The necessity of rubber flame retardant With the continuous advancement of technology, rubber products have been widely used in various industries. Wire and cable, rubber rope, conveyor belt, rubber hose, air duct, rubber belt, and rubber products used in the electrical and electronic industry must meet the corresponding national standards in terms of flame retardancy and mechanical properties. The requirements for flame retardant properties of rubber products are also increasing, and the development and application of flame retardant rubber has become particularly important. There are many types of rubber, and various rubbers have different combustion properties. Most of the rubbers have a low oxygen index and a low decomposition temperature, which is easy to burn. Therefore, it has become the main way to prepare flame retardant rubber by researching on rubber burning characteristics, adding flame retardant or improving the burning performance of rubber itself. Several important ways of rubber flame retardant The main way of flame retardant is to slow down the thermal decomposition and block the combustion process. The specific flame retardant routes are as follows: The addition of one or more substances changes the thermal decomposition behavior of the rubber, so that the prepared rubber has a high thermal decomposition temperature and reduces the flammable gas generated by the decomposition. The added substance can generate a non-combustible gas when heated, or produce a viscous substance that is isolated from O2, or can absorb heat when heated, so that the three elements of combustion (combustible, oxygen, reach the ignition point) cannot be satisfied. Add substances that can capture HO·, interrupt the chain reaction, and terminate the flame propagation. Change the structure or properties of the rubber molecular chain, improve the thermal decomposition ability or make itself has flame retardant. Due to the good compatibility between rubber and various additives, the addition of various flame retardants is still an important means of flame retardant modification of rubber.

Balance is a commonly used equipment in laboratory. How to use balance correctly has an important influence on the accuracy of experimental data. As the precise instruments, if we can operate and maintain it well, then will keep the live of balance. Instrodction 01 Relative terms Peeling device: device that sets the indication value to zero when there is load on the flat scale on the same day. Multi-scale: there is only one scale range, divided into several local scale ranges according to different actual scale values.The local weighing range is automatically determined according to the increase or decrease of the loaded load. For example, the scale range of a certain balance is 0-420g, the weighing range is 0-200g, the actual dividing value of the balance is 0.0001g, and the weighing range is 200-420g, the actual dividing value of the balance is 0.001g. Maximum weighing: the maximum weighing capacity when tare is added is not included. Minimum weighing: when the load is less than that, the weighing result may produce too large relative error. Actual dividing value (d) : refers to the difference between two adjacent indicating values. Calibration scale value (e) : the value in units of mass used for grading the balance and metrological verification. Test score (n) : the ratio of the maximum weight to the test score. 02 scale grade The balance is divided into four grades according to the verified degree value e and the verified degree n. Meanwhile, the accuracy level of the balance also meets the corresponding relationship with e and n, as shown in table 1. Table 1 relationship between balance accuracy level and e and n Note: in the last column of the above table, except for the special accuracy grade balance with e < 1mg, d is used to calculate the minimum weight in place of e. 03 Balance error Different scales have different maximum allowable errors (MPE), and the same scale has different maximum allowable errors in different scales. The relationship between the maximum allowable error and the scale level and weighing range is shown in table 2. Table 2 relationship between the maximum allowable error and balance level and weighing range. Use of balance Application notice： 1. Observe the level device of the balance and check whether the balance is level. Balance of balance can be adjusted by adjusting the foot bolt of balance. 2. After power failure for a long time, start the machine for preheating for 30min. If no power failure occurs, start the machine directly for use. 3. Open the windproof cover of the balance, put it into the weighing paper, and after the indication is stable, press the "clear zero" button to close the windproof cover, and observe whether the indication of the balance is zero. If not, press the "clear zero" button until the indication is zero. 4. Open the windproof cover, put the articles to be weighed on the balance, close the windproof cover, and read the indicator number after the indicator number of the balance is sta...

