JPH10298894A - Reduction of wear of papermaking wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce wear of a plastic wire for papermaking and to extremely prolong a life thereof by carrying out the papermaking of a pulp slurry containing a filler formulated therewith after addition of alumina and/or zirconia having a specific average particle diameter to the pulp slurry containing the filler. SOLUTION: This method for reducing the wear of a papermaking wire comprises addition of alumina and/or zirconia having a particle diameter larger than the average particle diameter of a filter formulated with a pulp slurry but smaller than 50 μm to the pulp slurry containing the filter such as talc and kaolin, especially heavy calcium carbonate and precipitated calcium carbonate formulated therewith, and papermaking of the added slurry. The addition amount of the alumina and/or zirconia is 0.03-12 wt.% based on the filler formulated with the pulp slurry. The added alumina and/or zirconia acts as a runner in the contact of the paper with the plastic wire and reduces the wear by the abrasion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing abrasion of a papermaking wire, and more particularly to a method for reducing abrasion of a plastic wire.

[0002]

2. Description of the Related Art Generally, papermaking is performed by adding an internal filler to a pulp fiber slurry-based paper stock for the purpose of increasing the opacity, whiteness or smoothness of the obtained paper product and further improving the formation. Is carried out. And usually, as the internal filler, talc, kaolin, heavy calcium carbonate,
Light calcium carbonate or the like is used, and these internal fillers are used alone or in combination depending on the use and purpose of the product. Papermaking is to form a paper layer by discharging extremely low concentration paper stock (pulp fiber slurry) from an inlet onto a continuously running metal wire or plastic wire and dewatering. In recent papermaking methods, the use of plastic wires has become mainstream.

[0003] Plastic wires are expensive, and their use over as long a period as possible is an important factor in terms of productivity and cost. In addition, it has been known that the abrasion of plastic wires has a great difference depending on the type of filler added to the stock. That is, in the case of talc or kaolin used as an internal filler in any of an acidic papermaking method and a neutral papermaking method, the abrasion of the plastic wire is relatively small. On the other hand, the use of calcium carbonate as an internal filler in the case of neutral paper, etc., especially when heavy calcium carbonate is used, the plastic wire is severely damaged,
There is a drawback that the wire life is shortened. For this reason, use of light calcium carbonate, which is used in combination with talc or the like, or whose wear on plastic wires is relatively small, is increasing. On the other hand, as a method for reducing the abrasion of a plastic wire for papermaking when heavy calcium carbonate is used as an internal filler, for example, JP-A-8-14
Japanese Patent No. 4190 proposes a method of adding silica sand to paper stock, but at present, the desired reduction effect is not obtained in the present invention.

[0004]

In recent years, a paper maker that manufactures paper and sheets, etc., efficiently produces products having excellent quality in consideration of operability and economic efficiency according to the application and purpose. It is essential. Considering the plastic wire and the internal filler from the above viewpoints, especially the internal filler (hereinafter simply referred to as filler)
When (heavy) calcium carbonate is used, how to make an expensive plastic wire last is an important issue from the viewpoint of productivity improvement and cost. The present inventors have intensively studied a method of extending the life of a plastic wire as long as possible in a combination of a plastic wire and a filler, mainly (heavy) calcium carbonate. As a result, the present invention reduces the wear of plastic wires very effectively by supplementally adding a specific mineral pigment to the stock containing filler.
It is intended to provide a method for extending the life of a wire.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method for reducing abrasion of a papermaking wire, which comprises making a paper using at least alumina or / and zirconia added to a pulp slurry to which a filler is internally added. It is a method of reducing.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for preparing a paper stock mainly composed of pulp fibers containing a filler and discharging the paper stock onto a continuously running plastic wire for papermaking. The present invention relates to a method for extending the life of a plastic wire. Particularly, the use of (heavy) calcium carbonate as a filler and the addition of a small amount of alumina and / or zirconia to a stock material make the life of a plastic wire extremely effective. It is found that it grows. Of course, the method according to the present invention is also effective for fillers other than calcium carbonate. It is not always clear why the combined use of a small amount of alumina and / or zirconia extends the life of the plastic wire, but it is estimated as follows.

