, radiant heat can be scattered, and the heat insulating performance is improved. When the heat insulating material contains silica powder, the heat insulating performance is improved. When the heat insulating material contains alumina powder, the heat resistance performance is improved.

In the manufacturing method of the heat insulating material of Claim 9, the addition amount of the bentonite with respect to 100 weight part of inorganic fibers is 2-40 weight part.
Since the amount of bentonite added to 100 parts by weight of the inorganic fibers is in the above range, the bentonite functions appropriately as an adhesive and bonds the inorganic fibers to each other at least partially. Therefore, it can be set as the heat insulating material which has further higher intensity | strength. When the content of bentonite is less than 2 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of bentonite that functions as an adhesive is small, so that the strength of the heat insulating material is not sufficiently increased. On the other hand, when the content of bentonite exceeds 40 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of bentonite in the slurry is large. The drainage at that time is lowered, and the filtration takes time, so the productivity is lowered.

In the manufacturing method of the heat insulating material of Claim 10, the addition amount of the titanium oxide with respect to 100 weight part of inorganic fibers is 10-70 weight part.
Since the addition amount of titanium oxide with respect to 100 parts by weight of the inorganic fibers is in the above range, heat radiation can be scattered, and further high heat insulation can be imparted to the heat insulating material. When the content of titanium oxide is less than 10 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of titanium oxide that scatters heat radiation is small, and therefore an effect of further improving the heat insulation cannot be expected. On the other hand, when the content of titanium oxide exceeds 70 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of titanium oxide in the slurry is large. The drainage during dehydration is reduced. Therefore, productivity is reduced.

In the manufacturing method of the heat insulating material of Claim 11, the addition amount of the water-soluble inorganic binder converted into solid content with respect to 100 weight part of inorganic fibers is 0.1-20 weight part.
The fine particles (colloidal silica, colloidal alumina, etc.) constituting the water-soluble inorganic binder serve as an adhesive by adhering to the inorganic fibers constituting the heat insulating material. Therefore, inorganic fibers adhere to each other at a part thereof, whereby the heat insulating material can maintain a predetermined shape and maintain strength.

Since the addition amount of the water-soluble inorganic binder converted to the solid content with respect to 100 parts by weight of the inorganic fiber is in the above range, the amount of fine particles functioning as an adhesive is appropriate, and a heat insulating material having sufficient density and strength is manufactured. be able to. If the amount of water-soluble inorganic binder converted to solid content is less than 0.1 parts by weight with respect to 100 parts by weight of inorganic fibers, the amount of fine particles functioning as an adhesive is insufficient and the strength of the heat insulating material is reduced. To do. On the other hand, when the addition amount of the water-soluble inorganic binder converted to the solid content exceeds 20 parts by weight with respect to 100 parts by weight of the inorganic fibers, the amount of fine particles serving as an adhesive becomes excessive and segregates on the inorganic fibers. This makes the heat insulating material non-uniform in density. Therefore, in the part where the density of a heat insulating material is high, since the heat insulating performance falls, the heat insulating performance of a heat insulating material falls as a whole. Further, since the amount of fine particles present in the water increases, the filterability is lowered, and it takes time to filter. As a result, productivity decreases.

FIG. 1 is an explanatory view schematically showing each step in the manufacturing method according to the first embodiment of the present invention. FIG. 2 is an explanatory view schematically showing each step in the manufacturing method according to the second embodiment of the present invention.

The present inventors examined whether the same method can be applied when manufacturing the heat insulating material which is one field of the ceramic industry according to the present invention with reference to the following manufacturing method in the field of the paper industry.
The production method disclosed in Japanese Patent Laid-Open No. 1-92498 is a method in which cationized starch, bentonite and colloidal silicic acid (silica sol) are added to a paper slurry and paper is made in a neutral region.

Also disclosed is a method of making a paper by adding a sulfuric acid band and a high molecular weight low-density polymer to the stock slurry.

The manufacturing method disclosed in the pamphlet of International Publication No. 2006/070853 includes a copolymer containing a cationic radical polymerizable monomer and a nonionic radical polymerizable monomer in a paper slurry, and a cationic radical In this method, a copolymer containing a polymerizable monomer, an anionic radical polymerizable monomer, and a nonionic radical polymerizable monomer is added to make paper.

After preparing a slurry of inorganic fibers such as silica alumina fiber, alumina fiber, biosoluble fiber, rock wool, etc. Tried to do.

However, even when referring to the method described in JP-A-1-92498 and the method using the above-described sulfuric acid band and high molecular weight low-density polymer, the biosoluble fiber and rock wool hardly aggregate. Therefore, it has been found that there is a problem in that it is difficult to perform filtration, dehydration, etc., and it is difficult to manufacture a sufficiently high density heat insulating material.

Furthermore, when referring to the method described in the pamphlet of International Publication No. 2006/070853, the biosoluble fiber and the rock wool are aggregated but weakly entangled with each other and obtained by filtration and dehydration. It was found that the molded body has a problem that it has low strength and is difficult to use as a heat insulating material.

The inventors of the present invention have made extensive studies on a method for producing a heat insulating material having a sufficient density and strength and maintaining a sufficient density even when used at a high temperature. And the manufacturing method of the heat insulating material of this invention was completed.

(First embodiment)
Hereinafter, 1st embodiment which is one Embodiment of the manufacturing method of the heat insulating material of this invention is described.
Drawing 1 is an explanatory view showing each process in a manufacturing method of a heat insulating material concerning a first embodiment of the present invention.

In the method for manufacturing a heat insulating material according to the first embodiment of the present invention, after the cationic polymer is introduced into water and dispersed and / or dissolved, the inorganic fiber is introduced and dispersed in water to form a slurry. A water-soluble inorganic binder is added to the slurry, then a cationic flocculant is added to the slurry to which the water-soluble inorganic binder has been added, and an anionic flocculant is further added.

As shown in FIG. 1, a process in which a cationic polymer is introduced into water and dispersed and / or dissolved, and then the inorganic fiber is introduced and dispersed in water to form a slurry is defined as a first process. The step of adding the water-soluble inorganic binder is the second step, the step of adding the cationic flocculant to the slurry to which the water-soluble inorganic binder is added is the third step, and then the step of adding the anionic flocculant Is the fourth step.

First, the first step will be described.
In the first step, the cationic polymer is introduced into water and dispersed and / or dissolved, and then the inorganic fiber is introduced and dispersed in water to form a slurry.

First, the cationic polymer is poured into water and stirred well to disperse and / or dissolve in water.
The method for dispersing or dissolving the cationic polymer in water is not particularly limited. First, the cationic polymer is added to a predetermined amount of water so that the concentration becomes 0.5 to 5% by weight. The cationic polymer is uniformly dispersed and / or dissolved in water by stirring for about 30 minutes.

