Summary of the invention
The technical problem that the present invention solves is, a kind of preparation method with superhigh molecular weight polyethylene fibers of better tensile property is provided.
For solving above technical problem, the invention provides a kind of method for preparing ultra-high molecular weight polyethylene fibers, may further comprise the steps:
A) ultra-high molecular weight polyethylene powder and solvent being obtained behind the suspension obtaining concentration through double screw extruder extruding dissolving through swelling again is 4%~25% spinning solution, and described solvent is to be the hydrocarbon of liquid under the room temperature;
B) described spinning solution is obtained gel fiber through spray silk, cooling;
C) described gel fiber is applied 1 times~10 times predraft, the gel fiber after the predraft is left standstill after 12 hours~48 hours through extraction, drying;
D) dried gel fiber is applied 4 times~60 times hot drawing-off in 70 ℃~160 ℃ temperature range and obtain superhigh molecular weight polyethylene fibers.
Preferably, the predraft in the step c) is to carry out in 4 ℃~25 ℃ path.
Preferably, in described path, feed the temperature saturated steam identical with the path temperature.
Preferably, the step b) specific implementation is for described spinning solution through draw ratio being 6/1~30/1 the spinneret orifice speed spray silk with 0.5m/min~10m/min, obtain solidifying strand through 0 ℃~36 ℃ cooling then, again the coagulated yarn bar is applied the jet stretch that is no more than 2 times and obtain gel fiber.
Preferably, described solvent is selected from one or more in tetrahydronaphthalene, decahydronaphthalenes, kerosene, paraffin oil or the paraffin.
Preferably, the inlet temperature of the suspension feeding double screw extruder described in the step a) is 85 ℃~120 ℃, 120 ℃~230 ℃ of the temperature of middle extruding dissolving, outlet temperature is 200 ℃~260 ℃, the rotary speed of double screw extruder is 30r/min~300r/min, and the time of staying of suspension in double screw extruder is for being no more than 10 minutes.
Preferably, the hot drawing-off of step d) may further comprise the steps:
D1) dried gel fiber is fed first drawing machine successively, temperature is 70 ℃~110 ℃ the first hot path, and second drawing machine, described second drawing machine are that fiber applies and leads a times Q
1It is 2 times~15 times drawing-off;
D2) will be 105 ℃~160 ℃ the second hot path through the precursor after second drawing machine drawing-off feeding temperature, the 3rd drawing machine applies times Q that leads less than second drawing machine by the 3rd drawing machine to fiber
1Drawing-off after make superhigh molecular weight polyethylene fibers, the length in the described second hot path is greater than the length in the first hot path.
Preferably, the rice number L of the length in the described first hot path
1Multiple Q with second drawing machine
1Satisfy relation of plane: 1.2Q down
1≤ L
1≤ 2.0Q
1
The rice number L of the length in the preferred described second hot path
2Rice number L with the length in the first hot path
1Satisfy relation of plane: 1.2L down
1≤ L
2≤ 3L
1
Preferably, the roll temperature of described first drawing machine and second drawing machine is 70 ℃~160 ℃.
Preferably, the roll temperature of described the 3rd drawing machine is 4 ℃~25 ℃.
The invention provides a kind of method for preparing ultra-high molecular weight polyethylene fibers.The present invention adopts the gel spinning legal system to be equipped with ultra-high molecular weight polyethylene gel fiber, then gel fiber is applied 1 times~10 times predraft, owing to the lubrication of solvent is arranged, can make gel fiber that distortion uniformly takes place, for extraction-dried hot-stretch lays the foundation.The present invention is carrying out after the predraft it being left standstill a period of time to fiber, because phase separation, a part of solvent can be separated out, and the macromolecular chain in the gel fiber interacts and strengthens, and therefore also is beneficial to the lifting of follow-up fibrous mechanical property.The present invention can effectively reduce the internal stress that produces in the fiber by improving the technology of hot-stretch, helps the drawing effect of fortifying fibre, improves the mechanical property of fiber.
