Bi-component modified epoxy anchor adhesive and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, and discloses a bi-component modified epoxy anchor adhesive, which comprises an A component epoxy resin main material and a B component auxiliary agent, and is characterized in that the A component is a modified cellulose / polyurea modified epoxy resin compound. The double-component modified epoxy embedded steel bar glue has excellent bonding performance and can be rapidly hardened. The preparation method of the bi-component modified epoxy anchor adhesive comprises the following steps: step 1, preparing isocyanate modified cellulose nanocrystals; step 2, preparation of a component A: mixing epoxy resin, a polyurea prepolymer, isocyanate modified cellulose nanocrystals, a flexibilizer, a filler and a diluent in proportion to obtain the component A; step 3, preparation of a component B: mixing a curing agent, a flexibilizer and a bonding accelerator in proportion to obtain the component B; and step 4, uniformly mixing the component A and the component B to obtain the bi-component modified epoxy anchor adhesive. And the bonding strength can be improved while rapid curing and curing are realized.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, and in particular to a two-component modified epoxy rebar-embedding adhesive and a preparation method thereof. Background Art

[0002] Epoxy rebar glue is a two-component epoxy adhesive of A and B. It is a high-performance adhesive used for building structure reinforcement. It is mainly made of epoxy resin and auxiliary additives such as curing agent, diluent, toughening agent, etc. It generally has the advantages of thixotropy, high tensile and shear strength, excellent aging resistance, fatigue resistance, and load-displacement characteristics. Epoxy rebar glue is mainly used in building reinforcement projects. Through bonding and locking, it firmly combines concrete and steel components together to achieve the effect of pre-embedded.

[0003] Curing time is crucial to the bonding strength of epoxy rebar glue. If the curing time is insufficient, the glue may not be fully cured, resulting in insufficient bonding strength, which will directly affect the effect of rebar reinforcement and may even cause safety hazards when the reinforced structure is under stress. During the curing period, the epoxy rebar glue needs to be fully cured through chemical reactions, which is the basis for its bonding effect. This process requires sufficient time to ensure that the glue can be fully cured and reach the expected bonding strength.

[0004] Chinese patent document CN106118567A discloses a two-component injection epoxy rebar glue and a preparation method thereof. The two-component injection epoxy rebar glue is formed by mixing component A and component B in a mass ratio of 5:1, wherein component A consists of bisphenol A epoxy resin, bisphenol F epoxy resin, diluent, toughening agent, thixotropic agent, coupling agent, and filler; component B consists of modified amine curing agent, thixotropic agent, coupling agent, and filler. The injection epoxy rebar glue is a fast-curing rebar glue after a special formula design. The structural adhesive has high colloid strength after normal curing for seven days, with a splitting tensile strength of 10MPa and a flexural strength of 65MPa; the adhesive has strong bonding ability, and the bonding strength with concrete under constraint conditions reaches 18MPa.

[0005] Chinese patent document CN103614104B discloses a low-temperature epoxy anchor glue and a preparation method thereof, comprising two components, A and B. When in use, the weight mixing ratio of component A to component B is 2:0.9-1.1; component A comprises the following components: bisphenol A epoxy resin, low-viscosity bisphenol F epoxy resin, active diluent, toughening agent 1, toughening agent 2, filler, rheological additive and thixotropic agent; component B comprises the following components: phenolic amine curing agent, aromatic amine curing agent, accelerator, coupling agent, anti-precipitation agent and filler.

[0006] Chinese patent document CN106118567A has the following disadvantages: after using epoxy anchor glue, a long curing time is required to improve the bonding strength after curing, and the final bonding strength after curing is still insufficient. Summary of the invention

[0007] In order to solve the technical problem of how to quickly cure and solidify while improving the bonding strength, the present invention provides a two-component modified epoxy rebar embedding adhesive, comprising a component A epoxy resin main material and a component B auxiliary additive, characterized in that: the component A is a modified cellulose / polyurea modified epoxy resin composite.

