A method for testing the bursting strength of textiles

Abstract

The present invention discloses a method for testing the bursting strength of textiles, which relates to the technical field of testing by means of the physical properties of materials, and particularly relates to a testing method for applying stable tension or pressure. The knitted fabric is successively subjected to pre-freezing treatment and cryogenic curing, and after the cryogenic curing is completed, the knitted fabric is cut. The samples obtained by cutting are allowed to warm up and then placed on a fixture for bursting test. The ultra-low temperature changes the movement ability of the fiber molecular segments, making them transform from the rubber state to the glass state, which can increase the hardness and the flatness of the cut, making the edge of the knitted fabric smoother, reducing the offset amount within the structure of the knitted fabric, and being able to reduce the shrinkage rate of the knitted fabric after warming up, solving the problems of edge yarn slippage and deviation of the rupture position in the bursting strength test of knitted fabrics in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of testing by means of material physical properties, and particularly to a testing method for applying stable tension or pressure, and particularly to a testing method for the bursting strength of textiles. Background Art

[0002] The bursting strength test of textiles is a physical index used to evaluate the force that a textile can withstand when it expands until it ruptures under the action of a concentrated load in the form of pushing or pressing. When a local area of a textile is subjected to an external force perpendicular to its plane, it will bulge and expand until it ruptures. This phenomenon is called the bursting of the textile, and the force that the textile withstands at the moment of bursting is the bursting strength. It is an index to measure the resistance of textiles to local vertical force damage. The specific steps of the steel ball method in the bursting strength test are to clamp a sample of a certain area in the circular ring sample of a fixed base, and a spherical ejector rod vertically pushes towards the sample at a constant moving speed, causing the sample to deform until it ruptures, and measuring the bursting strength. By testing the bursting strength of textiles, the bursting resistance performance when they are subjected to external forces can be understood, thereby guiding the design and production of products.

[0003] A knitted fabric is a fabric composed of yarns with a winding relationship. This winding relationship is a stable relationship formed by a group of yarns making left - and - right bending curvilinear motions and adjacent yarns winding and threading through each other. Knitting is a fabric formed by using knitting needles to bend yarns into loops and string them together. In this process, the yarns form loops through the regular movement of knitting, and the loops are strung together with each other to form a knitted fabric.

[0004] In actual tests, cutting the fabric edge easily causes damage to the yarn structure. Especially for elastic or knitted fabrics, the yarns at the cut edge of the sample are prone to slip, affecting the accuracy of the test results. Due to the characteristics of the loop structure of knitted fabrics, they are prone to lateral contraction during the clamping process, resulting in uneven stress on the sample. The final rupture position often concentrates on the edge of the fixture rather than the actual compression area.

[0005] Therefore, it is necessary to improve the bursting strength test method in the prior art to solve the above problems. Summary of the Invention

[0006] The present invention overcomes the deficiencies of the prior art and provides a testing method for the bursting strength of textiles, aiming to solve the problems of yarn slip at the edge and deviation of the rupture position when testing the bursting strength of knitted fabrics in the prior art.

[0007] To achieve the above - mentioned purpose, the technical solution adopted by the present invention is: a testing method for the bursting strength of textiles, comprising the following steps:

[0008] S1: Pre-freeze the knitted fabric for 2 - 3 h, applying a constant tension during the pre-freezing process;

[0009] S2: Deep-freeze and solidify the knitted fabric, with the deep-freezing and solidifying time being 2 - 5 min;

[0010] S3: After the deep-freezing and solidifying treatment, take out the knitted fabric and cut it. After cutting, perform gradient temperature recovery control to obtain a number of specimens;

[0011] S4: Place the specimens on a fixture, start the spherical ejector rod to push towards the specimens until the specimens are broken through, record the maximum bursting strength during the breaking-through process, conduct bursting tests on a number of specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from a number of specimens.

[0012] In a preferred embodiment of the present invention, the spandex content in the knitted fabric is 15 - 20%, and it is a weft knitted fabric.

[0013] In a preferred embodiment of the present invention, the magnitude of the constant tension in S1 is 5 - 8 N / m, and the direction of the constant tension is along the weft direction of the fabric.

[0014] In a preferred embodiment of the present invention, vacuum treatment is performed before the pre-freezing treatment in S1. Specifically, the knitted fabric is placed under a vacuum degree of 0.1 - 0.2 Pa for 30 - 45 min.

[0015] In a preferred embodiment of the present invention, the pre-freezing treatment temperature in S1 is -50 ~ -40 °C, and the pre-freezing treatment is covering with dry ice or placing in a freezer.

[0016] In a preferred embodiment of the present invention, the deep-freezing and solidifying temperature in S2 is -150 ~ -120 °C, and the deep-freezing and solidifying treatment is soaking in liquid nitrogen.

