Delivering Client Solutions with Polymer Sheet and Laminated Substrates
Bixby, a custom plastic extrusion company, leverages its extensive knowledge and experience in the application development process to deliver innovative product solutions for its clients. At the forefront of this effort is Bixby's R&D and product development team. The team is made up of industry professionals with decades of theoretical and practical experience designing with polymers and other substrates in a vast number of materials, end-use applications, and plastic conversion processes. Our approach to custom thermoplastic extrusion product development goes far beyond what other plastic sheet extrusion companies offer.
It is almost never as easy as it looks
Experience has taught Bixby that the success of development programs often depends on the integrity of bonds in laminated constructions. The approach taken by many OEM's,extruders and laminators without Bixby's unique capabilities typically begins with selecting individual polymer sheet layers, films, foams or fabrics based on end-use requirements. Based on those selections compatible adhesives, glues, or solvent systems with the appropriate rigid or flexural properties are identified. As simple as this method appears, it is never that easy, because each layer, whether it is part of a multiple core, substrate, or superstrate layer, must be carefully specified as part of a functioning system. The reason for this is that layers are typically obtained from separate suppliers, and consist of various chemistries, which must work together to make sure the "whole" meets the functional requirements of a specific application. Thus, each component layer and their chemistries or formulations need to be optimized across multiple suppliers. All of which makes this seemingly "simple" strategy more challenging, time consuming and difficult, especially if you are unable to control and manage the whole process under one roof.
Real world realities versus laboratory fantasies
The integrity of a laminate bond long term also can be put at risk by the downstream physical, functional and environmental requirements of the application. All too often the "strong" adhesion that was created in the controlled environment of a development lab delaminates in the field due to unforeseen contact with moisture, chemical reagents, high temps, strain or a myriad of other variables and combinations of such. This underscores the importance of partnering with a company with the knowledge and experience necessary to sort through the many complexities that confront both vendors and clients.
A strong bond begins and ends with a strong process
Extrusion lamination is at the heart of Bixby's process. The company's success stems from the fact that it has relationships with many dozens of material suppliers and their technical experts. This enables Bixby to choose and formulate, if necessary,the core thermoplastics, hot melt polymers, additives, and superstrate and substrate materials to assure compatibility within a laminate system. Moreover, Bixby's process enables it to gain a thermal melt bond in-process often without the need for additional adhesive chemistries. This is achieved by extruding the molten polymers and hot melts directly to each functional polymer layer or between the various layers of fabrics, foams or other substrates that might be used. If any of this is found to be incompatible, Bixby can modify material and tie layer compositions, or surface treatments to allow proper wet out and bond at the material interfaces. This is crucial because it is the part of the process where bond integrity is best optimized.
How to ensure the utmost in bond integrity
Functional material interface layer chemistries, and the proper tie layer for those play a key role in achieving optimum bond strength. It often comes down to hot melt chemistries, which is why it is crucial to choose the correct materials. However, this phase of the process, like much of everything that preceded it, is not cut and dry. There is a near limitless number of hot melt chemistries available from a broad list of large global and custom material suppliers, compounders and formulators. To complicate matters further, within each tie layer or hot melt chemistry, there are dozens of grades available that are engineered for specific purposes.
Bixby not only knows and works daily with a myriad of commercial hot melt chemistries, it also formulates its own hot melts for custom applications. These not only assure a good bond, but can also provide additional functionality such as conductivity, UV blocking, and color, if required for the end-use application. Furthermore, custom laminate constructions that go into Bixby's process permit core layer materials to be made compatible or functionalized for adhesion to specific hot melts or other core layers in processing.
More is needed to guarantee success
The extrusion lamination process and hot melt chemistries are just two components that are carefully considered by Bixby's R&D team. However, to deliver innovative product solutions, the team must also make sure these two elements are in sync with the client's end-use processes. Some of the variables they take into account are tie layer thickness, substrate properties and interactions, and downstream application temperatures, pressures and times.
Another area the team is mindful of is that in many applications, bond strength takes time to grow, so testing immediately after production can be misleading. In addition, post processes conducted on the laminate to fabricate a final product such as thermoforming, cutting and sewing can also compromise an application's ultimate bond strength.
These two examples illustrate why it is critical to select and test the tie layers and the interactions of all substrates used in a laminate for performance in the same mode in which the product will ultimately be used. That goes from selection, processing, assembly, and through to the final product's use environment. These examples also underscore why it is so important to partner with a company like Bixby International- the custom thermoplastic sheet extruder and laminator with more than 140 years of knowledge and experience.