Epoxy resin mortar and preparation method thereof

Abstract

The invention belongs to the technical field of building materials, and particularly relates to epoxy resin mortar and a preparation method thereof. The epoxy resin mortar comprises a component A, a component B and a component C according to the mass ratio of 1: (0.2-0.8): (3-8), the component A comprises epoxy resin, phenyl glycidyl ether, a defoaming agent and a coupling agent, the component B comprises an amino-terminated epoxy resin prepolymer and an accelerant, and the component C comprises graded sand and spherical expansible graphite. The initial expansion temperature of the spherical expandable graphite is less than or equal to 80 DEG C, and the particle size range is 10-50 microns. The epoxy resin mortar has the advantages of being low in shrinkage rate, large in single-time construction thickness, high in strength and high in adhesion, and is particularly suitable for the fields of repair and reinforcement, pouring and filling, pavement protection and the like with high requirements on the shrinkage rate.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to an epoxy resin mortar and a preparation method thereof. Background Art

[0002] Epoxy resin mortar is a high-strength, erosion-resistant, wear-resistant, and highly adhesive consolidation sealing material. It is widely used in the repair of damaged flow surfaces of hydraulic structures, the reinforcement of concrete structures, and the sealing and repair of surface defects such as honeycombs, rough surfaces, and exposed reinforcement.

[0003] The shrinkage of epoxy resin during the curing process is between 2% and 5%, and the finished product is very prone to deformation, warping, and even cracking. There are two main reasons for the shrinkage: 1. The van der Waals force between molecules in the liquid is transformed into the covalent bond in the cross-linked body, and the bond length of the covalent bond is shorter; 2. The reaction process releases a lot of heat, and it shrinks naturally after the heat is lost.

[0004] In order to reduce the shrinkage of epoxy resin, patent CN105440584A discloses a low shrinkage epoxy resin system and its preparation method, which introduces nano barium titanate into the system and uses coupling agents, ultrasonic treatment and other methods to achieve a 50% reduction in epoxy resin shrinkage. The preparation process of this method is complicated, high temperature curing is required, and the nano materials used are expensive. Patent CN103554842A discloses an epoxy grouting material, which synthesizes low-viscosity epoxy resin, cooperates with modified curing agent, active rubber toughening agent, and bicyclic lactone expansion monomer to reduce epoxy resin shrinkage, but the epoxy resin synthesis process of this scheme is complicated, the toughening agent is expensive, and the bicyclic lactone expansion monomer is not only expensive, but also the ring-opening reaction with the curing agent molecule is not sufficient, which limits its role.

[0005] Increasing the single construction thickness and reducing the curing shrinkage rate have always been important directions for the development of high-strength epoxy resin mortar. Summary of the invention

[0006] The invention aims to provide an epoxy resin mortar with large single construction thickness, low shrinkage and low cost and a preparation method thereof.

[0007] Specifically, the present invention provides the following technical solutions:

[0008] An epoxy resin mortar comprises a component A, a component B and a component C in a mass ratio of 1:(0.2-0.8):(3-8), wherein the component A comprises an epoxy resin, phenyl glycidyl ether (active diluent), a defoamer and a coupling agent, the component B comprises an amino-terminated epoxy resin prepolymer (curing agent) and an accelerator, and the component C comprises graded sand and spherical expandable graphite;

[0009] The initial expansion temperature of the spherical expandable graphite is ≤80°C, and the particle size ranges from 10 to 50 microns.

[0010] Preferably, the component A comprises, by weight, 70-95 parts of epoxy resin, 3-28 parts of phenyl glycidyl ether, 1-3 parts of defoaming agent, and 1-5 parts of coupling agent;

[0011] The B component includes 85-100 parts of amino-terminated epoxy resin prepolymer and 1-10 parts of accelerator;

[0012] The C component includes 95-99.5 parts of graded sand and 0.5-5 parts of spherical expandable graphite;

[0013] Further preferably, the B component also includes 0-10 parts by weight of a latent curing agent; more preferably, the latent curing agent is bis-N,N'-(methyl-butylmethylene)-diethylenetriamine, which is a ketimine that can react with water in a humid environment to generate a polyamine, and participate in the curing process of the epoxy resin, thereby improving the efficiency of epoxy curing in a humid environment and increasing the bonding strength of the wet base surface.

[0014] Preferably, the epoxy resin is bisphenol A epoxy resin and / or bisphenol F epoxy resin; more preferably, the epoxy resin is a mixture of 50-70wt% bisphenol A epoxy resin and 30-50wt% bisphenol F epoxy resin. The use of the above epoxy resin mixture can effectively avoid the crystallization problem of the epoxy resin when it is used at a lower temperature.

[0015] Preferably, the defoaming agent is a polysiloxane defoaming agent.

[0016] Preferably, the coupling agent is an epoxy-terminated silane coupling agent; more preferably, it is γ-glycidyloxypropyltrimethoxysilane.

