A super high molecular weight polyethylene chain and its preparation method

Abstract

The chain of ultra-high molecular weight polyethylene disclosed in the present invention comprises a plurality of interconnected links, each link comprising 1-10 layers of loop strips, and the ends of the loop strips are stitched and fixed to the formed link body by silk threads parallel to the long side direction of the loop strips. The preparation method of the chain of ultra-high molecular weight polyethylene of the present invention comprises: Step 1: Laminating and winding a strip of ultra-high molecular weight polyethylene in parallel to form a link with 1-10 layers of loop strips, and stitching and fixing the end of the strip to the formed link body by silk threads parallel to the long side direction of the loop strips to make the first link; Step 2: Passing another strip of ultra-high molecular weight polyethylene hollowly through the first link prepared in Step 1, and making the second link by referring to the method of Step 1; Step 3: Repeating the method of Step 2 to prepare a chain comprising a plurality of interconnected links. The chain of ultra-high molecular weight polyethylene prepared by the present invention has higher breaking strength and longer service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthetic fiber chains, and particularly relates to a chain containing ultra-high molecular weight polyethylene and a preparation method thereof. Background Art

[0002] Ultra-high molecular weight polyethylene (UHMWPE) is the fiber with the highest specific strength and specific modulus in the world. Its specific strength is more than ten times that of steel wires with the same cross-section. It has the advantages of stable dimensions, low shrinkage rate, chemical corrosion resistance, good mechanical properties, and light weight.

[0003] The core structures of existing UHMWPE mooring cables have two types: single-core twisted ropes and multi-core parallel ropes. However, for the single-core twisted ropes, due to the unstable core structure, torsion is likely to occur when the mooring cable is under tension. For the multi-core parallel ropes, the core structure is extremely loose. Once the outer protective layer is damaged, the loss of the strength of the entire mooring cable is the sum of the strength losses of each core rope, which will directly endanger the safety of the mooring of the offshore platform. Moreover, the deviation of the lengths of the parallel core ropes during the manufacturing and coiling of this type of mooring cable is relatively large, resulting in a decrease in the strength of the mooring cable by more than 10%.

[0004] Patent CN101641532B discloses a chain comprising a plurality of interconnected links, at least some of the links containing ultra-high molecular weight polyethylene (UHMWPE) fibers. The layers of the link are held together by S-shaped stitching of silk threads. The UHMWPE chain disclosed in this invention can avoid the problems that the single-core twisted rope is prone to torsion and the multi-core parallel rope has an extremely loose core structure, which is extremely easy to directly endanger the safety of the mooring of the offshore platform if broken, and the large deviation of the lengths of the parallel core ropes during the manufacturing and coiling of these two types of mooring cables, resulting in a decrease in the strength of the mooring cable. However, the S-shaped stitching method in this invention will increase the lateral tension of the link, thus greatly reducing the breaking strength of the link. In the prior art, the two ends of the strip for preparing the link are usually stitched and fixed to the prepared link body by silk threads perpendicular to the long side direction of the strip, which also increases the lateral tension of the link, thereby reducing the breaking strength of the link. Therefore, there is an urgent need for an UHMWPE chain that can minimize the influence of the processing method on the breaking strength of the UHMWPE chain. Summary of the Invention

[0005] The object of the present invention is to overcome the defect that the breaking strength of ultra-high molecular weight polyethylene chains decreases during the preparation process in the prior art, and to provide an ultra-high molecular weight polyethylene chain that can maintain its breaking strength to the maximum extent, thereby improving the breaking strength and service life of the entire ultra-high molecular weight polyethylene chain, being more environmentally friendly, and reducing the manufacturing, transportation and storage costs.

[0006] To achieve the above object of the invention, the present invention provides an ultra-high molecular weight polyethylene chain, the chain comprising a plurality of interconnected link rings, the link rings comprising 1-10 layers of ultra-high molecular weight polyethylene loop strip bands, and the ends of the loop strip bands being stitched and fixed to the formed link ring body by threads parallel to the long side direction of the loop strip bands.

