Preparation method of modified epoxy resin hydrophobic emulsion of thermal insulation material

Abstract

The invention provides a preparation method of a modified epoxy resin hydrophobic emulsion of a thermal insulation material, which comprises the following steps: in a nitrogen atmosphere, adding a polymeric monomer, a cationic surfactant and deionized water into a container, and carrying out a pre-emulsification reaction; slowly dropwise adding an initiator, and continuously reacting to obtain an emulsion A; in a nitrogen atmosphere, adding a polymeric monomer, a cationic surfactant and deionized water into the container, and carrying out a pre-emulsification reaction to obtain an emulsion B; slowly dropwise adding the emulsion B and an initiator into the emulsion A, and reacting to obtain the cationic emulsion. The preparation method comprises the following steps: mixing the cationic emulsion with an ethanol-water solvent, uniformly stirring, adding sepiolite powder, uniformly stirring, standing for 20-24 hours, adding epoxy resin powder, and uniformly stirring to obtain the hydrophobic emulsion.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal insulation materials, and particularly relates to a preparation method of a modified epoxy resin hydrophobic emulsion for thermal insulation materials. Background Art

[0002] The thermal insulation and heat preservation materials used in domestic and foreign industries and buildings mainly include: porous materials such as rock wool, glass wool, high-performance fibers, aerogels, organic foams, and asbestos. However, porous materials are prone to water absorption, and the water content has a significant impact on the heat preservation effect, which will seriously reduce the heat preservation effect of the materials. Immersing the thermal insulation material in a hydrophobizing agent solution for modification is a common method to improve the hydrophobicity of the thermal insulation material. At present, most of the hydrophobizing agents on the market are mainly silicon-based materials, which have the problems of high cost and poor hydrophobic effect. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a modified epoxy resin hydrophobic emulsion for thermal insulation materials, which can effectively improve the hydrophobicity of thermal insulation materials and has low cost.

[0004] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is:

[0005] A preparation method of a modified epoxy resin hydrophobic emulsion for thermal insulation materials, comprising the following steps:

[0006] A. Under a nitrogen atmosphere, add polymerization monomers, cationic surfactants, and deionized water into a container for pre-emulsification reaction; then slowly dropwise add an initiator and continue the reaction to obtain emulsion A;

[0007] B. Under a nitrogen atmosphere, add polymerization monomers, cationic surfactants, and deionized water into a container for pre-emulsification reaction to obtain emulsion B;

[0008] C. Slowly dropwise add emulsion B and the initiator into emulsion A together and react to obtain a cationic emulsion.

[0009] D. Mix the cationic emulsion with an ethanol-water solvent, stir evenly, add sepiolite powder, stir evenly, and let stand for 20-24 h, then add epoxy resin powder and stir evenly to obtain a hydrophobic emulsion.

[0010] Sepiolite is a layer-chain silicate mineral. In its structure, two layers of silicon-oxygen tetrahedrons sandwich a layer of magnesium-oxygen octahedrons to form a layered structure. Sepiolite contains zeolite pores and voids that run through the entire structure, so it has strong adsorption capacity. In this invention, a cationic emulsion is first used to conduct ion-exchange modification with sepiolite, adsorbing organic cations to replace the magnesium ions at the edge of the octahedral structure. At the same time, the hydrophobic alkyl chains wrap sepiolite, preventing water molecules from entering the interior of sepiolite, turning the hydrophilic clay surface into a lipophilic one, improving the dispersibility of sepiolite in the organic phase, strengthening the interfacial adhesion between sepiolite and the thermal insulation material, and enhancing the physical and mechanical properties of the material. After sepiolite is fully soaked and modified in the emulsion, it is added to epoxy resin. The compatibility between the modified sepiolite and the epoxy resin matrix increases, and a super-hydrophobic layer is prepared.

[0011] In steps A and B of the present invention, the solid-liquid mass ratio of the reaction raw materials is 1:5, and among them, the cationic surfactant accounts for 20% of the mass of the solid raw materials.