The specific embodiment
The invention provides a kind of method for preparing ultra-high molecular weight polyethylene fibers, may further comprise the steps:
A) ultra-high molecular weight polyethylene powder and solvent being obtained behind the suspension obtaining concentration through double screw extruder extruding dissolving through swelling again is 4%~25% spinning solution, and described solvent is to be the hydrocarbon of liquid under the room temperature;
B) described spinning solution is obtained gel fiber through spray silk, cooling;
C) described gel fiber is applied 1 times~10 times predraft, the gel fiber after the predraft is left standstill after 12 hours~48 hours through extraction, drying;
D) dried gel fiber is applied 4 times~130 times hot drawing-off in 70 ℃~160 ℃ temperature range and obtain superhigh molecular weight polyethylene fibers.
In order to reach purpose of the present invention, described ultra-high molecular weight polyethylene powder is weight average molecular weight (M
w) be (1~7) * 10
6Linear ultra-high molecular weight polyethylene, preferred, described ultra-high molecular weight polyethylene is that weight average molecular weight is (1.5~4.5) * 10
6Linear ultra-high molecular weight polyethylene, preferred, the weight average molecular weight of described ultra-high molecular weight polyethylene is (1.8~4.0) * 10
6Linear ultra-high molecular weight polyethylene.The powder size of described ultra-high molecular weight polyethylene is 40 μ m (micron)~200 μ m, and preferred, described ultra-high molecular weight polyethylene powder size is 80 μ m~180 μ m.
According to method of the present invention, described solvent as the ultra-high molecular weight polyethylene spinning solution is to be the hydrocarbon of liquid under the room temperature, preferably, can be hydrogenated naphthalene or alkane series, for example can be selected from one or more the solvents in tetrahydronaphthalene, decahydronaphthalenes, kerosene, paraffin oil or the paraffin as ultra-high molecular weight polyethylene, preferred, can select molecular weight for use is 40~1000 the paraffin oil solvent as ultra-high molecular weight polyethylene.
According to the present invention, with described ultra-high molecular weight polyethylene and solvent swelling 20 minutes~200 minutes in temperature is 70 ℃~150 ℃ scope, preferably, with described ultra-high molecular weight polyethylene and solvent swelling 25 minutes~55 minutes in temperature is 75 ℃~125 ℃ scope.In order to prepare the high super high molecular polyethylene solution of spinning property, the percentage by weight of ultra-high molecular weight polyethylene is 4%~25% in the spinning solution provided by the invention, preferably, the percentage by weight of ultra-high molecular weight polyethylene is 5%~19% in the spinning solution, preferred, the percentage by weight of ultra-high molecular weight polyethylene is 7%~15% in the spinning solution.
According to the present invention, the feeding mouth temperature of double screw extruder is 85 ℃~120 ℃, 120 ℃~230 ℃ of the temperature of middle extruding dissolving, and outlet temperature is 200 ℃~260 ℃; The time of staying of suspension in double screw extruder, preferred, the time of staying of suspension in double screw extruder is 3~8 minutes, and be preferred in order to be no more than 10 minutes, and the time of staying of suspension in double screw extruder is 4~6 minutes; The rotary speed of double screw extruder be 30~300r/min (rev/min), preferred, the rotary speed of double screw extruder is 70~270r/min, and is preferred, the rotary speed of double screw extruder is 90r/min~200r/min.
According to the present invention, adopt gel spinning prepared superhigh molecular weight polyethylene fibers.The process conditions of gel spinning are: the aperture of spinneret orifice is 0.6mm~5mm, and preferred, the aperture of spinneret orifice is 0.7mm~5mm; Spinneret orifice draw ratio L/D is 6/1~30/1, and preferred, spinneret orifice draw ratio L/D is 10/1~20/1; The spinning solution rate of extrusion is 0.5m/min~10m/min, and preferred, the spinning solution rate of extrusion is 1m/min~5m/min; After extruding, spinning solution is through 20 ℃~60 ℃ cooling and shaping, and the shower nozzle drafting multiple is no more than 2 times; Preferably, the shower nozzle drafting multiple is no more than 1.8 times.
