A papermaking felt for copy paper production

Abstract

The utility model relates to the technical field of copying paper production, concretely to a papermaking blanket for copying paper production, including base support layer, the base support layer top is equipped with transition bonding layer, first hair net layer and second hair net layer in proper order, the first hair net layer is by skin core type bicomponent short fiber and is with 45 degree oblique way intertexture of paving, the second hair net layer is by superfine denier special section monofilament fiber and is with 0 degree longitudinal high density paving forms, the transition bonding layer is inlayed and is equipped with a plurality of vertical anchoring fiber bundle, vertical anchoring fiber bundle penetrates first hair net layer and partly inlayed second hair net layer, the fiber cross region of first hair net layer and second hair net layer forms local melting consolidation point through heat treatment. The papermaking blanket for copying paper production is stable in structure, is not easy to lose hair, is smooth on the surface, is uniform in dehydration, can effectively guarantee the transparency and cleanliness of copying paper.

Description

Technical Field

[0001] This utility model relates to the field of copy paper production technology, specifically to a papermaking blanket for copy paper production. Background Technology

[0002] Copy paper is a thin, translucent specialty paper with a high surface finish, widely used in printing, packaging, and art reproduction. In high-speed papermaking, the papermaking felt, as a crucial dehydration and support element, directly affects the paper's forming quality and operational stability. Therefore, given the unique physical properties of copy paper, specially designed felts are required to meet its production process requirements.

[0003] Currently, most papermaking felts used in the production of copy paper on the market adopt a single-layer or conventional composite structure, with the web layer typically woven from a single component of fibers. In actual use, this type of structure is prone to surface fiber loosening or even shedding due to insufficient bonding between fibers under high-speed operation and repeated pressing, resulting in a rough felt surface, uneven dehydration, and the potential to carry lint onto the paper surface, affecting the transparency and cleanliness of the copy paper. At the same time, the surface structure of traditional felts lacks precise control over fiber orientation and distribution density, making it difficult to balance surface smoothness and internal support strength, and thus failing to effectively match the comprehensive performance requirements of copy paper for lightweight, light transmission, strength, and uniformity. Utility Model Content

[0004] The purpose of this utility model is to provide a papermaking blanket for copy paper production, so as to solve the problems mentioned in the background art, that the current papermaking blankets used in copy paper production are prone to shedding, have rough surfaces, and uneven dehydration due to insufficient fiber bonding and unreasonable structural design, which in turn affect the transparency and cleanliness of the paper.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a papermaking felt for copy paper production, comprising a base support layer, a transition bonding layer, a first web layer, and a second web layer sequentially disposed above the base support layer. The first web layer is composed of core-sheath type bicomponent short fibers interwoven in a 45° oblique web laying manner. The second web layer is formed by ultra-fine denier irregular cross-section monofilament fibers laid in a 0° longitudinal high-density web. The transition bonding layer is embedded with a plurality of vertically anchored fiber bundles, which penetrate the first web layer and are partially embedded in the second web layer. The fiber intersection area between the first web layer and the second web layer is heat-treated to form a local melting and solidification point.

[0006] Preferably, the ultrafine denier irregular cross-section monofilament fiber in the second wool web layer has a Y-shaped cross-section structure, a fineness of 0.15 dtex, an adjacent fiber spacing of 0.05–0.08 mm, and micron-level guiding grooves are provided on the fiber surface along the axial direction.

[0007] Preferably, the core-sheath bicomponent short fibers in the first web layer are polyester and polypropylene composite structures, with a single fiber length of 6.3 mm, each bundle containing 4 fibers with a fineness of 0.3 dtex, and a web density of 250 g / m².

[0008] Preferably, the base support layer is woven from warp polyester monofilaments and weft nylon multifilaments into a mesh-like frame structure, with the mesh aperture decreasing in a gradient from bottom to top, ranging from 1.2 mm to 0.8 mm.

[0009] Preferably, the vertically anchored fiber bundle is made of low-melting-point copolyester filaments with a diameter of 0.2 mm, distributed in an array with 6–10 filaments per square centimeter, and its upper end is branched in an umbrella shape and embedded inside the second woolen web layer.

[0010] Preferably, the angle between the web laying direction of the second web layer and the web laying direction of the first web layer is 45°, and the two layers of fibers form an interlocking interwoven structure in three-dimensional space.

