Dunlop Latex Manufacturing
What is latex? Originally it was just natural rubber that was made from the sap of actual rubber trees. And latex is still made this way today. But during WWII, scientists also learned how to create synthetic latex. The majority of where latex comes from is from the plantation trees of Sri Lanka. Dunlap Process:
The 12 step process with Dunlap Latex
- Bulk storage Tanks
- Daily tanks
- Foaming Mixer
- Latex Filling
- Air Cooling
- Vulcanizing Chamber
- Water Cooling
- RR Dryer
- ILD Testing
A basic process in the latex production Industry is with a Mass Boiler.
- Mass Boiler: most manufacturers start the process in the mass boiler. Many companies even make their mass boiler to be sustainable, by customizing their boiler to recycle rubber tree waste. The recycled water protects the environment and works under the Zero Discharge Policy. Not all companies comply with this policy, but the ones that do will state that they do recycle.
Keep to standards: ILD Testing. What is ILD?
ILD tests the quality of compression and firmness. Compression of latex is measured through the different levels of ILD tests. ILD= Impression Load Deflection measures compression and firmness. The majority of testing the ILD is through experiments with computers. According to EC0-Latex “The foam must be 4” thick by 15”wide and by 15”long” within their testing. Keeping the same exact measurements through experiments keeps the value of the tests valid
When it comes to Dunlap Process there are 3 steps
- The liquid Latex formulation is poured into a conveyor Belt
- This liquid is heated slowly transforms into a “gel”
- This solid “gel” is removed from the conveyor belt.
There is the process of determining the hardness of the indentation technique, which is called the International Standard: ISO - The ISO is the flexible Cellular Polymeric materials.
How is ISO Measured? Through the flexible cellular materials with the Load bearing properties.
There are 5 methods to test and measure the indentation and hardness.
- Method One: testing the single indentation in the lab
- Method Two: testing the hardness of the shape, curve, and indentation in the lab
- Method Three: testing the quality of the control
- Method Four: testing the low indentation hard index, and inspection in the lab
- Method Five: determining compression deflection co-efficient and loss rate which provides info on load bearing properties and materials.
There are other forms of testing the durability of latex:
- Cornell testing
- Rollator testing
- Impact Testing
- Roller Shear Testing
- Elongation and Compression Testing
The above tests measure how well the impact of the latex will last over a lifetime.
Two Process of Latex core: Talaley and Dunlap
- The original method, called the Dunlop method, involves first whipping the latex liquid with air to make a foam, then pouring the latex liquid into a mold and heating it till it vulcanizes
- The Talalay method, which is a bit more involved. In the Talalay method, the latex foam a vacuum is placed on the mold and other processes are involved that some claim produces a foam that has a more consistent cell structure.
The foam, in either process, once made is then washed a number of times to get rid or excess soaps and proteins that can make the foam degrade early and also reduces the rubbery smell of latex. According to the Owner of The Futon Shop Suzanne’s take on Latex while buying from vendors is this: “From my experience at trade shows and in discussions with manufacturers and seasoned latex bed owners, it depended on who you talked with. Manufacturers who used the Talalay method, described their product as being less dense, having more air dispersed in the product due to the flash freeze step used in the process, and claimed that it had a more uniform cell structure. Those who used the more straightforward vulcanization technique in the Dunlop method liked the more elastic, springier feeling it creates, and had strong opinions about using all natural materials. My take: I think they are both good products, but I leaned toward the Dunlop mindset since the technique was developed using all natural latex without synthetic ingredients, and it offered a more stable product with some solid history behind it.”
Understanding certain terms: The ILD Numbers range when it comes to different manufacturers. But here is the basic rating: There is an scale for ILD rating for latex, foam, and memory foams.
Here is the average rate for Latex ILD:
- 36= Extra firm
- 32= Firm
- 28= Medium Firm
- 24= Firm
- 19= Plush
- 14 = Ultra Plush
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Click to read about the latex ingredient.
Click to read about the benefits of latex.
Click to read about how latex is harvested from rubber trees.
Click to read more about latex densities.