Background technology
The development of acetate fiber has last 100 years history, invented with since the industrialization of cotton pulp dregs of rice production acetate fiber from GA age Englishman, because acetate fiber production is narrow more good more to the degree of polymerization distribution requirement of cotton linter, and cotton linter is because growth cycle is short, the degree of polymerization distribution broad and the degree of polymerization are not high, thereby to its cotton linter quality requirement height, and owing to adopt the conventional high-temperature autoclaving with the impurity of removing cotton linter and the secondary wall that destroys fiber, primary wall etc., cause fiber acutely to be degraded, cause the degree of polymerization sharply to descend, so produce the special-purpose pulp of acetate fiber with cotton linter, narrow to the cotton linter range of choice, the production cost height, complex process, cause whole acetate fiber slower development, to the sixties in last century, after the American invents and is the raw material production acetate fiber with timber, the sector is just comparatively fast developed, the existing whole world most of acetate fiber producer all adopts wood pulps to prepare acetate fiber, and it is to be raw material with the cotton linter that the high-quality acetate fiber product of minority 1-2 family manufacturer production is only arranged.
China produces cotton big country, has abundant cotton linter raw material, and the cotton linter raw material output is at the forefront in the world, and cotton linter belongs to the by-product in the cotton production processing, only is the raw material as viscose glue and papermaking to a certain extent, and the value of itself does not find full expression.And the needlebush that China be timber resources deficient state, particularly acetate fiber uses is more nervous, and it is narrow to prepare degree of polymerization distribution, and the degree of polymerization, the cotton pulp dregs of rice that alpha-cellulose content is high are used for acetate fiber production, have important practical significance.
Existing cotton linter is produced cotton pulp for acetate fibre, all take the batch production of traditional high temperature, high pressure, high alkali charge, the product lack of homogeneity of producing, to cotton linter quality requirement height, and environmental protection is difficult to up to standard, cause the product cost height, very easily be subjected to the restriction of short cashmere quality, be difficult to large-scale production.The prior art defective mainly shows the following aspects:
One, aspect pre-preg: adopt the preimpregnation squeezer, extremely inhomogeneous to the cooking liquor dipping of cotton linter, cause the infiltration of digestion process herb liquid uneven, react inhomogeneous, the uniformity of boiling is brought very big influence.
Two, aspect boiling: adopt high temperature, high pressure, high alkali charge boiling, because cotton linter fiber is longer, easily " conglomeration of making a rope by twisting the strands together ", adopt the rotary spherical digester boiling mostly, when the rotary spherical digester boiling, cotton linter easily produces relative motion with the boiling of rotating, can not mix, influence the uniformity of product.
Three, aspect washing and screening: adopt the decker of low concentration etc., the water consumption height, no screening installation can't be removed non-plant fibre class impurity.
Four, aspect making beating: adopt trough-style pulp beater and big tapering jordan, fiber is cut off, have shortcomings such as energy consumption height, work efficiency is low, noise is big.
Five, according to above elaboration, prior art is finished by corresponding apparatus from being dipped into each operation of making beating in advance, and link is more, is that investment, plant maintenance, technology monitoring, quality management all exist drawback with respect to single equipment.
Six, double-screw pulp-milling (be also referred to as double helix and two roller fiberizers), this machine is former to be to be used for the special equipment that plastics are extruded, and utilizes this know-why producd fibers pulp, in cotton pulp dregs of rice industry and viscose glue industry beyond example still.The present invention utilizes its technology, theory of mechanics, the reality that binding fiber is produced, particularly the grouping (segmentation) that aligns the backpitch district at the production characteristics of fiber pulp is redistributed, make it to make high-quality cotton pulp for acetate fibre, can economize on water again, economize on electricity, reduce wearing and tearing equipment.
