JPH08133596A - Fiber guide and its manufacture - Google Patents

Abstract

PURPOSE: To provide a fiber guide excellent in wear resistance which never deteriorate the quality of yarn by forming the sliding surface with at least a fiber of the fiber guide from a ceramic having specified main component and average crystal grain size, and making no void prevent on the sliding surface. CONSTITUTION: The sliding surface with at least a fiber 2 of a fiber guide 1 is formed of a ceramic containing 99.9wt.% or more of Al2 O3 as a main component and having an average crystal grain size of Al2 O3 less than 2μm, and specified so that no void exceeding 30μm is present on the sliding surface. Such a fiber guide 1 is manufactured by a process of molding an alumina starting powder having an Al2 O3 purity of 99.9wt.% or more and an average grain size of 0.1-0.5μm into a prescribed form followed by baking at 1400-1700 deg.C. Namely, by using a highly pure and extremely fine Al2 O3 starting material, the void and grain boundary in the sintered compact are minimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber guide made of alumina ceramics and a method for manufacturing the fiber guide.

[0002]

Guides are used for guiding fibers in textile machines. As the material of this fiber guide, metal and glass are used for natural fibers, but when spinning, winding, and drawing synthetic fibers, they have excellent wear resistance without damaging the yarn. Materials are required.

As a concrete material for the conventional synthetic fiber guide, a metal or a metal plated with hard chrome, or ceramics such as alumina and titania having particularly high wear resistance is used.

However, in recent years, with the remarkable progress of the textile machine, the yarn speed of the processed yarn has been further increased, and the surface condition of the fiber guide becomes a problem as a yarn passage and a strong control element during use. There is. In other words, as the speed of the textile machine increases, deterioration of the yarn quality due to the surface condition of the fiber guide is taken up as a major problem. Therefore, there is a demand for a fiber guide that is not only highly wear-resistant, but also that does not damage the yarn and that does not deteriorate the yarn quality.

[0005]

In order to meet these required characteristics, a fiber guide made by plating a metal material with chrome does not deteriorate the thread quality because of its low coefficient of friction, but the chrome plating wears and peels off. There is a problem that the life is short because it is easy.

On the other hand, although the fiber guide made of alumina ceramics has high hardness and little wear, there is a problem that the fiber quality is likely to be deteriorated due to the large resistance to the fiber. In addition, although the titania ceramics do not easily deteriorate the yarn quality, they are easily worn.

Therefore, as disclosed in Japanese Patent Publication No. 52-48647, it has been considered that the crystal is rounded by firing the fiber guide made of alumina ceramics and then firing it again. It is difficult to make the crystal round by the method, and there is a problem that the obtained sintered body has large surface irregularities and the surface becomes too rough.

Therefore, there has not been a fiber guide having both properties of not deteriorating the yarn quality, excellent wear resistance and long life.

As described above, alumina ceramics satisfies the conditions of excellent wear resistance and long life. Therefore, if the surface quality can be improved to prevent yarn quality deterioration, all the required characteristics will be satisfied. Therefore, as a result of various experiments on the surface condition of alumina ceramics, voids such as pores and holes and grain boundaries exist in polycrystalline ceramics such as alumina, and the thread edge is deteriorated by the sharp edge of the voids. I understood. It was also found that the crystal grain boundaries similarly become resistance during sliding, which not only causes deterioration of the yarn quality, but also causes the crystal grain boundaries due to impurities to be easily worn and reduce wear resistance.

Therefore, an object of the present invention is to improve the surface condition of a fiber guide made of alumina ceramics so as to obtain a fiber guide which does not deteriorate the yarn quality and is excellent in wear resistance.

[0011]

The first aspect of the present invention is as follows.
The sliding surfaces of the at least the fibers of the fiber guide is mainly composed of Al ₂ O ₃ of 99.9 wt%, average grain size of Al ₂ O ₃ is formed in the following ceramics 2 [mu] m, 30 [mu] m on the sliding surface It is characterized in that there are no voids that exceed. The sliding surface with the fibers means a surface that slides or may slide with the fibers when used as a fiber guide.

Further, such a fiber guide is made of Al ₂ O.
₃ Purity is 99.9% by weight or more, and the average particle size is 0.1 to 0.
After forming 5 μm alumina raw material powder into a predetermined shape, 1
It can be manufactured by a process of firing at 400 to 1700 ° C.

Alternatively, it can also be obtained by applying a slurry made of the above-mentioned high-purity fine raw material to the sliding surface of the fiber guide made of low-purity alumina or the like on the sliding surface with the fiber and then firing it.

That is, the first aspect of the present invention is to reduce voids and grain boundaries in the sintered body by using a highly pure and extremely fine Al ₂ O ₃ raw material.