[0017] In a preferred embodiment of the present invention, during the soaking in liquid nitrogen, a load of 20 - 50 g is evenly loaded on one side of the knitted fabric, and the knitted fabric is vertically immersed in liquid nitrogen with the weft direction of the knitted fabric set vertically.

[0018] In a preferred embodiment of the present invention, a titanium alloy blade is used in the cutting process in S3, with the edge pressure being 45 - 60 N / mm 2 , and the blade traveling speed is 12 - 15 mm / s.

[0019] In a preferred embodiment of the present invention, the gradient temperature recovery control in S3 is to first stand still at -80 ~ -70 °C for 30 - 40 min and then raise the temperature to -20 °C at a speed of 0.5 °C / min, and then soak in water at a temperature of 20 - 25 °C for 1 - 2 h and take it out to dry.

[0020] In a preferred embodiment of the present invention, the clamping method of the fixture in S4 is double clamping, including inner ring clamping and outer ring clamping. The shape of the outer ring clamping is square, and the shape of the inner ring clamping is circular.

[0021] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0022] (1) The present invention provides a method for testing the bursting strength of textiles. First, the knitted fabric is pre-frozen and then cryogenically solidified. After the cryogenic solidification is completed, the knitted fabric is cut. The samples obtained by cutting are allowed to warm up and then placed on the fixture for bursting test. The ultra-low temperature changes the movement ability of the fiber molecular segments, making them transform from the rubber state to the glass state. Compared with the existing bursting strength test methods, it can increase the hardness and the flatness of the cut, making the edge of the knitted fabric more flat and reducing the offset amount within the knitted fabric structure. After warming up, it can reduce the shrinkage rate of the knitted fabric, solving the problems of edge yarn slippage and deviation of the rupture position during the bursting strength test of knitted fabrics in the existing technology.

[0023] (2) In the present invention, vacuum treatment is carried out before the pre-freezing treatment in S1. Specifically, the knitted fabric is placed in a vacuum environment with a vacuum degree of 0.1 - 0.2 Pa for 30 - 45 minutes. Impurities such as oxides and dirt on the surface of the knitted fabric in the vacuum environment are effectively removed. Compared with the existing technology, it helps to reduce the influence of these impurities on the frictional force between fibers, thereby reducing the risk of edge yarn slippage.

[0024] (3) In the present invention, during the liquid nitrogen immersion process, a uniform load is applied on one side of the knitted fabric, and the knitted fabric is vertically immersed in liquid nitrogen with the weft direction of the knitted fabric set vertically. Compared with the existing technology, it can effectively stabilize the structure of the fabric and prevent uneven internal stress caused by the free swing or deformation of the fabric during the liquid nitrogen immersion process. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0026] Figure 1 It is a flowchart of the method steps of the preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0029] Weft knitted fabrics are formed by one or several yarns simultaneously and sequentially forming loops along the transverse direction of the fabric by knitting needles, and are strung together longitudinally. Due to the characteristics of its loop structure, weft knitted fabrics usually have good stretchability and extensibility. This elasticity enables weft knitted fabrics to adapt to body movements, providing comfortable wearing experience, and is particularly suitable for making clothing that requires a certain degree of elasticity, such as sportswear, underwear, etc.

[0030] As Figure 1 shown, a method for testing the bursting strength of textiles includes the following steps:

[0031] S1: Pre-freeze the knitted fabric for 2 - 3 h, and apply a constant tension during the pre-freezing process; the constant weft tension aligns the polyurethane molecular chains along the direction of the force, improving the isotropy of subsequent cryogenic treatment, making the material in a metastable state, and providing a structural basis for cryogenic phase transformation.

[0032] S2: Perform cryogenic curing on the knitted fabric, and the cryogenic curing time is 2 - 5 min;

[0033] S3: After the cryogenic curing treatment, take out the knitted fabric and cut it, and then control the gradient temperature recovery to obtain several specimens;

[0034] S4: Place the specimens on the fixture, start the spherical ejector to push towards the specimens until the specimens are burst, record the maximum bursting strength during the bursting process, perform bursting tests on several specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from several specimens.

[0035] The knitted fabric is pre-frozen and cryo-cured successively. After the cryo-curing is completed, the knitted fabric is cut. The samples obtained by cutting are thawed and then placed on a fixture for bursting strength testing. Ultra-low temperature changes the movement ability of fiber molecular segments, making them transform from the rubber state to the glass state, which can increase hardness and cut flatness, make the edge of the knitted fabric smoother and reduce the offset within the knitted fabric structure. After thawing, the shrinkage rate of the knitted fabric can be reduced, solving the problems of edge yarn slippage and deviation of the rupture position in the bursting strength test of knitted fabrics in the prior art textiles.