Summary of the invention
The present invention is intended at the above many drawbacks that exist on the method for producing cotton pulp for acetate fibre, a kind of production method of cotton pulp for acetate fibre is provided, the present invention especially solves the problem that boiling and pulping process exist in the cotton pulp dregs of rice preparation process, the cotton pulp dregs of rice that provide have good uniformity, low, the high and low pollution characteristics of effect of energy consumption, make the cotton linter acetate fiber of being produced to reach the product that is better than GB, and the degree of polymerization can control arbitrarily in DP 800-2000 scope.
For achieving the above object, the technical solution used in the present invention is as follows:
Method for producing cotton pulp for acetate fibre, step comprises that opener, washing, soup mix, pull an oar and manufacture paper with pulp, it is characterized in that: cotton linter is sent into double-screw pulp-milling behind the opener, subsection water injection and injection liquid in double-screw pulp-milling, in double-screw pulp-milling, finish washing, soup mixing and pulping process, form slurry.
The beneficial effect that adopts the present invention to prepare cotton pulp for acetate fibre mainly shows:
One, existing cotton linter adopts the preimpregnation squeezer, the cotton linter cooking liquor is pushed mixing, the preimpregnation squeezer is actually for having single-screw (or double helix) conveyer in certain displacement (pitch) or reducing (spiral shell footpath), only depend on low speed rotation and lower compression to become (general<1: 1.5), cotton linter and cooking liquor are mixed and certain extruding, to reach the requirement that mixes.Because during boiling, the initial concentration of cooking liquor ratio and cooking liquor can not be too big and low excessively, and the volume of soup can not be excessive, and cotton linter unit weight little (quality that is unit volume is little), the soup that adds can not spread in cotton linter rapidly, so cause mixing inhomogeneous.
Adopt double-screw pulp-milling, because it has high compression ratio (1: 10-20) and higher rotation speed (300-500 rev/min), cotton linter can be compressed rapidly, and with higher liquor strength cotton linter is fully being mixed under the rotation at a high speed, mix to reach, have low liquor ratio in the time of can guaranteeing to satisfy boiling again;
When two, now using pulp with pulp and viscose glue with pulp and other cellulose derivatives with cotton linter production acetate fiber, all being first boilings, pulls an oar in the back.Before making beating, because cotton linter fiber is long, cause the slurry difficulty of transportation, be difficult to realize take " spurting " and higher concentration to carry to the boiling disposed slurry; All adopt " batch turning under the ball " and low concentration to carry, only after finishing making beating, just can under higher concentration, carry.
Adopt double-screw pulp-milling, cotton linter can be finished mixing in a machinery, working procedures such as cut staple need not follow-up making beating to fibre cutting.Only, can greatly reduce the making beating power consumption because it is the cut-out of finishing fiber at the dense state of height.
Simultaneously, under the dense state of height, fiber is pulled an oar, can rely on interfibrous mutual friction, rub, can destroy the primary wall and the secondary wall of most of fiber, help the infiltration of cooking liquor, reduce soup consumption.The reactivity (reactivity worth) of more useful raising finished product pulp provides good quality assurance for the downstream produces.
Three, this invention has the flow process weak point, takes up an area of and lack.Slurry is finished conveying, boiling, bleaching, washing under the high concentration state, can greatly reduce water consumption
To sum up, the present invention has that flow process is short, the production kind is flexible, with short production cycle, can not need boiling can produce high-quality cotton pulp for acetate fibre, particularly producing high whiteness (being whiteness 〉=90%), high polymerization degree (DP=1500-2500), during high-purity (alpha-cellulose 〉=99%), it is to be difficult to reach even can't make such product that tradition relies on high temperature, high pressure, high alkaline boiling.The present invention has of many uses, not only can produce the above-mentioned acetate fiber pulp of preparation, can also be widely used in produce the preparation viscose with the cotton pulp dregs of rice, nitrocellulose with the cotton pulp dregs of rice and cellulose derivative fibres element ethers with products such as purified cottons.
The specific embodiment
What the present invention proposed is a kind of method for producing cotton pulp for acetate fibre, step comprises that opener, washing, soup mix, pull an oar and manufacture paper with pulp, cotton linter is sent into double-screw pulp-milling behind the opener, subsection water injection and injection liquid in double-screw pulp-milling, in double-screw pulp-milling, finish washing, soup mixing and pulping process, form slurry.
