Flexible reinforcing fiber yarn pre-impregnated with resin

Abstract

A pre-impregnated yarn having a bundle made of reinforcing fiber filaments impregnated with a first resin composition infiltrated into the pre-impregnated yarn and at least partially connected via the first resin composition. The first resin composition contains at least two bisphenol A epichlorohydrin resins H1 and H2 in a weight ratio H1:H2 of 1.1 to 1.4, and an aromatic polyhydroxy ether P1. The pre-impregnated yarn has a second resin composition on the bundle outer side in the form of adhesive particles or drops. The second resin composition is solid at ambient temperatures and has a melting temperature in the range from 80 to 150° C. The bundle interior and at least 50% of the surface of the bundle outer side are free of the second resin composition.

1 . A pre-impregnated yarn comprising:
 a bundle of reinforcing fiber filaments with a bundle interior and a bundle outer side,   a first resin composition comprising at least two bisphenol A epichlorohydrin resins H1 and H2 in a weight ratio H1:H2 of 1.1 to 1.4, and   a second resin composition on the bundle outer side in the form of particles or drops adhering to the reinforcing fiber filaments,   wherein:
 the reinforcing fiber filaments are impregnated with the first resin composition infiltrated into the pre-impregnated yarn and the filaments of the pre-impregnated yarn are at least partially connected via the first resin composition, 
 H1 has an epoxy value of 1850 to 2400 mmol/kg and an average molecular weight M N  of 800 to 1000 g/mol and is solid at ambient temperatures, 
 H2 has an epoxy value of 5000 to 5600 mmol/kg and an average molecular weight M N  of <700 g/mol and is liquid at ambient temperatures, 
   the pre-impregnated yarn has 0.1 to 2 wt. % of the first resin composition in relation to the total weight of the yarn,
 the first resin composition further contains-comprises an aromatic polyhydroxy ether P1, which has an acid value of 40 to 55 mg KOH/g and an average molecular weight M N  of 4000 to 5000 g/mol, 
 the second resin composition is solid at ambient temperatures, has a melting temperature in the range from 80 to 150° C. and is present on the bundle outer side in a concentration of 0.5 to 10 wt. % in relation to the total weight of the pre-impregnated yarn, 
 at least 50% of the surface of the bundle outer side is free of the second resin composition, and 
 the bundle interior is free of the second resin composition. 
   
     
     
         2 . The pre-impregnated yarn according to  claim 1 , wherein the first resin composition comprises the bisphenol A epichlorohydrin resins H1 and H2 and the aromatic polyhydroxy ether P1 in a weight ratio (H1+H2):P1 of 0.05 to 0.8. 
     
     
         3 . The pre-impregnated yarn according to  claim 1 , wherein the first resin composition is present in a concentration of 0.4 to 1.2 wt. % in relation to the total weight of the pre-impregnated yarn. 
     
     
         4 . The pre-impregnated yarn according to  claim 1 , wherein the second resin composition comprises at least 50 wt. % of a compound selected from the group consisting of a bisphenol A epichlorohydrin resin H3 with an epoxy value of 480 to 645 mmol/kg and an average molecular weight M N  of 2700 to 4000 g/mol, an aromatic polyhydroxy ether P2, a polyamide, a polyethylene, an ethylene copolymer, a thermoplastic polyurethane resin, and mixtures thereof. 
     
     
         5 . The pre-impregnated yarn according to  claim 1 , wherein the second resin composition has an adhesive strength of at least 5 N at a temperature of 20° C. above the melting temperature of the second resin composition, in relation to an adhesive surface with a diameter of 25 mm. 
     
     
         6 . The pre-impregnated yarn according to  claim 1 , wherein the particles or drops of the second resin composition adhering to the reinforcing fiber filaments have a size less than 300 μm. 
     
     
         7 . The pre-impregnated yarn according to  claim 6 , wherein the particles or drops of the second resin composition adhering to the reinforcing fiber filaments have an average size in the range from 20 to 150 μm. 
     
     
         8 . The pre-impregnated yarn according to  claim 1 , wherein the concentration of the second resin composition is greater than that of the first resin composition. 
     
     
         9 . The pre-impregnated yarn according to  claim 1 , wherein the total concentration of the first resin composition and second resin composition is from 2 to 7 wt. % in relation to the total weight of the pre-impregnated yarn. 
     
     
         10 . The pre-impregnated yarn according to  claim 1 , wherein the first resin composition and/or the second resin composition is free of curing agents. 
     
     
         11 . The pre-impregnated yarn according to  claim 1 , wherein the yarn comprises synthetic or natural fibers selected from the group consisting of carbon fibers that are obtained from pitch, polyacrylonitrile, lignin, or viscose pre-products, aramid fibers, glass fibers, ceramic fibers, boron fibers, and a combination thereof. 
     
     
         12 . The pre-impregnated yarn according to one or more of  claim 1 , wherein the pre-impregnated yarn is present as a flat band that has a ratio of yarn width to yarn thickness of at least 20. 
     
     
         13 . The pre-impregnated yarn according to  claim 12 , wherein the flat band has a ratio of yarn width to yarn thickness in the range from 25 to 60. 
     
     
         14 . A textile structure comprising the pre-impregnated yarns according to  claim 1 . 
     
     
         15 . The textile structure according to  claim 14 , wherein the pre-impregnated yarns are connected to each other at points of mutual contact at least via the second resin composition.