[0017] Preferably, the amino-terminated epoxy resin prepolymer is an amino-terminated prepolymer formed by the reaction of epoxy resin and excess small molecule primary amine; further preferably, the small molecule primary amine is one or more of ethylenediamine, diethylenetriamine, 1,3-cyclohexanedimethylamine, isophoronediamine, and polyetheramine D230.

[0018] Preferably, the accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, o-hydroxybenzyldimethylamine, and N,N-dimethylaniline.

[0019] The present invention also provides a method for preparing the above-mentioned epoxy resin mortar, comprising the following steps:

[0020] S1. Evenly mix epoxy resin, phenyl glycidyl ether, defoamer and coupling agent to obtain component A;

[0021] S2, adding an accelerator and bis-N,N'-(methyl-butylmethylene)-diethylenetriamine to the amino-terminated epoxy resin prepolymer and mixing them evenly to obtain component B;

[0022] S3, mixing graded sand and spherical expandable graphite uniformly to obtain component C;

[0023] S4. Mix component A and component B evenly, then add component C, and mix evenly to obtain epoxy resin mortar.

[0024] Beneficial effects achieved by the present invention:

[0025] 1) The epoxy resin mortar provided by the present invention adds low-temperature spherical expandable graphite to the C component, which can improve the thermal conductivity of the mortar without affecting the fluidity of the mortar, facilitate the dissipation of reaction heat during the curing process, and the mortar single layer can be constructed with a higher thickness;

[0026] 2) The epoxy resin mortar provided by the present invention can effectively compensate for shrinkage during the plastic stage of epoxy resin (internal temperature exceeds the initial expansion temperature of expandable graphite) through the micro-expansion effect of spherical expandable graphite during a single, high-thickness construction process (internal temperature exceeds the initial expansion temperature of expandable graphite), and the comprehensive shrinkage rate is ≤2%; the present invention limits the particle size range of spherical expandable graphite to 10-50 microns, and studies have found that spherical expandable graphite with too small a particle size is prone to deteriorating the fluidity of the mortar, and at the same time, the expansion ratio is limited, which is not conducive to compensating for shrinkage;

[0027] 3) The epoxy resin mortar provided by the present invention uses phenyl glycidyl ether containing a rigid benzene ring as an active diluent and an amino-terminated epoxy resin prepolymer as a curing agent, which further reduces the reaction heat during the cross-linking process of the system, reduces the intrinsic shrinkage of the matrix, and increases the single construction;

[0028] 4) In the epoxy resin mortar provided by the present invention, the epoxy resin is preferably a mixture of 50-70wt% bisphenol A epoxy resin and 30-50wt% bisphenol F epoxy resin, which can effectively avoid the crystallization problem of the epoxy resin when used at a lower temperature. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is described clearly and completely below. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in the field or the product instructions are used.

[0030] In the following examples, the mechanical properties and 48h curing shrinkage of epoxy resin mortar are carried out in accordance with the relevant provisions of DL / T 5193 "Technical Specification for Epoxy Resin Mortar" and JTG 3420-2020 "Test Specification for Cement and Cement Concrete for Highway Engineering"; the curing reaction heat test evaluation method is: forming a 100×100×100mm sample, monitoring the maximum temperature T in the center of the sample during the curing process max The specimen molding and curing temperature is 23±2℃, and the relative humidity is 50±5%.

[0031] Bisphenol A epoxy resin uses Nan Ya NPEL-127E, bisphenol F epoxy resin uses NPEF-170; silane coupling agent uses KH-560; defoamer uses polysiloxane defoamer BYK-A530;

[0032] The accelerator is 2,4,6-tris(dimethylaminomethyl)phenol;

[0033] The preparation method of the amino-terminated epoxy resin prepolymer is specifically as follows: the preparation method of the amino-terminated epoxy resin prepolymer in the embodiment is as follows: dissolve small molecule primary amines (ethylenediamine, 1,3-cyclohexanedimethylamine, isophoronediamine, and polyetheramine) in toluene at a concentration of 1 mol / L; at 25°C, under mechanical stirring at 200±20r / min, slowly add epoxy resin, and the molar ratio of epoxy resin to small molecule primary amine is 1:1.5, 1:1.8, 1:2, and 1:2, respectively; after reacting for 2 hours, cool to room temperature, and remove the solvent by reduced pressure distillation to obtain the amino-terminated epoxy resin prepolymer.

[0034] The graded aggregate is a mixture of quartz sand of different particle sizes, with the proportion of each component being 10% for 10-50 mesh, 35% for 40-80 mesh, 40% for 200 mesh, and 15% for fly ash.

[0035] The spherical expandable graphite is expandable graphite with an initial expansion temperature of 76° C. and is obtained by crushing, screening and grading, and the particle size range is 10-50 microns.

