JPH05321186A - Felt for making paper and its production - Google Patents

Abstract

PURPOSE:To provide the felt holding good water permeability without causing a depilation phenomenon, enhanced in surface smoothness by the formation of the dense surface, and used for the production of paper, and to provide the method for producing the same. CONSTITUTION:The felt for the production of paper comprises a base layer 1 and a surface layer 2 formed on at least one surface of the base layer, and the base layer 1 and the surface layer 2 are incorporated by needling. The surface layer 2 contains dividing fine fibers divided by the needling and non- dividing fibers, and before divided into the divided fibers the dividing fibers are compounded with the non-dividing fibers in a ratio of 40-90wt.% based on the total amount of the dividing fibers and the non-dividing fibers. The base layer 1 comprises a base cloth 11 and ordinary pad fiber layers 12, 13 placed on the upper and lower surfaces. Each of the dividing fibers has a circular cross section and a fineness of 4-20 deniers. The cross-sectional shape of a material composing of the dividing fiber is an eight petal type, and the cross- sectional shape of the other material is a fan type divided into eight fans. The thickness of the surface layer is 0.35-1.2mm, and the air permeability is 10-30cm<3>/ sec/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking felt used in a paper machine and a method for producing the same, and more particularly to a papermaking felt used for producing high-quality paper and the like and a method for producing the same.

[0002]

2. Description of the Related Art A felt for papermaking is required to have a function as a conveyer for carrying wet paper to squeeze water from the wet paper and at the same time smooth the surface of the wet paper. In particular, high-quality paper, thin paper, etc. are required to have a felt surface with no unevenness in order to exert their characteristics, and in the past, fine fibers have been used for papermaking felt in order to make a dense and smooth felt. There was a request.

[0003]

However, when thin fibers are used, they have a defect that they adhere to the cylinder during the carding process and become a film form that does not separate well. In the needling process, too, the needle diameter and the fiber thickness are too wide, which causes a problem that a large wave is struck and the needle is not smooth. Even if the above-mentioned drawbacks are eliminated and a felt for papermaking is made of ultrafine fibers, there is a new problem that the ultrafine fibers are easily broken and a hair loss phenomenon occurs. Furthermore, as the fibers become thinner, the surface of the papermaking felt becomes more dense and the smoothness is maintained, but on the contrary, the water permeability decreases, and water must be squeezed out from the wet paper as much as possible. The important function of the papermaking felt, which is not achieved, will be lost.

The present invention overcomes the above problems.
An object of the present invention is to provide a felt for papermaking in which smoothness is enhanced by forming a dense surface without causing hair loss phenomenon while maintaining water permeability, and a manufacturing method thereof.

[0005]

The papermaking felt of the first invention comprises a base layer and a surface layer formed on at least one surface of the base layer. The base layer and the surface layer are formed by needling. The surface layer includes the divided fine fibers and the non-divided fibers divided by needling, and the mixing ratio of the dividing fibers before being divided into the divided fine fibers is the dividing fibers. And for the non-split fibers,
It is characterized by being 40 to 90% by weight (hereinafter, simply referred to as%).

Here, the "base layer" refers to a fiber layer composed of a base cloth and a normal pad fiber layer. The “division fiber” refers to a composite fiber having a structure in which it is divided into fine divided fine fibers by needling, and its component, property, cross-sectional shape, diameter, divided form and the like may be any. For example, as the splitting fibers, as shown in the second invention, the cross section is circular, the denier is 4 to 20, and the shape of one material is 8 petal type, and the other is 8 equally divided. It is possible to use a sectioned fan-shaped cross section. When the wire diameter is 4 to 20 denier, excellent effects as the papermaking felt according to the present invention can be obtained. That is, if the fiber diameter of the dividing fibers is too thick, it is difficult to divide by needling, and thin fibers cannot be obtained as dividing fine fibers. On the contrary, if the dividing fibers are too thin, the dividing fine fibers are easily broken, and hair is removed. It is easy to cause a phenomenon.

