CN111333902A

CN111333902A - Low-thermal-conductivity composite foam material and preparation method thereof

Info

Publication number: CN111333902A
Application number: CN202010267598.6A
Authority: CN
Inventors: 董会娜; 龚祥明; 姚栋嘉; 吕多军; 曹二伟; 王红伟; 张继承; 张东生
Original assignee: Gongyi Van Research Yihui Composite Material Co Ltd
Current assignee: Gongyi Van Research Yihui Composite Material Co Ltd
Priority date: 2020-04-08
Filing date: 2020-04-08
Publication date: 2020-06-26

Abstract

The invention discloses a low-thermal-conductivity composite foam material, which is prepared by uniformly mixing resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant in proportion, filling mixed slurry into a mold, molding and curing to obtain a resin-based foam matrix; uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, impregnating the silica sol into a resin-based foam matrix, and performing gelling treatment, aging and drying to obtain the low-thermal-conductivity composite foam material. According to the invention, through the addition of the hollow microspheres, the problems of low mechanical strength and poor toughness of the traditional aerogel are solved, the operability of the aerogel serving as a thermal insulation material in construction application is increased, and the mechanical property of the aerogel material is greatly improved. The low-thermal-conductivity composite foam material prepared by the invention has good thermal and sound insulation characteristics and mechanical properties, is simple in forming process and convenient to operate, and can be widely applied to the requirements of industries, buildings and aerospace on thermal insulation members.

Description

Low-thermal-conductivity composite foam material and preparation method thereof

Technical Field

The invention belongs to the technical field of preparation of foam materials, and particularly relates to a preparation method of a low-thermal-conductivity composite foam material.

Background

With the progress of society and the development of economy, the consumption of energy resources is greatly improved, the awareness of energy conservation and environmental protection of people is increased, and the heat insulation material has been paid more and more attention as high efficiency for reducing energy consumption and is widely applied to the fields of industry, building, aviation, aerospace and the like. The existing heat insulation material mainly comprises: ceramic fiber cotton board, glass fiber cotton board, rock wool cotton board, polystyrene foam plastic board, foaming cement, novel expanded perlite heat preservation system, polyphenyl granule heat preservation slurry and the like. With the further development of the technology, the technology of the heat insulation material is developing towards the direction of novel, high efficiency and environmental protection.

The silica aerogel is a continuous three-dimensional network structure formed by mutually polymerizing nano-scale particles, and the thermal conductivity efficiency, the convection heat transfer efficiency and the radiation heat transfer efficiency of the silica aerogel are effectively limited due to the special nano-scale micropores and a skeleton structure, so that the silica aerogel has very low thermal conductivity coefficient and is a solid material with the lowest thermal conductivity coefficient in the world at present. The material composition is inorganic matter, belongs to A-grade non-combustible material, and can replace the application of the existing organic heat-insulating material in the heat-insulating system of the industrial building. However, the pure aerogel has low mechanical strength and poor toughness, which leads to poor dimensional stability of the aerogel material, and limits the operability and application of the aerogel material in construction. Therefore, on the basis of keeping the high-temperature heat-insulating property of the silicon dioxide aerogel, how to improve the mechanical property of the aerogel material and realize the wide application of the aerogel material in the field of heat insulation and heat preservation is particularly necessary.

The resin-based composite material is one of the first-choice materials for developing the light high-strength composite material at present, the molding process is simple, the operation is convenient, and the resin-based composite foam material prepared by compounding the hollow microspheres has low density and good compression resistance. The resin-based composite foam and the aerogel are combined with each other, so that the prepared novel composite foam material has good heat insulation, sound insulation and mechanical properties, meets the operability of the composite foam material in construction, and is expected to be applied to industries such as industry and building in a large scale.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: overcomes the defects in the prior art and provides a low-thermal-conductivity foam material and a preparation method thereof.

The technical scheme adopted by the invention for solving the technical problem is as follows:

the low-thermal-conductivity composite foam material consists of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1: (0.1-15).

The aerogel is silicon dioxide aerogel.

