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normal Latex Durability: Dunlop vs. Talalay

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19 Sep 2011 23:30 - 19 Sep 2011 23:34 #1 by SonicExplorer

Hello,

Hoping maybe the forum can shed some light on the subject in question. I am growing entirely frustrated with the research I've done regarding 100% natural Talalay and Dunlop latex with regards to durability. There are people and sites that swear one is better than the other and I've seen inconsistent data pointing both directions.

To be clear, the question being raised is in the context of durability only. Specifically two aspects: The ability for latext to retain most of it's original size and resistance. Or said another way, which type of latex will better retain it's height (reducing the likelyhood of impressions) and which will better retain it's original "feel" (resistance) over time?

Thanks,

Sonic

Last Edit: 19 Sep 2011 23:34 by SonicExplorer.

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20 Sep 2011 02:37 - 14 Dec 2014 23:29 #2 by Phoenix

Hi Sonic,

This is an ongoing discussion all over the web which has been going on for many years ... much of it based more on what people like rather than on fact. The actual durability of any latex will also depend a great deal more on how it is used and how it is protected as it will break down with exposure to ozone and ultraviolet and certain solvents and some of the other substances that are listed here .

IMO ... neither can accurately be called better than another as it entirely depends on the use they are being put to. In certain applications ... Dunlop is clearly superior when a higher compression modulus is desirable. In other applications ... Talalay is superior when softer more consistent foam is desired. Some of the newer continuous pour Dunlop materials are somewhat in between the two in that they are available in softer ILD's and can be more consistent in terms of ILD variances across the surface and from top to bottom than molded Dunlop (see post #6 here ).

I realize though that you are asking strictly about durability so I will deal with that ... starting with a comparison with NR vs SBR.

In general terms ... denser natural latex is more durable in instances where stretching is required as it is more stretchy (elastic) while SBR is less elastic. NR has a higher tear strength. NR has slightly less abrasion resistance and weathering degradation or thermal oxidative degradation than SBR (according to most research) which is why SBR is often used in tire compounds. 100% NR Talalay is less dense than 100% NR Dunlop but has a more even internal cell structure which is considered by many to be less prone to internal breakdown (although there is little research here ... it makes sense).

Overall (balancing all the competing factors that I'm aware of from a great deal of research and many conversations with manufacturers and producers) ... I would rate 100% NR Talalay, blended Talalay, and 100% NR Dunlop about equal in the higher ILD's with a slight edge to Dunlop and blended Talalay as the ILD goes down ... but how long each lasts would depend more on the use it was put to than on which type of latex in most cases. The difference in real life is likely to be rather insignificant in the higher ILDs.

As ILD goes down ... particularly into the low twenties and teens ... 100% NR talalay is likely to be less durable than blended Talalay or NR Dunlop because internal shear forces in the 100% NR in the lower density Talalay may well cause its greater elasticity to work against it and "stretch" the less dense lower ILD NR talalay to the point of "breaking" the cell walls more often. So in terms of the lower ILD's both Dunlop and blended talalay would likely be more durable than 100% NR talalay.

Latex International introduced 100% NR talalay not because it was a better material in terms of performance but because they wanted to have a product that was more desirable to those who wanted materials that were more natural regardless of durability. They know that it is likely to be less durable ... especially in the lower ILD's ... than the blend (or Dunlop) which is why their guarantee is shorter on the NR than on the blend. They themselves will readily acknowledge this.

So to recap ... blended Talalay, NR Talalay, and NR Dunlop are likely to be about equal in the higher ILDs. In practical terms this means that used in a mattress core they are likely to be close to equal.

As the densities go down ... 100% NR talalay may start to fall behind the other two ... assuming the materials being compared are of the same ILD. In practical terms this means that in a comfort layer the lower the ILD the durability advantage may go to the NR Dunlop and blended Talalay ... even though Dunlop is not usually seen in ILD's that are as soft as Talalay so an "apples to apples" comparison cannot really be made for the lowest ILD NR Talalay.

