CN102936866B - Preparation method and application of chitosan modified talcum powder papermaking filler - Google Patents

Abstract

The invention discloses a preparation method and application of chitosan modified talcum powder papermaking filler. The preparation method of chitosan modified talcum powder papermaking filler comprises the following steps of: 1) mixing talcum powder and water and stirring uniformly to obtain mixed liquid, wherein the talcum powder accounts for 5-15% of the mixed liquid by mass; 2) adding chitosan with viscosity of 30-950cps into an acetic acid solution, and stirring uniformly to obtain a chitosan-acetic acid solution with concentration of 2-7g/L; 3) mixing the mixed liquid obtained in the step 1 and the chitosan-acetic acid solution obtained in the step 2, and stirring at a speed of 300-1,100r/min for 5-100min, wherein the mass of the chitosan-acetic acid solution accounts for 1-11% of the total mass of the mixed solution; 4) continuously stirring the mixed solution obtained in the step 3, slowly dropwise adding a sodium hydroxide solution with mass fraction of 5%, and adjusting the pH value of the solution to 6-14; and 5) continuously stirring the solution obtained in the step 4 so that the chitosan molecules adsorbed on the filler surface are cured to form a layer of dense chitosan deposited film to obtain a modified filler suspension.

Description

The preparation method of chitin modified talcum powder papermaking filler and application

Technical field

The invention belongs to paper industry technical field, particularly a kind of chitin modified talcous preparation method and as the application of papermaking filler in papermaking.On the one hand, it mix with talcum powder after being dissolved by shitosan, then shitosan is precipitated out formation modified filler, and its preparation process facilitates, easy to operate, while non-environmental-pollution, coating efficiency high; On the other hand, modified filler is used for paper and adds and fill out, when ash content reaches 30%, add with unmodified talcum powder and fill into paper tensile strength and improve 64%, the retention performance of paper stock also has clear improvement.

Background technology

All the time, filler is widely used in paper industry, and the application of filler not only can significantly reduce cost of material, improve the performance of paper product and class, can also improve paper stock water filtering performance, reduces energy consumption.But, along with the increase adding the amount of filling out, under height is filled, often bring the decline of paper strength performance and filler retention, also can bring the problems such as paper sizing obstacle, hair and powder dropping simultaneously.

About raising paper strength performance, improve filler and keep the lumen that mainly contains fiber with the research of greyness of paper and flber loading, the pre-flocculation of filler, filler/fiber fines complex technique.But due to inorganic filler and pulp fiber poor compatibility, they exist not obvious to the raising of strength character, affect the problems such as the pore structure of paper, make the serviceability of paper be affected.In addition, also there is preparation process complexity, not easily the problem such as suitability for industrialized production and application.

Papermaking filler surface natural polysaccharide coating modification technology is easy, the novel stuffing surface modification method that latest developments are got up.Such natural polymer molecule contains a large amount of hydroxyls, can produce Hydrogenbond with paper pulp fiber, and then improves the inorganic filler of paper and the adhesion of fiber, improves intensity and the retention performance of paper.Starch and derivative, cellulose and derivative etc. are all used for the modification of filler as modifier.But starch based, as large usage quantity during modifier, cost does not have a clear superiority in.Cellulose uses particle liquid, NMMO equal solvent to dissolve as needing during modifier, not only significantly increases the cost of modification, but also there is the inconveniences such as solvent reclaiming trouble.

Summary of the invention

The invention discloses a kind of preparation method and application of chitin modified talcum powder papermaking filler.Shitosan, as a kind of derivative of natural polysaccharide, because it has good biocompatibility, degradability and flocculability etc., is widely used in the industries such as medicine, food, papermaking and printing and dyeing.Talcum powder has good adsorptivity, organic affinity, and shitosan is used for talcous surface modification and carries out in aqueous by the present invention, and it is simple, convenient, has realistic feasibility.

The present invention takes following technical scheme: a kind of preparation method of chitin modified talcum powder papermaking filler, its as follows:

1) talcum powder and water mixed and stir, being mixed with mixed liquor, wherein, talcum powder quality accounts for 5 ~ 15% of mixed liquor quality;

2) be that the shitosan of 30 ~ 950cps adds in acetum by viscosity, and stir, make the chitosan-acetic acid solution that concentration is 2 ~ 7g/L;

3) mixed by the chitosan-acetic acid solution of the mixed liquor of the 1st step with the 2nd step, stir 5 ~ 100min with the speed of 300 ~ 1100r/min, wherein, chitosan-acetic acid solution quality accounts for 1 ~ 11% of mixed solution gross mass;

4) continue the mixed solution of stirring the 3rd step, and be added dropwise to the sodium hydroxide solution that mass fraction is 5%, regulator solution pH value to 6 ~ 14;

5) continue the solution of stirring the 4th step, the chitosan molecule being adsorbed in filling surface is solidified, form the chitosan precipitation film that one deck is closely knit, namely obtain modified filler suspension.

Preferably, in the 1st step, talcum powder quality accounts for 8% of mixed liquor quality.

Preferably, in the 2nd step, the viscosity of shitosan is 800cps, and the concentration of chitosan-acetic acid solution is 6g/L.

Preferably, in the 3rd step, chitosan-acetic acid solution quality accounts for 8% of total mixed solution quality, and mixing speed is 700r/min, and mixing time is 60min.

Preferably, in the 4th step, the pH value regulating mixed liquor is 10.

In technique scheme, the 1st step and the 2nd step can be exchanged, also can reach corresponding technique effect.

The invention also discloses a kind of application of chitin modified talcum powder papermaking filler, it is directly used for papermaking with form of suspension after being washed by modified filler suspension obtained by technique scheme.

The invention also discloses the application of another kind of chitin modified talcum powder papermaking filler, the modified filler suspension obtained by technique scheme carries out filtering, washing by it, obtains filter cake, by filter cake vacuumize at 50 DEG C, grind again, obtain pulverulent filler, for papermaking.

1, the present invention research object and meaning

Paper industry is one of large pillar industry of national economy ten.According to up-to-date national statistics office data display, the 1-6 month in 2012, the first half of this year, China's machine-made paper and cardboard 2,010,000 tons, increase by 2.5% on a year-on-year basis; Paper making and paper product industry accumulative creation sales Value of Industry is 6032.65 hundred million yuan, increases by 13.02% on a year-on-year basis ^[1], China has become the big country of the second largest paper product production and consumption being only second to the U.S..But China is the country of a forest reserves famine, the imbalance between supply and demand of domestic paper industry fibrous raw material becomes increasingly conspicuous.First, fibrous raw material breach presents the gesture of expansion year by year; On the other hand, fibrous raw material proportion is unbalance, and wood pulp proportion is low ^[2].It is predicted, in the coming years, growth and the inharmonious situation of raw material supplying of China's paper and paperboard output also can be aggravated further.