The preparation method of the low-thermal-conductivity composite foam material is characterized by comprising the following specific steps of:

(1) resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant are mixed according to the mass part of 100: (15-60): (1-5): (2-10): (1-3): (1-2): (3-5): (5-25) uniformly mixing to obtain mixed slurry;

(2) filling the mixed slurry into a mould for molding, and curing to obtain a resin-based foam matrix;

(3) uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, wherein the molar ratio of the silicon source to the ethanol to the water to the catalyst is 1: (4-20): (2-10): (0.002-0.02);

(4) dipping the resin-based foam matrix obtained in the step (2) in the silica sol prepared in the step (3), and performing gelling treatment to obtain resin-based foam composite gel;

(5) aging the resin-based foam composite gel obtained in the step (4) at the temperature of 20-60 ℃ for 6-36 h;

(6) and drying the aged resin-based foam composite gel by using supercritical carbon dioxide to obtain the prepared low-thermal-conductivity composite foam material.

Preferably, the resin is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac epoxy resin and modified epoxy resin; the hollow microspheres are one or more of hollow glass microspheres, aluminum silicate hollow microspheres, borate hollow microspheres, glass hollow microspheres, alumina hollow microspheres, silicon dioxide hollow microspheres, ceramic hollow microspheres, zirconia hollow microspheres, fly ash floating beads, carbon hollow microspheres, phenolic aldehyde hollow microspheres or polystyrene hollow microspheres; the shell of the thermal expansion microsphere is made of thermoplastic material, and the interior of the thermal expansion microsphere is filled with a foaming agent; the curing agent is one or more of dicyandiamide and derivatives thereof, succinic acid hydrazide, adipic acid dihydrazide, isophthalic acid dihydrazide and p-hydroxybenzoic acid hydrazide; the accelerant is one or more of organic urea UR300, UR500, DMP-30, pyridine, liquid imidazole, 2-methyl-4-hexylimidazole, acetylacetone metal salt, benzoyl peroxide, benzyl dimethylamine, triethylamine and polyether amine; the coupling agent is one of KH550 and KH 560; the toughening agent is one or more of polysulfide rubber, liquid nitrile rubber, liquid acrylate rubber, liquid polybutadiene rubber, SBS, EVA, polyether, polysulfone and low molecular polyamide; the flame retardant is one or more of HY-50, AMP-30, DOPO, ammonium polyphosphate, isopropylated triphenyl phosphate, decabromodiphenyl ether, decabromodiphenylethane, aluminum hydroxide and magnesium hydroxide.

Preferably, the thermoplastic material is a dichloroethylene copolymer, an acrylonitrile copolymer or an acrylic acid copolymer, and the foaming agent is hydrocarbons such as isobutane or isopentane.

Preferably, in the step (1), the particle size of the hollow microsphere is 50-125 μm, and the particle size of the thermal expansion microsphere is 10-50 μm.

Preferably, in the step (2), the mixed slurry is molded by any one of compression molding, injection molding and calendaring molding; the curing temperature is 100-150 ℃.

Preferably, in the step (3), the silicon source is one or more than two of ethyl orthosilicate, methyl orthosilicate, butyl orthosilicate and isopropyl orthosilicate; the catalyst is an acidic catalyst or a basic catalyst.

Preferably, the catalyst is one or more of ammonia water, ammonium fluoride and sodium hydroxide.

Preferably, in the step (4), the gelling temperature is 20-60 ℃ and the time is 10-24 h.

The invention has the following positive beneficial effects:

the preparation method comprises the steps of compounding the thermal expansion microspheres and the hollow microspheres and then molding to obtain the foam board, wherein the internal pressure is generated when the thermal expansion microspheres are foamed, the surface of a foam matrix is smooth and flat in a specific mold, and meanwhile, the bonding force between the hollow microspheres and the thermal expansion microspheres is enhanced due to the foaming effect.

The resin-based foam matrix prepared by impregnating the thermal expansion microspheres with the silica sol can play a part of the role of a support body, prevent collapse of the aerogel network in the drying process and ensure uniform pores of the aerogel network in the obtained foam material.

According to the invention, the hollow microspheres and the thermal expansion microspheres are added into the resin-based foam matrix, the shells of the thermal expansion microspheres are made of thermoplastic materials, the foaming agent is filled in the expansion microspheres, and the foaming agent and the hollow microspheres are matched to remarkably reduce the density of the resin-based foam matrix. The porous characteristic of the thermal expansion microspheres after foaming can ensure that the obtained foam has certain thermal insulation and sound insulation characteristics, and the thermal insulation and heat preservation performance of the foam material can be maintained after the thermal expansion microspheres are compounded with the aerogel.

