A kind of preparation method of rigid melamine foam with low density and high closed cell ratio

A closed-cell, low-density technology, applied in the field of foam materials, can solve the problems of poor thermal insulation performance and cannot meet the basic requirements of building thermal insulation materials, and achieve good thermal insulation effects, prevent cracking and collapse, and facilitate foaming.

Active Publication Date: 2021-01-05
HEFEI UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the melamine foam prepared by the prior art generally has an open cell rate of more than 95%, resulting in a foam with a water absorption rate greater than 100%, a thermal conductivity greater than 0.03W / m, and poor thermal insulation performance, which cannot meet the basic requirements of building thermal insulation materials.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] The operation steps of preparing the rigid melamine foam with low density and high closed cell ratio are as follows:

[0026] (1) Preparation of melamine resin prepolymer

[0027] (1.1) Add 100g of melamine, 71.4g of paraformaldehyde and 121.6g of distilled water in sequence in a three-neck flask, and completely dissolve into a clear reaction system solution at 80°C under stirring;

[0028] (1.2) Add 1g of hexamethylenetetramine to the clear reaction system solution, and continue the reaction at 80°C for 90 minutes;

[0029] (1.3) Add 2g of sodium tetraborate and lower the temperature to below 30°C to obtain the melamine resin prepolymer;

[0030] (1.4) Store at 25°C for 5 days until the viscosity of the melamine resin prepolymer reaches 15Pa·s;

[0031] (2) Preparation of rigid melamine foam with low density and high closed cell ratio

[0032] (2.1) Take 100g of melamine resin prepolymer, 5g of cyclohexane, 2g of simethicone and 0.8g of hydrochloric acid, mix and st...

Embodiment 2

[0036] The operation steps of preparing the rigid melamine foam with low density and high closed cell ratio are as follows:

[0037] (1) Preparation of melamine resin prepolymer

[0038] (1.1) Add 100g of melamine, 71.4g of paraformaldehyde and 121.6g of distilled water in sequence in a three-neck flask, and completely dissolve into a clear reaction system solution at 80°C under stirring;

[0039] (1.2) Add 1.5g of hexamethylenetetramine to the clear reaction system solution, and continue the reaction at 80°C for 105 minutes;

[0040] (1.3) Add 2g of sodium tetraborate and lower the temperature to below 30°C to obtain the melamine resin prepolymer;

[0041] (1.4) Place it at 25°C for 8 days, and start foaming when the viscosity of the melamine resin prepolymer reaches 40Pa·s;

[0042] (2) Preparation of rigid melamine foam with low density and high closed cell ratio

[0043] (2.1) Take 100g of melamine resin prepolymer, 3g of cyclohexane, 2g of n-hexane, 2g of hydroxyl sili...

Embodiment 3

[0047] The operation steps of preparing the rigid melamine foam with low density and high closed cell ratio are as follows:

[0048] (1) Preparation of melamine resin prepolymer

[0049] (1.1) Add 100g of melamine, 71.4g of paraformaldehyde and 121.6g of distilled water in sequence in a three-neck flask, and completely dissolve into a clear reaction system solution at 80°C under stirring;

[0050] (1.2) Add 1.5g of hexamethylenetetramine to the clear reaction system solution, and continue the reaction at 80°C for 110min;

[0051] (1.3) Add 2.5g of sodium tetraborate and lower the temperature to below 30°C to obtain the melamine resin prepolymer;

[0052] (1.4) Place it at 25°C for 6 days, and start foaming when the viscosity of the melamine resin prepolymer reaches 25Pa·s;

[0053] (2) Preparation of rigid melamine foam with low density and high closed cell ratio

[0054] (2.1) Take 100g of melamine resin prepolymer, 4g of n-hexane, 2.5g of dimethyl silicone oil and 2g of a...

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Abstract

The invention relates to a preparation method for hard melamine foam with low density and high percentage of close area. A liquid foaming agent is served as a foaming agent of the melamine foam; the foaming process is fast once the foaming agent reaches the boiling point, and meanwhile, the foam pores are easy to break and collapse, but the viscosity of the prepolymer used in the invention is 10-50Pa.s, so that the viscosity of foaming solution is higher, the melamine resin has a certain strength in the beginning and the foam pores can be effectively prevented from breaking and collapsing. Themelamine resin adopted by the invention is prepared from melamine and paraformaldehyde and has a certain self-emulsifying capacity; the foaming solution is uniformly dispersed through strong mechanical stirring during the process of preparing the melamine foam and no surfactant is required; percentage of close area of the melamine foam is above 90%, heat conductivity coefficient is below 0.028W / m.K, compression strength is above 280kPa, water absorption is below 20%, density is below 50kg / m3 and oxygen index is above 36%.

Description

technical field [0001] The invention belongs to the technical field of foam materials, in particular to a method for preparing rigid melamine foam with low density and high closed cell ratio. Background technique [0002] Melamine foam plastic is a foam plastic material with low density and excellent properties of flame retardancy, heat resistance, sound absorption, heat preservation and self-extinguishing when away from fire. It is especially suitable for use in environments requiring flame retardancy and heat preservation. Flame retardancy and heat resistance are the most prominent properties of melamine foam. The decomposition temperature of melamine foam can reach about 400°C. As the temperature continues to rise, melamine foam begins to decompose, and the decomposition produces a large amount of N. 2 and CO 2 , At the same time, the flame is self-extinguishing because the dense carbon layer formed on the surface of the foam can isolate oxygen. This feature is a huge a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L61/28C08J9/14C08G12/32
CPCC08G12/32C08J9/141C08J2205/052C08J2205/10C08J2361/28
Inventor 马海红宋聪强李春晖徐卫兵周正发任凤梅
Owner HEFEI UNIV OF TECH
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