High-density melamine foam and preparation method thereof

Abstract

The present invention discloses high-density melamine foam, which comprises the following raw materials; a primary polymer of waterborne melamine formaldehyde resin, solid methylol melamine, a polar solvent, a surfactant, a foaming agent, a curing agent and an additive. The present invention also discloses a preparing method of the high-density melamine foam, comprising the following steps: preparing a primary polymer of waterborne melamine formaldehyde resin; uniformly mixing the primary polymer of the waterborne melamine formaldehyde resin, the polar solvent, the surfactant and the additive to obtain a mixture A; uniformly mixing the mixture A with the solid methylol melamine to obtain a mixture B; uniformly mixing the mixture B with the foaming agent to obtain a mixture C; uniformly mixing the mixture C with the curing agent to obtain a mixture D; and carrying out microwave radiation, foaming, curing, drying and quenching on the mixture D in a microwave foaming device to obtain the high-density melamine foam. The melamine foam described in the present invention has high density and high strength performance.

We Claim: 
     
         1 . High-density melamine foam, characterized by comprising the following raw materials is by weight: 0-99 parts of primary polymer of waterborne melamine formaldehyde resin, 1-100 parts of solid methylol melamine, 0-43 parts of polar solvent, 0.5-5 parts of surfactant, 1-20 parts of foaming agent, 0.1-10 parts of curing agent and 0-10 parts of additive. 
     
     
         2 . The high-density melamine foam according to  claim 1 , characterized in that the high-density melamine foam comprises the following raw materials in parts by weight: 50-90 parts of primary polymer of waterborne melamine formaldehyde resin, 10-50 parts of solid methylol melamine, 0-10 parts of polar solvent, 1-3 parts of surfactant, 5-15 parts of foaming agent, 1-5 parts of curing agent, and 0-5 parts of additive. 
     
     
         3 . The high-density melamine foam according to claim characterized in that: the molar ratio of formaldehyde to melamine in the raw materials of preparing the primary polymer of the waterborne melamine formaldehyde resin is 6:1 to 1.1:1, and the solid content is 50% to 80% the solid methylol melamine is powder or particles of methylol melamine monomer or primary polymer, or partially etherified methylol melamine, or a mixture of the previous two materials; the polar solvent is water or alcohol with a boiling point of 40° C., to 120° C.; the surfactant is an anionic surfactant, a nonionic surfactant or a cationic surfactant with the functions of emulsification, dispersion and bubbling; the foaming agent is a physical foaming agent with a low boiling point or a chemical foaming agent which is easily decomposed/reacts with add to produce gas; the curing agent is organic acid or inorganic acid; and the additive one or more of a light stabilizer, a heat stabilizer, an antiager, a formaldehyde scavenger, a colorant and a filler. 
     
     
         4 . The high-density melamine foam according to  claim 3 , characterized in that the molar ratio of formaldehyde to melamine is 4:1 to 2:1, and the solid content is 70% to 80%; the solid methylol melamine is one or more of a monomer or primary polymer of solid trimethylol melamine, solid tetramethylol melamine, solid hexamethylol melamine, partially etherified methylol melamine and partially butylated methylol melamine; the polar solvent is desalted water or distilled water; the surfactant is one or more of aqueous or solvent-free alkyl sodium sulfanate or potassium salt, sodium alkyl benzene sulfonate or potassium salt, alkyl naphthalene sulfonate, alkyl sulfate sodium salt or potassium potassium salt, alkyl carboxylate, polyoxyethylene ether sulfate sodium salt or potassium salt, alkyl olefin sulfonate, polyoxyethylene ether, alkanolamide, amine oxide, a silicon surfactant and a fluorocarbon surfactant; the physical foaming agent is one or more of alkane, halohydrocarbon, alcohol, ether, ester and ketone with the low boiling point; the chemical foaming agent is one or more of carbonate or bicarbonate, azodicarbamide, isocyanate and ammonium chloride; the organic acid is one or more of acetic acid, propanoic acid, oxalic acid, citric acid, palmitic acid, benzoic acid, sulfamic acid and glutamic acid; and the inorganic acid is one or more of hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, sulfurous acid, pyrophosphoric acid and boric acid. 
     
     
         5 . A preparing method of the high-density melamine foam of any of  claims 1 , characterized by comprising the following steps:
 (1) Preparing a primary polymer of waterborne melamine formaldehyde resin;   (2) Uniformly mixing the primary polymer of the waterborne melamine formaldehyde resin, the polar solvent, the surfactant and the additive in a thermostatic mixing tank proportionally to obtain a mixture A;   3) Uniformly mixing the, mixture A with the solid methylol melamine in a thermostatic single screw extruder or twin-screw extruder proportionally to obtain a mixture B;   (4) Uniformly mixing the mixture B with the foaming agent in the twin-screw extruder proportionally to obtain a mixture C;   (5) Uniformly mixing the mixture C with the curing agent in a thermostatic high-speed mixer proportionally to obtain a mixture D;   (6) Carrying out microwave radiation, foaming, curing, drying and quenching on the mixture D in a microwave foaming device to obtain the high-density melamine foam.   
     
     
         6 . The preparing method of the high-density melamine cording to  claim 5 , characterized in that: the solid content of the mixture B in Step (3) is 70% to 99%. 
     
     
         7 . The preparing method of the high-density melamine foam according to  claim 5 , characterized in that: the mixing rotating speed of Steps (2), (3) and (4) is 100 r/min to 500 r/min; the mixing rotating speed of Step (5) is 500 r/min to 3000 r/min; the material temperature of the mixture A, the mixture B and the mixture C is 26° C. to 40° C.; the material temperature of the mixture D is 10° C. to 30° C.; and the microwave radiation power in Step (6) is 1 kW/kg to 10 kW/kg, the radiation foaming time is 1 min to 20 min, the drying temperature is 150° C. to 250° C., and the drying time is 10 min to 60 min.