More and more, manufacturers are demanding bio-sourced raw materials to help their customers achieve their sustainability goals. In the service of these goals, manufacturers must focus on raw materials that are safer and derived from renewable resources. Sustainability helps manufacturers and their customers achieve a triple bottom line based on profitability, greater social responsibility, and improved environmental conditions via a reduced CO2 footprint.
Originally published on PR Web
Gantrade is pleased to announce its new European entity, Gantrade Europe BVBA. The office is now fully operational and is based at the group’s Mechelen offices in Belgium.
Polyurethanes are a special class of segmented block copolymers, consisting of alternating sequences of soft and hard segments. The soft segment is generally based on polyether or polyester polyols with glass transitions (Tg) well below room temperature, while the hard segment is composed of a diisocyanate and chain extender. The hard segment is often crystalline.
All polyol classes used in polyurethanes have a set of unique attributes that make them useful as the soft-segment in specific polyurethane elastomer applications. Selecting the best polyol for a specific formula can be the difference between making a high-quality product or one that’s low-performing. The key for proper material selection is a good understanding of the inherent characteristics of each polyol chemistry.
Polyurethanes based on polyester polyols, in general, exhibit higher tensile and tear properties, abrasion resistance, thermal stability, chemical resistance and weathering performance compared to polyether-based polyurethanes. They are preferred in the most demanding environments and applications. However, there is one weak point of polyester based polyurethanes. They are much more susceptible to hydrolysis compare with polyethers in polyurethanes. A part made of polyester based polyurethanes can gradually lose properties in a humid environment or water emersion.
2-Methyl-1,3-propanediol (MPO) based polyester polyols largely overcomes this deficiency due to the steric shielding of the ester linkage by the pendant methyl group on MPO, and greater hydrophobicity. MPOis an ideal diol intermediate for polyester polyols used in polyurethane elastomers (PURs). This is because MPOs unique structure enhances hydrolytic stability, affords liquid polyester polyols that are easier to handle, and demonstrates excellent compatibility in formulations.
The two major families of polyether polyols are polytetramethylene ether glycols (PTMEG) and polypropylene glycols (PPG). PTMEG is the premier polyol used in high-performance polyurethane elastomers. PTMEG-based polyurethanes exhibit superior resistance to hydrolytic cleavage, good mechanical property retention at low temperature, high resiliency, good processing characteristics, and excellent mechanical and dynamic properties. Strain-induced crystallization of the PTMEG soft segments, exact di-functionality, and low acid values are all contributing factors to the good mechanical properties of the associated polyurethane elastomers. PPG polyols have excellent hydrolysis resistance and low temperature properties as well. However, when compared to PTMEG polyols, the PPG polyols have lower mechanical properties and are more prone to thermo-oxidative degradation.
Adipic acid dihydrazide (ADH) is an effective crosslinking agent, curative and hardener. It is the most common dihydrazide crosslinking agent within a series of dihydrazides such as sebacic dihydrazide (SDH) and isophthalic dihydrazide (IDH). ADH’s has a melting point of 180 °C and a molecular weight of 174; both are lower than the alternative dihydrazides SDH and IDH.
The terminology, surfactant is a connected word, appropriately derived from surface-active agent. While used in an extensive range of industries, this blog post will focus on the use of surfactants in the CASE industry segment, where our products are applied in emulsion polymerizations and as stabilizers, dispersants, wetting agents and foam modifiers. The main functions of surfactants in water-based CASE applications are to emulsify water-insoluble, hydrophobic monomers to facilitate polymerizations in anemulsion state, and to stabilized suspensions of the resulting synthetic polymers so they can be stored, formulated and subjected to shear forces.
Vinyl acrylic binders and resins are economical products that find extensive usage in interior architectural paints and caulks, adhesives and sealants, paper and textile binders, paper saturants, engineered fabrics, and pigment dispersions. With the unlimited variability in monomer options and copolymer ratios, vinyl acetate-acrylic copolymer binders allow the design of products with a wide spectrum of cost and performance profiles. The role of the binder resin is to bind the pigments into a tough, continuous film and to promote the adhesion to the substrate surface while resisting wear and blistering etc. Vinyl acetate monomer achieves cohesive strength in a binder at a low cost, while acrylic monomers like butyl and 2-ethylhexyl acrylates enhance the performance of copolymers by improving flexibility, water resistance, adhesion, scrub, and stain resistance and outdoor weathering.
The leading crosslinking technology for acrylic emulsion polymers is ambient temperature crosslinking chemistry based on diacetone acrylamide (DAAM) and adipic acid dihydrazide (ADH) monomers. This technology, known as “keto-hydrazide crosslinking,” involves the direct reaction of the pendant ketone moiety on the DAAM-acrylic polymer segment with the hydrazide moiety of the ADH, with the evaporation of water in the film-forming process.
The highest adoption of this ambient temperature, self-crosslinking technology has been in high-durability paints and coatings for architecture, wood and concrete surfaces, and more. The DAAM/ADH pair is also used in crosslinkable sizing agents, thickeners, adhesives, and sealants.