Here, the Al ₂ O ₃ content is set to 99.9% by weight or more because if it is less than 99.9% by weight, the yarn quality is likely to be deteriorated due to the existence of crystal grain boundaries. Is. Then, the high-purity alumina raw material is molded and sintered without adding a sintering aid. Although such a high-purity raw material has poor sinterability, it can be fired at a relatively low temperature by making the raw material powder extremely fine as described later. As a component other than Al ₂ O ₃ , Mg as an impurity was used.
It may contain O or SiO ₂ in a total amount of 0.1% by weight or less.

The average particle size of the raw material powder is 0.1 to 0.
The reason why the particle size is 5 μm is that it is extremely difficult to manufacture a powder having a particle size of less than 0.1 μm, whereas if it exceeds 0.5 μm, not only the effect of reducing voids is poor, but also the sinterability of the high-purity alumina raw material deteriorates. This is because. Moreover, the reason why the average crystal grain size of the final sintered body is set to 2 μm is that if the average crystal grain size exceeds 2 μm, not only the voids increase, but also the hardness decreases and the wear resistance decreases.

Further, according to the present invention, by using the highly pure and fine raw material as described above, voids having a diameter of 30 μm or more do not exist. This has a void of 30μ
This is because if it exceeds m, the yarn is likely to be damaged, and preferably voids having a diameter of 10 μm or more do not exist.

Further, if the firing temperature of the alumina ceramics of the present invention is less than 1400 ° C., the densification is insufficient, while if it exceeds 1700 ° C., crystals grow too much,
In both cases, the hardness of the sintered body decreases, so 1400 to 17
Within the range of 00 ° C.

Next, the second aspect of the present invention is that at least the sliding surface of the fiber guide with respect to the fibers is made of 90% by weight or more of a ceramic containing Al ₂ O ₃ as a main component, and the average crystal grain of Al ₂ O ₃ is Diameter is 3 ~ 20μm, Vickers hardness is 1800k
It is characterized in that voids exceeding 30 μm at gf / mm ² or more do not exist.

In this fiber guide, an alumina raw material having an Al ₂ O ₃ purity of 90% by weight or more is molded into a predetermined shape, and then primary firing is performed at 1300 to 1600 ° C. in an air atmosphere, and then argon, nitrogen, etc. Inert atmosphere gas pressure 18
1400 to 1900 ° C at 00 to 2200 kgf / cm ²
It can be manufactured by the step of secondary firing at the temperature of.

That is, according to the second aspect of the present invention, after the ordinary firing is performed, the secondary firing is performed under a gas pressure such as hot isostatic pressure treatment (HIP) to sinter and sinter with extremely high density. The voids in the aggregates are made small, and the crystal grains are appropriately grown to reduce the crystal grain boundaries.

In the present invention, the Al ₂ O ₃ content is required to be 90% by weight or more for increasing the hardness, but preferably 99% by weight or more. As components other than Al ₂ O ₃ , sintering aids such as SiO ₂ and MgO may be contained in a total amount of 10 wt% or less, preferably 1 wt% or less. Further, Cr ₂ O ₃ or other metal oxide may be contained as a colorant in a total amount of 0.1 to 2% by weight, preferably 0.1 to 1% by weight.

Regarding the average crystal grain size of the sintered body,
If it is less than 3 μm, the effect of reducing the crystal grain boundaries is poor because the crystal growth is insufficient, while if it exceeds 20 μm, the strength decreases, so the average crystal grain size is 3 to 20 μm.
Within the range of m. In the present invention, since the firing is performed under a gas pressure to sinter very finely, the Vickers hardness of the sintered body is 1 even if the crystal grain size is large (3 μm or more).
The hardness can be as high as 800 kgf / mm ² or more.

Then, by carrying out the gas pressure firing as described above, voids having a diameter of 30 μm or more do not exist. This is because when the void exceeds 30 μm, damage to the yarn is likely to occur, and the diameter is preferably 1
Make sure there are no voids greater than 0 μm.

Further, if the secondary firing temperature under the gas pressure of the alumina ceramics of the present invention is less than 1400 ° C., the effect of reducing voids is poor, while if it exceeds 1900 ° C., crystals grow too much and the sintered body Therefore, the hardness is set to fall within the range of 1400 to 1900 ° C.

[0026]

EXAMPLE 1 An example of the first invention will be described below.

Purity of 99.90-9 as alumina raw material
A powder having an average particle size of 0.1 to 0.5 μm at 9.99% by weight was used. This raw material powder was processed by adding a binder suitable for each process of dry press molding, injection molding, and extrusion molding, and molded into a rod shape. The obtained molded body was calcined at 400 to 600 ° C. for degreasing, and then fired at various temperatures of 1300 to 1800 ° C. in the air atmosphere to obtain the rod-shaped fiber guide 1 shown in FIG.

