FIELD OF THE INVENTION
[0001] The invention relates to a method of preparing fiber of High Molecular Weight Polyethylene
(HMWPE), specifically, a method of preparing fiber of Ultra High Molecular Weight
Polyethylene (UHMWPE).
BACKGROUND OF THE INVENTION
[0002] A method of preparing a high strength, high modulus polyethylene (PE) fiber from
UHMWPE gel
via drawing or stretching technology is disclosed in UK Patent Nos.
GB2042414 and
GB2051667, assigned to DSM Company, Netherlands in 1979. After that, this technology was industrialized
by Allied Company from the U.S., Toyobo-DSM Company, a joint venture by Japan and
Netherlands, as well as Mitsui Company from Japan. In 1982, Allied Company obtained
US Patent No. 4413110, which covers a process of preparing UHMWPE fiber. Donghua University in China also
obtained Chinese Patent Nos.
89107905 and
97106768 in this area.
[0003] The main procedures for preparing UHMWPE gel fiber are as follows: UHMWPE is added
into a suitable solvent to prepare a solution by stirring; the solution is extruded
by an extruder and spun through a spinnerette, followed by cooling, extraction, drying,
and stretching, to form the desired fiber product. To obtain a high strength and high
modulus fiber, key steps include the preparation of a homogeneous UHMWPE solution,
and the extraction with a second solvent to remove the large amount of a first solvent
contained in gel fiber prior to stretching of the gel fiber.
[0004] As the molecular weight of polyethylene increases, its macromolecular size is also
increasing, and the entanglement exists among such macromolecules. The entanglement
among the macromolecules is beneficial to increase the draw ratio and can result in
highly oriented fiber with higher strength and modulus. However, the viscoelastic
effect due to the entanglement among the macromolecules of polymer makes the dissolving
process much more complicated, and is not beneficial to the dissolving and shaping
process. Therefore, the entanglement among the macromolecules should be controlled.
The state of such entanglement can be controlled by heat treatment, solvent treatment
and cutting.
[0005] The molecular weight for polymer and low molecule solvent is quite different. Polymer
has a long molecule chain and it is difficult for the polymer to move. Due to the
strong intra-molecular interactions and entanglement among the polymer molecules,
the polymer does not diffuse into a solvent when the polymer and low molecule solvent
are just mixed. If the conventional dissolution method is used to prepare the solution,
the polymer powder tends to be aggregated, or form a gel solid due to incomplete permeation
of the solvent, and a homogeneous solution cannot be obtained. Furthermore, the Weissenberg
Effect (climbing effect) will appear due to the viscoelastic effect caused by entanglement
between macromolecules of polyethylene when stirring.
[0006] With the increase of molecule weight, polymer concentration and stirring speed, the
Weissenberg Effect will be more effective. Accordingly, it will become more difficult
to obtain a homogeneous solution.
[0007] Certain patents propose various methods for solving the problem. For example,
EP 0255618 discloses that a hydrocarbon mixture free of naphthalin and diphenyl, with boiling
point around 180-250°C is obtained after a rectification separation from hydrogenated
coal oil. Such hydrocarbon mixture is further mixed with UHMWPE and decahydronaphthalene
at 135°C, agitated for several hours to form a PE solution. The concentration of the
PE solution is no greater than 50%.
[0008] Japanese Patent No.
59232123 describes a process to mix UHMWPE with small amount of a solvent for several minutes,
followed by heating, then more solvent is added gradually with stirring to form a
solution containing UHMWPE.
[0009] In an example disclosed in Japanese Patent No.
63-15838, a fractional coal oil is catalytically hydrogenated to provide a solvent. The solvent
is further added with an anti-oxidant and PE, and the resulting mixture is agitated
for 3 hours at 140°C to form a 10%(w/w) UHMWPE solution.
[0010] In some cases, the problem is solved using a two-step process including swelling
and dissolving. Chinese Patent No.
970106768 discloses that an alkane hydrocarbon solvent can be used to swell PE under certain
conditions, and to prepare a suspension solution containing UHMWPE.
[0011] Chinese Patent No.
97101010 describes that a pre-swelling pan equipped with an new mixer baffle is used to swell
UHMWPE to form a suspension solution so as to avoid the Weissenberg Effect of UHMWPE
during dissolving and stirring.
[0012] Chinese Patent No.
20041009607615, titled "A Method For Continuous Mixing and Preparation of UHMWPE Solution," discloses
the use of a static mixer with a screw having a small Length/Diameter ratio to allow
continuous preparation of UHMWPE solution. In Chinese Patent No.
85107352A, DSM company provides a method of preparing a homogeneous solution of polymer, comprising:
feeding a fine polymer powder and a solvent into an extruder, where a suspension and
a solution is formed within the extruder, with an operation temperature above the
melting point of the polymer and at a mechanical cutting rate of about 30-2000S
-1. However, this method can damage the molecule chain of UHMWPE and result in a decrease
of its molecular weight.
