Search

CN-122008647-A - High-strength digital printing conveyer belt with multilayer structure

CN122008647ACN 122008647 ACN122008647 ACN 122008647ACN-122008647-A

Abstract

The application relates to the technical field of conveyor belts, and discloses a high-strength digital printing conveyor belt with a multilayer structure, aiming at solving the problems of interface stress concentration, thermally-induced dimensional instability and pitch deviation caused by creep. The conveyer belt is characterized in that a transmission friction layer, a bottom bonding transition layer, a composite reinforcing framework layer, a stress compensation layer and a surface printing bearing layer are sequentially arranged from bottom to top. Wherein the skeleton layer adopts a high-modulus para-aramid three-dimensional weaving structure, and the stress compensation layer adopts tungsten zirconium phosphate filler with negative thermal expansion characteristic and an elastomer for composite molding. All layers are integrated through chemical bonding or dipping treatment. Through the scheme, the longitudinal modulus and the dynamic thermal stability of the conveyor belt are obviously improved, the thermal deformation and the edge wrinkling are effectively restrained, and the register precision of high-resolution printing is ensured.

Inventors

  • LI KUNHUI
  • WANG JIA
  • LI LIANGANG

Assignees

  • 青岛环球输送带有限公司

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. The high-strength digital printing conveyor belt with the multilayer structure is characterized in that a transmission friction layer, a bottom bonding transition layer, a composite reinforcing framework layer, a stress compensation layer and a surface printing bearing layer are sequentially arranged on the conveyor belt from bottom to top, and the transmission friction layer, the bottom bonding transition layer, the composite reinforcing framework layer, the stress compensation layer and the surface printing bearing layer are integrated integrally through an interface crosslinking structure to form a composite entity with a preset dynamic modulus gradient; The transmission friction layer is composed of a synthetic rubber base material containing chopped carbon fibers, the lower surface of the transmission friction layer is provided with an anti-skid texture, the bottom adhesion transition layer is composed of an isocyanate modified resin system containing nanoscale silicon dioxide particles, the composite reinforcing framework layer is of a three-dimensional multidirectional weaving structure composed of longitudinal warps, transverse wefts and binding wires, the whole transmission friction layer is subjected to resorcinol-formaldehyde-latex dipping treatment, the stress compensation layer is composed of an elastomer matrix containing fillers with negative thermal expansion coefficients, and the surface printing bearing layer is composed of a high-molecular polyurethane system containing nanoscale aluminum oxide particles and an antistatic network.
  2. 2. The high-strength digital printing conveyor belt with a multi-layer structure according to claim 1, wherein the synthetic rubber base material of the transmission friction layer is hydrogenated nitrile butadiene rubber with the saturation degree of more than 99%, the compression set rate of the synthetic rubber base material at 150 ℃ is less than 15%, the hardness of the base material is Shore A75-85 ℃, 5-8% of chopped carbon fibers are uniformly dispersed in the transmission friction layer, the lengths of the chopped carbon fibers are distributed between 0.5mm and 1.2mm, the chopped carbon fibers are in quasi-oriented arrangement in a rubber matrix to improve the circumferential tensile modulus, the anti-slip texture is a cross grid structure pressed at the bottom of the transmission friction layer, and the depth of the anti-slip texture is 0.2mm to 0.4mm and is used for forming mechanical interlocking with a driving roller through microscopic deformation.
  3. 3. The multilayer structured high strength digital printing conveyor belt according to claim 1, wherein the thickness of the bottom adhesive transition layer is set to 0.15mm to 0.25mm, the layer is formed by a two-component isocyanate modified phenolic resin system as a continuous phase and is highly dispersed with 10% by mass of nanoscale silica particles, the average particle diameter of the nanoscale silica particles is 20nm to 40nm, the bottom adhesive transition layer is in covalent bond connection with rubber molecular chains in a transmission friction layer through isocyanate groups, and physical anchoring and chemical bonding coupling is realized with fiber surface functional groups in a composite reinforcing skeleton layer, so that the interlayer peeling strength is maintained above 12N/mm.
  4. 4. The high-strength digital printing conveyor belt with a multi-layer structure according to claim 1, wherein longitudinal warps in the composite reinforced skeleton layer adopt high-modulus para-aramid filaments with fineness of 1500-3000D, breaking strength of more than 22cN/dtex and initial modulus of more than 450cN/dtex, transverse wefts adopt modified polyester monofilaments with diameters of 0.3-0.5 mm, the binding threads penetrate through the longitudinal and transverse layers to inhibit interlayer slippage, the weaving density of the composite reinforced skeleton layer is defined as 120-10 cm/160-10 cm in the warp direction and 80-10 cm/100-10 cm in the weft direction, the overall impregnation weight gain of the composite reinforced skeleton layer formed by resorcinol-formaldehyde-latex impregnation treatment is 4-6%, and the latex component in the impregnation liquid is a mixture of carboxyl styrene-butadiene latex and butyl chloride latex with a mass ratio of 7:3.