According to the invention, through the addition of the hollow microspheres, the problems of low mechanical strength and poor toughness of the traditional aerogel are solved, the maneuverability of the aerogel serving as a thermal insulation material in construction application is increased by the prepared composite foam material, and the mechanical property of the aerogel material is greatly improved.

The low-thermal-conductivity composite foam material prepared by the invention has good heat and sound insulation characteristics and mechanical properties, can be used for preparing foam materials of complex components, and is simple in forming process and convenient to operate.

The low-thermal conductivity composite foam material prepared by the invention can be widely applied to the requirements of industries, buildings and aerospace on heat insulation and heat preservation components.

The specific implementation mode is as follows:

the technical solutions of the present invention will be further described in detail and clearly in the following with reference to specific examples, but the scope of the present invention is not limited thereto.

Example 1:

the low-thermal-conductivity composite foam material consists of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1: 0.5, the aerogel is silicon dioxide aerogel.

(1) resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant are mixed according to the mass part of 100: 20: 2: 4: 2: 1: 3:5, uniformly mixing to obtain mixed slurry;

(3) uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, wherein the molar ratio of the silicon source to the ethanol to the water to the catalyst is 1: 5: 5: 0.003;

(5) aging the resin-based foam composite gel obtained in the step (4) at 30 ℃ for 32 hours;

In the step (1), the resin is bisphenol A epoxy resin, the hollow microspheres are hollow glass microspheres, the shells of the thermal expansion microspheres are thermoplastic materials, and the interior of the thermal expansion microspheres is filled with a foaming agent; the curing agent is dicyandiamide and derivatives thereof, the accelerator is organic urea UR300, the coupling agent is KH550, the toughening agent is polysulfide rubber, and the flame retardant is ammonium polyphosphate. Wherein the thermoplastic material is a dichloroethylene copolymer, and the foaming agent is isobutane.

In the step (1), the particle size of the cenosphere is 50 μm, and the particle size of the thermally expandable microspheres is 15 μm.

In the step (2), the mixed slurry is molded by press molding, and the curing temperature is 115 ℃.

In the step (3), the silicon source is tetraethoxysilane and the catalyst is ammonia water.

In step (4), the temperature of gelation was 25 ℃ and the time was 15 hours.

Example 2

The low-thermal-conductivity composite foam material consists of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1:1, the aerogel is silicon dioxide aerogel.

The preparation method of the low-thermal-conductivity composite foam material comprises the following specific steps:

(1) resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant are mixed according to the mass part of 100: 30: 5: 10: 3: 2: 5: 10 to obtain mixed slurry;

(3) uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, wherein the molar ratio of the silicon source to the ethanol to the water to the catalyst is 1: 10: 5: 0.004;

(5) aging the resin-based foam composite gel obtained in the step (4) at 50 ℃ for 30 h;

In the step (1), the resin is novolac epoxy resin, the hollow microspheres are aluminum silicate hollow microspheres, the shells of the thermal expansion microspheres are thermoplastic materials, and the foaming agents are filled in the thermal expansion microspheres; the curing agent is succinic acid hydrazide, the accelerator is liquid imidazole, the coupling agent is KH560, the toughening agent is liquid nitrile rubber, and the flame retardant is isopropylated triphenyl phosphate. Wherein the thermoplastic material is acrylonitrile copolymer, and the foaming agent is isopentane.

In the step (1), the particle size of the cenosphere is 70 μm, and the particle size of the thermally expandable microspheres is 25 μm.

In the step (2), the mixed slurry is molded by injection molding, and the curing temperature is 130 ℃.

In the step (3), the silicon source is methyl orthosilicate, and the catalyst is ammonium fluoride.

In the step (4), the gelling temperature is 35 ℃ and the time is 17 h.

Example 3

The low-thermal-conductivity composite foam material consists of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1: 5, the aerogel is silicon dioxide aerogel.