[0013] Although the patents mentioned above made certain improvements on the process related
to solvent and dissolving, the following problems still exist: the processing equipment
is complicated; the process is not stable. In addition, there is a safety risk associated
with the process, and the tenacity of so obtained fiber is decreased.
[0014] The fiber with high strength and high modulus can be obtained only after large amount
of the first solvent contained in the gel fiber is extracted with a second solvent
and the stretching of the gel fiber is performed. The extraction speed depends on
the second solvent used, the extraction process, as well as the diffusion path of
the solvent. During the course of the extraction, the solvent in the outer surface
of the fiber will first diffuse from the gel fiber. The longer the diffusion distance,
the bigger the difference in diffusion speeds. According to the current method, the
cross section of a PE gel fiber is round and has a thicker wall. The bigger the difference,
the easier to form a skin-core structure, which is not a homogeneous structure and
which has a negative influence on the stretching process so as to affect the mechanical
properties of the fiber product.
[0015] Currently, there are some patents related to the preparing of profiled HDPE fiber
membrane, including
US Patent Nos. 4115492,
5294338,
6436319 and
ZL200510049263, all of which use melting spinning; and
US Patent No. 5695702 and
ZL95193838, which use thermoplastic hollow fiber membrane module and method of manufacture.
The methods described therein above suffer the problem of high cost, while the homogeneity
of the fiber structure obtained is not satisfying.
[0016] Furthermore, the preparation of high strength and high modulus PE fiber by stretching
or drawing UHMWPE gel fiber has already been industrialized. The searched patents
for PE gel fiber include
EP 0205960A,
EP 0213208A1,
US Patent No. 4413110,
WO 01/73173A1, and
EP 1746187A1, which made some modifications on spinning technology. For the UHMWPE gel spinning
process, it is critical to obtain a homogeneous polymer solution and a stable drawing
of gel fiber. As a pre-condition for the formation of fiber with stable properties,
it is important to have a good solution and a stable drawing operation.
[0017] Because PE fiber has the advantages of light weight, flexible, high strength and
high modulus, UV-proof, anti-impact, and anti-corrosion to seawater, it can be used
for cutting-proof gloves, bullet-proof jacket or helmet, cable etc. In most circumstances,
one kind or several kinds of base materials, such as acrylonitrile butadiene rubber,
polyurethane and epoxy resin, can be combined with the PE fiber. Due to the inertia
surface of the PE fiber, the interface adhesion between the fiber and the base material
is poor, which has brought great attention of those skilled in this field. To improve
the interface adhesion strength between the fiber and the base resin, certain methods
of surface treatment, including surface grafting improving, chemical agent etching,
plasma processing, corona arc treatment, and photo-oxidation surface modification,
etc., have been used to activate the inertia surface of the PE fiber.
[0018] US Patent No. 480136 discloses that during spinning, thermal initiated surface silanization grafting reaction
occurs on PE fiber, with a further cross-linking process, and results in the improvement
of the adhesive property of the PE fiber. However, the process has a negative influence
on the subsequent drawing process, and the mechanical properties of the fiber is not
satisfying.
US 5039549,
US 5755913 and
ZL03115300.3 describe that plasma, ozone, corona arc or UV radiation can be used to improve the
adhesive property on PE fiber surface. However, these processes are complicated and
involve expensive equipment, and the process parameters are difficult to control.
Therefore, the processes are difficult to be industrialized.
[0019] Jiang Shen et al. proposes to use strong oxidizing agents, such as chromic acid,
kali permanganate, to etch the surface of the PE fiber (see,
UHMWPE Fiber Adhesive Property Study, Reinforced Glass/Complex Material, 2004(3):47). Because this method requires the merging of the PE fiber in a strong oxidation
environment for a long time, while the fiber infiltrating property may be improved,
the mechanical properties of the fiber is decreased. In addition, such processes are
also complicated, with a strict requirement on the equipment, and also have the pollution
problem from the waste liquid.
[0020] CN163544 proposes to use a composite extracting agent containing polar polymer compound to
treat the spinned PE gel fiber to improve the adhesive property on the fiber surface
while maximally maintaining the original strength of the fiber. This process is relatively
simple, without requiring any additional equipment. Although this process is efficient
for loose gel fiber, in practical production with tension extraction, it is difficult
for polar polymer compound to diffuse into gel fiber, and therefore, the improvement
made on the adhesive property is not apparent.
DESCRIPTION OF THE INVENTION
[0021] The present invention is to solve the existing technical problems in UHMWPE fiber
production, and specifically to solve the problem in the preparation of homogeneous
solution containing raw material, and in the removal of the first solvent from the
gel fiber. One objective of the present invention is to provide a simple, efficient
and low cost method to prepare the HMWPE fiber. The HMWPE fiber prepared by this method
has high adhesive property.
[0022] In particular, the technical problems can be solved by the following methods.
