STRUKTOL® POLYDIS®, POLYVERTEC® and POLYPHLOX® Additives for Prepregs in Composite Applications

Composites based on prepregs are used in a wide range of applications:

  • Aerospace industry: aircraft fuselages and wings, empennages.
  • Transportation (rail, marine): railcar construction, ship superstructures
  • Wind energy: rotor blades
  • Sports and leisure industry: golf clubs, bicycles, fishing rods, etc.

Prepregs are textile fiber semi-finished products that are pre-impregnated with reactive resins such as epoxy resins. For the production of very high-quality fiber composite components, prepregs are cured in the form of laminates under pressure and temperature.

With STRUKTOL® POLYDIS® and POLYVERTEC® modifiers, e.g. the tack and mechanical properties such as toughness of the prepreg material can be specifically adjusted and increased. In this way, high-performance composite parts (CFRP/GFRP) can be produced, which are often characterized by very low weight and extreme strength and stiffness.

STRUKTOL® POLYPHLOX® Flame Retardant modifiers based on halogen-free phosphorus compounds improve the fire behavior of the material and composite parts made from it.

CTBN modified epoxy resins are prepolymers that are obtained by reaction of nitrile rubber with epoxy resins. These versatile products offer significant improvement in technical properties such as impact strength, tensile shear strength, flexibility and adhesion to oily steel.  

Typical applications are adhesive formulations, coating systems, casting resins, prepregs and epoxy resin systems in the fiber composite industry.

Struktol® Polydis® 3610

Nitrile rubber modified epoxy prepolymer based on DGEBA

  • Resin replacement: 10-35 %
  • Epoxy equivalent weight: 600 g/Eq
  • Dyn. Viscosity at 80 °C: 100 Pa.s
  • Appearance: amber, solid resin, exhibiting cold flow
  • This product provides ultimate toughening and best adhesion especially on oily steel for 1-component-systems
Struktol® Polydis® 3611

Nitrile rubber modified epoxy prepolymer based on DGEBF

  • Resin replacement: 10-35 %
  • Epoxy equivalent weight: 550 g/Eq
  • Viscosity at 80 °C: 30 Pa.s
  • Appearance: amber, resin paste
  • This product provides ultimate toughening and best adhesion especially on oily steel for 1-component-systems
Struktol® Polydis® 3614

CTBN modified Bisphenol-A Epoxy Resin (DGEBA)

  • Improvement of lap shear strength, impact strength in adhesive systems
  • Minimal influence on glass transition temperature and Young's modulus
  • Dosage (replaces base resin): 10-40 %
  • Epoxy equivalent weight: 330 g/Eq
  • Elastomer content: 40 %
  • Dyn. viscosity (25 °C): 470 Pa.s
  • Appearance: yellowish, highly viscous liquid
Struktol® Polydis® 3633

Bimodal elastomer-modified epoxy resin (DGEBA/DGEBF)

  • Improvement of T-peel strength, lap shear strength, impact resistance
  • Can be used as a modified raw material component in epoxy resin formulations
  • Minor influence on glass transition temperature and Young's modulus
  • Dosage (replaces base resin): 40-100 %
  • Epoxy equivalent weight: 220 g/Eq
  • Elastomer content: 16 %
  • Dyn. viscosity (25 °C): 25 Pa.s
  • Appearance: amber liquid resin
Struktol® Polydis® 3636

CTBN-modified high molecular epoxy resin

  • Improvement of T-peel strength, lap shear strength, impact resistance
  • Can be used as a modified raw material component in epoxy resin formulations
  • Dosage (replaces base resin): 40-100 %
  • Epoxy equivalent weight: 300 g/Eq
  • Dyn. viscosity (40 °C): 200 Pa.s
  • Appearance: yellowish, highly viscous resin
Struktol® Polydis® 3652

CTBN-modified epoxy prepolymer based on solid resin

  • Improvement of T-peel strength, lap shear strength, impact resistance
  • Combines properties of Polydis® 3614 with the good properties of high molecular weight epoxy resins
  • Well suited for the formulation of reactive hot-melt adhesives
  • Dosage (replaces base resin): 50-100 %
  • Epoxy equivalent weight: 360 g/Eq
  • Dyn. viscosity (80 °C): 15 Pa.s
  • Appearance: yellowish, paste-like resin

NBR modified epoxy resins are prepolymers that are formed by the reaction of nitrile butadiene rubbers with epoxy resins. These products are particularly suitable for increasing tack in adhesive and prepreg resin formulations and for adjusting the resin flow of prepreg systems (resin flow).