The compounding ratio of this dividing fiber is 40 to 90%.
The reason is that in the range of (3), excellent surface smoothness is obtained without lowering air permeability (water permeability). On the other hand, if it exceeds 90%, the amount of fine fibers becomes too large, and the fibers tend to stick to the cylinder of the card, making handling difficult. The “divided fine fiber” means a fiber whose diameter is reduced by mechanically peeling the dividing fiber by needling and dividing it into a plurality of pieces. "Undivided fiber" means
It refers to ordinary ordinary fibers that are not divided by needling.

In the papermaking felt of the present invention, the thickness of the surface layer is not particularly limited, but as in the third invention,
It is preferably 0.35 to 1.2 mm. 0.2 mm
If it is less than 1.2 mm, the degree of improvement in smoothness is small, and if it exceeds 1.2 mm, in-layer peeling of the fine fiber layer is likely to occur, and since it is dense, water permeability decreases. The air permeability of the papermaking felt of the present invention is 10 to 30 cm ³ / sec / cm ^2.
It is preferable that This ensures the drainage capacity of the water squeezed between the press rolls, and the water squeezed from the wet paper to the felt moves from the felt to the wet paper when the felt and the wet paper leave the press section. This is because it is suitable for suppressing the re-wetting phenomenon in which it reverts.

In the method for producing a felt for papermaking according to the fifth aspect of the present invention, at least one surface of the base material is divided into fibers 40 to 40 for dividing.
A split type pad fiber layer composed of 90% and non-split fibers constituting the balance is arranged, and thereafter, at least not only the split type pad fiber layer (I) but also the split type pad fiber layer and the base material. The present manufacturing method is characterized in that the splitting fibers are split by needling through the interface portion (II) so as to be overlapped, and the interface portion is joined by the fibers that are hooked on the barbs by the needling and move downward. In the method as well, various splitting fibers can be selected and used in the same manner as described above. For example, as shown in the sixth invention, the splitting fiber has a circular cross section with a denier of 4 to 20 and one material Can have an 8-petal type, and the other can have a cross-sectional fan type with 8 sections divided substantially equally.

[0010]

According to the papermaking felt and the method for producing the same according to the present invention, a split type pad fiber layer composed of splitting fibers and non-splitting fibers is arranged on a substrate, and the above substrate and split type are formed by needling. In the process of forming the base layer and the surface layer by intertwining and integrating the bad fiber layers, the splitting fibers are split and gradually become ultrafine split fine fibers. Therefore, since the felt surface becomes dense, there is no phenomenon that the felt surface is wavy due to the use of the ultrafine fibers from the beginning, and it is possible to obtain a smooth felt in which the surface is made dense and paper quality is improved. In addition, since the surface layer is thinly formed on the base layer having water permeability and water squeezing property, the moisture that has passed through this surface layer flows back to the paper sheet by the thin surface layer that is densely configured while ensuring water permeability. Rewetting can be prevented. Furthermore, since the splitting fine fibers cause the splitting fibers to be split by the needling and still leave a bundle-like cohesion, hair loss phenomenon and the like caused by using the ultrafine fibers from the beginning are unlikely to occur.

[0011]

EXAMPLES The present invention will be specifically described below with reference to examples. (1) Example 1 Method for manufacturing felt for papermaking First, a base cloth is entangled with and integrated with normal pad fiber layers above and below the base cloth. It takes the form of a conventional papermaking felt due to needling. As the base cloth, a warp yarn was twisted with two polyamide monofilaments having a diameter of 0.20 mm, and further three strands were twisted with a yarn density of 8 yarns / cm.
33mm Polyamide monofilament (thread density 6 /
cm) was used. Flat weave and single woven.

