Blended latex is a mix of natural and synethic materials
A mixed latex mattress is made of a combination of synthetic and natural latex. Combo latex mattress makers claim that a combination makes the latex core more resilient. Synthetic latex is slightly cheaper and more cost effective. Pure natural latex is pricier. A mix makes the price and elemental advantage at a nice balance.
Natural latex, produced from the rubber tree, is known for its softness and elasticity. It has an inherent resistance to mold, bacteria and dust mites and is 100% biodegradable. However, it is more likely that a given sample of natural latex will have variations in product density and quality.
Synthetic latex has similar properties to natural latex, but provides slightly higher resiliency. Since synthetic latex is made with petroleum-based materials, the density and consistency can be more easily controlled in manufacturing.
Blends of natural and synthetic latex have grown in popularity due to their complimentary mixing of features. In theory, you are combining the consistency, quality and durability of synthetic latex with the elasticity of natural latex.
Another component of mixing latex is the filler. Some manufacturers may use clay or other materials in the mix, reducing cost but decreasing durability. Pure latex lacks any filler and is generally preferred by the high-end manufacturers. Both synthetic and natural latex can be considered “pure” since the term only looks to address the components added to the latex which are not either natural or synthetic latex materials.