There are also some types of Dunlop being made now that use a continuous pour process from either Latexco or Mountaintop in various blends (including synthetic Dunlop from Mountaintop) that are comparable to Talalay in terms of ILD and consistency and are also proving to be very durable materials. Blended Talalay can be made in lower ILD's than the NR Talalay and is generally considered to be more durable in the lower ILD's than NR talalay. This would be particularly true with Latex International Talalay. Radium has told me they use a different "curing paste" in their lower ILD NR Talalay products which creates a smaller cell structure and which they claim and their testing indicates is just as durable as the blend in lower ILD's.

While there is no way to "quantify" all this because there are so many variables involved and there is no specific comparative information that is publicly available and because the different strengths and weaknesses of each material will have as much to do with durability in a particular application as the material itself (given the exact same use and the exact same ILD) .. based on the experiences of manufacturers that have been working with latex for decades and on the information that is available ... this is likely to be as accurate as it's possible to be.

Since all latex is more durable than most other materials and other types of foam ... I would make choices based on which had the more desirable qualities in the application it was being used for, on budget considerations, or on individual criteria and preferences rather than a "better worse" comparison.

There is also more about the differences in how Dunlop and Talalay "feel" and respond in post #7 here .

Phoenix


Researching for a mattress?... Be sure to read this post first.
Last Edit: 14 Dec 2014 23:29 by Phoenix.

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19 Jul 2013 15:16 #3 by dparsons01

Found these while I was out investigating "which latex is better?"

A bed manufacturer found some latex that had been stored folded and compressed for 4/5 years and opened it up. The Talalay bounced right back. The Dunlop did not. There is a movie of this on the page.
www.flobeds.com/information/latex/talalay-vs-dunlop.htm

This site says Talalay has a higher tensile strength, will elongate more, and is more consistent.
www.seattlemattress.net/seattlemattressfaqlatex.html

From an engineer's perspective, those are better properties.

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19 Jul 2013 22:16 - 19 Jul 2013 22:20 #4 by Phoenix

Hi dparsons01,

A bed manufacturer found some latex that had been stored folded and compressed for 4/5 years and opened it up. The Talalay bounced right back. The Dunlop did not. There is a movie of this on the page.
www.flobeds.com/information/latex/talalay-vs-dunlop.htm


This is somewhat misleading because latex that has been compressed for a long period of time (especially Dunlop) doesn't act or age the same way as latex that is uncompressed. You can see a video here of an example of Dunlop latex that was in use for almost 50 years. There are many examples of both blended talalay (they didn't make 100% natural at the time) and 100% natural Dunlop mattresses that originated from the 60's and 70's that were in regular use for decades. I see many articles all over the internet that attempt to portray one type of latex as being "better" than another and all of them miss the point that they are simply different and each has its strengths and weaknesses. I've seen comparisons for example that try to say that Talalay is several times as durable as Dunlop (or the other way around) and in fact if this was true then the latex in question would need to last over a century to make the claim accurate which of course isn't the case.

This site says Talalay has a higher tensile strength, will elongate more, and is more consistent.
www.seattlemattress.net/seattlemattressfaqlatex.html


It would be interesting to see the specifics that validate their claim including the type, ILD, and manufacturer of the latex that they are comparing. In most cases these are simply claims that aren't based on "apples to apples" comparisons. These types of comparisons would depend on the specifics of the two types of latex being compared. For example the Latex International site here has a comparison between talalay and dunlop of the same density but this would be comparing two foams with very different ILD's because in the same ILD Dunlop is denser than Talalay. For Talalay to be as dense as Dunlop it would need to have a much higher ILD which of course would make it more durable (firmness is a durability factor) and would increase the thickness of the cell walls. The same document also says that "impact loss" (that doesn't say if it measures height or ILD loss) is only 6% vs 16% with Dunlop and yet if you look at their Q&A #4 here they list "Asian 100% natural latex" (without saying which type of Asian latex because there are many manufacturers) is the "worst" at 12.5%. If you look at the durability specs at the Latexco site here you will see ILD and height loss of Dunlop that is much less than what Latex International claims and less than their Talatech latex. There is no consistent standard of comparisons in most areas.

While these types of comparisons often have some truth in them (whether they claim that Talalay is 'better" than Dunlop or the other way around) ... they are not the complete picture. Talalay will tend to be more consistent for example (particularly blended Talalay) but there are also newer types of continuous process Dunlop being made by Mountaintop and by Latexco that are very consistent in ILD. Natural latex is also more elastic and has a higher tensile and tear strength than synthetic latex so the blend would also play a role as much as the process. Natural talalay is also not as consistent as blended Talalay which is why Latex International doesn't rate them to specific ILD's but to a range. These types of generalizations are often driven by what the specific site that makes the claim is selling.

