JP2006348188A - Porous functional filler and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous functional filler obtained by sterically combining laminar materials, which materials are hydrophobic and have uniform pore size, and to provide a method for simply and well reproducibly producing the porous functional filler. <P>SOLUTION: The porous functional filler is a composite material obtained by inserting an inorganic material between the layers of a laminar (layered) material, wherein the composite material has a sterically combined structure. The method for producing the porous functional filler comprises preparing an interlayer-crosslinked product of a laminar clay mineral with an inorganic material by reacting the laminar clay mineral or a laminar clay mineral powder, dispersed in a solvent, with a colloidal solution of an inorganic precursor at room temperature or under heating and making the thin-layered platy particles a three-dimensional body to produce the composite material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure in which a layered substance having a hydrophobic and uniform pore size is sterically bonded, and the structure can be advantageously used for a functional product such as a friction material that requires high strength and hydrophobicity. The present invention relates to a method for producing easily and reproducibly.

  For the purpose of preventing noise generated during braking, various techniques have been developed that utilize a layered substance having high water absorption, zeolite, or the like as a friction / wear adjusting component to be blended with the friction material. For example, Patent Document 1 discloses an inorganic powder having a planar crystal structure such as fiber and mica and talc as a friction material that can effectively prevent noise during braking while preventing a decrease in braking force as much as possible. A friction material made of a thermosetting resin containing granules and a method for manufacturing the friction material are disclosed.

  Patent Document 2 was coated with a resin component as a fiber component, a thermosetting resin component, and a filler powder component as a friction material having good squeal performance during braking and good fade resistance and wear resistance. A friction material comprising vermiculite is disclosed. Further, Patent Document 3 discloses a non-asbestos brake for automobiles that contains zeolite having high water absorption as a fiber base material, a binding material, and a friction modifier as an automobile brake pad that prevents the generation of noise called creep creep (goo sound). A pad is disclosed.

Japanese Patent No. 2867661 Japanese Patent No. 2827140 JP 2000-38571 A

Conventionally, since a layered substance generally has high water absorption between layers, when used as a filler of a product, deformation and cracking occur due to expansion during water absorption. In addition, when a composite material using a layered substance as a filler is compression-molded, plate-like particles having a high aspect ratio are oriented perpendicular to the molding pressure direction, so the strength in the direction perpendicular to the molding pressure direction decreases. . Therefore, from the two points of water absorption and strength reduction, a general layered substance has a problem in being used as a filler for functional products.
Further, porous materials such as zeolite also have a problem that due to their high water absorption, quality deteriorates when used as a friction material and other fillers, and sufficient humidity control is required for storage security.

  The present invention has been made in view of such a conventional problem, and is a structure in which a layered substance having a hydrophobic and uniform pore size is sterically bonded, and the structure is easily and reproducibly. The object is to provide a method for manufacturing.

  The porous functional filler of the present invention is oriented perpendicularly to the water absorption between layers and the molding pressure direction at the time of compression molding by sterically bonding a layered substance having a hydrophobic and uniform pore diameter. Since two of these are suppressed, the problems of water absorption and strength reduction are solved.

That is, the present invention has the following configuration in order to achieve the above object.
(1) A porous functional filler, which is a composite material in which an inorganic substance is inserted between layers of a layered substance and has a structure in which the composite material is sterically bonded.
(2) Layered clay mineral dispersed in a solvent or layered clay mineral powder and a colloidal solution of an inorganic precursor are reacted at room temperature or while heating to produce an interlayer cross-linked body of the layered clay mineral and the inorganic material. A method for producing a porous functional filler, characterized in that a composite material is produced by three-dimensionalizing thin plate-like particles.