In recent years, along with the development of extraordinary paper using and the raising that requires paper property, use proportion in paper-making process of non-fiber raw material got more and more, and wherein filler is more and more subject to people's attention due to its lower cost.Filler started for paper industry from 8th century of Christian era, over past especially 30 years, papermaking filler obtains significantly to be applied, add filler during copy paper and become an indispensable papermaking process, in the wet-forming processes of paper, papermaking filler consumption is the second largest class paper making raw material being only second to fiber.At present, papermaking filler is not only widely used in printing and writes in paper, and the application in wrapping paper, newsprint and tissue paper also expands gradually.According to estimates, often increase by 1% filler in paper, paper per ton can save 2.5 dollars ^[3].

According to different application occasion and the application conditions of filler, usual papermaking filler has some common basic nature effects.Such as, the most initial reason is exactly that the application of papermaking filler partly can replace wood pulp fibre, significantly can reduce cost of material; And while saving fibrous raw material uses, also serve the effect of protection of the environment and minimizing " carbon footprint " to a certain extent ^[4].In addition, paper adds many performances of filling out and also can improve paper product: 1. add the surface smoothness of filling out and can improve paper product, and thus paper can obtain good printing adaptability, whiteness and opacity.2. furthermore, add fill out can also improve paper DIMENSIONAL STABILITY, promote the outward appearance of paper product and class.3. by adding some modified fillers, also can give paper product some function affects, as antibiotic property, electric conductivity, magnetic etc. ^[4,5].

In recent years, improve and add one of the amount of filling out important development trend having become paper technology, enjoy the concern of papermaker.But filler is while playing above excellent properties, not only filler retention is lower for traditional embankment formula that adds, and can reduce fiber and fiber, adhesion between fiber and filler, adds the strength character of filling out paper thereupon and also can decline.Meanwhile, add to fill out and also can cause the series of problems such as sizing-trouble, paper machine burn into paper product hair and powder dropping.Therefore, tradition adds embankment formula and has certain limitation, and the ash content of paper is difficult to increase substantially.Therefore, under the prerequisite of not sacrificing paper performance, many research ideas are used to alleviate or eliminate above-mentioned defect ^[6-9].At present, both at home and abroad about under the prerequisite not affecting paper strength performance, improve filler retention and ash content research mainly contains stuffing surface modification technology, the pre-wadding of filler gathers technology, lumen/wall adds and to fill out and based on fiber/filler or fiber fines/filler complex technique etc.

In recent years, the filler coating modification technology based on natural polysaccharide receives much concern in field of papermaking ^[10-12], being considered to alleviate and adding one of effective way of filling out negative effect, is the research field of a great potential.Shitosan is similar with the structure of paper pulp fiber as natural polysaecharides material, can and fiber between produce good binding ability and compatibility, the coating modification using it for papermaking filler is practicable to improve the performances such as paper strength.

The present invention research object and meaning be: manufacture paper with pulp higher ash content and there is higher-strength paper condition under, the chitosan-coating modification technology of research filler and carry out high ash content add the application feasibility filled out in papermaking, thus provide certain basic research data and Data support for the development & application etc. adding the improvement of filling out paper performance, filler modified technology fills out paper at height.

2, domestic and international present Research

2.1 papermaking fillers and high filler paper present Research

Papermaking filler is divided into inorganic filler and organic filler two class, and inorganic filler has kaolin, calcium carbonate, talcum powder, titanium dioxide, aluminium hydroxide, calcium sulfate and amorphous silicate etc.; Organic filler has synthesis high score subclass, starch base filler, wood meal etc.Papermaking filler also can be divided into common micro-scaled filler and nano-sized filler according to the difference of size ^[4].At present, conventional papermaking filler is mainly micro inorganic fillers, and wherein the application of calcium carbonate, talcum powder and kaolin is the most general.Wherein talcum powder China rich reserves, fine quality, is one of maximum in the world talcum producing country.Talcum powder is a kind of trisimint, and its chemical formula is Mg ₃si ₄o ₁₀(OH) ₂.Paper grade (stock) talcum powder exists mainly with the form of flat crystal, has natural hydrophobicity and organic affinity.

Add the micro pigment or synthetic filling filling out in paper stock, add white mineral exactly, be used for improving the character of paper, the requirement meeting use better and saving paper pulp, reduce product cost ^[13].Usually, filling adding amount can account for the 20%-40% of paper stock component, and filler has become one of important component indispensable in modern paper, becomes the second largest component in the paper stock producing body paper.Improve the content of filler, can reduce costs on the one hand, the pollution to environment can be reduced on the other hand, can also give paper some special functions.

Production cost is reduced, in earlier U.S. Patents in order to increase mineral filler content ^[14]report and use the cationic polymer of the cationic starch of low charge density and high molecular synergy keeping for filler and tiny component, add a kind of novel cation synthetic polymer simultaneously and form a kind of retention dry strength agent system.This system is for the paper of the filer content > 15% that manufactures paper with pulp.In super mixer, 6 minutes are processed according to another the water slurry introduced with containing 30% china clay or pearl filler, add cationic starch or polyacrylamide after dilute with water, reprocessing 5 minutes, makes filler suspension, add again in slurry, be also suitable for producing high loaded sheet ^[15].Foreign latest describes the tencel shape filler of synthesis, and wood pulp fibre can be replaced to reach more than 50%, can greatly save fibrous raw material and producing cost ^[16].

The pre-wadding technology of gathering of papermaking filler be contribute to improve amount of filler and exploitation the high class important technology filling out paper, there is stronger industrial operability, height add fill out in there is significant application value.More also comparatively early about this type of research abroad, Cheng weiguo, Ross T etc. ^[17]have employed two step flocculation systems, first in fillers dispersed liquid, add the first flocculant, use the copolymer of acrylamide and sodium acrylate, now, the effect of first its induction of flocculation of flocculant, and the hierarchy of control does not form obvious flocculation; Then add the second flocculant (quaternary ammonium form) with opposite charges, filler grain and fibre stuff are combined, finally add reinforcing agent and form network structure.Domestic, Han Chen ^[18]adopt the poly-technical research of pre-the wadding preparation of the coated PCC of starch and the application in papermaking thereof.Result of study shows, cationic starch is a kind of well pretreating agent, and adds starch in common slurry and compares, and can significantly improve content of ashes and filler retention.But the problem of the poly-PCC dispersion of pre-wadding needs to solve further, produce large floc sedimentation to stop the poly-PCC of pre-wadding thus ensure high clad ratio.