What is the Breaking strength and Elongation at break? Definition: Breaking Strength：In the process of tensile testing under specified conditions, The ratio of the maximum force recorded by the specimen being pulled to the linear density,See ordinate 1 in below picture. Elongation at break: The elongation of the specimen under the action of maximum force, as shown the abscissa 4 in above picture. What is the relationship between them? Breaking strength and elongation at break are two important physical quantities that represent the mechanical properties of textiles or fabrics. The fracture of textiles with a small range of yield belongs to the classical theory of linear elastic fracture mechanics. The fiber in the yarn is affected by various factors in the textile process, which makes the yarn have invisible cracks. When the yarn is woven into the fabric, it will be pulled by certain external forces, and these cracks will be enlarged macroscopically, which will cause the fabric to break or tear. So textiles or fabric rupture strength and the degree of density, thickness of yarn and spinning technology has a direct relationship, and elongation at break is essentially depends on the types of fiber, for the high Young's modulus of fiber its corresponding high elongation at break, second fiber morphology, degree of orientation and crystallization degree also can have a certain effect. The Difference? Perhaps many people wonder: what is the difference between breaking strength and tearing strength?Breaking strength measures the force required to produce a tear in the fabric; and tear strength is the force required to further tear the crack under the external force.Both of them are important mechanical indexes, which are related to each other and different from each other. There are many methods for breaking strength testing, such as the strip method and catch sample method.We will introduce the bar test method, the test standards:ISO13934-1 《Textiles— Tensile properties of fabrics— Part 1: Determination of maximum force and elongation at maximum force using the strip method》 GESTER tensile testing machine for fabric strip method is used for testing mechanical properties of various textiles, such as stretch, tear, top break, constant elongation, constant load, elasticity, seam slip, stripping, etc.And widely used in rubber, plastic, leather, metal, wire, paper, packaging, building materials, petrochemical, electrical, geotechnical materials tensile, compression, bending, bonding, stripping, tearing, breaking, creep test force value, elongation, deformation test. Testing range: 10N, 20N, 50N, 100N, 200N, 500N, 1KN, 2KN, 5KN optional. Test results: Sample from the jaw fracture within 5 mm, as jaw fracture, when finished 5 pieces of sample design, if the value is greater than the smallest jaw fracture "normal" can be preserved, if less than the minimum "normal" should be abandoned, plus a test to get five "normal", if all test results are jaw fracture, sh...

Rubber in the process of thermal oxidative aging : The types of structural changes of rubber in the process of thermal oxidative aging can be divided into: One is the thermal oxidative aging reaction (pyrolysis) which is based on molecular chain degradation. The second type is pyrolysis (structured), which is mainly cross-linked between molecular chains. Natural rubber contains isoprene rubber, butyl rubber, diethylene propylene rubber, homopolymer chlorohydrin rubber and copolymer chlorohydrin rubber, etc. The appearance of this kind of rubber will become soft and sticky after thermal oxygen aging. The main change for Butadiene-containing butadiene rubber in the thermal oxygen aging process is the cross-linking reaction. Such as NBR/SBR/CR/ERDM/FPM/CSM will also have similar changes. The appearance of this kind of rubber is hard and brittle after thermal aging. The main factors which influences the rubber aging: 1. Oxygen: Oxygen has a free radical chain reaction with rubber molecules in rubber, and the molecular chain is broken or excessively cross-linking, which results to change in rubber properties. Oxidation is one of the important reasons for rubber aging. 2.Ozone: The chemical activity of ozone is much higher than that of oxygen, and it is more destructive. It also breaks the molecular chain, but the effect of ozone on rubber varies from whether the rubber is deformed or not. When it is used as a rubber for deformation (mainly unsaturated rubber), a crack which is straight in the direction of stress is generated, that is, "ozone cracking"; when it acts on a deformed rubber, only an oxide film will be formed on the surface and without cracking. 3. Heat: Increasing the temperature can cause the rubber thermal cracking or thermal cross-linking.But the basic function of heat is activation. Increasing oxygen diffusion rate and activation oxidation reaction in order to accelerate the rubber oxidation reaction rate, which is a common phenomenon of aging - thermal oxygen aging.   4.Mechanical stress: Under the repeated action of mechanical stress, the rubber molecular chain will be broken and to form a  free chain, and then trigger oxidation chain reaction and form a mechanochemical process. Between mechanical fracture molecular chain and mechanical activation oxidation process, which one takes advantage depending on the conditions.In addition, it is easy to cause ozone cracking under stress. 5. Water: There are two functions of water:  In the humid environment or long-term immersion in water, rubber is easy to damage. This is due to rubber water-soluble substances and hydrophilic groups and other components by water extraction solution, hydrolysis or absorption and other reasons.Especially in the alternate action of water immersion and atmospheric exposure, it will accelerate the destruction of rubber.However, in some cases, the water will not have destructive effect on the rubber, and may even delay the aging effect. 6. Oil: In the pr...