The liquid prepared in this manner can be dispersed relatively well by being introduced into a tank filled with water for adding fibers and stirred. At this time, it is preferable that 1-20 weight part of cationic polymers exist in conversion of solid content with respect to 100 weight part of inorganic fiber thrown in later. The concentration of the cationic polymer in water is 0.01 to 0.5% by weight.
When the amount of the cationic polymer is less than 1 part by weight in terms of solid content with respect to 100 parts by weight of the inorganic fiber, the addition amount of the cationic polymer is small, so that the inorganic fiber and other additive substances are sufficiently aggregated in the subsequent process. do not do. On the other hand, even if the amount of the cationic polymer exceeds 20 parts by weight in terms of solid content with respect to 100 parts by weight of the inorganic fiber, the coagulation effect between the inorganic fiber and other additive substances is not improved so much and it is not economical.

Thereafter, inorganic fibers are added and stirred.
The input amount of the inorganic fiber is preferably 3 to 50 parts by weight with respect to 1000 parts by weight of water.
As a result, the inorganic fiber is charged into the water in which the cationic polymer is uniformly dispersed and is negatively charged. Therefore, the cationic polymer and the inorganic fiber come close to each other, and the cationic polymer is entangled with the inorganic fiber.
If the input amount of the inorganic fiber is less than 3 parts by weight, the input amount of the inorganic fiber is too small, so that the amount of the obtained heat insulating material is reduced and the productivity is lowered, while the input amount of the inorganic fiber is 50 parts by weight. If it exceeds, the amount of the inorganic fiber with respect to water becomes too large, and it becomes difficult to uniformly stir the additive substance such as the cationic polymer charged by stirring or the like.
The stirring time after adding the inorganic fiber and adding the water-soluble inorganic binder in the second step is preferably 30 seconds to 30 minutes. When the stirring time is less than 30 seconds, the inorganic fibers are not uniformly dispersed in water, and good aggregation cannot be performed. On the other hand, even if the stirring time exceeds 30 minutes, the effect of uniformly dispersing inorganic fibers by stirring does not increase, which is not economical.

The cationized polymer is not particularly limited, and any cationic polymer can be used.
Examples of the cationized polymer include cationic acrylamide, cationized starch, and cationized modified acrylic copolymer.
Specific examples of the cationized polymer include Percoll (cationic acrylamide) manufactured by Allied Colloid, Polystron 705 (cationic acrylamide) manufactured by Arakawa Chemical Industries, Polystron Arafix DC-R (cationic acrylamide), Examples include Phyrex RC-104 (cation-modified acrylic copolymer) manufactured by Meisei Chemical Co., Ltd.

Of these, cationized starch is preferred. The cationized starch refers to starch having a cationic property. Starch is a natural polymer in which a number of α-glucose molecules are polymerized by glycosidic bonds, and in the present invention, this starch is cationized by using a conventional method so as to be cationic.

Examples of the cationization method include a method of treating raw material starch with a cationizing agent. Examples of the cationizing agent include tertiary amines such as diethylaminoethyl chloride and quaternary ammonium salts such as 3-chloro-2-hydroxypropyltrimethylammonium chloride.

The raw material starch to be cationized is not particularly limited. Examples include starch, gurumannan, and galactan. Of these, potato is preferred.

Specific examples of the cationized starch include, for example, Mermaid 350 manufactured by Shikishima Starch.

As an inorganic fiber used with the manufacturing method of the heat insulating material of this embodiment, biosoluble fiber, rock wool, an alumina fiber, a silica-alumina fiber, a silica alumina zirconia fiber etc. are mentioned, for example.
Among these inorganic fibers, in the embodiment of the present invention, it can be effectively used particularly for biosoluble fibers or rock wool.

As for the minimum of the average fiber diameter of the inorganic fiber used with the manufacturing method of the heat insulating material of this embodiment, 1 micrometer is desirable. On the other hand, the upper limit of the average fiber diameter of the inorganic fibers is desirably 10 μm. As for the average fiber diameter of the said inorganic fiber, 2-8 micrometers is more desirable.
When the average fiber diameter is less than 1 μm, it is difficult to produce such inorganic fibers. On the other hand, when the average fiber diameter of the inorganic fibers exceeds 10 μm, the inorganic fibers become brittle and the strength of the formed heat insulating material is difficult to be obtained.

The biosoluble fiber refers to a fiber having a property of being dissolved in physiological saline. As for the inorganic fiber used for the manufacturing method of the heat insulating material of this embodiment, it is desirable that the solubility with respect to the physiological saline at 37 degreeC is 300 ppm (0.03 weight%) or more. This is because an inorganic fiber having a solubility of 300 ppm (0.03% by weight) or more dissolves rapidly under physiological conditions, so that the risk of the inorganic fiber being taken into the living body can be reduced.

The biosoluble fiber preferably includes at least one selected from the group consisting of an alkali metal compound, an alkaline earth metal compound, and a boron compound, and includes an alkali metal compound or an alkaline earth metal compound. More preferred.

Examples of the alkali metal compound include sodium or potassium oxides or salts, and examples of the alkaline earth metal compound include magnesium, calcium, or barium oxides or salts. Examples of the boron compound include boron oxides and salts. Fibers obtained by adding sodium, potassium, magnesium, calcium, barium, boron oxides or salts to silica, alumina, silica alumina, glass, etc. used as inorganic fiber materials should be biosoluble. it can.
The biosoluble fiber of the present embodiment preferably contains at least 15 to 30% by weight of magnesium oxide (MgO), or contains at least 15 to 35% by weight of calcium oxide (CaO).

The biosoluble fiber used in the heat insulating material manufacturing method of the present embodiment preferably contains 60 to 85% by weight of silica in addition to the inorganic compound, and more preferably contains 70 to 80% by weight. When the content of silica in the biosoluble fiber is less than 60% by weight, the strength of the biosoluble fiber tends to be weak. On the other hand, when the content of silica in the biosoluble fiber exceeds 85% by weight, the content of the inorganic compound in the biosoluble fiber decreases, so that the biosolubility is likely to be lowered.
Examples of the biosoluble fiber include FF-E and BIOSOL manufactured by NICHIAS Corporation, SW607 and SW607HT manufactured by Shin Nippon Thermal Ceramics Co., Ltd., Isofrax and Insulfrax manufactured by Isolite Industry Co., Ltd., and the like.

Rock wool is generally blast furnace slag or basalt, other natural rocks, etc. as a main raw material, melted at a high temperature of 1500-1600 ° C. in a cupola or electric furnace, or at the same high temperature after leaving the blast furnace This refers to an artificial mineral fiber that is made into a fiber by letting molten slag that has been kept warm to flow out from the bottom of the furnace and blowing it away with centrifugal force.