(1) resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant are mixed according to the mass part of 100: 40: 1: 4: 2: 2: 3: 20 to obtain mixed slurry;

(3) uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, wherein the molar ratio of the silicon source to the ethanol to the water to the catalyst is 1: 7: 9: 0.0015;

(5) aging the resin-based foam composite gel obtained in the step (4) for 35 hours at 25 ℃;

In the step (1), the resin is a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin, and the mass part ratio of the bisphenol A type epoxy resin to the bisphenol F type epoxy resin is 1: 1; the hollow microspheres are borate hollow microspheres, the shells of the thermal expansion microspheres are made of thermoplastic materials, and foaming agents are filled in the thermal expansion microspheres; the curing agent is a mixture of isophthalic acid dihydrazide and p-hydroxybenzoic acid hydrazide, and the mass part ratio of the isophthalic acid dihydrazide to the p-hydroxybenzoic acid hydrazide is 1: 2; the accelerator is 2-methyl-4-hexyl imidazole, the coupling agent is KH550, the toughening agent is liquid polybutadiene rubber, and the flame retardant is decabromodiphenylethane. Wherein the thermoplastic material is acrylic copolymer, and the foaming agent is isobutane.

In the step (1), the particle size of the cenosphere is 90 μm, and the particle size of the thermally expandable microspheres is 30 μm.

In the step (2), the mixed slurry is formed by calendering, and the curing temperature is 125 ℃.

In the step (3), the silicon source is isopropyl n-silicate and the catalyst is sodium hydroxide.

In the step (4), the temperature of gelation was 40 ℃ and the time was 20 hours.

Example 4

The low-thermal-conductivity composite foam material consists of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1: 8, the aerogel is silicon dioxide aerogel.

(1) resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant are mixed according to the mass part of 100: 50: 3: 5: 2: 1: 4: 8 to obtain mixed slurry;

(3) uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, wherein the molar ratio of the silicon source to the ethanol to the water to the catalyst is 1: 13: 7: 0.016;

(5) aging the resin-based foam composite gel obtained in the step (4) at 30 ℃ for 28 h;

In the step (1), the resin is a mixture of novolac epoxy resin and modified epoxy resin, and the mass part ratio of the novolac epoxy resin to the modified epoxy resin is 3: 5; the hollow microspheres are silicon dioxide hollow microspheres, the shells of the thermal expansion microspheres are made of thermoplastic materials, and foaming agents are filled in the thermal expansion microspheres; the curing agent is p-hydroxybenzoic acid hydrazide, the accelerator is acetylacetone metal salt, the coupling agent is KH550, the toughening agent is polyether, and the flame retardant is decabromodiphenylethane. Wherein the thermoplastic material is a dichloroethylene copolymer, and the foaming agent is isobutane.

In the step (1), the particle size of the cenosphere is 120 μm, and the particle size of the thermally expandable microspheres is 45 μm.

In the step (2), the mixed slurry is molded by compression molding, and the curing temperature is 140 ℃.

In step (4), the temperature of gelation was 55 ℃ for 14 hours.

Example 5

The low-thermal-conductivity composite foam material consists of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1: 10, the aerogel is silicon dioxide aerogel.

(1) resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant are mixed according to the mass part of 100: 55: 5: 10: 6: 2: 5: 8 to obtain mixed slurry;

(3) uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, wherein the molar ratio of the silicon source to the ethanol to the water to the catalyst is 1: 15: 5: 0.007;

(5) aging the resin-based foam composite gel obtained in the step (4) at 35 ℃ for 25 h;

In the step (1), the resin is bisphenol F type epoxy resin, the hollow microspheres are ceramic hollow microspheres, the shells of the thermal expansion microspheres are thermoplastic materials, and the interior of the thermal expansion microspheres is filled with a foaming agent; the curing agent is p-hydroxybenzoic acid hydrazide, the accelerator is benzyldimethylamine, the flexibilizer is low molecular polyamide, and the flame retardant is magnesium hydroxide. Wherein the thermoplastic material is acrylonitrile copolymer, and the foaming agent is isopentane.

In the step (1), the particle size of the cenosphere is 110 μm, and the particle size of the thermally expandable microspheres is 20 μm.

In the step (2), the mixed slurry is molded by injection molding, and the curing temperature is 135 ℃.

In the step (3), the silicon source is isopropyl n-silicate, and the catalyst is sodium hydroxide.

In the step (4), the gelling temperature is 35 ℃ and the time is 15 h.

Example 6

The low-thermal-conductivity composite foam material consists of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1: 12, the aerogel is silicon dioxide aerogel.

