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CN-122013587-A - Hot-pressing reinforcing method for reinforcing fiber interface

CN122013587ACN 122013587 ACN122013587 ACN 122013587ACN-122013587-A

Abstract

The application relates to the technical field of papermaking, and provides a hot pressing reinforcing method for fiber interface reinforcement. The method comprises the following steps of S100, carrying out hot pressing treatment on the wet paper web in a hot pressing area to obtain an intermediate paper web, and S200, carrying out drying and shaping treatment on the intermediate paper web to obtain finished paper. According to the application, pulse pressing pressure is introduced in the medium-pressure stage of the hot pressing treatment, and the pulse pressing pressure and the heating are cooperated to promote the interlayer bonding area to undergo periodical high-pressure compaction and low-pressure rebound, so that the interlayer fibers are driven to undergo controlled rearrangement and embedding, and meanwhile, the directional migration and redistribution of interfacial moisture are promoted, so that the residual water film is reduced, the effective contact area is enlarged, the interlayer bonding strength is enhanced, and the layering is inhibited, thereby solving the problems of low interlayer bonding strength of the multilayer paper and easiness in layering in subsequent processing.

Inventors

  • CHEN JIANBIN
  • ZHOU YURAN
  • MENG TINGTING
  • CHEN QIANRU
  • GUO DALIANG

Assignees

  • 浙江科技大学
  • 浙江华邦新材料有限公司

Dates

Publication Date
20260512
Application Date
20260304

Claims (10)

  1. 1. A method for thermo-compression reinforcement of fiber interface reinforcement, the method comprising the steps of: s100, carrying out hot pressing treatment on the wet paper web in a hot pressing area to obtain an intermediate paper web; S200, drying and shaping the intermediate paper web to obtain finished paper; The hot pressing treatment sequentially comprises a pre-pressing stage P 1 , a medium-pressing stage P 2 and a final-pressing stage P 3 , wherein the medium-pressing stage P 2 applies pulse pressing pressure to the wet paper web to periodically switch the pressing pressure between a high-pressure value P H and a low-pressure value P L , and the P H and the P L meet the following conditions: P H >P L >0,P H /P L =1.5~10。
  2. 2. The hot press enhancing method according to claim 1, wherein the frequency of the pulse pressing pressure is 0.1 to 10hz.
  3. 3. The hot press enhancing method according to claim 1, wherein in S100, the duty ratio D of the pulse pressing pressure is 10 to 90%; where d=t H /（t H +t L ）,t H is the duration of the high voltage value P H in one pulse period, and t L is the duration of the low voltage value P L in one pulse period.
  4. 4. The hot press enhancing method according to claim 1, wherein, in S100, The pressing pressure of the P 1 is 0.1-1.0 MPa, and the temperature is 40-120 ℃; the low pressure value P L of the P 2 is 0.2-2.0 MPa, the high pressure value P H is 0.5-4.0 MPa, and the temperature is 80-200 ℃; the pressing pressure of the P 3 is 1.0-6.0 MPa, and the temperature is 120-230 ℃.
  5. 5. The hot press strengthening method according to any one of claims 1 to 4, wherein P 1 <P L <P H ≤P 3 , and the equivalent average pressure P 2 Are all of the medium pressure stage P 2 satisfies P 1 <P 2 Are all <P 3 ; Where P 2 Are all is a time-weighted average of the hold-down pressures over one or more pulse periods.
  6. 6. The hot press enhancing method according to claim 1, wherein in S200, the drying and shaping process includes a first shaping section T H and a second equalizing section T L which are sequentially performed; the temperature range of the first shaping section T H is 90-180 ℃ and the time is 1-60 min; The temperature range of the second equalization section T L is 50-120 ℃ and the time is 1-120 min.
  7. 7. The hot press enhancement method according to any one of claims 1 to 6, wherein the wet paper web has an in-press dryness of 30 to 65wt% when entering the hot press zone.
  8. 8. The method of claim 7, wherein the press-in dryness is controlled by at least one of vacuum dewatering, press dewatering, pre-drying, atomizing humidification, steam conditioning, or closed-cell humidification.
  9. 9. The thermo-compression reinforcing method as claimed in any one of claims 1 to 8, wherein the wet paper web comprises a multi-layered wet paper web, and an interlayer reinforcing component is applied to an interlayer bonding area of the multi-layered wet paper web before the multi-layered wet paper web enters the thermo-compression area.
  10. 10. The heat and pressure strengthening method of claim 9, wherein the interlayer strengthening component comprises at least one of cationic starch, a dry strength agent, a wet strength resin, microfibrillated cellulose, or a latex binder.

