Liquid binder composition for binding fibrous materials

A fibrous material comprising a binder composition distributed therein or coated thereon,

• wherein said fibrous material is selected from:
• a woven or nonwoven fabric;
• a nonwoven layer of randomly arranged fibers, fiber tows, yarns, braids, textile tape suitable for automated fibre placement (AFP) and/or automated tape laying (ATL), and
• wherein said binder composition comprises:
• (a) one or more multifunctional epoxy resins;
• (b) at least one thermoplastic polymer that is soluble in one or more epoxy resins upon curing of the epoxy resin(s);
• (c) one or more surfactants selected from:
• (i) nonionic surfactant which is mono or multi-functional block or graft block copolymers comprising hydrophilic and hydrophobic blocks;
• (ii) anionic surfactant which is represented by the following formula:
• A-R
• wherein R is an alkyl, aryl, aryl-alkyl, or an alkylene chain having 4-50 carbon atoms (C4 to C50);
• and A is lithium, sodium, potassium, ammonium, quaternary ammonium amine salt of a carboxylic-, or sulfonic-, or phosphoric acid group;
• and
• (iii) a combination of nonionic surfactant and anionic surfactant.

A resin-infusible preform comprising a plurality of fibrous materials assembled and bonded to each other, wherein the fibrous materials are held together by a binder composition comprising:

• (d) one or more multifunctional epoxy resins;
• (e) at least one thermoplastic polymer that is soluble in one or more epoxy resins upon curing thereof;
• (f) one or more surfactants selected from:
• (i) nonionic surfactant which is a tri-block copolymer comprising ethylene oxide(EO) and propylene oxide(PO), and is represented by the following formula (III):
• (EO)x-(PO)y-(EO)z (III)
• wherein x, y, z=integers or fractions provided that the ratio of (x+z) to y is 1.32 or higher, and the content of ethylene oxide is in the range of 50%-99% by weight, and
• wherein said tri-block copolymer has a number average molecular weight in the range of 1000 g/mol-100,000 g/mol;
• (ii) anionic surfactant which is represented by the following formula (IV):
• A-R (IV)
• wherein R is an alkyl, aryl, aryl-alkyl, or an alkylene chain having 4-50 carbon atoms (C4 to C50);
• and A is sodium, potassium, ammonium, amine salt of an carboxylic-, or sulfonic-, or phosphoric acid group;
• and
• (iii) a combination of nonionic surfactant of formula (III) and anionic surfactant of formula (IV), and
• wherein the amount of binder composition in the preform is up to 10% by weight based on the total weight of the preform.