Struktol® Polydis® 3691

Nitrile rubber modified Bisphenol-A Epoxy Resin (DGEBF)

  • Application in adhesives to improve T-peel strength and contact adhesion
  • Tack and resin flow adjustment in prepregs
  • Dosage (replaces base resin): 10-15 %
  • Epoxy equivalent weight: 205 g/Eq
  • Dyn. viscosity (50 °C): 12 Pa.s
  • Appearance: yellowish-cloudy resin
Struktol® Polydis® 3693

Nitrile rubber modified epoxy resin (DGEBF), lower viscosity than Polydis® 3691

  • Application in adhesives to improve T-peel strength
  • Tack and resin flow adjustment in prepregs
  • Dosage (replaces base resin): 10-15 %
  • Epoxy equivalent weight: 180 g/Eq
  • Dyn. viscosity (50 °C): 8 Pa.s
  • Appearance: yellowish-cloudy resin
Struktol® Polydis® 3694 S

Nitrile rubber modified Bisphenol-A Epoxy Resin (DGEBA) in MEK (70% solution)

  • Application in adhesives to improve T-peel strength
  • Tack and resin flow adjustment in prepregs
  • Dosage (replaces base resin): 10-20 %
  • Epoxy equivalent weight: 290 g/Eq
  • MEK content: 30 %.
  • Appearance: yellowish-cloudy liquid
Struktol® Polydis® 3695

Nitrile rubber modified Bisphenol-A Epoxy Resin (DGEBA)

  • Application in adhesives to improve T-peel strength
  • Tack and resin flow adjustment in prepregs
  • Dosage (replaces base resin): 10-15 %
  • Epoxy equivalent weight: 195 g/Eq
  • Dyn. viscosity (80 °C): 7 Pa.s
  • Appearance: yellowish-cloudy resin

The elastomer modified epoxy resins are  rubber-free prepolymers that are created by the reaction of polymers with epoxy resins. The polymers used for this purpose primarily belong to the following groups: dimer fatty acids, polyols, polyurethanes, polyetheramines or thermoplastics.

These products, like CTBN-modified epoxy resins, improve technical characteristics such as impact strength, lap shear strength and adhesive strength. Depending on the modification, the handling of the rubber-free epoxy resins is easier, with an improvement in performance similar to the CTBN-modified epoxy resins.

Typical applications are adhesive formulations, coating systems, casting resins, prepregs and epoxy resin systems in the fiber composite industry.

Struktol® Polycavit® 3530

Polyurethane prepolymer blended with epoxy resin

  • Improvement of peel strength, tensile shear strength, impact strength
  • suitable in particular for the formulation of 1-component structural adhesives
  • Synergistic effects with CTBN-Tougheners
  • Application temperatures -40 to +150°C
  • Dosage (replaces base resin): 8-30 %
  • EEW: 460 g/Eq
  • Toughener content: 60 %.
  • Viscosity at 40 °C: 25 Pa.s
  • Appearance: yellowish liquid
Struktol® Polycavit® 3550

Epoxy functional polyester/polyether Copolymer

  • Improvement of peel strength, impact strength, flexural strength
  • improved adhesion on galvanized steel
  • suitable for the formulation of adhesive systems and resin system for composites
  • applicable up to 200°C without loss of properties
  • Dosage (replaces base resin): 5-15 %
  • EEW: 1,800 g/Eq
  • Toughener content: 100 %.
  • Dyn. viscosity (25 °C): 400 Pa.s
  • Appearance: yellowish, viscous liquid
Struktol® Polycavit® 3570

Polyetheramine-modified epoxy resin

  • Improvement of peel strength, tensile shear strength,
  • improved adhesion on galvanized steel
  • suitable for the formulation of adhesive systems
  • Dosage (replaces base resin): 10-25 %
  • EEW: 325 g/Eq
  • Toughener content: 40 %.
  • Dyn. viscosity (25 °C):  95 Pa.s
  • Appearance: yellowish, viscous liquid

Reactive flame retardants based on phosphorous-organic compounds such as DOPO are a very effective and toxicologically safe alternative to halogen-containing flame retardants.