[0036] Furthermore, the spandex content in the knitted fabric is 15-20%, and it is a weft knitted fabric. Spandex is an elastic fiber, and its molecular segments are in the rubber state at room temperature and have a large elastic deformation ability. Under low-temperature treatment, the molecular segments of spandex transform from the rubber state to the glass state and lose the elastic recovery ability, which helps to reduce the retraction force generated by elastic deformation during shearing. The tear resistance of weft knitted fabrics is generally better than that of other types of fabrics, and it can better resist the bursting action of the punch, reducing the deviation of the rupture position.

[0037] Furthermore, the magnitude of the constant tension in S1 is 5-8 N / m, and the direction of the constant tension is along the weft direction of the fabric. The coil structure in the transverse direction of the weft knitted fabric undergoes uniform tensile deformation, causing the spandex molecules to be oriented along the direction of the force. This pre-oriented structure forms an anisotropy-enhanced "quasi-lattice" after cryo-curing, making the rupture energy more concentratedly transmitted to the test center area. Setting the direction of the constant tension along the weft direction of the fabric helps to form a directional stress distribution inside the fabric. During the bursting strength test, this directional stress distribution can guide the rupture to proceed along a predetermined direction, thereby reducing the deviation of the rupture position.

[0038] Furthermore, vacuum treatment is carried out before the pre-freezing treatment in S1. Specifically, the knitted fabric is placed in a vacuum environment with a vacuum degree of 0.1-0.2 Pa for 30-45 min. In a vacuum environment, impurities such as oxides and dirt on the surface of the knitted fabric are effectively removed, which helps to reduce the influence of these impurities on the friction between fibers, thereby reducing the risk of edge yarn slippage. Vacuum treatment effectively removes gas and water molecules inside the knitted fabric by pumping out air and moisture. This can prevent gas and water molecules from expanding or freezing during ultra-low temperature treatment and damaging the fibers, thereby reducing the deviation of the rupture position. Vacuum treatment helps to make the fiber molecular segments of the knitted fabric in a relatively stable state before pretreatment. This can reduce the violent movement of fiber molecular segments during subsequent ultra-low temperature treatment, help to maintain the integrity of the fiber structure, and thus reduce test errors.

[0039] Furthermore, the pre-freezing treatment temperature in S1 is -50~-40°C, and the pre-freezing treatment is covering with dry ice or placing in a freezer. Low temperature causes changes in the microstructure on the surface of the yarn, such as an increase in the roughness of the fiber surface, thereby increasing the friction between the yarns. This increased friction helps prevent relative slippage of the yarns during the test, further reducing the slippage of the edge yarns.

[0040] Furthermore, the cryogenic curing temperature in S2 is -150~-120°C, and the cryogenic curing treatment is soaking in liquid nitrogen. During the cryogenic curing process, the movement ability of the fiber molecular chain segments decreases, changing from a rubber state to a glass state. This transformation increases the hardness and cut flatness of the fiber, making the edge of the knitted fabric smoother and reducing the offset within the structure.

[0041] Furthermore, during the soaking in liquid nitrogen, a load of 20 - 50 g is evenly loaded on one side of the knitted fabric, and the knitted fabric is vertically immersed in liquid nitrogen with the weft direction of the knitted fabric set vertically. Evenly loading a certain weight of load on one side of the knitted fabric can effectively stabilize the structure of the fabric and prevent uneven internal stress caused by the free swing or deformation of the fabric during the soaking in liquid nitrogen.

[0042] Furthermore, in the cutting process of S3, a titanium alloy blade is used, and the edge pressure is 45 - 60 N / mm 2 , and the blade traveling speed is 12 - 15 mm / s. The titanium alloy blade has high hardness and wear resistance, and can maintain the sharpness and stability of the edge during the cutting process, helping to reduce the friction and resistance during cutting. Setting the edge pressure to 45 - 60 N / mm² can ensure that the blade exerts an appropriate pressure during cutting. This pressure range can not only ensure the smooth progress of cutting but also avoid excessive damage to the knitted fabric. Appropriate pressure helps reduce the slippage of the yarns and the deformation of the fabric. Controlling the blade traveling speed within the range of 12 - 15 mm / s can ensure the smoothness and uniformity of the cutting process. Too fast a traveling speed results in inaccurate cutting or yarn slippage, while too slow a speed increases the cutting time and frictional resistance.