According to the present invention, after the gel fiber moulding, it is applied 1 times~10 times predraft, because strand structure this moment finalizes the design almost, lay the foundation for a follow-up super times hot-stretch thereby it is applied the stretching, extension that after the predraft macromolecular chain is carried out to a certain degree, but leading of predraft doubly can not be excessive; Preferably, the gel fiber after the moulding is applied 1.5 times~7 times predraft, preferred, the gel fiber after the moulding applied 1.9 times~6 times predraft.In order further to guarantee that the structure in the gel fiber does not change under heat effect, preferred, predraft in being 4 ℃~25 ℃ path, temperature is carried out, and preferred, predraft is carried out in 5 ℃~15 ℃ path.Because nascent gel fiber structure is comparatively fragile, therefore in order to make solvent and gel fiber be in stable status more, when predraft, in the path, feed in the saturated steam that the path environment temperature equates and guarantee that further gel fiber structure on perpendicular to the draw direction of strand does not change, thereby make it possess more excellent tensile properties.
According to the present invention, after gel fiber is carried out predraft, it need be left standstill 12 hours~48 hours.This be because, gel fiber is in the process that leaves standstill, because the effect that is separated, part solvent can be separated out from fiber, thereby the interaction between the ultra-high molecular weight polyethylene macromolecular chain in the frozen glue network skeleton is enhanced, the increase of the Van der Waals force between this macromolecular chain is further extruded the solvent in the network again, and meanwhile gel fiber shrinks on its vertical and horizontal.This contraction increases the commissure point of ultra-high molecular weight polyethylene macromolecular chain, and the point that tangles does not increase, and can improve the tensile property of fiber, makes it bear bigger pulling force when surpassing times hot-stretch follow-up.Preferably, the gel fiber after the predraft is left standstill obtained super high molecular polyethylene fiber precursor in 16 hours~26 hours.
According to the present invention, the extractant of selecting for use should have good mixing mutually or compatibility to solvent, and has low boiling point and high volatility.Used extractant can be volatile lower paraffin hydrocarbon or halogenated hydrocarbons, for example when using paraffin oil as solvent, can select for use hexane, heptane, toluene, chloromethanes, solvent wet goods as extractant, and is preferred, selects for use industrial naptha as extractant.Polyethylene fiber precursor carries out drying to it and makes the extractant volatilization through after extracting in 40 ℃~90 ℃ temperature range.
According to the present invention, when precursor was carried out drying, baking temperature can be 40 ℃~90 ℃, and preferred, baking temperature is 50 ℃~70 ℃.The temperature that surpasses times hot-stretch is 70 ℃~160 ℃, and is preferred, surpasses a times hot-stretch in 85 ℃~135 ℃ temperature range.Herein, when fiber being applied stretching, need under the condition of heating, carry out, therefore the pipe that makes the both ends open that precursor passes, casing, cylinder etc. are arranged between drawing machine, feed the gas that needs temperature then therein, the cylinder that hot herein path, path promptly instigate fiber to pass, but be not limited thereto.
According to the present invention,, need apply the stretching of two-stage at least to gel fiber after the drying in order to improve the mechanical property of fiber.
The invention provides following drawing process:
D1) dried gel fiber is fed first drawing machine successively, temperature is 70 ℃~110 ℃ the first hot path, and second drawing machine, described second drawing machine are that fiber applies and leads a times Q
1It is 2 times~15 times drawing-off;
D2) feeding of the precursor after will protracting through second drawing machine temperature is 105 ℃~160 ℃ the second hot path, the 3rd drawing machine, times Q that leads less than second drawing machine that fiber is applied by the 3rd drawing machine
1Drawing-off after make superhigh molecular weight polyethylene fibers, the length in the described second hot path is greater than the length in the first hot path.
According to the present invention, after gel fiber is finished first order drawing-off by second drawing machine, macromolecular chain in the precursor is drawn close mutually, active force increases each other, highly crystalline and orientation take place, because bigger distortion has taken place in the internal stress of the inner meeting generation of gel fiber with the drafting force acting in opposition, this internal stress can reduce the drawing effect of next stage, and also can make the final mechanical properties decrease of fiber.In order to reduce the effect of internal stress, when precursor being carried out drawing-off, need to eliminate the internal stress in the precursor by the 3rd drawing machine to precursor.Therefore the length in the second hot path of the present invention is greater than the length in the first hot path, and the 3rd drawing machine lead doubly leading doubly less than second drawing machine, internal stress in the precursor can obtain discharging in long distance, lead when stretching under the doubly little situation relatively effectively like this.
