Patent Publication Number: US-2020277218-A1

Title: Method for knotting glass fiber bundles and spliced glass fiber bundle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The application is a Continuation-In-Part application of U.S. application Ser. No. 16/080,532, filed Aug. 28, 2018, which is a national phase application of PCT Application No. PCT/CN2017/088993, filed Jun. 19, 2017, which claims priority to Chinese Patent Application No. 2017100714661.1 filed to State Intellectual Property Office on Feb. 9, 2017 and entitled “METHOD FOR KNOTTING GLASS FIBER BUNDLES AND SPLICED GLASS FIBER BUNDLE”, the contents of all of which are incorporated herein by reference in their entireties. 
    
    
     TECHNICAL FIELD OF THE PRESENT INVENTION 
     The present disclosure relates to the technical field of the production of glass fibers, and in particular to a method for knotting glass fiber bundles and a spliced glass fiber bundle. 
     BACKGROUND OF THE PRESENT INVENTION 
     Generally, glass fiber is a material consisting of lots of (usually, hundreds of, thousands of or more) fine glass fibers used together. The diameter of a single fiber is about 10 μm. Since the glass fiber is a brittle material having a high strength but a low folding resistance and a low abrasion resistance, many individual fibers will often be abraded (resulting in fuzzes) during the processing steps, or many fibers are inconsistent in length (causing lugs in assembled fibers), so that the strength or quality of a glass fiber bundle containing a plurality of individual fibers is reduced. Therefore, during the production, such fiber segments often need to be removed, and the remaining qualified fibers need to be knotted and connected, so that two fiber bundles are connected to form a longer fiber bundle for further use. 
     Common methods for knotting glass fiber bundles include: knotting by twining, knotting by glue and knotting by air mixing. The knotting by twining means that two glass fiber bundles are connected by knotting like two ropes or two threads connected. However, the formed knot is large in size, so it is disadvantageous for the further use of fibers. The knotting by glue means that two glass fiber bundles are connected by an adhesive such as glue. In this method, the formed knot is relatively small in size and relatively high in strength. However, since a small amount of other matters such as glue will be introduced into the glass fibers during gluing, the quality of products is influenced adversely. The knotting by air mixing means that individual fibers in two fiber bundles are bent and twined with each other by swelling entanglement of compressed air, so as to connect the two glass fiber bundles. In this method, although there are no other pollutants in the knotted fiber bundle, the formed knot is relatively large in size and modest in strength. The above methods may be used as methods for knotting the whole bundle, and their most obvious disadvantage is that the formed knot is relatively large in size and will influence the subsequent operation and the quality of products. 
     On one hand, when the knot of fiber bundles is large in size, it is difficult to pass the fiber bundles through components such as ceramic eyelets, fiber guide tubes or cutting guns during the subsequent applications of the fiber bundles, and the glass fiber bundles may get stuck or may even break when getting stuck, resulting in the suspension of production. Consequently, both the production efficiency and the product quality are influenced. Even if the glass fiber bundles may not break, more fuzzes will be caused due to the abrasion to the knot, so that the operating environment and the product quality are influenced. On the other hand, a too large knot will slow down the impregnation of glass fiber bundles with resin or cause the glass fiber bundles to be not completely saturated with resin. As a result, white defective blocks are generated in related products, and the appearance and utilization strength of the products are influenced. 
     In addition, during the knotting process by the above knotting methods, particularly when glass fiber bundles are thick, for example, when the linear density of the fiber bundles exceeds 1000tex, the glass fiber bundle as a whole is thicker and harder, and it is difficult to knot two glass fiber bundles together by any one of the above methods. It is difficult to perform the knotting operation. Moreover, it is possible that some fibers in the bundles are not included in the knot, resulting in long escaped fibers (fibers escaped from the whole bundles). During the production and application, the escaped fibers are easily wound on a device, so that the production process and product quality are influenced, and the service life of the device is also influenced. 
     SUMMARY OF THE PRESENT INVENTION 
     In view of the above problems, an objective of the present disclosure is to provide a method for knotting glass fiber bundles and a spliced glass fiber bundle in order to solve any one of the above problems. 
     The present disclosure provides a method for knotting glass fiber bundles, including the following steps of: 
     equally dividing a glass fiber bundle A and a glass fiber bundle B that are to be connected by knotting into n strands, respectively, and marking the strands as A1-An and B1-Bn, respectively, wherein n is a natural number greater than or equal to 2; and 
     successively knotting and splicing the glass fiber strands A1-An and the glass fiber strands B1-Bn in one-to-one correspondence to form n spliced knots. 