[0012] The polymerization monomers in step A of the present invention are styrene, allyl caproate, and dimethyldodecylallylammonium chloride, and the mass ratio is 5:5:1; the polymerization monomers in step B are butyl acrylate, butyl methacrylate, and dodecyl acrylate, and the mass ratio is 5:4:2.

[0013] In step D of the present invention, the mass ratio of the raw materials is: 25 - 35 parts of cationic emulsion, 50 parts of epoxy resin, 8 - 10 parts of sepiolite, 80 - 120 parts of ethanol, and 300 - 500 parts of deionized water.

[0014] Preferably, the volume ratio of ethanol to deionized water is 1:4, and the stability of the latex particles is the best.

[0015] The cationic surfactant in the present invention is a C12 - C22 alkyl quaternary ammonium salt type cationic surfactant.

[0016] Preferably, the cationic surfactant is cetyltrimethylammonium chloride.

[0017] The initiator in the present invention is azodiisobutyramidine hydrochloride.

[0018] The reaction conditions for pre-emulsification in the present invention: the temperature is room temperature, the rotation speed is 600 - 1000 rpm / min, and pre-emulsification is carried out for 30 min; the initiator is slowly added dropwise to the emulsion at 80 - 90 °C, and the heat preservation reaction is carried out for 2 - 3 h.

[0019] The particle size of the sepiolite powder in the present invention is 200 mesh.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. Styrene and allyl hexanoate are selected as the hard monomers in the present invention, and butyl acrylate, butyl methacrylate and dodecyl acrylate are used as the soft monomers. By strictly controlling the monomer ratio, the stability and dispersibility of the emulsion polymer can be effectively controlled; dimethyldodecylallylammonium chloride and cetyltrimethylammonium chloride are used as cationic monomers, which participate in the polymerization and introduce positive charges on the polymer chain segments, facilitating adsorption by sepiolite and being tightly wrapped; the initiator is a water-soluble azo initiator, and the decomposed free radicals carry positive charges, which are the same as the electric charges of the emulsion particles. After polymerization on the surface of the emulsion particles, it is beneficial to improve the stability of the composite cationic emulsion and form hydrophobic cationic emulsion particles with positive charges on the surface.

[0022] 2. Under the action of the cationic monomer and the initiator, a cationic emulsion with a core-shell structure was successfully synthesized by a two-step semi-continuous polymerization method, which has good thermal stability. The sepiolite modified by the latex particles has good compatibility and hydrophobicity with the epoxy resin matrix. Specific Embodiments

[0023] In order to more clearly and detailedly illustrate the objective technical solution of the present invention, the present invention will be further described through relevant embodiments below. The following embodiments are only for specifically illustrating the implementation method of the present invention and do not limit the protection scope of the present invention.

[0024] Example 1

[0025] A preparation method of a modified epoxy resin hydrophobic emulsion for thermal insulation materials, comprising the following steps:

[0026] A. Under a nitrogen atmosphere, add polymerization monomers, cationic surfactants and deionized water into a container for pre-emulsification reaction; then slowly dropwise add the initiator and continue the reaction to obtain emulsion A;

[0027] B. Under a nitrogen atmosphere, add polymerization monomers, cationic surfactants and deionized water into a container for pre-emulsification reaction to obtain emulsion B;

[0028] C. Slowly dropwise add emulsion B and the initiator together into emulsion A and react to obtain a cationic emulsion.

[0029] D. Mix the cationic emulsion with an ethanol-water solvent, stir evenly, add sepiolite powder, stir evenly, and let stand for 20 - 24 h, then add epoxy resin powder and stir evenly to obtain a hydrophobic emulsion.

[0030] The present invention experimented with a variety of polymerization monomers according to the above method to obtain a series of hydrophobic emulsions, and the specific monomer combinations are shown in Table 1.

