Design And Preparation Of Balloon-Type Tubular Woven Fabric

Among the treatment modalities for cardiovascular disease,balloon catheters cannot be ignored as an interventional method.The balloon catheter is the direct key determinant of the effectiveness of the balloon action and plays a key role in delivering the stent and dilating the vessel.The ideal high-pressure balloon needs to have excellent mechanical properties,controlled inner diameter and wall thickness,and good biocompatibility,and can ensure that the original shape and size can be maintained within the rated pressure range.At present,the international high-pressure balloon preparation process and technology have made certain achievements,but similar products in China are not only limited in size,but also still take the traditional preparation method,and the product structure is single to meet the application needs.Therefore,this subject compounded balloon type and fabric performance,and took a special weaving process to prepare balloon-type tubular woven fabric with thin ends,thick middle,and 3-6 times difference in diameter.In the clinical use of fabric-reinforced balloons,the need for no deformation after inflation must be met.However,how to strictly control the design and production of balloon-type reinforced fabric,so that it has the characteristics of easy processing,controllable inner diameter and tube wall thickness,excellent mechanical properties and not easy to deformation,is one of the research difficulties of balloon-type reinforced fabric.First of all,the morphological design,structural design and process design of the blanks are carried out according to the balloon requirements,and then the feasibility of the design is demonstrated.The morphological design is divided into shape conversion and parameter conversion,and the three-dimensional balloon is converted into a two-dimensional blank by the"flattening-weaving-reduction"principle,and the diameter of the balloon is converted into the folded diameter(width)on the machine.By analyzing the pressure distribution of the tube inflating,combined with the yarn distribution characteristics of the blank,the fabric tissue is selected as plain and the structure is weft-density invariable based on the performance requirements of the balloon in the first position.Based on the consideration of reed material and weft force,the current special trapezoidal reed can only achieve 2-3 times of reed density variation.In order to meet the 3-6 times diameter change range of balloon-type blanks,this paper is designed to add the variable reed entry weaving process to the existing trapezoidal reed for diameter change.In other words,by changing the warp yarn entry number in a set manner during the weaving process and then restarting a fold change in the ordinary variable diameter process,a large fold ratio change of tubular fabrics can be achieved while the trapezoidal reed remains unchanged.Secondly,considering the thickness requirement,medical grade UHMWPE filaments and PET monofilaments were selected as raw materials,special looms and software were commissioned,and four different types of blanks were prepared according to the design parameters.According to the analysis of the raw materials,the warp and weft yarns were found to have a smooth surface and a very low moisture return rate,so targeted measures were taken for yarn weaving and possible yarn slippage during weaving.However,due to the special characteristics of the weaving method of the diameter change tube fabric,the tension of the warp yarn is very unstable due to the lifting and lowering of the chest beam,so the method of controlling the tension by heavy iron is used to avoid the situation of yarn breakage and unclear fell.In addition,it was found that the density was not uniform at the point where the variable and the straight part of the tube met,and this was found to be a defect of the"flattening-weaving"method.Therefore,after theoretical analysis and derivation of the formula for the overall uniformity and deviation of the sample,we compensated the weft density in the original setting to make the preparation process simpler,more controllable and more accurate.Finally,for the requirements of medical balloons,the surface dimensions and mechanical properties of the tube blank samples were tested,mainly including folding diameter,density,thickness and strength tests.It is observed that there is no significant difference between the folding diameter and density of different specimens and the design size,which shows that the principle of equal weft density and reed change process are practical in the process and preparation of large folding ratio reducer fabric,and the optimization measures in the preparation process are effective.In addition,because the main working part of the balloon in the process of use is the middle straight section,so the radial tensile and axial tensile tests were also conducted on the middle straight section of the sample.The tests found that the maximum radial tensile strength of each specification of the middle straight section can reach101N,and the radial elongation at break is 3.43mm,these indicate that the overall strength of the resulting blank is high and not easily deformed.Not only to show the overall tensile strength of the blank fabric,but also to reflect the loading capacity of each part of the fabric,so the top breaking strength of the straight section was also tested,and the minimum value of the top breaking strength of each specification was more than 8N/mm~2,which more truly reflects the loading capacity of the fabric wall and meets the requirements of the fabric reinforced balloon on the wall strength of the blank fabric.In summary,this topic combines the diameter variation tube fabric preparation technology and balloon application demand,through the large fold diameter ratio process design,equal weft density design principle,automatic weaving process technology perfection,realize the large fold diameter ratio tubular woven fabric integrated molding,achieve the purpose of preparing balloon-type tubular woven fabric,provide the experimental basis and method guidance for further development of fabric reinforced high pressure balloon.