CN101725074B

CN101725074B - Method for increasing retention of paper filler

Info

Publication number: CN101725074B
Application number: CN2009100238998A
Authority: CN
Inventors: 林涛; 殷学风
Original assignee: Shaanxi University of Science and Technology
Current assignee: Shaanxi University of Science and Technology
Priority date: 2009-09-14
Filing date: 2009-09-14
Publication date: 2012-05-23
Anticipated expiration: 2029-09-14
Also published as: CN101725074A

Abstract

The invention discloses a method for increasing retention of paper filler. The method comprises the steps of: making fiber pass through a 200-mesh sieve first; then premixing 10 to 25 percent (relative to the mass percentage of absolute dry fiber) of fiber and 15 to 50 percent (relative to the mass percentage of the absolute dry fiber) of filler uniformly, wherein the filler is ground calcium carbonate, precipitated calcium carbonate, kaolin, talcpowder or titanium dioxide; then adding 0.05 to 0.15 percent (relative to the mass percentage of the absolute dry fiber) of cationic polyacrylamide (CPAM) into the mixture at the stirring speed of between 500 and 1,500r/min to form a flocculation group which can pass through a 20-mesh sieve; adding the flocculation group into a pressure screen or the front end of a headbox; and finally, performing papermaking formation and drying on a paper machine to produce qualified paper. The method can increase the retention of the filler, and also improve the strength performance of paper sheets.

Description

A kind of method that improves retention of paper filler

Technical field

Belong to the paper industry field, particularly a kind of method that improves retention of paper filler.

Background technology

Nowadays pulp and paper industry is experiencing huge change.Pulping and papermaking industry is given the bad impression of people's high energy consumption, high pollution always, therefore must be through saving material and the energy, and reduce discarded object and satisfy the new demand of consumer and keep competitiveness.In recent years, made paper more and more come to approach in order to reduce cost, quantitatively more and more lower.And filler be most of cultural papers must obligato composition; It not only can improve performances such as paper of whiteness, opacity, smoothness, air permeability; And can also improve the water filtering performance of slurry, the steam consumption in the reduction paper dryer process, also be one of target of producer's pursuit so improve filer content.But because the particle diameter of filler is much smaller than the perforate of forming web, thereby retention is very low; And the adding of filler has influenced interfibrous combination, especially low quantitatively, during high filler content, its strength character sharply descends.Therefore reduce at the same time under the situation of Substance and raising filer content, how guaranteeing or improving paper strength is a difficult problem that paper-making industry faces at present.

At present, the super technology of filling out that adds is being studied in Northern Europe, mainly is carbon dioxide is fed the aqua calcis that is mixed with fiber fines, and the calcium carbonate of generation is adsorbed on the fiber fines, then it is added in the slurry as filler.The advantage of the method is: a: filler retention is very high, and in paper, is evenly distributed, and can give the good optical property of paper (high light scattering coefficient, high opacity); B: the retention of fiber fines is high, because its higher surface area exposes more hydrogen bond, thereby helps improving strength of paper.Shortcoming is exactly: complex process, cost is higher.The cell lumen loading technology of North America then is that carbon dioxide is fed in the saturated aqua calcis of slurry; Carbon dioxide and calcium hydroxide molecule all can get into lumen through the cinclides of fiber, and the water-fast precipitation of calcium carbonate that makes generation is in lumen.The advantage of the method is: the loose calcium carbonate of fiber outer wall absorption is removed through the method for washing, thereby does not influence strength of paper; Calcium carbonate in the chamber is not influenced by washing then, does not even receive the influence of secondary recovery.But through cell lumen loading, filer content is low.Domestic also have the people that this was done research, and the result almost can't see filler in lumen, thus this technology to implement difficulty very big.