[0011] Compared with existing technologies, the beneficial effects of this invention are: the papermaking felt used for copy paper production has a stable structure, is not prone to shedding, has a fine surface, and is uniformly dehydrated, effectively ensuring the transparency and cleanliness of the copy paper. This papermaking felt for copy paper production enhances the interlayer bonding strength through the synergistic cooperation of the base support layer, transition bonding layer, and vertically anchored fiber bundles. The first web layer uses a core-sheath type bicomponent short fiber obliquely laid web, and forms localized melting and solidification points with the second web layer under heat treatment, significantly improving the cohesion between fibers. Simultaneously, the high-density longitudinal web structure of the second web layer ensures the compactness and smoothness of the contact surface. The overall design effectively suppresses fiber shedding and uneven moisture distribution during operation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the papermaking blanket structure for producing copy paper according to this utility model; Figure 2 This is an exploded structural diagram of the top of the base support layer of a papermaking blanket for copy paper production according to this utility model. Figure 3 This is a top view schematic diagram of the transition bonding layer of a papermaking blanket for copy paper production according to this utility model.

[0013] In the diagram: 1. Base support layer; 2. Transition bonding layer; 3. First web layer; 4. Second web layer; 5. Vertical anchoring fiber bundle. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0015] Please see Figure 1-3This utility model provides a technical solution: a papermaking felt for copy paper production, comprising a base support layer 1, a transition bonding layer 2, a first web layer 3, and a second web layer 4 sequentially disposed above the base support layer 1. The base support layer 1 and the transition bonding layer 2 are mechanically interlocked through a needle-punching composite process, with the needle-punching depth controlled at 0.5–0.8 mm, so that the low-melting-point short fibers form a barbed structure during the puncture process, enhancing the interlayer anti-peeling ability. The first web layer 3 is composed of core-sheath type bicomponent short fibers interwoven in a 45° oblique web laying manner, and the second web layer 4 is composed of ultra-fine denier irregular cross-section monofilament fibers laid in a 0° longitudinal high-density web. The transition layer 2 is formed by embedding several vertically anchoring fiber bundles 5. The lower ends of the vertically anchoring fiber bundles 5 are partially fused and bonded to the weft nylon multifilaments of the base support layer 1 by hot pressing. The upper umbrella-shaped branching structure is pre-placed before the second web layer 4 is formed, and is heated synchronously with the ultra-fine denier monofilament fibers in the subsequent hot air setting process to achieve physical anchoring and interface fusion. The vertically anchoring fiber bundles 5 penetrate the first web layer 3 and are partially embedded in the second web layer 4. The fiber intersection area of ​​the first web layer 3 and the second web layer 4 is heat-treated to form a partially fused solidification point. This structure provides overall mechanical support to the base support layer 1 and maintains the operation of the blanket. For stability, the transition bonding layer 2 firmly connects the first web layer 3 and the second web layer 4 through embedded vertical anchoring fiber bundles 5. This effectively suppresses relative displacement between the web layers during high-speed pressing. The first web layer 3 uses core-sheath type bicomponent short fibers interwoven in a 45° oblique web laying manner. During heat treatment, its sheath material melts and forms localized melting and solidification points at the intersection area with the ultra-fine denier irregular cross-section monofilament fibers laid at a high density in the second web layer 4 at 0° longitudinal direction. This significantly improves the bonding strength between the two web layers. This multi-layer synergistic structure works together during paper machine operation to ensure surface contact... The second web layer 4 of the paper sheet maintains a high degree of density and fineness. At the same time, the first web layer 3 and the vertically anchored fiber bundles 5 provide resistance to deformation and structural integrity, effectively preventing the surface fibers from loosening and falling off, avoiding lint contamination of the paper surface, and ensuring that moisture is evenly discharged along the fiber gaps and micropore channels. This solves the problems of lint removal, surface roughness, and uneven dehydration caused by the weak bonding force of single-component fibers and easy peeling between layers in the existing technology. It meets the stringent production requirements of copy paper for high cleanliness, high transparency, and uniform forming. The ultra-fine denier irregular cross-section monofilament fibers in the second web layer 4 have a Y-shaped cross-section structure, a fineness of 0.15 dtex, and an adjacent fiber spacing of 0.05–0.The fiber has a diameter of 0.08 mm and micron-level drainage grooves along its axial direction. In this structure, the Y-shaped cross-section monofilament fibers in the second web layer 4 work synergistically with the micron-level drainage grooves along the surface to increase the fiber's specific surface area and form directional water-guiding channels, allowing water to be rapidly discharged along the axial direction. This effectively improves dewatering efficiency and paper uniformity, while also enhancing surface density and reducing lint shedding and paper surface defects. The core-sheath type bicomponent short fibers in the first web layer 3 are a polyester and polypropylene composite structure, with a single fiber length of 6.3 mm. Each bundle contains four fibers with a fineness of 0.3 dtex, and the web density is 250. In this structure, the core-sheath bicomponent short fibers in the first web layer 3 undergo a heat treatment process where the polypropylene sheath melts and bonds with adjacent fibers, forming a robust three-dimensional network structure. This significantly enhances the intralayer bonding strength and peel resistance, effectively preventing fiber loosening and shedding during high-speed operation. Simultaneously, it maintains good elasticity and breathability, providing stable support for the second web layer 4. The base support layer 1 is a mesh-like frame structure woven from warp polyester monofilaments and weft nylon multifilaments. The mesh aperture decreases gradually from bottom to top, ranging from 1.2 g / m². The gradient pore size design of the base support layer 1, ranging from 0.2 mm to 0.8 mm, allows water to flow directionally from the dense upper layer to the loose lower layer during pressing, reducing rewetting. Simultaneously, the composite weaving of polyester monofilaments and nylon multifilaments balances high rigidity and flexibility, effectively maintaining the stability of the blanket's operation and extending its service life. The vertically anchoring fiber bundle 5, made of low-melting-point copolyester filaments with a diameter of 0.2 mm, is distributed in an array of 6–10 filaments per square centimeter. Its upper end branches in an umbrella shape and embeds itself within the second web layer 4. This structure vertically anchors… Fiber bundle 5 is firmly embedded in the second web layer 4 through its umbrella-shaped branching ends, forming a mechanical anchor with the underlying structure. This effectively suppresses relative displacement between layers during high-speed operation and repeated pressing, significantly improving interlayer bonding strength and preventing the shedding of delamination and surface fibers. The layup direction of the second web layer 4 forms a 45° angle with the layup direction of the first web layer 3. The two layers of fibers form an interlocking, interwoven structure in three-dimensional space. This structure effectively improves the overall structure's shear resistance and dimensional stability, while simultaneously inhibiting displacement or loosening of the surface fibers during high-speed operation.

