Polyurethane TuMaterialThat is, Jujing is a formate paint, which means that its coating film contains a considerable amountamountUrethane key coating. Polyurethane is removedIn addition to urethane bonds, there are many ester bonds,etherKey,ureakey,ure span>methylformateKey, 三JuyiCyanate ester bondsor unsaturated double bonds of fats and oils, etc. However, it is customary to still call it For polyurethane coating.
Main formula of polyurethane coating
Polyurethane resinUnlike polyacrylate, it is made of acrylateSingleTiJu合Multiple. PolyurethaneEsterResin is not made of urethane It is formed by the polymerization of monomers, but is composed of polyisocyanate esters (Mainly two differencesCyanate ester) and polyesterAlcohol AntiShouldMade, andAndThe process of combining them to form a polymer is neither condensation nor condensation. Aggregation. But introductioninbetween the two, said It is called stepwise polymerization or addition polymerization. In this reaction, active hydrogen in one molecule is transferred to another molecule span style=”font-family: Microsoft Yahei;letter-spacing: 0;font-size: 16px”>number of molecules,There are no by-products during the reaction process.
(1)idicyanoAcid ester
IsoCyanideThe chemical properties of acid estersSplash, containingoneone or more DifferentcyanoAcidEsterBasic, capablewithwith livelinessHydrogen compound reaction. Commonly used isocyanateCyanideThe acid ester is aromatic toluene diisoCyanideAcid ester (AbbreviationTDI), 二PhenylmethaneAlkaneEnergycyano Acid ester (abbreviationMDI), etc., aliphatic hexamethylene diisocyanoacidester(HDI)TwoPolyacid二 DifferentcyanoAcidEster（DDI), etc. .
(2)Hydroxy-containing compounds
As polyurethaneesterThe hydroxyl-containing components of the coating include: polyester, polyether span>, epoxy resin,SesameSesame oil and itsAddIndustrial products (oxidized polymerized oil, glycerinAlcohollysates), and hydroxyl-containing thermoplastic polymers (such as containing β-hydroxyl polypropyleneeneacidtree fat, etc.). It should be pointed outout, small molecular polyols can only be used as raw materials for making prepolymers or adducts, but notSingleUnique polyurethane double B in component paintGroupMin. Because small molecule alcohols are water-solublepropertymatter,Cannot be differentCyanideAcidesterMix component A; secondly,High water absorption can easily cause the paint film to turn white during film formation, and the molecules are too small, and the conjunctival time is too long, evenknotmembrane, the internal stress is also large.
Yahei;letter-spacing: 0;font-size: 16px”>The hydroxyl-containing components of the coating are: polyester, polyether, epoxy resin,薖Sesame oil and its contentsAddIndustrial products (oxidized polymerized oil, glycerinAlcohollysates), and hydroxyl-containing thermoplastic polymers (If it containsβ-hydroxyl polypropyleneeneacidTreeGrease, etc.). It should be pointed outout, small molecular polyols can only be used as raw materials for making prepolymers or adducts, but notSingleUnique polyurethane double B in component paintGroupMin. Because small molecule alcohols are water-solublepropertymatter,Cannot be differentCyanideAcidesterMix component A; secondly,High water absorption can easily cause the paint film to turn white during film formation, and the molecules are too small, and the conjunctival time is too long, evenknotmembrane, the internal stress is also large.
