JPH08134789A - Drier canvas for papermaking - Google Patents

Abstract

PURPOSE: To prevent electrostatic hinderance in a drier canvas used in a papermaking drier part. CONSTITUTION: In this drier canvas 1 for papermaking comprising subjecting a fiber web 3 to needle punching treatment onto base fabric 2, an electrically conductive conjugate fiber 4 in which two-components are conjugated, arranging an electrically conductive fiber containing carbon fine particles in a nylon fiber is mixed into the fiber web 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper-making dryer canvas, and more particularly to a paper-making dryer canvas which is used in the dry part of a paper machine and which has antistatic measures against static electricity, and particularly to a base fabric. The present invention relates to a dryer canvas formed by needle punching a fiber web.

[0002]

2. Description of the Related Art A dryer canvas for papermaking used in a dry part of a paper machine is charged by friction due to a difference in surface speed between the constituent fibers of the dryer canvas, the paper to be made of paper, and a drying roll. Phenomenon occurs,
Due to the generation of static electricity, dirt such as paper dust and oil mist easily adheres to the surface of the dryer canvas. As a result,
There is a problem that adversely affects the quality of paper materials to be made.

In order to solve such a problem, for example, in Japanese Utility Model Application Laid-Open No. 508203/1982, conductive fibers such as carbon fibers and metal fibers are provided on both sides or one side of a base fabric constituting a dryer canvas for papermaking. A method of imparting antistatic properties to a papermaking dryer canvas by needle-punching the mixed fiber web is described.

Further, in Japanese Utility Model Laid-Open No. 6-6496, a fiber web used as a surface layer constituting member of a dryer canvas for papermaking is provided with a metal coating film of the same quality as the fiber forming the fiber web and on the surface. A method for imparting antistatic properties by mixing the fibers contained therein is described.

Furthermore, a woven fabric, which is prepared by using a yarn mixed with a conductive material as described in Japanese Utility Model Laid-Open No. 2-61999, in which antistatic measures are taken, is used as a base fabric of a needle canvas. Needling fiber webs are commonly used.

[0006]

[Problems to be Solved by the Invention]
In the papermaking dryer canvas described in the publication, since conductive fibers such as carbon fibers and metal fibers are mixed in the fiber web, the synthetic fibers and the conductive fibers that are blended as the main components of the fiber web. Since the physical properties of, for example, flexibility are significantly different, surface properties equivalent to those of a papermaking dryer canvas in which the surface side is formed only from synthetic fiber webs cannot be obtained, and there are many cases where spots etc. occur on the paper surface. It was

On the other hand, in the dryer canvas for papermaking described in Japanese Utility Model Laid-Open No. 6-6496, the bending strength is repeatedly applied in the dry part, so that the coating strength decreases with time, and the fiber surface is covered with metal. In addition to the problem that the coating film is easily peeled off, contact with wet paper or chemicals containing water causes metal ions to elute from the metal coating film, causing poor quality due to metal ion adsorption on the paper material that is produced. The problem of causing it remains unsolved today.

Further, in the papermaking dryer canvas described in Japanese Utility Model Laid-Open No. 2-61999, the electric potential becomes high around the yarn mixed with the conductive substance, and fine dust is apt to be concentrated on this part. However, there are some defects such that the discharge phenomenon easily occurs and the discharge phenomenon easily occurs. When the discharge phenomenon becomes severe, the individual fibers constituting the fiber web may be heated and melted, making it impossible to use the papermaking dryer canvas for a long period of time.

[0009] A main object of the present invention is to provide a papermaking dryer canvas having improved antistatic performance capable of solving the practical problems found in the prior art.

[0010]

Means for Solving the Problems As a means for solving the above problems, the present invention provides a dryer canvas for papermaking, which comprises needle-punching a fiber web on a base fabric, wherein the fiber web contains a conductive material containing carbon fine particles in nylon fibers. The present invention provides a dryer canvas for papermaking, in which a conductive composite fiber of a two-component composite in which a functional fiber is arranged is mixed.

[0011]

[Function] By mixing needle-punched fiber web on a base cloth with a conductive composite fiber of a two-component composite in which conductive fibers containing carbon fine particles are arranged in nylon fiber, surface characteristics of a dryer canvas for papermaking, Durability is maintained at about the same level as in the case where no conductive fiber is contained, and the dryer canvas for papermaking retains antistatic performance that is practically satisfactory.

[0012]

EXAMPLES Hereinafter, specific examples of the present invention will be described based on the examples of FIGS. 1 to 4 and Tables 1 to 5.

The papermaking dryer canvas (1) is shown in FIG.
As shown in (A), after overlaying the fiber web layer (3) on the paper-contacting surface side of the base fabric layer (2) woven in the double woven structure, needle punching is performed together with the base fabric layer (2). By applying the above, the base fabric layer (2) and the fiber web layer (3) are joined in an integral structure.

As shown in Table 1, the base cloth layer (2) comprises a polyester monofilament having a diameter of 0.40 mm, a warp density of 84.4 filaments / 25.4 mm, and a weft density of 15.3-1.
Manufactured by weaving a double weave design with a weave density of 5.6 x 2 / 25.4 mm.