[0007] The chain structure composed of a plurality of interconnected link rings is stable and not easily twisted under tension, avoiding the decrease in breaking strength caused by the deviation of the lengths of the individual strands during the manufacture and coiling of traditional ropes and cables; the width, length and the number of stacked layers of the loop strip bands can be adjusted to meet the requirements of different breaking strengths. Since the chain is formed by interlocking the rings, the length of the chain is not limited. The ends of the loop strip bands are stitched and fixed to the formed link ring body by threads parallel to the long side direction of the loop strip bands, avoiding the lateral pulling force brought by the stitching method using threads perpendicular to the long side direction of the strip in the prior art, and maintaining the breaking strength of the ultra-high molecular weight polyethylene chain to a greater extent.

[0008] As a preferred technical solution, at least some of the loop strip bands of each layer of the above link rings are stitched together by threads parallel to the long side direction of the loop strip bands.

[0009] As a preferred technical solution, the above threads are ultra-high molecular weight polyethylene threads.

[0010] The loop strip bands of each layer are stitched together by threads parallel to the long side direction of the loop strip bands, avoiding the lateral pulling force brought by the traditional stitching method, and maintaining the breaking strength of the ultra-high molecular weight polyethylene chain to a greater extent.

[0011] As a preferred technical solution, the above link rings are formed by parallelly laminating and winding an ultra-high molecular weight polyethylene strip into a link ring with 1-10 layers of ultra-high molecular weight polyethylene loop strip bands, and the ends of the loop strip bands can overlap a certain length in the long side direction, or end to end, or be separated by a certain length.

[0012] As a preferred technical solution, the structures of the individual link rings of the above chain are the same to ensure the same breaking strength between the individual link rings and to bring the breaking strength of the ultra-high molecular weight polyethylene chain to the best state.

[0013] The present invention also provides a method for preparing the above-mentioned ultra-high molecular weight polyethylene chain, comprising the following steps:

[0014] Step 1: Stack and wind a strip of ultra-high molecular weight polyethylene in parallel layers to form a link with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips. Fix the end of the strip to the formed link body by sewing with a silk thread parallel to the long side of the loop strip to make the first link.

[0015] Step 2: Pass another strip of ultra-high molecular weight polyethylene through the hollow of the first link prepared in Step 1, stack and wind it in parallel layers to form a link with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips. Fix the end of the strip to the formed link body by sewing with a silk thread parallel to the long side of the loop strip to make the second link.

[0016] Step 3: Repeat the method of Step 2 to prepare a chain comprising multiple interconnected links.

[0017] As a preferred technical solution, first prepare multiple first links through the above Step 1, and then connect the multiple first links in pairs to form a chain. The specific way of connecting the first links in pairs is: Pass a strip of ultra-high molecular weight polyethylene through the hollows of two first links, stack and wind it in parallel layers to form a link with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips. Fix the end of the strip to the formed link body by sewing with a silk thread parallel to the long side of the loop strip.

[0018] The advantage of preparing a link with an ultra-high molecular weight polyethylene strip is that it can meet the requirements of different breaking strengths by adjusting the main machine traction, width, length of the strip during preparation, and the number of stacked layers of the loop strip. Since it forms a chain by interlocking rings, the length of the chain is not limited.

[0019] As a preferred technical solution, in the above method for preparing an ultra-high molecular weight polyethylene chain, at least some of the links have steps of keeping the loop strips at each layer together by sewing with a silk thread parallel to the long side of the loop strip.

[0020] As a preferred technical solution, the above silk thread is an ultra-high molecular weight polyethylene silk thread.

[0021] The end of the loop strip is fixed to the formed link body by sewing with a silk thread parallel to the long side of the loop strip, and the loop strips at each layer are kept together by sewing with a silk thread parallel to the long side of the loop strip, avoiding the lateral tension brought by the traditional silk thread sewing method and maintaining the breaking strength of the ultra-high molecular weight polyethylene chain to a greater extent.

