JP4056580B2 - Dryer canvas for papermaking - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a paper machine dryer canvas, and more particularly to a paper machine dryer canvas which is used by taking measures against static electricity prevention in a dry part of a paper machine, and in particular, a fiber web is needle punched on a base fabric.
[0002]
[Prior art]
In a paper dryer dryer canvas used in a dry part of a paper machine, a charging phenomenon occurs due to friction caused by a difference in surface speed between the constituent fibers, the paper material to be produced, and the drying roll, and the static electricity. Occurrence of dirt and dust such as paper dust and oil mist tends to adhere to the surface of the dryer canvas. As a result, there is a problem that adversely affects the quality of paper to be produced.
[0003]
In order to solve such problems, for example, Japanese Utility Model Laid-Open No. 50-8203 discloses a fiber in which conductive fibers such as carbon fibers and metal fibers are mixed on both sides or one side of a base fabric constituting a paper making dryer canvas. A method for imparting antistatic properties to a papermaking dryer canvas by needle punching a web is described.
[0004]
Japanese Utility Model Laid-Open No. 6-6496 discloses that a fiber web used as a surface layer constituting member of a paper making dryer canvas has the same quality as that of the fiber web and has a metal coating film on the surface. A method of imparting antistatic properties by mixing is described.
[0005]
Furthermore, the dryer canvas for paper making described in Japanese Utility Model Laid-Open No. 2-61999 is based on a woven fabric that has been subjected to antistatic measures using a part of a yarn mixed with a conductive substance, A material obtained by needle punching a fiber web on this base fabric is also used depending on the application.
[0006]
In JP-A-8-134789, in a fiber web 41 used in a papermaking dryer canvas 40 shown in FIG. 11, conductive fibers 52 containing carbon fine particles are added to nylon fibers 51 as shown in FIG. A method is described in which antistatic properties are imparted by mixing the two-component composite conductive composite fibers 50 and needle punching the fiber web 41 on a base fabric 42. In addition, as this conductive conjugate fiber 50, an example using Mega III (trade name) manufactured by Unitika Ltd. is cited.
[0007]
[Problems to be solved by the invention]
By the way, in the papermaking dryer canvas described in Japanese Utility Model Publication No. 50-8203, conductive fibers such as carbon fibers and metal fibers are mixed in the fiber web, so that it is blended as a main component of the fiber web. Since the physical properties of the synthetic fiber and the conductive fiber, for example, the flexibility, are significantly different, the surface properties equivalent to those of a paper-making dryer canvas formed only of a synthetic fiber fiber web on the surface side cannot be obtained. In many cases, spots and the like were generated.
[0008]
Also, in the paper making dryer canvas described in Japanese Utility Model Laid-Open No. 6-6496, a repeated bending load is applied at the dry part, so that the coating strength decreases with time, and the metal coating film peels from the fiber surface. There is a problem that it becomes easy to do.
[0009]
Further, in the paper making dryer canvas described in Japanese Utility Model Publication No. 2-61999, the electric potential is increased around the yarn mixed with the conductive substance, and fine dust tends to be intensively attached to this part. There is a drawback that the discharge phenomenon tends to occur. When the discharge phenomenon becomes intense, individual fibers constituting the fiber web may be melted by being heated, making it difficult to use the paper making dryer canvas for a long period of time.
[0010]
On the other hand, in the paper making dryer canvas 40 described in JP-A-8-134789, the carbon fine particle content in the conductive composite fiber 50 is small, so that the surface characteristics of the fiber web 41 in contact with the wet paper are conductive. It is maintained at a level substantially equal to that of a fiber web that does not contain any synthetic fiber. As a result, it is described that the deterioration of the surface characteristics of the paper making dryer canvas due to insufficient bending strength and wear resistance can be avoided, and it can be used for a long period of time and can sufficiently exhibit the antistatic effect. Has been.