On the other hand, as shown in Table 1, the fiber web layer (3) is composed of nylon fiber 4 of single fiber denier 15d.
Into a fiber web consisting of 5 to 55 parts by weight and 40 parts by weight of acrylic fiber of 10 d of single fiber denier, 5 to 15 parts by weight of 2.5 d of single fiber denier and 51 mm of conductive composite fiber MEGA III having a constant cut length of 51 mm are mixed. It is manufactured by Mega III is a trade name of a conductive composite fiber manufactured by Unitika Ltd., and the conductive composite fiber (4) is a fiber containing carbon fine particles in a nylon fiber (4A) as shown in FIG. 1 (B). (4B) is arranged. The carbon fine particle-containing fiber (4
The content of B) is preferably as small as possible within the range effective for preventing static electricity. The ratio of the conductive composite fiber filaments (4) mixed in the fiber web layer (3) is adjusted so as to account for 3 to 20 parts by weight in the total weight of the fiber web layer (3).

[0016]

[Table 1]

[0017]

[Table 2]

Although Table 1 shows three types of examples, Table 2 shows comparative examples in order to clarify the difference in action and effect between the present invention and the prior art.

In the papermaking dryer canvas (1) shown in FIG. 1 (A), the fiber web layer (3) containing the conductive composite fiber mega III is provided only on the paper-contacting side of the base fabric layer (2).
However, it is also possible to superimpose the fiber web layers (3) on the upper and lower surfaces of the base fabric layer (2) if necessary.

In order to evaluate the antistatic performance of the papermaking dryer canvas (1) obtained in the present invention, a resistance measuring device shown in FIG. 2 was prepared, and the electrodes (6) and (7) and the conductive rubber sheet ( 8) Hold the sample (10) of the papermaking dryer canvas (1) between (9) and apply a predetermined rated current between the electrodes while using the super-insulator (5) to measure the resistance and specific resistance (volume). The specific resistance value) was measured. The measurement results are collectively displayed in Table 3. The size of the sample (10) is 90 mm in length.
mm, width 50 mm, the resistance value of the conductive composite fiber mega III itself is 8.4 × 10 ⁷ (Ω), and the specific resistance value is 1.2 × 1.
It is 0 ⁴ (Ω · cm).

[0021]

[Table 3]

From the measurement results shown in Table 3, Examples 1 to 3
It is understood that the sample (10) shown in (1) has a smaller specific resistance value than the sample prepared as the comparative example, and the antistatic performance of static electricity is maintained at a good level.

In order to evaluate the antistatic performance of the papermaking dryer canvas (1), a width of 15 cm and a length of 3 are used.
A 60 cm sample (10) was prepared, mounted on a running test machine (12) shown in FIG. 3, and a running speed (Vel.) Of 50 m / mi was applied with a tension of 1.0 kg / cm being applied.
n. 100 m / min. 150 m / min. And 200
m / min. The charging voltage (kv) was measured as the maximum voltage at 5 minutes, 10 minutes, and 15 minutes after the start of the test for each traveling speed. The measurement results are displayed collectively in FIG. The running test machine (12) shown in FIG. 3 has a weight (w) and a pressure roller (13) as means for adjusting the tension applied to the sample (10), and also has the sample (10). ) Is provided above the running range of the static charge measuring device [(11) manufactured by Shishido Electrostatics Co., Ltd., trade name "STATYLON-M"]. Charge voltage measuring device (1
A voltage sensor (11A) is connected to 1) while maintaining a distance L ₀ from the upper surface of the sample (10). The relative positions of the sample (10) and the electrostatic voltage measuring device (11) are described for reference. L ₀ is set to 5 cm, L ₁ is set to 57 cm, L ₂ is set to 110 cm, and L ₃ is set to 50 cm.

Samples (1
It is understood that the charged voltage of 0) is greatly reduced as compared with the sample prepared as the comparative example.

[0025]

EFFECTS OF THE INVENTION Since the content of carbon fine particles contained in the electroconductive composite fiber is small, the surface properties of the fibrous web contacting the wet paper can be maintained at a level almost equal to that of the fibrous web containing no electroconductive fiber. To be done. As a result, the deterioration of the surface characteristics of the papermaking dryer canvas due to the lack of flexural strength and abrasion resistance is avoided, and it is possible to use the dryer for a long period of time. Further, since the antistatic performance and the surface characteristics of the fiber web are improved, quality defects such as adhesion of fine dust to the surface of the paper material or generation of papermaking spots due to the generation of static electricity are reduced and a remarkable effect is obtained. To be demonstrated. According to the present invention, a relatively small amount of conductive composite fibers are dispersed and arranged in the fiber web layer, whereby an antistatic region is formed substantially uniformly over the entire paper-contacting surface of the papermaking dryer canvas. A substantially perfect solution is provided for the disadvantage that the charged voltage is locally high on the surface of the canvas and dust is concentrated on this part.

[Brief description of drawings]

FIG. 1A is a partial vertical cross-sectional view of a papermaking dryer canvas according to the present invention, and FIG. 1B is an enlarged cross-sectional view of a conductive composite fiber.

FIG. 2A is a plan view of a resistance measuring device, and FIG. 2B is a partial vertical cross-sectional view thereof.

FIG. 3 is a front view of a running test machine for measuring a charged voltage.

FIG. 4 is a diagram showing a charged voltage-canvas speed.

[Explanation of symbols]

 1 Papermaking Dryer Canvas 2 Base Fabric Layer 3 Fiber Web Layer 4 Conductive Composite Fiber

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display part D04H 1/46 Z

Claims (1)

[Claims] 1. A paper-making dryer canvas in which a fibrous web is needle-punched on a base fabric, wherein a bicomponent electroconductive composite fiber in which electroconductive fibers containing carbon fine particles are arranged in nylon fibers is arranged in the fibrous web. A dryer canvas for papermaking characterized by being mixed.