JP2514036B2 - Method for producing colored potassium titanate fiber - Google Patents

Description

The present invention relates to a method for producing colored potassium titanate fibers.

[Conventional technology]

Potassium hexatitanate fiber [K ₂ O ・ 6TiO ₂ ] and potassium tetratitanate fiber [K ₂ O ・ 4TiO ₂ ] have excellent heat resistance and wear resistance. Further, it is a synthetic inorganic fiber having a reinforcing property suitable as a reinforcing fiber such as plastic or metal. The melting method, which is known as a typical manufacturing method, is a method of heating titanium dioxide (Ti
O ₂ ) titanium compound (high-purity purified titanium oxide, natural rutile sand, etc.) and potassium oxide (K ₂ O) by heating
The starting material is a mixture with a potassium compound (potassium carbonate, etc.) to be heated, the raw material mixture is heated and melted, and then the molten product is converted into a fibrous solidified product, and then the chemical composition of the target fiber composition. Is a method for obtaining the target potassium titanate fiber through steps such as a potassium removal treatment for converting into a desired structure and a heat treatment (calcination) for converting the crystal structure into a target fiber crystal structure (Japanese Patent Publication No. 54
-019239, JP-A-58-158688). Further, recently, various improvement methods for the purpose of improving the fiber morphology of potassium titanate fibers and improving the fiber yield, for example, by rapidly cooling the raw material heating and melting product to form an amorphous solidified product, Then, a method of obtaining potassium titanate fiber having a desired composition and structure through a potassium removal treatment or a heat treatment step has been proposed (Japanese Patent Application Nos. 61-102875, 61-206218 and 61-2062).
No. 19, etc.).

[Problems to be solved by the invention]

The potassium titanate fiber is a white fiber having a high refractive index and a strong hiding property. (Fibers obtained using natural rutile sand as the titanium compound have a pale yellow tint). Therefore, the molded product obtained by mixing the fiber, for example, in plastic or the like, or binding with a suitable binder, or papermaking has a strong whiteness, and a colorant such as a dye or a pigment is tentatively used. Even if added, the color tone is weakened, and the desired color tone cannot be given to the molded product. As a countermeasure against this, there has been proposed one in which various color tones are imparted by coating the surface of potassium titanate fiber with a coloring agent such as a pigment or a dye and a binder (JP-A-58-199767). issue). However, this requires complicated steps such as preparation of a treatment liquid containing a colorant and a binder, treatment of fibers with the treatment liquid, and heat treatment for consolidating the colorant on the fiber surface.

In view of the above, the present invention aims to provide a method for producing potassium titanate fibers having various color tones without adding a special treatment step.

[Means and Actions for Solving Problems]

According to the present invention, in a method for producing potassium titanate fibers by a melting method, 0.1 to 5% by weight of one or two or more coloring elements is added to a mixture of a titanium compound and a potassium compound, which are starting materials thereof. It has a feature.

Coloring elements used in the present invention, for example, Co, Fe, Cu,
V, Ni, Mn, etc. The coloring element mixed in the raw material is incorporated into the crystal structure of the obtained fiber, and as a result, the absorption band in the visible light region (400 to 800 Nm) of the fiber changes. The complementary color of the absorption band appears as the color of the fiber.
That is, the color of the fiber obtained by the present invention is not the colorant applied to the surface of the fiber, but the color of the fiber itself caused by the change in the absorption band of the fiber.

The coloring element is selected according to the color tone of the target fiber. For example, by adding Co or Cu, green fiber, V or Ni
Addition of yellow fiber, addition of Fe brown fiber,
Further, by adding Mn, a gray fiber is obtained, and when a plurality of kinds of coloring elements are used in combination, a fiber having an intermediate color between them is obtained.

The coloring element may be either a simple substance or an oxide. The blending amount in the raw material mixture is 0.1-5%
(Weight) When compounded in the form of an oxide, it is 0.1 to 5% in terms of the weight of the element alone. The lower limit of 0.1% is that if it is less than that, the coloring effect is insufficient, while the upper limit of 5% is that a sufficient coloring effect is obtained by adding up to 5%. If the amount exceeds the above range, the effect is almost saturated, and the yield and quality of the fiber may deteriorate due to excessive addition.

