Fluorine-containing fiber substrate and gasket made of the fluorine-containing fiber substrate, and use

Abstract

A fluorine-containing fiber substrate and a gasket made of the fluorine-containing fiber substrate, and a use of the gasket. The substrate comprises a woven fabric, and an upper thread and a bobbin thread fixed on the woven fabric, the upper thread being a twisted yarn formed by a fluorine-containing fiber and a fiber having a tensile strength of 6.6 cN / dtex or more and a modulus of 80 cN / dtex or more, and the woven fabric being formed of an inorganic fiber. The fluorine-containing fiber substrate of the present invention has the characteristics of low friction coefficient, good dimensional stability, and excellent abrasion durability. The gasket made of the fluorine-containing fiber substrate has the characteristics of pressure resistance and shear resistance, and can be applied to the fields of motor vehicle drive bearings and engineering machinery bearings.

Description

Fluorofiber-containing substrate, gasket made therefrom, and use thereof TECHNICAL FIELD

[0001] The present invention relates to a fluorofiber-containing substrate, a gasket made therefrom, and use thereof. BACKGROUND

[0002] The drive shaft is an important part of the automobile transmission system, which transmits power to the hub bearing to provide driving force for the vehicle. There is a complete annular fitting surface between the hub bearing and the drive shaft, and when the vehicle is moving, stick-slip motion will occur on the fitting surface. However, as the power of the vehicle increases, the problem of abnormal noise caused by stick-slip motion becomes more and more serious. In order to solve this problem of abnormal noise, a friction-reducing agent is sprayed on the fixed end surface of the drive shaft to form a friction-reducing coating, but this coating is prone to fall off. In order to solve the problem of coating falling off, a metal-based friction-reducing gasket is installed on the fixed end surface of the drive shaft, but this gasket has the risk of breaking and is easy to fly out during high-speed driving.

[0003] In view of the above problems, the skilled person has developed a composite material containing self-lubricating fibers. For example, Japanese Patent Publication No. 2005-220487 discloses a fluorine fiber fabric and a composite material thereof. After the fabric is impregnated with resin and cured, a hard composite material is formed. Fluorine fibers are used as lubricants in the field of friction-reducing gaskets. Since the processing method is simply weaving or knitting, the distribution of fibers is in the plane of the fabric, and the arrangement of fibers in the thickness direction is less. Therefore, when the composite material is subjected to shearing or bending, it is easy to break due to the lack of pressure-bearing fibers.

[0004] For another example, Chinese Patent Publication No. CN114016224A discloses a self-lubricating material, which includes a substrate formed of organic fibers and fiber bundles embroidered on the substrate. Since the substrate is composed of organic fibers, the tensile deformation of the organic fibers is large, and the angle between the embroidery thread and the substrate is 10° to 80°. This angle configuration will pull the fibers in the warp and weft directions of the substrate, resulting in a decrease in the dimensional stability of the self-lubricating material.

[0005] For another example, International Patent Publication No. WO2019 / 163046 discloses a method for manufacturing a composite material product. The composite material is formed by a specific fiber cloth, an inner liner sheet, and an embroidery fabric formed by embroidering the fiber cloth with embroidery thread, and then impregnating and curing the embroidery fabric with resin. Since the embroidery thread does not use fluorine-containing materials, the friction coefficient of the embroidery surface is high, and the wear of the gasket is large during driving of the vehicle. SUMMARY

[0006] The present invention aims to provide a fluorofiber-containing substrate with low friction coefficient, good dimensional stability, and excellent wear durability.

[0007] Another object of the present application is to provide a gasket made of the fluorine-containing fiber base material, which is resistant to pressure and shearing.

[0008] The technical solution of the present application is as follows: the fluorine-containing fiber base material of the present application comprises a woven fabric and face threads and bottom threads fixed on the woven fabric, the face threads are combined twisted yarns formed by fluorine-containing fibers and fibers with tensile strength of 6.6 cN / dtex or more and modulus of 80 cN / dtex or more, and the woven fabric is formed by inorganic fibers.

[0009] The gasket made of the fluorine-containing fiber base material of the present application contains a resin, and the resin is a thermosetting resin.

