Is this standard with the HD-HQ foams, or does it vary by manufacturer, and does it affect the feel of the HD foam; make it closer to an HR foam feel or no difference?
Thank you,
Coyle.
HI Alpharalpha,
Rubber is not an ingredient in the production of polyurethanes. What the industry calls “foam rubber” in polyurethane production is the result of the foaming / fizzing reaction that occurs when adding a small amount of water to the mixture of Polyol and Isocyanate mixture that are the base ingredients of polyurethane.
Polyurethanes (a form of plastic) were developed as a replacement for rubber and it uses a variety of raw ingredients in Its production such as isocyanates, polyols, stabilizers to protect the integrity of the polymer, colorant agents. (see this madehow article here)
Rubber is an elastomer as well but it’s derived either from the latex harvesting of the rubber trees, or synthetically product from petroleum byproducts. Rubber and Polyurethane are both elastomeric materials and have many similarities in terms of material properties.
Phoenix.
Ok, that makes sense. Is this how all higher density polyurethane foams are made when getting up into the 2.8lb range?
HI Alpharalpha,
High Density (HD) polyurethane foam is can be made in densities lower “than 2.8 range”. 2.8 lbs density can be both High Density (HD) and High Resiliency (HR)
Regular/Conventional, High Density (HD) and High Resiliency (HR) polyfoam have different properties (specific polyfoam chemical formulas can produce different properties) such as the variation in density, hardness, and resilience which all depend on adapting the production process and formulation of raw materials used.
To roughly classify them:
Grade 1. Regular or conventional polyfoam:
This is the lowest grade of polyfoam and weighs less than 1.5 lbs per cubic foot.
Grade 2. High Density polyfoam (HD):
This is polyfoam that has a density of 1.5 lbs per cubic foot or more although 1.8 lbs is a better guideline and best for mattresses. This is generally considered to be the bottom end of high quality polyfoam.
Grade 3. High Resiliency polyfoam (HR):
This is the highest grade of polyfoam and weighs 2.5 lbs per cubic foot or more.
To qualify as HR it must also have a support factor of 2.4 or higher.
• This support factor (compression modulus) is an important part of why a HR polyfoam has the qualities it does as it is made with a different chemical formula and has a different cell structure than the two lower grades.
Here is a good video of processes involved in Polyurethane production
Phoenix
Then are all higher density foams (2.8+/-lbs) HR or can there be a HD-HQ foam in higher density than 1.8lb?
HI Alpharalpha.
I am not very sure I understand the connection between your 2 questions so I’ll split my answer in two parts.
Short answer: No…. for an HD foam with density of 2.8 lbs/ft3 to be truly HR the compression modulus also needs to be higher than 2.4
While HD foams tend to have a higher compression modulus (also called sag factor or support factor) which is the rate that a foam gets firmer with deeper compression to qualify as an HR foam it needs to meet 2 conditions.
~ a compression modulus also higher than 2.4
~ density higher than 2.5 lbs/ft3
To expand a bit on the importance of compression modulus (the ratio between the 65% compression weight and the 25% compression weight) When a foam has a higher compression modulus … then even if it is softer than another foam with surface compression it will get firmer faster and can be more supportive than firmer foam with a lower compression modulus. Compression modulus is also a key part of the comfort of a foam as well because in combination with ILD (AKA IFD) it is part of what determines the depth of the cradle which is what redistributes weight over a larger surface area and relieves pressure.
Yes, HD foams can be in higher density than 1.8 lbs/ft3 without qualifying as an HR foam.
Phoenix
Yes, what I’m wanting is the lower compression modulus of an HD foam but in a higher density weight so it lasts longer. I prefer how the HD has more give than the HR (though I’ve used 1" 24HR over pocket coils and for that it’s great.) But for this I"m looking at 6" depth so HD36 for me has good balance between being firm enough but compressing more for pressure points. Thing is I am having a hard time finding legitimate sources of higher density HD36 as it is my first time using over 1.8lb (I had a supplier out of N. Carolina was the soy foam mix, held up good, but he’s not available so figure good time to upgrade to higher density.) Will the 2.8lb +/- HD foam be colored, like light blue, or does that vary? Can you recommend some suppliers? Thanks
HI Alpharalpha.
Yes, now it makes sense where you are coming from.
OK here are 3 options for you. The first listed is the one that matches identically what you are looking for.
• FoamByMail/ Foam Factory ~ HD36~HQ Foam from 1" to 6" in thickness which is more durable than their standard one. View its data sheet here from their site attached as well
• Foamite in Canada also has 45 grades of foam that you may want to have a look at. (see attachment)
• Foam Order EverFlex V34 from may be a good option for you.
• EconoFlex C33 is a lower grade as its density is only 1.8 lbs but the They also have a Fire-retardant Foam that you may want to check out with the density and IFD you are looking for. I am not sure what fire-retardant chemicals they use though.
https://uploads.mattressunderground.com/outside/66/FireRetardantFaoam(FoamOrder).png
Hope this helps.
Phoenix
So you’re recommending Foam Factory now? I thought they were on the no no list :silly:
I like Foamite’s soy foam (like what I used to get out of N. Carolina) but shipping from Canada (am in USA) is too expensive–but is like what I’d like to get. I trust Foamorder, have purchased from them before but HR’s high compression modulus is what I don’t want. I wanted to move up to higher density so it would last longer but is so hard to find.
Hi Alpharalpha,
It’s not really a recommendation per se as they are not a member of TMU (nor are the other ones in the list), but it is right on the mark for the foam you need. Also they are now providing the data sheets which they didn’t do before.
But yes, TMU gathered quite a collection of "no-no"s for FBM over the years. Nevertheless, who’s to say that things can’t change? Lately, TMU didn’t have complaints about them, but then we did not have any positive input either. It may be that they straightened up their act and I’d like to see to what degree. Now that they are back on the radar I’ll dig a little deeper and get in touch with them sometime soon when the time permits.
Let us know of your progress.
Phoenix