When two or more coloring elements are used in combination, the total amount of each element may be 5% unless the addition amount of each element is 5%.

In the fiber manufacturing method of the present invention, there is no particular limitation except that a predetermined amount of the coloring element is mixed in the starting material as described above, heating and melting the raw material, cooling and solidifying the molten product,
Each process such as potassium removal treatment and calcination may be performed under known general conditions.

The titanium compound in the raw material preparation is high-purity purified titanium oxide, natural rutile sand, natural anatase sand, titanium slag, etc., while potassium carbonate (K ₂ CO ₃ ) is most commonly and preferably used as the potassium compound. In addition, hydroxides, nitrates, halides and the like may be used.
The titanium compound and the potassium compound are mixed so that the molar ratio of TiO ₂ / K ₂ O is about 2 (1.5 to 2.5), but it is also possible to adjust the molar ratio to a high value of 3 to 6. is there. A predetermined amount of a coloring element is mixed with the mixture of the titanium compound and the potassium compound to form a starting material, which is heated and melted to obtain a molten product.

When the starting material is one in which the molar ratio of TiO ₂ / K ₂ O is adjusted to about 2, the heated and melted product is injected into, for example, a cooling mold, and directionally solidified in one direction, Potassium dititanate fiber (K ₂ O ・ 2TiO ₂ ) as primary phase fiber
Are produced, and a fibrous solidified product which is an aggregate of the fibers is obtained. This is immersed in water or an aqueous acid solution, and if necessary, agitation such as propeller agitation is performed to perform potassium removal treatment to elute K ⁺ 5 ions, and the molar ratio of TiO ₂ / K ₂ O is increased to about 5. After that, the mixed fiber of potassium tetratitanate and potassium hexatitanate (K ₂ O.4TiO ₂ , K ₂ O.6TiO ₂ ) is obtained by recovering from the liquid, dehydrating and drying, and then calcining. When the coloring element compounded in the starting material is, for example, Co, the fiber is green. If desired,
After being subjected to potassium removal treatment again, K ⁺ ions were eluted until the molar ratio of TiO ₂ / K ₂ O became about 6, then dehydrated and dried,
A green potassium hexatitanate fiber is obtained through the firing step.

In addition, heating and melting product (molar ratio of TiO ₂ / K ₂ O: about 2)
Was rapidly cooled by a metal twin roll method to obtain an amorphous solidified product, and then titanium dioxide was added thereto to form a mixture having a TiO ₂ / K ₂ O molar ratio of about 4, and the mixture was pulverized and homogenized. By firing, potassium tetratitanate fiber is obtained. When the coloring element incorporated in the starting material is Ni, the fiber exhibits a bright yellow color. By subjecting this fiber to potassium removal treatment to bring the molar ratio of TiO ₂ / K ₂ O to about 6, and then subjecting it to firing treatment, yellow potassium hexatitanate fiber is obtained.

Further, a molten product obtained by heating and melting a starting material prepared so that the molar ratio of TiO ₂ / K ₂ O is about 4 is rapidly cooled with a metal twin roll to form an amorphous solidified product. By firing this, potassium tetratitanate fiber is obtained. When the coloring element is Fe, the fiber has a brown color. By subjecting this to potassium removal treatment to bring the molar ratio of TiO ₂ / K ₂ O to about 6 and then adding a step of firing, brown potassium hexatitanate fibers can be obtained.

The above-mentioned manufacturing process is an example, and there is no obstacle to adding various modifications to the series of processes for the purpose of improving fiber yield, improving fiber morphology, and the like.

〔Example〕

Example 1 (1) High-purity purified titanium oxide (purity 99%) and industrial potassium carbonate (purity 99%) were mixed so that the molar ratio of TiO ₂ / K ₂ O was 2, and this was mixed with a coloring element. As a starting material, 0.5% of Co is mixed in the form of oxide (Co ₃ O ₄ ).

(2) After the above starting material is heated and melted at 1100 ° C., it is poured into a mold to obtain a solid substance composed of primary phase potassium dititanate fiber.