[0022] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0023] 1. The chain of ultra-high molecular weight polyethylene of the present invention is composed of multiple interconnected chain links, and the chain structure is stable. It is not easy to twist under tension, avoiding the reduction of breaking strength caused by the deviation of the length of each strand during the manufacture and coiling of traditional ropes and cables. Since it forms a chain by interlocking rings, the length of the chain is not limited. It has better flexibility than traditional ultra-high molecular weight polyethylene ropes.

[0024] 2. When the ultra-high molecular weight polyethylene chain of the present invention has the same width, length, and number of layers of overlapping ring strips as the ultra-high molecular weight polyethylene chain in the prior art, it has higher breaking strength and longer service life. When preparing ultra-high molecular weight polyethylene chains with the same breaking strength and service life, the ultra-high molecular weight polyethylene material required by the present invention is significantly less than that required by the prior art, saving resources, being more environmentally friendly, and the prepared ultra-high molecular weight polyethylene chain is lighter in weight and smaller in volume, reducing the manufacturing, transportation, and storage costs.

[0025] 3. In the present invention, the main machine traction force, the width of the strip, and the number of layers of overlapping of the ring during the preparation of the ultra-high molecular weight polyethylene strip can be adjusted to meet the requirements of different breaking strengths. Description of the Drawings

[0026] Figure 1 This is the first embodiment of the ultra-high molecular weight polyethylene chain of the present invention.

[0027] Figure 2 This is the second embodiment of the ultra-high molecular weight polyethylene chain of the present invention.

[0028] Figure 3 This is the third embodiment of the ultra-high molecular weight polyethylene chain of the present invention.

[0029] Figure 4 This is the ultra-high molecular weight polyethylene chain prepared by the method disclosed in CN101641532B.

[0030] Explanation of the reference numerals in the drawings: 1 - link a, 2 - link b, 3 - link c. Detailed Embodiment

[0031] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Rather, the present invention covers any alternatives, modifications, equivalent methods, and schemes made to the essence and scope of the invention as defined by the claims. Further, in order to enable the public to better understand the present invention, in the following detailed description of the present invention, some specific details are described in detail. Those skilled in the art can fully understand the present invention without the description of these details.

[0033] In the invention, a strip refers to a flexible and slender body whose thickness is much smaller than its width, and such a strip can be easily made by weaving multifilament yarns into any structure known in the art, such as plain and / or twill weaving structures.

[0034] As Figure 1 and Figure 2 The link a1 shown contains 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and the ends of the loop strips are stitched and fixed to the formed link a1 body by silk threads parallel to the long side direction of the loop strips; Figure 1 and Figure 2 The two ends of the loop strip shown overlap a length in the long side direction, and according to specific circumstances, they can also be end-to-end or separated by a length; Figure 1 and Figure 2 The link a1 shown is composed of four layers of loop strips, but it can have more or fewer layers, depending on the required load-bearing capacity; Figure 1 and Figure 2 The diameters of the individual links a1 shown are the same, and according to specific circumstances, the diameters of the links a1 can also be different.

[0035] As Figure 2 and Figure 3 The link b2 shown contains 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and the loop strips of each layer of the link b2 are held together by stitching with silk threads parallel to the long side direction of the loop strips; Figure 2 and Figure 3 The two ends of the loop strip shown overlap a length in the long side direction, and according to specific circumstances, they can also be end-to-end or separated by a length; Figure 2 and Figure 3 The link b2 shown is composed of four layers of loop strips, but it can have more or fewer layers, depending on the required load-bearing capacity. Figure 2 and Figure 3 The diameters of the individual links b2 shown are the same, and according to specific circumstances, the diameters of the links b2 can also be different.

