There are basically two kinds of known retort adhesives.
One adhesive is based on an aliphatic-based isocyanate, which meet regulatory compliance, but the curing of such aliphatic-based isocyanate adhesives is very slow, and the adhesives have performance issues. The other type of adhesive contain aromatic isocyanates: and such aromatic-based isocyanate adhesive have fast curing but such adhesives do not meet regulatory compliance for retort applications and the adhesives also have performance issues. the prior does not disclose an “all-in-one” retort adhesive which meets regulatory compliance, has a fast curing property, and has good adhesion properties for retort applications.
For example, the laminating adhesives for retort applications:
(1) exhibit good adhesion performance for a wide range of retort substrates and structures, and the adhesives are generally compliant with global food regulations for retort applications; but the adhesives exhibit a slow curing property, such as being curable above 40℃ for at least 10 days, before packaging foodstuff in packages made using the laminating adhesives;
(2) are generally compliant with global food regulations of adhesives for retort applications; but the adhesives exhibit a slow curing property, such as being curable above 40℃ for at least 10 days, before packaging foodstuff in packages made using the laminating adhesives; and the adhesives do not exhibit good adhesion performance for a wide range of retort substrates and structures;
(3) exhibit a fast curing property, such as being curable at ambient conditions in 10 days or at an evaluated temperature (e.g., greater than or equal to 40℃ in five days; and the adhesives exhibit good adhesion performance on typical retort substrates and structures; but the adhesives are generally not compliant with global food regulations for retort applications, for example, the adhesives have issues complying with FDA and EU regulations. It is also known that aromatic-based adhesives do not exhibit good adhesion performance.