[0031] Table 1 Different monomer combinations

[0032]

[0033]

[0034] The above-mentioned monomers are combined and pre-emulsified together with the cationic surfactant cetyltrimethylammonium chloride, and 2,2'-azobis(2-methylpropionamidine) dihydrochloride is used as an initiator to obtain 6 groups of cationic emulsions. Each group of cationic emulsions is respectively used to prepare a hydrophobic emulsion: the cationic emulsion is mixed with an ethanol-water solvent, stirred evenly, and left standing for 20 h, and then epoxy resin powder is added. After stirring evenly, a hydrophobic emulsion is obtained.

[0035] This batch of hydrophobic emulsions is respectively applied to aerogel fiber felts and aluminosilicate fiber felts. The fiber felts are immersed in the hydrophobic emulsion to make full contact with it. The immersion time is 24 hours. The modified fiber felts are transferred to an oven, and the drying temperature is 65 °C to obtain modified fiber felt hydrophobic materials. The hydrophobic effect of the modified fiber felts is tested: the material is weighed as W1, placed in a constant temperature and humidity chamber, and the conditions set for the constant temperature and humidity chamber are: temperature 50 °C, humidity 95%, and time 96 hours. After taking it out and weighing it as W2. The comparative example is an unmodified fiber felt material.

[0036] Mass moisture absorption rate = (W2 - W1) / W1.

[0037] Table 2 Test results of aerogel fiber felts

[0038]

[0039] Table 3 Test results of aluminosilicate fiber felts

[0040]

[0041] As can be seen from Table 2 and Table 3, the emulsion prepared from the monomers in Group 3 has the lowest moisture absorption rate, and after adding sepiolite powder, the water absorption rate is significantly improved.

[0042] Example 2

[0043] A preparation method of a modified epoxy resin hydrophobic emulsion for a thermal insulation material, comprising the following steps:

[0044] A. Under a nitrogen atmosphere, styrene, allyl caproate, dimethyldodecylallylammonium chloride, cetyltrimethylammonium chloride and deionized water are added into a container for pre-emulsification reaction;

[0045] Then the initiator is slowly added dropwise, and the reaction is continued to obtain emulsion A;

[0046] B. Under a nitrogen atmosphere, butyl acrylate, butyl methacrylate + dodecyl acrylate, cetyl trimethyl ammonium chloride and deionized water were added into a container for pre-emulsification reaction to obtain emulsion B;

[0047] C. Emulsion B and azobisisobutyramidine hydrochloride were slowly added dropwise into emulsion A together, and a cationic emulsion was obtained through reaction.

[0048] D. The cationic emulsion was mixed with an ethanol-water solvent at a ratio of 1:4. After stirring evenly, sepiolite powder was added, and after stirring evenly, it was left standing for 20 h. Then, epoxy resin powder was added, and after stirring evenly, a hydrophobic emulsion was obtained.

[0049] Example 3

[0050] A method for preparing a modified epoxy resin hydrophobic emulsion for thermal insulation materials, comprising the following steps:

[0051] A. Under a nitrogen atmosphere, styrene, allyl hexanoate, dimethyldodecylallylammonium chloride, cetyl trimethyl ammonium chloride and deionized water were added into a container for pre-emulsification reaction;

[0052] Then, an initiator was slowly added dropwise, and the reaction was continued to obtain emulsion A;

[0053] B. Under a nitrogen atmosphere, butyl acrylate, butyl methacrylate, dodecyl acrylate, cetyl trimethyl ammonium chloride and deionized water were added into a container for pre-emulsification reaction to obtain emulsion B;

[0054] C. Emulsion B and azobisisobutyramidine hydrochloride were slowly added dropwise into emulsion A together, and a cationic emulsion was obtained through reaction.

[0055] D. The cationic emulsion was mixed with an ethanol-water solvent at a ratio of 1:4. After stirring evenly, sepiolite powder was added, and after stirring evenly, it was left standing for 22 h. Then, epoxy resin powder was added, and after stirring evenly, a hydrophobic emulsion was obtained.

