JP2000170086A - Press felt for paper making - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce press felt for paper making that has excellent smoothness with minimized unevenness at the yarn-crossing points and retain high strength. SOLUTION: In the press felt for paper making comprising the base fabric B woven with the warp yarns S and the weft yarns U and the web to be laminated on the base fabric, the yarn material constituting the base fabric B is partially or wholly made of a composite fiber material 1 composed of a low melting material and a high-melting material in which the difference between their melting points is >=30 deg.C and they are constituted so that the unevenness may be reduced and smoothened at the yarn-crossing points K and the strength of the composite yarn material 1 may not be lowered on the weft yarn side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a papermaking press felt, and more particularly to a papermaking press felt having excellent smoothness.

[0002]

2. Description of the Related Art In a general papermaking process, paper is formed by removing water from a pulp fiber slurry.
As is well known, in the step of removing the water, a papermaking press felt including a base fabric woven by a warp yarn and a driven yarn and a web laminated and entangled with the base fabric is used. .

The papermaking press felt is required to have a function as a filter for removing moisture from the pulp fiber slurry and a function as a conveyor for transferring the pulp fiber slurry. That is, the paper to be manufactured undergoes a papermaking process in a state of being placed on the felt, so that the surface shape of the felt is reflected on the surface of the paper. Therefore, a press felt for papermaking is required to have surface smoothness.

[0004] The surface smoothness depends on the structure of a woven fabric serving as a base fabric of a press felt for papermaking. That is, in the base fabric woven from the warp yarn and the driven yarn, entangled points between the yarn materials are formed, and the ups and downs of the yarn at the entangled points directly generate irregularities on the surface of the felt.

FIG. 10 is an enlarged sectional view of a base fabric of a conventional press felt for papermaking. The base fabric B is warped by the loom S
And the driving yarn U to form an interlacing point K. The entanglement point K is a state where the warping yarn S is in contact with either the upper or lower side of the driving yarn U. Here, for example, the vertex U ₁ ′ of _one of the driving yarns U ₁ out of the adjacent driving yarns U ₁ and U _2.
When the distance D ₁ between the vertex S ₁ integer warp S where the other implant thread U ₂ is pushed up, but also the other driving yarn U
_A distance D ₂ is generated between the lowest point U ₂ ′ of _{No. 2} and the lowest point S ₂ of the warp yarn S on which _one driving yarn U ₁ is pushed down.

Due to the distances D ₁ and D ₂ , countless irregularities are formed on the front and back surfaces of the base fabric B, and these irregularities impair the smoothness of the papermaking press felt. In particular, in recent years, the use of a thread material such as a hard monofilament has become mainstream, and the smoothness has tended to be further impaired.

Accordingly, the applicant of the present application has previously disclosed a papermaking press felt having excellent smoothness (Japanese Utility Model Application No. 60-140130).
No. <Utility Model Registration No. 1837061>).
This technical content is shown in FIGS.

[0008] The thread material a shown in FIG. Further, the thread material b shown in FIG. 12 has a core-sheath structure, in which the core is composed of a high melting point material 3 and the sheath is composed of a low melting point material 2. As shown in FIG. 13, as shown in FIG.
70 °) and heat set, the yarns a, b
The softening of the low-melting-point material 2 causes the entanglement points K of the warping yarn S and the driving yarn U to bite and mesh with each other as shown in FIG.

That is, as shown in FIG. 14, when the entanglement points K penetrate each other, the unevenness at the entanglement point K is smaller than that in the case of FIG. Become.

[0010]

However, in the technique disclosed in Japanese Utility Model Application No. 60-140130, one of the yarns a to be woven is made of the low melting point material 2 and the other yarn b is sheathed. Is a core-sheath structure composed of the low melting point material 2, and it cannot be said that there is no possibility that the strength is significantly reduced by heat and tension during heat setting.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a papermaking press felt which has a small unevenness at an interlacing point, can ensure smoothness, and maintains high strength. To provide.

[0012]

Means for Solving the Problems In order to achieve the above object, a papermaking press felt according to the present invention is laminated with a base fabric woven by warping yarns and driven yarns and laminated on the base fabric. In papermaking press felt consisting of web and
All or a part of at least one of the yarn materials constituting the base fabric is a composite yarn material of a low-melting material and a high-melting material having a melting point difference of 30 ° C. or more, and at the time of heat setting The unevenness at the entangled point was reduced by heat and tension to maintain smoothness, and the strength of the thread material on the biting side was not reduced.

