An ultra-high molecular weight polyethylene fiber having self-lubricating properties, a method for manufacturing the same, and applications thereof

Abstract

The present application relates to a kind of ultra-high molecular weight polyethylene fibers with self-lubricating properties, its manufacturing method and its application.The manufacturing method of the ultra-high molecular weight polyethylene fiber of the present application includes the following steps: 1) mixing ultra-high molecular weight polyethylene, polyethylene wax and solvent to prepare spinning solution, 2) the spinning solution is extruded through spinneret to form spinning stream, 3) while stretching the spinning stream, at least a part of the solvent is removed from the spinning stream, and the ultra-high molecular weight polyethylene fiber is obtained, wherein the ratio of the stretching speed of the spinning stream to the extrusion speed is 1-20.The present application adds polyethylene wax, by controlling its migration in the process of fiber forming, to form a lubricating layer on the surface of the fiber automatically, and to improve the friction resistance of the fiber.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-performance fibers, in particular, to an ultra-high molecular weight polyethylene fiber with self-lubricating properties, a manufacturing method thereof and applications thereof. BACKGROUND

[0002] Due to the difference of solvent process, the cross section of dry-spun ultra-high molecular weight polyethylene fiber presents irregular bean-shaped, waist-shaped and other irregular structures. In addition, the fiber is thin, and the surface is easily scratched and damaged in the process of production and use. The fiber forms debris in the position of friction parts, which causes cleaning difficulties. Especially in the field of knitting, the debris accumulates, which can cause problems such as porcelain blockage and fabric defects, affecting its application and promotion.

[0003] Generally, the improvement of this problem in the art is achieved by surface coating of oil agent during processing. However, the method of coating oil agent has the following problems: 1. The adhesion of oil agent to the simple and dense structure of ultra-high molecular weight polyethylene is not good, and the effect is not ideal; 2. The oil film is not uniform, which leads to the failure of full-process protection; 3. The oil agent will be damaged and its performance will be reduced in the process of high-temperature heating and high-drafting in production; 4. The strength of the oil film is not high, and it will quickly fail in the process of continuous friction. The present application discards this idea and takes a different approach by adding polyethylene wax, which is a similar compatible material, in the spinning process. The migration of polyethylene wax to the surface is controlled through process design, forming a self-lubricating layer with excellent compatibility with the fiber, thereby improving the friction resistance of the fiber and solving the problem of debris generated by fiber friction. SUMMARY

[0004] The present application aims to solve the problem of ultra-high molecular weight polyethylene fiber in the prior art, which is not resistant to wear and tear during friction, resulting in many application defects in the field of knitting and other fields. The present application provides a high-friction-resistant ultra-high molecular weight polyethylene fiber with self-lubricating properties. In the fiber forming process of the present application, decalin is a good solvent for ultra-high molecular weight polyethylene, which dissolves polyethylene to form a spinning solution at high temperature. The basic molecular weight structure unit of polyethylene wax is the same as that of ultra-high molecular weight polyethylene, so it has very good compatibility and will form a uniform solution with decalin. During the process of solvent evaporation to form the primary fiber, the polyethylene wax has very low molecular weight and good flowability, which will quickly migrate to the surface of the fiber during the evaporation process of the solvent. Then the primary fiber is stretched at a temperature of 90-160℃, which is higher than the melting point of polyethylene wax. Therefore, the polyethylene wax on the surface of the fiber is in a molten liquid state, which flows with the fiber during stretching, forming a uniform self-lubricating layer, thereby achieving the purpose of protecting the fiber and improving lubrication, and obtaining a high-friction-resistant ultra-high molecular weight polyethylene fiber.

[0005] Specifically, the present application relates to the following aspects.