[0008] Preferably, the modified cellulose / polyurea-modified epoxy resin composite is prepared from modified cellulose, polyurea prepolymer and epoxy resin.

[0009] In order to further improve the bonding strength after curing, the modified cellulose adopts isocyanate-modified cellulose.

[0010] Furthermore, the isocyanate-modified cellulose adopts isocyanate-modified cellulose nanocrystals.

[0011] Preferably, component A also includes a toughening agent, a filler and a diluent.

[0012] Furthermore, the mass ratio of epoxy resin: polyurea prepolymer: modified cellulose: toughening agent: filler: diluent in component A is 50-100:10-20:1-3:5-10:15-20:20-30.

[0013] Preferably, the curing agent, toughening agent and adhesion promoter are used in component B, and the mass ratio of the curing agent, toughening agent and adhesion promoter is 20-30:3-8:1-3.

[0014] A method for preparing a two-component modified epoxy reinforcing bar adhesive comprises the following steps: Step 1, preparing isocyanate-modified cellulose nanocrystals; Step 2, preparation of component A: epoxy resin, polyurea prepolymer, isocyanate-modified cellulose nanocrystals, toughening agent, filler, and diluent are mixed in proportion to obtain component A; Step 3, preparation of component B: the curing agent, toughening agent and adhesion promoter are mixed in proportion to obtain component B; Step 4: Component A and component B are mixed evenly to obtain a two-component modified epoxy rebar adhesive.

[0015] Preferably, the isocyanate-modified cellulose nanocrystals are prepared by dissolving the dried cellulose nanocrystal powder in a non-protonic polar solvent, adding isocyanate and mixing evenly, successfully attaching the isocyanate groups to the surface of the cellulose nanocrystals, and centrifuging and drying to obtain isocyanate-modified cellulose nanocrystals.

[0016] The present invention has the following beneficial effects: 1. The functionalized cellulose nanocrystals in the present invention can react with the curing agent to achieve uniform dispersion in the matrix. The isocyanate-modified cellulose nanocrystals can also promote the polymerization reaction of the epoxy resin and the curing agent with the polyurea prepolymer in the absence of a catalyst, thereby increasing the reaction rate. At the same time, the polyurea prepolymer and the modified cellulose nanocrystals work together to form a cross-linked network structure in the epoxy resin system, thereby ensuring that the epoxy rebar-anchoring adhesive still maintains good mechanical properties under a low-viscosity state. The present invention not only improves the bonding strength of the epoxy rebar-anchoring adhesive but also shortens the curing time, thereby forming a two-component modified epoxy rebar-anchoring adhesive with excellent bonding properties and rapid setting. The isocyanate-modified cellulose nanocrystals also give the material excellent durability and UV resistance.

[0017] 2. The raw materials in the present invention are easy to obtain, the process steps are simple, and the present invention has a wide range of application potentials and can be used in civil engineering, construction, transportation and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a comparison chart of the curing time-bonding strength curves of the two-component modified epoxy anchor glue of the present invention and comparative examples 1 and 2. DETAILED DESCRIPTION

[0019] The following is further described in detail through specific implementation methods: In the present invention, the raw materials are as follows: 1. Epoxy resin: at least one of epoxy resin E51, epoxy resin E44, and epoxy resin 609; 2. Curing agent: at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine and triethylenetetramine; 3. Cellulose nanocrystals: diameter 10-20nm, length 100-400nm; 4. Isocyanate: at least one of hexamethylene diisocyanate, isophorone diisocyanate and toluene-2,4-diisocyanate; 5. Amino-terminated polyether: at least one of amino-terminated polyether D-230, amino-terminated polyether ZD-123 and amino-terminated polyether ZD-1500; 6. Aprotic polar solvent: at least one of dimethyl sulfoxide, N,N-dimethylformamide, and acetonitrile; 7. Adhesion promoter: at least one of oligomer siloxane, aminosiloxane, and vinyl oligomer siloxane; 8. Filler: at least one of talc, nano calcium carbonate and kaolin; 9. Toughening agent: at least one of triethyl phosphate, tricresyl phosphate, and dibutyl phthalate; 10. Diluent: at least one of diethylene glycol diether, ethyl propionate and ethyl acetate.

