A cold storage floor repair mortar and its preparation method

Abstract

This invention relates to the field of repair mortar preparation technology, specifically to a cold storage floor repair mortar and its preparation method. The preparation method includes the following steps: S1. Preparation of modified MMA resin; S2. Mixing 72-90 parts of mixed powder, 5-8 parts of barium sulfate, and 10-12 parts of rigid polyurethane foam powder to obtain powder aggregate; S3. Mixing 100-120 parts of modified MMA resin, 2-4 parts of initiator, and 300-400 parts of powder aggregate, stirring at 200-300 r / min for 2-3 min, and obtaining the cold storage floor repair mortar after uniform mixing. The modified MMA resin system of this invention has a low odor and can improve adhesion to the concrete substrate, avoiding the debonding problem of sulfur-aluminum cementitious materials. The addition of recycled rigid polyurethane foam powder reduces the thermal conductivity of the mortar, effectively preventing frost heave damage to the concrete substrate at low temperatures, while also conforming to the concept of green manufacturing.

Description

Technical Field

[0001] This invention relates to the field of repair mortar preparation technology, specifically to a cold storage floor repair mortar and its preparation method. Background Technology

[0002] With the improvement of people's living standards, the number of cold storage facilities under construction and already built in China has increased rapidly. Due to the frequent impact of forklifts on the floors, damage to the cold storage floors is common. Currently, the main materials for repairing cold storage floors include aluminum sulfate rapid-hardening cement, epoxy mortar, and polyurea repair materials. Aluminum sulfate rapid-hardening cement can be properly cured at -5 to 0℃ using warm water and with insulation by covering it with cotton blankets. However, the inorganic material has poor adhesion to the substrate and is prone to detachment. Epoxy mortar and polyurea repair materials can cure quickly at room temperature, but the polymer reaction slows down or even stops as the temperature decreases, which will seriously affect the normal use of the cold storage. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a cold storage floor repair mortar and its preparation method. This invention aims to develop a novel floor repair material with high reactivity, flexible reaction rate adjustment, and normal usability under both normal and low temperature conditions. Even at low temperatures, the mortar can cure within 2 hours, enabling rapid traffic access without affecting the normal use of the cold storage facility.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A method for preparing a cold storage floor repair mortar includes the following preparation steps:

[0006] S1. Preparation of modified MMA resin:

[0007] S11. By mass, add 80-100 parts of modified ester mixture to the reactor, heat the reactor to 70-90℃, add 0.5-1 parts of initiator and react for 3-4 hours, cool down to 48-52℃ and distill under reduced pressure, add 1-3 parts of 52# paraffin and 0.5-1 parts of polymerization inhibitor at this temperature.

[0008] S12. After cooling the mixture obtained in step S11 to room temperature, add 1-2 parts of amine accelerator and stir at 300-400 r / min for 15-20 min to obtain MMA prepolymer;

[0009] S13. Mix 60-80 parts of modified diluent with the MMA prepolymer obtained in step S12, and stir at a speed of 250-300 r / min for 15-20 min to obtain modified MMA resin;

[0010] S2. Mix 72-90 parts of mixed powder, 5-8 parts of barium sulfate, and 10-12 parts of rigid polyurethane foam powder to obtain powder aggregate;

[0011] S3. Mix 100-120 parts of modified MMA resin, 2-4 parts of initiator and 300-400 parts of powder aggregate, stir at 200-300 r / min for 2-3 min, and after mixing evenly, obtain cold storage floor repair mortar.

[0012] Preferably, the preparation of the modified ester mixture includes the following steps:

[0013] S111. By weight, add 60-75 parts of methyl methacrylate, 8-10 parts of acrylic acid, 5-7 parts of n-butyl methacrylate, 10-12 parts of methyl acrylate, and 4-6 parts of triethylene glycol di-2-methacrylate to a reaction vessel, stir at 200-300 r / min for 10-15 min, and heat to 70-90℃ to react for 25-30 min;

[0014] S112. Add 1-2 parts of initiator to 60-70 parts of methyl methacrylate, stir at 300-400 r / min for 20-25 min to obtain a monomer mixture;

[0015] S113. The monomer mixture is slowly added to the mixture obtained in step S111 at a dropping rate of 2 g / min. After reacting for 3-4 h, the temperature is lowered to 50 °C, and then vacuum distilled. After cooling to room temperature, the modified ester mixture is obtained.