In the heat insulating material manufacturing method according to the present embodiment, silica (SiO ₂ ) is 30 to 50 wt%, alumina (Al ₂ O ₃ ) is 10 to 20 wt%, calcium oxide (CaO) is 25 to 45 wt%, It is desirable to use rock wool containing 3 to 10% by weight of magnesium oxide (MgO).
Examples of rock wool include Pacific mineral fiber manufactured by Taiheiyo Material Co., Ltd.

The silica-alumina fiber used in the method for manufacturing a heat insulating material according to this embodiment preferably has an alumina / silica composition ratio of 40/60 to 70/30. The silica-alumina fiber can be produced by melting a silica-alumina mixture at a high temperature and fiberizing it by a spinning method or a blowing method.
When the content of alumina in the silica-alumina fiber is less than 40% by weight, the amount of alumina having excellent heat resistance is reduced, so that the heat resistance of the heat insulating material is lowered. On the other hand, when the content of alumina in the silica-alumina fiber exceeds 70% by weight, the melting temperature of the silica-alumina fiber becomes high, so that it is difficult to produce by the spinning method or the blowing method. A silica-alumina fiber having an alumina content exceeding 70% by weight and a silica content less than 30% by weight is generally referred to as an alumina fiber. Also in the present invention, an alumina fiber having an alumina content exceeding 70% by weight and a silica content less than 30% by weight is referred to as an alumina fiber.

As for the silica alumina zirconia fiber used with the manufacturing method of the heat insulating material concerning this embodiment, it is preferred that the composition ratio of silica / alumina / zirconia is 45-55 / 25-35 / 10-20.
Heat resistance is further improved by adding zirconia to silica alumina fibers. When the composition ratio of zirconia is less than 10% by weight, mullite precipitates and heat resistance is poor. On the other hand, when the composition ratio of zirconia exceeds 20% by weight, the amount of zirconia crystals precipitated in the fiber increases and the fiber becomes brittle.

Next, the second step will be described.
In the second step, a water-soluble inorganic binder is added to the slurry into which the cationic polymer and inorganic fibers have been added and stirred.

The water-soluble inorganic binder is not particularly limited, and examples thereof include silica sol and alumina sol.
The water-soluble inorganic binder is added to adhere inorganic fibers to each other, and fine particles such as colloidal silica and colloidal alumina in an aqueous solution adhere to the inorganic fibers constituting the heat insulating material. Acts as an adhesive. Therefore, inorganic fibers adhere to each other at a part thereof, thereby maintaining a predetermined shape of the heat insulating material.
The stirring time from the addition of the water-soluble inorganic binder to the addition of the cationic flocculant in the third step is preferably 30 seconds to 5 minutes. When the stirring time is less than 30 seconds, the water-soluble inorganic binder is not uniformly dispersed in water, and good aggregation cannot be performed. On the other hand, even if the stirring time exceeds 5 minutes, the uniform dispersion effect of the water-soluble inorganic binder by stirring does not increase and is not economical.

In the first step, it is considered that the negative charge is neutralized and the repulsive force is reduced by the cationic polymer clinging to the added negatively charged inorganic fiber. Therefore, the fine particles constituting the water-soluble inorganic binder such as silica sol added in the second step are aggregated and easily adhere to the inorganic fibers.

Although the addition amount of the water-soluble inorganic binder converted into solid content with respect to 100 weight part of inorganic fibers is not particularly limited, it is preferably 0.1 to 20 weight part in terms of solid content.
Fine particles (colloidal silica, colloidal alumina, etc.) constituting the water-soluble inorganic binder serve as an adhesive by adhering to the inorganic fibers. Therefore, the inorganic fibers are bonded to each other at a part thereof, whereby the heat insulating material can maintain a predetermined shape and keep the strength.
When the addition amount of the water-soluble inorganic binder converted to the solid content with respect to 100 parts by weight of the inorganic fiber is in the above range, the amount of fine particles functioning as an adhesive is appropriate, and a heat insulating material having sufficient density and strength is produced. be able to. If the amount of water-soluble inorganic binder converted to solid content is less than 0.1 parts by weight with respect to 100 parts by weight of inorganic fibers, the amount of fine particles functioning as an adhesive is insufficient and the strength of the heat insulating material is reduced. To do. On the other hand, when the addition amount of the water-soluble inorganic binder converted to the solid content exceeds 20 parts by weight with respect to 100 parts by weight of the inorganic fibers, the amount of fine particles serving as an adhesive becomes excessive and segregates on the inorganic fibers. It becomes easy to do. Therefore, the density of the heat insulating material becomes non-uniform. In a portion where the density of the heat insulating material is high, the heat insulating performance is lowered, so that the heat insulating performance of the heat insulating material is lowered as a whole. In addition, since the amount of fine particles present in the water increases, the filterability is reduced and the filtration takes time, so the productivity is reduced.

When silica sol is used as the water-soluble inorganic binder, the amount of silica sol added to the solid content with respect to 100 parts by weight of the inorganic fiber is preferably 0.5 to 20 parts by weight, and more preferably 2 to 8 parts by weight. When the amount of silica sol converted to solid content is less than 0.5 parts by weight with respect to 100 parts by weight of the inorganic fibers, the amount of fine particles functioning as an adhesive is insufficient, and the strength of the heat insulating material decreases. On the other hand, when the addition amount of silica sol converted to solid content exceeds 20 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of fine particles that play the role of the adhesive becomes too large and segregates on the inorganic fiber. For this reason, the density of the heat insulating material becomes non-uniform. In a portion where the density of the heat insulating material is high, the heat insulating performance is lowered, so that the heat insulating performance of the heat insulating material is lowered as a whole. In addition, since the amount of fine particles present in the water increases, the filterability is reduced and the filtration takes time, so the productivity is reduced.
On the other hand, when alumina sol is used as the water-soluble inorganic binder, the amount of alumina sol converted to solid content with respect to 100 parts by weight of inorganic fibers is preferably 0.1 to 20 parts by weight, and 0.5 to 4 parts by weight. More preferred. If the amount of alumina sol converted to solid content is less than 0.1 parts by weight with respect to 100 parts by weight of inorganic fibers, the amount of fine particles functioning as an adhesive is insufficient, and the strength of the heat insulating material is reduced. On the other hand, when the addition amount of silica sol converted to solid content exceeds 20 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of fine particles that play the role of the adhesive becomes too large and segregates on the inorganic fiber. For this reason, the density of the heat insulating material becomes non-uniform. Therefore, in the part where the density of a heat insulating material is high, since the heat insulating performance falls, the heat insulating performance of a heat insulating material falls as a whole. Further, since the amount of fine particles present in the water increases, the filterability is lowered, and it takes time to filter. Therefore, productivity is reduced.

