Latex Mattress Consumer Guide
Many terms and catchwords are used to describe latex mattresses in today's marketplace. They are interchanged, taken out of context, or misused unknowingly. How in the world can a consumer compare? As I see it the confusion results when retailers, wholesalers, and manufacturers mixing terms which cause consumers to make incorrect conclusions. I am going to approach this assuming you have already done research and encountered difficulty instead of making statements for you to take at face value. I have included a glossary of terms and a list of frequently asked terms. I hope the following information will assist you in making your buying decision by adding clarity and understanding about what latex is, how it differs from other cushioning materials and its benefits.
THERE ARE ONLY 2 TYPES OF LATEX
There are only two basic types of latex: "natural" which comes from the rubber tree and "synthetic" which is man- made from chemicals and petroleum products.
Natural Latexharvested from the sap of rubber trees grown in specific regions of the world. Natural latex is not a perfect product by the very nature of its being natural. The sap harvested is affected by soil conditions, amount of rain, and other factors that make one batch better than another. The degree of difference is not great but enough that makes it necessary for purchasers of the raw material to test for quality. It is much like buying coffee beans to arrive at different blends. Natural and synthetic rubbers have differing properties. Natural rubber is very soft and elastic; synthetic rubber gives the foam good hardness and processes better (easier to work with) in production. Compounders tend to use blends of natural & synthetic to get the best overall properties and to stabilize prices./p>
When natural rubber is tapped from a tree it is very dilute, with the rubber content being only about 30%. It has to be concentrated before use to above 61.5% solids. Of these solids, 60.0% is rubber, and the remaining 1.5% are compounds unique to natural latex (proteins, phospholipids, carbohydrates, amino acids). These unique ingredients are very important in explaining the behavior of natural latex.
Synthetic Latexman-made from chemicals and petroleum with same cell structure as natural minus the proteins found in the natural. Now, in this day and age, the mere mention of chemicals sends some people running, but let's put it into prospective. All foam is made from chemicals and petroleum products.... foam is what is used in all mattresses. The reason latex is head and shoulders above foam in quality is the degree to which natural and synthetic are blended together by two different manufacturing processes.
Before the Second World War, virtually all latex used in production was natural. During WW2 supplies of latex from the Far East were very restricted, hence the search for a synthetic alternative. Scientists tried to copy natural latex (derived from cis-polyisoprene) and largely failed: the latex produced was inferior to the real thing. Instead, they developed a latex based on a synthetic polymer that behaved in a similar way. The word "polymer" simply means a compound made up of long chains of molecules, each link in the chain being derived from simple chemicals known as 'monomers." A number of synthetic latices were developed, the most useful one being made by polymerizing styrene (a liquid) with butadiene (a gas) to give styrene-butadiene rubber, abbreviated to SBR.
THERE ARE 2 PRIMARY MANUFACTURING PROCESSES
The two main manufacturing processes used by latex manufacturers are the standard process, and the talalay process. In reality, there are a multitude of variations in the standard process by lesser known manufacturers. Someone is always trying to cut corners or substitute one step or procedure for another to save money.
STANDARD PROCESSalso called the DUNLOP PROCESS: This manufacturing process is by far the preferred process for blending natural and synthetic latex. This process produces a finished product that has a firmer less conforming feel and is a less expensive process than the "Talalay process". This process blends a combination of synthetic and natural latex liquid together, which is forced into individual molds approximately 6" x 80" x 39" and put thru specific steps to arrive at finished latex mattress cores. The standard process is a superb process but the talalay process delivers more consistancy of firmness throughout to entire core.
Talalay Processthe most advanced process for manufacturing latex mattress cores. Produces latex cores superior in comfort, durability, and in a greater range of firmnesses...from very soft to super firm.
MIXING BLENDS AND PROCESSES CREATES CONFUSION
If there are only two types of latex and basically only two methods of manufacturing then why all the confusion. As you research latex mattresses many terms and phrases are used which would lead you to believe there are many different qualities and types of latex. The problem is too many words are used incorrectly or in the wrong context. Below are examples of terms used to explain differences in latex. You might even find them listed somewhere under the headline: "There are 4 types of latex". It is easy to see how the terms can be misleading or misunderstood. As I stated earlier, there are only two types of latex, thus the terms below are more a discription of different blends, rather than "types" of latex. In addition, there can be many different blends in each of the two processes: in the standard process you could have a percentage ratio of 60% synthetic/ 40% natural or 80% synthetic/ 40% natural, or a combination somewhere in between. The same applies to the better "talalay" process.
- Pure Latex- can mean a blend of natural and synthetic and may contain as much as 80% synthetic and 20% natural.
- Natural Latex- A blend of approximately 20% synthetic, 80% natural. This can vary from manufacturer to manufacturer.
- 100% Natural Latex- 100% latex from rubber trees & manufactured using standard process. Also the "European"standard for designating a product 100% can be claimed when there is at least 80% natural. In the United States claims that a product is 100% meand just that.
