Preparation device for improving strength of vulcanized fiber surface paper body paper for coating abrasive

Abstract

The invention belongs to the technical field of papermaking, and particularly relates to a preparation device for improving the strength of vulcanized fiber surface paper base paper for coating abrasives, which comprises a paper pulp papermaking device, an extrusion paper forming device, a stress release device, a drying device and a rolling device. Spraying humidification is carried out after the middle layer body paper is output, the water content of the middle layer body paper is made to be higher than that of the upper layer body paper and that of the lower layer body paper, the humidity gradient is formed, and when the three layers of wet-state body paper jointly enter a paper pressing channel formed by the extrusion double rollers, under the action of extrusion force, water of the middle layer is extruded out on the front sides of the extrusion double rollers. Water flow wraps part of free fiber ends of the middle layer when penetrating through the upper layer body paper and the lower layer body paper and stretches towards fiber network gaps of the upper layer body paper and the lower layer body paper, so that fiber-level connection of the three-layer structure is achieved under the condition that chemical adhesives are not used, and the layering risk caused by aging, fatigue or thermal stress concentration of the adhesives is completely eradicated.

Description

Technical Field

[0001] This invention belongs to the field of papermaking technology, specifically relating to a preparation device for improving the strength of base paper for coated abrasive sulfurized fiber paper. Background Technology

[0002] Sulfurized fiber base paper, a cellulose-based material treated with sulfuric acid, has become a key face paper substrate favored by high-performance coated abrasives, especially heavy-duty sanders and high-precision grinding discs, due to its excellent strength, toughness, water resistance, oil resistance, and dimensional stability. This base paper must withstand significant mechanical tension and thermal stress during subsequent processes such as adhesive coating, abrasive application, and curing. Therefore, its face paper strength is a core indicator determining whether the final coated abrasive product possesses high load-bearing capacity, long service life, and stable grinding accuracy.

[0003] Currently, the common technical approach used in the industry to improve the strength of coated abrasive paper substrates is a multi-layer composite paper structure. This method typically involves laminating two or more layers of paper together with adhesives, physically increasing the thickness and overall stiffness of the substrate, resulting in higher tensile and burst strength in static indicators. However, this "thickness over strength" composite method is prone to fatigue failure at the interlayer bonding interface, leading to substrate delamination and severely impacting processing quality and safety. Therefore, multi-layer composites formed through adhesive bonding are a strength improvement solution that relies on the quality of the adhesive and sacrifices the homogeneity and reliability of the substrate, failing to fundamentally meet the stringent requirements of high-end applications for substrate integration and durability. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a preparation apparatus for improving the strength of sulfurized fiber face paper base paper for coating abrasives, which can form a stable interlayer connection structure by means of hydraulic penetration, thereby avoiding the cracking problem of multilayer composite structures in subsequent use.

[0005] The specific technical solution adopted in this invention is as follows: An apparatus for improving the strength of base paper for coated abrasive vulcanized fiber paper includes a pulp forming device, an extrusion forming device, a stress relief device, a drying device, and a winding device. The pulp forming device includes a pulp distributor, a paper conveyor belt, and a smoothing roller positioned above the paper conveyor belt. An extrusion forming roller is located at the output end of the paper conveyor belt. The paper conveyor belt forms the pulp into base paper, which is then drawn from the end of the paper conveyor belt and introduced into the extrusion forming device. The pulp forming device has three sets arranged from top to bottom. The device includes a first upper paper pressing conveyor belt, a second upper paper pressing conveyor belt, and a lower paper pressing conveyor belt. The first and second upper paper pressing conveyor belts abut against the surface of the lower paper pressing conveyor belt to form a paper pressing channel. A squeezing device is added to the abutting surface of the first and lower paper pressing conveyor belts. The squeezing device includes squeezing rollers, which are respectively arranged inside the surface of the first and lower paper pressing conveyor belts. The three layers of base paper drawn from the three sets of pulp forming devices are squeezed by the squeezing rollers when passing through the paper pressing channel.