  5. 5. The multilayer structured high strength digital printing conveyor belt according to claim 1, wherein the elastic body of the stress compensation layer is made of thermoplastic polyurethane modified by linear low density polyethylene, the filler with negative thermal expansion coefficient is tungsten zirconium phosphate micropowder with particle size distribution of 1-5 micrometers, the mass ratio of the filler in the elastic body is 12-18%, and the integral linear expansion coefficient of the stress compensation layer is controlled by To the point of In the range, the thermal expansion strain of the matrix material is counteracted by the thermal contraction effect of the tungsten zirconium phosphate micropowder so as to match the thermal deformation characteristic of the surface printing bearing layer and eliminate the edge curl caused by thermal stress.
  6. 6. The multilayer structured high-strength digital printing conveyor belt according to claim 1, wherein the weight average molecular weight of the surface printing bearing layer is distributed between 20 and 30 ten thousand, the flatness deviation of the layer is controlled within +/-0.01 mm, 3 to 5 mass percent of nano alumina particles are added into the surface printing bearing layer, the antistatic network is composed of conductive polyaniline, and an interpenetrating polymer network structure is formed in a polyurethane matrix, so that the surface resistivity of the surface printing bearing layer is maintained at To the point of And the surface of the surface printing bearing layer is subjected to plasma activation treatment, and the surface tension of the surface printing bearing layer is set to 38mN/m to 45mN/m.
  7. 7. A multi-layer structured high strength digital printing belt according to claim 1, wherein the belt has a total modulus of elasticity in the longitudinal tensile direction The following calibration formula is satisfied: wherein Represents the first The volume fraction of the layer material in the thickness direction, Representing the elastic modulus of the ith layer material, and adjusting the volume fraction of para-aramid in the composite reinforced skeleton layer to ensure that The elastic elongation of the conveyer belt is lower than 0.1% under the rated tension and the creep rate after 1000 hours continuous operation is lower than 0.02%, and the stressed neutral layer of the conveyer belt is set at the central plane position of the composite reinforced skeleton layer.
  8. 8. A method of producing a multilayer structured high strength digital printing conveyor belt according to any one of claims 1 to 7, comprising the steps of: 1) The skeleton layer is pretreated, namely the woven composite reinforced skeleton layer passes through a resorcinol-formaldehyde-latex dipping tank, then enters a drying area of 160 ℃ to 180 ℃, and is subjected to longitudinal shaping tension of 150N to 200N per cm width, and is maintained for 3 minutes to 5 minutes to eliminate residual internal stress of fibers; 2) Continuously laminating, namely sequentially compounding a bottom adhesive transition layer, a stress compensation layer and a surface printing bearing layer onto the treated composite reinforced skeleton layer by adopting a multi-head coextrusion or sequential coating process under the melt pressure of 15-25 MPa, wherein a line pressure of 0.5-0.8 MPa is applied by a compression roller in the compounding process so as to eliminate interlayer bubbles; 3) And (3) carrying out gradient vulcanization, namely feeding the compounded blank into a continuous vulcanization press, controlling the vulcanization pressure to be 2.0MPa to 3.5MPa, setting the vulcanization temperature gradient to be that preheating softening is carried out at 120 ℃ for 10 minutes, then core vulcanization is carried out at 165 ℃ for 20 minutes, and cooling to normal temperature at a rate of 5 ℃ per minute after vulcanization is finished.
  9. 9. The method for manufacturing a high-strength digital printing conveyer belt with a multilayer structure according to claim 8, wherein the method further comprises a high-precision grinding process after the step 3), wherein an online thickness monitoring system is used for being linked with an abrasive belt grinder to conduct fine grinding treatment on a surface printing bearing layer, the grinding allowance is controlled to be 0.05mm to 0.10mm, and the surface roughness Ra after grinding reaches 0.4 micrometers to 0.8 micrometers.
  10. 10. The method for manufacturing the high-strength digital printing conveyer belt with the multilayer structure according to claim 8, wherein in the step 2), a closed loop tension sensor is adopted to control longitudinal tension fluctuation of each layer of material at a joint point to be within +/-1%, and a servo drive compensation roller is used for compensating the material speed difference in real time, so that interface compounding of each layer of material is ensured to be completed under the state of no initial strain difference.