[0020] The raw materials of the present invention can all be directly purchased on the market.

[0021] A two-component modified epoxy anchor glue is composed of two groups of raw materials, A and B, wherein the mass ratio of the two components A and B is preferably 100:20-40. The A component is a modified cellulose nanocrystal / polyurea modified epoxy resin composite, a toughening agent, a filler and a diluent; the B component is a curing agent, a toughening agent and a bonding accelerator.

[0022] Example 1 A preparation method of a two-component modified epoxy reinforcing bar adhesive. (1) Preparation of isocyanate-modified cellulose nanocrystals: 20 g of cellulose nanocrystal powder was pre-dried in an oven at 120 °C for 1 hour, dissolved in 100 g of dimethyl sulfoxide solvent by ultrasonication, and 20 g of hexamethylene diisocyanate was dripped into the reaction solution dropwise. After continuous stirring at room temperature for 2 hours, the isocyanate groups were successfully connected to the surface of the cellulose nanocrystals. The cellulose nanocrystals were centrifuged and dried to obtain isocyanate-modified cellulose nanocrystal particles (CNC-NCO). (2) Preparation of polyurea prepolymer: Weigh 45 g of amino-terminated polyether D-230 and remove water at high temperature at 120°C for 2 h, then cool to room temperature; weigh 100 g of hexamethylene diisocyanate and heat to 80°C, add amino-terminated polyether D-230 dropwise and continue stirring to obtain an isocyanate-terminated amino-terminated prepolymer, namely, a polyurea prepolymer; (3) Preparation of component A: Weigh 50 parts of epoxy resin E51, 15 parts of polyurea prepolymer, 2 parts of isocyanate-modified cellulose nanocrystals, 5 parts of triethyl phosphate, 15 parts of talc, and 20 parts of diethylene glycol diether and stir at room temperature for 1 hour to obtain component A; (4) Preparation of component B: Weigh 22 g of ethylenediamine, 3 g of triethyl phosphate, and 2 g of oligomer siloxane, stir them evenly, and remove bubbles under vacuum to obtain component B; (5) Mix component A and component B evenly at room temperature to obtain a two-component modified epoxy rebar adhesive.

[0023] Example 2 A preparation method of a two-component modified epoxy reinforcing bar adhesive. (1) Preparation of isocyanate-modified cellulose nanocrystals: 20 g of cellulose nanocrystal powder was pre-dried in an oven at 120 °C for 1 hour, dissolved in 100 g of N,N-dimethylformamide solvent by ultrasonication, and 20 g of isophorone diisocyanate was dripped into the reaction solution dropwise. After continuous stirring at room temperature for 2 hours, the isocyanate groups were successfully connected to the surface of the cellulose nanocrystals. The mixture was centrifuged and dried to obtain isocyanate-modified cellulose nanocrystal particles (CNC-NCO). (2) Preparation of polyurea prepolymer: Weigh 45g of amino-terminated polyether ZD-123 and remove water at high temperature of 120°C for 2h, then cool to room temperature; weigh 100g of isophorone diisocyanate and heat to 80°C, add amino-terminated polyether ZD-123 dropwise and continue stirring to obtain isocyanate-terminated amino-terminated prepolymer, i.e., polyurea prepolymer; (3) Preparation of component A: Weigh 90 g of epoxy resin E44, 20 g of polyurea prepolymer, 3 g of isocyanate-modified cellulose nanocrystals, 10 g of tricresyl phosphate, 16 g of nano-calcium carbonate, and 25 g of ethyl propionate and stir at room temperature for 1 h to obtain component A; (4) Preparation of component B: Weigh 30 g of hexamethylenediamine, 8 g of tricresyl phosphate, and 3 g of aminosiloxane, stir evenly, and remove bubbles under vacuum to obtain component B; (5) Mix component A and component B evenly at room temperature to obtain a two-component modified epoxy rebar adhesive.