[0011]
However, in the dryer canvas for papermaking, as shown in FIG. 12, the conductive fibers 52 containing conductive carbon fine particles are exposed on the entire surface of the conductive composite fiber 50. Depending on the conditions, it was impossible to prevent the carbon fine particles from being transferred to the wet paper.
[0012]
Further, in the case of a dryer canvas formed by needle punching a fiber web on a base fabric, if there are carbon fine particles on the surface during needle punching, the carbon fine particles tend to come out of the conductive composite fiber 50 by any means. Met. When trying to prevent the carbon fine particles from coming out, there is a problem that the efficiency of the work of performing needle punching is lowered. Thus, it has been practically difficult to prevent the transfer of the carbon fine particles to the wet paper. As a result, a dryer canvas using a conductive fiber having a structure in which a conductive substance is not exposed on the fiber surface has been required.
[0013]
On the other hand, in order to cope with the recent increase in the speed of paper machines, a wet paper breaker detection device and a non-contact type automatic guide device at the lengthwise end (ear portion) of a dryer canvas have been introduced. It is coming. Therefore, depending on the combination and use with each detection device, the color of the dryer canvas that is colored not only white but also black, red, green, and blue has been required. In the case of a dryer canvas formed by needle punching a fiber web on a base fabric, the base fabric and a normal fiber web are originally white, so that various colors can be obtained by dyeing.
[0014]
However, if the antistatic measures against static electricity are applied to the dryer canvas, the content described in Japanese Patent Application Laid-Open No. 8-134789 described above is that the composite fiber itself is black because the conductive composite fiber contains carbon fine particles. It is. Even if the normal fiber web is white, when black conductive composite fiber is blended with it, the product has white and black color irregularities.
[0015]
Therefore, it is not completely white as a canvas product, and it is difficult to dye it in vivid red, green, blue, etc. by a dyeing process. As a result, the wet paper breakage detection device and the dryer canvas described above are difficult to dye. There was a problem that it was not possible to cope with the introduction of a non-contact type automatic guide device at the end (ear part) in the length direction. Further, if the above-described white and black color irregularities are formed on the surface of the paper making dryer canvas, there is a problem that it is difficult to know whether or not the surface is contaminated. In order to solve this problem, a white product has been required as a paper making dryer canvas.
[0016]
[Means for Solving the Problems]
  As technical means for solving the above-mentioned problems, the present invention provides a paper-making dryer canvas obtained by needle-punching a fiber web to a base fabric, and a core-sheath composite comprising an acrylonitrile copolymer in the fiber web. Core with fiberonlyConductivity of 10^-3It is characterized by blending conductive acrylic fiber containing 15 to 70% by volume of a conductive material of S / cm or more.
[0017]
In the present invention, the blending ratio of the conductive fibers is preferably 3% by weight or more, and more preferably 5% by weight or more based on the total weight of the fiber web.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention are described in detail below.
[0019]
  In the paper making dryer canvas 1 of this embodiment, as shown in FIG. 1, a fiber web 3 is superposed on the paper contact surface side of a base fabric 2 woven in a double woven structure, and then needle punching with the base fabric 2 is performed. The base fabric 2 and the fiber web 3 are joined into an integral structure, and the core portion is formed of a core-sheath composite fiber made of an acrylonitrile copolymer in the fiber web 3.onlyConductivity of 10^-3The conductive acrylic fiber 10 of FIG. 2 containing 15 to 70% by volume of a conductive material of S / cm or more is blended.
[0020]
Here, the core-sheath composite fiber composed of the acrylonitrile-based copolymer described above is not particularly limited as long as it is an acrylic copolymer that is usually used for the production of acrylic fiber. Further, the acrylic polymer constituting the core component and the sheath component may have the same composition or different compositions.
[0021]
In this embodiment, the case of double weaving is described, but the present invention is not limited to this.