[0043] Furthermore, the gradient temperature recovery control in S3 is to first stand still for 30 - 40 min under the condition of -80~-70°C and then increase the temperature to -20°C at a speed of 0.5°C / min, and then soak in water at a temperature of 20 - 25°C for 1 - 2 h and take it out for drying. Slowly increasing the temperature to -20°C at a speed of 0.5°C / min can gradually release the stress accumulated by the knitted fabric at low temperature. This step helps to avoid internal stress concentration caused by sudden temperature changes in the fabric, thereby reducing the risk of yarn slippage and breakage. Soaking the fabric in water at a temperature of 20 - 25°C for 1 - 2 hours can enable the fiber to gradually recover to its performance state at normal temperature. This step helps to restore the elasticity and toughness of the fiber.

[0044] Furthermore, the clamping method of the fixture in S4 is double clamping, including inner ring clamping and outer ring clamping. The shape of the outer ring clamping is square, and the shape of the inner ring clamping is circular. Through the simultaneous clamping of the inner ring and the outer ring, the double clamping method can fix the knitted fabric more stably and reduce the slipping phenomenon during the test. The circular clamping of the inner ring can provide uniform radial pressure, while the square clamping of the outer ring can prevent the relative movement of the fabric in the test direction. The combination of the two greatly enhances the clamping stability. The square clamping shape can better adapt to the structural characteristics of the knitted fabric, especially in the biaxial tensile test. The square clamping can provide uniform clamping force in four directions, which helps to prevent the slipping of the fabric in any direction during the test. The circular clamping shape can provide a more uniform radial pressure distribution, which helps to reduce the stress concentration inside the fabric. In the bursting strength test, the circular clamping can better simulate the actual situation of the fabric when it is stressed, making the test results closer to the true value.

[0045] The glassy material has higher homogeneity. Pre-freezing and vacuum treatment further reduce the internal defects of the fibers, make the pressure distribution of the fixture more uniform, and avoid the edge loosening caused by local stress concentration.

[0046] The rubbery spandex will generate a retraction force due to elastic deformation during clamping, resulting in continuous dynamic stress in the clamping area and prone to progressive slipping. However, the material in the glassy state has no elastic recovery ability, and the deformation is fixed after clamping, avoiding the slipping caused by the retraction force.

[0047] Example 1

[0048] This example provides a method for testing the bursting strength of textiles, including the following steps:

[0049] S1: Place the weft knitted fabric with 15% spandex content under a vacuum of 0.05 Pa for 45 min, then perform pre-freezing treatment for 2 h. The pre-freezing treatment temperature is -40 °C, and the pre-freezing treatment is covered with dry ice. A constant tension is applied during the pre-freezing treatment, and the magnitude of the constant tension is 6 N / m. The direction of the constant tension is along the weft direction of the fabric;

[0050] S2: Deep-freeze and cure the knitted fabric. The deep-freeze and cure time is 3 min, and the deep-freeze and cure temperature is -120 °C. The deep-freeze and cure treatment is soaking in liquid nitrogen. During the liquid nitrogen soaking process, a load of 40 g is evenly loaded on one side of the knitted fabric, and the knitted fabric is vertically immersed in liquid nitrogen with the weft direction of the knitted fabric set vertically;

[0051] S3: After the deep-freeze and cure treatment, take out the knitted fabric and cut it. The cutting process uses a titanium alloy blade with an edge pressure of 60 N / mm 2, the blade traveling speed is 15 mm / s. After cutting, gradient temperature recovery control is carried out. The gradient temperature recovery control is to first stand still at -70 °C for 40 min and then increase the temperature to -20 °C at a speed of 0.5 °C / min. After that, it is immersed in water at 25 °C for 2 h and taken out for drying to obtain a number of specimens;

[0052] S4: Place the specimen on the fixture. The fixture clamping method is double clamping, including inner ring clamping and outer ring clamping. The shape of the outer ring clamping is square, and the shape of the inner ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken through. Record the maximum bursting strength during the bursting process. Conduct bursting tests on a number of specimens in sequence and calculate the average value of the maximum bursting strengths obtained from a number of specimens.

[0053] Example Two

[0054] This example provides a method for testing the bursting strength of textiles, including the following steps:

[0055] S1: Place the weft knitted fabric with 15% spandex content under a vacuum of 0.1 Pa for 45 min, and then conduct pre-freezing treatment for 2 h. The pre-freezing treatment temperature is -40 °C, and the pre-freezing treatment is covered with dry ice. During the pre-freezing treatment, a constant tension is applied. The magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0056] S2: Conduct cryogenic curing on the knitted fabric. The cryogenic curing time is 3 min, and the cryogenic curing temperature is -120 °C. The cryogenic curing treatment is soaking in liquid nitrogen. During the soaking in liquid nitrogen, a load of 40 g is evenly loaded on one side of the knitted fabric. The knitted fabric is vertically immersed in liquid nitrogen, and the weft direction of the knitted fabric is set vertically;

