CN104213209A - Wet-spinning coagulating bath - Google Patents

Abstract

The invention relates to wet-spinning coagulating bath for synthetic fibers and particularly relates to a wet-spinning coagulating bath for a PAN (polyacrylonitrile)-based carbon fiber protofilaments. The wet-spinning coagulating bath comprises a bath foam inlet buffer region, a channel region and a bath foam outlet collection region along the filament strand walking direction and is characterized in that the channel region is a sweeping surface inclined groove with two vertical side surfaces and a semicircular bottom; a middle-section reducing region is of a streamline reducing mode; a semicircular sweeping bottom surface of a rear-section constant-current region has a certain inclined slope along the filament strand walking direction. The wet-spinning coagulating bath has the beneficial effects of effectively reducing the concentration difference of an upper bath foam layer and a lower bath foam layer, realizing uniform and consistent forming of all parts of filament strands and reducing the performance dispersion of the filament strands.

Description

A kind of wet spinning coagulating tank

Technical field

The present invention relates to synthetic fiber wet spinning solidification forming equipment, particularly the wet spinning coagulating tank of a kind of polyacrylonitrile (PAN) base carbon fiber protofilament.

Background technology

PAN base carbon fibre is the main flow of current Industry of Carbon Fiber, output accounts for about 90% of worldwide carbon fiber total output, along with carbon fiber the improving constantly of strategic status in national economy and national defense construction, it is the common tackling key problem R&D direction of current all carbon fiber suppliers that low-cost and high-performance carbon fiber product is produced, in the process, spinning high-quality precursor is the prerequisite of producing high-performance carbon fibre at a high speed.

Current PAN precursor spinning technique mainly comprises wet method and wet-dry change two kinds, wherein adopt that the change of wet therapy forming process fibre number that dimethyl sulfoxide (DMSO) (DMSO) is solvent is little, solvent few, easy control precursor quality residual on fiber, be the spinning technique of current extensive use.In wet spinning, under spinning pack is immersed in the body lotion liquid level in dull and stereotyped wedged bottom horizontal coagulating tank, meet technological temperature, the PAN spinning solution of solid content measures through measuring pump, candle-shaped filter filters, after extruding from spinneret orifice, the top layer of stoste thread contacts with the coagulating bath of following current immediately, and be frozen into skim very soon, solvent DMSO concentration difference between formation stoste thread inside and coagulating bath and the concentration difference of coagulating agent water, the water in coagulating bath is made constantly to be diffused into thread inside by this skim, and the solvent in thread is also diffused into coagulating bath by cortex, along with the carrying out of double diffusion process and process of setting, solvent strength within stoste thread top layer progressively reduces, copolymer concentration raises gradually, when rising to critical concentration, PAN copolymer precipitating solidifies out, form the nascent strand of gel structure.In general, PAN spinning coagulation bath comprises three grades, and one-level coagulating bath is the most key, and coagulating tank can be divided into 3 sections, comprises spinning head section, coagulating tank stage casing and bath back segment.Strand is technology controlling and process link that is the most basic in polyacrylonitrile wet spinning process, most critical in the solidification forming condition of coagulating tank inside, and the stability and the bath COnCentratlon that comprise each section of body lotion flowing stablize two aspects.

Shanghai is closed and fine is passed through research (Zhao Peilin etc., the research II coagulating tank version of acrylic fibers high speed spinning and design principle, synthetic fiber, 1980, 01), spinning head section adopts the narrow shallow flat skewed slot of streamlined entry mode to bath stage casing, meet the peripheral liquid flowing speed of somewhere tow in bath to come into being equal or close to this place the bath design principle of tow gait of march, make bath stage casing body lotion flowing velocity and tow gait of march close, effectively reduce the frictional resistance that in high speed spinning process, tow is subject to, individual thread uniform force, lousiness, swing a phenomenon greatly to reduce, thus obtain the good tow of regularity.Streamlined entry mode makes spinning head section reduce to bath stage casing resistance simultaneously, significantly improves the body lotion vortex phenomenon around spinning head.But the stability problem of especially spinning head district bath COnCentratlon in bath is not considered in this research.