[0036] As Figure 1The shown ultra-high molecular weight polyethylene chain A includes a plurality of interconnected links a1. It is prepared through the following steps: Step 1: Wind an ultra-high molecular weight polyethylene strip in parallel layers to form a link a1 with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips. Fix the end of the strip to the formed link a1 body by sewing with a silk thread parallel to the long side direction of the loop strip to make the first link; Step 2: Pass another ultra-high molecular weight polyethylene strip through the hollow of the first link prepared in Step 1, wind it in parallel layers to form a link a1 with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and fix the end of the strip to the formed link a1 body by sewing with a silk thread parallel to the long side direction of the loop strip to make the second link; Step 3: Repeat the method of Step 2 to prepare a chain including a plurality of interconnected links a1.

[0037] As Figure 2 The shown ultra-high molecular weight polyethylene chain B includes link a1 and link b2 in any quantity ratio. It is prepared through the following steps: Step 1: Wind an ultra-high molecular weight polyethylene strip in parallel layers to form a link a1 with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips. Fix the end of the strip to the formed link a1 body by sewing with a silk thread parallel to the long side direction of the loop strip to make the first link; Step 2: Pass another ultra-high molecular weight polyethylene strip through the hollow of the first link prepared in Step 1, wind it in parallel layers to form a link b2 with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and keep the layers of the loop strips of link b2 together by sewing with a silk thread parallel to the long side direction of the loop strip to make the second link; Step 3: Repeat the method of Step 2 or Step 3 to prepare a chain including a plurality of interconnected links a1 and link b2; where the order of Step 1 and Step 2 can be swapped at will, and the number of times Step 1 and Step 2 are implemented can also be combined at will.

[0038] As Figure 3 The shown ultra-high molecular weight polyethylene chain C includes a plurality of interconnected links b2. It is prepared through the following steps: Step 1: Wind an ultra-high molecular weight polyethylene strip in parallel layers to form a link b2 with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and keep the layers of the loop strips of link b2 together by sewing with a silk thread parallel to the long side direction of the loop strip to make the first link; Step 2: Pass another ultra-high molecular weight polyethylene strip through the hollow of the first link prepared in Step 1, wind it in parallel layers to form a link b2 with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and keep the layers of the loop strips of link b2 together by sewing with a silk thread parallel to the long side direction of the loop strip to make the second link; Step 3: Repeat the method of Step 2 to prepare a chain including a plurality of interconnected links b2.

[0039] The above-mentioned Chain A, Chain B, and Chain C can first prepare a plurality of first chain links through the above-mentioned Step 1, and then form a chain by connecting the plurality of first chain links in pairs. The specific method of connecting the first chain links in pairs is as follows: Pass a strip of ultra-high molecular weight polyethylene through the hollows of two first chain links, and stack them in parallel to form a chain link of 1-10 layers of ultra-high molecular weight polyethylene loop strip. Fix the end of the strip to the formed chain link body by sewing with a silk thread parallel to the long side direction of the loop strip, or keep each layer of loop strip together by sewing with a silk thread parallel to the long side direction of the loop strip.

[0040] The number of the above-mentioned sewing silk threads parallel to the long side direction of the loop strip can be selected according to specific circumstances.

[0041] As Figure 4 shown in the ultra-high molecular weight polyethylene Chain D, it includes a plurality of interconnected chain links c3. The chain link c3 includes 1-10 layers of ultra-high molecular weight polyethylene loop strips, and each layer of loop strip in the chain link c3 is kept together by sewing with a silk thread in an S-shaped path.

[0042] Figures 1 - 4 shows a chain link composed of four layers of loop strips, but it can have more or fewer layers, depending on the specific load and application conditions.

[0043] Now, the present invention will be further described through the following examples and comparative examples, so as to compare the present invention with the prior art according to Chinese Patent CN101641532B.