[0006] The extrusion device also includes an elastic sealing strip, which is sled-shaped and set on the input side of the extrusion rollers. Two sets of sealing strips are set and respectively extrude the edges of the first upper paper conveyor belt and the lower paper conveyor belt to form an abutment seal.

[0007] The extrusion paper forming device is also equipped with a pre-drying device on the output side of the second upper and lower paper conveyor belts. The pre-drying device includes a pre-drying cylinder and a pre-drying chamber. The pre-drying chamber is covered on the outside of the pre-drying cylinder. After the raw paper is squeezed by the second upper and lower paper conveyor belts, it adheres to the pre-drying cylinder and is led out of the pre-drying chamber by the rotation of the pre-drying cylinder and enters the stress relief device.

[0008] The stress relief device includes a stress relief cylinder, a stress guide roller, and a stress rolling roller. The stress relief cylinder and the stress rolling roller abut against each other. After the raw paper is introduced into the stress relief device through the stress guide roller, it passes through the abutment gap between the stress relief cylinder and the stress rolling roller. The raw paper is then introduced into the drying device as the stress relief cylinder rotates.

[0009] A pair of connecting rollers is also installed between the stress relief device and the drying device.

[0010] The drying device includes multiple sets of drying cylinders, which are nested inside the drying chamber and arranged alternately. The self-stress relief device of the base paper is led out and reciprocally wound around the drying cylinder in an S-shape.

[0011] The winding device includes a take-up shaft and a pressure roller. The base paper is wound on the take-up shaft, and the pressure roller abuts against the base paper on the take-up shaft.

[0012] The middle set of three pulp forming units has a water spraying device at the output end of the paper conveyor belt. The water spraying device includes a spray pipe and a water spraying slide. After the raw paper is drawn out from the paper conveyor belt, it slides down the water spraying slide and is moistened by water sprayed from the spray pipe set above the water spraying slide.

[0013] The beneficial effects of this invention are: This invention employs a spray-humidification process after the middle layer of base paper is output, ensuring its moisture content is higher than that of the upper and lower layers, thus creating a humidity gradient. When the three wet base papers enter the pressure channel formed by the extrusion rollers, the moisture in the middle layer is squeezed out under the pressure of the extrusion rollers. As the water flows through the upper and lower base papers, it carries some of the free fiber ends from the middle layer and extends into the fiber network gaps of the upper and lower layers. This achieves fiber-level bonding of the three-layer structure without the use of chemical adhesives, thereby eliminating the risk of delamination caused by adhesive aging, fatigue, or thermal stress concentration. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 for Figure 1 An enlarged schematic diagram of part A in the middle; Figure 3 for Figure 1 Enlarged schematic diagram of part B in the middle; Figure 4 A schematic diagram of a pulp forming apparatus; Figure 5 This is a schematic diagram of an extrusion paper forming apparatus; Figure 6 This is a schematic diagram of a stress relief device; Figure 7 This is a schematic diagram of the drying device; Figure 8 This is a schematic diagram of the winding device; In the attached diagram, 1 is a pulp forming device, 101 is a pulp distributor, 102 is a paper forming conveyor belt, 103 is a smoothing roller, 104 is an extrusion forming roller, 105 is a spray pipe, and 106 is a water spraying plate; 2 is an extrusion paper forming device, 201 is a first upper paper pressing conveyor belt, 202 is a second upper paper pressing conveyor belt, 203 is a lower paper pressing conveyor belt, 204 is an extrusion roller pair, 205 is an edge sealing strip, 206 is a pre-drying cylinder, 207 is a pre-drying chamber; 3 is a stress relief device, 301 is a stress relief cylinder, 302 is a stress guide roller, and 303 is a stress pressing roller; 4 is a drying device, 401 is a drying cylinder, and 402 is a drying chamber; 5 is a winding device, 501 is a winding shaft, and 502 is a pressure roller. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: Specific implementation examples Figure 1 and Figure 2 , Figure 3 As shown, this invention relates to a preparation apparatus for improving the strength of base paper for coated abrasive vulcanized fiber paper, comprising a pulp forming apparatus 1, an extrusion forming apparatus 2, a stress relief apparatus 3, a drying apparatus 4, and a winding apparatus 5. The pulp forming apparatus 1 includes a pulp distributor 101, a paper conveyor belt 102, and a smoothing roller 103 positioned above the paper conveyor belt 102. An extrusion forming roller 104 is located at the output end of the paper conveyor belt 102. The paper conveyor belt 102 forms the pulp into base paper, which is then drawn from the end of the paper conveyor belt and introduced into the extrusion forming apparatus 2. The pulp forming apparatus 1 has three sets arranged from top to bottom. 2 includes a first upper paper pressing conveyor belt 201, a second upper paper pressing conveyor belt 202, and a lower paper pressing conveyor belt 203. The first upper paper pressing conveyor belt 201 and the second upper paper pressing conveyor belt 202 respectively abut against the belt surface of the lower paper pressing conveyor belt 203 to form a paper pressing channel. A squeezing device is added to the abutting surface of the first upper paper pressing conveyor belt 201 and the lower paper pressing conveyor belt 203. The squeezing device includes squeezing rollers 204. The squeezing rollers 204 are respectively arranged inside the belt surface of the first upper paper pressing conveyor belt 201 and the lower paper pressing conveyor belt 203. The three layers of base paper led out by the three sets of pulp forming devices 1 are squeezed by the squeezing rollers 204 when passing through the paper pressing channel.