Next, the third step will be described.
In the third step, a cationic flocculant is added to the slurry to which the cationic polymer, inorganic fibers and water-soluble inorganic binder are added.
By adding a cationic flocculant, flocs containing fine particles constituting inorganic fibers, a cationic polymer, and a water-soluble inorganic binder can be formed.
The stirring time from the addition of the cationic flocculant to the addition of the anionic flocculant in the fourth step is preferably 30 seconds to 5 minutes. When the stirring time is less than 30 seconds, the cationic flocculant is not uniformly dispersed in water, and good flocculation cannot be performed. On the other hand, even if the stirring time exceeds 5 minutes, the effect of uniform dispersion of the cationic flocculant by stirring does not increase, which is not economical.

The addition amount of the cationic flocculant with respect to 100 parts by weight of the inorganic fiber is not particularly limited, but is preferably 0.5 to 10.0 parts by weight and more preferably 1 to 2 parts by weight in terms of solid content.
If the amount of the cationic flocculant added relative to 100 parts by weight of the inorganic fiber is less than 0.5 parts by weight in terms of solid content, the amount of the cationic flocculant is small, so that the fine particles constituting the inorganic fiber, the cationic polymer and the water-soluble inorganic binder It becomes difficult to form a floc containing. On the other hand, even if the addition amount of the cationic flocculant with respect to 100 parts by weight of the inorganic fiber exceeds 10.0 parts by weight in terms of solid content, the effect of forming flocs is not much changed, and the organic component is not contained in the obtained heat insulating material. When it is used too much as a heat insulating material, decomposition of an organic component or the like occurs.

The cationic flocculant is not particularly limited, and examples thereof include cationic acrylamide, cationized starch, and cationized modified acrylic copolymer.

Specific examples of the cationic flocculant include Mermaid 350 (cationized starch) manufactured by Shikishima Starch, Percoll (cationic acrylamide) manufactured by Allied Colloid, Polystron 705 (cationic acrylamide) manufactured by Arakawa Chemical Industries, Ltd. Examples include TRON ARAFIX DC-R (cationic acrylamide), and FIREX RC-104 (cation-modified acrylic copolymer) manufactured by Meisei Chemical Industry Co., Ltd.

Next, the fourth step will be described.
In the fourth step, an anionic flocculant is added to the slurry to which the cationic polymer, inorganic fibers and water-soluble inorganic binder, and cationic flocculant are added.
By adding the anionic flocculant, the positively charged floc containing the fine particles constituting the inorganic fiber, the cationic polymer and the water-soluble inorganic binder, and the cationic flocculant can be aggregated by the anionic flocculant having the opposite charge. .
The stirring time until filtration in the fourth step is preferably 30 seconds to 5 minutes.
When the stirring time is less than 30 seconds, the anionic flocculant is not uniformly dispersed in water, and good agglomeration cannot be performed. On the other hand, even if the stirring time exceeds 5 minutes, the effect of uniform dispersion of the anionic flocculant by stirring does not increase, which is not economical.

Examples of the anionic flocculant include anionic polyacrylamide and an acrylic copolymer.
Specific examples of the anionic flocculant include, for example, Polystron 117 (anionic polyacrylamide) manufactured by Arakawa Chemical Industries, Polyaclon (anionic polyacrylamide) manufactured by Seiko PMC, and Pyrex M manufactured by Meisei Chemical Industry Co., Ltd. (Acrylic copolymer) and the like.

The addition amount of the anionic flocculant with respect to 100 parts by weight of the inorganic fiber is not particularly limited, but is preferably 0.1 to 10 parts by weight in terms of solid content, and 0.1 to 2 parts by weight in terms of solid content. More preferred.
If the addition amount of the cationic flocculant relative to 100 parts by weight of the inorganic fiber is less than 0.1 part by weight in terms of solid content, the amount of the anionic flocculant is small, so that the fine particles constituting the inorganic fiber, the cationic polymer, and the water-soluble inorganic binder And the floc containing the cationic flocculant is sufficiently aggregated to make it difficult to form an aggregate. On the other hand, even if the addition amount of the anionic flocculant with respect to 100 parts by weight of the inorganic fiber exceeds 10 parts by weight in terms of solid content, the effect of forming flocs does not change so much, and the obtained heat insulating material has a large organic content. When it is used as a heat insulating material, decomposition of organic components occurs, which leads to a decrease in strength, which is not preferable.

A slurry in which an aggregate containing inorganic fibers, a cationic polymer, fine particles constituting a water-soluble inorganic binder, a cationic flocculant and an anionic flocculant is formed in this manner is poured into a mold, and a small amount is obtained. A molded heat insulating material having a predetermined shape containing the moisture is formed.
Then, in order to remove the water | moisture content in a shaping | molding heat insulating material, it dries and processes into a predetermined shape, and a heat insulating material is completed.

The obtained heat insulating material sucks and filters sufficiently agglomerated aggregates including inorganic fiber, cationic polymer, fine particles constituting water-soluble inorganic binder, cationic aggregating agent and anionic aggregating agent. And at least a part of the inorganic fibers are firmly bonded via the fine particles constituting the water-soluble inorganic binder, thereby providing a heat insulating material having strength required as a heat insulating material.

Specifically, the density of the heat insulating material is preferably 0.2 to 0.5 g / cm ² , the strength thereof is 0.2 to 3 MPa, and the thermal conductivity is 0.08 to 0.15 W / m · K (600 ° C.) is preferred. The thermal conductivity is obtained by a hot wire method. The hot wire method is based on the following principle. That is, if a thin heater wire is linearly stretched at the center of a homogeneous sample in a shape that can be regarded as an infinite cylinder and a constant electric power (heat amount) is continuously applied to the heater wire, the heater temperature rises exponentially. If the time axis is taken on a logarithmic scale, the temperature rise curve becomes linear, and the thermal conductivity can be obtained from this slope. Specifically, the thermal conductivity can be determined by a hot wire method using QTM-580 manufactured by Kyoto Electronics Industry Co., Ltd.

Hereafter, it enumerates about the effect of the manufacturing method of the heat insulating material of 1st embodiment of this invention.
(1) In the method for manufacturing a heat insulating material according to the present embodiment, first, a cationic polymer is dispersed and / or dissolved in water, and then inorganic fibers are introduced into water. As a result, the cationic polymer is dispersed or dissolved in water. On the other hand, it is considered that the input inorganic fiber is opened in water and the inorganic fiber is negatively charged in water. For this reason, the cationic polymer clings to the opened inorganic fiber that is negatively charged in water, the negative charge is neutralized, and the repulsive force is reduced. For this reason, the fine particles constituting the water-soluble inorganic binder such as silica sol which plays a role as an adhesive to be added thereafter easily aggregate. Therefore, a floc containing fine particles constituting inorganic fibers, a cationic polymer and a water-soluble inorganic binder can be formed with the cationic flocculant, and the flocs can be aggregated with the anionic flocculant. Thus, the entanglement between the fibers is improved by firmly agglomerating the fine particles constituting the inorganic fiber and the water-soluble inorganic binder, and the fine particles constituting the water-soluble inorganic binder adhere to the inorganic fiber, and the inorganic fibers are Glue firmly. Therefore, by performing filtration, dehydration, etc., a heat insulating material having a sufficient density and strength and having sufficient strength even when used at a high temperature can be produced. Moreover, since the aggregate containing inorganic fibers is sufficiently aggregated, dehydration molding can be performed in a short time, and a heat insulating material can be produced efficiently.