According to the present invention, when precursor is carried out drawing-off, need to select suitable hot path length, the length in hot path and the deflection of precursor have confidential relation, and the deflection of precursor mainly doubly decides by leading, herein, the long measure in hot path is a rice, leads a times dimensionless.
According to the present invention, the rice number L of the length in the first hot path
1Lead times Q and need satisfy 0.5Q≤L what precursor applied with second drawing machine
1The relation of≤2.0Q, preferred, the rice number L of the length in the first hot path
1Lead times Q and need satisfy 0.8Q≤L what precursor applied with second drawing machine
1The relation of≤1.5Q.For example, when second drawing machine is precursor when applying 2 times of drawing-offs, the rice number L of the length in the first hot path so
1Should satisfy (0.5 * 2=1)≤L
1≤ (2.0 * 2=4), preferred, (0.8 * 2=1.6)≤L
1≤ (1.5 * 2=3); Promptly the length in the first hot path is 1 meter~2.4 meters, and preferred, length is 1.6 meters~3 meters.Hot path length is too short, and the precursor time of staying is short, and therefore stretch and may damage fiber, hot path overlong time, drawing-off efficient step-down, effect is bad.The length L in the second hot path
2Satisfy following relation: 1.2L with the length in the first hot path
1≤ L
2≤ 3L
1
According to the present invention, the carry-over pinch rolls temperature of first drawing machine can be 70 ℃~160 ℃, the carry-over pinch rolls temperature of second drawing machine can be 70 ℃~160 ℃, this is because will give warm of precursor earlier, and gets in drawing-off and to make precursor keep high temperature to help the further stretching of precursor in the process always.In the 3rd drawing machine, the invention provides the cold roller of 4 ℃~15 ℃ of temperature, this is because finish the stretching of precursor is made after the superhigh molecular weight polyethylene fibers, make fiber fast cooling make the macromolecular orientation structure under the high temperature be saved to room temperature, help improving fibrous mechanical property.In addition,, therefore, also fiber at room temperature can be left standstill more than 24 hours, be used to eliminate stress, reach more excellent performance because fiber has been carried out quick cooling.The present invention can be the drawing machine well known to those skilled in the art that contains a plurality of carry-over pinch rolls commonly used in the fields such as spinning, high-performance fiber for drawing machine and without particular limitation, and for the number of the roller of drawing machine, the present invention is also without particular limitation.
According to the present invention, when surpassing times hot-stretch, by making leading doubly of applying later less than the leading doubly of front, and the hot path that prolongs the back can effectively reduce the stress that the drawing-off of front produces, thereby makes fiber have more excellent mechanical property.Cylinder or pipe with an import and an outlet that described path promptly instigates precursor to pass feed the gas for precursor heating or cooling in the cylinder.
Fibrous mechanical property is tested as follows among the present invention: adopt the DXLL-20000 electronic tensile machine to measure the intensity and the modulus of fiber, test condition is for pressing from both sides apart from 250mm decrease speed 50mm/min.
According to the present invention, in order to estimate stretching to the inhomogeneity influence of fibrous mechanical property, the present invention adopts and handles test result in the following method:
The performance number of each sample: get X
1, X
2... X
nBe total to the performance number of n sample;
Sample performance is got arithmetic mean of instantaneous value promptly:
---------------------------------------------------------formula 1
In the formula 1: X
i---the performance number of each sample,
N---sample number;
Standard deviation (S) adopts following method:
--------------------------------------------------formula 2
In the formula 2, S is a standard deviation, and other symbol is with formula 1;
Coefficient of dispersion (CV) adopts following method:
--------------------------------------------------formula 3
In the formula 3, CV is a coefficient of dispersion, and other symbol is with formula 2.
In order further to understand the present invention, below in conjunction with embodiment the preferred embodiment of the invention is described, but should be appreciated that these describe just to further specifying the features and advantages of the present invention, rather than to the restriction of claim scope of the present invention.