[0010] The fluorine-containing fiber base material of the present application has the advantages of low friction coefficient, good dimensional stability and excellent wear resistance, and the gasket made of the fluorine-containing fiber base material has the advantages of resistance to pressure and shearing, and can be applied in the fields of motor vehicle drive bearings and engineering machinery bearings. BRIEF DESCRIPTION OF DRAWINGS

[0011] Fig. 1 is a structural schematic diagram of the fluorine-containing fiber base material of the present application, in which A is a woven fabric, B is a face thread, and C is a bottom thread, and the face thread B and the bottom thread C are respectively located on both sides of the woven fabric A. DETAILED DESCRIPTION

[0012] The fluorine-containing fiber base material of the present application comprises a woven fabric and face threads and bottom threads fixed on the woven fabric, the face threads are combined twisted yarns formed by fluorine-containing fibers and fibers with tensile strength of 6.6 cN / dtex or more and modulus of 80 cN / dtex or more, and the woven fabric is formed by inorganic fibers. The woven fabric is a base body bearing the face threads and the bottom threads, and compared with knitted fabrics or non-woven fabrics, the woven fabric is arranged with yarns in the warp and weft directions, and the interlaced structure makes the stretching amount of the yarns small, and has excellent dimensional stability. The face threads are thread bundles fixed on the surface of the woven fabric base body, and are also the main body bearing friction, pressure and shearing, and the bottom threads are thread bundles fixing the face threads and adjusting the tightness of the face threads, and the face threads and the bottom threads are matched. If the base material is only formed by a simple woven fabric, the distribution of fibers is basically in the plane of the woven fabric, and the arrangement of fibers in the thickness direction is less. Therefore, when the base material of the present application is subjected to shearing or bending, the base material is easily damaged due to the lack of pressure-bearing fibers.

[0013] In order to meet the requirement of friction, the face yarn must contain fluorine-containing fiber with small friction coefficient, and in order to meet the requirement of pressure resistance and shear resistance, it must contain reinforcing fiber, and further preferably contains high-strength and high-modulus fiber. The high-strength fiber has a tensile strength of preferably 17.6 cN / dtex or more. The higher the strength of the fiber, the less likely it is to be damaged when subjected to tension, and the stronger the shear force that the obtained substrate can withstand when subjected to friction. The high-strength fiber has a modulus of preferably 440 cN / dtex or more. The higher the modulus of the fiber, the smaller the thickness reduction of the obtained substrate when subjected to a certain pressure, and the stronger the load bearing effect. In view of the excellent wear durability of the substrate of the present application, the tensile strength of the high-strength fiber is more preferably 19.0 to 36.0 cN / dtex, and the modulus is more preferably 500 to 1180 cN / dtex.

[0014] In view of the excellent reinforcing property and good compatibility with resin of inorganic fiber, the woven fabric of the present application is formed of inorganic fiber, and in view of the good mechanical strength and resin impregnation property of the woven fabric, the inorganic fiber is preferably glass fiber.

[0015] The fixing method of the face yarn and the bottom yarn on the woven fabric is embroidery, sewing or quilting. Embroidery is a process of embroidering various patterns on the woven fabric by needle thread, forming complex patterns in two-dimensional space, and having unique processing advantages. Therefore, the face yarn and the bottom yarn are preferably fixed on the woven fabric by embroidery, and the yarn that is embroidered into the surface is called embroidery face yarn.

[0016] The woven fabric of the present application does not directly participate in friction, and therefore, the shielding of the woven fabric by the face yarn is very important. The coverage of the face yarn in the embroidered area of the woven fabric is preferably greater than 60%. The coverage refers to the proportion of the area covered by the face yarn to the area of the embroidered area of the woven fabric. If the coverage is too low, the proportion of the woven fabric exposed on the surface is too large. Since the woven fabric does not contain fluorine-containing fiber, when the woven fabric is impregnated with resin to form a composite material, the surface of the woven fabric not covered by the face yarn does not form a lubricating layer during actual friction operation, and this area will be preferentially damaged. From this area, the entire composite material will be worn out, and the service life of the composite material will be reduced. In view of the low friction coefficient of the substrate and the long service life of the composite material, the coverage of the face yarn in the embroidered area of the woven fabric is more preferably greater than 80%.

