1、 physical and chemical properties

Usually we are talking about natural rubber, refers to the rubber from the collection of natural latex, the solidification, drying and other processing processes made of solid. Natural rubber is made from latex of trilobite, and the chemical name of the polymer is polyisoprene. Polyisoprene can also be polymerized from its rubber matrix monomer. Natural rubber has many excellent physical properties; rebound rate of 0-100 ℃ up to 50% -80%, elongation of 1000 ℃, pure rubber tensile strength of 17-25Mpa, carbon black reinforced vulcanization Glue up to 25-35Mpa, 500% of the fixed tensile strength of 12Mpa above, good air tightness, shaking parameters of 2.969 * 10H2 (s.Pa) and SBR similar to its shortcomings is not resistant to hydrocarbon oil, not suitable for ultraviolet , Oxygen, ozone. But its poor weather resistance can be improved by special additives.

1) Physical properties of natural rubber

Natural rubber at room temperature with high elasticity, slightly plastic, with a very good mechanical strength, low loss of hysteresis, in a number of deformation when the heat is low, so its resistance to flexability is also very good, and because it is non-polar Rubber, so electrical insulation performance is good.

2) Chemical properties of natural rubber

Because there are unsaturated double bonds, natural rubber is a strong chemical reaction material, light, heat, ozone, radiation, flexing deformation and copper, manganese and other metals can promote the aging of rubber, aging is natural rubber Of the natural weakness, but added antioxidant natural rubber, sometimes exposed to sunlight in the sun for two months still can not see much change in the warehouse after three years of storage can still be used as usual.

3) natural rubber resistance to media characteristics

Natural rubber has a good alkali resistance, but intolerant strong acid. Since the natural rubber is a non-polar rubber, it can only resist some polar solvents and swell in non-polar solvents. Therefore, its oil resistance and solvent resistance are poor. Generally speaking, hydrocarbons, halogenated hydrocarbons, , Ethers, higher ketones and higher fatty acids have a dissolution effect on natural rubber, but their solubility is affected by the degree of plasticity, while low-grade ketones, lower-grade vinegar and alcohols are non-solvents for natural rubber.

2、 natural rubber varieties classification and quality standards

Natural rubber can be divided into two categories according to the form: solid natural rubber (film and granule) and concentrated latex. In daily use, solid natural rubber accounted for the vast majority of the proportion.

Film according to the manufacturing process and the appearance of different, can be divided into smoke film, air-dried film, white wrinkles, brown wrinkles and so on. Smoke stickers are the most representative varieties of natural rubber, has been a large amount of large, widely used in a plastic species, smoke tablets generally according to the shape to grading, divided into premium, one, two, three, four , Five and so on a total of six, less than five are listed as outside the plastic.

The physical and chemical properties include the impurity content, the plastic initial value, the plastic retention rate, the nitrogen content, the volatile matter content, the ash content and the color index, and so on. The physical and chemical properties of the granules are as follows: Item, which is the dominant content of impurity content, according to the number of impurities divided into 5L, 5,10,20 and 50, a total of five levels.

3、the temperature range

-50 ℃ ~ 70 ℃, (short time up to 100 ℃)

4、hardness range

Shore A40 degrees to 90 degrees

5、color

Black, can also be specified by the customer color

6、application

Because natural rubber has the above series of physical and chemical characteristics, especially its excellent resilience, insulation, water and plasticity and other characteristics, and after appropriate treatment also has oil, acid, alkali, heat, cold, pressure , Wear and other valuable properties, so with a wide range of uses. Such as the daily life of the rain boots, warm water bags, elastic band; medical and health industry used by the surgeon gloves, blood vessels; transport with a variety of tires; industrial conveyor belt, conveyor belt, acid and alkali gloves; Agriculture, the use of irrigation and drainage hose, ammonia pockets; weather measurement with sounding balloons; scientific test with the seal, shock equipment; defense on the use of aircraft, tanks, artillery, gas masks; or even rockets, artificial earth satellites and spacecraft Sophisticated scientific and technological products indispensable raw materials. At present, the world part or completely made of natural rubber has reached more than 70,000 kinds of items.