(2) In the manufacturing method of the heat insulating material of this embodiment, the heat insulating material containing a biosoluble fiber can be manufactured. The biosoluble fiber in the heat insulating material has a property of dissolving in physiological saline, and even if it is taken into the human body, it is dissolved and discharged out of the body. Therefore, the heat insulating material using the biosoluble fiber has an excellent feature that it is excellent in safety to the human body.

(3) In the method for producing a heat insulating material of the present embodiment, since a slurry entangled from inorganic fibers and a cationic polymer is first prepared using a cationic polymer, the negative charge of the inorganic fibers is easily neutralized, Compared with the prior art, it is easier to form an aggregate containing inorganic fibers and water-soluble inorganic binder in a later step. Accordingly, it is possible to manufacture not only a biosoluble fiber but also a heat insulating material using rock wool. Furthermore, a heat insulating material using conventionally used alumina fiber, silica-alumina fiber, and silica alumina zirconia fiber can also be produced.

Examples that more specifically disclose the first embodiment of the present invention are shown below, but the present invention is not limited to these examples.

Example 1
First, 1 part by weight of cationized starch (Mermaid 350 made by Shikishima Starch) was added to 99 parts by weight of water, and the mixture was stirred well for about 60 minutes to prepare diluted water in which the cationized starch was diluted to 1% by weight. .

Next, after adding 9900 parts by weight of water to the tank, adding the diluted water prepared in the above step and stirring, biosoluble fiber (Biol, manufactured by NICHIAS Corporation, SiO ₂ : 73% by weight, CaO: 25% by weight) %, Al ₂ O ₃ : 2% by weight, MgO: less than 1% by weight, average fiber diameter: 4.0 μm) was added, and the mixture was stirred well for 1 minute.

Next, 16.7 parts by weight (5.0 parts by weight in terms of solid content) of silica sol (Snowtex 30 manufactured by Nissan Chemical Industries, Ltd. (SiO ₂ concentration: 30% by weight)) was added and stirred again for 1 minute. .

Next, 20 parts by weight (2.0 parts by weight in terms of solid content) of a cationic flocculant (Polystron 705 manufactured by Arakawa Chemical Industries) was added and stirred for 1 minute, and then an anionic flocculant (Meisei Chemical Industry Co., Ltd.). 3 parts by weight (manufactured Phyrex M) (0.3 parts by weight in terms of solid content) was added, stirred for 1 minute, and then allowed to stand for 10 minutes to produce an aggregate.

Subsequently, a slurry containing the formed aggregates was poured into a mold for dehydration, and dehydrated molding was performed to produce a molded heat insulating body containing moisture.
Then, after drying the shaping | molding heat insulating body containing a water | moisture content at 105 degreeC, it cut and manufactured the heat insulating material. Table 1 shows the weight (parts by weight) of added substances such as added cationized starch.

Moreover, the supernatant liquid of the slurry at the time of producing the aggregate was collected, and the transparency of the supernatant liquid was measured to evaluate the cohesiveness of the slurry.
The transparency of the supernatant was measured by determining the absorbance of the supernatant as follows.
That is, first, using deionized water, it was put into a cell having an optical path length of 10 mm, and the intensity I ₀ of the transmitted light by applying light of 650 nm was measured, and this was used as a baseline.
Next, the supernatant of the slurry was put into a cell having an optical path length of 10 mm, and the intensity I of the transmitted light was measured in the same manner by applying light of 650 nm, and the absorbance was obtained.
The absorbance A _{λ at} this time is expressed by the following equation (1). Table 2 shows the measurement results of the absorbance of the supernatant of the slurry.
A _λ = −log ₁₀ I / I ₀ (1)

(Examples 2 and 3)
Cationic starch, silica sol, cationic flocculant and anionic flocculant, as in Example 1, except that the amounts of cationized starch, biosoluble fiber, silica sol, cationic flocculant and anionic flocculant were changed Was used to agglomerate the inorganic fibers introduced into the water and dehydrated to produce a heat insulating material.
Further, as in Example 1, the cohesiveness of the slurry was evaluated by determining the absorbance of the supernatant of the slurry. Table 1 shows the weight (parts by weight) of the added substance such as cationized starch, and Table 2 shows the measurement results of the absorbance of the supernatant of the slurry. In Examples 1 to 3, the amount of cationized starch added was varied in the range of 1 to 20 parts by weight.

(Comparative Example 1)
Except that the cationized starch was not added in the first step, in the same manner as in Example 1, the silica fiber, the cationic flocculant and the anionic flocculant were used to agglomerate the inorganic fibers thrown into water and dehydrated. A heat insulating material was manufactured by molding.
Further, as in Example 1, the cohesiveness of the slurry was evaluated by determining the absorbance of the supernatant of the slurry. Table 1 shows the weight (parts by weight) of the added substance such as cationized starch, and Table 2 shows the measurement results of the absorbance of the supernatant of the slurry.

(Evaluation of cohesiveness by dehydration test of aggregates)
Evaluation of cohesiveness in Examples 1 to 3 and Comparative Example 1 was performed by performing a dehydration test of the aggregate.
Specifically, silica sol, cationic flocculant, etc. were used under the same conditions as in Examples 1 to 3 and Comparative Example 1 except that 200 ml of industrial water was placed in a beaker and 2 g of inorganic fiber (biosoluble fiber) was used. The added substance was added and stirred to form aggregates, and then stirred for 10 minutes to break the flocs with weak aggregation. The slurry in this state is designated as Solution 1.

A filter paper was put on the suction port of the aspirator, and the solution 1 was charged. The start of charging was set to 0 second, and the suction was continued until the floc remained on the filter paper and completely drained out of water. The suction was terminated when the water was completely drained and the sound of air was sucked. The time during suction (the time from the start of charging until the sound of sucking air) was recorded as the dehydration time.
The measurement results of the dehydration time are shown in Table 2.

(Evaluation of thermal insulation)
(1) Density of heat insulating material The density of the heat insulating material was calculated from the volume and weight of the heat insulating material obtained in Example 2 and Comparative Example 1. The results are shown in Table 2.

(2) Measurement of bending strength of heat insulating material The bending strength of the heat insulating material obtained in Example 2 and Comparative Example 1 was measured by the following method.
First, the obtained heat insulating material was cut into a thickness of 25 mm, a width of 50 mm, and a length of 200 mm with a band saw to obtain a sample for measuring bending strength.
Next, using a measuring machine of Instron 5567, a bending strength test was performed by a three-point bending with a crosshead speed of 10 mm / min, a span of 150 mm, and the maximum load (N) until the heat insulating material was broken was measured.
The bending strength is calculated by the following equation (2).
Bending strength (MPa) = 3WL / 2b × h ² (2)
Where W is the maximum load (N), L is the span width (150 mm), b is the sample width (50 mm), and h is the sample thickness (25 mm).
The results are shown in Table 2.

