JP3497638B2 - Dryer canvas for papermaking - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking dryer canvas which has abrasion resistance, wet heat resistance and excellent durability.

[0002]

2. Description of the Related Art A papermaking dryer canvas is generally made of a polyester monofilament excellent in abrasion resistance, high tensile strength and chemical resistance.
However, polyester monofilaments are not necessarily excellent in durability as a papermaking dryer canvas because they undergo fibrillation when subjected to high tension under high humidity and heat, and the strength decreases over time.

On the other hand, since the polyolefin monofilament does not deteriorate in strength even under high humidity and heat up to about 120 ° C., a papermaking dryer canvas made of, for example, polypropylene monofilament is practically used as a canvas having excellent durability. There is.

However, compared with polyester monofilaments, polypropylene monofilaments have a problem that they are not sufficient in abrasion resistance and dimensional stability under high tension.

Therefore, various proposals have been made to supplement the above-mentioned disadvantages of the polyester monofilament and the polypropylene monofilament. For example, Jikkou 57-355
No. 99 is a canvas for papermaking mainly composed of polypropylene monofilaments, in which a polyester filament coated with polypropylene or a fluororesin is incorporated as a straight warp to supplement the dimensional stability.

In this canvas for papermaking, the warp yarn and the weft yarn are both composed of polypropylene monofilament, so that they are excellent in chemical resistance and resistance to moisture and heat deterioration, and are composed of polyester filaments in which orthogonal warp yarns are coated with polypropylene or a fluororesin. Therefore, the dimensional stability is also improved. However, the problem of poor abrasion resistance has not been solved because it is mainly composed of polypropylene monofilaments.

[0007] Japanese Patent Publication No. 59-11719 discloses that a canvas for papermaking is composed of polyester filaments of polytetramethylene terephthalate or polyhexamethylene terephthalate (both multifilament and monofilament are possible). It is intended to make up for the disadvantages.

However, it has been found that although the canvas for papermaking has some improvement in hardness and rigidity, it cannot be expected to have a significant improvement in wet heat resistance. An object of the present invention is to realize a papermaking dryer canvas that satisfies all of abrasion resistance, wet heat resistance, and durability.

[0009]

[Means for Solving the Problems] Since the paper contacting surface side hits the paper, the abrasion resistance is required to be stronger than that on the non-contacting paper surface side, and
While dimensional stability is required to prevent the paper from being deformed, there is a circumstance in which the paper contact side directly contacts the dryer cylinder, so that the moist heat resistance is strongly required than the paper contact side.

Therefore, in the present invention, a polyester monofilament having high abrasion resistance and high dimensional stability is used for the surface layer warp on the paper contact side, and a polypropylene monofilament having excellent wet heat resistance is used for the back layer warp on the opposite paper side. The said subject was solved. Further, the twill weave was used as the surface layer structure to improve the wear resistance. Furthermore, by setting the density of the back layer warp to 1/8 to 2/3 that of the surface layer warp, both durability and dimensional stability are ideally made compatible.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the dryer canvas having the structure shown in FIG. 1, a polyester monofilament is used for the surface layer warp 11 on the paper contact side (hereinafter referred to as PS side), and the non-paper contact side (hereinafter referred to as BS side) back. Polypropylene monofilament was used for the layer warp 12.

Since the high wear resistance and dimensional stability of the polyester monofilament and the excellent wet heat resistance of the polypropylene monofilament are utilized in the parts where it is most needed, the canvas as a whole has both wear resistance and wet heat resistance, and A papermaking dryer canvas 1 having excellent durability can be obtained.

Here, the diameter of the polyester monofilament yarn used for the PS side warp 11 is 0.3 mm to 0.6 m.
The range of m is preferable, and if it is smaller than 0.3 mm, the abrasion resistance is lowered, and if it is larger than 0.6 mm, the smoothness of the surface is impaired, so 0.4 to 0.5 mm is more preferable.

The density of the PS side warp 11 is 50 to 90 yarns /
The range of 2.54 cm is preferable, 50 lines / 2.54 cm
If it is less than 50, strength retention and dimensional stability will be insufficient, and if it is more than 90 pieces / 2.54 cm, the air permeability will be impaired, so 55 to 85 pieces / 2.54 cm is more preferable.

The diameter of the polypropylene monofilament used for the BS side warp 12 is preferably in the range of 0.3 mm to 0.6 mm. If it is smaller than 0.3 mm, the dimensional stability becomes low, and if it is larger than 0.6 mm, it is used as a dryer canvas. Since the flexibility is impaired, 0.4 mm to 0.6 m
m is more preferred.