[0056] The mass ratio of the styrene, allyl hexanoate, and dimethyldodecylallylammonium chloride is 5:5:1; the mass ratio of the butyl acrylate, butyl methacrylate, and dodecyl acrylate is 5:4:2.

[0057] In steps A and B, the solid-liquid mass ratio of the reaction raw materials is 1:5, wherein cetyl trimethyl ammonium chloride accounts for 20% of the mass of the solid raw materials.

[0058] In step D, the mass ratio of the raw materials is: 25 parts of cationic emulsion, 50 parts of epoxy resin, 8 parts of sepiolite, 80 parts of ethanol, and 320 parts of deionized water.

[0059] Reaction conditions for pre-emulsification: temperature is room temperature, rotation speed is 800 rpm / min, pre-emulsification for 30 min; slowly add initiator to the emulsion at 85 °C, and keep the temperature for reaction for 2.5 h.

[0060] Example 4

[0061] A preparation method of a modified epoxy resin hydrophobic emulsion for thermal insulation materials, comprising the following steps:

[0062] A. Under a nitrogen atmosphere, add styrene, allyl hexanoate, dimethyldodecylallylammonium chloride, cetyltrimethylammonium chloride and deionized water into a container, and carry out a pre-emulsification reaction;

[0063] Then slowly add the initiator and continue the reaction to obtain emulsion A;

[0064] B. Under a nitrogen atmosphere, add butyl acrylate, butyl methacrylate, dodecyl acrylate, cetyltrimethylammonium chloride and deionized water into a container, and carry out a pre-emulsification reaction to obtain emulsion B;

[0065] C. Slowly add emulsion B and azodiisobutyramidine hydrochloride to emulsion A together, and react to obtain a cationic emulsion.

[0066] D. Mix the cationic emulsion with an ethanol-water solvent in a ratio of 1:4, stir evenly, add sepiolite powder, stir evenly, and let stand for 24 h, then add epoxy resin powder, stir evenly to obtain a hydrophobic emulsion.

[0067] The mass ratio of the styrene, allyl hexanoate, and dimethyldodecylallylammonium chloride is 5:5:1; the mass ratio of the butyl acrylate, butyl methacrylate, and dodecyl acrylate is 5:4:2.

[0068] In the steps A and B, the solid-liquid mass ratio of the reaction raw materials is 1:5, and among them, cetyltrimethylammonium chloride accounts for 20% of the mass of the solid raw materials.

[0069] In the step D, the mass ratio of the raw materials is: 35 parts of cationic emulsion, 50 parts of epoxy resin, 10 parts of sepiolite, 120 parts of ethanol and 480 parts of deionized water.

[0070] Reaction conditions for pre-emulsification: temperature is room temperature, rotation speed is 600 rpm / min, pre-emulsification for 30 min; slowly add initiator to the emulsion at 80 °C, and keep the temperature for reaction for 2 h.

[0071] The particle size of the sepiolite powder is 200 mesh.

[0072] Example 5

[0073] A preparation method of a modified epoxy resin hydrophobic emulsion for a heat-insulating material, comprising the following steps:

[0074] A. Under a nitrogen atmosphere, styrene, allyl hexanoate, dimethyldodecylallylammonium chloride, cetyltrimethylammonium chloride and deionized water are added into a container for pre-emulsification reaction;

[0075] Then an initiator is slowly added dropwise, and the reaction continues to obtain emulsion A;

[0076] B. Under a nitrogen atmosphere, butyl acrylate, butyl methacrylate, dodecyl acrylate, cetyltrimethylammonium chloride and deionized water are added into a container for pre-emulsification reaction to obtain emulsion B;

[0077] C. Emulsion B and azodiisobutyramidine hydrochloride are slowly added dropwise into emulsion A together, and a cationic emulsion is obtained by reaction.