That is, adhesion and ablation are pointed out as the main causes of plastic wire wear. Here, the adhesion refers to the adhesion that occurs at the true contact point between the wire and the filler. With continuous running (sliding) of the wire, adhesion occurs at the true contact point one after another. At the moment, it progresses to cutting. It is estimated that as the number of true contact points increases, the degree of wear increases accordingly. On the other hand, abrasion is caused by wear caused by micro-cutting action that scratches the wire as the wire travels because surface protrusions of the filler itself and filler particles themselves are inserted or pierced into the plastic wire. That is. In particular, when heavy calcium carbonate, whose surface projections are sharp and large, is used for the filler, the wear of the plastic wire is presumed to be more severe.

According to the method of the present invention, alumina and / or zirconia having a particle size relatively larger than that of the filler are added to the filler in an amount of 0.03 to 12% by weight relative to the solid content.
By adding, alumina particles having a large particle diameter first on the plastic wire surface due to the particle diameter difference,
Alternatively, the contact of the zirconia particles reduces the chance that particles such as heavy calcium carbonate used as a filler are in direct contact with the plastic wire. As a result, the true points of contact and the chance of contact between the filler and the plastic wire are reduced.Furthermore, alumina particles and zirconia particles have few surface protrusions as compared with heavy calcium carbonate and have By exhibiting such an effect, friction is reduced,
It is also presumed that wear due to ablation, that is, cutting wear is unlikely to occur.

In the present invention, the above-mentioned specific amount of alumina and / or zirconia is added to heavy calcium carbonate, which has the most adverse effect, as well as ordinary filler such as talc and kaolin, particularly to plastic wires. They have found for the first time that the wear of plastic wires is extremely effectively suppressed, and the life of the wires can be extended efficiently.

As the alumina and / or zirconia added to the stock, the average particle size of the alumina and / or zirconia is larger than the primary particle size of the filler added to the stock, as well as the alumina and / or zirconia. Preferably, zirconia particles are used. Generally, the average particle size of the filler used is in the range of 3-20 μm. Therefore, the upper limit of the average particle diameter of alumina and / or zirconia added to the filler in the present invention is not specified, but
Considering the paper quality of the final product, the upper limit is 50μ
m. By the way, if it exceeds 50 μm, there is an effect of suppressing (reducing) wire abrasion, but there is a possibility that the quality of the obtained paper product may be deteriorated.

When the amount of the filler is less than 0.03% by weight relative to the solid content, the effect of suppressing (reducing) abrasion of the plastic wire desired by the present invention may not be obtained. On the other hand, if it exceeds 12% by weight, there is a concern that the effect on the paper quality may be caused.

[0012]

EXAMPLES The present invention will be specifically described below with reference to examples. Of course, the present invention is not limited to them. In addition,% in an example is "weight%" unless there is particular notice.
Is shown. The measurement conditions and the like were as follows.

(Measurement of Average Particle Diameter) A Microtrac particle size analyzer (Nikkiso Co., Ltd.) was used to measure the average particle diameter of the filler.

(Abrasion test of plastic wire) NF
A wire abrasion test was carried out using an abrasion tester (Nippon Filcon) under the following conditions. Sample concentration: 0.75%, sample amount: 5 liters, wire type: OSH-80 [(Nippon Filcon Co., Ltd./plastic wire) / wire size: 50 × 150 mm], roll material: ceramic, roll diameter: 60 mm, roll rotation Number: 1500 rpm / min, contact angle: 111 degrees, weight: 800 g, test time: 0.5 hour. As for the wire abrasion test using light calcium carbonate and talc, the sample concentration was 1.5% and the test time was 2 hours.
The procedure was performed under the same conditions as above except that the time was changed. Degree of wear (amount) = [weight of wire before test]-[weight of wire after test] (unit: mg)

Example 1 (Preparation of sample) 99.7% of heavy calcium carbonate (SL-13 / Takehara Chemical Industry Co., Ltd., average particle size: 5.7 μm), alumina (AS-50 / Showa Denko Co., Ltd., average particle size) Diameter: 8.8
μm) A material composed of 0.3% was stirred and dispersed through water with a homodisper to prepare a filler slurry having a solid content concentration of 0.75%. The filler slurry thus obtained was subjected to a 30-minute wear test according to the above conditions.
Table 1 shows the obtained results.