[0006] 1. A process for producing an ultra-high molecular weight polyethylene fiber, comprising the steps of:

[0007] 1) mixing an ultra-high molecular weight polyethylene, a polyethylene wax and a solvent to form a dope,

[0008] 2) extruding the dope through a spinneret to form a spinning stream,

[0009] 3) simultaneously with drawing the spinning stream, removing at least a portion (such as at least 50 wt%, preferably at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt% or at least 97 wt%) of the solvent from the spinning stream to obtain the ultra-high molecular weight polyethylene fiber (referred to as a nascent fiber),

[0010] wherein the ratio of the drawing speed to the extrusion speed of the spinning stream is 1-20 (preferably 2-10).

[0011] 2. The process according to any of the preceding or following aspects, wherein in step 1) the polyethylene wax is used in an amount of 0.5-20 parts by weight (preferably 1-10 parts by weight) and the solvent is used in an amount of up to 2000 parts by weight (preferably 1000-1500 parts by weight) per 100 parts by weight of the ultra-high molecular weight polyethylene.

[0012] 3. The process according to any of the preceding or following aspects, wherein in step 1) the solvent is selected from at least one of naphthalene and its hydrogenated derivatives decalin, tetralin, kerosene, xylene, toluene, petroleum fractions, halogenated hydrocarbons, cycloalkanes, cycloalkenes, preferably decalin.

[0013] 4. The process according to any of the preceding or following aspects, wherein in step 1) the ultra-high molecular weight polyethylene has a viscosity average molecular weight of 1 million to 9 million (preferably 3 million to 5 million) and the polyethylene wax has a viscosity average molecular weight of 1000 to 5000 (preferably 1500 to 3000).

[0014] 5. The process according to any of the preceding or following aspects, wherein in step 1) the polyethylene wax has an intrinsic viscosity of 0.05 to 0.3 g / dl (preferably 0.1 to 0.2 g / dl) and the ultra-high molecular weight polyethylene has an intrinsic viscosity of 10 to 45 g / dl (preferably 15 to 35 g / dl).

[0015] 6. The process according to any of the preceding or following aspects, wherein in step 2) the extrusion temperature is 130 to 220 °C (preferably 150 to 180 °C) and the extrusion speed is 2 to 20 m / min (3 to 10 m / min).

[0016] 7. The production method according to any one of the preceding or following aspects, wherein the step 3) is performed immediately after the spinning stream leaves the spinneret.

[0017] 8. The production method according to any one of the preceding or following aspects, wherein in step 3) the operating conditions include: temperature of 70-180°C (preferably 100-140°C), blowing height of not less than 0.2 m (preferably 1-8 m), air volume of 50-180 m3 / h (preferably 60-100 m3 / h).

[0018] 9. The production method according to any one of the preceding or following aspects, wherein in step 3) the drawing speed is 2 m / min or more (preferably 5-15 m / min) and the draw ratio is not less than 2 (preferably 3-10).

[0019] 10. The production method according to any one of the preceding or following aspects, wherein in step 3) the drawing is performed simultaneously with the solvent removal and the elapsed time is not less than 2 min (preferably 3-10 min).

[0020] 11. The production method according to any one of the preceding or following aspects, wherein after the end of step 3) the nascent fiber is drawn in one or more stages (such as 1-8 or 2-5 stages) (referred to as post-drawing).

[0021] 12. The production method according to any one of the preceding or following aspects 1, wherein the operating conditions of the post-drawing include: drawing temperature of 90-160°C (preferably 120-140°C), (total) draw ratio of 2-30 (preferably 10-15).

[0022] 13. An ultra-high molecular weight polyethylene fiber obtained by the production method according to any one of the preceding or following aspects.

[0023] 14. The ultra-high molecular weight polyethylene fiber according to any one of the preceding or following aspects, having a core and a self-lubricating layer covering at least a part (preferably substantially all) of the surface of the core.

[0024] 15. The ultra-high molecular weight polyethylene fiber according to any one of the preceding or following aspects, wherein the self-lubricating layer has polyethylene wax as a main component.

[0025] 16. The ultra-high molecular weight polyethylene fiber according to any one of the preceding or following aspects, wherein the self-lubricating layer is generated in situ.