[0017] The angle between the top layer of the surface thread and its adjacent layer of the surface thread is preferably 70-90°, more preferably 83-90°, and most preferably 90°. The surface of the embroidery needle is the surface, i.e. the embroidery surface, and the embroidery thread has two end points that pierce the woven fabric and combine with the bottom thread. When the surface thread between the two end points is entirely under the woven fabric, the surface thread is the first layer. The surface thread above the first layer is the second layer, and the surface thread above the second layer is the third layer, which is the top layer of the surface thread. The surface thread of the embroidery has a certain tensile strength and rigidity in the axial direction. If the top layer of the surface thread and its adjacent layer of the surface thread are parallel, i.e. the angle is 0-15°, the adjacent two layers of the surface thread can only provide strength in the same direction, which will result in a large difference between the warp strength and the weft strength of the substrate, and the dimensional stability will decrease. In the present application, the closer the angle between the adjacent two layers of the surface thread is to the perpendicular, the smaller the difference between the strength of the substrate in different directions, and the better the dimensional stability.

[0018] The angle between the top layer of the surface thread and the warp yarn of the woven fabric is preferably 0-6° or 84-90°, and the angle between the top layer of the surface thread and the weft yarn of the woven fabric is preferably 84-90° or 0-6°. Since the yarns in the warp and weft directions of the woven fabric are parallel, when the surface thread pierces the woven fabric, it will form a certain angle with the yarns in the warp and weft directions of the woven fabric, i.e. the angle between the surface thread and the warp yarn or weft yarn of the woven fabric. When the angle between the top layer of the surface thread and the yarn of the woven fabric is closer to 0°, the surface thread and the yarn of the woven fabric in one direction will be more parallel, and when the angle is closer to 90°, the surface thread and the yarn of the woven fabric in the other direction will be more perpendicular. At this time, the surface thread has the least impact on the warp-weft interlaced structure of the woven fabric, and the obtained substrate has high dimensional stability and high strength. If the angle is close to 45°, the surface thread and the warp yarn and weft yarn of the woven fabric will be cross-shaped, which will destroy the warp-weft interlaced structure of the woven fabric, and the dimensional stability and strength of the obtained substrate will decrease.

[0019] The fluorine-containing yarn has good chemical resistance and self-lubricating property, but has low strength, and needs to be twisted with other high-strength fibers to improve the strength and wear resistance of the substrate. The twist factor of the twisted yarn is preferably 150-570. If the twist factor is too high, the yarn will be abraded, the roughness will increase, and the friction coefficient of the substrate will increase. If the twist factor is too low, the substrate will not easily form a lubricating layer when subjected to friction, the wear resistance of the substrate will decrease, and the friction coefficient will increase.

[0020] The length of the floating thread of the above-mentioned face thread is preferably 2.0-5.0 mm, where the length of the floating thread refers to the distance between two adjacent needle points of the same face thread on the woven fabric. If the length is too short, in order to maintain the coverage of the face thread on the woven fabric, the embroidery frequency must be increased, which increases the number of face threads and the number of embroidered points in the area of the woven fabric, so that the woven fabric is impacted by the embroidery needle multiple times, resulting in deformation of the woven fabric, and the strength and wear resistance of the base material tend to decrease; if the length is too long, the face thread will swing on the surface of the woven fabric, which will expose the woven fabric under the face thread, and the coverage of the face thread will decrease, and it will be difficult to form a lubricating layer on the surface of the base material, and the wear resistance of the base material will decrease and the friction coefficient will increase. In view of the high wear resistance and low friction coefficient of the base material, the length of the face thread is more preferably 3.0-4.0 mm.