[0057] S3: After the cryogenic curing treatment, take out the knitted fabric and cut it. During the cutting process, a titanium alloy blade is used, and the edge pressure is 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, gradient temperature recovery control is carried out. The gradient temperature recovery control is to first stand still at -70 °C for 40 min and then increase the temperature to -20 °C at a speed of 0.5 °C / min. After that, it is immersed in water at 25 °C for 2 h and taken out for drying to obtain a number of specimens;

[0058] S4: Place the specimen on the fixture. The fixture clamping method is double clamping, including inner ring clamping and outer ring clamping. The shape of the outer ring clamping is square, and the shape of the inner ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken through. Record the maximum bursting strength during the bursting process. Conduct bursting tests on a number of specimens in sequence and calculate the average value of the maximum bursting strengths obtained from a number of specimens.

[0059] Example Three

[0060] This embodiment provides a method for testing the bursting strength of textiles, including the following steps:

[0061] S1: Place the weft-knitted fabric with 15% spandex content under a vacuum of 0.15 Pa for 45 minutes, then perform pre-freezing treatment for 2 hours at a pre-freezing temperature of -40 °C. The pre-freezing treatment is covered with dry ice, and a constant tension is applied during the pre-freezing process. The magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0062] S2: Deep-freeze and solidify the knitted fabric. The deep-freezing and solidifying time is 3 minutes, and the deep-freezing and solidifying temperature is -120 °C. The deep-freezing and solidifying treatment is soaking in liquid nitrogen. During the liquid nitrogen soaking process, a load of 40 g is evenly loaded on one side of the knitted fabric. The knitted fabric is vertically immersed in liquid nitrogen, and the weft direction of the knitted fabric is set vertically;

[0063] S3: After the deep-freezing and solidifying treatment, take out the knitted fabric and cut it. Use a titanium alloy blade during the cutting process, with an edge pressure of 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, perform gradient temperature recovery control. The gradient temperature recovery control is to first stand still at -70 °C for 40 minutes and then rise to -20 °C at a speed of 0.5 °C / min. Then soak it in water at a temperature of 25 °C for 2 hours and take it out to dry to obtain a number of specimens;

[0064] S4: Place the specimens on the fixture. The fixture clamping method is double clamping, including inner ring clamping and outer ring clamping. The shape of the outer ring clamping is square, and the shape of the inner ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is burst, record the maximum bursting strength during the bursting process, perform bursting tests on a number of specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from a number of specimens.

[0065] Example 4

[0066] This embodiment provides a method for testing the bursting strength of textiles, including the following steps:

[0067] S1: Place the weft-knitted fabric with 15% spandex content under a vacuum of 0.2 Pa for 45 minutes, then perform pre-freezing treatment for 2 hours at a pre-freezing temperature of -40 °C. The pre-freezing treatment is covered with dry ice, and a constant tension is applied during the pre-freezing process. The magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0068] S2: Deep-freeze and solidify the knitted fabric. The deep-freezing and solidifying time is 3 minutes, and the deep-freezing and solidifying temperature is -120 °C. The deep-freezing and solidifying treatment is soaking in liquid nitrogen. During the liquid nitrogen soaking process, a load of 40 g is evenly loaded on one side of the knitted fabric. The knitted fabric is vertically immersed in liquid nitrogen, and the weft direction of the knitted fabric is set vertically;

[0069] S3: After cryogenic solidification treatment, take out the knitted fabric and cut it. During the cutting process, use a titanium alloy blade with an edge pressure of 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, perform gradient temperature recovery control. The gradient temperature recovery control is to first stand still at -70°C for 40 min and then increase the temperature to -20°C at a speed of 0.5°C / min. Then soak it in water at a temperature of 25°C for 2 h and take it out for drying to obtain a number of specimens;

[0070] S4: Place the specimen on the fixture. The fixture clamping method is double clamping, including inner ring clamping and outer ring clamping. The shape of the outer ring clamping is square, and the shape of the inner ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken through, record the maximum bursting strength during the bursting process, and perform bursting tests on a number of specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from a number of specimens.