[0016] The surfaces of the papermaking conveyor belt 102, the first upper paper pressing conveyor belt 201, the second upper paper pressing conveyor belt 202, and the lower paper pressing conveyor belt 203 are all made of water-permeable filter cloth material. Figure 1 and Figures 4 to 8 In the diagram, the dashed line represents the transport path of the raw paper.

[0017] This invention utilizes three sets of pulp forming devices 1 arranged from top to bottom to simultaneously and continuously produce three independent layers of base paper. The base paper is pre-treated by extrusion forming rollers 104 and a paper conveyor belt 102 to remove some moisture and stabilize its shape. The three sets of base paper are then combined and fed into the extrusion forming device 2. This achieves integrated forming from fiber pulp directly to a three-layer composite wet paper web, ensuring that all three layers of base paper are wet and soft in the initial composite stage, providing conditions for subsequent water overflow and rinsing to form fiber interweaving.

[0018] The smoothing roller 103 of the present invention is disposed above the paper conveyor belt 102 and is used to pre-press the pulp in a wet state to form a pulp layer with a relatively uniform thickness.

[0019] Furthermore, such as Figure 3As shown, the extrusion device also includes an elastic sealing strip 205. The sealing strip 205 is sled-shaped and is arranged on the input side of the extrusion roller 204. Two sets of sealing strips 205 are arranged and respectively extrude the edges of the first upper paper conveyor belt 201 and the lower paper conveyor belt 203 to form an abutment seal.

[0020] The edge sealing strip 205 forms a seal by pre-pressing the edges of the first upper pressing paper conveyor belt 201 and the lower pressing paper conveyor belt 203, preventing the fiber-rich pulp from leaking prematurely from both sides during the extrusion process, and promoting the pulp to pass through the paper surface of the upper and lower layers of base paper, thereby improving the yield.

[0021] Furthermore, such as Figure 1 As shown, the extrusion paper forming device 2 is also provided with a pre-drying device on the output side of the second upper paper conveyor belt 202 and the lower paper conveyor belt 203. The pre-drying device includes a pre-drying cylinder 206 and a pre-drying chamber 207. The pre-drying chamber 207 covers the outside of the pre-drying cylinder 206. After the raw paper is extruded by the second upper paper conveyor belt 202 and the lower paper conveyor belt 203, it adheres to the pre-drying cylinder 206 and is led out of the pre-drying chamber 207 by the rotation of the pre-drying cylinder 206 and enters the stress relief device 3.