[0021] The distance between the above-mentioned adjacent floating threads is preferably 0.2-2.0 mm, where the distance between the adjacent floating threads refers to the distance between two adjacent face threads in the same direction in the same layer of face thread. If the distance is too short, the density of the face threads distributed in the area of the woven fabric will be high, and the number of needle pricks of the embroidery needle on the woven fabric will be high, which will cause damage to the woven fabric, and will also make it difficult for the liquid resin to enter the gap of the base material, which may result in a decrease in the strength of the gasket and a decrease in the wear resistance of the base material; if the distance is too long, the gap between the adjacent face threads is too large, the face threads are too few, and the strength of the base material is low and the friction coefficient is high.

[0022] The fluorine-containing fiber of the present application is preferably selected from one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyperfluoropropylene, perfluoroethylene propylene copolymer, and polytrifluorochloroethylene polymer fibers, and more preferably polytetrafluoroethylene fiber.

[0023] The high-strength fiber of the present application is preferably selected from one or more of poly-p-phenyleneterephthalamide (para-aramid), polyimide, polyarylate, poly-p-phenylene benzobisoxazole, ultra-high molecular weight polyethylene, and LCP polymer fibers. In view of the strength of the base material and the compatibility with the resin, the high-strength fiber is more preferably poly-p-phenyleneterephthalamide fiber.

[0024] The gasket of the present application is formed by compounding the base material of the fluorine-containing fiber with the resin, and the resin is a thermosetting resin, preferably one of epoxy resin, phenolic resin, polyester resin, vinyl ester, bismaleimide, thermosetting polyimide, cyanate ester, polycarbonate, polyphenyl ether, polysulfone, and polyamide resin. In view of the mechanical properties of the resin itself and the compatibility with the base material, the resin is more preferably epoxy resin.

[0025] The resin content in the gasket of the present application as a fiber-reinforced composite material affects the performance of the gasket. If the content is too low, there will be bubbles or pores inside and on the surface of the gasket, and the uniformity of the pressure bearing of the gasket will decrease. During friction, the resin around the pores may be damaged due to lack of support, and the friction life of the gasket may be reduced. If the content is too high, the excess resin will be distributed on both sides of the gasket, and the excess resin may be worn out during friction due to lack of fiber support, reducing the service life of the gasket. Therefore, the resin content in the gasket is preferably 30-50% by weight, and more preferably 36-46% by weight.

[0026] The thickness retention rate of the gasket of the present application is preferably 90% or more. The thickness retention rate refers to the retention rate of the thickness of the worn position of the gasket after friction under certain pressure, speed and time conditions, and is the most intuitive parameter for measuring the pressure bearing and wear resistance of the gasket. The lower the value, the better the pressure resistance and shear resistance of the gasket.

[0027] The gasket of the present application is preferably a standard circular ring or a circular ring with protrusions on the inner and outer diameters. During use, the circular surface of the gasket is pressed and rubbed, while the inner and outer edges of the circular ring do not participate in the rubbing work, but this part can also play a limiting, fixing or centering role according to the assembly position. Therefore, according to the needs of the use position or scene, special shape changes can be made on the inner diameter and outer diameter of the gasket to achieve the purpose of simplifying the assembly process.

[0028] The gasket of the present application can be applied to the field of motor vehicle drive bearings and engineering machinery bearings.

[0029] The present application is further illustrated by the following examples, but the scope of protection of the present application is not limited to the examples. The various physical property parameters in the examples are measured by the following methods.

[0030]

Tensile strength of fiber

[0031] The bottom thread on the back of the base material is cut off using scissors, and the face thread automatically falls off. The face thread is taken out and twisted together. The twisted yarn is untwisted by a twist meter that meets the GB / T2543.1 standard. The reinforcing yarn in the face thread is obtained, and the tensile strength of the short fibers and long fibers is tested according to the GB / T14337-2022 standard or the GB / T14344-2022 standard, respectively. Five sets of data are measured, and the average value of the strength results of five tests is taken.

[0032]

Modulus of fiber

[0033] The bottom thread on the back of the substrate is cut using scissors, and the face thread automatically falls off. The face thread twist yarn is taken out, and the twist yarn is untwisted by a twist measuring instrument meeting the GB / T 2543.1 standard. The reinforcing yarn in the face thread is obtained, and the tensile strength of the short fibers and long fibers is tested according to the GB / T 14337-2022 standard or the GB / T 14344-2022 standard, respectively. On the tensile strain curve graph, the tangent slope k at the deformation position of 1% is the modulus of the fiber. Five groups of data are measured, and the average value of five test results is taken.

