Right now, the time is 9:05 AM and I really plan on researching weighted blanket materials all day. As I was copying my research notes into Zotero and organizing my grid in Microsoft Word, I thought, why not just record down all my thoughts as I’m doing the research to help you guys?
In my prior post on weighted filler material selection between plastic and glass, I was only considering one part of the weighted blanket equation. Another primary concern is the fabric used for our duvet cover. The primary goal of weighted blanket materials research is to find a good combination for a cool summer blanket.
Our process of describing the calculated rationale behind the truHugs weighted blanket material selection process for the cover can lead to discussions about product design. It is our hope that the “compare and contrast” storyline writing style, using bamboo as the featured example, will make the fundamental science a little easier to swallow. Then later, we can easily elaborate on why our inner duvet was chosen to be cotton because at that point in time our readership is already educated in textile material properties in general.
Most popular weighted blanket materials for covers
We were initially motivated to start truHugs because the weighted blankets we had before had weighted pockets that were too big, which would result in the beads shifting around. In our first market analysis, we saw that a lot of people were selling weighted blankets made out of…
Cotton (Most popular and YES! It’s natural)
Cotton has been used for thousands of years and is regarded as a safe, natural, and functional textile (as long as it is grown organically). Cotton’s rates of water absorption or regain relative to humidity are bettered only by wool, silk, and certain types of bamboo fabrics. This means that while sleeping, the cotton is better equipped to wick away sweat.
Man-made plastic fibers, including all forms of polyester and polypropylene.
Examples may include: a) Minky, b) Fleece, c) Plush, and d) Acrylic. Fiber structures may vary. New forms of polyester that have arrived since its popular use in the 1950s that have lower densities are called ‘micro’ in the modern day. Examples of polyester plastic fabrics given different names are “micro-fiber, micro-plush, and microfleece.” Then you have some natural/synthetic blends like Chenille, which often blend polyester with other synthetic and natural fibers.
Despite market popularity, we had our own goals:
- Minimize harm to the environment during manufacturing
- Improve on flaws that have limited functionality for weighted blankets including a) making sure the skin is in contact with a material that is smooth, non-bumpy, and soft; b) improving thermal regulation; c) improving duvet durability.
- Make sure the quality level is something you guys are willing to pay for
Battle of weighted blanket fabrics that ‘hug’ your skin: what’s hot and what’s not?
In order to understand some of how we got to reporting the results we did the way we did below, we recommend you read our quick (less than five minutes read time) guide on how to effectively conduct your own material science ‘quick tips’ R&D of any fabrics you are considering.
The materials used today within different weighted blanket products all have an impact on how hot or cold your blanket will turn out to be. Depending on where you live, you may have different thermal regulation requirements. This may impact which weighted blanket you purchase due to the materials they use.
If you are currently confused about how to determine how your cover will affect you, please visit our comparative material analysis post between truHugs cover material, bamboo lyocell and the other most commonly used weighted blanket cover materials.
Please take our material analysis with a grain of salt
Even though raw material fiber characteristics affect fabric characteristics, fabrics can be manufactured in different ways that result in different fabric properties
Different fabric samples confound the analysis
Our analysis of materials used for weighted blankets that touch the skin references various studies used for different fabrics both synthetic and non-synthetic. These studies often differ in how the yarn fibers were weaved into fabrics, creating different material properties that result in different end-user experience. Yarns can have an effect on how durable, breathable, and soft the resulting fabric can be. Different fabrics – Both woven and raw– exist for different purposes and how the fabrics are applied (whether for clothing or for blankets).
Raw fiber property effects and global textile standards help control for differing samples…somewhat
Differing fabric samples of the same material and different types of materials have traditional conventional properties that are innate to their chemical molecular composition, which affects a material’s fiber properties at a microscopic level such as fiber density and porosity, which then affects minimal fabric density to meet daily use durability requirements by consumers.
In addition, many of the material science studies measure fabric properties based on global standards. These global standards vary per fabric to maintain a minimal level of quality (durability, convenience) for textile production per application. Over time, many of the mass-produced fabric variations within each material type (lyocell, viscose, cotton, and polyester) have been ‘spec’ optimized for end-user experience over their history of use within the weighted blanket market today.
