Gencorp, Inc.

Chia L Wang

Earl G Melby

H William Cocain

Robert L Spencer

Arden E Schmucker

Fred V Sandels

Richard H Harshbarger

A two-component urethane adhesive is disclosed which requires no primer or pretreatment of the substrate. The adhesive in cured form has superior paint adhesion and can withstand high temperature bake cycles without substantial losses in adhesion to the substrate. The adhesive differs from prior adhesives in that essentially all of the high molecular weight polyols in the prepolymer component are the reaction product grafting reactions of acrylonitrile onto polypropylene polyols.

Primerless urethane adhesive compositions

A two component primerless modified urethane adhesive having good high temperature stability can be utilized to bond substrates such as sheet molded composites together which can be subsequently powder coated. The utilization of the modified adhesive generally results in the formation of channels between the cured adhesive and the sheet molded composite surface so that upon cure of the applied powder coating, volatiles can escape from the sheet molded composite thus preventing blistering of the powder paint coating. The prepolymer component of the modified urethane contains a reacted hydroxyl intermediate and has a significant excess of free isocyanate. The curative component contains a polyol curing agent, an amine sag resistant agent, a trimerization catalyst, a low amount of urethane catalyst, and optionally a phosphorus-type adhesion promoter and/or molecular sieves. The equivalent ratio of free NCO groups in the prepolymer component to OH groups plus any amine groups in the curative component is generally from about 1.2 to about 2.0.

Two-component primerless modified urethane adhesive for powder coatings

A two component primerless modified urethane adhesive having good adhesion can be utilized to bond various substrates together such as sheet molded compounds. The prepolymer component of the modified urethane contains a reacted hydroxyl intermediate and has a significant excess of free isocyanate. The curative component contains a polyol curing agent, an amine sag resistant agent, a phosphorus-type adhesion promoter, and optionally molecular sieves. The equivalent ratio of free NCO groups in the prepolymer component to OH groups plus any amine groups in the curative component is generally from about 0.90 to about 1.25.

Two-component, primerless, organic phosphorus containing polyurethane

A two-component polyurethane composition has good shelf stability and the adhesive made by curing the same has good high temperature stability and no adhesion loss after high temperture bake. The base or prepolymer component containing a primary hydroxyl intermediate also has a sufficiently large excess of free isocyanate so that the ratio of free NCO groups in the prepolymer component to OH curative groups plus any amine groups in the curative component is generally from about 1.2 to about 2.0. The curative component contains a trimerization catalyst so that upon cure, isocyanurate units are produced. The system also contains molecular sieves, as well as phosphorous-type adhesion promoters.

Growing community of inventors

Hudson, OH, United States of America

Chia L Wang