[0078] D. The cationic emulsion is mixed with an ethanol-water solvent in a ratio of 1:4. After stirring evenly, sepiolite powder is added, stirred evenly, and left standing for 24 h. Then epoxy resin powder is added, and after stirring evenly, a hydrophobic emulsion is obtained.

[0079] The mass ratio of the styrene, allyl hexanoate, and dimethyldodecylallylammonium chloride is 5:5:1; the mass ratio of the butyl acrylate, butyl methacrylate, and dodecyl acrylate is 5:4:2.

[0080] In steps A and B, the solid-liquid mass ratio of the reaction raw materials is 1:5, and among them, cetyltrimethylammonium chloride accounts for 20% of the mass of the solid raw materials.

[0081] In step D, the mass ratio of the raw materials is: 28 parts of cationic emulsion, 50 parts of epoxy resin, 9 parts of sepiolite, 100 parts of ethanol and 400 parts of deionized water.

[0082] The reaction conditions for pre-emulsification: the temperature is room temperature, the rotation speed is 1000 rpm / min, and pre-emulsification is carried out for 30 min; the initiator is slowly added dropwise to the emulsion at 90 °C, and the heat preservation reaction is carried out for 3 h.

[0083] The particle size of the sepiolite powder is 200 mesh.

[0084] The above embodiments only represent the specific implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A method for preparing a modified epoxy resin hydrophobic emulsion for thermal insulation material, characterized in that , including the following steps: A. In a nitrogen atmosphere, a polymerization monomer, a cationic surfactant and deionized water are added into a container to perform a pre-emulsification reaction; then an initiator is slowly added dropwise and the reaction is continued to obtain an emulsion A; B. Under a nitrogen atmosphere, adding polymerization monomers, cationic surfactants and deionized water into a container to perform a pre-emulsification reaction to obtain an emulsion B; C. Slowly add emulsion B and initiator into emulsion A to react to obtain cationic emulsion. D. Mix the cationic emulsion with the ethanol-water solvent, stir evenly, and then add the sepiolite powder. Stir evenly and let stand for 20-24 hours, then add epoxy resin powder and stir evenly to obtain a hydrophobic emulsion.

2. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 1, characterized in that In the steps A and B, the solid-liquid mass ratio of the reaction raw materials is 1:5, wherein the cationic surfactant accounts for 20% of the mass of the solid raw materials.

3. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 1, characterized in that The polymerization monomers of step A are styrene, allyl hexanoate and dimethyl dodecyl allyl ammonium chloride, with a mass ratio of 5:5:1; the polymerization monomers of step B are butyl acrylate, butyl methacrylate and dodecyl acrylate, with a mass ratio of 5:4:

2.

4. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 1, characterized in that: In the step D, the mass ratio of the raw materials is: 25-35 parts of cationic emulsion, 50 parts of epoxy resin, 8-10 parts of sepiolite, 80-120 parts of ethanol and 300-500 parts of deionized water.

5. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 4, characterized in that: The volume ratio of the ethanol to the deionized water is 1:

4.

6. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 1, characterized in that: The cationic surfactant is a C12-C22 alkyl quaternary ammonium salt type cationic surfactant.

7. The method for preparing the modified epoxy resin hydrophobic emulsion for thermal insulation material according to claim 6, characterized in that: The cationic surfactant is hexadecyltrimethylammonium chloride.

8. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 1, characterized in that: The initiator is azobisisobutylamidine hydrochloride.

9. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 1, characterized in that: The reaction conditions of pre-emulsification are: room temperature, rotation speed 600-1000 rpm / min, and pre-emulsification for 30 min; Slowly add the initiator to the emulsion at 80-90°C and keep the reaction warm for 2-3 hours.

10. The method for preparing the modified epoxy resin hydrophobic emulsion of the thermal insulation material according to claim 1, characterized in that: The particle size of the sepiolite powder is 200 meshes.

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