The double-screw pulp-milling that the present invention utilized is also referred to as double helix and two roller fiberizers, and this machine is former to be to be used for the special equipment that plastics are extruded, and in the present invention it be used to fiber wash, soup mixes, making beating, has substituted many groups equipment of traditional handicraft.The used double-screw pulp-milling of the present invention is owing to belong to prior art in the plastics field of extruding, so its concrete structure is no longer too much given unnecessary details.
Described double-screw pulp-milling has at least a washing room and a soup to mix workshop section, and in general washing room can be arranged to two sections, and leading portion soaks into the back segment washing, does not get rid of the washing room that adopts more than three sections.Washing room is preceding, soup mix workshop section after, the screw rod of each workshop section has right-handed screw district and backpitch district, the medicine-pouring port that the water filling port of washing room and soup mix workshop section is located at the right-handed screw district of workshop section separately, pulping process mixes workshop section through whole washing and soup, be that fiber enters double-screw pulp-milling and just begins to carry out making beating work, the washing in double-screw pulp-milling, soup mix, making beating is referred to as pulping process.
In the double-screw pulp-milling running, there are extruding and friction between the fiber of cotton linter, produce the reaction of certain heat after thus temperature conditions is provided for dosing; Mix workshop section at soup, after soup mixes, add to have uniform temperature this moment, can carry out initial action, this initial action also can be regarded as boiling.Institute adds soup and can add different soups according to the different process requirement, and this belongs to general knowledge known in this field.Slurry forms and discharges after the double-screw pulp-milling, has following three kinds of technical process at least according to different technology conditions and technological requirement:
Embodiment 1:
When producing the high polymerization degree product, when promptly DP is 1500-2500;
Slurry washs, desanding, the operation of manufacturing paper with pulp after double-screw pulp-milling is discharged.Its technical process is:
In being transported to the double-screw pulp-milling process, add water-wet behind A, the cotton linter opener, and in course of conveying, measure;
B, the cotton linter after wetting enter double-screw pulp-milling, add entry once more before this machine right-handed screw the last period, and cotton linter is washed, and in the extruding of backpitch district and by the filter plate draining, add water at two sections and wash; In aforementioned two sections, cotton linter is extruded, rubs and is cut off, and control slurry mass dryness fraction, adds soup in the 3rd section, and mixes with cotton linter rapidly, cuts off once more, and controls out the slip mass dryness fraction;
After C, the slurry after mixing were sent by discharging opening, it was temporary and continue reaction to enter feed bin;
D, reaction are washed after finishing, desanding, the operation of manufacturing paper with pulp.
Its process conditions are as follows:
The moisture content that enters the cotton linter of double-screw pulp-milling is: 70-30%;
Adding the water yield at one, two section is 3-8m
3/ ton short flannel adds water pressurization 0.5-1.2Mpa; Add soup in the 3rd workshop section, soup adds pressure: 0.5-1.2Mpa, and institute adds soup and is:
NaOH (NaOH juice): 2-18% (to over dry cotton linter weight ratio)
Sodium sulfite or ammonium sulfite: 0.1-10% (to over dry cotton linter weight ratio)
H
2O
2(folding 100%): 2-15% (to over dry cotton linter weight ratio)
Waterglass (sodium metasilicate): 0.5-7.0% (to over dry cotton linter weight ratio)
EDTD (DTPA): 0.1-3.0% (to over dry cotton linter weight ratio)
Magnesium sulfate (MgSO
4): 0.5-6.0% (to over dry cotton linter weight ratio);
Discharging concentration: 20-45%, temperature: 85-95 ℃, go out first double-screw pulp-milling fibre length: the 3-4mm,
Enter feed bin temperature: 85-95 ℃, at feed bin reaction time: 1-5h;
Feed bin disposed slurry QUALITY STANDARD in the above-mentioned pulping process:
Whiteness: 75-90%, alpha-cellulose: 95.0-99.0%, yield: 70-90%, the degree of polymerization: DP=1500-2500, ash content: 0.10-0.20%, iron: 20-100ppm, R10:95-99.5%, S18≤0.5%.