Further, in the papermaking press felt according to the second aspect of the present invention, when a composite yarn material is used as a part of at least one of the yarn materials constituting the base fabric, the composite yarn material is not used. The composition ratio with the composite yarn material is 1: 1 to 1: 3 or 1: 1 to 3: 1. The composite yarn material does not bite at the interlacing point due to heat and tension during heat setting. It was configured to maintain smoothness even when mixed with non-composite yarn material.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, based on FIGS.
An embodiment of the present invention will be described. 1 is an enlarged cross-sectional view of a composite yarn material, FIG. 2 is an enlarged perspective view showing a portion of an interlace point of a base fabric, FIG. 3 is an enlarged cross-sectional view of another composite yarn material, and FIGS. FIG. 9 is a perspective view schematically showing the used base fabric, and FIG. 9 is a view showing the static physical properties of the papermaking press felt according to the present invention.

The composite thread material 1 shown in FIG. 1 has a core-sheath structure in which a high melting point material 3 is used as a core and a low melting point material 2 is used as a sheath. The difference between the melting points of the low melting point material 2 and the high melting point material 3 is at least 30 ° C. or more, preferably 50 ° C. to 7 ° C. by the DSC method.
Desirably, there is a melting point difference of 0 ° C.

The composite yarn material 1 is prepared by selecting and combining any of nylon 12, nylon 1212, nylon 12 elastomer, copolymer nylon, nylon 6, nylon 66, nylon 610, nylon 612, and semi-aromatic polyamide. It is composed.

The composite yarn material 1 is used as one or both of a warping yarn S and a driving yarn U when weaving a base fabric of a papermaking press felt, and is entangled after heat setting in which tension and heat are applied. At the point K, the warp yarn S side using the composite yarn material 1 becomes the cut-in side yarn material as shown in FIG. 2 and flattens at the interlacing point K, resulting in a papermaking press felt with reduced unevenness and good smoothness.

The difference between the melting points of the low-melting material 2 and the high-melting material 3 constituting the composite yarn material 1 is required to be 30 ° C. or more by the DSC method. This is because conditions that do not greatly affect the physical characteristics of the high melting point material 3 can be set while softening or melting the material 2.

The combination of the low-melting material 2 and the high-melting material 3 of the composite yarn 1 is not limited to the core-sheath structure shown in FIG. For example, as shown in FIG. 3, a split yarn material having a so-called sea-island composite structure may be used. In this case, the sea component is composed of the low melting point material 2, and the island component is composed of the high melting point material 3.

Although not shown, the composite yarn material 1 may have a structure in which a low-melting material 2 and a high-melting material 3 are combined in parallel, or an eccentric core-sheath structure. Of course.

When the composite yarn 1 is used as a part of at least one of the yarns constituting the base fabric B of the papermaking press felt to be realized, the composite yarn 1 and the non-composite yarn ( General thread material that is not easily softened or melted by heat) 4
Is preferably in the range of 1: 1 to 1: 3, or 1: 1 to 3: 1. If it is within this range, unevenness is eliminated at the point of confounding between the composite yarn material 1 and the non-composite yarn material 4 due to heat and tension at the time of heat setting. However, smoothness is generally ensured.

FIGS. 4 to 8 show typical examples of the above composition ratios. FIG. 4 shows a composite yarn material (dotted pattern) 1 on all warp yarns S.
Non-composite thread material (no pattern) 4
Is used. In this case, the heat and tension during heat setting cause the composite yarn material 1 side to bite at all of the confounding points K with the non-composite yarn material 4, so that there is no unevenness and sufficient smoothness is secured.