[0016] Working principle: When using this papermaking felt for paper production, the base support layer 1 is first installed on the surface of the rollers in the press section of the paper machine. Then, the transition bonding layer 2, the first web layer 3, and the second web layer 4 are sequentially attached to the base support layer 1 to form an integral structure. The wet paper sheet is transferred from the forming wire to the surface of the second web layer 4 and enters the pressing zone between the press rollers along with the felt. Under pressure, water is squeezed out from the wet paper sheet and seeps into the second web layer 4. It is then conducted downwards to the first web layer 3 through the internal fiber gaps and micron-level guide grooves, and then continues to be discharged downwards through the pore channels between the first web layer 3 and the base support layer 1. At the same time, the vertically anchored fiber bundle 5 penetrates the transition bonding layer 2 and the first web layer 3 and is embedded inside the second web layer 4, keeping the position of each layer fixed during the pressing process. After pressing, the felt enters the cleaning and drying area with the circulation operation. The water is finally discharged from the bottom of the base support layer 1, completing the entire process of dewatering, conveying, and circulation, thus completing a series of tasks.

[0017] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A papermaking felt for producing copy paper, comprising a base support layer (1), characterized in that: The base support layer (1) is provided with a transition bonding layer (2), a first web layer (3) and a second web layer (4) in sequence. The first web layer (3) is composed of core-sheath type bicomponent short fibers interwoven in a 45° oblique web laying manner. The second web layer (4) is formed by ultra-fine denier irregular cross section monofilament fibers laid in a 0° longitudinal high-density web. The transition bonding layer (2) is embedded with a number of vertical anchoring fiber bundles (5). The vertical anchoring fiber bundles (5) penetrate the first web layer (3) and are partially embedded in the second web layer (4). The fiber intersection area of ​​the first web layer (3) and the second web layer (4) is heat-treated to form a local melting and solidification point.

2. The papermaking felt for producing copy paper according to claim 1, characterized in that: The ultrafine denier profiled monofilament fiber in the second wool layer (4) has a Y-shaped cross-section structure, a fineness of 0.15 dtex, a spacing between adjacent fibers of 0.05–0.08 mm, and micron-level guiding grooves are provided on the fiber surface along the axial direction.

3. The papermaking felt for producing copy paper according to claim 1, characterized in that: The core-sheath bicomponent short fibers in the first web layer (3) are polyester and polypropylene composite structures, with a single fiber length of 6.3 mm, each bundle containing 4 fibers with a fineness of 0.3 dtex, and a web density of 250 g / m².

4. The papermaking felt for producing copy paper according to claim 1, characterized in that: The base support layer (1) is woven from warp polyester monofilaments and weft nylon multifilaments into a mesh-like frame structure, with the mesh aperture decreasing in a gradient from bottom to top, ranging from 1.2 mm to 0.8 mm.

5. The papermaking felt for producing copy paper according to claim 1, characterized in that: The vertically anchored fiber bundle (5) is made of low-melting-point copolyester filaments with a diameter of 0.2 mm. It is distributed in an array with 6–10 filaments per square centimeter. Its upper end is branched in an umbrella shape and embedded inside the second woolen web layer (4).

6. The papermaking blanket for producing copy paper according to claim 1, characterized in that: The lay-up direction of the second web layer (4) is at an angle of 45° to the lay-up direction of the first web layer (3), and the two layers of fibers form an interlocking interwoven structure in three-dimensional space.

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