Natural latex recycled rubber is made of waste natural rubber, waste latex and its products such as waste latex gloves and finger covers, and is made by crushing, desulfurization, refining and other processes, and has the basic performance characteristics of natural rubber, which can be used alone or in combination with natural rubber to produce rubber products, effectively reducing the cost of raw materials. When using white latex recycled rubber to produce colored rubber products, it is crucial to improve the color resistance of the rubber products.
1. Choose environmentally friendly non-migrating latex recycled glue
The quality of latex recycled rubber plays a decisive role in the color change resistance of colored rubber products. When using latex recycled rubber to produce colored rubber products, it is important to choose latex recycled rubber E5LYY36 with sufficient desulfurization and low impurity content. The effective rubber hydrocarbon content of Hongyun white pure latex recycled rubber reaches more than 75%, with high strength, small specific gravity, good feel elasticity, light color, easy color matching, not easy to change color, environmental protection and odorlessness, etc., which can be used alone or in combination with natural rubber to produce colored rubber products, effectively reducing the cost of raw materials.
2. Reasonable design of colored natural latex recycled rubber product formula
(1) Reasonable selection of antioxidants
When using latex recycled rubber to produce colored rubber products, adding an appropriate amount of antioxidants can effectively inhibit the oxidation reaction of rubber molecules and slow down the discoloration phenomenon caused by oxidation. Adding an appropriate amount of ultraviolet absorbers can effectively absorb ultraviolet rays and reduce the damage of ultraviolet rays to rubber molecules and pigments, such as benzophenones, benzotriazoles, etc.
(2) Reasonable selection of rubber oil
In the production of colored natural latex recycled rubber products, aromatic oils are more likely to change color than paraffin oil and naphthenic oil, so aromatic oils should be avoided.
(3) Rational design of vulcanization system
Adopt a low-sulfur and high-sulfur pro-sulfurization system to reduce the content of free sulfur and reduce the yellowing of "sulfur spray"; The use of retardation accelerators and appropriate extension of the scorching time can prevent surface microcracks and discoloration caused by early cross-linking of high-temperature processing. The compound with peroxide vulcanization has better color resistance than the compound with sulfur vulcanization.
(4) Reasonable selection of color pigments
Colored natural recycled rubber products give priority to varieties with excellent lightfastness, heat resistance, and migration resistance, such as quinacridone pigments in organic pigments, which maintain good color stability in the rubber system. A small amount of inorganic pigment titanium dioxide is added to help improve the color resistance of the product.
3. Improve the processing technology of colored latex recycled rubber products
When using natural latex recycled rubber as the main raw material to produce colored rubber products, the processing technology has a certain impact on the color resistance of the product.
(1) When mixing latex recycled rubber, it is necessary to reasonably control the mixing temperature, mixing time, etc., and the initial temperature of mixing should be controlled at ≤60°C to avoid pigments softening and agglomeration in advance at high temperatures; After mixing the pigment with the recycled glue evenly, add additives such as anti-aging agents. Uneven dispersion of compounds can easily lead to high local pigment concentrations or uneven distribution of additives in recycled rubber materials, accelerating the discoloration of color latex recycled rubber products.
(2) During the vulcanization process of natural latex recycled rubber, the vulcanization temperature and time need to be strictly controlled to avoid oversulfur or undersulfur. Persulfur may over-cross-link the rubber molecular chain, resulting in brittleness and discoloration of the product; Lack of sulfur will cause the rubber to be insufficiently cross-linked, reducing physical properties and color discoloration resistance.
In actual production, latex recycled rubber can be used alone or in combination with natural rubber to produce colored rubber soles, rubber plates, tapes, hoses, rubber toys and other colored rubber products; Choosing the appropriate latex recycled rubber, reasonably designing the rubber product formula, and appropriately adjusting the production process can effectively improve the color discoloration resistance of rubber products.
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