Blue (color) phenomenon generally does not affect the performance of products, but for the production of color and light appearance of products with high requirements (such as: rubber shoes, toys and other daily necessities), this problem is a fatal blow! Will directly result in return or rejection.
The reasons for the blue color of rubber products are mainly as follows:
1. Softener: the oil has been oxidized before being added to the compound, and the vulcanized rubber will turn blue; Adding too much rubber softening oil of macromolecular aromatic hydrocarbons is also easy to make rubber products blue.
2, carbon black: When producing carbon black, the macromolecular aromatic hydrocarbons in carbon black are not fully burned, and rubber products are easy to turn blue after adding rubber;
3. Antioxidant: excessive addition of dark antioxidant will also cause rubber products to turn blue; PEG,SA, 4010NA (EPDM is generally not added, more natural glue), the problem of such additives, there will also be a flood color problem, gummaron resin has a darker color, but also easy to color.
4, vulcanization temperature: when adding additives that are easy to blue, if the mixing temperature is too high, it is easy to make vulcanized products blue.
5, rubber mixing is not uniform: uneven dispersion is easy to cause the basic concentration of a certain additive is too high, resulting in spraying phenomenon.
6, carbon black in the paraffin oil phase is not completely dissolved, the larger the use of carbon black, the smaller the oil absorption value, the smaller the structure of the more prone to flooding phenomenon. 550 and 774 are much redder. 330 Pan blue.
7, insufficient vulcanization or vulcanization agent is less to form the spray caused by the color.
Solution:
1, the simplest to change carbon black, there are experimental conditions can be tested with different carbon black, no experimental conditions to change the brand of carbon black, glue network glue friends have proposed a test method: 30 grams of carbon black into the beaker, add water to immerse and boil, to cool the carbon black precipitation, observe whether there is oil on the surface.
2, appropriate to reduce the amount of oil, as far as possible to choose high flash point, high viscosity of the oil and softener, naphthenic oil than paraffin oil to solve the suppression of flooding better. Heavy substances such as 4010 can not be used in EPDM.
3, fillers, there is a color phenomenon, can change the proportion of fillers, try to use nano aluminate, strong powder and other materials to add 10 to 20 to solve the color is helpful;
4, vulcanization system adjustment to prevent frosting;
5, improve the processing technology, improve the dispersion;
6, for the products that have been produced, they can be boiled or baked (this method will affect the life of the products).