As is clear from Tables 1 and 2, in the case of Examples 1 to 3, since the cationized starch was added first, Comparative Example 1 in which the cationized starch was not added (the absorbance of the supernatant was 0. 0). As compared with the case of 147), the absorbances of the supernatants of Examples 1 to 3 are as low as 0.061, 0.005, and 0.077, and the supernatant is transparent. Since the supernatant is transparent, it can be seen that in Examples 1 to 3, they are well aggregated. Accordingly, the dehydration time of Examples 1 to 3 is 19 seconds, 26 seconds, and 1 minute 5 seconds, respectively, compared to 1 minute 31 seconds of Comparative Example 1, and the dehydration work should be performed efficiently. You can see that The density of the thermal insulating material of Example 2 is higher than the density of 0.25 g / cm ³ of the heat insulating material of Comparative Example 1 and 0.35 g / cm ^3, flexural strength of Example 2, and 2.01MPa The bending strength of Comparative Example 1 is higher than 0.19 MPa. Therefore, in the case of Examples 1 to 3, it is considered that the density of the obtained heat insulating material is higher and the strength is higher than in the case of Comparative Example 1.
(Second embodiment)
Hereinafter, 2nd embodiment which is one Embodiment of the manufacturing method of the heat insulating material of this invention is described.
FIG. 2 is explanatory drawing which shows each process in the manufacturing method of the heat insulating material which concerns on 2nd embodiment of this invention.

In the heat insulating material manufacturing method according to the second embodiment of the present invention, an inorganic particle adding step is inserted between the first step and the second step of the heat insulating material manufacturing method according to the first embodiment of the present invention. This is different from the first embodiment of the present invention.

That is, in the second embodiment of the present invention, after the cationic polymer is charged into water, dispersed or dissolved, and then the inorganic fiber is charged and dispersed in water to form a slurry. Inorganic particles such as titanium oxide are added.

The first step in the second embodiment of the present invention can be performed in the same manner as in the first embodiment of the present invention.
Next, the inorganic particles are added to the slurry in which the cationic polymer and the inorganic fibers are charged, and stirred.

Although it does not specifically limit as an inorganic particle, For example, at least 1 sort (s) among the group which consists of bentonite, a titanium oxide, a silica powder, and an alumina powder is mentioned.

Bentonite is a colloidal clay mainly composed of montmorillonite, and has a characteristic of swelling when it contains water. For this reason, bentonite is added to the slurry containing the cationic polymer and the inorganic fibers, so that the dispersion state is almost the same as that of the water-soluble inorganic binder, and the fine particles dispersed in the slurry aggregate and adhere to the inorganic fibers. When bentonite is contained in the obtained heat insulating material, it plays a role as an adhesive that bonds together the inorganic fibers together with the fine particles constituting the water-soluble inorganic bander. Therefore, the mechanical strength of the heat insulating material containing bentonite is improved.

Titanium oxide has a function to scatter heat radiation, so if included in the heat insulating material, radiant heat is scattered and heat insulation performance is improved.
When the silica powder is contained in the heat insulating material together with the water-soluble inorganic binder, bubbles in the heat insulating material are reduced. Therefore, the heat insulating material is divided into a large number of bubbles, and heat conduction is inhibited, so that the heat insulating performance of the heat insulating material is improved.
Since alumina is excellent in heat resistance, the heat insulating material containing alumina powder has improved heat resistance.

The amount of bentonite added to 100 parts by weight of inorganic fibers is preferably 2 to 40 parts by weight, and more preferably 5 to 20 parts by weight.
When the added amount of bentonite with respect to 100 parts by weight of the inorganic fiber is within the above range, the bentonite functions appropriately as an adhesive and bonds the inorganic fibers with at least a part thereof. Accordingly, a heat insulating material having high strength can be obtained. When the content of bentonite is less than 2 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of bentonite that functions as an adhesive is small, so the strength of the heat insulating material is not improved. On the other hand, when the content of bentonite exceeds 40 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of bentonite in the slurry is large, so that the agglomeration does not sufficiently occur and the drainage when the slurry is dehydrated decreases. , Productivity decreases.

The amount of titanium oxide added to 100 parts by weight of inorganic fibers is preferably 10 to 70 parts by weight.
Since the addition amount of titanium oxide with respect to 100 parts by weight of the inorganic fibers is in the above range, heat radiation can be scattered, and further high heat insulation can be imparted to the heat insulating material. When the content of titanium oxide is less than 10 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of titanium oxide that scatters heat radiation is small, so that the heat insulation is not improved. On the other hand, when the content of titanium oxide exceeds 70 parts by weight with respect to 100 parts by weight of the inorganic fiber, the amount of fine particles serving as an adhesive becomes too large, and the amount of titanium oxide in the slurry is large. And the drainage of the slurry is reduced and the productivity is lowered.

The stirring time after adding the inorganic particles and adding the water-soluble inorganic binder in the second step is preferably 30 seconds to 5 minutes. When the stirring time is less than 30 seconds, the inorganic particles are not uniformly dispersed in water, and good aggregation cannot be performed. On the other hand, even if the stirring time exceeds 5 minutes, the uniform dispersion effect of the inorganic particles by stirring does not increase, which is not economical.
The inorganic particles added in the inorganic particle addition process do not greatly affect the cohesiveness of the slurry, and once added, they are dispersed in the liquid, but the negative charge of the inorganic fibers is neutralized by the cationic polymer. Therefore, it aggregates with the fine particles constituting the water-soluble inorganic binder and adheres to the inorganic fibers.

After passing through the inorganic particle addition step, the second step to the fourth step are performed. The second step to the fourth step in the second embodiment of the present invention can be performed in the same manner as in the first embodiment of the present invention. .

Hereafter, it enumerates about the effect of the manufacturing method of the heat insulating material of 2nd embodiment of this invention.
In the manufacturing method of the heat insulating material according to the present embodiment, the effects of (1) to (3) described in the first embodiment are exhibited, similarly to the manufacturing method of the heat insulating material according to the first embodiment of the present invention. The following effect (4) is achieved.
(4) In the method for manufacturing a heat insulating material of the present embodiment, at least one selected from the group consisting of bentonite, titanium oxide, silica powder, and alumina powder is added as inorganic particles, and the heat insulating material from which these are obtained Therefore, the characteristic according to the function of each inorganic particle can be provided to a heat insulating material.

Example 4
First, 10 parts by weight of cationized starch (Mermaid 350 made by Shikishima Starch) was added to 990 parts by weight of water, and stirred well for about 60 minutes to prepare diluted water in which the cationized starch was diluted to 1% by weight. .