[0023] The method of preparing UHMWPE fiber comprises: mixing PE powder having a relative
average molecule weight (MW) of 1 million to 6 million with polar polymer in a solvent,
to form an emulsion mixture; the mixture being fed into an extruder with agitation,
where the mixture swells and dissolves rapidly to form a transparent and homogeneous
solution; and the solution being extruded through an spinnerette to spin into a gel
filament, followed by cooling, extraction, drying and stretching (or drawing) to produce
the desired UHMWPE fiber.
[0024] During the preparation of the emulsion mixture according to the present invention,
the PE powder having a relative MW of 1 million to 6 million is mixed with polar polymer
and solvent in an appropriate ratio, and the resulting mixture is fed into an untwisting
equipment to untwist, and thereby forming a uniform emulsion mixture.
[0025] The concentration of the above-mentioned uniform emulsion mixture is about 4% to
60% (wt).
[0026] The polar polymer mentioned above includes polar polymer containing ester group,
carbonyl group or ether group. The polar polymer containing ester group, carbonyl
group or ether group refers to ethylene/vinyl acetate co-polymer, polyacrylates, polyethylene
pyrrolidone /vinyl acetate co-polymer with different K value, polyoxyethylene polymer,
or mixtures thereof.
[0027] The added weight% for the polar polymer relative to the UHMWPE powder with relative
MW of 1 million to 6 million is about 1-10%, preferably about 2-8%.
[0028] In the untwisting process mentioned above, silicone oil or its derivative can be
used for untwisting. Additionally, silicone oil or its derivative can also be used
during the cooling (solidifying) process. Silicone oil or its derivative may comprise
about 0.05-5 wt% of the UHMWPE fiber.
[0029] During the untwisting process mentioned above, one or more antioxidant, stabilizer,
coloring agent, fire retardant can be added.
[0030] In the process mentioned above, the untwisting equipment may provide a cutting speed
of at least 1000S
-1, preferably 1000-5000 S
-1, and more preferably 2000-4000S
-1. The untwisting equipment mentioned above can be high-speed dispersion machine, agitator
(intensive mixing vessel), colloid mill, homogenizer, venturi, or any combinations
thereof.
[0031] In the method mentioned above, the preferred relative average MW for UHMWPE is 4
million to 6 million, and more preferably 2 million to 5 million.
[0032] In the process to prepare the uniform emulsion mixture according to the present invention,
the solvent used is liquid under room temperature, and it may be alkane (or paraffin)
or its derivative, cycloalkane (or cycloparaffin) or its derivative, aromatic hydrocarbon
or its derivative, or mixtures thereof.
[0033] In the process to prepare the homogeneous solution according to the present invention,
the nominal concentration for the UHMWPE and the solvent is 1-50 wt%.
[0034] The extruder used in the present invention includes single screw, double-screw, triple-screw
or four-screw extruder, where the extruding temperature is above the melting point
of the UHMWPE, for example, 80-250°C as the working temperature for the extruder.
[0035] The double-screw extruder can rotate in same direction or reverse direction, and
the screw's length/diameter ratio is 1:30-65.
[0036] In one embodiment of the present invention, the uniform emulsion mixture stays in
the double-screw extruder for 10-60 minutes (residence time), and preferably 20-40
minutes; with a material temperature inside the extruder at 50-280°C, and the extruding
temperature for gel spinning at 140-280°C, preferably at 200-260°C.
[0037] In another embodiment, the spinnerette of the extruder has a rectangle shape, with
a Length/Width ratio of 4-20, preferably 5-15.
[0038] In another embodiment, the emulsion mixture can be fed into the extruder directly,
or
via a storage vessel with an agitator (e.g., mixing vessel). The vessel can be one set
or more than two sets.
[0039] In the drawing (or stretching) process of this invention, the drawing temperature
for fiber is 80-130°C, at a draw ratio of more than 20/1, preferably 30/1-60/1.
[0040] Compared with existing technologies, the present invention has the following advantages:
1 UHMWPE fiber with PU or butyronitrile glove, is flexible and light, and has anti-corrosive,
anti-aging, and anti-oil properties, and is the best option for the preparation of
cutting-proof glove on the market. However, due to the inertia ofPE, the adhesive
interaction between PE and PU or PE and butyronitrile is poor. The present invention
utilizes a cutting untwisting process to prepare UHMWPE. In addition, polar polymer
containing ester group, carbonyl group and/or ether group is added to the UHMWPE.
As a result, the polar polymer is evenly distributed in the UHMWPE so as to provide
a PE fiber with high adhesive property. This process is simple and does not need any
additional equipment.
2 The emulsion mixture containing UHMWPE and a suitable amount of polar polymer undergo
high speed cutting, swelling as well as complete dissolving in a double screw extruder.
This is helpful to minimize the degradation of the polymer, and thereby improving
the adhesive property without affecting the mechanical property of the fiber.