I have yet to see these types of claims backed up with specific information that includes detailed specifics, are apples to apples comparisons, and have been validated in real life experience over the course of years. I think it's fair to say that Talalay has a more open cell structure which makes it more breathable than Dunlop at the same ILD and is more "responsive" or "lively" and that Dunlop is more dense and has a higher compression modulus, higher resilience, and lower hysteresis but beyond that the comparisons become more suspect and would depend on the specifics of what you are comparing.

Phoenix


Researching for a mattress?... Be sure to read this post first.
Last Edit: 19 Jul 2013 22:20 by Phoenix.

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21 Jul 2013 13:02 #5 by dparsons01

Thanks for the response.

Phoenix wrote: You can see a video here of an example of Dunlop latex that was in use for almost 50 years.


Interesting. Nice to see that. Where does it say its Dunlop?

Phoenix wrote: It would be interesting to see the specifics that validate their claim including the type, ILD, and manufacturer of the latex that they are comparing. In most cases these are simply claims that aren't based on "apples to apples" comparisons. These types of comparisons would depend on the specifics of the two types of latex being compared. For example the Latex International site here has a comparison between talalay and dunlop of the same density but this would be comparing two foams with very different ILD's because in the same ILD Dunlop is denser than Talalay. For Talalay to be as dense as Dunlop it would need to have a much higher ILD which of course would make it more durable (firmness is a durability factor) and would increase the thickness of the cell walls. The same document also says that "impact loss" (that doesn't say if it measures height or ILD loss) is only 6% vs 16% with Dunlop and yet if you look at their Q&A #4 here they list "Asian 100% natural latex" (without saying which type of Asian latex because there are many manufacturers) is the "worst" at 12.5%. If you look at the durability specs at the Latexco site here you will see ILD and height loss of Dunlop that is much less than what Latex International claims and less than their Talatech latex. There is no consistent standard of comparisons in most areas.


They say "impact Loss for Talalay Latex Rubber is on average 6% for all ILD’s. Impact Loss for a Dunlop latex Rubber is generally 16% or higher." (emphasis mine) Also, since ILD measure force for a 25% deflection, that should be what is measured - the reduction in strength.

Yes, their use of "Asian" and "European" latex does limit the ability to verify the comparison. It also may keep them out of liability problems. I'm not suspicious that they are purposely making Dunlop look bad as they could choose to make their own Dunlop as well.

On elongation, Latex Intl says "Talalay Latex Rubber has much better elongation than Dunlop latex Rubber. The higher elongation means the latex Rubber can stretch farther and absorb more energy before breakage occurs. The property is not only important to durability but also to material handling. The source of Talalay Latex Rubber’s superior elongation lies in the thicker cell walls and quality starting materials."

The better scores on impact and elongation tests do correspond to the behavior observed on the 5-year old foam unpacking video. Yes, it isn't exactly normal conditions other than that is the way the latex foam is shipped and is part of what it endures. The video does give a visual of how the materials behave. The Talalay recovered its shape better.

In the paper Latex Intl. also presents testing the airflow through the latex, getting 2x the flow with Talalay using the same pressure, due to the larger porosity. This translates to breathability and comfort.

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21 Jul 2013 14:23 - 21 Jul 2013 14:29 #6 by Phoenix

Hi dparsons01,

Interesting. Nice to see that. Where does it say its Dunlop?


You can see the title here and I've also talked to Ken who is one of the members here.

They say "impact Loss for Talalay Latex Rubber is on average 6% for all ILD’s. Impact Loss for a Dunlop latex Rubber is generally 16% or higher." (emphasis mine) Also, since ILD measure force for a 25% deflection, that should be what is measured - the reduction in strength.