[0016] Preferably, the preparation of the modified diluent includes the following steps:

[0017] S1121. By weight, add a total of 0.5-1 parts of initiator in 4-5 portions to a reactor containing 80-100 parts of methyl methacrylate and 3-5 parts of tetrahydrofuran, then raise the temperature to 50-70℃ and maintain the reaction for 2 hours.

[0018] S1122. The solution obtained in step S1121 is kept at 50°C and subjected to vacuum distillation to remove unreacted monomers and solvent volatiles, finally obtaining the modified diluent.

[0019] Preferably, the polymerization inhibitor is selected from hydroquinone monomethyl ether.

[0020] Preferably, the amine accelerator is selected from one or more of triethylenediamine, triethylamine, iron acetylacetone, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, N,N-diethylaniline, and N,N-dihydroxyethyl-p-toluidine.

[0021] Preferably, the initiator is selected from benzoyl peroxide.

[0022] Preferably, the mixed powder in step S2 is composed of quartz sand, quartz powder, and calcium powder, with a mass ratio of 40-50:20-25:12-15.

[0023] Preferably, the polyurethane rigid foam powder is obtained by recycling and crushing polyurethane foam insulation material from discarded refrigerators and insulation boards for reuse.

[0024] A cold storage floor repair mortar is prepared by the above-mentioned preparation method.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The modified diluent of this invention replaces the traditional monomer, significantly reducing the content of volatile monomers, effectively improving the irritating odor of the resin, and achieving low odor or no odor. In synergy with the modified ester mixture, the prepared cold storage floor repair mortar can still achieve rapid curing within 2 hours in a low temperature environment of -30~0℃. While ensuring the low temperature reactivity of the resin, it reduces the irritating odor during the construction process and achieves environmental friendliness.

[0027] 2. The modified MMA resin system of this invention has a low odor and can improve adhesion to concrete substrates, avoiding the debonding problem of sulfur-aluminum cementitious materials. The addition of recycled polyurethane rigid foam powder reduces the thermal conductivity of the mortar, effectively preventing frost heave damage to the concrete substrate at low temperatures, while also conforming to green manufacturing principles. Attached Figure Description

[0028] Figure 1 This is a process flow diagram of the preparation process of the cold storage floor repair mortar of the present invention;

[0029] Figure 2 This is a flow chart of the preparation process of the modified ester mixture of the present invention;

[0030] Figure 3 This is a flowchart illustrating the preparation process of the modified diluent of this invention. Detailed Implementation

[0031] The present invention will now be clearly and completely described in conjunction with embodiments thereof. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] Please see Figure 1-3 The present invention provides a technical solution:

[0033] This invention can be used normally under both room temperature and low temperature conditions. Even at low temperatures, the mortar can be cured within 2 hours. This invention also innovatively uses low molecular weight MMA resin as a modifier and diluent, replacing the monomers used in traditional materials, effectively reducing the irritating odor of the material and achieving environmental friendliness. Furthermore, this invention innovatively uses rigid polyurethane foam powder, realizing the reuse of solid waste. At the same time, the addition of rigid polyurethane foam powder results in a lower thermal conductivity of the repair mortar, effectively preventing damage to the concrete substrate from low temperatures.

[0034] Example 1

[0035] A method for preparing cold storage floor repair mortar:

[0036] Before preparing the cold storage floor repair mortar, the modified diluent and modified ester mixture should be prepared first:

[0037] The preparation of the modified diluent includes the following steps:

[0038] S1121. Add 0.5g of benzoyl peroxide in four portions to a reactor containing 80g of methyl methacrylate and 3g of tetrahydrofuran, then raise the temperature to 50°C and maintain the reaction for 2 hours.