[0024] Comparative Example 1 Preparation method of epoxy reinforcing bar adhesive containing only modified cellulose nanocrystals, (1) Preparation of isocyanate-modified cellulose nanocrystals: 20 g of cellulose nanocrystal powder was pre-dried in an oven at 120 °C for 1 hour, dissolved in 100 g of dimethyl sulfoxide solvent by ultrasonication, and 20 g of hexamethylene diisocyanate was dripped into the reaction solution dropwise. After continuous stirring at room temperature for 2 hours, the isocyanate groups were successfully connected to the surface of the cellulose nanocrystals. The cellulose nanocrystals were centrifuged and dried to obtain isocyanate-modified cellulose nanocrystal particles (CNC-NCO). (2) Preparation of component A: Weigh 50 parts of epoxy resin E51, 2 parts of isocyanate-modified cellulose nanocrystals, 5 parts of triethyl phosphate, 15 parts of talc, and 20 parts of diethylene glycol diether and stir at room temperature for 1 hour to obtain component A; (4) Preparation of component B: Weigh 22 g of ethylenediamine, 3 g of triethyl phosphate, and 2 g of oligomer siloxane, stir them evenly, and remove bubbles under vacuum to obtain component B; (5) Mix component A and component B evenly at room temperature to obtain a two-component epoxy rebar adhesive.

[0025] Comparative Example 2 Preparation method of epoxy reinforcing bar adhesive with only polyurea prepolymer added, (1) Preparation of polyurea prepolymer: Weigh 45 g of amino-terminated polyether D-230 and remove water at high temperature at 120°C for 2 h, then cool to room temperature; weigh 100 g of hexamethylene diisocyanate and heat to 80°C, add amino-terminated polyether D-230 dropwise and continue stirring to obtain an isocyanate-terminated amino-terminated prepolymer, i.e., a polyurea prepolymer; (2) Preparation of component A: Weigh 90 g of epoxy resin E51, 20 g of polyurea prepolymer, 10 g of triethyl phosphate, 16 g of talc, and 25 g of diethylene glycol diether and stir at room temperature for 1 h to obtain component A; (3) Preparation of component B: Weigh 30 g of ethylenediamine, 8 g of triethyl phosphate, and 3 g of oligomer siloxane, stir them evenly, and remove bubbles under vacuum to obtain component B; (4) Mix component A and component B evenly at room temperature to obtain a two-component epoxy rebar adhesive.

[0026] Comparative Example 3 A method for preparing epoxy reinforcing bar adhesive without adding polyurea prepolymer and modified cellulose nanocrystals, (1) Preparation of component A: Weigh 90 g of epoxy resin E51, 10 g of triethyl phosphate, 16 g of talc, and 25 g of diethylene glycol diether and stir at room temperature for 1 h to obtain component A; (2) Preparation of component B: Weigh 30 g of ethylenediamine, 8 g of triethyl phosphate, and 3 g of oligomer siloxane, stir them evenly, and remove bubbles under vacuum to obtain component B; (3) Mix component A and component B evenly at room temperature to obtain a two-component epoxy rebar adhesive.

[0027] Table 1 Test items Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Test Standards Viscosity of mixture (25℃, Pa.S) 20 20.5 21 20.5 20 GB / T 22314 Curing time (25℃, h) 12 12 18 20 24 - Bond strength with concrete (MPa) 25.6 26.1 17.2 20.6 14.8 Appendix E to GB 50550-2010 Splitting tensile strength (MPa) 22 21.5 18 20 16.5 Appendix E to GB 50728-2011 In the above table, Example 1 and Example 2 use isocyanate-modified cellulose nanocrystals and polyurea prepolymers to prepare two-component modified epoxy anchor glue, which only requires 12 hours of curing time to increase the bonding strength to more than 25 MPa, and the viscosity and splitting tensile strength of the mixture are maintained at normal levels; Comparative Example 1 is to prepare a two-component epoxy rebar adhesive by adding only isocyanate-modified cellulose nanocrystals. After 18 hours of curing time, the bonding strength is only 17.2 MPa.