They don't define what impact loss means (it's used to test height loss or ILD loss) although either way this doesn't match many years of experience in "real life" where softer latex ILD's certainly will soften and break down faster than higher ILD's (which is why some manufacturers avoid any Talalay ILD lower than 19 or so). It's always easy to take selective specs and then compare it to an unspecified competitor or material to make things look better than they are. Not all ILD measurements are at 25% (especially with latex) and ILD loss also depends on the depth of measurement. It's practical effect also depends on other specs as well including compression modulus. These types of increasingly granular and non specific comparisons in the absence of all the other connected information that is just as important becomes less and less meaningful and useful.

The undue emphasis on which is the "better" latex (usually based on limited and carefully selected or in some cases misleading information) is fruitless IMO because there are too many definitions of "better" which depend on the subjective experience and preferences of each person and on the type of comparison and the specifics of what is being compared. In most cases these types of comparisons lose sight of the forest for the trees.

Phoenix


Researching for a mattress?... Be sure to read this post first.
Last Edit: 21 Jul 2013 14:29 by Phoenix.

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05 Aug 2013 13:16 #7 by djag67

Phoenix wrote: softer latex ILD's certainly will soften and break down faster than higher ILD's (which is why some manufacturers avoid any Talalay ILD lower than 19 or so). Phoenix


Is one example of this PLB (looking at their mattress specs from your previous post ). Is this why they separate the 14-15 ILD Talalays as mattress toppers? So the toppers can be replaced as necessary without having to refurbish the entire mattress?

I was debating getting a custom mattress and thought about having 15 ILD Talalay as the final comfort layer, but would I be better off just leaving that out of the mattress, and getting it as a separate topper?

Thanks

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05 Aug 2013 13:26 #8 by djag67

Also, one other question (apologies if there is a better thread for this elsewhere):

What's the difference between Talalay Classic (Talatech) and Talalay GL ( www.latexfoam.com/latex-material/components )

Thanks again

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05 Aug 2013 15:54 - 05 Aug 2013 15:55 #9 by Phoenix

Hi djag67,

Is one example of this PLB (looking at their mattress specs from your previous post). Is this why they separate the 14-15 ILD Talalays as mattress toppers? So the toppers can be replaced as necessary without having to refurbish the entire mattress?


I don't know the thinking process behind their design choices or if this was their primary consideration but it's more likely that it was intended as a design choice that would give people options to customize their mattresses (their 2" and 3" topper can be used on top of any of their mattresses). The side effect of this though would certainly be that the topper could be replaced without having to replace the entire mattress and I would think that this was part of their thinking as well although they (and their retailers) are not as likely to mention that ILD's in this softness range would be less durable.

I was debating getting a custom mattress and thought about having 15 ILD Talalay as the final comfort layer, but would I be better off just leaving that out of the mattress, and getting it as a separate topper?


If I was using latex this soft I would either tend to add it as a topper or as a separate layer inside a zip mattress cover. Either way it could be replaced independently without changing the entire mattress. I wouldn't tend to use it inside a finished mattress that would require cutting open the cover to replace a layer and then having to resew the cover or buy a new one.

Of course for someone that was very light this softness level would be less risky in terms of durability.

What's the difference between Talalay Classic (Talatech) and Talalay GL ( www.latexfoam.com/latex-material/components )


talalay GL is basically the same as Talatech (blended talalay latex) except it has gel capsules blended into it that contain a phase change gel which changes phase from solid to liquid when temperatures reach certain levels. Phase change gels have the ability to either absorb heat or release heat (depending the direction of the phase change) so it can assist in maintaining temperatures within a certain range.

It comes in both a fast response and slow response version. The fast response is similar to Talatech while the slow response uses a different formula for the synthetic latex that gives it some of the slow response "feel" of memory foam.

The Talalay GL fast response used to be called Celsion (and still is in some places) and the slow response latex replaced a previous version that didn't have the gel called NuForm.

Pure Latex Bliss (which is owned by Latex International) calls the same material "Active Fusion" fast response and slow response.

Phoenix


Researching for a mattress?... Be sure to read this post first.
Last Edit: 05 Aug 2013 15:55 by Phoenix.

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22 Sep 2013 07:32 #10 by Pspa123

Informative thread. I am looking to add a 2 inch layer of a "medium" latex in between my current layers of firm Dunlop 5.5 inches and soft natural talalay 3 inches. My plan is to put the medium inside the mattress cover, and then use the soft as a "topper." For this application, would blended talalay or natural be better? There is of course a cost savings with the blended but not huge. Thanks.

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