On the other hand, as a comparative example, the Al ₂ O ₃ content is 9
A conventional fiber guide made of alumina ceramics using a raw material of 6% and an average particle diameter of 2 μm was prepared.

The density, average crystal grain size, Vickers hardness, and void diameter of the sintered body were measured for each. The void diameter was measured on a mirror-finished surface using a scanning electron microscope at a magnification of 1,500 times. The results are shown in Table 1.
As shown in.

From Table 1, as a comparative example, a raw material having a low purity and a large grain size (No. 7) has an average crystal grain size of more than 2 μm, and voids have an average grain size of 50 μm.
There was a void as large as about μm and a diameter close to 100 μm. In addition, even if a high-purity raw material is used and the firing temperature is as low as 1300 ° C (No. 1), the Vickers hardness is 1600 kgf / mm because the densification is insufficient.
^{If the} firing temperature is as low as ² or less and conversely as high as 1800 ° C (No. 6), the average crystal grain size is 2 μm due to grain growth
And the Vickers hardness was as low as 1600 kgf / mm ² or less.

On the other hand, the embodiment of the present invention (N
o. 2 to 5), the average crystal grain size is 1 to ² μm, the Vickers hardness is as high as 1900 to 2000 kgf / mm ^2, and only voids within the range of 1 to 10 μm are observed, and voids exceeding 10 μm exist. There wasn't.
This is because there are few crystal grain boundaries because a high-purity raw material is used,
Moreover, since it is a fine raw material, it is considered that voids can be reduced.

[0032]

[Table 1]

Next, an experiment was conducted in which the fiber 2 was slid on the fiber guide 1 as shown in FIG. As a comparative example, No. 1 in Table 1 was used. 7 and No. 7 as an example of the present invention. Using the fiber guide No. 4, fibers each having a yarn thickness of 75 denier were slid at a yarn speed of 1000 m / min using a thread polyester. After the test,
The abrasion of the fiber guides, the yarn breakage of the fibers, the occurrence of snow such as abrasion chips and fluff were compared. The results are shown in Table 2.

From these results, it is clear that the use of the fiber guide of the present invention causes almost no yarn breakage or snow even for fibers running at high speed, and the wear of the guide itself can be extremely reduced.

In the above embodiment, an example in which the entire fiber guide is formed by using a high-purity and fine raw material is shown. However, it is formed by using a low-purity raw material in advance and only the sliding surface is formed. The same applies to the case where a slurry of high purity and fine raw material is applied and fired.

[0036]

[Table 2]

Embodiment 2 Hereinafter, an embodiment of the second invention will be described.

As an alumina raw material, the purity is 99.5 to 99.
7% by weight, average particle size 0.6 μm, specific surface area 8 m ² / g
The raw material powder has a mean particle size of 0.6 μm and a specific surface area of 8 m ² /
0.1 to 2.0% by weight of chromium oxide (Cr ₂ O ₃ ) powder was added. This raw material powder was processed by adding a binder suitable for each process of dry press molding, injection molding, and extrusion molding, and molded into a rod shape. The obtained molded body was calcined at 400 to 600 ° C. to degrease it, and was then primarily fired at a temperature of 1300 to 1600 ° C. in an air atmosphere.
Next, the obtained sintered body was subjected to secondary firing by hot isostatic pressing (HIP) in an Ar gas atmosphere. The gas pressure during the secondary firing was 1800 to 2200 kgf / cm ² , and the firing temperature was various temperatures of 1300 to 2000 ° C.
The rod-shaped fiber guide 1 shown in FIG.

On the other hand, as a comparative example, the one prepared when the above-mentioned primary firing was completed without performing the secondary firing was prepared.

The density, average crystal grain size, Vickers hardness, and number of voids of each sintered body were measured. The number of voids was determined by observing a mirror-finished surface of 9.4 cm ² with a 30 × optical microscope and counting the number for each void diameter. The results are shown in Table 3.

From Table 1, in the comparative example (No. 17) in which the secondary firing is not performed, 60 to 70 voids having a diameter of 30 to 49 μm and 5 to 15 voids having a diameter of 50 μm or more are large voids. Existed. In addition, the secondary firing temperature of 1300 ° C. (No.
In 11), similarly large voids were present. on the other hand,
When the firing temperature is 2000 ° C. (No. 16), the average crystal grain size of the sintered body exceeds 20 μm, and the Vickers hardness is 1400.
It was as low as khgf / mm ² or less.