[0026] 17. The ultra-high molecular weight polyethylene fiber according to any one of the preceding or following aspects, having a filament fineness of 0.7-5 dtex (preferably 1.7-2.7 dtex).

[0027] 18. The UHMWPE fiber according to any one of the preceding or following aspects, having a coefficient of friction of 0.05-0.30 (preferably 0.08-0.1) and a breaking strength of 10-45 cN / dtex (preferably 25-40 cN / dtex).

[0028] 19. A fabric comprising or made of the UHMWPE fiber according to any one of the preceding or following aspects.

[0029] 20. The fabric according to any one of the preceding or following aspects, further comprising at least one other fiber selected from the group consisting of natural plant fibers, natural animal fibers, man-made regenerated fibers, synthetic fibers and inorganic fibers.

[0030] Technical effects

[0031] The present application adds polyethylene wax, which forms a lubricating layer on the surface of the fiber by controlling its migration during the fiber forming process, thereby improving the fiber's resistance to friction. The breaking strength of the fiber obtained by the present application is 10-40 cN / dtex, and the fiber produced will not produce shedding during the production operation, weaving, knitting, etc. The coefficient of friction of the fiber is 0.05μ-0.30μ. The resistance to friction of the fiber is more than 1 times higher than that of ordinary dry spinning UHMWPE fiber. The fiber can be used in various fields such as gloves, outerwear, underwear, woven fabrics, knitted fabrics, ropes, threads, nets, etc. DETAILED DESCRIPTION

[0032] The specific embodiments of the present application are described in detail below, but it should be noted that the scope of protection of the present application is not limited by these specific embodiments, but is determined by the claims of the appendix.

[0033] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present specification, including definitions, will control.

[0034] When the specification uses phrases such as "known to those skilled in the art", "prior art", or similar phrases to derive materials, substances, methods, steps, devices or components, etc., the objects derived by the phrases cover those commonly used in the art at the time of filing the present application, but also include those not commonly used at present, but will be recognized as suitable for similar purposes in the art.

[0035] In the context of the present application, all numerical values of a parameter (e.g. a quantity or a condition) should be understood as being modified in all instances by the term "about", whether or not the term "about" is expressly recited before the numerical value.

[0036] In the context of the present application, the measurement method of breaking strength and breaking elongation is GB / T 19975.

[0037] In the context of the present application, the measurement method of filament fineness is GB / T 14343.

[0038] In the context of the present application, the friction coefficient test is performed on an USTER ZWEIGLE FRICTION TESTER 5 friction tester, and the friction resistance test is performed on a filament friction tester LY109D, with a weight of 100 g.

[0039] In the context of the present application, the shed situation is characterized by cumulative weighing, recording the weight of the shed when the fibers run for 8 hours in weaving into gloves.

[0040] In the absence of explicit indication, all percentages, parts, ratios, etc. mentioned in the present specification are based on weight, and the pressure is gauge pressure.

[0041] In the context of the present application, any two or more embodiments or aspects of the present application can be combined arbitrarily, and the technical solutions formed thereby belong to the part of the original disclosure of the present specification and also fall within the protection scope of the present application.

[0042] According to one embodiment of the present application, a manufacturing method of an ultra-high molecular weight polyethylene fiber is provided. According to the present application, the ultra-high molecular weight polyethylene fiber has a core and a self-lubricating layer covering at least a part of (preferably substantially all of) the surface of the core, thereby having self-lubricating properties. Moreover, the self-lubricating layer is generated in situ, i.e. the self-lubricating layer is directly generated during the manufacturing process of the ultra-high molecular weight polyethylene fiber, and is not additionally attached to the fiber by coating or the like.

[0043] According to one embodiment of the present application, the self-lubricating layer has polyethylene wax as the main component.

[0044] According to one embodiment of the present application, the manufacturing method comprises a step 1) of mixing ultra-high molecular weight polyethylene, polyethylene wax and solvent to prepare a spinning solution.