[0071] Example Five

[0072] This example provides a method for testing the bursting strength of textiles, including the following steps:

[0073] S1: Place a weft knitted fabric with a spandex content of 15% under a vacuum of 0.25 Pa for 45 min, and then perform a pre-freezing treatment for 2 h. The pre-freezing treatment temperature is -40°C, and the pre-freezing treatment is covered with dry ice. During the pre-freezing treatment process, apply a constant tension, and the magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0074] S2: Perform cryogenic solidification on the knitted fabric. The cryogenic solidification time is 3 min, and the cryogenic solidification temperature is -120°C. The cryogenic solidification treatment is soaking in liquid nitrogen. During the soaking in liquid nitrogen, evenly load 40 g of load on one side of the knitted fabric, and vertically immerse the knitted fabric in liquid nitrogen, with the weft direction of the knitted fabric set vertically;

[0075] S3: After cryogenic solidification treatment, take out the knitted fabric and cut it. During the cutting process, use a titanium alloy blade with an edge pressure of 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, perform gradient temperature recovery control. The gradient temperature recovery control is to first stand still at -70°C for 40 min and then increase the temperature to -20°C at a speed of 0.5°C / min. Then soak it in water at a temperature of 25°C for 2 h and take it out for drying to obtain a number of specimens;

[0076] S4: Place the specimen on the fixture. The fixture clamping method is double clamping, including inner-ring clamping and outer-ring clamping. The shape of the outer-ring clamping is square, and the shape of the inner-ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken through. Record the maximum bursting strength during the bursting process. Conduct bursting tests on several specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from several specimens.

[0077] Example Six

[0078] This example provides a method for testing the bursting strength of textiles, including the following steps:

[0079] S1: Place the weft-knitted fabric with 15% spandex content under a vacuum of 0.15 Pa for 45 min, and then conduct pre-freezing treatment for 2 h. The pre-freezing treatment temperature is -40 °C, and the pre-freezing treatment is covered with dry ice. During the pre-freezing treatment, apply a constant tension. The magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0080] S2: Conduct cryogenic curing on the knitted fabric. The cryogenic curing time is 3 min, and the cryogenic curing temperature is -105 °C. The cryogenic curing treatment is soaking in liquid nitrogen. During the liquid nitrogen soaking process, evenly load 40 g of load on one side of the knitted fabric, and vertically immerse the knitted fabric in liquid nitrogen with the weft direction of the knitted fabric set vertically;

[0081] S3: After the cryogenic curing treatment, take out the knitted fabric and cut it. Use a titanium alloy blade during the cutting process. The edge pressure is 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, conduct gradient temperature recovery control. The gradient temperature recovery control is to first stand still at -70 °C for 40 min and then increase the temperature to -20 °C at a speed of 0.5 °C / min. Then soak it in water at a temperature of 25 °C for 2 h and take it out to dry to obtain several specimens;

[0082] S4: Place the specimen on the fixture. The fixture clamping method is double clamping, including inner-ring clamping and outer-ring clamping. The shape of the outer-ring clamping is square, and the shape of the inner-ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken through. Record the maximum bursting strength during the bursting process. Conduct bursting tests on several specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from several specimens.

[0083] Example Seven

[0084] This example provides a method for testing the bursting strength of textiles, including the following steps:

[0085] S1: Place the weft knitted fabric with 15% spandex content under a vacuum of 0.15 Pa for 45 min, then conduct a pre-freezing treatment for 2 h at a pre-freezing temperature of -40 °C. The pre-freezing treatment is covered with dry ice, and a constant tension is applied during the pre-freezing process. The magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0086] S2: Deep-freeze and solidify the knitted fabric. The deep-freezing and solidifying time is 3 min, and the deep-freezing and solidifying temperature is -135 °C. The deep-freezing and solidifying treatment is soaking in liquid nitrogen. During the soaking in liquid nitrogen, a load of 40 g is evenly loaded on one side of the knitted fabric. Immerse the knitted fabric vertically into the liquid nitrogen with the weft direction of the knitted fabric set vertically;

[0087] S3: After the deep-freezing and solidifying treatment, take out the knitted fabric and cut it. Use a titanium alloy blade during the cutting process, with an edge pressure of 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, conduct gradient warming control. The gradient warming control is to first stand still at -70 °C for 40 min and then increase the temperature to -20 °C at a rate of 0.5 °C / min. Then soak it in water at a temperature of 25 °C for 2 h and take it out to dry to obtain a number of specimens;

[0088] S4: Place the specimens on the fixture. The fixture clamping method is double clamping, including inner ring clamping and outer ring clamping. The shape of the outer ring clamping is square, and the shape of the inner ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken through, record the maximum bursting strength during the bursting process, conduct bursting tests on a number of specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from a number of specimens.

