Adhesives for Coil Coating: Single and Two Stage Curing


Developed in the 1930s, the coil coatings process is an efficient, cost-effective, method of applying coatings and/or adhesives onto a rolled metal (coil) substrate in a continuous process. Once properly cleaned and treated, coatings and/or adhesives can be applied to one or both sides simultaneously and then recoiled, to be sent for processing (slitting, stamping, forming, etc.) to prepare the metal substrate for its final end use. A coil-coated adhesive can be used as a single-phase, in-line laminating adhesive, or it can be formulated to be dried online and suspended in a B-Stage state. Like a coil coating, the B-Staged adhesive will remain in place and stable throughout all necessary post-processing procedures. Once the metal substrate is ready for the final use, the adhesive is then activated using heat and, with proper pressure, used to laminate a second substrate to the metal part. Examples are: Vinyl or Olefin films to metal, roofing anchors to various types of membranes, brake shoe plates to composite pieces, etc. Coil coating provides an extremely efficient, cost-effective method of applying adhesives or coatings to metal coils with a continuous, nonstop process.

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Coil Coating Helps Address Adhesion Challenges

Fabricators often experience challenges with the proper adhesion of various coatings or industrial adhesives. Off-the-shelf adhesive formulations may not provide the exact characteristics required for the project, whereas a custom adhesive formulator can develop solutions that work in specific application parameters. As a custom formulator of coil coatings and adhesives, UNICHEM will work with an experienced coil coater to provide long-term, customer-specific solutions to address difficult adhesion and performance challenges. We work together to develop and provide a fully customized adhesive or coating formulation to meet the specifications required by the original equipment manufacturer (OEM).

One particular challenge many OEMs experience is the non-forgiving specific temperature range requirements for curing. More flexible temperature ranges for curing allow OEMs to address these challenges and achieve consistent curing across the entire width of the coil.

Single-Stage and Dual-Stage Curing Adhesives

Dual-stage curing, also called two-stage or B-stage, refers to a process of curing that utilizes a low-temperature cure step, which only partially cures the adhesive. This B-Staged adhesive is then activated, in the final application process, where it is completely cured, using heat and pressure, in the final lamination process. Two-stage curing allows products to be held for a period of time, without sacrificing performance, prior to a final lamination process. Many high-performance adhesives can be formulated with two-stage curing systems so that the adhesive/metal substrate can be stored for long periods of time and then reactivated utilizing heat and pressure in the laminating process to bond the two substrates together, creating a permanent, thermal-set bond.

Two-Stage Adhesive Curing Beneficial in Many Industries

Two-stage adhesive curing systems provide many benefits to a vast number of industries with an initial low-temperature curing system that does not compromise bond strength or processing quality upon reactivation. Many industries and applications, such as automotive, mechanical engineering, building materials, and electronics, continue to increase demand for lightweight construction with multi-material design.

Two-stage, heat-activated, laminating adhesives achieve full bonding strength within seconds upon exposure to heat and pressure. This allows for excellent substrate positioning accuracy with very rapid, permanent bond strength, eliminating the potential for slip and substrate misplacement, which can occur using liquid adhesives or mechanical bonding. Dual-stage curing adhesives form reliable structural bonds within seconds and can be formulated to provide additional functional attributes, such as moisture and vapor barrier properties, corrosion protection, flame resistance, insulative properties, sound dampening, etc.

uniBOND Industrial Adhesive Provides Two-Stage Curing Solutions

Universal Chemicals & Coatings, Inc., UNICHEM, is a custom coating and adhesive manufacturer offering single and two-stage adhesive formulations to meet a variety of processing requirements. uniBOND industrial adhesives are available in various formulations for bonding various substrates to fiber composites, polypropylene, polyethylene, vinyl, PVC, etc. uniBond adhesives are all available with single-stage or two-stage curing properties.

UNICHEM is an industry-leading custom coatings and adhesives supplier offering more than 50 years of experience. Our dedicated teams offer market and technology specialization with a keen understanding of customer expectations. Contact us to learn more about the many benefits achieved when coil coating with two-stage adhesives.