[0039] S1122. The solution obtained in step S1121 is kept at 50°C and subjected to vacuum distillation to remove unreacted monomers and solvent volatiles, and finally the modified diluent is obtained;

[0040] The preparation of modified ester mixtures includes the following steps:

[0041] S111. Add 60g of methyl methacrylate, 8g of acrylic acid, 5g of n-butyl methacrylate, 10g of methyl acrylate, and 4g of triethylene glycol di-2-methacrylate to a reaction vessel, stir at 200r / min for 10min, and heat to 70℃ for 25min.

[0042] S112. Add 1g of benzoyl peroxide to 60g of methyl methacrylate and stir at 300r / min for 20min to obtain a monomer mixture;

[0043] S113. The monomer mixture is slowly added to the mixture obtained in step S111 at a dropping rate of 2 g / min. After reacting for 3 h, the temperature is lowered to 50 °C, and then vacuum distilled. After cooling to room temperature, the modified ester mixture is obtained.

[0044] S1. Preparation of modified MMA resin:

[0045] S11. Add 80g of modified ester mixture to the reactor, heat the reactor to 70℃, add 0.5g of benzoyl peroxide and react for 3h, cool to 48℃ and then distill under reduced pressure. At this temperature, add 1g of 52# paraffin and 0.5g of hydroquinone monomethyl ether.

[0046] S12. After cooling the mixture obtained in step S11 to room temperature, add 1g of triethylenediamine and stir at 300r / min for 15min to obtain MMA prepolymer;

[0047] S13. Mix 60g of modified diluent with the MMA prepolymer obtained in step S12 and stir at 250r / min for 15min to obtain modified MMA resin;

[0048] S2. Mix 72g of mixed powder (composed of quartz sand, quartz powder, and calcium powder, with masses of 40g, 20g, and 12g respectively), 5g of barium sulfate, and 10g of polyurethane rigid foam powder (obtained by recycling and crushing polyurethane foam insulation material from scrapped refrigerators and insulation boards) to obtain powder aggregate.

[0049] S3. Mix 100g of modified MMA resin, 2g of benzoyl peroxide and 300g of powder aggregate, stir at 200r / min for 2min, and after mixing evenly, obtain cold storage floor repair mortar.

[0050] Example 2

[0051] A method for preparing cold storage floor repair mortar:

[0052] Before preparing the cold storage floor repair mortar, the modified diluent and modified ester mixture should be prepared first:

[0053] The preparation of the modified diluent includes the following steps:

[0054] S1121. Add 1g of benzoyl peroxide in 5 portions to a reactor containing 100g of methyl methacrylate and 5g of tetrahydrofuran, then raise the temperature to 70℃ and maintain the reaction for 2h.

[0055] S1122. The solution obtained in step S1121 is kept at 50°C and subjected to vacuum distillation to remove unreacted monomers and volatiles, and finally the modified diluent is obtained;

[0056] The preparation of modified ester mixtures includes the following steps:

[0057] S111. Add 75g of methyl methacrylate, 10g of acrylic acid, 7g of n-butyl methacrylate, 12g of methyl acrylate, and 6g of triethylene glycol di-2-methacrylate to a reaction vessel, stir at 300r / min for 15min, and heat to 90℃ for 30min.

[0058] S112. Add 2g of benzoyl peroxide to 70g of methyl methacrylate and stir at 400r / min for 25min to obtain a monomer mixture;

[0059] S113. The monomer mixture is slowly added to the mixture obtained in step S111 at a dropping rate of 2 g / min. After reacting for 4 h, the temperature is lowered to 50 °C, and then vacuum distilled. After cooling to room temperature, the modified ester mixture is obtained.

[0060] S1. Preparation of modified MMA resin:

[0061] S11. Add 100g of modified ester mixture to the reactor, heat the reactor to 90℃, add 1g of benzoyl peroxide and react for 4h, cool to 52℃ and distill under reduced pressure, and add 3g of 52# paraffin and 1g of hydroquinone monomethyl ether at this temperature.

[0062] S12. After cooling the mixture obtained in step S11 to room temperature, add 2g of N,N-dimethylaniline and stir at 400r / min for 20min to obtain MMA prepolymer;

[0063] S13. Mix 80g of modified diluent with the MMA prepolymer obtained in step S12 and stir at 300r / min for 20min to obtain modified MMA resin;

[0064] S2. Mix 90g of mixed powder (composed of quartz sand, quartz powder and calcium powder, with masses of 50g, 25g and 15g respectively), 8g of barium sulfate and 12g of polyurethane rigid foam powder (obtained by recycling and crushing polyurethane foam insulation material from scrapped refrigerators and insulation boards) to obtain powder aggregate.