[0089] Example 8

[0090] This example provides a method for testing the bursting strength of textiles, including the following steps:

[0091] S1: Place the weft knitted fabric with 15% spandex content under a vacuum of 0.15 Pa for 45 min, then conduct a pre-freezing treatment for 2 h at a pre-freezing temperature of -40 °C. The pre-freezing treatment is covered with dry ice, and a constant tension is applied during the pre-freezing process. The magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0092] S2: Deep-freeze and solidify the knitted fabric. The deep-freezing and solidifying time is 3 min, and the deep-freezing and solidifying temperature is -150 °C. The deep-freezing and solidifying treatment is soaking in liquid nitrogen. During the soaking in liquid nitrogen, a load of 40 g is evenly loaded on one side of the knitted fabric. Immerse the knitted fabric vertically into the liquid nitrogen with the weft direction of the knitted fabric set vertically;

[0093] S3: After cryogenic solidification treatment, take out the knitted fabric and cut it. During the cutting process, use a titanium alloy blade with a cutting edge pressure of 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, perform gradient temperature recovery control. The gradient temperature recovery control is to first stand still at -70°C for 40 min and then increase the temperature to -20°C at a speed of 0.5°C / min. Then soak it in water at a temperature of 25°C for 2 h and take it out to dry to obtain a number of specimens;

[0094] S4: Place the specimen on the fixture. The fixture clamping method is double clamping, including inner ring clamping and outer ring clamping. The outer ring clamping shape is square, and the inner ring clamping shape is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken through, record the maximum bursting strength during the breaking process, and perform bursting tests on a number of specimens in sequence, and calculate the average value of the maximum bursting strength obtained from a number of specimens.

[0095] Example Nine

[0096] This example provides a method for testing the bursting strength of textiles, including the following steps:

[0097] S1: Place the weft knitted fabric with a spandex content of 15% under a vacuum of 0.15 Pa for 45 min, and then perform pre-freezing treatment for 2 h. The pre-freezing treatment temperature is -40°C, and the pre-freezing treatment is covered with dry ice. During the pre-freezing treatment process, apply a constant tension, and the magnitude of the constant tension is 6 N / m, and the direction of the constant tension is along the weft direction of the fabric;

[0098] S2: Perform cryogenic solidification on the knitted fabric. The cryogenic solidification time is 3 min, and the cryogenic solidification temperature is -165°C. The cryogenic solidification treatment is soaking in liquid nitrogen. During the liquid nitrogen soaking process, evenly load 40 g of load on one side of the knitted fabric, and vertically immerse the knitted fabric in liquid nitrogen with the weft direction of the knitted fabric set vertically;

[0099] S3: After cryogenic solidification treatment, take out the knitted fabric and cut it. During the cutting process, use a titanium alloy blade with a cutting edge pressure of 60 N / mm 2 , the blade traveling speed is 15 mm / s. After cutting, perform gradient temperature recovery control. The gradient temperature recovery control is to first stand still at -70°C for 40 min and then increase the temperature to -20°C at a speed of 0.5°C / min. Then soak it in water at a temperature of 25°C for 2 h and take it out to dry to obtain a number of specimens;

[0100] S4: Place the specimen on the fixture. The clamping method of the fixture is double clamping, including inner-ring clamping and outer-ring clamping. The shape of the outer-ring clamping is square, and the shape of the inner-ring clamping is circular. Start the spherical ejector rod to push towards the specimen until the specimen is broken. Record the maximum bursting strength during the bursting process. Conduct bursting tests on several specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from several specimens.

[0101] Comparative Example 1

[0102] This comparative example provides a method for testing the bursting strength of textiles, including the following steps:

[0103] S1: Cut the weft knitted fabric with 15% spandex content. Use a titanium alloy blade during the cutting process. The edge pressure is 60 N / mm 2 , and the blade traveling speed is 15 mm / s to obtain several specimens;

[0104] S4: Place the specimen on the fixture. Start the spherical ejector rod to push towards the specimen until the specimen is broken. Record the maximum bursting strength during the bursting process. Conduct bursting tests on several specimens in sequence, and calculate the average value of the maximum bursting strengths obtained from several specimens.

[0105] Conduct bursting strength tests on the test methods of Examples 1 to 9 and Comparative Example 1 respectively, and compare the sample slip amount and the deviation amount of the rupture position during the test. When sampling the sample slip amount, spray 4 fluorescent marking points symmetrically on the outer edge of the specimen. The marking point positions are: 0°, 90°, 180°, 270°. Record the displacement of the marking points throughout the bursting test. Calculate the radial slip amount with the geometric center of the specimen as the coordinate origin. The slip amount is the maximum value of the displacements of the 4 marking points at the moment of bursting. The slip amount calculation formula is , is the maximum value of the displacement of each marking point, i is the marking point label, (x0, y0) and (x i , y i ) are the initial marking point coordinates and the displacement maximum value coordinates respectively, and take the average value of the slip amount to obtain the sample slip amount; the deviation amount of the rupture position is the deviation distance between the rupture position and the predetermined center. The sample slip amount and the deviation amount of the rupture position are shown in Table 1.

