Fabric-reinforced bonding sheet comprising an epoxy resin and dianiline and use thereof to make an insulated rail joint
AssigneeMinnesota Mining and Manufacturing Company
InventorBruce A. Marteness
Life of this patent
Estimating the term…
Abstract
Fabric-reinforced adhesive bonding sheet, the adhesive of which is a blend of epoxy resin and a dianiline which soften and melt at 50.degree.-110.degree. C. The bonding sheet is especially useful for making insulated rail joints.
Claims13
A pre-form which fits the facing surfaces of the joint bar and rails of a rail joint and comprises at least one layer of a fabric-reinforced bonding sheet comprising at least one layer of a reinforcing fabric saturated with a resin composition comprising an intimate blend of (a) 1,2-epoxy resin having a Durrans' softening point of 50.degree.-110.degree. C. and (b) within 15% by weight of an equivalent amount of a dianiline having a melting point of 50.degree.-110.degree. C., which bonding sheet can be stored for months at ordinary room temperatures but its resin composition fully cures at any time to a strong, tough thermoset state when heated to about 140.degree. C. for about 25 minutes.
A rail joint comprising a pair of rails, a pair of joint bars, means bolting the joint bars to the rails, and a fabric-reinforced cured resin composition bonding the joint bars to the rails, wherein the improvement comprises:
- said cured resin composition is the cured product of a mixture of (a) 1,2-epoxy resin having a Durrans' softening point of 50.degree.-110.degree. C. and (b) within 15% by weight of an equivalent amount of a dianiline having a melting point of 50.degree.-110.degree. C.
Method of making a fabric-reinforced bonding sheet comprising the steps of
- (1) providing a powder mixture, substantially all of which has a particle size less than 20 micrometers, comprising
- (a) 1,2-epoxy resin having a Durrans' softening point of 70.degree.-110.degree. C. and
- (b) within 15% by weight of an equivalent amount of a dianiline having a melting point of 70.degree.-110.degree. C.,
- (2) fusing the powder mixture to provide an intimate blend,
- (3) immediately saturating a reinforcing fabric with the fused blend, and
- (4) quickly cooling the blend before there is any appreciable reaction between the epoxy resin and the dianiline to provide a fabric-reinforced bonding sheet.
Dependencies are inferred from the claim text.