A process for producing paper or board and a product thereof

A technology for pulp and fiber, applied in the field of paper or board production, can solve the problems of holes or dark spots, reduce paper quality, printing machine pollution, etc., to reduce the reduction of internal strength, improve runability, improve strength and smoothness degree of effect

Active Publication Date: 2021-07-30
KEMIRA OY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Process equipment is being routinely washed and cleaned as a precautionary measure, resulting in downtime and loss of production
Deposits can also reduce paper quality, cause web breaks, or cause holes or dark spots in the paper, and in extreme cases can lead to paper rejection
[0008] Even low levels of deposits can lead to reduced quality and create problems in the further processing of the produced paper, such as roll breaks during printing, and contamination of printing presses
Although fish eyes can be removed after dissolving the polymer, for example by filtration or centrifugation, this requires the operation and maintenance of additional equipment and wastes part of the polymer

Method used

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  • A process for producing paper or board and a product thereof
  • A process for producing paper or board and a product thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0115] exist figure 1 A diagram according to one embodiment of the invention is given in . The method comprises: adding a high molecular weight polymeric papermaking additive (A) as a powder or an aqueous dispersion to a pulper (1) containing a dry fiber stock. High molecular weight polymeric paper additives are evenly distributed over the stock in the pulper. The stock is directed to a disintegrator and / or refiner (2), from which the crushed and / or refined stock is directed to a mixing tank (3) and from there to a pulping tank ( 4). The stock is then diluted with white water from the white water tank (5) to obtain a thin stock which is directed to the headbox (6) to form a web which is subsequently dried. Optional cationic agent can be added to the mixing box (3), machine chest (4), white water tank (5), before the dilution pump (DP), or after the dilution pump (DP) but after the flow In the thin slurry before the box (6).

Embodiment 2

[0117] exist figure 2 A diagram according to another embodiment of the present invention is given in . The method comprises: feeding a high molecular weight polymeric papermaking additive (AA) as an aqueous dispersion into a fiber line containing an undried fiber slurry, prior to a disintegrator and / or refiner (20), but After the chip line (C) and bleach line (B) of the integrated paper mill. The cracked and / or refined stock is directed to a mixing box (30) and from there to a machine chest (40). The stock is then diluted with white water from the white water tank (50) to obtain a thin stock which is directed to the headbox (60) to form a web which is subsequently dried. The optional cationic agent can be added to the mixing box (30), machine chest (40), white water tank (50), before the dilution pump (DPO), or after the dilution pump (DPO) but after the flow In the thin slurry before the box (60).

Embodiment 3

[0119] The effect of the present invention on fiber refining was tested by adding 2 kg / t high molecular weight CMC to acacia pulp, adding the pulp to a valley beater, and cycling for 30 minutes without load to disintegrate. Acacia pulp without CMC was used as a reference. The same refining time was used for pulp with and without CMC. The Canadian Freeness (in ml) of the pulp was measured according to ISO 5267-2 before and after refining. Due to the water-holding properties of CMC, the addition of CMC reduced the freeness (pulp displacement in milliliters) by about 10% even before refining and by about 18% after refining compared to the reference value. This shows that by using the present method, a higher level of refining (reduced freeness) can be obtained using the same energy, or the same freeness can be obtained using less energy.

[0120] The following tensile strength, z-direction strength and bulk tests were carried out on 80 gsm handsheets made from the above refined...

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Abstract

The present invention provides a process for producing paper or board, comprising slushing a stock of dried fibres in a slushing system comprising a pulper, and / or feeding a stock of never-dried fibres in a fiber line of an integrated paper mill; deflaking and / or refining the stock in a deflaker and / or a refiner, optionally diluting the deflaked and / or refined stock, directing the deflaked and / or refined stock to a headbox, forming a web, and drying the web, wherein a polymeric paper makingadditive is added to one or more of the stocks of dried fibres and never-dried fibres before deflaking and / or refining of the stock. The present invention further provides paper and board with improved properties.

Description

technical field [0001] The invention relates to a method for producing paper or board. The invention also relates to paper and board produced by said method. Background technique [0002] To improve the properties of paper, synthetic resins such as dry strength agents such as acrylamide polymers were first used in the 1940s and early 1950s. Polyacrylamide polymers were found to be effective dry strength resins. Although other types of synthetic dry strength resins are reported in the literature, commercial products are mainly based on acrylamide. [0003] There are many benefits to using strength additives. Refining can be reduced while maintaining paper strength, thereby saving energy. Strength properties can be maintained while replacing expensive, high-quality fiber materials with lower-strength, lower-cost furnishes. Furthermore, dry strength can be increased without a corresponding increase in apparent density, as is the case with increased refining. [0004] In a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21H11/18D21H17/24D21H17/26D21H21/02D21H21/06D21H23/16
CPCD21H11/18D21H17/24D21H17/26D21H21/02D21H21/06D21H23/16D21H17/25D21H17/28D21H17/32D21H17/44D21H17/45D21H11/14D21H11/02D21H11/08D21H11/10D21H27/00D21H5/26D21H21/18D21B1/345D21D1/20D21F1/0018D21H17/29D21H17/55D21H17/56D21H21/20D21H23/04D21J1/00
Inventor 迭戈·萨拉斯李镇晧简-卢伊肯·赫姆斯
Owner KEMIRA OY
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