3 In addition to the use of high speed cutting to untwist UHMWPE, a suitable amount
of carbon chain polar polymer containing polar side groups such as ester group, carbonyl
group or carboxy group can be added to improve the adhesive property of the PE without
affecting its rupture strength (tenacity).
4 The UHMWPE fiber prepared by the method of the present invention has high rupture
strength (tenacity) and strong energy absorption, and provides maximum rupture extension
(elongation) while maintaining enough rupture strength, which allows to achieve an
optimized balance between rupture strength and rupture extension. This material is
suitable for the preparation of cutting-proof glove. This invention uses rapid swelling
and dissolving of UHMWPE by a high speed cutting and untwisting process to ensure
that the rupture strength for the fiber is above 30CN/dtex with a rupture level of
more than 30030CN/dtex.
5 Usually, the fiber used in the cutting-proof glove has a single layer. In addition
to good cutting-proof performance, the glove is also required to be even and homogeneous
in density. This, it imposes a higher demand on fiber homogeneity. Currently, the
CV value for titer and strength of UHMWPE fiber is about 8-10%. The present invention
can achieve a CV value for titer and strength of the UHMWPE fiber at about 4-6%, by
utilizing rapid swelling and dissolving of UHMWPE and addition of a surface active
agent in a cooling (solidifying) solution, as well as the design of a flat filament
structure.
6 In accordance with the present invention, the UHMWPE fiber has a flat structure.
As a result, the specific surface area of the fiber is increased, which is beneficial
for solidifying evenly and shortening the distance for the diffusion of the solvent
from the gel fiber. Accordingly, this method can increase the extraction rate, reduce
the amount of the second solvent used in extraction and lower the cost, and also improve
the homogeneity and strength of the fiber.
7 Utilizing suitable untwisting, the method of the present invention not only makes
the process simple, saves cost, manpower and time, but also makes dissolving more
homogeneous.
SPECIFIC EMBODIMENTS
[0041] To facilitate the understanding of the technical approach, innovation characteristics,
and final results and functions of the present invention, the following examples are
provided to further illustrate the invention.
Example 1
[0042] UHMWPE (Relative Average Molecule Weight 4.5M) powder and #90 solvent white oil with
a weight ratio of 1:8, were fed into an untwisting pan at room temperature, and underwent
cutting for 10minutes at a speed of 2000S
-1 under N
2 protection, to form a homogeneous emulsion mixture. The mixture was fed into a same
directional double screw extruder (intake diameter = Φ25mm, Length/Diameter ratio
= 36, temperature = 250°C, the screw rotation speed = 35rpm). The extruded material
was filtered, and spun into a gel filament through a spinnerette, then extracted and
stretched at a stretch ratio of 35, to provide UHMWPE.
Example 2
[0043] UHMWPE (Relative Average Molecule Weight 4.5M) powder and #90 solvent white oil with
a weight ration of 1:8 were fed into an untwisting pan at room temperature, and further
added EVA28190 (ethylne-vinyl acetate co-polymer, with vinyl acetate comprising 28%,
melting index = 190) with an amount of 4 % by weight of the UHMWPE powder, and underwent
cutting for 10 minutes under N
2 protection at a speed of 2000S
-1, to form a homogeneous emulsion mixture. The mixture was fed into a same directional
double screw extruder (intake diameter = Φ25mm, Length/Diameter ratio = 36, temperature
= 250°C, the screw rotation speed = 35rpm). The extruded material was filtered, and
spun into a gel filament through a spinnerette, then extracted and stretched at a
draw ratio of 35, to produce UHMWPE with high adhesive properties.
Example 3
[0044] UHMWPE (Relative Average Molecule Weight 4.5M) powder and #90 solvent white oil with
weight ratio of 1:8 were fed into an untwisting pan at room temperature, and further
added EVA28190 (ethylene-vinyl acetate co-polymer, with vinyl acetate comprising 28%,
melting index = 190) with an amount of 2 % by weight of the UHMWPE powder, and underwent
cutting for 10 minutes under N
2 protection at a speed of 2000S
-1, to produce a homogeneous emulsion mixture. The mixture was fed into a same directional
double screw extruder (intake diameter = Φ25mm, Length/Diameter ratio = 36, temperature
= 250°C, the screw rotation speed = 35rpm). The extruded material was filtered, and
spun into a gel filament through a spinnerette, then extracted and stretched at a
draw ratio of 35, to produce UHMWPE with high adhesive properties.
Example 4
[0045] UHMWPE (Relative Average Molecule Weight 4.5M) powder, is mixed with #90 solvent
white oil with weight ratio of 1:8 were fed into an untwisting pan at room temperature,
and further added EVA1030 (ethylene-vinyl acetate co-polymer, with vinyl acetate comprising
10%, melting index = 30) with an amount of 4 % by weight of the UHMWPE powder, and
underwent cutting for 10 minutes under N
2 protection at a speed of 2000S
-1, to produce a homogeneous emulsion mixture. The mixture was fed into a same directional
double screw extruder (intake diameter = Φ25mm, Length/Diameter ratio = 36, temperature
= 250°C, the screw rotation speed = 35 rpm). The extruded material was filtered, and
spun into a gel filament through a spinnerette, then extracted and stretched at a
draw ratio of 35, to produce UHMWPE with high adhesive properties.