Our commitment to objective reporting
In order to control (as much as we can, pure objectivity is impossible) for the prior mentioned confounding factors caused by fabric sample differences, we will prioritize presenting how the samples vary in their specifications and also lend insight into the objective real-world application measurement goal of the study. Both these aspects will help highlight how applicable the study is to materials used for weighted blankets.
The search for the perfect cover
We first started by examining what type of material would feel good against your skin, and help stop the sweat we read so much about in all your reviews. As someone with Aspergers, I cannot have a crease or even a breadcrumb in my bed. But, I don’t think I have OCD, because I am normally fine with having clothes all over the place. I really think I may be more sensitive to touch. A lot of the reviews we’ve read showed that people felt that some of their blankets were too bumpy and rocky (like there wasn’t enough stuff but too much weighted filler, either that or the cover wasn’t thick enough to prevent feeling the filler).
Hemp is more sustainable but too rough
First, we thought about hemp and cotton fabric combinations, but even the 20% hemp 80% cotton ratio was too rough to sleep with. Then we found bamboo. Bamboo seemed to be trending everywhere. We asked ourselves, “Should we sell bamboo just because it’s trending and there’s high demand?” Refusing to roll the dice on following the market, we dove deeper into the research.
Meeting our two goals
Thermal comfort properties
Doing our market research, we found many complaints that other blankets made out of cotton and other forms of synthetic material were too hot.
Trying to figure out what others haven’t yet
Immediately, we sought to discover what the thermal regulatory differences between bamboo and cotton were. First, we found a study titled “The investigation of thermal comfort, moisture management, and handle properties of knitted fabrics made of various fibers.” This study directly compared several important thermal comfort properties as shown below.
(Ozgen & Atlas, 2014)
But wait, what are the limitations?
They accounted for intrinsic material differences. These differences are innate to each material listed, with an acceptable level of variance.
(Ozgen & Atlas, 2014)
They also stated the knitting machine was set on the same tightness no matter what material was being sewn. That’s good to know.
(Ozgen & Atlas, 2014)
How cool will bamboo feel relative to cotton?
Excited, we read on to find out that the thermal conductivity of cotton was so much better than bamboo as seen below:
But then we saw…
though its thermal conductivity is low, higher thermal
absorptivity values could be explained with the lower fibre
fineness. Lower fibre fineness causes lower porosity with
less air involved within, leading to higher thermal
absorptivity and feel cooler. “
Ok, how about all my sweat? That is what wakes me up usually…not the heat itself
Hmmm, we asked ourselves the same question. Check out the graph below.
(Ozgen & Atlas, 2014)
(Ozgen & Atlas, 2014)
More on bamboo’s ability to absorb your sweat
They also directly measured the difference between the top and bottom wetting times, which is basically sticking each bit of cloth in water and seeing how fast it can soak through. We were already impressed by bamboo’s thermal regulation capabilities, but now this next paragraph confirmed that bamboo passed our ‘cool” part of “cool weighted blanket” test.
(Ozgen & Atlas, 2014)
But how about making sure our blanket is great for touch sensitivities?
For people (like myself) with autism, ADHD, sensory processing disorder, insomnia, or depression, the slightest bump in our bedding or unevenness will wake us up. Back then, we saw many customer complaints of feeling the weighted filler. So we made sure our blanket cover was thick enough to provide tactile comfort while being thin enough to be breathable.
Naturally soft and silky to human skin
According to this scientific study…bamboo feels more comfortably natural to human skin than cotton.
Future works
I will upgrade this post with why truHugs chose bamboo lyocell (basically using the same method as Tencel, but using bamboo cellulose) for truHugs ONE cover:
- Extremely hyped mechanically extracted bamboo linen (which is too rough for a sensory blanket, trust us, we tried, Google it, even the linen is too rough unless it’s combined).
- Bamboo viscose (the most common form of bamboo, the cheapest, manufacture requires dumping barrels of non-reusable solvents into our rivers every production run).
- Bamboo modal (has the least thermal regulating capabilities, best bamboo strain for clothing, I will update here why).
Primarily, it was because of our mission to support eco-friendly products while producing a soft cover that would emulate floating spas.
References
Ozgen, B., & Atlas, S. (2014). The investigation of thermal comfort, moisture management, and handle properties of knitted fabrics made of various fibres. Textiles and Apparel, 24(3), 272 – 278.