[0022]
The blending ratio of the conductive fibers 10 is 3% by weight or more, preferably 5% by weight or more with respect to the total weight of the fiber web 3 described above. When the blending ratio is less than 3% by weight, the specific resistance value of one dryer canvas for papermaking is not reduced and the antistatic effect is reduced, and it cannot be used depending on the application. Further, if it is 3% by weight or more, there is a sufficient antistatic effect, which is preferable. Furthermore, when it is used for an application where the antistatic effect is strictly required, 5% by weight or more is desirable.
[0023]
【Example】
  The present applicant has a structure in which the conductive material specifically blended in the fiber web 3 has a structure in which the conductive material is not exposed on the fiber surface, and can take measures to prevent static electricity and speed up the paper machine. A white system that can easily detect whether or not dirt has adhered to the surface can be introduced with the use of a wet paper breakage detection device and a non-contact automatic guide device at the end (ear) of the dryer canvas. did. As a result, a core-sheath composite fiber made of an acrylonitrile copolymer is used to form a core part.onlyConductivity of 10^-3“Super-Electel” [trade name] manufactured by Mitsubishi Rayon Co., Ltd. (hereinafter referred to as SE fiber), which is a conductive acrylic fiber 10 containing 15 to 70% by volume of a conductive material of S / cm or more can be used. It turns out that there is a possibility. As shown in FIG. 2, the SE fiber 10 has a core-sheath structure in which white conductive fine particles are blended with an acrylic polymer at a high rate and a layer 11 and an acrylic polymer layer 12 are subjected to special composite spinning.
[0024]
Therefore, in order to confirm whether or not the SE fiber 10 can be used in the papermaking dryer canvas 1, performance tests of a steam test and a dry heat test were performed.
[0025]
(1) Steam heat test
1.0 kg / cm²The steam heat test was conducted in a saturated steam atmosphere. The test results are shown in FIG. FIG. 3 represents steamability, with the vertical axis representing the strength retention rate (%) and the horizontal axis representing the number of treatment days (days). For comparison with (1) SE used in the present invention product, (2) Mega III [manufactured by Unitika Ltd .: trade name of conductive composite fiber], (3) T (polyester fiber), (4) N (nylon fiber) and (5) AC (acrylic fiber) were also tested in the same manner. From this test result, it was found that SE has a higher strength retention than T and is comparable to other fibers, and that it can be used satisfactorily as a papermaking dryer canvas.
[0026]
(2) Dry heat test
A dry heat test was performed in an atmosphere at 150 ° C. The test results are shown in FIG. FIG. 4 represents dry heat property with the vertical axis representing the strength retention (%) and the horizontal axis representing the number of treatment days (days). For comparison with (1) SE used in the present invention, (2) Mega III [trade name of conductive composite fiber manufactured by Unitika Ltd.], (3) T (polyester fiber), (4) N (nylon fiber) and (5) AC (acrylic fiber) were also tested in the same manner. From this test result, it was found that SE has a higher strength retention than Mega III and exhibits almost the same characteristics as AC, and can be used satisfactorily as a papermaking dryer canvas.
[0027]
As a result, it was found that the SE fiber 10 has sufficient performance as the fiber web 3 of the paper making dryer canvas 1.
[0028]
Next, the Example of this invention using this SE fiber 10 is explained in full detail below. In the paper making dryer canvas 1 (see FIG. 1) of the present invention described above, the fiber web 3 is superimposed on the paper contact surface side of the base fabric 2 woven in a double woven structure, and then needle punching is performed together with the base fabric 2. The base fabric 2 and the fiber web 3 are joined in an integrated structure. As shown in the table of FIG. 5, the base fabric 2 is a polyester monofilament (TM) having a diameter of 0.4 mm, and the weave density of the warp 4 is 83.9 to 84.0 pieces / 2.54 cm, and the weft density of the weft 5 is It is manufactured by weaving into a double woven structure at 15.3 to 15.4 × 2 / 2.54 cm. Further, the fiber web 3 is produced by changing the blending ratio as shown in the same table of FIG.