(3) The fibrous solidified product is immersed in 50 times the normal temperature water,
K ⁺ ions are eluted under a propeller stirring for 24 hours until the molar ratio of TiO ₂ / K ₂ O becomes about 4. It is recovered from water, dehydrated and dried, and calcined at 1000 ° C to obtain fibers. X
Line diffraction shows that the resulting fiber is a mixed fiber of potassium tetratitanate and potassium hexatitanate. The fibers have a bright green color. Fiber length: 10-30 μm, Fiber diameter: 0.5-
2.0 μm.

(4) 10 times the amount of sulfuric acid aqueous solution (0.5
%) And elute K ⁺ ions for 1 hour under stirring with a propeller to make the molar ratio of TiO ₂ / K ₂ O about 6 and recover from water, and after dehydration and drying By firing at 800 ° C., green potassium hexatitanate fibers were obtained.

Example 2 (1) Natural rutile sand (purity 95%) and industrial potassium carbonate (purity 99%) were mixed so that the molar ratio of TiO ₂ / K ₂ O was 2, and this was mixed as a coloring element. 5% metal Ni powder
It is mixed and used as a starting material.

(2) The above starting material is heated and melted at 1100 ° C., and then the molten product is rapidly cooled by a metal twin roll rotating at high speed to obtain an amorphous solidified product. Titanium dioxide powder was added to this amorphous solidified product to form a mixture having a TiO ₂ / K ₂ O molar ratio of 4.
After homogenization by pulverization, a potassium tetratitanate fiber was obtained through a step of firing at 1000 ° C. (X-ray diffraction). The fiber obtained has a bright yellow color. Fiber length: 1 to 20 μm, fiber diameter: 0.2 to 1.
0 μm.

(3) Immerse the yellow potassium tetratitanate fiber in 10 times the amount of room temperature water and elute K ⁺ ions under stirring with a propeller
A TiO ₂ / K ₂ O molar ratio was set to 6, dehydration / drying, and baking at 800 ° C. gave green potassium hexatitanate fibers (X-ray diffraction). The fiber form is the same as the above-mentioned potassium tetratitanate fiber.

Example 3 (1) Natural rutile sand (purity 95%) and industrial potassium carbonate (purity 99%) were mixed so that the molar ratio of TiO ₂ / K ₂ O was 4, and this was mixed as a coloring element. 5% Fe is compounded in the form of oxide (Fe ₂ O ₃ ) to make a starting material.

(2) The above starting material is heated and melted at 1380 ° C., and then rapidly cooled by a metal twin roll rotating at high speed to obtain an amorphous solidified product. The amorphous solidified product is fired at 1000 ° C. to obtain potassium tetratitanate fiber (X-ray diffraction). The obtained fiber has a brown color. Fiber length: 1 to 20 μm, fiber diameter: 0.2 to 1.0 μm.

(3) The brown potassium tetratitanate fiber is immersed in 10 times the amount of room temperature water, and K ⁺ ions are eluted under stirring with a propeller.
A TiO ₂ / K ₂ O molar ratio was set to 6, dehydration / drying, and baking at 800 ° C. gave brown potassium hexatitanate fibers (X-ray diffraction). The fiber morphology is the same as potassium fiber in the above-mentioned tetratitanic acid.

〔The invention's effect〕

According to the method of the present invention, potassium titanate fibers having various color tones can be obtained. The coloring of the fiber is only required to add a trace amount of a coloring element to the starting material and does not require a complicated treatment step such as the case where a coloring agent such as a dye is applied to the surface of the fiber, which is extremely efficient and economical. It is possible to produce colored fibers. When the fiber is coated with a coloring agent such as a dye, discoloration or fading may occur due to external conditions (heat influence in use environment, chemical dissolution loss, etc.). Since the color tone of the obtained fiber is the color tone of the fiber itself, there is no such problem and the stability of the color tone is excellent. Moreover, the color tone can be freely selected according to the type and combination of coloring elements.

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Claims (2)

(57) [Claims] 1. A method for producing a potassium titanate fiber by a melting method using a mixture of a titanium compound which becomes titanium dioxide by heating and a potassium compound which becomes potassium oxide by heating as a starting material. To a mixture of one or more coloring elements alone or their oxides.
A method for producing a colored potassium titanate fiber, which comprises blending 0.1 to 5% by weight (in the case of an oxide, a single conversion value). 2. The coloring element is Co, Fe, Cu, V, Ni, or
The method for producing a colored potassium titanate fiber according to the above item 1, which is Mn.