[0044] Ultra-high molecular weight polyethylene chains A 1 、B 1 、C 1 and D 1 are prepared by the above method. Ultra-high molecular weight polyethylene chains A 1 、B 1 、C 1 and D 1 are specific embodiments of ultra-high molecular weight polyethylene chains A, B, C, and D respectively. For ultra-high molecular weight polyethylene chains A 1 、B 1 、C 1 and D 1 , the ends of each loop strip overlap a certain length in the long side direction; each chain link is composed of four layers of loop strips, and the diameters of each chain link are the same; ultra-high molecular weight polyethylene chains A 1 、B 1 、C 1 、D 1 are composed of 4 chain links; among them, ultra-high molecular weight polyethylene chain B 1 is interconnected at intervals by chain link a1 and chain link b2.

[0045] The lengths and widths of the above-prepared ultra-high molecular weight polyethylene chains A1, B1, C1, and D1 are the same.

[0046] The first series of tests included chain A 1 , B 1 , C 1 , D 1 in a tensile test.

[0047] The second series of tests included wear tests on ultra-high molecular weight polyethylene chains A 1 , B 1 , C 1 , and D 1 under dry and wet conditions.

[0048] Tensile tests were performed on ultra-high molecular weight polyethylene chains A 1 , B 1 , C 1 , D 1 using a Zwick 1484 universal testing machine at a temperature of approximately 21°C and a speed of 100 mm / min.

[0049] Wear tests were performed on a Static Abrasion Test, a spoke wear tester used in the rope and cable industries. The above ultra-high molecular weight polyethylene chains A 1 , B 1 , C 1 , and D 1 were brought into contact with a rotating body (a spoke, 0.15 m in diameter) that included 20 rods, each 15 mm in diameter and parallel to the axis of rotation of the rotating body. The test could be performed dry or wet, and in the latter case, water was continuously added to each part of the ultra-high molecular weight polyethylene chains A 1 , B 1 , C 1 , and D 1 in contact with the spoke. The speed of the wheel was 2 revolutions per second, and the load on the ultra-high molecular weight polyethylene chains A 1 , B 1 , C 1 , and D 1 was 6% of the breaking strength. The number of cycles until failure was recorded.

[0050] Example 1:

[0051] Determine ultra-high molecular weight polyethylene chains A made of SK75 yarn from DSM Dyneema B.V., the Netherlands 1 , B 1 , C 1 , D1 Breaking load and breaking strength. Each chain has 4 links made of 16 strands of 1760 dtex SK75 yarn, and the tensile test is carried out as above. The results are summarized in Table 1.

[0052] Table 1: Tensile test results of ultra-high molecular weight polyethylene chains A 1 , B 1 , C 1 , D 1

[0053] Sample Weight (dtex) Breaking load (N) Breaking strength (cN / dtex) Strain (%) <![CDATA[UHMWPE Chain A 1 > 56400 3282 5.82 3.3 <![CDATA[UHMWPE Chain B 1 > 56500 3220 5.71 3.4 <![CDATA[UHMWPE Chain C 1 > 56600 3096 5.49 3.3 <![CDATA[UHMWPE Chain D 1 > 56300 2714 4.82 3.2

[0054] From the above tensile test results, the following conclusions can be drawn: On the basis of the same weight, the ultra-high molecular weight polyethylene chains A 1 , B 1 , C 1 of the present invention have higher breaking strength than the ultra-high molecular weight polyethylene chain D 1 prepared according to the prior art CN101641532B.

[0055] Example 2:

[0056] Test the number of cycles to failure of ultra-high molecular weight polyethylene dry chains A made of SK75 yarn from DSM Dyneema B.V. 1 , B 1 , C 1 , and D 1 until failure. Test three chains. Each chain has 4 links made of 16 strands of 1760 dtex SK75 yarn, and the wear test is carried out as above. The results are summarized in Table 2.

