I can certainly understand the frustration.
Regarding latex (rubber) … there are two different types of raw materials that are used to make latex foam. Each of these materials can be used to make a foam using two different foaming processes.
The raw material used to make latex foam is either natural latex which actually comes from the rubber tree and synthetic latex which is made from SBR (styrene butadiene). Many latex foams are made from a blend of the two (such as 70% SBR and 30% Natural latex or NR). Natural latex is more elastic and stretchy. SBR is more abrasion resistant and can be made more resistant to aging degradation. It is also easier to work with in terms of consistency. NR is more expensive than SBR. Blends are often used for reasons of cost, desirable combinations of certain latex qualities, and ease of working with the material. NR is often used for its natural qualities and because it is more elastic and resilient.
The two different methods used to make the foam are the Dunlop process (the original method) and the Talalay process (a newer more high tech method although it has been used for decades). The Dunlop process has two main variations and one is made in a mold and the other is made with a continuous pour method on a moving belt. Post #3 here has some videos of the different production processes.
The Dunlop method is simpler and results in a denser foam. Dunlop made in a mold is more difficult to make as soft as the Talalay process. It is also less complex and less costly to make than talalay. While it can be good quality in either a blend or all natural version … it is often preferred in an all natural version because the greater elasticity can somewhat make up for the fact that it is more difficult to make as soft as Talalay and because the lower cost of production can make up for the higher cost of using more NR latex as a raw material. It is poured in a mold or on a “belt” and then heated and cured to make the foam. It is most popular in a support layer however there are those who also prefer it in the comfort layers.
There are some newer versions of continuous pour Dunlop coming onto the market that are being made as soft as the softest Talalay which are somewhat “in between” Talalay and Dunlop although they would be closer to Dunlop in terms of how they “feel”. Dunlop is not as “lively” as Talalay because it is a denser foam with a different cell structure. Continuous pour Dunlop has a “feel” that is somewhat in between molded Dunlop and Talalay but would be more comparable to molded Dunlop than to Talalay. Continuous pour production methods result in a little less variance in terms of firmness throughout the material.
The Talalay method is more complex and results in a less dense foam. It can be made softer and more consistent than Dunlop because of the production method that uses less latex by expanding the latex in a mold using a vacuum and then freezes it so the latex particles don’t have time to settle before it is heated and cured. It is because of the lower density and the method that it can be made more consistent and softer. In spite of having less latex in the foamed core because of the Talalay production method … it has a stronger cell structure with thicker struts so this can make up for the lower amount of latex in the material in terms of durability. Blended Talalay is most often used because it can create a more durable foam … especially in the softer versions or ILD’s. Talalay that uses 100% natural rubber is also available and is more elastic than a blend but may not be as durable as the blend in softer versions (lower ILD’s). There is more about 100% natural and blended Talalay in post #2 here. It is also more difficult to work with to make a consistent firmness so the natural Talalay can be made softer than most Dunlop (except continuous pour Dunlop) but not as soft as blended Talalay. The two different versions of Talalay are very similar in feel and are lighter and more “lively” than Dunlop.
Talalay and Dunlop have often been compared to angel food cake vs pound cake. There is a little more about the differences in “feel” between Dunlop and Talalay in post #7 here.
All of these production methods make a very high quality foam that is more durable than any other types of foam materials (such as memory foam or polyfoam) and also have unique characteristics in terms of their ability to relieve pressure and provide support (get firmer with increased compression). The ability of softer latex to relieve pressure as well as memory foam and also to “hold up” the heavier parts of the body better than any other foam is part of the reason why so many people consider latex to be such a desirable material in a mattress.
There are also companies that produce organic Dunlop (which is 100% natural and has an organic certification as well). You can read more about organic Dunlop in post #6 here).
In terms of cost … Synthetic or blended Dunlop is the least expensive (less natural rubber lowers the cost of the material), Natural Dunlop and blended Talalay are roughly equivalent, and Natural Talalay and organic Dunlop are generally the most expensive. There are some variations here because of variations in methods of production and variations of NR latex used between different foam producers and other factors but in general this is roughly accurate. Which is best for each person depends on their preferences and their budget because all latex is a high quality material compared to other types of foam.
Better manufacturers or retailers like the members here are very helpful on the phone and if there is any confusion about what is on their site they do a great job in providing accurate information and any clarifications. I believe that the heading you were referring to at Sleepez is this one “100% NATURAL DUNLOP OR TALALAY BLENDED 60/40” which means that the Dunlop latex they use is 100% natural while the Talalay they use in this model is typically a 60% (SBR) and 40% (NR) blend (NOTE: this is now a 70 / 30 blend according to both Talalay latex manufacturers). The layers using these materials can be mixed and matched as they are roughly the same cost. Their 100% natural Talalay model is more expensive since it uses the most expensive latex (the latex raw material in the foam is 100% NR).
Talalay latex mostly comes from two different companies. One of these is Latex International (which is now called Talalay Global) which is US based and the other is Radium which is based in Europe. Both make very high quality Talalay products. There are many manufacturers of good quality Dunlop around the world.
Outside of normal differences between different manufacturers or retailers or differences in design … the difference in the type of latex used and the differences in various ticking/quilting used to cover the latex accounts for most of the price differences between different lines (wool quilting for example is significantly more expensive than just a material without a wool quilting).
So to recap … Synthetic or blended Dunlop is usually the lowest cost version of latex (including some of the newer continuous pour synthetic or synthetic blend Dunlop latex materials which are also promising in terms of durability) but higher percentages of synthetic rubber in a blend will generally result in a lighter (less dense) and less elastic and resilient material that is a little less “supportive” (it has a lower compression modulus which is the rate that a material becomes firmer as you compress it more deeply) but they can make a good choice if budget considerations are the most important factor and all latex is a high quality and durable material compared to other types of foam. Continuous pour Dunlop can be found in softer versions than most of the molded Dunlop you will find. 100% NR Dunlop or blended Talalay (70% SBR / 30% SBR) are the next up in price and are the most popular choices for overall performance and “value” while 100% NR Talalay or organic Dunlop is the most expensive. 100% natural Talalay latex is most popular with those who want talalay latex in its most natural version or in its most elastic version in spite of the fact that it may be less durable in softer ILD’s in a comfort layer. Organic Dunlop is most popular with those where an organic certification is important for personal reasons regardless of whether there is any difference in the actual feel or performance between organic Dunlop and 100% natural Dunlop which is basically the same material without an organic certification.
In terms of safety … all the latex you are likely to encounter (whether it’s Dunlop or Talalay and made with natural rubber, synthetic rubber, or a blend of both) will have been tested for harmful substances or VOC’s by either Oeko-Tex or Eco-Institute and certified as being “safe” so safety wouldn’t be an issue for most people regarding any type or blend of latex (see post #2 here for more about certifications)
While there are many websites that try to portray Dunlop as being more durable than Talalay or the other way around … I treat them as equivalents and as a preference choice rather than a better/worse choice in terms of durability and in a suitable design and firmness level both have a very long history that shows that in some cases they can last for decades (see the video here for an example)
The most “popular” choices in terms of a combination of foam characteristics that most people seem to prefer in terms of performance and price (value) is Talalay in the comfort layers and either NR Dunlop or Talalay in the support layers although any type of latex can be used in any layer and some people (including my own daughter who prefers Dunlop in the comfort layers) have much different preferences than others so I would make sure you have tested both to see which one you prefer. Your own experience and preferences are always the most important factor in choosing between them. In some cases (depending on the many factors that play a role in durability) latex mattresses with firmer layers can last over 20 years.
Hope this helps to “decode” the different types of latex.