- 100% Natural Talalay Latex- a rare product and up until this year only produced by Dunlopillo in England. This year Latex International began offering all natural talalay latex.
- Talalay Latex- refers to a manunfacturing process, not to a type of latex. Talalay is a blend of natural and synthetic which is not stated on most websites
BLENDED LATEX MAKES UP 87% OF ALL LATEX SOLD IN UNITED STATES
Blended latex represents the majority of all latex sold in the United States even though it could easily be assumed otherwise based on all the advertisers and retailers touting "natural latex". The charts below gives a breakdown of latex used in mattresses in the United States. It is broken down first by which process is used and second by the percent of blended and natural used in each process.
HOW LATEX IS MADE
Before the Second World War, virtually all latex used in production was natural. During WW2 supplies of latex from the Far East were very restricted, hence the search for a synthetic alternative. Scientists tried to copy natural latex (derived from cis-polyisoprene) and largely failed: the latex produced was inferior to the real thing.
Instead, they developed a latex based on a synthetic polymer that behaved in a similar way. The word 'polymer' simply means a compound made up of long chains of molecules, each link in the chain being derived from simple chemicals known as 'monomers'. A number of synthetic latices were developed, the most useful one being made by polymerising Styrene (a liquid) with Butadiene (a gas) to give Styrene-Butadiene rubber, abbreviated to SBR.
Natural and synthetic rubbers have differing properties. Natural rubber is very soft and elastic, synthetic rubber gives the foam good hardness and processes better (is easier to work with) on production. Compounders tend to use blends of natural & synthetic to get the best overall properties, and to stabilize prices.
When natural rubber is tapped from a tree it is very dilute, the rubber content being only about 30%. It has to be concentrated before use to above 61.5% solids. Of these solids 60.0% is rubber, the remaining 1.5% are compounds that are unique to natural latex (proteins, phospholipids, carbohydrates, aminoacids). These unique ingredients are very important in explaining the behavior of natural latex.
Soaps Potassium Oleate
This stabilizes the mix, i.e. it prevents it from coagulating until we are ready for it to do so, when the foam is in the mould. Soaps also assist the latex mixture to foam up when air is introduced in the foaming machine.
The latex compound is foamed up to the correct foam density, then the required amount metered into the mould. The mould is closed and the Talalay cycle begins. The mould is cooled and a vacuum is applied, which causes the foam to expand to fill the mould completely. A disposable paper gasket prevents latex entering the vacuum lines and a rubber gasket seals the mould from the outside world.
This is the key step in the foam making process. It is at this point that a phase change occurs and liquid foam becomes 'solid' foam, and the foam sets or 'gels'. In the original Dunlop Process, the foam is set by addition to the wet foam of a small amount of gelling agent (sodium silicofluoride or SSF). In the Talalay process the foam is frozen at 0°F then carbon dioxide gas (an acidic gas) is passed through the foam to lower its pH & set it.
This means that on warming up again the foam does not revert to liquid. The foam at this stage is however very weak and could not possibly be removed from the mould intact. The strength is built in during the next stage - vulcanization.
Sulphur and vulcanization
Sulphur is added to the mix during compounding. Without sulphur in the production process, the foam would resemble chewing gum and would have little resilience. The double bonds in the rubber molecule are utilized by sulphur, which forms bridges with adjacent molecules, known as cross-linking. This process gives the product its familiar properties of elasticity and resilience.
The process of heating rubber with sulphur is called vulcanization or 'curing', and was discovered by Charles Goodyear in 1839. This is a fairly slow process, even at a temperature of +240°F so certain accelerators are required in the production process to make this happen quickly. A very small addition of these reduces the time required for curing from about 25 minutes to about 8 minutes. At the end of this time the mould is cooled, opened, and the product is removed and sent to the washer.
This removes soaps, ammonia and anything else water soluble, which have served their purpose and are no longer required or desirable. If they were not removed they would contribute to discoloration, odor and could leave the product feeling tacky.
This removes all water from the block and completes the vulcanization process, thus giving the product satisfactory physical properties (compression set, tensile strength, elongation at break, pounding and indentation set). The dried products then arrive at Inspection for weighing, hardness checks and grading
Any double bonds in the rubber which are not used up by the sulphur are at risk from attack by oxygen and ozone in the atmosphere, particularly when catalyzed by the presence of UV light. This is why latex will deteriorate in sunlight. A small amount of 'antioxidant' is added to the latex during compounding. This is a substance which is preferentially oxidized (& therefore sacrificed), thus affording some protection to the rubber. Eventually however it becomes depleted and deterioration of the rubber then occurs. Latex foam must never be cleaned with solvents (dry-cleaning): this would remove any antioxidant completely, deterioration would then be very rapid.
Moulds and Heat transfer
Moulds are made from aluminum (very good heat transfer properties) and are hollow, with channels within their walls so that a heat transfer fluid can circulate through them.