Next, FIG. 5 shows a warp yarn S in which a composite yarn material (dotted pattern) 1 and a non-composite yarn material (non-pattern) 4 are arranged in a 1: 1 composition ratio. 6 shows a case where the non-composite yarn (non-pattern) 4 is used, and FIG. 6 shows that the warp yarn S is composed of the composite yarn (dotted pattern) 1 and the non-composite yarn (non-pattern) 4 in a ratio of 1: 2 7 shows a case where the non-composite yarn material (non-pattern) 4 is used for all the driving yarns U, and FIG. 7 shows the warp yarn S as the composite yarn material (dotted pattern) 1 and the non-composite yarn material. (No pattern) 4
Are arranged in a composition ratio of 1: 3, and all of the driving yarns U are made of the non-composite yarn material (patternless) 4.

FIG. 8 shows a case where the composite yarn material (dotted pattern) 1 is used for all the driving yarns U and the non-composite yarn material (no pattern) 4 is used for all the warp yarns S. In this case, the usage of the composite yarn material 1 and the non-composite yarn material 4 is reversed from that of FIG. It goes without saying that there is no unevenness due to the bite at all the confounding points, so that sufficient smoothness can be ensured.

As for the use of the composite yarn 1 and the non-composite yarn 4, a better effect can be obtained when the composite yarn 1 is used as a warp yarn than when it is used as a driving yarn. That is, in a woven fabric, a warp yarn has a property of forming a so-called knuckle due to a large rise and fall at a point of intertwining with a driven yarn. That is, when the composite yarn material 1 is used as the warp yarn, it is effective to reduce the knuckle.

In view of the dimensional stability and strength of the papermaking press felt, it is more preferable to use the composite yarn material 1 for warping yarn. This is because more crimps are formed by the warp yarn as a woven fabric, and it is preferable to flatten the crimp sharpness.

[0027]

Embodiment 1 A composite yarn material 1 composed of a monofilament twisted yarn of a core-sheath composite fiber having a core of nylon 6 (melting point 220 ° C.) and a sheath of copolymer nylon (melting point 190 ° C.), and a non-composite made of nylon 6 An endless bag-shaped base fabric B was obtained by weaving with the thread material 4.

The base fabric B uses a part of one of the warp yarn and the driving yarn as the composite yarn material 1, and the composite yarn material 1 and the non-composite yarn material 4 are 1: 1 to 1: 3; Alternatively, the composition ratio is set to 1: 1 to 3: 1.

Then, after the base fabric is treated in a heat setting process at 160 ° C., needle punching is performed while successively laminating short fiber webs until the web basis weight becomes 400 g / m ^2. Then, it was wrapped between a pair of rolls and hot-pressed again under a tension of 10 kg / cm to obtain a papermaking press felt.

[0030]

Embodiment 2 The sea component is nylon 612 (melting point 210 °)
C) An endless bag-shaped base fabric formed by weaving a composite yarn 1 made of a monofilament twisted sea-island composite fiber having an island component of nylon 66 (melting point 260 ° C.) and a non-composite yarn 4 made of nylon 6. I got

The base fabric uses a warp yarn or a part of a driven yarn as the composite yarn material 1, and the composite yarn material 1 and the non-composite yarn material 4 are 1: 1 to 1: 3 or 1: 1. 1 to 3: 1.

Then, after the base fabric is treated by heat setting at 180 ° C., needle punching is performed while continuously laminating short fiber webs until the web basis weight becomes 400 g / m ^2. Then, it was wrapped between a pair of rolls and hot-pressed again under a tension of 10 kg / cm to obtain a papermaking press felt.

9 (a) and 9 (b) show the static physical properties of the papermaking press felts obtained in Examples 1 and 2 above. In the figure, the `` paper smoothness index '' is the reciprocal of a numerical value obtained from the dispersion of the distance between adjacent peaks and valleys of the surface unevenness of the papermaking press felt, and the larger the numerical value, the smaller the unevenness of the unevenness distance. , Indicates that the smoothness is high. The “strength” is defined as the cutting strength of a papermaking press felt using a base cloth made of nylon 6 alone as 100.

The felt of Example 1 shown in FIG. 9A and the felt of Example 2 shown in FIG. 9B each have excellent surface smoothness on paper and have sufficient strength. You can see that.

The felt of the first embodiment shown in FIG.
As compared with the felt of Example 2 shown in FIG. 2B, the surface smoothness on paper is more excellent, and conversely, the felt of Example 2 is more excellent in strength than the felt of Example 1. Can be confirmed.