[0045] According to one embodiment of the present application, in step 1), the amount of polyethylene wax is 0.5-20 parts by weight (preferably 1-10 parts by weight) relative to 100 parts by weight of the ultra-high molecular weight polyethylene.

[0046] According to one embodiment of the present application, in step 1), the amount of solvent is at most 2000 parts by weight (preferably 1000-1500 parts by weight) relative to 100 parts by weight of the ultra-high molecular weight polyethylene.

[0047] According to one embodiment of the present invention, in step 1), the solvent is selected from at least one of naphthalene and its hydrogenated derivatives, decahydronaphthalene, tetrahydronaphthalene, kerosene, xylene, toluene, petroleum fractions, halogenated hydrocarbons, cycloalkanes, and cycloolefins, preferably decahydronaphthalene.

[0048] According to one embodiment of the present invention, in step 1), the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 1 million to 9 million (preferably 3 million to 5 million).

[0049] According to one embodiment of the present invention, in step 1), the viscosity-average molecular weight of the polyethylene wax is 1000-5000 (preferably 1500-3000).

[0050] According to one embodiment of the present invention, in step 1), the intrinsic viscosity of the polyethylene wax is 0.05-0.3 g / dl (preferably 0.1-0.2 g / dl).

[0051] According to one embodiment of the present invention, in step 1), the intrinsic viscosity of the ultra-high molecular weight polyethylene is 10-45 g / dl (preferably 15-35 g / dl).

[0052] According to one embodiment of the present invention, the manufacturing method includes step 2, which involves extruding the spinning solution through a spinneret to form a spinning stream.

[0053] According to one embodiment of the present invention, in step 2), the extrusion temperature is 130-220°C (preferably 150-180°C), and the extrusion speed is 2-20 m / min (3-10 m / min).

[0054] According to one embodiment of the invention, the ratio of the stretching speed to the extrusion speed of the spinning stream is 1-20 (preferably 2-10). This step promotes the diffusion of polyethylene wax to the surface. If this ratio is too high, it will lead to a decrease in fiber strength or even prevent continuous production; if this ratio is too low, it will prevent the polyethylene wax from migrating to the surface quickly or even prevent continuous spinning.

[0055] According to one embodiment of the invention, the manufacturing method includes step 3) of removing at least a portion of the solvent from the spun yarn while stretching the yarn, to obtain the ultra-high molecular weight polyethylene fiber (referred to as nascent fiber). If solvent removal is not performed during the stretching process, a solvent concentration gradient from the surface to the inner layer cannot be formed, and therefore the polyethylene wax cannot migrate to the surface. Here, "at least a portion" means, for example, at least 50 wt%, preferably at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or at least 97 wt%.

[0056] According to one embodiment of the present application, the step 3) is performed immediately after the spinning stream leaves the spinneret.

[0057] According to one embodiment of the present application, in the step 3), the operating conditions include: temperature of 70-180°C (preferably 100-140°C), blowing height of no less than 0.2m (preferably 1-8m), air volume of 50-180m3 / h (preferably 60-100m3 / h).

[0058] According to one embodiment of the present application, in the step 3), the drawing speed is 2m / min (preferably 5-15m / min), and the draw ratio is no less than 2 (preferably 3-10).

[0059] According to one embodiment of the present application, in the step 3), the drawing is performed synchronously with the solvent removal, and the time duration is no less than 2min (preferably 3-10min).

[0060] According to one embodiment of the present application, after the end of the step 3), the nascent fiber is drawn in one or more stages (such as 1-8 or 2-5 stages), which is referred to as post-drawing.

[0061] According to one embodiment of the present application, the operating conditions of the post-drawing include: drawing temperature of 90-160°C (preferably 120-140°C), (total) draw ratio of 2-30 (preferably 10-15).

[0062] According to one embodiment of the present application, it relates to an ultra-high molecular weight polyethylene fiber obtained by the manufacturing method according to any of the preceding or subsequent aspects of the present specification.