Yu Jun closes fine institute achievement in research according to Shanghai to have carried out improving (Yu Jun to dull and stereotyped Sloping Hearth coagulating tank, the design of rational coagulating tank version, Anqing Petrochemical Company, 2001,23 volumes, 01), distance spinning head 100mm place installs the internal diameter orifice plate slightly larger than spinning pack external diameter additional, rectification is carried out to body lotion flowing, Ring-cylindrical liquid stream is formed in annular gap between shower nozzle overcoat and orifice plate endoporus, surround nascent tow flow forward together, thus decrease the resistance to tow.Simultaneously at spinning pack rear, the baffle plate of one piece of some aperture of band being set, so as to disperseing the impulse force to spinning head district of coagulating bath, reducing the wild effect of flowing.But owing to not considering the stable of bath COnCentratlon, simple flow regime is improved does not make product appearance quality and physical index take an evident turn for the better.

The people such as State of Zhao Beam devise the coagulating tank of 2, a kind of front and back end body lotion entrance, bath stage casing fluid at Chinese patent CN200720103930.5, the following current of bath different phase or the multi-form mass-and heat-transfer mode of adverse current can be realized, coagulating bath distribution of concentration is even, but this form is not suitable with the actual production demand that PAN precursor wet spinning spinning pack Horizontal type spins position more.

The dull and stereotyped wedged bottom horizontal mode of interdigit dividing plate segmentation is spun in the many employings of PAN precursor wet spinning coagulating tank, existing design or improve all to improve body lotion fluidised form and overall density field stabilizes to basis, and exercisable concentration control mode generally imports and exports fixing point index of refraction by measuring body lotion realizes, this will certainly ignore, and coagulating tank is same solidifies the concentration difference of position especially between spinning head district body lotion levels.In the middle of actual production, spinning head district levels concentration difference sometimes can up to 1.9%, the uneven diffusion velocity directly having influence on solvent and coagulating agent of bath upper and lower layer concentration, lower floor's concentration is high, like this, analyzes with regard to one tow, upper strata is solidified soon, lower floor solidifies slowly, causes the inconsistent of levels strand freezing point, directly causes the carbonisation often encountered in producing to break the phenomenon of half rhizoid.

Summary of the invention

The object of the invention is the weak point for overcoming prior art, existing coagulating tank technology is improved, reduce the levels concentration difference of coagulating tank same position body lotion, especially the levels concentration difference in spinning head district, realize the even solidification between each synnema (especially more than 12K (12000 monofilament)) monofilament, produce the discrete less PAN precursor of performance between monofilament.

The coagulating tank functions of the present invention's design divides based on existing horizontal wet spinning technology, comprises body lotion ingress buffer, path district, body lotion outlet pooling zone three part, select 2 ~ 3mm stainless steel materials punch welding to form by tow direction of travel.Path district is made up of independently path mutual in overall water jacket and groove, and path quantity is determined according to spinning figure place.Path structure is the Semi round bottom skewed slot of bottom semicircular, two side elevation upper limb levels, spinning head district, reducing district, stage casing, back segment current stabilization district is divided into by length direction, spinning head district internal diameter or width are determined according to spinning specification, sectional area is larger, after the reducing of stage casing, back segment current stabilization district sectional area reduces the technological requirement to adapt to improve body lotion flow velocity.The screens of a band baffle plate is installed between the body lotion porch and spinning pack in spinning head district, be different from the rectification web plate of prior art, screens integrated baffles of the present invention and screens are in one, the back side is baffle plate, the bottom semicircular conical surface and two side elevations are the web plate of perforate, screens each several part adopts welding manner integrated, and screens adopts the modes such as welding or socket joint to be fixed on spinning head district, path allocation really.

Described body lotion ingress buffer width preferably 10 ~ 20cm, feed tube quantity, screen pack quantity with spin an one_to_one corresponding, described feed tube is vertically welded in bottom buffering area, the 20 order Steel nets of described screen pack preferred thickness 5 ~ 10cm, adopt bolt to fix or the mode such as socket joint is fixed on coagulating tank buffering area fluid plate correspondence and spins position place.

Described body lotion outlet pooling zone width preferably 30 ~ 50cm, comprise the first godet roller, liquid level adjustable plate and correspondence and spin the equipment such as the drain pipe of bit quantity, described first godet roller adopts large cornerite mirror face stainless steel roller, preferred diameter 15 ~ 20cm, described liquid level adjustable plate is combined by fixed head and adjustable plate, and the caliber of described drain pipe, nozzle position and feed tube are symmetrical.