     The n spliced knots are staggered in pairs in a lengthwise direction of the glass fiber bundles. 
     A distance L between any two adjacent spliced knots of the n spliced knots in the lengthwise direction of the glass fiber bundles is greater than or equal to a length C of the spliced knots. 
     And, the distance L is between the tail end of the prior spliced knot and the leading end of the later spliced knot. 
     The n spliced knots are formed in any one or more of the following ways: knotting by twining, knotting by glue and knotting by air mixing. 
     The present disclosure further provides a spliced glass fiber bundle, wherein the spliced glass fiber bundle includes a glass fiber bundle A and a glass fiber bundle B that are spliced with each other, and the glass fiber bundle A and the glass fiber bundle B are connected by n spliced knots, where n is a natural number greater than or equal to 2. 
     The n spliced knots are the same in size and staggered in pairs in a lengthwise direction of the spliced glass fiber bundle. 
     A distance L between any two adjacent spliced knots of the n spliced knots in the lengthwise direction of the spliced glass fiber bundle is greater than or equal to a length C of the spliced knots. 
     And, the distance L is between the tail end of the prior spliced knot and the leading end of the later spliced knot. 
     The n spliced knots are formed in any one or more of the following ways: knotting by twining, knotting by glue and knotting by air mixing. 
     The present disclosure has the following beneficial effects: 
     firstly, in the present disclosure, by equally dividing ends of two glass fiber bundles and then splicing the two glass fiber bundles in a staggered knotting manner, the spliced strength of the fiber bundles is ensured, the size and the diameter of the spliced knots are effectively reduced, and it is easier to pass the spliced knots of the glass fiber bundles through a fiber guide device; 
     secondly, since the knots of the glass fiber bundles spliced by the method for knotting glass fiber bundles in the present disclosure are small, the smooth production can be ensured, and it is advantageous for continuous production and quality of subsequent products; and 
     thirdly, the method for knotting glass fibers in the present disclosure is simple, easy to operate and applied to the knotting and splicing of various fiber bundles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings incorporated in the description and constituting a part of the description show the embodiments of the present disclosure, and are used for explaining the principle of the present disclosure in combination with the description. In these drawings, similar reference numerals represent similar elements. The drawings described hereinafter are some of but not all of the embodiments of the present disclosure. A person of ordinary skill in the art can obtain other drawings according to these drawings without paying any creative effort. 
         FIG. 1  is a schematic structure diagram of an embodiment of glass fiber bundles connected by a method for knotting glass fiber bundles according to the present disclosure; 
         FIG. 2  is a schematic structure diagram of glass fiber bundles connected by conventional knotting by twining; 
         FIG. 3  is a schematic structure diagram of glass fiber bundles connected by conventional knotting by glue; 
         FIG. 4  is a schematic structure diagram of an embodiment of a glass fiber bundle according to the present disclosure; and 
         FIG. 5  is a schematic structure diagram of another embodiment of the glass fiber bundle according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     To make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be described below clearly and completely with reference to the accompanying drawings in the embodiments of the present disclosure. Apparently, the described embodiments are just some but not all of the embodiments of the present disclosure. All other embodiments obtained by a person of ordinary skill in the art without paying any creative effort on the basis of the embodiments in the present disclosure shall fall into the protection scope of the present disclosure. It is to be noted that the embodiments in the present application and the features in the embodiments can be combined at will if not conflict. 
     In the present disclosure, by equally dividing ends of two glass fiber bundles into a plurality of sub-bundles, then knotting and connecting the sub-bundles, by staggering the spliced knots of the fiber bundles in pairs, in this way the diameter of the spliced knots is reduced, and the fiber bundles will not be stuck, broken or excessively abraded to cause fuzzes when passing through a fiber guide device, for example, a ceramic eyelet, at a high speed. Moreover, during chopping, the quality problem caused when the spliced knots are not chopped due to their too large sizes and too high hardness can be avoided, and the probability of defects due to imperfect impregnation of too large spliced knots in glass fiber reinforced products can also be reduced. 
     Firstly, the present disclosure provides a method for knotting glass fiber bundles, including the following steps of: 
     equally dividing a glass fiber bundle A and a glass fiber bundle B that are to be connected by knotting into n strands, respectively, and marking the strands as A1-An and B1-Bn, respectively, where n is a natural number greater than or equal to 2; and successively knotting and splicing the glass fiber strands A1-An and the glass fiber strands B1-Bn in one-to-one correspondence to form n spliced knots. 