[0065] S3. Mix 120g of modified MMA resin, 4g of benzoyl peroxide and 400g of powder aggregate, stir at 300r / min for 3min, and after mixing evenly, obtain cold storage floor repair mortar.

[0066] Example 3

[0067] A method for preparing cold storage floor repair mortar:

[0068] Before preparing the cold storage floor repair mortar, the modified diluent and modified ester mixture should be prepared first:

[0069] The preparation of the modified diluent includes the following steps:

[0070] S1121. Add 0.6g of benzoyl peroxide in four portions to a reactor containing 90g of methyl methacrylate and 4g of tetrahydrofuran, then raise the temperature to 60℃ and maintain the reaction for 2h.

[0071] S1122. The solution obtained in step S1121 is kept at 50°C and subjected to vacuum distillation to remove unreacted monomers and volatiles, and finally the modified diluent is obtained;

[0072] The preparation of modified ester mixtures includes the following steps:

[0073] S111. Add 65g of methyl methacrylate, 9g of acrylic acid, 6g of n-butyl methacrylate, 11g of methyl acrylate, and 5g of triethylene glycol di-2-methacrylate to a reaction vessel, stir at 220r / min for 12min, and heat to 75℃ for 26min.

[0074] S112. Add 1.2g of benzoyl peroxide to 62g of methyl methacrylate and stir at 320r / min for 22min to obtain a monomer mixture;

[0075] S113. The monomer mixture is slowly added to the mixture obtained in step S111 at a dropping rate of 2 g / min. After reacting for 3.5 h, the temperature is lowered to 50 °C, and then vacuum distilled. After cooling to room temperature, the modified ester mixture is obtained.

[0076] S1. Preparation of modified MMA resin:

[0077] S11. Add 90g of modified ester mixture to the reactor, heat the reactor to 80℃, add 0.6g of benzoyl peroxide and react for 3.5h, cool to 50℃ and then distill under reduced pressure. At this temperature, add 2g of 52# paraffin and 0.6g of hydroquinone monomethyl ether.

[0078] S12. After cooling the mixture obtained in step S11 to room temperature, add 1.2g of ferric acetylacetone and stir at 320r / min for 17min to obtain MMA prepolymer;

[0079] S13. Mix 70g of modified diluent with the MMA prepolymer obtained in step S12 and stir at 260r / min for 17min to obtain modified MMA resin;

[0080] S2. Mix 77g of mixed powder (composed of quartz sand, quartz powder, and calcium powder, with masses of 42g, 22g, and 13g respectively), 6g of barium sulfate, and 11g of polyurethane rigid foam powder (obtained by recycling and crushing polyurethane foam insulation material from scrapped refrigerators and insulation boards) to obtain powder aggregate.

[0081] S3. Mix 110g of modified MMA resin, 3g of benzoyl peroxide and 320g of powder aggregate, stir at 220r / min for 2.5min, and after mixing evenly, obtain cold storage floor repair mortar.

[0082] Example 4

[0083] A method for preparing cold storage floor repair mortar:

[0084] Before preparing the cold storage floor repair mortar, the modified diluent and modified ester mixture should be prepared first:

[0085] The preparation of the modified diluent includes the following steps:

[0086] S1121. Add 0.8g of benzoyl peroxide in 5 portions to a reactor containing 95g of methyl methacrylate and 4.5g of tetrahydrofuran, then raise the temperature to 65℃ and maintain the reaction for 2h.

[0087] S1122. The solution obtained in step S1121 is kept at 50°C and subjected to vacuum distillation to remove unreacted monomers and volatiles, and finally the modified diluent is obtained;

[0088] The preparation of modified ester mixtures includes the following steps:

[0089] S111. Add 72g of methyl methacrylate, 9.5g of acrylic acid, 6.5g of n-butyl methacrylate, 11.5g of methyl acrylate, and 5.5g of triethylene glycol di-2-methacrylate to a reaction vessel, stir at 260r / min for 14min, and heat to 85℃ for 28min.