The density of the BS side warp 12 is equal to that of the PS side warp 11.
The density is preferably 1/8 to 2/3. This is because if it is 1/8 or less, the durability as a dryer canvas becomes poor, and if it is 2/3 or more, the dimensional stability as a dryer canvas is impaired, and 1/6 to 1/2 is more preferable.

Further, it is desirable that the design of the BS side warp 12 is, for example, a 3/1 twill weave as shown in FIG. 1 in order to improve abrasion resistance. This is because, generally, when a twill weave is used, the area of paper contact increases and the surface pressure of paper contact decreases.

In FIG. 1, 21 is a surface side weft, 2
2 is a middle layer weft, and 23 is a back layer side weft. There are no particular restrictions on the type of yarn used for these wefts 21-23. Various weft yarns used in papermaking dryer canvas can be used.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be specifically described with reference to the drawings by embodiments. In this example, the dryer canvas 10 was woven with the structure shown in FIG.

The PS side warp 31 is a 3/1 twill weft triple weave, and the PS side warp 31 is a polyester monofilament yarn having a diameter of 0.46 mm for 5 to 12 of the warp numbers 1 to 12 shown in FIG. , Its density is 58.0 / 2.54
cm. The BS side warp 32 has warp numbers 1 to 1 shown in FIG.
Polypropylene monofilament yarns having a diameter of 0.5 mm were used for 12 to 12, and the density thereof was set to 29.0 threads / 2.54 cm, which is 1/2 of the density of the PS side warp 31.

On the other hand, the PS side weft 41 and the BS side weft 43
Is a polyester monofilament yarn having a diameter of 0.55 mm, and the middle layer weft yarn 42 is an acrylic spun yarn in which four 6th yarns are twisted. Weft density is PS side weft 4
1, BS side weft yarn 43 and middle layer weft yarn 42 were both 16.0
Book / 2.54 cm was woven. After weaving, the dryer canvas 10 was heat set. The obtained product had an air permeability of 3,800 cc / min / cm ² and a thickness of 2.9 mm. The design of the PS side warp 31 was a 3/1 twill weave as a test as shown in this Example, but it was found that the abrasion resistance was more than expected. In this embodiment, the 3/1 twill weave is used. However, the present invention is not limited to this and other twill weaves such as 2/1 and 4/1 also have the same effect of improving the wear resistance.

[0022]

According to the present invention, the polyester monofilament yarn is used as the surface layer warp on the paper contact side and the polypropylene monofilament yarn is used as the back layer warp on the opposite paper side. Therefore, the polyester monofilament yarn of the surface layer warp is used. Abrasion resistance, dimensional stability, and durability are shared by the back layer, and the polypropylene monofilament yarn of the back layer warps wet heat resistance, so the canvas as a whole has excellent abrasion resistance, dimensional stability, durability, and moist heat resistance. A dryer canvas for use is obtained, and when the surface layer structure is a twill weave, an increase in the paper contact area,
The paper contact pressure is reduced, wear resistance is further improved, dimensional stability is obtained by reducing the wear amount, and the wet heat resistance, which is an advantage of polypropylene monofilament yarn, is also obtained.As a result, the durability is further improved. An excellent dryer canvas is obtained. Further, by setting the density of the back layer warp to 1/8 to 2/3 of the density of the front layer warp, it is possible to ideally achieve both dimensional stability and durability.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a papermaking dryer canvas according to the present invention.

FIG. 2 is a weaving diagram of a dryer canvas for papermaking according to the present invention.

[Explanation of symbols]

1,10 Paper making dryer canvas 11,31 Surface layer warp 12,32 Back layer warp 21-23 Weft 41-43 weft

Claims (3)

(57) [Claims] 1. A dryer canvas for papermaking woven using monofilament yarns as warp yarns, wherein polyester monofilament yarns are used as surface layer warp yarns on the paper-contacting surface side and polypropylene monofilament yarns are used as back layer warp yarns on the opposite paper-contacting surface side. A papermaking dryer canvas that is characterized by the fact that it was used. 2. The paper-making dryer canvas according to claim 1, wherein the surface layer structure is a twill weave. 3. The paper-making dryer canvas according to claim 1 or 2, wherein the back layer warp has a density of ⅛ to 2/3 of the surface layer warp density.