Example 5
[0046] UHMWPE (Relative Average Molecule Weight 4.5M) powder and #90 solvent white oil with
weight ratio of 1:8 were fed into an untwisting pan at room temperature, and further
added polyacrylate with an amount of 2 % by weight of the UHMWPE powder, and underwent
cutting for 10 minutes under N
2 protection at a speed of 2000S
-1, to produce a homogeneous emulsion mixture. The mixture was fed into a same directional
double screw extruder (intake diameter = Φ25mm, Length/Diameter ratio = 36, temperature
= 250°C, the screw rotation speed = 35rpm). The extruded material was filtered, and
spun into a gel filament through a spinnerette, then extracted and stretched at a
draw ratio of 35, to produce UHMWPE with high adhesive properties.
Example 6
[0047] UHMWPE (Relative Average Molecule Weight 4.5M) powder and #90 solvent white oil with
weight ratio of 1:8 were fed into an untwisting pan at room temperature, and further
added polyoxyethylene with an amount of 4 % by weight of the UHMWPE powder, and underwent
cutting for 10 minutes under N
2 protection at a speed of 2000S
-1, to form a homogeneous emulsion mixture. The mixture was fed into a same directional
double screw extruder (intake diameter = Φ25mm, Length/Diameter ratio = 36, temperature
= 250°C, the screw rotation speed = 35rpm). The extruded material was filtered, and
spun into a gel filament through a spinnerette, then extracted and stretched at a
draw ratio of 35, to produce UHMWPE with high adhesive properties.
[0048] The mechanical and adhesive properties of the UHMWPE fiber prepared according to
Example 1 (without the addition of polar polymer) and Example 2-6 are listed in Table
1.
Table 1. Mechanical Properties and Adhesive Strength of UHMWPE Fiber Prepared According
to This Invention
Example No. |
Rupture Strength (Tenacity) CN/dtex |
Young's Modulus CN/dtex |
Rupture Extension (Elongation) CN/dtex |
Pull-out Strength CN/dtex |
1 |
35.25 |
972 |
4.07 |
10.23 |
2 |
31.31 |
939 |
4.42 |
26.73 |
3 |
33.63 |
953 |
4.26 |
20.54 |
4 |
31.09 |
926 |
4.19 |
21.59 |
5 |
30.95 |
896 |
4.91 |
29.06 |
6 |
33.73 |
977 |
4.15 |
18.77 |
[0049] The following procedure is used to measure the adhesive strength of the UHMWPE fiber:
The UHMWPE fiber is passed through a capsule with small hole, the height of the capsule
being about 7mm. An epoxy resin and a solidifying agent are mixed at a ratio of 4:1,
and charged into the capsule, and allow for solidifying for 48 hours. The embedded
length L(mm) of the fiber in the capsule is measured, using a pull-out experiment,
which utilizes DXLL-20000 Strong Power Device to measure the adhesive properties between
the UHMWPE fiber and epoxy resin (clamping distance = 200mm; dropping speed = 50 mm/min.;
and the pull-out strength of the fiber can be calculated by the following formula:
Pull-out strength = tested strength * 7 /L.
Example 7
[0050] UHMWPE (Relative Average Molecule Weight 4.5M) powder and #90 solvent white oil with
a nominal concentration of 10% (wt) were fed into an untwisting pan at room temperature,
and underwent cutting for 5 minutes under N
2 protection at a speed of 3000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a same directional double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 45, temperature
= 250°C, the screw rotation speed = 35rpm). The extruded material passed through a
filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath, followed by extraction, drying
and stretching at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength
(i.e., Tenacity) of 30cN/dtex and Young's Modulus of over 1000cN/dtex.
Example 8
[0051] UHMWPE (Relative Average Molecule Weight 5 M) powder and #90 solvent white oil with
a nominal concentration of 5% (wt) were fed into an untwisting pan at room temperature,
and underwent cutting for 5 minutes under N
2 protection at a speed of 3000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 64, temperature
= 250°C, screw rotation speed = 50 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath, followed by extraction, drying
and stretching at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength
of 28cN/dtex and Young's Modulus of over 900cN/dtex.
Example 9
[0052] UHMWPE (Relative Average Molecule Weight 4.5 M) powder and #90 solvent white oil
with a nominal concentration of 5% (wt) were fed into an untwisting pan at room temperature,
and further added 0.2% (wt) of an anti-oxidant, and underwent cutting for 5 minutes
under N
2 protection at a speed of 2000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 240°C, screw rotation speed = 50 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath, followed by extraction, drying
and stretching at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength
of 28cN/dtex and Young's Modulus of over 900cN/dtex.