[0022] After extrusion lamination, the composite wet base paper, which has just completed fiber interlocking and still has a relatively high overall moisture content, undergoes preliminary drying. Appropriately reducing the paper web moisture content helps to fix and strengthen the initially formed fiber interlocking structure, ensuring smooth traction and transfer in subsequent processes. Only one set of pre-drying coil 206 is used, and the drying time is relatively shorter than the formal drying, resulting in a gentler pre-drying process. This avoids shrinkage and deformation of the interlocked fiber network or loosening of the joints due to excessively rapid drying, laying a stable structural foundation for subsequent deep drying and stress release.

[0023] Furthermore, such as Figure 1 As shown, the stress relief device 3 includes a stress relief cylinder 301, a stress guide roller 302, and a stress rolling roller 303. The stress relief cylinder 301 abuts against the stress rolling roller 303. After the raw paper is introduced into the stress relief device 3 through the stress guide roller 302, it passes through the abutment gap between the stress relief cylinder 301 and the stress rolling roller 303. After the raw paper rotates with the stress relief cylinder 301, it is introduced into the drying device 4.

[0024] A pair of connecting rollers is also provided between the stress relief device 3 and the drying device 4.

[0025] After pre-drying, uneven internal stress may be generated inside the base paper due to drying shrinkage and mechanical stretching. The stress relief device 3 of this apparatus, through a stress relief cylinder 301 that rotates in the opposite direction to the pre-drying cylinder 206 and with the help of the pressing rollers, causes the paper web to undergo reverse bending and pressing, effectively releasing internal stress and stretching the internal fiber bundles. This reduces the occurrence of curling and edge warping of the cut base paper during subsequent coating or storage, greatly improving the dimensional stability and flatness of the product.

[0026] Furthermore, the drying device 4 includes multiple sets of drying cylinders 401, which are fitted inside the drying chamber 402 and arranged alternately. The paper self-stress release device 3 is led out and reciprocally wound around the drying cylinder 401 in an S-shape.

[0027] The S-shaped path designed in this invention extends the effective drying distance and time of the paper within the drying chamber 402, achieving efficient and uniform drying. The staggered winding allows both sides of the paper web to alternately contact the surface of the drying cylinder 401, resulting in more uniform drying. Furthermore, the reciprocating winding and forward / backward bending process avoids stress and prevents the paper from curling during use.

[0028] Furthermore, such as Figure 1 As shown, the winding device 5 includes a winding shaft 501 and a pressure roller 502. The base paper is wound on the winding shaft 501, and the pressure roller 502 abuts against the base paper on the winding shaft 501. During the winding process, the pressure roller 502 applies appropriate radial pressure to the paper roll, which can make the paper roll tightly and neatly wound, preventing it from loosening during subsequent handling and storage.

[0029] Furthermore, such as Figure 2 As shown, the output end of the middle set of papermaking conveyor belt 102 of the three sets of pulp making devices 1 is equipped with a water spraying device. The water spraying device includes a spray pipe 105 and a water spraying slide plate 106. After the raw paper is drawn out from the papermaking conveyor belt 102, it slides down the water spraying slide plate 106 and is moistened by water sprayed from the spray pipe 105 set above the water spraying slide plate 106.

[0030] A water spraying device is installed at the output end of the middle layer papermaking device in the three layers to spray and humidify the middle layer base paper. The spraying water volume is slightly lower than the maximum water retention capacity of the middle layer base paper, so that the middle layer base paper can fully absorb the water. No water droplets fall from the lower edge of the water spraying slide plate 106, so that its moisture content is significantly and controllably higher than that of the upper and lower layers, forming a humidity gradient.