STRUKTOL® POLYPHLOX® products are chemically pre-treated so that they later react with the matrix in epoxy resin systems. This has little effect on the mechanical and chemical properties of the cured EP matrix, so that for many applications the respective optimum property profile and good fire protection (e.g. UL94 V0) can be achieved.

The products can often be combined well with synergists such as APP, melamine cyanurates or ATH, so that the fire protection effect can be further enhanced.

Struktol® Polyphlox® 3735

Multi-functional, organophosphorous modified epoxy Novolak resin (based on Struktol® Polyphlox® 3710)

  • Epoxy equivalent weight: 350 g/Eq
  • Softening point: 80 °C
  • Phosphorous Content: 3.8 %
  • Appearance: transparent – yellowish solid resin
Struktol® Polyphlox® 3742

Multifunctional, organophosphorus modified epoxy resin (based on Struktol® Polyphlox® 3710)

  • Halogen-free flame retardant especially suitable for prepregs and composite materials, e.g. in aerospace and transportation
  • DOPO (Polyphlox® 3710) modified epoxy resin
  • Epoxy equivalent weight: 370 g/Eq
  • Softening point: 57 °C
  • phosphorus content: 4.0 %
  • appearance: yellowish, semi-solid resin
Struktol® Polyphlox® 3742 S

Multifunctional, organophosphorus modified epoxy resin (based on Struktol® Polyphlox® 3710)
Solvent content 20% (MEK)

  • Halogen-free flame retardant especially suitable for prepregs and composite materials, e.g. in aerospace and transportation
  • DOPO (Polyphlox® 3710) modified epoxy resin
  • Epoxy equivalent weight: 460 g/Eq
  • Phosphorus content: 4.0 % (solids content)
  • MEK share: 20 %
  • Appearance: yellowish resin in MEK
Struktol® Polyphlox® 3743

Multifunctional, organophosphorus modified epoxy resin (based on Struktol® Polyphlox® 3710)

  • Halogen-free flame retardant especially suitable for prepregs and composite materials, e.g. in aerospace and transportation
  • DOPO (Polyphlox® 3710) modified epoxy resin
  • Epoxy equivalent weight: 350 g/Eq
  • Dyn. viscosity (80 °C): 13 Pa.s
  • Phosphorus content: 4.0 %
  • Appearance: yellowish, semi-solid resin
Struktol® Polyphlox® 3721

Flame retardant epoxy resin formulation with very high phosphorous content
UL94 V0 achievable

  • low viscous, flame retardant epoxy resin formulation  
  • for processing by hand lamination or RTM
  • APP-modified epoxy resin
  • Epoxy equivalent weight: 240 g/Eq
  • Dyn. viscosity (25 °C): 3 Pa.s
  • Phosphorus content: 5.1 %.
  • Appearance: whitish, opaque resin
  • suitable Polyvertec® hardeners: H4, H6, H7, H81
Struktol® Polyphlox® 3722

Flame retardant epoxy resin formulation with high phosphorus content
UL94 V0 compliant

  • medium viscous, flame retardant epoxy resin formulation  
  • for processing in hand laminate or infusion/injection process
  • DOPO- (Polyphlox® 3710) and APP modified epoxy resin
  • Epoxy equivalent weight: 215 g/Eq
  • Dyn. viscosity (25 °C): 12 Pa.s
  • phosphorus content: 4.2 %.
  • Appearance: whitish, opaque resin
  • suitable Polyvertec® hardeners: H4, H6, H7, H81