[Example 1]
The fiber web 3 is composed of 55% by weight of 10 denier nylon fiber (N), 40% by weight of 10 denier acrylic fiber (AC), 5% by weight of 3 denier SE fiber 10 and a lamination amount of 300 g / m²A paper making dryer canvas 1 was produced.
[Example 2]
Fiber web 3 contains 10 denier nylon fiber (N) at 57% by weight, 10 denier acrylic fiber (AC) at 40% by weight, and 3 denier SE fiber 10 at 3% by weight. m²A paper making dryer canvas 1 was produced.
[Example 3]
The fiber web 3 is composed of 59% by weight of 10 denier nylon fiber (N), 40% by weight of acrylic fiber (AC) of 10 denier, 1% by weight of SE fiber 10 of 3 denier, and a lamination amount of 300 g / m²A paper making dryer canvas 1 was produced.
[0029]
In the above-described Examples 1 to 3, the SE fibers 10 blended in the fiber web 3 are changed to 5% by weight, 3% by weight, and 1% by weight, respectively. The specifications of each example are as shown in the list of FIG.
[0030]
Next, in order to compare the product of the present invention with the conventional product, a comparative example described in detail below was produced. Each comparative example is the same as the example (see FIG. 1), and after the fiber web 3 is superimposed on the paper contact surface side of the base fabric 2 woven into a double woven structure, needle punching is performed together with the base fabric 2 As a result, the base fabric 2 and the fiber web 3 are joined in an integral structure. The base fabric 2 of this comparative example has a polyester monofilament (TM) having a diameter of 0.4 mm as shown in the table of FIG. 6 and a weft density of warp yarns of 84.4 / 2.54 cm and a weave density of weft yarns of 5. It is manufactured by weaving into a double woven structure at 15.3-15.6 × 2 / 2.54 cm. In addition, the fiber web 3 is manufactured by changing the material and the mixing ratio as shown in the table of FIG.
[Comparative Example 1]
The fiber web 3 is made of 55% by weight of 10 denier nylon fiber (N), 40% by weight of 10 denier acrylic fiber (AC), 2.5 denier Mega III [made by Unitika Ltd.] Trade name of conductive conjugate fiber] is blended at 5% by weight, and the amount of lamination is 300 g / m.²A paper making dryer canvas 1 was produced.
[Comparative Example 2]
Fiber web 3 contains 10 denier nylon fiber (N) at 50% by weight, 10 denier acrylic fiber (AC) at 40% by weight, and conductive denier 2.5 denier Mega III at 10% by weight. , Stacking amount is 300g / m²A paper making dryer canvas 1 was produced.
[Comparative Example 3]
The fiber web 3 contains 10 denier nylon fiber (N) at 60% by weight, 10 denier acrylic fiber (AC) at 40% by weight, and a lamination amount of 300 g / m.²A paper making dryer canvas 1 was produced.
[0031]
In Comparative Examples 1 and 2, Mega III blended in the fiber web 3 is changed to 5 wt% and 10 wt%, respectively, and Comparative Example 3 shows a case where no conductive fiber is blended. . The specifications of each comparative example are as shown in the list of FIG.
[0032]
In order to evaluate the antistatic performance of the papermaking dryer canvas 1 manufactured as each example and comparative example described above, the resistance value measuring device of FIG. 7 is prepared, and the papermaking dryer canvas 1 described above is provided between the electrodes 21 and 22. The sample 25 is sandwiched and a predetermined current is supplied between the electrodes 21 and 22, and a super insulation meter 26 [SM-5E type manufactured by Toa Denpa Kogyo Co., Ltd.] is used to determine the resistance and specific resistance (volume specific) Resistance value) was measured. Each sample 25 was 10 cm long and 5 cm wide. The ambient conditions during the measurement were a temperature of 22.5 ° C. and a humidity of 57%.
[0033]
The measurement results for each example and comparative example are collectively shown in the list of FIG. From this measurement result, Example 1 shows substantially the same specific resistance value as Comparative Example 1 and Comparative Example 2, which is 10 more than Comparative Example 3 (when no conductive fiber is blended).²It can be seen that the order is small. Comparative Example 1 and Comparative Example 2 were mixed with 5% by weight and 10% by weight of the conductive fiber Mega III, respectively, and it was found that the antistatic effect was sufficient as the papermaking dryer canvas 1 with this composition. ing.