(3) The layered clay mineral is one or more of natural clay minerals or artificial synthetic clays having a cation exchange capacity such as kaolinite, smectite, vermiculite, mica, brittle mica, chlorite and the like. (2) A method for producing the porous functional filler according to (2).
(4) The colloidal solution of the inorganic precursor is Si, Ti, Zr, Sn, Ge, Al, B, Fe, Ga, P, V, Y, As, Sc, Cr, Nb, Mo, Ca, Mg, One or more kinds of organic compounds or inorganic salts such as Pb, Sr, Zn, Cu, Ni, Co, Mn, Be, Ba, alkoxides of metal and metalloid, and one kind of inorganic or organic solvent for halides, Alternatively, the porous functional filler according to (2), wherein the porous functional filler is dissolved or dispersed in a mixed solvent of two or more of the solvents, or is hydrolyzed through aging after dissolution or dispersion Manufacturing method.
(5) The colloidal solution of the inorganic precursor is polyvinyl alcohol, polyvinyl butyral, vinyl acetate, vinyl chloride, methacryl, acrylic, styrene, polyethylene, polypropylene, polyamide, cellulose, The method for producing a porous functional filler according to (2), wherein an isobutylene-based or vinyl ether-based thermoplastic resin is dissolved or dispersed.

The present invention relates to a layered clay mineral and an inorganic substance by reacting a layered clay mineral or a layered clay mineral powder dispersed in a solvent such as water with a sol (colloid) solution of an inorganic precursor at room temperature or while heating. At the same time, a three-dimensional skeleton of thin plate-like particles is formed. When the heat treatment is further performed, the wet gelled material on the interlayer and the layer surface undergoes a dehydration condensation reaction depending on the heating conditions to become a mixture of inorganic hydroxide and inorganic oxide or an inorganic oxide, which adheres to the surface and interlayer of the clay mineral and expands. Therefore, the swelling due to water absorption is suppressed. On the other hand, it functions as an inorganic binder that firmly supports the three-dimensional skeleton. Finally, a structure in which layered substances having hydrophobic and uniform pore diameters are sterically bonded is obtained.
The matter described above is shown in FIG. 1 as an image diagram of the structure. In FIG. 1, 1 is a layered clay mineral and 2 is an inorganic substance.

  In the present invention, as the layered clay mineral, for example, natural clay minerals having artificial cation exchange ability such as kaolinite, smectite, vermiculite, mica, brittle mica, chlorite and artificial synthetic clay are used.

Sol (colloid) solutions of inorganic precursors are Si, Ti, Zr, Sn, Ge, Al, B, Fe, Ga, P, V, Y, As, Sc, Cr, Nb, Mo, Ca, Mg, Pb. , Sr, Zn, Cu, Ni, Co, Mn, Be, Ba, organic compounds or inorganic salts such as metal and metalloid alkoxides, halides, inorganic or organic solvents, or Those dissolved or dispersed in a mixed solvent of two or more solvents, or those dissolved or dispersed and then hydrolyzed through aging are used.
Furthermore, if necessary, polyvinyl alcohol, polyvinyl butyral, vinyl acetate, vinyl chloride, methacryl, acrylic, styrene, polyethylene, polypropylene, polyamide, cellulose, isobutylene, vinyl ether can be used in the solution. What melt | dissolved or disperse | distributed the thermoplastic resin is used.
The colloidal solution (sol) of these inorganic precursors is in the form of a ceramic precursor or metal oxide in the composite material having the structure shown in FIG.

  The solvent for dispersing the layered clay mineral is one kind of inorganic or organic solvent, or a mixed solvent of two or more kinds thereof, and any of acidic, neutral and alkaline solvents is used. A preferable solvent is ethanol from the viewpoints of safety in the working environment and low cost.

  Hereinafter, the present invention will be described in detail and specifically with reference to Examples, but the present invention is not limited to these Examples.

Example 1 and Comparative Examples 1-2
10 g of synthetic fluorine mica was added to 600 ml of distilled water and stirred well. Dilute 23 g of tetraethoxysilane with 200 ml of ethanol, add 20 g of acetic acid and 8 g of distilled water, concentrate at a temperature of 80 ° C. or lower until the volume reaches 125 ml, and then add it to the synthetic fluoric mica dispersion. After stirring for a period of time, ripening treatment was performed for 2 hours in a heating furnace at 200 ° C. The filler of this invention was obtained through water washing, filtration, drying, and a grinding | pulverization process. In the above operation, when acetic acid and distilled water are added to an ethanol solution of tetraethoxysilane, tetraethoxysilane is hydrolyzed to form a silica sol, which is concentrated to obtain a concentrated silica sol solution.

