Components of Fiber Sizing

Glass fiber sizing formulations are liquids that are coated on the glass fibers and are composed of film-forming binders, silane coupling agents, and additives such as lubricants, rheology modifiers, and antistatic agents. In terms of optimizing sizing technology, finding multifunctional ingredients that can reduce formulation costs while increasing the value of formulations through enhanced protection and performance is key. Roquette's POLYOX™ polymers do just that.

POLYOX™ Polymers

POLYOX™ products are thermoplastic polyethylene oxide resins based on nonionic water-soluble polymers with high molecular weights.

Structurally, they are long linear polymer chains with ether linkages and hydroxyl groups that promote hydrogen bonding, creating a variety of properties listed below that are useful in glass fiber sizing formulations.

 

• Lubricity
• Rheology modification
• Wet tack and nontacky when dry

Lubricity

Most glass fiber sizing formulations are water based, allowing POLYOX™ to not only be incorporated easily but also provide lubricity benefits. The chemical structure of POLYOX™ is extremely effective in binding water due to the chemical structure described above. Accordingly, when glass fibers are coated with POLYOX™, they gain increased protection from wear, owing to a layer of water molecules that are bound to each fiber. POLYOX™, being a long, flexible polymer, also helps conform around the various fiber shapes present in bundles and stay attached during handling and processing.

Rheology Modification

The high molecular weight of POLYOX™ polymers helps increase and control the viscosity of sizing formulations to desired specifications. POLYOX™ functions as a nonassociative thickener, meaning that the polymer chains themselves form an entangled web that stabilizes and thickens solutions. The resultant increased viscosity helps the sizing formulation encapsulate glass fibers without excessive dripping.

Wet Tack and No Tackiness When Dry

When POLYOX™ is in solution, it exhibits a high degree of tack, making it useful in modifying rheology. Specifically, the hydrogen bonding capabilities of POLYOX™ allow solutions to effectively adhere interfacially to glass fiber surfaces. When sizing formulations are dried, POLYOX™ does not remain tacky, preventing hindrance in further processing and handling of fibers in processes such as pultrusion and composite material manufacturing.

Other Benefits

There are several other benefits that POLYOX™ inherently provides in glass fiber sizing formulations. Being a nonionic polymer, POLYOX™ is highly compatible with many other ingredients in sizing formulations. POLYOX™ also provides antistatic properties that can reduce the need for adding separate antistatic additives. Most importantly, POLYOX™ delivers all the aforementioned benefits at extremely low use rates.

Grade Selection

POLYOX™ polymers are available in a range of options that vary in terms of molecular weight, which correlates to the viscosity each will provide when put in solution. Below, a table is provided comparing each grade based on these properties to help with selecting the right grade. The recommended addition rate of POLYOX™ in glass fiber sizing formulations typically ranges up to 1 wt%.

Summary

POLYOX™ is a line of multifunctional polymers that provide a host of benefits in glass fiber sizing formulations that may reduce or eliminate the added costs of using separate ingredients. Stemming from its long polymer chains and water-binding properties, POLYOX™ reduces wear and improves formulation coverage through its lubricating, rheology-modifying, wet-tack, and antistatic properties. Being a nonionic polymer, it is highly compatible with a variety of formulations. Click below to discuss your glass fiber sizing formulation with one of our experts and request a sample.