Preparation And Application Of Synergistic Flame Retardant Polyols

Polyurethane foam insulation materials have excellent physical and chemical properties, so it is widely used in many fields. However, oxygen index of the materials unprocessed by flame retardant is only 16, so it is easy to burn. When the materials are put into use, potential threat of human life and property exsits, which limits some further extensive applications. The flame retardant treatment has become an important research topic. Nowdays, some flame retardants additive could significantly improve the flame retardancy of polyurethane foam materials, and had widely been used in the industry. However, they destroy part physical and mechanical properties of the foams. In addition, the flame retardants will migrate to the materials' surface over time, which cause the environmental pollution and further decrease many physical-mechanical performances of the materials. Researching and developing reactive flame retardants without influence on the physical and mechanical properties of the polyurethanes and lasting flame retardant effect is of great significance.In this paper, we designed and synthesized three types of reactive flame retardant polyols by one-pot reaction, and used the last two for the preparation of polyurethane foam. The content and conclusions are as follows:1. Mixed phosphates were obtained by the reaction of water and phosphorus pentoxide(P4O10). The phosphates reacted further with epichlorohydrin to form phosphoric ester based flame retardant polyols under the catalysis of cetyl trimethyl ammonium bromide(CTAB). The effect of epoxy chloropropane decreasing the acid value of the product was significant. As the dosage of epoxy chloropropane increased, the acid values of the polyols decreased, but the amount of free epichlorohydrin increased at the same time. The acid values of the flame retardant polyols increased with increasing molar ratios of P4O10 to H2 O. The acid values of the products firstly decreases and then increases as the increasing the dosage of catalyst CTAB. Reaction temperature from 130 ? to 160 ? caused the acid values of products firstly increase and then decrease. The product decomposition was obvious as temperature was higher than 130?.2. The reaction of triethyl phosphate with phosphorus pentoxide produced polyphosphate ester. The goal products, polyphosphate flame retardant polyols were obtained by the ester exchange of polyphosphate ester with pentaerythritol, and then grafted with epoxy chloropropane catalyzed by the transesterification catalyst 49101. Orthogonal test showed the amount of phosphorus pentoxide is the biggest impact factor among the dosages of the phosphorus pentoxide, epoxy chloropropane and CTAB and reacting time on the acid value of the products. The results suggested that the acid value of the product, 1.78 mg KOH/g was minimum when phosphorus pentoxide, epichlorohydrin, CTAB was 4g, 30 g and 0.8%, respectively and reacting time of 3h. The polyphosphate ester belonged flame retardant polyols of low hydroxyl values.3. PET polyols could be prepared by PET sheet plastics reacting with low molecular polyols. The PET based synergistic flame polyols were obtained by the reaction of PET polyols as starting raw materials with reacting flame retardants containing bromine and nitrogen, the epoxy chloropropane under the catalysis of quaternary ammonium salt. The effect of the flame retardant containing bromine, retardant containing nitrogen, epichlorohydrin and quaternary ammonium salt on the acid values of the products were investigated by orthogonal test. When the weight of flame retardants containing bromine was 10 g, the weight of epoxy chloropropane was 32 g, the weight of retardant containing nitrogen was 2g and the weight of quaternary ammonium salt was of 2% based on the mass of PET polyols, the acid value of the product with 0.76 mgKOH/g was the lowest.4. The rigid polyurethane foam materials were prepared by using the flame retardant polyols synthesized PET based flame retardant polyols and polyphosphate ester as raw materilas. The oxygen indexs of the materials had been over 24.5%, which suggested excellent flame retardant of the polyols. When the polyols and additive flame retardants tris-(1-chloro-2-propyl) phosphate(TCPP) were used in conjunction, the limit oxygen index of the prepared polyurethane foam materials could reach above 29.5%. But in a certain range, TCPP had little effect on the improvement of the oxygen index of polyurethane foam materials,and the synergistic effect is poor.