[0034]
Therefore, it can be seen that Example 1 has a sufficient antistatic effect. In addition, the specific resistance value of Example 2 and Example 3 is larger than that of Example 1. However, compared with Comparative Example 3, it is about 1/50 in Example 2 and about 1/10 in Example 3, and it can be used depending on the application in which the antistatic effect of the papermaking dryer canvas 1 is not strictly required. .
[0035]
Next, in order to evaluate the antistatic performance during use of the papermaking dryer canvas 1, a sample 30 of the papermaking dryer canvas 1 having a width of 15 cm and a length of 360 cm was prepared for each of the examples and the comparative examples. The traveling speed V is set to 100 m / min. With a tension of 1.0 kg / cm applied. 200 m / min. 300 m / min. The maximum voltage KV was measured when 5 minutes, 10 minutes, and 15 minutes had elapsed from the start of the test for each traveling speed.
[0036]
In the running test machine 31 shown in FIG. 9, a weight W and a pressure roller 32 are provided as means for adjusting the tension applied to the sample 30, and the charged voltage is measured above the running area of the sample 30. A container 33 [manufactured by Sicid Electrostatic Co., Ltd., trade name “Statilon-M”] is provided. In addition, a voltage sensor 34 is connected to the charged voltage measuring device 33 that is in the relationship of the relative arrangement position with the sample 30 while maintaining a spacing of 5 cm from the upper surface of the sample 30.
[0037]
The measurement results for each example and comparative example are shown in FIG. From this measurement result, with respect to the charged voltage of each sample, Example 1 and Example 2 are at substantially the same level as Comparative Example 1 and Comparative Example 2, and are much larger than Comparative Example 3 (when no conductive fiber is blended). It can be seen that the antistatic effect is sufficient. In Example 3, since the charged voltage is reduced by almost half as compared with Comparative Example 3, it cannot be used for a normal application, but can also be used for an application in which the antistatic effect is not strictly required. .
[0038]
From the measurement results of each test shown in FIGS. 8 and 10, it was found that if the SE fiber 10 is blended in the fiber web 3, there is an antistatic effect. As for the blending ratio of the SE fiber 10 to the fiber web 3, it can be seen from the measurement results that 3% by weight or more, preferably 5% by weight or more is very effective as an antistatic effect. Moreover, if it is less than 3 weight% and it is 1 weight% or more, it can also be used if it is a use which does not require the antistatic effect severely.
[0039]
About each Example, it was also confirmed that there was no color unevenness on the surface of the papermaking dryer canvas 1 by mixing SE fibers 10. In addition, in the Example, the fiber web 3 which mix | blended SE fiber 10 is piled up only on the paper contact surface side of the base fabric 2 in the papermaking dryer canvas 1 (refer FIG. 1). It is also possible to overlap the fiber web 3 on the upper and lower surfaces.
[0040]
Moreover, about the papermaking dryer canvas 1 of each Example, the confirmation test about whether an electroconductive fine particle was exposed to the surface was done. As a result, it was found that the phenomenon described above did not occur. This is because the SE fiber 10 has a core-sheath structure containing a conductive substance inside the fiber. Accordingly, it has been found that even when the papermaking dryer canvas 1 of the present invention is used, the phenomenon that the conductive substance is transferred to the wet paper does not occur.
[0041]
Furthermore, the needle punching operation in the production of the paper making dryer canvas 1 does not require special consideration just because the SE fiber 10 is used, and the work efficiency is lowered because it can be performed in the same manner as a normal fiber web. Work became possible without.