[0063] According to one embodiment of the present application, the single-fiber fineness of the ultra-high molecular weight polyethylene fiber is 0.7-5dtex (preferably 1.7-2.7dtex).

[0064] According to one embodiment of the present application, the coefficient of friction of the ultra-high molecular weight polyethylene fiber is 0.05-0.15 (preferably 0.08-0.1).

[0065] According to one embodiment of the present application, the breaking strength of the ultra-high molecular weight polyethylene fiber is 20-45cN / dtex (preferably 25-40cN / dtex).

[0066] According to one embodiment of the present application, it also relates to a fabric comprising or made of the ultra-high molecular weight polyethylene fiber according to any of the preceding or subsequent aspects of the present specification.

[0067] According to one embodiment of the present application, the fabric further comprises at least one other fiber selected from the group consisting of natural plant fibers, natural animal fibers, man-made regenerated fibers, synthetic fibers and inorganic fibers.

[0068] Examples

[0069] The present application is further illustrated in detail by the following examples and comparative examples, but the present application is not limited to these examples.

[0070] Example 1

[0071] An ultra-high molecular weight polyethylene fiber having self-lubricating properties according to the present embodiment is obtained by the following process:

[0072] Ultra-high molecular weight polyethylene with a viscosity average molecular weight of 4.5 million, polyethylene wax with a viscosity average molecular weight of 2,000 and decalin are mixed in a ratio of 100:2:1300 to swell. The ultra-high molecular weight polyethylene has an intrinsic viscosity of 25 g / dl and the polyethylene wax has an intrinsic viscosity of 0.15 g / dl. After the suspension is formed, it is dissolved by screw shearing, and extruded to form a spinning stream at 170°C at an extrusion speed of 3.5 m / min. Immediately after leaving the spinneret, the spinning stream is subjected to solvent removal, removing at least 98% of the solvent. The temperature is 135°C, the blowing height is 7.5 m, and the air volume is 90 m3 / h. The drawing speed is 12 m / min, the drawing ratio is 3.4, and the drawing is synchronized with the solvent removal, and the drawing time is 8 min, forming a primary yarn. The primary yarn is drawn in three stages, the drawing temperature is 130°C, and the drawing ratio is 13, to produce a finished yarn.

[0073] Example 2

[0074] The same as Example 1, except that the viscosity average molecular weight of the polyethylene wax is 800.

[0075] Example 3

[0076] The same as Example 1, except that the viscosity average molecular weight of the polyethylene wax is 8,000.

[0077] Example 4

[0078] The same as Example 1, except that the proportion of polyethylene wax is 0.2% (based on the weight of the ultra-high molecular weight polyethylene).

[0079] Example 5

[0080] The same as Example 1, except that the proportion of polyethylene wax is 30% (based on the weight of the ultra-high molecular weight polyethylene).

[0081] Example 6

[0082] The same as Example 1, except that the solvent removal time is 1 min.

[0083] Example 7

[0084] The same as Example 1 except that the ratio of decalin to solvent is 2000.

[0085] Example 8

[0086] The same as Example 1 except that the ratio of draw speed to extrusion speed of the spinning stream is 10.

[0087] Example 9

[0088] The same as Example 1 except that the ratio of draw speed to extrusion speed of the spinning stream is 2.

[0089] Example 10

[0090] The same as Example 1 except that the solvent temperature is 100°C, the blow height is 1 m, and the air volume is 50 m3 / h.

[0091] Comparative Example 1

[0092] The same as Example 1 except that a gel spinning process is used. Instead of immediately removing the solvent after the dope exits the spinneret, the dope is first cooled. The cooling temperature is 30°C and the cooling time is < 1 min.

[0093] Comparative Example 2

[0094] The same as Example 1 except that the extrusion speed is 0.3 m / min and the solvent removal draw speed is 0.5 m / min.