(1) resin, hollow microspheres, thermal expansion microspheres, a curing agent, an accelerant, a coupling agent, a toughening agent and a flame retardant are mixed according to the mass part of 100: 60: 4: 3: 5: 2: 3: 25 to obtain mixed slurry;

(3) uniformly mixing a silicon source, ethanol, water and a catalyst to obtain silica sol, wherein the molar ratio of the silicon source to the ethanol to the water to the catalyst is 1: 18: 3: 0.009;

(5) aging the resin-based foam composite gel obtained in the step (4) at 40 ℃ for 19 h;

In the step (1), the resin is bisphenol F type epoxy resin, the cenospheres are zirconia cenospheres, the shell of the thermal expansion microballoon is thermoplastic material, and the interior of the thermal expansion microballoon is filled with foaming agent; the curing agent is adipic dihydrazide, the accelerator is triethylamine, the coupling agent is KH560, the toughening agent is liquid polybutadiene rubber, and the flame retardant is decabromodiphenyl ether. Wherein the thermoplastic material is acrylic copolymer, and the foaming agent is isopentane.

In the step (1), the particle size of the cenosphere is 80 μm, and the particle size of the thermally expandable microspheres is 40 μm.

In the step (2), the mixed slurry is molded by calendering, and the curing temperature is 145 ℃.

In the step (4), the temperature of gelation was 50 ℃ and the time was 18 hours.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low thermal conductivity syntactic foam characterized by: the low-thermal-conductivity composite foam material is composed of a resin-based foam matrix and aerogel, wherein the mass part ratio of the resin-based foam matrix to the aerogel is 1: (0.1-15).

2. The low thermal conductivity composite foam of claim 1, wherein: the aerogel is silicon dioxide aerogel.

3. The method for preparing a low thermal conductivity syntactic foam of claim 2, comprising the specific steps of:

4. The method for preparing a low thermal conductivity composite foam material according to claim 3, wherein in the step (1), the resin is one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac epoxy resin, modified epoxy resin; the hollow microspheres are one or more of hollow glass microspheres, aluminum silicate hollow microspheres, borate hollow microspheres, glass hollow microspheres, alumina hollow microspheres, silicon dioxide hollow microspheres, ceramic hollow microspheres, zirconia hollow microspheres, fly ash floating beads, carbon hollow microspheres, phenolic aldehyde hollow microspheres or polystyrene hollow microspheres; the shell of the thermal expansion microsphere is made of thermoplastic material, and the interior of the thermal expansion microsphere is filled with a foaming agent; the curing agent is one or more of dicyandiamide and derivatives thereof, succinic acid hydrazide, adipic acid dihydrazide, isophthalic acid dihydrazide and p-hydroxybenzoic acid hydrazide; the accelerant is one or more of organic urea UR300, UR500, DMP-30, pyridine, liquid imidazole, 2-methyl-4-hexylimidazole, acetylacetone metal salt, benzoyl peroxide, benzyl dimethylamine, triethylamine and polyether amine; the coupling agent is one of KH550 and KH 560; the toughening agent is one or more of polysulfide rubber, liquid nitrile rubber, liquid acrylate rubber, liquid polybutadiene rubber, SBS, EVA, polyether, polysulfone and low molecular polyamide; the flame retardant is one or more of HY-50, AMP-30, DOPO, ammonium polyphosphate, isopropylated triphenyl phosphate, decabromodiphenyl ether, decabromodiphenylethane, aluminum hydroxide and magnesium hydroxide.

5. The method of claim 4, wherein the thermoplastic material is a dichloroethylene copolymer, an acrylonitrile copolymer or an acrylic copolymer, and the blowing agent is a hydrocarbon such as isobutane or isopentane.

6. The method for preparing a low thermal conductivity composite foam material according to claim 3, wherein in the step (1), the particle size of the cenospheres is 50-125 μm, and the particle size of the thermal expansion microspheres is 10-50 μm.

7. The method for preparing a low thermal conductivity composite foam material according to claim 3, wherein in the step (2), the mixed slurry is molded by any one of compression molding, injection molding and calendaring molding; the curing temperature is 100-150 ℃.

8. The method for preparing a low thermal conductivity composite foam material according to claim 3, wherein in step (3), the silicon source is one or more of ethyl orthosilicate, methyl orthosilicate, butyl orthosilicate and isopropyl orthosilicate; the catalyst is an acidic catalyst or a basic catalyst.

9. The method of claim 8, wherein the catalyst is one or more of ammonia, ammonium fluoride and sodium hydroxide.

10. The preparation method of the low thermal conductivity composite foam material according to claim 3, wherein in the step (4), the gelling temperature is 20-60 ℃ and the time is 10-24 h.