Add the technology of filling out in fibrocyte, filler is filled in paper pulp fiber cell under certain condition, the contact of filler and fiber surface can be reduced while improving filer content, thus the adverse effect adding and fill out bond strength between fiber can be reduced.Add in cell to fill out and mainly contain cell lumen loading and flber loading.Haslam etc. point out, after filler and paper pulp fiber being mixed under certain condition, are more fully washed by the mixture of filler and paper pulp, observe and find that filler major part is attached in the lumen of fiber, successfully realize adding filling out.Middieton etc. point out, adopt the specific cationic water-soluble polymer pulp treatment suspension such as CPAM, after making it be adsorbed in the lumen of fiber, then by filler filler introducing system, can realize cell lumen loading under certain condition.

Filler modified technology also may be used for the application of high loaded sheet.Wang Huiping ^[19]etc. have studied modification cationic starch being used for pearl filler and the application of filling out at height in paper thereof, mention in literary composition, compare with the starch conversion calcium carbonate of calcium carbonate and same amount, cationic starch modified calcium carbonate significantly can improve paper strength; When the proportioning of cationic starch and calcium carbonate is 1:1, adding under the amount of filling out is the condition of 40%, the retention of modified calcium carbonate in paper adds than calcium carbonate that to fill out paper high by 86.0%.

2.2 filler modified Status of Researchs

2.2.1 based on the modification technology of inorganic compound class modifier

Inorganic compound can be widely used in the modification of papermaking filler, and its application significantly can improve acid resistance, the optical property and retention performance etc. of filler.Wherein studying more is the dissolution inhibition modification technology of pearl filler, and calcium carbonate has good stability in the alkaline environment of pH higher than 7.5, but dissolubility is stronger in acid system.Much research shows: hydrogen fluoride, calgon, phosphoric acid, calcium chloride, barium chloride, sodium metasilicate, dilute sulfuric acid and aluminum sulfate etc. can be used for the dissolution inhibition modification of calcium carbonate, make modified product have good stability in faintly acid and weakly acidic pH system.Domestic, Shen is waited quietly ^[20-22]comparatively systematic research has been carried out to the dissolution inhibition modification of calcium carbonate, relevant modifier comprises, phosphoric acid, phosphoric acid/calgon, phosphoric acid/sulfuric acid aluminium, phosphoric acid/aluminium chloride, sodium metasilicate/aluminium chloride, sodium metasilicate/phosphoric acid/calgon, calcium chloride/calgon etc.

For a long time, it is one of the important research content of wet end chemistry that filler is kept always, Zhang Haitao etc. ^[23]research shows, adopts Al ₂o ₃h ₂o and Al ₂o ₃h ₂o/P ₂o ₅when carrying out modification to talcum powder, the Surface coating of inorganic compound can make filler retention performance improve, when add fill out 30% time, filler retention increase by 29.76%.

In addition, the modification technology based on titanium class and zinc compounds also has research, can improve outward appearance and the optical property of paper product under certain condition, promotes class and the quality of paper product.

2.2.2 based on natural polysaecharides and the surface coated filler modified technology of derivative thereof

Conventional papermaking filler is inorganic filler, and they can not produce Hydrogenbond with paper pulp fiber usually, limited with the bond strength of fiber, and can disturb the combination between fiber.Meanwhile, the Size Distribution of filler grain can fill out generation material impact to adding.If by polymer overmold in filler grain surface, be just expected to increase filler and interfibrous binding ability to its modifying surface, reduce and highly add the negative effect of filling out; Natural polysaecharides and derivative itself thereof structurally have very large similarity with paper pulp fiber, containing a large amount of hydroxyl, amino etc. in molecule, good with the compatibility of fiber, therefore can consider the coating modification using it for filler.

As the coating modification material of filler, must possess following condition, (1) can be coated on filler grain surface by better simply method; (2) and wood pulp fibre compatibility good, can well combine the intensity improving paper; (3) not soluble under paper making wet part environment.At present, both at home and abroad research is all more with the research of starch and derivative thereof, and less about the research of shitosan, and has no the relevant report of modified talc powder of shitosan.Correlative study both domestic and external ^[24]show, general modified filler can produce two kinds of covered effects, and one is by coated for single filler grain, forms similar core/shell structure filler, and the second is by the aggregation of coated for multiple filler grain formation filler grain.

The signal of filler coating modification process can see Fig. 1.

2.2.2.1 based on the modification technology of starch and derivative thereof

(1) hard gel dry method modification technology

Basic modification thought starch is carried out under high solids content steaming work, then mixes with filler grain, form gel filler complex particle, then drying milled processed.Zhao etc. ^[25]starch is used to carry out modification to PCC, in its experimentation, (﹥ 45%) boiling under high solids content by starch and filler mixed liquor.First Powdered starch or modified starch are added in calcium carbonate suspension, mix; Filter and concentration suspension, then by mixture boiling 3h at 90 DEG C of filler and starch, now starch is swelling obtains partial cross-linked jello again; Finally by grinding and disperseing to obtain modified product.Result shows, the solubility of modified filler particle in paper stock system is not remarkable; Handmade paper experiment shows that starch modified stuffing significantly can improve the tensile strength of paper, also can improve the retention performance of filler.

Yan etc. ^[26]further improvement has been done to above-mentioned starch conversion route, the starch of boiling is in advance used for kaolinic coating modification, have studied the suspension of 30%60% different total solid content, Yan etc. find that the solubility of filler is less, compared with unmodified kaolin, it significantly can improve paper strength, and less on the impact of optical property; Modified filler is easily kept in interpolation polyacrylamide situation, and author points out, this kind of starch modified stuffing can be used for the application of high loaded sheet.

(2) wet-process modified thought

The modified filler that hard gel method obtains is not suitable for the in situ preparation of paper plant, so consider directly to process filler suspension, supending shape modified filler.First be intermediate processing is used for modification preparation, Yoon and Deng ^[27]adopt inorganic salts (NH4) ₂sO ₄for kaolin coating modification, first kaolin is joined in the unmodified starch suspension of 3%-4%, boiling is carried out to mixture, under agitation add 40% ammonium sulfate by the mixture after boiling again, separate out kaolin-composites of starch after continuing to stir a period of time, obtain modified filler after washing after filtration.When content of starch is higher, compounded mix size is comparatively large, can significantly improve the retention of filler and the strength character of paper.Domestic, Zhang Guanghua [28] etc. use starch/epoxychloropropane/ammonium sulfate coated to filler grain, can make clad in Aquo System, have better stability.