[0034]

Twist factor

[0035] The bottom thread on the back of the substrate is cut using scissors, and the face thread automatically falls off. The face thread twist yarn is taken out, and the fineness of the twist yarn is tested according to the GB / T 14343-2008 standard, and then the twist of the twist yarn is tested according to the GB / T 14345-2008 standard. Five groups of data are tested, and the average values of the fineness T and the twist t are calculated, respectively. The calculation formula of the twist factor of the yarn is as follows: α = t x T 1 / 2 .

[0036]

Coverage rate

[0037] The embroidery area of the substrate surface is photographed by KEYENCE electronic digital microscope, the shooting magnification is 50 times, five different positions are taken respectively, the sum of the areas of the five pictures taken by the lens is calculated and recorded as A0. The exposed woven fabric area is automatically taken by software during the five times of shooting, and the sum of the exposed areas of the five weaves is calculated and recorded as Aa. The calculation formula of the face thread coverage rate is as follows: Φ = (1-Aa / A0) x 100%.

[0038]

Smaller included angle between the top layer of face thread and the adjacent layer of face thread

[0039] The substrate is photographed by KEYENCE electronic digital microscope, the shooting magnification is 20 times, five top layer face threads in the lens are randomly taken, the smaller included angle between the top layer face thread and the adjacent layer face thread is measured and summed as ∠m, and the included angle ∠W between the top layer face thread and the adjacent layer face thread is taken by shooting three times at different positions.

[0040]

Included angle between the top layer of face thread and the warp and weft of the woven fabric

[0041] The substrate is photographed by KEYENCE electronic digital microscope, the shooting magnification is 20 times, five face threads in the lens are randomly taken, the included angle between the extension line of the face thread and the warp of the woven fabric is measured and summed as ∠j, and the included angle between the extension line of the face thread and the weft of the woven fabric is measured and summed as ∠w. Then the included angle ∠J between the face thread and the warp of the woven fabric is ∠j / 15, and the included angle ∠W between the face thread and the weft of the woven fabric is ∠w / 15.

[0042] Length of floating line

[0043] The KEYENCE electronic digital microscope is used to take pictures of the substrate, the magnification is 20 times, the distance between the endpoints of 5 random surface lines in the test lens is measured, a total of 3 times of shooting at different positions are taken, the total distance of the endpoints of the surface lines is calculated as L1, and the calculation formula of the length of the floating line is as follows: L=L1 / 15.

[0044] Distance between adjacent floating lines

[0045] The KEYENCE electronic digital microscope is used to take pictures of the substrate, the magnification is 20 times, the distance between the endpoints of 5 random surface lines in the test lens is measured, a total of 3 times of shooting at different positions are taken, the total distance of the endpoints of the surface lines is calculated as L1, and the calculation formula of the length of the floating line is as follows: L=L1 / 15.

[0046] Friction coefficient of the substrate

[0047] The end face vertical friction and wear tester is used to test the friction of the substrate, 3 substrates are taken, and the friction test is carried out under the conditions of 40MPa and 25mm / s for 5min, and the friction coefficients of the 3 substrates are measured respectively by using the test software, and the average value μ of the friction coefficients of the 3 substrates is calculated.

[0048] Thickness retention rate of the substrate

[0049] The end face vertical friction and wear tester is used to test the friction of the substrate, 3 substrates are taken, and the thickness of the 3 substrates is measured respectively, 5 times are measured, and the average value t1 is calculated, then the 3 substrates are subjected to friction test under the conditions of 40MPa and 25mm / s for 5min, and the thickness of the worn part is measured randomly after the test, 5 times are measured, and the average value t2 is calculated. The calculation formula of the thickness retention rate of the substrate is as follows: L=t2 / t1×100%.

