Disposable nitrile gloves are a kind of chemical synthetic materials, by acrylonitrile and butadiene after special process treatment and formula improvement, air permeability and comfort has been close to latex gloves, and will not produce any skin allergies.
Basic Flow Chart of Thin Nitrile-butadiene Glove Soaking Material:
|Hand mould cleaning||→||Coagulant||→||Oven||→||Dip tank||→||Curling edge 1|
|Slurry tank||←||Vulcanizing box||←||Filtration and washing||←||Curling edge 2||←||Oven|
Compared with natural latex, the first difference in the production of gloves with NBR is the choice of hand models. For nitrile-butadiene gloves, the rough surface of the hand model should be selected to reduce the shrinkage of the film in the production process. Ideally, textured hand models are recommended, so that the wet film can be attached to the hand models.
Ca (NO3) 2 is usually used as a coagulant. For thin gloves, the concentration is 15-25% with 6 phrases of crystalline water. Because the film forming speed and film forming property of NBR latex are not as good as that of natural latex, the coagulant layer on the hand model should be as flat as possible. Wetting agents such as Surfynol_TG or Terric are recommended.
The leaching tank must be equipped with a good mixer, preferably a screw type, which is not easy to capture air, otherwise it will form pinholes or unstable areas. Stirring should be slow and full, so that the whole surface is moved, if the rubber sheet is formed, it means that the stirring is not enough. The movement in the leaching tank should be minimized, including the vibration of the hand model and the entry of the hand model into the leaching tank. If the hand model enters the leaching tank at a flat angle, the captured air will cause pinholes in the fingertips. The hand mold should not rotate in the leaching tank because the wet gel is weak in strength. As soon as the hand model leaves the leaching tank, it begins to rotate. The grooving temperature of the hand mold should not exceed 65 C, otherwise the gelling speed will be accelerated to produce horizontal or vertical stripes on the film.
4.Filtration and washing
The filtration process is important because it reduces the odor of gloves and prevents them from sticking. Actual washing conditions are also important. If there is a surfactant between the wet glue and the hand mold, the film will shrink. Usually the highest temperature of filtration is 50 C.
Ribbing has always been a headache for nitrile-butadiene glove producers, because the strength of the wet rubber itself is very small and vulcanization process can easily damage the curling. For better edge curling, nylon brushes should be used and the force applied on the film should be minimized. Gloves without vulcanization are easy to tear. If the equipment permits, it is better to have two edge-rolling processes, the first being placed behind the gelatinizing oven and the film is turned only once. This step can form the most basic curling. The second edge-rolling process should be placed after the filter sink. The first edge-rolling process will make the second edge-rolling process more effective.
If there is only one curling process, it is better to put it behind the gelatinizing oven.
Unlike latex gloves, nitrile-butadiene gloves must be fully vulcanized online because gloves that are not effectively vulcanized can smell, stick, cake and even wrinkle.
In order to make the final gloves wear well, chlorination is usually carried out at least on the wearing side. The remaining stickiness of the effective filtered gloves is very low, so a small amount of chlorination is enough.