Roofing and insulation play critical roles in a building’s envelope, providing structural integrity and climate regulation to keep those inside comfortable and protected from the elements.
The nonwovens that go into making these materials need to be strong and durable to endure daily wear-and-tear and occasional extreme weather events, as well as contribute to insulation performance and meet roofing regulations for many years.
BASF’s polymers, binders and additives for roofing and insulation nonwovens provide durability, thermoset or modifier properties, and cost and sustainability benefits to builders and contractors.
Nonwovens in roofing and insulation applications require a few key properties to be effective. Strong tear strength and tensile strength are important to ensure longevity and prevent failures in the nonwoven.
“Tensile strength is essentially the breaking strength of a fabric when it's being pulled in a longitudinal manner,” says John Norton, Technical Specialist at BASF. “Every textile needs a certain amount of tensile strength to get through the fabrication process and perform in its end-use application.”
Similar to tensile strength, tear strength is defined as the force required to start or continue a tear in fabric under specified conditions.
Poor tensile or tear strength can lead to failure in the production line -- or worse, in the end application, leading to a compromised building envelope.
“If you're making glass nonwovens that go into roofing shingles, for example, there’s a lot of tension on that nonwoven as it’s being pulled through the asphalt coating machine,” says Norton. “If it fails, it will break, and there's a lot of downtime on the shingle line if the glass nonwoven breaks.”
In insulation applications, strong tear and tensile strength prevent damage when handling, ensuring the soft insulation materials can rolled and unrolled without breaking during installation.
Raising the roof
BASF offers a number of high-performance water-based acrylic binders to enhance the strength and performance of glass fiber nonwovens used in roofing shingles.
ACRONAL® 4888 is a self-crosslinking styrene acrylic binder with acrylonitrile that provides strength and adhesion to polyester and glass nonwovens with outstanding thermal dimensional stability.
“ACRONAL 4888’s crosslinking provides great thermal dimensional stability,” says Norton. “That prevents the non-woven from stretching or necking at high temperatures when it's under high tension, so it’s often used in commercial building roofing applications or flat roofs.”
Used in both specialty glass mats and insulation, ACRODUR® 950 L is a formaldehyde-free crosslinking solution polymer emulsion for thermoset nonwovens for use in fiberglass, insulation, ceiling tiles, wall coverings and more. In roofing applications, it delivers excellent durability and stiffness.
Insulation and ACRODUR
On the insulation side, ACRODUR technology allows manufacturers to supply low-VOC emitting products, supports indoor air quality and helps reduce plant emissions. As a series of water-based acrylic binders, these additives are formaldehyde-free and can help replace traditional solvent-based resins such as melamine or urea.
“For the last 10 plus years, the glass insulation market has been moving away from thermosetting resins with formaldehyde,” says Norton. “We offer ACRODUR thermosetting solution resins that provide the strength and much of the other properties that insulation applications need, without formaldehyde.”
A compound of carbon, hydrogen, and oxygen, formaldehyde is used in construction materials, as well as in clothing and textiles, to provide crease-resistance and dimensional stability. It’s also a sensitizing agent that can trigger an immune response and cause irritation in the eyes, nose or throat and induce respiratory reactions, leading the FDA and EPA to limit its use.
ACRODUR PLUS 2580 is a popular additive in roofing applications, offering excellent durability and stiffness with very low color. Its high solid composition can help cut down on transportation costs, and it can also be used as a crosslinker.
Additional properties can be introduced to thermoset nonwovens with polymer emulsions like ACRODUR DS 3515 na and ACRODUR DS 3530.
“ACRODUR DS 3515 na and ACRODUR 3558 are modified ACRODUR products,” says Norton. “They’re pendants that react into the backbone of ACRODURs to modify some properties, and in many cases, these can make the dispersions more hydrophobic and less brittle.”
Choosing the right one
There are several ACRODUR additives providing a variety of different benefits useful in different scenarios and environments. BASF can help manufacturers and formulators choose the right additive for their needs.
Nonwovens and other composite materials help protect and boost performance in the building materials that help create our homes, schools and offices, and with innovations in chemistry we can design them to be stronger and more sustainable than ever before.
For more information on BASF’s additives for nonwoven applications, click here.