Embodiment 2:
Aborning during the high polymerization degree product, promptly during DP:1000-1500;
Slurry is temporary in feed bin or directly enters second group of double-screw pulp-milling after double-screw pulp-milling is discharged, carry out the washing in double-screw pulp-milling for the second time, soup mixing, pulping process, discharge from double-screw pulp-milling then, wash, desanding, the operation of manufacturing paper with pulp.Its technical process is:
In being transported to the double-screw pulp-milling process, add water-wet behind A, the cotton linter opener, and in course of conveying, measure;
B, the cotton linter after wetting enter first double-screw pulp-milling, add entry once more in this machine right-handed screw the last period district, and cotton linter is washed, and discharge washings in the extruding of backpitch district and by filter plate, and control slurry mass dryness fraction, add water at two sections and wash; In aforementioned two sections, cotton linter is extruded, rubs and is cut off, and adds soup in the 3rd section, and mixes with cotton linter rapidly, continues to cut off, and controls out the slip mass dryness fraction;
After C, the slurry after mixing are sent by discharging opening, carry out the D step, it is temporary perhaps to enter first feed bin, carries out the D step then;
D, slurry are sent into second double-screw pulp-milling, add water at first section and second section and wash once more, and the 3rd section adds soup once more and react and mix;
Carry out the F step after E, reaction and even mixed slurry are sent by discharging opening, perhaps enter the temporary F step of carrying out then of second feed bin;
F, washing, desanding, the operation of manufacturing paper with pulp.
Above-mentioned pulping process technological requirement:
The moisture content that enters the first double-screw pulp-milling cotton linter is: 70-85%; Adding the water yield at first and second positive and negative helical region of first double-screw pulp-milling is 3-5m
3/ ton short flannel adds water pressurization 0.5-1.2Mpa;
Add soup at first double-screw pulp-milling the 3rd positive and negative helical region, institute adds soup and is:
NaOH (NaOH juice): 4-15% (to over dry cotton linter weight ratio)
H
2O
2(folding 100%): 2-10% (to over dry cotton linter weight ratio)
Sodium sulfite or ammonium sulfite: 0.1-10% (to over dry cotton linter weight ratio)
Waterglass (sodium metasilicate): 2-5% (to over dry cotton linter weight ratio)
EDTD (DTPA): 0.1-2.5% (to over dry cotton linter weight ratio)
Magnesium sulfate (MgSO
4): 0.1-5.0% (to over dry cotton linter weight ratio)
Soup adds pressure: 0.5-1.2Mpa;
The slurry that goes out first double-screw pulp-milling is dense: 20-45%, goes out first double-screw pulp-milling fibre length: the 2-4mm by temperature: 85-98 ℃; Advance first feed bin temperature: the 85-95 ℃, at first feed bin reaction time: the 1-3h;
It is dense to advance second double-screw pulp-milling slurry: 20-45%, first and second workshop section adds the water yield: 3-5m at second double-screw pulp-milling
3/ ton short flannel adds water pressurization 0.5-1.2Mpa; The 3rd workshop section adds soup at second double-screw pulp-milling, and institute adds soup and is:
NaOH (NaOH juice): 2-10% (to over dry cotton linter weight ratio)
H
2O
2(folding 100%): 1.0-6.0% (to over dry cotton linter weight ratio)
Sodium sulfite or ammonium sulfite: 0.1-10% (to over dry cotton linter weight ratio)
Waterglass (sodium metasilicate): 0.5-4.0% (to over dry cotton linter weight ratio)
EDTD (DTPA): 0.1-2.0% (to over dry cotton linter weight ratio)
Magnesium sulfate (MgSO
4): 0.1-5.0% (to over dry cotton linter weight ratio)
Soup adds pressure: 0.5-1.2Mpa;
It is dense to go out second double-screw pulp-milling slurry: 20-45%, go out second double-screw pulp-milling fibre length: the 2-4mm, and go out second double-screw pulp-milling temperature: the 85-95 ℃, advance second feed bin temperature: the 85-95 ℃, at second feed bin reaction time: the 1-3h.