       FIG. 1  shows a schematic structure diagram of glass fiber bundles connected by the method for knotting glass fiber bundles according to the present disclosure. As shown in  FIG. 1 , n spliced knots are staggered in pairs along a lengthwise direction of the glass fiber bundles, and any two spliced knots are prevented from paralleling or overlapping with each other, so that the purpose of reducing the width or diameter of the spliced knots is realized. Further, in order to avoid the overlapping of any two spliced knots, in the lengthwise direction of the glass fiber bundles, a certain distance L can be kept between adjacent spliced knots. For example, the distance between two adjacent spliced knots can be set to 3 cm, 5 cm, 10 cm, etc. The specific value can be selectively set depending on the diameter of the glass fiber bundles, the size of the spliced knots and other factors. In a typical embodiment, the distance L between any two adjacent spliced knots of the n spliced knots in the lengthwise direction of the glass fiber bundles is greater than or equal to the length C of the spliced knots. 
     And the distance L is between the tail end of the prior spliced knot and the leading end of the later spliced knot (that is, net distance of any two adjacent spliced knots). 
     Specifically, the n spliced knots can be formed in any one or more of the following ways: knotting by twining, knotting by glue and knotting by air mixing. The specific way of forming the spliced knots has been known in the prior art and will be not described in detail here. 
     Compared with the conventional knotting or glue splicing of the whole glass fiber bundle, if two glass fiber bundles are spliced by the method for knotting glass fiber bundles in the present disclosure, the sectional area of the spliced knots is reduced significantly.  FIG. 2  shows a schematic structure diagram of glass fiber bundles spliced by conventional knotting by twining, and  FIG. 3  shows a schematic structure diagram of glass fiber bundles connected by conventional splicing by glue. If the sectional area of the whole glass fiber bundle (i.e., the sum of sectional areas of all individual fibers in the whole glass fiber bundle) is S, by the knotting method shown in  FIG. 2 , the sectional area of the knots is 4S; by the splicing method by glue shown in  FIG. 3 , due to the use of an adhesive, the sectional area of the knot is greater than 2S; and, if the glass fiber bundles are spliced by the knotting method of the present disclosure, the sectional area of each equally divided fiber bundle is S/n, and the sectional area of the knots is (4S/n)+(n−1)*S/n=3S/n+S. 
     If the glass fiber bundles are equally divided into 2 strands, as shown in  FIG. 1 , the glass fiber bundle A is divided into sub-bundles A1 and A2, and the glass fiber bundle B is divided into sub-bundles B1 and B2, the total sectional area after splicing is 3S/2+S=2.5S. After the whole glass fiber bundle is divided into two strands which are then spliced, the sectional area is (4S−2.5S)/(4S)=37.5% less than the sectional area formed by the conventional bundle knotting and splicing. If the glass fiber bundle is equally divided into 3 strands, the total sectional area after splicing is 3S/3+S=2S, and the sectional area is (4S−2S)/(4S)=50% less than the sectional area formed by the conventional bundle knotting and splicing. If the glass fiber bundle is equally divided into 4 strands, the total sectional area after splicing is 3S/4+S=1.75S, and the sectional area is (4S−1.75S)/(4S)=56.25% less than the sectional area formed by the conventional bundle knotting and splicing. 
     In the present disclosure, the sectional area of each equally divided fiber bundle is S/n, and the sectional area of the knots is (4S/n)+(n−1)*S/n=3S/n+S, and the spliced knots have a certain height. 
     When the distance L between any two adjacent spliced knots of the n spliced knots in the lengthwise direction of the glass fiber bundles (that is, the net distance of any two adjacent spliced knots) is greater than or equal to the length C of the spliced knots, there are enough space between two adjacent spliced knots to accommodate two glass fiber bundle divided, and two adjacent spliced knots can be staggered in a lengthwise direction of the spliced glass fiber bundle, so that two adjacent spliced knots smoothly through the porcelain eyes, and the sectional area of the knots is (4*0.5S)+(0.5S)=2.5S. If the distance L between any two adjacent spliced knots is less than the length C of the spliced knots, there are not enough space to accommodate two glass fiber bundle divided, and two adjacent spliced knots will be closely arranged in a lengthwise direction of the spliced glass fiber bundle, two spliced knots will be overlapped with each other and the sectional area of half a knot will be added, and the sectional area of the knots is (4*0.5S)+(0.5*(4*0.5S))=3S. 
