NEWS CENTER

15

2017

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07

Vinyl anticorrosive resin Vinyl 901 resin

 

Vinyl 901 resin is one of the main materials for anti-corrosion engineering of fiberglass radome. This book briefly introduces vinyl 901 resin.

English name: epoxy resin; Epoxy resin, abbreviation code EP.

Vinyl anticorrosive resin refers to organic macromolecular compounds with two or more epoxy groups in the molecule. Except for a few, their molecular weight is not high.

When using vinyl resin, the first three physical concepts to see are to describe the amount of epoxy group contained in epoxy resin from three different angles.

Epoxy value: the amount of epoxy-based substances contained in each lOOg of resin.

Percentage content of epoxy group: the mass of epoxy group contained in every lOOg of resin (g).

Epoxy equivalent: mass of epoxy resin containing 1moL ring (expressed in grams):

The three can be converted into each other by the following formula:

Epoxy content 100%

Epoxy value==(2-1)

Epoxy group molecular weight epoxy equivalent

In the formula, the molecular weight of epoxy group is 43

(1) The curing agent of vinyl anticorrosive resin, epoxy resin, is a thermoplastic linear structure and cannot be used directly. A second component must be added to the resin to conduct crosslinking curing reaction at a certain temperature to form a polymer with a network structure before it can be used. This second component is called curing agent. The curing agents used for vinyl 901 resin can be divided into three categories. One is polyamines, including aliphatic primary amine, aromatic primary amine, adduct of amine and epoxy compound, cyanoethylation product of amine, condensation reaction of phenol or formaldehyde with amine, tertiary amine, secondary amine, amide, imidazole, boron fluoride amine complex, and aminoborane. The other is acid anhydride curing agent. There are also low molecular weight resins, such as low molecular weight polyamide, phenolic resin, aniline-formaldehyde resin, melamine formaldehyde resin and urea-formaldehyde resin. This kind of curing agent can reduce the brittleness of epoxy products and improve the impact strength.

The amine curing agent of vinyl 910 resin has the following differences from the anhydride curing agent.

① Generally, the price of amine curing agent is high, while that of anhydride curing agent is relatively cheap;

② The service life of amine curing agent is short, and that of anhydride curing agent is long;

③ Amine curing agent can be cured with epoxy resin in greenhouse, and the curing speed is fast, but anhydride curing agent can cure epoxy resin at 120-200 ℃, and the curing speed is slow

④ Amine curing agents have certain toxicity, are irritating to human skin, and are easy to cause dermatitis. Acidic anhydride curing agents are highly irritating, but non-toxic, and will not cause dermatitis on the skin;

⑤ Some amine curing agents will volatilize due to heat release of resin curing, and some anhydride curing agents will be lost due to sublimation;

⑥ When amine curing agent is used, the heat release during resin curing is large, and the operation process is difficult to control. When acid anhydride curing agent is used, the heat release during resin curing is small, and the operation process is easy to control;

⑦ Generally, the thermal stability of products cured with amine curing agent is not high, while the thermal stability of products cured with anhydride curing agent is relatively high.

(2) Calculation of curing agent dosage

① The amount of primary amine curing agent can be calculated by epoxy equivalent. Each hydrogen atom in the amino group can open the ring of an epoxy group. According to this calculation, the properties of the curing system can be most suitable, and its change range is not more than 10%~20%. The dosage of primary amine is calculated as follows:

Amine equivalent

Amount of primary amine= × 100%                

Epoxy equivalent

    

Amine molecular weight x epoxy value × 100%  

=Number of active hydrogen (2-2)

Amine molecular weight

=Number of active hydrogen

For example, 618 # vinyl resin with epoxy equivalent of 200 uses triethylenetetramine (amine equivalent=146/6=24.3) as curing agent, and the amount of triethylenetetramine is as follows:

                    24.3  

Triethylenetetramine dosage=200=12.15%.

    

② Calculation of dosage of acid anhydride curing agent

The amount of acid anhydride is the proportion of resin amount (%)=(o.6~o.9) × Epoxy value × Molecular weight of anhydride

In the formula, in the range of 0.6~0.9, if the value is small, the amount of acid anhydride is small, and the mechanical properties of glass fiber reinforced plastics are high, but the heat resistance and electrical properties are poor; When the value is large, the amount of acid anhydride is large, the mechanical properties of FRP are low, and the heat resistance and electrical properties are good.

 

 

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