Then, a split type bad fiber layer composed of 80% splitting fibers and 20% non-splitting fibers is placed thereon. As this splitting fiber, a composite splitting fiber "Sepa" (product type "DFS-5") manufactured by Daiwa Boshoku Co., Ltd. was used.
The splitting fiber 21 has a circular cross section as shown in FIG. 2, and has a petal portion 211 (including the core portion 211a, which includes a polyamide portion) having an eight-petal shape, and a cross section in which the other portions are divided into eight substantially equal parts. The fan-shaped balance 212 (component is polyester). The wire diameter is 8 denier. This dividing fiber 21
The petal part 211 and the remaining part 212 are divided into fine fibers of each cross-sectional shape by needling. And the undivided fiber 23
As the fiber, a normal fiber (nylon, 6 denier manufactured by DuPont Co., Ltd.) which has been used in a felt for papermaking up to now without having the characteristics of the fiber 21 for division is used. In addition, here
When the purpose of the product is different, the type, properties, etc. of the base cloth, the pad fiber layer, the split fibers, and the non-split fibers can be freely changed.

After that, the split type bad fiber layer and the base cloth etc. are overlapped and needling is performed, and the split type bad fiber layer and the normal bad fiber layer are joined by the fiber hooked on the barb and moving downward. At the same time, this needling splits the splitting fibers in the split-type bad fiber layer into split fine fibers. In the above needling process,
The needle depth of the needling has been made shallow and the number of needlings has been increased. This is because it promotes the splitting of the splitting fibers, but on the other hand, it suppresses the fiber damage of the ordinary bad fiber layer below the splitting type bad fiber layer and further the base fabric. Specifically, the needle depth is 12 mm (usually 16 mm),
The number of needlings was 650 / cm ² (normally 350 / cm ² ). The needle used was a relatively thin 36th needle having 3 barbs (barbs) on each of the 3 edges, for a total of 9 barbs. The barb used had a small protrusion from the ridge. This is because the division of the fiber for division in the surface layer is carried out finely.

From the above, as the needling progresses, the thick splitting fibers are mechanically split, and the splitting fibers in the splitting type bad fiber layer are changed to the fine split fine fibers. A felt having a base layer 1 and a surface layer 2 entangled and integrated with the base layer 1 shown in FIG. 1 was manufactured.
In the needling in the initial stage, since the splitting fibers 21 have a thick shape, they have elasticity, and unlike the one using the ultrafine fibers from the beginning, the surface did not become wavy. In this way, at first, it is elastic and does not recess, and the thick wire diameter is divided and becomes thinner while piercing with the needle,
The desired surface layer 2 of the divided fine fibers 22 was successfully formed while avoiding the defects generated in the conventional manufacturing process.

Structure of Papermaking Felt The actual thickness of the felt is 3.82 mm, and the thickness of the surface layer in the felt is about 0.5 mm. The total weight is 1150 g / m ² and the density is about 0.301 g
/ Cm ³ . The base layer 1 is a relatively coarsely woven base fabric 11
Ordinary bad fiber layer 1 on the upper surface of (Basis weight 250 g / m ² ).
2 (Basis weight 600 g / m ² ), similarly, there is a bad fiber layer 13 (Basis weight 100 g / m ² ) on the lower surface of the base fabric 11,
These are integrated by needling. The surface layer 2 is a non-woven fabric and is composed of dividing fibers (not divided) 21, divided fine fibers 22 (divided), and non-divided fibers (originally indivisible) 23.

The dividing fine fibers 22 are ultrafine fibers, and the dividing fibers 21 are divided to form a part of the surface layer 2 in the process in which the base layer 1 and the surface layer 2 are entangled by needling. is there. 9 petals 211 from one split fiber 21
Since the remaining portion 212 is divided into eight pieces, the thin fibers that are about 1/17 of the original dividing fibers 21 are formed. Unlike the so-called conventional ultrafine fibers, the split fine fibers 22 do not have a disordered form, but have some bundle-like form as shown in FIG.