[0106] Table 1 Data of sample slip amount and deviation amount of rupture position for Examples 1 to 9 and Comparative Example 1

[0107]

[0108] As can be seen from Table 1, the sample slip amount and the deviation amount of the rupture position of Examples 1 to 9 are both smaller than those of Comparative Example 1, and can have better anti-slip performance and rupture position accuracy, showing superiority.

[0109] In Examples 1 to 5, as the vacuum degree gradually increases, the sample slippage and the rupture position deviation first decrease and then increase, and the anti-slip performance and the rupture position accuracy first increase and then weaken. This is because as the vacuum degree gradually increases, the vacuum treatment can make the fabric more evenly stressed during the test, reduce the stress concentration phenomenon caused by the uneven fabric structure, and improve the accuracy and reliability of the test results. When the vacuum degree is too low, the moisture in the fiber will form ice crystals during the cooling process, and the fiber performance will be affected when it is warmed up, causing the internal defects of the fiber to increase. When the vacuum degree is too high, the air inside the fabric will be excessively extracted, resulting in reduced elasticity between the fibers, and poor flexibility and adaptability of the fabric. When stressed, the fabric cannot disperse stress as evenly as it does under a lower vacuum degree, and the stress concentration phenomenon in some areas is aggravated, thereby affecting the accuracy of the test results. The preferred embodiment is Example 3.

[0110] In Example 3 and Examples 6 to 9, as the temperature of cryogenic solidification decreases, the sample slippage and the deviation of the fracture position first decrease and then increase, and the anti-slip performance and the accuracy of the fracture position first increase and then weaken. This is because during the cryogenic solidification process, as the temperature decreases, the fabric fibers will shrink and rearrange, which helps the fibers to be arranged more tightly and orderly, and can reduce residual stress, which helps to improve the stability and uniformity of the fabric, thereby enhancing the anti-slip performance and the accuracy of the fracture position, thereby reducing the slippage of the fabric when it is stressed and the deviation of the fracture position. However, when the temperature is too low, the fibers will become too fragile and brittle, making it easier to break and slip locally when stressed, and will cause new residual stress to be generated, which is not conducive to the performance of the fabric, thereby increasing the slippage and the deviation of the fracture position. The preferred embodiment is Example 7.

[0111] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for testing the bursting strength of a textile, characterized in that: The following steps are involved: S1: pre-freezing the knitted fabric for 2-3 hours, applying constant tension during the pre-freezing process; the spandex content in the knitted fabric is 15-20%, and the knitted fabric is a weft knitted fabric; vacuum treatment is performed before the pre-freezing process, specifically, the knitted fabric is placed in a vacuum degree of 0.1-0.2 Pa for 30-45 minutes; S2: subjecting the knitted fabric to cryogenic curing, wherein the cryogenic curing time is 2-5 minutes; S3: After the cryogenic solidification treatment, the knitted fabric is taken out and cut, and after cutting, a gradient temperature recovery control is performed to obtain a plurality of samples; S4: Place the sample on the fixture, start the spherical push rod to push the sample until the sample is broken, record the maximum bursting strength during the bursting process, perform bursting tests on several samples in turn, and calculate the average value of the maximum bursting strengths obtained for several samples.

2. A method for testing the bursting strength of textiles according to claim 1, characterized in that: The constant tension in S1 is 5-8 N / m, and the direction of the constant tension is along the weft direction of the fabric.

3. A textile bursting strength testing method according to claim 1, characterized in that: The pre-freezing treatment temperature in S1 is -50 to -40°C, and the pre-freezing treatment is covered with dry ice or placed in a freezer.

4. A method for testing the bursting strength of textiles according to claim 1, characterized in that: The cryogenic solidification temperature in S2 is -150 to -120° C., and the cryogenic solidification treatment is liquid nitrogen immersion.

5. A method for testing the bursting strength of textiles according to claim 4, characterized in that: During the liquid nitrogen immersion process, a load of 20-50 g is evenly loaded on one side of the knitted fabric, and the knitted fabric is vertically immersed in the liquid nitrogen, with the knitted fabric being arranged vertically in the weft direction.

6. A method for testing the bursting strength of textiles according to claim 1, characterized in that: The cutting process in S3 uses a titanium alloy blade with a blade edge pressure of 45-60N / mm 2 , the blade travel speed is 12-15mm / s.

7. A method for testing the bursting strength of textiles according to claim 1, characterized in that: The gradient temperature recovery in S3 is controlled by first standing at -80~-70°C for 30-40 minutes and then heating to -20°C at a rate of 0.5°C / min, then soaking in water at a temperature of 20-25°C for 1-2 hours and taking out to dry.

8. A method for testing the bursting strength of textiles according to claim 1, characterized in that: The clamping method of the clamp in S4 is double clamping, including inner ring clamping and outer ring clamping, the outer ring clamping shape is square, and the inner ring clamping shape is circular.

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