Yoon and Deng ^[29]further research is pointed out, Starch-lipid acid compound also can be used for modifying kaolin, and when adopting Starch-lipid acid compound to Modification of kaolin, modifier can effectively be coated on filler grain surface; In following dry run, starch can form film-form material through heating, and the formation of this starch film effectively can improve into the intensity of paper; The hydrophobicity of paper also can be made to improve adding of this modified filler in addition, be expected to the consumption reducing glue used in paper-making.Cao and Deng etc. ^[30]current research adjusts modifying process again, and fills out experimental study for adding of reuse OCC slurry.

Domestic, Shen is waited quietly ^[31]adopt starch/enuatrol/aluminum sulfate to CaCO ₃filler modified; Wang Huiping etc. ^[32]epoxychloropropane Cross-linking Cationic Starch is adopted to carry out coating modification experiment to GCC; Zhang Guanghua etc. ^[33]adopt starch conversion GCC, and introduce AKD, obtain a kind of water-tolerant, the much higher function AKD-starch of intensity-GCC compounded mix; Bai Wenrui etc. ^[34]utilize starch-stearic acid compound to add the method for crosslinking agent calgon to PCC modification, physical properties of paper and optical property are improved simultaneously.This type of filler modified technology based on starch shows to significantly improve the retention of filler and the strength character of paper.Article is not all mentioned unmodified filler and modified filler and is added the content of ashes change of filling out paper, therefore does not know that this modified filler adds and fill out the requirement whether paper reaches high filler paper.

2.2.2.2 based on the coating modification of cellulose or derivatives thereof

Nelson and Deng ^[35]prepare by being precipitated out from NMMO solvent by cellulose the nucleocapsid structure modified filler that a kind of cellulose is shell, the bond strength of modified filler and paper pulp fiber through test and fiberoptic fiber bond strength and starch-fiber bonding strength suitable.Adding with unmodified kaolin fills out compared with paper, and paper strength performance is significantly improved, and whiteness slightly reduces.

Under certain condition, CMC can form water-fast compound with some slaine, and Shen is waited quietly ^[36]research shows, adopts CMC/ aluminum sulfate to carry out modification to PCC filler under certain condition, and when the consumption of CMC and aluminum sulfate is respectively 4% and 12%, under the condition of not adding retention agent, filler retention can improve about 70%; And filler modified paper strength to be had no significant effect substantially.

2.2.2.3 based on the coating modification of chitin and derivative

Chitin and cellulose family seemingly, are also a kind of water-fast natural polymers.When being dissolved in some ionic liquids (as the chlorination of 1-normal-butyl-3-methylimidazole) by microwave, ultrasonic etc., after above-mentioned solution mixes with filler, adding non-solvent (as water or ethanol) again can make chitin be precipitated out, and forms surface coated modified filler.Use this new packing, optics and the strength character of filler retention, paper all have clear improvement, and therefore can save the use of paper pulp fiber and wet-end chemicals.Be applicable to the fillers such as titanium dioxide, kaolin and calcium carbonate based on cellulose or chitin overlay film modification technology, be expected to the production for high filler Paper or cardboard ^[24].

Shitosan is the product of chitin deacetylase base, has a series of excellent performance, as good biocompatibility, biodegradability and flocculability, is widely used in a lot of fields at present.Soane and Berg etc. ^[37]propose a kind of shitosan carries out modification method to pigment particles, author has carried out coated process to different filler grains, and result obtains higher filler retention and higher strength character.Shen is waited quietly ^[38]adopt intermediate processing shitosan to be used for the coating modification of PCC, during chitosan dosage 9%, tensile index improves 69%, and filler retention also makes moderate progress under certain condition.

Subramaniam Sabesan [39] etc. adopt Freeze Drying Technique, cm-chitosan are used for the coating modification of filler, are first at room temperature dissolved by cm-chitosan distilled water, then by TiO ₂be distributed in above-mentioned solution; After being heated to 60 DEG C again, freeze drying process is carried out to suspension, the TiO that cm-chitosan is coated can be obtained ₂particle.Patent is pointed out simultaneously, and the higher production that may be used for facing paper product kept by filler.

2.2.3 other modification technologies

Other modification technologies also extensively comprise pre-wadding poly-modification technology, polymer latex modified technology, surfactant-modified technology, silane coupler and aluminum-zirconium coupling agent modification technology.

Accompanying drawing explanation

Fig. 1 is Chitosan-coated modified talc powder and modified filler and fibration schematic diagram of mechanism.

Fig. 2-1 is chitosan dosage to the effect diagram of paper tensile index and burst index.

Fig. 2-2 is chitosan dosage effect diagram to greyness of paper.

Fig. 2-3 is mixing speeds to the effect diagram of overlay film amount and greyness of paper.

Fig. 2-4 is mixing speeds to the effect diagram of paper tensile index and burst index.

Fig. 2-5 is that reaction pH is to the effect diagram of talcum powder overlay film amount and greyness of paper.

Fig. 2-6 is that reaction pH is to the effect diagram of paper tensile index and burst index.

Fig. 2-7 is mixings time to the effect diagram of talcum powder overlay film amount and greyness of paper.

Fig. 2-8 is mixings time to the effect diagram of paper tensile index and burst index.

Fig. 2-9 is chitosan concentrations to the effect diagram of filler overlay film amount and greyness of paper.

Fig. 2-10 is chitosan concentrations to the effect diagram of paper tensile index and burst index.

Fig. 2-11 be before modified after talcum powder particle size distribution figure.

Fig. 2-12 is that rear talcous light microscope and FESEM scheme (talcous light microscope and SEM picture (A, B), the light microscope of modified talc powder and FESEM picture (C, D)) before modified.

Fig. 3-1 is the graph of a relation of Paper White Degree and greyness of paper amount.

Fig. 3-2 is graphs of a relation of paper opacity and greyness of paper amount.

Fig. 3-3 is graphs of a relation of paper tensile index and greyness of paper amount.

Fig. 3-4 is graphs of a relation of paper burst index and greyness of paper amount.

Fig. 3-5 adds the FESEM figure (talcum powder adds and fills out paper (A), and modified talc powder adds fills out paper (B), and modified talc powder adds to be filled out the test of paper tensile strength and break face (C)) filling out paper.

Detailed description of the invention

Below the embodiment of the present invention is elaborated.

2.1 fill out can reduce costs owing to adding, and improve the optical property of paper, can also reduce energy consumption simultaneously, improve paper machine operation etc. and widely used by papermaking enterprise.Meanwhile also create many problems, particularly high add the amount of filling out under, topmost problem is exactly the decline of paper strength, and filler retention is poor.Existingly adding the deficiency of filling out to overcome, reducing to add and filling out produced negative effect, stuffing surface modification research arises.

Shitosan has hydroxyl and amino structure, can form Hydrogenbond, carry out modification, can increase the adhesion between filler and fiber, improve paper performance with it to filling surface after becoming paper with paper pulp fiber.