(2) Examples 2, 3 and Comparative Example In Example 2, the surface layer was formed by using the split type bad fiber layer in which the mixing ratio of the splitting fiber 21 and the non-splitting fiber 23 was 50% to 50%. Configured 2. Overall basis weight 1194 g / m
² , the same specifications as in Example 1 except for the thickness of 4.02 mm and the density of 0.297 g / cm ³ . In Example 3, the mixing ratio of the split fibers 21 and the non-split fibers 23 is 30% to 70%.
The surface layer 2 was constructed using the split type pad fiber layer. Overall weight is 1182 g / m ² , thickness 4.21 m
The specifications are the same as in Example 1 except that m and the density are 0.286 g / cm ³ . As a comparison with the present invention (comparative example), 100%
The surface layer 2 made of undivided fibers was constructed. Overall weight 11
45g / m ² , thickness 4.21mm, density 0.272g
The specifications are the same as in Example 1 except for / cm ³ .

(3) Evaluation The evaluation results of the papermaking felt of the present invention are shown below. Form Papermaking felt according to Example 1 (8 by needling)
The denier dividing fiber 21 is divided into 30 to 40%. 4) shows a cross-sectional morphology (magnification: 15 times). Figure 5
Is a fiber having the same 8 denier as the splitting fiber 21 and the surface layer 2
Fig. 2 shows a felt for papermaking (comparative example) that is configured (magnification: 1
5 times). It was observed that the dividing fibers 21 were divided into the divided fine fibers 22 to form the thin surface layer 2 (near the upper surface of FIG. 4). Next, the surface state of the surface layer 2 of Example 1 is shown in FIG. FIG. 7 shows a fiber (comparative example) composed of the same 8-denier non-split fiber 23 as the split fiber 21. In FIG. 6, the divided fine fibers 22 are divided and thinned.
Are distributed almost uniformly in the surface layer 2. 4 to 7
As can be seen from the above, it was confirmed that the papermaking felt according to the present invention densified only the thin surface layer and improved smoothness.

Further, an enlarged photograph of the surface layer 2 according to Example 1 is shown in FIG. 8 (magnification: 125 times). FIG. 9 shows an enlarged photograph of a normal fiber (comparative example) having the same 8 denier as the splitting fiber 21 (magnification: 125 times). As shown in FIG. 8, the felt for papermaking according to the present invention is divided into divided fine fibers 22 into divided fine fibers 22, but the individual divided fine fibers 22 do not have a disordered shape, and have a certain bundle shape. Is maintained. Then, it was found that the divided fine fibers 22 constituted a dense surface layer. Incidentally, there are some undivided dividing fibers.

Abrasion property etc. By the way, when the fiber of the surface layer becomes thin, it has a negative effect on the abrasion with the rolls. However, even when the compounding ratio of the dividing fiber 21 is 80%, the felt for papermaking according to the present invention is used. Then, when the test was conducted under the following conditions, it was observed that the wear stopped when the wear amount increased by about 10%. Test conditions: Papermaking speed: 820 m / min, press load: 92
kg / cm (load per 1 cm of surface length = linear pressure), water shower pressure; 1.6 kg / cm ² . When the paper was made using such a felt for papermaking, there were almost no defects due to fiber breakage, hair loss, or shedding.

Water Permeability The air permeability of Examples 1, 2 and 3 and the above Comparative Example with 100% undivided fibers was examined. This test was carried out according to JIS 1096 using a Frazier type air permeability tester. The result is shown in FIG. In the figure,
The cross mark shows the air permeability in the state where it is not pressed yet, which is finished by heat setting after needling.
The ∘ mark is the measured value after the product that was heat set after needling and operated for 56 hours under a press load of 62 kgf / cm while showering with water.
The water permeability has a positive correlation with the air permeability. When the air permeability is low, it is difficult for water from the wet paper to pass through the papermaking felt.

The air permeability is as shown in FIG.
Although it decreased as the ratio of 1 increased, a satisfactory result was obtained even when the splitting fiber 21 was 80%. According to the results of various studies, up to 90% was not a practical problem. 90
% Up to 10-30 cm ³ / sec / cm ²
And the function as a papermaking felt that squeezes as much water as possible from the wet paper was maintained. Surface layer 2 in this case
Had a thickness of 0.5 to 0.6 mm. This is because the dense surface layer 2 has a thin structure and does not have such a fluid resistance.