Description

High-strength digital printing conveyer belt with multilayer structure Technical Field The invention relates to the technical field of conveyor belts, in particular to a high-strength digital printing conveyor belt with a multilayer structure. Background In the prior art, industrial-grade printing conveyor belts generally adopt a multi-layer composite structure, and the design purpose is to balance the structural strength and the surface characteristics by utilizing the functional complementation of different materials. Typically, the middle layer of such conveyor belts is a reinforcing core layer, often composed of a high strength synthetic fiber fabric (such as polyester or polyamide fibers) to provide the necessary longitudinal tensile stiffness to prevent irreversible plastic elongation under prolonged high load tension, and its upper surface is typically compounded with a layer of an elastomer having a specific coefficient of friction and being resistant to chemical attack (such as polyurethane or polyvinyl chloride) intended to ensure a close fit with the fabric and to resist chemical attack by the printing paste and cleaning aids. The multi-layer composite design well meets the operation requirement of low-speed or medium-speed digital printing equipment in a long period of time in the past, and makes an important contribution to pushing the automation process of the printing industry. Further, the digital printing process is usually accompanied by a drying or heat setting process, and the conveyor belt needs to frequently shuttle between a normal-temperature spray printing area and a high-temperature drying area. Due to the significant difference in thermal expansion coefficients of the synthetic fibers of the reinforcing core layer and the surface elastomeric material, thermal stresses that are difficult to eliminate can develop within the multilayer structure under periodic temperature cycling. The thermal stress can induce the conveyer belt to generate micro-level warpage or edge curling, damage the physical flatness of the printing platform, further cause fluctuation of the distance between the spray head and the fabric, generate displacement deviation or ghost phenomenon, and further accelerate fatigue aging of an interlayer bonding layer, so that catastrophic failures such as local delamination, foaming and the like occur after the conveyer belt is used for a period of time. In order to ensure the transmission precision, technicians usually increase the initial tension of the conveyor belt, but this causes contradiction between creep deformation and stress relaxation of the material, namely, too high tension can increase the instantaneous response speed, but accelerates the molecular chain rearrangement of the framework material, so that the pitch of the conveyor belt is slightly shifted, and the deviation can generate accumulated effect in continuous production for several kilometers, thereby seriously affecting the longitudinal alignment precision of the patterns. As described above, in the conventional multilayer conveyor belt, it is often difficult to achieve excellent interlayer bonding force, thermal mechanical stability, and creep resistance while high strength is being sought. On the premise of ensuring that the conveying belt has extremely high bearing capacity, the problems of stress imbalance, thermal deformation and fatigue delamination in the dynamic service process are fundamentally solved through structural optimization and material collaborative design, and the problems of the key challenges and the technical problems to be solved are presented by the technicians in the field. Disclosure of Invention The invention provides a high-strength digital printing conveyer belt with a multilayer structure, and aims to solve the technical defects of interface stress concentration, thermally induced dimensional instability, pitch deviation caused by material creep and the like of the digital printing conveyer belt in the prior art under the working conditions of high-speed operation and high-frequency temperature change. In order to achieve the aim of the invention, the high-strength digital printing conveyor belt with the multilayer structure is characterized in that a transmission friction layer, a bottom bonding transition layer, a composite reinforcing framework layer, a stress compensation layer and a surface printing bearing layer are sequentially arranged from bottom to top, and all the layers are integrated into a whole through an interface crosslinking structure to form a composite entity with a preset dynamic modulus gradient. The transmission friction layer adopts a synthetic rubber substrate with the hardness of Shore A75-85 degrees, and is uniformly dispersed with 5-8% of chopped carbon fibers with the mass fraction, wherein the length distribution of the chopped carbon fibers is 0.5-1.2 mm. The synthetic rubber base material is hydrogenated nitrile butadiene rubber with the