[0050] Deformation rate of the substrate

[0051] 5 substrate rings are taken randomly, the outer diameter is cut completely, and the substrate is laid flat in the 180℃ oven for 20min, then the substrate is taken out, the maximum value and the minimum value of the outer diameter of the 5 substrate rings are measured, and the average value dmax and the average value dmin are taken respectively. The calculation formula of the deformation rate of the substrate is as follows: D=(dmax-dmin) / dmax×100%.

[0052] Resin content

[0053] 5 gaskets are taken randomly, the total mass is measured, which is recorded as m1, the mass of resin in each sample is tested according to the standard of GBT2576-2005, then the total sum of the mass of resin in the 5 samples is calculated, which is recorded as m2, and the calculation formula of the resin content is as follows: K=m2 / m1×100%.

[0054] Thickness retention rate of gasket

[0055] The gasket is tested by using an end face vertical friction and wear testing machine. First, three gaskets are taken, and the thickness of each gasket is measured five times to obtain an average value t1. Then, the three gaskets are subjected to a 5-minute wear test under the friction test conditions of 140 MPa and 25 mm / s. After the test, the thickness of the wear part is randomly measured five times to obtain an average value t2. The calculation formula of the thickness retention rate of the gasket is as follows: L = t2 / t1 x 100%.

[0056] Example 1

[0057] The glass fiber is woven to obtain a glass fiber woven fabric. The polytetrafluoroethylene filament and the para-aramid filament having a tensile strength of 25.0 cN / dtex or more and a modulus of 591 cN / dtex are twisted together to obtain a twist yarn having a twist coefficient of 248. The twist yarn is fixed on the glass fiber woven fabric by embroidery to form a face thread and a bottom thread on the surface and the inside of the woven fabric, respectively, and the face thread is 3 layers. The included angle between the topmost face thread and the adjacent layer of face thread is 90°, and the included angles between the topmost face thread and the warp and weft of the glass fiber woven fabric are 2° / 88°, respectively. The float length of the face thread is 3.5 mm, and the distance between adjacent floats is 0.5 mm. A base material having a face thread coverage rate of 93% in the embroidery area of the glass fiber woven fabric is obtained. The obtained base material is immersed in epoxy resin, and then subjected to pressure, curing, and cutting to obtain a gasket having a gum content of 40% by weight. The properties of the fluorine-containing fiber base material and the gasket of the present application are shown in Table 1.

[0058] Examples 2-20

[0059] The preparation process is the same as that of Example 1, and the specific formulation and properties are shown in Tables 1 and 2.

[0060] The gaskets prepared in Examples 1-20 are applied in the fields of motor vehicle drive shaft bearings and engineering machinery bearing.

[0061] Comparative Example 1

[0062] The glass fiber is woven to obtain a glass fiber woven fabric. The polyester filament and para-aramid filament with tensile strength of 25.0 cN / dtex or more and modulus of 591 cN / dtex are combined to obtain a combined yarn with twist factor of 248. The combined yarn is fixed on the glass fiber woven fabric by embroidery to form surface threads and bottom threads on the surface and inside of the woven fabric, respectively, and the surface threads are 3 layers. The included angle between the topmost surface thread and the surface thread adjacent thereto is 89°, and the included angles between the topmost surface thread and the warp and weft of the glass fiber woven fabric are 2° / 88°, respectively. The float length of the surface thread is 3.5 mm, and the distance between adjacent floats is 0.5 mm. The substrate with a coverage rate of the surface thread of 93% in the embroidered area of the glass fiber woven fabric is obtained. The substrate and the gasket obtained by impregnating the substrate in epoxy resin, followed by pressing, curing and cutting, with a glue content of 40% by weight are obtained. The physical properties of the substrate and the gasket are shown in Table 3.

[0063] Comparative Examples 2-4

[0064] The preparation process is the same as that of Comparative Example 1, and the specific formulation and physical properties are shown in Table 3.

[0065] Comparative Example 5

[0066] The polytetrafluoroethylene filament and para-aramid filament with tensile strength of 24.8 cN / dtex or more and modulus of 579 cN / dtex are combined to obtain a combined yarn with twist factor of 247. The combined yarn is used as warp, and glass fiber is used as weft to weave a woven fabric by 3 / 1 twill double-layer structure. The exposure rate of the combined yarn is measured to be 95%. The woven fabric is impregnated in epoxy resin, followed by pressing, curing and cutting, to obtain a gasket with a glue content of 39% by weight. The physical properties of the substrate and the gasket are shown in Table 3.

