| Added chemical binder | 0% by design | Binder may be applied as a liquid, foam, spray, or powder | Eliminating an added binder removes one potential source of binder-related VOCs and odor. It does not prove that total VOC emissions are zero. |
| Bonding mechanism | Heat softens or melts thermoplastic fibers, low-melt sheath fibers, or thermoplastic webs at selected bond points | A chemical binder forms adhesion between fibers after application and drying or curing | Thermal bonding can avoid binder drying and curing stages, which may reduce process emissions and drying energy. |
| Typical polymer components | Polyester, polypropylene, polyethylene, or bicomponent fibers with a lower-melting sheath | Fiber substrate plus an acrylic, styrene-butadiene, vinyl acetate, polyurethane, or other binder system | The exact polymer, additives, finishes, and processing temperature determine the final emission profile. |
| VOC emission status | No binder-derived VOC source is intentionally added | Potential emissions can originate from binder ingredients, coalescing agents, residual monomers, additives, or incomplete drying | “Lower VOC” is a design expectation, not a guaranteed numerical result without laboratory testing. |
| VOC measurement unit | Report measured emissions in µg/m³ or mg/m³, together with sampling time and chamber conditions | Use the same unit and test conditions for a valid comparison | A paired test using identical mass, area, conditioning, temperature, humidity, and sampling time provides the most meaningful comparison. |
| Relevant VOC test methods | ISO 16000-6 for VOC analysis; ISO 16000-9 for emissions from building and furnishing products; ASTM D5116 for small-chamber testing | The same methods should be used to maintain comparability | Test reports should identify the analytical method, chamber volume, air-exchange rate, temperature, relative humidity, and test duration. |
| Process drying or curing | No binder-drying or binder-curing step is required | Drying and, depending on the binder, curing may be required | Removing wet-binder handling can shorten the process route and reduce the opportunity for emissions from volatile formulation components. |
| Material add-on control | Bonding is created within the thermoplastic fiber structure; no binder add-on is required | Binder add-on must be controlled for solids content, distribution, and cure level | Lower formulation complexity can make source control and emissions troubleshooting easier. |
| Air permeability | Measured value depends on basis weight, thickness, fiber diameter, bonding area, and compression | Measured value depends on the same structural factors plus binder distribution and add-on | A real comparison must use the same test standard, pressure differential, basis weight, and sample conditioning. |
| Mechanical strength | Controlled by fiber type, web orientation, bonding temperature, pressure, pattern, and bond area | Controlled by fiber structure, binder chemistry, binder add-on, drying, and curing | Strength should be reported using a defined method such as ISO 9073-3 or an equivalent recognized standard. |
| Odor potential | Often lower when no odorous finish, lubricant, or volatile additive is present | May be influenced by binder formulation, residual volatiles, curing conditions, and storage history | Odor is not equivalent to VOC concentration; both sensory evaluation and instrumental testing may be required. |
| Recyclability considerations | A single-polymer or compatible-polymer construction can simplify recycling compared with a fiber-and-binder composite | Different fiber and binder chemistries may complicate material recovery | Recyclability depends on the complete formulation, product design, contamination level, and available recycling process. |
| What must be verified before making a VOC claim | Confirm total VOC emissions, individual compounds, aldehydes, odor, and any finish-related emissions | Use the same verification items and test conditions | A defensible claim should state the test method, detection limits, conditioning protocol, sampling time, and numerical results. |