Example 10
[0053] UHMWPE (Relative Average Molecule Weight 5 M) powder and #90 solvent white oil with
a nominal concentration of 12% (wt) were fed into an untwisting pan at room temperature,
and underwent cutting for 10 minutes under N
2 protection at a speed of 2000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 250°C, screw rotation speed = 30 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath, followed by extraction, drying
and stretching at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength
of 35cN/dtex and Young's Modulus of over 1050cN/dtex.
Example 11
[0054] UHMWPE (Relative Average Molecule Weight 4.5 M) powder and #90 solvent white oil
with a nominal concentration of 10% (wt) were fed into an untwisting pan at room temperature
via a spiral propeller at a speed of 0.5kg/min, and underwent cutting under N
2 protection at a speed of 1000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 250°C, screw rotation speed = 30 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath containing 2% polyether-epoxy modified
silicone oil, followed by extraction, drying and stretching at a draw ratio of 40,
to produce UHMWPE fiber with Rupture Strength of 30cN/dtex and Young's Modulus of
over 1000cN/dtex.
Example 12
[0055] UHMWPE (Relative Average Molecule Weight 4.5 M) powder and #70 solvent white oil
with a nominal concentration of 12% (wt) were fed into an untwisting pan at room temperature,
and underwent cutting for 15 minutes under N
2 protection at a speed of 1000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 250°C, screw rotation speed = 30 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath, followed by extraction, drying
and stretching at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength
of 30cN/dtex and Young's Modulus of over 1000cN/dtex.
Example 13
[0056] UHMWPE (Relative Average Molecule Weight 4.5 M) powder and #70 solvent white oil
with a nominal concentration of 10% (wt) were fed into an untwisting pan at room temperature,
and further added 1% (wt) of epoxy modified silicone oil, and underwent cutting for
5 minutes under N
2 protection at a speed of 3000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 250°C, screw rotation speed = 50 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath, followed by extraction, drying
and stretching at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength
of 30cN/dtex and Young's Modulus of over 1000cN/dtex.
Example 14
[0057] UHMWPE (Relative Average Molecule Weight 5 M) powder and #90 solvent white oil with
a nominal concentration of 12% (wt) were fed into an untwisting pan at room temperature,
and underwent cutting for 10 minutes under N
2 protection at a speed of 2000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 250°C, screw rotation speed = 30 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath containing 1.5wt% of epoxy modified
silicone oil, followed by extraction, drying and stretching at a draw ratio of 40,
to produce UHMWPE fiber with Rupture Strength of 35cN/dtex and Young's Modulus of
over 1050cN/dtex.
Example 15
[0058] UHMWPE (Relative Average Molecule Weight 4.5 M) powder and #90 solvent white oil
with a nominal concentration of 10% (wt) were fed into an untwisting pan at room temperature
via a spiral propeller at a speed of 0.5kg/min, and underwent cutting under N
2 protection at a speed of 1000S
-1, to form a homogeneous emulsion mixture. The mixture, with agitation, was fed into
a double screw extruder
via a storage vessel (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 250°C, screw rotation speed = 30 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette, passed through a water bath containing 2% polyether-epoxy modified
silicone oil, followed by extraction, drying and stretching at a draw ratio of 30,
to produce UHMWPE fiber with Rupture Strength of 30cN/dtex and Young's Modulus of
over 1000cN/dtex.
Example 16
[0059] UHMWPE (Relative Average Molecule Weight 4.5 M) powder and solvent white oil were
mixed to prepare a homogeneous solution with a concentration of 8% (wt) and fed into
a double screw extruder (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 240°C, screw rotation speed = 30 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette comprising apertures having a rectangular shape with a Length/Width
ratio of 8, passed through a water bath, followed by extraction, drying and stretching
at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength of 30cN/dtex
and Young's Modulus of over 1000cN/dtex.
Example 17
[0060] UHMWPE (Relative Average Molecule Weight 4.5 M) powder and solvent white oil were
mixed to prepare a homogeneous solution with a concentration of 10% (wt) and fed into
a double screw extruder (extruder diameter = Φ25mm, Length/Diameter ratio = 24, temperature
= 250°C, screw rotation speed = 40 rpm). The extruded material was passed through
a filter tank and a metering pump to get a measurement, and spun into a gel filament
through a spinnerette comprising apertures having a rectangular shape with a Length/Width
ratio of 12, passed through a water bath, followed by extraction, drying and stretching
at a draw ratio of 40, to produce UHMWPE fiber with Rupture Strength of 30cN/dtex
and Young's Modulus of over 1000cN/dtex.
[0061] The above descriptions demonstrate the basic principles, main characteristics and
advantages of the present invention. It should be understood by one of ordinary skill
in the art that the present invention is not limited by the examples described hereinabove.