[0067] Table 1

[0068] Table 2

[0069] Table 3

[0070] According to the above table:

[0071] (1) According to Examples 1 and 2, under the same conditions, the fluorine-containing fiber in the former is PTFE fiber. Compared with the latter, the friction coefficient of the substrate obtained in the former is lower, and the thickness retention rate of the gasket is higher, i.e., the gasket is resistant to pressure and shear.

[0072] (2) According to Examples 1 and 4, under the same conditions, the twist factor of the combined yarn in the former is within the preferred range. Compared with the latter, the friction coefficient of the substrate obtained in the former is lower, and the thickness retention rate of the gasket is higher, i.e., the gasket is resistant to pressure and shear.

[0073] (3) From Example 1 and Example 5, under the same conditions, the number of surface threads in the former is within the preferred range, and compared with the latter, the distribution of surface threads in the former is more uniform, the strength uniformity is better, the friction coefficient of the obtained substrate is low, the dimensional stability is good, and the thickness retention rate of the gasket is high, that is, the gasket is resistant to pressure and shear.

[0074] (4) From Example 1 and Example 6, under the same conditions, the smaller included angle between the topmost layer of surface threads and the surface threads of its adjacent layer in the former is within the preferred range, and compared with the latter, the surface threads in the former have higher tensile strength and rigidity in the axial direction, the deformation rate of the obtained substrate is small, that is, the dimensional stability is good, and the thickness retention rate of the gasket is high, that is, the gasket is resistant to pressure and shear.

[0075] (5) From Example 1 and Example 7, under the same conditions, the included angle between the topmost layer of surface threads and the warp / weft yarns of the woven fabric in the former is within the preferred range, and compared with the latter, the deformation rate of the obtained substrate is small, the dimensional stability is good, and the thickness retention rate of the gasket is high, that is, the gasket is resistant to pressure and shear.

[0076] (6) From Example 1 and Example 8, under the same conditions, the distance between adjacent floats in the former is within the preferred range, the friction coefficient of the obtained substrate is low, and the thickness retention rate of the gasket is high, that is, the gasket is resistant to pressure and shear.

[0077] (7) From Example 1 and Example 9, under the same conditions, the float length of the surface threads in the former is within the preferred range, the friction coefficient of the obtained substrate is low, and the thickness retention rate of the gasket is high, that is, the gasket is resistant to pressure and shear.

[0078] (8) From Example 1, Example 12, and Example 13, under the same conditions, the coverage of surface threads in the embroidered area of the woven fabric in Example 1 is within the more preferred range, the friction coefficient of the obtained substrate is lower, and the thickness retention rate of the gasket is higher, that is, the gasket is resistant to pressure and shear.

[0079] (9) From Example 1 and Example 14, under the same conditions, the material of the resin in the former is within the more preferred range, and compared with the latter, the thickness retention rate of the obtained gasket is higher, that is, the gasket is resistant to pressure and shear.

[0080] (10) From Example 1 and Example 15, under the same conditions, the content of the resin in the former is within the more preferred range, and compared with the latter, the thickness retention rate of the obtained gasket is higher, that is, the gasket is resistant to pressure and shear.

[0081] (11) From Examples 10, 16 and 17, under the same conditions, the tensile strength of the high-strength fiber in Example 10 is in the more preferable range, the friction coefficient of the obtained substrate is lower, the dimensional stability is better, and the thickness retention rate of the gasket is higher, i.e. the gasket is resistant to pressure and shear.

[0082] (12) From Examples 10, 18 and 19, under the same conditions, the modulus of the high-strength fiber in Example 10 is in the more preferable range, the friction coefficient of the obtained substrate is lower, the dimensional stability is better, and the thickness retention rate of the gasket is higher, i.e. the gasket is resistant to pressure and shear.

