Small knowledge about rubber

A, the formation of raw rubber:
Raw rubber respectively for the natural rubber and synthetic rubber in two categories:
: 1. The natural rubber of rubber tree cutting mouth, collect the outflow of mucilage, through to the impurities, solidification, smoked, drying and processing procedures, and form the raw rubber materials.
2. The synthetic rubber: by-products produced by petrochemical industry, according to the different needs of different physical properties of raw rubber material synthesis.Commonly used such as SBR, NBR, EPDM, BR, IIR, CR, Q, FKM, etc.But because of difference of synthetic method, the similar rubber can separate several different kinds of raw rubber, and through a set of formula, any type rubber, all can change thousands one hundred can meet the demand of products of raw rubber materials.

second, the configuration of the rubber raw materials:
The configuration of the rubber raw materials can be divided into three basic process:
Plastication: practice is to put the raw rubber plastic shear, raw rubber and plastic, homogenization, practice homework help mixed chelating agent.Its effect is to improve drug dispersed, prevent the friction heat, homework and rubber scorch occur, thus change the rubber processability.
Mixing: 2. The practice is to cooperate with drug mixed evenly mixed with the molding of raw rubber, and mixing quality, directly affect the products good or not.Drugs distributed unevenly, the molecular structure can't completely crosslinking, rubber cannot reach the ideal property.
3. Delivery: mixing of raw rubber, pressed out the homework, the rubber contains excess air pressure, and complete the required thickness, to facilitate the molding operation within the mould.

Three, rubber molding:
Molecular structure of raw rubber elastomer for unsaturated long key, so forming elements, needs to have proper drug additives and the external environment factors (such as time, temperature, pressure, etc.), the unsaturated bond damage, again for saturated bond, and assisted by vacuum, will contain air out completely.So, just can make the rubber molding, play its proper characteristics.If there is any missing its forming process, such as formulation, such as error and improper time and temperature), can cause property loss, excess drug release, deformation, accelerated aging, produce a variety of serious adverse phenomenon.

Four, rubber aging phenomenon:
In accordance with the rubber product environment conditions, with the time going by, causing cracking or hardening, degradation phenomenon such as rubber physical properties, is called aging.The cause of aging, there are external factors and internal factors:
1. The external factors, external factors of aerobic, oxide, ozone, heat, light, radiation, mechanical fatigue and lack of machining process, etc.
2. Internal factors: internal factors have a rubber type, forming method, bonding degree, cooperate with the types of drugs, processing engineering of factor and so on.
To prevent aging, focuses on analysing of the correct choice and formula design, with strict production concept.So only can increase the service life of rubber products, and play their special function.

Five, the basic characteristic of the rubber products:
1. The rubber molding, after pressure pressing, the cohesion of both by elastomer, cannot be eliminated when molding from, often produce unstable contraction (rubber shrinkage rate, by analysing different difference), after a period of time required, to moderate stability.So when a rubber at the beginning of the design, formula or mould, all need to be careful calculation to cooperate, if not, the size is not stable, easy to produce products products quality is low.
2. Of hot-melt thermoset rubber elastomer, plastic belong to hot-melt cold setting.Rubber by sulfide species subject, different curing temperature range, its shape is also have quite a gap, even because of climate change, the indoor temperature and humidity.Rubber products production conditions, therefore, need do moderate adjustment at any time, if not, may produce products the quality difference.

Six, rubber joint with double-sided adhesive to distinguish:
General industrial use double-sided adhesive, acrylic plastic and rubber adhesive can be divided into two kinds big.And the two major categories, and have base material and base material can be divided into two types (adding a layer of cotton base material: rubber, strengthen the double-sided adhesive glue quantity and strength, no base material: pure gelatin, ensure transparency of the double-sided adhesive).Because for CR rubber adhesive system main body, used for rubber products, rubber vulcanization system, extremely easily with the reaction and become yellow.So the light color of rubber products, all using acrylic rubber is a base material of double-sided adhesive (with kinds of double-sided adhesive, regardless of the substrate or base material, on its own do distinguish between the thickness of the colloid.