The examples and descriptions described herein only illustrate the principles for
this invention, and various changes and modifications may be made without departing
from the spirit and scope of the present invention. Such changes and modifications
are included in the scope of this invention. The claimed scope of the present invention
is further illustrated by the appended claims and equivalents thereof.
1. A method to prepare UHMWPE fiber, characterized in that: UHMWPE powder having a relative average molecular weight of 1 million to 6 million
is added with polar polymer and dispersed in a solvent to form an uniform emulsion
mixture, using gel spinning, the mixture is fed gradually and with agitation into
an extruder wherein the mixture swells and dissolves to form a transparent and homogeneous
solution, the solution being extruded through a spinnerette to spin into a gel filament,
followed by cooling, solidifying, extraction, drying and stretching to provide the
UHMWPE fiber.
2. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: during the preparation of the uniform emulsion mixture, the UHMWPE powder with relative
MW 1 million to 6 million, the polar polymer and the solvent are mixed in a suitable
ratio and fed into an untwisting equipment to untwist to form the uniform emulsion
mixture.
3. The method to prepare UHMWPE fiber according to Claim 1 or Claim 2, characterized in that: the concentration of the uniform emulsion mixture is 4%-60%.
4. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the polar polymer is polar polymer comprising an ester group, a carbonyl group or
an ether group.
5. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the polar polymer comprising an ester group, a carbonyl group or an ether group is
selected from ethylene/vinyl acetate co-polymer, polyacrylates, polyethylene pyrrolidone/vinyl
acetate co-polymer, polyoxyethylene polymer and mixtures thereof.
6. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the amount of the polar polymer relative to the UHMWPE powder is 1-10% by weight.
7. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the amount of the polar polymer relative to the UHMWPE powder is 2-8% by weight.
8. The method to prepare UHMWPE fiber according to Claim 2, characterized in that: during the untwisting process, silicone oil or its derivative is added for untwisting;
and/or during solidifying process, silicone oil or its derivative is added; in which
the silicone oil or its derivative comprises 0.05-5% by weight of the UHMWPE fiber.
9. The method to prepare UHMWPE fiber according to Claim 8, characterized in that: one or more selected from an antioxidant, a stabilizer, a coloring agent and a fire
retardant is added during the untwisting process.
10. The method to prepare UHMWPE fiber according to Claim 2, characterized in that: the untwisting equipment provides a cutting speed of at least 1000S-1.
11. The method to prepare UHMWPE fiber according to Claim 10, characterized in that: the untwisting equipment provides a cutting speed of 1000 to 5000S-1.
12. The method to prepare UHMWPE fiber according to Claim 10, characterized in that: the untwisting equipment provides a cutting speed of 2000 to 4000S-1.
13. The method to prepare UHMWPE fiber according to Claim 2, characterized in that: the untwisting equipment is selected from high-speed dispersion machine, mixer,
colloid mill, homogenizer, venturi, and combinations thereof.
14. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the UHMWPE has a relative average molecular weight of 4 million to 6 million.
15. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the UHMWPE has a relative average molecular weight of about 2 million to 5 million.
16. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the solvent used to form an uniform emulsion mixture is in liquid form at room temperature,
and is selected from alkane hydrocarbon or its derivative, cycloalkane hydrocarbon
or its derivative, aromatic hydrocarbon or its derivative, and mixtures thereof.
17. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: during the preparation of the uniform emulsion mixture, the nominal concentration
of the UHMWPE powder in the solvent is about 1-50wt%.
18. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the extruder is selected from a single screw extruder, a double-screw extruder, a
three-screw extruder, and a four-screw extruder, and the operating temperature for
the extruder is 80-250°C.
19. The method to prepare UHMWPE fiber according to Claim 18, characterized in that: the double-screw extruder can rotate in same direction or reverse direction, and
the Length/Diameter ratio of the screw rod is 1:30-65.
20. The method to prepare UHMWPE fiber according to Claim 19, characterized in that: the residence time for the uniform emulsion mixture in the double-screw extruder
is 10-60 minutes, preferably 20-40 minutes; material temperature is 50-280°C, and
the temperature of the extruded gel filament is 140-280°C, preferably 200-260°C.
21. The method to prepare UHMWPE fiber according to Claim 20, characterized in that: the residence time for the uniform emulsion mixture in the double-screw extruder
is 20-40 minutes, and the temperature of the extruded gel filament is 200-260°C.
22. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the spinnerette of the extruder comprises apertures having a rectangle shape with
a Length/Width ratio of 4:20.
23. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the Length/Width ratio is 5:15.
24. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the emulsion mixture can be fed into the extruder directly or via a storage vessel equipped with an agitator.
25. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the stretching is conducted at a temperature of 80-130°C and at a draw ratio of at
least 20/1.