Since latex foam is a very poor conductor of heat a large number of 'pins' are present to enable heat/cold to get into the heart of the foam. The resulting pinholes then play another very useful role in that they make it much easier to remove moisture during the drying process.
Frequently Asked Questions
A. This question must be answered in two parts because it infers that we may not use as good latex as the major brands. No major mattress manufacturer surpasses the quality or the quantity of the latex we use in our Select Sleep latex mattresses. We use only latex manufacturer by the talalay process as compared to latex manufactured by the standard process. In addition their mattresses are usually a combination of regular foam, blended latex using the standard process, and blended latex using the talalay process. Our latex mattresses are 100% talalay process blended latex top to bottom, edge to edge. The end result is we put more of the best latex into every mattress. The talalay process requires more advanced and complex manufacturing facilities and more steps in the process, thereby raising the product cost over the standard process. But the manufacturing process is only one aspect of comparing latex to latex. We must also take into consideration the percentage of latex that is natural and the percentage of latex that is synthetic in each latex mattress core. Ninty nine percent, ( 98%), of all talalay process latex is a blend of natural and synthetic, with the blend being 70 to 80% synthetic and 20 to 30% natural. There are many reasons why the blended is superior but here are the most important. 1.) durability-lasts longer, 2.) more consistant cell structure throughout the entire core 3.) stablizes price, 4.) diffuculty of using all natural with the superior talalay process.
The second part of the answer to this question seems rather simple. We are doing the same thing as the major manufacturers, making mattresses. The difference is we are selling direct to you the consumer. They, on the other hand, are selling to stores and sleep shops, who then must double the price to cover large overheads. It should be simple to understand they are selling to middlemen who then sell to you at higher costs. We sell direct at lower costs. The only problem with buying factory direct is finding companies who are "true factory directs" not retailers passing themselves off as such.
A. Some decisions we make are based on long term use. This is one. The term "race track" refers to standard polyfoam, not latex, being glued around the edge of the mattress which varies from manufacturer to manufacturer. Six inches is added to either side and 8" is added to the head and foot in the case of "Natures Rest". This makes the edge firmer for sitting for the user and at the same time lowers the cost of producing the mattress for the manufacturer. Poly foam can cost as much as 1/5 the cost of latex, depending on the density of the poly foam. But here's the rub. Poly foam will wear out much faster than latex and the edge of the mattress will show the wear within a few years.
A. You don't have to flip or rotate latex because it is a stronger and more durable product by the nature of its cell structure, be it synthetic or natural latex. Generally cell structure of foam does not have the tencile strength of latex and will break down much sooner. Traditional mattresses in the market use standard man made foam placed over a variety of innersprings. These foams, which vary in quality and feel, are used as comfort layers over the springs or quilted directly to the outer ticking material. As the demand grew for bigger and thicker mattresses the incidence of body impressions and breakdown increased, especially in the softer mattresses. Firm mattresses with a good spring will last longer and show less wear than softer high profile mattresses. It may be unfair to use the word breakdown because it was really normal wear and padding down. Naturally this would give the appearance that the mattress was breaking down long before it was supposed to. The solution was to rotate and flip the mattress and thus even out the wear and padding down.
A. Innerspring mattresses use foam as their cushioning material, which is made entirely from petroleum by products. The cell structure of foam does not have the tencile strength of latex and will break down much sooner and shorten the life of the mattress.
A. You will not smell the rubber through the cover in your new mattress once it is assembled. A faint odor can be detected if you smell new latex directly, but far less than regular foam, which you find in all the major brand mattresses.
A. It's not the latex you are adapting to it's the new sleeping surface whether it be latex, innerspring, memory foam, or any combination. We ask that you give your body at least two weeks to adjust to a new mattress. This takes into consideration that you have already test rested and have selected and your general firmness preference. Then it is just a matter of making minor adjustments within the confines of your home without exchanging the entire bed. That is the beauty of our Select Sleep latex mattress line.
A. To answer this question you have to know which process is being used to manufacture the latex. Blended latex manufactured by the talalay process has always been the most expensive.
A. When we use the term "talalay" we mean synthetic and natural latex blended together using the talalay process. Blended latex make up 98% of the sales of all premier latex manufacturers.
A. No I'm not. I'm saying we bare the expense of using better components in our mattresses because we are hanging our entire business around latex. They are hitting different price points in their latex mattress line with different models. To hit those price points they must cut corners by using less expensive components. Just because a component is less expensive does not mean that it is drastically inferior. It may lack specific qualities as the more expensive item but it serves its purpose in the way it is used. As an example lets take a latex mattress manufactured by a major brand and examine its components. The base layer is a 5.6" core of either natural or synthetic latex. Now this core is the base core and is there mainly for support not feel, so they are perfectly justified to use latex, other than talalay process blended latex.
To get a better understanding about latex we must draw distinctions between the two main methods of manufacturing latex.