Liquid polyol polyester

The polyesters derived from AA and DEG, and from AA and PG are liquid at room temperature. The branched polyesters based on AA-DEG/TMP or AA-DEG/glycerol are also liquid. The polyesters derived from AA-EG, AA-D, AA-HD and AA-NPG are solid at room temperature. It is very interesting that some polyester polyols based on AA and a mixture of... 

The specialty class of polyols includes poly(butadiene) and polycarbonate polyols. The poly(butadiene) polyols most commonly used in urethane adhesives have functionalities from 1.8 to 2.3 and contain the three isomers (x, y and z) shown in Table 2. Newer variants of poly(butadiene) polyols include a 90% 1,2 product, as well as hydrogenated versions, which produce a saturated hydrocarbon chain [28]. Poly(butadiene) polyols have an all-hydrocarbon backbone, producing a relatively low surface energy material, outstanding moisture resistance, and low vapor transmission values. Aromatic polycarbonate polyols are solids at room temperature. Aliphatic polycarbonate polyols are viscous liquids and are used to obtain adhesion to polar substrates, yet these polyols have better hydrolysis properties than do most polyesters. 

J. Low molecular weight symmetrical polyester polyols may be liquids as a result of many chain ends that disrupt crystalline packing entirely. 

Most moisture-curing liquid adhesives utilize poly(oxypropylene) (PPG) polyols, as shown above. These raw materials produce among the lowest-viscosity prepolymers but may not have sufficient modulus at higher temperatures for some applications. A certain percentage of polyester polyols may also be utilized to boost performance, but these may cause a large increase in viscosity, and so they are more often used in conjunction with polyether polyols to provide a high-performance adhesive with workable viscosities. Poly(butadiene) polyols may be utilized for specific adhesion characteristics. 

Liquid polyester MDI prepolymer, 9% NCO Liquid polymeric MDI, 2.2 functionality Polyol component ... 

Determination of Polyols in Alkyd and Polyester Resins by Gas Liquid Chromatography , Rept No CCL-214, APG (1966)... 

In the prepolymer system, the diisocyanate and polyol (either a polyether or a polyester) are reacted to give a prepolymer which may be either a liquid or a waxy solid. The reactant ratios used ensure the prepolymer contains isocyanate groups at the chain ends. 

A direct esterification procedure by which a linear polyester diol can be modified with p-hydroxybenzoic acid (PHBA) was demonstrated. The products are oligomers in which phenolic end-groups appear to predominate. They are heterogeneous and are probably liquid-crystalline when 30 wt% or more of PHBA is incorporated. The procedure has the advantage that appears adaptable to large scale production but the disadvantages that the polyols are predominately phenolic and are contaminated with small amounts of phenol and unreacted PHBA. 

Preparation of Microcellular Foams. The major polyols for microcellular elastomers include aliphatic polyester diols having a molecular weight of about 1,000 to 3,000, and poly-epsilon-caprolactones. Poly(oxytetramethylene) glycols (PTMEG) can also be used. The polyisocyanates to be used for microcellular elastomers are TDI-prepolymers and liquid MDI, i.e., carbodiimide-modified MDI or urethane-modified MDI. Low-molecular-weight, active-hydrogen compounds such as chain extenders (difunctional compounds) and... 

A reactive liquid epoxide used as an organic solvent and surfactant intermediate its polymers can be used for polyester, polyurethane, and polyacrylic resins, polyether polyols, flame-retardants, etc. 

Representative PCL are the diols of MW of 2000-4000 daltons, used in hydrolytically stable PU elastomers. The diols used as starters are DEG, 1,4 butanediol and NPG. The melting point of PCL, of MW of 2000 daltons, is in the range of 40-60 °C and of MW of 1000 daltons in the range of 30-40 °C. If a polyfunctional polyol is used as a starter, polyfunctional PCL polyols are obtained. Thus, by polymerisation of CPL initiated by trimethylolpropane (reaction 8.32) a polyester triol is obtained and initiated by pentaerythritol, a polyester tetraol is formed. It is interesting that some low MW PCL triols with a MW of 300-900 daltons are liquid at room temperature (melting points in the range of 6-16 °C). The viscosities of PCL polyols, at 60 °C, are 40-1600 mPa-s, depending on the polyol structure. 

PET wastes, proved to be an excellent raw material for low cost aromatic polyester polyols. By transesterification with DEG and (or) propylene glycol or dipropyleneglycol (DPG), liquid, low viscosity and low functionality aromatic polyester polyols were obtained. Due to the low cost, DEG is the preferred glycol for transesterification (reaction 16.3) [4, 6-8, 12]. 

The process of PET glycolysis with DEG has several disadvantages the reaction products are viscous liquids with a tendency to solidification or even to be solid at room temperature, the reproducibility of the characteristics of the resulting polyester polyols are difficult to realise (poor consistency) and the products of transesterification are not compatible with the blowing agents (pentanes or hydrofluorocarbons) [4, 6]. 

PA is commercialised in large quantities (especially for use in plasticisers, such as dioctylphthalate and unsaturated polyesters), in high purity form. The aromatic polyester polyols based on PA, due to the purity of the raw materials, are colourless liquids and the process of fabrication, is very reproducible (good consistency). The polyester polyols based on PA and DEG are synthesised in two steps ... 

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