On the other hand, those having a firing temperature of 1400 to 1900 ° C., which is an example of the present invention (No. 12 to 15)
Had an average crystal grain size of 3 to 20 μm, a Vickers hardness of 1800 kgf / mm ² or more, and 3 to 7 voids of 29 μm or less, or no void exceeding 30 μm. It is considered that this is because the sintered body was densified by performing the hot isostatic pressure treatment and the crystal grain boundaries were decreased because the crystals were appropriately grown.

Further, although the primary calcined product (No. 17) had a pink color due to the addition of chromium oxide, the present invention examples (Nos. 12 to 15) were subjected to hot isostatic pressure treatment.
Has a light-transmitting property and exhibits a ruby-like coloration.

[0044]

[Table 3]

Next, an experiment was conducted in which the fiber 2 was slid on the fiber guide 1 as shown in FIG. As a comparative example, No. 1 in Table 3 was used. 17 and No. 17 as an example of the present invention. Using a fiber guide of No. 14, fibers having a thickness of 75 denier made of thread polyester were slid at a thread speed of 1000 m / min. The sliding characteristics of the fiber guide were evaluated by the frictional resistance during sliding, and the yarn quality was evaluated by the presence or absence of yarn breakage or snow after the test.
The results are shown in Table 4.

From these results, it is clear that the use of the fiber guide of the present invention has a high sliding property even for fibers running at a high speed, and since the yarn breakage and the snow hardly occur, the high yarn quality can be maintained. Recognize. Further, since the fiber guides of the examples of the present invention had a ruby color, it was easier to identify the fibers than the comparative examples.

[0047]

[Table 4]

Although the rod-shaped fiber guide 1 is shown in the above embodiments, it goes without saying that the fiber guide 1 can have various known shapes.

[0049]

As described above, according to the present invention, the purity is 9
Al with an average particle size of 0.1 to 0.5 μm at 9.9% by weight or more
_{Using 2} O ₃ raw material, the average crystal grain size of Al ₂ O ₃ is 2 μm
By configuring the alumina ceramic fiber guide so that voids of 30 μm or more do not exist below, damage to the fiber can be reduced and deterioration of the yarn quality can be prevented while maintaining high wear resistance. Can be guided with high accuracy.

Further, according to the present invention, the Al ₂ O ₃ raw material having a purity of 90% by weight or more is used, and the secondary calcination under the gas pressure is carried out after the normal pressure calcination, so that the average crystal grain size of Al ₂ O ₃ is 3 to 3. 20μ
m, Vickers hardness of 1800 kgf / mm ² or more,
By configuring the alumina ceramic fiber guide so that voids of 30 μm or more do not exist, damage to the fiber can be reduced and deterioration of the yarn quality can be prevented while maintaining high wear resistance, and the fiber can be highly accurate. Can be guided to.

As a result, it is possible to satisfactorily guide high-speed running fibers having a yarn speed of 1000 m / min or more,
High-quality fibers can be efficiently produced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a fiber guide of the present invention.

[Explanation of symbols]

 1: Fiber guide 2: Fiber

Claims (5)

[Claims] 1. A sliding surface with fibers, which comprises 99.9% by weight or more of Al ₂ O ₃ as a main component and an average grain size of Al ₂ O ₃ of 2 μm or less. To 30
A fiber guide characterized by the absence of voids exceeding μm. 2. Al ₂ O ₃ purity of 99.9% by weight or more,
A method for producing a fiber guide, which comprises the steps of molding an alumina raw material powder having an average particle diameter of 0.1 to 0.5 μm into a desired guide shape and then firing the powder at 1400 to 1700 ° C. 3. A slurry comprising alumina raw material powder having an Al ₂ O ₃ purity of 99.9% by weight or more and an average particle size of 0.1 to 0.5 μm on the sliding surface of the ceramic fiber guide with respect to the fibers. A method for producing a fiber guide, which comprises a step of applying the above composition and firing at 1400 to 1700 ° C. 4. The sliding surface with the fiber is 90% by weight or more of Al.
₂ O ₃ as a main component, and the average crystal grain size of Al ₂ O ₃ is 3 to
Vickers hardness of 1800 kgf / mm ^{2 at} 20 μm
A fiber guide which is made of the above ceramics and has no voids exceeding 30 μm on the sliding surface. After wherein Al ₂ O ₃ purity was molded 90 wt% or more alumina raw material into a predetermined shape, 130 in the atmosphere
Primary calcination at 0 to 1600 ° C., then gas pressure of 1800 to 2200 kgf / cm in an inert atmosphere such as argon and nitrogen
^{2. A} method for producing a fiber guide, which comprises the step of secondary firing at a temperature of 1400 to 1900 ° C. in 2.