[0042]
Next, the dyeing processability of the papermaking dryer canvas 1 was confirmed for each example. As a result, it was confirmed that the dryer canvas 1 for papermaking with clear colors can be obtained by dyeing various colors such as black, red, green and blue. This is because the SE fiber 10 is white and can be clearly colored by a general dyeing process. As a result, a product that can cope with the introduction of a wet paper breakage detection device, a non-contact automatic guide device at the lengthwise end (ear portion) of the dryer canvas, and the like has been obtained.
[0043]
Further, since the SE fiber 10 is a fiber mainly composed of an acrylic polymer, and has excellent moisture and heat resistance, it is durable even in applications with a large steam load. Therefore, the SE fiber 10 that is a conductive fiber is used as the fiber web 3. Even if it is blended, the problem that the life of the papermaking dryer canvas 1 is not reduced does not occur, so that the papermaking dryer canvas 1 having durability and long life can be obtained.
[0044]
【The invention's effect】
According to the present invention, the SE fiber blended in the fiber web as the conductive fiber can provide a sufficient antistatic effect only by blending a small amount, so that the surface characteristics of the fiber web in contact with the wet paper is completely different from the conductive fiber. It is maintained at a level approximately equal to that of the non-containing fiber web. In addition, by disposing a relatively small amount of conductive fibers in the fiber web, an antistatic area is formed almost uniformly over the entire paper-contacting surface of the paper making dryer canvas. There is no inconvenience that dust is concentrated on this portion.
[0045]
In addition, if the papermaking dryer canvas of the present invention is used, the problem of transfer of conductive substances to wet paper can be solved, and needle punching work at the time of canvas production requires special consideration when using SE fibers. Therefore, work efficiency is not reduced. In addition, since it can be dyed into various colors, it is possible to provide a papermaking dryer canvas that has excellent dyeing processability, has a clear color, and can be used for applications requiring various color specifications.
[0046]
Furthermore, since SE fiber is white, white and black color unevenness does not occur on the surface of the canvas product. Therefore, even if there is dirt on the surface of the paper making dryer canvas, it has an easy-to-understand effect. . Thereby, it can be used also for the use for which a white papermaking dryer canvas is required. Further, since SE fiber is a fiber mainly composed of acrylic polymer, it has an effect of maintaining a long life of the paper making dryer canvas because of its excellent heat and heat resistance and durability even in a large steam load application.
[Brief description of the drawings]
[Figure 1] Sectional drawing which shows the organization structure of the dryer canvas for papermaking which concerns on this invention
[Figure 2] Sectional drawing which shows the structure of SE fiber mix | blended with the fiber web of FIG.
[Fig. 3] Characteristic diagram showing test results of steam test conducted in the present invention
[Fig. 4] Characteristic diagram showing test results of dry heat test conducted in the present invention
[Figure 5] List showing specifications of each embodiment of the present invention
[Fig. 6] List showing specifications of each comparative example for comparison with each example of the present invention
[Fig. 7] (A) is a schematic block diagram showing a resistance measurement device for evaluating the antistatic performance of a papermaking dryer canvas (b) is a cross-sectional view thereof
[Fig. 8] Table showing resistance value measurement results for each example and comparative example
FIG. 9 Schematic configuration diagram showing a running test machine for evaluating antistatic performance when using a papermaking dryer canvas
FIG. 10 Characteristic diagram showing the charged voltage measurement results for each example and comparative example
FIG. 11 Organizational structure diagram showing a conventional example of a dryer canvas for papermaking
FIG. FIG. 11 is a structural diagram showing conductive composite fibers mixed in the fiber web of FIG.
[Explanation of symbols]
  1 Dryer canvas for papermaking
  2 base fabric
3 Fiber web
10 Conductive fiber (SE fiber)

Claims (1)

In a dryer canvas for paper making, in which a fiber web is needle punched on a base fabric, a conductive material having a conductivity of 10 ⁻³ S / cm or more only in a core portion of a core-sheath composite fiber made of an acrylonitrile copolymer in the fiber web. A paper-making dryer canvas comprising a conductive acrylic fiber containing 15 to 70% by volume of a conductive substance.

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