Chitin modified talcous preparation technology is mainly studied in this part: investigate Viscosity of Chitosan, chitosan dosage, mixing speed, reaction pH, mixing time, each factor of speed of agitator to the impact of modified filler overlay film amount and serviceability, filters out and affects the key factor of shitosan to modified filler overlay film amount and serviceability; Adopt orthogonal test again, respectively with tensile index, burst index, whiteness, opacity and greyness of paper, filler retention is that index draws corresponding better reaction condition; And utilize particle size analyzer and ESEM to carry out test analysis to chitin modified talcum powder.

2.2 experiment

2.2.1 experimental raw

Table 2-1 tests main material

Research in the past shows, the kinds of fibers that production decorating base paper is used and the performance of fibre furnish to decorating base paper have material impact.When manufacturing paper with pulp decorating base paper, the slurry compositions that general use hardwood pulp coordinates with softwood pulp, to obtain the optimization of Performance and Cost Modeling, and high filler paper is a lot all applied in production facing paper, so the fibrous raw material that experiment uses is sulfate bleached hardwood pulp and sulfate bleaching needle-point leaf pulp mixed in equal amounts wood pulp.

Shitosan is three kinds of viscosity grades; be respectively high viscosity (viscosity=950cps; deacetylation degree is 85.7%; granularity is 100 orders), and medium viscosity (viscosity=202cps, deacetylation degree is 91.1%; granularity is 80 orders); low viscosity (viscosity=30cps, deacetylation degree is 92.1%, and granularity is 80 orders).Retention and drainage aid agent adopts cationic polyacrylamide (CPAM) and bentonite binary retention aid and filtering aid system.The molecular weight of CPAM is 800 ~ 1,000 ten thousand, and glacial acetic acid and NaOH are all made into acetum and the NaOH solution of 5wt%.

2.2.2 key instrument and equipment is tested

Table 2-2 major experimental instrument

2.3 experimental technique

2.3.1 the preparation of chitin modified filler

Under normal temperature, add a certain amount of talcs filler and distilled water in there-necked flask, fully stir and make it mix, wherein talcum powder quality accounts for 8% of mixed liquor quality; Be that the shitosan of 800cps adds in acetum by viscosity, and stir, make the chitosan-acetic acid solution that concentration is 6g/L; Joined by the chitosan-acetic acid solution newly prepared in above-mentioned filler suspension, continue high-speed stirred and make it fully mix, mixing speed is 700r/min, and mixing time is 60min, and chitosan-acetic acid solution quality accounts for 5% of total mixed solution quality; After certain hour, control mixing speed, the sodium hydroxide solution of 5% is slowly added drop-wise in above-mentioned suspension, makes the pH value of suspension be 10.Continue to stir certain hour, the chitosan molecule being adsorbed in filling surface is solidified, form the chitosan precipitation film that one deck is closely knit, modified filler suspension can be obtained.

Two kinds of modes are divided into the further process of modified filler: 1. filler suspension to be filtered, carrying out washing treatment, filter cake vacuumize at 50 DEG C, to over dry, then are carried out milled processed, obtains pulverulent filler, for papermaking; 2. after being washed by modified filler suspension, drying is not directly used for the manufacture of handmade paper with form of suspension.

2.3.2 the detection of modified filler and sign

(1) mensuration of modified filler covering amount: the muffle furnace calcination 4 hours modified filler being placed in 925 DEG C, calculates the overlay film amount of Chitosan-coated at filling surface.

Overlay film amount can calculate as follows:

$C=\frac{m_1-m_2/(1-\mathrm{\α})}{m_2/(1-\mathrm{\α})}\×100\%$

In formula: C-overlay film amount (%)

Modified filler quality (g) before m1-calcination

M2-calcination post-modification packing quality (g)

α-filler loss late (%)

(2) modified filler particle size determination: be decentralized medium with water, is aided with ultrasonic wave, utilizes Malvern 2000 laser particle analyzer to measure talcous particle diameter before modified.

(3) observation of modified filler exterior appearance: by sample after ion sputtering is gold-plated, adopts JSM-5610LV ESEM to take pictures to sample under 10KV voltage, observes the change of its configuration of surface.

2.3.3 page is manufactured paper with pulp

Bleached softwood wood and bleached hardwood pulp are taken slurry by 1:1 proportioning, discongests after mixing, handmade paper fiber basis weight 65g/m ²; After pulp dilution to about 2% concentration, add a certain amount of filler or modified filler (to over dry slurry); Paper-making process adopts cationic polyacrylamide (the CPAM)/bentonite (NaMMT) of 0.1% as double base retention Microparticle Retention System, first under 350r/min stirs, add first yuan of auxiliary agent, stir 30s, then under being adjusted to 750r/min, add second yuan of auxiliary agent, rapid copy paper after continuing to stir 30s.

2.3.4 the test of paper physical property

Page, after 24h equilibrium water conten, measures the whiteness of paper, opacity, tensile strength, bursting strength and ash content according to national standard method.

(1) mensuration of Paper White Degree and opacity

Whiteness instrument is used to measure whiteness and the opacity of paper.

(2) mensuration of paper tensile strength

Tensile strength refers to the maximum tension that paper bears, the tension force born when referring to the sample fracture of one fixed width.The mensuration of tensile strength is see GB/T 4531989.

Tensile index is calculated as follows:

$Y=\frac{\stackrel{-}{F}}{L_W\×g}\×{10}^3$

In formula: Y-tensile index (Nm/g)

Quantitative (the g/m of g-sample ²)

-average tensile power (N)

L _wthe width (mm) of-sample

(3) mensuration of paper bursting strength

The mensuration of bursting strength is see GB/T 454-1989.

Paper burst index can be calculated as follows:

$X=\frac{P}{g}$

In formula: X-burst index (kPam ²/ g)

P-definitely bursting strength (kPa)

G-quantitatively (g/m ²)

(4) mensuration of greyness of paper

Ash content refers to sample at high temperature through charing and calcination, and remaining mass of residue and the ratio of sample mass, be expressed as a percentage.Greyness of paper is calculated by following formula:

$X=\frac{m_1-m_2}{m}\×100\%$

In formula: X-ash content of paper (%)

M ₁in crucible after-calcination (g)

M ₂the crucible heavy (g) of lime-ash is filled after-calcination

M-over dry sample heavy (g)

2.4 results and discussion

2.4.1 Viscosity of Chitosan is on the impact of talcum powder modification

Modified-reaction condition is: Viscosity of Chitosan be low (30cps), in (202cps) and high (950cps), chitosan dosage is 5% of talcum powder quality, and mixing speed is 500r/min, mixing time is 40min, chitosan concentration is 5g/L, and reaction pH is 8, and temperature is room temperature.Viscosity of Chitosan on talcum powder overlay film amount and add fill out modified talc powder paper tensile index, burst index and ash content impact in table 23.