Surface Properties The smoothness of the papermaking felt surface of the present invention was investigated. Splitting fiber 21 and non-splitting fiber 2 as split-type pad fiber layer 2 '
The blending ratio with 3 was variously changed, and the smoothness of the surface was evaluated. The evaluation method is the surface tester (KAWABATA'S EVALUAT
ION SYSTEM-4 SURFACE TESTER KATO IRON WORKS CO., LT
D KYOTOJAPAN). The friction coefficient of the surface of the papermaking felt itself was examined, and its surface characteristics (smoothness) were evaluated. A schematic view of the surface tester is shown in FIG. The test is
The felt A for papermaking is brought into contact with the underside of the friction member 6 (stainless steel, a pin-shaped body in which pins are arranged before using a stapler), and a load of 50 g is applied to the pin-shaped body 6 (on the weight adjusting unit 5). A weight of 5 g was stored.), And the felt A for papermaking was moved to the left and right to determine the friction coefficient. In the figure, 7 indicates a measuring unit. FIG. 12 shows the coefficient of friction for the product according to Example 1 (having 80% splitting fibers). FIG. 13 shows the friction coefficient of 100% undivided fiber for comparison (comparative example).

Regarding the coefficient of friction and its variation, when the splitting fiber is 80%, the corrugation is gentle, and there is little unevenness on the surface, showing the good surface property. Also by the tactile test by hand, it was surely felt that the surface layer became smoother as the blending ratio of the splitting fibers 21 in the splitting type bad fiber layer increased to 30%, 50% and 80%. ..

(4) Effects of the Example In the papermaking felt according to this example, the splitting fibers 21 contained only in the surface layer of the felt were needlinged.
Since it is converted to divided fine fibers 22 for a fine structure,
While maintaining water permeability, the smoothness of the felt surface could be increased and the formation of paper could be improved. The surface layer having this dense structure prevents the water squeezed from the wet paper to the felt to prevent the water from flowing back from the felt to the paper sheet when the felt and the wet paper separate from the press section. Wet can be prevented and the dry steam in the dry part can be saved greatly.

In the needling process, the splitting fiber 2 is also used.
Since 1 is divided into divided fine fibers 22 to form the surface layer 2, there is no defect in the waving phenomenon due to the use of the ultrafine fibers from the beginning, and there is no obstacle to the attachment of the ultrafine fibers to the cylinder during the card process. The manufacturing work was advanced to obtain a papermaking felt with a smooth surface. Furthermore, the divided fine fibers 22 constituting the surface layer are not completely in a disjointed state, and even if the divided fine fibers 22 are divided into the divided fine fibers 22, the bundled form is still retained. From the beginning, there was no hair loss phenomenon that would occur when using ultrafine fibers. The felt quality could be maintained without the phenomenon that the cut ultrafine fibers, which tend to occur when the ultrafine fibers were used, were collected and curled up into balls.

The present invention can be variously modified within the scope of the present invention depending on the purpose and application. That is, the materials, shapes, and the like of the base fabric 11, the pad fiber layers 12 and 13, the splitting fibers 21, and the non-splitting fibers 22 can be appropriately selected according to the purpose and application. For example, with respect to the base cloth 11, the thread type may be changed to polyester or the like depending on the application, and a person who twists the thread thickness also has a diameter of 0.1 to 0.3 m.
m, and the single yarn may have a length of about 0.25 to 0.5 mm. Here, the yarn density becomes smaller as the yarn becomes thicker. The structure is not limited to a flat structure, but may be 1/3 comb weave or the like. Furthermore, instead of the single weave as in this embodiment, a double or triple weave base fabric can be used. Also, good results can be obtained even when the undivided fibers 23 having a denier of 4 to 20 are used.

