Background technology
Current generally higher for the foam viscosity of resol used of phenolic resin foam lagging material, substantially at 6000~15000cps not etc., especially for the external-wall heat-insulation material resol used that foams, viscosity is more than 10000cps.Full-bodied resol has a lot of shortcomings in foam process, and as batch mixing difficulty, the row that flows in foaming process is poor, and expansion ratio is low etc., therefore need to reduce the viscosity of foamed phenolic resin.
Reducing the viscosity of resin has several different methods, 1., add solvent in resin, and as water etc.; 2., reduce level of response in resin building-up process.Method adds solvent in 1., can cause the foam of final foaming of poor quality, and as many in middle abscess, intensity is low etc.2. method reduces resin reaction degree, causes in resin expanded process thermal discharge large, and heartburn phenomenon appears in foam.
Summary of the invention
Object of the present invention is exactly to provide in a kind of solidification process thermal discharge little in order to overcome the defect that above-mentioned prior art exists, prepared phenol formaldehyde foam exquisiteness, the preparation method of the expandable phenolic resin that intensity is high.
Object of the present invention can be achieved through the following technical solutions:
A preparation method for expandable phenolic resin, adopts following steps:
(1) get the raw materials ready according to following component and weight part content:
Phenol 1000, paraformaldehyde 700-750, catalyzer 20-40, properties-correcting agent 40-80;
(2) phenol, paraformaldehyde, catalyzer are placed in to reactor, controlling temperature is 60~90 ℃, reacts 3 hours;
(3) temperature of reaction is controlled to 70 ℃, adds wherein properties-correcting agent, continue reaction 0.5h, cooling discharge prepares expandable phenolic resin.
Described paraformaldehyde is that massfraction is 96% paraformaldehyde.
Described catalyzer is ammoniacal liquor or triethylamine.
Described properties-correcting agent is carboxamide.
Reaction in step (2) is first to react 1h at 60 ℃, is then warming up to 90 ℃ of reaction 2h.
Compared with prior art, the present invention has adopted mole proportioning of higher phenol and formaldehyde, effectively reduces the content of methylol in resol, can reduce the release of heat in resin curing process; Before pyroreaction, there is one section of low-temp reaction, the addition reaction that low-temp reaction is synthesis phase, when resin is synthesized, addition reaction energy can be more abundant, and while not only making resin solidification, thermal discharge reduces, and more can reduce the content of resin Free-formaldehyde; In last resin, add carboxamide, formaldehyde reaction free in resin generates urea-formaldehyde resin, greatly reduces the content of formaldehyde in resin.The synthetic resin viscosity of the present invention can be at 3000~4000cps, and in solidification process, thermal discharge is little, prepared phenol formaldehyde foam exquisiteness, and intensity is high.
Embodiment
Below in conjunction with specific embodiment, the present invention is described in detail.
Embodiment 1
A preparation method for expandable phenolic resin, adopts following steps:
(1) processing compound:
Phenol: 1000g, 96% formaldehyde: 731g, catalyzer: 30g, properties-correcting agent: 60g, wherein, the properties-correcting agent of use is carboxamide, the catalyzer of use is ammoniacal liquor;
(2) phenol, paraformaldehyde, catalyzer are placed in to reactor, controlling temperature is 60 ℃, reacts 1 hour, then temperature is elevated to 90 ℃, continues reaction 2 hours;
(3) temperature of reaction is controlled to 70 ℃, add wherein properties-correcting agent carboxamide, continue reaction 0.5h, cooling discharge prepares expandable phenolic resin, the resol preparing is detected, and its detected result is as follows: VIS=3200cps, NV=82.5%, GT=60sec, FF=0.7%.Can find out, in the expandable phenolic resin solidification process preparing, thermal discharge is little, prepared phenol formaldehyde foam exquisiteness, and intensity is high.
Embodiment 2
A preparation method for expandable phenolic resin, adopts following steps:
(1) get the raw materials ready according to following component and weight part content:
Paraformaldehyde paraformaldehyde 700, catalyst of triethylamine 20, properties-correcting agent carboxamide 40 that phenol 1000, massfraction are 96%;
(2) phenol, paraformaldehyde, catalyzer are placed in to reactor, react for first reacting 1h at 60 ℃, be then warming up to 90 ℃ of reaction 2h;
(3) temperature of reaction is controlled to 70 ℃, adds wherein properties-correcting agent, continue reaction 0.5h, cooling discharge prepares expandable phenolic resin.
Embodiment 3
A preparation method for expandable phenolic resin, adopts following steps:
(1) get the raw materials ready according to following component and weight part content:
Paraformaldehyde 750, catalyst ammonia water 40, properties-correcting agent carboxamide 80 that phenol 1000, massfraction are 96%;
(2) phenol, paraformaldehyde, catalyzer are placed in to reactor, react for first reacting 1h at 60 ℃, be then warming up to 90 ℃ of reaction 2h;
(3) temperature of reaction is controlled to 70 ℃, adds wherein properties-correcting agent, continue reaction 0.5h, cooling discharge prepares expandable phenolic resin.
Because the present invention has adopted mole proportioning of higher phenol and formaldehyde, effectively reduce the content of methylol in resol, can reduce the release of heat in resin curing process; Before pyroreaction, there is one section of low-temp reaction, the addition reaction that low-temp reaction is synthesis phase, when resin is synthesized, addition reaction energy can be more abundant, and while not only making resin solidification, thermal discharge reduces, and more can reduce the content of resin Free-formaldehyde; In last resin, add carboxamide, formaldehyde reaction free in resin generates urea-formaldehyde resin, greatly reduces the content of formaldehyde in resin.