[0090] S112. Add 1.6g of benzoyl peroxide to 68g of methyl methacrylate and stir at 360r / min for 24min to obtain a monomer mixture;

[0091] S113. The monomer mixture is slowly added to the mixture obtained in step S111 at a dropping rate of 2 g / min. After reacting for 3.5 h, the temperature is lowered to 50 °C, and then vacuum distilled. After cooling to room temperature, the modified ester mixture is obtained.

[0092] S1. Preparation of modified MMA resin:

[0093] S11. Add 95g of modified ester mixture to the reactor, heat the reactor to 85℃, add 0.8g of benzoyl peroxide and react for 3.5h, cool down to 51℃ and distill under reduced pressure, and add 2.5g of 52# paraffin and 0.8g of hydroquinone monomethyl ether at this temperature.

[0094] S12. After cooling the mixture obtained in step S11 to room temperature, add 1.8g of triethylenediamine and stir at 360r / min for 18min to obtain MMA prepolymer;

[0095] S13. Mix 75g of modified diluent with the MMA prepolymer obtained in step S12 and stir at 280r / min for 18min to obtain modified MMA resin;

[0096] S2. Mix 86g of mixed powder (composed of quartz sand, quartz powder, and calcium powder, with masses of 48g, 24g, and 14g respectively), 7g of barium sulfate, and 11.5g of polyurethane rigid foam powder (obtained by recycling and crushing polyurethane foam insulation material from scrapped refrigerators and insulation boards) to obtain powder aggregate.

[0097] S3. Mix 115g of modified MMA resin, 3.5g of benzoyl peroxide and 370g of powder aggregate, stir at 280r / min for 2.5min, and after mixing evenly, obtain cold storage floor repair mortar.

[0098] Comparative Example 1

[0099] The only difference between Comparative Example 1 and Example 1 is that the modified diluent is replaced with methyl methacrylate monomer; the other steps are exactly the same in Comparative Example 1 and Example 1.

[0100] Comparative Example 2

[0101] The only difference between Comparative Example 2 and Example 1 is that polyurethane rigid foam powder was not added; the other steps are exactly the same in Comparative Example 2 and Example 1.

[0102] Performance testing:

[0103] According to GB / T 1346 (penetration test) and GB / T 17671, the low-temperature curing time and compressive strength of the cold storage floor repair mortars obtained in Examples 1-4 and Comparative Examples 1-2 were tested in a -5℃ constant temperature chamber. The specimens were controlled to be mortar blocks of 40×40×160mm. The results are shown in Table 1 below:

[0104] Table 1

[0105]

[0106] As shown in the table, Examples 1-4 all cured within 2 hours (120 minutes). Comparative Examples 1 and 2, due to the absence of modified diluent and polyurethane rigid foam powder, required significantly longer curing times for their cold storage floor repair mortars compared to the examples. Furthermore, this invention achieves a significantly lower odor while maintaining compressive strength comparable to existing technologies. This is because the modified diluent used in the cold storage floor repair mortar prepared in this invention has a higher molecular weight and a higher boiling point, resulting in weaker volatilization and thus reduced odor.

[0107] The bond strength of the cold storage floor repair mortars obtained in Examples 1-4 and Comparative Examples 1-2 was tested according to JC / T 985-2017, and the results are shown in Table 2 below:

[0108] Table 2

[0109]

[0110] Table 2 shows that the room temperature bonding strength and low temperature bonding strength of Examples 1-4 are significantly higher than those of Comparative Examples 1-2, especially at low temperatures where they are still greater than 3.2 MPa. This invention effectively solves the debonding problem.