     In conclusion, when two glass fiber bundles are spliced by the method for knotting glass fiber bundles in the present disclosure, the spliced knots of each strand are staggered with each other, so that the total sectional area of the formed knots is obviously less than the sectional area of the knots formed by the conventional splicing method. Accordingly, it is smoother to use the spliced glass fiber bundle and easier to cut the spliced glass fiber bundle off during using, and the quality of the produced products is also improved greatly. 
     Corresponding to the method for knotting glass fiber bundles, the present disclosure further provides a spliced glass fiber bundle.  FIG. 4  shows a schematic structure diagram of an embodiment of the spliced glass fiber bundle, and  FIG. 5  shows a schematic structure diagram of another embodiment of the spliced glass fiber bundle. With reference to  FIGS. 4 and 5 , the spliced glass fiber bundle includes a glass fiber bundle A and a glass fiber bundle B that are spliced with each other. Ends of the glass fiber bundle A and the glass fiber bundle B are equally divided into n strands, and the glass fiber bundle A and the glass fiber bundle B are connected by n spliced knots, where n is a natural number greater than or equal to 2. 
     Specifically, the n spliced knots are the same in size and staggered in pairs in a lengthwise direction of the spliced glass fiber bundle. That is, any two spliced knots will not be overlapped with each other, so that the sectional area or diameter of the spliced glass fiber bundle at the spliced knots is minimized. Exemplarily, as shown in  FIGS. 4 and 5 , the glass fiber bundle A is divided into sub-bundles A1, A2 and A3, and the glass fiber bundle B is divided into sub-bundles B1, B2 and B3. In an embodiment shown in  FIG. 4 , three spliced knots are successively arranged at intervals; however, in an embodiment shown in  FIG. 5 , three spliced knots are arranged in random order, and there is still a certain distance L between two adjacent spliced knots in the lengthwise direction of the glass fiber bundle. However, in order to reduce the length of the spliced knots of the glass fiber bundle A and the glass fiber bundle B as far as possible, the distance L should not be too large, as long as it is ensured that any two sliced knots will not be overlapped with each other. 
     In a typical embodiment, the distance L between any two adjacent spliced knots of the n spliced knots in the lengthwise direction of the spliced glass fiber bundle is greater than or equal to the length C of each spliced knot. 
     It is to be noted that the n spliced knots are formed in any one or more of the following ways: knotting by twining, knotting by glue and knotting by air mixing. 
     The drawings of the present disclosure only show the plane distribution of the spliced knots of the glass fiber bundle, as shown in  FIGS. 1, 4 and 5 . However, in practical application, the whole glass fiber bundle is cylindrical (three-dimensional); and the equally divided glass fiber bundles are cylindrical distributed, rather than planar distributed. Therefore, any one of spliced knots is adjacent to multiple spliced knots. All spliced knots of the present disclosure are staggered in pairs in a lengthwise direction of the spliced glass fiber bundle, and any two spliced knots will not be overlapped with each other. 
     The contents described above can be implemented separately or jointly in various ways, and these transformations shall fall into the protection scope of the present disclosure. 
     The specific dimension values of the components listed herein are exemplary numerical values, and the dimension parameters of different components can have different numerical values as required in practical operations. 
     It is to be noted that, as used herein, the term “comprise/comprising”, “contain/containing” or any other variants thereof is non-exclusive, so that an object or a device containing a series of elements contains not only these elements, but also other elements not listed clearly, or further contains inherent elements of the object or device. Unless otherwise defined herein, an element defined by the statement “comprises/comprising an/a . . . ” does not exclude other identical elements in the object or device including this element. 
     The foregoing embodiments are merely used for describing the technical solutions of the present disclosure, and the present disclosure has been described in detail just by preferred embodiments. It should be understood by a person of ordinary skill in the art that modifications or equivalent replacements can be made to the technical features of the present disclosure without departing from the spirit and scope of the technical solutions of the present disclosure, and these modifications or equivalent replacements shall fall into the scope defined by the appended claims of the present disclosure. 
     INDUSTRIAL APPLICABILITY 
     In the present disclosure, by equally dividing ends of two glass fiber bundles into a plurality of sub-bundles, then knotting and connecting the sub-bundles, by staggering the spliced knots of the fiber bundles in pairs, in this way the diameter of the spliced knots is reduced, and the fiber bundles will not be stuck, broken or excessively abraded to cause fuzzes when passing through a fiber guide device, for example, a ceramic eyelet, at a high speed. Moreover, during chopping, the quality problem caused when the spliced knots are not chopped due to their too large size and too high hardness can be avoided, and the probability of defects due to imperfect impregnation of too large spliced knots in glass fiber reinforced products can also be reduced.