Described coagulating tank path adopts the thick corrosion resistant plate punching press of thickness 2 ~ 3mm, is welded, and single path total length adjusts according to spinning speed, spinning solution index and long requirement of one-level coagulating bath leaching, and scope is between 1.9 ~ 2.5m; Two ends, path adopt welding manner to fix with buffering area fluid plate and pooling zone feed liquor plate respectively; Described path comprises spinning head district, reducing district, stage casing, path and back segment current stabilization district, path two side elevation upper limb level, the Semi round bottom horizontal setting of spinning head district, the back segment current stabilization district semicircle bottom surface lifting gradient preferably 3 ~ 5 °, reducing district, stage casing adopts streamline undergauge mode.

Described screens baffle plate is arranged on spinning head district, path perpendicular to spinning a center line, by tow direction of travel semicircle conical surface back baffle plate diameter or width suitable with spinning pack external diameter, anterior external profile diameter or width consistent with spinning head district, path Semi round bottom diameter or facade width, to reach the close-fitting object with path, two side elevations with spin a center line inclination angle and half-conical face cone angle consistent, preferably 8 ~ 10 °; Described screens installation site is positioned at spinnerets front, preferably 4 ~ 6cm, adopts the modes such as welding or socket joint to dock the anterior outer rim of screens along this position perpendicular to the two sides in path and track place, semicircle bottom surface; The described screens back side is imperforate baffle, the bottom semicircular conical surface and two side elevation perforates, preferably, aperture is the φ 3 ~ 5mm circular hole perpendicular to plate face, hole density and total body opening flux are determined according to body lotion circulation throughput requirements, the pore size distribution of the semicircle conical surface is large compared with two elevation holes density, and preferably two facades are 3: 2 with the ratio of semicircle conical surface flux.

Relative to aforementioned background art, coagulating tank provided by the invention includes has the screens of half-conical bottom surface web plate and the spinning shaft of Semi round bottom skewed slot, can effectively reduce the concentration difference of same spinning position, especially spinning head district body lotion levels.In the coagulating bath of PAN precursor, cause levels concentration difference to have two reasons, be first carry out with process of setting, in coagulating bath, DMSO concentration increases gradually, and the body lotion of large concentration is than great, naturally can to bottom sedimentation, secondly be the architectural feature decision of coagulating tank, should equal or close to the bath design principle of this place's spun filament gait of march for making coagulating tank design meet the peripheral liquid flowing speed in somewhere in bath, path back segment is often through reducing groove internal diameter and raising the object that trough floor height realizes reducing actual internal area, but the bottom Liang Ge corner basin shape distortion fierceness of flat skewed slot causes bottom land viscosity resistance to strengthen, body lotion shear rate improves, with the tow of Fast marching with compared with liquid stream, bottom land body lotion forms refluence to a certain degree, therefore with the carrying out of process of setting, bottom bath, show as levels concentration difference can be increasing, especially obvious in spinning head district.

By the technology of the present invention, adopt bottom surface, Semi round bottom path greatly can reduce body lotion basin deformation extent, bottom heavier body lotion in path can be made at utmost to reduce to remain in a standstill, advance with upper strata body lotion is almost synchronized; Adopt the half-conical bottom surface screens of band baffle plate, baffle plate can reduce body lotion and directly impact fragile nascent strand, half-conical bottom surface and two side elevation web plates not only can make body lotion flow field, spinning head front form stable laminar flow, and due to the reasonable layout of levels mesh, can make the most easily to cause bottom the spinning head district, path of larger concentration difference and also have fresh circulation body lotion, form direct flow impetus simultaneously, bottom is avoided to remain in a standstill, and then realize levels concentration one and to cause between tow monofilament coagulation grade even, produce the discrete less PAN precursor of filament properties.

Accompanying drawing explanation

Fig. 1 is coagulating tank general illustration;

Fig. 2 is coagulating tank side view;

Fig. 3 is single path side view;

Fig. 4 is single path left view

Fig. 5 is screens schematic diagram;

Fig. 6 is single path spinning center line levels body lotion flow field schematic diagram;

Fig. 7 is body lotion flow field, single path spinning center line left and right schematic diagram.