  A test piece to which 25% by volume of phenol resin, 55% by volume of calcium carbonate and 20% by volume of the filler of the present invention were added was prepared by compression molding, and a water absorption test, a strength test, and a porosity measurement were performed. As Comparative Example 1, a synthetic fluorine mica was prepared, and as Comparative Example 2, a test piece to which calcium carbonate was added was prepared, and the same test was performed.

(Water absorption test)
When the water absorption was confirmed by leaving it in an atmosphere of temperature 50 ° C. and humidity 95% for 72 hours, the test piece using the synthetic fluorine mica (Comparative Example 1) was expanded and cracked, but the filler of the present invention was added. The test piece did not expand as much as the calcium carbonate (Comparative Example 2) was added, and no cracks were observed.

(Strength test)
In the strength test when sheared in the direction perpendicular to the molding pressure, the strength of the test piece to which the filler of the present invention was added was the highest, approximately twice that of the test piece to which synthetic fluorine mica (Comparative Example 1) was added, and calcium carbonate ( The strength was about 1.5 times that of the test piece to which Comparative Example 2) was added. Moreover, the strength of the test piece to which the filler of the present invention was added when the bending test was performed in the same direction as the molding pressure was about twice that of the test piece to which calcium carbonate (Comparative Example 2) was added. The test piece to which Example 1) was added showed the same strength. The results of these experiments are shown in Table 1.

(Measurement of porosity)
The test piece to which the filler of the present invention is added has pores at a level of several tens of nanometers about twice that of the test piece to which synthetic fluorine mica (Comparative Example 1) is added, and the test piece to which calcium carbonate (Comparative Example 2) is added. The pores at the level of several tens of nm were close to zero.

  Since the porous functional filler of the present invention is a composite material having a structure in which an inorganic substance is inserted between layers of a layered substance and is three-dimensionally bonded, it is a three-dimensionally bonded structure having a hydrophobic and uniform pore size. The disadvantages of the conventional layered materials that exhibit the characteristics of the layered material and are oriented perpendicularly to the direction of water absorption between layers and compression molding are suppressed and eliminated. It is a useful filler (filler) having wide applicability as an industrial machine brake friction material, structural adhesive, structural member, and molding material.

It is an image figure which shows the structure of the porous functional filler of this invention.

Explanation of symbols

1 Layered clay mineral 2 Inorganic matter

Claims (5)

  A porous functional filler, which is a composite material in which an inorganic substance is inserted between layers of a layered substance and has a structure in which the composite material is sterically bonded.   A lamellar clay mineral dispersed in a solvent, or a layered clay mineral powder and a colloidal solution of an inorganic precursor are reacted at room temperature or while heating to produce a layered clay mineral-inorganic inorganic cross-linked product. A method for producing a porous functional filler, comprising producing a composite material by three-dimensionalizing layered plate-like particles.   3. The layered clay mineral is one or more kinds of natural clay minerals or artificial synthetic clays having a cation exchange ability such as kaolinite, smectite, vermiculite, mica, brittle mica, chlorite and the like. A method for producing a porous functional filler.   The inorganic precursor colloidal solution is Si, Ti, Zr, Sn, Ge, Al, B, Fe, Ga, P, V, Y, As, Sc, Cr, Nb, Mo, Ca, Mg, Pb, Sr. , Zn, Cu, Ni, Co, Mn, Be, Ba, organic compounds or inorganic salts such as alkoxides of one or more metals and metalloids, halides as one kind of inorganic or organic solvents, or 2 The method for producing a porous functional filler according to claim 2, wherein the porous functional filler is dissolved or dispersed in a mixed solvent of two or more kinds of solvents or hydrolyzed through aging after dissolution or dispersion.   The colloidal solution of the inorganic precursor is polyvinyl alcohol, polyvinyl butyral, vinyl acetate, vinyl chloride, methacryl, acrylic, styrene, polyethylene, polypropylene, polyamide, cellulose, isobutylene, 3. The method for producing a porous functional filler according to claim 2, wherein a vinyl ether-based thermoplastic resin is dissolved or dispersed.

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