The factor of decision paper strength mainly contains 2 points: the one, and the intensity of fibrous raw material itself; The 2nd, the bond strength between fiber and the fiber (hydrogen bonded).The adding of conventional filler makes between fiber the contact area reduce and contact the distance increase, thereby influences interfibrous hydrogen bonded, causes the decline of paper strength.The present invention improves in the paper filer content mainly based on following thinking through fiber fines: 1. fiber fines and filler wadding gathers, and forms bigger wadding and gathers group, easy by county Party committee's network catch and, the raising filler retention; 2, fiber fines has high surface area, is 10-50 times of fiber, makes its hydroxyl that exposes more times, helps improving interfibrous bond strength, remedies the loss of strength that is caused by the adding of filler.Scheme of the present invention is directly filler to be added to contain in the middle of the slurry of a certain amount of fiber fines, makes it wadding with cationic polymer again and gathers, and the wadding that forms certain specification gathers group, adding in the paper stock online then and manufacturing paper with pulp.The method super relatively adding, fill out and cell lumen loading, and be simple for process, and more feasible.

Summary of the invention

It is not enough to the objective of the invention is to overcome above-mentioned prior art, and a kind of method that improves retention of paper filler is provided, and the present invention can improve the retention of filler, can improve the paper strength performance again.

Technical scheme of the present invention is achieved in that

Filler (like powdered whiting, precipitated calcium carbonate, kaolin, talcum powder, the titanium dioxide etc.) premix of the fiber fines that passes through 200 mesh sieves of 10%-25% (with respect to the bone dry fiber mass percent) and 15%-50% (with respect to the bone dry fiber mass percent) is even, and the PAMC (being called for short CPAM) that under the mixing speed of 500 commentaries on classics/min-1500 commentaries on classics/min, adds 0.05%-0.15% (with respect to the bone dry fiber mass percent) then makes it to form and can gather group through the wadding of 20 mesh sieves.This wadding gathered add before pressurized screen or the head box, on the paper machine, manufacture paper with pulp at last shaping, drying are produced qualified paper.

Present technique adopts the preparatory wadding of retention agent CATION polyphenyl propionamide to gather fiber fines and filler, because electrostatic adsorption, fiber fines and filler wadding that the CATION polyphenyl propionamide of long strand will be anionic property gather, and forming wads a quilt with cotton gathers group.The formation that wadding gathers group has following influence to the performance of the manufacturing paper with pulp of page, paper:

1) because wadding gathers the particle diameter of group much larger than the particle diameter of filler grain or fiber fines, thus make its more be prone to by network of fibers catch and, thereby improved the retention of filler and fiber fines, reduced the white water consistency of paper machine.

2) since wadding to gather granule the footpath bigger, the filler in the page is washed off the degree minimizing under the washing away of plain boiled water, thereby it is poor also to have reduced the two sides of page.

3) because retention agent is prior and fiber fines and filler premix, avoided directly contacting, reduced the degree that the fibrous raw material wadding gathers, improved the evenness of page, thereby helped improving the intensity of page with fibrous raw material.

4) retention agent does not directly contact with fibrous raw material, has avoided fibrous raw material to consume retention agent, thereby can significantly reduce the consumption of retention agent, reduces the cost of chemicals.

5) fiber fines has fiber 10-50 specific area doubly; After fiber fines and filler wadding gathered, be wrapped in around the filler, can form hydrogen bonded more with fiber; Thereby remedy the shortcoming that filler disturbs paper strength, help improving the intensity of the page of high filler content.

Description of drawings

The CPAM consumption is to the influence of filler retention under the different machine hand's skill of Fig. 1 condition

In the different machine hands' skills of Fig. 2 filler page Z-to distribution

Fig. 3 is different, and the machine hand plants down the relation of content of ashes in drainage time, paper permeability, formation of sheet index and the page;

Fig. 4 is different, and the machine hand plants down the relation of content of ashes in paper tear index, tensile index, density and the page.

Below in conjunction with accompanying drawing content of the present invention is done further explain.

