I. Process for polyester polyol manufacturing:
Key features of our polyester technology are:
Operates under milder reaction conditions – reaction temp. below 80oC in 8 – 14 hrs
Does not involve the use of any metal catalyst – no contamination of metals in the final polyesters.
Biphasic solvent process – water produced as a by-product stays in one layer and the polyester stays in a separated layer. Once the reaction is complete, polyester is separated from solvent where the by-product water is retained. Therefore, in our process, the removal of water is not at all necessary. In the conventional polyester polyol manufacturing process, without the removal of water, the reaction reaches equilibrium and complete conversion and yield cannot be achieved.
Polyester can be easily separated by decantation from the solvent phase. This leads to the final polyester which will be free from any residual unreacted acids. Glycol dilution is not necessary due to the loss of glycol, as predicted in the conventional process.
No inert gas such as nitrogen and no vacuum is needed in our process as it can be run in a closed batch reactor at 80oC or below and the water generated will be miscible with the solvent medium. To make the highest conversion and yield in the conventional manufacturing process, removal of the water from the reaction mixer is very critical.
The solvent can be reused - After the separation of polyesters, the solvent phase which contains water can be heated under vacuum to remove the water from the solvent and reused.
More importantly, the formation of 1.4-dioxane can be eliminated as our process runs below 100oC. According to the literature, glycol such as diethylene glycol tends to break and produce 1,4-dioxane at elevated (> 200oC) temperatures. The formation of unwanted by-products such as 1,4 Dioxane, is a major challenge to control in the conventional process as it operated above 200oC.
The process worked smoothly in the lab-scale (1 gallon batch) for all aliphatic and aromatic polyesters in high yield. The scale-up of the process is not completed.
We have completed the prototype process in the laboratory scale for some model polyesters including diethylene glycol adipate with OHN 245 g KOH/kg with functionality 2. Other polyesters studied are ethylene glycol adipate with OHN 110 g KOH/kg with functionality 2.
II. Flame retardant, FR (halogen and phosphorous free) additives
Our FR additive is a multifunctional compound that brings excellent FR properties and passes ASTM E84 for class A and class B test methods.
Its functionalities instantly react with side-A (ISO) and produce either polyurethane or polyurea that bring improved mechanical properties to the foam. Under exothermic conditions, it liberates gases such as N2 and or CO2 that help in the blowing process. Therefore our additive has 4 different functionalities in one compound.
III. Light (UV/LED) curable materials.
Light curing (UV/LED/Visible) adhesives and coatings from SK Resins-USA can be widely used for various industrial applications such as bonding, sealing, masking, and coating of similar or dissimilar components and assemblies. Our light curable liquid products are one part, solvent-free, and cure in seconds and become solid when exposed to ultraviolet (UV/LED) or visible light sources.
In general, light curing adhesives and coatings consists of three major components: oligomer (resin), monomer and the photoinitiator. The photoinitiator is highly sensitive to light and triggers the curing process the moment it is exposed to light and generates reactive free radicals. This process is called initiation. The free radicals that are highly unstable, start cross-linking with oligomer and monomers in the system to form a solid surface. The monomer in the final cured surface plays a key role in the adhesion whereas the oligomer provides most of the post-cure mechanical properties such as hardness, tensile strength, elongation, elasticity, shrinkage, etc. The core chemical nature of our products are based on reactive acrylates or epoxy components.
Some unique properties such as heat transfer, color, hydrophobicity to the surface can be achieved by using special additives in the formulation. Although the light-curable adhesives and coatings bring all the properties that are possible by conventional adhesives and coatings, they also face a big challenge. They do not cure in areas where light can't penetrate (Shadowed area). SK Resins-USA has engineered and formulated special types of adhesives that cure in the presence of either moisture or heat as a secondary cure process.
Our technologists and their creative and technical expertise drive SK Resins-USA to develop exceptionally unique UV/LED/Visible light curing adhesive and coating products. Some features of our products include:
Multi-cure adhesives and coatings exclusively designed for bonding shadowed areas
Faster and deep-cure adhesives are designed to make sure that they cure in substrates that are partially or fully blocked UV wavelengths
LED (365, 395 or 405nm) curable adhesives are formulated to cure exclusively at higher wavelength as this produces very less heat
Visible light (400nm and above) curable adhesives are formulated to cure exclusively in normal light sources including sunlight
Since LED curing brings several benefits such as low exotherm, longer light life, instant on/off control without shutter mechanism, it is getting popular in light adhesives and coatings. LED equipment manufacturers are now offering higher output intensities with greater selections of wavelength options. Most of our adhesives and coatings are halogen-free.
SK Resins-USA has been developing technologies and formulations for light-curable adhesives and coatings for several years. We are experienced to formulate our products exclusively for specific wavelength lights or to meet our customers’ very specific property needs.
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The strength of SK Resins are our highly qualified technologists.
Most of them have doctorate degrees with more than 35 years of collective experience in the area of resins and formulations for light curable processes including cosmetic applications.
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