Table 2-3 Viscosity of Chitosan is on the impact of talcum powder modification

As can be seen from table 2-3, for the shitosan of different viscosities type, clad ratio is all higher, substantially can completely with the coated filler grain of the form of deposited film, and along with the increase of viscosity, covering amount also slightly improves.The anti-tensile of paper and burst index increase along with viscosity and improve, this is mainly because viscosity increases, chitosan molecule quantitative change is high, chain length can be longer, can better be wrapped in around filler grain and surface, form more hydrogen bond between meeting and fiber after copy paper, the combination of filler and fiber can be improved, thus improve paper strength performance.So select high viscosity comparatively suitable.

2.4.2 chitosan dosage is on the impact of talcum powder modification

Modified-reaction condition is: chitosan dosage is the 1%-9% of talcum powder quality, and Viscosity of Chitosan is high viscosity (950cps), and mixing speed is 500r/min, and mixing time is 40min, and chitosan concentration is 5g/L, and reaction pH is 8, and temperature is room temperature.Chitosan dosage is shown in shown in Fig. 2-1, Fig. 2-2 adding the impact of filling out modified talc powder paper tensile index, burst index and ash content.

By the increase along with chitosan dosage in Fig. 2-1, Fig. 2-2, add the tensile index of filling out paper and burst index also constantly increases, mainly due to after chitosan molecule is coated on filling surface, the contact area of filler and fiber can be reduced, and its strand contains abundant hydroxyl and amino, filler and interfibrous combination can be improved.Can find out that ash content does not have significant change by ash amount change curve, reach maximum when consumption 7%, ash content reaches the requirement of high ash content 30% simultaneously.

Therefore, chitin modified can keep high-ash while, can effectively improve the intensity adding and fill out paper, but consider, use too much shitosan to increase cost, select chitosan dosage be 7%.

2.4.3 mixing speed is on the impact of talcum powder modification

Modified-reaction condition is: mixing speed is 300-1100r/min, and Viscosity of Chitosan is high viscosity (950cps), and chitosan dosage is 7% of talcum powder quality, and mixing time is 40min, and chitosan concentration is 5g/L, and reaction pH is 8, and temperature is room temperature.Mixing speed fills out modified filler paper tensile index, burst index to talcum powder modifying process with adding, and ash content impact is shown in shown in Fig. 2-3, Fig. 2-4.

As can be seen from Fig. 2-3, Fig. 2-4, no matter mixing speed is the overlay film amount to modified filler, or on add fill out rear paper strength character, ash amount impact all more remarkable.Overlay film amount presents the rear downward trend of first increase along with the increase of rotating speed, reaches maximum when 500r/min.Add the tensile index filling out paper and also have similar variation tendency with ash content, because coated process is the process of a physical absorption, the impact of liquid body diffusion velocity and shearing force is larger, when stir in a certain degree scope strengthen gradually time, make the precipitation of shitosan more even, thickness of diffusion layer reduces, and mass transfer is fast, can make shitosan evenly be adsorbed on filler grain surface; But when mixing speed is crossed strong, can make coated on shitosan come off, thus affect covered effect.Consider, mixing speed is comparatively suitable at 500r/min.

2.4.4pH on the impact of talcum powder modification

Modified condition is: reaction pH is 6-14, and Viscosity of Chitosan is high viscosity (950cps), and chitosan dosage is 7% of talcum powder quality, and mixing speed is 500r/min, and mixing time is 40min, and chitosan concentration is 5g/L, and temperature is room temperature.Reaction pH fills out modified talc powder paper tensile index, burst index to adding, and the impact of ash content and modified filler overlay film amount, the results are shown in Figure shown in 2-5, Fig. 2-6.

As can be seen from Fig. 2-5, Fig. 2-6, when reaction pH is 6, the overlay film amount of filler, the content of ashes of paper is all very low, and tensile index and burst index are all higher, this is mainly because shitosan still has certain dissolubility under mildly acidic conditions, shitosan can not be precipitated out completely, also can not be coated on talcum powder surface and form deposited film, thus have impact on the combination between modified talc powder and fiber, cause filler retention low, so tensile index and burst index are all higher.After precipitation pH reaches alkalescence, variation tendency is not clearly, and the best results presented when pH is 8-10.Consider, select reaction pH=8 comparatively suitable.

2.4.5 mixing time is on the impact of talcum powder modification

Modified-reaction condition is: mixing time is 5min-100min, and Viscosity of Chitosan is high viscosity (950cps), and chitosan dosage is 7% of talcum powder quality, and mixing speed is 500r/min, and chitosan concentration is 5g/L, and reaction pH is 8, and temperature is room temperature.Mixing time is to modified talc powder overlay film amount and add tensile index, the burst index of filling out modified filler paper, and ash content impact is shown in shown in Fig. 2-7, Fig. 2-8.

As can be seen from Fig. 2-7, Fig. 2-8, the tensile index of paper, burst index, content of ashes and talcous shitosan overlay film amount are all along with the increase of mixing time first raises rear decline, all maximum is reached when mixing time is 20min, this is because when mixing time is shorter, fillers dispersed effect is bad, affects the even formation of chitosan precipitation film; Along with the increase of mixing time, fillers dispersed is more even, shitosan overlay film amount also progressively increases, but the long shitosan coating layer being originally deposited in talcum powder surface that also can make of mixing time comes off, thus affects the combination between talcum powder and fiber.Consider, select best mixing time to be 20min.

2.4.6 chitosan concentration is on the impact of talcum powder modification

Modified-reaction condition is: Viscosity of Chitosan is high viscosity (950cps), and chitosan dosage is 7% of talcum powder quality, and mixing speed is 500r/min, and mixing time is 20min, and chitosan concentration is 5g/L, and reaction pH is 8, and temperature is room temperature.Mixing time is to talcum powder overlay film amount and add and fill out modified talc powder paper tensile index, burst index, and the impact of ash content, it the results are shown in Figure shown in 2-9, Fig. 2-10.

As can be seen from Fig. 2-9, Fig. 2-10, modified filler overlay film amount first improves rear reduction along with the increase of chitosan concentration, and overlay film amount is the highest when 3g/L.Modified filler is added after filling out, paper performance and calcination ash amount also along with chitosan concentration first increases rear reduction, but with overlay film amount unlike, it reaches the highest when concentration 5g/L.Because when chitosan concentration is too high, shitosan compares thickness with the suspension of filler, and the shearing force be subject to is uneven, and shitosan can not be made to separate out uniformly, thus makes filler aggregation not formed well time main; And during high concentration, the chitosan layer of precipitation may be thicker softer, easily comes off from filler grain surface.Considering, for reaching the target of high filler, selecting most suitable chitosan concentration to be 5g/L.