Air permeability refers to the permeability of polymer materials. Such as films, coatings, and fabrics. Permeability of fabric refers to give pressure difference across fabric to test air passing performance. The rate of flow of air passing perpendicularly through a give area of fabric is measured at a given pressure difference across the fabric test area over a given time period. The common unit is mm/s. Because pressure difference is the necessary condition for airflow. Only when pressure difference keep, air can be flowed on the fabric. Air permeability will affects the wear comfort of the fabric. Such as thermal insulation and warmth. Permeability of fabric an important way for the body to spread out heat, gaseous moisture and carbon dioxide. Standards for Permeability of fabric: GB/T 5453, ISO 9237,ASTM D737, JISL1096.Machine: Automatic Air Permeability Tester. Fabric factor and environmental factor will affect the permeability of fabric. Fabric factor Fiber morphology and yarn structure: When the linear density of the warp and weft yarns and the density of warp yarn arrangement are the same, the shaped fiber fabric is superior to the circular cross-section fiber fabric, the permeability of single fiber coarser in the fabric is better than the single fiber fine. Fabric structure: Under the same arrangement density and tightness, strength of permeability as follows: plain weave

After enter autumn, The weather is getting cooler and the rains more frequently.When you want to traveling.You need prepare the rain and typhoon, also have to consider wearing clothes with good moisture permeability. Generally speaking. Standard definition of a jacket: Adopt the textile fabrics with waterproof and moisture permeable. Processed into outdoor sports, with waterproof and moisture permeable clothing. How to judge the waterproof, moisture permeability of clothes? Here GESTER introduce the common standard test method of waterproof and moisture permeable clothing fabrics. Waterproof Performance Clothing water resistance refers to the resistance of clothing to external water with certain pressure or rain water with certain kinetic energy as well as to liquid water such as snow, dew and frost outside various clothing. Assessment indicators are :Surface moisture resistance, hydrostatic pressure. 1.Surface moisture resistance 《Textiles - Testing and evaluation for water resistance - Spray test method》 :Principle of test: spray a certain amount of water on the surface of the sample under specified conditions, and observe the wetting condition of the sample. The results were compared with the standard sample cards, and the closest sample level was used as the water repellent level.Level 5 is the best and level 1 is the worst. Water repellency tester Water-repellent grading chart: Note: the anti-wetting performance can only be achieved if the water level reaches level 3. 2.Hydrostatic pressure 《Textiles - Testing and evaluation for water resistance - Hydrostatic method》 Simulation of outdoor raindrops continued wet environment.Use the hydrostatic pressure of the fabric is used to represent the resistance of water through the fabric.Under standard atmosphere, the sample is subjected to rising water pressure on one side until three seepage points appear on the other side,record the current pressure at the third seepage point. Hydrostatic Head Tester Test phenomenon: Note: Generally, products with high hydrostatic pressure resistance are coated fabrics or coated fabrics, which do not perform well in hand feel, air permeability and moisture permeability. GESTER is leading and outstanding company in manufacturing and supplying a wide range of textile testing equipment. Our machines all meet with: ISO, ASTM, AATCC, BS, EN, DIN, JIS and other requireable standards.