[0083] (13) From Examples 17 and 20, under the same conditions, the former contains high-strength and high-modulus fibers in the face thread, compared with the latter, the thickness retention rate of the obtained substrate of the former is high, i.e. the dimensional stability is good and the wear durability is excellent.

[0084] (14) From Examples 1 and Comparative Example 1, under the same conditions, the latter does not use fluorine-containing fibers, compared with the former, the friction coefficient of the obtained substrate of the latter is high, and the thickness retention rate of the gasket is low, i.e. the gasket is poor in pressure resistance and shear resistance.

[0085] (15) From Examples 10 and Comparative Example 2, under the same conditions, the tensile strength and modulus of the fiber in the latter are too low, compared with the former, the friction coefficient of the obtained substrate of the latter is high, and the thickness retention rate of the gasket is low, i.e. the gasket is poor in pressure resistance and shear resistance.

[0086] (16) From Examples 10 and Comparative Example 3, under the same conditions, the woven fabric in the latter does not use inorganic fibers, which have poor combination with resin and low strength, and the thickness retention rate of the obtained gasket is low, i.e. the gasket is poor in pressure resistance and shear resistance.

[0087] (17) From Examples 1 and Comparative Example 4, under the same conditions, the latter uses polyester resin, which belongs to thermoplastic resin, and the thickness retention rate of the obtained gasket is low, i.e. the gasket is poor in pressure resistance and shear resistance.

[0088] (18) From Examples 1 and Comparative Example 5, under the same conditions, the face thread and the bottom thread are not fixed on the woven fabric in the latter, and the woven fabric lacks support in the thickness direction, and the thickness retention rate of the obtained gasket is low, i.e. the gasket is poor in pressure resistance and shear resistance.

Claims

1. A fluorinated fiber substrate, characterized in that: The substrate includes a woven fabric and a top yarn and a bottom yarn fixed on the woven fabric. The top yarn is a twisted yarn formed by fluorinated fibers and fibers with a tensile strength of 6.6 cN / dtex or higher and a modulus of 80 cN / dtex or higher. The woven fabric is formed of inorganic fibers.

2. The fluorinated fiber substrate according to claim 1, characterized in that: The yarn is a twisted yarn formed by fluorinated fibers and fibers with a tensile strength of 17.6 cN / dtex or higher and a modulus of 440 cN / dtex or higher.

3. The fluorinated fiber substrate according to claim 1, characterized in that: The top and bottom threads are fixed to the woven fabric by embroidery.

4. The fluorinated fiber substrate according to claim 3, characterized in that: In the embroidered area of ​​the woven fabric, the coverage of the face thread is greater than 60%.

5. The fluorinated fiber substrate according to claim 3, characterized in that: In the embroidery area of ​​the woven fabric, there are at least two layers of thread, with a small angle of 70 to 90° between the top layer thread and the thread of the adjacent layer.

6. The fluorinated fiber substrate according to claim 5, characterized in that: The angle between the topmost surface line and the surface lines of its adjacent layers is approximately 83–90°.

7. The fluorinated fiber substrate according to claim 5 or 6, characterized in that: The angle between the topmost face yarn and the warp yarn of the woven fabric is 0–6° or 84–90°.

8. The fluorinated fiber substrate according to claim 5 or 6, characterized in that: The angle between the topmost face yarn and the weft yarn of the woven fabric is 84–90° or 0–6°.

9. The fluorinated fiber substrate according to claim 1 or 2, characterized in that: The twist coefficient of the twisted yarn is 150 to 570.

10. The fluorinated fiber substrate according to claim 1, characterized in that: The length of the float of the surface line is 2.0 to 5.0 mm, and the distance between adjacent floats is 0.2 to 2.0 mm.

11. A gasket made from the fluorinated fiber substrate as described in claim 1, characterized in that: The gasket contains thermosetting resin.

12. The gasket according to claim 11, characterized in that: The resin content in the gasket is 36-46% by weight.

13. The gasket according to claim 11, characterized in that: The gasket is in the shape of a standard circular ring or a circular ring with protrusions on its inner and outer diameters.

14. The application of the gasket according to claim 11 in the fields of motor vehicle drive bearings and engineering machinery bearings.

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