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Moisture-cure polyurethane binders for particulates are produced using a wide range of chemistries for both the polyol and isocyanate components, depending on the requirements of the final composite product. The “active” agent in the binder is the prepolymer, which may be composed of any variety of polyol and isocyanate reactants at a stoichiometry to achieve a “% free NCO, ” typically between 3-25%. The polyol component may be polyether, polyester, polybutadiene, or natural oil based. The isocyanate may be selected from the entire range of conventional chemistries, TDI, various isomers of pure MDI, polymeric MDI, and aliphatic types.Many critical physical properties of the final composite are dictated by the polyol and isocyanate choice, and by the molecular weight of the prepolymer. However, the natural viscosity of the prepolymer increases rapidly with increasing molecular weight and functionality. For instance, a simple prepolymer of polypropylene glycol polyether diol and MDI will have a viscosity of 1, 000-2, 000 cps at a free NCO in the 8-10% range. Increasing functionality through either polyol or isocyanate choice can result in prepolymer viscosities several multiples of these figures at the same free NCO range.Since many particulate bonding processes rely on mixing the particles with the moisture-cure binder at ambient temperature and humidity using relatively low-shear mixing equipment, binder viscosities over 1, 000 cps are problematic for uniform incorporation into the mix. The conventional resolution to this problem is to incorporate a non-reactive hydrocarbon diluent into the formulation at levels ranging from 10% to (in some cases) over 30%. Hydrocarbons of choice are typically naphthenic and aromatic process oils, which are relatively inexpensive and exhibit fairly high compatibility with the prepolymer, along with good viscosity depression characteristics.However, particularly at higher levels, the addition of hydrocarbon diluents creates other problems:• Incompatibility in the liquid phase• Incompatibility in the cured (solid) phase• Reduction of physical properties by plasticization or extension• Increase in VOC content• Problematic regulatory status (with aromatic oils in particular)In addition, the price of these types of hydrocarbons has been quite volatile in recent years, and the availability and consistency has been negatively affected by changes in refining processes and capacity. Given the limitations of current prepolymer and diluent technology, the “perfect” diluent would have the following characteristics:• Efficient viscosity depression• Compatibility with a wide range of polyol and isocyanate chemistries• No effect on final cured properties• No addition of VOCs• No regulatory problems• Ready availability• Low costOne diluent that could potentially meet all of these criteria is water. In fact, this transition has already been made in the coatings and adhesives industries that are going from solvent-soluble polymers to emulsions of the same types of polymer backbones.For more details & prices for PU Binder please email us at :info@arihantindia.in
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We are the manufacturers & suppliers of all kinds of Rubber infill material for Artificial grass. There are many kinds of Rubber infill materials like :Crumb Rubber: Crumb Rubber is derived from scrap car and truck tires that are ground up and recycled. Two types of crumb rubber infill exist: Ambient and Cryogenic. Together these make up the most widely used infill in the synthetic sports field and landscape market. Crumb rubber infill is substantially metal free, and, according to the STC Guidelines for Crumb Rubber Infill, should not contain liberated fiber in an amount that exceeds .01% of the total weight of crumb rubber, or .6 lbs. per ton.Coated Rubber Infill: Both ambient and cryogenic rubber can be coated with colorants, sealers, or anti-microbial substances if desired. Coated rubber provides additional aesthetic appeal, reduction of dust by products during the manufacturing process and complete encapsulation of the rubber particle.EPDM Infill: EPDM (Ethylene Propylene Diene Monomer) is a polymer elastomer with high resistance to abrasion and wear and will not change its solid form under high temperatures. Typical EPDM colors are green and tan. EPDM has proven its durability as an infill product in all types of climates. Its excellent elasticity properties and resistance to atmospheric and chemical agents provide a stable, high performance infill product.For further details & lowest price offer on Rubber infill material please contact us at:Email : info@arihantindia.inTel : +91-9899447115
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