In order to improve the process performance, a small amount of low molecular weight fluororubber can be used in combination. For example, in a type 26 fluororubber antistatic glove with a molecular weight of 200,000, 20 to 30 parts of a type 26 fluororubber having a molecular weight of 100,000 can be obtained, thereby obtaining a compound having good mixing and molding properties, and vulcanizing.
The heat resistance of the glue has no significant effect.
For products with less shrinkage requirements, plasticizers such as dioctyl sebacate, trioctyl phosphate and high-boiling polyester can be used. When the amount is small (6 parts), the performance of the vulcanizate is not loud.
The 23 type fluororubber can be used as a plasticizer (diethyl butyl phthalate, fluoro wax (low molecular weight polychlorotrifluoroethylene) and polyisobutylene (3 to 5 parts), of which fluoro wax is the best. However, it is expensive and should be taken into account when using it. ,
It is equipped with 1-3 parts of low molecular weight polyethylene additives, which can provide good processability for calendering and extrusion of fluororubber. Because it is used in a small amount, it will not affect the physical and mechanical properties of the original antistatic glove compound.
Fluororubber formulations generally contain only raw rubber, acid absorbers, vulcanizing agents and reinforcing fillers. In some cases, a small amount of plasticizer and scorch retarder are used. Usually, other compounding agents are not used: but sometimes to improve the vulcanizate For the moldability, 0.5 part of zinc stearate can be used for demolding. Note that the dosage should not be too much, otherwise it will affect the heat resistance of the anti-static gloves.
Chloroether rubber PU coated gloves cannot be vulcanized with sulfur because they do not contain double bonds, and are generally crosslinked by the reactivity of their side chain chloromethyl groups. Compared with the copolymerization type, the latter has a slightly faster vulcanization rate and a slightly higher vulcanization degree.
The chloroether rubber can be vulcanized with a thiourea, an amine, an alkali metal sulfide, a cyanate salt, and an active hydrogen-containing compound, and a vulcanization system such as thiuram polysulfide or a triazine derivative, wherein thiourea and Triazine derivatives are more common.
There are three methods for vulcanization of thioureas using thiourea.
1 The combination of thiourea and metal compound can be used for elements of Groups 1, II, IV and VIII of the Periodic Table of the Elements. The most commonly used metals are lead and magnesium. The best effect is on oxides, and fatty acid salts, phosphates, carbonates and the like can also be used. Among the thioureas, the vulcanization rate of the accelerator NA-22 is the fastest, and the vulcanization rate of the dialkylthiourea and the trialkylthiourea is decreased. Due to the poor dispersibility of thiourea, it is difficult to obtain a vulcanizate with good performance. The aromatic thiourea is generally too slow to be vulcanized and generally cannot be used. Tetraalkylthiourea is difficult to vulcanize under normal vulcanization conditions. The most widely used is the promoter NA-22/Ph. O. The combined system, the amount of the promoter NA-22 is 1.2 parts, the Pb3 04 is 5 parts, and the sA is 1-2 parts. The vulcanizate has good heat resistance, but it is toxic, and can be changed to MgO, and the NA-22 variety has an effect on performance.
2 thiourea and sulfur or sulfur-containing compounds combined with sulfur-containing compounds with polysulfide effect, but the sulfur content of the finger sleeve is too much, but the effect is reduced, such as the effect of tetramethylthiuram disulfide is better than Dipentamethylene thiuram tetrasulfide. The combined system is characterized by flat vulcanization and is not easy to burn.
3 thiourea and metal compounds and sulfur or sulfur compounds combined with the three systems have improved vulcanization speed and vulcanization degree of the above two systems, anti-static gloves vulcanization flatness, and can be coated with general-purpose rubber PU The sulfur vulcanization system of the layer gloves is comparable. Commonly used sulfur-containing compounds are dipentamethylene thiuram tetrasulfide, tetramethylthiuram disulfide, benzothiazole disulfide or sulfenamide. Generally, the more sulfur content in the polysulfide, the better the combined effect of the three, the higher the degree of antistatic, and the faster the vulcanization rate. However, when used in combination with disulfide, the vulcanization induction period is longer and the vulcanization flatness is better. When used in combination with sulfur, the tensile strength is higher, but the compression set is larger.
