FIELD: chemistry.
SUBSTANCE: present invention relates to a polyurethane-forming system for making reinforced polyurethane composites by vacuum infusion, and to composites, made from said system. Described is a polyurethane-forming system, having viscosity at 25 °C equal to less than 600 mPa⋅s for not less than 30 min, time of gel formation at ambient temperature more than 60 min, and water content less than 0.06 wt% in terms of total weight of system, comprising: a) an isocyanate component having a viscosity at 25 °C equal to about 20 to about 300 MPa⋅c, including diisocyanate or polyisocyanate, and b) interacting with isocyanate component, including: (i) one or more polyols, having viscosity at 25 °C equal to 20 to 850 mPa⋅s, and OH number, equal to about 200 to about 600, (ii) to about 6 wt%, in terms of entire component interacting with isocyanate, fluidity-increasing additive, and (iii) from about 2 to 6 wt%, in terms of entire component interacting with isocyanate, drying agent, where sum expressed in wt% of amounts of all components of component interacting with isocyanate component is equal to 100 wt%, and c) optionally up to 1 wt% additives, which do not cause foaming, wherein components a) and b) react in such quantities that NCO index is equal to 99 to 110, to form polyurethane, having strength in uncured state, sufficient for separation from mould at ambient temperature not later than 6 hours. Invention also discloses a method of making fibre-reinforced polyurethane composite from a system by vacuum infusion, involving: 1) degassing each of components a) and b), 2) combining degassed components a) and b) to obtain a polyurethane-forming reaction mixture, 3) applying vacuum-generated pressure on dry reinforcing fibre material so that in reinforcing fibre material by infusion is introduced polyurethane-forming reaction mix and fibre-reinforced polyurethane composite obtained by said method.
EFFECT: making large composites, such as wind turbine blades, having excellent physical characteristics.
16 cl, 3 tbl, 1 dwg