Further, if the splitting rate into split fine fibers caused by needling is further increased, the surface property is further improved. However, there is also a problem that the constituent fibers are cut or the density becomes excessively large, so that it is preferable to make the division ratio appropriate. In addition to the above, the thickness of the surface layer is 0.35
Good results are shown in the range of up to 1.2 mm. 0.
If it is less than 35 mm, the smoothness may not be sufficient even if split fine fibers are produced, and if it exceeds 1.2 mm, the running felt resistance of the papermaking felt becomes too large and the water permeability decreases.

[0029]

INDUSTRIAL APPLICABILITY As described above, the papermaking felt according to the present invention can form a smooth surface and improve the paper quality while ensuring water permeability, which is an important function of the papermaking felt. In addition, fiber breakage and hair loss phenomenon are less likely to occur.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a papermaking felt shown in Example 1.

FIG. 2 is a cross-sectional view of the splitting fiber used in Example 1.

FIG. 3 is an explanatory view showing a state of split fine fibers in the surface layer of Example 1.

FIG. 4 is a photograph showing a cross section of the felt for papermaking shown in Example 1 and showing the shape of fibers.

FIG. 5 is a photograph showing the shape of fibers, which is a cross-section of a papermaking felt that does not contain dividing fibers.

FIG. 6 is a photograph showing the shape of fibers on the surface of the papermaking felt shown in Example 1.

FIG. 7 is a photograph showing the fiber shape on the surface of a papermaking felt that does not contain fiber for division.

FIG. 8 is a photograph showing the shape of fibers, which is an enlarged surface of FIG.

FIG. 9 is a photograph showing the shape of fibers, which is an enlarged surface of FIG. 7.

FIG. 10 is a graph showing the relationship between the blending ratio of the splitting fibers in the splittable bad fiber layer and the air permeability.

FIG. 11 is a schematic explanatory diagram of a surface tester used for surface characteristics.

FIG. 12 is a graph showing the coefficient of friction of the surface of the product according to Example 1.

FIG. 13 is a graph showing the coefficient of friction of the surface of a papermaking felt that does not contain dividing fibers.

[Explanation of symbols]

1; Base layer, 11; Base cloth, 12; Bad fiber layer, 13; Bad fiber layer, 2; Surface layer, 21; Dividing fiber, 211;
Petal part, 212; Remainder, 22; Divided fine fiber, 23; Non-divided fiber, 5; Weight adjusting part, 6; Friction element, 7; Measuring part, A; Papermaking felt.

Claims (6)

[Claims] 1. A base layer and a surface layer formed on at least one surface of the base layer, wherein the base layer and the surface layer are integrated by needling, and the surface layer is formed by needling. The splitting fine fibers and the non-splitting fibers are divided, and the mixing ratio of the splitting fibers before being split into the split fine fibers is 40 to 90% by weight with respect to the splitting fibers and the non-splitting fibers. A felt for papermaking, characterized in that 2. The dividing fiber has a circular cross section and has a diameter of 4 to 4.
The papermaking felt according to claim 1, wherein the felt is 20 denier, and the shape formed of one material is an eight-petal type, and the other is a fan-shaped cross section divided into eight substantially equal sections. 3. The surface layer has a thickness of 0.35 to 1.2.
The felt for papermaking according to claim 1 or 2, which has a size of mm. 4. The air permeability is 10 to 30 cm ³ / sec / cm ^2.
The felt for papermaking according to any one of claims 1 to 3. 5. A split type bad fiber layer comprising 40 to 90% by weight of splitting fibers and the non-split fibers constituting the rest is disposed on at least one surface of the base material, and then at least the split type bad fiber is formed. Not only the layer (I) but also the interface portion (II) between the splittable bad fiber layer and the base material is needlessly penetrated to divide the splitting fiber,
The method for producing a felt for papermaking, wherein the interface portion is hooked on a barb by needling and is joined by fibers moving downward. 6. The splitting fibers before the splitting fine fibers are split, have a circular cross-section, have a denier of 4 to 20, and have a shape of one material of 8 petal type, and the other has The method for producing a felt for papermaking according to claim 5, wherein the cross-section has a fan-shaped cross section divided into eight substantially equal parts.