Viscous thermoset liquids

The technique also measures the modulus (stiffness) and damping (energy dissipation) properties of materials as they are deformed under periodic stress. Such measurements provide quantitative and qualitative information about the performance of the materials. The technique can be used to evaluate elastomers, viscous thermoset liquids, composite coatings, and adhesives, and materials that exhibit time, frequency, and temperature effects or mechanical properties because of their viscoelastic behaviour. 

Polyester Resins. Reinforced polyester resins are thermosets based on unsaturated polyesters from glycols and dibasic acids, either or both of which contain reactive double bonds. The ratio of saturated to unsaturated components controls the degree of cross-linking and thus the rigidity of the product (see POLYESTERS, unsaturated). Typically, the glycols and acids are esterified until a viscous liquid results, to which an inhibitor is added to prevent premature gelation. Addition of the monomer, usually styrene, reduces the viscosity to an easily workable level. 

The claimed compound of the invention is produced by the reaction of epichloro-hydrin and bisphenol A and was well known in the art and was also known to be useful in the preparation of thermosetting epoxy resins. The claim preamble As a manufacture..., is equivalent to saying As a product of manufacture..., which in turn means that these two claims are compound claims. Although the compound was well known in the literature, it was reported in the context where it made up to 70% to 90% of a complex liquid mixture. According to the applicant s patent application specification, no method had been described that would allow the production of pure 2,2-bis-[(4)-2,3-epoxypropoxyphenyl]propane directly from a reaction mixture. Prior attempts to recover the product of the reaction resulted in, at best, a viscous liquid that adversely affected the usefulness of the product. In contrast to the prior art, applicant s methods resulted in material of sufficient purity that the compound was isolated as a free-flowing, crystalline powder. This material could be easily handled and allegedly could be used to prepare epoxy resins equal or superior to the liquid material prepared previously. 

So far, it would seem that only thermosetting resins are suitable for reinforcement with continuous fibres. Historically, this is a logical situation, since impregnating is easiest with a not too highly viscous liquid, such as a resin, which is still a low-molecular substance during impregnation. Molten thermoplastics, on the contrary,... 

CNC MEL DF 50 is a viscous, water clear liquid thermosetting resin which is soluble in water at any concentration. The product is fully compatible with other thermosetting resins, organic and inorganic catalysts, synthetic softeners and also thermoplastic materials. 

Another way to sort polymers is based on their properties when heated. Thermoplastie polymers become a viscous liquid when heated but thermoset polymers react into crosslinked solids... 

Thermoset polymers are those whose precursors are heated to an appropriate temperature for a short time, so that tli wilt flow as a viscous liquid a diemkal aoss-linldiig reaction then causes the liquid to solidify U> form an infu le mass. The precursor materials nu be of low molecular weight some precursors, after mixing, will flow and cross-link at room temperature. 

The transitions between the three states occur at well-defined temperatures. Plastics, elastomers, and viscous liquids can be changed into thermosets. They can be changed back to their original state if the cross-linking results from ionic bonds. This is also possible if reversible covalent cross-linking takes place. 

As thermosetting materials pol5unerize, changing from a viscous liquid to a shaped solid, the plastic parts often carry some history of their flow experiences preceding hardening. This history often adversely affects mechanical and electrical properties, dimensions, cosmetic appearance, and even the density of the finished parts. 

Thermosetting matrices nsnally employed in the field of composites appear, prior to application, in a more or less viscous liquid state. At this stage, they have not yet nndergone cross-linking and, in order to trigger this process, specific agents... 

Thermosets are mainly viscous liquid resins, presenting their own compounding requirements. Liquid mixing systems of varying degrees, from the most basic to highly sophisticated are used, depending on the type of resin, additives, and volume output required. 

---