Embodiment
In order to reach better comparative effectiveness, in following embodiment and comparative example, all use identical raw material and drawing machine to prepare superhigh molecular weight polyethylene fibers, the path that drawing-off is used is adjusted its length as required.The weight average molecular weight M of used ultra-high molecular weight polyethylene
WBe 2.4 * 10
6, powder size is 80 μ m~120 μ m, and solvent for use is low viscosity paraffin oil (η=7.5), and used extractant is No. 120 solvent naphthas.
Embodiment 1
80kg ultra-high molecular weight polyethylene powder and 920kg paraffin oil be put in the swelling still 101 under temperature is 105 ℃ condition, stir swelling and obtained suspension in 40 minutes.
The suspension that obtains sent into send into double screw extruder 103 again after being cooled to 25 ℃ in the material storage kettle 102 and push dissolving.Wherein, mouthful temperature of sending into of double screw extruder is that 100 ℃, medium temperature are that 185 ℃, outlet temperature are 225 ℃, and the time that suspension stops in double screw extruder is 5 minutes, the double screw extruder rotary speed be 180rpm (rev/min).Suspension is through the extruding dissolving of double screw extruder, and the branch subsolution twines greatly, makes transparent gel spinning solution.
With gel spinning solution through measuring pump 104, have spinnerets (the orifice diameter 0.8mm in 400 holes, draw ratio L/D is 10/1) extrude with the spray silk speed of 1m/min that to enter temperature be that 25 ℃ the tank 106 that solidifies makes strand typing, the jet stretch of adopting 107 pairs of gel fibers of jet stretch machine to apply 1.5 times then obtains gel fiber.Is that 15 ℃ path 108 adopts the predraft machines to apply 1.6 times predraft with gel fiber by temperature, feeds temperature and be 15 ℃ saturated steam when carrying out predraft in the path.Gel fiber after the predraft put into leave standstill bucket and 110 left standstill 18 hours.
Referring to Fig. 2, adopt No. 120 solvent naphthas to carry out five grades extraction the gel fiber after leaving standstill, described five grades extraction is to make gel fiber successively from low to high through first extraction box 201, second extraction box 202, the 3rd extraction box 203, the 4th extraction box 204, the 5th extraction box 205, wherein the solvent naphtha in the 5th extraction box flow through successively from high to low the 4th extraction box, the 3rd extraction box, second extraction box, first extraction box, solvent naphtha and gel fiber to give direction opposite, arrow is represented the flow direction of solvent naphtha.Gel fiber after the extraction successively first drying box 206 55 ℃ of dryings, again through second drying box 207 65 ℃ of dryings.
Referring to Fig. 3, dried gel fiber feeds first drawing machine, 301, the first hot path 302, second drawing machine, 303, the second hot path 304, the 3rd drawing machine 305 successively and carries out the two levels of thermal drawing-off, adopts then to receive silk device 308 and receive silk.Wherein, the temperature in the first hot path is 100 ℃, and the temperature in the second hot path is 125 ℃.First drawing machine, second drawing machine, the 3rd drawing machine all are five roller drawing machines, in order to reach the object of the invention, for drawing machine the present invention and unrestricted, lead doubly as long as can satisfy.The roller temperature of first drawing machine is 100 ℃, and the roller temperature of second drawing machine is 125 ℃, and the roller temperature of the 3rd drawing machine is 15 ℃.Second drawing machine doubly is 5.5 times to leading of applying of precursor, and the 3rd drawing machine leads doubly 4.8 times to what precursor applied.
After gel fiber surpasses times hot-stretch through two-stage, adopt receipts silk device 308 to receive silk and obtain superhigh molecular weight polyethylene fibers.
Mechanics Performance Testing is carried out in sampling to fiber, gets ten samples at every turn, and results averaged is with the table 2 that the results are shown in after drawing and calculating
Embodiment 2~embodiment 5, comparative example 1~comparative example 2 have all prepared the suspension of same concentrations according to the swell process identical with embodiment 1, then to prepare gel spinning solution with embodiment 1 identical extruding dissolution process, extraction, dry, stretcher is identical with embodiment 1, technological parameter is referring to table 1.Behind the preparation superhigh molecular weight polyethylene fibers, fiber is carried out Mechanics Performance Testing, get ten samples at every turn, results averaged is calculated the CV value, and test and result of calculation see Table 2.