26. The method to prepare UHMWPE fiber according to Claim 25, characterized in that: the draw ratio is from 30/1 to 60/1 for stretching.
Amended claims under Art. 19.1 PCT
1. A method to prepare UHMWPE fiber, characterized in that: UHMWPE powder having a relative average molecular weight of 1 million to 6 million
is added with polar polymer and dispersed in a solvent to form an uniform emulsion
mixture, using gel spinning, the mixture is fed gradually and with agitation into
an extruder wherein the mixture swells and dissolves to form a transparent and homogeneous
solution, the solution being extruded through a spinnerette to spin into a gel filament
wherein the spinnerette comprises apertures having a shape of rectangle, followed
by cooling, solidifying, extraction, drying and stretching to provide the UHMWPE fiber.
2. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: during the preparation of the uniform emulsion mixture, the UHMWPE powder with relative
MW 1 million to 6 million, the polar polymer and the solvent are mixed in a suitable
ratio and fed into an untwisting equipment to untwist to form the uniform emulsion
mixture.
3. The method to prepare UHMWPE fiber according to Claim 1 or Claim 2, characterized in that: the concentration of the uniform emulsion mixture is 4%-60%.
4. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the polar polymer is polar polymer comprising an ester group, a carbonyl group or
an ether group.
5. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the polar polymer comprising an ester group, a carbonyl group or an ether group is
selected from ethylene/vinyl acetate co-polymer, polyacrylates, polyethylene pyrrolidone/vinyl
acetate co-polymer, polyoxyethylene polymer and mixtures thereof.
6. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the amount of the polar polymer relative to the UHMWPE powder is 1-10% by weight.
7. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the amount of the polar polymer relative to the UHMWPE powder is 2-8% by weight.
8. The method to prepare UHMWPE fiber according to Claim 2, characterized in that: during the untwisting process, silicone oil or its derivative is added for untwisting;
and/or during solidifying process, silicone oil or its derivative is added; in which
the silicone oil or its derivative comprises 0.05-5% by weight of the UHMWPE fiber.
9. The method to prepare UHMWPE fiber according to Claim 8, characterized in that: one or more selected from an antioxidant, a stabilizer, a coloring agent and a fire
retardant is added during the untwisting process.
10. The method to prepare UHMWPE fiber according to Claim 2, characterized in that: the untwisting equipment provides a cutting speed of at least 1000S-1.
11. The method to prepare UHMWPE fiber according to Claim 10, characterized in that: the untwisting equipment provides a cutting speed of 1000 to 5000S-1.
12. The method to prepare UHMWPE fiber according to Claim 10, characterized in that: the untwisting equipment provides a cutting speed of 2000 to 4000S-1.
13. The method to prepare UHMWPE fiber according to Claim 2, characterized in that: the untwisting equipment is selected from high-speed dispersion machine, mixer, colloid
mill, homogenizer, venturi, and combinations thereof.
14. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the UHMWPE has a relative average molecular weight of 4 million to 6 million.
15. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the UHMWPE has a relative average molecular weight of about 2 million to 5 million.
16. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the solvent used to form an uniform emulsion mixture is in liquid form at room temperature,
and is selected from alkane hydrocarbon or its derivative, cycloalkane hydrocarbon
or its derivative, aromatic hydrocarbon or its derivative, and mixtures thereof.
17. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: during the preparation of the uniform emulsion mixture, the nominal concentration
of the UHMWPE powder in the solvent is about 1-50wt%.
18. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the extruder is selected from a single screw extruder, a double-screw extruder, a
three-screw extruder, and a four-screw extruder, and the operating temperature for
the extruder is 80-250°C.
19. The method to prepare UHMWPE fiber according to Claim 18, characterized in that: the double-screw extruder can rotate in same direction or reverse direction, and
the Length/Diameter ratio of the screw rod is 1:30-65.
20. The method to prepare UHMWPE fiber according to Claim 19, characterized in that: the residence time for the uniform emulsion mixture in the double-screw extruder
is 10-60 minutes, preferably 20-40 minutes; material temperature is 50-280°C, and
the temperature of the extruded gel filament is 140-280°C, preferably 200-260°C.
21. The method to prepare UHMWPE fiber according to Claim 20, characterized in that: the residence time for the uniform emulsion mixture in the double-screw extruder
is 20-40 minutes, and the temperature of the extruded gel filament is 200-260°C.
22. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the spinnerette of the extruder comprises apertures having a rectangle shape with
a Length/Width ratio of 4:20.
23. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the Length/Width ratio is 5:15.
24. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the emulsion mixture can be fed into the extruder directly or via a storage vessel
equipped with an agitator.
25. The method to prepare UHMWPE fiber according to Claim 1, characterized in that: the stretching is conducted at a temperature of 80-130°C and at a draw ratio of at
least 20/1.
26. The method to prepare UHMWPE fiber according to Claim 25, characterized in that: the draw ratio is from 30/1 to 60/1 for stretching.