In order to further optimize the properties in terms of surface smoothness and strength, the selection of the fibers of the composite yarn and the selection of the fibers of the non-composite yarn are, of course, left. And the invention is not limited to the above embodiment.

[0037]

As described above, the papermaking press felt according to the present invention is a papermaking press felt comprising a base fabric woven by warping yarns and driven yarns and a web laminated on the base fabric. Since all or a part of at least one of the yarn materials constituting the base fabric is a composite yarn material of a low-melting material and a high-melting material having a melting point difference of 30 ° C. or more, Excellent in smoothness because the composite yarn material cuts into the confounding point due to heat and tension during setting to reduce unevenness, and the composite yarn material containing high melting point material decreases in strength due to heat and tension during heat setting It has various excellent effects such as no effect.

Further, in the papermaking press felt according to the second aspect of the present invention, when a composite yarn material is used as a part of at least one of the yarn materials constituting the base fabric, the composite yarn material is not used. Since the composition ratio with the composite yarn material is 1: 1 to 1: 3 or 1: 1 to 3: 1, irregularities are formed at a portion where the composite yarn material is entangled by heat and tension during heat setting. Thus, an excellent effect of being excellent in smoothness and having sufficient strength is exhibited.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a composite yarn material.

FIG. 2 is an enlarged perspective view showing a portion of a confounding point of the base cloth.

FIG. 3 is an enlarged sectional view of another composite yarn material.

FIG. 4 is a perspective view schematically showing a base fabric using a composite yarn material for all warp yarns and a non-composite yarn material for all driving yarns.

FIG. 5 is a perspective view schematically showing a base fabric in which a composite yarn material and a non-composite yarn material are used in a warp yarn at a composition ratio of 1: 1.

FIG. 6 is a perspective view schematically showing a base fabric in which a composite yarn material and a non-composite yarn material are used in a warping yarn at a composition ratio of 1: 2.

FIG. 7 is a perspective view schematically showing a base fabric in which a composite yarn material and a non-composite yarn material are used in a warping yarn in a composition ratio of 1: 3.

FIG. 8 is a perspective view schematically showing a base fabric using a composite yarn material for all driving yarns and a non-composite yarn material for all warp yarns.

9A and 9B are diagrams showing static physical properties of a papermaking press felt according to the present invention, wherein FIG. 9A is that of Example 1 and FIG. 9B is that of Example 2.

FIG. 10 is an enlarged sectional view showing a base fabric of a conventional press felt for papermaking.

FIG. 11 is an enlarged cross-sectional view of a yarn material used as a warping yarn or a driving yarn constituting a base fabric of a conventional press felt for papermaking.

FIG. 12 is an enlarged cross-sectional view of a yarn material having a core-sheath structure used as a warp yarn or a driving yarn constituting a base fabric of a conventional papermaking press felt.

FIG. 13 is a perspective view of a base fabric of a conventional papermaking press felt.

FIG. 14 is a perspective view of a tangling point with a warping yarn or a driving yarn constituting a base fabric of a conventional papermaking press felt.

[Explanation of symbols]

Reference Signs List 1 composite yarn material 2 low melting point material, 3 high melting point material, 4 non-composite yarn material (general yarn material) B base cloth S warping yarn S ₁ vertex of warping yarn S ₂ lowest point of warping yarn U, U ₁ , U ₂ Driving yarn U ₁ ′ Apex of driving yarn U ₂ ′ Lowermost point of driving yarn D ₁ , D ₂ Distance a, b Thread material

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hirofumi Murakami 430-9 Nendo, Kashiwa-shi, Chiba No.205 No. 205, Kaori Kita-Kashiwa, Ichikawa F-term (reference) 4L055 CE39 EA20 EA32 FA14

Claims (2)

[Claims] 1. A papermaking press felt comprising a base fabric woven by a warping yarn and a driving yarn, and a web laminated and entangled with the base fabric, wherein at least one yarn material constituting the base fabric Characterized in that all or a part of the composite felt is a composite thread material of a low melting point material and a high melting point material having a melting point difference of 30 ° C. or more. 2. When a composite yarn is used as a part of at least one of the yarns constituting the base fabric, the composition ratio of the composite yarn to the non-composite yarn is 1: 1 to 1: 3. 2. The papermaking press felt according to claim 1, wherein the ratio is 1: 1 to 3: 1.