[0028] Comparative Example 2 is to prepare a two-component epoxy rebar adhesive by adding only polyurea prepolymer. After 20 hours of curing time, the bonding strength is only 20.6 MPa.

[0029] Comparative Example 3 is a two-component epoxy rebar adhesive prepared without adding isocyanate-modified cellulose nanocrystals and polyurea prepolymer. After 24 hours of curing, the bonding strength is only 14.8 MPa.

[0030] Attached Figure 1 , which are respectively the bonding strength variation curves of Example 1, Example 2 and Comparative Examples 1-3 during the curing process. Example 1 and Example 2 achieve curing bonding significantly faster than Comparative Examples 1-3, and the bonding strength is also higher than Comparative Examples 1-3.

[0031] In Example 1 and Example 2, isocyanate-modified cellulose nanocrystals and polyurea prepolymers work together to form a cross-linked network structure in the epoxy resin system, ensuring that the epoxy rebar anchoring adhesive still maintains good mechanical properties under low viscosity conditions, thereby improving the bonding strength of the epoxy rebar anchoring adhesive and shortening the curing time, thereby forming a two-component modified epoxy rebar anchoring adhesive with excellent bonding properties and rapid setting.

[0032] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A two-component modified epoxy anchor glue, comprising component A epoxy resin main material and component B auxiliary additive, characterized in that: The component A is a modified cellulose / polyurea modified epoxy resin composite.

2. The two-component modified epoxy anchoring adhesive according to claim 1, characterized in that: The modified cellulose / polyurea modified epoxy resin composite is prepared from modified cellulose, polyurea prepolymer and epoxy resin.

3. The two-component modified epoxy anchoring adhesive according to claim 2, characterized in that: The modified cellulose is isocyanate-modified cellulose.

4. The two-component modified epoxy anchoring adhesive according to claim 3, characterized in that: The isocyanate-modified cellulose adopts isocyanate-modified cellulose nanocrystals.

5. The two-component modified epoxy reinforcing bar adhesive according to claim 4, characterized in that: Component A also includes toughening agents, fillers and diluents.

6. The two-component modified epoxy reinforcing bar adhesive according to claim 5, characterized in that: The mass ratio of epoxy resin: polyurea prepolymer: modified cellulose: toughening agent: filler: diluent in component A is 50-100:10-20:1-3:5-10:15-20:20-30.

7. The two-component modified epoxy reinforcing bar adhesive according to claim 6, characterized in that: Component B uses a curing agent, a toughening agent and a bonding promoter, and the mass ratio thereof is 20-30:3-8:1-3.

8. A method for preparing a two-component modified epoxy reinforcing bar adhesive, characterized in that: The following steps are involved: Step 1, preparing isocyanate-modified cellulose nanocrystals; Step 2, preparation of component A: epoxy resin, polyurea prepolymer, isocyanate-modified cellulose nanocrystals, toughening agent, filler, and diluent are mixed in proportion to obtain component A; Step 3, preparation of component B: the curing agent, toughening agent and adhesion promoter are mixed in proportion to obtain component B; Step 4: Component A and component B are mixed evenly to obtain a two-component modified epoxy rebar adhesive.

9. The method for preparing the two-component modified epoxy reinforcing bar adhesive according to claim 8, characterized in that: In step 1, preparation of isocyanate-modified cellulose nanocrystals: the cellulose nanocrystal powder is dried and dissolved in a non-protonic polar solvent, isocyanate is added and mixed evenly, the isocyanate groups are successfully connected to the surface of the cellulose nanocrystals, and centrifugal drying is performed to obtain isocyanate-modified cellulose nanocrystals.

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