In life, many people must have seen that rubber products will appear white after a period of time. For example, when the humidity is large, the paint will become white easily.

Spray frost

Rubber is divided into vulcanized rubber (hereinafter referred to as rubber compound) and vulcanized rubber (hereinafter referred to as products). Rubber sprays contain spray and frost on the surface of products. Bloom is the appearance of a liquid or solid mixture from the interior of the rubber to the surface of the rubber [1]. It can be seen that the internal mixture of rubber is separated and the spray frost is formed. The method of rubber spray is divided into three types. That is, spray, spray wax, and spray (also called exudation).

The powder is a curing agent, accelerator, activator, antioxidant and filler in the rubber powder mixture with separate appearance, form a layer of powder.

Spray wax is white wax, ceresin wax and other rubber isolated in appearance, and form a layer of wax.

The injection is softening agent, tackifier, lubricants, plasticizers and other additives in the separation of liquid rubber appearance, form a layer of oil. In practice, the appearance of a rubber frosting is sometimes presented in one way, sometimes in two or three ways.

(1) the formulation is not properly planned:

Full discharge: common in sulfur, accelerator, activator, antioxidant from relocation: common in processing aids, relocation. Antistatic agent generation and ejection: commonly used in accelerator system of sulphur vulcanization and repercussion with regenerated products: common organic peroxide vulcanization system, low molecular substances, excessive stress emission: common inorganic filler: calcium carbonate.

(2) technical operation is inappropriate:

Unevenly mixed mixing is a slack, partly beyond the plumpness

High temperature, overdose of the mixture

Imprecision of weighing (multi name, less name, leak name, wrong name)

High curing temperature and high polymer degradation make spray frost

The vulcanization temperature is too low, and the incomplete sulphur attack occurs. The sulfuration time is not good. It constitutes improper operation of the ejection agent or washing water, which forms the white appearance of the rubber appearance.

(3) the quality of raw materials affected by raw material origin is not the same, is not the same as the law, technology is not the same, not the same batch of raw materials are very different, which were: Technology of polymerization temperature, catalyst composition, different monomers, the solubility is not the same. Seizure changes such as purity, moisture, ash, pH value, physical properties and so on

(4) poor storage conditions: temperature with solubility in the rubber agent is usually followed by the temperature and time of lifting (pressure: pressure, humidity) by the rubber storage when the humidity of the surrounding air and time solubility of complexing agent is also affected, usually have little effect. However, if the pressure, agent would constitute a nucleus with the compression part of the rubber, rubber composition for sub appearance, blooming; if the air humidity is too large, the rubber polarity with the agent of rubber (nonpolar) effect weakened, compound solubility is reduced, then the frost spray; the storage time is longer, the appearance of rubber spray frost more significant, because the air temperature and humidity in the storage environment with the season change is not the same, but not as large, easy to form solubility complexing agent change, then the spray frost.

(5) rubber aging

Most of the aging of rubber mesh structure balanced vulcanizates intact attack damage, and damaged the rubber system with various agents and rubber molecules as well as the relation between the chemical complexing agent or physical, with lower solubility agent in rubber in the system. As a result, those parts that are in full condition will be separated from the rubber and form a spray frost.