[0095] Comparative Example 3

[0096] The same as Example 1 except that the solvent removal and drawing are not performed simultaneously. Instead, the drawing step is performed first, followed by the solvent removal step.

[0097] Comparative Example 4

[0098] The same as Example 1 except that the solvent removal and drawing are not performed simultaneously. Instead, the solvent removal step is performed first, followed by the drawing step.

[0099] Comparative Example 5

[0100] The fiber is commercially available Fortron LY25 400D ultra-high molecular weight polyethylene fiber.

[0101]

Claims

1. A method for manufacturing ultra-high molecular weight polyethylene fiber, comprising the following steps: 1) Mix ultra-high molecular weight polyethylene, polyethylene wax, and solvent to prepare a spinning solution. The ultra-high molecular weight polyethylene has a viscosity-average molecular weight of 1 million to 9 million, and the polyethylene wax has a viscosity-average molecular weight of 1,000 to 5,000. The amount of polyethylene wax used is 0.5 to 20 parts by weight relative to 100 parts by weight of the ultra-high molecular weight polyethylene. 2) The spinning solution is extruded through a spinneret to form a fine spinning stream. 3) While stretching the spun yarn, at least 95 wt% of the solvent is removed from the spun yarn to obtain the ultra-high molecular weight polyethylene fiber, referred to as nascent fiber. After step 3), the nascent fibers are stretched at a temperature of 90-160°C. The operating conditions for step 3) include: temperature 70-180℃, blowing height 0.2-8m, and air volume 60-100m³ / h. 3 / h, The ratio of the stretching speed to the extrusion speed of the spun filament is (12 / 3.5)-10.

2. The manufacturing method according to claim 1, wherein in step 1), the amount of polyethylene wax used is 1-10 parts by weight relative to 100 parts by weight of the ultra-high molecular weight polyethylene, and the amount of solvent used is 1000-1500 parts by weight.

3. The manufacturing method according to claim 1, wherein in step 1), the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 3 million to 5 million, and the viscosity-average molecular weight of the polyethylene wax is 1,500 to 3,000.

4. The manufacturing method according to claim 1, wherein in step 1), the intrinsic viscosity of the polyethylene wax is 0.05-0.3 g / dl, and the intrinsic viscosity of the ultra-high molecular weight polyethylene is 10-45 g / dl.

5. The manufacturing method according to claim 1, wherein in step 2), the extrusion temperature is 130-220°C and the extrusion speed is 2-20 m / min.

6. The manufacturing method according to claim 1, wherein in step 2), the extrusion temperature is 150-180°C and the extrusion speed is 3-10 m / min.

7. The manufacturing method of claim 1, wherein step 3 is performed immediately after the spun yarn leaves the spinneret.

8. The manufacturing method according to claim 1, wherein in step 3), the operating conditions include: Temperature range: 100-140℃, airflow height: 1-8m.

9. The manufacturing method according to claim 1, wherein in step 3), the stretching speed is 5-15 m / min and the stretching ratio is 3-10.

10. The manufacturing method of claim 1, wherein in step 3), the stretching and the solvent removal are performed simultaneously for a period of 3-10 minutes.

11. The manufacturing method of claim 1, wherein after step 3) is completed, the nascent fibers are stretched in 1-8 stages, referred to as post-stretching.

12. The manufacturing method of claim 11, wherein the nascent fibers are stretched in 2-5 stages.

13. The manufacturing method of claim 11, wherein the post-stretching operating conditions include: The stretching temperature is 90-160℃, and the overall stretching ratio is 2-30.

14. The manufacturing method of claim 11, wherein the post-stretching operating conditions include: The stretching temperature is 120-140℃, and the overall stretching ratio is 10-15.

15. An ultra-high molecular weight polyethylene fiber, obtained by the manufacturing method according to any one of claims 1-14, having a core and a self-lubricating layer covering at least a portion of the surface of the core.

16. A fabric comprising the ultra-high molecular weight polyethylene fiber of claim 15.

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