In figure, 1-buffering area, 2-screens, 201-baffle plate, 202-side elevation, 203-bottom semicircular cone bottom surface, 3-feed tube, 4-steel wire screen pack, 5-spinning pack, 6-comes into being tow, 7-drain pipe, 8-liquid level adjustable plate, 9-first godet roller, 10-pooling zone, 11-pooling zone feed liquor plate, 12-cell body, 13-path, 131-spinning head district, reducing district, stage casing, 132-path, 133-back segment current stabilization district, 14-screens, 15-buffering area fluid plate, 16-feed liquor house steward, 17-fluid house steward

Detailed description of the invention

The core of type of the present invention is to provide a kind of one-level coagulating tank for PAN precursor wet spinning, can effectively reduce body lotion levels concentration difference, realizes tow each several part uniformity and is shaped, and reduces performance between tow monofilament discrete.

In order to make the art personnel understand the present invention better, below in conjunction with accompanying drawing, the present invention is described in further detail:

As shown in Figure 1, a kind of wet spinning coagulating tank of the present invention, be mainly used in 4 and spin a 12K precursor wet spinning one-level coagulating bath, cell body 12 is square double-decker, and sidewall and bottom surface are formed by the thick corrosion resistant plate punch welding of 2 ~ 3mm, and central filler glass heat-insulating is cotton.Be divided into body lotion ingress buffer 1, path district and body lotion by buffering area fluid plate 15 and pooling zone feed liquor plate 11 (corrosion resistant plate) welded and installed in groove and export pooling zone 10.

Spin a uniform welding feed tube 3 according to correspondence bottom buffering area 1, quantity is 4, and feed tube 3 mouth of pipe bonding wire is concordant with cell body 12 buffering area bottom surface, and feed tube 3 is pooled to feed liquor house steward 16 (as shown in Figure 2) below coagulating tank.Buffering area fluid plate 15 correspondence is spun bit quantity and is spun a position opening, opening shape and size will be guaranteed to meet body lotion circulation and the requirement overcoming filtration resistance, the present embodiment opening is rectangle, opening part buffering area 1 side is with the steel wire screen pack 4 of bolted mode mounting strap framework, and quantity is 4.

Pooling zone 10 comprises the first godet roller 9, liquid level adjustable plate 8 and correspondence and spins the equipment such as the drain pipe 7 of bit quantity, described first godet roller 9 adopts large cornerite mirror face stainless steel roller with increasing friction force, described liquid level adjustable plate 8 is combined by fixed head and adjustable plate, the caliber of described drain pipe 7, nozzle position and feed tube 3 are symmetrical, drain pipe 7 is vertically welded in bottom pooling zone, is pooled to fluid house steward 17 below coagulating tank.

As shown in Figure 3, Figure 4, path district arranges 4 and separate solidifies path 13, adopt the thick corrosion resistant plate punching press of thickness 2 ~ 3mm, be welded, spinning head district 131, reducing district, stage casing, path 132 and 133 3, back segment current stabilization district part can be divided in described path 13, and each part forms by semicircle bottom surface connecing dull and stereotyped facade.Spinning head district 131 Semi round bottom horizontal setting, reducing district, stage casing 132 adopts streamlined undergauge mode, spinning direction, semicircle bottom surface, back segment current stabilization district 133 gradient 3 ~ 5 °.Spinning head district, single path 13 131 is 2: 3 with reducing district 132 length ratio, and back segment current stabilization district 133 length and front two sections of sums are quite or slightly long.Path 13 width is maximum in spinning head district 131, through reducing district 132 streamline reducing reduced width, the lifting of semicircle floor height, and connects with back segment current stabilization district 133 streamline.Two ends, path 13 adopt welding manner to fix with buffering area fluid plate 15 and pooling zone feed liquor plate 11 respectively, and the vertical butt welding in spinning head district 131, current stabilization district 133 end tack welding, avoids machined burrs to damage tow.

