Novel Carbamylmethylated Melamine Polyols in Rigid Water-Blown Urethane Foams
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Abstract:
American Cyanamid Company has developed a novel, high functional carbamylmethylated melamine polyol named CYUNK™ HPC polyol. The reactivity of CYUNK™ HPC polyol was studied and compared with that of an aromatic amine polyol (Pluracol® 824 polyol) and a sucrose-based polyol (Voranol® 360 polyol). A combination of the CYUNK™ HPC polyol and aromatic amine polyol was used for the preparation of rigid urethane foams. Water, CFC-11A and a mixture of CFC-11A and water (50/50) were used as the blowing agents. The k-factor of the foams containing CYUNK™ HPC was good: 0.022 W/mK for the water-blown system, 0.018 for the foam blown with a mixture of CFC-11A and water, and 0.015 for the CFC-11A blown foam. In all cases, retention of the k-factor with ageing (at room temperature and 70°C) was better for foams containing CYLINK™ HPC than for the control foams. Photomicrographs of the cell structure showed that the cell size of the foams containing CYLINK™ HPC polyol was smaller than that of the control foams. The presence of CYLINK™ HPC polyol decreased the combustibility of the water-blown rigid urethane foams. This effect was very significant in the case of foams containing sucrose-based polyol. The residue after burning of the reference foam without flame retardant was 26%, and with flame retardant (10 pbw) 48%. The residue after burning of the foam containing 30 pbw of CYUNK™ HPC polyol without flame retardant was 76%. CYUNK™ HPC polyol can thus be classified as a reactive flame retardant ** . The study also included the effect of surfactant concentration and isocyanate index on the properties of water-blown rigid urethane foams containing CYUNK™ HPC polyol.Keywords:
Blowing agent
A flame-retardant rigid polyurethane foam was prepared from a flame-retardant polyether polyol,which was made of aromatic alcohol,aliphatic alcohol and bromal,compounded with solid and liquid flame retarders.Effects of the type of raw materials and retarders,blowing agent,and isocyanate fraction on flame-retardant performance of the rigid PU foam were investigated.The rigid PU foam pos- sessed a compressive strength of 270 kPa and an oxygen index of 29%,which satisfied the Chinese na- tional standard of flame-retardant B_2 grade.
Blowing agent
Isocyanate
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With the polyols,isocyanates,foaming agent and additive as raw material,adding a halogen-containing structure type flame retardant polyether polyol,flame-retardant rigid polyurethane foam(RPUF)was prepared.The effects of flame retardant polyol and the amount of foaming agent water on the flame retardant properties of RPUF were investigated.The results showed that the flame retardant polyether polyols can significantly improve the flame retardant properties of RPUF.Oxygen index increased as the amount increased,the foaming agent in an amount of water directly affects the density,mechanical properties and flame retardant properties of the RPUF.
Blowing agent
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Ammonium polyphosphate
Cone calorimeter
Limiting oxygen index
Epoxidized soybean oil
Thermogravimetric analysis
Ammonium phosphate
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Thermally resistant polyurethane foams containing 1,3,5-triazine ring were modified with additive flame retardants. It has been found that addition of melamine, melamine polyphosphate, or isocyanurate at the foaming step resulted in reduction of foam flammability. The physical properties of flame-retardant modified foams were compared with those of non-modified foams. The obtained modified foams showed oxygen index 22.2–24.2 and were highly thermally resistant even at long lasting 200℃ temperature exposure.
Blowing agent
Triazine
Polyphosphate
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This article raised the issue of studies on the use of new bio-polyol based on white mustard seed oil and 2,2'-thiodiethanol (3-thiapentane-1,5-diol) for the synthesis of rigid polyurethane/polyisocyanurate (RPU/PIR) foams. For this purpose, new formulations of polyurethane materials were prepared. Formulations contained bio-polyol content from 0 to 0.4 chemical equivalents of hydroxyl groups. An industrial flame retardant, tri(2-chloro-1-methylethyl) phosphate (Antiblaze TCMP), was added to half of the formulations. Basic foaming process parameters and functional properties, such as apparent density, compressive strength, brittleness, absorbability and water absorption, aging resistance, thermal conductivity coefficient λ, structure of materials, and flammability were examined. The susceptibility of the foams to biodegradation in soil was also examined. The increase in the bio-polyol content caused a slight increase in processing times. Also, it was noted that the use of bio-polyol had a positive effect on the functional properties of obtained RPU/PIR foams. Foams modified by bio-polyol based on mustard seed oil showed lower apparent density, brittleness, compressive strength, and absorbability and water absorption, as well as thermal conductivity, compared to the reference (unmodified) foams. Furthermore, the obtained materials were more resistant to aging and more susceptible to biodegradation.