Next, after adding 9000 parts by weight of water to the tank, adding the dilution water prepared in the above step and stirring, rock wool (Pacific Mineral Fiber, Pacific Mineral Fiber, SiO ₂ : 42.3 wt%, CaO : 35.5 wt%, Al ₂ O ₃ : 15.5 wt%, MgO 6.4 wt%, Fe ₂ O ₃ : 0.6 wt%, average fiber diameter: 5.0 μm) 100 parts by weight were added, Stir well for 1 minute.

Next, 10 parts by weight of titanium oxide (Rutile Flower S manufactured by Kinseimatic Co., Ltd.) was added and stirred well for 1 minute.

Next, 16.7 parts by weight (5.0 parts by weight in terms of solid content) of silica sol (Snowtex 30 manufactured by Nissan Chemical Industries, Ltd. (SiO ₂ concentration: 30% by weight)) was added and stirred again for 1 minute. .

Next, 20 parts by weight (2.0 parts by weight in terms of solid content) of a cationic flocculant (Polystron 705 manufactured by Arakawa Chemical Industries) was added and stirred for 1 minute, and then an anionic flocculant (Meisei Chemical Industry Co., Ltd.). 3 parts by weight (manufactured Phyrex M) (0.3 parts by weight in terms of solid content) was added, stirred for 1 minute, and then allowed to stand for 10 minutes to produce an aggregate.
Subsequently, a slurry containing the formed aggregates was poured into a mold for dehydration, and dehydrated molding was performed to produce a molded heat insulating body containing moisture.
Then, after drying the shaping | molding heat insulating body containing a water | moisture content at 105 degreeC, it cut and manufactured the heat insulating material. Table 3 shows the weight (parts by weight) of added substances such as added cationized starch.

Moreover, the supernatant liquid of the slurry at the time of producing the aggregate was collected as in Example 1, and the transparency of the supernatant liquid was measured to evaluate the aggregability of the slurry. Table 4 shows the measurement results of the absorbance of the supernatant.

Further, in the same manner as in Example 1, the aggregation property was evaluated by a dehydration test of the aggregate. Table 4 shows the measurement evaluation results of the dehydration time.

(Examples 5 and 6)
Cationic starch, titanium oxide, silica sol, cationic, except that the amounts of cationized starch, titanium oxide, biosoluble fiber, silica sol, cationic flocculant and anionic flocculant were changed. A heat insulating material was produced by adding a flocculant and an anionic flocculant to agglomerate the inorganic fibers charged in water, followed by dehydration molding. Table 3 shows the weight (parts by weight) of added substances such as added cationized starch. In Examples 4 to 6, the addition amount of the acid value titanium is changed in the range of 10 to 70 parts by weight.

Further, as in Example 1, the cohesiveness of the slurry was evaluated by determining the absorbance of the supernatant of the slurry. Table 4 shows the measurement results of the absorbance of the supernatant of the slurry.

Further, in the same manner as in Example 1, the aggregation property was evaluated by a dehydration test of the aggregate. Table 4 shows the measurement results of the dehydration time. Furthermore, the density and bending strength of the heat insulating material obtained in Example 5 were measured in the same manner as in Example 1. The results are shown in Table 4.

(Comparative Examples 2 to 4)
The addition amount of cationized starch, cationic flocculant or anionic flocculant was changed to the weight shown in Table 3 (in Comparative Example 2, no cationized starch was added, in Comparative Example 3, no cationic flocculant was added, In Comparative Example 4, the anionic flocculant was not added), except that the inorganic fibers charged into water were used in the same manner as in Example 4 using cationized starch, silica sol, cationic flocculant and anionic flocculant. A heat insulating material was produced by agglomeration and dehydration molding. Table 3 shows the weight (parts by weight) of added substances such as added cationized starch.

Further, as in Example 1, the cohesiveness of the slurry was evaluated by determining the absorbance of the supernatant of the slurry. Table 4 shows the measurement results of the absorbance of the supernatant of the slurry.

Further, in the same manner as in Example 1, the aggregation property was evaluated by a dehydration test of the aggregate. Table 4 shows the measurement results of the dehydration time. Further, the density and bending strength of the heat insulating material obtained in Comparative Example 2 were measured in the same manner as in Example 1. The results are shown in Table 4.

As apparent from Tables 3 and 4, in the case of Examples 4 to 6, since cationized starch was added first, rock wool was used as inorganic fibers, and titanium oxide was added as inorganic particles. Even in this case, the absorbances of the supernatants of Examples 4 to 6 were 0.107, 0.122, and 0.154 compared to the absorbance of the supernatant of Comparative Example 2 to which no cationized starch was added. The supernatant liquid is transparent. Therefore, in Examples 4 to 6, it can be said that the aggregates are well aggregated.
Accordingly, the dehydration time of Examples 4 to 6 is as short as 30 seconds, 27 seconds, and 29 seconds, respectively, compared to 40 seconds of Comparative Example 2, and it can be seen that the dehydration work can be performed efficiently. Moreover, the density of Example 5 is 0.38 g / cm ³ , which is higher than the density of 0.32 g / cm ³ of Comparative Example 2, and the bending strength of Example 5 is 1.98 MPa, which is that of Comparative Example 2. It is higher than 0.14 MPa. Therefore, in Examples 4 to 6, it is considered that the density of the obtained heat insulating material is higher and the strength is higher than in the case of Comparative Example 2.

On the other hand, in the case of Comparative Examples 3 and 4, since the cationized starch was not added, the cationic flocculant was not added, or the anionic flocculant was not added, the absorbance of the supernatant was 0 respectively. .323 and 0.277, which are higher than those of Examples 4 to 6, indicating that the aggregation state of the inorganic fibers is not good. Accordingly, the dehydration times of Comparative Examples 3 and 4 are as long as 46 seconds and 39 seconds, respectively, indicating that the dewatering operation cannot be performed efficiently. Therefore, in the case of Comparative Examples 3 and 4, it can be seen that the density of the obtained heat insulating material is low and the strength is also low.

(Examples 7 to 9 and Comparative Example 5)
In Examples 7 to 9 and Comparative Example 5, bentonite (Aid Plus manufactured by Mizusawa Chemical Industry Co., Ltd.) was used as inorganic particles instead of titanium oxide.
A cationized starch, bentonite, silica sol, a cationic flocculant and an anionic flocculant were added in the same manner as in Example 4 except that the weight of the additive substance such as cationized starch containing bentonite was changed, and the mixture was put into water. A heat insulating material was manufactured by agglomerating inorganic fibers and performing dehydration molding. Table 5 shows the weight (parts by weight) of added substances such as added cationized starch. In Examples 7 to 9, the amount of bentonite added was changed in the range of 2 to 40 parts by weight. In Comparative Example 5, cationized starch was not added.