Description

Hot-pressing reinforcing method for reinforcing fiber interface Technical Field The invention relates to the technical field of papermaking, in particular to a hot pressing reinforcing method for fiber interface reinforcement. Background Multi-layer paper is widely used for products such as packaging paper, paperboards, functional composite paper and the like. The multi-layer structure can be respectively provided with long fibers, short fibers, fillers and functional auxiliaries in different layers so as to realize comprehensive balance among stiffness, strength, surface performance and cost. However, in the process of forming, pressing, drying and subsequent coating, laminating, die cutting, folding and the like, the interface between layers often becomes a weak area, and the bonding strength between layers is easily insufficient, so that defects such as delamination, foaming or interlayer peeling occur under the condition of stress concentration or repeated bending. Insufficient interlayer bonding strength is usually related to factors such as insufficient effective contact area between layers, difficulty in eliminating interfacial residual water film, uneven distribution of interlayer fines, insufficient degree of fiber embedment, and the like. The prior art often improves the interlayer bonding strength by increasing the press pressure, increasing the press time, increasing the press temperature, or increasing the interlayer reinforcing component. However, the adoption of a continuous constant higher pressing pressure can easily cause the rapid closing of the interface pore canal between layers, the limitation of the external drainage channel of the interface moisture, the local formation of a residual water film or a closed water layer, thereby inhibiting the controlled rearrangement and embedding of fibers between layers, and in addition, the dynamic adjustment space of the interlayer microstructure under continuous high pressure is insufficient, so that a sufficient fiber interpenetrating and stable joint network is difficult to form at the interface. The adoption of the chemical reinforcing component can improve the combination to a certain extent, but can bring the problems of cost rise, system adaptation, operation stability improvement and the like. Accordingly, there is a need for a hot press strengthening method for fiber interface strengthening to solve the above-mentioned problems. Disclosure of Invention The invention solves the problem of how to provide a hot pressing reinforcing method for fiber interface reinforcement. In order to solve the above problems, the present invention provides a hot pressing reinforcing method for fiber interface reinforcement, the method comprising the steps of: S100, carrying out hot pressing treatment on the wet paper web in a hot pressing area to obtain an intermediate paper web; S200, drying and shaping the middle paper web to obtain finished paper; The hot pressing treatment sequentially comprises a pre-pressing stage P 1, a middle-pressing stage P 2 and a final-pressing stage P 3, wherein the middle-pressing stage P 2 applies pulse pressing pressure to the wet paper web, so that the pressing pressure is periodically switched between a high-pressure value P H and a low-pressure value P L, and the P H and the P L meet the following conditions: PH>PL>0,PH/PL=1.5~10。 in the technical scheme, the frequency of the pulse pressing pressure is 0.1-10 Hz. In the above technical solution, in S100, the duty ratio D of the pulse pressing pressure is 10-90%, where d=t H/（tH+tL）,tH is the duration of the high pressure value P H in one pulse period, and t L is the duration of the low pressure value P L in one pulse period. In the technical scheme, in S100, the pressing pressure of P 1 is 0.1-1.0 MPa, the temperature is 40-120 ℃, the low-pressure value P L of P 2 is 0.2-2.0 MPa, the high-pressure value P H is 0.5-4.0 MPa, the temperature is 80-200 ℃, the pressing pressure of P 3 is 1.0-6.0 MPa, and the temperature is 120-230 ℃. In the above technical scheme, P 1<PL<PH≤P3 and the equivalent average pressure P 2 Are all of the medium pressure stage P 2 satisfy P 1<P2 Are all <P3, wherein P 2 Are all is a time weighted average of the pressing pressures in one or more pulse periods. In the above technical scheme, in S200, the drying and shaping treatment includes a first shaping section T H and a second equalization section T L which are sequentially executed, the temperature range of the first shaping section T H is 90-180 ℃ for 1-60 min, the temperature range of the second equalization section T L is 50-120 ℃ for 1-120 min. In the technical scheme, the press dryness of the wet paper web is 30-65wt% when the wet paper web enters the hot pressing area. In the technical scheme, the inlet pressure dryness is regulated and controlled by at least one of vacuum dehydration, squeezing dehydration, predrying, atomization humidification, steam humidity regulation or closed humidit