The specific embodiment

This technology and traditional handicraft (earlier filler is added in the paper stock, before head box, add CPAM again, copy paper) are done contrast, can find that under the consumption of identical CPAM, the filler retention of this technology is apparently higher than traditional handicraft, and is as shown in Figure 1.The CPAM of this process using 0.03% (to the oven dry stock mass percent), its filler retention reaches more than 55%, and the consumption of traditional handicraft CPAM is when reaching 0.15% (to the oven dry stock mass percent), filler retention can only reach about 35%.Filler wad a quilt with cotton in advance polymerizing technology (filler and CPAM premix, add head box again before, copy paper) compare with this technology, under identical CPAM consumption, though its retention is high slightly, the two sides of having strengthened page is poor, and is as shown in Figure 2.Thereby this technology can significantly improve the retention of filler, and the two sides that can reduce page again is poor.

In three kinds of different machine hand's skills; Traditional handicraft causes the retention of filler very limited because fibrous raw material has adsorbed the part retention agent, thereby causes in the page content of ashes to be difficult to improve; And the evenness index of page is higher; And after content of ashes 15% (CPAM consumption 0.10%), sharply rise, show that the evenness of page worsens rapidly, as shown in Figure 3.At identical content of ashes scope class (14%-17%), drainage time of this technology and air permeability and traditional handicraft basically identical.Compare with the filler polymerizing technology of wadding a quilt with cotton in advance, the drainage time of this technology prolongs slightly to some extent, mainly is that fines retention is higher than filler and wads a quilt with cotton in advance due to the polymerizing technology in this technology.Fiber fines has higher specific surface area, thus the raising of fines retention cause that page combines tightr, make that page density rises, tensile strength rises, air permeability descends, the curve of Fig. 3 and Fig. 4 has also been verified this conclusion.The tear index of paper depends on the length of interfibrous adhesion and fiber; Wherein the length of fiber plays a major role; Thereby the raising of fines retention reduced the average length of fiber, thereby causes the tear index of this technology to be lower than the filler polymerizing technology of wadding a quilt with cotton in advance, and is as shown in Figure 4.

In sum, though filler is wadded a quilt with cotton in advance polymerizing technology improve filler to keep effect best because the distribution evenness variation of its filler is unfavorable for its popularization.And this technology can improve the retention of fiber fines and filler simultaneously, compares with traditional handicraft, can significantly improve content, the consumption that reduces chemicals, the raising paper strength of filler in page.

To 60SR-90SR, adopt the above pulp classifier of 200 orders to sieve out the fiber fines in the slurry pulp beating.The fiber fines (with respect to quality of fiber percentage) of 10%-25% is even with filler (with respect to the quality of fiber percentage) premix of 15%-50%, and the PAMC (being called for short CPAM) that under certain mixing speed, adds 0.05%-0.15% then makes it to form and can gather group through the wadding of 20 mesh sieves.This wadding gathered add before pressurized screen or the head box, the shaping of on the paper machine, manufacturing paper with pulp at last, drying is produced qualified paper.

Claims

1. method that improves retention of paper filler is characterized in that:

Earlier fiber is passed through 200 mesh sieves; Then will with respect to the bone dry fiber mass percent be after 10%-25% sieves fiber be that the filler premix of 15%-50% is even with respect to the bone dry fiber mass percent; Under the mixing speed of 500-1500 commentaries on classics/min, adding with respect to the bone dry fiber mass percent then is the PAMC CPAM of 0.05%-0.15%; Formation can gather group through the wadding of 20 mesh sieves; This wadding is gathered a front end that adds pressurized screen or head box, and on the paper machine, manufacture paper with pulp at last shaping, drying are produced qualified paper.

2. a kind of method that improves retention of paper filler according to claim 1 is characterized in that: filler is powdered whiting, precipitated calcium carbonate, kaolin, talcum powder or titanium dioxide.