Latex reclaimed rubber has characteristics such as high tensile strength, good elastic feel, high elongation at break, and ease of processing. It can be used together with natural rubber to produce ordinary air hoses suitable for normal temperature and low pressure, effectively reducing raw material costs. In actual production, latex reclaimed rubber is not simply a substitute for natural rubber. If the ratio of natural rubber to reclaimed rubber, the reinforcement system, the softening system, or the mixing and vulcanization process are not properly coordinated in the air hose formula, issues such as insufficient hose strength, reduced aging resistance, and poor dimensional stability are likely to occur.
1. Why latex reclaimed rubber can replace natural rubber in air hoses
Latex reclaimed rubber is made from waste natural rubber, waste latex, and their products. It retains the high elasticity and high elongation of natural rubber and is compatible with natural and synthetic rubber. It has excellent plasticity and flow properties and can meet the basic performance requirements and processing needs of air hoses. Reasonable use of latex reclaimed rubber in ordinary air hoses not only reduces raw material costs but also facilitates mixing, extrusion, and molding when used with natural rubber, improving the dimensional stability of the finished hoses.
2. Tips for choosing latex reclaimed rubber for air hoses
Air hoses vary in working pressure, diameter, wall thickness, and usage environment, so the requirements for rubber properties differ. It is recommended to choose latex reclaimed rubber according to the hose's specific needs, focusing on tensile strength, elongation at break, Mooney viscosity, ash content, impurity content, and quality stability. For thin-walled hoses, it is better to choose 80-mesh superfine filtered latex reclaimed rubber for better airtightness. Light-colored hoses can use white latex reclaimed rubber for easier coloring.
3. Mixing ratio of latex reclaimed rubber in air hoses
For ordinary industrial air hoses, air pump connecting hoses, and similar products, latex reclaimed rubber can be used together with natural rubber at a ratio of 30%-70%. If the hose is under high pressure for a long time or needs frequent bending, the proportion of natural rubber should be increased appropriately. To reduce costs, do not add too much reclaimed rubber; keep its proportion at 10%-30%. Low-stress hoses can use latex reclaimed rubber alone, preferably with a rubber content ≥80% and tensile strength ≥13MPa.
4. Balancing reinforcement and softening when using latex reclaimed rubber in air hoses
When producing air hoses mainly from natural rubber, using latex reclaimed rubber to save costs, the formula can adjust the reclaimed rubber amount according to product requirements and use fillers like carbon black, white carbon black, or calcium carbonate to adjust hardness, strength, and processing performance.
As the proportion of latex reclaimed rubber increases, the raw rubber's elasticity and reinforcing ability usually change, so the original natural rubber formula cannot be followed mechanically. Too little carbon black may result in insufficient tensile strength of the vulcanized rubber; too much filler can make the rubber hard and reduce flex resistance. Air hoses need some flexibility, but excessive oils can weaken the material's physical properties, affecting airtightness and pressure resistance.
When balancing reinforcement and softening, focus on vulcanized rubber tensile strength, elongation at break, hardness, and flex resistance, rather than just ease of processing.
5. Adjusting mixing and extrusion processes with latex reclaimed rubber in air hoses
After adding reclaimed latex to air hoses, the rubber compound usually becomes easier to plasticize and mix, but that doesn’t mean you can just shorten the mixing time. If the powder isn’t dispersed thoroughly or the softener is added too early, it can cause local greasiness in the rubber or uneven filler distribution, which will eventually affect the surface quality and physical properties of the hose. When mixing, it’s important to control the compound temperature to avoid the curing system reacting too early due to excessive heat.
For air hose extrusion, you need to consider the compound temperature, die pressure, and die opening size. When the proportion of reclaimed latex changes, the compound flow and die swell behavior also change, so you can’t just use the original extrusion parameters. If the hose shows issues like fluctuating outer diameter, rough surface, or uneven wall thickness, you need to check things step by step, including compound Mooney viscosity, filler dispersion, extrusion temperature, and screw speed.
The key to using latex reclaimed rubber in air hoses is 'using the right proportion for the right product.' Ordinary low-pressure air hoses can reduce costs by reasonably increasing the reclaimed rubber content. For hoses requiring high strength and fatigue resistance, focus on strength and dynamic performance, controlling the reclaimed rubber amount. Air hose producers can initially do small-scale trial formulations, comparing Mooney viscosity, vulcanization characteristics, hardness, tensile strength, elongation at break, and finished hose pressure resistance under different reclaimed rubber contents, reducing costs while maintaining performance.
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