Blowing agent
Brittleness
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Polyurethanes can be used in many applications by modifying their properties via facile methods. Most of the polyurethanes currently used for industrial applications originated from petrochemical-based chemicals. There is a growing demand in industries to use renewable resources for polyurethanes. Vegetable oil-based polyurethanes have shown properties comparable to that of petroleum-based polyurethanes. In this research, sunflower oil was used as a renewable resource for polyurethanes. Rigid polyurethane foams were prepared using sunflower-based polyols. The polyols were synthesized via epoxidation followed by a ring-opening reaction. Epoxy number, hydroxyl number, viscosity, and spectroscopy characterizations confirm the synthesis of bio-polyol. One of the major issues in polyurethanes is their high flammability which was reduced by using flame-retardants. Two flame-retardants using melamine and diphenylphosphinic acid (DPPMA) and a phosphorous‐nitrogen intumescent flame‐retardant (2,2‐diethyl‐1,3‐propanediol phosphoryl melamine, DPPM) were synthesized and used in bio-based polyurethanes. as used as an additive flame retardant. The foams with DPPMA and DPPM showed high closed cell content ( >90%) with a high compression strength of 217 kPa and 208 kPa, respectively. The microstructure analysis of the foams using scanning electron microscopy revealed an even distribution of the pore size. The addition of DPPMA and DPPM in polyurethane foams results in the formation of a protective char layer during the flammability test and reduces the weight loss from 43% to 2.5% and 1.4% and burning time from 70 seconds to 6 seconds and 4.5 seconds, respectively. Our research suggests that sunflower oil could be a potential candidate for the polyurethane industries and DPPMA and DPPM can be used as an effective flame-retardant in these bio-based polyurethane foams.
Blowing agent
Intumescent
Vegetable oil
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A novel bio-based polyol was synthesized using corn oil and 2-mercaptoethanol via thiol-ene reaction as an alternative to petroleum-based polyol for the synthesis of polyurethane foams. The polyol was analyzed using wet chemical techniques to obtain hydroxyl number and viscosity. Infrared spectroscopy and gel permeation chromatography were used to confirm the structural properties of the foams. Flame-retardant polyurethane foams were prepared by the addition of different concentrations of dimethyl methyl phosphonate (DMMP) in final foam composition. The effect of DMMP on the thermo-mechanical properties of the polyurethane foams was analyzed. The TGA analysis showed improved stability of the final char with addition of DMMP in the foams. All the foams maintained a well-defined cellular structure and over 95% of closed cell content. The horizontal burning test showed reduced burning time and weight loss from 115 s and 38 wt.% for the neat foams, to 3.5 s and 5.5 wt.% for DMMP-containing foams (1.94 wt.% P). The combustion test using cone calorimeter showed a considerable reduction in heat release rate and total heat release. Thus, our study shows that corn-oil based polyol can be used to produce renewable polyol for industrially producible rigid polyurethane foams. The addition of a small amount of DMMP could result in a significant reduction in the flame-retardant properties of the polyurethane foams.
Cone calorimeter
Flame test
Gel permeation chromatography
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Flame retarding spraying rigid polyurethane foam(RPUF) was prepared by one-step process using new flame retarding polyether polyol,common polyether polyol,polyisocyanate,foaming stabilizer,catalyst,crosslinking agent,blowing agent and fire retardant. The effects of new flame retarding polyether polyol,catalyst,blowing agent,crosslinking agent,and fire retardant on the RPUF were discussed. Results showed that the performances of RPUF were best when the contents of new flame retarding polyether polyol,triethylenediamine as catalyst,trimerization catalyst,foaming agent,crosslinking agent and fire retardant,based on 100 parts by weight of the polyol,were 25,4,2,28,3 and 25 parts by weight,respectively.
Blowing agent
Stabilizer (aeronautics)
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The synthesis of new triazinic polyols by oxyalkylation with the propyleneoxide of some well known condensation products derived from melamine (2,4,6-triamino-1,3,5-triazine), a heteroaromatic chain initiator, has been studied. By using the synthesized aromatic triazinic polyols in conventional foaming processes, rigid polyurethane foams with excellent physico-mechanical properties and inherent flame retardancy are obtained, better than those of rigid polyurethane foams derived from conventional aliphatic polyols based on sucrose. A new additive flame retardant with a similar heteroaromatic triazinic structure (1, 3, 5-trichlormethylisocyanurate) was also successfully evaluated. The non expensive and accessible raw materials, the facility of the reactions involved in this kind of synthesis, make the studied method very attractive from technological points of view.
Triazine
Blowing agent
Melamine resin
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