Example 2 A test was carried out in the same manner as in Example 1 except that 97.0% of heavy calcium carbonate and 3.0% of alumina were used in the preparation of the sample of Example 1. The results are shown in Table 1.

Example 3 A test was carried out in the same manner as in Example 1 except that the preparation of the sample of Example 1 was changed to 90.0% of heavy calcium carbonate and 10.0% of alumina. The results are shown in Table 1.

Example 4 In the preparation of the sample of Example 1, alumina was replaced with zirconia (RZ-8C @ 325F / Showa Denko KK ... average particle diameter 1).
The test was performed in the same manner as in Example 1 except that the thickness was changed to 4.4 μm), and the obtained results are shown in Table 1.

Example 5 In the preparation of the sample of Example 2, alumina was replaced with zirconia (RZ-8C @ 325F / Showa Denko KK ... average particle diameter 1).
The test was performed in the same manner as in Example 2 except that the thickness was changed to 4.4 μm), and the obtained results are shown in Table 1.

Example 6 In the preparation of the sample of Example 1, heavy calcium carbonate was 99.95% of light calcium carbonate (TNC-C30 / Toyo Denka Kogyo KK ... average particle size: 3.7 μm) and alumina was 0.05 %, And a test was performed in the same manner as in Example 1 except that the solid content concentration was changed to a filler slurry of 1.5%, and the test time was changed to 2 hours.
Table 1 shows the obtained results.

Example 7 A test was performed in the same manner as in Example 6 except that the light calcium carbonate was changed to 99.7% and the alumina was changed to 0.3% in the preparation of the sample of Example 6, and the results were obtained. The results obtained are shown in Table 1.

Example 8 In the preparation of the sample of Example 1, heavy calcium carbonate was replaced with talc (NK talc / Chuo Kaolin Co., Ltd., average particle size: 1).
3.8 μm) 97.0%, alumina is zirconia (RZ
-8C @ 325F / Showa Denko KK ... Average particle diameter 14.4
μm) was changed to 3.0%, and the solid content concentration was 1.5%.
%, And the test was performed in the same manner as in Example 1 except that the test time was changed to 2 hours. The results obtained are shown in Table 1.

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that in the preparation of the sample of Example 1, heavy calcium carbonate was set to 100% and alumina was not added. The results are shown in Table 1.

Comparative Example 2 In the preparation of the sample of Example 1, the whole amount of heavy calcium carbonate was converted to light calcium carbonate (TNC-C30 / Toyo Denka Kogyo Co., Ltd .: average particle diameter 3.7 μm), and alumina was added. And a filler slurry with a solid concentration of 1.5%,
The test was performed in the same manner as in Example 1 except that the test time was changed to 2 hours, and the obtained results are shown in Table 1.

Comparative Example 3 In the preparation of the sample of Comparative Example 2, light calcium carbonate was added to talc (NK talc / Chuo Kaolin Co., Ltd., average particle size: 1).
(3.8 μm) A test was conducted in the same manner as in Comparative Example 2 except that 100% was used, and the obtained results are shown in Table 1.

[0026]

[Table 1]

[0027]

As is evident from the results in Table 1, the combination of the filler and the auxiliary mineral pigment in the method of the present invention, especially when the filler is heavy calcium carbonate or light calcium carbonate, is significantly different from the plastic wire for papermaking. It is possible to achieve a long service life.

Claims (4)

[Claims] 1. A method for reducing the abrasion of a papermaking wire, wherein the papermaking is carried out by using a stock obtained by adding alumina or / and zirconia to a pulp slurry to which at least a filler is internally added. 2. The method for reducing abrasion of a papermaking wire according to claim 1, wherein the amount of alumina and / or zirconia added is 0.03 to 12% by weight based on the solid content of the filler. 3. The paper-making wire according to claim 1, wherein alumina and / or zirconia having an average particle diameter larger than the average particle diameter of the internal filler and smaller than 50 μm is used as the alumina and / or zirconia. How to reduce. 4. The method for reducing abrasion of a papermaking wire according to claim 1, wherein the papermaking wire is a plastic wire.