As shown in Figure 5, screens 2 welds integrated by baffle plate 201, the bottom semicircular conical surface 203 with two side elevations 202.Backing shield 201 is imperforate baffle, and profile is made up of a semicircle and a rectangle; The bottom semicircular conical surface 203 and two side elevation 202 perforates, aperture is the 3 ~ 5mm diameter circular aperture perpendicular to plate face, total body opening flux is determined according to body lotion internal circulating load throughput requirements, and preferably two facades are 3: 2 with the ratio of semicircle conical surface flux, and the pore size distribution of the semicircle conical surface is large compared with two elevation holes density.By the tow direction of travel semicircle conical surface 203 back diameter or width suitable with spinning pack 5 external diameter, anterior external profile diameter or width consistent with spinning head district 131, path Semi round bottom diameter, to reach object close-fitting with path 13, two side elevations with spin a center line inclination angle and half-conical face cone angle consistent, preferably 8 ~ 10 °, screens 14 installation site is positioned at 4 ~ 6cm place, spinnerets 5 front, spinning head district 131, path, along this position perpendicular to the two sides in path 13 and the anterior maximum outer rim of track place, semicircle bottom surface positioning welding screens 14, weldering meat is evenly very thin, path 13 or screens 14 is avoided to be out of shape, screens 14 back baffle plate 201 should not hinder gooseneck to operate.

As shown in Figure 6, Figure 7, according to the producing cause of coagulating bath same position levels uneven concentration in aforesaid background technology, present embodiment can be overcome targetedly:

1, fresh body lotion is through buffering, after filtration, through the further current stabilization of screens 2 baffle plate 201, from spinning pack 5 up and down all directions parcel nascent tow 6 flow with layer flow mode, especially the half-conical veil plate 203 of screens 2, fresh body lotion is had directly to mix below the spinning head that spinning head district 131 can be made the most easily to form concentration buildup, and form initial flow power, direct promotion path 13 bottom liquid stream moves ahead, because screens 2 half-conical veil plate 203 unit are flux is larger, although path 13 bottom body lotion proportion is larger, the hole density of reasonable disposition two side elevation 202 and half-conical bottom surface 201, bottom body lotion can be impelled and upper strata body lotion is synchronized moves ahead, avoid the formation of concentration difference, realize same synnema uniformity solidification forming.

2, spinning shaft of the present invention is all Semi round bottom skewed slot along journey, while body lotion light grade upper reaches gives tow lifting force, due to semicircular bottom basin shape, significantly reduce the bottom land viscous force of underlying liquid stream, improve body lotion bottom flow field, in the process of body lotion circulation, bottom land detention layer thickness and the body lotion viscous flow amount of optional position, path 13 reduce greatly, fundamentally solve the difference problem of wet spinning one-level coagulating tank levels concentration, especially realize the omnidistance uniformity of one-level coagulating bath to the large tow wet spinning of more than 12K to solidify, to produce the discrete less PAN precursor of performance between monofilament.

Claims (7)

1. a coagulating tank device, for PAN base carbon fiber protofilament wet spinning, comprise body lotion ingress buffer (1), path district and body lotion outlet three, pooling zone part, it is characterized in that: each path, path district (13) is two side elevations, bottom semicircular sweeping face skewed slot, screens (2) is installed in spinning head district, path (131).

2. coagulating tank according to claim 1, it is characterized in that: overall path two side elevation upper limb level, the bottom surface horizontal setting of spinning head district, path (131) semicircle sweeping, reducing district, stage casing (132) adopts streamlined undergauge mode, and back segment current stabilization district (133) semicircle sweeping bottom surface is certain gradient along tow direct of travel.

3. coagulating tank according to claim 1, single path (13) reducing district (132) length is larger than spinning head district (131) length, and back segment current stabilization district (133) length is equal with front two sections of sums or determine according to soaking long requirement.

4. coagulating tank according to claim 1, single path (13) width is maximum in spinning head district (131), through reducing district (132) streamline reducing reduced width, the progressively lifting simultaneously of semicircle floor height, and connect with back segment current stabilization district (133) streamline.

5. coagulating tank according to claim 1, screens (2) integrated baffles (201) and web plate are in one, web plate is made up of the bottom semicircular conical surface (203) and two side elevations (202), the bottom semicircular conical surface (203) cone angle and two side elevations (202) consistent with the inclination angle of spinning center line.

6. coagulating tank according to claim 1, screens (2) rear vertical is arranged on front, spinnerets position, path, and back distance is suitable to facilitate gooseneck to be operating as.

7. coagulating tank according to claim 1, screens (2) two side elevation (202) is different from the perforate density of the bottom semicircular conical surface (203), and bottom density ratio facade is large.