[0111] The thermal conductivity and freeze-thaw cycle performance of the cold storage floor repair mortars obtained in Examples 1-4 and Comparative Examples 1-2 were tested according to GB / T 10294 and GB / T 50082-2009 to further evaluate their durability under low-temperature conditions. The results are shown in Table 3 below:

[0112] Table 3

[0113]

[0114] As can be seen from the experiments and Table 3, the cold storage floor repair mortars obtained in Comparative Example 1 and Comparative Example 2 showed cracking and pulverization of the specimens, respectively, proving that the present invention effectively prevents frost heave damage. Meanwhile, the thermal conductivity of the cold storage floor repair mortars obtained in Examples 1-4 was reduced by 50% compared to the comparative examples, achieving improved durability.

[0115] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a cold storage floor repair mortar, characterized in that, The preparation steps include the following: S1. Preparation of modified MMA resin: S11. By mass, add 80-100 parts of modified ester mixture to the reactor, heat the reactor to 70-90℃, add 0.5-1 parts of initiator and react for 3-4 hours, cool down to 48-52℃ and distill under reduced pressure, add 1-3 parts of 52# paraffin and 0.5-1 parts of polymerization inhibitor at this temperature. S12. After cooling the mixture obtained in step S11 to room temperature, add 1-2 parts of amine accelerator and stir at 300-400 r / min for 15-20 min to obtain MMA prepolymer; S13. Mix 60-80 parts of modified diluent with the MMA prepolymer obtained in step S12, and stir at a speed of 250-300 r / min for 15-20 min to obtain modified MMA resin; S2. Mix 72-90 parts of mixed powder, 5-8 parts of barium sulfate, and 10-12 parts of rigid polyurethane foam powder to obtain powder aggregate; S3. Mix 100-120 parts of modified MMA resin, 2-4 parts of initiator and 300-400 parts of powder aggregate, stir at a speed of 200-300 r / min for 2-3 min, and after mixing evenly, obtain cold storage floor repair mortar. The preparation of the modified ester mixture includes the following steps: S111. By weight, add 60-75 parts of methyl methacrylate, 8-10 parts of acrylic acid, 5-7 parts of n-butyl methacrylate, 10-12 parts of methyl acrylate, and 4-6 parts of triethylene glycol di-2-methacrylate to a reaction vessel, stir at 200-300 r / min for 10-15 min, and heat to 70-90℃ to react for 25-30 min; S112. Add 1-2 parts of initiator to 60-70 parts of methyl methacrylate, stir at 300-400 r / min for 20-25 min to obtain a monomer mixture; S113. The monomer mixture is slowly added to the mixture obtained in step S111 at a dropping rate of 2 g / min. After reacting for 3-4 h, the temperature is lowered to 50 °C, and then vacuum distilled. After cooling to room temperature, the modified ester mixture is obtained. The preparation of the modified diluent includes the following steps: S1121. By weight, add 0.5-1 parts of initiator in 4-5 portions to a reactor containing 80-100 parts of methyl methacrylate and 3-5 parts of tetrahydrofuran, then raise the temperature to 50-70℃ and maintain the reaction for 2 hours. S1122. The solution obtained in step S1121 is kept at 50°C and subjected to vacuum distillation to remove unreacted monomers and solvent volatiles, finally obtaining the modified diluent.

2. The method for preparing a cold storage floor repair mortar according to claim 1, characterized in that, The polymerization inhibitor is selected from hydroquinone monomethyl ether.

3. The method for preparing a cold storage floor repair mortar according to claim 1, characterized in that, The amine accelerator is selected from one or more of triethylenediamine, triethylamine, iron acetylacetone, N,N-dimethylaniline, N,N-dimethyl-p-toluidine, N,N-diethylaniline, and N,N-dihydroxyethyl-p-toluidine.

4. The method for preparing a cold storage floor repair mortar according to claim 1, characterized in that, The initiator is selected from benzoyl peroxide.

5. The method for preparing a cold storage floor repair mortar according to claim 1, characterized in that, The mixed powder in step S2 consists of quartz sand, quartz powder, and calcium powder, with a mass ratio of 40-50:20-25:12-15.

6. The method for preparing a cold storage floor repair mortar according to claim 1, characterized in that, The polyurethane rigid foam powder is obtained by recycling and crushing polyurethane foam insulation material from discarded refrigerators and insulation boards for reuse.

7. A cold storage floor repair mortar, characterized in that, The cold storage floor repair mortar is prepared by the preparation method described in any one of claims 1-6.

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