Claims

1. An apparatus for improving the strength of base paper for coated abrasive vulcanized fiber paper, comprising a pulp forming apparatus (1), an extrusion forming apparatus (2), a stress relief apparatus (3), a drying apparatus (4), and a winding apparatus (5), wherein the pulp forming apparatus (1) comprises a pulp distributor (101), a paper conveyor belt (102), and a smoothing roller (103) disposed above the paper conveyor belt (102), wherein an extrusion forming roller (104) is disposed at the output end of the paper conveyor belt (102), the paper conveyor belt (102) forms the pulp into base paper, and the base paper is drawn out from the end of the paper conveyor belt and introduced into the extrusion forming apparatus (2), characterized in that: The pulp forming device (1) is arranged in three sets from top to bottom. The extrusion paper forming device (2) includes a first upper paper pressing conveyor belt (201), a second upper paper pressing conveyor belt (202) and a lower paper pressing conveyor belt (203). The first upper paper pressing conveyor belt (201) and the second upper paper pressing conveyor belt (202) respectively abut against the belt surface of the lower paper pressing conveyor belt (203) to form a paper pressing channel. An extrusion device is added to the abutment surface of the first upper paper pressing conveyor belt (201) and the lower paper pressing conveyor belt (203). The extrusion device includes an extrusion roller (204). The extrusion roller (204) is respectively arranged on the inner side of the belt surface of the first upper paper pressing conveyor belt (201) and the lower paper pressing conveyor belt (203). The three layers of base paper drawn out by the three sets of pulp forming devices (1) are extruded by the extrusion roller (204) when passing through the paper pressing channel.

2. The apparatus for preparing base paper for improving the strength of vulcanized fiber face paper for coated abrasives according to claim 1, characterized in that: The extrusion device also includes an elastic sealing strip (205), which is sled-shaped and set on the input side of the extrusion roller (204). Two sets of sealing strips (205) are set and respectively extrude the edges of the first upper paper conveyor belt (201) and the lower paper conveyor belt (203) to form an abutment seal.

3. The apparatus for preparing base paper for improving the strength of vulcanized fiber paper for coated abrasives according to claim 1, characterized in that: The extrusion paper forming device (2) is also provided with a pre-drying device on the output side of the second upper paper conveyor belt (202) and the lower paper conveyor belt (203). The pre-drying device includes a pre-drying cylinder (206) and a pre-drying chamber (207). The pre-drying chamber (207) is covered on the outside of the pre-drying cylinder (206). After the raw paper is extruded by the second upper paper conveyor belt (202) and the lower paper conveyor belt (203), it is attached to the pre-drying cylinder (206) and is led out of the pre-drying chamber (207) by the rotation of the pre-drying cylinder (206) and enters the stress relief device (3).

4. The apparatus for preparing base paper for improving the strength of vulcanized fiber paper for coated abrasives according to claim 1, characterized in that: The stress relief device (3) includes a stress relief cylinder (301), a stress guide roller (302) and a stress rolling roller (303). The stress relief cylinder (301) and the stress rolling roller (303) abut against each other. After the raw paper is introduced into the stress relief device (3) through the stress guide roller (302), it passes through the abutment gap between the stress relief cylinder (301) and the stress rolling roller (303). After the raw paper rotates with the stress relief cylinder (301), it is introduced into the drying device (4).

5. The apparatus for preparing base paper for improving the strength of vulcanized fiber paper for coated abrasives according to claim 1, characterized in that: A pair of connecting rollers is also provided between the stress relief device (3) and the drying device (4).

6. The apparatus for preparing base paper for improving the strength of vulcanized fiber paper for coated abrasives according to claim 1, characterized in that: The drying device (4) includes multiple sets of drying cylinders (401). The drying cylinders (401) are installed inside the drying chamber (402) and are arranged alternately. The paper self-stress release device (3) is led out and reciprocally wound on the drying cylinder (401) in an S-shape.

7. The apparatus for preparing base paper for improving the strength of vulcanized fiber face paper for coated abrasives according to claim 1, characterized in that: The winding device (5) includes a winding shaft (501) and a pressure roller (502). The base paper is wound on the winding shaft (501), and the pressure roller (502) abuts against the base paper on the winding shaft (501).

8. The apparatus for preparing base paper for improving the strength of vulcanized fiber paper for coated abrasives according to claim 1, characterized in that: A water spraying device is provided at the output end of the middle set of paper conveyor belts (102) of the three sets of pulp making devices (1). The water spraying device includes a spray pipe (105) and a water spraying slide plate (106). After the raw paper is drawn out from the paper conveyor belt (102), it slides down along the water spraying slide plate (106) and is moistened by water sprayed from the spray pipe (105) set above the water spraying slide plate (106).

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