Go out the second feed bin disposed slurry QUALITY STANDARD in the above-mentioned pulping process:
Whiteness: 75-90%, alpha-cellulose: 95.0-99.0%, yield: 70-90%, the degree of polymerization: DP=1000-1500, viscosity (cuprammonium): 15-35mp.s, ash content: 0.10-0.20%, iron: 20-100ppm.
Embodiment 3:
Aborning during the low polymerization degree product, promptly during DP:500-1000;
Slurry is temporary in feed bin or directly sends into batch cooking that it carries out boiling after double-screw pulp-milling is discharged, wash after boiling is finished, bleaching, desanding and the operation of manufacturing paper with pulp.Its technical process is:
In being transported to the double-screw pulp-milling process, add water-wet behind A, the cotton linter opener, and in course of conveying, measure;
B, the cotton linter after wetting enter first double-screw pulp-milling, add entry once more before this machine positive backpitch the last period, and cotton linter is washed, and add water at two sections and wash; In aforementioned two sections, cotton linter is extruded, rubs and is cut off, and adds soup in the 3rd section, and mixes with cotton linter rapidly;
After C, the slurry after mixing are sent by discharging opening, carry out the D step, it is temporary perhaps to enter feed bin, carries out the D step then;
D, slurry are sent into batch digester and are carried out boiling;
After E, boiling finish, wash, bleaching, desanding, the operation of manufacturing paper with pulp.
Above-mentioned pulping process technological requirement is as follows:
Enter double-screw pulp-milling cotton linter moisture content: 70-90%, adding the water yield at first and second section of double helix fiberizer is 3-8m
3/ ton short flannel adds water pressurization 0.5-1.2Mpa;
Add soup for the 3rd section at two roller fiberizers, soup adds pressure: 0.5-1.2Mpa, and institute adds soup and is:
NaOH (NaOH juice): 2-18% (to over dry cotton linter weight ratio)
Sodium sulfite or ammonium sulfite: 0.1-10% (to over dry cotton linter weight ratio)
H
2O
2(folding 100%): 2-15% (to over dry cotton linter weight ratio)
Waterglass (sodium metasilicate): 0.5-7.0% (to over dry cotton linter weight ratio)
EDTD (DTPA): 0.1-3.0% (to over dry cotton linter weight ratio)
Magnesium sulfate (MgSO
4): 0.5-6.0% (to over dry cotton linter weight ratio)
It is dense to go out two roller fiberizer slurries: 30-40%, and temperature: 85-95 ℃, go out first double-screw pulp-milling fibre length: the 3-4mm, feeding warehouse temperature: 85-95 ℃, at feed bin reaction time: 1-5h.
In the batch digester boiling:
Liquor ratio 1: 3.5-5.0, boiling temperature: 140-172 ℃.
Heating curve: from temperature of charge intensification 10-20 minute, be warming up to 120-125 ℃, under this temperature, be incubated 10min, little venting 5-15 minute; Intensification 10-30 minute, be warming up to 145-150 ℃, under this temperature, be incubated 30min, insulation finishes, little venting 5-15 minute; Continue to be warmed up to 165-170 ℃, insulation 30-60min, insulation finishes, blowing.
Through boiling disposed slurry quality index:
Whiteness: 60-90%, alpha-cellulose: 95.0-99.0%, viscosity: 10-35mp.s, the degree of polymerization: DP=1000-1500,, ash content: 0.20-0.50%, iron: 30-150ppm, R10 〉=99%, S18≤0.5%.
Embodiment 4:
The product performance index that adopts the above-mentioned embodiment of the present invention to be obtained is as follows:
Embodiment 5
Open one's minds according to of the present invention, this process is not limited to the production acetate fiber, and production other types viscose is also applicable.