[0036] The preparation methods of each embodiment are as follows:

[0037] Put epoxy resin, diluent, defoamer and silane coupling agent into the mixing tank in proportion, mix them evenly, and obtain component A;

[0038] Adding accelerator and bis-N,N'-(methyl-butylmethylene)-diethylenetriamine to the amino-terminated epoxy resin prepolymer in sequence and stirring evenly to obtain component B;

[0039] Add graded aggregate and spherical expandable graphite into a mixing container and mix them evenly to obtain component C;

[0040] Mix components A and B evenly, then add component C and mix evenly to obtain the product.

[0041] After casting the samples, the 28-day compressive strength, curing shrinkage and T max .

[0042] The formula ratio and performance data of each embodiment and comparative example are shown in Table 1. Among them, compared with Example 1, Comparative Example 1 does not add spherical expandable graphite; the B component of Comparative Example 2 adopts the more commonly used phenolic amine curing agent T31 on the current market. The results show that the epoxy resin mortar of the present invention has the advantages of low shrinkage (<2%), low reaction heat release, high strength (over 115MPa), and high adhesion. The inventor believes that there are two main reasons for its low shrinkage rate: one is that the low-temperature spherical expandable graphite effectively compensates for the early plastic shrinkage when the internal temperature of the mortar exceeds the initial expansion temperature; the second is that the use of phenyl glycidyl ether containing rigid benzene rings as an active diluent and amino-terminated epoxy resin prepolymer as a curing agent further reduces the reaction heat during the cross-linking process of the system and reduces the intrinsic shrinkage of the matrix. The two factors work synergistically to reduce the shrinkage rate of the mortar. At the same size, the maximum temperature inside the epoxy resin mortar is significantly lower than that of the existing technology. This is mainly because the use of terminal amine prepolymer reduces the heat of polymerization reaction, and the addition of spherical expandable graphite improves the thermal conductivity of the matrix, which is conducive to the rapid dissipation of heat, and the mortar can be constructed with a larger thickness in a single time.

[0043] Table 1

[0044]

[0045]

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An epoxy resin mortar, characterized in that: The invention comprises a component A, a component B and a component C in a mass ratio of 1:(0.2-0.8):(3-8), wherein the component A comprises an epoxy resin, phenyl glycidyl ether, a defoamer and a coupling agent, the component B comprises an amino-terminated epoxy resin prepolymer and a accelerator, and the component C comprises graded sand and spherical expandable graphite; The initial expansion temperature of the spherical expandable graphite is ≤80°C, and the particle size ranges from 10 to 50 microns.

2. The epoxy resin mortar according to claim 1, characterized in that: In parts by weight, the component A includes 70-95 parts of epoxy resin, 3-28 parts of phenyl glycidyl ether, 1-3 parts of defoaming agent, and 1-5 parts of coupling agent; The B component includes 85-100 parts of amino-terminated epoxy resin prepolymer and 1-10 parts of accelerator; The C component includes 95-99.5 parts of graded sand and 0.5-5 parts of spherical expandable graphite.

3. The epoxy resin mortar according to claim 2, characterized in that: The B component also includes 0-10 parts by weight of a latent curing agent; Preferably, the latent curing agent is bis-N,N'-(methyl-butylmethylene)-diethylenetriamine.

4. The epoxy resin mortar according to any one of claims 1 to 3, characterized in that: The epoxy resin is bisphenol A epoxy resin and / or bisphenol F epoxy resin; Preferably, the epoxy resin is a mixture of 50-70 wt % of bisphenol A epoxy resin and 30-50 wt % of bisphenol F epoxy resin.

5. The epoxy resin mortar according to any one of claims 1 to 3, characterized in that: The defoaming agent is a polysiloxane defoaming agent.

6. The epoxy resin mortar according to any one of claims 1 to 3, characterized in that: The coupling agent is an epoxy-terminated silane coupling agent, preferably γ-glycidyloxypropyltrimethoxysilane.

7. The epoxy resin mortar according to any one of claims 1 to 3, characterized in that: The amino-terminated epoxy resin prepolymer is an amino-terminated prepolymer formed by the reaction of epoxy resin and excess small molecular primary amine; Preferably, the small molecule primary amine is one or more of ethylenediamine, diethylenetriamine, 1,3-cyclohexanedimethylamine, isophoronediamine, and polyetheramine D230.

8. The epoxy resin mortar according to any one of claims 1 to 3, characterized in that: The accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, o-hydroxybenzyldimethylamine and N,N-dimethylaniline.

9. The method for preparing the epoxy resin mortar according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Evenly mix epoxy resin, phenyl glycidyl ether, defoamer and coupling agent to obtain component A; S2, adding an accelerator and bis-N,N'-(methyl-butylmethylene)-diethylenetriamine to the amino-terminated epoxy resin prepolymer and mixing them evenly to obtain component B; S3, mixing graded sand and spherical expandable graphite uniformly to obtain component C; S4. Mix component A and component B evenly, then add component C, and mix evenly to obtain epoxy resin mortar.

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