Background and overview[1]
With the improvement of people’s environmental awareness, halogen-free and low-toxic flame retardants have attracted much attention. At the same time, the scope of use of traditional halogen flame retardants has become smaller and smaller. Therefore, the development of environmentally friendly, healthy and harmless flame retardants has become an inevitable trend in the development of flame retardants in today’s society. Resorcinol phosphate oligomer (RDP) flame retardant is a halogen-free additive flame retardant. Because of its unique chemical structure and mechanical properties, it shows excellent thermal stability in polymers. Due to its strong flame retardant properties, it is widely used. Currently, the catalysts used for the transesterification reaction of resorcinol tetraphenyl diphosphate mainly include liquid acid or alkali catalysts, solid acid or alkali catalysts, and lipase. Compared with enzyme catalysts and liquid catalysts, solid catalysts, especially solid alkali catalysts, have the advantages of simple process, low environmental pollution, and easy recycling. However, the activity of solid alkali catalysts is still low, and the reaction time required to achieve a higher glycerol conversion rate is Too long; at the same time, the catalyst’s resistance to deactivation is not good enough.
Apply[1]
Resorcinol tetraphenyl diphosphate can be used to prepare a thermosetting cyanate ester resin composition, which includes the following ingredients: multifunctional cyanate ester, epoxy resin and flame retardant. The thermosetting cyanate ester resin composition further includes an inorganic filler. The thermosetting resin composition of the present invention is used to prepare resin sheets, resin composite metal copper foils, prepregs, laminates, copper-clad laminates, printed circuit boards, etc. The resin composition of the present invention has excellent heat resistance, moisture resistance, flame retardancy and low thermal expansion coefficient. The phosphorus flame retardant is selected from tris(2,6-dimethylphenyl)phosphine, resorcin bis[bis(2,6-dimethylphenyl)phosphate], resorcin tetrakis Phenyl diphosphate, etc.
Preparation[1]
Method 1: Preparation method of resorcinol tetraphenyl diphosphate, the steps are as follows: phenol and phosphorus oxychloride react under the conditions of catalyst and heating to generate triphenyl phosphate; triphenyl phosphate and Resorcinol carries out transesterification reaction under the conditions of catalyst, heating and reduced pressure to obtain resorcinol tetraphenyl diphosphate. The reaction temperature is 80-260°C; the catalyst, the first step The reaction uses a Lewis acidic catalyst; the second step of the reaction uses a Lewis acidic catalyst or an alkaline catalyst, and the dosage is 0.05% to 3% of the weight of phenol or resorcinol. The acidic catalyst is selected from: MgCl2, ZnCl2, AlCl3, TiCl4; the basic catalyst is selected from : NaOH, KOH, Na2CO3, K2CO3, sodium phenolate. The reaction time is short and the energy consumption is low; the total yield of the obtained product is greater than 92%, and it can reduce environmental pollution.
Method 2: A method for preparing resorcinol tetraphenyl diphosphate, which is achieved through the following steps:
(1) Preparation of solid catalyst
The standard process formula, temperature rise method and reaction time for the polymerization of macroporous styrene-based ion exchange resins well known in the industry are selected. The difference is: based on 100 parts of the total monomer weight, add 0.5-2 parts of 6-(2 , 2-dicyanovinyl)-N-(2-hydroxyethyl)-1,2,3,4-tetrahydroquinoline, add 0.01-0.1 part of 2-[[4-(2,2-di Cyanovinyl)-3-methylphenyl]ethylamino]ethyl-1,4-phthalate methyl ester as comonomer, add 0.01-0.05 parts of 2,4-diphenyl-4-methyl -1-Pentene antioxidant 4020 is a chain transfer agent. It generates polymerized white balls through polymerization reaction. After drying, extract the porogen and dry it for use. The solid catalyst can be obtained by carrying out the sulfonation reaction according to the well-known sulfonation process of macroporous cation exchange resin.
(2) Transesterification reaction
Add 100 parts of triphenyl phosphate and 20-60 parts of resorcinol into the reactor by weight; the amount of solid catalyst is 5-15 parts; the reaction temperature is 110-250°C; the reaction time is 5 -15 hours, then distilled and washed to obtain the resorcinol tetraphenyl diphosphate product.
Main reference materials
[1] CN201611172645.9 Preparation method of resorcinol tetraphenyl diphosphate