2.4.7 the optimization of chitin modified talcum powder preparation technology

By above-mentioned single factor experiment, tentatively can show that the factor larger to chitin modified talcum powder process influence is, Viscosity of Chitosan, chitosan dosage, pH value in reaction and chitosan concentration.According to single factor experiment result, further selected above-mentioned four variablees, the orthogonal experiment L9(43 by four factor three levels) (see table 2-4) determine the preparation process condition of modified talc powder, experimental result is in Table 2-5.

Table 2-4 empirical factor factor level

Table 2-5 orthogonal design and experimental result

The range analysis of table 2-6 whiteness index

The range analysis of table 2-7 tensile index index

The range analysis of table 2-8 burst index index

The range analysis of table 2-9 ash content index

The range analysis of table 2-10 filler retention index

The range analysis of table 2-11 filler overlay film figureofmerit

From the experimental result of table 2-5 and the range analysis of table 2-6 to table 2-11, the tensile index of Viscosity of Chitosan to paper has the greatest impact, this is because the viscosity size of shitosan is relevant with chitosan molecule amount, the chitosan molecule chain length of macromolecule, there is in molecular structure more hydroxyl and amino, with the more Hydrogenbond of processbearing astrocyte can improve the combination between filler and paper pulp fiber, thus improve paper tensile index.Chitosan dosage is all maximum on the impact of the burst index of paper, whiteness and shitosan overlay film amount, this is because the consumption of shitosan is more, the amount being coated on talcum powder surface is more, and overlay film amount is just corresponding improve also.Coated shitosan is more, and the combination of modified filler and paper pulp fiber is better, and burst index also just improves more; Meanwhile, because shitosan whiteness is lower than talcum powder, the consumption of shitosan is many, and Paper White Degree is lower.Ash content is that height adds the important performance filling out paper, can find out that the impact of Viscosity of Chitosan on ash content is larger from table 2-9, as can be seen from table 2-10 also, Viscosity of Chitosan is very large on filler retention impact, this may be because full-bodied shitosan can increase the granularity of modified talc powder, make the Zeta potential of modified filler increase simultaneously, thus increase filler keeping in page.The impact that other factors are prepared modified talc powder is compared all smaller time between concentration 4g/L to the 6g/L of shitosan.

From the experimental result of table 2-5 and the range analysis of table 2-6 to table 2-11, in use high-viscosity chitosan, chitosan dosage is 7%, chitosan concentration is 5g/L, it is relatively better that the modified talc powder that reaction pH obtains when being 10 adds the strength character of filling out paper, and overlay film amount, ash content and filler retention are higher.Consider the commercial viability of price to this technology of shitosan, and when chitosan dosage is 5% and 7%, the difference of each index is little, consider therefore finally determine that preferred process condition prepared by chitin modified talcum powder is: Viscosity of Chitosan is high viscosity, chitosan dosage is 5% of talcum powder quality, chitosan concentration is 5g/L, and reaction pH is 10.

2.4.8 chitin modified talcous particle size distribution measures

Before modified, talcum particles granularity is shown in Fig. 2-11.As can be seen from Fig. 2-11, unmodified talcum powder average grain diameter mainly concentrates on about 10 μm, and modified packing material size enlarges markedly, and granularity is mainly distributed near 45-50 μm.Mainly by several filler grain voluble wrapping together, filler form there occurs change to shitosan, defines larger filler aggregation.This larger filler aggregation, contributes to filler keeping in page, and the shitosan of filling surface can with processbearing astrocyte Hydrogenbond, be of value to and improve the intensity of paper.

2.4.9 chitin modified talcous morphological analysis

, product is observed with SEM talcous coated situation to be well understood to starch in modified talc powder filler.Before modified, the change of filler microscopic appearance as shown in figs. 2-12.Can find out in composition graphs, modified filler and unmodified filler exterior appearance have notable difference, and unmodified filler is single sheet crystal structure (A figure), and as can be seen from microphotograph, modified filling surface is coated with the lighttight chitosan film of one deck; After chitin modified, filler grain becomes large, thickness obviously increases.Multiple particle is coated togather the larger-size filler grain aggregation defining and be similar to sandwich construction by shitosan, can reduce the bonded area between filler grain and paper pulp fiber like this, be conducive to improving filler and keep and the strength character becoming paper.

2.5 this chapter mainly study chitin modified talcous preparation technology, and characterize modified talc powder, draw:

(1) according to monofactorial experimental result, select talcum powder serviceability four larger factors of impact and factor level, design the orthogonal test of four factor three levels, the result of orthogonal test shows: be high viscosity at Viscosity of Chitosan, chitosan dosage is 5% of talcum powder quality, and chitosan concentration is 5g/L, and it is relatively better that the modified talc powder obtained when reaction pH is 10 adds the strength character of filling out paper, whiteness is higher, and overlay film amount, ash content and filler retention are higher.

(2) granularmetric analysis proves that modified talcous particle obviously increases than unmodified talcum particles particle diameter, ESEM proves that before modified, talcum powder configuration of surface and granularity have had obvious change, all show that shitosan successfully defines one deck chitosan precipitation film on talcum powder surface.3 chitin modified talcum powder are on the impact of paper performance and paper stock wet-end characteristic

3.1 this part mainly have studied the impact on paper optical property and strength character under difference adds the amount of filling out of shitosan modified talc powder and unmodified talcum powder under different viscosities (high viscosity=950cps, medium viscosity=202cps, low viscosity=30cps); And further study under difference adds the amount of filling out, paper stock is dynamically kept and water filtering performance.

3.3.1 modified filler adds the impact of filling out paper optical property

The modified talc powder of different viscosities shitosan (high viscosity=950cps, medium viscosity=202cps, low viscosity=30cps) and unmodified talcum powder different add the amount of filling out under Fig. 3-1 and Fig. 3-2 is shown on the impact of Paper White Degree and opacity.

As can be seen from table 3-1, Fig. 3-1, different Viscosity of Chitosan modified talc powder and unmodified talcum powder all with the increase adding the amount of filling out, the whiteness of paper increases.But identical add the amount of filling out under, add the Paper White Degree filling out modified talc powder and comparatively add and fill out unmodified talcous Paper White Degree and decrease, in modified filler, the Paper White Degree of the modified talc powder that Viscosity of Chitosan is high is higher.This is because compared with talcum powder, the whiteness of shitosan is relatively low, and when it is coated on talcum powder particle surface with the form of deposited film, the whiteness of filler declines to some extent.Experimental result shows, the talcum powder after chitin modified is unhelpful to the whiteness improving paper, but impact is little.