Concerning the comfort and safety, the focus on performance of footwear slip resistance is becoming more and more stressed nowadays. This essay, based on the domestic and abroad researches, put emphasis on the main factors which influence the footwear slip resistance. Together with the testing machine and testing method to assess the performance of footwear slip resistance, it also gives some suggestions on how to improve the the test method and how to perfect the slip resistance. 1.The influencing factors The performance of slip resistance is one of the most important physical project which involved in the sole material quality and wearing safety & health & comfort property. In recent years, European Union and the relevant organizations in the United States are extremely concerned about the potential damage that caused by the failure of slip resistance performance. Many shoes which sells on the market has been recalled because of the unqualified slip resistance performance, mainly related to children’s shoes, plastic shoes and other shoes. 2.Description on Performance of Slip Resistance When walking, the foot (shoes) will pause for a moment on the ground where it landed. There is a coefficient of static friction (SCOF) between the sole and the road. If the SCOF is too small, the foot will slide on the ground, there will be a dynamic friction coefficient (DCOF) between the sole and the ground. If the value of DCOF is enough to prevent this kind of sliding of the shoes, the probability of slipping or falling will not occur or the occurrence is small, so safe walking requires the shoes to be subjected to the traction force which is not greater than the friction force it receives. According to Newton's second law, when the pressure is constant, the frictional force of the shoe depends on the friction coefficient. Therefore, the friction coefficient becomes the evaluation standard for the anti-slip performance. 3.Test Method for Footwear Slip Resistance There are many test methods for friction coefficient, and the shoe slip resistance tester is also various. According to the test principle of friction coefficient, the anti-slip performance method can be divided into horizontal bottom plate oblique thrust method, horizontal bottom plate drag method, tilt angle test method and Pendulum measurement method 4 categories. 3.1 Principle and Measuring Method of Horizontal Floor Oblique Thrust Method 3.1.1 James slip resistance tester The test method for the James anti-slip performance tester is specified in ASTM F489-96 "Testing Methods for Using James Machines" and ASTM D2047-99 "Test Method for Measuring Static Friction Coefficient of Floor Surfaces Using Brighteners with James Machines". As a hinge strut slip tester, the James machine applies a constant vertical pressure on the flat tested specimen and then gradually increases the lateral thrust until it is slipped. At this time, the lateral force is the measured sliding static friction and its ra...

Why the high heels are not stable and cause the fall down? As a consumer, when choose shoes, if unqualified steel shanks will greatly reduce the comfort degree and safety factor of leather shoes.  What is the shoe steel Shank? The footwear steel shank is a shoe (boot) made of a metal material. Most male/female shoes have a steel shank that is placed between the outsole and the insole at the center of the foot. We can't directly see the shoe steel shank from the outside, but it plays an important role in the quality of leather shoes, especially medium and high-heeled shoes. Shank Type:  1.By users: men's shoes shank, women's shoes shank, children (big children) shoes shank; 2.By steel shank shape: I-shaped shank, Y-shaped shank, L-shaped shank (L type is used for women's high heels, the back part is bent downward to form the short side embedded in the bottom of the molding), as shown below: The Importance for steel shank The steel shank is one of the main force-receiving parts of the shoe, which plays an important role in maintaining the curvature and stability of the sole by connecting the heel and the forefoot in the sole. The shoe shank determines whether the shoes are stable on the feet. It not only needs to have enough strength and rigidity to support the appearance of the leather shoes, but also needs a certain flexibility to meet the comfort of wearing. The shank is too soft, the heel will be forward/backward or left/right skewed when walking, making the overall shape of the shoes very ugly, wearing unstable, lame, long time, will make the waist, legs and feet I feel tired. If the steel shanks are too hard, it will cause uncomfortableness. In the case of instability of gait, the heel is easily broken by external impact. When wearing it, it feels slippery underfooting and fits the feet imperfectly, and may even cause injury. In a word, the safety of shoes depends on the quality of steel shanks. For the quality of steel hooked heart, the relevant testing standards have been introduced in China, GB/T 28011-2011 "Steel shanks of shoes" standard. Although the mandatory standard has been changed to recommendation standard, its role in improving the safety of shoes still exists. Technical Requirements for Main Projects of Steel Hooked Heart of Footwear. The quality of GB/T 28011-2011 "Steel Shanks of Footwear" is divided into external quality and internal quality. External quality includes sign, appearance, length, width and thickness. The internal quality includes longitudinal stiffness, fatigue resistance, hardness and bending performance, among which longitudinal stiffness, fatigue resistance, hardness and bending performance are important safety indicators. How to know if the steel shanks is up to standard? Please choose GESTER Footwear Testing Equipments to test for your steel shanks or other shoes prodcuts. 1, Steel shanks hardness test - Automatic Digital Rockwell Hardness Tester GT-HRS...