[0057] Table 2: Wear test results of ultra-high molecular weight polyethylene dry chains A 1 , B 1 , C 1 , and D 1

[0058] Sample #1 #2 #3 Average value <![CDATA[UHMWPE Dry Chain A 1 > 846 831 817 831 <![CDATA[UHMWPE Dry Chain B 1 > 852 871 862 861 <![CDATA[UHMWPE dry chain C 1 > 841 826 830 832 <![CDATA[UHMWPE Dry Chain D 1 > 572 591 601 588

[0059] From the above wear test results, the following conclusions can be drawn: The ultra-high molecular weight polyethylene dry chains A 1 , B 1 and C 1 prepared according to the present invention have significantly improved service life under dynamic load conditions compared with the ultra-high molecular weight polyethylene dry chain D 1 prepared according to the prior art CN101641532B.

[0060] Example 3:

[0061] The test was carried out by DSM Dyneema B.V. Ultra-high molecular weight polyethylene wet chains A 1 、B 1 、C 1 、and D 1 made of SK75 yarn until the number of cycles to failure. Three chains were tested. Each of the chains had 4 links made of 16 pieces of 1760 dtex SK75 yarn, and the wear test was carried out as above. The results are summarized in Table 3.

[0062] Table 3: Wear test results of ultra-high molecular weight polyethylene wet chains A 1 、B 1 、C 1 、and D 1

[0063] Sample #1 #2 #3 Average value <![CDATA[UHMWPE wet chain A 1 > 2762 2683 2882 2775 <![CDATA[UHMWPE wet chain B 1 > 2676 2732 2716 2708 <![CDATA[UHMWPE wet chain C 1 > 2831 2762 2759 2784 <![CDATA[UHMWPE wet chain D 1 > 1983 2004 1996 1994

[0064] From the above wear test results, the following conclusions can be drawn: The ultra-high molecular weight polyethylene wet chains A 1 、B 1 and C 1 prepared according to the present invention have significantly improved service life under dynamic load conditions compared to the ultra-high molecular weight polyethylene wet chain D 1 prepared according to the prior art CN101641532B.

[0065] The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. For those of ordinary skill in the art, several variations and improvements can be made without departing from the present invention, and these should also be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing a ultra-high molecular weight polyethylene chain. The ultra-high molecular weight polyethylene chain comprises a plurality of interconnected links. Each link comprises 1 - 10 layers of ultra-high molecular weight polyethylene loop strips. The ends of the loop strips are stitched and fixed to the formed link body by threads parallel to the long side direction of the loop strips. Between the layers of loop strips of at least some of the links, they are held together by threads stitched parallel to the long side direction of the loop strips. The threads are ultra-high molecular weight polyethylene threads. The link is formed by parallelly laminating and winding an ultra-high molecular weight polyethylene strip into a link with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips. The two ends of the strip can overlap a length in the long side direction, or be end-to-end, or be separated by a length. The structures of the individual links of the chain are the same. Characterized in that, it includes the following steps: Step 1: Parallelly laminate and wind an ultra-high molecular weight polyethylene strip into a link with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and stitch and fix the ends of the strip to the formed link body by threads parallel to the long side direction of the loop strips to make the first link. Step 2: Pass another ultra-high molecular weight polyethylene strip hollowly through the first link prepared in Step 1, parallelly laminate and wind it into a link with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and stitch and fix the ends of the strip to the formed link body by threads parallel to the long side direction of the loop strips to make the second link. Step 3: Repeat the method of Step 2 to prepare a chain comprising a plurality of interconnected links. It also includes the step of holding together the layers of loop strips of at least some of the links by stitching with threads parallel to the long side direction of the loop strips; the threads are ultra-high molecular weight polyethylene threads.

2. A method for preparing a ultra-high molecular weight polyethylene chain as claimed in claim 1, Characterized in that, first prepare a plurality of first links through the said Step 1, and then connect the plurality of first links in pairs to form a chain. The specific way of connecting the first links in pairs is: Pass an ultra-high molecular weight polyethylene strip hollowly through two first links, parallelly laminate and wind it into a link with 1 - 10 layers of ultra-high molecular weight polyethylene loop strips, and stitch and fix the ends of the strip to the formed link body by threads parallel to the long side direction of the loop strips.

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