Embodiment 6
In the present embodiment, 100kg ultra-high molecular weight polyethylene powder and 900kg paraffin oil are put in the swelling still 101 and under temperature is 108 ℃ condition, stir swelling and obtained suspension in 45 minutes.
The suspension that obtains sent into be cooled to 25 ℃ in the material storage kettle 102 and send into double screw extruder 103 again and push dissolving.Wherein, mouthful temperature of sending into of double screw extruder is that 105 ℃, medium temperature are that 190 ℃, outlet temperature are 220 ℃, and suspension time of staying in double screw extruder is 5 minutes, and the double screw extruder rotary speed is 200rpm.Suspension is through the extruding dissolving of double screw extruder, and the branch subsolution twines greatly, makes transparent gel spinning solution.
According to preparing gel fiber with embodiment 1 identical spinning technique.
Is that 15 ℃ path 108 adopts the predraft machines to apply 2 times predraft with the gel fiber that makes by temperature, feeds temperature and be 15 ℃ saturated steam when carrying out predraft in the path.Gel fiber after the predraft put into leave standstill bucket and 110 left standstill 18 hours.
Referring to Fig. 4, dried gel fiber is fed first drawing machine, 401, the first hot path 402, second drawing machine, 403, the second hot path 404, the 3rd drawing machine the 405, the 3rd hot path 406, the 4th drawing machine 407 successively carry out three grades of hot drawing-offs, adopt then and receive silk device 408 and receive silk.Wherein, the temperature in the first hot path is 90 ℃, and the temperature in the second hot path is 110 ℃, and the temperature in the 3rd hot path is 130 ℃.First drawing machine, second drawing machine, the 3rd drawing machine, the 4th drawing machine all are five roller drawing machines.The roller temperature of first drawing machine is identical with the temperature in the first hot path, is 90 ℃; The roller temperature of second drawing machine is identical with the temperature in the second hot path, is 110 ℃; The temperature in the roller Wen Yudi three hot paths of the 3rd drawing machine is identical, is 130 ℃; The roller temperature of the 4th drawing machine is 15 ℃.Second drawing machine doubly is 3.2 times to leading of applying of precursor, and the 3rd drawing machine doubly is 2.6 times to leading of applying of precursor, and the 4th drawing machine doubly is 2.1 times to leading of applying of precursor.
After gel fiber surpasses times hot-stretchs through three grades, adopt receipts silk device 408 to receive silk and obtain superhigh molecular weight polyethylene fibers.
Mechanics Performance Testing is carried out in sampling to fiber, gets ten samples at every turn, and results averaged is with the table 2 that the results are shown in after drawing and calculating
After embodiment 7~embodiment 10, comparative example 3~comparative example 4 have all prepared the spinning solution of same concentrations according to swelling identical with embodiment 6 and extruding dissolution process, spinning solution adopted carry out three grades of hot-stretchs again after the equipment spinning identical with embodiment 6, predraft, extraction, the drying and prepare superhigh molecular weight polyethylene fibers, other technological parameter is referring to table 2.Behind the preparation superhigh molecular weight polyethylene fibers, fiber is carried out Mechanics Performance Testing, get ten samples at every turn, results averaged is calculated the CV value, and test and result of calculation see Table 2.
Table 1 superhigh molecular weight polyethylene fibers preparation technology parameter table
Continuous table 1 superhigh molecular weight polyethylene fibers preparation technology parameter table
The table 2 superhigh molecular weight polyethylene fibers embodiment and the comparative example performance table of comparisons
From above narration as can be seen, when the preparation superhigh molecular weight polyethylene fibers,, can obviously improve the tensile property of fiber if gel fiber is applied certain predraft.By reasonable coupling drafting multiple and path length, can improve the mechanical property of fiber.And along with the increase of stretching progression, fibre property also can increase thereupon.
The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.