Further, as in Example 1, the cohesiveness of the slurry was evaluated by determining the absorbance of the supernatant of the slurry. Table 6 shows the measurement results of the absorbance of the supernatant of the slurry.

In the same manner as in Example 1, the aggregation property was evaluated by a dehydration test of the aggregate. The measurement results of the dehydration time are shown in Table 6.

As is clear from Tables 5 and 6, in Examples 7 to 9, since cationized starch was added first, biosoluble fiber was used as the inorganic fiber, and bentonite was used as the inorganic particle. In this case, the absorbances of the supernatants of Examples 7 to 9 were 0.127 and 0.101 as compared with Comparative Example 5 (absorbance 0.222 of the supernatant) to which no cationized starch was added. , 0.063, and the supernatant liquid is transparent. Since the supernatant liquid is transparent, it can be seen that Examples 7 to 9 are well aggregated.
Accordingly, the dehydration time is shorter than that of Comparative Example 5 of 2 minutes and 11 seconds, and Examples 7 to 9 are as short as 1 minute 32 seconds, 40 seconds, and 18 seconds, respectively, and can perform dewatering work efficiently. Recognize.

(Examples 10 to 12 and Comparative Example 6)
In Examples 10 to 12 and Comparative Example 6, titanium oxide was used as the inorganic particles, and biosoluble fibers similar to those used in Example 1 were used as the inorganic fibers.
A cationized starch, titanium oxide, silica sol, a cationic flocculant and an anionic flocculant were added in the same manner as in Example 4 except that the weight of the additive substance including titanium oxide and rock wool was changed, and the mixture was put into water. The heat-insulating material was manufactured by agglomerating the inorganic fibers thus obtained and performing dehydration molding. Table 7 shows the weight (parts by weight) of added substances such as added cationized starch. In addition, in Examples 10-12, the addition amount of acid value titanium was changed in the range of 10 weight part-70 weight part, and in the comparative example 6, cationized starch is not added.

Further, as in Example 1, the cohesiveness of the slurry was evaluated by determining the absorbance of the supernatant of the slurry. Table 8 shows the measurement results of the absorbance of the supernatant of the slurry.

In the same manner as in Example 1, the aggregation property was evaluated by a dehydration test of the aggregate. Table 8 shows the measurement results of the dehydration time.

As is clear from Tables 7 and 8, in the case of Examples 10 to 12, since cationized starch was added first, a biosoluble fiber was used as the inorganic fiber, and the acid value titanium was used as the inorganic particle. In the case where the lysate was used, the absorbance of the supernatants of Examples 10 to 12 was 0.098, 0 as compared with Comparative Example 6 (absorbance of the supernatant 1.011) in which no cationized starch was added. .129 and 0.146, and the supernatant is transparent. Since the supernatant liquid is transparent, it can be seen that Examples 10 to 12 are well aggregated.
Accordingly, the dehydration time of Examples 10 to 12 is as short as 25 seconds, 22 seconds, and 27 seconds, respectively, compared with 45 seconds of Comparative Example 6, and it can be seen that the dehydration work can be performed efficiently. .
As described above, as apparent from Tables 1 to 8, by the method for producing a heat insulating material of the present invention, a mixture containing inorganic fibers (and inorganic particles) can be quickly aggregated in a short time. It can be seen that the heat insulating material can be produced with high productivity by putting it into a mold and performing dehydration molding. In particular, it can be seen that when a biosoluble fiber or rock wool is used as the inorganic fiber, the heat insulating material can be manufactured extremely efficiently. In addition, it is thought that the same result is acquired even if it uses an alumina fiber, a silica-alumina fiber, or a silica alumina zirconia fiber as an inorganic fiber.

(Other embodiments)
In the first embodiment of the present invention and the second embodiment of the present invention, the cationic polymer is charged into water, dispersed or dissolved, and then the inorganic fiber is charged. The charging order of the cationic polymer and the inorganic fiber is as follows. There is no particular limitation, and the cationic polymer may be charged after the inorganic fiber is charged first.

Moreover, in the manufacturing method of the heat insulating material of this invention, in order to improve the moldability at the time of shaping | molding by suction filtration, you may add an organic binder to a slurry. The organic binder is not particularly limited. For example, acrylic resins, rubbers such as acrylic rubber, water-soluble organic polymers such as carboxymethyl cellulose and polyvinyl alcohol, thermoplastic resins such as styrene resins, and thermosetting resins such as epoxy resins. Etc. Among these, acrylic rubber, acrylonitrile-butadiene rubber, and styrene-butadiene rubber are preferable.

As described above, the heat insulating material manufactured by the method for manufacturing a heat insulating material of the present invention has sufficient density and strength, and maintains sufficient strength even when used at high temperatures. It can use suitably for uses, such as a heater.

Claims (10)

A cationic polymer and an inorganic fiber are put into water, and after making the slurry in which the inorganic fiber and the cationic polymer are dispersed in water, a water-soluble inorganic binder is added to the slurry, and then the water-soluble inorganic binder is added. A method for producing a heat insulating material in which a cationic flocculant is added to an added slurry, an anionic flocculant is further added to produce an agglomerate, and then the obtained agglomerate is put into a mold and subjected to dehydration molding. And
In the step of introducing the cationic polymer and the inorganic fiber into water, the cationic polymer is first introduced into water, and the cationic polymer is dispersed and / or dissolved in water, and then the inorganic fiber is immersed in water. A method for producing a heat insulating material, characterized by being charged and dispersed . The method for producing a heat insulating material according to claim 1 , wherein the cationic polymer is cationized starch. The method for producing a heat insulating material according to claim 1 or 2 , wherein the inorganic fiber is a biosoluble fiber, rock wool, alumina fiber, silica-alumina fiber, or silica alumina zirconia fiber. The method for manufacturing a heat insulating material according to claim 3 , wherein the inorganic fiber is a biosoluble fiber or rock wool. The method for manufacturing a heat insulating material according to claim 3 or 4 , wherein the biosoluble fiber includes an alkali metal compound or an alkaline earth metal compound. The method for producing a heat insulating material according to any one of claims 1 to 5 , wherein the inorganic particles are added before the water-soluble inorganic binder is added, after the cationic polymer and the inorganic fibers are put into water. The method for manufacturing a heat insulating material according to claim 6 , wherein the inorganic particles are at least one selected from the group consisting of bentonite, titanium oxide, silica powder, and alumina powder. The method for manufacturing a heat insulating material according to claim 7 , wherein the amount of bentonite added to 100 parts by weight of the inorganic fiber is 2 to 40 parts by weight. The method for producing a heat insulating material according to claim 7 , wherein the amount of titanium oxide added is 10 to 70 parts by weight with respect to 100 parts by weight of the inorganic fibers. The method for producing a heat insulating material according to any one of claims 1 to 9 , wherein an addition amount of the water-soluble inorganic binder converted to a solid content with respect to 100 parts by weight of the inorganic fiber is 0.1 to 20 parts by weight.

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