As can be seen from table 3-2, Fig. 3-2, the modified talc powder of different Viscosity of Chitosan and unmodified talcum powder are all with the increase adding the amount of filling out, and the opacity of paper increases thereupon.Identical add the amount of filling out under, adds the paper opacity of filling out modified talc powder and comparatively add that to fill out unmodified talcous paper opacity high, and the paper opacity of the higher modified talc powder of Viscosity of Chitosan is higher.Experimental result shows, the talcum powder after chitin modified is conducive to the opacity improving paper.

3.3.2 modified filler adds the impact of filling out paper strength performance

Modified talc powder and unmodified talcum powder different add the amount of filling out under Fig. 3-3, Fig. 3-4 are shown on the impact of paper tensile index and burst index.

As can be seen from Fig. 3-3, Fig. 3-4, unmodified talcum powder is along with the increase adding the amount of filling out, and tensile index, the burst index of paper decline gradually.Identical add the amount of filling out under, add the paper ratio filling out modified talc powder and add and fill out unmodified talcous paper, its tensile index, burst index are significantly improved, and Viscosity of Chitosan is higher, and it is better that modified talc powder adds every intensity index of filling out paper.When ash amount is increased to 37% from 20%, high-viscosity chitosan modified talc powder adds to be filled out paper tensile index and is reduced to 16.4Nm/g from 24.6Nm/g; Compared with unmodified talcum powder, above-mentioned tensile index adds 15% and 64% respectively.At typical condition, bond strength between fiber and contact area determine the intensity of paper, after adding unmodified talcum powder, because it can not form effective combination with fiber surface, this just hinders the combination between fiber and fiber, will certainly produce certain impact to the strength character of paper; And filler retains more in page, it is larger to paper strength characteristics influence.When by Chitosan-coated behind talcum powder surface, because its solubility in water reduces, be not easily destroyed under copy paper condition; When add fill out modified talc powder time, because chitosan molecule is rich in hydroxyl and amino, paper can form Hydrogenbond between modified filler and paper pulp fiber after drying, can strengthen the intensity adding and fill out talcum powder paper.Also can find out from figure, under identical intensity index, add the paper filling out modified talc powder and can significantly improve and add the amount of filling out, this makes to add fills out the reduction production cost that modified talc powder can be potential.The combination schematic diagram of modified filler and paper pulp fiber is see Fig. 1.

3.3.3 modified filler is dynamically kept paper stock and the impact of water filtering performance

Fig. 2-12 high-viscosity chitosan modified talc powder is kept paper stock and the impact of water filtering performance

Note: add the amount of filling out for relative dry paper fiber.

As can be seen from the table, when adding the amount of filling out and being 30%, modified filler retention can up to 90%, and unmodified filler retention is lower than 80%.When adding the amount of filling out and reaching 70%, modified filler retention ratio is that modified filler is high by 86.5%.So, the filler modified improvement that can promote retention to a certain extent, becomes relevant greatly with the particle diameter of modified filler on the one hand, on the other hand after the coated upper shitosan of filling surface, can reduce the negative electrical charge of filling surface, Zeta is more tending towards on the occasion of thus is conducive to filler keeping.

3.3.4 add the FESEM filling out paper to observe

See Fig. 3-5, its be add fill out paper FESEM figure: talcum powder adds fills out paper (A), and modified talc powder adds fills out paper (B), modified talc powder add fill out paper tensile strength test break face (C).

The impact on paper optical property and strength character of under different ash amount modified talc powder and unmodified talcum powder is mainly studied in 3.4 this part.Draw: along with paper adds the increase of the amount of filling out, Paper White Degree and opacity increase, and tensile index and burst index all decline.Under identical ash amount, add fill out compared with paper with unmodified talcum powder, add that the Paper White Degree filling out modified talc powder is lower slightly, opacity raises to some extent, tensile index and burst index have and comparatively significantly improve.When ash amount is 37%, compared with unmodified talcum powder, high-viscosity chitosan modified talc powder adds to be filled out paper tensile index and improves 64%, and meanwhile optical property is not significantly affected.

Chitin modified filler can significantly improve filler retention, and through dynamically keeping test, when adding the amount of filling out and being 30%, modified filler retention reaches 90%, and unmodified talcum powder is lower than 80%.When adding the amount of filling out and being increased to 70%, modified filler retention is still high than unmodified filler by 39%, now always keeps also better.

Add the SEM test of filling out paper to show, modified filler can be combined preferably with processbearing astrocyte, is conducive to the strength character improving into paper.

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Claims (7)

1. a preparation method for chitin modified talcum powder papermaking filler, is characterized in that as follows:

1) talcum powder and water mixed and stir, being mixed with mixed liquor, wherein, talcum powder quality accounts for 5 ~ 15% of mixed liquor quality;

2) be that the shitosan of 800cps adds in acetum by viscosity, and stir, make the chitosan-acetic acid solution that concentration is 6g/L;

3) mixed by the chitosan-acetic acid solution of the mixed liquor of the 1st step with the 2nd step, stir 5 ~ 100min with the speed of 300 ~ 1100r/min, wherein, chitosan-acetic acid solution quality accounts for 1 ~ 11% of mixed solution gross mass;

4) continue the mixed solution of stirring the 3rd step, and be slowly added dropwise to the sodium hydroxide solution that mass fraction is 5%, pH value to 6 ~ 14 of regulator solution;

5) continue the solution of stirring the 4th step, the chitosan molecule being adsorbed in filling surface is solidified, form the chitosan precipitation film that one deck is closely knit, namely obtain modified filler suspension.

2. the preparation method of chitin modified talcum powder papermaking filler as claimed in claim 1, is characterized in that: in the 1st step, talcum powder quality accounts for 8% of mixed liquor quality.

3. the preparation method of chitin modified talcum powder papermaking filler as claimed in claim 1, it is characterized in that: in the 3rd step, chitosan-acetic acid solution quality accounts for 8% of total mixed solution quality, and mixing speed is 700r/min, and mixing time is 60min.

4. the preparation method of chitin modified talcum powder papermaking filler as claimed in claim 1, is characterized in that: in the 4th step, and the pH value regulating mixed liquor is 10.

5. the preparation method of the chitin modified talcum powder papermaking filler as described in any one of claim 1-4, is characterized in that: the 1st step and the 2nd step are exchanged.

6. an application for chitin modified talcum powder papermaking filler, is characterized in that: after being washed by the modified filler suspension obtained by claim 1-5, be directly used for papermaking with form of suspension.

7. an application for chitin modified talcum powder papermaking filler, is characterized in that: carried out filtering, washing by the modified filler suspension obtained by claim 1-5, obtain filter cake, by filter cake vacuumize at 50 DEG C, grind again, obtain pulverulent filler, for papermaking.