Binders-for-glass-fiber-sizing

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Glass-fiber reinforced plastics (GRPs) and carbon-fiber reinforced plastics (CFRPs) are found in cars, household appliances, sports equipment and numerous other everyday items. But before such fibers can reinforce plastics, they are usually pretreated by sizing.

Benefits of Baybond® polyurethane dispersions

Baybond® products are aqueous polyurethane dispersions that include both polyester and polyether polyurethanes based on aliphatic and/or cycloaliphatic isocyanates. Unlike many competing products, Baybond® products feature an ionic/non-ionic hydrophilic modification, a combination that ensures:

Good compatibility with other size components
pH stability
Good thermal stability
High shear stability

Glass and carbon fiber sizes based on Baybond® have excellent film-forming properties and very good adhesion while good colorfastness is maintained even at high temperatures. Some Baybond® products contain crosslinker dispersions blocked with butanone oxime or caprolactam. This improves the mechanical properties of thermoplastics – higher tensile strength and modulus of elasticity – as a result of thermal post-curing in the compound.

The following table shows the improvement of mechanical properties of a polyamide compound (30% glass). The fiber sizing is based on Baybond® PU 405 vs. a standard grade size.

Matrix	Sizing	Tensile strength [Mpa]	Flexural strength [Mpa]	Impact strength [kJ/m²]	Yellowness index
PA 6	Standard	189	283	61.9	74
PA 6	Baybond® PU 405	192	288	68.1	57

Overview / table of the major Baybond® grades and their properties:

Product	Chemical base	Glass fiber (GF) Carbon fiber (CF)	Thermo- plastic	Thermo- set
Baybond® PU 130*	Polyether	GF	X
Baybond® PU 239*	Polyether	GF / CF	X	X
Baybond® PU 330	Polyether	GF / CF		X
Baybond® PU 407	Polyether	GF	X
Baybond® PU 401	Polyether	GF / CF	X
Baybond® PU 403*	Polyether	GF	X
Baybond® VP LS 2277	Polyether	GF	X
Baybond® XP PU 405*	Polyether	GF / CF	X
Baybond® XP 2569	Polyether	GF / CF	X
Baybond® XP 2728	Polyether Polycarbonat	GF / CF	X
Baybond® LP RSC 3497	Polyether	GF	X	X
Baybond® PU 406	Polyether	GF	X
Baybond® PU 571 XP	Polyether	GF	X